THE CANONICAL TRANSFORMATION AND THE SPIN WAVE IN TWO DIMENSIONAL HEISENBERG ANTIFER-ROMAGNETIC SYSTEM

The canonical transformation in two dimensional Heisenberg antiferromagnetic system is given in this paper.It is found that under this transformation the 2D Heisenberg antiferromagnetic model is the nonlinear O(3) σ model with a topological term in the continnum limit.Since there exists a large uncertainty when one chooses the canonical variables,it is not completely concluded that whether the topological term really occurs in this system.Finally,the physical meaning of the canonical transformation is also investigated,and it is found that it corresponds to the collective excitations of system spins,i.e.,a kind of spin waves exists in this case.     

黑洞能量涨落和黑洞视界邻近的辐射气温度上限

本文应用弯曲时空正则量子化方法,在1+1维情况下,证明了辐射气的温度分布函数为T(r)(gtt)^1/2=常数。进而讨论了1+1维Schwarzschild黑洞情况下黑洞能量的涨落现象,并由此估计了辐射场温度的上限。 关键词：     

用统计力学方法讨论平衡稳定条件

一.引言 1876年吉布斯(J.W.Gibbs)首先论述了物体系的平衡稳定条件,普朗克(M.Planck)也曾用孤立系熵增加原理讨论了单元系与二元系的稳定条件,1948年王竹溪先生用吉布斯的能量最小判据法系统地全面地研究了物体系的平衡稳定条件问题,其结果为对于任一具有l种分子的均匀系统,平衡稳定条件为l 1个独立的不等式:     

一种Lorentz引力规范理论的正则形式

本文选择了一个特殊的、在任意座标变换下及局部Lorentz变换下不变的Lagrangian,着重讨论了在经典意义下的运动方程、给出了与Lagrangian相应的正则形式。 关键词：     

转动相对论系统动力学的积分理论

建立转动相对论系统动力学方程的积分理论.给出系统运动的第一积分,分别利用系统的循环积分和能量积分降阶运动方程,得到推广的Routh方程和推广的Whittaker方程,建立系统运动的正则方程和变分方程,并由第一积分构造系统的积分不变量.给出系统的Poincaré-Cartan型积分变量关系和积分不变量. 关键词： 转动相对论 运动方程 积分方法     

表面沸腾中接触角对液体过热度的影响

表面沸腾中接触角对液体过热度的影响刘朝，曾丹苓（重庆大学热力工程系重庆６３００４４）关键词液体过热度；接触角；涨落；统计系综１引言液体极限过热度的研究是研究沸腾热物理过程的基础。更为重要的是，液体的过热现象直接涉及到许多工程问题和技术安全问题。在实际...     

无穷排斥作用一维费密气体的热力学

采用巨正则系综理论,对以推斥两体δ函数势作用着的一维非理想费密气体,在极端强耦合情况下的热力学性质进行了讨论,并得出这种模型存在“剩余”熵;最后把结果推广到任意自旋情形。 关键词：     

巨正则量子Monte Carlo方法和二维Hubbard模型的研究

用巨正则量子Monte Carlo方法,计算了二维单带Hubbard模型的局域磁矩、磁化率、交错磁化率和内能等物理量.结果表明,用巨正则量子Monte Carlo方法能够统一地研究Hubbard模型的关联强度从弱至强区域的性质,它是处理强关联多体系统的有效方法.     

ON THE BEHAVIOR OF PHASE TRANSITION SHOWN IN DISASSYMBLY PROCESSES OF VERY HOT AND DILUTE FINITE NUCLEAR SYSTEMS

The behaviors of phase transition shown in disassymbly processes of very hot and dilute finite nuclear system have been exposed by using canonical (microcanonical) ensemble Monte Carlo simulation.It is explained that they result from the competition between Coulomb interaction and the effect of finiteness.     

炔氢和炔碳化学位移的本质

系统分析了脂肪族、脂环族、共轭和芳香的以及杂环炔类化合物中的炔键对相连质子和碳原子以及炔碳和相关自旋核的化学位移的影响,结果表明,目前化学位移理论中所采用的炔键在磁场中产生垂直于键轴的环流模型与实验结果有严重矛盾.采用三键的去屏蔽作用、SP杂化和核周电子云变形模型则可对实验事实得到较合理的说明.     

The Canonical Path Integral Quantization of CP1 Model

The Hamilton-Jacobi method of quantizing singular systems is discussed. The equations of motion are obtained as total differential equations in many variables. It is shown that if the system is integrable, then one can obtain the canonical phase space coordinates and the set of the canonical Hamilton-Jacobi partial differential equations without any need to introduce unphysical auxiliary fields. As an example we quantize the CP¹ model using the canonical path integral quantization formalism to obtain the path integral as an integration over the canonical phase-space coordinates.     

利用正则变换推导能量—时间不确定关系

利用Ｋｏｂｅ引入的正则变换以及Ｄｉｒａｃ的正则量子化程序，给出了推导能量－时间不确定关系的一种新方法。     

梯形自旋链的一种规范场论的形式

考虑无质量费米场和规范场的Pauli相互作用项的系统,在这一理论中耦合常数为无量纲量.该模型等价于自旋1/2反铁磁XXZ量子链.如在模型中引入费米场的味自由度,则可定性描述二条自旋链的梯形结构系统.在这一系统中不再存在无能隙激发. 关键词： 梯形结构 规范场 自旋链     

约束系统正则形式的对称性质

本文导出场论中用奇异拉氏量描述的系统正则形式的广义Noether第一定理(GNFT),导出无限连续群下变更性系统正则形式的广义Noether恒等式(GNI),讨论了它们在Dirac约束理论中的应用。给出一个新的反倒,说明Dirac猜想失效,指出某些变更性系统也具有Dirac约束,讨论了GNI在色动力学中的应用。 关键词：     

ON THE TWO DIMENSIONAL NON-LINEAR σ MODEL WITH WESS-ZUMINO TERM II QUANTUM THEORY

The canonical quantization is carried out for the two dimensional non-Linear a model with wess-2umino term. It is shown that the currents in this model satisfy a Kac-Moody algebra for arbitrary values of the coupling constant.     

利用强迫振动扭摆方法测量液体粘滞系数的原理

研究了利用强迫振动扭摆方法测量液体粘滞系数的原理-由标准滞弹性体的Voigt型三参数模型确定了测量系统的基本参量,从而证明了利用强迫振动扭摆测量液体粘滞系数的四参数模型的正确性- 关键词：     

SURFACE QUALITY OF A WORK MATERIAL'S INFLUENCE ON THE VIBRATIONS OF THE CUTTING PROCESS

The problem of stability in the machining processes is very important and is strictly connected with the final quality of the product. In this paper, the vibrations of a tool-workpiece system induced by random disturbances in a straight turning process, and their effect on a product surface is considered. Based on experimentally obtained system parameters simulations are provided using a one-degree-of-freedom model. Noise has been introduced into the model by the Langevin equation. The product surface shape and its dependence on the level of noise has also been analyzed.     

小型低值LD激光测距仪的测距能力与系统的信噪比

研制成一种小型、便携式、低值、对人眼安全、无合作目标的小型低值半导体LD激光测距仪.工作波长λ=905nm;测距范围14～1000m;测距精度<±1m;重复频率100Hz.有多种工作模式,具有省电功能.它的测距能力优于国内外同类低值LD激光测距仪.LF-1激光测距仪是一种光子雷达系统.本文从光子测距方程、系统结构、信噪比分析角度,讨论了系统的测距能力.     

THE QUANTUM CORRECTIONS ON THE THEORY OF TRANSITION RADIATION

A Scheme of quantum treatment for transition radiation is proposed. The Fresnel coefficients are adopted to describe the stationary states of electromagnetic fields near the interface between two mediums before a canonical field quantization procedure can be performed. Then an usual perturbation approach in field theory leads to the general expressions of radiation intensity in two different polarizations. The second order quantum corrections are ascribed to the existence of electron spin. Some concrete formulas for the cases of electron or monopole acrossing a metal surface are presented as well.

     

Quantal Symmetries in the Non-Linear Sigma Model with Maxwell–Chern–Simons Term

The quantal symmetry property in the CP1 non-linear sigma model with Abelian–Maxwell–Chern–Simons (AMCS) term in 2 + 1 dimensions is studied. In the Coulomb gauge, the system is quantized in the Faddeev–Senjanovic (FS) path-integral formalism. The canonical Ward identities for proper vertices under local gauge transformation are derived. Based on the quantal symmetries of a constrained Hamiltonian system, the fractional spin at the quantum level of this system is also presented as those of the system without Maxwell term.