单元

It is proved that the method using the BEM to calculate the load distributions on the contact lines of involute gear pair, in which the applied load is taken in the form of a concentrated one at a single node, is not suitable. A method in which the tractions of the BEM are made to imitate the Hertzian pressure of the gear using 8 nodes isoparametric elements is introduced.

本文解决了边界元法在空间啮合副计算中存在的系数矩阵的存储，奇异单元积分的计算、表面不连续点处面力一点多值和求解未知量的线性方程组矩阵元素的计算等问题，编制了比不采用上述处理方法的一般边界单元法节省近一半内存和计算时间的适合空间啮合副的三维边界元法计算程序。

The isotactic polypropylene obtained with Et3 Al contained ethylene units when the ratio of Al to Ti was 150 at 100℃.However,the isotaetie polypropylenes obtained with i Bu3 Al and Hex3 Al at 100℃ did not contain isobutene and hexene units.

助催化剂为Et3Al聚合得到聚丙烯链结构中含有少量乙烯共聚单元；而助催化剂为Me3Al， i Bu3Al和Hex3Al聚合得到聚丙烯链结构中没有发现共聚单元。

It provides the link between the theoretical background for limiting the voltage stress on each switching component and the range of voltage variation for an imbricated cell of flying-capacitor multilevel inverter.

并根据单元电压的波动特性，给出了悬浮电容容量的具体选择方法，为保证功率开关承受均衡的阻断电压和有效限制单元电压的波动范围提供了理论依据。

Incurrent research, aiming at the rupture problem engendered in the shooting process of acertain 5.56mm automatic rifle, the strain and stress distributions on the cartridge caseunder the action of axial pull have been analyzed. Based on the theories of elastic-plasticmechanics and contact mechanics, a mathematic and physical model of the cartridge-caseand chamber system has been set up; and based on the platform of the general softwarepackage APDL of ANSYS for finite element analysis, a parameterized model of thecartridge-case and chamber system has also been established. The method for nonlinearFEA has been adopted to analyze the stress distribution on the entire cartridge-case andchamber system, and the method of contact element has been employed to investigate thecontact stress between the cartridge case and chamber, and then the influences of frictioncoefficient and locking space on the static and dynamic stress and strain response of thecartridge case and chamber to the action of power gas have also been discussed. On thebasis of a lot of numerical tests, a kind of element Plane13, which is concentrated incoupled computation of heat and construction, has been used finally to simulate thetransient response of the cartridge-case and chamber system to the power gas. Throughloading the temporary thermal characteristics of explosive gas in the procedure of emulate, the corresponding transient thermal stress distributed on the entire system under thecombined load of transient thermal stress and transient pressure has been obtained. Owingto these comprehensive considerations, the numerical results obtained in this paperrepresent the actual situations comparatively exactly.

本文针对某5.56mm自动步枪在工作中出现断壳的问题，分析了弹壳在轴向拉力作用下的应力应变；基于弹塑性力学及接触理论，建立了弹壳弹膛系统的数学、物理学模型，在通用有限元ANSYS软件的参数化建模工具APDL平台上，建立了弹壳弹膛系统的参数化模型；采用非线性有限元法计算了弹壳弹膛系统的整体应力，引入接触单元法分析弹壳和弹膛的接触压力，探讨了在不同的摩擦系数和不同的闭锁间隙对弹壳弹膛静、动态响应的影响；本文进行了大量的尝试，最后确定采用热、结构耦合单元Plane13，在计算中加载了火药气体的温度历程，成功的获得了弹壳弹膛系统在瞬态的热载荷和瞬态的压力载荷同时作用下弹壳弹膛系统的热应力数值解，考虑因素全面，比较真实的反映了弹壳弹膛系统在火药气体压力和热载荷下作用的情况。

The transfer matrix method is used to carry out the vibration characteristic analysis of the fluid-filled piping system. The transfer matrix of the axial, transversal and torsion vibration of the fluid-filled straight pipe element is presented. And the transfer matrix of the elbow is derived according to the discrete model of the inextensible theory of the curve pipe. The effect of the flexural factor on the elbow's transfer matrix is studied.

基于充液直管的梁模型，考虑液体与管道之间的泊松耦合，详细推导了充液直管单元的轴向、横向及扭转振动传递矩阵；采用弯管不延伸理论的离散模型，将变管离散为一组首尾相连，并成一定角度的短直管单元，通过建立弯管处力平衡方程与连续性方程，建立了弯管平面内振动的传递矩阵，并研究了弯曲因子对传递矩阵的影响。

The material pipe is insertable into the heating device and is able to conduct heat with the close positioning of its shaft against the inner wall.

料管可插入到加热单元内，以便通过其柱身紧贴于加热单元的内壁位置而传导热能。

The amount of ink is the unit BCM WYKO using advanced computer tomography of the interferomter and integrodifferential, as amended, is a net volume of the standard unit of measure.

传墨度的单元BCM，是拔取保守WYKO电脑干涉仪不纬断层扫描增积不合得不入的，是网孔容积的尺度计度单元。

The invention provides a dual redundant CAN bus controller, which is arranged on a crewel CAN bus, characterized in that: two CAN bus transceiving modules, two initializing modules are respectively corresponding to the CAN bus controller module A and CAN bus controller module B; the two CAN bus controller modules are respectively connected to the two CAN bus via a driver shifting control unit; the initializing module is connected to the bus control initializing register for initializing the e CAN bus controller modules; a protocol processing module is connected to the FIFO buffer; the FIFO buffer is connected to the node processor via the logical interface; a intermitting process unit sends the corresponding intermitting control signal to the CAN bus transceiving modules according to the CAN bus controller modules; one path of the CAN bus controller module is directly connected to the protocol processing module; another path is connected to the protocol processing module via the bus receiving buffer.

本发明提供了一种双冗余CAN总线控制器，设置于双线CAN总线上，其特征在于：两个CAN总线收发模块、两个初始化模块分别与CAN总线控制器模块A和CAN总线控制器模块B相对应；两个CAN总线控制器模块通过驱动器切换控制单元分别与两条CAN总线相连；初始化模块与总线控制器初始化寄存器相连，对所对应的CAN总线控制器模块进行初始化；协议处理模块与FIFO缓存器相连；FIFO缓存器通过逻辑接口与节点处理器连接；中断处理单元根据CAN总线控制器模块的控制命令对CAN总线收发模块发出相应的中断控制信号；CAN总线收发模块一路与协议处理模块直接相连，另一路通过总线接收缓存器与协议处理模块相连。

Further more, a conforming interpolater modeled with one-layer solid elements is proposed, obtaining the same simulated result comparing to the one with solid continuum elements when interpolater is thinner than 30mm.

在此基础上，提出连续模面单层实体单元包覆垫层等效模型，当弹性垫层厚度小于30mm时，它和连续模面多层实体单元包覆垫层等效模型有相同的模拟效果。

Based on the fundamental theory of the cable-prestressed steel truss established in paper [1], the inversive iterative perturbation equations which can be used to determine the stiffeness of elements of the prestressed steel truss with elastic supports are put forward by using the principle of matrix perturbation and introducing the concepts of the combined elements and stiffeness factors.

本文基于文献[1]所建立的拉索式预应力钢桁架基本理论，通过引入组合单元和刚度变化因子，利用矩阵摄动原理建立了以结点竖向位移为约束，以确定弹性支承多次张拉预应力钢桁架各类单元刚度为目标的反演摄动迭代方程。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐