基于GPRS的GPS实时差分系统研究与实现

介绍了GPS实时差分系统基本原理及实现过程，提出了基于GPRS的GPS实时差分系统的总体结构；完成了基于GR47的GPRS数据传输模块的硬件和软件设计；实现了服务器软件数据监控及处理功能；采用无缝技术实现GPRS与Internet链接，建立了GPS差分数据传输通道；提出了通讯链路时间延迟的测试方法，分析了过大时间延迟的原因并给出了解决方案。实际测试结果表明：基于GPRS的GPS实时差分系统达到了厘米级定位精度。     

两斜交圆柱壳应力分析的边界元法

本文研究了两斜交圆柱壳的边界元法。提出了用板的基本解叠加级数形式的修正项构成圆柱壳的基本解,提高了计算精度,缩短了计算时间。对区域积分进行特殊处理,从而避免了内部网格的划分,大大减少了数据准备工作量和占机内存。并编制了FORTRAN计算程序,进行了数值计算。     

硅微机械陀螺仪的机电接口模型分析

建立了某种硅微机械陀螺仪的电路模型,分析了寄生电容对接口电路的影响.结果表明,合理的接口电路不仅消除了大部分的寄生电容的影响,而且减小了信号的衰减幅度,抑制了大部分的耦合信号和噪声信号.最后对接口电路进行了改进,除了保留以上的一些优点外,还减小了载波信号的变化和电源变化对电容分辨率的影响,提高了整个电路的分辨率.     

钢管桩固结过程的分析

本文用连续介质力学的基本理论分析了钢管桩的固结过程。采用径向固结模型进行了描述并给出了它的解析解。指出了固结过程提高了钢管桩的承载能力。     

激光多光束闸墩位移测量研究

根据实际大型工建筑测试的需要，研究激光多光束的全变位测试方法，提出了相应的计算公式，研究了制造了实用的测试装置，并对大型闸墩进行了实地测量，分析了闸体的损伤程度，作了安全评估。     

超静定梁变形计算的有限差分法

推导了超静定梁变形计算的有限差分方程，研究了边界条件，编制了计算程序，计算 了超静定梁的变形. 文中工作扩大了有限差分法的应用范围.     

绿色润滑油的发展概况

概述了绿色润滑油的发展状况,阐述了绿色润滑油的含义,阐述了绿色润滑油的含义,介绍了生物降解试验方法,通过对绿色润滑油基础油及基适用的添加剂的综述,提出了绿色润滑油发展过程中存在的主要问题,并对将来的发展趋势进行了展望。     

缝合复合材料层板刚度预报

提出了缝合复合材料层板的刚度预报模型,该模型考虑了缝合针脚处的孔洞对刚度的影响,描述了缝合孔洞的几何形态,建立了孔洞形态与纤维弯曲的关系,采用平均刚度法和经典层合板理论进行了刚度预报,获得了与试验数据相吻合的预报结果,表明了该模型的有效性,详细探讨了缝合孔洞对缝合层板刚度的影响规律,得到一些有益结论。     

陀螺马达电源的研究

本文讨论了三相交流陀螺马达电源的工作原理。根据主要技术指标的要求，设计了陀螺马达电源，给出了该电源的各个组成部分的线路设计，解决了研制中出现的电源振荡问题，论述了该电源的设计特点，给出了使用结论     

精细辛算法的高效格式和简化计算

对精细辛几何算法设计了高效的迭代过程，减少了精细积分的计算量，同时提出了精细辛算法的简化形式，避免了复杂的矩阵求逆运算，并给出了相应的误差估计，最后编制了程序进行验证，证明了所采取的方法能够使计算快捷，精度高，稳定性好．     

Mechanical seals with oscillating stator

This paper presents theoretical analyses and experimental investigations of a mechanical seal subjected to axial impulses of one of its mating rings (stator). The amplitude of oscillations of stator depends on the pressure of sealed fluid. The frequency of oscillations is influenced by the geometry of frontal faces of the seal rings and depends on the rotational speed of rotor. The analytical models include the analyses of the static equilibrium of the investigated mechanical seal and the dynamic response of stator. The experimental analysis implies the conception of the testing system, the experimental estimation of the leakage and the measurements of amplitude and frequency of oscillations. During operating time, the experimental variations of leakage of a mechanical seal with oscillating stator are monitored for different rotational speed of rotor. Finite element analysis is used to visualize the stress distribution of stator as a function of the applied forces.     

Solution of the direct problem of the flow of a two-phase mixture of a gas and foreign solid or liquid particles in a laval nozzle

Within the framework of a two-liquid (two-velocity and two-temperature) model of a continuous medium, the article considers the flow of a mixture of a gas and foreign particles in the subsonic, transonic, and supersonic parts of a Laval nozzle. In the case of a thin layer of pure gas near the wall, the problem is solved in two stages. First, the method of establishment is used to calculate the core of the flow, where the gas with the particles is flowing; under these circumstances, the parameters in the layer of pure gas are determined approximately; then simplified equations (of the type of the equations of the boundary layer) are used to find the distribution of the parameters in the zone of pure gas, and the flow in the core of the stream is refined. Examples of the calculation are given. Use of the method developed permitted establishing some of the special characteristics of the flow of a mixture of gas with particles in a Laval nozzle in the case of Stokes flow around the foreign particles.     

Unsteady Liquid Jets

The behaviour of unsteady liquid jets in a gas atmosphere is mainly governed by the conservation of momentum and the interaction with the environment. In this article it will be shown that many of the particular effects in the propagation and desintegration of unsteady jets are simply explained by the conservation of initial momentum. Many of the distortions and peculiar shapes of the liquid elements of the jet can be explained by a time and space development of weak initial distortions of momentum in travelling waves during propagation.The first part of the paper is devoted to the droplet formation in liquid jets of moderate Weber numbers in the order of ten. In this regime and higher the surface tension is not the governing influence of instability of jet decomposition and hence of the droplet formation.If there is a high frequency distortion of the velocity which is artificially implemented in our experiments by a special device, but under usual conditions also existing by turbulence or source distortions of the nozzle flow, the concentration of mass in packets in a kind of shock formation is the main reason for droplet formation. The frequency of droplets in space and time is given by the frequency of the distortion. The amplitude and phase is also given by the initial values of the driver for these quantities.For large amplitudes and low frequencies the jets are decomposed in very peculiar shapes, which can be very simply explained by the collision of packets of concentrated mass on the axis of the jet motion.The whole range of phenomena can be understood in a theoretically elegant manner by a Lagrangian transform of the nonlinear equations of motion together with some plausible considerations about the lateral motion. Solutions for the droplet formation and the formation of liquid films in different shapes can be achieved this way.As an illustration of the whole range of beautiful and regularly reproducible details of jet decomposition some photographs will be shown which summarize the phenomena and give an idea of the importance of systematic investigation of the sometimes very confusing appearance of fluid jets.     

Development of analytical methods in three-dimensional problems of the statics of anisotropic bodies (Review)

The main results of scientific research carried out at the S. P. Timoshenko Institute of Mechanics of the National Academy of Sciences of Ukraine in the field of three-dimensional problems of the statics of anisotropic bodies are stated in a systematic form. The results include the structural method of constructing the exact analytical solutions of equations of the elastic and thermoelastic equilibrium of rectilinearly orthotropic bodies and approximate analytical methods of solving three-dimensional boundary-value problems for curvilinearly orthotropic bodies of canonical and noncanonical form. Results of solution of specific boundary-value problems for orthotropic and transversally isotropic bodies are analyzed. S. P. Timoshenko Institute of Mechanics, National Academy of Sciences of Ukraine, Kiev. Translated from Prikladnaya Mekhanika, Vol. 36, No. 2, pp. 3–38, February, 2000.     

随机-模糊处理方法在岩石力学指标统计及岩组划分中的应用

探讨了随机 模糊处理方法在岩石力学指标统计和岩组定量划分中的应用。文中对计算中的隶属函数取值及迭代方式进行了深入讨论。通过计算结果的比较分析, 认为随机 模糊处理方法更符合实际, 并优于其他方法。最后作者提出了岩组定性划分 岩石样本参数的随机 模糊统计分析 岩组定量划分及参数重新统计的分析程序。     

EFFECT OF STRESS-STRAIN CURVE OF MATERIAL ON SOLUTION OF PLANE-STRESS PROBLEMS WITH LARGE PLSTIC DEFORMATION

本文首先将以前所得到的关于两个轴对称塑性平面应力问题(薄圆环和旋转盘)的有关方程和计算结果作了一个简单的叙述.这些计算结果是根据两种不同硬化特性的材料和一种理想塑性材料的应力应变曲线在不同负荷下计算得到的.这些结果指出这三种不同材料的应力应变曲线和负荷对于这两个问题的主应力比值和比例应变的影响很小,而对于比例应力的影响则很大.之后,分析了二维的塑性平面应力问题的方程;这些方程考虑了大应变,但不包括体积力(body force).分析这些方程中的包括材料应力应变曲线项和载荷数项的结果,认为假若在边界上的主应力的比值和比例应变不变,则材料的应力应变曲线和载荷对于主应力比值和比例应变的分布的影响可能不大,而对于比例应力的影响则很大.这种边界条件在实际问题中的普通加减下,满足的可能想是很大的.薄圆环和旋转盘的边界条件及所得的结果和这分析的结果是完全一致的.从这些结果并可提出一个简单而相当准确的近似解,最后并将本文所得的结果和依留辛(Ильюшии)的理论——关于小应变下三维问题形变理论的应用条件——作了比较.     

Inverse approach and sensitivity analysis for identification of ingot-mould thermal resistance in continuous casting of metals

The problem of appropriate location of the sensors for identification of ingot – mould thermal resistance during continuous casting of metals is the subject of the paper. Analysed problem belongs to the group of inverse problems. The present work shows also the method of identification of unknown thermal resistance using the temperature measurements at the number of sensors located in the wall of the mould. The influence of the location of the sensors on the results of identification is analysed. The best location of the sensors results from the sensitivity analysis for the steady-state inverse heat conduction problem. Validation of the proposed inverse method is realized by comparison of the results taken from solution of inverse and direct problems. Several numerical examples are presented and analysed.     

Boundary layer on the moving surface of a cylinder

A study is made of the problem of the boundary layer on a cylinder with a moving surface when the cylinder moves with constant velocity in an incompressible fluid. Expressions are obtained for the distributions of the frictional stress on the surface of the cylinder and the coordinate of the singular point in the solution of the boundary layer equations that indicates the appearance of a region of reverse flow for different values of the relative velocity of the motion of the surface of the cylinder. Numerical calculations have been made of the work of the force of friction associated with displacement of the cylinder, the work expended on the motion of its surface, and, in the case of flow separation, the work of the pressure forces (it being assumed here that the pressure and friction on the wall behind the singular point are constant and equal to the pressure and friction at the singular point).     

Determination of dynamic sizes during the process of impact of railway wagons

The objective of research in this paper refers to the theoretical and experimental determination of dynamic sizes that occur during the process of impact of railway wagons. At the process of wagons impact as well as at the time of changes of movement regime (starting, stopping, and braking), the longitudinal forces that significantly affect the stress-deformational state of the supporting wagon structure occur. In the process of developing and designing new types of wagons and in the process of identifying the behavior of existing types of wagons, it is necessary to know the values of the most important dynamic sizes that occur during the process of impact. In this paper, a method for determining these sizes is formed by using the theoretical models of impact of wagons. Results of numerical simulation of impact are compared with the results of experimental tests, which were conducted according to international regulations. Research has shown that the results of numerical simulations coincide with the results of experimental tests, with certain exceptions. It is concluded that theoretical model can be used in determining the most important dynamic sizes that occur during the process of wagons impact.