Dynamics of a magnetic nanowire suspended in Twisted Nematic Liquid Crystal under magnetic field

液晶是一种具有各向异性的复杂流体，它能对置于其中的悬浮颗粒产生力和力矩作用，这种现象在普通的溶液中是不存在的。向列相液晶由长棒状分子所构成，其状态可用分子长轴朝某一方向近似同一排列来描述。在向列相液晶和另一边界的交界处，液晶分子和边界表面之间的相互作用使得液晶分子有一个能量最优的排列方式。如果与液晶相接触的表面不是平表面，如向列相液晶中的球形和圆柱形悬浮颗粒表面，边界条件对液晶分子排列方式的限制将打破其原有的有序排列，使得液晶的弹性能增加。因此悬浮颗粒会受到液晶所施加的弹性力。对于形状各向异性的悬浮颗粒，如长圆柱形的纳米金属丝和碳纳米管，会因引起液晶指向矢形变，增加体系弹性能而受到液晶施加的弹...Liquid crystal, as one type of complex fluids, will impose elastic forces and torques on inclusions, which are not found in ordinary liquids. Nematic liquid crystal is composed of rod-like molecules and is characterized by the alignment of molecular long axes along a particular direction. At the interface between liquid crystal and other surfaces, anchoring interactions between liquid crysta...学位：理学硕士院系专业：物理与机电工程学院物理学系_理论物理学号：1982008115298

The Phase Transition of Nematic Liquid Crystal Cells Bounded by Surfactant-Laden Interfaces

National Science Foundation of China [50873083, 10974162]Taking into account the surface-coupling strength effect, we discuss the phase transitions of a finite thickness cell bounded by surfactant-laden interfaces in a magnetic field perpendicular to the substrate and it is compared with that of a semi-infinite system. It is found that the larger the thickness, the closer the three-dimensional phase transition surface of the finite system to that of the semi-infinite one. The simulation also shows that when a magnetic field is applied to a nematic semi-infinite sample, an orientational phase transition first takes place close to the interface and then extends to the inner space as the temperature increases

Reaction Mechanism of V(Ⅳ)/V(Ⅴ) Redox Couple at Graphite Felt Composite Electrode Bonded with Conductive Carbon Plastic

应用循环伏安、极化曲线和交流阻抗等电化学方法研究了V(Ⅳ)/V(Ⅴ)电对在石墨毡复合电极上反应的速控步骤.结果表明,V(Ⅳ)/V(Ⅴ)电对在石墨毡电极上的反应属准可逆过程,且氧化过程包含有后置化学转化步骤;该过程Tafel斜率的实验值为0.124,而理论计算的,以电化学步骤作为控制步骤的Tafel斜率约0.12,两者吻合很好,表明该氧化过程受电化学步骤控制;以等效电路拟合不同极化电位下的交流阻抗,得出该电化学反应阻抗远大于其他阻抗,意味着电化学过程可能是电极反应的控制步骤,与实验得到的极化曲线分析结果相一致.The rate-determining step of V(Ⅳ) /V(Ⅴ) redoxreaction was investigated at graphite felt(GF)composite electrode by various techniques: cyclic voltammetry,polarization curve and impedance spectroscopy.Cyclic voltammetry analysis indicated that V(Ⅳ) /V(Ⅴ) redox reaction at GF electrode is quasi reversible.Acertain chemical reaction step is suspected to follow the electron transfer step of this reaction.The Tafel slopevalue(0.124) obtained from the polarization curve agrees well with theoretical value(0.12),which supposingthe electron transfer step was the rate-determining step.Impedance Spectroscopies at various potentials werestudied and simulated by equivalentcircuits.The impedance value of the electron transfer step modified is greatlyhigher than the others,which shows that the electron transfer step is the rate-determining step.This further con-firms the conclusion obtained by polarization curve test.作者联系地址：中南大学化学化工学院,中南大学化学化工学院,中南大学化学化工学院,中南大学化学化工学院,中南大学化学化工学院 湖南长沙410083,湖南长沙410083,湖南长沙410083,湖南长沙410083,湖南长沙410083,中科院物理所,北京100083Author's Address: 1.School ofChemistry and Chemical Engineering,Central South University,Changsha410083,Hunan,China;2.Institute ofPhysics,Chinese Academy ofSciences,Beijing100080,Chin

Dynamics of a Magnetic Nanowire in Twisted Nematic Liquid Crystal

液晶中的纳米颗粒悬浮体系由于其独特的性质引起了极大的关注.采用保角变换法和等效电容法,对悬浮于扭曲型向列相液晶盒中的磁性纳米金属丝在外加恒定磁场下的动态响应行为进行了研究,并将理论计算结果与实验结果作比较.通过比较发现,理论计算结果与实验结果符合得很好.Systems of nanoparticles suspended in liquid crystal have raised great interest because of their unique property and the potential as novel materials.The dynamic behaviors of a nickel nanowire suspended in a twisted nematic liquid crystal cell under constant magnetic field are analyzed,using the methods of equivalent capacitance and conformal mapping.A comparison with experiments shows that our calculation agrees well with the experimental results.国家自然科学基金项目(50873083;10974162

Support Effect of Hydrotalcite Supported Au25 Nanoclusters for Chemoselective Hydrogenation of 3-Nitrostyrene.

Support Effect of Hydrotalcite Supported Au25 Nanoclusters for Chemoselective Hydrogenation of 3-Nitrostyrene

ZnO形貌对金催化剂氢气活化的影响

Hydrogen activation on Au nanoparticles supported on ZnO with different crystal structure

Hydrotalcite (HT) Supported Thiolated Au25 Nanoclusters for Chemoselective Hydrogenation of Functionalized Nitroarenes.

Hydrotalcite (HT) Supported Thiolated Au25 Nanoclusters for Chemoselective Hydrogenation of Functionalized Nitroarenes