Alkaloids from the Roots of Saccopetalum prolificum

In recent years, an increased interest in the phytochemistry of the Annonaceae has beensparked by the isolation of the antileukemic Annonaceous acetogenin'. Saccopela/umprolificllm (Chun el How) Tsiang (Allnonaceae) is an evergreen tree distributed inHainan Province, P. R. China. The ethanolic extract of the plant exhibited cell growthinhibitory activity (20 ig/ml) against LIZ10 lymphocytic leukemia. A new alkaloid,prolifine (l), was isolated from the roots of S. proldicum, in addition t…     

气相色谱-质谱法分析橡苔浸膏中的挥发性化学成分

用挥发油提取器提取橡苔浸膏中的挥发油 ,利用气相色谱 -质谱法 ( GC- MS)分析了其中的化学成分 ,采用GC峰面积归一化法定量 ,鉴定出 2 4种化合物 ,共占挥发油总量的 83%以上     

Four Triterpene Oligoglycosides from the seeds of Aesculus Chinensis

TheseedsofAesculuschinensisBge.(Hippocastanaceae)havebeenusedasfolkmedicineforthetreatmentofdistensionandpaininchestandabdomenl.Untilnow,thereisnoreportonitschemicalconstituents.Thispaperdescribesstructureelucidationoftwonewcompounds,escinsIVa3andIVb4onthebasisofspectroscopicmethodsandcomparisonwithescinsla1andfo22.Amongthem,EscinlaIwasstudiedbyX-raydistractionanalysis.Compound3,whitepowder,showediRbandsduetocarboxylanda,p-unsaturatedesterat1740,1713and1640cm-'andstrongabsorptionbandsat34…     

Exact Solutions and Coherence Structures of Generalized Breor-Kaup Equations

Using the mapping method based on q-deformed hyperbolic functions, the exact solutions of generalized Breor-Kaup equations are obtained. Based on the solutions, two coherent structures, periodic-branch kink and nonpropagating kink, have been obtained. Moreover, one solitonal interaction form, two line solitons interaction on the kink background, has been found.     

热电子等离子体的耗散漂移不稳定性

在热电子等离子体中,存在密度梯度驱动的低频耗散性漂移波,本文导出了包括等离子体电阻性和粘滞性的漂移波的色散关系。热电子环能降低不稳定性的增长率,减少等离子体的反常输运损失。漂移波被热电子环完全稳定的条件是β_h>4ξ/(1+2ξ)。实验中测量了漂移波的激发区域和振荡特性,观察了热电子环的稳定作用实。验结果与理论分析相符。 关键词：     

A method for structured linear total least norm on blind deconvolution problem

The regularized structured total least norm (RSTLN) method finds an approximate solutionx and error matrixE to the overdetermined linear system (H+E)x≈b, preserving structure ofH. A new separation scheme by parts of variables for the regularized structured total least norm on blind deconvolution problem is suggested. A method combining the regularized structured total least norm method with a separation by parts of variables can be obtain a better approximated solution and a smaller residual. Computational results for the practical problem with Block Toeplitz with Toeplitz Block structure show the new method ensures more efficiency on image restoration.     

分次环的有限正规扩张

本文研究了群分次环的有限正规分次扩张问题．利用经典环论方法，得到一个群分次环与其有限正规分次扩张环之间关于分次Jacobson根和分次素根的关系，同时，给出了分次情形的Cutting down定理和Lying over定理．     

立方半导体中双空位态的电子结构(Ⅳ)——GaAs,GaP中双空位态的电子结构

利用文献[1]中的基本方程组和Vogl等人的紧束缚哈密顿量,计算了以GaAs,GaP为代表的极性半导体中理想双空位的A₁,E态的波函数。计算表明,理想双空位态的波函数在靠近As空位或P空位处的三个Ga原子处具有最大几率,波函数的其余部分随着离缺陷距离的增加而缓慢非单调地递减。 关键词：     

Intermolecular Heterocoupling Reaction between N‐Sulfonylimines and Aliphatic Ketones Promoted by Samarium (II) Iodide

N‐sulfonylimines (1) were induced by samarium(II) iodide to produce radical anion intermediates (2) in situ, which were trapped by aliphatic ketones (4) to afford heterocoupling products β‐sulfonamido alcohols (5) in moderate to good yields under mild and neutral conditions.