查询词典 boundary value problem

The phase of optical wave can be recovered by the intensity transport equation under the paraxial approximation For the optical system with diffraction limit, it is difficult to get the boundary radical slope of phase and sample in the circular domain boundary when using the intensity transport equation to recover the phase, consequently, we reviewed an algorithm mentioned in the reference ［4］, namely, the equation, computation domain and boundary condition are changed, then the phase is reconstructed by the multigrid method and corrected at last Moreover, the experiment system is set to testify the algorithm, and the recovered phase from the intensity data detected by CCD is compared with the result from phase retrieval algorithm, it is found that the phase reconstruction error can reach 017 λ in the case of non-uniform intensity distribution, as a result, the method is suitable for the phase recovery with low wavefront sensing accuracy.

在傍轴近似条件下，可以利用光强传播方程对畸变波前进行相位恢复。对于衍射受限的光学系统，很难获得相位的边界径向斜率值作为边界条件，此外，要获得精确的圆域边界采样值也并非易事。为了克服上述困难，进一步研究了相位恢复改进方法，即改变了方程的表示形式、计算区域和边界条件，并用多重网格法进行求解获得重构相位，最后再将其修正。为了验证算法的精确性，搭建了实验系统对算法进行实验验证，将由CCD探测的光强分布进行计算得到的相位分布与相位恢复算法的结果进行比较，证明在光强分布非均匀的情况下，该方法恢复的相位均方根误差能够达到017 λ，可以适用于波前传感精度要求不是很高的相位恢复。标签自适应光学相位恢复相位修正光强传播方程 adaptive optics phase retrieval phase correction intensity transport equation

Based on the correlation of the Guadalupian and Lopingian conodont zones of the Salt Range, Pakistan with those of South China, the Amb Formation and the lower part of the Wargal Formation in the Salt Range, Pakistan are Late Guadalupian in age. The Guadalupian/Lopingian boundary is in the lower part of the Wargal Formation, and the Wuchi-apingian/Changhsingian boundary is in the lower part of the Chhidru Formation. The Permian/Triassic boundary is in the Kathwai Member of the Mianwali Formation.

根据华南与盐岭地区瓜达鲁普统和乐平统的牙形类化石带对比，可以确定Amb组和Wargal组底部的时代为瓜达鲁普世晚期，瓜达鲁普统与乐平统的界线位于Wargal组下部，吴家坪阶与长兴阶的界线位于Chhidru组的下部，而二叠与三叠系的界线位于Mianwali组下部的Kathwai段之内。

Compared with the known results,the nonlinearity is allowed to change sign and is involved with the first-order derivative explicitly.In particular,the boundary condition includes the Dirichlet boundary condition and Robin boundary condition.

与现有工作相比，我们所考虑的动力方程不但非线性项可变号，而且包含一阶导数项，所考虑的边值条件更具一般性，比如可以包含Dirichlet及Robin边值条件等。

This invention discloses a preparation method for anti-corrosion rare earth magnet material characterizing that it takes the optimized grain-boundary phase design as the starting point on the basis of a dual alloy method to select Nd base alloy with high crystal forming ability as the assist alloy and reduces the temperature of the press mold blank in a quartz container to room temperature from over grain-boundary phase melting point with the water extraction way to get enough cooling rate and guarantee the non-grain-boundary phase, compared with the material of the same composition prepared by ordinary method, the weightlessness of this invented material reduces over 30% after testing the weightlessness of the material by laying it for 96 hours under 121deg.C, 2 atmosphere and 100% humid environment to show the advanced performance of anti-corrosion.

本发明公开了一种耐腐蚀稀土永磁材料的制备方法，其特征是它在双合金法制备工艺的基础上，以优化晶界相设计为出发点，选取具有较高非晶形成能力的Nd基合金为辅合金，并在烧结回火时将置于耐高温石英容器中的压型坯件，从晶界相熔点以上以水淬冷却的方式降温至室温，以达到足够的冷却速率，确保得到非晶晶界相，根据本发明制得的耐腐蚀稀土永磁材料，通过测量在121℃、2个大气压以及100％湿度环境下放置96小时后材料的失重情况，结果显示本发明得到的材料与常规方法制备的相同成分的稀土永磁材料相比失重减少了30％以上，充分证明其具备了更优越的耐腐蚀性能。可广泛应用于电子、汽车、计算机、电力、机械、能源、环保、国防、医疗器械等领域。

Using the method of blow up lower and upper solutions, the existence and boundary behavior of positive boundary blow up solutions for some elliptic systems of competitive type with singular weight functions are obtained, here the singular weight functions are permitted to be bounded in some parts of the boundary, and to go to infinity or even oscillate in other parts.

利用爆破上、下解方法，本文建立了带奇异权函数的竞争型椭圆方程组正的边界爆破解的存在性和边界行为，这里奇异权函数可以在边界的某一部分有界，而在其他的部分趋于无穷或者震荡。

The modal tests of PCB and PCB assembly (free boundary condition and fixed boundary condition) were carried out. The equivalent elastic modulus and damping parameters of PCB can be gained, and the fixed boundary condition of finite element model was also determined. These will help to the following work.Second, drop impact tests of three different heights were carried out. Strains and acceleration responses of PCB were measured. Failed BGA packages of different test conditions were dyeing, and cross section analysis of failed solder joints was conducted.

针对JEDEC标准试件的局限性，提出了设计便于统计学研究焊点可靠性的试验试件的构想，利用有限元模态分析方法确定并验证了用圆形PCB组件替代JEDEC标准试件的可行性；通过一系列模态试验和有限元模态分析，确定了圆形PCB组件的相关试验参数，这不仅为跌落碰撞下PCB组件有限元模拟确定了较为合理准确的有限元模型，而且为正确地评价跌落碰撞下PCB组件的可靠性问题奠定了基础。2。

The modal tests of PCB and PCB assembly (free boundary condition and fixed boundary condition) were carried out. The equivalent elastic modulus and damping parameters of PCB can be gained, and the fixed boundary condition of finite element model was also determined. These will help to the following work. Second, drop impact tests of three different heights were carried out. Strains and acceleration responses of PCB were measured. Failed BGA packages of different test conditions were dyeing, and cross section analysis of failed solder joints was conducted. It was found in our drop tests that the root cause of lead-free solder joints under drop impact was the combined effect of mechanical shock and PCB bending vibration.

针对JEDEC标准试件的局限性，提出了设计便于统计学研究焊点可靠性的试验试件的构想，利用有限元模态分析方法确定并验证了用圆形PCB组件替代JEDEC标准试件的可行性；通过一系列模态试验和有限元模态分析，确定了圆形PCB组件的相关试验参数，这不仅为跌落碰撞下PCB组件有限元模拟确定了较为合理准确的有限元模型，而且为正确地评价跌落碰撞下PCB组件的可靠性问题奠定了基础。

As the application of the intermediate models is concerned, the works applying the intermediate models to investigate the topographic boundary layer, frontogenesis and low-level frontal structures, and the boundary layer jet are summarized in this article. It is mainly focused on the dynamic characteristics of the Ekman layer and its effect on the low-level structure and circulation of the weather systems illustrated by the models. It is shown that the intermediate boundary-layer models have great potential in illustrating the low level structures of the weather and climate systems as they are coupled with the free atmospheric models.

对于这些Ekman边界层近似理论模型的进一步应用问题，主要回顾和总结了利用上述模型探讨地形边界层结构、大气锋生过程、低层锋面结构和环流以及边界层日变化、低空急流形成等动力学问题的研究，并对这些研究所揭示的Ekman层动力学特征及其对自由大气低层运动的影响进行了分析，结果表明，这些Ekman边界层近似模型可以较好地揭示大气边界层动力学特征，在大气边界层动力学及其与自由大气相互作用的研究上具有重要价值。

In order to develop this local property,this paper presents a method,which uses Fourier Series to approximate the boundary shapes of the shafts with periodic boundary of cross section,and uses the conformal mapping in Theory of Function of a Complex Variable to make the complicated boundary shapes of the shafts map a unit circle.Thus elastic theory can analyze...

本文提出一种方法，其实质是：采用富里埃级数来逼近横截面呈周期性变化边界的轴类零件的边界形状；并应用复变函数论中保角映射原理，将零件复杂的边界形状映像成单位圆，从而使弹性理论可以分析和计算复杂边界轴类零件的应力场；再通过留数的求解实现保角映射的反变换。

Remove row and column' and 'put a big number' have been used for the first boundary;a continuous Regional Identification Function is used on the basis of non-variant nodal virtual flux method for the free surface boundary;Gauss formula is used to make the curved surface integral of the free surface boundary transformed as the difference between volumn integral and other curved surface integral to calculate the integral item on boundaries, which avoiding finding the position of free surface, while the continuous Regional Identification Function is applied to calculate volumn integral and surface integral;Crout and PCG method is used for solusion.

对于已知水头边界，采用"去行去列法"和"置大数法"进行处理；对于自由面穿过的单元，在固定网格节点虚流量法的基础上，引入连续的区域识别函数；对于非稳定渗流中自由面边界积分项，采用高斯公式将求自由面的面积分转化为求体积分与其他面积分之差，避免了求自由面的具体位置，同时在计算体积分和面积分时采用连续的区域识别函数；在解法上，采用直接解法和PCG法。

In the days of sailing vessels the crew were afraid they would be becalmed on the ocean.

在使用帆船的时代，船员们担心他们会因为无风而无法在海洋上航行。

As long as foreign donors pay the PA's salary bill, few expect a new intifada.

只要外国继续为巴权力机构的薪水买单，希望发动新暴动的人便寥寥无几。