Visual FoxPro数据库文件的结构分析与实用方法

文章通过对FOXPRO6.0版本的DBF和FPT文件的内部存储结构的分析,分别讨论了修复失去FPT文件的数据库和对重要数据库文件进行加密的方法.并给出了FOXPRO6.0环境下的实用程序.     

活载作用下简支梁桥的内力计算

桥梁活载内力计算因活载种类多及作用的不确定性而复杂,本文就简支梁桥分别在汽车荷载及人群荷载作用下的内力计算进行了阐述。     

中小企业的内部控制制度的建立

内部控制制度是制约中小企业发展的瓶颈。内部控制制度存在缺陷,企业的效率就不高,企业的财务就容易出现混乱。因此,如何建立中小企业内部控制制度,就成了保证中小企业健康发展的重要条件。而建立中小企业的内部控制制度则可以从内部控制的实现方式入手,依据内部控制的实现方式建立中小企业内部控制制度。     

生态力概念

生态力指生物与环境之间物流、能流和信息流的驱动力。生态内力是生物的生理代谢活动能力，它把从环境中吸入的物、能转化为生物本体的物、能，并将部分内在的物、能输出体外，显示了生物本身的活力和生产力；生态外力则是环境综合作用向生物输送物、能的力量。生态内力与生态外力之和称为生态合力，它是生态动态平衡的指标，表示环境条件的适宜程度。生态力的研究尚属起步，其概念、理论和方法有待进一步发展和完善。     

Disturbance Attenuation State-Feedback Control for Uncertain Interconnected Systems

This paper studies the problem of robust H∞ control design for a class of uncertain interconnected systems via state feedback. This class of systems are described by a state space model, which contains unknown nonlinear interaction and time-varying norm-bounded parametric uncertainties in state equation. Using the Riccati-equation-based approach we design state feedback control laws, which guarantee the decentralized stability with disturbance attenuation for the interconnected uncertain systems. A simple example of an interconnected uncertain linear system is presented to illustrate the results.     

应用激光全息术研究轴针式喷嘴燃油喷雾特性

本文应用调Q红宝石激光全息照相技术,对轴针喷嘴的燃油喷雾特性进行了研究,证实了喷雾初始段内部存在一个空心的内区,并在广安博之的孔式喷雾分裂长度公式的基础上,提出了应用于轴针喷嘴喷雾的准分裂长度半经验公式,同时还对粒径的空间分布特性进行了测定分析.     

铌酸锂单晶的内旋转和电子态

将铌酸锂单晶在各种温度下出现的结构参数和物性参数异常现象同氧八面体内旋转理论进行了对比,单纯从晶格动力学角度不足以解释实验现象.用正电子湮灭寿命谱技术在20—85℃范围对晶体中的电子态探测的结果表明,存在着自由态和捕获态两种湮灭机构.捕获态的长寿命和相对成份在75℃附近出现异常,可以解释为价电子态在转变过程中的弛豫效应.     

Background current affects the internal wave structure of the northern South China Sea

The internal wave modal equations are solved with the consideration of background currents. Analytical and numerical solutions of some specific examples, including observations in the northern South China Sea （SCS）, are obtained to investigate the effect of back- ground current on internal wave vertical structure. The effects of current shear and curvature on internal wave vertical structure are eval- uated separately. It is found that the phase speed and wave structure are modified by background currents, the current shear has little effect on wave structure, whilst the current curvature could have a strong impact on the wave structure. The extent of the effect by the current curvature on the wave structure depends on the magnitudes of current curvature, relative wave speed, and buoyancy frequency, sometimes the effect by the current curvature may even cause the wave to attenuate severely with depth. A new method to obtain the real eigenfunction with depth in the case that the waves become evanescent is also put forward. It is shown that the residual tidal current in the northern SCS is strong enough to cause the wave to attenuate severely at the uooer laver.     

治疗创伤性上颈椎不稳13例临床分析

目的回顾创伤性上颈椎不稳病例13例,强调早期诊治的重要性及治疗原则.方法对未合并横韧带断裂病例采用保守治疗,合并横韧带断裂者应早期外科干预.结果保守治疗3~5个月可恢复,手术治疗可完全恢复.结论全面查体及影像学检查早期可确诊,Aprofix内固定系统具有固定可靠,操作简单,且该内固定系统具有良好的生物学相容性及生物力学性能,是治疗创伤性上颈椎不稳的较好的内固定方法之一.