蒿属三种药用植物营养器官的解剖学研究

本文对大籽蒿、野艾、椒蒿的营养器官进行了组织形态学的观察.分析了药用植物的解剖学特征与药用成份的贮藏、运输和分泌的关系.并总结出这三种植物的茎与叶的显微结构特征可做为鉴别不同种和药材真伪的依据.     

二环戊二烯基钛(IV)配合物的合成及表征 Ⅰ———水杨酸和阿斯匹林茂钛配合物的合成及表征

选择具有抗菌、抗氧化或抗炎镇痛的药物———水杨酸(HLⅠ)、阿斯匹林(HLⅡ)与具有抗癌活性的二氯二茂钛(Cp2Ti Cl2)在非水介质中反应, 得到两种具有潜在药理活性的茂钛配合物 :Cp2Ti(LⅠ)2,Cp2Ti(LⅡ)2.经过元素分析、摩尔电导、核磁共振氢谱与碳谱、红外及紫外光谱等测试, 表明水杨酸、阿斯匹林均与二氯二茂钛形成含 Ti-O 键的单齿配位的羧酸二取代二茂钛配合物.     

SDiff(2) Toda equation — Hierarchy,Tau function,and symmetries

A continuum limit of the Toda lattice field theory, called the SDiff(2) Toda equation, is shown to have a Lax formalism and an infinite hierarchy of higher flows. The Lax formalism is very similar to the case of the self-dual vacuum Einstein equation and its hyper-Kähler version, however now based upon a symplectic structure on a cylinderS ¹×R. An analogue of the Toda lattice tau function is introduced. The existence of hidden SDiff(2) symmetries are derived from a Riemann-Hilbert problem in the SDiff(2) group. Symmetries of the tau function turn out to have commutator anomalies, hence give a representation of a central extension of the SDiff(2) algebra.     

Electrical and optical properties of amorphous Te40As38Ge10Si12 thin films

Electrical, optical and structural, properties, of Te₄₀As₃₈Ge₁₀Si₁₀ thin films were studied. X-ray diffraction patterns indicate that these films are in an amorphous state. The dark electrical resistivity of Te₄₀As₃₈Ge₁₀Si₁₂ films was measured at room temperature and at elevated temperature. The thermal activation energy E was determined. The optical constants (refractive index n and absorption index k) of such films were determined in the spectral range of 0.5–2.0 m. The absorption coefficient () of this system was also determined using the known equation =4k/. The refractive index n has anomalous behaviour near the absorption edge. Analysis of the absorption spectrum reveals indirect optical transitions. The corresponding forbidden-band width was determined. Its value is approximately twice the thermal activation energy.     

A new quantum group associated with a ‘nonstandard’ braid group representation

A new quantum group is derived from a nonstandard braid group representation by employing the Faddeev-Reshetikhin-Takhtajan constructive method. The classical limit is not a Lie superalgebra, despite relations like x ²–y ²=0. We classify all finite-dimensional irreducible representations of the new Hopf algebra and find only one- and two-dimensional ones.     

Smoothness of Brownian local times and related functionals

In this paper we show that the local time of the Brownian motion belongs to the Sobolev space for any p2 and 0<<1/p. In order to prove this result we first discuss the smoothness and integrability properties of the composition of the Dirac function with a Wiener integral W(h), and we show that this composition belongs to , for any >0 and p>1 such that +1/p>1.     

Convergence rates for the approximations of the solutions to algebraic Riccati Equations with unbounded coefficients: case of analytic semigroups

Summary Approximations schemes for the solutions of the Algebraic Riccati Equations will be considered. We shall concentrate on the case when the input operator is unbounded and the dynamics of the system is described by an analytic semigroup. The main goal of the paper is to establish the optimal rates of convergence of the underlying approximations. By optimal, we mean such approximations which would reconstruct the optimal regularity of the original solutions as well as the best approximation properties of the finite-dimensional subspaces. It turns out that, if one aims to obtain the optimal rates in the case of unbounded input operators, the choice of the approximations to the generator, as well as to the control operator, is very critical. While the convergence results hold with any consistent approximations, the optimal rates require a careful selection of the approximating schemes. Our theoretical results will be illustrated by several examples of boundary/point control problems where the optimal rates of convergence are achieved with the appropriate numerical algorithms.Research partially supported by the NSF Grant DMS-8301668 and by the AFOSR Grant AFOSR 89-0511     

Small transversals in hypergraphs

For each positive integerk, we consider the setA _k of all ordered pairs [a, b] such that in everyk-graph withn vertices andm edges some set of at mostam+bn vertices meets all the edges. We show that eachA _k withk2 has infinitely many extreme points and conjecture that, for every positive , it has only finitely many extreme points [a, b] witha. With the extreme points ordered by the first coordinate, we identify the last two extreme points of everyA _k , identify the last three extreme points ofA ₃, and describeA ₂ completely. A by-product of our arguments is a new algorithmic proof of Turán's theorem.     

Dirichlet norms,capacities and generalized isoperimetric inequalities for Markov operators

We define the notion of p-capacity for a reversible Markov operator on a general measure space and prove that uniform estimates for the ratio of capacity and measure are equivalent to certain imbedding theorems for the Orlicz and Dirichlet norms. As a corollary we get results on connections between embedding theorems and isoperimetric properties for general Markov operators and, particularly, a generalization of the Kesten theorem on the spectral radius of random walks on amenable groups for the case of arbitrary graphs with non-finitely supported transition probabilities.