Atomic-scale simulations for lithium dendrite growth driven by strain gradient

Dendrite formation is a major obstacle, e.g., capacity loss and short circuit, to the next-generation high-energy-density lithium (Li)-metal batteries. The development of successful Li dendrite mitigation strategies is impeded by an insufficient understanding in Li dendrite growth mechanisms. The Li-plating-induced internal stress in Li-metal and its effects on dendrite growth have been widely studied, but the underlying microcosmic mechanism is elusive. In the present study, the role of the plating-induced stress in dendrite formation is analyzed through first-principles calculations and ab initio molecular dynamic (AIMD) simulations. It is shown that the deposited Li forms a stable atomic nanofilm structure on the copper (Cu) substrate, and the adsorption energy of Li atoms increases from the Li-Cu interface to the deposited Li surface, leading to more aggregated Li atoms at the interface. Compared with the pristine Li-metal, the deposited Li in the early stage becomes compacted and suffers the in-plane compressive stress. Interestingly, there is a giant strain gradient distribution from the Li-Cu interface to the deposited Li surface, making the deposited atoms adjacent to the Cu surface tend to press upwards with perturbation and causing the dendrite growth. This provides an insight into the atomicscale origin of Li dendrite growth, and may be useful for suppressing the Li dendrite in Li-metal-based rechargeable batteries.     

A New Type of Terahertz Waveguides

A new type of THz waveguides, which employs a solid polyethylene rod as the core and polyethylene tubes in a periodic array of square lattice as the cladding, is proposed. Optical properties of this new THz waveguide, especially in dispersion, confinement loss and single mode property, are investigated in detail with the plane wave expansion method and the beam propagation method. Numerical results demonstrate that the new THz waveguide can reach not only low dispersion but also low confinement loss at single mode propagation. Therefore, the square lattice structure is a better candidate as THz waveguides than the triangular ones.     

仓库容量有限条件下的随机存贮管理问题的评注

给出2005年全国部分高校研究生数学建模竞赛D题的研究背景,对参赛论文作了简要评注,并提供了一种参考解答.     

电感耦合等离子体原子发射光谱法测定中药方剂煎煮液中的微量元素

本文采用HNO3－H2O2对中药方剂煎煮液进行处理，拟定了电感耦合等离子体原子发射光谱法同时测定试样中12个微量元素的方法，选择了仪器的最佳工作条件，考察了基本效应的影响。在选定条件下，12个微量元素的检出限为0．10－5．0ng/g，相对标准偏差为0.10%-9.5%(n=10),加标回收率为85％－103％。该方法简单、快速，已用于大量样品的检测，分析结果满意。     

高温水蓄冷空调的原理和理论分析

介绍了一种新型高温水蓄冷空调方案的原理井进行了理论分析。它可利用高至３８℃水的显热或其它材料的相变潜热来蓄冷空调．分析了完全不掺混系统的性能与过冷水流率的关系；给出了完全掺混系统非稳态循环的性能变化；数值计算并讨论了蓄冷水部分掺混系统的温度分层和动态特性、为高温水蓄冷空调系统的设计和运行提供了理论指导．     

Ⅴ型三能级原子与双模奇偶纠缠相干光场相互作用系统的光子统计性质

本文采用求解Schroedinger方程和数值计算方法，研究了Ⅴ-型三能级原子与双模奇偶纠缠相干光场相互作用系统的光子统计性质，结果表明：此性质与双模奇偶纠缠相干光场的纠缠程度、失谐量、原子的初态以及双模光的平均光子数相关联．     

环保意识调查问卷的Logistic模型

本文应用多元统计分析中的方差分析 ,logistic模型等方法对环保意识调查问卷反馈的信息进行统计分析 ,建立被调查企业对环境保护意识的logistic模型 ,进而可对企业家的环境保护意识的好坏进行判断。     

Assisted Cloning and Orthogonal Complementing of an Arbitrary Unknown Two-Qubit Entangled State

Based on A.K. Pati‘s original idea [Phys. Rev. A 61 (2000) 022308] on single-qubit-state-assisted clone, very recently Zhan has proposed two assisted quantum cloning protocols of a special class of unknown two-qubit entangled states [Phys. Lett. A 336 (2005) 317]. In this paper we further generalize Zhan‘s protocols such that an arbitrary unknown two-qubit entangled state can be treated.     

醇+N-甲基哌嗪二元体系的体积性质

采用振荡管式数字密度计分别测定甲醇、乙醇、正丙醇、异丙醇、丁正醇和异丁醇与N-甲基哌嗪组成的二元体系在298.15K下的密度，计算了超额摩尔体积、超额偏摩尔体积、表观摩尔体积、偏摩尔体积等体积性质，从分子相互作用角度讨论了这些二元体系的体积性质的变化规律，为N-甲基哌嗪的开发和研究提供基础数据和信息。     

流体静高压下的锂离子导电性

本文改进实验方法,在0.0001—1.23GPa流体静高压下测量了整片非晶锂离子导体B₂O₃-0.7Li₂O-0.7LiCl-xAl₂O₃(x=0.05;0.15)及其粉末压片的离子电导率及激活体积。发现粉末压片电导率峰值是由非晶微粒间的接触电导及非晶微粒体电导两者叠加;对整片非晶电导率的压力效应用离子迁移通道的物理图象给出初步的微观解释。此外,还观测到氧化铝组分减少使电导率的压力转变点明显降低;测量出不同温度热处理以及300℃等温热处理4—20h后离子电导率-压力曲线的变化规律,仍可归因于非晶态相分离及两种非晶相的先后晶化。 关键词：