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141.
本文介绍溶胶-凝胶法制备均匀PbZr-Ti-B-Si凝胶玻璃,并通过适当热处理在凝胶玻璃中原位生长Pb(Zr;Ti)O3微晶的新工艺·利用IR谱考察了凝胶玻璃中的元素键合结构随温度的变化.结合热分析和XRD;SEM技术,研究了Pb(Zr,Ti)O3微晶在凝胶玻璃中的生长过程及该材料的结构特点.发现Pb2(Zr,Ti)2O6+x立方焦绿石介稳过渡相的纳米微晶首先出现于该体系中,并在更高的温度下先后完全转变成三方和四方Pb(Zr,Ti)O3钙钛矿相.电子显微观察结果表明,该工艺制备的Ph(Zr;Ti)O3玻璃陶瓷具有均匀的细晶结构. 相似文献
142.
This paper deals with the application of continuous thermodynamics to light and heavy oil systems using the Peng- Robinson equation of state. The composition of the high molar mass components in a reservoir oil is described by a continuous distribution function of some characterizing quantity, e.g. molar mass or boiling temperature. Numerical Gaussian quadrature methods are used to generate pseudo-components and their mole fractions from distribution data. Several examples are presented for phase equilibria of solvent/crude oil systems. The results showed that semi-infinite distribution functions, such as the Γ function, cannot be applied to all cases, e.g. dew point calculations. The Gauss- Legendre quadrature method coupled with spline fitting worked best for heavy oil systems. 相似文献
143.
非反应性共聚物增容剂的作用 总被引:8,自引:6,他引:2
游长江 《高分子材料科学与工程》1993,9(2):1-5
简述了共聚物增容剂在聚合物熔融共混物中的作用方面的研究进展。阐述了A-B、A-C和D-E型非反应性共聚物增容剂。重点介绍了增容剂的分子量、用量对聚合物共混物的界面张力、相畴尺寸和聚结的影响。 相似文献
144.
J. W. Huang J. M. Ryan K. L. Bray T. F. Kuech 《Journal of Electronic Materials》1995,24(11):1539-1546
The defect engineering in metalorganic vapor phase epitaxy InxGa1-xAs and InP by controlled oxygen doping using diethyl aluminum ethoxide (DEALO) was developed in this study. DEALO doping has
led to the incorporation of Al and O, and the compensation of shallow Si donors in InxGa1−xAs: Si with 0 ≤ x ≤ 0.25. With the same DEALO mole fraction during growth, the incorporation of Al and O was found to be independent
of x, but the compensation of Si donors decreases with increasing In content. Deep level transient spectroscopy analysis on
a series of InxGa1-xAs: Si. samples with 0 ≤ x ≤ 0.18 revealed that oxygen incorporation led to a set of deep levels, similar to those found in
DEALO doped GaAs. As the In composition was increased, one or more of these deep levels became resonant with the conduction
band and led to a high electron concentration in oxygen doped In0.53Ga0.47As. Low temperature photoluminescence emission measurements at 12K on the same set of samples revealed the quenching of the
near-band edge peak, and the appearance of new oxygen-induced emission features. DEALO doping in InP has also led to the incorporation
of Al and O, and the compensation of Si donors due to oxygen-induced multiple deep levels. 相似文献
145.
146.
The quaternary alloy InAs1−x−ySbxPy, lattice-matched to InAs, is a promising material for the production of infrared light sources for the detection of gases
in the 2–4 μm region of the spectrum. In this work, thermodynamic phase equilibrium calculations have been carried out to
determine the compositions required for liquid phase epitaxial growth and the extent of the miscibility gap in the solid material.
For high band gap materials, the desired growth temperature is found to be intermediate between a low temperature required
to grow P-rich solids and higher temperatures required to avoidspinodal decomposition. Conventional LPE growth at an intermediate temperature of 583°C is found to produce good material with high
luminescence efficiency and excellent optical characteristics. Problems with phosphorus loss from the melt are also discussed
and lower growth temperatures are found to considerably reduce this problem. Growth in the metastable region between the binodal
and spinodal lines has been achieved with the production of phosphorus-rich solids with concentrations up to y = 0.445. 相似文献
147.
在制作付里叶计算全息过程中,加入适当的二次位相因子,使此种全息图在相干光照明下就可预定的位置上只再现一个像,省略了过去丙现此种计算全息图必要的付里叶透镜,并且使两个互为共轭像分离,从而拓宽了此种计算全息的应用领域,实验结果与理论分析相符。 相似文献
148.
相转移法制备高纯超细TiO2技术研究 总被引:9,自引:0,他引:9
报道了用相转移法制备高纯超细TiO2的新技术;探讨了Ti(Ⅳ)从有机相转移到水相发生水解反应的机理 ;通过TG-DTA分析以及XRD物相分析对水解产物的组成、热分解机理,晶型转变规律进行了研究,建立了水解产物焙烧的最佳温度。 相似文献
149.
The growth of nominally undoped GaSb layers by atmospheric pressure metalorganic vapor phase epitaxy on GaSb and GaAs substrates
is studied. Trimethylgallium and trimethylantimony are used as precursors for the growth at 600°C in a horizontal reactor.
The effect of carrier gas flow, V/III-ratio, and trimethylgallium partial pressure on surface morphology, electrical properties
and photoluminescence is investigated. The optimum values for the growth parameters are established. The carrier gas flow
is shown to have a significant effect on the surface morphology. The optimum growth rate is found to be 3–8 μm/ h, which is
higher than previously reported. The 2.5 μm thick GaSb layers on GaAs are p-type, having at optimized growth conditions room-temperature
hole mobility and hole concentration of 800 cm2 V−1 s−1 and 3·1016 cm-3, respectively. The homoepitaxial GaSb layer grown with the same parameters has mirror-like surface and the photoluminescence
spectrum is dominated by strong excitonic lines. 相似文献
150.