Huperzine H, a New Lycopodium Alkaloid from Huperzia serrata

Huper:iaserrata(Thunb.)Trev.isoneofthemostcommonlyusedtraditionalChineseherbalmedicinesforthetreatmentofcontusions,strains,swellingsandschirophremas'etc..Manylycopodiumalkaloidshavebeenisolated2'3fromitincludinghuperzineA,acompoundwhichhasshownpotentialeffectsonAlzheimedisease.Inourinvestigations.threenewlycopodiumalkaloidswereobtainedandreported"'.ThispaperdealswiththeidentificationofhuperzineH--anewlycopodiumalkaloidwithanovelskeleton.HLlperzineHiscolorlessneedleswithIQ].-216(c0.02.CHC…     

Synthcsis, Structure and Magnetochemistry of a New Hexanuclear Manganese Oxide Complex of the Formula [Mn_6O_2 (O_2CPh)_(10)(CH_3CN)_4]

Manganesecomplexeswithnuclearitiesupt0l8havebeenreported',whichhasbeenstimulatedbyanumberoffactors.TheseMn.sh0wnewandingeni0usstructures.Tetfa'nuclearclustersmaybethemodelsofthephotosyntheticwateroxidationcenter(W0C)ingreenplantsandcyarobacteria'.Thep0ly-nuclearmanganeseclustersexhibit,indeed,highlyunusualmagneticproperties.They0ftendisplayhighspin(S)valuesinthegr0undstate3andcertaincomplexeshavebeenidentifiedasbeingabletobemagnetizedbel0wacriticaItemperaturei.e.,theycanberegardsas"single-mo…     

地质工程自动监测硬件系统若干技术问题

地质工程自动监测系统具有监测对象信息变化差异大,监测环境恶劣等显着特点。其硬件系统须具备监测范围广,抗干扰能力强,抗雷击等特殊功能。同时,为了适应现代化工程建设的要求,还应具备先进的智能化和网络化等功能。为此,本文对地质工程自动监测系统的功能和组成、当前的发展趋势及所涉及到一些关键硬件技术问题展开了讨论,着重总结了作者有关地质工程自动监测硬件系统关键技术问题的研究。最后介绍了作者为五强溪水电站边坡工程建立的自动监测系统,以及该系统双端防雷保护和模块化信号调理等难题的解决。     

认知空间上的智能系统FDSS

智能系统ＦＤＳＳ是直接构造出表现模糊逻辑的一套硬件。作为专家系统的核心,可以通过从经验规则而来的分立电子线路模块与计算机接口相缝合,达到使形式化知识及非形式化知识融溶一体,综合运用的目的。     

Semi-invariants of canonical algebras

We describe the algebras of semi-invariants on the varieties of regular representations of canonical algebras. In particular, we show that these algebras are polynomial algebras or complete intersections. Received: 29 March 1999     

氧化锆填料的高效液相色谱性能评价

研究了采用溶胶－凝胶技术制备的４－６μｍ粒径氧化锆微球的晶体结构,比表面积,孔容,孔径分布及表面酸碱性,测得氧化锆以单斜相和四方相２种相存在。微球的比表面积为２１ｍ６２／ｇ;总孔容为０．１２８０ｃｍ＾３／Ｌ;平均孔直径为８．６ｎｍ。氧化锆的表面存在酸碱两性。分别以异丙醇／环己烷,二氧甲烷／环己烷及三氯甲烷／环己烷为流动相研究了苯酚衍生物,芳香烃衍生物及苯胺等碱性化合物的保留行为。     

Sensitive equilibria for ergodic stochastic games with countable state spaces

We consider stochastic games with countable state spaces and unbounded immediate payoff functions. Our assumptions on the transition structure of the game are based on a recent work by Meyn and Tweedie [19] on computable bounds for geometric convergence rates of Markov chains. The main results in this paper concern the existence of sensitive optimal strategies in some classes of zero-sum stochastic games. By sensitive optimality we mean overtaking or 1-optimality. We also provide a new Nash equilibrium theorem for a class of ergodic nonzero-sum stochastic games with denumerable state spaces.     

On the structure of periodic modules over tame algebras

We describe the structure of stable tubes in the Auslander-Reiten quivers of tame algebras formed by indecomposable modules which do not lie on infinite short cycles. In particular, we prove that all algebras whose module categories have no infinite short cycles are of linear growth.

     

Editor's Note

General Relativity and Gravitation -