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41.
Fanggao Chang Tao Li Yongxia Ge Zhenping Chen Zhongshi Liu Xiping Jing 《Journal of Materials Science》2007,42(17):7109-7115
DC resistivity, dielectric constant, dielectric loss and positron annihilation spectra of (Ba1−x
Ho
x
)TiO3 ceramics have been measured as a function of holmium concentration x. It has been found that the DC resistivity of (Ba1−x
Ho
x
)TiO3 is strongly dependent on the Ho content: it decreases three orders of magnitude and reaches a minimum at x = 0.4%. Doping with 0.6% holmium increases the permittivity of BaTiO3 by approximately three times (from ∼1,300 to ∼4,000), with only a slight increase in the corresponding dielectric loss. The
local electron density and defect concentration estimated using positron annihilation technique conforms well to the features
found in the dielectric and resistivity measurements. The results have been discussed in terms of a mixed compensation model. 相似文献
42.
文章结合制砖行业原料处理工艺的特点,阐述了姑山矿空心砖厂原料制备过程中所存在的主要问题及相应解决办法.通过对改造前后原料处理工艺的使用效果进行对比,改造后的原料处理工艺更适合于生产线的要求,并且在生产中取得了较好的实际应用效果. 相似文献
43.
高层建筑结构设计特点与剪力墙设计 总被引:6,自引:0,他引:6
围绕高层建筑结构,总结了高层建筑结构设计的特点,提出了剪力墙设计的几个问题,以及高层建筑结构分析和各种体系相对应的方法。 相似文献
44.
从理论上分析了一种基于光正交码(OOC)的多波长光正交码(MWOOC)的性能。给出了一种改进的基于OOC的MWOOC,并且蛤体分析了它的性能。与原MWOOC比较,改进的MWOOC的误码率性能基本相同,但码字数增加很多。 相似文献
45.
46.
47.
Wei-Jun Liu Wei-Dong He Xue-Wu Ge Hua-Rong Liu Mo-Zheng Wang Zheng-Qi Chang 《Materials Letters》2007,61(13):2818-2821
Interfacial-initiated polymerization of styrene (St) was carried out in inversed emulsion with cumene hydroperoxide (CHPO) and ferrous sulfate (FeSO4)/disodium ethylenediaminetetraacetate (NaEDTA)/sodium formaldehyde sulfoxylate (SFS) as the redox initiation system. The water-soluble Fe2+-NaEDTA-SFS acted as the reducing component and the oil-soluble CHPO as the oxidant component of the redox initiation system. Therefore, the primary radicals were produced mainly at the oil/water interface to initiate the polymerization of St. Thus, sub-micrometer hollow polystyrene (PSt) spheres were obtained by one-stage polymerization, which was supported by the techniques of transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). 相似文献
48.
Xia Zhenghan 《中国油气》2006,13(2):30-33
During the 10^th Five-Year Plan Period, Daqing Oil Field entered the late high water-cut period with the reserve production ratio in imbalance. The oil field development became more and more difficult owing to the inadequate substitute resources. Daqing Oil Field Company has made a series of important and new technological achievements to solve those bottlenecks. The oil field has cumulatively achieved a total of technological results, of which eight items are at the State level, 96 items at the provincial and ministerial level, and 1009 items granted with the patent rights. The oil field has developed a family of exploration and development technologies which are world-leading and self-developed with an independent IPR. 相似文献
49.
ChenluSONG WenjianWENG KuiCHENG HaiboQU PiyiDU GeSHEN GaorongHAN JuanYANC JoseM.F.Ferreira 《材料科学技术学报》2003,19(5):495-499
Fluorapatite/hydroxyapatite solid solution has better biological properties than other apatites, especially used as films or coatings. In this work, sol-gel preparation and in vitro behavior of fluorapatite/hydroxyapatite solid solution films on titanium alloy were investigated. Ca(NO3)2-4H20 and PO(OH)x(OEt)3-x were selected as precursors, and hexafluorophosphoric acid (HPFo) was used as a fluorine containing reagent. The Ca and P precursors were mixed with HPFo to keep the Ca/P molar ratio 1.67. The mixtures refluxed for 12 h were used as dipping sols for the preparation of the films. The phase of the films obtained at 600℃ was apatite. The F contents in the films increased with the concentrations of HPF6 in the dipping sols. The solid solution films were shown to have better stability than hydroxyapatite films, and a reasonably good bioactivity in the in vitro evaluation. 相似文献
50.