半椭圆的

When the elliptical coaxial line becomes a circular coaxial line, the mode eigenequation of the circular coaxial line can be obtained from the mode eigenequation of the elliptical coaxial line using the asymptotic formulae of angular and radial Mathieu functions.

研究表明：当椭圆退化为圆时，利用角向和径向马修函数的渐进关系，可得到填充多层介质的圆形同轴线的模式特征方程，由此可见，圆形同轴线可看作椭圆形同轴线的特例；当椭圆同轴线内导体半长轴大小为零时，则椭圆同轴线就变成椭圆波导，同样的方法，可得到填充多层介质的椭圆波导模式特征方程。

In order to study the fatigue of pressure vessel commonly encountered problem in engineering with large destructibility , based on the theory of fracture mechanics , the pressure vessel existing original crack was equivalent to the problem of infinite flat with center crack .

为了分析工程中常见的破坏性极大的压力容器疲劳问题，基于断裂力学理论将存在初始裂纹的压力容器等效为无穷远处作用均匀拉应力的含中心裂纹无限大板问题，解出表面半椭圆裂纹和穿透裂纹的应力强度因子；利用断裂判据得到裂纹的临界断裂尺寸；采用Paris表达式对裂纹扩展速率进行描述，推导出初始裂纹在不同裂纹尺寸和形式下的裂纹疲劳扩展寿命。

In this thesis,we study the existence and the regularity of positive classical solution and the existence of the large solutions for a singular semilinear elliptic Dirichlet problem and a semilinear elliptic value problem of second order with gradient terms.

本文研究一类奇异半线性椭圆型方程的Dirichlet问题正的古典解的局部存在性及其正则性以及一类含对流项的二阶半线性椭圆型方程爆破解的局部存在性。

In 1976, the International Astronomical Union revised the definition of the AU for greater precision, defining it as that length for which the Gaussian gravitational constant takes the value 0.01720209895 when the units of measurement are the astronomical units of length, mass and time.

但实际上地球绕日的轨道不是一个圆形，而是一个椭圆形：最初天文单位的定义就是上述椭圆的半长轴的长度。1976年，国际天文学联会把一天文单位定义为一颗质量可忽略、公转轨道不受干扰而且公转周期为365.2568983日的粒子与一个质量相等约一个太阳的物体的距离。

This paper first analyses and summarizes the ststus quo and evolution trend of encryption, some common used cryptograph are introduced, including the algorithms used in symmetric cryptosystem and asymmetirc cryptosystem. We describe the theory of each algorithms and compare the elliptic curve cryptosystem with the other two asymmetric cryptosystems to show the advantages of this algorithm. Second, the principle of ECC is discussed, including the math foundation of ECC, basic conception of elliptic curves, constructiong idea of ECC, operation on the elliptic curve and so on. Third, the current attacks of ECC were analyzed deeply, and an algorithm based on limited prime number field was constructed. We analyzed its realizability in theory, and implement it by using certain function of MIRACL software package. Latter half in this paper, the implementation model of a simple elliptic curve encryption system which based on GF has been introduced. The paper also put a deep analysis on the algorithm of point addition and point multiplication.

本文首先对密码技术的发展现状及其发展趋势进行了分析和综述，详细的介绍了私钥密码系统和公钥密码系统的发展，说明各种算法的原理和优缺点，并给出了一些典型的密码体制的简要分析，重点将椭圆曲线算法与其它几种公钥密码算法比较，说明椭圆曲线算法的优势；其次，探讨了椭圆曲线密码体制的原理，包括椭圆曲线密码的数学基础、基本概念、椭圆曲线密码体制的构造思想等问题；第三作者对椭圆曲线的攻击现状作了详细的分析，针对所使用的大素数域F_p，设计了素数域上安全椭圆曲线产生的算法，从理论上做了可实施性分析，从软件上做了具体实现；在本文的后半部分，提出了一个简单的基于有限素数域上的椭圆曲线加密方按算实现模型，并对SECES中设计的点加和点乘运算进行了深入分析。

In Chapter Four, the surface fracture was studied for a functionally graded plate with a semi-elliptical surface crack under state thermal loading, and studied the influence of crack sizes, aspect ratios and material property on the stress intensity factors along a crack-front under two types thermal loading: calefactive state thermal loading and descent state thermal loading.

第四章研究了含有半椭圆表面裂纹的功能梯度材料板条在稳态温度热载荷作用下的裂纹问题分析，着重考虑了升温载荷及降温载荷作用下应力强度因子在裂纹前沿的分布及材料梯度及裂纹与板的几何尺寸对应力强度因子的影响。

The numerical results indicate that the collimating performances of two lens changed little as the increasing of the refractive index and this made it possible to choose the material of the lens in more field.Theoretically,the radiation angle of laser diode beams in the quick axis can be compressed under 0.1 mrad.

结果表明：这两种柱透镜的准直效率随折射率的变化不大，这在一定程度上提高了透镜材料选择的灵活性；并且理论上，共轴双半椭圆柱透镜可以将半导体激光光束快轴方向的发散角压缩到0.1 mrad量级。

From FEM, the contact stress obeys the semi-ellipse distribution and the Mises stress and shear stress are also consistent with contact mechanics theory, but there exists offset or deflection in the symmetric lines of stress distribution, which originates from tooth bending deformation.

由有限元方法得到的渐开线轮齿的接触应力符合Hertz理论中的半椭圆分布规律，Mises应力和剪应力分布也符合接触力学理论，但应力分布的对称中心存在偏离或者偏斜现象，分析认为，是由于轮齿弯曲变形造成的。

The forms of fatigue cracks in bore of gun barrel are considered as edge cracks and semi-elliptical cracks. The stress intensity factors of gun barrel are calculated using a weight function method under the autofrettaged residual stress, thermal stress and assemblage stress.

3武器身管内表面的疲劳裂纹考虑为边裂纹和半椭圆型表面裂纹两种形式，用权函数方法研究了身管在自紧残余应力、温度应力和装配应力作用下的应力强度因子。

The VCL method and the displacement method are used to calculate the Stress Intensity Factors of semi-elliptical surface crack at the root of pipe screws, on the basis of which a simplified calculating model for screws contact is put forward so as to analyse the fracture intensity for oil drill pipe screw coupling. For the semi-elliptical surface crack with different shape and deep ratio at the root of female and male screws and the corner of male flange, the SIF has been studied systemically under inter-pressure, tension, bend and torsion loads and the approximate formulas encluding the structure parameters of oil drill pipe screw coupling, deep ratio and the shape parameters of surface crack are developed.

对工程实际中的多种石油钻杆接头螺纹连接件，就公螺纹齿根、母螺纹齿根、公螺纹台阶转角处存在的不同形状、不同厚度比的半椭圆表面裂纹，在拉伸、内压、弯曲、扭转多种载荷作用下的应力强度因子作了系统研究，在大量有限元计算基础上，建立了包含接头结构参数、裂纹形状、厚度比在内的近似计算公式。

Plunder melds and run with this jewel!

掠夺melds和运行与此宝石！

My dream is to be a crazy growing tree and extend at the edge between the city and the forest.

此刻，也许正是在通往天国的路上，我体验着这白色的晕旋。