Sol-gel method is used for the formation of Pb0.499Sr0.499TiO3 (PST)thin films. The initial films were prepared with spin coating sol solution on silicon wafer and drying at room temperature and then heating coated dry sol film at 400°C for 10min. This process was repeated for 1-4 times to obtain 4 initial films with different thicknesses. The 4 initial films were annealed at 700°C for 2h to obtain PST ceramics films. The morphologies of the surface and cross-section of PST films were observed with a scanning electronic microscope (SEM). The phase structures of PST films were analyzed using X-ray diffraction meter (XRD). Experimental results show that PST film prepared by coating sol on silicon with different thicknesses can be high smooth,uniform and compact film.
In this paper, effect of oxygen partial pressure on formation of Fe2O3 nanostructure during Thermal Oxidation was studied. Fe2O3 nanostructure was formed by controlling oxidation conditions (Po2) and using the method of thermal oxidation. To begin with, a piece of pure iron in a ceramic crucible was put in the tube furnace (SYS-G-Z-13). Next the metallic Fe was oxidized at 500°C for 4 hours, under different oxygen partial pressure including pure argon (Po2 = 0atm), air Po2 = 0.21atm) and pure oxygen (Po2 = 1atm) to produce nanostructure, respectively. The surface morphology of the oxidized specimens was observed by SEM. The crystalline structure of the nanostructure was determined by transmission electron microscope. The experimental results show that the density of nanosheets increases with increasing oxygen partial pressure.
In order to support well some promising dual-use core technology integration items with limited resources, scientific and effective value evaluation model should be constructed by governments. Based on the characteristics of such technology integration project, we build a value evaluation system for dual-use core technology integration, which includes social effects, economic results, technical value, and possibility for technology to be transformed into products etc. as major component. And then, such project evaluation model is established by using gray theory and hierarchy analysis method. By using a case analysis, it reveals and verifies further the operational process of this evaluation model. This model is scientific and feasible. Since it is not perfect, some research works on this model should be done further in future.
The process of producing active vacancies on a hydrogen-terminated diamond surface is the most important rate-limiting stage in CH4/H2 and CH4/H2/CO2 atmospheres. Hydrogen atom and the hydroxyl group can bone to the hydrogen atom on the diamond surface and create an active vacancy. Density functional theory (DFT) was used to study the extraction reaction by two reactants both hydrogen atom and the hydroxyl group. The result indicated that the hydroxyl group could reduce the energy required for diamond surface activation. What is more, the activation rate of the surface by the hydroxyl group was livelier at low temperature, while the activation rate of the hydrogen atom predicts on the contrary. The scanning electron microscope (SEM) and Raman spectra demonstrated that the introduction of CO2 in the CH4/H2 atmosphere could reduce the deposition temperature and raise the deposition rate at low temperature.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.