金属氢化物(AlH3)n的热中子非弹性散射谱

本文报道了铝的氢化物(AlH₃)_n在常压和高压50kbar两种情况下的非弹性散射中子能谱,观察到了一些精细结构。与Roszinski的红外吸收谱作比较,在600—1700cm^-1波段内基本一致。而我们还测到了红外方法难以测到的三个低频峰。没有观察到高压对该材料的热学性质和微观结构的影响。 关键词：     

THE SPECTRAL REPRESENTATION OF PROPAGATOR FOR FERMION FIELD AND QUARK CONFINEMENT

The properties of fermion causal Green's function is discussed according to the theory of spectral representation. The definition of effective mass is established from the view point of field theory, and the approximate expression of S_F' (p) as |p²|«M² and the asymptotic formula of S_F' (p) as p²→+∞ is given. In terms of these result the problem of quark confinement is discussed. We find that: (ⅰ) Based on the theory of spectral re presentation the concept of relative confinement is allowed, and if renormalization effect is strong, the quarks can demonstrate definitely lighter effective mass when they are far away from the mass shell; (ⅱ) Based on the theory of spectral representation the concept of absolute confinement is unallowable, even the absolute confinement is taken as the limit of relative confinement. That is if the concept of absolute confinement is introduced, we must discard a part of elementary hypothesis of spectral representation theory.     

THE GAUGE OPERATORS FOR PSEUDOSCALAR FIELDS AND THE BAKER-HAUSDORFF FORMULA

In this paper, we present the explicit expressions of the gauge operators for pseudoscslar fields in a gauge theory coupled vector and axial-vector fields with the aid of the method of operator algebras.The gauge operators of the pure gauge field theory under the chiral group SU(N)×SU(N) are also presented. P9oreover, the explicit expression of the Baker-Hausdorff formula is obtained for a special case and the general situation is discussed.     

Simulation study on cooperation behaviors and crowd dynamics in pedestrian evacuation

Pedestrian evacuation is actually a process of behavioral evolution. Interaction behaviors between pedestrians affect not only the evolution of their cooperation strategy, but also their evacuation paths-scheduling and dynamics features. The existence of interaction behaviors and cooperation evolution is therefore critical for pedestrian evacuation. To address this issue, an extended cellular automaton(CA) evacuation model considering the effects of interaction behaviors and cooperation evolution is proposed here. The influence mechanism of the environment factor and interaction behaviors between neighbors on the decision-making of one pedestrian to path scheduling is focused. Average payoffs interacting with neighbors are used to represent the competitive ability of one pedestrian, aiming to solve the conflicts when more than one pedestrian competes for the same position based on a new method. Influences of interaction behaviors, the panic degree and the conflict cost on the evacuation dynamics and cooperation evolution of pedestrians are discussed. Simulation results of the room evacuation show that the interaction behaviors between pedestrians to a certain extent are beneficial to the evacuation efficiency and the formation of cooperation behaviors as well. The increase of conflict cost prolongs the evacuation time. Panic emotions of pedestrians are bad for cooperation behaviors of the crowd and have complex effects on evacuation time. A new self-organization effect is also presented.     

Nonlinear Dynamical Symmetries of Some Two-Dimensional Quantum Systems

In this paper nonlinear dynamical symmetries of three quantum systems are studied in detail, such as the Kepler-Coulomb system and the isotropic harmonic oscillator in a two-dimensional curved space, and the generalized pseudo-oscillators in the two-dimensional fiat space. Their nonlinear spectrum generating algebras are shown to be relevant to polynomial angular momentum algebras.     

高温电视摄像镜头设计

讨论了在高温环境下使用的电视摄像镜头的设计方法,分析了在这种特殊使用条件下的材料选择、光学参数的确定和光轴的指向问题.提出了一种采用三次成像的方法来实现设计要求,在保持系统各单元孔径都很小的前提下,拉长系统的结构长度,并给出了具体设计结果的评价参数,表明该系统可在较宽的温度范围内获得非常好的成像质量,设计思想适合于高温环境下光学系统的设计实践.     

Casimir-Polder力对左手材料板附近的原子的动力学作用

本文研究了初始处于激发态的两能级原子在左手材料附近运动时Casimir-Polder力对原子动力学的影响. 左手材料有两个的作用: 一是在距离界面波长区域内提供了较强的Casimir-Polder共振力, 二是在这一范围原子的自发辐射受到抑制, 延长了作用时间. 这两种效应使得依靠原子自发辐射这一过程中的Casimir-Polder力能对原子的运动学产生影响, 并将一定初速度的原子排斥远离界面. 由于原子偶极矩的取向会影响Casimir-Polder力的性质, 因此对于某些初始条件(初速度和初始位置), 不同偶极矩取向的原子有不同的运动学结果, 会被吸引到界面或反射出去, 从而对具有不同偶极矩方向的原子进行筛选. 当然由于Casimir-Polder力很小, 能够反射的初速度也很小, 但是已经可以反抗极低温的热涨落, 我们的理论预估值约为15 μupK. 如果和其他约束手段同时作用, 便能对原子的动力学产生更为有利的控制.     

Indecomposable Representations of the Square—Root Lie Algebras of Vector Type and Their Boson Realizations

The explicit expressions for indecomposable representations of nine square-root Lie algebras of vector type, R_νλ (ν, λ=0, ±1), are obtained on the space of universal enveloping algebra of two-state Heisenberg-Weyl algebra, the invariant subspaces and the quotient spaces. From Fock representations corresponding to these indecomposable representations, the inhomogeneous boson realizations of R_νλ are given. The expectation values of R_νλ in the angular momentum coherent states are calculated as well as the corresponding classical limits.     

q变形三参数公式对偶偶核基带的描述

利用q变形三参数公式,计算了锕系和稀土偶偶核基带转动谱,详细分析了拟合参数值呈现出的规律性.结果表明,q变形转动惯量转子模型能够较精确地描述偶偶核基带转动谱.     

显微动态图像分析技术及其在生物物理中的应用

介绍了一种可实时监测细胞生命活动的显微动态图像分析技术。该技术把显微光学成像技术、数字处理技术和动态图像分析技术结合为一体,可实现对活细胞的结构功能、生长过程和环境变化的影响等进行非侵入性连续监测。通过在细胞膜弹性模量测量中的应用表明,该技术不仅原理可靠,实现容易,应用方便,而且检测速度快,测量精度高,稳定性能好。此项技术可望在生物物理学的实验研究中获得广泛的应用。