查询词典 extremal surface

In addition, some modifications on several computational methods are also presented. Using LMTO method the electronic structure of several systems are studied, and some results are obtained. They are: The ideal Nb (100) surface has three surface states, the multi-layer relaxed surface has two surface states. The surface energy of the ideal surface is higher than that of the relaxed surface, that means that the multi-layer relaxed surface is more stable than the former one, which supports the LEED results. The mono-layer relaxed Ag (111) surface is the most stable one among several" stable surface models"presented by several researchers. The surface energy of Ag (111) surface is higher than that of surface Ag (001), which supports some experimental results such as different reaction rate at different surface orientations for the same material. The surafce states of Si (111) surface not only locate near the Fermi level, but also in the valence band, which agrees well with Cohen's conclusion. Si (111)-H is an effective model for analysing the surface states and H adsorbed on the back surface is a good method for improving the convincingness of the results obtained on thinner slab models. The surface stability depends on three different kinds of MoSi〓(001) surfaces, the surface with mono-layer Si is the most stable one, and the surface with Mo at the first layer is the most unstable one among them. These are consistant with the Kemoda's experimental results. The valence bands of clean or K adsorbed CdTe (111) surface agrees well with the synchrotron radiation studies. The surface of CdTe (111) consists of four kinds of surface models which show different surface electronic structures and different surface structure stabilities. The conclusion agrees well with Wu's experimental work. The different absorbed alkali metals on the CdTe (111) surface give different adsorption characteristics which have relations not only with the valence electrons, but also with the core ones of the alkali metals. The electonic structures of Si-C alloys are different from that of Si-Ge alloys, and the energy band gaps of Si-C alloys do not increase linearly with Carbon concentration, our conclusion supports Alexander's results, but conflicts with Soref's one.

现分述如下： LMTO方法及其应用方面：1）通过对Nb（100）表面电子态分析发现清洁理想表面有三个表面态，多层弛豫表面有两个表面态；表面能大小说明多层弛豫表面更稳定，支持了LEED结果。2）通过对采用不同方法获得的几种不同Ag（111）表面稳定结构的表面能计算分析，给出了单层弛豫表面为Ag（111）表面的最稳定结构；从Ag（111）单层弛豫表面和Ag（001）表面的表面能比较，发现了Ag（001）表面表面能要比Ag（111）小的，表明了同种物质不同表面取向将表现出不同物理、化学性质，这是与实验中得出的结论是吻合的，3）通过对Si（111）表面态分析，不仅发现了Si（111）表面不仅具有居于费米能级附近的悬挂键所对应的表面态，而且还有很多表面态位于价带能量范围内，与Cohen等结果一致，H饱和slab模型背表面相当于增加了slab层的厚度，是一有效的变相增加slab层厚的方法，弛豫表面较清洁理想表面价带谱们低能端的少许移动，预示着总能降低，说明弛豫表面较清洁理想表面稳定。4）MoSi〓具有三种表面，从费米能级上态密度值大小得到单层Si表面最稳定，Mo原子为表层原子的表面最不稳定，双层Si原子表面居中的结论，这与Kemoda等人实验结果是一致的。5）通过对CdTe（111）表面表面电子态、表面结构稳定性及表面H、碱金属吸附的电子结构系列研究，不仅得出了CdTe（111）清洁及碱金属K吸附价带谱与同步辐射光电子谱相吻合的结果，而且发现了CdTe（111）表面具有四类不同原子近邻特征，表现出四类不同的表面结构及电子结构特征：不同表面态分布、不同的表面结构稳定性（表层原子与次层原子成三键有一悬挂键的表面要比表层原子与次层原子成一键有三悬挂键稳定（与Wu等人实验结果一致））、不同的H吸附特性。

So two methods are used to remove the local relation. One is that extremal index is introduced to POT model. The analysis showed that the introduction of extremal index improves validity and veracity of VaR based on POT model. Still VaR based on POT model introducing extremal index is invalid in low confidence level. The other is to filter returns series using GARCH model.

为此引入两种方法来消除超阈值的局部相关性：一是将极值指标引入到POT模型中，实证分析发现极值指标的引入不仅改善了POT模型估计VaR的有效性，而且还提高了POT模型估计的准确性，尽管如此在较低的置信水平上即便引入极值指标，POT模型估计VaR仍是无效的；二是用GARCH模型对收益率序列进行过滤处理。

In this thesis, we mainly study one of the topics in graph theory with applications: the extremal values of unicyclic graphs and unicyclic chemical graphs of the first general Zagreb index;the extremal values of bicyclic graphs of the second Zagreb index;the extremal values of unicyclic graphs of the general Randic index.

本论文主要研究了图论及其应用中的一个方面：图论在化学中的应用-单圈图以及化学单圈图的第一广义Zagreb指标的极值，双圈图的第二Zagreb指标的最小值以及单圈图的广义Randi指标在某个范围的最小值。

Extremal mappings have been one of the main topics in the theory of quasiconformal mappings, n the section 4, we consider the extremal mappings on the surface Rwhere every Ri is a hyperbolic Riemann surface, Ri Rj =,i j,I is a non-empty indexset.

拟共形映射的极值问题是拟共形映射理论中的又一重要课题，在文章的第四章中，我们将考虑曲面R=U R_i i∈I上的极值问题，其中每个R为双曲Riemman曲面，R_i∩R_j=φ，i≠j，I为非空指标集。

There are series of papers studying the solvability of an incompressible, viscous, instationary fluid contained in a domian bounded entirely by a free surface. In 1977, Solonnikov proved its local solvability in a Holder space for any initial date but without surface tension. In 1984, he considered the same problem in a Sobolev space with surface tension being taken into account. In I992, Mogilevskii and Solonnikov treated the same problem in a Holder space, where the coefficient of surface tension is not a constant. There are also short-time existence results for the solvability of an incompressible, vicous, unsteady fluid bounded above by a free surface and below by a fixed bottom which approach horizontal planes at infinity. In 1981, Beale proved its local solvability in a Sobolev space for any initial date but without surface tension. In 1983, Allain were concerned with the same problem in R〓 with surface tension but under the assumption that the initial fluid domain was near a horizontal strip. In 1987, he obtained the same result without the preceding assumption. In 1996, Tani solved the same problem in R with surface tension. For the solvability of an incompressible viscous instationary fluid in Ω R bounded inside by a free surface S and outside by a rotating boundary S, in 1995 Ciuperca proved its local existence in a Sobolev space for any initial date but without surface tension. In this paper, we consider the same problem with surface tension.

对于边界完全是由自由边界组成的有界区域中粘性不可压流体的非定常运动问题，Solonnikcv于1977年在忽略表面张力情况下证明了初值问题小时间解在Holder空间的存在性，于1984年在有表面张力情况下证明了初值问题问题小时间解在Sobolev空间的存在性，Mogilevskii和Solonnikov于1992年在表面张力系数可以不是常数情况下证明了初值问题小时间解在Holder空间的存在性；对于上面是自由边界、下面是固定边界且两边界在无限处趋于水平的无限区域中粘性不可压流体的非定常运动问题，Beale于1981年在忽略表面张力情况下证明了初值问题小时间解在Sobolev空间的存在性，Allain于1983年在有表面张力情况下证明了R中初值问题小时间解在Sobolev空间的存在性，但其中假定初始区域近似是个水平条，他于1987年去掉了这个假定得到同样的结果，Tani于1996年在有表面张力情况下证明了R中初值问题小时间解在Sobolev空间的存在性；对于R中内面是自由边界、外面是旋转边界S的有界区域中粘性不可压流体的非定常运动问题，Ciuperca于1995年在忽略表面张力情况下证明了初值问题小时间解在Sobolev空间的存在性，本文考虑了在有表面张力情况下初值问题可解性问题。

In the research of techniques in curved surface reconstruction and feature extraction, the modeling of NURBS interplation curved surface based on rectangular is focused, in which centripetal parameter is applied to construct node vector, the application of interplation method guarantees the accuracy of curved surface construction, bicubic NURBS curved surface is taken as an example to demonstrate the process of curved surface modeling, and the effectiveness of NURBS is approved in application; Meanwhile, the application of feature techniques in reverse engineering is also diSCUSSed, the recognition and extraction method of feature curved surface are investigated, the relationship between feature recognition and the curvature of curved surface is discussed, with the application of linear and non-linear least squares procedure, data fitting of conicoid in ball surface, cylinder surface and cone surface is

以上述的研究工作为基础，根据企业的实际需求选定轻客和重卡作为研究对象完成了基于反求工程的车身改型设计和优化的工程实践，通过工程实践对反求工程各关键支撑技术进行了验证，所开发的新车型也获得了良好的市场反应。

Results 1、 Generally, we can see the original blue and white, shiny, no cracks in the articular surface of the cartilage after the stress increases gradually yellow, surface roughness, cracks appear; when the pressure decreases, the yellowing, rough, the color of the fracture restore gradually and become shiny.2、the shiny smooth surface can be seen under a light microscope, formation, cell distribution, tidy, clear the level of cartilage at the articular surface stress increases, the surface roughness changes, defects, disordered cells, uneven dyeing ; when the articular surface of the pressure gradually decreased, the cartilage gradually repair and the surface of cells at the surface appear only disorder.3、immunohistochemical observation can be seen throughout the observation period, cartilage cells are type Ⅱ collagen expression and expression after 3 weeks gradually weakening, when the seventh week begin to strong gradually.4、 electron microscopy shows that when stress increases the articular surface, the cartilage cells became flat, the cytoplasm in the endoplasmic reticulum, Golgi apparatus decreased with collagen disorders; and when stress decreases the articular surface, cartilage cells gradually returned normal, cytoplasm in the endoplasmic reticulum, Golgi body gradually restore quantity; collagen fibers with a gradual rules.

结果：①大体观察可见到原本蓝白色、有光泽、无裂纹的软骨在关节面压力增大后，逐渐呈灰黄色，表面粗糙，出现裂隙；当压力逐渐减小后，变黄、粗糙、有裂隙的软骨颜色逐渐恢复，变得有光泽②光镜下可见表面光滑、平整，细胞分布均匀、整齐，层次清楚的软骨在关节面压力增大后，表面变粗糙、缺损，细胞排列紊乱、染色不均；当关节面压力逐渐减小后，软骨表面逐渐修复，细胞仅在表层排列紊乱③免疫组织化学观察可见整个观察期内软骨细胞胞浆内均有Ⅱ型胶原表达，术后3周内表达逐渐变弱，从第7周时开始逐渐变强。④电镜下可见当关节面压力增大后，软骨细胞逐渐变扁，胞质中内质网膜、高尔基体减少，胶原排列紊乱；当关节面压力减小，软骨细胞形态逐渐恢复正常，胞质中内质网膜、高尔基体数量逐渐恢复；胶原纤维排列逐渐有规则。

We firstly discuss minimal sets characterizations of closed-set lattice , then systematically study the categorical properties of categories CL and PairCL by the means of the join-semilattices closed-set-latticefies, and the constructions of monomorphism, epimor-phism, extremal monomorphism, extremal epimorphism, section, retraction, subob-ject, quotient object, product, co-product, equalizer, coequalizer, inverse limits and direct limits in the categories CL and PairCL are given.

首先讨论了闭集格的极小集刻划，然后通过并半格的闭集格化这种方法，较为系统地研究了范畴CL及范畴PairCL的性质，给出了范畴CL和范畴PairCL的单态射、满态射、极端单态射、极端满态射、截节、收缩、子对象、商对象、极端子对象、极端商对象等特殊态射和特殊对象的具体刻划，并且研究了它们的等化子和余等化子、乘积和余积、逆极限和定向极限的具体构造。

We firstly discuss minimal sets characterizations of closed-set lattice , then systematically study the categorical properties of categories CL and PairCL by the means of the join-semilattice's closed-set-latticefies, and the constructions of monomorphism, epimor-phism, extremal monomorphism, extremal epimorphism, section, retraction, subob-ject, quotient object, product, co-product, equalizer, coequalizer, inverse limits and direct limits in the categories CL and PairCL are given.

首先讨论了闭集格的极小集刻划，然后通过并半格的闭集格化这种方法，较为系统地研究了范畴CL及范畴PairCL的性质，给出了范畴CL和范畴PairCL的单态射、满态射、极端单态射、极端满态射、截节、收缩、子对象、商对象、极端子对象、极端商对象等特殊态射和特殊对象的具体刻划，并且研究了它们的等化子和余等化子、乘积和余积、逆极限和定向极限的具体构造。

Defined object function can extract the extremal point s located accurately,form the stable extremal regions,and magnify the local intensity changes.

提出了一种基于不变区域提取算法，通过灰度指数变换，定义的目标函数不仅提取了定位准确的极值点，形成稳定的不变区域，而且突显了每个方向上灰度的变化。

This matter overthrew all basises I learned from Sunday school .

这件事把我从周日学校学到的所有道理都颠覆了。

It's one of the cruel ironies of aging: if you want to remember your favorite restaurants, the less you should eat at them.

这是一个老化的残酷讽刺：如果你想记住你最喜欢的餐馆，你应该更少吃到它们。