三维的

By the definition of Darboux type vector and rectifying Darboux type vector ,we constructed the rectifying type developable surfaces and Darboux type developable surfaces and tangential Darboux type developable surfaces ,and study these three developable surfaces relationship with Minkowski slant helices and Minkowski conical geodesic curves. Bying applying the singularity theoerical knowledge, We give a classification of special developable surfaces under the condition of the existence of such a special curve as geodesic.

通过定义三维Minkowski空间中的达布型向量以及修正达布型向量，构造出三维Minkowski空间中的三类可展曲面，即修正型可展曲面、达布型可展曲面和切达布型可展曲面，研究Minkowski斜螺线和Minkowski锥面测地线这两种特殊曲线和这些曲面的关系，并研究Minkowski斜螺线和Minkowski锥面测地线作为这些曲面的测地线的条件下，运用奇点理论的知识，对这三种可展曲面进行奇点分类。

A grating function and a groove function are introduced to determine the structure of a concave grating. Basic ideas for the design of a flat-field concave grating with three stigmatic points are proposed. As a proof of the usefulness of these design approaches, image conditions of the grating with three stigmatic points are developed which concise with other published results and they are more general than those obtained from holographic gratings.

采用与分析三维光栅相类似的级数展开法给出了二维集成凹面光栅的球差、彗差的计算方法，计算中用光栅函数和槽面函数来描述具有任意形状和任意变化周期的光栅，提出了一种具有三个无像差点的平面场型凹面光栅的设计方法，利用该方法推导了三点无像差光栅的成像条件，与文献中用其它方法获得的结果相一致，该结果与全息光栅的成像条件相比，更具一般性。

The comparison of the simulations of the same perturbation in 2D and 3D shows that both are similar before the perturbation arrives at 7 solar radii, and that both have the observed three parts of the classical CMEs. However, the reflecting effect of the adopted boundary conditions at both poles in the 3D simulation has a significant effect on the simulation of more hours, and causes unphysical changes in the polar region, such as the enhancement of density and the change of the magnetic field topology.

从对相同扰动的二维和三维模拟结果的对比来看，在扰动到达7个太阳半径之前，模拟结果相似，都可以模拟出CMEs事件的三部分观测特征，但是三维模拟采用的两极边界条件存在的反射效应，对更长时间的模拟有明显的影响，在两极产生密度增强和磁场位形发生较大变化两个非物理扰动。

On the computer screen is a two-dimensional, and we were able to appreciate the really as like-kind three-dimensional image displayed on the computer screen, because the color gray when different people produce the visual illusion of eyes, while the two-dimensional Perception of three-dimensional images on the computer screen.

是在电脑屏幕上一个二维的，我们能够体会到真正的喜欢实物的三维图像在计算机屏幕上显示的，因为颜色灰时，不同的人产生视觉错觉的眼睛，而两个立体知觉三维图像在计算机屏幕上。

For the problem of Joshi's formula without π in the denominator of vertical seepage resistance term and the treatment of eccentricity as well as the differences between 2-D and 3-D seepage flow field, corresponding improvement method was proposed.

推导出了上下封闭边界中无限大油藏水平井的三维稳态产能解析公式，针对Joshi公式中垂直方向渗流阻力分母上少π的问题，偏心距的处理问题以及简化的二维渗流场与三维渗流场之间的差异问题进行了研究，并提出相应的改进方法。

The regurgitant volume was calculated by temporally integrating the instantaneous flow volume rate of each frame during systole.

建立了基于经食道旋转扫描二维和经胸实时三维超声多普勒血流图像获取方法和图像插值、配准算法获得体数据，经多维重建描述二尖瓣反流速度的空间分布，立体观察返流的时相、方向、反流束长度、面积、体积、空间传播和严重程度等；通过重建反流后的速度场，从血流动力学角度分析了二尖瓣反流的性质，计算偏心反流束的湍流强度，利用反流束角度和湍流强度对计算结果进行修正；基于实时三维彩色多普勒成像技术，利用控制体原理对二尖瓣反流束在反流瓣口横断面的速度分布进行空间与时间积分获得二尖瓣偏心性反流的每搏反流量。

The 1D wave equation inverse scattering problem includes many proce- dures such as time-depth conversion,Z transform,1D spectral fac- torization,reflection coefficient and transmission coefficient,et...

三维波动方程逆散射的关键环节可类比于一维波动方程反问题，一维波动方程逆散射中的时深转换、Z变换、一维谱分解和反射与透射系数等环节，在多维波动方程逆散射或速度横向变化介质逆散射的研究中，被替换为射线坐标系、单程波算子、基于Witt积的多维谱分解和反射与透射算子的平面波响应。

In order to study local scouring field near the pier with sediment control dam ,the 3-D velocity field of the pier in monomer model is subtly measured by ADV velocimeter of Sontek.

采用Sontek公司声学多普勒测速仪对有拦沙坝防护的模型桥墩附近流场进行了精细测量，对桥墩冲刷坑内三维流速分布进行了分析，给出了冲刷坑内三维紊动特征量的分布，分析研究了有拦沙防护坝时桥墩局部冲刷的三个新特点，提出了拦沙坝的适用条件。

In order to study local scouring field near the pier with sediment control dam, the 3-D velocity field of the pier in monomer model is subtly measured by ADV velocimeter of Sontek. This paper analyses the velocity distribution in the scouring pool of pier and takes turbulent strength distribution in different direction. Three new characters for the local scours of piers with the sediment control dam are analyzed and the dam's applicability is brought forward.

采用Sontek公司声学多普勒测速仪对有拦沙坝防护的模型桥墩附近流场进行了精细测量，对桥墩冲刷坑内三维流速分布进行了分析，给出了冲刷坑内三维紊动特征量的分布，分析研究了有拦沙防护坝时桥墩局部冲刷的三个新特点，提出了拦沙坝的适用条件。

In Chapter 3, the prior estimates about the 3-D difference solution and its difference quotients on time space and geometry space are made by means of discrete functional analysis, so that the stability and the convergence of the 3-D difference solution are obtained.

在第三章中，运用离散泛函分析的手段，对三维中子输运方程的差分解及其时间、空间差商进行了先验估计，从而得到了差分解的稳定性和收敛性，也为三维问题的应用研究打下了初步的理论基础。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。