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In this study, surface mechanical attrition treatment was employed to sucessfully produce a gradient nanostructured layer on WE43 magnesium alloy. X-ray diffraction, energy dispersive X-ray spectrometer, and high-resolution transmission electron microscope observations were mainly performed to uncover the microstructure evolution responsible for the refinement mechanisms. It reveals that the grain refinement process consists of three transition stages along the depth direction from the core matrix to the topmost surface layer, i.e., dislocation cells and pile-ups, ultrafine subgrains, and randomly orientated nanograins with the grain size of ~40 nm. Noticeably, the original Mg3RE second phase is also experienced refinement and then re-dissolved into the α-Mg matrix phase, forming a supersaturated solid solution nanostructured α-Mg phase in the gradient refined layer. Due to the cooperative effects of grain refinement hardening, dislocation hardening, and supersaturated solid-solution hardening, the gradient nanostructured WE43 alloy contributes to the ultimate tensile strength of ~435 MPa and ductility of ~11.0%, showing an extraordinary strain hardening and mechanical properties among the reported severe plastic deformation-processed Mg alloys. This work provides a new strategy for the optimization of mechanical properties of Mg alloys via combining the gradient structure and supersaturated solid solution.

Tremendous volume expansion of silicon anode during cycling limits its further application. Here, a novel silicon nano-ribbon (SiNR) with (110) crystal plane is proposed as anode for the Lithium-ion batteries. The SiNRs with (110) crystal plane have been synthesized by a simple electrochemical micromachining method. Both invasion direction of the lithium-ions and expansion directions of the lithiated silicon are limited to the crystal direction. Recrystallization of SiNR induced by the retention of silicon atomic chains after delithiation is verified experimentally and theoretically. Such SiNR, without necessary surface coating treatment, exhibits high ionic conductivity, high stable solid electrolyte interphase (SEI) and long cycling stability, retaining a specific capacity of 1721.3 mAh g−1 (∼80% capacity retention) after 2000 cycles with an initial coulombic efficiency (CE) of 83%. The rational design of nanostructured battery materials and electrodes in this work also opens a new dimension in material design for other batteries.

The copper/graphene (Cu/Gr) composites made of Gr/Cu/Gr foils with a thickness of 25 μm were prepared using spark plasma sintering diffusion bonding (SPS) and hot press diffusion bonding (HP) in an Ar atmosphere at 900 °C for 20 min under a pressure of 50 MPa. The electrical conductivity of the prepared Cu/Gr composites was measured by the van der Pauw method, the microstructure was characterized using Raman spectroscopy, scanning electron microscope and transmission electron microscope, and the corresponding mechanism was analyzed by employing the first-principles calculations. The result indicates that, SPS process reduces the interfacial impurities of Cu/Gr composites, rendering a much higher electrical conductivity (108.6% IACS) than that prepared by using HP (98.8% IACS). This finding is correlated to the reduced oxygen (O) impurities on Gr/Gr interface, which is attributed to the high temperature plasma sputtering effect of SPS. In the prepared Cu/Gr composites, the impurity-free Gr/Gr interface has an ideal spacing of ∼3.3 A wherein carbon (C) across the interface do not bond. Despite the generated C–C covalent bonding within the same Gr layer bounds some of the electrons, the remaining electrons of the p orbital on each C atom are free electrons, leading to the excellent electrical conductivity. In contrast, absorption of O impurities on the Gr/Gr interface increases the spacing between the Gr layers to ∼3.8 A, and generates covalent C–O–C bonding across the interface due to p orbital hybridization. This reduces the free electron concentration and the corresponding electrical conductivity.

Riblets inspired by shark skin exhibit a great air drag reduction potential in many industries, such as the aircraft, energy, and transportation industries. Many studies have reported that blade riblets attain the highest air drag reduction ability, with a current limit of ∼11%. Here, we propose multilayer hierarchical riblets (MLHRs) to further improve the air drag reduction ability. MLHRs were fabricated via a three-layer hybrid mask lithography method, and the air drag reduction ability was studied in a closed air channel. The experimental results indicated that the maximum air drag reduction achieved with MLHRs in the closed channel was 16.67%, which represents a 52% higher reduction than the highest previously reported. Conceptual models were proposed to explain the experiments from a microscopic perspective. MLHRs enhanced the stability of lifting and pinning vortices, while vortices gradually decelerated further, reducing the momentum exchange occurring near the wall. This verified that MLHRs overcome the current air drag reduction limit of riblets. The conceptual models lay a foundation to further improve the air drag reduction ability of riblets.

In this study, the powdery solid waste fly ash cenospheres (FACs) was used to synthesize zeolite nano-ABW, which maintained the initial hollow microsphere shape of the FACs. The synthetic nano-ABW zeolite was applied to remove direct fast bordeaux (DFB) dye. The coupling effects of adsorption and photocatalysis (adsorption/photocatalysis) were investigated in the degradation process. The removal rate was effectively increased from 1.4% of FACs to 72% of ABW, which may be due to the broad pore structure of synthesized hollow zeolite ABW, providing more active adsorption sites. Moreover, nano-Co3O4 semiconductor was supported on hollow ABW to further improve degradation efficiency. The results demonstrated that the removal of DFB over 6Co3O4/ABW zeolite was 66% under dark conditions, while enhanced to 90% under sunlight. Moreover, the removal rate of DFB only dropped by 4.5% after 5 cycles. It indicated that the Co3O4/ABW catalysts have high stability, and the photocatalysis enabled to degrade the dyes adsorbed on catalysts, thereby restoring the adsorption capacity of catalysts.

In this study, Ni/W–TiN composites were fabricated by the pulse current electrodeposition (PCE) method. The effects of TiN concentration on the microstructure, microhardness, and wear properties of the resulting composites were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), microhardness tester, and friction wear testing. Among the four obtained composites, Ni/W–TiN composite prepared at 8 g/L showed the densest and finest surface structure. The TiN contents in obtained Ni/W–TiN composites at 8 and 16 g/L were estimated to 8.1 and 5.4 wt%, respectively. The average Ni/W grain diameter in Ni/W–TiN composite obtained at 8 g/L TiN was recorded as 84.7 nm. The protrusion and depression heights of the composite deposited at 8 g/L were 81.8 and 45.4 nm, respectively. This composite also processed an average microhardness of 897.6 HV, with only a few shallow and narrow scratches on its worn surface, demonstrating its prominent wear resistance when compared to the other three composites.

The effect of interstitial impurities (H and S) on the atomic, electronic structure, and mechanical properties of the γ-Fe Σ5 (021) grain boundary (GB) was investigated via first-principles calculations. H atoms act as an intergranular embrittler in the Σ5 GB due to a reduction in the charge density between the Fe atoms connected to the grains, whereas H and S co-segregation produces more pronounced embrittlement behavior, resulting in intergranular fracture. The S-induced embrittlement plays a crucial role in the H and S segregation, due to a combination of the structural and chemical effects. The fracturing of Σ5 GB due to S and H segregation is a two-step process. The first step is the breaking of Fe–Fe bonds in the GB, followed by the breaking of the remaining Fe–S bonds in the second step, resulting in the complete separation of the two grains. Moreover, the S atom can slightly compensate for the embrittlement induced by H, because some of the Fe atoms that obtain electrons from the S atoms can provide more electrons to the H atoms, and thus, they can compensate for the electrons that must be acquired from other Fe atoms. We call this “the electrons compensating effect” and this effect is helpful in the design and alloying of steels that are resistant to H embrittlement.

Well recent study confirmed that surface Bronsted acid sites could evidently improve the formation of free hydroxyl radicals of semiconductors and thus enhanced the photocatalytic degradation activ...

Sodium-ion batteries (SIBs), being an attractive candidate of lithium-ion batteries, have attracted widespread attention as a result of sufficient sodium resource with low price and their comparable suitability in the field of energy storage. However, one of the main challenges for their wide-scale application is to develop suitable anode materials with excellent electrochemical performance. Herein, a novel orderly layered VMoS2 (OL-VMS) anode material was synthesized through a facile hydrothermal self-assembly approach followed by a heating procedure. As the anode material of the SIBs, the unique structure of OL-VMS not only facilitated the rapid migration of sodium ions between the stacked layers but also provided a stable framework for the volume change in the process of intercalation/deintercalation. In addition, vanadium mediating in the framework caused more defects to produce abundant storage sites for Na+. As such, the obtained OL-VMS-based anode exhibited high reversible capacities of 602.9 mAh g-1 at 0.2 mA g-1 and 534 mAh g-1 even after 190-cycle operation at 2 A g-1. Furthermore, the OL-VMS-based anode delivered an outstanding specific capacity of 626.4 mAh g-1 after 100-cycle testing at 2 A g-1 in a voltage range from 0.01 to 3 V. In particular, even in the absence of conductive carbon, it still showed an excellent specific capacity of 260 mAh g-1 at 1 A g-1 after 130 cycles in a 0.3-3 V voltage range, which should contribute to the cost reduction and energy density increase.

In this study, Ni–SiC composite coatings with improved wear and corrosion resistance were obtained by ultrasonic electrodeposition (UED) method. The microstructure, microhardness, corrosion and abrasion resistance, and sectional composition distribution of the composite coatings were investigated by atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), electrochemical workstation, Vickers microhardness testing, and wear testing. AFM and HRTEM results revealed compact surface structure of Ni–SiC composite coating prepared by UED. Mean diameter of Ni crystals was 68.4 nm, whereas that of SiC nanoparticles present within the composite was 26.7 nm. According to XPS data, contents of Si in UED deposited Ni–SiC composite coating were approximately 23.7 at.%, whereas that of Ni was about 46.8 at.%. Ni–SiC composite coating deposited via UED method exhibited largest microhardness (715.7 HV) compared to other coatings, whereas nickel coating had mean microhardness of 485.8 HV. Icorr and Ecorr values of Ni–SiC composite coatings deposited via UED were 1.13 × 10−3 mA/cm2 and −0.311 V, respectively, indicating optimal level of corrosion resistance. Besides, surface morphological analysis of the coating revealed it to be glossy with only minor surface scratches, exhibiting the best wear resistance.

Due to the temperature and concentration determine the kinetic undercooling of interface growth and nucleation undercooling inside the melt, they play an important role in the solidification microstructure of the alloy. In this paper, the effect of temperature gradient and cooling rate on the dynamic undercooling was studied and the mechanism of the concentration at the solid-liquid interface on the kinetic undercooling during the continuous cooling process was analyzed. A calculation method for the coupling of temperature and concentration during Inconel 718 alloy solidification was developed, which can solve the problem that the concentration and temperature are difficult to be calculated at the same time in the numerical calculation.

The electrochemical performance of the Ni0.8Co0.15Al0.05LiO2 (NCAL) cathode was investigated by comparing it with the traditional La0.4Sr0.6Co0.2Fe0.8O3-δ (LSCF) and LSCF/Ce0.9Gd0.1O2-δ (GDC) cathodes with a GDC electrolyte-supported solid oxide fuel cell (SOFC). It is found that the electrochemical performance of the cells with the NCAL and NCAL/GDC cathode is better than that of the cells with the LSCF and LSCF/GDC cathode at 550 °C. The results of the electrochemical performance tests of the cells with different NCAL/GDC mass ratios (10/0, 9/1, 8/2, 7/3 and 6/4) show that the NCAL/GDC composite cathode with the mass ratio of 8/2 has the best electrochemical performance. XRD results show that when the sintering temperature is higher than 700 °C, the NCAL/GDC composite will undergo chemical reactions and generate new phases, reducing the performance of the composite cathode. XPS results show that a small amount of Li2CO3 was formed on the surface of NCAL during cathode preparation, forming a special interface between NCAL, Li2CO3 and GDC. At the NCAL-Li2CO3/GDC interfaces, due to the migration and aggregation of Li+ to the interface, a space charge region may be formed in which the Li+ enrichment may lead to the formation of the region with a high oxygen vacancy concentration. A very high oxygen vacancy concentration at the NCAL-Li2CO3/GDC interfaces will provide sufficient oxygen ion conductivity for oxygen reduction reaction (ORR) and reduce the activation energy of the reaction. NCAL will be a potential cathode material that can reduce the operating temperature of the traditional SOFC to 550 °C or lower.

The effects of Li2CO3 and LiOH on the ionic conductivity of BaCe0.9Y0.1O3(BCY)-x%Li2CO3 (x = 0, 5, 10 and 30) and BCY-y%LiOH (y = 0, 2, 5 and 8) composite electrolytes were investigated. Symmetrical cells with the structure of foam Ni–Ni0.8Co0.15Al0.05LiO2 (NCAL)∖BCY-x%Li2CO3 or y%LiOH∖foam Ni-NCAL and Pt∖BCY-x%Li2CO3 or y%LiOH∖Pt were prepared with NCAL-coated foam Ni and porous Pt as symmetrical electrodes, respectively. The ionic conductivity test results of the cells with Pt as the symmetrical electrode showed that the addition of LiOH did not improve the ionic conductivity of the BCY electrolyte, while the addition of Li2CO3 could significantly improve the ionic conductivity of the BCY electrolyte. The maximum power density of the cells with the structure of foam Ni-NCAL∖BCY-x%Li2CO3 or y%LiOH∖foam Ni-NCAL decreases with the increase in the amount of Li2CO3 or LiOH, which indicates that adding Li2CO3 or LiOH to BCY via mechanical mixing did not improve the electrochemical performance of the cells with NCAL as the electrode, and the NCAL electrode has the greatest impact on the performance of the cells. The interface of Li2CO3 and BCY should be a high-speed channel for ion conduction. Increasing the effective area of the interface between BCY and Li2CO3 and optimizing its continuity in the electrolyte should be the main development direction for improving the ionic conductivity.

The hydrogen induced intergranular crack is most common in hydrogen embrittlement phenomenon. Hydrogen atoms will preferentially diffuse into grain boundaries and then accumulate in them. Therefore, it is necessary to reveal the diffusion mechanism of hydrogen atoms at grain boundaries, which is helpful for deeply understanding hydrogen embrittlement. In this work, we performed first-principles calculations to investigate the trapping sites and diffusion behaviours of hydrogen atoms at Σ3 [ 1 ¯ 10] (111), Σ5 [ 1 ¯ 00] (021) and Σ9 [110] (2 2 ¯ 1) grain boundary structures of γ-Fe. Hydrogen atoms have no tendency to be segregated from the bulk to the Σ3 GB but hydrogen atoms tend to segregate into the Σ5 and Σ9 GBs. The solution energy of hydrogen in grain boundaries is mainly the consequence of the chemical bonding between Fe atoms in GBs and the hydrogen atom. In addition, according to the hydrogen diffusion behaviour in grain boundaries, Σ3 and Σ5 GBs act as three-dimensional barriers for hydrogen migration while the Σ9 GB acts as a one-dimensional barrier for H diffusion. Significantly, the difficulty of hydrogen diffusion along grain boundary mainly depends on the connectivity of low electron density region along grain boundary. This conclusion can provide a deep understanding of hydrogen distributions at different grain boundaries in metal materials, which is helpful for hydrogen embrittlement resistant materials design on the basis of grain boundary regulation.

Ni-SiC composite coatings with good wear and corrosion resistance could be obtained by the ultrasonic electrodeposition (UED) method in this study. The microstructure, microhardness, corrosion and abrasion resistance, and sectional composition distribution of the composite coatings were investigated employing atomic force microscopy (AFM), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), electrochemical workstation, Vickers microhardness testing, and wear testing. In addition, the statistical distributions of Ni grains in Ni coating and Ni-SiC composites were counted by using a “Nano Measurer” software. The outcome of AFM and HRTEM revealed a compact surface structure of Ni-SiC composite coating made by the UED. The mean diameter of Ni crystals was 68.4 nm, whereas that of SiC nanoparticles present within the composite was 26.7 nm. According to the XPS data, the content of Si in the Ni-SiC composite coating prepared via UED was approximately 23.7 at.% whereas that of Ni was about 46.8 at.%. The Ni-SiC composite coating deposited via UED method was found to have the largest value for microhardness (715.7 HV) compared to other coatings, although the nickel coating had a mean microhardness of 485.8 HV only. The Icorr and Ecorr values of the Ni-SiC composite coating deposited via UED were 1.13 × 10−3 mA/cm2 and − 0.311 V, respectively, indicating an optimal level corrosion resistance. Besides, the surface morphological analysis of the coating revealed that it was glossy with only minor surface scratches, and it exhibited the best resistance to wear.

Expanding the family of lanthanide terpyridine coordination polymers has yielded eighteen new complexes with two different phases, Ln(TPC)2(HCOO)(H2O) (Ln-1) and Ln(TPC)(HCOO)2 (Ln-2) (Ln = Sm–Lu, except Tm). Both structures are composed of lanthanide cations interconnected by 2,2′:6′,2′′-terpyridine-4′-carboxylate ligands to yield one-dimensional chain topologies. However, the incorporation of an additional crystallographically unique decorative TPC ligand into Ln-1 gives rises to a distinct phase. The encapsulation of both metal- and ligand-based phosphors within single coordination polymers leads to dual-emission of the afforded materials. Furthermore, judicious lanthanide doping in heterometallic Ln-1 and Ln-2 allows for fine-tuning the photoluminescent colours over a wide range of gamut. Such a combination showcases the capability to fine-tune the emission colours from deep green, to red, and to blue. In addition, direct white-light emission upon UV excitation can be achieved in the SmxGd1−x-1 system.

Ag-alloyed Cu2ZnSn(S,Se)4 kesterite semiconductors have been attracting considerable attention recently because doping with Ag can suppress the CuZn related anti-site defects, which is the main factor that limits the efficiency of kesterite solar cells. Although the performance of the thin film and the device is enhanced (for example, better crystallinity, fewer deep level defects and longer lifetime of the minority carrier) by doping a small amount of Ag in the CZTS thin film, the density of the defects remains high, and the band alignment of CdS/CZTS is not fully optimized, and the interface carrier concentration is greatly decreased. These phenomena will limit any further improvement in efficiency. In this work, to further increase the performance of the device, the interface of CdS/CZTS for an Ag-alloyed CZTS thin film solar cell was doped with In or Al. Then the properties of the thin film, interface band structure and device performance were investigated. After doping the interface with In or Al, the concentrations of the n-type and p-type carriers at the CdS/CAZTS heterojunction were boosted, and the interface band alignment was optimized, resulting in over 11% efficiency for an Ag-alloyed CZTS (with Al interface doping) thin film solar cell. Moreover, low-cost Al-doped ZnO (AZO) was used to replace indium tin oxide (ITO) as the front electrode after optimization, and more than 10% efficiency of CAZTS device without In was obtained. This study demonstrates the feasibility of controlling the doping of the interface to improve the interface performance of a heterojunction by using a simple spin coating process, and also provided a suitable experimental basis for future low-cost thin film solar cells.

We investigate multiwavelength-pumped optical frequency combs (OFCs) based on a new kind of coupling systems - a biconical microfiber coupler (MFC) combined with a fiber laser. Compared with other comb generations, this device possesses the advantages of an easy implementation and of achieving tunable pump wavelengths, which would increase the flexibility of the OFC generation. In essence, the adjustable cascaded four-wave mixing (FWM) process at the beginning stage of the frequency comb generation arouses different forms of OFCs. The proposed MFC coupling system holds promising applications in optical filtering, sensing, mode-switching and frequency combs.

The combination of microstructures and nanostructures has broad application prospects. However, most existing methods are oriented to fabricating microstructures and nanostructures separately, and the fabrication of nanostructures on a microstructured surface at the wafer level is rarely studied. In this work, a new method of fabricating large-area high aspect ratio nano-cylinders on micro-pillars based on a colloidal crystal mask is proposed. An experimental device for stripping and draining was designed to create a polystyrene colloidal crystal mask. Together with reactive-ion etching and metal-assisted chemical etching, high aspect ratio nano-cylinders on micro-pillars with controllable size were obtained on a 4-inch silicon wafer. Wetting tests were performed on four groups of fabricated structures of different sizes, and the results showed that all samples were superhydrophobic. Thus, a method for fabricating uniform, size-controllable, large-area high aspect ratio nano-cylinders on micro-pillars with great potential as a superhydrophobic engineering material is proposed.

Plant-derived polyphenol coating offers a promising route to fabricate functional surfaces for different substrate materials. However, almost all of the deposition approaches are time-consuming and involve inefficient processes, and the mechanisms behind the coating deposition are rarely understood. Herein, we report a rational methodology to achieve the rapid deposition of poly(caffeic acid) (PCA) by using H2O2 as a trigger under the assistance of copper sulfate (CuSO4). The comparative monomer structure of PCA oxidation polymerization has illustrated a significant distinction in the reaction path for PCA coating deposition which has never been reported before. Until now, the unprecedented fast velocity for polyphenol coating has been obtained, and the PCA coating exhibits excellent homogeneity, spatiotemporal tunability, and firm stability. Moreover, three different types of filtration membranes, poly(vinylidene fluoride) microfiltration membrane (PVDF MF membrane), poly(ether sulfone) (PES) ultrafiltration (UF) hollow fiber membrane, and PCA-coated PES nanofiltration (NF) membrane, are all successfully dip-coated using H2O2-triggered PCA coating. Without synthetic complexities and intricate procedures, the formation of hydrophilic and homogeneous PCA aggregates on the surface and/or inside pore walls resulted in various membranes. The as-prepared PCA-coated PVDF MF membrane demonstrates excellent oil/water separation efficiency of less than 150 ppm and a flux recovery rate of approximately 90% even after five cycles. By one-step co-deposition of PCA and poly(2-ethyl-2-oxazoline) (PEtOx) on the PES UF membrane surface, hydrophilicity and biofouling resistance are implemented for efficient protein filtration. The PES NF membrane formed by the PCA layer exhibits high mono-/divalent ion selectivity and excellent chlorine resistance. Overall, these results represent a rapid and sustainable approach to tailor PCA coatings for versatile liquid separation processes.

Silk fibroin (SF) and polyhydroxyalkanoate (PHA) have received increasing attention in recent years because of their unique biodegradability and biocompatibility. Studies on SF or PHA-based materials that are intended for use as biomaterials have attracted great attention, but few studies have been conducted on SF/PHA composite materials. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) copolymers with varying ratios of the 3-hydroxyvalerate (HV) component are the most widely used member of PHAs. In this study, SF/PHBV composite nanofibers were prepared by electrospinning. The stability of the mixed solution of SF/PHBV was explored first. Fourier transform infrared (FTIR) spectroscopy was used to study the composition of the precipitates caused by mixing the SF solution with the PHBV solution. The morphology of the electrospun SF/PHBV composite nanofibers was observed by scanning electron microscopy (SEM). The average diameters of the pure PHBV, pure SF, SF/PHBV (the content ratio of solute SF/PHBV (w/w) was 10/1), and SF/PHBV (the content ratio of solute SF/PHBV (w/w) was 4/1) nanofibers were 495.12 ± 82.27, 67.88 ± 14.52, 171.10 ± 40.38, and 149.70 ± 28.57 nm, respectively. To discuss the influence of the electrospinning parameters on the spinning stability and morphology of the electrospun SF/PHBV (10/1) composite nanofibers, a univariate analysis experiment was designed. When the applied voltage was 15 kV, the feeding rate was 0.3 mL/h, and the tip-to-collector distance was 13 cm, the spinning stability, uniformity and formability of the SF/PHBV (10/1) composite nanofibers were excellent. In addition to FTIR analysis, X-ray diffraction (XRD) was also used to explore the structure of the electrospun SF/PHBV composite nanofibers. As the content of PHBV increased, the crystallinity of the SF/PHBV composite nanofibers could be improved. The thermogravimetric analysis (TGA) results indicated that the thermal stability of SF was better than that of PHBV. As the content of PHBV increased, the thermal stability of the SF/PHBV composite nanofibers would decrease.

Yttria-modified silicide (MoSi2-Y2O3) oxidation-resistant coatings with multiple Y2O3 contents were prepared using supersonic atmospheric plasma spraying, and the oxidation resistance was investigated at 1700 °C with static atmosphere. Experimental results indicated that the sprayed MoSi2-Y2O3 coating possessed good compactness, which adhered well to the SiC transition layer. Meanwhile, the Y2O3 addition greatly enhanced the bonding strength of the coating, and extended its service life at 1700 °C. Wherein the MoSi2-20 wt.%Y2O3 coating exhibited the highest adhesive strength and best oxidation resistance with the lowest mass loss among all the coatings. In practice, the Y2O3 changed the microstructures of formed oxide glass scale during oxidation, and then modified the oxidation resistance of the coating. The action mechanism of Y2O3 on the oxidation behavior of MoSi2-Y2O3 coating was analyzed.

The cycling performance of batteries is largely determined by the electrode-electrolyte interphase associated with the chemical and electrochemical properties of electrolyte salts and solvents. In ...

Over the past few decades, seeding strategies for solution crystallization processes have been developed for various applications, and significant improvements in crystal quality and process robust...

This study proposed a novel electroconductive carbon fiber/circulating fluidized bed fly ash based-geopolymer (CF/CFBFAG) composite, which possessed adjustable electrical conductivity and showed a ...

A solid oxide fuel cell with 1.2 mm thick nanocrystalline BCY (BaCe0.9Y0.1O3) electrolyte was prepared by the copressing method, and its electrochemical performance was tested in H2/air conditions. The maximum power density of the nanocrystalline electrolyte cell prepared with BCY powders calcined at 1000 °C and operated at 550 °C in H2 is 405.2 mW cm−2. The carriers of nanocrystalline BCY electrolyte were studied by using double-layer electrolyte cells with pure oxygen ion conductor GDC (Gd0.1Ce0.9O2) and proton conductor SCY (SrCe0.95Y0.05O3), sintered at high temperatures as proton and oxygen ion filters. It is found that nanocrystalline BCY is a mixed conductor of oxygen ions and protons. The results of hydrogen and oxygen concentration cells show that the transference number of oxygen ions in the nanocrystalline BCY prepared in this study is higher than that of protons. XPS and HRTEM results of BCY particles before and after performance testing showed that an amorphous layer containing a high concentration of oxygen vacancies and suspected carbonate was formed on the surface of BCY particles after fuel cell performance testing. We believe that the amorphous layer should be a high-speed ion conduction channel for nanocrystalline BCY electrolyte during performance testing.

To develop a new way of renewable utilization of ground granular blast furnace slag (GGBFS), a novel ZnO-loaded graphene-reinforced alkali-activated slag-based geopolymer (ZnO/GASG) nanocomposite was originally prepared. The photocatalytic performance of ZnO/GASG was evaluated by solar hydrogen production and wastewater treatment of dyeing pollutant. The mechanical strength results indicated that the lamellate graphene inserted in the substrate of alkali-activated slag-based geopolymer (ASG) has played a critical role in crack-arresting extension so as to lead the significant increases of compressive and flexural strengthens of GASG test block. The XRD, FESEM and XPS results revealed that ZnO in the form of amorphous state dispersed on the surface of GASG when the loading approached to 2 wt%, and ZnO existed in the form of zincite when the loading was greater than 10 wt%. UV–vis diffuse reflectance spectra demonstrated that the absorption edge all of ZnO/GASG nanocomposites were blue-shifted due to the quantum size effect. The highest photocatalytic activities for H2 production (2281.3 μmol/g) and wastewater degradation (95.7%, solar light) over 15ZnO/GASG composite were ascribed to the efficient separation of photoinduced electron-hole pairs. The hole and hydroxyl radical play significant role in photocatalytic degradation of dyeing pollutant.

Solid wastes exhibit excellent prospects in the removal of heavy metals from contaminated water. However, raw solid waste materials usually show mediocre uptake efficiency, it is imperative to func...

This study aims at addressing a problem on icing detection for Unmanned Aerial Vehicle (UAV for short) because traditional icing detection methods are costly and bulky. Toward this end, a pitot-based icing detection method is proposed, and the effect of different types of icing blocking on pressure is firstly reported. An icing detection system based on the pitot tube is designed and fabricated. Icing wind tunnel results indicate that if the pitot tube is blocked by glaze ice, then the total pressure of the pitot tube decreases gradually and remains unchanged and less than static pressure. However, if the pitot tube is blocked by rime ice, then the total pressure drops to the same level as the static pressure. If the pitot tube is blocked by non-ice organic materials, then the total pressure suddenly drops to the same level as the static pressure and remains unchanged. Furthermore, if the pitot tube contacts the water droplets but does not freeze, the total pressure output value fluctuates slightly. The effect of icing on pressure is caused by differences in ice microstructure, temperature, and flow velocity. At the same time, the proposed method offers a facile and low-cost approach for UAV icing detection.

Continuous cooling transformation (CCT) diagrams of undeformed and 40% compressively deformed pearlite heat-resistant steels at 950°C were obtained by a combined method of dilatometry and metallogr...

Using lithium compounds as anode in ceramic fuel cells will form LiOH/Li2CO3 at the anode, which diffuse into the Gd-doped CeO2 (GDC) electrolyte significantly improving its ionic conductivity. Here the importance of the density and microstructure of the electrolyte on this conductivity improvement is analyzed. Test cells with Ni0.8Co0.15Al0.05LiO2 (NCAL) electrode and GDC electrolyte are prepared at four sintering temperatures of 900, 1100, 1300, and 1550 °C. The amount of LiOH/Li2CO3 that enters into the electrolyte from the NCAL anode decreases with increasing sintering temperature, which led to lower electrolyte ionic conductivity and fuel cell performance. The results of XPS and EPR show that the concentration of oxygen vacancy in GDC containing LiOH/Li2CO3 increased significantly. The effective interface of LiOH/Li2CO3-GDC composite electrolyte results in higher ionic conductivity as compared to the composite electrolytes with larger grains and a smaller amount of LiOH/Li2CO3 due to higher sintering temperatures.

Modern advanced photonic integrated circuits require dense integration of high-speed electro-optic functional elements on a compact chip that consumes only moderate power. Energy efficiency, operation speed, and device dimension are thus crucial metrics underlying almost all current developments of photonic signal processing units. Recently, thin-film lithium niobate (LN) emerges as a promising platform for photonic integrated circuits. Here, we make an important step towards miniaturizing functional components on this platform, reporting high-speed LN electro-optic modulators, based upon photonic crystal nanobeam resonators. The devices exhibit a significant tuning efficiency up to 1.98 GHz V−1, a broad modulation bandwidth of 17.5 GHz, while with a tiny electro-optic modal volume of only 0.58 μm3. The modulators enable efficient electro-optic driving of high-Q photonic cavity modes in both adiabatic and non-adiabatic regimes, and allow us to achieve electro-optic switching at 11 Gb s−1 with a bit-switching energy as low as 22 fJ. The demonstration of energy efficient and high-speed electro-optic modulation at the wavelength scale paves a crucial foundation for realizing large-scale LN photonic integrated circuits that are of immense importance for broad applications in data communication, microwave photonics, and quantum photonics., Lithium niobate (LN) devices are promising for future photonic integrated circuits. Here, the authors demonstrate an electro-optic LN modulator with a very small modal volume based on photonic crystal resonator architecture.

In this study, we present the use of compositionally and structurally well-defined, oxide-supported nanoparticle Ni + Ga intermetallic compound (IMC) catalysts in the wet reforming of propane. The ...

For the purpose of exploring a potential process to produce FeMn, the effects of microwave heating on the carbothermal reduction characteristics of oxidized Mn ore was investigated. The microwave heating curve of the mixture of oxidized Mn ore and coke was analyzed in association with the characterization of dielectric properties. The comparative experiments were conducted on the carbothermal reductions through conventional and microwave heatings at temperatures ranging from 973 to 1373 K. The thermogravimetric analysis showed that carbothermal reactions under microwave heating proceeded to a greater extent and at a faster pace compared with those under conventional heating. The metal phases were observed in the microstructures only under microwave heating. The carbothermal reduction process under microwave heating was discussed. The electric and magnetic susceptibility differences were introduced into the thermodynamics analysis for the formation of metal Mn. The developed thermodynamics considered that microwave heating could make the reduction of MnO to Mn more accessible and increase the reduction extent.

Effective disposal of radioactive iodine has been a persistent challenge in nuclear fuel recycling. Herein, we synthesized a series of micro-/mesoporous hierarchical adsorbents by the zeolitic imid...

Based on the density functional theory (DFT), the distribution of Al and Bronsted acid sites in zeolite ECR-1 were studied by utilization of SIESTA (Spanish Initiative for Electronic Simulations wi...

The disposal of powdery silica fume waste has become an urgent environmental problem, the synthesis of zeolitic materials using silica fume is a commendable remedy to this crisis. In this study, a cost-effective and facile one-step strategy was proposed for the first time for hydrothermal synthesis of ZSM-5 zeolite using silica fume waste with the aid of inexpensive metakaolin in the absence of organic templates. This method allowed the total transformation of silica fume into ZSM-5 which exhibited similar characteristics to those obtained from conventional chemical reagents. The as-synthesized ZSM-5 under the optimized condition was used to prepare Ni, Cu and Zn/ZSM-5 catalysts by means of ion exchange and calcination treatments for NOx removal by NH3-SCR, and they exhibited high NO conversion of 92, 100, and 95%, respectively. This study would be a promising candidate for cost-effective and environment friendly synthesis of zeolite using silica fume waste in large scale.

A series of compression tests were conducted at various temperatures and strain rates to experimentally investigate the hot-deformation characteristics and dynamic softening of an as-cast FeCrAl alloy. There is no evident decline in stress after the peak point of a flow curve despite the occurrence of dynamic recrystallization (DRX). This phenomenon pointed out that the occurrence of DRX in the alloy could not be identified depending only on flow curves. The constitutive equation for peak stress was constructed following the determination of hot-working parameters. The predicted results correlated well with the experimental data. The dynamic softening behavior was classified depending on the analysis of microstructure evolutions at different temperatures. The softening process was dominated by dynamic recovery (DRV) at 850 and 950 °C. The higher temperature could elevate the level of dynamic softening. The softening mechanisms at 1050 °C included DRV and continuous dynamic recrystallization (CDRX) characterized by the rotation of sub-grains from low-angle boundaries to high-angle boundaries. The rotation of sub-grains during the CDRX process was unlikely to affect the strong intensity of texture after the hot-deformation process.

Twinning is commonly activated in plastic deformation of low stacking-fault face-centered cubic (Fcc) metals but rarely found in body-centered cubic (Bcc) metals under room temperature and slow strain rates. Here, by conducting in situ transmission electron microscopy (TEM) at atomic scale, we discover that, in stark contrast to those in most Fcc metals, a majority of deformation twins in Bcc metals are unstable and undergo spontaneously detwinning upon unloading. Such unexpected instability of Bcc twins is found to be closely related to the prevalence of the inclined twin boundaries—a peculiar structure where twin boundaries are not parallel to the twinning plane, and the degree of instability is in direct proportion to the fraction of the inclined twin boundary. This work provides significant insights into the structure and stability of deformation twins in Bcc metals., Body-centred cubic metals rarely show twinning during deformation. Here, the authors use high resolution transmission electron microscopy to show tungsten, a body-centred cubic metal, spontaneously undergoes detwinning when unloaded.

Rare earths with unique electronic structure and properties have incomparable advantages for modifying the comprehensive performance of silicide materials. In this study, MoSi2-based composite coatings with different rare-earth Yb2O3 contents were prepared using supersonic atmospheric plasma spraying, and their microstructural features and oxidation behavior at 1700 °C were investigated systematically. Results showed that the sprayed MoSi2-Yb2O3 composite coating possessed the dense structure without visible defects and tightly adhered to the SiC transition layer. During oxidation at 1700 °C, all the samples exhibited an explicit linear oxidation mode, in which the MoSi2-10 wt%Yb2O3 coating qualified the optimal oxidation resistance with the lowest specific mass loss relative to other coatings. It was natural to consider that the Yb2O3 dopant changed the microstructural aspects of the formed oxide scale upon oxidation, and then affecting the oxidation behavior of the applied coating. Moderate doping of Yb2O3 stabilized the Si–O covalent bonds in SiO2 network, leading to the enhanced viscosity of oxide glass scale, thereby delaying the effective delivery of oxygen molecules as well as the oxidation degradation of the coating.

The phase transformation and microstructure evolution of pearlite heat-resistant steel during heating were observed with an ultra-high temperature confocal scanning laser microscope. The α-ferrite ...

Rare earth oxides usually play an active role in modifying the microstructure and oxidation resistance of silicide coatings, but its modification mechanism has not yet been clarified. In this work, molybdenum silicide (MoSi2) coating with different contents of ytterbium oxide (Yb2O3) was fabricated using supersonic atmospheric plasma spraying, and its microstructural evolution and oxidation behavior were investigated. Experimental results shown that the morphological characteristics of produced SiO2-rich glass scale varied with the doping of Yb2O3, which noticeably affected the oxidation resistance of sprayed MoSi2-Yb2O3 coatings. All coated specimens exhibited a parabolic oxidation behavior, wherein the MoSi2-10 wt%Yb2O3 coating possessed the smallest parabolic constant and the lowest specific mass loss with 100 h oxidation at 1500 °C due to the absence of SiC-depleted region and the formation of continuous multicomponent compound scale. Given this, Yb2O3 additive with proper concentration not only guaranteed the sufficient filling of open spaces in SiO2 network by Yb3+ cations, but also strengthened the Si–O bonds to increasing the viscosity of SiO2 glass, thereby delaying the effective delivery of reactive oxygen species inwardly.

Porous structured silicon has been regarded as a promising candidate to overcome pulverization of silicon-based anodes. However, poor mechanical strength of these porous particles has limited their volumetric energy density towards practical applications. Here we design and synthesize hierarchical carbon-nanotube@silicon@carbon microspheres with both high porosity and extraordinary mechanical strength (>200 MPa) and a low apparent particle expansion of ~40% upon full lithiation. The composite electrodes of carbon-nanotube@silicon@carbon-graphite with a practical loading (3 mAh cm−2) deliver ~750 mAh g−1 specific capacity, 92% capacity retention over 500 cycles. This work is a leap in silicon anode development and provides insights into the design of electrode materials for other batteries., The authors here construct hierarchical porous CNT@Si@C microspheres as anodes for Li-ion batteries, enabling both high electrochemical performance and excellent mechanical strength. The work highlights the importance of mechanical properties in developing battery materials for practical applications.

In this paper, a series of shape-memory poly(arylene ether ketone)s (PAKEs) with various flexible groups (i.e., carbolic bonds, ether, and ketone linkages) and entangled crystalline polymeric structures were synthesized by combining different bisphenol monomer (bisphenol A monomer and methyl hydroquinone monomer) proportions with a 4,4′-difluorobenzophenone monomer. The flexible parts and the entangled parts acted as a reversible phase and permanent phase, respectively. The prepared PAEK films exhibited excellent heat-triggered shape-memory behaviors with tunable glass transition temperatures (Tg) from 116 °C to 140.5 °C including an extremely high fixity ratio (over 98%), high recovery ratio (over 92%), and fast recovery rate (within 7.0 s). As increasing the content of the methyl hydroquinone monomer in the structural unit, the recovery ratio showed a downward trend, whereas the recovery time increased gradually. In addition, the electric-triggered shape-memory effect of the PAEK films was achieved via the introduction of carbon nanotubes (CNTs). Upon applying a voltage of 25 V, the recovery ratios of the composite films containing 10 wt% and 15 wt% CNTs were all over 80% (of 83.0% and 87.6%, respectively), indicating a great electric-triggered shape-memory behavior. The recovery ratio increased and the triggered voltage decreased as increasing the content of CNTs. The heat and electric dual-triggered shape-memory PAEK composites could be important smart materials possessing wide application prospects.

Lithium metal is a potential candidate for next-generation anode materials. However, the practical application of a lithium metal anode has been hindered by uncontrolled dendrite formation. Herein, a cost-effective single lithium ion conducting polymer electrolyte membrane based on a highly porous lithium sulfonated polyether ether ketone electrospun nanofiber membrane (es-LiSPCE) is designed to serve as both a separator and a lithium ion conductor. Impregnation of the ethylene carbonate (EC)/dimethyl carbonate (DMC) (v/v = 1 : 1) solvent mixture and 1 M LiFP6 in EC/PC (v/v = 1 : 1) yields gel pure es-LiSPCE and es-LiSPCE/1 M LiFP6 in an EC/PC (v/v = 1 : 1) membrane, respectively, which display high ionic conductivity, low interfacial compatibility and a high lithium ion transference number. Combined scanning electron microscopy (SEM) images and the long-term stripping/plating cycling test of lithium foil confirm that such a membrane is greatly favorable for inhibiting the formation of a concentration gradient and thus suppressing lithium dendrite growth. In addition, the fully aromatic polyether ether ketone backbone enables high thermal dimensional stability and high polarity and high polarity enables fast electrolyte wetting of the es-LiSPCE membrane. Notably, Li/LiFePO4 cells fabricated using es-LiSPCE membranes demonstrate promising rate capacity at 6C, and excellent electrochemical stability for 1500 cycles even at 6C. Therefore, it is believed that such an electrolyte can serve as an alternative to conventional polyolefin-based separators for high energy density lithium metal batteries.

By utilizing a flexible fluorinated bis(triazole) ligand 1,4-bis(1,2,4-triazole-1-ylmethyl)-2,3,5,6-tetrafluorobenzene (Fbtx), a thermally and chemically stable cobalt(II)-containing tungstovanadate-based metal–organic framework (MOF) {[Co3(Fbtx)5(V2W18O62)(H2O)2]·26H2O}n (denoted as CZU-5) was synthesized and structurally characterized. The X-ray structural analysis revealed that CZU-5 features a three-dimensional (3-D) self-penetrated α-polonium cubic structure, which results from a 3-D 4-fold interpenetrated diamondoid [Co(Fbtx)]n network connected by the Wells–Dawson-type tungstovanadate clusters. Unexpectedly, the introduction of vanadium atoms as heteroatoms into the Dawson-type anion in polyoxometalate (POM)-based coordination polymers has not been reported to date. For the first time, the POM-based material was demonstrated to be an effective catalyst for the solvent-free ring-opening polymerization of e-caprolactone. Moreover, the CZU-5 catalyst could be recycled up to five times with the retention of both catalytic activity and crystal structure.

In recent years, graphene oxide quantum dots (GOQDs) have emerged as novel nanomaterials for optical sensing, bioimaging, clinical testing, and environmental testing. However, GOQDs demonstrate unique photoluminescence properties, with GOQDs having quantum limitations and edge effects that often affect the accuracy of the test results in the sensory field. Herein, GOQDs with a large content of hydroxyl groups and low fluorescence intensity were first prepared via an improved Fenton reaction in this study, which introduces a large amount of epoxy groups to break the C–C bonds. The synthesized GOQDs show no significant variation in the fluorescence intensity upon ultraviolet and visible light excitations. We further utilized the GOQDs as fluorescence quenchers for different fluorescent dyes in real-time fluorescence quantitative polymerase chain reaction (qRT-PCR), and verified that the addition of GOQDs (5.3 μg ml−1) into a qRT-PCR system could reduce the background fluorescence intensity of the reaction by fluorescence resonance energy transfer (FRET) during its initial stage and its non-specific amplification, and improve its specificity. In addition, the qRT-PCR method could detect two different lengths of DNA sequences with a high specificity in the 104 to 1010 copies per μl range. It is of paramount importance to carry out further investigations to establish an efficient, sensitive, and specific RT-PCR method based on the use of GOQD nanomaterials as fluorescence quenchers.

By using La(NO3)3•6H2O, Ca(NO3)2•4H2O, and Mn(CH3COO)2•4H2O as starting raw materials together with methanol, three kinds of La0.67Ca0.33MnO3 (LCMO) solutions, denoted as LCMO–BzAc, LCMO–AcAc, and LCMO–BPY, respectively, were obtained. The samples were fabricated via the photosensitive solution method with benzoylacetone (BzAc), acetylacetone (AcAc), and 2, 2′-bipyridine (BPY) as chelating reagents. The chelation mechanism of the metal ions was investigated via ultraviolet spectroscopy. The photosensitive compounds were decomposed after UV exposure and their products reduced the solubility of the LCMO gel films in organic solvents. The patterned LCMO thin films were then fabricated by using the self-photosensitive properties of their gel films. Through the mask micromachining process, the LCMO micropatterns prepared by using the LCMO–BzAc solution exhibited the highest quality. Moreover, they also presented good performance when the mask-free method was employed. The magnetic properties of the micropatterned LCMO films were investigated in detail and the results revealed that the micropatterning did not influence their saturation magnetization.