A bio-inspired layered material of reduced graphene oxide（RGOs） and calcium carbonate was synthesized via a one-pot strategy in DMF/H2O mixed solvent. The experimental results show that the product is a layered mate...
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A bio-inspired layered material of reduced graphene oxide（RGOs） and calcium carbonate was synthesized via a one-pot strategy in DMF/H2O mixed solvent. The experimental results show that the product is a layered material of wrinkled RGOs networks and micron-sized calcium carbonate particles with uniform granular diameter and homogeneous morphology, which are distributed between the layered gallery of the graphene scaffold. The polymorph and the morphology of the in-situ produced calcium carbonate particles can be manipulated by simply changing the temperature scheme. Besides, the graphene oxide was reduced to a certain extent, and the hierarchical wrinkles were generated in the RGOs layer by the in-situ formation of the calcium carbonate particles. This work provides a facile and controllable strategy for synthesizing layered material of RGOs and carbonates, and also presents a platform for making three-dimensional porous wrinkled RGOs networks.
Naturally abundant transition metal oxides with high theoretical capacity have attracted more attention than commercial graphite for use as anodes in lithium-ion batteries. Lithium-ion battery electrodes that exhibit ...
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Naturally abundant transition metal oxides with high theoretical capacity have attracted more attention than commercial graphite for use as anodes in lithium-ion batteries. Lithium-ion battery electrodes that exhibit excellent electrochemical performance can be efficiently achieved via three-dimensional （3D） architectures decorated with conductive polymers and carbon. As such, we developed 3D carbon-supported amorphous vanadium oxide microspheres and crystalline V203 microspheres via a facile solvothermal method. Both samples were assembled with ultrathin nanosheets, which consisted of uniformly distributed vanadium oxides and carbon. The formation processes were clearly revealed through a series of time-dependent experiments. These microspheres have numerous active reaction sites, high electronic conductivity, and excellent structural stability, which are all far superior to those of other lithium-ion battery anodes. More importantly, 95% of the second-cycle discharge capacity was retained after the amorphous microspheres were subjected to 7,000 cycles at a high rate of 2,000 mA/g. The crystalline microspheres also exhibited a high-rate and long-life performance, as evidenced by a 98% retention of the second-cycle discharge capacity after 9,000 cycles at a rate of 2,000 mA/g. Therefore, this facile solvothermal method as well as unique carbon-supported and nanosheet-assembled microspheres have significant potential for the synthesis of and use in, respectively, lithium-ion batteries.
High resolution and full-color light-emitting diodes require precise and efficient patterning of light-emitting structures containing quantum dots or *** report light-induced inverted patterning of nanocrystals in gla...
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High resolution and full-color light-emitting diodes require precise and efficient patterning of light-emitting structures containing quantum dots or *** report light-induced inverted patterning of nanocrystals in glasses for micro-light-emitting *** laser pulse induces structural destruction and amorphization of nanocrystals in glasses,forming inverted luminescent ***-throughput patterning of micrometer-scale,thermally stable,and highly photoluminescent structures in nanocrystals embedded glass is *** patterning method provides a novel way to fabricate high-performance and ultrahigh-resolution color conversion layers for micrometer-scale light-emitting diodes.
Inspired by structures of natural shells,zirconia-carbon nanocomposites were obtained by using natural chitin from shrimp shells as templates via the sol-gel route in this *** was dispersed in the water and chelated w...
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Inspired by structures of natural shells,zirconia-carbon nanocomposites were obtained by using natural chitin from shrimp shells as templates via the sol-gel route in this *** was dispersed in the water and chelated with the zirconia precursors by *** a heat treatment for carbonization,nacre-like structures of carbon-zirconia nanocomposites were successfully *** to the toughening mechanism of tetragonal zirconia,the mechanical properties of carbon-zirconia composites are further *** as-received zirconia/carbon nanocomposite with best mechanical property has a hardness of 5.88GPa and an elastic modulus of 80.6 GPa,which is even stronger than natural *** work might facilitate a versatile platform for developing green nanocomposites with reasonably good mechanical properties.
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.
Silicide-based thermoelectrics are examples of cost-efficient and environmentally friendly new energy materials, which can be used for power-generation applications in the range of 500–800 K. We review the research f...
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Silicide-based thermoelectrics are examples of cost-efficient and environmentally friendly new energy materials, which can be used for power-generation applications in the range of 500–800 K. We review the research focusing on the exploration of n-type Mg2IV-based solid solutions(IV = Si, Ge and Sn) and summarize the most prominent discoveries achieved so far in their studies. Owing to their superior performance compared to other silicides, including p-type Mg2IV, higher manganese silicides(HMS) are commonly considered as a suitable p-type material to be used in thermoelectric modules in conjunction with n-type Mg2IV-based solid solutions for mid-temperature power-generation applications. We describe the strategies used to improve the thermal and electronic transport properties of n-type Mg2IV-based solid solutions and mention some key features of HMS. We also point out the importance of mechanical properties and thermal stability of this family of materials and offer perspectives on the future research work to further improve their performance.
Sb is a very effective dopant for ZrNiSn based half-Heusler *** effect of Ti substitution on Zr0.75Hf0.25NiSn0.985Sb0.015half-Heusler（HH） semiconductor alloys has been investigated to explore the structural modifica...
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Sb is a very effective dopant for ZrNiSn based half-Heusler *** effect of Ti substitution on Zr0.75Hf0.25NiSn0.985Sb0.015half-Heusler（HH） semiconductor alloys has been investigated to explore the structural modifications and composition ***0.25Zr0.75-xNiSn0.985Sb0.015（x=0,0.15,0.30,0.45） alloys were synthesized by induction melting.A set of samples was also annealed for comparative *** samples were then sintered using plasma activated sintering（PAS） *** results confirmed the existence of ZrNiSn type HH *** electron（BSE） images showed phase separations in the *** substitution improved the carrier concentration and electrical conductivity of the ***,thermal conductivity was also significantly reduced due to the enhanced phonon ***,a ZT value of 1.11 at 873 K was obtained for 30% Ti substituted（annealed） sample.
WC- 10Co nanocomposite powder produced by spray pyrolysis-continuoas reduction and carbonization technology was used, and the vacuum sinteriag plus sinterhip process was cdopted to prepare ultrafine WCCo cemented carb...
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WC- 10Co nanocomposite powder produced by spray pyrolysis-continuoas reduction and carbonization technology was used, and the vacuum sinteriag plus sinterhip process was cdopted to prepare ultrafine WCCo cemented carbide. The microstructure, grain size, porosity, density, Rockwell A hardness （ HRA ）, transverse rupture strength （ TRS ） , saturated magnetization and coercivity force were studied. The experimental results show that average grain size of the sample prepared by vacuum sintering plas sinterhip technology was about 420 nm, transverse rupture strength was more than 3460 MPa, and Rockwell A hardness of sintered specimen was more than 92.5. Ultrafine WC- 10Co cemented carbide with high strength and high hardness is obtained.
The grain-boundary resistance of ZrO2 mainly consists of the contribution from the space-charge layers Rsc and that from the grain-boundary phase Rgbp The reduction of Rsc can be realized by the segregations of solute...
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The grain-boundary resistance of ZrO2 mainly consists of the contribution from the space-charge layers Rsc and that from the grain-boundary phase Rgbp The reduction of Rsc can be realized by the segregations of solutes with positive effective charge in the space-charge layers,while the reduction of Rgbp can be achieved by decreasing the amount of the grain-boundary phase,changing the morphology of the phase and forming grain-boundary phase with high *** best grain-boundary design effect can only be achieved by the joint design of the space-charge layers and the grain-boundary phase.
In this study, cryogenic cycling treatment was used to process the hot-rolled Mg-4.5Al-2.5Zn alloy sheets to research the influence on mechanical properties and microstructure. Optical microscopy, electron back-scatte...
In this study, cryogenic cycling treatment was used to process the hot-rolled Mg-4.5Al-2.5Zn alloy sheets to research the influence on mechanical properties and microstructure. Optical microscopy, electron back-scatter diffraction and transmission electron microscopy were applied to characterize the microstructures and analyze the mechanisms. The consequences indicate that the cryogenic cycling treatment has significantly influence on improving the mechanical properties. With the cycle of cryogenic cycling treatment increasing to 5 cycles, the sample processed by 3 cycles presents the highest ductility (~ 18.6%), while the 4-cycle one shows the highest strength (~ 311.8 MPa). The improvement can be attributed to fine grains, introduced high-density dislocation, 9.8%-fraction low-angle grain boundaries (LAGBs), the precipitation of Mg17Al12 phase and the texture with the intensity of 17.5. Although the average grain sizes of the samples processed by cryogenic cycling treatment have no obvious difference, internal stress variations induced by cryogenic cycling treatment significantly influence LAGBs, the basal texture evolution, and the prismatic < a > slip, pyramidal < c > slip and pyramidal < c + a > slip activation.
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