单链DNA在受限环境中伸展的Monte Carlo模拟

Stretching and relaxation of a single DNA molecule tethered in a specially designed thin slit were studied using Monte Carlo simulation combined with bond fluctuation method. It was found that the extension and relaxation of the single DNA molecule are greatly affected by the confined environment. If the extent of the confined environment is increased by decreasing the distance between the two planar surfaces of the slit, the extension of the single DNA molecule increases, due to the screening of the hydrodynamic interaction of DNA segments by the planar surfaces of the slit. The relaxation of the single DNA molecule in different confined environments verifies this assumption completely. The correlation between the end-to-end separation and flow velocity obtained by Monte Carlo simulation is in good agreement with either the experimental results or theoretical consideration reported previously.     

一类化学反应系统在外涨落作用下随机统计性质的研究

本文研究了在外涨落作用下的化学反应系统X(?)Y(?)A,得出了该系统的随机动力学方程的含时解,并研究了该化学反应体系在定态下的宏观统计性质。     

Magnetic Properties of Ferromagnetic Double Layers with Ferrimagnetic Interlayer Coupling at Zero Temperature

Spin-wave theory is used to study magnetic properties of ferromagnetic double layers with a ferrimagnetic interlayer coupling at zero temperature. The spin-wave spectra and four sublattices magnetizations and internal energy are calculated by employing retarded Green function technique. The sublattice magnetizations at ground state are smaller than their classical values, owing to the zero-point quantum fluctuations of the spins.     

Forced Time-Dependent Harmonic Oscillators in Non-Commutative Space

For the time-dependent harmonic oscillator and generalized harmonic oscillator with or without external forces in non-commutative space, wave functions, and geometric phases are derived using the Lewis-Riesenfeld invariant. Coherent states are obtained as the ground state of the forced system. Quantum fluctuations are calculated too. It is seen that geometric phases and quantum fluctuations are greatly affected by the non-commutativity of the space.     

κ-卡拉胶热可逆凝胶的非遍历行为研究

采用散射斑纹(speckle)技术, 即散射光强涨落法, 研究了κ-卡拉胶(KC)热可逆凝胶的非遍历行为. 证明了非遍历性的存在, 并研究了浓度、温度等条件对该非遍历性的影响. 结果表明：该物理凝胶存在非遍历性, 并随KC浓度增加, 凝胶非遍历性增大；随温度升高, 凝胶非遍历性逐渐减小, 直至消失.     

现代高分子物理课程系列漫谈:I.金兹堡判据

金兹堡判据是判定平均场理论有效性的重要准则.本文从一道典型的高分子物理课程课后习题出发,通过求解过程总结在平均场理论框架下如何构造金兹堡判据,并将该思路推广到不对称两组分高分子共混物体系以及高分子溶液体系.     

对流扩散传质滞后的电极过程中之非Poisson涨落与非Nernst浓度极化

根据对流扩散传质滞后的恒稳电极过程中边界层的物理图像, 提出了该类电极过程的简化随机模型, 建立了相应的浓度极化的随机热力学理论, 揭示了非Nernst浓度极化来自于随电流密度增大电极化学反应体系涨落分布的非Poisson化与对中心极限律的偏离, 进一步阐明了与滞后的扩散步骤共存的对流传质对非Nernst浓度极化的效应及其规律. 同时, 给出了对流引起的非Nernst浓度极化的随机热力学算例.     

高分子链坍塌转变动力学过程的动态蒙特卡罗模拟

基于键长涨落格子模型和动态蒙特卡罗模拟方法,引入疏水相互作用,对均聚高分子链坍塌转变动力学过程进行了模拟研究.模拟发现,其坍塌时间呈高斯分布,而平均坍塌时间随淬火深度的变化类似于蛋白质折叠,但难以发现局部最小;另外,平均坍塌时间随链长呈指数形式变化.在其坍塌动力学过程中,高分子链构象先由橄榄球状演变为项链状,进而演变为香肠状,最后形成近球状的熔融球;基于团簇数目、团簇大小和非球面参数等参量,对前人提出的动力学过程四阶段划分进行了更为清晰的界定.     

铁磁体中磁振子的压缩态

研究了铁磁体中磁振子的压缩态．采用霍尔斯坦和普里马科夫提出的二次量子化方法把磁振子系统的．哈密顿量简化,并应用平均场理论处理了哈密顿量中的非线性相互作用项;通过计算自旋涨落的平均值得到了产生压缩态的周期性条件;测得压缩态的周期,可得到铁磁材料的一些重要的物理量的信息,如交互积分等．实验表明,利用铁磁共振扩散实验可以检测磁振子的压缩态。压缩程度越大,共振吸收系数（RAC）越小．实验还表明,磁振子压缩态的量子涨落小于相干态时的量子涨落,这也提高了对可观测量的测量精度．