高介电常数TiO2纳米晶的表面态研究

将钛酸四丁酯和硬脂酸在熔融状态下混合均匀后置于冷水浴中,使其凝固成凝胶,通过控制烧结过程中氧气的含量,成功地制备出粒度均匀、介电性能好的纳米晶TiO2.通过采用X射线光电子能谱和表面光电压谱对纳米晶TiO2表面状态的分析发现,材料表面存在大量的氧空位缺陷,暴露在粒子表面上的主要是一些金属Ti4+.纳米材料的这种表面状态对其极化性质具有重要的影响,使其在接近静态条件下的低频介电常数远大于常规材料的介电常数.     

Rapid Fabrication of Hollow SiO2 Spheres with Novel Morphology

The hydrolysis of tetraethoxysilane (TEOS) occurred on the surface of poly(methyl methacrylate) (PMMA) microshperes immediately after these microshperes were prepared in TEOS. Micron-sized hollow SiO2 spheres were obtained by calcination of the coated PMMA microshperes. It was found that the final hollow spheres were constituted by small SiO2 particles.     

氰根桥连的异金属配位聚合物{[Ni(pn)2][Fe(CN)4(bipy)]}2·3H2O(pn=1,3-丙二胺,bipy=2,2′-联吡啶)的合成与结构

以[Fe(CN)₄(bipy)]^2-为建筑块和[Ni(pn)₂]²⁺在水溶液中反应,合成了{[Ni(pn)₂][Fe(CN)₄(bipy)]}₂·3H₂O(pn=1,3-丙二胺)。通过X-射线单晶衍射确定了其晶体结构。该配合物属单斜晶系,P2₁/n空间群,晶胞参数为:a     

溶液酸度和反应温度对CaMoO4薄膜电化学制备的影响

本工作研究了恒电流电化学技术制备CaMoO₄薄膜工艺中，溶液酸度和反应温度对薄膜形成的影响。结果表明，酸度会影响薄膜的生长时间和光致发光特性，在较低酸度沉积薄膜时，容易造成薄膜的团簇生长和不确定相的形成；适当升高反应温度会加快晶粒的生长、提高薄膜的纯度、增加薄膜发射光谱的相对强度。在CaMoO₄薄膜电化学制备工艺中，溶液pH值控制在12.0附近和反应温度控制在60 ℃的左右比较好。     

河口水体中痕量稀土元素的共沉淀预富集-电感耦合等离子体质谱法测定研究

建立了氢氧化铟共沉淀预富集 -电感耦合等离子体质谱法测定河口水体中痕量稀土元素的方法。实验结果表明 ,在80mg·L -1的In3 +和pH9.5的实验条件下 ,在1.0L水样中添加5.0～200.0ng的混合稀土标准溶液 ,均能定量回收 ,回收率在82.2 %～106.9 %之间。方法的分析流程空白为0.04(Tb)～10.17(La)ng·L -1,检出限在0.17(Yb)～1.46(La)ng·L-1之间 ,精密度 (RSD ,n=3)小于11.7 % ,可满足河口淡水和海水样品中的痕量稀土元素定量分析的要求     

聚天青A膜修饰电极的电化学特性及其对亚硝酸根的电催化性能

在玻碳电极上以循环伏安法制备了聚天青A膜修饰电极(PAAE) ,天青A能够在玻碳电极上形成稳定的聚合膜 ;通过正交试验确定了电聚合天青A的最佳条件 ,研究了该修饰电极的电化学特性 ,并讨论了其对亚硝酸根的电催化还原作用 ;结果表明 ,亚硝酸根在PAAE上有很好的电流响应 ,催化峰电流与亚硝酸根浓度在1.0×10-5 ～4.0×10-3 mol/L之间呈良好的线性关系     

高聚物亚浓溶液区标度律的蒙特卡洛模拟

利用蒙特卡洛模拟方法对线形链和星形键在亚浓溶液区的标度律作了验证与讨论。我们的计算结果证明线形链渗透压Π与体积分数Φ在亚浓溶液区的标度规律是与德热纳的理论结果相一致的。同时还证明了星形链在亚浓溶液区具有与线形链相同的标度行为。     

对苯二甲酸二甲酯(DMT)与乙二醇(EG)的酯交换反应模拟动力学

Based on the method of ε-NTU, a mathematical modeling of ester-interchange reaction for dimethyl terephthalate (DMT) with ethylene glycol (EG) by acetate system was simulated, and, in addition, the corresponding kinetic equation is obtained by using the theoretical method of simulation. That is,-(dc)/(dt)=kc(c+k')where:-(dc)/(dt)= the reaction rate of the monomer, C -concentration of the monomer, θ-Suitable parameterk,k'-constant (k'=θ/k)The experimental results have showed that the ester-interchange reaction is a reaction neither first order or second order nor third order,but it is a reaction of secondary linear type. Yamanis^[2] doubted the correctness of the method that has been proved.Moreover,we have suggested the physical meaning of parameters.     

接触角法研究医用聚醚聚氨酯材料表面自由能与界面自由能

<正> 表面性质在医用材料与生物体的相互作用中起着至关重要的作用,如血液相容性材料的表面对血细胞具有吸附、变形、凝血、溶血等作用。表面能和界面能是医用材料的重要研究内容之一,材料的表面能及其极性与非极性分量在影响或控制材料与生物体的相互作用之面一直是医用材料的重要课题。Raier曾提出当材料的临界表面张力在20-30erg/cm~2时,血液相容性好,也有人认为,血液与材料的界面自由能趋于零时,才能     

一种新型侧链液晶聚合物的喇曼光谱研究

The Raman scattering on a novel liquid crystal side chain polymer, poly-2,5-bis (p-meth-oxybenzoyloxy) styrene, has been performed. We observed that the characteristic Raman sp-ctra of the vinyl group in the monomer changed much deeply in the polymer, especially for the Raman line correponding to the C=C of the vinyl group which disappeared completly in the polymer. Contrast with that, the Raman spetra of the rest group did not present any substantial difference between the monomer and the polymer. These experimental facts show-ed that the vinyl group of the monomer was tranfered to the polymeric backbone while the chemical structure of the mesogenic unit in the monomer remained after the polymerization,and also conformed that it was successful in the synthesis of a liquid crystal side chain plymer without a flexible spacer between the mesomorphic unit and the molecular main chain.