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分散共聚法制备特殊形态高分子微球的研究 总被引:3,自引:2,他引:3
以聚乙二醇 (PEG)大分子单体为反应性稳定剂 ,在丙烯腈的分散共聚反应中添加少量苯乙烯以形成疏水性核 ,制备得到了亚微米级高分子微球 .透射电子显微镜研究表明 ,该高分子微球具有特异的形态结构 .同时研究了分散共聚体系中各种反应因素对微球形态和直径的影响 ,结果表明 ,苯乙烯单体的添加量、PEG大分子单体的浓度及分子量、混合溶剂的组成对微球直径和形态均有明显的影响 .X 射线光电子能谱 (XPS)研究结果表明 ,微球表面聚集有亲水性PEG链 ,核为疏水的聚 (丙烯腈 苯乙烯 ) ,即形成的特异形态的PEG接枝高分子微球亦为复合型结构 相似文献
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运用不可约张量算法和群理论构造了C3v对称晶场中3d5组念离子的252阶可完全对角化的微扰哈密顿矩阵.用此矩阵计算了Al2O3:Fe3 晶体的光谱精细结构、零场分裂参量(D,a-F)、品体结构,其理论计算值与实验值相符合,并研究了自旋四重态、自旋二重态分别对基态能级的影响,证明了自旋四重态对基态能级的贡献是主要的,自旋二重态对基态能级的贡献虽很小,但却是不可忽略的.进一步研究了SO梢合作用、SS耦合作用对Al2O3:Fe3-品体的光谱精细结构和零场分裂参量的影响,结果发现SO耦合作用是最主要的,SS耦合作用也是不可忽略的. 相似文献
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An efficient general synthetic approach has been developed to synthesize pyrazole-containing bisphosphonate (N-BPs) esters from chromenone derivatives via a sequential two-step reaction in one pot at ambient temperature in good to excellent yields. This protocol provides a new convenient method to prepare lipophilic bisphosphonate precursors with potential activities. 相似文献
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Haishun Liu Yu Wu Guoying Zhang Chunhao Yin Youwei Du 《Journal of magnetism and magnetic materials》2008
The effect of magnetic field amplitude on permeability spectra was studied by using permeability spectroscopy. Results show that the permeability spectra can be greatly affected by magnetic field amplitude—they become complicated under a higher field, which means that the initial permeability increases with an increase of the applied field at first and then decreases with further increase. Meanwhile, another relaxation peak appears and the relaxation frequency increases during the same process. In addition, the permeability is improved significantly over the basic Finemet composition with appropriate substitution of Al for Nb. Moreover, the effect of annealing condition on the permeability spectra as well as the influence of eddy current was also discussed. All these phenomena were explained by using the dynamic magnetization theory and random anisotropy model. 相似文献
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本文研究了自适应设计下广义线性回归的拟似然方程∑ni=1xi(yi-μ(xi′β))=0,其中yi是q维向量,xi是p×q阶随机矩阵,在一定条件下证明了方程的解^βn具有渐进正态的性质. 相似文献
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Jiyuan Duan Biwen Wei Rongjing Yang Chunhao Cai Jiazhen Pan 《Journal of Solid State Electrochemistry》2012,16(2):597-602
How to screen defective lithium ion batteries is of great importance to the producers and consumers, which has been a challenging
problem, since some lithium ion batteries will not present evident different electrochemical behaviors at the initial use
stage. Here, we found that defective lithium ion batteries of zero open-voltage could be differentiated from the good ones
by charging at 1,800 mA (corresponding to 3 C) in combination with in situ infrared thermal imaging technology. During the
charge process, the surface temperatures of the defective lithium ion batteries of zero open-voltage showed at least 10 °C
higher than that of the good one. Results of the charge voltage, charge current, temperature rise, and the analysis of the
cathode strip, separator, and anode strip after full-discharge process showed that this method was effective. 相似文献
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FeSiF66H2O晶体的基态能级和零场分裂参量 总被引:7,自引:3,他引:4
由单晶的中子衍射方法得到FeSiF66H2O的晶体结构,这种晶体结构可以用SiF6-和Fe(H2O)++两个离子来描述,而局域三角对称的Fe(H2O)++离子反映了这种晶体的主要光谱性质利用不可约张量的理论,构成了晶体场和自旋轨道相互作用哈密顿完全对角化矩阵因此,由完全对角化的晶体场和自旋轨道相互作用哈密顿矩阵和电子顺磁共振的理论公式来求出晶体FeSiF66H2O中Fe2+离子的电子顺磁共振零场分裂参量D和Fa并研究了低自旋3L态对电子顺磁共振(EPR)零场分裂参量的贡献结果显示低自旋3L态对电子顺磁共振的零场分裂参量的贡献是较强的理论计算的结果与实验值是相符的. 相似文献