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911.
简要介绍了全板电镀镍金加工过程中镀金面发白现象及改善措施。特别是针对高位发白(或粗糙)的产生原因和处理过程进行较为详细的描述,并对工艺在此处理过程中存在问题进行了简要剖析。  相似文献   
912.
采用具有水平对称轴的横向各向同性(HTI)模型研究裂缝性油气藏,P波振幅随炮检距和方位角变化(AVOA),表现出较强的方位各向异性特征。本文基于Ruger提出的HTI介质模型的P波反射系数公式,利用由基准测线和另外两条与之呈45°、90°测线的P波反射系数的相对差异估算裂缝方位;同时引入小生境遗传算法,对基准测线和与之呈90°测线的P波反射系数差进行反演,得到了较高精度的纵、横波波速比和Thomsen各向异性参数。  相似文献   
913.
Three kinds of carboxymethyl chitosan/β-cyclodextrin microspheres loaded with theophylline were prepared by spray drying intended for pulmonary delivery. Mucociliotoxicity, permeation rate, and drug release characteristics of the product were investigated. The microspheres obtained by spray drying were found to be spherical with smooth or wrinkled surfaces. The mean particle size was between 3.39 and 6.06 µm. The microspheres demonstrated high product yield (43.7-50.2%), high drug loading (13.7-38.1%), and high encapsulation efficiency (86.9-92.8%). FT-IR indicated that there were interactions of theophylline with carboxymethyl chitosan matrix. Further studies on mucociliotoxicity and permeation confirmed that microspheres had better adaptability and high permeation rate. In vitro drug release from the microspheres was not related to the drug/polymer ratios.  相似文献   
914.
Six triorganotin(IV) complexes of the type {(R3Sn)2[C3S3(COO)2]}n (R = C6H5 1; n-Bu 2; PhCH2 4; p-F-PhCH2 5; o-F-PhCH2 6) and {(R3Sn)2[C3S3(COO)2]}n·[EtOH] (R = Me 3) have been synthesized by the reaction of bis(carboxymethyl)trithiocarbonate with triorganotin(IV) chloride in the presence of sodium ethoxide. All complexes were characterized by elemental analysis IR, 1H, 13C and 119Sn NMR spectroscopy. Except for 4–6, all complexes were also characterized by X-ray crystallography. The X-ray date revealed that complexes 1–3 show two-dimensional network polymeric structure in which the geometries of tin atoms are trigonal bipyramid with the axial positions occupied by carboxylic oxygen atoms.  相似文献   
915.
Cubic boron nitride (c-BN) crystals were synthesized in conditions of high temperature and high pressure (HTHP) when different kinds of bonded water were respectively added into the system of h-BN–Mg. All bonded water used in this work could reduce the temperature of growing c-BN compared to that in the system of h-BN–Mg. The c-BN color could change from black to yellow when certain amounts of bonded water, such as NiSO4·6H2O and CuSO4·5H2O, Mg(OH)2, were added. However, c-BN color remained black no matter how much bonded water, such as NiCl2·6H2O, CuCl2·2H2O, and SnCl2·2H2O, was added. The bonded water can be classified into Chlorine-containing bonded water (Cl-BW) and Chlorine-free bonded water (ClF-BW) according to their different characters and effects on the synthesized c-BN color.  相似文献   
916.
Hydrothermal Synthesis of Magnesium Aluminate Platelets   总被引:1,自引:0,他引:1  
Magnesium aluminate (MgAl2O4) platelets were first synthesized by hydrothermal treatment of γ-AlO(OH) in a magnesium nitrate aqueous solution at 400°C. The platelets are 100–200 nm in width and 25 nm in thickness. The influence of temperature, the anions of the magnesium salt, the amount of magnesium salt, and precursor pH on the formation of such structure was investigated. The experimental results indicated that the anions of the magnesium salt and precursor pH could have a significant influence on the growth of MgAl2O4. MgAl2O4 formation followed the in situ transformation mechanism, which was the reason why the MgAl2O4 crystallites had a platelet morphology.  相似文献   
917.
In this work the synergistic effects of microwave (MW) irradiation induced oxidation processes and CoFe2O4 were studied for the degradation of brilliant green (BG) from aqueous solutions. Under the optimum condition, the ratio of solid to liquid was 1:167 (0.3 g CoFe2O4 mixed with 50 mL of 20 mg L−1 BG solution), MW power 600 W, and the time of the irradiation 2 min. And the decolorization rate could reach up to 100%. Further investigation showed that BG was degraded by MW-induced oxidation combined with CoFe2O4 surface adsorption. The CoFe2O4 could increase the efficiencies of MW degradation and be used repeatedly. The experimental results indicated that the method of MW degradation BG in the presence of CoFe2O4 could reduce reaction time and increase product yield.  相似文献   
918.
919.
丙烯酸二甲氨基乙酯的合成   总被引:6,自引:0,他引:6  
以丙烯酰氯与二甲氨基乙醇为原料 ,乙醚为溶剂 ,过量的二甲氨基乙醇为缚酸剂合成了丙烯酸二甲氨基乙酯。较佳实验条件为 :丙烯酰氯 /二甲氨基乙醇 /乙醚 (物质的量比 ) 1∶2 .0 5∶5 .6 ,反应温度 5℃ ,反应时间 4h ,w(吩噻嗪 ) 0 .5 0 %,产物为无色透明液体 ,相对密度 0 .943 1( 2 0℃ ) ,折光率为 1.435 2 ,收率大于 91%。  相似文献   
920.
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