Search

The sintering of high-performance ceramics with complex shapes at low temperatures has a significant impact on the future application of ceramics. A joint process of digital light processing (DLP) 3D printing technology and a nitrogen-gas pressure-assisted sintering method were proposed to fabricate AlN ceramics in the present work. Printing parameters, including exposure energy and time, were optimized for the shaping of green bodies. The effects of sintering temperature, as well as nitrogen pressure, on the microstructure, density, and thermal conductivity of AlN ceramics were systematically discussed. A high thermal conductivity of 168 W·m−1·K−1 was achieved by sintering and holding at a significantly reduced temperature of 1720 °C with the assistance of a 0.6 MPa nitrogen-gas pressure. Further, a large-sized AlN ceramic plate and a heat sink with an internal mini-channel structure were designed and successfully fabricated by using the optimized printing and sintering parameters proposed in this study. The heat transfer performance of the ceramic heat sink was evaluated by infrared thermal imaging, showing excellent cooling abilities, which provides new opportunities for the development of ceramic heat dissipation modules with complex geometries and superior thermal management properties. [ABSTRACT FROM AUTHOR]

Eu 3+ -doped Lanthanum gadolinium hafnates (La 0.8 Gd 1.2 Hf 2 O 7 ) transparent ceramics with different Eu 3+ concentration were fabricated by vacuum sintering. XRD results showed all the ceramics are cubic pyrochlore structure. The effects of annealing process on in-line transmittance and luminescence behavior of the Eu 3+ -doped La 0.8 Gd 1.2 Hf 2 O 7 transparent ceramics were investigated. Before annealing, the in-line transmittance of the ceramics was low and the luminescence intensity was weak. As Eu 3+ doping content increased, the transmittance as well as the luminescence intensity decreased. This was ascribed to oxygen vacancy and other defects in the ceramics resulted from the vacuum sintering. After annealing, the transmittance and luminescence intensity were raised, indicating the elimination of oxygen vacancy. Moreover, with the increase of Eu 3+ doping content from 1 at% to 10 at%, the luminescence intensity increased without concentration quenching. [ABSTRACT FROM AUTHOR]

In this paper, the high-quality factor mullite microwave dielectric ceramic is employed to introduce in dielectric resonator antenna (DRA). The microwave dielectric properties of ɛr ∼ 5.8, Q × f ∼ 31 240 at 9.66 GHz, and loss tangent tanδ = 1/Q ∼ 2.7 × 10−4 can be obtained by the solid-state reaction method in mullite microwave dielectric ceramic sintered at 1700 °C. On this basis, the resonant modes of the proposed broadband high-gain rectangular DRA are analyzed by using a dielectric waveguide theoretical model and the antenna performance is evaluated by a commercial CST Microwave Studio 2021® software. It has been found that the proposed rectangular DRA can provide a broad bandwidth of 35.9%, a maximum gain of 10 dBi at 3.61 GHz, and a radiation efficiency of 90% in the range of 3.13–4.42 GHz. For demonstration, adequate consistency between the simulation results and the measurement results was achieved. The proposed DRA has great application potential and value in 5G communication scenarios requiring wideband and high-gain antenna. [ABSTRACT FROM AUTHOR]

La 2- x Gd x Hf 2 O 7 ( x =0–2.0) transparent ceramics were fabricated through vacuum sintering from nano-powders synthesized by a simple combustion method. The phase composition of the powders and final ceramics, the in-line transmittance, microstructures and density of the ceramics were investigated. With the increasing of Gd content, the ceramics maintained the cubic pyrochlore structure, and the lattice parameters decreased, whilst the densities increased linearly. All the ceramics were transparent. The highest in-line transmittance was 76.1% at 800 nm ( x =1.2). With high density (7.91–8.88 g/cm 3 ) and effective atomic number, some of the La 2- x Gd x Hf 2 O 7 ( x =0–2.0) transparent ceramics are promising candidates for scintillator hosts. [ABSTRACT FROM AUTHOR]

3 at.% Eu3+-doped La2− xGd xZr2O7 ( x = 0-2.0) transparent ceramics were fabricated by vacuum sintering. The effect of Gd content on crystal structure, in-line transmittance, and luminescence property of the ceramics were investigated. The ceramics are all cubic pyrochlore structure with high transparency. The cut-off edge of the transmittance curve of the ceramics varied with Gd content and was also affected by the annealing process. The luminescence intensity became stronger for the ceramics annealed in air. As Gd content increased, the energy band structure as well as the luminescence behavior of the ceramics was changed; in addition, the symmetry of the crystal lattice reduced, resulting in the shift of the strongest luminescence peak from 585 nm to around 630 nm. [ABSTRACT FROM AUTHOR]

Ethnopharmacological relevance The processed lateral root of Aconitum carmichaelii Debeaux (Ranunculaceae), an extensively used traditional Chinese medicine, is known as Fuzi in China (Chinese: 附子), “bushi” in Japan, “Kyeong-Po Buja” in Korea, Chinese aconite, monkshood or Chinese wolfsbane. It has been used to treat shock resulting from acute myocardial infarction, low blood pressure, coronary heart disease, chronic heart failure, etc. Aim of the review The present paper aims to provide an up-to-date review at the advancements of the investigations on the ethnopharmacology, phytochemistry, pharmacological effect and toxicity of Fuzi. Besides, the possible tendency and perspective for future research of this plant are discussed, as well. Materials and methods All available information on Fuzi was collected via electronic search (using Elsevier, PubMed, ACS, CNKI, Google Scholar, Baidu Scholar, and Web of Science), books and classic works about Chinese herb. Results 122 chemical constituents, among which C 19 -diterpenoid alkaloids and C 20 -diterpenoid alkaloids are the predominant groups, have been isolated and identified from Fuzi. Fuzi with its active compounds is possessed of wide-reaching biological activities, including effects on cardiovascular system, anti-inflammation and analgesic action, anti-tumor activity, effect on the immune system, hypoglycemic and hypolipidemic effects, anti-aging effect, effect of protecting kidney and effect on energy metabolism. Conclusions Nearly all of compounds were found from the roots of the plant, so further phytochemical studies should focus more on the other parts of the plant, such as the leaves, flowers or stems. Besides, a majority of the pharmacological studies were carried out using crude and poorly characterized extracts. Thus, more bioactive components particularly cardiotonic and analgesic compounds should be identified through bioactivity-guided isolation strategies. Moreover, investigations on how to develop Fuzi׳s new clinical usage on the basis of its pharmacological effects are in requirement. [ABSTRACT FROM AUTHOR]

The phase composition, microstructure, electrical and thermal properties of hot-pressed AlN-2 wt% Yb 2 O 3 -4 wt% Sm 2 O 3 - x wt% TiN (x = 0, 0.4, 0.8, 1, 2, 3, 4) ceramics were systematically investigated. Yb 2 O 3 and Sm 2 O 3 were used to react with Al 2 O 3 in AlN to form Yb 3 Al 5 O 12 , SmAlO 3 and SmAl 11 O 18 , which made the samples densely sintered. When sintered at higher than 1700 °C, the electrical resistivity of AlN ceramics with 2 wt% Yb 2 O 3 -4 wt% Sm 2 O 3 decreased significantly to 1010 Ω·cm. This decrease in resistivity was probably caused by the continuity of the secondary phase, which encasing the AlN grains and deteriorating the thermal conductivity. When sintered at 1650 °C, the addition of 0.4–4.0 wt% TiN reduces the electrical resistivity from 8.9 × 1012 to 2 × 1010 Ω·cm while maintaining thermal conductivity at around 90 W/m·K with high compactness. Finally, a series of high performance AlN ceramics, with adjustable electrical/thermal properties, could be obtained for modern semiconductor industry. [ABSTRACT FROM AUTHOR]

Alumina ceramics with optimized microstructures and mechanical properties were obtained by the attractive digital lighting processing (DLP) additive manufacturing methodology in the present study. A acrylate-based resin system was designed for the alumina powders with a mean particle size of 0.5 μm. The influence of oligomer on the viscosity and polymerization kinetics of the ceramic suspensions has been elaborately discussed by rheology, curing depth and photo-DSC characterizations. The results indicated that the introduction of oligomer has improved the cross-linking density of resins and decreased the critical dose of energy for resin polymerization, which contributed to a tougher ceramic-resin slice with higher dimensional accuracy. Densifying processes including debinding and high temperature sintering of the ceramic parts were conducted according to the TG-DTA characterizations, alumina ceramics with uniform microstructures and eliminated delamination or intralaminar cracks were finally obtained. The flexural strength was 471 MPa for the ceramics obtained from the resin composition containing 20 wt% oligomer, Weibull modulus for the ceramics were determined to be 17.31 by evaluating thirty all sides polished ceramics, indicating the highly uniform property of the ceramics fabricated by DLP additive manufacturing. [ABSTRACT FROM AUTHOR]

Highlights: [•] The up-conversion emission intensity of NaYF4:Yb3+, Er3+ after silica coating was significantly enhanced. [•] The up-conversion intensity ratio between red emission and green emission was decreased after silica coating. [•] The mechanism of up-conversion luminescence and emission intensity change was illuminated. [ABSTRACT FROM AUTHOR]

Highlights: [•] Combustion method and vacuum sintering were used to fabricate La2-xGdxZr2O7. [•] The lattice parameters decreased with the increase of Gd3+ concent(x). [•] The absorption edge of the transmittance curves shifted to UV region from 0.4-2.0. [•] All the ceramics have high n (2.08), making them candidate for optical lens. [•] With the increase of x, the effective atomic number and density increased. [Copyright &y& Elsevier]

Two-dimensional carbon fiber reinforced zirconia matrix composites have been fabricated by slurry infiltration and hot pressing techniques. The room temperature mechanical properties were investigated and the fracture features of composites were observed. The results showed that with the increase of temperature the relative density of as-prepared Cf/ZrO2 composites increased. But the mechanical properties of composites on fiber configuration firstly increased and then decreased. Higher mechanical properties were obtained for the composite hot-pressed at 1500°C i.e. the flexural force and fracture energy were 136.0N and 31.3kJ·m−2 respectively. SEM observation revealed fiber pull-out in the composite sintered at ≤1500°C. For the composite sintered at a higher temperature, however, chemical diffusion between fiber and ZrO2 was found by HRTEM, which indicates the formation of strong bonding. Also the reduced nonlinear region and short pullout length of fiber suggest a strong interfacial bonding between the fiber and matrix. The strong interfacial bonding and large thermal residual stress mainly contribute to the degradation of mechanical properties above 1500°C. [ABSTRACT FROM AUTHOR]

Abstract: NaYF4 co-doped with Gd3+ and Mn2+ nanocrystals were synthesized by a solvothermal route with PEI as the surfactant. X-ray diffraction analyses evidenced that the phases of synthesized NaYF4: Gd3+, Mn2+ nanocrystals were all pure cubic structure. The luminescence intensity of 20mol% Gd3+ doped NaYF4 was stronger than that of any other concentration under the 272nm excitation. The photoluminescence emission intensity of NaYF4: Gd3+, Mn2+ at 561nm was increased with the increase of Gd3+ doping concentration. The energy transfer mechanisms between Gd3+ and Mn2+ were discussed. The results showed that the energy level of 6PJ of Gd3+ ions played a key role in the energy transfer process. Furthermore, the Mn2+ ions doped NaYF4: Gd3+ nanocrystals with a strong green emission and proper paramagnetism originated from Gd3+ and Mn2+ may find potential applications in bio-probes and magnetic resonance imaging. [Copyright &y& Elsevier]

• Highly transparent and submicrometer-grained Yb:Y 2 O 3 ceramics were prepared only by hot pressing for the first time. • The mechanical properties of hot-pressed Yb:Y 2 O 3 transparent ceramics have better mechanical properties than pressureless sintered samples. • The highest transmittance of the Yb:Y 2 O 3 ceramic was 81.7% at 1100 nm and 77.2% at 600 nm, which is near the theoretical value. Highly transparent and submicrometer-grained Yb:Y 2 O 3 ceramics were obtained by hot-pressing method with ZrO 2 sintering additive. Hot-pressing method provides extra driving force to promote the densification of Yb:Y 2 O 3 transparent ceramics, resulting in high transmittance achieved. The transmittances of all samples were ranging from 80.5% to 81.8% at 1100 nm and 72.7–77.7% at 600 nm. The ceramic samples in this work were sintered at a low temperature of 1600 ℃ for 3 h, providing dense microstructures with average grain size less than 1 µm, which are smaller than those of Yb:Y 2 O 3 ceramics prepared by other traditional sintering techniques. The microhardness and fracture toughness were ranging from 8.16 to 7.99 GPa, and from 0.94 to 0.88 MPa·m1/2, respectively, which are higher than the comparison samples fabricated by pressureless sintering. The absorption cross-sections of the 1 at% Yb-doped sample at 950 and 976 nm were 0.93 × 10−20 and 1.22 × 10−20 cm2, respectively. The fluorescence decay lifetime at 1032 nm was in the range of 0.79–1.36 ms. According to the available literature, this is the first report about Yb:Y 2 O 3 transparent ceramics fabricated by hot-pressing sintering without any combined sintering process. The ceramics obtained may have potential use for solid-state lasers partly replacing single crystals. [ABSTRACT FROM AUTHOR]

Abstract: A simple combustion method was used to synthesize LaGdZr2O7 powder and LaGdZr2O7 transparent ceramic was prepared by vacuum sintering at 1850°C for 6h. The final transparent ceramic, with a density of 6.46g/cm3, has an in-line transmittance of 70.7% at 1000nm and a refractive index of 2.08 at 632.8nm. [Copyright &y& Elsevier]

Abstract: Y2Hf2O7 transparent ceramics were successfully fabricated via vacuum sintering at 1900°C for 6–12h by the solid-state reaction using the corresponding nitrate and oxide powders without additives. The fabricated transparent ceramics showed a well-defined microstructure and no pores or other defects were observed. The linear optical transmittance reached to 60% in the visible wavelength region, which is about 76% of the corresponding single crystal. The refractive index of the Y2Hf2O7 transparent ceramics was above 2.01 in the region between 400nm and 800nm. [Copyright &y& Elsevier]

Thermal management has become one of the most challenging issues for high‐power, integrated, and miniaturized electronic devices. In this paper, an alumina ceramic heat sink with mini‐channels was fabricated using a digital light processing 3D printing technology. Microstructures of the ceramic were investigated by scanning electron microscopy. A proper flow rate of water in the mini‐channels was figured out for efficient cooling by infrared thermal imaging and micro‐thermocouple characterizations. The ceramic heat sink was further integrated with a high‐power laser diode module; cooling performance was evaluated by investigating the thermal resistance of the ceramic heat sink and the optoelectronic property of the laser diode module. Results indicated that the laser diode module could be operated at high driving power of 115.6 W. This study provided a new strategy for a highly efficient thermal management of electronic devices and highlighted the technical potential of ceramic heat sink with more compact coolant channels. [ABSTRACT FROM AUTHOR]

Abstract: Transparent Er3+ doped NaYF4 upconversion films were formed on the glass substrate by a two-step process, ligand exchange and spin coating. Upconversion nanocrystals showed strong bonding ability with glass substrates and exhibited stronger emission intensity after silane ligand exchange. The spin coating rate and nano colloid concentration were varied and the resulting I–V curves of these films were measured and calculated under a standard AM0 non-concentrated condition. Immobilization of all these transparent upconversion films in the solar cell system yielded stable efficiency enhancements. Furthermore, control experiments demonstrated that upconversion was the only reason for the efficiency gains. The best improvement of the efficiency was measured to be relatively 8.6% under 100mW/cm2 radiations. [Copyright &y& Elsevier]

Abstract: High quality transparent yttrium aluminum garnet (YAG) ceramics with an average grain size of about 12μm have been fabricated by a solid state reactive sintering method. Plasma resistance property of the fabricated YAG ceramics was studied and compared with that of the Y2O3 ceramics, silicate glass and quartz. The YAG ceramics showed an excellent plasma resistance as well as Y2O3 ceramics. After etching in F-plasma for 6h, the eroded depth of YAG ceramics was about 100nm. The plasma resistance of YAG ceramics was far better than that of silicate glass and quartz. [Copyright &y& Elsevier]

Abstract: Commercial Y2O3 powder was used to fabricate highly transparent Y2O3 ceramics with the addition of ZrO2 via slip casting and vacuum sintering. The effects of ZrO2 addition on the transparency, grain size and lattice parameter of Y2O3 ceramics were studied. With addition of ZrO2 the transparency of Y2O3 ceramics increased markedly and the grain size of Y2O3 ceramics decreased markedly by cation diffusivity mechanism and the lattice parameter of Y2O3 ceramics slightly decreased. The highest transmittance (at wavelength 1100nm) of the 5.0mol% ZrO2–Y2O3 ceramic (1.0mm thick) sintered at 1860°C for 8h reached 81.7%, very close to the theoretical value of Y2O3. [Copyright &y& Elsevier]

Abstract: Spherical monodispersed, submicron-sized Er3+:Y2O3 powders were prepared via a homogeneous precipitation method using nitrates and urea as raw materials. The structure, phase evolution and morphology of Er3+:Y2O3 precursor and the calcined powders were studied by means of XRD, TG/DTA, FTIR and SEM methods. The upconversion spectra of spherical monodispersed Er3+:Y2O3 powders were excited with 980nm laser diode (LD) and measured by a spectrofluorometer. The results showed that monodispersed spherical powders with a particle size of 200–210nm were obtained after the precipitates were calcined at 800°C for 2h. The solution concentration of Er3+ and Y3+ had a significant impact on the morphologies of the precursor and powders. Low solution concentration such as 0.015M can promote precipitation precursor to keep uniform spherical shape. The resultant monodispersed Er3+:Y2O3 phosphors exhibit upconversion luminescence properties and the intensity of the upconversion luminescence reaches the maximum when the Er3+ concentration is 3at.%. [Copyright &y& Elsevier]

AbstractPurposeMethodsResultsConclusionAge-related macular degeneration (AMD) is the leading cause of blindness in the elderly, but the therapies are not satisfactory. This study aimed to find AMD specific features through the analysis of high-throughput sequencing.In this study, we integrated six projects containing single-cell RNA sequencing (scRNA-seq) data to perform a comprehensive analysis for AMD samples in the tissues of retina and retinal pigment epithelium/choroid, and in the positions of macula and periphery. Differentially expressed genes (DEGs) were analyzed and crucial signaling pathways were identified across cell types and between the macula and periphery. The intercellular signaling transduction among cell types were inferred by "CellChat" to build cell–cell communication network under normal and AMD conditions, and verified at the transcriptional level. The CD31+ endothelial cells were obtained to evaluate the enrichment of KEGG pathways in atrophic and neovascular AMD, and GSVA was adopted to discover differential metabolic signals in each AMD type.Thirteen major cell types were identified in the integrated scRNA-seq data. Although no disease-specific cell type or differential cell proportion was found, DEGs and enriched pathways were shown in cell-type- and position-dependent manners. Severe impairment of endothelial cell-mediated cell interactions was found in the signaling transduction network of the macula, and compromised cell interactions were observed in the periphery. Furthermore, distinct signaling pathways and metabolic states were uncovered in atrophic and neovascular AMD. Striking reduction in energy metabolism, lipid metabolism, and oxidative stress was indicated in the atrophic AMD.Conclusively, we discover aberrant signals and metabolic pathways in AMD samples, providing insight into mechanisms and potential therapeutic targets for the AMD treatment. [ABSTRACT FROM AUTHOR]

Low-cost amorphous nano-carbon (ANC) was employed as an absorbent to modify the microwave performance of AlN ceramics (AlN-4 wt% Y 2 O 3 - x wt% C, x = 0, 2.0, 3.8, 3.9, 4.0) via hot-pressing sintering, and the thermal and mechanical properties were also investigated. With the increase of ANC content from 0 to 4.0 wt%, the relative density of AlN composite decreases from 3.28 g cm−3 to 3.16 g cm−3 when sintered at 1800 °C for 2 h, and with the increase of sintering temperature from 1700 °C, the density of the 4.0 wt% ANC doped AlN composite presents trend of increase and reaches the maximum value of 3.16 g cm−3 at 1800 °C and then decreases. The XRD pattern shows that the composites are composed of AlN and Y–Al–O (YAG, YAP, YAM et al.) phases. SEM results indicate that average grain sizes for AlN and secondary phases gradually decrease with increasing carbon content, suggesting inhibited grain growth due to ANC addition. No obvious changes in phase constitution nor intensity changes were detected with the increase in carbon content and sintering temperature. As the carbon content increases from 0 to 4.0 wt%, the dielectric constant gradually increases from ∼9 to 13.89 at 10 GHz, the dielectric loss gradually increases from the vicinity of 10−3 to 0.38 at 10 GHz, and the reflective loss decreases from −27.92 dB to −49.40 dB, the thermal conductivity of the AlN-ANC composite decreases from 116.63 W m−1 K−1 to 50.13 W m−1 K−1. In addition, with 4.0 wt% ANC addition, the dielectric constant, dielectric loss, reflective loss, hardness, elastic modulus, bending strength, and fracture toughness are 13.89, 0.38, 49.40 dB, 6.4 ± 0.4 GPa, 262 GPa, 268.78 MPa, and 1.4 ± 0.1 MPa m1/2, respectively. Its ability to efficiently absorb microwave energy enhances the performance of devices including radar systems, communication equipment, and microwave heating systems, making it a promising candidate for microwave vacuum electronic applications. [ABSTRACT FROM AUTHOR]

Two-phase LaLuZr2 O7 transparent ceramic was fabricated via vacuum sintering using powders obtained by a simple sol-gel combustion method. These two phases are pyrochlore and defective fluorite phase with different chemical components. The in-line transmittance of LaLuZr2 O7 transparent ceramic is 73.4% at 1100 nm, showing an excellent optical performance. LaLuZr2 O7 transparent ceramic is a promising candidate for scintillator host due to its high density (6.82 g/cm3). [ABSTRACT FROM AUTHOR]

Four control experiments (S1: Y 3 Al 5 O 12 , S2: Y 3 Al 5 O 12 +1 wt%Nb 2 O 5 , S3: Y 3 Al 4.955 Nb 0.045 O 12 , S4: Y 2.955 Al 5 Nb 0.045 O 12) were designed to investigate the co-effects of Nb 2 O 5 and non-stoichiometry on the microwave dielectric properties of Y 3 Al 5 O 12. The beneficial results of Nb 2 O 5 doping are demonstrated based on X-ray patterns, electron diffraction information, Rietveld refinement, and micromorphological characterization. Differences in dielectric properties were explored using lattice defects, ion polarizability, bond valence, and Raman spectroscopy. In contrast, the Y-deficient sample (S4) possesses the best dielectric properties (ε r ∼ 10.37, Q × f ∼ 161,724 GHz and τ f ∼ -33.8 ppm/°C). [ABSTRACT FROM AUTHOR]

Highly transparent cerium‐doped yttria ceramics were fabricated via a pressureless sintering method with an addition of 10 at.% La2O3 and 1 at.% ZrO2 as a binary sintering additive. With an increase in the Ce doping concentration from 0 to 3 at.%, the optical absorption edge of yttria ceramics exhibited a significant red shift from 290 to 380 nm as a result of the 4f–5d transition of Ce3+ and the charge transfer of Ce4+ (i.e., Ce4++e–→Ce3+). For a 2‐mm thick sample doped with 3 at.% Ce, the total ultraviolet radiation (UV) transmittance (220–400 nm) is only 1.7%, indicating a nearly complete UV absorption. Meanwhile, the specimens possess high in‐line transmittance levels in both the visible and the infrared regions (i.e., >70% at 450 nm and ∼80% at 1100 nm). Additionally, the present specimens were confirmed to have good enough mechanical strength levels (∼165 MPa) and thermal conductivity (∼5 W/m·K), which are comparable or even better compared to those of previously reported transparent yttria ceramics. The results of this work indicate that cerium‐doped transparent yttria ceramics are promising candidate materials for full‐band UV‐shielding window applications. [ABSTRACT FROM AUTHOR]

Ce-doped gadolinium gallium aluminum oxide (Ce: GGAG) precursors were first prepared by the microwave-assisted homogeneous precipitation method (MAHP). Thermal gravity-differential thermal analysis (TG-DTA), X-ray diffraction (XRD), specific surface area analysis (BET) and field emission scanning electron microscopy (FE-SEM) were employed to investigate the crystal structure, phase evolution and morphologies of the Ce: GGAG precursors and powders. The influence of Ga ion concentration in the salt solution on the properties of Ce: GGAG powders was investigated. All the precursors were transformed into single-phase GGAG after being calcined at 950 °C in a furnace for 3 h. Monodispersed Ce: GGAG powders were obtained as the Ga ion concentration was lower than 0.06 mol/L. Single-phase and dense Ce: GGAG ceramics were obtained after sintering at 1600 °C in a flowing oxygen atmosphere for 10 h. Specifically, the Ce: GGAG ceramic reached its maximum density of ~6.68 g/cm3, which was close to its theoretical density of 6.70 g/cm3, and exhibited the highest optical transmittance of 65.2% at 800 nm after hot isostatic pressing sintering (HIP) as the Ga ion concentration was 0.02 mol/L. The decay time and light yield of the GGAG ceramic were 35 ns and 35,000 ± 1250 ph/MeV, respectively, suggesting that Ce: GGAG ceramics prepared using MAHP-synthesized nanopowders are promising for scintillation applications. [ABSTRACT FROM AUTHOR]

YAG:Ce/YAG:Cr/YAG:Pr composite phosphor ceramics with barcode structure were prepared by tape casting combined with the solid‐state reaction method. This structure provides a convenient and effective method for regulating the optical parameters such as luminous efficacy (LE), color rendering, and correlated color temperature (CCT) of white light‐emitting diodes/laser diodes (LEDs/LDs). For the sample with a thickness ratio of 6:6:6 for YAG:Ce, YAG:Cr, and YAG:Pr, the in‐line transmittance reaches 60% at 800 nm, and it shows a good optical performance with the LE of 106 lm/W, the color gamut (Rg) of 77, the color fidelity index (Rf) of 86, and the CCT of 7642 K. The electroluminescence spectra and color coordinates can be adjusted by changing the ratio of each component in the composite ceramic and the thickness of the ceramic because the tape casting method allows precise control of the thickness of each ceramic layer. The high tunability provides more freedom in the performance design of composite phosphor ceramics and makes them the most promising candidate for high brightness white LEDs/LDs. [ABSTRACT FROM AUTHOR]

Highly transparent Ho:Y2O3 ceramics for laser diode lighting were prepared using the vacuum sintering method with 0.3 at.% Nb2O5 as a sintering additive. The microstructures, transmittance, and luminescence properties of the Ho:Y2O3 ceramic samples were investigated in detail. The transmittance levels of all samples with various Ho3+ concentrations reached ~81.5% (2 mm thick) at 1100 nm. Under the excitation of 363 nm (ultraviolet) or 448 nm (blue) light, Ho:Y2O3 transparent ceramic samples showed that green emission peaked at 550 nm. The emission intensity was strongly affected by the concentration of Ho3+ ions, reaching its highest level in the sample doped with 1 at.% Ho3+. The CIE coordinates of the luminescence were in the green region (i.e., the CIE coordinates of the sample doped with 1 at.% Ho3+ were [0.27, 0.53] and [0.30, 0.69], under the excitation of 363 nm and 448 nm light, respectively). The possibility of its application as laser diode lighting was reported. Under the excitation of 450 nm blue laser, the sample doped with 0.5 at.% Ho3+ had the best performance: the saturated luminous flux, lumen efficiency, and the luminescence saturation power densities were 800 lm, 57.7 lm/W, and 17.6 W/mm2, respectively. Furthermore, the materials have high thermal conductivity and mechanical strength due to their host of rare-earth sesquioxide. Thus, Ho:Y2O3 transparent ceramics are expected to be a promising candidate for green-light-emitting devices for solid-state lighting, such as laser diode lighting. [ABSTRACT FROM AUTHOR]

Highly transparent yttrium titanate (Y 2 Ti 2 O 7) ceramics were fabricated by vacuum sintering using co-precipitated powders for the first time. The effects of the powder calcination temperature on the phase composition, morphology of the calcined powders, and on the microstructure and transmittance of the Y 2 Ti 2 O 7 ceramics were investigated. When the calcination temperature was above 850 °C, pure phase Y 2 Ti 2 O 7 nanopowders with high sintering activity were obtained. Transparent Y 2 Ti 2 O 7 ceramics were obtained after vacuum sintered at 1600 °C for 6 h and annealed at 1100 °C for 5 h in air. The highest transmittance reached 73% at 1000 nm when the calcination temperature was 1150 °C. The measured refractive index of Y 2 Ti 2 O 7 ceramics was higher than 2.24 at the wavelength range of 350–1000 nm, making it a promising candidate for optical devices. [ABSTRACT FROM AUTHOR]

In this study, a terbium(Ш) complex, Tb(SSA)4 (SSA = sulfosalicylate), was synthesized and employed to detect toxic chromate anion (CrO42−) as a visually identifiable probe. Luminescence investigations confirmed that the Tb complex is an excellent probe with high selectivity, high sensitivity (I0/I100 μM = 9.5), and a low detection limit (2.8 × 10−8 M), targeting CrO42− in aqueous solution. The simple fluorescence‐based probe can be quickly and easily prepared, and enables the reliable, visual detection of CrO42− ion in daily applications. [ABSTRACT FROM AUTHOR]

Three europium(III) complexes, Eu(ectfd)3 (Hectfd = 1-(9-ethyl-9H-carbazol-7-yl)-4,4,4-trifluorobutane-1,3-dione), Eu(tta)3 (Htta = 4,4,4-trifluoro-1-(thiophen-2-yl)-butane-1,3-dione), and Eu(dbt)3 (Hdbt = 2-(4',4',4'-trifluoro-1',3'-dioxobutyl)dibenzothiophene), were synthesized and employed to detect total bilirubin (BR) in blood-serum samples. UV-visible absorption and fluorescence (FL) spectroscopies were used to evaluate the selectivity of each europium (III) fluorescence probe to BR, which was shown to remarkably reduce the luminescence intensities of the europium(III) complexes at a wavelength of 612 nm. The luminescence intensity of each complex is linearly related to BR concentration. Eu(tta)3 was shown to be the more-appropriate fluorescence probe for the sensitive and reliable detection of total BR in blood serum samples than either Eu(ectfd)3 or Eu(dbt)3. This observation can be ascribed to special σ-hole bonding between Htta and BR. In addition, the optimal pH test conditions for the detection of BR in human serum by the Eu(tta)3 probe were determined. Sensitivity was shown to be dramatically affected by the pH of the medium. The experimental results reveal that pH 7.5 is optimal for this probe, which coincides with the pH of human serum. Furthermore, BR detection using the Eu(tta)3 luminescence probe is simple, practical, and relatively free of interference from coexisting substances; it has a minimum detection limit (DL) of 68 nM and is a potential candidate for the routine assessment of total BR in serum samples.ᅟ [ABSTRACT FROM AUTHOR]

Abstract 1 1 Dissolved oxygen, DO; gaseous oxygen, GO; metal-to-ligand charge transfer, MLCT; 2-thenoyltrifluoroacetonate, TTA; polystyrene, PS. A luminescent film comprising Eu (Ш)-doped yttrium oxide nanosheets was fabricated by electrophoretic deposition, modified by 2-thenoyltrifluoroacetonate, and coated with polystyrene to obtain a novel oxygen sensor capable of detecting both dissolved (DO) and gaseous (GO) oxygen based on luminescence intensity quenching. Based on the results of luminscence lifetime, the mechanism of molecular oxygen–induced luminescence quenching was discussed in detail. The above film exhibited high sensitivity and a well-linear response, with its high photostability making it a promising material for DO and GO sensing. [ABSTRACT FROM AUTHOR]

Strychnos nux-vomica L. belongs to the genus Strychnos of the family Loganiaceae and grows in Sri Lanka, India and Australia. The traditional medicinal component is its seed, called Nux vomica. This study provides a relevant and comprehensive review of S. nux-vomica L., including its botany, ethnopharmacology, phytochemistry, pharmacology and toxicology, thus providing a foundation for future studies. Up to the present day, over 84 compounds, including alkaloids, iridoid glycosides, flavonoid glycosides, triterpenoids, steroids and organic acids, among others, have been isolated and identified from S. nux-vomica. These compounds possess an array of biological activities, including effects on the nervous system, analgesic and anti-inflammatory actions, antitumor effects, inhibition of the growth of pathogenic microorganisms and regulation of immune function. Furthermore, toxicity and detoxification methods are preliminarily discussed toward the end of this review. In further research on S. nux-vomica, bioactivity-guided isolation strategies should be emphasized. Its antitumor effects should be investigated further and in vivo animal experiments should be performed alongside in vitro testing. The pharmacological activity and toxicology of strychnine -oxide and brucine -oxide should be studied to explore the detoxification mechanism associated with processing more deeply. [ABSTRACT FROM AUTHOR]

Wet foams fabricated by direct foaming for use as ceramic foams are usually fixed with extra additives. Here, we fabricated alumina ceramic foams involving only an anionic dispersant (ammonium polyacrylate, NHPA) and a cationic surfactant (dodecyltrimethylammonium chloride, DTAC) without extra additives. DTAC interacted with the NHPA adsorbed on alumina particles and changed the zeta potential and hydrophobicity of the particles. In wet foam, the partially hydrophobic particles not only acted as foam stabilizers, but also formed a 3D network, which fixed the wet foam. By optimizing NHPA and DTAC concentration, alumina ceramic foam with high porosity (79.8%), small average cell size (50 μm) and high compressive strength (30.3 MPa) was obtained. This facile method is promising to fabricate any other ceramic foam due to its universal nature. [ABSTRACT FROM AUTHOR]

Highly transparent Er:Y2O3 ceramics (1–9 at.% Er) were fabricated by hot pressing sintering with ZrO2 as the sintering additive. The microstructures, transmittance, luminescent properties, thermal conductivity, and mechanical properties of the Er:Y2O3 ceramic samples were investigated in detail. The samples all exhibited dense and fine grain microstructures; the average grain sizes were about 0.8 μm. The transmittance levels of the samples with various Er concentrations (2 mm thick) at the wavelengths of 600 and 2700 nm were ~74 and ~83%, respectively. As the Er doping concentration increased from 1 to 9 at.%, the up-conversion luminescence of the samples gradually changed from green to red, with the intensity ratio of red/green light increasing from 0.28 to 2.01. Meanwhile, the down-conversion luminescence properties of the specimens were also studied. When the samples were under 980 nm excitation, the emission bands were detected at 1552, 1573, 1639, and 1661 nm. The thermal conductivity of the samples was found to decrease from 8.72 to 5.81 W/(m·K) with an increase of the Er concentration from 1 to 9 at.%. Moreover, the microhardness and fracture toughness of the samples with 1 at.% Er concentration were ~8.51 GPa and ~1.03 MPa·m1/2, respectively. [ABSTRACT FROM AUTHOR]

Highly transparent yttria ceramics were fabricated by pressureless sintering with Nb2O5 or Ta2O5 as a novel sintering additive. The optical transmittance, microstructural evolution, and thermo‐mechanical properties of the samples were investigated. The optimal doping concentrations of Nb2O5 and Ta2O5 are 0.3 and 0.2 at.%, respectively, which are much lower compared to those of previously reported counterparts. The transmittance of the sample with 0.3 at.% Nb2O5 reaches 81.6% at 1100 nm and 72.4% at 400 nm (2 mm in thickness), similar transmittance was obtained in the sample with 0.2 at.% Ta2O5. The microhardness (∼7 GPa), fracture toughness (∼0.85 MPa·m1/2), and biaxial strength (∼200 MPa) of the present samples were confirmed to be comparable or even better compared to those of previously reported transparent yttria ceramics fabricated by pressureless sintering. Furthermore, the present samples, by virtue of the low doping concentrations, possessed relatively high thermal conductivity values (>10 W/m·K), which substantially guaranteed high thermal shock resistance. [ABSTRACT FROM AUTHOR]

In this study, Y3−xLaxAl5O12 (0 ≤ x ≤ 0.09) ceramics were synthesized, and the phase composition, lattice evolution, and microwave dielectric properties were investigated in detail. Scanning electron microscopy confirms that the addition of moderate amounts of La2O3 improves the grain development of YAG ceramics, but excessive doping destabilizes the crystal structure. Transmission electron microscopy characterization shows that the variation of the dielectric properties of the samples with x‐value is related to the occurrence of benign dislocation structures caused by modifications in the type and content of the A‐site rare‐earth ions. The variations in relative density, dielectric constant, and quality factor remain basically coordinated. The optimum microwave dielectric properties of La3+ doped YAG samples are exhibited as εr = 10.61, Q × f = 187, 542 GHz, τf = −31.2 ppm/°C when La2O3 is doped at x = 0.015. [ABSTRACT FROM AUTHOR]

In order to meet the increasing demand for high‐power laser diode lighting and displays, phosphor converters with high‐brightness and high‐directionality ought to be constructed to enhance the luminance and luminous efficacy. However, the pores formed during the sintering of phosphor ceramics affect the scattering effect and directionality of light. Therefore, porosity optimization and pore size regulation need to be explored. In this work, a series of Ce:YAG ceramics with various porosities and pore sizes were prepared. The influences of porosity and pore size on the microstructure, light confinement ability, and optical properties of Ce:YAG ceramics were studied. The ceramic phosphor with a porosity of 10 vol.% and a pore size of 3 μm exhibits a good spot confinement ability and shows a high luminous flux value of 3430 lm and a central luminance (1669 592 cd/m2) under blue laser excitation. The 10 vol.% Ce:YAG ceramic phosphor with a pore size of 5 μm has the highest emission intensity and gives a maximum luminous efficacy of 268 lm/W and a luminous flux of 4020 lm under 30 W/mm2 blue laser excitation. Thus, the porous Ce:YAG ceramics are expected to be a promising candidate for high‐brightness laser lighting and projection applications. [ABSTRACT FROM AUTHOR]

Glutathione (GSH) is generally used as an effective and sensitive tumor marker because its abnormal levels are associated with high free radical level in tumor. In this work, GSH could be easily detected by a kind of designed Eu‐based metal–organic frameworks (Eu‐MOFs, named Eu(DTBA)) fluorescent sensor. Due to the "antenna effect" of 4,4′‐dithiobenzoic acid (4,4′‐DTBA) ligands on Eu3+, Eu(DTBA) emits the strong characteristic red light of Eu3+ under ultraviolet excitation. Moreover, the emission intensity strongly depends on GSH concentrations. Thus, Eu(DTBA) can serve as a turn‐off fluorescent switch of GSH because its framework structure can easily be destroyed by GSH that leads to the fluorescence quenching. Remarkably, during sensing GSH, Eu(DTBA) has shown many appealing performances, such as broad a response window (0–20 mM), fast response (3 min), high sensitivity (LOD = 0.35 µM), and excellent anti‐interference ability. The real bioimaging application has demonstrated that the reported Eu(DTBA) can be used as an excellent bioimaging agent to successfully distinguish tumor cells from normal cells in clinical diagnosis. [ABSTRACT FROM AUTHOR]

Ethnopharmacological relevance Panax notoginseng (Burk.) F.H. Chen is a widely used traditional Chinese medicine known as Sanqi or Tianqi in China. This plant, which is distributed primarily in the southwest of China, has wide-ranging pharmacological effects and can be used to treat cardiovascular diseases, pain, inflammation and trauma as well as internal and external bleeding due to injury. Aims of the review This paper provides up-to-date information on investigations of this plant, including its botany, ethnopharmacology, phytochemistry, pharmacology and toxicology. The possible uses and perspectives for future investigation of this plant are also discussed. Materials and methods The relevant information on Panax notoginseng (Burk.) F.H. Chen was collected from numerous resources, including classic books about Chinese herbal medicine, and scientific databases, including Pubmed, SciFinder, ACS, Ebsco, Elsevier, Taylor, Wiley and CNKI. Results More than 200 chemical compounds have been isolated from Panax notoginseng (Burk.) F.H. Chen, including saponins, flavonoids and cyclopeptides. The plant has pharmacological effects on the cardiovascular system, immune system as well as anti-inflammatory, anti-atherosclerotic, haemostatic and anti -tumour activities, etc. Conclusions Panax notoginseng is a valuable traditional Chinese medical herb with multiple pharmacological effects. This review summarizes the botany, ethnopharmacology, phytochemistry, pharmacology and toxicology of P. notoginseng , and presents the constituents and their corresponding chemical structures found in P. notoginseng comprehensively for the first time. Future research into its phytochemistry of bio-active components should be performed by using bioactivity-guided isolation strategies. Further work on elucidation of the structure-function relationship among saponins, understanding of multi-target network pharmacology of P. notoginseng , as well as developing its new clinical usage and comprehensive utilize will enhance the therapeutic potentials of P. notoginseng. [ABSTRACT FROM AUTHOR]

Transparent YAG ceramics with different Ce 3+ doping concentrations and various sample thickness have been fabricated via solid-state sintering under vacuum, for the purpose of high power white light emitting diodes (WLEDs). Their phase compositions were checked by X-ray diffraction (XRD). Optical and luminescence characteristics were investigated by transmittance, absorption spectra and photoluminescence examinations. It is found that by altering the Ce 3+ concentration and sample thickness, the CIE color coordinates of the assembled LED devices can be tailored to white light region. More importantly, the color rendering index (CRI) of the LED devices got higher with decreased Ce 3+ doping concentration and sample thickness. Meanwhile, the effect of Ce 3+ concentration on the CRI was found more significant compared to that of the sample thickness. This study provides an efficient approach to tailor the luminescence properties, especially to improve the CRI of the WLEDs. [ABSTRACT FROM AUTHOR]

Submicron-sized Dy 3+ : Y 2 O 3 particles were successfully prepared via an urea homogeneous precipitation method, followed by a calcination at 800 °C. TG-DSC, FT-IR, X-ray diffraction (XRD), Field emission scanning electron microscope (FE-SEM), scanning electron microscope (SEM), photoluminescence (PL), and photoluminescence excitation (PLE) spectra were used to characterize the prepared samples. The particles were spherical shape and monodispersed. More importantly, the spherical Y 2 O 3 particles were found to have significant changes in size with varying dopant concentration of the Dy 3+ ions, ranging approximately from 550 to 840 nm. The possible growth mechanism of the particles was proposed. Under 349 nm excitation, the crystalline powders exhibited blue and yellow emissions due to the 4 F 9/2 → 6 H 15/2 and 4 F 9/2 → 6 H 13/2 transitions of Dy 3+ ions, respectively. It was further found that with proper Dy 3+ doping concentration, the luminescence color hue was tuned close to the ideal white light with color coordinates of (0.33, 0.33). The submicron-sized Dy 3+ : Y 2 O 3 phosphor is a promising candidate for the white light emitting diodes (WLEDs). [ABSTRACT FROM AUTHOR]

Highly transparent LaYZr 2 O 7 ceramic was obtained by vacuum sintering at 1800 °C for 6 h. The raw LaYZr 2 O 7 powder was synthesized by combustion method, and LaYZr 2 O 7 green body was obtained by slip casting. The in line transmittance and refractive index of the LaYZr 2 O 7 ceramic were 74.3% and 2.07 respectively at the wavelength of 633 nm. [ABSTRACT FROM AUTHOR]

A transparent yttrium alumina garnet (YAG) ceramic was successfully prepared by gelcasting a mixture of Al 2 O 3 and Y 2 O 3 powders aided by a reactive sintering process. A water-soluble epoxy resin gelling system was employed to fabricate large, sheet-like ceramic pieces. A stable slurry with 75 wt% solid loading and low viscosity was prepared. After casting, drying, and pre-sintering, vacuum sintering was performed at 1720 °C for 6 h. Homogeneous microstructures of both pre-sintered and sintered bodies were obtained. The resulting YAG ceramic (60 × 50 × 0.5 mm 3 ) with an average grain size of 10 μm had an in-line transmittance of 83.0% and 80.7% at the wavelength of 1064 nm and 400 nm, respectively. [ABSTRACT FROM AUTHOR]

Nb-doped and Y-deficient yttrium aluminum garnet ceramics were designed and synthesized using the solid-state reaction method according to the chemical equation Y 3−x Al 5 Nb x O 12+x (0 ≤ x ≤ 0.16). The phase composition, sintering behavior, microstructure, and microwave dielectric properties were investigated as functions of the composition and sintering temperature. A single-phase solid solution of yttrium aluminum garnet structure formation was observed in the range of 0 ≤ x ≤ 0.1. Further increments in x prompted the precipitation of the YNbO 4 secondary phase at the grain boundary of Y 3 Al 5 O 12. The complexity of the phase composition degrades the micromorphology and dielectric properties of the ceramics to varying degrees. Transmission electron microscopy results show that the lattice exhibits additional symmetry, which is closely related to the ultrahigh Q×f values of the ceramics. Effectively improving the sintering behaviour and suppressing the secondary phase by simultaneously doping with Nb5+ and reducing the yttrium stoichiometry. Finally, excellent microwave dielectric properties of ε r ~ 10.99, Q×f ~ 280,387 GHz (13.5 GHz), and τ f ~ − 34.7 ppm/°C can be obtained in x = 0.1 (Y 2.9 Al 5 Nb 0.1 O 12.1) sintered at 1700 °C for 6 h. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced fused silica composites exhibit the advantages of excellent mechanical properties, high heat resistance, low thermal expansion and low density, but low impact resistance or toughness. A novel modified slurry impregnation and hot pressing (SIHP) method was adopted to fabricate a new type of three dimensional orthogonal woven structure carbon fiber reinforced silica ceramic matrix composites (3D Cf/SiO 2 CMCs) with higher density and lower porosity. Physical characterization, flexural behavior, impact performance and toughening mechanism of the composites were investigated by three-point bending tests, impact tests, and scanning electron microscopy analysis. The 3D Cf/SiO 2 CMC showed a higher flexural strength in both warp (201.6%) and weft (263.6%) directions than those of pure SiO 2 and failed at a non-brittle mode due to the fiber debonding and pullout, and a delaminated failure of the 3D preform. The maximum impact energy absorption of the 3D Cf/SiO 2 CMC was 96.9 kJ/m 2 , almost 4 times as much as those for typical other carbon fiber reinforced CMCs. [ABSTRACT FROM AUTHOR]

Infectious endophthalmitis is an important cause of vision loss worldwide. It is an inflammatory reaction caused by bacteria, fungi, and other micro-organisms and often occurs as a complication of intraocular surgery, especially following cataract surgery or intravitreal injection. The focus of the prevention and treatment of infectious endophthalmitis is the early detection of microbial flora, such as fungi or bacteria. Current identification methods for bacteria include Gram staining-based, culture-based, and polymerase chain reaction (PCR)-based methods. The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry technology is now the standard identification method of bacteria and fungi after their isolation in culture. The remarkable sensitivity of PCR technology for the direct detection of micro-organisms in clinical samples makes it particularly useful in culture-positive and culture-negative endophthalmitis. Furthermore, PCR increases the rate of microorganism detection in intraocular samples by 20% and can provide a microbiology diagnosis in approximately 44.7–100% of the culture-negative cases. This review aims to introduce the development of different methods for the detection and identification of micro-organisms causing endophthalmitis through a literature review; introduce the research status of the first, second, and third-generation sequencing technologies in infectious endophthalmitis; and understand the research status of endophthalmitis microbial flora. For slow-growing and rare micro-organisms, high-throughput sequencing (HTS) offers advantages over conventional methods and provides a basis for the identification of pathogens in endophthalmitis cases with negative culture. It is a reliable platform for the identification of pathogenic bacteria of infectious endophthalmitis in the future and provides a reference for the clinical diagnosis and treatment of infectious endophthalmitis. The application of HTS technology may also be transformative for clinical microbiology and represents an exciting future direction for the epidemiology of ocular infections. [ABSTRACT FROM AUTHOR]

Abstract: Persistent luminescence phosphors, Tb3+, Sr2+ co-doped Lu2O3 ceramics were fabricated under vacuum at 1870°C. A strong green color afterglow could be observed after excitation with 254nm UV radiation. The afterglow was found to be roughly doubled in intensity upon stimulation with violet or blue-green photons (∼400–600nm) as well as upon IR radiation (∼800–980nm). Hence, the enhancement of the green afterglow could also be attained by means of natural sunlight. Short wavelength UV radiation was found to induce an extrinsic absorption band below about 600nm and extending into the deep UV. This was mirrored by a simultaneous decrease of the absorption by Tb3+ around 230–320nm. The extrinsic absorption seemed to contain at least two overlapping components which supposedly resulted from a band related to Tb4+/Tb3+-h and a feature resulting from F/F+ centers created upon irradiation with short UV. This absorption was shown to be reversible, as it disappeared after a short heat treatment at about 300°C as well as with continuous irradiation of ∼400nm radiation. [Copyright &y& Elsevier]

Abstract: Transparent alumina ceramics with oriented grains were successfully prepared by slip casting under an assisted magnetic field and sintering at 1850°C for 5h in vacuum. In-line transmittance of the alumina ceramic shaped under 12T reaches as high as 70.3% at 600nm. Detailed crystal plane evolution of grain oriented alumina ceramics with the assistance of different magnitude magnetic field was studied by XRD characterization. The results indicate that complete textured structure could only be realized with a magnetic field strength above 12T. Furthermore, the grain microstructure was observed by optical microscope in different directions. [Copyright &y& Elsevier]

Abstract: Highly transparent Er:YAG ceramics with different Er doping concentrations were fabricated by a reactive sintering method under vacuum. The optical properties and the microstructures of the Er:YAG ceramics were investigated. For 3mm thickness samples, the in-line transmittances of the as-fabricated Er:YAG ceramics at the wavelength of 1100nm and 400nm were about 84% and 82%, respectively. The micrograph of the Er:YAG transparent ceramics exhibited a pore-free structure and the average grain size was about 10μm. The grain boundary of the ceramics was clean and no secondary phase was detected. The absorption and emission spectra, the fluorescence decay traces of the Er:YAG ceramics were measured and discussed. The ceramics obtained may have potential use for eye-safe solid-state lasers partly replacing Er:YAG single crystals. [Copyright &y& Elsevier]