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31.
本文在高T_c超导体Bi_1Sr_1Ca_1Cu_2O_y常压制备的基础上,研究了热压烧结和冷压处理对其形成、结构及超导电性的影响,并与常压结果进行了比较。结果表明,高压可以使样品的合成时间缩短,合成温度降低。但同时它也抑制了晶格参数较大的相(高T_c相)的形成,使小晶格参数的杂相含量增多。对于提高样品的超导电性而言,1.5 GPa是一个较好的压力点。 相似文献
32.
Gap and InP nanocrystals were synthesized from Na3P and GaCI3 at low temperature (80–100°C) and atmospheric pressure. The samples were characterized by XRD and TEM measurements. The surface
reactivity of Gap nanocrystals was studied by heating in N2. The weight of the nanocrystals increased at the temperature between 370°C and 480°C. It can be concluded that N, molecule
was absorbed and reactivated on the surface of Gap nanocrystals. Keywords: gallium phosphide, indium phosphide, nanocrystal,
surface reactivity. 相似文献
33.
Lattice-matched InGaAs/lnP heterostructures have been grown by using metalorganic vapor phase epitaxy (MOVPE) with tertiarybutylarsine
(TBAs), tertiarybutylphosphine (TBP) as the group V sources. The results of X-ray diffraction on InGaAs/lnP single herterostructure
show that there is a compressive-strained interfacial layer at the InP-to-InGaAs interface. X-ray diffraction of InGaAs/ InP
superlattices is successfully simulated by using the same interfacial layer. TBAs purging of InP surface has a significant
influence on the interfacial strain. A novel gas switching sequence, which switches group III to the run line earlier than
TBAs, is proposed to reduce this interfacial strain. As a result, the average compressive strain of superlattices decreases,
and a blue shift of photoluminescence ( PL) peak energy and narrowing in PL width are obtained. 相似文献
34.
Na_(1.0)Zn_(1.62)Si_(1.38)O_(4.84)·0.6H_2O的水热合成及离子导电性质崔得良,傅戈妍,庞广生,徐秀廷,冯守华,徐如人(吉林大学无机水热合成开放研究实验室,长春,130023,内蒙古民族师范学院化学系)关键词水热合成,... 相似文献
35.
以十二烷基硫酸钠(SDS)的水溶液为造孔剂,用溶剂热压方法制备了大孔径的ZnO多孔纳米块体,并进一步考察了添加聚乙二醇400(PEG-400)对样品中孔道的影响. 实验发现,向十二烷基硫酸钠(SDS)的水溶液中加入聚乙二醇400组成共溶剂后, 制备的ZnO多孔纳米块体的孔径大幅度减小,比表面积和孔隙率也明显降低,但孔径的均匀性显著提高. 相似文献
36.
37.
利用水热法合成了立方氮化硼(cBN). 通常水热法制备的氮化硼样品是立方氮化硼(cBN)和六方氮化硼(hBN)及其它晶相的混合物,这限制了该方法的应用前景. 文中利用立方氮化硼在特定反应条件下的自发团聚现象,成功地发展了一种使混合物中的立方氮化硼在反应过程中自发纯化的新方法. 提高原料浓度和反应温度,有利于获得更大粒径的立方氮化硼和尺寸分布更均匀的团聚颗粒,提高搅拌转速来改善溶液的均匀性也有同样效果;而提高反应压力则会导致相反的结果. 文中也探讨了自团聚现象在生长大尺寸立方氮化硼晶体以及非均相合成中的潜在应用价值. 相似文献
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39.
用溶液电化学方法及固态电极方法研究了Na5YSi4O12(NYS)与K^+和Ag^+的离子交换性质,对离子交换后得到的KNYS和AgNYS样品的结构、密度和离子导电性质进行了表征。与其它离子交换方法相比,上述方法可获得较高的离子交换度,而且元素分析结果与密度测试结果符合良好。 相似文献
40.
磷化镓纳米粒子的固氮 总被引:2,自引:0,他引:2
Under mild ambient conditions gallium phosphide (GAP) nanoparticles were employed to carry out the reduction of nitrogen. By using Nessler's reagent ammonia was detected in the slurry where the aggregated GAP particles were suspended in water and bubbled by pure nitrogen. Dependence of the concentration of ammonia upon bubbring time, velocity of the flow of nitrogen, and dosage of GAP particles was investigated. In comparison with the original GAP nanoparticles, the Raman scattering of the GAP particles undergoing the process of nitrogen fixation reveals that two sharp lines at 138 and 182 cm^-1, respectively, emerged from the broad continuum around 100-200 cm^-1. These two lines might be assigned to the translational motions of ammonia adsorbed on the surface of the GAP particles. An assessment of the infrared spectra of the two GAP particles led to the conclusion that the environment of the two H2O molecules was not identical. Analysis of the electron spin resonance results showed that the structure defect, gallium self-interstitial, was not involved in the nitrogen fixation of the GAP nanoparticles. 相似文献