变分量子Monte Carlo的一个新算法

提出变分量子MonteCarlo(VMC)计算的新算法-极小化方差(MV)方法.它从局域能的内部结构出发,直接削减其波动以达到将VMC的方差减到极小的目的.给出了局域能的分析表达式,导出VMC的极小方差原理,并建立方差极小化的计算步骤.     

meso-苯基四苯并卟啉锌的合成和光谱性能的研究

四苯并叶琳(TBP)及其金属配合物是一类新型的光敏性分子,其0-0跃迁出现在λ_max大于630nm的红光区,在光功能材料方面显示出良好的应用前景^[1-2].虽然有关meso-四取代四苯并叶琳金属配合物的合成及其光谱性能的研究已有多篇报道^[3-8],但报道方法的产率较低(最高达15%^[7],有关的光谱性能的报道也不一致^[3-5]。     

The method of matrices conjoint multiplication for the problem of circular arc corrugated diaphragm

The circular are corrugated diaphragins are taken in this paper and structures of several sections of the ring shells and a central cireular plale I matrices and link matrices are derived by using Prof. Chuen Hei-zang’s general the ring shell[1] and perturbation theory of the circular thin plates. Throngh the meined of matrices conjoint multiplication, the linear exact solution and nonlinear soluaen are obtained. The resutts agree with that of the experiments presented by W. A. Wildhack..     

时间离散神经振子中的多吸引子共存

本文给出一类耦合时间离散神经网络振子动力学的理论分析和数值模拟结果,重点分析了多吸引子共存的震子及其吸引域的边界（不稳定的周期的周期不变坏）,研究了多上子共趣及耦合强度变化对于神经信号处理保,如受激盛同步和对模式形成有重要影响的锁频现象。     

成都网调工程实施步骤

介绍了成都本地电话网二级交换网路和二级Ｎｏ．７信令网的网调工程实施方案和步骤的确定,以及实践中的体会。     

洛阳市本地电话网网调工程简介

简要介绍了洛阳市本地电话网网调工程的网路调整原则和网调过程,以及网调工程实施后各种业务网的网路组织。     

本地网计费帐务系统的实现

计费帐务系统是本地电话网中最主要的管理系统之一 ,文中从新型计费帐务系统的建设目标出发 ,阐述了本地网内计费信息的在线数据采集 ,实时、准实时计费 ,集中式帐务系统的建设原则、实现方案、软件设计与体系结构。     

Incommensurability in the magnetic excitations of the bilinear-biquadratic spin-1 chain

We study the magnetic excitation spectrum of the spin-1 chain with Hamiltonian .We focus on the range where the spin chain is in the gapped Haldane phase. The excitation spectrum and static structure factor is studied using direct Lanczos diagonalization of small systems and density-matrix renormalization group techniques combined with the single-mode approximation. The magnon dispersion has a minimum at until a critical value is reached at which the curvature (velocity) vanishes. Beyond this point, which is distinct from the VBS point and the Lifshitz point, the minimum lies at an incommensurate value that goes smoothly to when approaches , the Lai-Sutherland point. The mode remains isolated from the other states: there is no evidence of spinon deconfinement before the point .These findings explain recent observation of the behavior of the magnetization curve for . Received 16 December 1998     

Quantum derivation of the excess noise factor in lasers with non-orthogonal eigenmodes

By generalizing recently obtained results we calculate the excess noise factor (Petermann factor) for a laser system with non-orthogonal eigenmodes. The quantum consistency of the calculation is shown through the explicit conservation of input-output commutation rules. As a result of the calculation, the excess noise in the lasing mode is shown to depend on the laser gain below threshold, and on the noise analysis frequency below and above threshold. Received: 27 October 1998 / Received in final form: 11 March 1999     

Ga-NMR study of the low-energy excitations in

We report the results of ⁶⁹Ga- and ⁷¹Ga-NMR measurements on NdGa₂ at temperatures between 0.1 and and in applied magnetic fields between zero and 74 kOe. NdGa₂ orders antiferromagnetically below and undergoes several metamagnetic transitions in external magnetic fields. In zero applied magnetic field and below the temperature dependence of the spin-lattice relaxation rate T1 ^-1 ( T ) shows a large linear-in-T term, about two orders of magnitude higher than for the reference compound LaGa₂. This strong enhancement confirms the presence of low-energy excitations in the antiferromagnetic phase of NdGa₂ as was previously indicated by specific heat data. Above , T1 ^-1 ( T ) is dominated by an exponential term, which we associate with excitations between the lowest energy levels of the f-electron system. The separation of these energy levels is determined by exchange, crystal-field and Zeeman interactions. Received 3 September 1998 and Received in final form 3 November 1998