大枣保花保果复合剂的应用效果

分析了大枣产量低、落花落果严重的原因，介绍了大枣保花、保果复合剂的作用机理及施用方法，并阐述了该复合剂的应用效果和社会经济效益。     

中外低保管理面面观

目前我国城市居民最低生活保障制度的执行情况进展良好。低保政策的执行在保障下岗和失业人员基本生活及促进就业和再就业等方面发挥了明显的作用。但贫困问题是一个世界性问题 ,我们应借鉴各国在缓解贫困方面的作法 ,促进我国城市扶贫工作的顺利进行     

师专化学专业学生化学教育能力评价标准研究

教育评价最核心的部分是建立评价标准，不同的评价标准反映出不同的教育理念，导致不同的评价结果。本文认为，该评价系统以正确的教育思想、启发式的教学方法、民主型的师生关系、良好的教育管理能力和教育效果为评价的标准。     

Analysis of heterojunction resonant cavity-enhanced Schottky photodiodes by using two-valley transport model

The article concerns heterojunction resonant cavity-enhanced (RCE) Schottky photodiodes with GaAs in the absorption layer. The quantum efficiency and linear pulse response have thoroughly been analysed. For the first time, the response of a heterojunction photodiode has been modelled by the phenomenological model for a two-valley semiconductor. The results obtained have shown that the satellite valleys, as well as the parasitic time constant, significantly influence the response and, accordingly, have to be taken into account when analysing and optimizing RCE photodetectors.     

On an approach to the study of the Jaynes–Cummings sum in quantum optics

A new approach to the study of the Jaynes–Cummings sum, which determines the atomic inversion in quantum model of a single two-level atom interacting with a single mode of the quantized radiation field, based on the number theory theorems on approximation of trigonometric sums is presented.      

Nondispersive two-electron wave packets in driven helium

We provide a detailed quantum treatment of the spectral characteristics and of the dynamics of nondispersive two-electron wave packets along the periodically driven, collinear frozen planet configuration of helium. These highly correlated, long-lived wave packets arise as a quantum manifestation of regular islands in a mixed classical phase space, which are induced by nonlinear resonances between the external driving and the unperturbed dynamics of the frozen-planet configuration. Particular emphasis is given to the dependence of the ionization rates of the wave packet states on the driving field parameters and on the quantum mechanical phase space resolution, preceded by a comparison of 1D and 3D life times of the unperturbed frozen planet. Furthermore, we study the effect of a superimposed static electric field component, which, on the grounds of classical considerations, is expected to stabilize the real 3D dynamics against large (and possibly ionizing) deviations from collinearity. Received 7 November 2002 / Received in final form 2 December 2002 Published online 28 January 2003     

Sniffer在Windows 2000下的实现方法

介绍了网络嗅探器（Sniffer）的基本原理，并阐述了Windows2000下Sniffer的基本实现，重点阐述了Windows2000下新的实现方法。     

Classical limit of relativistic quantal system with attractive Coulomb interaction

Using the appropriate harmonic oscillator states and reasonable approximations, we construct coherent wavepackets corresponding to the solutions of the Klein-Gordon equation for the attractive potentialV(r)=−k/r, k>0, in two and three space dimensions. We deduce the corresponding classical limit in two dimension by requiring that the expectation value 〈r〉 of the radial variable is large. In the case of three dimensions, besides the condition of large 〈r〉, we make the uncertainty Δr=[〈r ²〉 − 〈r〉²]^1/2 a minimum with respect to certain parameter of the wavepacket. We then investigate the trajectory traversed by the wavepacket in the classical limit. We find that the classical limit of this relativistic quantal problem gives, in the leading order, the same expression for the rate of motion of the perihelion as that given by the solution of the corresponding special relativistic classical dynamical problem. We also briefly discuss some of the subtle aspects of the classical limit of the relativistic quantal system, in general.     

大众健美操的"应赛"训练

本文试就大众健美操短期集训这种常见的“应赛”现象，探讨教练员在训练前应把握要素和训练中应遵循的原则。     

PB在企业管理系统中与多种数据库的连接

分析了使用面向对象数据库软件Power Builder开发煤气公司一表一卡管理系统过程中，对SQL Server和Visual Foxpro两种不同数据库的连接，提出了解决新系统与旧系统的数据兼容问题。