SiCp/ Al composites containing high volume fraction of SiC particles were fabricated by spark plasma sintering （SPS）. and their thermophysical properties, such as thermal conductivity （TC） and *** of thermal expan...
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SiCp/ Al composites containing high volume fraction of SiC particles were fabricated by spark plasma sintering （SPS）. and their thermophysical properties, such as thermal conductivity （TC） and *** of thermal expansion （CTE）, were characterized. The electric field in the vacuum column was calculated and the generation condition of the spark was analyzed. Spark can be generated by a low current if the cavity in the green body is large enough. A high relative density of the composites was successfully achieved through the optimization of sintering parameters. The measured TCs of the SiCp/ Al composites fabricated by SPS are higher than 195 W/m ·K.
Both silica and boron-silica glass materials doped with terbium organic complex were prepared by in situ sol-gel method respectively. XRD and SEM measurements were performed to verify the non-crystalline structure of ...
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Both silica and boron-silica glass materials doped with terbium organic complex were prepared by in situ sol-gel method respectively. XRD and SEM measurements were performed to verify the non-crystalline structure of the glass. The influence of the glass contents on the structure of the glass and the erwrgy level of the doped Tb （Ⅲ） ions was analyzed by the emission spectra and IR spectra. The effect of B2O3 on the photolumirwscence properties of rare earth organic complex in silica- based glass was investigated. The IR spectra indicate that the in situ sylthesized rare earth complex molecule was confined to the micropores of the bost and the vibration of the ligands was frozen. When B2O3 was added into the silica host gel, B2O3 had little influence on the noncrystallirw structure of the glass, and BO3 triangle, which had a layer structure different from the silica framework, could form. So the silica network became more inhomogenous, and the luminescence of terbium complexes was quenched with the increase of the B2O23 amount.
ZrB2 ceramics were prepared by self-propagating high-temperature synthesis（SHS） and were sintered by hot pressing（HP）.The effects of the granularities and doses of raw materials in Zr-B2O3-Mgon SHS process and pro...
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ZrB2 ceramics were prepared by self-propagating high-temperature synthesis（SHS） and were sintered by hot pressing（HP）.The effects of the granularities and doses of raw materials in Zr-B2O3-Mgon SHS process and product were *** and combustion temperature curves prove that the ideal SHS reactants of Zr-B2O3-Mg are 50μm Zr powder,75μm B2O3 powder and 400μm Mg powder with 45% *** particle sizes of SHS product,acid-leached product,sintered product are 2-5μm,0.5-2μm,2-10μm *** analysis indicates that the acid-leached product consists of ZrB2（94.59%）,ZrO2（3.87%）,and H3BO3（1.54%）,The sintered product has a relative density of 95.4%.
Both titanium and germanium were introduced into silicon dioxide system by sol-gel method to move its region of anomalous dispersion caused by IR resonance absorption towards the wavelength of CO 2 *** is indicated b...
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Both titanium and germanium were introduced into silicon dioxide system by sol-gel method to move its region of anomalous dispersion caused by IR resonance absorption towards the wavelength of CO 2 *** is indicated by IR absorption spectra that as the content of SiO 2 decreases in this glass system TiO 2 and GeO 2 tends to exist in their own *** for the gel glass with a composition of 40SiO 2·30TiO 2·30GeO 2,when the temperature is below 600℃,germanium atoms exist mainly in Ge-O-Ge *** the temperature increasing from 800℃ to 1000℃, titanium atoms in Si-O-Ti bonds almost transform into Ti-O-Ti ***,a large number of Si-O-Ti and Si-O-Ge bonds formed when the temperature approaches 800℃,which makes a notable IR absorption band round the wavelength of CO 2 ***, sol-gel based SiO 2-TiO 2-GeO 2 gel glass is a candidate material for CO 2 laser hollow waveguide.
Highly oriented calcium carbonate lamellas are exquisite structure produced by biomineralization. Strategies mimicking nature have been developed to synthesize inorganic materials with excellent structures and optimal...
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Highly oriented calcium carbonate lamellas are exquisite structure produced by biomineralization. Strategies mimicking nature have been developed to synthesize inorganic materials with excellent structures and optimal properties. In our strategy, egg white protein and zinc ion were employed in the solution to induce the crystallization of calcium carbonate, resulting in the macroscopic aragonite laminate with an average length of 1.5 mm, which was comprised of single-crystalline tablets. During the crystallization at initial stage, it was found that the particles displayed the characteristics of amorphous calcium carbonate, which was then transformed into the sophisticated structured aragonite through a multistage assembly process. The rebuilt nacre structure in vitro was achieved owing to the synergistic effects of egg white protein and zinc ion.
Doped SrTiO3 capacitor-varistor multifunctional ceramics were fabricated by a single sintering process. AC complex impedance analysis was performed to investigate electrical features of grains and grain boundaries for...
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Doped SrTiO3 capacitor-varistor multifunctional ceramics were fabricated by a single sintering process. AC complex impedance analysis was performed to investigate electrical features of grains and grain boundaries for both as-reduced ceramic and reoxidized ceramics. The results showed that the as-reduced ceramic exhibited inductive response at high frequencies above 2 MHz, which is attributed to the contribution of electron behavior in semiconducting grains. The high frequency inductive response disappeared in impedance plots of reoxidized ceramics.
In this paper, a novel accelerated test method was proposed to analyze the durability of MEA, considering the actual operation of the fuel cell vehicle. The proposed method includes 7 working conditions： open circuit...
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In this paper, a novel accelerated test method was proposed to analyze the durability of MEA, considering the actual operation of the fuel cell vehicle. The proposed method includes 7 working conditions： open circuit voltage （OCV）, idling, rated output, overload, idling-rated cycle, idling-overload cycle, and OCV-idling cycle. The experimental results indicate that the proposed method can effectively destroy the MEA in a short time （165 h）. Moreover, the degradation mechanism of MEA was analyzed by measuring the polarization curve, CV, SEM and TEM. This paper may provide a new research direction for improving the durability of fuel cell.
All-solid-state lithium batteries(ASSLBs),which use solid electrolytes instead of liquid ones,have become a hot research topic due to their high energy and power density,ability to solve battery safety issues,and capa...
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All-solid-state lithium batteries(ASSLBs),which use solid electrolytes instead of liquid ones,have become a hot research topic due to their high energy and power density,ability to solve battery safety issues,and capabilities to fulfill the increasing demand for energy storage in electric vehicles and smart grid ***-type solid electrolytes have attracted considerable interest as they meet all the properties of an ideal solid electrolyte for *** garnet-type Li_(7)La_(3)Zr_(2)O_(12)(LLZO)has excellent environmental stability;experiments and computational analyses showed that this solid electrolyte has a high lithium(Li)ionic conductivity(10^(-4)-10^(-3) S·cm^(-1)),an electrochemical window as wide as 6 V,stability against Li metal anode,and compatibility with most of the cathode *** this review,we present the fundamentals of garnet-type solid electrolytes,preparation methods,air stability,some strategies for improving the conductivity based on experimental and computational results,interfacial issues,and finally applications and challenges for future developments of LLZO solid electrolytes for ASSLBs.
Polycrystalline samples of Sr5PrTi3Ta7O30 （SPTT） and Sr5EuTi3Ta7O30 （SETT） compounds were prepared by high-temperature solid-state reaction method and their formation, structure and dielectric properties were stud...
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Polycrystalline samples of Sr5PrTi3Ta7O30 （SPTT） and Sr5EuTi3Ta7O30 （SETT） compounds were prepared by high-temperature solid-state reaction method and their formation, structure and dielectric properties were studied. They are found to be ferroelectric phase of filled tetragonal tungsten bronze （TB） structure at room temperature and undergoes diffuse type of ferroelectric-paraelectric phase transition around 34 ℃ and 31 ℃, respectively. At 1 MHz SPTT exhibits high dielectric constants of 177 and low dielectric losses of 3.5×10^-4 and SETT has high dielectric constants of 125 and low dielectric losses of 2.4×10^-3.
Antimony doped tin oxide（ATO） thin films have been prepared by pulsed laser deposition（PLD） *** intrinsic effect of Sb dopant,including the Sb content,transition degree between Sb（3＋） and Sb（5＋） and crystall...
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Antimony doped tin oxide（ATO） thin films have been prepared by pulsed laser deposition（PLD） *** intrinsic effect of Sb dopant,including the Sb content,transition degree between Sb（3＋） and Sb（5＋） and crystallinity on the electrical and optical properties of the ATO thin films is mainly *** is suggested that the transition degree of Sb（3＋） towards Sb（5＋）（Sb（5＋）/Sb（3＋） ratio） is determined by Sb *** the Sb content is increased to 12 at%,the Sb（5＋）/Sb（3＋） ratio reaches the highest value of 2.05,corresponding to the resistivity of 2.70×10（-3） Ω·***,the Burstein-Moss effect caused by the increase of carrier concentration is observed and the band gap of the ATO thin films is broadened to 4.0 eV when the Sb content is increased to 12 at%,corresponding to the highest average optical transmittance of 92%.Comprehensively considering the combination of electrical and optical properties,the ATO thin films deposited with Sb content of 12 at%exhibit the best properties with the highest ＂figure of merit＂ of 3.85×10（-3） Ω（-1）.Finally,an antimony selenide（Sb_2Se_3） heterojunction solar cell prototype with the ATO thin film as the anode has been prepared,and a power conversion efficiency of 0.83%has been achieved.
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