有限模型

Based on the analysis of physics course of heat transfer, the mathematical model of single-phase flow in the rectangular narrow channel is proposed. And the boundary conditions are given to get the unique numerical result. The finite volume method is used to found the discrete scheme of equations. According to the flow of SIMPLER arithmetic, the computing program is developed and the correctness of program is validated.Then the program is used to solve the problem of flow and heat transfer in rectangular narrow channel.The stable two dimension velocity and temperature fields in rectangular narrow channel and plate fuel are obtained.

在明确窄缝流道及燃料板换热物理过程的基础上，建立了描述矩形窄缝内单相流动与换热问题的数学模型，并给出了合理的边值条件；然后利用有限容积法对方程进行离散，根据SIMPLER算法的流程编制了模型求解程序；在验证程序正确性的基础上，对矩形窄缝流动与换热问题进行了求解，得到了矩形窄缝流道和板状燃料元件内部温度场、速度场的二维分布。

It also derives calculation formulas of various dispersed coefficient to set up three-dimensional turbulence model of draft tube and confirm the solving method.

对流场控制方程及三维湍流模型进行了深入的分析与研究，导出了通用微分方程，用有限体积法推导了通用微分方程的离散形式，并导出了各种离散系数的计算公式，建立了尾水管的三维湍流模型，并确定了求解方法。

By queuing theory and method,an attack/defense model of antiship missile and its fire defense system is formed, that is, the M/M/C service system model including limited waiting time, multi-assistants and service for first.

应用排队论的理论和方法，构造了反舰导弹与其火力防御系统的攻防对抗模型，即有限等待时间、多服务员、先来先服务的M/M/C服务系统模型。

The temperature change factor in heat exchange process of engine practical cycle was considered in the model.

模型考虑了发动机实际循环工质吸、放热过程温度变化的因素，比现有的等温换热循环有限时间热力学模型更接近实际循环，模拟精度更高。

The diffusion equation describing the light transportation in two dimensional two layers dental model with finite size is solved by finite element method,and the optical intensity distribution inside the dental tissueis is obtained.

利用有限元方法对光在二维牙齿双层有限尺寸模型中传输的扩散方程进行求解，获取了光能在组织体内部的分布情况，并对牙釉质和牙本质在不同光学参量模型下的光学穿透深度进行仿真分析。

For each strategy, a corresponding exploitation plan of groundwater was designed. Then each designed exploitation plan (except scheme 3) was put into the model for calculation and simulation. The analysis on the forecasting results every plan indicates that:(1) Shuting down the self-provided wells is the most direct and effective method, playing an important role in the land subsidence prevention.(2) The resumption of compressed soil by groundwater artificial recharge is limited. So the artificial recharge can\'t provide essential effect for the resumption of land subsidence, unless the artificial recharge is much more than the groundwater withdrawal.(3) The method of "adjusting the exploitation stratum of groundwater to the shallow" has an obvious effect on the land subsidence prevention.(4)"Sand wells" can increase the leakage recharge for confined aquifer, and thus can slow and prevent the development of the land subsidence.(5) For the groundwater exploitation in Xi\'an, emergency self-provided wells should be managed according to the well spacing of 1600m, 2000m and 1600m, respectively, in the river terrace area, alluvial-proluvial fan area and loess tableland area to exploit the first confined groundwater. Corresponding individual well yield can be set as 2500m~3/d, 1500 m~3/d and 200 m~3/d. Make emergency self-provided wells pump in the dry year and stop pumping groundwater to restore and conserve underground water sources in average years and wet years. In this way, groundwater withdrawal of 162000m~3/d can be obtained to provide for the supplement of water supply in Xi\'an. As a result, the water supply stress can be released in dry years. The groundwater depression formed in the exploiting year can resume in 3-4 years. At the same time, this exploitation manner will not lead to obvious land subsidence.

本文利用所建的模型预测了现状开采条件下未来20年的地下水位和地面沉降的变化，在此基础上，提出了防治西安市地面沉降的五个地下水开采方案，利用所建的地面沉降模型对各个设计方案其进行了模拟和预报，对预测结果的分析表明：①封停自备井是防治地面沉降最为直接和最有效的对策，对防治地面沉降起着最为积极的作用；②采用人工回灌方法使被压缩的土层得到的恢复是非常有限的，对地面沉降不能起到根治作用，只有回灌量明显大于开采量时才能有一定的效果；③&调整开采层次，在浅层取水&对防治地面沉降的效果十分明显；④布设&砂井&可以增加对承压含水层的越流补给量，从而可以有效地缓解和控制地面沉降的发生和发展；⑤对西安市的地下水开采，可在河流阶地区、冲洪积扇区和黄土塬区分别采用1600m、2000m、1600m的井间距布置应急自备井，分别采用2500m~3/d、1500 m~3/d和200 m~3/d的单井开采量，开采第一承压水，在平水年或者丰水年不开采，涵养地下水源，在枯水年启动这些应急自备井开采，在输出分析范围内共可获得162000 m~3/d(5913万m~3/a)开采量，可以有效地补充西安市的供水水源，缓解供水紧张局面，开采年开采导致的下降的水位可在停采3～4年后得到基本恢复，同时，这种开采方式不会造成大的地面沉降量。

Aiming at credit risk of loan portfolios in banks, this paper proposes a surplus process of a loan portfolio, and establishes a ruin model with finite and discrete time. Using this model, we derive the ruin probabilities and their recursive equations for the class with single loan amount and the class with multiple loan amounts.

摘 要：本文针对银行贷款组合中的信用风险，提出了贷款组合的盈余过程，得到了有限离散时间下的一个破产模型；并且利用该破产模型推导出单一贷款额结构和多个贷款额结构下的破产概率及其递归公式。

A theoretical model for ST type pulse tube refrigerator is set up and numerical results are achieved with this physical model.

建立了斯特林型脉管制冷机的理论模型，对其进行了相应的有限差分数值模拟，并运用此理论模型，详细分析了小孔阀和双向进气阀开度对制冷机性能的影响，为实验研究提供理论基础； 2。

And a new mechanism is provided to store the data of OWL in relational database, the hierarchy structures of classes and properties defined in the OWL are also kept through views of the database system. 2、 Proposed a new method of using Finite State Machine and execution tag tree to describe the excution logic of existing grid service and the goal service specified by users, using Deterministic Propositional Dynamic Logic and FSM to determine the composable of goal service and make the composition plan. The computation complex is also discussed 3、 Designed some algorithms to compose existing grid services according to user requirement.

同时提出了一种新的机制，使用关系型数据库来存储OWL定义的实体，使用视图表示OWL中定义的类之间和属性之间的层次关系； 2、提出了使用有限状态自动机和执行标记树，表示网格系统中存在的网格服务和代表用户需求的目标服务的执行概要和逻辑，结合确定性动态命题逻辑，研究了目标服务的可组合性和自动组合模型，并讨论了组合模型的计算复杂度； 3、设计了一种根据用户需求来组合已存在的网格服务的算法。

We present our Monte Carlo results of the random-bond Potts ferromagnet with the Olson-Young self-dual distribution of quenched disorders in two dimensions.By exploring the short-time scaling dynamics,we find the universal power-law critical behavior of the magnetization and Binder cumulant at the critical point,and thus obtain estimates of the dynamic expontent z and magnetic exponent η,as well as the exponent θ.Our special attention is paid to the dynamic process for the q=8 Potts model.

以蒙特卡罗模拟方法对自对耦分布二维随机链q态Potts模型的短时临界行为进行了数值研究，利用初始非平衡演化阶段存在的普适幂指数和有限体积标度行为，数值模拟了在不同形式随机分布时q=3和q=8态Potts模型磁临界指数η和动力学临界指数z，计算结果发现η不依赖于自对偶无序分布的具体形式，从而以数值方法给出了一个关于淬火掺杂自旋系统的临界普适行为的验证。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。