Microstructures of highly compact IrO2 films, deposited on Si (100) substrates by pulsed laser deposition of Ir target at different oxygen partial pressures, were characterized with X-ray diffraction (XRD), Raman spec...
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Microstructures of highly compact IrO2 films, deposited on Si (100) substrates by pulsed laser deposition of Ir target at different oxygen partial pressures, were characterized with X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM).The results show that the films, grown at an oxygen partial pressure of 20 Pa and at a substrate temperature in the range of 250°-500°C, are polycrystalline and that as the substrate temperature rises, IrO2 surface becomes rougher with bigger grains.
The relations between composition, structure, chemical bond and property of TiC, FeAl, Fe3Al and composites of TiC/Fe-Al series were studied by using density function theory and discrete variation method (DFT-DVM). Th...
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The relations between composition, structure, chemical bond and property of TiC, FeAl, Fe3Al and composites of TiC/Fe-Al series were studied by using density function theory and discrete variation method (DFT-DVM). There were strong ionic and covalent interacts among the interfaces of TiC/FeAl and TiC/Fe3Al composites. The ionic bonds became weak, and the covalent was strong gradually from the single phase of TIC, FeAl or Fe3Al, to composite TiC/FeAl or TiC/Fe3Al. The interaction of the orbitals and the covalent bond of TiC/Fe3Al were stronger than those of TiC/FeAl. The results were consistent with the experiment of bending strength when the content of Al increases in the TiC/Fe-Al system.
Sodium niobate (NaNbO3) nanometer-size particles having antiferroelectric property were successfully prepared via a hydrothermal process. When NaOH, about 8~10 times as much as Nb2O5(3~4 mol/L NaOH), reacted with Nb2O...
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Sodium niobate (NaNbO3) nanometer-size particles having antiferroelectric property were successfully prepared via a hydrothermal process. When NaOH, about 8~10 times as much as Nb2O5(3~4 mol/L NaOH), reacted with Nb2O5 particles at 160~180°C under hydrothermal conditions, pure orthorhombic phase NaNbO3 characterized by using X-ray powder diffraction was obtained. The unit cell parameters were a = 9.5597, α = β = γ = 90°, c = 5.7873. The hydrothermal reaction significantly lowered the temperature required for synthesizing NaNbO3 and the size of NaNbO3 particles. And TEM analysis showed the size of NaNbO3 particles was about 0.02~0.05 μm.
The effects of fuel cell structures and operating condition on the performance of proton exchange membrane fuel cells are discussed. The results show: there are optimal ranges about the contents of PTFE and Nafion in ...
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The effects of fuel cell structures and operating condition on the performance of proton exchange membrane fuel cells are discussed. The results show: there are optimal ranges about the contents of PTFE and Nafion in catalyst layers. Fine fuel cell structures and scales are benefit to the uniform distribution of reaction gas, the discharging of production, the reduction of fuel cell internal resistances. Increasing the porosity and aperture of diffusion layers can increase the limiting current density of fuel cells. Decreasing the thickness of the membrane will decrease the internal resistances of fuel cell. Raising temperature and pressure will improve electrochemical reaction and reduce transport resistances. The humidification temperature and velocity of the reaction gas should vary with the current density.
The relations among composition, structure, chemical bond and property of composites of TiC/Al2O3 ceramic and doped series are studied by using density function and discrete variation method (DFT-DVM). There are stron...
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The relations among composition, structure, chemical bond and property of composites of TiC/Al2O3 ceramic and doped series are studied by using density function and discrete variation method (DFT-DVM). There are strong ionic and covalent interactions between two phases of TiC/Al2O3, the interaction becomes stronger when doping Ni into TiC/Al2O3, and the interaction of doping Mo into TiC/Al2O3 is stronger than that of doping Ni. The results are consistent with the experiment that doping can improve the combination of the phases in TiC/Al2O3, enhance hardness and et al, and the improvement of doping Mo is more obvious than that of doping Ni.
TiB2 powders coated with BN were prepared by Hybridization System making use of dry impact blending method to achieve powder surface modification. Parameters of coating were analyzed and the most appropriate condition...
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TiB2 powders coated with BN were prepared by Hybridization System making use of dry impact blending method to achieve powder surface modification. Parameters of coating were analyzed and the most appropriate condition was summarized. Scan electron microscope of JSM-5610LV and transmission electron microscope of H-600STEM/EDS were used to observe the microstructure of coated powders. Results show that treatment time, rotation speed, granularity ratio of TiB2 to BN, pretreatment of materials etc influence the coating results evidently. Mixing raw materials and coating with BN under the appropriate condition can get round TiB2/BN composite powder with smooth surface and compact coating layer.
The transport dynamics of proton exchange membrane fuel cell( PEMFC) is very important to understand its working mechanism and to realize optimization control. A single-channel, three-dimensional model has been develo...
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The transport dynamics of proton exchange membrane fuel cell( PEMFC) is very important to understand its working mechanism and to realize optimization control. A single-channel, three-dimensional model has been developed to study the change of relative humidity of reactant and current density;Dynamic simulation includes average number of H2O/SO42- of membrane surface at cathode, diffusion of oxygen, pressure of channel inlet/outlet, gas flow rate and so on. The conclusion has reference significance regarding the correlated research.
Ca3Cc2O6 is one kind of potential oxide thermoelectric materials. Sol-gel method was applied to synthesize Ca3Co2O6 powder, dried gel and powders are studied systemically with testing measures of the TG/DSC, XRD and S...
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Ca3Cc2O6 is one kind of potential oxide thermoelectric materials. Sol-gel method was applied to synthesize Ca3Co2O6 powder, dried gel and powders are studied systemically with testing measures of the TG/DSC, XRD and SEM. The pH, glycol and calcined temperature were taken into account as main influence factors. It was found during the research that the use of glycol can lighten agglomerates, benefit to auto-combustion, and had no effect on the phases finally. At the same time, Ca3Co2O6 was the offspring of decomposed Ca3Co4O9 at certain calcined condition.
The article reported a method of boronize medium absorbing microwave to fabricate boronization layer in the steel surface, and compares it with traditional boronization. The results indicated that the boron atoms for ...
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The article reported a method of boronize medium absorbing microwave to fabricate boronization layer in the steel surface, and compares it with traditional boronization. The results indicated that the boron atoms for the development of boronization layer were rooted in those produced by medium decomposition and gaseous boride, just like the traditional boronization. The growth of boronization layer in microwave was characterized with less than or equal 002> crystal orientation. Its growth rate of boronization layer was faster than that in traditional treatment. Besides temperature effect, growth rate was also influenced by activity boron atom in microwave diffusion in boronization layer.
In this research, we developed a three-dimensional finite-difference-time-domain algorithm that incorporated the Lorentz-Drude model through the use of Z-transform technique. This algorithm was used to compute the spe...
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In this research, we developed a three-dimensional finite-difference-time-domain algorithm that incorporated the Lorentz-Drude model through the use of Z-transform technique. This algorithm was used to compute the spectral response of infrared bandpass filters which consisted of the openings of cross-shaped structures in a thin gold film. In creating structures, a graphical user interface was built using Matlab development environment. The created structures were then simulated by running the simulation code written in Fortran. It was observed that cross-shaped structures with large center-broadening effect yielded the highest transmission intensity among the structures that were simulated with a transmittance of approximately 80% at the wavelength of 1.2 μm.
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