11,780 results on '"GARNET"'
Search Results
2. The use of He buffer gas for moderating the plume kinetic energy during Nd:YAG-PLD growth of EuxY2−xO3 phosphor films.
- Author
-
Suzuki, Shizuka, Dazai, Takuro, Tokunaga, Tomoharu, Yamamoto, Takahisa, Katoh, Ryuzi, Lippmaa, Mikk, and Takahashi, Ryota
- Subjects
- *
YTTRIUM aluminum garnet , *GARNET , *KINETIC energy , *ALUMINUM films , *MOLECULAR beam epitaxy , *PULSED laser deposition , *OXIDE coating , *PHOSPHORS - Abstract
We have investigated the He buffer gas process of moderating the kinetic energy of the pulsed laser deposition (PLD) plume during EuxY2−xO3 phosphor film growth. When using a neodymium yttrium aluminum garnet laser for PLD thin film growth, the kinetic energy of the ablation plumes can be high enough to cause the formation of point defects in the film. The buffer gas pressure is an important process parameter in PLD film growth. We find that the presence of the He buffer gas reduces the kinetic energy of the laser deposition plume through many low-angle collisions in the gas phase by a factor of 7 without reducing the deposition rate. This is because He is much lighter than any of the elements in the plume and it does not affect the composition of the oxide films. Consequently, the resputtering of the Y2O3 film surface by the plume was significantly suppressed in the presence of the He gas moderator, leading to a decrease of the defect density in the Y2O3 films. The improvement of the film quality was verified by a systematic analysis of time-resolved photoluminescence (PL) data for EuxY2−xO3 composition–gradient films. The PL lifetime and intensity of Eu0.2Y1.8O3, which shows the highest PL intensity, increased by 13.3% and 36.4%, respectively, when the He gas moderation process was used. The He buffer gas process is applicable to the PLD growth of the other oxide materials as well, where the reduction of the kinetic energy of the plume would bring the PLD process closer to the molecular beam epitaxy growth condition. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Thermally generated magnonic spin currents in a polycrystalline gadolinium iron garnet thin film with perpendicular magnetic anisotropy.
- Author
-
Chanda, Amit, Holzmann, Christian, Schulz, Noah, Stein, David, Albrecht, Manfred, Phan, Manh-Huong, and Srikanth, Hariharan
- Subjects
- *
PERPENDICULAR magnetic anisotropy , *MAGNETIC films , *THIN films , *IRON , *GARNET , *RAPID thermal processing - Abstract
Rare-earth iron garnets (REIGs) are the benchmark systems for magnonics, including the longitudinal spin Seebeck effect (LSSE). While most research has focused on single-crystalline REIGs on complimentary garnet substrates, moving to more, cost-effective complementary metal-oxide semiconductor (CMOS)-compatible substrates is important to integrate REIG thin films with existing technology. In this regard, we grow a 130 nm-thick polycrystalline gadolinium iron garnet (GdIG) film on the Si/SiO2 substrate and investigate the temperature-dependent LSSE. Interestingly, the polycrystalline GdIG film exhibits perpendicular magnetic anisotropy (PMA) at room temperature which is induced by tensile in-plane (IP)-strain originating from the thermal-expansion mismatch between the GdIG film and the substrate during rapid thermal annealing. Further, a spin-reorientation transition from the out-of-plane IP direction below TS = 180 K is observed. Additionally, the film reveals a magnetic compensation temperature, T Comp , of ≈240 K. The LSSE voltage not only demonstrates a sign-inversion around T Comp , but also shows noticeable changes around T S. As compared to a single-crystalline GdIG film, the lower LSSE voltage for the polycrystalline GdIG is attributed to the higher effective magnetic anisotropy and enhanced magnon scattering at the grain boundaries. Our study not only paves the way for the cost-effective growth of CMOS-compatible REIG-based systems with PMA for magnonic memory and information processing applications, but also highlights the fact that the spincaloritronic and spin-insulatronic properties of the polycrystalline REIGs follow those of their single-crystalline counterparts with reduced spin-to-charge conversion efficiency through LSSE which can be tuned further by controlling the average gran size and interface engineering. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. Topaz as a Potential Abrasive for Cutting and Surface Treatment of Materials by AWJ Technology
- Author
-
Martinec, Petr, Sitek, Libor, Veselovský, František, Hlaváček, Petr, Foldyna, Josef, Klomínský, Josef, Gabor, Roman, Němcová, Lucie, Ruppenthalová, Lucie, Chaari, Fakher, Series Editor, Gherardini, Francesco, Series Editor, Ivanov, Vitalii, Series Editor, Haddar, Mohamed, Series Editor, Cavas-Martínez, Francisco, Editorial Board Member, di Mare, Francesca, Editorial Board Member, Kwon, Young W., Editorial Board Member, Tolio, Tullio A. M., Editorial Board Member, Trojanowska, Justyna, Editorial Board Member, Schmitt, Robert, Editorial Board Member, Xu, Jinyang, Editorial Board Member, Sitek, Libor, editor, Valentinčič, Joško, editor, Trieb, Franz H., editor, and Hloch, Sergej, editor
- Published
- 2025
- Full Text
- View/download PDF
5. Improved comprehensive performance of high entropy rare earth aluminate as T/EBC materials by phase structure regulation.
- Author
-
Zhao, Xiuyi, Yang, Zeshan, Yue, Wanqiang, Wang, Chao, and Wang, Zhanjie
- Subjects
- *
THERMAL conductivity , *CORROSION resistance , *THERMAL properties , *GRAIN size , *ALUMINATES , *GARNET - Abstract
To optimize the comprehensive performance of rare earth (RE) aluminates as thermal/environmental barrier coatings (T/EBCs), we engineered six kinds of novel high-entropy RE aluminate multiphase ceramics with the coexisting garnet and perovskite phases by regulating equivalent ionic radius of RE3+, and the relationship between the microstructure and thermal properties, as well as resistance to CMAS corrosion was investigated in-detail. The findings revealed that the garnet (5RE 0.2) 3 Al 5 O 12 content gradually decreased in multiphase ceramics with the increasing equivalent ionic radius of RE3+. The interaction between garnet and perovskite grains can decrease grain size, which in turn enhanced phonon scattering, thereby leading to the decrease in thermal conductivity. Moreover, the synergistic effect in the different dissolution rates of garnet and perovskite phases can form a dense garnet/apatite barrier layer at corrosion front, thereby contributing to CMAS corrosion resistance. These results provide a robust theoretical foundation for the advancement of next-generation T/EBCs. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
6. A novel approach for Al-doped sintering of garnet solid electrolyte.
- Author
-
Wu, Di, Liu, Zheng, Yang, Chen, Zhang, Zhenshuo, Fan, Donghua, Wang, Da, and Peng, Zhangquan
- Subjects
- *
SOLID electrolytes , *ALUMINUM oxide , *LITHIUM cells , *CRYSTAL grain boundaries , *GARNET , *CERAMICS - Abstract
Garnet based solid-state electrolyte Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 (LLZTO) is one of the most promising electrolytes for advanced all-solid-state lithium batteries. However, the ceramic electrolyte is difficult to densify under normal sintering conditions, and hence the Li+ transportation via grain boundary is significantly limited by the loose contact between electrolyte granules, resulting in a high Li+ ionic impedance. Herein, we report a novel 2-step approach to obtain a relatively dense LLZTO ceramic pellet by a special Al-doping method, in which the Al was derived from the erosion of the corundum milling beads by LiOH during ball milling. This approach enables the simultaneous distribution of the aluminum (Al) within the LLZTO lattice and uniformly within the grain boundary, serving as a sintering aid, effectively boosts the fusion of grain boundary and reduced the failure rate during the sintering process. The ceramic pellet had a conductivity of 8.13 × 10−4 S cm−1, higher than that without Al-doping or using Al 2 O 3 as dopant. This method provides an easier way to sinter the garnet ceramic electrolyte. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
7. Calcium‐ferrum‐alumina‐silicate (CFAS) corrosion behavior of Lu4Hf3O12 ceramics at 1400°C.
- Author
-
Wang, Chenkai, Chen, Zedong, Zhao, Wei, Li, Yang, and Zhou, Wei
- Subjects
- *
MELT infiltration , *CERAMICS , *MICROSTRUCTURE , *MELTING , *GARNET , *TEMPERATURE - Abstract
In this work, the corrosion behavior of rare‐earth Lu4Hf3O12 ceramic when exposed to a CaO‐FeO1.5‐AlO1.5‐SiO2 (CFAS) environment at a temperature of 1400°C was investigated, with a focus on exploring the associated phase transformation, microstructure evolution, and corrosion reaction mechanism. Results reveal that during the corrosion process, the CFAS melt infiltrates Lu4Hf3O12 particles through cracks, resulting in the formation of a continuous reaction layer. This reaction leads to the generation of several high‐melting‐point garnets, including HfO2, Lu3Al5O12, Ca3Fe2(SiO4)3 (Ca‐Fe garnet), and Ca3Al2Si3O12 (Grossular). These garnets effectively fill the voids within the Lu4Hf3O12 ceramics, preventing further infiltration of the CFAS melts. As time progresses, the rate of the reaction gradually increases, while the rate of infiltration consistently decreases. Consequently, a relatively stable corrosion layer is achieved, effectively impeding further corrosion. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
8. Synthesis of praseodymium doped lutetium and gadolinium aluminum garnets modified by scandium and boron to improve luminescence properties.
- Author
-
Inkrataite, Greta, Keil, Jan-Niklas, Kizalaite, Agne, Jüstel, Thomas, and Skaudzius, Ramunas
- Subjects
- *
QUANTUM efficiency , *SCANNING electron microscopes , *RIETVELD refinement , *LUMINESCENCE , *SURFACE morphology , *SCINTILLATORS - Abstract
The structural and luminescence properties of the Lu 3 Al 4 Sc 1 O 12 :Pr and Gd 3 Al 3 Sc 2 O 12 :Pr garnet scintillators co-doped with boron (B3+) ions were investigated. The addition of B3+ and Sc3+ to the structure has a positive effect on the luminescence properties, especially on the photo, radio emission intensities, quantum efficiency, and results in a reduction of the decay time, which is necessary for high-quality scintillators. Structural properties of garnets have been determined after X-ray diffraction analysis coupled with Rietveld refinement. Surface morphology analysis was performed using a scanning electron microscope and particle size was also determined. Elemental composition was confirmed by the ICP-OES technique. Reflection, excitation (in the UV and VUV range), emission (upon excitation by UV or X-rays), decay time, and quantum efficiency at room temperature were measured. Furthermore, the influence of temperature on excitation, emission, and decay curves was also analyzed. The obtained luminescence properties indicated positive effect caused by doping. [Display omitted] [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
9. The structural, mechanical and chemical stability properties of HEG and YIG in response to α-irradiation.
- Author
-
Zhang, Shengtai, Teng, Zhen, Tan, Yongqiang, Chen, Chen, Wu, Linzhen, and Zhou, Xiaosong
- Subjects
- *
CERAMIC materials , *WASTE treatment , *CHEMICAL stability , *CHEMICAL properties , *AMORPHIZATION , *RADIOACTIVE wastes - Abstract
Ceramic materials with excellent radiation resistance stability play an indispensable role in the treatment of nuclear waste. This article uses spark plasma sintering (SPS) to synthesize high-entropy (HE) Y 0.6 Gd 0.6 Sm 0.6 Eu 0.6 Dy 0. 6 Fe 5 O 12 (HEG) and traditional garnet Y 1.2 Nd 1.8 Fe 5 O 12 (YIG). Studied the effects of 2 MeV He2+ irradiation (1 × 1014 ions/cm2 - 1 × 1017 ions/cm2) on the crystal structure, mechanical properties, and chemical stability of ceramics. Research shows that the surface of YIG becomes completely amorphous under ∼30dpa irradiation. Under irradiation at∼30dpa, HEG underwent a small amount of amorphization (with an amorphization rate of 38 %), maintaining the structure of garnet, and the lattice expansion rate of HEG caused by irradiation was lower than that of YIG. After irradiation, the mechanical properties of HEG were improved, while YIG's hardness decreased due to its amorphous state. Radiation has almost no effect on the chemical stability of HEG, and its long-term release mechanism is dominated by diffusion. This study identified HEG as an ideal candidate substrate for immobilizing high-radioactive waste (HLW) the perspective of radiation resistance. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
10. Correlative characterization of plasma etching resistance of various aluminum garnets.
- Author
-
Stern, Christian, Schwab, Christian, Kindelmann, Moritz, Stamminger, Mark, Weirich, Thomas E., Park, Inhee, Hausen, Florian, Finsterbusch, Martin, Bram, Martin, and Guillon, Olivier
- Subjects
- *
SECONDARY ion mass spectrometry , *PLASMA etching , *ATOMIC force microscopy , *TRANSMISSION electron microscopy , *SEMICONDUCTOR manufacturing , *YTTRIUM aluminum garnet , *GARNET - Abstract
Plasma etching is a crucial step in semiconductor manufacturing. High cleanliness and wafer‐to‐wafer reproducibility in the etching chamber are essential in order to successfully achieve nanometer‐sized integrated functions on the wafer. The trend toward the application of more aggressive plasma compositions leads to higher demands on the plasma resistance of the materials used in the etching chamber. Due to its excellent etch resistance, yttrium aluminum garnet Y3Al5O12 (YAG) is starting to replace established materials like SiO2 or Al2O3 in this kind of application. In this study, reactive spark plasma sintering (SPS) was used to manufacture highly dense YAG ceramics from the respective oxides. In addition, yttrium was replaced with heavier lanthanoids (Er, Lu), intending to investigate the role of the A‐site cation in the garnet type structure on the plasma erosion behavior. The produced materials were exposed to fluorine‐based etching plasmas mimicking the conditions in the semiconductor manufacturing apparatus and the erosion behavior was characterized by atomic force microscopy (AFM), secondary ion mass spectrometry (SIMS), transmission electron microscopy (TEM), and profilometry. The induced chemical gradient in the samples is limited to a few nanometers below the surface, which makes its characterization challenging. For advanced analysis, we developed a correlative characterization method combining SIMS and scanning TEM (STEM)–energy‐dispersive spectroscopy (EDS) enabling us to examine the structural and chemical changes in the reaction layer locally resolved. In the case of lanthanoid aluminates, an altered reaction layer and reduced fluorine penetration compared to YAG were found. However, a correlation between the characteristics of the induced chemical gradient and the determined physical erosion rates was not evident. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
11. Chemical stability and leaching mechanism of YIG and HEG at different pH conditions.
- Author
-
Zhang, Shengtai, Teng, Zhen, Wu, Linzhen, Tan, Yongqiang, Chen, Chen, and Zhou, Xiaosong
- Subjects
- *
CHEMICAL stability , *DIFFUSION control , *DIFFUSION coefficients , *GARNET , *CERAMICS - Abstract
Designing waste forms using the cocktail effect of high‐entropy ceramics can improve the efficiency of ceramic waste forms. In this work, traditional garnet (Y1.2Nd1.8Fe5O12, YIG) and high‐entropy (HE) garnet (Y0.6Gd0.6Sm0.6Eu0.6Dy0.6Fe5O12, HEG) are synthesized through ignition and plasma sintering to form dense ceramic waste forms. The chemical stability of YIG and HEG was studied by using static leaching tests at pH = 3, 5, 7, 9, 11. The results indicate that acidic environments can increase the leaching rate of ceramics. Leaching behavior leads to a decrease in lattice volume, but the elements remain uniformly distributed. The leaching mechanism indicates that YIG and HEG are controlled by dissolution and surface effect in the early stage (1–7 days) of leaching. The leaching mechanism in the later stage (14–42 days) is characterized by diffusion control. The diffusion coefficient of long‐term leaching indicates that HEG is more suitable as the immobilization substrate for high‐level radioactive waste (HLW) than YIG. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
12. Achieving Flat Ultra‐Broadband NIR Emission in Cr3+ Doped Garnet‐Type Phosphors Enabled by Structural Regulation Toward Multi‐Functional Spectroscopy Applications.
- Author
-
Wang, Dongpeng, Yan, Liqing, Zhu, Ge, Ma, Song, Zhou, Na, Li, Shanshan, Li, Zhuowei, Cong, Yan, Bai, Xue, Han, Xiaoguang, and Dong, Bin
- Abstract
Cr3+‐activated near‐infrared (NIR) emitting phosphors are considered as one of the most potential light‐conversion materials for NIR phosphor converted light‐emitting diodes (NIR pc‐LEDs). However, it is still a challenge for a single Cr3+ ion to achieve a flat ultra‐broadband emission toward multi‐functional spectroscopy applications. Herein, a chemical unit co‐substituting strategy is utilized to regulate the crystallographic occupancy of Cr3+ ions, and a flat ultra‐broadband NIR emission is successfully realized with a record emission wavelength of 915 nm in garnet‐type phosphors Ca3Sc2‐
x Hfx Alx Si3‐x O12:y Cr3+ (0 ≤x ≤ 1, 0.02 ≤y ≤ 0.06), together with a large full width at half maximum (FWHM) regulation from 130 to 250 nm. The relation between the site occupation of Cr3+ ions in disordered [CaO8], [(Sc, Hf)O6] and [(Si, Al)O4] polyhedrons and the corresponding NIR emission are clarified by carefully evaluating the structural evolution, Raman spectra, electron paramagnetic resonance and time‐resolved emission lifetime spectra of Cr3+ ions. The corresponding crystal field strength of Cr3+ ions is investigated to further clarify the multi‐sites induced flat broadband NIR emission. Finally, a blue light pumped NIR pc‐LED is fabricated with a total output power of 37.58 mW and photoelectric conversion efficiency (PCE) of 13.67%@100 mA, which realizes the multi‐functional applications in night vision imaging, non‐destructive detection and palmprint vein recognition for assistant medical treatment. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
13. Monazite Beats Zircon Regarding Dating of Young Metamorphic Events—An Example From Polycyclic Granitic Gneiss of the Pohorje Mountains, Slovenia.
- Author
-
Li, Botao, Massonne, Hans‐Joachim, Zhang, Junfeng, Yuan, Xiaoping, and Luo, Tao
- Subjects
- *
METAMORPHIC rocks , *MUSCOVITE , *GNEISS , *MONAZITE , *IGNEOUS intrusions , *URANIUM-lead dating , *GARNET - Abstract
ABSTRACT The result of dating U–(Th)–Pb bearing minerals in metamorphic rocks frequently suffers from the interpretative relation of their growth to a specific metamorphic event. This problem occurs in the southern Pohorje Mountains. Therefore, granitic gneiss from this area was studied. Rims of zircon in these rocks gave U–Pb ages around 90 Ma interpreted as an indicator of Late Cretaceous metamorphism. However, in situ dating of monazite with LA–ICP–MS yielded Early Miocene U–Th–Pb ages consistent with contact metamorphism by magmas forming the Pohorje pluton. This is supported by geothermobarometry using compositions of garnet and muscovite in granitic gneiss. This method led to pressure–temperature conditions of 6.5 kbar and 625°C, in line with intrusion depths estimated for the southeastern part of the Pohorje pluton. Consequently, zircon was not suitable for dating the latest metamorphic event but monazite was. Furthermore, monazite dating suggests two main intrusion pulses of magmas differing by 2–3 Ma. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
14. Rodingitization of Neoproterozoic Al-Barramiya ophiolite metagabbro in the Eastern Desert of Egypt, Arabian-Nubian Shield.
- Author
-
Abuamarah, Bassam A., Seddik, Amany M.A., Azer, Mokhles K., Chen, Yi-Xiang, and Darwish, Mahmoud H.
- Subjects
- *
CHLORITE minerals , *ULTRABASIC rocks , *MAGNESITE , *PLAGIOCLASE , *SERPENTINITE , *GARNET - Abstract
The present work studies the rodingite that is recorded for the first time as being associated to Al-Barramiya Neoproterozoic ophiolite at Eastern Desert of Egypt, Arabian-Nubian Shield (ANS). Al-Barramiya ophiolite is one of the most important ophiolitic sequences exposed in the ANS. It is affected by different styles of alterations included carbonatization, listvenitization, chloritization and rodingitization. The Neoproterozoic ophiolitic rocks of Al-Barramiya district consists of serpentinized peridotite and metagabbros. Serpentinized peridotites are highly altered to assemblages of talc-carbonate rocks, listvenite and magnesite, while metagabbro is partly converted into rodingite. The field studies indicate that serpentinite and rodingite in Al-Barramiya area display high-strain cataclastic deformation. Rodingite consists of garnet, diopside, vesuvianite and chlorite with minor epidote, prehnite, actinolite and opaque minerals. The garnets and vesuvianite are mostly concentrated near the peripheries of the studied rodingite masses, while clinopyroxene, chlorite, epidote and prehnite gradually increase inwards due to progressive decreasing water/rock ratio as fluids originally buffered by serpentinite move towards equilibrium with gabbroic bulk chemistry. Some rodingite samples preserve a few relics of igneous textures of ophiolitic metagabbros. Garnets are distinguished into andradite, hydroandradite and grossular. Pyroxene is represented mainly by secondary clinopyroxene beside primary fresh relics of diopside; the latter has high Mg# (0.92–0.97) similar to ophiolitic clinopyroxene in the ANS. Rodingite is enriched in CaO, Fe2O3 and MgO but depleted in SiO2, Al2O3 and Na2O compared to associated metagabbro. The association of rodingite with serpentinites and metagabbros suggests that Al-Barramiya rodingite is genetically related to serpentinization of ultramafic rocks. The rodingitization occurred during ocean floor alteration contemporaneous with the serpentinization process. The superposition of cataclastic deformation on the altered rocks indicates that alteration preceded obduction and occurred on the seafloor of the suprasubduction zone where Al-Barramiya ophiolite was originally emplaced. During serpentinization the olivine in the peridotite broke down and released Mg2+ in the metasomatic fluids and clinopyroxene broke down producing Ca-rich fluids. These fluids react with the mafic protoliths and enrich them in MgO and CaO. Also, serpentinization fluids react with the plagioclase of the metagabbro, releasing Ca from the mafic source and concentrated it in the rodingitized samples. The positive Eu anomalies beside high Sr contents of the rodingite can be inherited from a plagioclase-rich protolith such as ophiolitic metagabbro. The enrichment of rodingite in Th and U indicates two distinct solutions affected the gabbroic protolith because the alteration of depleted peridotite to serpentinite cannot be an efficient source to enrich these elements. The present study indicates that the rodingitization process underwent lower greenschist facies conditions associating metamorphism that caused serpentinization and released Ca-rich metasomatic fluids. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
15. Origin and metamorphism of ophiolitic serpentinites from the Yuli belt, eastern Taiwan: new findings and tectonic implications.
- Author
-
Dewangga, Dominikus Deka, Tsai, Chin-Ho, Iizuka, Yoshiyuki, Sakaguchi, Ilona Talvikki, Kouketsu, Yui, Chung, Sun-Lin, Lee, Chi-Yu, Chang, Wen-Yen, and Chen, Huei-Fen
- Subjects
- *
SUBDUCTION , *SUBDUCTION zones , *SCHISTS , *PERIDOTITE , *SERPENTINITE , *GARNET , *OLIVINE - Abstract
Serpentinites associated with metamafic and metaplagiogranitic rocks occur sporadically within metasedimentary schists in the Yuli belt. Such metaigneous rocks are considered to represent ophiolitic protoliths and some contain high-pressure (HP) metamorphic minerals or assemblages. However, the origin and metamorphism of these serpentinites have long been a mystery. This study systematically investigates the four major serpentinite-bearing exposures at the Fengtien, Wanjung, Tsunkuanshan, and Chinshuichi. The results reveal that the serpentinites are of two different protoliths on the basis of relict chromian spinel composition. Cr-spinel compositions of the Fengtien and Tsunkuanshan samples are characterised by moderate Cr# [Cr/(Cr + Al)] (0.45–0.57), relatively high Mg# [Mg/(Mg+Fe2+)] (0.59–0.79), but low Fe3+# [Fe3+/(Fe3++Cr+Al)] (0.02–0.06), reflecting an abyssal peridotite type protolith. By contrast, Cr-spinel compositions of the Wanjung and Chinshuichi samples show high Cr# (up to 0.74) and Fe3+# (0.03–0.08), but low Mg# (<0.6), indicating a forearc mantle peridotite origin. Peak metamorphic conditions of the serpentinites are represented by the assemblage of antigorite + magnetite + chlorite + olivine + diopside, which is estimated as up to 550°C but the pressure cannot be constrained quantitatively. Based on field relations, it is inferred that the serpentinites, associated HP metaigneous rocks, and garnet-bearing metasedimentary schists were metamorphosed isofacially. Despite two origins, the peridotitic protoliths were all subjected to hydration and subduction processes. We suggest that precursors of the serpentinites, metaigneous rocks, and metasedimentary schists were juxtaposed and metamorphosed at intermediate to great depths (~35–55 km) of a subduction zone. Therefore, the Yuli belt serpentinites and associated rocks likely represent exhumed materials from a palaeo-subduction interface. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
16. Efficient and Thermally Stable Cr3+‐Doped Phosphor Achieved by Cation Substitution: Plant Lighting Application.
- Author
-
Dai, Xiangyi, Zou, Xikun, Wei, Mingkai, Zhang, Xuejie, Dong, Bin, Li, Xinming, Cong, Yan, Li, Dongyu, Zhao, Jie, Molokeev, Maxim S., and Lei, Bingfu
- Subjects
- *
QUANTUM efficiency , *LIGHT sources , *BOK choy , *PHOSPHORS , *PLANT growth - Abstract
Far‐red phosphor‐converted light‐emitting diodes are receiving increasing attention as an essential component of the next‐generation plant‐growth lights. However, developing far‐red phosphors with high quantum efficiency, low thermal quenching, and suitable emitting wavelength is crucial and urgent. Herein, a new far‐red phosphor BaY2Ga3.9GeO12:0.1Cr3+ with high internal quantum efficiency (98%) and thermal stability (90.2%@423K) is obtained via the substitution of CaO8 with bigger BaO8 dodecahedrons, which is attributed to variations in the lattice environment of Cr3+. Meanwhile, controllable emission tuning from 780 to 708 nm and enhanced luminescence performance are achieved due to the cation substitution can reduce the production of Cr4+ and modulate the lattice occupancy of the Cr3+ ions, and the enhancement of metal‐ligand interactions resulting in the enhancement of the crystal field and the breaking of the forbidden d‐d transition of Cr3+. The proof‐of‐concept demonstration of the pakchoi lighting experiment reveals the great potential of BaY2Ga3.9GeO12:Cr3+ phosphor in stimulating plant growth and pushing the yield. These results demonstrate the feasibility of cationic substitution to optimize the optical performance of Cr3+‐doped phosphors, providing an alternative strategy for designing efficient far‐red light sources for plant lighting. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
17. Relationship between structure and microwave dielectric properties of new low-K garnet-type Ca3Cr2Ge3O12 ceramics.
- Author
-
Liu, Yanjun, He, Guoqiang, Nie, Yuan, Zhang, Wenjie, Zhao, Ziqi, and Zhou, Huanfu
- Subjects
- *
REFLECTANCE spectroscopy , *RIETVELD refinement , *SPECIFIC gravity , *EVIDENCE gaps , *QUALITY factor , *DIELECTRIC properties , *CERAMICS , *GARNET - Abstract
In order to solve the problem of signal delay, a novel low-K Ca 3 Cr 2 Ge 3 O 12 ceramic for 5G and millimeter-wave communication was prepared by a solid-state reaction method. XRD and Rietveld refinement results confirm that it belongs to the garnet structure with the Ia-3d space group. The shrinkage rate of the sample sintered at 1350 °C reached 11.9 %, and the relative density exceeded 94.3 %. Excellent microwave dielectric properties were obtained. The permittivity was 8.38, the quality factor was 23,107 GHz, and the temperature coefficient of resonant frequency was −43.57 ppm/°C. The relationship between the crystal structure and microwave dielectric properties of ceramics was further studied. The results show that lattice vibration, stacking fraction and bond strength have a great influence on the Q × f value of ceramics, and the bond valence parameter is the key factor affecting the temperature stability. In addition, the theoretical quality factor of the ceramic can reach ∼13,0000 GHz by far-infrared reflection spectroscopy, and the ceramic has great research potential. The development of Ca 3 Cr 2 Ge 3 O 12 ceramics and the study of microwave dielectric properties have filled the research gap of related systems. The excellent microwave dielectric properties indicate that it can be used as an alternative material for the preparation of components in the field of communication. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
18. Ga/Al ratio induced afterglow behavior of Ce3+:GAGG scintillation ceramics.
- Author
-
Tang, Yang, Qiang, Ming, Lou, Wenhui, Ding, Yuchong, Lin, Hui, Hong, Ruijin, and Zhang, Dawei
- Subjects
- *
FLUORESCENCE spectroscopy , *GALLIUM , *OPTICAL properties , *GARNET , *CERAMICS , *GADOLINIUM - Abstract
This work investigated the optical and scintillation properties of cerium-doped gadolinium aluminum gallium garnet (Ce:GAGG) ceramics with different gallium-to-aluminum (Ga/Al) ratios. The optical transmittance, fluorescence spectra, fluorescence lifetime, light yield, scintillation decay, and afterglow characteristics of the ceramic samples were studied. The experimental results reveal that the decay time of Ce:GAGG ceramic is significantly decreased with the increase of Ga content. The mean decay time of 60 ns is achieved when the Ga/Al ratio is 3:2 in our experiment. The light yield of ceramics varies from 12,140 to 44,825 ph/MeV with the change of Ga content, and the highest light yield is achieved when the Ga/Al ratio is 2.4:2.6. Noteworthy fluctuation in the afterglow performance is affected by the Ga content significantly. The afterglow intensity of the sample with Ga/Al = 2:3 is approximately 0.5 % of its initial intensity after the X-ray excitation was turned off for 5 s. The formation mechanism of defects which is related with the afterglow behaviors were investigated and discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
19. 含镓石榴石系列大晶格常数磁光衬底单晶研究进展.
- Author
-
李泓沅, 孙敦陆, 张会丽, 罗建乔, 权 聪, and 程毛杰
- Subjects
- *
THIN films , *SUBSTRATES (Materials science) , *LATTICE constants , *SILICON oxide , *MAGNETOOPTICAL devices , *GARNET - Abstract
With the rapid advancement of optical communication technology and integrated electronic devices, magneto-optical thin films, particularly rare earth iron garnet (RIG), have emerged as the most promising materials for near-infrared communication windows in recent years. In order to minimize the impact on the related properties of magneto-optical thin films during the preparation process, it's important to select the substrate materials. Silicon and garnet oxides are commonly used as substrates for the preparation of RIG magneto-optical thin films. The lattice constant of RIG magneto-optical thin films is generally around 12. 4 Å, and gallium-containing garnet oxide single crystal substrates have a similar lattice constant, which shows large lattice constant characteristics, making them one of the suitable substrate materials. However, the raw material gallium oxide is volatile at high temperature, the preparation of gallium-containing garnet single crystal has been a hot topic. The further study of gallium garnet series substrate single crystals is expected to promote the development of a new magnetooptical devices. In this paper, we reviewed the research of gallium garnet series single crystal, summarized the work of our team in the growth, structure and key parameters of these crystals, and outlooked the trend of research and development. [ABSTRACT FROM AUTHOR]
- Published
- 2024
20. Sm‒Nd Age of Sviatonossites of the Svyatoi Nos Peninsula (Eastern Baikal Region).
- Author
-
Levitskiy, V. I., Kovach, V. P., Kotov, A. B., Reznitsky, L. Z., Levitskiy, I. V., and Zagornaya, N. Y.
- Subjects
- *
ORTHOCLASE , *IGNEOUS rocks , *PYROXENE , *MINERALS , *ZIRCON , *APATITE , *GARNET - Abstract
Sviatonossites are syenites with andradite garnet, a rare type of igneous rocks described by P. Eskola in 1913 on the Svyatoi Nos Peninsula (Lake Baikal). Due to the absence of zircon in the rocks, which makes it possible to date them reliably by the U‒Pb method, geochronological Sm–Nd studies of the bulk composition and minerals are carried out. As a result, two estimated periods of the formation of sviatonossites are obtained. According to the bulk composition and four minerals (garnet, pyroxene, potassium feldspar, and apatite), the age is 262 ± 21 Ma (RMSD = 1.6), and according to the bulk composition and garnet, it is 274 ± 25 Ma (RMSD = 0). The results obtained coincide with the timing of tectonic–metamorphic and igneous processes associated with the formation of the Eastern Transbaikalia segment of the Central Asian (Mongol–Okhotsk) folded belt. Sviatonossites in the complexes of mobile (folded) belts framed by the Siberian Craton are indicator rocks reflecting the manifestation of mantle–crustal interaction. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
21. Storage Effects on the Physicochemical Properties, Phytochemical Composition, and Sugars in Red-Fleshed Cultivars, 'Rubycot' Plumcot, and 'Queen Garnet' Plum.
- Author
-
Kodagoda, Gethmini Kavindya, Hong, Hung Trieu, O'Hare, Tim J., Topp, Bruce, Sultanbawa, Yasmina, and Netzel, Michael Erich
- Subjects
- *
STONE fruit , *GARNET , *CULTIVARS , *CAROTENOIDS , *PLUM - Abstract
Domestic storage conditions can have a significant impact on the composition of phytochemicals and sugars in stone fruits. This study aimed to evaluate the effect of two domestic storage temperatures (4 and 23 °C) on the physicochemical properties, phytochemical composition, and sugars of 'Rubycot' (RC) plumcot, a novel stone fruit variety, and 'Queen Garnet' (QG) plum. Initially, RC had a lower total anthocyanin concentration (TAC) than QG, but TAC in RC increased significantly (p < 0.05) during storage, peaking at +95% after 7 days at 23 °C, while QG reached +60% after 14 days. At 4 °C, TAC increased for both varieties (RC +30%, QG +27%). RC had a higher initial total phenolic content (TPC), which also increased for both fruits. QG had a significantly higher initial total quercetin concentration (TQC), increasing by 40% (p < 0.05) at 23 °C. The initial total carotenoid concentration in QG was higher than that in RC, but after 10 days at 23 °C, RC had a higher carotenoid concentration than QG. Both varieties showed similar sugar profiles, with QG starting higher but decreasing over time at both storage temperatures. Results from this study showed that ambient storage significantly increases total anthocyanins, total quercetins, and TPC in RC and QG. However, it is important to evaluate the textural and sensory properties of stored RC and QG in terms of consumer acceptability of the stored fruits. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
22. Unraveling the Defect‐Induced Spectral Tuning in a Ce‐Doped Garnet Solid‐Solution Phosphor.
- Author
-
Qin, Yonghong, Cao, Yaxin, Ning, Lixin, Wang, Xicheng, and Wang, Yuhua
- Subjects
- *
DENSITY functional theory , *SPECTRAL energy distribution , *PHOSPHORS , *GARNET , *THERMAL stability - Abstract
The increasing demand for white light‐emitting diode (WLED) has prompted the development of phosphors, in which Ce3+‐activated garnet has been representative and widely investigated. The optimization and improvement of performance have long been a focus in the phosphor area. However, the trade‐off of phosphor performance always exists and is difficult to satisfy simultaneously, thereby necessitating a better understanding of the design principles that tune spectra performance comprehensively. Herein, the defect‐induced spectral tuning mechanism in a Ce‐doped garnet solid‐solution phosphor Ca1.5‐xY1.5+xAl3.5+xSi1.5‐xO12:Ce3+ (CYAS:Ce3+) is promoted. The enhancement of luminescence intensity and thermal stability together with red‐shift of emission can be achieved by chemical unit co‐substitution of [Y3+‐Al3+] for [Ca2+‐Si4+], which originated from the increasing anti‐site vacancy. The related mechanism is fully elucidated by combining structural and spectral analysis with density functional theory (DFT) calculations. This study provides a subtle control for the performance‐tuning of phosphors, which can deepen the understanding of the design principle inside‐out and the subsequent development and exploration of novel optoelectronic functional materials. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
23. Simultaneous NIR Emission and Thermal Stability Enhancement in Garnet‐Type NIR Phosphors through the Synergistic Effect of Lattice Distortion and Enhanced Rigidity.
- Author
-
Wang, Yining, Xu, Zheng, Shang, Mengmeng, Sun, Yixin, Xing, Xiaole, Dang, Peipei, and Lin, Jun
- Subjects
- *
QUANTUM efficiency , *THERMAL stability , *LUMINESCENCE , *SOLID solutions , *CALCIUM ions - Abstract
Even though there have been significant advancements in the development of Cr3+‐activated near‐infrared (NIR) phosphors, the challenge still remains to develop highly efficient and thermally stable NIR phosphors. Here, the Ca4‐xZnxHfGe3O12:0.03Cr3+ solid solution phosphors with 834–806 nm NIR emission are constructed by substituting Zn2+ for Ca2+, thereby facilitating the formation of [ZnO6] luminescence site. The coexistence of [HfO6] and [Zn/CaO6] luminescence centers is confirmed through DFT calculation, time‐resolved photoluminescence (TRPL) spectroscopy, and low‐temperature‐photoluminescence (77 K) spectroscopy. The formation of [ZnO6] effectively resolves the issue of lattice mismatch between Cr3+ and Ca2+. Furthermore, the simultaneous enhancement of luminescence intensity and thermal stability is realized through a synergistic combination of lattice distortion and rigidity enhancement. By optimizing the substitution concentration of Cr3+, the internal quantum efficiency (IQE) of 92% and an external quantum efficiency (EQE) of 29% are finally achieved. Meanwhile, the thermal stability is also enhanced from 59%@400 K (x = 0) to 81%@400 K (x = 0.8). The developed NIR phosphor‐converted light‐emitting diodes (pc‐LEDs) exhibit promising prospects in the fields of security, biomedicine, non‐destructive testing and rapid identification. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
24. Gamma-enhancement of reflected light images as a routine method for assessment of compositional heterogeneity in common low-reflectance Fe-bearing minerals.
- Author
-
Zhu, Qiaoqiao, Xie, Guiqing, Cook, Nigel J., Ciobanu, Cristiana L., and Wang, Hui
- Subjects
- *
ATOMIC mass , *OPTICAL images , *ELECTRIC conductivity , *VISIBLE spectra , *WOLFRAMITE - Abstract
The incorporation of impurity elements into minerals impacts their physical properties (e.g., reflectance, hardness, and electrical conductivity), but the quantitative relationships between these features and compositional variation remain inadequately constrained. Prior work has shown that gamma-enhancement of reflected light images represents a simple yet powerful tool to assess the compositional heterogeneity of single pyrite crystals, as it can enhance subtle differences in reflectance between distinct domains with different minor element concentrations. This study extends the gamma correction method to several other common Fe-bearing minerals, magnetite, garnet, wolframite, and tetrahedrite-tennantite, which all have far lower reflectance than pyrite. Gamma-enhanced optical images reveal clear variations in reflectance that are either systematic with increased minor element concentration, as the change in gray value on backscatter electron (BSE) images (in the case of magnetite, garnet, and tetrahedrite-tennantite) or contrasting (as in pyrite), yielding a convincing linkage between reflectance variation and compositional heterogeneity. Reflectance variation is an expression of the distribution of the average effective number of free electrons on the mineral surface that can re-emit light when excited by visible light. Gamma-enhanced images can reveal compositional heterogeneity in minerals such as wolframite where small atomic mass differences between substituting elements (Mn and Fe, in the case of wolframite) are virtually impossible to observe as a variation of gray values on BSE images. Results also demonstrate that Fe-rich domains in these minerals can be expected to have higher reflectance than Fe-poor domains whenever Fe is a major constituent. The greater reflectance is attributed to Fe ions having a greater effective number of free electrons than many other elements (e.g., Co, Ni, Si, Ca, Al, Mg, Mn, and As). This research highlights the utility of gamma correction as an inexpensive tool for routine evaluation of compositional heterogeneity in common Fe-bearing minerals, potentially obviating the necessity of a microbeam platform to correlate textures and composition. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
25. The lithology and composition of lunar mantle modified by ilmenite bearing cumulate: A thermodynamic model.
- Author
-
Huang, Wei and Du, Wei
- Subjects
- *
CORE-mantle boundary , *RADIOACTIVE elements , *BOUNDARY layer (Aerodynamics) , *ILMENITE , *PETROLOGY , *GARNET - Abstract
Due to their high density, the ilmenite-bearing cumulates (IBC) (with or without KREEP) formed during the late-stage lunar magma ocean solidification are thought to sink into the underlying lunar mantle and trigger lunar mantle overturn. Geophysical evidence implied that IBC may descend deep inside the Moon and remain as a partially molten layer at the core-mantle boundary (CMB). However, partial melting may have occurred on the mixed mantle cumulates during the sinking of IBC/KREEP and the silicate melt may be positively buoyant, thus preventing the IBC/KREEP layer from sinking to the CMB. Here, we perform thermodynamic simulation on the stability of lunar mantle cumulates at different depths mixed with different amounts of IBC/KREEP from an updated LMO model. The modeling results suggest that the sinking of IBC/KREEP will cause at least 5 wt% partial melting in the shallow (~ 120 km) and a much larger degree of partial melting in the deep lunar mantle (~ 420 km). Due to the density contrast with the surrounding mantle, IBC/KREEP-bearing melts could potentially decouple under certain conditions. The modified lunar mantle by sinking of IBC/KREEP can better explain the formation of different kinds of lunar basaltic magma than the primary lunar mantle formed through differentiation of lunar magma ocean. Sinking of IBC/KREEP back into the lunar mantle may introduce plagioclase, clinopyroxene, garnet, and incompatible radioactive elements into the deep lunar mantle, which will further affect the thermal and chemical evolution of the lunar interior. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
26. Transparent high entropy garnet ceramics by SPS.
- Author
-
Li, Jiao, Fiato, Matthew, and Wu, Yiquan
- Subjects
- *
GARNET , *ENTROPY , *CERAMIC powders , *TRANSPARENT ceramics , *CERAMICS , *NANOPARTICLE size - Abstract
High entropy or multi-principles component oxides as a new class of materials have been widely investigated for various applications due to their unique properties and multi-functionalities in recent years. In this study, a high entropy transparent ceramics ((Gd 0.2 Tb 0.2 Y 0.2 Lu 0.2 Yb 0.2) 3 Al 5 O 12) has been fabricated by spark plasma sintering (SPS) using co-precipitation synthesized powders. The powder preparation process was studied by TAG-DSC and FTIR. The phase structure, morphology, and element distribution of the obtained powder and ceramic samples are explored by XRD, SEM, and EDS mapping. It shows that the high entropy oxide (HEO) ceramic powder has a pure garnet phase, nanoparticle size, and homogenous elements distribution. The sintered ceramic exhibits the highest in-line transmittance in the visible and IR range of approximately 52 % at 700 nm and 74 % at 3.6 μm, respectively. In addition, characteristic optical properties of the final ceramics were demonstrated by photoluminescence spectroscopy. This work indicated that high-entropy garnet transparent ceramics with multi-wavelength emissions will provide more possibilities for multifunctional optical applications in the future. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
27. Corrosion resistance and microstructural evolution of Yb-Al-Si-O glass-ceramics under molten Ca-Mg-Al-Si environment at 1350 °C.
- Author
-
Meng, Xinyu, Ma, Yujie, Guo, Chun, Chen, Bo, Yang, Shaobo, Deng, Juanli, and Fan, Shangwu
- Subjects
- *
CORROSION resistance , *GLASS-ceramics , *SOLID solutions , *HIGH temperatures , *MULLITE , *GARNET - Abstract
The intrinsic characteristics of Yb 2 O 3 -Al 2 O 3 -SiO 2 (YbAS) glass-ceramics and their resistance to corrosion by molten calcium magnesium aluminosilicate (CMAS) at 1350 °C were systematically investigated. YbAS glass-ceramics, characterized by diverse compositions, maintaining phase stability over extended durations at elevated temperatures. After CMAS corrosion for 50 h, the main reaction phases were CaAl 2 Si 2 O 8 and Ca 2 Yb 8 (SiO 4) 6 O 2 , accompanied by multiple ion solid solution garnet in certain components. The glass component positioned along the eutectic line of Yb 2 Si 2 O 7 and mullite, with an OB value marginally exceeding that of CMAS, exhibits superior corrosion resistance to CMAS. This finding offers valuable insights for the subsequent design of environmental barrier coatings (EBCs). [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
28. Structural, magnetic and impedance dynamics of multiferroic high entropy garnet ceramics.
- Author
-
Verma, Shalini and Ravi, S.
- Subjects
- *
CERAMIC materials , *LATTICE constants , *TRANSITION temperature , *SPACE groups , *CRYSTAL structure , *GARNET - Abstract
We have synthesized (G d 0.2 Y 0.2 N d 0.2 D y 0.2 R 0.2) 3 F e 5 O 12 (R = E r , S m and Pr) high entropy garnet ceramic samples via solid-state reaction route for the first time. All the samples are formed in a single phase and exhibit a simple cubic crystal structure with an I a 3 ‾ d space group. The lattice constant of these samples varies as per the ionic radii of the substituted element and ranges in between 12.4458 Å to 12.5062 Å. The morphology and elemental contributions are also investigated for all the high entropy samples. Additionally, magnetization data reveal a similar value of room temperature saturation magnetization i.e., ∼ 16 e m u / g for (G d 0.2 Y 0.2 N d 0.2 D y 0.2 R 0.2) 3 F e 5 O 12 (R = S m and Pr) samples and it becomes 13.67 e m u / g for Er doped sample. This variation is understood with Dionne's sublattice magnetization model where the molecular weight of the substituent will affect the saturation magnetization. Furthermore, a deviation from ideal Debye-type relaxation behavior is noticed in room temperature Nyquist plots for all three samples. An anomaly in the dielectric plot around ferrimagnetic transition temperature indicates the multiferroic behavior of these high entropy ceramic materials. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
29. Thermal Conductivity of YAG:Nd + Mo Ceramic Composites Obtained by Spark Plasma Sintering.
- Author
-
Alekseeva, L. S., Nokhrin, A. V., Orlova, A. I., Boldin, M. S., Lantcev, E. A., Murashov, A. A., Chuvil'deev, V. N., Tabachkova, N. Yu., Sakharov, N. V., and Moskvichev, A. A.
- Abstract
The microstructure and thermophysical properties (specific heat capacity, thermal diffusivity, thermal conductivity) of fine-grained ceramic composites based on yttrium-aluminum garnet Y
2.5 Nd0.5 Al5 O12 (YAG:Nd) with different molybdenum contents (10, 20 and 40 vol %) were studied. Submicron garnet powders of Y2.5 Nd0.5 Al5 O12 were obtained by the coprecipitation method; YAG:Nd + Mo powder compositions with the YAG:Nd core–Mo shell structure were obtained by deposition of molybdenum onto the surface of garnet particles; samples of ceramic composites were obtained by the method of spark plasma sintering (SPS). Electron microscopy and X-ray phase analysis were used to study the microstructure and phase composition of the composites. YAG:Nd + Mo composites have a high relative density (98.1–99%) and a uniform fine-grained microstructure with a garnet grain size of 2–3 μm. Sintered YAG:Nd + Mo composites at room and elevated temperatures (up to 1100°C) have a high thermal conductivity coefficient exceeding the thermal conductivity coefficient of uranium dioxide UO2 , which allows using these materials as heat-resistant inert fuel matrices. It was shown that higher thermal conductivity of composites is ensured at a content of at least 20 vol % Mo. In composites with the addition of 20 and 40% Mo, the thermal conductivity coefficient at 1100°C reaches 7.0 and 8.8 W m–1 K–1 , respectively. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
30. Compositional Engineering of Lithium Metal Anode for High‐Performance Garnet‐Type Solid‐State Lithium Battery.
- Author
-
Kong, Wenhan, Wang, Suqing, Liu, Haixing, Liu, Yangxi, Jiang, Zhouyang, Mai, Xiuqiong, and Wang, Haihui
- Subjects
- *
ELECTROCHEMICAL electrodes , *ENERGY density , *LITHIUM cells , *KIRKENDALL effect , *ALUMINUM nitrate , *GARNET - Abstract
Garnet‐type solid‐state lithium batteries (SSLBs) possess excellent potential owing to their safety and high energy density. However, fundamental barriers are deficient cycling stability and poor rate capability. The main concern lies in generating voids at the Li|garnet interface during Li stripping, stemming from the sluggish diffusion of Li atoms inside the bulk Li metal. Herein, a composite anode (AN@Li) containing Li–Al alloy, Li3N, and LiNO2 is designed by introducing aluminum nitrate into molten Li. The lower interfacial formation energies exhibited by Li–Al alloy, Li3N, and LiNO2 with garnet solid‐state electrolyte (SSE) enhance the wettability of AN@Li toward SSE. Meanwhile, it affords efficient conductive pathways that facilitate Li+ diffusion in the bulk anode (not just on the surface). Impressively, the resulting symmetric cell with AN@Li electrodes achieves high critical current density (1.95 mA cm−2) and long cycle life (6000 h at 0.3 mA cm−2). The SSLB coupled with LiFePO4 cathode and AN@Li anode enables stable cycling for 200 cycles at a high rate of 1 C with a retention of 96% and exhibiting outstanding rate capability (145.9 mAh g−1 at 2 C). This work provides practical insights for producing high‐performance lithium metal anode for advanced garnet‐type SSLBs. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
31. Growth of GSAG:Ce scintillation crystals by the Bridgman method: influence of Ce concentration and codoping.
- Author
-
Hovhannesyan, K. L., Derdzyan, M. V., Badalyan, G., Kharatyan, G., Pejchal, J., Nikl, M., Dujardin, C., and Petrosyan, A. G.
- Subjects
- *
SINGLE crystals , *CROSS-entropy method , *GARNET , *SCANDIUM , *CRYSTALS - Abstract
Single crystals of Ce-doped gadolinium scandium aluminum garnet (Gd3Sc2Al3O12; GSAG) with Ca2+, Mg2+ and Li+ co-dopants were grown by the Bridgman method. Regardless of melt composition, crystals tend to grow close to the congruent composition. Introduction of Ca2+ or Mg2+, as in other Ce-doped garnets, leads to an increase of absorption below 350 nm, which may indicate formation of Ce4+ states, while no effect is seen with Li+ co-doping. High Ce concentration and co-doping accelerate the scintillation rise and decay times; the codopants strongly significantly reduce the afterglow. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
32. Solvent-Free Method of Polyacrylonitrile-Coated LLZTO Solid-State Electrolytes for Lithium Batteries.
- Author
-
Wang, Xuehan, Zhang, Kaiqi, Shen, Huilin, Zhang, Hao, Yao, Hongyan, Chen, Zheng, and Jiang, Zhenhua
- Subjects
- *
SOLID electrolytes , *IONIC conductivity , *LITHIUM cells , *MANUFACTURING processes , *CRYSTAL grain boundaries , *POLYELECTROLYTES , *GARNET - Abstract
Solid-state electrolytes (SSEs), particularly garnet-type Li6.4La3Zr1.4Ta0.6O12 (LLZTO), offer high stability and a wide electrochemical window. However, their grain boundaries limit ionic conductivity, necessitating high-temperature sintering for improved performance. Yet, this process results in brittle electrolytes prone to fracture during manufacturing. To address these difficulties, solvent-free solid-state electrolytes with a polyacrylonitrile (PAN) coating on LLZTO particles are reported in this work. Most notably, the PAN-coated LLZTO (PAN@LLZTO) electrolyte demonstrates self-supporting characteristics, eliminating the need for high-temperature sintering. Importantly, the homogeneous polymeric PAN coating, synthesized via the described method, facilitates efficient Li+ transport between LLZTO particles. This electrolyte not only achieves an ionic conductivity of up to 2.11 × 10−3 S cm−1 but also exhibits excellent interfacial compatibility with lithium. Furthermore, a lithium metal battery incorporating 3% PAN@LLZTO-3%PTFE as the solid-state electrolyte and LiFePO4 as the cathode demonstrates a remarkable specific discharge capacity of 169 mAh g−1 at 0.1 °C. The strategy of organic polymer-coated LLZTO provides the possibility of a green manufacturing process for preparing room-temperature sinter-free solid-state electrolytes, which shows significant cost-effectiveness. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. Pressure–Temperature–Time Evolution of a Polymetamorphic Paragneiss With Pseudomorphs After Jadeite From the HP–UHP Gneiss‐Eclogite Unit of the Variscan Erzgebirge Crystalline Complex, Germany.
- Author
-
Massonne, Hans‐Joachim
- Subjects
- *
MUSCOVITE , *ELECTRON probe microanalysis , *PSEUDOMORPHS , *MINERALS , *ECLOGITE , *GARNET - Abstract
ABSTRACT A quartz‐rich paragneiss from the Variscan Erzgebirge Crystalline Complex (ECC) was studied in detail because of abundant millimetre‐sized and clearly oriented pseudomorphs after a sodic mineral interpreted to have been jadeite. This mineral, or pseudomorphs after it, is rarely found in extensive high‐pressure (HP)–ultrahigh‐pressure (UHP) terranes worldwide despite reported pressure–temperature (P–T) conditions suitable for the formation of jadeite in common paragneisses and orthogneisses. In the studied rock, which contains abundant large and oriented potassic white mica flakes and minor millimetre‐sized garnet grains, the pseudomorphs consist of clusters of small albite grains with thin phengitic muscovite flakes in between. X‐ray maps for Ca and Mg in garnet demonstrate that an early generation of this mineral (Gt1) was corroded and subsequently overgrown by a Ca‐richer generation (Gt2). White mica is phengite with maximum Si contents of 3.42 atoms per formula unit. P–T conditions of 0.85 GPa and 650°C and 1.7 GPa and 660°C were derived for the formation of Gt1 and Gt2 rim + Si‐rich phengite, respectively, using pseudosection modelling. The latter conditions representing the pressure peak experienced by the paragneiss are compatible with the original presence of jadeite and possibly paragonite as well. This metamorphic peak occurred at 338.4 ± 2.3 (2σ) Ma based on in situ dating of monazite grains with the electron microprobe. A single monazite age of 386.4 ± 10.5 (2σ) Ma is related to the formation of Gt1. Thus, a Late Devonian metamorphism is suggested here for the first time to have occurred in ECC gneisses before the major HP event in the Early Carboniferous. Furthermore, the study demonstrates that the eclogite‐facies gneisses of the Gneiss‐Eclogite Unit of the ECC experienced peak pressures of not more than 2 GPa in contrast to recent proposals of an extensive UHP area in this unit. In addition, it is suggested that the localized occurrence of UHP rocks surrounded by other lithologies otherwise lacking evidence for UHP conditions should be interpreted with caution with respect to their regional extent and significance. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
34. Al2O3/Y3Al5O12 (YAG)/ZrO2 composites by single-step powder synthesis and spark plasma sintering.
- Author
-
Vakhshouri, Maryam, Najafzadehkhoee, Aliasghar, Talimian, Ali, Pernia, Cristina López, Poyato, Rosalía, Gallardo-López, Ángela, Gutiérrez-Mora, Felipe, Prnova, Anna, and Galusek, Dušan
- Subjects
- *
SINTERING , *SOL-gel processes , *POWDERS , *GARNET , *MICROSTRUCTURE - Abstract
Alumina-yttrium aluminum garnet (YAG)-zirconia composites are often produced by the melt solidification method. In the present study, we investigated the fabrication of α-Al 2 O 3 /Y 3 Al 5 O 12 (YAG)/ZrO 2 composite by Spark Plasma Sintering (SPS) of powders synthesized by Pechini's sol-gel method. The ternary composites with homogenous microstructure and high density were produced by SPS at 1300 °C for 15 min. The addition of ZrO 2 promoted the sintering of composites, resulting in a higher density and, in turn, higher hardness. A change in the indentation fracture behavior as the result of ZrO 2 addition was observed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
35. Cr3+-Yb3+ energy transfer drives ultra-wideband thermally-stable NIR-emitting Sr3Sc2Ge3O12 garnet phosphors for pc-LED application.
- Author
-
Li, Li, Yang, Haoliang, Wang, Yongjie, Zhou, Xianju, Ling, Faling, Gao, Huajing, Yang, Zhiyu, Tang, Xiantong, and Hua, Yongbin
- Subjects
- *
PHOSPHORS , *ENERGY transfer , *LIGHT sources , *GARNET , *LIGHT emitting diodes , *THERMAL stability - Abstract
The development of medical, military, and other fields has greatly increased the demand for broadband near-infrared light sources. This article reports that Sr 3 Sc 2 Ge 3 O 12 : Cr3+ (SSGO: Cr3+), a broadband near-infrared phosphor with 850 nm as the luminescence center, has an emission spectrum covering 700–1200 nm and a full width at half maximum (FWHM) of 125 nm under 490 nm excitation. To further increase the FWHM value, Yb3+ is introduced into the phosphor of SSGO: Cr3+ to enable energy transfer from Cr3+ to Yb3+. After doping 1 % of Yb3+ onto the Sr2+ site, the near-infrared emission generated by the 4A 2 →4T 1 (4P) transition of Cr3+ and the near-infrared emission generated by the 2F 5/2 → 2F 7/2 transition of Yb3+ work so that the FWHM increases to 220 nm. In addition, the thermal stability of the phosphor after co-doping with Yb3+ is also greatly enhanced from 61.6 % to 75.1 % by comparing it to the Cr3+ single-doped sample. In addition, SSGO:0.08Cr3+, 0.01 Yb3+ was combined with a commercial 490 nm chip to prepare a broadband near-infrared light-emitting diode (pc-LED). [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
36. Low temperature garnet phase formation in Mn-substituted Y3Fe5-xMnxO12 nanoparticles via citrate combustion synthesis.
- Author
-
Khanduri, H., Dimri, Mukesh C., Kumar, Prashant, Tawale, J.S., and Pant, R.P.
- Subjects
- *
GARNET , *SELF-propagating high-temperature synthesis , *LOW temperatures , *MAGNETIC properties , *YTTRIUM iron garnet , *MAGNETIC anisotropy - Abstract
In this article, we report on the formation of a low-temperature garnet phase in Mn-substituted Y 3 Fe 5-x Mn x O 12 (x = 0, 0.05, 0.15, and 0.25) nanopowders. We studied the structural, microstructural, static, and dynamic magnetic properties of Mn-substituted Y 3 Fe 5-x Mn x O 12 (YIG) nanopowders calcined at two different temperatures. The Mn-substituted garnet powders were synthesized using the citrate combustion method followed by calcination at 800 and 1200 °C for 3 h. An increase in Mn substitution (x = 0.15, 0.25) favored the growth of a single garnet phase at low temperatures, even at 800 °C. The lattice constant of these samples ranged from 12.3815 to 12.3679 Å. Microstructural and morphological studies revealed the growth of homogeneous and dense particles, with an average particle size in the range of ∼35–58 nm, close to the single-domain particle size in YIG. Microwave resonance spectra and magnetic hysteresis curves revealed the formation of a ferromagnetic phase in undoped and Mn-doped garnet ferrites at room temperature. The maximum saturation magnetization (26 emu/g) was observed for the sample with Mn content x = 0.05 at 1200 °C, while the largest coercivity (33 Oe) was found for the sample with Mn content x = 0.15 at 1200 °C, among all the samples. The increase in Mn content led to a decrease in peak-to-peak linewidth of FMR spectra from 698.8 to 569.4 G at 800 °C and from 916 to 614.7 G at 1200 °C. This study suggests that Mn substitution in YIG garnet improves structural properties and enhances magnetic anisotropy. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. The Åker assemblage: Provenance and local workshop-traditions in the North Sea region in the late 6<bold>th</bold> and early 7<bold>th</bold> centuries.
- Author
-
Røstad, Ingunn Marit
- Subjects
- *
MIDDLE Ages , *ARCHAEOLOGICAL discoveries , *ARISTOCRACY (Social class) , *GARNET , *SCANDINAVIANS - Abstract
The so-called Åker assemblage, a collection of stray finds of weapon parts and warrior-related objects dating from c. AD 600, has held a prominent position in Norwegian archaeology since the discovery of the first objects on the estate of Åker in Hedmark in south-eastern Norway in the 19th century. The assemblage comprises high-status objects belonging to a warrior elite whose equipment display close similarities across the European Continent and in Anglo-Saxon England. In early research, many of the objects in the assemblage, e. g., the renowned ‘Åker buckle’ with cloisonné and zoomorphic decoration, were ascribed a Continental provenance. More recent discussions, however, advocate a Scandinavian origin for all the objects in the assemblage. Yet, the question of where the items originally were manufactured was once more actualized when further objects belonging to the assemblage were unearthed by metal detectorists in the 1990s. Among the new finds were some Frankish types of belt mounts that are unique in a Scandinavian perspective and other items with similarities to related equipment found in other regions. The new items may thus potentially shed new light on the question concerning place of origin of the assemblage. The question of provenance, however, is tied up with the phenomenon of local workshop-traditions in Scandinavia and the North Sea region. New insights have been gained on this topic during recent years as several new production sites have been explored. Through a visual assessment of the new items in the assemblage and a discussion of related parallels, it is argued here for a yet unknown western Scandinavian workshop as the most likely source for several of the objects making up the Åker assemblage. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
38. Contents list.
- Subjects
- *
PRUSSIAN blue , *GARNET , *CYCLIC peptides , *MATRIX-assisted laser desorption-ionization , *SILICA films , *ALCOHOL oxidation , *CHEMICAL detectors , *SCIENTIFIC community , *OXYGEN reduction - Published
- 2024
- Full Text
- View/download PDF
39. Creating a blue-light-excitable, ultra-broadband and relatively long-wavelength near-infrared emission in Cr3+-activated garnet by controlling cationic disorder.
- Author
-
Li, Chaojie and Zhong, Jiyou
- Subjects
- *
GARNET , *CHROMIUM isotopes , *BLUE light - Abstract
A series of garnet-type solid-solution materials, namely NaxCa3−2xGdxIn2Ge3O12:Cr3+ (0 ≤ x ≤ 1.5), were created by introducing cationic disorder into the dodecahedral site, and were found to exhibit a nearly unchanged excitation peak in the blue light region, a wide-range spectral tunability (800–905 nm) and an ultra-broadband spectral coverage (fwhmmax = 205 nm). [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. Composite Electrolytes with Li2CO3‐Free Garnets Achieved by One‐Step Poly(propylene carbonate) Treatment for High‐Rate and Long‐Life Solid Lithium Batteries.
- Author
-
Wang, Nan, Jia, Mengyang, Bi, Zhijie, and Guo, Xiangxin
- Subjects
- *
PROPYLENE carbonate , *POLYETHYLENE oxide , *IONIC conductivity , *POLYVINYLIDENE fluoride , *ION transport (Biology) , *SUPERIONIC conductors , *GARNET - Abstract
Garnet‐based composite electrolytes show great potential in building high‐energy‐density solid lithium batteries. However, naturally formed Li2CO3 on garnets owing to air exposure hinders the Li‐ion transport and triggers undesirable performance deterioration. Based on the reaction between basic Li2CO3 and poly(propylene carbonate) (PPC) with a product of propylene carbonate (PC), composite electrolytes with homogeneously distributed Li2CO3‐free garnets as well as PC are fabricated in one step without the post‐treatment of garnet powders in both polyethylene oxide (PEO) and polyvinylidene fluoride (PVDF)‐based electrolytes. The formed PC component further decreases the crystallization of PEO and reduces the grain size of PVDF, leading to improved ion transport in PEO and the suppression of PVDF dehydrofluorination. Consequently, the PPC‐treated garnets enable high ionic conductivities of 3.40 × 10−4 and 1.75 × 10−4 S cm−1 at 30 °C, respectively, in PEO:garnet and PVDF:garnet electrolytes, as well as great electrochemical stability against Li‐metal with a lifespan over 1000 h in Li symmetrical cells at 0.1 mA cm−2. Superior stable cycles are thus realized in both LiFePO4|PEO:garnet|Li and LiNi0.6Co0.2Mn0.2O2|PVDF:garnet|Li cells. These above results demonstrate that the one‐step treatment used here helps the enhancement of Li‐ion transport in composite electrolytes, thus essential for building high‐rate and long‐life solid lithium batteries (SLBs). [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. Magneto‐Optical Bi‐Substituted Yttrium and Terbium Iron Garnets for On‐Chip Crystallization via Microheaters.
- Author
-
Hayashi, Kensuke, Dao, Khoi Phuong, Gross, Miela J., Ranno, Luigi, Sia, Jia Xu Brian, Fakhrul, Takian, Du, Qingyang, Chatterjee, Nilanjan, Hu, Juejun, and Ross, Caroline A.
- Subjects
- *
YTTRIUM iron garnet , *PERPENDICULAR magnetic anisotropy , *RAPID thermal processing , *FARADAY effect , *CRYSTALLIZATION , *YTTRIUM aluminum garnet , *ANNEALING of metals , *GARNET , *IRON powder - Abstract
Ferrimagnetic iron garnets enable magnetic and magneto‐optical functionality in silicon photonics and electronics. However, garnets require high‐temperature processing for crystallization which can degrade other devices on the wafer. Here bismuth‐substituted yttrium and terbium iron garnet (Bi‐YIG and Bi‐TbIG) films are demonstrated with good magneto‐optical performance and perpendicular magnetic anisotropy (PMA) crystallized by a microheater built on a Si chip or by rapid thermal annealing. The Bi‐TbIG film crystallizes on Si at 873 K without a seed layer and exhibits good magneto‐optical properties with Faraday rotation (FR) of −1700 deg cm−1. The Bi‐YIG film also crystallizes on Si and fused SiO2 at 873 K without a seed layer. Rapidly cooled films exhibit PMA due to the tensile stress caused by the thermal expansion mismatch with the substrates, increasing the magnetoelastic anisotropy by 4 kJ m−3 versus slow‐cooled films. Annealing in the air for 15 s using the microheater yields fully crystallized Bi‐TbIG on the Si chip. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
42. Trace Fluorinated Carbon Dots Driven Li‐Garnet Solid‐State Batteries.
- Author
-
Zhu, Fangjun, Xu, Laiqiang, Hu, Xinyu, Yang, Mushi, Liu, Huaxin, Gan, Chaolun, Deng, Wentao, Zou, Guoqiang, Hou, Hongshuai, and Ji, Xiaobo
- Subjects
- *
ELECTRON transport , *DENDRITIC crystals , *DENSITY functional theory , *GARNET , *LEAKAGE - Abstract
Garnet solid‐state electrolyte Li6.5La3Zr1.5Ta0.5O12 (LLZTO) holds significant promise. However, the practical utilization has been seriously impeded by the poor contact of Li|garnet and electron leakage. Herein, one new type of garnet‐based solid‐state battery is proposed with high performance through the disparity in interfacial energy, induced by the reaction between trace fluorinated carbon dots (FCDs) and Li. The work of adhesion of Li|garnet is increased by the acquired Li‐FCD composite, which facilitates an intimate Li|garnet interface with the promoted uniform Li+ deposition, revealed by density functional theory (DFT) calculations. It is further validated that a concentrated C−Li2O−LiF component at the Li|garnet interface is spontaneously constructed, due to the significant disparity in interfacial energy between C−Li2O−LiF|LLZTO and C−Li2O−LiF|Li. Furthermore, The electron transport and Li dendrites penetration are effectively hindered by the formed Li2O and LiF. The Li‐FCD|LLZTO|Li‐FCD symmetrical cells demonstrate stable cycling performance for over 3000 hours at 0.3 mA cm−2 and 800 hours at 0.5 mA cm−2. Furthermore, the LFP|garnet|Li‐FCD full cell exhibits remarkable cycling performance (91.6 % capacity retention after 500 cycles at 1 C). Our research has revealed a novel approach to establish a dendrite‐free Li|garnet interface, laying the groundwork for future advancements in garnet‐based solid‐state batteries. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. Ultrafast One‐Step Synthesis of Garnet‐Type Solid Electrolytes With Modified Surface and Microstructure for Solid‐State Lithium‐Metal Batteries.
- Author
-
Kim, Jong Heon, Kim, Doosoo, Nanda, Siddhartha, and Khani, Hadi
- Subjects
- *
SOLID electrolytes , *INTERFACIAL resistance , *IONIC conductivity , *SUPERIONIC conductors , *CRITICAL currents , *LITHIUM cells - Abstract
Garnet‐type Li6.5La3Zr1.5Ta0.5O12 (LLZTO) solid electrolytes provide the necessary electrochemical stability and ionic conductivity for solid‐state lithium‐metal batteries (SSLMBs). However, their wider application is hindered by their high interfacial resistance with electrodes and a lengthy synthesis process. This study presents the synthesis of densified LLZTO electrolytes using unconventional Li2O and Li2ZrO3 precursors through an ultrafast (≈60 s) Joule heat‐assisted synthesis approach in a single‐step process. The lower sintering temperature of Li2ZrO3 compared to traditional ZrO2 precursor yields LLZTO with larger grains, resulting in enhanced Li+ conductivity (7.0 × 10−4 S cm−1 at 25 °C), reduced electronic conductivity (1.7 × 10−10 S cm−1), and higher density (94.2%). Applying a 52–80 nm Sn:SnF2 coating on the LLZTO surface using a melt‐quenching approach produces a uniform interlayer that chemically converts to Li‐Sn alloy and LiF upon contact with lithium, resulting in a near‐zero interfacial resistance and a critical current density of 4.2 mA cm−2 at 25 °C. The SSLMBs, incorporating Sn:SnF2‐coated LLZTO electrolyte with NMC811 cathode, demonstrate remarkable initial capacity (181.1 mAh g−1) and cycle performance (88.63% capacity retention at 3000th cycle). The results indicate that this approach has the potential to advance the commercial fabrication technology for high‐performance solid electrolytes for SSLMBs. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Co-training machine learning enables interpretable discovery of near-infrared phosphors with high performance.
- Author
-
Xu, Wei, Wang, Rui, Hu, Chunhai, Wen, Guilin, Cui, Junqi, Zheng, Longjiang, Sun, Zhen, Zhang, Yungang, and Zhang, Zhiguo
- Subjects
MACHINE learning ,GARNET ,PHOSPHORS ,LIGHT sources ,QUANTUM efficiency ,LUMINESCENCE - Abstract
Near-infrared (NIR) phosphors based on Cr
3+ doped garnets present great potential in the next generation of NIR light sources. Nevertheless, the huge searching space for the garnet composition makes the rapid discovery of NIR phosphors with high performance remain a great challenge for the scientific community. Herein, a generalizable machine learning (ML) strategy is designed to accelerate the exploration of innovative NIR phosphors via establishing the relationship between key parameters and emission peak wavelength (EPW). We propose a semi-supervised co-training model based on kernel ridge regression (KRR) and support vector regression (SVR), which successfully establishes an expanded dataset with unlabeled dataset (previously unidentified garnets), addressing the overfitting issue resulted from a small dataset and greatly improving the model generalization capability. The model is then interpreted to extract valuable insights into the contribution originated from different features. And a new type NIR luminescent material of Lu3 Y2 Ga3 O12 : Cr3+ (EPW~750 nm) is efficiently screened, which demonstrates a high internal (external) quantum efficiency of 97.1% (38.8%) and good thermal stability, particularly exhibiting promising application in the NIR phosphor-converted LEDs (pc-LED). These results suggest the strategy proposed in this work could provide new viewpoint and direction for developing NIR luminescence materials. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
45. The Fluid Evolution in the Skarn Stages of the Baoshan Skarn Cu-Polymetallic Deposit, South China.
- Author
-
Zheng, Ping, Chen, Ke, Zhang, Jun-Ke, Liu, Zhong-Fa, Li, Yong-Shun, and He, Ming-Peng
- Subjects
- *
SCHEELITE , *SKARN , *MINERALOGY , *COPPER , *PYROXENE - Abstract
Baoshan is a world-class skarn Cu-polymetallic deposit located at the junction of the Nanling and Qin-Hang metallogenic belts in China. While there has been extensive research on the mineralogy and geochemistry of skarn deposits, studies on the fluid characteristics and evolutionary history from the early to late skarn stages in such deposits are still limited. In this study, we analyzed garnet and pyroxene from the early skarn stage and scheelite from the late skarn stage of the Baoshan deposit. We distinguished two generations of garnet (Grt1 and Grt2), one generation of pyroxene, and three generations of scheelite (Sch I, Sch II, and Sch III) on the basis of mineral assemblages and microscopic characteristics. Grt1 appears coarse-grained, and Grt2 cuts through Grt1 as veinlets. In Grt1, the andradite end-member increases from the core to the rim, while the grossular portion decreases (Ad35–36Gr59–61Sp3–4 to Ad59–61Gr36–37Sp2–3), and in Grt2, the andradite end-member significantly increases (Ad41–73Gr25–55Sp2–3). Grt1 and Grt2 have similar trace element compositions, with enrichment in Zr and depletion in Nb and Hf, depletion in LREE, enrichment in HREE, and weak negative Eu anomalies. Pyroxene coexists with Grt1 and is similarly cut by Grt2, with its composition mainly being diopside (Di82–99Hd0.6–15Jo0–3.2). Sch I and Sch II appear as anhedral to subhedral grains, while Sch III is predominantly found in veinlets. In Sch I and Sch II, most REEs enter the scheelite lattice via the Na-REE coupled substitution mechanism, with a smaller portion substituting Ca vacancies. In Sch III, the substitution mechanism involving Ca site vacancies may dominate. During the early skarn stage, the oxygen fugacity of the fluid gradually decreased from Grt1 and pyroxene to Grt2. In the late skarn stage, fluid oxygen fugacity remains stable from Sch I and Sch II to Sch III in shallow parts but significantly decreases in deeper parts. The garnet and pyroxene from the Baoshan deposit align with typical skarn Cu deposit compositions, while scheelite in the late skarn stage shows Sch I, Sch II, and shallow Sch III as skarn-type and deep Sch III as vein-type scheelite. Early skarn stage fluids were weakly acidic. Sch I, Sch II, and Sch III originated from fluids related to the Baoshan granite porphyry, with Sch III also showing evidence of water–rock interaction. This study reconstructed the fluid evolution history from the early to late skarn stages at the Baoshan deposit, providing insights into the ore-forming processes of other skarn deposits. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. A record of Late Cretaceous to early Paleogene Insular terrane accretion within the northern Cordillera: Insights from monazite petrochronology across the Kluane Schist, southwest Yukon, Canada.
- Author
-
McKenzie, Will F., Dyck, Brendan, Gibson, H. Daniel, and Larson, Kyle
- Subjects
- *
PHASE equilibrium , *MONAZITE , *PALEOGENE , *GARNET , *LASER ablation inductively coupled plasma mass spectrometry , *SUBDUCTION - Abstract
The Kluane Schist is a metamorphosed package of siliciclastic and lesser calcareous rocks that lies between the inboard pericratonic Intermontane terranes and outboard Insular terranes of the North American Cordillera within Yukon, Canada. The metamorphic sequence of the Kluane Schist preserves a record of the tectono-thermal evolution and timing of Insular terrane accretion. Here we document the timing of metamorphism and deformation across the Kluane Schist using in situ laser ablation–inductively coupled plasma–mass spectrometry U-Th-Pb monazite petrochronology. Monazite-bearing samples collected across an inverted metamorphic sequence preserved in the northern regions of the Kluane Schist yield dates ranging from ca. 70 Ma to 55 Ma. Complementary phase equilibria modeling and thin section analysis indicate monazite grew between ∼450 °C and 3.0–3.5 kbar to ∼700–715 °C and 4.0–4.5 kbar, coeval with the development of the Kluane Schist’s inverted metamorphic sequence. Dating the four chemical zones preserved by monazite demonstrates its protracted growth during three distinct periods of garnet crystallization and breakdown, as well as coeval with melt generation. Our data illustrate that peak metamorphic conditions were reached at progressively younger ages with decreasing structural level within the Kluane Schist. Our results are consistent with Buchan-style metamorphism associated with the terminal accretion of the outboard Insular terranes and southwest-directed overriding of the inboard Yukon-Tanana terrane from ca. 70 Ma to 55 Ma. These findings are further congruous with a Late Cretaceous timing for the terminal accretion of the Insular terranes within southwest Yukon, facilitated by eastdipping subduction beneath a westward migrating North American continent. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
47. Experimental metasomatic alteration of titanite in a series of metamorphic fluids at 700 °C and 200 MPa.
- Author
-
Gmochowska, Wiktoria, Harlov, Daniel, Słaby, Ewa, Jokubauskas, Petras, Sláma, Jiří, and Łącki, Marcin
- Subjects
- *
RARE earth metals , *SPHENE , *METASOMATISM , *PEROVSKITE , *WOLLASTONITE , *GARNET - Abstract
Seven experiments exploring the reaction of titanite with various hydrothermal solutions have been carried out at 700 °C and 200 MPa for a run duration of 16 days. In experiments involving fluids consisting of NaCl+H2O, KCl+H2O, CaCl2+H2O, 2M NaOH, or 2M KOH, no reaction of the titanite with the fluid was observed other than a slight dissolution of the titanite. Experiments involving NaF+H2O and Ca(OH)2+H2O resulted in visible alteration of the titanite in texture and composition, coupled with the formation of perovskite. In the NaF+H2O experiment, perovskite, enriched with rare earth elements (REE), formed as euhedral to subhedral crystals on the surface of the recrystallized titanite. In the Ca(OH)2+H2O experiment perovskite took in minor amounts of REE, and formed as a reaction rim partially replacing the titanite via a coupled dissolution-reprecipitation reaction. Wollastonite, along with minor calcite, and grossular garnet, formed as an outer rim on the perovskite. In the NaF+H2O experiment major and trace elements were leached from the titanite, whereas in the Ca(OH)2+H2O experiment no leaching of major or trace elements was observed. Nb/Ta, Th/U, and Y/Ho were investigated as potential indicators of hydrothermal processes. While the Nb/Ta ratio was altered in the experimentally metasomatised titanite, the degree of alteration was the same for both fluids. In contrast, only small changes in the Th/U and Y/Ho ratios between the altered and original titanite were seen for either experiment. The formation of perovskite at the expense of titanite in NaF+H2O or Ca(OH)2+H2O fluids demonstrates how titanite reacts with these fluids in simple, low silica activity systems under mid to upper crustal P-T conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
48. Multiphase evolution of fluids in the Rudnik hydrothermal-skarn deposit (Serbia): new constraints from study of quartz-hosted fluid inclusions.
- Author
-
Petrović, Stefan, Bakker, Ronald J., Cvetković, Vladica, and Jelenković, Rade
- Subjects
- *
QUARTZ crystals , *FLUID inclusions , *GAS mixtures , *PYRRHOTITE , *SKARN , *GOLD ores , *GARNET , *SPHALERITE - Abstract
This study presents and discusses first detailed petrographic, microthermometric and Raman spectroscopic data from quartz-hosted fluid inclusions at Rudnik Zn-Pb-Cu-Ag skarn deposit (Serbia) and combines them with the information on skarn- and ore paragenesis. Three periods in the metamorphic-hydrothermal history of the deposit are recognized: 1) the pre-ore prograde skarn period when garnet-clinopyroxene skarns formed, 2) the syn-ore period that encompasses a retrograde stage marked by epidote and zoisite and a quartz-sulfide stage characterized by quartz, pyrrhotite, sphalerite, galena and chalcopyrite, and 3) the post-ore period associated with precipitation of calcite and quartz. The hydrothermal evolution is inferred from studying six groups of quartz-hosted fluid inclusions (FI). Two-phase FI of high- (Group A) and moderate salinity (Group B) are found in quartz cores and homogenized at 380–390 °C (mode) and 370–380 °C (mode), respectively. Group A FI consists of H2O-NaCl liquids and CO2-CH4 gas mixtures and likely represents the original fluid composition, whereas Group B FI records dilution of the original fluid at constant temperature, with a slight increase in CH4 contents. The quartz cores also contain Group C as volatile-rich FI (mostly CO2 with up to 10 mol% CH4 and H2S) of a moderately low salinity and liquid-rich Group D FI composed of pure water with homogenization temperatures of 180–200 °C (mode). The transitional zones of quartz crystals show overgrowth textures and host Group E FI with low salinity that homogenized at 235–401 °C, which vapour phase is a CO2-CH4 mixture with up to 17 mol% CH4. Group F comprises FI found within the rim zones of quartz crystals and they exhibit a low salinity and homogenization temperatures between 259–365 °C. Accordingly, the hydrothermal history at Rudnik involved: a) mixing of different salinity fluids at high temperatures (Groups A and B—retrograde stage), b) introduction of fluids with high volatile contents (Group C) and cooling of fluids with constant salinity (between Groups E and F), which likely correspond to the quartz-sulfide stage, and c) inflow of meteoric water (Group D—the post-ore quartz-calcite stage). [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
49. Low-pressure isobaric cooling metamorphic P–T paths from Botnnuten in the southern Lützow-Holm Complex, East Antarctica.
- Author
-
Baba, Sotaro, Ohshiro, Seira, Kamei, Atsushi, Hokada, Tomokazu, and Kitano, Ippei
- Subjects
- *
CORDIERITE , *GNEISS , *COOLING , *BASEMENTS , *MINERALS , *GARNET - Abstract
This paper reports the metamorphic texture of cordierite megacrysts and the metamorphic P–T path of a newly exposed section of gneiss in East Antarctica. We used mineral textures and pseudosection modeling to reconstruct the metamorphic P–T path of cordierite- and spinel–garnet-bearing gneisses from Botnnuten, an isolated nunatak located ~ 60 km from the southern edge of Lützow-Holm Bay in East Antarctica. The gneisses underwent low-P granulite-facies metamorphism at 5.0–6.1 kbar and 850 ± 20 °C followed by isobaric cooling. The isobaric cooling path implies long residence in the middle to shallow crustal level without rapid exhumation. This contrasts with the widely recognized clockwise P–T path of basement rocks of the Lützow-Holm Complex. The rocks at Botnnuten have long been considered part of the Lützow-Holm Complex based on their petrographical features and geothermobarometric data. However, the present results, combined with a reevaluation of available data, indicate the metamorphic history of the Botnnuten gneisses is more comparable to that of the Yamato Mountains, located southwest of the study area. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
50. Achieving hardness‐strength‐toughness synergy in (Ti, W, Mo, Cr)(C, N)‐based cermets.
- Author
-
Wang, Lu, Cao, Zhinan, Jin, Na, and Liu, Ying
- Subjects
- *
CERAMIC metals , *FLEXURAL strength , *SOLUTION strengthening , *TUNGSTEN alloys , *ELASTIC modulus , *FRACTURE toughness , *GARNET - Abstract
Ti(C, N)‐based cermets have been considered to be the most potential candidates for WC‐Co cemented carbides as tool material due to their various advantages. However, the trade‐off between hardness/strength and toughness limits their further application. Herein, we present new (Ti, W, Mo, Cr)(C, N)‐based cermets showing superior mechanical properties with hardness of 1525 MPa, transverse rupture strength of 2428 MPa, and fracture toughness of 11.44 MPa·m1/2 by compositional and interfacial modification. The strengthening and toughening mechanisms were revealed by experimental observation and theory calculation. It could be clarified that the high elastic modulus caused by a polar covalent bond in the hard phase and solid solution strengthening of the binder phase attributed to the hardness. The strong interface bonding between the core/rim, inner/outer rim, and rim/binder phases stemming from the composition optimization contributed to super crack resistance. Intergranular fracture in submicron‐scaled hard phases led to the crack deflection, transgranular fracture in the micron‐scaled hard phases consumed more energy due to their high intrinsic hardness and excellent interface coordination. The synergy of multi‐scaled hard particles brought about excellent comprehensive mechanical properties. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.