查询词典 direct numerical method

Level set method introduced by Osher and Sethian is a numerical method, which translates the problem of evolution of 2-D (3-D) close curve into the evolution of level set function in the space with higher dimension. Level set is an accurate and steady algorithm; it can treat with the change of topology naturally.

水平集方法是由Osher和Sethian提出的一种数值计算方法，它将二维的闭合曲线的演化问题转化为高维空间中水平集函数曲面演化的隐含方式来求解，具有拓扑结构可自然变化、计算精度高、算法稳定的特点。

First, the analytical formula of the spheriform water-bearing structures advanced detection in the whole space is deduced. Based on the analysis of large forward modeling results with finite element numerical simulation method, the apparent resistivity data in 3-D space with tunnel is translated into the data of advanced detection in the whole space with comparison method.

首先，推导出了无限全空间中球体含水构造直流电法超前探测的解析解公式，并在利用有限元数值方法进行正演分析的基础上，借助&比较法&将含隧道腔体的三维空间中超前探测视电阻率数据转换为无限全空间中的数据，并探讨了由MN电极附近电阻率不均匀所造成的干扰以及识别和去除这种干扰的方法。

Variabilis natural type; applied the theory of numerical taxology and cluster analysis method, classified the Q. variabilis of Qinba and Huanglong mountain; ascertained the standard and method of Q. variabilis plus trees selection about 30 ages in Shaanxi province different areas and selected 49 plus trees that were suitable to different areas; used isoenzyme analysis ,through the detection enzyme system of POD,GDH,EST and ADH ect, researched the genetic variation level of Q. variabilis natural populations and heredity construction of different Q. variabilis natural type .The result showed:(1) Q.

本文通过对栓皮栎地理分布的研究，确定了研究栓皮栎天然类型的地理区域；应用数值分类学原理，采用聚类分析方法，对秦巴山区和黄龙山区的栓皮栎天然类型进行划分；确定了陕西省不同地区30年左右栓皮栎优树选择的标准和方法，并选出了适宜不同地区生长的优树49株；采用同工酶技术，通过对POD、GDH、EST、ADH等4个酶系统的检测，研究栓皮栎天然群体遗传变异水平和不同栓皮栎天然类型的遗传结构。

The geology research of carbonate reservoirs in Ordovician of Tahe oilfield showed that many large dissolved vugs and fractures were developed. The spread of the reservoir take on a very heterogeneous state. And the typical fractured-vuggy reservoirs was formed. According to the combination of the various spaces, the formation was divided into vuggy formation, fractured-vuggy formation and fractured formation. The research showed that development of the vug is relevant to the its position on the structure, the fractures, the water surface and the weathering surface. Multi-phase charge and recharge of the oil in the reservoirs resulted in the complexity of the fluid distribution. So the"Bottle Model"was brought forward to explain the movement of the water-oil contact. The special storage space and the complex fluid distribution lead to the unstability of the production and the complexity of the water cut. In order to explain the characteristic of the fracture-vug unit was brought forward and the basic principle and method of the partition of the fracture-vug unit was formed. The classification and evaluation of the units were performed according the reserve and energy. Based on the research of geology characteristic and the fluid flow in the reservoir the comprehensive numerical simulation plan of the fractured-vuggy reservoirs were established. Through the selection of the simulation unit, fluid flow type and parameter equivalent the triple media reservoir simulation model was established. Considering the practical application the model was resolved by the DKR decomposition conjugate grads method. Based on the fine reservoir description of Dsitrict IV of the Tahe oilfield the various space type were classified and combined together. The geology model of Unit S48 was constructed. Two typical single well model was established according to the geology and the dynamic phenomena. Finally the single well model and the Unit S48 were simulated by the triple media reservoir simulator. Via the local grid refinement and coarsening in the simulation good matchs were gained. Based on the results of the simulation the reserve distribution, percent of reserve produced in various space and the natural energy were analyzed. The fluid was storaged in the fractures and vugs mostly and more than 90% the produced oil came from the systems. The energy belonged to the active one. The results of simulation accorded with the fact and showed the validity and practicability the research and the simulator.

塔河油田奥陶系碳酸盐岩油藏的地质研究表明，其储层中发育着很多大型的溶蚀洞、缝，储层的平面展布呈现出极度的非均质性，形成了典型的缝洞型碳酸盐岩油藏，根据各种孔隙介质在储层中的组合，将储层分为了溶洞型、裂缝-溶洞型和裂缝型三类；研究表明溶洞储层的发育和构造位置、裂缝的发育、潜水面和风化面的位置等因素有关；多期充注的油气成藏模式导致了流体复杂的赋存状态，由此提出了所谓的&瓶子模型&，解释生产过程中油水界面的变化；特殊的储集空间类型和流体分布特征导致油田在开发过程中表现出很大的不确定性和含水变化的复杂性，为了合理的解释油气田开发过程中的动态特征，提出了&缝洞单元&的概念，并制定了&缝洞单元&纵横向划分的基本原则和依据及划分方法，并对&缝洞单元&进行了分类和评价；基于地质特征和流体在其中流动规律的研究，提出了缝洞型碳酸盐岩油藏的数值模拟综合解决方案，通过模拟单元的选择、流动类型和参数的等效，建立了三重介质油藏三维三相数值模拟模型，采用不完全LU分解预处理共轭梯度法进行了求解；在塔河油田4区精细油藏描述的基础上，将各种类型的孔隙空间进行了归类组合，建立了S48单元的地质模型；通过对油井生产动态进行分析研究，建立了两类和油井地质、生产动态相对应的单井模型；最后应用三重介质油藏数值模拟软件对单井模型和S48单元进行了数值模拟，通过局部加密和粗化等技术模拟流体流动规律，取得了很好的拟合效果；结合数值模拟结果，分析了各种介质中的储量分布、储量产出的百分比以及地层的能量，认为塔河油田缝洞型油藏中流体绝大多数储集于缝洞系统之中，所产出流体90%以上也来自于缝洞系统，其底水能量属于较充足的类型；模拟结果和油田实际情况符合较好，说明了地质研究和油藏数值模拟研究的正确性。

The mathematics description of the non-spherical lens is the most important problem for the beam shaping system design. A numerical simulating method and its precision analysis are given, and the results indicate that this method is simple, and can be used for the design of LD beam collimating system with non-spherical lens.

非球面柱透镜曲面的数学描述是人们目前关注较多的问题之一，作者使用数值拟合的方法，对其进行了数值拟合并给出了精度分析，结果表明：该方法简单、直观，能够完全满足特定精度的要求，从而可以方便地用于非球面柱透镜的分析和设计。

By the use of CAD method to carry out the research on key problems of three ring typed less teeth difference reducer-the inner and outer gears have to be designed by adopting modified transmission was advanced. And to study a method for carrying out numerical calculation by adopting the powerful functioned mathematical software MATHCAD in the solution of coincidence extent on less teeth differenced internal messing and in iterative computation for equation set of interference coefficient of tooth profile overlapping.

提出用CAD法研究三环式少齿差减速器设计的关键问题―内外齿轮必须采用变位传动的设计，并研究在求解少齿差内啮合的重合度和齿廓重叠干涉系数方程组的迭代计算中，选用功能强大的数学软件MATHCAD进行数值计算的方法。

From this case, in the assessment, the data of several different time intervals are taken and corresponding confidence levels given, and, employing blind values to express monitoring data and perambulating inspection results, the process method of blind information is applied to the practice of comprehesive assessment. With the observation items in Xiaolangdi Project, the influence factors determing the assessment result are described in the form of blind data. The data are processed according to the blind data algorithms and some scientific and reasonable assessment results are acqired, and the process method overcomes the defect of traditional numerical model, viz., too definitive description of information.

基於此，在综合评判中选取多个不同时间段的数据并赋以相应的可信度，利用盲数表达监测数据和巡视检查结果，将盲信息的数学处理运用到土石坝安全综合评判的工程实例中，并运用盲数运算法则进行盲数处理的探讨，得到了有一定参考价值的评判结果，并克服了传统的数学模型信息描述过於绝对化的问题。

The robustness of the control method was discussed. A numerical example shims that the method can get a satisfied result.

仿真算例表明，所提出的基于动柔度修改的控制方法能够达到较为满意的控制效果，并有较好的鲁棒性。

The method of CFD numerical simulation is employed to replace experimental investigation. Hence, STAR-CD of the commercial software is used to simulate the outer flow field and heat transfer performance of integrated heat sink with heat pipes cooled by airflow. It is found that simulated results agree with experimental results well, which indicates that simulation method is reasonable and reliable. Further, simulated computations for different fin thickness, fin pitches and air velocities are performed to analyze their effects on heat transfer performance of heat sink. Finally, a new optimized structure of integrated heat sink with heat pipes is provided to meet future demands for cooling CPU and its heat transfer is also evaluated. For multi-heat source and higher dissipation power of electronic devices, the integrated heat sink with heat pipes attatched fins stagged in different positions of channels is presented and its flow and temperature fields are also simulated to enhance heat transfer. As a conclusion, all mentioned above are useful for the design of heat sink with excellent efficiency of heat dissipation and further research.

应用商业软件Star-CD对CPU集成热管散热器的外部流场和传热特性进行了数值模拟，将数值模拟结果和试验结果对比，验证了所提出的数值计算方法是可靠和可行的；利用此数值模拟方法对CPU集成热管散热器在不同散热翅片间距、厚度和气流速度下散热器的流动与传热性能进行了数值计算，分析了这些参数的变化对散热器传热性能的影响；针对未来CPU冷却的要求，确定了与最优气体流速匹配的最佳翅片间距、厚度的CPU集成热管散热器的新结构；利用试验评测了根据数值模拟提供的新结构开发出的新CPU集成热管散热器的传热性能；最后在场协同强化传热的理论的基础上，对CPU集成热管散热器的散热翅片错位排列来强化散热器的散热，满足未来大功率、多热源的电子元件的散热，为今后进一步优化散热器提供了依据。

All these work are finished above the study of abundant interrelated literatures.b Two-dimensional Poisson equation is solved by both Chebyshev Tau method and Chebyshev Galerkin method, the numerical uncoils are compared with the exact one.

对于二维Poisson方程边值问题，本文分别推导了Chebyshev Tau方法和Chebyshev Galerkin方法的计算公式，实现了相应的数值模拟。

The dissecting of samples in group2 were difficult. The root of pulmonary artery and ascending aorta failed to be unfolded because fibrous tissue was tough, right and left fibrous trigone were too firm to be solved by hand. Cardiac muscle fibers couldn't be stripped along myofibrillar trajectory since they were prone to break because of their friability.

组2的心脏解剖困难，表现为纤维组织坚韧，游离肺动脉非常困难；徒手无法松解左、右纤维三角，肺动脉和主动脉根部的游离非常困难；心肌纤维坚硬、质脆，解剖时容易断离成碎块，无法沿纤维走行方向剥离。

We have battled against the odds in a province that has become increasingly violent.

我们对在一个争夺日益激烈省的可能性。