Acyclic cucurbiturils and their applications

Journal of Inclusion Phenomena and Macrocyclic Chemistry - Acyclic cucurbit[n]urils are a novel type of cucurbituril derivatives, consisting of a central glycoluril tetramer skeleton, two...     

低温固相反应法制备钠快离子导体NaZr2(PO4)3粉体

为了进一步促进钠快离子导体磷酸锆钠(NaZr2(PO4)3)粉体的实际应用,本文提出了一种以氧氯化锆(ZrOCl2·8H2O)和二水磷酸二氢钠(NaH2PO4·2H2O)为原料的低温固相反应法制备NaZr2(PO4)3粉体.通过XRD,SEM和Raman等测试手段系统研究了磷酸盐用量对制备磷酸锆钠粉体的影响.结果 表明:采用超量的磷酸盐有利于纯相磷酸锆钠粉体的合成.同时当锆盐与磷酸盐的摩尔比为2∶5.4时,能够合成平均粒径1μm,尺寸均匀,分散性良好的磷酸锆钠粉体.研究发现研磨时发生的固相反应对磷酸锆钠粉体的制备有重要作用,一方面促进了无定型磷酸锆钠的产生,有利于磷酸锆钠晶体形成;另一方面原位生成的氯化钠为晶体的生长提供了良好的液相环境,促进了磷酸锆钠粉体的低温合成.该工作为磷酸锆钠粉体的大规模生产提供了一条简单有效的方法.     

The Derivative Nonlinear Schrödinger Equation with Zero/Nonzero Boundary Conditions: Inverse Scattering Transforms and N-Double-Pole Solutions

In this paper, we report a rigorous theory of the inverse scattering transforms (ISTs) for the derivative nonlinear Schrödinger (DNLS) equation with both zero boundary conditions (ZBCs) and nonzero boundary conditions (NZBCs) at infinity and double zeros of analytical scattering coefficients. The scattering theories for both ZBCs and NZBCs are addressed. The direct scattering problem establishes the analyticity, symmetries, and asymptotic behaviors of the Jost solutions and scattering matrix, and properties of discrete spectra. The inverse scattering problems are formulated and solved with the aid of the matrix Riemann–Hilbert problems, and the reconstruction formulae, trace formulae and theta conditions are also posed. In particular, the IST with NZBCs at infinity is proposed by a suitable uniformization variable, which allows the scattering problem to be solved on a standard complex plane instead of a two-sheeted Riemann surface. The reflectionless potentials with double poles for the ZBCs and NZBCs are both carried out explicitly by means of determinants. Some representative semi-rational bright–bright soliton, dark–bright soliton, and breather–breather solutions are examined in detail. These results and idea can also be extended to other types of DNLS equations such as the Chen–Lee–Liu-type DNLS equation, Gerdjikov–Ivanov-type DNLS equation, and Kundu-type DNLS equation and will be useful to further explore and apply the related nonlinear wave phenomena.

     

双甘氨肽与高定向热解石墨的散射动力学研究

本文通过反应力场来研究中性双甘氨肽与高取向热解石墨的碰撞动力学过程，分别模拟初始入射角度为0o、20o、45o和70o以及入射能量为481.5 kJ/mol和表面温度为677 K的情况，并且确定和分析了散射产物的角度分布、平动能分布、内能分布和表面滞留时间分布. 双甘氨肽是一种多原子分子，具有较多的低频振动模式和较强的表面吸附相互作用，这些使得碰撞过程的表面滞留时间较长和容易造成能量损失，尤其是表面法线方向. 由于碰撞分子的动量沿表面法线方向上明显地发生损失，而沿表面平行方向上的动量则会大部分保留，因此，其散射角通常会呈现出超镜面反射分布，并且末态的平动能要远小于所谓硬立方模型的预测值. 本文加深了多肽分子与高取向热解石墨碰撞及其能量转移过程的认识和理解，有助于设计在稀薄大气中收集这类大分子的中性气体浓缩器.     

Bioinspired Healable Mechanochromic Function from Fluorescent Polyurethane Composite Film

Camouflage and wound healing are two vital functions for cephalopods to survive from dangerous ocean risks. Inspired by these dual functions, herein, we report a new type of healable mechanochromic (HMC) material. The bifunctional HMC material consists of two tightly bonded layers. One layer is composed of polyvinyl alcohol (PVA) and titanium dioxide (TiO₂) for shielding. Another layer contains supramolecular hydrogen bonding polymers and fluorochromes for healing. The as-synthesized HMC material exhibits a tunable and reversible mechanochromic function due to the strain-induced surface structure of composite film. The mechanochromic function can be further restored after damage because of the incorporated healable polyurethane. The healing efficiency of the damaged HMC materials can even reach 98 % at 60 °C for 6 h. The bioinspired HMC material is expected to have potential applications in the information encryption and flexible displays.     

Dynamics of strong-field double ionization of H_2 in co-rotating two-color circularly polarized laser fields

Double ionization of H_2 in a co-rotating two-color circularly polarized(TCCP) laser field is theoretically investigated. By changing the ratio of electric field peak amplitudes of the TCCP laser pulses, the double ionization probability as a function of the laser intensity shows a clear knee structure, which is suppressed significantly in the case of the atom. Due to the large spatial range of the electronic initial distribution, with the analysis of classical trajectories of ionized electrons, it is found that the ionization of the electron in the farther distance increases the probability of recollision. Furthermore, the yield of nonsequential double ionization created by the recollision can be enhanced by controlling the amplitude ratio of the TCCP laser field.     

Entropy of higher-dimensional charged Gauss–Bonnet black hole in de Sitter space

The fundamental equation of the thermodynamic system gives the relation between the internal energy, entropy and volume of two adjacent equilibrium states. Taking a higher-dimensional charged Gauss–Bonnet black hole in de Sitter space as a thermodynamic system, the state parameters have to meet the fundamental equation of thermodynamics. We introduce the effective thermodynamic quantities to describe the black hole in de Sitter space. Considering that in the lukewarm case the temperature of the black hole horizon is equal to that of the cosmological horizon, we conjecture that the effective temperature has the same value. In this way, we can obtain the entropy formula of spacetime by solving the differential equation. We find that the total entropy contains an extra term besides the sum of the entropies of the two horizons. The corrected term of the entropy is a function of the ratio of the black hole horizon radius to the cosmological horizon radius, and is independent of the charge of the spacetime.     

基于能力培养的应用型本科物理实验教学模式探索

通过对传统大学物理实验教学现状的分析和讨论,针对目前大学物理实验课程的教学模式进行研究,在遵循实验教学自身规律的前提下,构建“模块化”实验课程教学模式,从而改善课程结构,为培养学生解决具体问题的实践能力和创新思维提供针对性的训练;并采用“启发式”“问题式”的教学方法和多样化的考核评价标准,对于不同专业、不同基础、不同背景的学生进行差异化教学,建立以人才培养为核心的科学教学体系,进一步提高大学物理实验课程的教学质量和效果.     

塞曼效应仿真实验平台

塞曼效应实验是学生了解原子具有磁矩和空间取向量子化现象的重要实验,至今塞曼效应仍是研究能级结构的重要方法之一.为了能够让学生更加清楚地了解塞曼效应实验的基本原理和操作规程,针对教学中的重点和难点,运用flash软件制作出塞曼效应仿真实验.该程序可全程高度仿真实验过程,具有界面友好、易于操作、无需安装等优点.为实验教学提供了一种新的辅助方式.