extremal surface

extremal surface的基本解释

-

极值曲面

与extremal surface相关的网络例句 [注：此内容来源于网络，仅供参考]

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。

与extremal surface相关的网络解释 [注：此内容来源于网络，仅供参考]

extremal surface：极值曲面

extremal property 极值性质 | extremal surface 极值曲面 | extreme 外项