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MGM is introduced to solve field distributions in 3-D electron optical systems. The difference equation, the discrete form of Laplace's equation, is deduced in 3-D Cartesian coordinates. In view of the smooth effect, MGM combines Gauss-Seidel iteration with a technique known as coarse grid correction. Formulae for restriction and prolongation are deduced and expressed in terms of tensors.

将多重网格法引入电子光学系统中三维静电场的计算，对三维笛卡尔坐标系中的差分方程，采用高斯-赛德尔迭代法求解差分方程组，并结合迭代过程讨论了粗网格的误差校正技术；在不同网格层之间进行场值的限制和延拓，推导了三维静电场中的限制、延拓公式并以张量的形式表示。

In this algorithm, the direction-of-arrival is assumed to be a discrete random variable with a priori probability density function defined on a set of candidate points. Whether or not the secondary sample is required is based on the a posteriori probability distribution of a set of candidate point"s, which can be calculated from the array received signals. And then, the resulting beamformer is a weighted sum of the beamformers pointed at the latest set of point"s, which are combined according to the value of the a posteriori probability for each pointing direction.

在该算法中，期望信号的波达方向被看作是一个定义在若干候选波达方向上的离散随机变量，由阵列接收信号计算出各候选波达方向的后验概率，并将后验概率的分布作为是否需要进行二次采样的判断标准；随后，对各波达方向上的波束成形权值线性加权，便可得到自适应波束成形器，权系数为各候选波达方向的后验概率值。

The scheme is proven to be forward secure, which is based on the abstrusity of discrete logarithm and square rood modulo composite number problem.

新方案的特点是将当前密钥隐藏在签名中，仅使用与当前密钥有关的信息对消息进行签名，与后继密钥无关，签名的前向安全性基于离散对数和模合数平方根问题的难解性。

Water drops can only accrete on the surface of silicone rubber at discrete form because of its hydrophobicity.

由于硅橡胶表面的憎水性能，水珠只能以分离的形式存在于表面。

The new calculation method of structural surfaces with different scales is given on the basis of block discrete element method in which contacts face to face. Moreover, a new discrete element model for simulating rock and soil blasting problem is built. The elements of new model can be split by itself in the program. There are small scale blocks around the charge, and large scale blocks are adopted in far zone.

在块体离散元面－面接触的基础上，给出不同尺度结构面的计算方法，建立离散元对岩土爆破模拟的计算模型，实现块体白分裂计算程序，在药包附近采用小尺度块体，远区采用大尺度块体，可以更为准确地描述爆破载荷下岩体结构面的尺寸效应。

The new circumstances that the discrete manufacturing enterprise is confronted with are analyzed; the function and configuration of production system is expounded; the research actuality and contents about production system capacity in the discrete manufacturing enterprise are summarized; the main research contents in this paper are developed.2. The calculating and analytical methods about production system capacity are studied systemically, a model to calculate rough-cut capacity instantly in "excel" table style is designed, the means to analyze production capacity in different production mode are brought forth, and the balance tactics of production capacity versus load are put forward.3. The application characteristics used in production system about the methods of Computer simulation and CRP in the MRPII/ERP are analyzed and compared; the advantages of Computer simulation method are pointed out; and the simulation researches aiming at production system capacity are implemented by Ithink simulation software.4. A simulation model is founded under the analysis of production system capacity in the production system background of a firm; the change instances of yield, output rate and WIP in the production system are simulated by the action of procurement cycle, machining time, setup time and so on. 5. The change instances of production capacity in the assembly stage are simulated , and rational employees are obtained.

本文主要进行了以下几个方面的研究：1、分析离散型制造企业面临的新情况，阐明生产系统的功能和结构，对离散型制造企业生产系统生产能力的研究内容和现状进行分析，提出本课题的主要研究内容。2、在系统地研究生产系统生产能力的计算和分析方法后，设计了用Excel表快速计算粗能力的方法；给出不同生产方式下的产能分析方法，并提出产能与负荷平衡的策略。3、比较和分析了MRPII/ERP的能力需求计划方法与计算机仿真方法在生产系统中的应用特点，指出计算机仿真方法的优势，并用Ithink仿真软件对企业生产系统生产能力进行了仿真研究。4、以A公司的生产系统为背景，在对生产系统生产能力分析的基础上建立了仿真模型，模拟了在采购周期、加工时间、调整时间以及返工率、废品率、机械开工率等因素作用下生产系统的产量、产出率和在制品数量的变化情况。5、研究在装配阶段生产能力的变化情况，通过仿真优化后确定合理作业人员数量。

Firstly, two examples, which belong to static analysis and dynamic analysis respectively, were given to show the effectiveness of discrete element method. Then the discrete element method was used to perform dynamic analysis of the Chinese 1 km deep-ocean mining system. The dynamic performance of the entire mining system under different current directions was discussed and compared with that from finite element method.

首先，从静态分析和动态分析两方面，给出2个典型算例，证明该方法的有效性；然后，将离散元方法用于中国1 km深海采矿系统的动力学分析，讨论不同海流方向下整体系统的联动性能，并与有限元方法进行对比。

One difference is that memetics' focus is on the selection potential of discrete replicators, where DIT allows for transmission of both non-replicators and non-discrete cultural variants.

一个不同之处在于，模因论的重点是离散复制物的选择潜力，而双继承理论承认非复制物和非离散文化变体两者的传播。

Secondly, two physical models were constructed, which could model rough surface and describe the features of the earth surface, such as chine, neck, valley and hill, etc. According to difference method, the ""true"" volume of the physical models were measured, which was 13260cm3 and regarded as the analysis foundation of the precision of the volume that was calculate by DEM. The discrete dada of the models on a regular spacing of 1cm were collected by 3SPACE FASTRAK and the DEM was obtained by interpolating the discrete dada through GIS software. Based on the volume of the models calculated by DEM, different interpolating methods (IDW, Spline, Natural Neighbor, and Kriging) and variation of grid spacing of data were compared and their effects on precision of volume calculation were analyzed.

构建了可模仿凸凹不平地形表面的实体模型，该模型能够表征山脊、山尖、山涧、丘陵等地形特征；根据体积差减法测量实体模型的体积作为数据精度分析的体积&真值&，该值为13260cm~3，作为采用DEM进行体积计算的基准值；利用精度为0.08cm的三维数字化仪采集间距为1cm的离散数据点，对离散数据点用GIS软件进行内插处理生成DEM模型，通过DEM计算出模型的体积，探讨不同内插方法(IDW、Spline、Natural Neighbor和Kriging)和数据格网间距变化对体积计算精度的影响。

The discrete-element modeling is a new dynamic modeling method in structural geology and geophysics research. The authors built a discrete element model to simulate the evolution of the fault system in active salt domes. Results show that the fault system undergoes three stages: symmetric deformation stage, asymmetric deformation stage, and complete fracture stage.

离散元模拟是构造地质地球物理研究中一种新的动力学模拟方法，作者通过构建离散元模型，模拟了主动底辟盐构造断裂系统的演化过程，结果表明，该断裂系统的发育主要经历了对称变形、不对称变形、整体破裂三个阶段。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。