模型理论

Hybrid\\|pencil beam model,which has been obtained by embedding the bipartition model into Fermi\\|Eyges multiple\\|scattering theory,shows the potential broad prospect in clinic because of the good calculation accuracy and efficiency.

d+ k$？' o1 |将双群模型计算的宽束电子的能量沉积与Fermi Eyges理论的侧向解相结合来构造电子笔束模型，即混合笔束模型。由于混合笔束模型的计算精度和效率较好，并且适用范围较大，因此，混合笔束模型展示了在放射治疗临床应用上的可能性。

The calculated results of the discrete model accord with the experimental data well. Compared with a simple continual model, the discrete model is true of the characteristic of the flow in manifold systems, and it also shows the availability of the way to use BP neural networks to measure the key coefficient of the discrete model.

通过离散模型计算得出的结果与实验数据符合良好，说明与简化的连续模型相比，离散模型是一种更为符合并联管组流动特性的理论模型，同时也表明了用BP算法来确定离散模型关键系数的有效性。

What this paper finished mainly work as follows: Five-phase hybrid step motor driver system with fixed-chopping frequency and constant total current driving is fully described. Mathematical model of the system, included the current control circuit, power driving circuit and five-phase hybrid stepping motor is established. The steady modeling of the system is established and studied. Based on the steady modeling of the system, dynamic modeling of the system is studied and single step response characteristic is constructed with MATLAB/Simulink. The simulation results, which is certified by the theory analysis, coincide with the theory analysis.

本文主要完成的工作包括几个方面：对五相混合式步进电动机恒频斩波恒总流驱动系统进行了完整的描述；建立了包括电流控制电路、功率驱动电路以及五相混合式步进电动机在内的恒频斩波恒总流驱动系统的完整的数学模型；基于MATLAB/Simulink建立了恒频斩波恒总流驱动系统稳态仿真模型，并进行了仿真；在建立其稳态仿真模型的基础上，对动态模型进行研究，并借助于MATLAB/Simulink工具建立了恒频斩波恒总流驱动系统单步响应特性的仿真模型并对其单步响应特性进行了仿真研究，仿真结果与理论分析相符。

With the investigation of the domestic and foreign literature systematically, the bases on the domestic and foreign present research and the comprehensive utilizations of the various knowledge of fluid mechanics in porous medium, reservoir engineering, mathematical physics, perforation completion, numerical simulation and so on, this article takes numerical simulation of gas reservoir of water solubility as the research aim which has completed following research works and obtained the corresponding research results: it analyzes the nature of the Water-soluble gas and formation water as well as the influent factors of the solubility through the study of massive materials; It establishes mathematical models three-dimension, the dual medium, the gas-water phase through the way of finite difference in the migration of water-soluble gas, which describes the entire process of release, migration and production in formation, where it considered the problems of variable bubble point; According to the numerical models of gas reservoir of water solubility it provides solution procedure that based on black oil model; It discovers that there will obtain the good effects in the lowly speed of development through simulation; the reinjection of formation water may largely enhance the produce degree of water-soluble gas when we consider reinjection in simulator; It considered the influence of perforated completion on development so as to increase the simulator"s versatility, It discovers that the simulator may reflect the conditions of development when we exanimate he simulator"s reliability with the empirical datum.

本文以水溶性气藏数值模拟研究为研究目标，在系统调研国内外文献、深入分析国内外研究现状的基础上，综合利用渗流力学、油气藏工程、数学物理方法、射孔完井以及数值模拟理论等多方面的知识，完成了以下研究工作并取得相应的研究成果；①通过对大量的资料调研，分析了水溶气、地层水性质、储层地质性质以及影响气体在水中溶解度的因素。②考虑到由于高压产生的大量水力裂缝，采用有限差分方法建立水溶气运移的三维、双重介质、气-水两相全隐式数学模型，该模型描述了水溶气在地层中的释放、运移和采出的整个过程。③在原有黑油模型的基础上，根据水溶性气藏数值模型编制了该数值模型的求解程序，该程序可以求解单重、双重介质两种情况。④通过模拟不同开采速度对水溶气开发效果的影响，发现开采速度较慢的时候可以取得较好的开采效果。⑤在模拟器中考虑了注水对水溶性气藏开发的影响，地层水回注可以大幅度提高水溶气的采出程度。⑥为增加模拟器的通用性，在模拟器中考虑了射孔完井方式对开采的影响。⑦检验模拟器计算的可靠性，发现在使用实验数据对水溶性气藏进行模拟时，模拟器可以很好的反映气藏开发的状态。

All the issues directly or indirectly influence value and price of the NPAs. The methodologies including static and dynamic analysis, micro and macro analysis are applied to address the basic theoretical and specific problems in the research. The analysis on value and price of NPAs can fill some vacancies of the theoretical research about NPAs, and reveal the internal links among current relevant theories about fictitious capital /assets, financial risk, financial crisis, portfolio selection and assets pricing models, assets assessment and evaluation technologies.

不良资产价值和价格分析可填补现行不良资产研究中基础性研究的某些不足，并可将现行与不良资产价值和价格分析相关的理论如金融资产或虚拟资本理论、金融风险理论、金融危机理论、资产组合与资产定价模型以及资产评估技术等有机地联系起来，将现行理论所研究的内容的内在联系表现出来，并在一定程度上弥补现行理论的不足。

Migration of radioactive nuclides in groundwater of porous media is controlled not only by groundwater hydraulics, but also by many other physical, chemical processes. Nuclides transport model coupled chemical equilibrium action is to join convection-dispersion model and multicomponent chemical equilibrium model, it is different from traditional transport model based on K〓 completely in theory.

地下水中核素在多孔介质的迁移过程不仅受到水动力的控制，还受到多种物理化学作用的影响，耦合平衡化学作用的核素迁移模型就是把对流—弥散模型与多组分化学平衡模型有机地结合起来，这种模型与传统的基于K〓值的核素迁移模型在理论上是完全不同的。

With an example, the paper uses finite element program ANSYS to establish three calculating model of the steel-concrete composite open-web floor: the combination finite element method of spatial beam elements and shell elements, the finite element method of shell elements and the combination finite element method of shell elements and entity element.

结合一算例，利用ANSYS有限元软件，建立了组合空腹楼盖的三种计算模型：空间梁单元与壳单元的混合元模型、空间壳单元模型、壳单元和块体单元模型三种理论计算方法，对这三种计算模型作分析对比，得到了静荷载作用下该类结构的内力分布规律及其他一些有价值的结论。

We obtain the risk process involved in this model,the statistical properties of the surplus process,and statistical features of the claim numbers and the probability distribution of the total amount of compensation.The three types of business of the risk model is given when the number of claims obey Poisson distribution and negative binomial distribution.We make a comparison between the risk model built in the thesis and the classic risk models with independent claim numbers when the amount of claims obey Weillbull distribution and Exponential distribution.The results have a good practical significance.

其次，考虑不同险种间的相互关系，建立了一种含有主副理赔的风险分析模型；借助随机过程和经典风险理论，对该风险模型所涉及的风险过程、盈余过程的统计特性以及理赔总额的概率分布、数字特征和矩母函数进行解析研究，给出了主理赔次数服从泊松分布和负二项分布的这种风险模型的具体实例，并在理赔额变量服从Weillbul分布和Exponential分布的情况下，把文中所建风险模型和理赔次数相互独立的风险模型作了比较，所得结果有很好的现实意义。

In short, this explorative study for self-identity concept, theory and practice is for the purpose of (1) trying to unitarily understand self-identity concept, in turn to minutely examine the new development of self-identity theory, and to introduce self-identity theories and research methods in western psychology to domestic psychology in order to cause the interest of domestic psychologist to self-identity thesis; and (2) through the empirical study on self-identity of college student, revealing the meaning of self-identity to student development, and the personality characteristics of self-identity status of student, and the characteristics and influential factors of student self-identity development, and the relationship between student self-identity status and mental health condition in order to provide the measurement of empirical study and systematic study data for self-identity researches, in turn to provide basis of theory and method for setting up the theoretical model of Chinese students self-identity; and (3) making up the gaps in empirical researches on self-identity in domestic psychology, opening up a new research domain in colleges and universities student psychology, and enrich the theory on student development researches.

总之，本文对自我同一性概念、理论和实践进行探索性研究，旨在(1)尝试对自我同一性作整合统一的理解并在此基础上，详细考察自我同一性理论的新发展，试图将西方心理学自我同一性理论的发展引入国内心理学，以引起国内学者更多的关注；(2)通过对大学生自我同一性的研究，揭示自我同一性对大学生发展的含义、大学生自我同一性状态的人格特征、大学生自我同一性发展的特征和影响因素、大学生自我同一性状态与心理健康水平的关系，进而为自我同一性的研究提供实证研究的测量工具以及系统的实证资料，为建立中国大学生自我同一性的理论模型提供理论和方法上的基础；(3)弥补国内自我同一性实证研究的空白，开辟大学生心理学研究的新领域，丰富大学生发展研究的理论；(4)当代大学生自我同一性问题的研究既是青年心理学、教育心理学和学校心理学的重要课题，也能为大学生发展和大学教育实践提供心理学依据，特别是在强调创新教育和推进大学素质教育的今天具有重要的实践意义。

An electromagnetic power steering kinematics model is built combined with the sensor and power equipment"s kinematics characteristic, then according to bond graph theory the bond graph model and diamond model of the electromagnetic power steering system are built based on the kinematics model. They could lead to the system"s transfer function, which is combined with automobile"s two freedom degree model, finally leads to the system"s model in condition with step input of steering wheel.

结合转矩传感器和电磁力发生装置的动力学特性建立了电磁式助力转向系统的动力学模型，然后在系统的动力学模型的基础上根据键合图理论建立了电磁式助力转向系统的键合图模型及其方块图模型，从而导出系统的传递函数，再结合二自由度汽车模型，最终建立了系统在方向盘转角阶跃输入下的模型。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。