Theoretical study on the structural,mechanical, electronic properties and QTAIM of CrB_4 as a hard material

Using the first-principles calculations based on spin density functional theory(DFT), we investigate the structure,elastic properties, and electronic structure of Pnnm-CrB4. It is found that Pnnm-CrB_4 is thermodynamically and mechanically stable. The calculated elastic properties such as the bulk modulus, shear modulus, Young's modulus, and Poisson's ratio indicate that CrB_4 is an incompressible material. Vicker's hardness of Pnnm-CrB_4 is estimated to be 26.3 GPa, which is in good agreement with the experimental values. The analysis of the investigated electronic properties shows that PnnmCrB_4 has the metallic character and there exist strong B–B and Cr–B bonds in the compound, which are further confirmed by Bader's quantum theory of atoms in molecules(QTAIM). Thermodynamic properties are also investigated.     

表面改性SiO2对SSBR/BR绿色轮胎胎面胶结构与性能的影响

采用4种含不同官能基团修饰剂改性的二氧化硅SiO₂增强溶聚丁苯橡胶(SSBR)/顺丁橡胶(BR)共混体系, 制备了SSBR/BR/SiO₂橡胶纳米复合材料, 研究了其结构与性能. 结果表明, 在混炼胶体系中, 与未改性SiO₂填充的SSBR/BR相比, 改性SiO₂填充的SSBR/BR门尼黏度及结合橡胶含量显著增大, 表明填料-橡胶相互作用显著提高; 硫化焦烧时间缩短60%, 硫化速度增大了35%~40%. 在硫化胶体系中改性SiO₂填充的SSBR/BR具有更大的交联密度, 填料分散性明显改善, 同时也表现出更为优异的物理机械性能, 100%和300%定伸模量提高47%以上, 旋转滚筒式磨耗机法(DIN)磨耗降低5%~12%, 生热降低了约7%~13%, 热空气老化性能提升4%~22%, 代表滚动阻力的tanδ在60 ℃降低8%~13%. 此外, 与SSBR/BR/1165MP硫化胶相比, 用90 mmol/kg氨基改性SiO₂填充的SSBR/BR硫化胶的抗湿滑性能提高6.9%, 表现出最优的综合性能. 填料的良好分散及填料与聚合物的相互作用增强对于提高SSBR/BR/SiO₂胎面胶综合力学性能具有重要意义.     

纳米SiO_2在注水-驱油-油水分离中的界面调控研究进展

表面与界面行为在石油注水开发中广泛存在.功能性纳米二氧化硅具有在油-水-岩石三相界面吸附/聚集/解吸附的独特效应,有望在经济、高效和绿色环保的石油开发技术中得到应用.本文针对注水、注化学剂驱油及采出液的油水分离三个应用方向,以改变注入液-原油-岩石三相之间的界面作用为切入点,介绍了纳米二氧化硅的表面功能化及其在调控油/水/岩石三相界面中的研究进展,总结了其界面调控作用机制.最后,结合课题组研究工作,指出了功能性纳米二氧化硅表面结构调控与应用的研究方向.     

不同形貌纳米α-Fe2O3粉体水热合成及其催化高氯酸铵热分解研究

以Fe2(SO4)3为原料,在不同温度和时间进行水热反应,产物经过600℃下热处理6h,得到了不同形貌的纳米α-氧化铁.通过XRD、SEM、TEM对α-Fe2O3的物相组成、形貌和微观结构进行表征.结果表明,花片状、海胆状、草莓状和哑铃状等多种形貌的产物均由纳米α-Fe2O3颗粒组装而成,纳米颗粒大小为10～50 nm.采用DTA分析了赤铁矿α-Fe2O3对高氯酸铵(AP)的催化性能.结果表明水热反应条件140℃保温4h获得的花片状α-Fe2O3,使得高氯酸铵(AP)热分解温度提前了67.2℃,较其它形貌,催化效果明显.     

紫外光固化胶衣树脂

间苯二甲酸;不饱和聚酯树脂;紫外光固化胶衣树脂     

Theoretical Study of the C-Cl Bond Dissociation Enthalpy and Electronic Structure of Substituted Chlorobenzene Compounds

利用密度泛函(DFT)三种交换/相关函数(B3LYP, B3PW91,B3P86)结合6-31G**和6-311G**基组,计算了13个取代氯苯化合物的键离解能. 结果表明B3P86/6-311G**方法是计算取代氯苯化合物键离解能的可信方法,研究发现C-Cl键的键离解能与所使用的基组和计算方法密切相关,取代基对C-Cl键的键离解能的影响不明显. 研究了目标化合物的前线轨道能级差,并对取代氯苯化合物的热稳定性做了评估.     

Lumped modeling with circuit elements for nonreciprocal magnetoelectric tunable band-pass filter

This paper presents a lumped equivalent circuit model of the nonreciprocal magnetoelectric tunable microwave bandpass filter.The reciprocal coupled-line circuit is based on the converse magnetoelectric effect of magnetoelectric composites,includes the electrical tunable equivalent factor of the piezoelectric layer,and is established by the introduced lumped elements,such as radiation capacitance,radiation inductance,and coupling inductance,according to the transmission characteristics of the electromagnetic wave and magnetostatic wave in an inverted-L-shaped microstrip line and ferrite slab.The nonreciprocal transmission property of the filter is described by the introduced T-shaped circuit containing controlled sources.Finally,the lumped equivalent circuit of a nonreciprocal magnetoelectric tunable microwave band-pass filter is given and the lumped parameters are also expressed.When the deviation angles of the ferrite slab are respectively 0° and45°,the corresponding magnetoelectric devices are respectively a reciprocal device and a nonreciprocal device.The curves of S parameter obtained by the lumped equivalent circuit model and electromagnetic simulation are in good agreement with the experimental results.When the deviation angle is between 0° and 45°,the maximum value of the S parameter predicted by the lumped equivalent circuit model is in good agreement with the experimental result.The comparison results of the paper show that the lumped equivalent circuit model is valid.Further,the effect of some key material parameters on the performance of devices is predicted by the lumped equivalent circuit model.The research can provide the theoretical basis for the design and application of nonreciprocal magnetoelectric tunable devices.     

丁二醇对TiO2纳米晶体水热生长动力学的影响

采用水热法,以丁二醇和水作为混合溶剂,研究了二氧化钛纳米晶体的生长机理.X射线衍射(XRD)结果显示产物为锐钛矿纳米TiO2.用透射电镜(TEM)、高分辨透射电镜(HRTEM)等对不同时间的晶体结构进行表征,发现晶体生长具有明显的奥斯特瓦尔德熟化(OR)特征.颗粒粒径均处于纳米级,其粒径数值随温度增加而变大.丁二醇作为溶剂兼表面活性剂对于纳米晶体的生长起到重要调节作用.采用OR方程,分别对220 ℃、180℃、140℃三个温度下纳米TiO2的生长进行模拟,模拟曲线和实验结果吻合很好,并获得其生长活化能为15.0 kJ/mol.     

稀土对Al2O3-TiC/Fe基金属陶瓷材料性能的影响

以TiC、C、Mn、Ni、Mo、α-Al2O3微粉和还原Fe粉为主要原料,采用粉末冶金方法制备Al2O3-TiC/Fe金属基陶瓷材料.利用管式真空烧结炉(φ150 mm)高真空(2.5 Pa)烧结,烧成温度为1530℃,保温时间90 min.研究探讨不同稀土添加剂对试样吸水率及体积密度的影响,揭示材料的耐磨性能,以及稀土添加剂对试样的显微组织影响.试验表明:在以上条件下,添加0.3;的Y2O3时,Al2O3-TiC/Fe基金属陶瓷材料的吸水率和体积密度达到了最佳状态,分别为0.0310;和6.7770g/cm3,此时材料的耐磨性能得到提高.     

水热合成Cu-Bi2WO6及其光催化性能研究

以Bi(NO3)3·5H2O和Na2WO4·2H2O为原料,NaOH为矿化剂,CuCl2和CuSO4为铜源水热法离子掺杂合成Bi2WO6粉体,并使用XRD、SEM、UV-VIS、XPS对其进行表征,分析了不同铜源离子掺杂Bi2WO6以及掺杂量对所制备样品光催化性能的影响.结果表明,以CuCl2为铜源离子掺杂Bi2WO6的样品粒径减小,吸收边红移.掺杂后的铜以中Cu2和Cu+两种电子形式存在.光催化测试结果表明,以CuCl2为铜源且掺入量为1.5mol;时所制备的Bi2WO6样品的光催化活性最高.