基本曲线

For the timelike surfaces with constant positive Gaussian curvature (K=1) in R〓, we construct the correspondence between R〓 and sl (2, R), and deduce the fundamental equations for a special choice of the velocity of motion of time-like surfaces in asymptotic coordinates under suitable conditions, meanwhile, we give the B〓cklund transformation and one soliton solution of the evolution equations, then in terms of a gauge transformation we obtain the explict expression of the motion of surfaces.

对于三维Minkowski空间R〓中具有正常高斯曲率（K=1）的类时曲面，取定特定速度，在以渐近线作为坐标曲线的情况下，曲面运动满足两个基本方程，即sinh-Gordon方程和θ随时间演化的方程（其中θ表示两条渐近线之间的夹角），同时给出两个基本方程的B〓cklund变换和单孤子解，并通过规范变换给出相应的正常高斯曲率曲面的显式表达式。

Asimple necessary and sufficient condition for global controllability will bepresented. The analysis method is based on some basic facts in planartopology such as the Jordan curve Theorem, and in the geometric theoryof ordinary differential equations including the Poincare-Bendixson Theo-rem.

分析方法主要是基于平面拓扑中的一些基本事实，比如Jordan曲线定理，以及常微分方程几何理论中的几个基本定理，如Poincare-Bendixson定理，指标定理等。

Result The phenological characteristics of Nandina domestica from different areas and germplasm resources were basically identical; the growth patterns of cultivated type and wild type were also basically identical while the cultivated type grew faster than the wild type; both the two types grew very quickly in young stage while the annual growth of new shoots and the growth patterns of leaves all followed the fitting curve of the Logistic equation.

结果］南天竹各地理种质资源物候特征基本一致；栽培型和野生型生长规律基本一致，但栽培型的生长速度大于野生型；不管是栽培型或是野生型南天竹的高生长在幼龄期都比较迅速，其新梢的年生长、叶片生长规律都遵循Logistic方程的拟合曲线。

Firstly, the mapping of high level programming language to hardware description language is described, some principles of the conversion of algorithm to state machine are also proposed; Secondly, the basic raster graphics algorithms for drawing 2D primitives are introduced, including self-adaptive algorithm of singl...

首先讨论了高级语言描述到硬件描述语言的映射，提出了算法到算法状态机抽象的规律；然后，介绍了现有的基本图形生成算法，包括直线的自适应算法、三角形边相关扫描算法，宽直线线刷子算法及改进的圆形、椭圆的生成算法，同时讨论了加速算法的研究现状；接下来具体讨论了基本图形的硬件实现，给出了各算法的状态机流程图、接口定义和实现框架，并且从理论角度给出了二次曲线加速算法的证明；最后采用EDA工具对VHDL程序进行仿真、综合并实现。

This article mainly simulates gradually damage destruction process of rock, major in determinationg the definition of rock three-dimensional damage tensor, simplify to the damage tensor and obtain its engineering calculation method, and obtains the basic expression form of equivalent stress by equivalent stress assumption, symmetrization to the actual stress, thus obtains construction relation of the festival principle of three-dimensional damage rock mass, finally couples elasticity- plasticity with damage in the finite element equation, with reference to elasticity-plasticity gradually degenerated method thought, simulates rock damage to advance gradually the destruction process in finite element method, draws up elasticity - plasticity and damage coupling two-dimension finite element procedure with the C language in the VC contact surface, by simulating experiment destroyed process, acquires destruction image and the axial load distortion curve of model, agreement with the experimental result.

本文主要模拟岩石渐进损伤破坏过程，确定岩石三维损伤张量的定义，对损伤张量进行简化计算并得出其工程计算方法，采用等效应力假设得出有效应力的基本表达形式，对有效应力进行对称化，得出节理损伤岩体的三维本构关系，在有限元方程中实现弹塑性和损伤耦合；借鉴弹塑性渐进退化方法的思想，采用有限元的方法模拟岩石损伤渐进破坏过程，用C++语言在VC界面编制了弹塑性和损伤耦合的二维有限元程序，通过模拟已有的实验破坏过程，得出模型的破坏图像和轴向荷载变形曲线，与实验结果基本一致。

Modification of Simple Formula on Bonds Yield to Maturity;2. Application of Real Option in the Credit Management of Bonds;3. This paper analyses the investing value and speculating value of covertible bonds according to the features of their liability contracts and stock call option.

从可转换公司债券的债务合约特征和股票看涨期权特征出发，分析了其投资价值和投机价值，从而构造出可转换公司债券的投资收益曲线；阐述了可转换公司债券投资的最小值原理，对其投资收益的评估进行了讨论；分析了影响可转换公司债券的基本因素及其随这些因素而变化的基本规律。

On the basis of the analysis of the transient negative current, a compensated voltage can be generated with multiplying the rms value of the negative sequence transient current of the feeder by a settable compensated reactance, then combined with the magnitude of the zero-sequence voltage to consist of the compounded compensated voltage, which can be utilized to revise the characteristics of the inverse time-delay.

其基本保护采用零序过电压保护，动作时间采用反时限特性；在分析接地故障负序暂态电流分布特点的基础上，利用线路负序电流暂态有效值与一个可整定的补偿电抗相乘，形成补偿电压，并与零序电压幅值合成复合补偿电压，利用该电压对基本的反时限动作特性曲线进行修正，使零序过电压保护具有选择性。

The inverse time delay characteristic is adopted by the basic zero-sequence over-voltage protection. On the basis of the analysis of the transient negative current, a compensated voltage can be generated with multiplying the rms value of the negative sequence transient current of the feeder by a settable compensated reactance, then combined with the magnitude of the zero-sequence voltage to consist of the compounded compensated voltage, which can be utilized to revise the characteristics of the inverse time-delay.

其基本保护采用零序过电压保护，动作时间采用反时限特性；在分析接地故障负序暂态电流分布特点的基础上，利用线路负序电流暂态有效值与一个可整定的补偿电抗相乘，形成补偿电压，并与零序电压幅值合成复合补偿电压，利用该电压对基本的反时限动作特性曲线进行修正，使零序过电压保护具有选择性。

During the investigations, some basic research methods and theories such as mending the end section profile of the screw arbor gear applying the conjugate principle, the milling outline for the screw arbor profile cutter by kineto-synthesis method, establishing the dummy variable model of the screw arbor by the CAD method, the theory of the distributing of the fluid pressure on the screw, the precision analyzing and computing screw profile by the dummy model and FEM method are established.

在研究过程中确立了一些基本的研究方法和基本的理论。如应用共轭原理改进螺杆端截面齿曲线的、利用运动合成的方法研究螺杆成形铣刀廓型、应用计算机辅助设计的方法建立螺杆的虚拟模型、应用牛顿流体理论研究螺杆中的流体压力分布、应用有限元分析计算方法对螺杆做精确分析计算。

For the first time, a screw pile and pile driver system for preventing flood and rushing to deal with an emergency was manufactured. The screw piles of the system is different from screw drills used to sap, and it doesn't push soils out. Analyses, including the screw pile's structural strength analysis and the screw blade's welding analysis, were done by ANSYS, which showed that the screw pile's structural strength is enough and that the distort of the screw blade is small. Testing on the screw pile and pile driver system showed that the system performed stably and could meet the need of preventing flood and rushing to deal with an emergency. A mechanics model of interaction of a screw pile and soil was built, and expressions of torque of screw pile's cylindrical part on the condition of screw pile's crew part being driven into soil fully were gained, then the relation of the torque with screw pitch and out diameter of cylinder, which shows the torque decreases with the screw pitch increasing, and that the torque increases with the out diameter of cylinder increasing, which was according with the experiments of the screw pile's being driven into soils, and thus a screw pile with the best structure was chosen. Experiments of bionic surface showed that, on the condition of certain pressure on the surface, the protruding bionic surface can not reduce adhesion and resistance and that the corrugated bionic surface can reduce adhesion and resistance. An orthogonal experiment of the corrugated bionic surface was done with the factors including the width of protrusion, the space between two protrusions, the trolley's velocity and the vertical surface pressure and with the surface frictional coefficient as the experimental target, and some inclusions were drawn that the best combination of the factors was acquired and that the width of protrusion affected the surface frictional coefficient remarkably.

研制了防汛抢险螺旋桩机系统，提高了沉桩作业效率；利用ANSYS对桩体进行整体结构强度分析以及螺旋叶片的焊接分析，表明桩体结构强度足够，焊接过程中，螺旋叶片的变形小；对整个螺旋桩机系统进行试验，表明该系统性能可靠，工作稳定，作业效率高，能够满足防汛抢险沉桩作业基本需要；建立了螺旋桩桩土作用力学模型，得出螺旋桩沉桩过程中螺旋桩螺旋部分完全进入土体时螺旋桩圆柱部分所受扭矩以及扭矩与防汛抢险螺旋桩的螺旋导程和圆柱外径的关系曲线，表明螺旋桩螺旋部分完全进入土体时螺旋桩圆柱部分所受扭矩随着螺旋导程的增大而减小，随着圆柱外径的增大而增大，这与螺旋桩沉桩试验结论相符合，据此优选出最佳结构的螺旋桩；仿生曲面试验表明，尺寸较小的球冠突起型仿生曲面在一定压力作用下未能起到减粘降阻的作用，而尺寸较大的波纹型仿生曲面相对平板具有一定的减粘降阻作用；以波纹型仿生曲面突起宽度、波纹型仿生曲面两突起之间间距、台车的牵引速度以及叶片表面垂直载荷为因素，以曲面摩擦系数试验指标进行正交试验，寻求出在一定试验条件下最佳因素水平组合；波纹型仿生曲面突起宽度在本试验条件下对曲面摩擦系数影响显著，而其它几个因素对曲面摩擦系数影响均不显著；通过波纹型仿生曲面突起宽度和台车牵引速度的单因素试验，表明曲面摩擦系数随着仿生曲面突起宽度的增大而减小，而随着台车牵引速度的变化基本保持不变，和正交试验结果保持一致。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。