不稳定

We estimated the conditional symmetry instability by absolute and geostrophic momentem and comparative potential temperature.

利用角动量和相当位温对条件性对称不稳定进行定性判断，此次降雨过程的确存在对称不稳定和对流不稳定。

Using the output data of a MM4 mesoscale numerical model which fairly well simulated the developing structure and the evolution of the "96.1" snowstorm event over Qinghai Xizang Plateau, a nonlinear and non zonally non parallel basic flow symmetric instability models and simulation system were developed to validate the possible effect of conditional symmetric instability on the formation of the snowstorm process, the results showed that in a developing model of two dimensional nonlinear SI i...

利用"96 。1"青藏高原东北部暴雪过程的较成功的中尺度模拟的输出资料，用非纬向非平行基流中的对称不稳定模式，对"96 。1"暴雪发生发展过程的动力学机制进行了三维基流中二维非线性对称不稳定数值模拟试验。结果表明，ψ场和w场的三维配置与切变线的演变过程相当一致，说明用三维基流中二维非线性对称不稳定可能能较好地描述SI在切变线东伸南移过程中所起的作用。

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。

The surface southeast wind is a condition for the generation of advection fog, but it contributes to the disappearance of radiation fog. The inversion in the radiation fog is thick and strong ,but it is weaker or no inversion in the advection fog. The evolution of stratification from the occurrence to the destruction in the radiation fog is from stable to unstable, while the advection fog from unstable to stable.

底层东南风是平流雾生成的条件，却对应于辐射雾的消亡；辐射雾逆温厚而强，平流雾则为弱的逆温或无逆温；辐射雾生消演变对应于大气层结由稳定发展为不稳定，平流雾则对应于由不稳定趋于稳定。

Secondly, method of Taylor series is used to approximate the slow manifold and the O approximation of the slow manifold is given; slow dynamics such as saddle node bifurcation which has been proven to be the same as that for the full system is analyzed; at the same time, fast dynamics including bifurcation conditions and domain of attractor of the stable equilibrium are also analyzed; the attracting region which consists of the stable manifold of the unstable equilibrium and stable equilibrium is given; we found that when the inner flux decay increases, the domain of attractor is enlarged.

首先，给出了电力系统SMIB模型的时间尺度分解，得到标准的奇异摄动模型；其次，利用幂级数方法，给出了慢流形的O近似M〓，分析了在慢流形M〓上的慢动态，得到了慢子系统的鞍结分支值，并证明此分支值与原系统的鞍结分支值相同；分析了快子系统的平衡点和全局分支的存在条件，给出由不稳定平衡点的稳定流形与稳定平衡点形成的吸引域；并研究内部电压对稳定域的影响，发现稳定域随内部电压增加而扩大；最后给出整个系统的稳定平衡点的近似吸引域。

A simple form of the unstable manifold s for the fixed points not being on the boundary;2. Aim To study singular points, closed orbits, stable manifolds and unstable manifold s of a second order autonomous Birkhoff system.

目的研究二阶Birkhoff自治系统的奇点、闭轨、稳定流形与不稳定流形，方法用常1微分方程的定性方法进行研究，结果与结论给出二阶Birkhoff自治系统的奇点判据、闭轨判据、双曲平衡点判据，得到与其相关的平衡稳定性、稳定流形与不稳定流形等。

In the course of alteration,the unstable elements in supergene zone are leached out in quantity,but the stable ones are relatively enriched.

在蚀变过程中，那些在表生条件下不稳定或较不稳定的元素大量流失，而那些稳定或较稳定元素则很少流失或相对富集。

In the process of analytical solution, the divergent item can be give up according to the physical meaning of the solution. But there is no chance to give up the divergent item in the step-by-step integration method. This is why the numerical solution is unstable.

在比较了含有此发散项的该通解的数值结果与平均常加速度法的计算结果后，发现它们是一致的，从而找到了逐步积分法不稳定的原因，即逐步积分法不能避开方程解集中的不稳定子集（从而导致了一种发散性的不稳定）。

Furthermore, the light and heat stability of carminic acid was studied, and the results showed that carminic acid was stable under the darkness and the scattered rays of indoor, but it was unstable in the sunshine and the incandescent lamp, its aqueous solution was stable even at lower than 90

此外，对胭脂红酸的热、光稳定性进行研究的结果表明：胭脂红酸在遮光和室内散射光的情况下是稳定的，在白炽灯下不稳定，在阳光下极不稳定；在90℃以下胭脂红酸溶液是稳定的。

Staying in sludge with steady organic binding specie and residue specie in sludge, element Cu has such a good stability that it is difficult to be released into environment.

发现Zn元素在几种污泥中的不稳定形态均较高，在污泥农林利用过程中容易被植物吸收利用；Cu元素主要以稳定的有机结合态和残渣态存在于各种污泥中，稳定性较好，在污泥农用过程中不易释放到环境中；Ni元素在几种污泥样品中，稳定态与不稳定形态的比例较为相近。

Objective To investigate the effects of interleukin-1 β converting enzyme gene on the biologic characteristics of ovarian cancer cells.

目的 探讨白细胞介素-1 β转换酶的表达，对卵巢癌细胞生物学特性的影响。

Campylobacter: This illness is the most commonly identified cause of diarrheal illness in the world.

弯曲：这种病是最常见的原因查明腹泻病，在世界上。