圆和

Why?" I questioned in puzzle ment . He smiled and drew a circle on a piece of paper, then made a dot in its circumference and asked me,"Which way is the shortest to reach the symmetrical dot in the circumference from this point?""Diameter , I responded , and with this answer I suddenly realized that I was lucky enough to live a diametrical life , namely, a very smooth life . Since I exposed myself to the research in materials, I have been aspir ing to become a scientist, and God has blessed me with a diametrical life without any waste of time or life.

我问父亲，父亲微笑着拿起手中的圆规在白纸上画了一个圆，在圆周上点下一点，问我道："在同一个圆上的一点到达与之相对称的另一点，什么样的方式是最快的呢""直径"，当答案从我的嘴中脱口而出之时，我猛然间也明白了我的幸运就在于我的直径人生，从我进入物理的领域到今日希望成为一名杰出研究者的理想，上帝让我幸运的获得了走这条直径的机会，没有浪费时间和生命。

The Fresnel lens, also known as the dioptric lens, consists of a central glass disk and concentric glass rings or a central glass band surrounded by parallel glass rings.

一个在中心的玻璃圆片和与之同圆心的层层玻璃圆环，或者中间是一个玻璃带，两边是与之平行的玻璃带状环。

Figure 3 the rink and the dot or reduce the map click here to view all news photo 3 1/4 tiles there are four 50% of the standard that is used to control exposure, proofing, Business card printing and membership card when the layout of the deep and superficial changes. 50% of the standard dot if the angle is large, targejia dot gain, on the other hand if a crane in the four corners, the dot.

图3 目测网不面增不小或放不小图不面击此处查察残部故事图片3）每1/4图块洋有4个50%的尺度不圆网不面，用于把持晒版、打样、制卡和会员卡制作时版面的深浅变冻。50%的尺度不圆网不面如果搭角不小，则网不面增不小，反之如四角脱开，则网不面放不小。

Based on the test results and movement equation established, the relationship between drag coefficient and tubular shape is obtained and the drag force imposed on pipe is calculated.

根据试验结果和建立的运动方程，获得阻力系数与圆管形状的关系，并计算了圆管所受到的拖曳力。

In this paper, a method is proposed to estimate the plastic zone size, by extending the Dugdale model to three dimensional (3D) crack problems and the crack opening displacement at the tip of a sptatial penny shaped crack by combining the Barenblatt Dugdale model with the principle of 3D J integral, then the relationship between J integral and COD is obtained.

将Dugdale模型推广到三维裂纹问题计算了圆盘状裂纹前缘塑性区尺寸，并结合断裂力学中的Barenblat－Dugdale裂纹模型和三维J－积分原理计算了圆盘状裂纹前缘张开位移，得到了J－积分与裂纹张开位移的关系。

An Error Analysis of the Work Cylinder with Errors in Ellipticity and Prismatic Roundness when Located on a V-block ;2. The model of circular form based on V-block ,filter,hardware circuit and software flow are introduced.

在工序间检测的基础上，提出了轴承外圈圆度数字化测量系统方案，并在V形块定位的圆度模型推导、测量系统滤波分析、硬件电路和软件流程图方面做了介绍。

The results show that dynamical ductil-ity dominated final velocity of fragments. During tube expansion, the shear fracture appears preferentially a-long the adiabatic shear bands under positive stress, so the adiabatic shear band determines the size and shapeof fragments. Though the fragmentation behaviour of medium carbon Si - Mn bainific steel is close to that ofsteel 50SiMnVB, medium carbon Si - Mn bainitic steel is an ideal candidate material for the tubular bombs be-cause it is better in dynamical ductility, which can enable the tubes to gain high speeds before fragmentation.

结果表明：材料动态塑性是决定破片最终速度的主要因素；圆管膨胀时外表面形成以剪切为主的裂纹，并向内扩展，接近内表面的绝热剪切带伴随着圆管的膨胀而扩展，并未出现失稳现象，但在正应力的作用下成为优先的断裂通道、决定破片的尺寸和形态；中碳Si-Mn贝氏体钢与50SiMnVB钢的破碎性能相近，但贝氏体钢动态塑性很更好，破碎前的膨胀量较大、更有利于提高破片初速，是弹箭比较理想的候选材料。

A new method relying on the Stroh formulism and the theory of the surface impedance tensor was developed to investigate the dynamic instability of interfacial slip waves.The concept of the surface impedance tensor was extended to the case where the wave speed is of a complex value,and the boundary conditions at the frictionally contacting interface were expressed by the surface impedance tensor.Then the boundary value problem was transformed to searching for zeroes of a complex polynomial in the unit circle...

基于Stroh公式和表面阻抗张量理论，提出了研究界面滑移波动态失稳问题的一种新的方法·该方法将表面阻抗张量概念推广到复波速域，并将摩擦接触界面上的边界条件以表面阻抗张量表示·最终将边值问题化归为求解一个复多项式在单位圆内的根·以弹性半空间与刚体平面相对稳态摩擦滑移为例进行了详细的分析，导出了一个4次复特征方程并讨论了方程在单位圆内解的特性，给出了滑移界面波失稳条件的显式解析表达式

The results showed that the light seiner had decreased continually with the station in marine fishery declining constantly due to development of single trawlers and drift gill net; fishing vessels became large and fishing ground was pushed to deep water,significant development had been achieved in light-source fittings technology; Decapterus maruadsi was dominant in the catch, the percent of Pneumatophorus japonicus increased and Sardinella aurita fluctuated obviously.

结果表明：由于单拖作业和流刺网作业的发展，灯光围网作业持续萎缩，在海洋渔业中的地位不断下降；渔船大型化，渔场向深水推进，灯源配置及集鱼并灯技术取得重大突破；主要渔获物中蓝圆鲹占绝对优势，鲐鱼所占比例有上升的趋势，金色小沙丁鱼年间波动明显，颌圆鲹则快速减少，竹荚鱼近年来产量快速增长。

The axially symmetric torsion of rigid circular shaft of varying diameter embedded in an elastic half space is studied by line-loaded integral equation method, where the problem is formulated by distributions of fictitions fundamental loads PRCHS (point ring couple in half space) along the axis of symmetry in interval of the shaft and is reduced to a one-dimensional and non-singular Fredholm integral equation of the first kind and is easily solved numerically.

弹性半空间；本文用线载荷积分方程法研究嵌在弹性半空间的刚性变直径圆轴的轴对称扭转。利用将"半空间的点环力偶"这一虚的基本载荷沿对称轴的圆轴区间中分布就能使本问题归结为一个一维的非奇异的Ferdholm第一种积分方程，且很易用数值求解。文中给出刚性圆锥，圆柱，圆锥柱嵌在弹性半空间的扭转的数值计算的例并和他人的已知结果相比较。

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