查询词典 difference boundary value problem

Studied present measuring methods" advantages and disadvantages, and presented the necessity and importance of researching propellant transient heat transfer.2.according to 130 and aeronautic 90 rocket projectiles" structure, analysed and acquired physical and mathematical models for propellant transient heat transfer, also designed propellant temperature field simulation units for test.3.acquired discrete transient heat balance equation and temperature calculation program, and gave contrasting curves between experimental temperature values and program calculating temperature values as well as maximum errors and average square root errors between them.4.by programs based on the first class boundary condition, worked out temperature distribution in propellant temperature field simulation units at different time, analysed temperature field distribution law and main elements affecting heat transfer, acquired propellant mass weighted average temperature and one at the half position of propellant maximum thickness as well as maximum errors and average square root errors between them.5.established transient heat transfer mathematical model and temperature calculation program for the third class boundary condition, drew contrasting curves between temperature experimental values and calculation values and gave maximum errors and average square root errors between them, got temperature distribution in the simulation unit at different time and main elements affecting heat conduction, figured out propellant mass weighted average temperature and one at the half position of propellant maximum thickness as well as maximum errors and average square root errors between them.

分析了现有测试方法的优缺点，提出了研究推进剂瞬态导热的必要性和重要性。 2。根据130和航90两种火箭弹的结构，分析得到了推进剂传热的物理模型和数学模型，设计了推进剂温度场模拟实验装置。 3。得到了离散形式的瞬态热平衡方程和温度场计算程序，给出了实验温度与程序计算温度值的对比曲线及其最大偏差与均方差。 4。利用程序求出了第一类边界条件下、不同时刻推进剂温度场模拟装置中的温度分布，分析了温度场的分布规律和影响传热的主要因素，求出了推进剂质量加权平均温度和最大肉厚1／2处的温度时间曲线并给出了两者之间的最大偏差与均方差。 5。建立了第三类边界条件下的瞬态导热数学模型和温度计算程序，求出了温度实测值与计算值的对比曲线并给出了两者之间的最大偏差与均方差，得到了不同时刻温度场模拟装置的温度分布与影响导热的主要因素，求出了推进剂质量加权平均温度和最大肉厚1／2处温度及两者之间的最大偏差与均方差，讨论并确定了能代表130和航90推进剂温度的特征点的位置。

From the composite section, it can be found that some fossils'range zones are too short. Maybe it is caused by the fossils not preserved properly or the samples not collected comprehensively. Most fossils'first occurrence data are later than the ages which are defined by the MIDK4 composite section. It is probably caused by the Foraminifer zones in Tethyan- Himalaya which are not isochronous with other areas. It can also be recognized that there are two major extinction and revival events at the boundary of Cenomanian/Turonian and the boundary of Coniacian/ Santonian. They are coincident with the two Ocean Anoxic Events and can be considered as the typical response by creatures.

在复合剖面上可以发现：一些化石的延限非常短，这可能是由于化石保存不完整或者样品采集不全造成的；大部分化石的首现面年龄值都要晚于MIDK4数据库复合剖面给出的年龄值，这可能是由于特提斯喜马拉雅带与全球其他地区的有孔虫化石带不等时造成的；同时，可以在复合剖面上识别出在Cenomanian/Turonian界线附近和Coniacian/Santonian界线附近存在两次大规模的生物灭绝和复苏事件，这正好与两次大洋缺氧事件发生的时间一致，可以作为缺氧事件的生物标志。

Firstly, the equation for stress intensity factors under static uniform pressure is used as the reference case, and then the weight function for a thick-walled cylinder containing a radial edge crack can be worked out. Secondly, the dynamic stresses in uncracked thick-walled cylinders are solved under internal impulsive pressure by using mode shape function method. The solution consists of a quasi-static solution satisfying inhomogeneous boundary conditions and a dynamic solution satisfying homogeneous boundary conditions, and the history and distribution of dynamic stresses in thick-walled cylinders are derived in terms of Fourier–Bessel series. Finally, the dynamic stress intensity factor equations for thick-walled cylinder containing a radial edge crack subjected to internal impulsive pressure are given by dynamic weight function method.

首先采用静态内压下的应力强度因子作为参考解，得到了带径向边裂纹厚壁圆筒的权函数；然后用振型函数方法推导无裂纹厚壁圆筒在冲击内压下的动应力响应，分析中将相应的弹性动力学方程解分为满足非齐次边界条件的准静态解和满足齐次边界条件的动态解的叠加，利用傅立叶-贝塞尔级数展开，推导出了厚壁圆筒内动应力的响应历程和分布规律；最后由动应力权函数方法导出带径向边裂纹厚壁筒在冲击内压下的动态应力强度因子计算公式。

Methods From the fundamental equation in Laplace domain, using Multiple Reciprocity Method-Boundary Element Method, the integral equations and the boundary integral equations are derived and solved numerically.

方法由 Laplace 变换域中的基本方程出发，利用多重互换边界元方法，得到了积分方程和边界积分方程，并求得数值解。

After making the gauge transformation, the effect of long range interaction is equivalent to twisting the boundary field, and the expressions of the boundary condition are given. The induced model is similar to the one which contans Aharonov-Bohm effect potential.

通过引入与构型相关的酉变换，我们成功地将该系统转化为能够直接求解的类型，得到这种长程相互作用的效果相当于产生扭曲边界场，并给出了扭曲边界的具体形式，指出模型类似于具有Aharonov-Bohm效应势的Bariev模型。

Taking advantage of gauge transformation and dipolar approximation, we qualitatively derive rotating Bose-Hubbard model.Then finite temperature phase boundary between superfluid phase and normal state in rotating Bose-Hubbard model is analytically derived by studying the stability of normal state in rotating bosonic optical lattice.We also analytically prove that as the function of rotation angular velocity the oscillation of critical hopping matrix directly follows the upper boundary of Hofstadter butterfly.

4通过做一个规范变换和偶极近似，定性地推导了旋转Bose-Hubbard模型，并且通过研究正常态不动点的稳定性推广了旋转Bose-Hubbard模型的零温相图到有限温度的情形；另外根据系统有效的能带宽度与旋转速度的关系(Hofstadter蝴蝶)，得到了系统的临界跃迁矩阵随旋转速度的改变展示谐振行为的结论。

Himalaya, which formed on the basement of the Pan-African orogenic event at about 550 Ma BP and experienced Ordovician to Devonian platform sedimentation, was transformed into to a back-arc extensional-rifted zone at the end of the Carboniferous. The Yarlung Zangbo ophiolitic mélange zone is a Mesozoic back-arc spreading basin corresponding to the Gangdise paleo-island arc zone on the south side of the Tethyan Ocean. The Gangdise zone experienced island-arc orogeny in the Late Paleozoic. The very significant differences in geology on both sides of the Bangong Co-Nujiang suture zone suggest that the suture zone is not only the northern boundary of Gondwanaland and the boundary between the Indian (Yunnan-Tibet) stratigraphic realm and the South China (Qiangtang-Sanjiang) stratigraphic realm, but also the relics of subductional collision and final extinction of the Phanerozoic Tethyan Ocean after the breakup of the Neoproterozoic supercontinent Rodinia. The basic point of study of the collisional orogenic processes of the plateau is the structure and composition of the archipelagic arc-basin tectonic realm of three different stages bounded by three rigid paleocontinental blocks (Gondwanaland, Laurasia and Pan-Cathaysian) and the mutual constraining, transformation and coupling of various material movement forms.

喜马拉雅奠基于5.5亿年左右的泛非造山事件基底上，历经奥陶纪至泥盆纪台地沉积，并于石炭纪末转化为印度板块北缘的弧后伸展裂陷带；雅鲁藏布江蛇绿混杂岩带曾是特提斯大洋南侧与冈底斯古岛弧带相对应的中生代弧后扩张盆地；冈底斯带曾经历了晚古生代岛弧造山作用；班公湖-怒江带两侧大量地质特征重大差异表明，班公湖-怒江带是冈瓦纳大陆北界，是印度地层区和华南地层区的分界，是新元古代Rodinia超大陆解体后显生宙特提斯大洋俯冲，消减，碰撞，最后消亡的遗迹。

There are various complex interactive relationships between the original system and the environment system in an expending system; therefore the band boundary becomes a gradational boundary.

在全系统中，由于本体系统与环境系统之间会产生各种各样非常复杂的相互作用关系，因而本体系统的边界就成了一个具有丰富层次的环带边界。

On one hand, the grain boundaries are the sites of microcrack nucleation, microcracks first occur at grain boundary zone, whose propagation type depends on lamellar orientation of both side of grain boundary.

一方面，微裂纹首先萌发于晶界区，其扩展方式取决于晶界两侧片层的取向。

Boundary representation, involves actually drawing the boundary of the model so that it appears on the display of a graphics terminal.

界限表示法，介入实际上得出模型的界限，以便它在图形终端的显示出现。

For the head-teacher of the class said that I had seriously broken the school rules,which led me to a three-day suspend class.

为什么呢？因为我的班主任说我严重的违反了校规，于是让我停课三天。

Many of them believe that the conversion of thousands of working-class folk in England spared that nation from the mass carnage and the tyranny that came with the revolution in France.

他们之中有许多人相信，在英国数以千计的劳工阶级之悔改信主使英国免於遭受如法国大革命所造成的大屠杀和专制暴政。