近期液晶研究中的几个新方向——液晶非显示应用基础研究的进展

近期有关液晶学科的更多的基础和应用基础研究转向了应用这个奇妙的软物质态于平面显示器件等光学领域以外的其它领域的深入探索,这就形成了近期液晶科学研究中的‘非显示’热,它囊括了从生物,化学到物理,材料甚至工程等多个学科的诸多领域。本综述主要在物理及相关领域内简略地介绍了几个液晶科学非显示研究课题的基本原理,进展和可能的前景,包括作者所在课题组近期所进行的有关微波频率和中远红外(THz)波段液晶调制器的研究进展。以期为工作于液晶学科这方面研究的同行提供一点参考。     

∧c^＊ in a coupled-channel baryon-meson scattering

Possible structures and properties of some excited states of Λ_c⁺ dynamically generated in the coupled-channel P-wave meson-baryon scattering are studied by solving the Bethe-Salpeter(BS) equation in the framework of the Chiral Unitary Approach. It is shown that both Λ_c⁺(2765) and Λ_c⁺(2940) could be generated dynamically and could be compound states with multi-configuration molecular-like structures. The couplings of the generated states to various reaction channels are also calculated. Moreover, two highly excited states, Λ_c⁺(3024) and Λ_c⁺(3134), are predicted.     

Mott-Hubbard transition of bosons in optical lattices with two-body interactions

In this paper, based on the Bose-Hubbard model with two-body on-site interactions, we study the quantum phase transition between the superfluid state and the Mott-insulator state. With the decoupling approximation, we get the relation between the weak superfluidity and dimensionless chemical potential with different particle number and different dimensionless interaction strength, and the relation between the weak superfluidity and the reciprocal of dimensionless interaction strength with different particle number. We also calculate the corresponding experimental parameters.     

基于线性霍尔传感器的太阳能磁悬浮演示仪

应用电磁学理论、机械力学以及电子技术自制了一套太阳能磁悬浮演示仪,该演示实验仪由太阳能电池供电,利用线性霍尔传感器来探测悬浮物体的位移,以达到控制悬浮的目的,添加数码管电压显示电路,可以定量显示电磁铁的磁性在悬浮过程中随悬浮物位置变化的自动调整,能精确而直观地演示磁悬浮的物理现象该仪器结构简单、性能稳定、操作方便,能广...     

Geometric Property （T）

This paper discusses“geometric property （T）”. This is a property of metric spaces introduced in earlier works of the authors for its applications to K-theory. Geometric property （T） is a strong form of “expansion property”, in particular, for a sequence （Xn） of bounded degree finite graphs, it is strictly stronger than （Xn） being an expander in the sense that the Cheeger constants h（Xn） are bounded below. In this paper, the authors show that geometric property （T） is a coarse invariant, i.e., it depends only on the large-scale geometry of a metric space X. The authors also discuss how geometric property （T） interacts with amenability, property （T） for groups, and coarse geometric notions of a-T-menability. In particular, it is shown that property （T） for a residually finite group is characterised by geometric property （T） for its finite quotients.     

非对称需求扰动信息下的供应链显示机制设计

研究由一个供应商和一个零售商组成的供应链在非对称的需求扰动信息下的显示机制设计问题。假定市场需求为指数函数形式和常数柔性需求函数形式,给出了非对称的需求扰动信息下的供应链最优契约,并且分析了非对称扰动信息对于供应链性能的影响。研究表明,当市场需求为指数函数形式和常数柔性函数形式时,仍然可以设计有效的契约菜单来改善供应链的运作性能;当需求扰动满足一定条件时,初始的生产计划仍然是最优的;非对称需求扰动信息并不必然会给供应链带来利润损失,并且显式地给出了非对称的需求扰动信息不会给供应链带来利润损失的条件。