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The theory of accretion disks are important for many astrophysical phenomena, including Quasars, active galatic nucleic, X-ray binary stars, and young stellar objects. The most important branch of accretion djsk theory is the stability properties of djsks. It is widely considered that the luminosity variations of various astronomical objects are associated with the instability of accretion disk. The viscosity plays an important role in the accretion disk theory, and magnetic field exists commonly in astronomical phenomena. A more realistic analysis of the stabihty of the accretion disk should include both the radjal and azimuthal perturbations because of the strong shear of viscous flow.In this paper, according to the luminosity Variations of Various astronomical objects, we study the radial-azimuthal instability of an isothermal with magnetic field. We find that the radial and azimuthal fields B〓,B〓 are mainly responsible for enhancing the instability of the magneto-acoustic modes and non-axisymmetric modes,and that pulsational oscillations are larger in the radial than in the Z direction. The model may be useful in explaining the periodic light variation of FU orionis and. T Tauri stars.

在许多天体物理现象中，例如活动星系核，X-射线双星和年青的恒星理论中，吸积盘理论起着重要的作用，而吸积盘理论中的一个重要分支是吸积盘的不稳定性理论，普遍认为活动天体的周期，准周期光变现象与吸积盘的不稳定性有关，在吸积盘理论中，粘滞起着重要的作用，而磁场是天体物理中普遍存在的现象，对于几何薄吸积盘不稳定性分析，由于强剪切流的缘故，应该包括径向和环向扰动两个方面，本文结合天体物理中的各种周期，准周期光变现象，研究了含磁场的等温薄吸积盘的径向-环向振荡不稳定性，结果表明：磁场的径向和环向分量对磁声模和非轴对称模的不稳定性的增加起着主要的作用，且径向振荡大于轴向振荡，所得结果有利于解释FU Orionis和T Tauri Stars的周期光变现象。

Using poly (4-merhylpentene-l) as a membrane material and cyclohexane, irich-loroethylene, tetrachloroethylene, mixture of cyclohexane and trichloroethylene or tetrachloro-ethylene as solvents, the solution were cast to form homogeneous dense membranes, and the crystalline properties and surface morphology were investigated by DSC and TEM.

以聚4-甲基戊烯-1为膜材质，分别以环己烷、三氯乙烯、四氯乙烯、环己烷/三氯乙烯及环己烷/四氯乙烯为溶剂，研究了这些溶液浇铸膜的结晶性质和表面形态。结果表明，溶剂对PMP的相对溶解能力和挥发速度同所成膜内PMP的结晶形式和结晶度密切相关；不同溶剂体系的PMP溶液浇铸膜的表面形态也不尽相同。

By the mechanism of the electrocyclic reaction, three groups of 4-hydroxy-2-cyclobutenones 4 were designed and synthesized to investigate their behaviors underthe thermolysis conditions Meanwhile, a new procedure for preparation of 2(5H)-furanone 5 Was discovered.

根据电环化反应机理，我们设计了三组不同类型的4-羟基-2-环丁烯酮(4)。通过对4-羟基-2-环丁烯酮(4)进行热解，发现了一种制备2(5H)-呋喃酮类化合物(5)的新方法。

The chapter 6 makes a study on the design and synthesis of new glycosides, which prepared from imidazole, thiazole and tetrazole aglycones mentioned above and glucose derivatives by phase transfer catalysis under the moderate reaction condition.

我们以合成的新杂环化合物作为糖的配基，用相转移催化法合成了25个糖苷类化合物。其中包括4个咪唑氮糖苷，12个含有噻唑环的糖苷，6个含有噻唑环的糖酯，3个四氮唑糖苷。

According to the H NMRstudy, it was found that the protons on the cyclopentadienyl ring of 〓 were not splitted, but when one proton on the cyclopentadienylring was substituted by methyl, that is in〓 complexes, thefour protons on the ring were splitted into four groups,the 〓 between the onesignal and the others is large, the total splitting is over 2ppm. The splittings werealso affected by the halides linked with the titanium, they increase according to theorder of CI, Br, I. By the study of the 〓 Sn NMR, it is found that the chemicalshifts of 〓 are present in low field. It is assume that the large space strain causesthe angles of the tin linked with ligands deviate from the normal tetrahedral anglesresults low field shift for 〓Sn. And by MS study,there were no molecular ions for 〓 complexes in the spectra. However, for 〓 when X=CI,Br,NCO and Ar is tolyl or phenyl group,there were molecular ions,but theirabundances were very small,and no that for the iodide was found.

钛上的卤素对茂环氢的裂分也有影响，依〓，Br，I顺序，卤素对茂环氢的裂分依次加大；通过对〓的研究发现，以上这些化合物〓的化学位移都出现在低场，认为大的空间张力造成的锡的键角偏离正常的锡的四面体键角是造成〓化学位移出现在低场的原因；对这些化合物质谱的研究发现，〓系列化合物得不到分子离子峰，而〓系列的化合物，当X=〓，NCO和苯环上不带取代基或只带甲基时，则出现分子离子峰，但丰度很低，而相应的碘化物和其它化合物则没出现分子离子峰。

The mathematical model of ruled helicoids on torus is constructed and two expression methods of ruled helicoids are discussed.

基于圆柱螺旋面和圆环螺旋线的形成原理，构建了圆环直纹螺旋面的数学模型，讨论了圆环直纹螺旋面的两种表示方法。

For one-dimensional mesoscopic metal rings system in external magnetic field, supposing the system has a symmetry under translation in charge space, the quantum current relation in mesoscopic metal rings is given by solving the eigenvalue equation of the current, the property of quantum current have been investigated and analysed.

针对处于外磁场中的一维介观环系统，假设在电荷空间中具有变换的对称性，通过求解电流算符的本征值方程，给出系统中的量子电流关系，分析和研究一维介观金属环中量子电流的性质。结果表明，量子电流不仅与外磁场、介观金属环参数有关，而且还明显地依赖于电荷的量子化性质

Based on the curvature of substrate and Newton ring ,a simple set for measuring the stress in films is designed,which consists of a He-Ne laser,an extended lens,a convex lens and a travelling microscope with a spectroscope.

文章使用M athem atica描绘牛顿环与迈克耳孙干涉条纹，形象地讨论了两条纹产生机理、环纹中心、环纹级次、非单色光环纹及在测量波长时方法等的差异，使教学过程更具有直观性和生动性，加速教学手段现代化进程

The discovery of evidence of trepanation of Guangrao elongates the history of skull trepanation for 1000 years in China.

广饶的"环钻术"将中国颅骨"环钻术"历史向前推进1000年，这是环太平洋地区时代最早的一例。

In chapter 3,we will consider the automorphisms of triangular matrix algebras over commutative semirings.

利用矩阵的一些性质，克服了环上可逆矩阵在半环中未必可逆的难点，证明交换半环R上的n阶三角矩阵代数Tn的自同构都是内自同构。

What would he tell Judith and the children?

他将怎样告诉朱迪丝和孩子们呢？

I this is at that time, the opinion with peacockish true girl is full of in a heart.

这就是当时的我，一个心中布满虚荣的女孩子真实的想法。