Highly oriented plate-like rod/tube arrays of ZnO are synthesized by a solution-based approach at low temperature. The ZnO rod/tube arrays grow oriented vertically on silicon substrate and the intersectant ZnO nanoshe...
Highly oriented plate-like rod/tube arrays of ZnO are synthesized by a solution-based approach at low temperature. The ZnO rod/tube arrays grow oriented vertically on silicon substrate and the intersectant ZnO nanosheets stand on the backbones of ZnO rods/tubes. The constructions of plate-like rod or tube arrays depend on the processing conditions. The growth mechanisms are investigated based on the nucleation and growth process. The initial ZnO film formed on substrate is crucial for the growth of ZnO rods/tubes perpendicular to the substrate. The nanosheets grow around the ZnO rods/tubes by the secondary nucleation and growth process. The ZnO tubes are formed by the etching of the ZnO polar faces. The novel ZnO structures are expected to have great potential for electronics, photoelectronics, sensors, and catalysis etc.
Samples of LiNi0.95-xCoxAl0.05O2（x=0.10 and 0.15） and LiNiO2,synthesized by the solid-state reaction at 725?℃ for 24?h from LiOH·H2O,Ni2O3,Co2O3,and Al（OH）3 under an oxygen stream,were characterized by TG-DT...
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Samples of LiNi0.95-xCoxAl0.05O2（x=0.10 and 0.15） and LiNiO2,synthesized by the solid-state reaction at 725?℃ for 24?h from LiOH·H2O,Ni2O3,Co2O3,and Al（OH）3 under an oxygen stream,were characterized by TG-DTA,XRD,SEM,and electrochemical tests. Simultaneous doping of cobalt and aluminum at the Ni-site in LiNiO2 was tried to improve the cathode performance for lithium-ion batteries. The results showed that co-doping （especially,5% Al and 10% Co in atomic fraction） definitely had a large beneficial effect in increasing the capacity （186.2?mA·h/g of the first discharge capacity for LiNi 0.85 Co 0.1 0Al 0.05 O2） and cycling behavior (180.1?mA·h/g after 10 cycles for LiNi0.95-xCoxAl0.05O2) compared with 180.7?mA·h/g of the first discharge capacity and 157.7?mA·h/g of the tenth discharge capacity for LiNiO2,respectively. Differential capacity versus voltage curves showed that the co-doped LiNi0.95-xCoxAl0.05O2 had less intensity of the phase transitions than the pristine LiNiO2.
In situ reaction method was undertaken to fabricate A1N-BN composites in this paper. Factors including temperature, heat preservation time, and the ratio of Al to BN were investigated in this system. DTA and XRD were ...
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In situ reaction method was undertaken to fabricate A1N-BN composites in this paper. Factors including temperature, heat preservation time, and the ratio of Al to BN were investigated in this system. DTA and XRD were employed to character the phases of production. SEM was conducted to observe the microstructure of the samples. The results showed that the grains tended to perfect with the increasing of the sintering temperature and soaking time. Optimum parameters were temperature of 1000°C and 1.5 h for soaking time.
AlN was synthesized by in situ reaction with Al and BN in this paper. AlN-BN composites were fabricated by hot-pressed sintering without additives. The relationship between the ratio of Al to BN and microstructure and...
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AlN was synthesized by in situ reaction with Al and BN in this paper. AlN-BN composites were fabricated by hot-pressed sintering without additives. The relationship between the ratio of Al to BN and microstructure and properties were studied. The results show that the content of AlN increases with the ratio of Al to BN increasing, and the density, hardness, bending strength, thermal conductivity and dielectric constant also increase with the ratio of Al to BN increasing. The results show that the samples with thermal conductivity 63.5 W/m·K and dielectric constant 8.76 are acquired by hot-pressed sintering under nitrogen atmosphere and two hours soaking time.
The hydrophilic-hydrophobic adjustable catalyst layers, with contact angle of 78°-130°, were prepared successfully by using of microemulsion method. The as-result samples were characterized by the I-V curve ...
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The hydrophilic-hydrophobic adjustable catalyst layers, with contact angle of 78°-130°, were prepared successfully by using of microemulsion method. The as-result samples were characterized by the I-V curve of its single cell, EIS, CV, SEM, TEM. It is found that an appropriate dosage of PTFE in the catalyst layers can optimize the micro-structure of the catalyst layer, and improve the stability of the cell. the best composition of the catalyst layer was Pt/C : Nafion : PTFE = 9 : 3 : 1.
Al2O3/WC-10Co/ZrO2 cermets were prepared by a hot-pressing process by using WC-10Co nanocomposite powder, Y2O3 stabilized nanocrystalline ZrO2 powder and submicron Al2O3 powder. The influences of sintering temperature...
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Al2O3/WC-10Co/ZrO2 cermets were prepared by a hot-pressing process by using WC-10Co nanocomposite powder, Y2O3 stabilized nanocrystalline ZrO2 powder and submicron Al2O3 powder. The influences of sintering temperature on the microstructure, grain size and properties were investigated according to the density, fracture toughness, Rockwell A hardness (HRA), hysteresis loops and scanning electron microscopy (SEM) micrographs of fractured surfaces of the specimens. The results show that the composite powders (WC-10Co(50%)/Al2O3(40%)/ZrO2(10%)) after being high-energy ball-milled for 48 h was hot-pressing sintered at 1450°C, then submicron Al2O3/WC-10Co/ZrO2 cermets with an average grain size of less than 1 μm and better properties of 97.5% in relative density, 7.4468 MPa·m1/2 in fracture toughness, HRA 94.0 is achieved.
The physical performances of alumina cement-based composite fabricated by vibratory compaction by using alumina cement as gelling agent and graphite as conductive filler were studied in this paper. The change trends o...
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The physical performances of alumina cement-based composite fabricated by vibratory compaction by using alumina cement as gelling agent and graphite as conductive filler were studied in this paper. The change trends of volume resistivity, compressive strength and apparent density of these composite with graphite content were obtained. And the percolation theory was applied to explain the electrical mechanism of these composites. The experimental results showed that the volume resistivity of these composites varied in 106-102Ω·cm, which can be used as antistatic, electric engineering and electro thermal materials.
The performance of proton exchange membrane is mainly influenced by water content and distribution in proton exchange membrane for PEM fuel cell, and influence factors of the water content and the distribution in memb...
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The performance of proton exchange membrane is mainly influenced by water content and distribution in proton exchange membrane for PEM fuel cell, and influence factors of the water content and the distribution in membrane mainly include the pressure, the temperature, the electric current and so on. This text has discussed the influence of pressure to water content and distribution in proton exchange membrane, and we made the ingenious experimental design to measure directly the distribution of water content in membrane. We have got the disciplines of water content and distribution in membrane under pressure. Experiment reveals that the influence of pressure to water content in membrane is small and water distribution among membrane is average, these conclusions do not accord with model completely.
Nafion/PTFE composite membranes based on different ePTFE were prepared in this work. Porous PTFE was perfectly impregnated by Nafion resin. The differences of mechanical properties such as tensile strengths and dimens...
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Nafion/PTFE composite membranes based on different ePTFE were prepared in this work. Porous PTFE was perfectly impregnated by Nafion resin. The differences of mechanical properties such as tensile strengths and dimensional changes were analyzed in this paper. From electrochemical and single cell tests, the optimum thickness of porous PTFE for the composite membrane is 15 μm. The performance of the composite membrane based on the 15 μm-thick porous PTFE was 0.664 V at 600 mA/cm2, which was higher than Nafion111 membrane at the same conditions.
The paper make a brief introduction to PEMFC dynamic model, which shows the development of PEMFC from simple cell to cell system in recent decade. Put forward some problem existing in current dynamic modeling, point o...
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The paper make a brief introduction to PEMFC dynamic model, which shows the development of PEMFC from simple cell to cell system in recent decade. Put forward some problem existing in current dynamic modeling, point out some potential developing direction of modeling: 1) describing cell's inner process from microcosmic side more really, establishing a mechanism model including electrode process dynamic and electrochemistry thermodynamics (energetics);2) from macroscopical side , developing a united mathematic model which can be used to describe PEMFC system roundly from macroscopical side.
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