求解

The caustics phenomena of electromagnetic wave propagation in concave reflector, the singularities of caustics, and the method of

40174032的一部分，得到如下结果：论文分析了利用Maslov方法求解非均匀介质中波动方程高频近似解的基本原理和求解过程，构造了介质系数只在一个方向变化时波动方程高频近似解的通用计算公式。

The solution of the optimal 3-impulse rendezvous is a multi-variable iteration process. For the 3-impulse rendezvous with terminal coastings, the symmetry characteristic of optimal 4-impulse rendezvous was applied to reduce the number of the iteration variables to save the calculation consumption.

三脉冲最优解的求解采用多变量迭代的方法；对于存在端点滑行段的三脉冲最优解的求解，利用四脉冲最优解的对称性，减少迭代变量的数量，降低了计算量。

In this thesis, a simplified two-dimensional implementation of Arch Dam in linear elastics is described.

本文针对拱坝的二维线弹性问题进行求解，计算结果由MATLAB编写的无单元伽辽金法程序运行得出，程序还可以精确求解二维悬臂梁问题。

This article optimizes the iterated method of firing control system of antiaircraft artillery which solves the hitting question, detailed research the procedure solution of firing data and gives the result of firing data frame.

详细研究了射击诸元的求解过程，并给出了高炮火控系统求解射击诸元的程序框图。

In this dissertation the"Penalty"finite element method was employed to compute the velocity of the three-dimensional flow of power-law fluid in a profile die. In order to decrease the needed computer memory and raise the stability of numerical simulation, a set of decoupled methods such as PFEM, pseudo-body force method and transformation of momentum equation to the elliptic equation was developed to establish the general finite element equations to compute the distributions of velocity and viscoelastic stress of the three-dimensional viscoelastic flow of the Phan ThienTanner fluid in a profile die. During numerical simulation of the extrudate swell of the PTT fluid, the flow in the die and out of the die was analyzed separately, which demands less computer memory.

本文建立了求解挤出口模内幂律流体流动速度场的通用三维罚有限元模型；对于非线性粘弹性的Phan Thien-Tanner流体，为了降低模拟计算对计算机硬件的要求，并使模拟计算更加稳定，采用了一种去耦算法，包括罚有限元方法、拟体力方法和动量方程的椭圆类方程转化方法，并建立了求解速度场和粘弹性应力场的总体有限元方程；对于PTT流体的挤出胀大问题，提出了挤出胀大熔体口模内外分离模拟法，这样可以显著降低数值模拟对计算机硬件的要求。

In this dissertation the"Penalty"finite element method was employed to compute the velocity of the three-dimensional flow of power-law fluid in a profile die. In order to decrease the needed computer memory and raise the stability of numerical simulation, a set of decoupled methods such as PFEM, pseudo-body force method and transformation of momentum equation to the elliptic equation was developed to establish the general finite element equations to compute the distributions of velocity and viscoelastic stress of the three-dimensional viscoelastic flow of the Phan ThienTanner fluid in a profile die. During numerical simulation of the extrudate swell of the PTT fluid, the flow in the die and out of the die was analyzed separately, which demands less computer memory. The key techniques used in numerical simulation of the three-dimensional extrusion from dies such as decision of boundary conditions, creation of initial velocity field, selection of penalty factor, high Weissenberg number problem , regeneration of the free surface were studied in detail.

中文题名聚合物异型材口模挤出三维流动研究副题名外文题名 Study on three-dimensional flow of polymer melts during the process of profile extrusion from dies 论文作者涂志刚导师柳和生包忠诩教授学科专业材料加工工程研究领域\研究方向学位级别博士学位授予单位南昌大学学位授予日期2001 论文页码总数148页关键词挤出成型聚合物材料挤出口模聚合物异型材馆藏号BSLW /2003 /TQ320 /9 本文建立了求解挤出口模内幂律流体流动速度场的通用三维罚有限元模型；对于非线性粘弹性的Phan Thien-Tanner流体，为了降低模拟计算对计算机硬件的要求，并使模拟计算更加稳定，采用了一种去耦算法，包括罚有限元方法、拟体力方法和动量方程的椭圆类方程转化方法，并建立了求解速度场和粘弹性应力场的总体有限元方程；对于PTT流体的挤出胀大问题，提出了挤出胀大熔体口模内外分离模拟法，这样可以显著降低数值模拟对计算机硬件的要求。

Simultaneously, the exports of ionization rate and nonionzed concentration are set up as a powerful tool for studying thoroughly the freeze-out effect. dN〓/dp and dN〓/dn are neglected in the linearized equation system of the iteration methods of Newton and Gummel, due to having lower 15 orders or more than dN〓/dn and dN〓/dp, thus the computing effort is cut down with no effect on precision. A new cut-off technique is adopted to accelerate the convergence speed, about twice reduced for Newton iteration method and six times or so for Gummel iteration method. The approximate formulae of Fermi-Dirac statistics are also put forward with simpler form and higher precision. 3. A term dependent on time is added to the electron and hole current succession equations respectively. It is only this model that conservation of charge in transient analysis and alternating small-signal analysis at low temperature can be kept by. 4. The performance of SE-PISCES is explained by the simulation example of PISCES-2B, diode.

研究了低温半导体器件模拟的数值方法：对载流子浓度进行了新的归一化；编制了不考虑掺杂所引进的内建电场时的电离率计算程序；由于低温杂质电离率随偏压状态而变化，为此编制了每次求解迭代时的电离浓度计算程序，并将其插入到求解迭代程序中；同时，设置了杂质电离率和未电离杂质浓度的出口点，为更深入地研究冻析效应提供了有力工具；在Newton迭代法和Gummel迭代法的线性化方程组中忽略了dN〓/dp、dN〓/dn，是因为它们比dN〓/dn、dN〓/dp低15个数量级以上，这样减小了计算量又不影响模拟精度；对Newton迭代法和Gummel迭代法采取了新的截断技术，提高了收敛速度，Newton法迭代法和两次左右，Gummel法减少六次左右；给出了表达式更简单而精度更高的Fermi-Dirac积分近似计算公式。

So we can turn die pricing of die state-owned share to die pricing of die stock on die condition of full-flowing.

于是模型将国有股合理价格的求解问题转换成全流通条件下股票价值的求解问题。

With these conclusions,we present an accurate algorithm to solve the simultaneous inequality of binomial PDF.An optimum solution can be worked out by adopting multivariate half-folded searching algorithm,so that we can get the sampling plan of testability demonstration accurately and quickly.

根据这些结论，提出了求解二项分布的联立不等式的精确算法，在可能的求解区域采用多变量折半搜索的算法，确定联立不等式的最优解，从而可以快速准确地获得测试性验证的抽样方案。

New methods for solving the invariants and state equations of Petri Nets are developed in this paper.

研究了Petri网库所不变式和变迁不变式的一种求解方法，给出了Petri网系统状态方程的求解方法和发射向量的通解形式。

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。