磁场对双轴分子液晶的影响

在分子场近似下,研究分子双轴性对向列相液晶在各向同性相最低过冷温度的影响,以及对临界磁场的影响。当外加磁场大于临界磁场时,不发生向列相－各向同性相相变。理论结果表明,通过考虑分子双轴性,最低过冷温度Ｔ＾＊与相变温度Ｔｃ的比值向实验值靠近。随着分子双轴性的增加,临界磁场很快下降。     

无摩擦基板上液晶薄层的分子场理论

采用分子场近似，通过Ｌｅｂｗｏｈｌ－Ｌａｓｈｅｒ模型研究无摩擦基板上的液晶薄层，给出了出现向列相对液晶薄层中的子分子取向状态的向列相－各向同性相转变，讨论了基板诱导的取向序（包括双轴序）以及介面区中的双轴一单轴相变。     

静电场对向列相液晶的影响

用统计物理的方法讨论了外加静电场对向列相液晶的影响。结果表明，电场诱导的向列相取向序参量、双折射和向列相—各向同性相的相变温度的改变是场强的偶函数，在电场较弱时与场强平方成正比。     

表面极化的二粒子集团理论

应用二粒子集团理论研究了基板对极性分子构成向列相液晶的作用。假定分子质心固定在简单立方晶格的格点上,分子间存在色散作用和偶极相互作用,与基板相接触的一层分子受到表面作用,在二粒集团近似下导出了分子取向分布函数所满足的方程,并用迭代方法求解,得到如下结论：在向列相液晶与固体基板相接触的界面上,会出现极化层,当基板的表面作用足够强时,界面极性序几乎独立于温度,不受体液晶相变影响。     

弹性键相连的双矩形板液晶分子系统的相变

根据分子间简单相互作用能,利用平均场理论,得到双矩形板液晶分子系统在温度和分子结构参数平面内随着弹性键强度的增加出现的4类相图:第一类相图(弹性键强度最小)中只有一个直接由各向同性相进入双轴向列相的Landau点,从单轴相到双轴向列相的相变为二级相变;第二类相图中Landau点扩展为Landau曲线,正的单轴相范围增加,负的单轴相范围缩小,出现了从单轴相到双轴相的一级相变;第三类相图中,Landau点同样扩展为Landau曲线,但负单轴相区域消失;第四类相图中(弹性键强度最大),Landau曲线范围反而缩小。     

平行平板间向列相液晶中的分子短程关联

用二粒子集团变分理论研究了平行平板间的向列相液晶系统，理论中考虑了分子短程关联。平板使得表面分子趋向于垂直平板排列。对由２０个分子层组成的液晶薄层进行了数值计算。给出了典型表面势强度下的向列相—各向同性相转变温度以及序参数对分子层的依赖关系。     

苯基单分子器件I-V特性的研究

采用紧束缚近似的方法,研究了由单苯基分子构成的三端器件的I-V特性。所得结果近似表现出了MOS(Metal-Oxide-Semiconductor)器件的电学规律;同时模拟并讨论了该器件的I-V特性随温度变化的规律,发现:电流幅值随门电压的增大而增加,温度对电流幅值有重要影响。所得结论为分子器件和纳米器件的开发,提供了理论基础。     

蓝相Ⅲ到各向同性相相变比热与约化温度的关系

通过手性液晶的Landau-Ginzburg-de Gennes理论和Lech Longa的简化手性模型理论在四阶累积展开的帮助下给出蓝相Ⅲ到各向同性相相变系统自由能高阶项的计算结果,分析了相变比热与约化温度的关系,得出了蓝相Ⅲ到各向同性相的相变结束于一临界点,从而说明蓝相Ⅲ为各向同性相。     

PDLC膜光透射率温度特性的研究

用相互独立、大小相同的球形液晶微摘均匀分散在聚合物基质中形成的聚合物分散液晶（ＰＤＬＣ）膜的物理模型,计算了ＰＤＬＣ膜光透射率随温度的变化。结果表明在各向同性相时透射率随温度变化较缓慢,在向列相时透射率有一峰值。理论结果与实验值相符。     

从平衡分凝系数计算二元同形系相图

本文从液固相平衡出发,推导出二元同形系液固相变的平衡分凝系数与其等效相变潜热的关系,又从二元同形系的分子间作用势和相图的对称性得到等效相变潜热的近似表达,从而导出计算二元同形系相图的分凝系数法.用分凝系数法计算了(Hg,Cd)Te赝二元同形系相图,所计算的液固相点温度与实验值的拟合度与用较复杂的热力学方法计算的结果相近.     

近晶相液晶的连续体理论

从层变形是分子间作用结果的观点考虑，依据近晶相液晶的对称性，推导出了一种新的近晶相连续体理论，与Ｇｅｎｎｅｓ理论不同，该理论用分子指向矢ｎ→来描述液晶的自由能，从而使理论表述从物理上讲更易理解。最后给出证明，论证这两种表述在本质上是可互换的。     

Perovskite Oxides for Cathodic Electrocatalysis of Energy-Related Gases: From O2 to CO2 and N2

The oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO₂RR), and nitrogen reduction reaction (NRR) are important cathodic reactions for renewable fuel production and energy conversion technologies. However, the sluggish kinetics of these reactions hinders the practical applications of the relevant technologies. Perovskite oxides, a promising family of catalysts with great flexibility in composition and structure engineering, exhibit versatility in electrocatalysis of these reactions. In this review, beginning with a brief introduction on the fundamentals of ORR, CO₂RR, and NRR, the mechanistic understanding of the electrocatalysis by perovskite oxides is discussed based on both molecular orbital and band theories. The recent advances of perovskite oxide-based electrocatalysts for ORR, CO₂RR, and NRR are then highlighted. Strategies for developing perovskite oxide-based ORR catalysts are emphasized with representative examples, intending to draw on the experience of developing ORR catalysts to both CO₂RR and NRR catalysts. Finally, perspectives on the perovskite oxide-based electrocatalysis are discussed by paying particular attention to the practical applications and future development of perovskite oxide-based catalysts.     

Emergence of Multispinterface and Antiferromagnetic Molecular Exchange Bias via Molecular Stacking on a Ferromagnetic Film

Heterointerfaces may exhibit unexpected physical properties distinct from intrinsic properties of component materials. In particular, metal–organic interfaces can drive unique interfacial spin moments, which are often called molecular spinterface. Here, van der Waals stacking of molecular layers may lead to variations in the intra/interlayer exchange coupling resulting in multiple ground states, which is highly desired for multifunctional magnetic devices. In this report, the emergence of molecular multispinterface of paramagnetic cobalt‐octaethyl‐porphyrin (CoOEP) layers in a Fe/CoOEP heterostructure is demonstrated through the interfacial layer and a successive antiferromagnetic molecular spin chain. The disentangled interfacial ferromagnetic spins lead to multiple magnetic ground states and behave as additional spin‐dependent scattering centers, as evidenced through the magnetotransport study. In addition, the antiferromagnetic molecule spin chain derives tunable exchange bias, which signifies the dominance of the antiferromagnetic interfacial interaction. Theoretical calculations demonstrate spin configurations of the molecular chain and the antiferromagnetic interfacial coupling through oxygen intermediaries. The development of the molecular multispinterface and controllable exchange bias therein will provide a promising route for the active control of multivalued data processing at the nanoscale.     

C_3分子线在激光场中的含时密度泛函理论研究

运用将含时密度泛函理论(TDDFT)和分子动力学相结合的方法,研究了C3分子线的光吸收谱以及它在强激光场中的电子和离子响应。计算结果表明,C3分子线光吸收谱可以分为两个区域,其中既包含独立的峰,又包含连续分布的峰。对C3分子线在激光场中的研究表明,在激光强度、极化方向及脉冲长度相同的情况下,当激光频率远低于共振频率时,分子的电离发生较晚而且电离较弱,分子沿激光极化方向的偶极矩与激光脉冲波包很相近,分子激发处于线性响应区;当激光频率处于共振频率范围时,C3分子线的电离增强,而且偶极矩的激发与激光脉冲波包完全不同,与分子的电离密切相关。     

带有极性向列相的界面性质——通过分子场理论的分析

通过分子场理论研究了带有极性向列相的界面性质。分子质心固定在简单立方晶格的格点上。分子间存在色散吸引作用和偶极子相互作用。与基板相接触的一层分子受到表面作用。本文作出结论：通常向列相在基板表面作用下可以在界面区中诱导出极性向列序。     

新型喷水室及其应用

喷水室作为一种传统的热温处理空调设备，现在已被应用于微电子行业来去除分子态污染物，并且还可以被应用于直接蒸发冷却技术和热回收系统。介绍了几种新型喷水室及喷嘴，指出喷水室的发展方向。     

Li+附着CH3-nFnO2过氧自由基:络合物Li+-CH3-nFnO2(n=0～3)结构与性质的研究

采用了从头算分子轨道理论（MP2,非限性的二级微扰理论）和密度泛涵理论（B3LYP）,分别在6-31G（d,p）,6-311G（d,p）,6-311＋G（d,p）,6-311G（2d,p）,和6-311＋G（2df,2p）基组上优化CH3-nFnO2-Li^＋（n=0～3）的几何结构,计算出了相关的NBO电荷分布和锂离子相对于自由基CH3-nFnO2的亲和能。并在同一水平上计算了自由基CH3-nFnO2和络合物CH3-nFnO2-Li^＋的相关伸缩振动频率。CH3-nFnO2在UB3LYP／6-311G（d,P）得到的振动频率与实验值符合得很好．根据相关的文献报道,我们运用从头算分子轨道理论和密度泛涵理论计算出的锂离子相对于CH3-nFnO2的亲和能都能够表明络合物CH3-nFnO2-Li^＋在气态下能以一种稳定的物种形态被离子附着质谱检测．     

Promising Perspectives on the Use of Fullerenes as Efficient Containers for Beryllium Atoms

The possibility of using fullerenes as containers for toxic beryllium atoms is studied by a multi-scale approach in which first-principles and classical molecular dynamics simulations are combined. By studying the energetics, electronic and spectroscopic properties of Be-fullerene systems and by simulating their interaction at finite temperature in vacuo and in representative biological environments it is concluded that: i) Be endohedral complexes can be obtained by implanting Be atoms at energies >2.3 eV that is consistent with laser implantation technologies; ii) it is in principle possible to distinguish stable endohedral complexes from metastable exohedral ones by optical absorption, suggesting that optical spectroscopy can be a valuable a non-destructive technique to assist the synthesis and the control of implanted films iii) the Be-endohedral complexes are long-lived and thermodynamically stable and can confine beryllium both in vacuo and in aqueous solution; iv) Be@C60 complexes are likely unable to penetrate the selectivity filters of a prototypical protein showing that fullerene prevents undesired interactions with biomolecules and toxicity effects of Be²⁺ related to replacement of the Ca²⁺. Overall, these results provide an assessment on the possibility to encapsulate Be atoms into fullerenes by ion implantation to synthesize inert and highly stable and safe molecular containers for toxic beryllium radionuclides. Great opportunities are expected for the realization and application of Be-C60 complexes to nanotechnology and nanomedicine with particularly appealing perspectives in the field of neutron capture therapy of cancer.     

场致胆甾相-向列相转变:基于分子场理论的研究

垂直于液晶胆甾相加磁场可以引起胆甾相-向列相转变，基于分子场理论解释了这一现象。在液晶胆甾相，单体取向分布函数按照指向矢的改变定域化。通过对磁场中单分子取向势求平均得到宏观磁场能量；对分子两体作用势作展开，自由能转换为在连续体理论中所具有的形式．得到了发生转变临界磁场的公式。近似计算了温度对临界磁场的影响。     

空间各向异性两体势与液晶定向排列

基于分子场理论，研究一种新的空间各向异性两体作用势。对于该两体势，分子质心固定在简单立方晶格的格点上，而势参数依赖于液晶的弹性常数。通过函数迭代方法解分子取向分布函数满足的自洽方程。在大块液晶内部，存在3组单轴解，它们的指向矢分别沿x，y和z轴方向并且具有相同自由能。通过表面作用势描写摩擦后基板对液晶分子的作用，对20个分子层构成的5CB液晶薄层进行了数值计算。仍存在三种指向矢不同的状态，指向矢沿着摩擦方向的状态具有最低自由能。另外，讨论了表面作用在界面分子层中诱导的双轴序。