量子化学方法研究氯代苯酚类化合物对水生物毒性的构效关系

对20个氯代苯酚类化合物进行了CNDO/2量子化学计算,讨论了化合物电子结构与其对水生物翻车鱼(Bluegill)、花鳉鱼(Guppy)、和虾(Shrimp)半致死量之间的关系,分别获得了表示其构效关系的三个线性方程,它们的显著性均远高于α=0.01水平。结果表明:氯代苯酚化合物苯环上碳原子的兀电荷之和(∑Qπ_R)越大苯环上碳原子的净电荷之和(∑Q_R)越大,或LUMO轨道能(E_(LUMO))越低,均使化合物对Bluegill和Guppy水生物的毒性增大;而化合物苯环上羟基邻位的碳原子的兀电荷布居(P_3)越大,同时HOMO轨道能E_(HOMO)越高,则化合物对Shrimp毒性也越大。据此,可预测氯代苯酚类化合物对上述三种水生物的毒性。     

胶东中生代断裂花岗质岩浆带的Rb-Sr年代学及岩浆源区

胶东南部沿海中生代断裂花岗质岩浆带包含了五个岩石系列。根据各岩石系列的Rb-Sr全岩和矿物等吋线年龄(122—220Ma)可将它们划分为三个岩浆亚旋回(三叠纪、晚侏罗世和早白垩世)。利用锶同位素提供的信息与华北地区太古代变质岩系进行对比,并结合地球物理研究成果讨论各岩石系列的源区,强调岩浆是分别来自上地幔顶部和地壳深部麻粒岩相及角闪岩相岩石的部分熔融。     

THE SIMULATED STORAGE CAPACITY OF FLOOD AND WATERLOGGING IN THE TYPICAL AGRICULTURAL REGION IN JIANGHAN PLAIN

１ＩＮＴＲＯＤＵＣＴＩＯＮＪｉａｎｇｈａｎＰｌａｉｎｉｓｏｎｅｏｆｔｈｅｉｍｐｏｒｔａｎｔｂａｓｅｓｏｆＣｈｉｎａ′ｓａｇｒｉｃｕｌｔｕｒａｌｐｒｏｄｕｃｔｉｖｉｔｙｌｏｃａｔｅｄｉｎｔｈｅｍｉｄｄｌｅＣｈａｎｇｊｉａｎｇＲｉｖｅｒｖａｌｌｅｙｏｆｃｅｎｔｒａｌＣｈｉｎａ．ＴｈｅＪｉａｎｇｈａｎｐｌａｉｎａｐｐｒｏｘｉｍａｔｅｌｙ６．６×１０４ｋｍ２ｉｎａｒｅａａｎｄｏｖｅｒ３０ｍｉｌｌｉｏｎｉｎｐｏｐｕｌａｔｉｏｎｉｓｔｈｅｒｅｎｏｗｎｅｄ“ｃｏｕｎｔｒｙｏｆｆｉｓｈａｎｄｒｉｃｅ＂ｉｎ…     

洞体形变在丽江7级大震前作了正确的中短期预报

洞体形变在丽江７级大震前作了正确的中短期预报陈德福１）何世海２）李旭东１）（１）国家地震局地震研究所，武汉４３００７１２）国家地震局分析预报中心，北京１０００３６）我国的应变型（不跨断层）洞体形变观测，包括地倾斜、重力、应变以及水位固体潮汐等项目，使...     

Ellerman Bombs,Type Ⅱ White—light Flares and Magnetic Reconnection in the Solar Lower Atmosphere

Ellerman bombs and type Ⅱ white-light flares share many common features despite the large energy gap between them.Both are considered to result from local heation in the solar lower atmosphere.This paper presents numerical simulations of magnetic reconnection occurring in such a deep atmosphere,with the aim to account for the common features of the two phenomena.Our numerical results manifest the following two typical characteristics of the assumed reconnection process:(1)magnetic reconnection saturates in-600-900s,which is just the lifetime of the two phenomens;(2)ionization in the upper chromosphere consumes quite a large part of the energy released through reconnection,making the heation effect most significant in the lower chromosphere.The applicationof the reconnection model to the two phenomena is discussed in detail.     

THE EFFECT OF DRAINAGE ON CHEMICALELEMENTS CONTENT OF MARSH

I INTRODUCTIONWetland has very important effect on retainingwater and against drought, regUlating climate, controlling soil erosion and so on ac. Today men often attachimportance to economic effect of wetland reclamation,but neglect and destroy other functions and effectswhich result in blind wetland development, a lot ofwetland degeneration. The area of freshwater wetland inthe 1950s was 134 x 10'ha, but in the 1970s 70% hadchanged into farmland (MITSCH, 1993). The area ofwetland in d…     

作为决策支持工具的地理信息系统的演变

地理信息系统(GIS)界是由多种人组成的集体。林学家、地理学者、地方政府机关、公共服务部门和科学研究工作者都在探讨这同一领域,但方向有所不同。联系的纽带是他们都涉及到空间参照数据,即地球表面上具体地区的属性。     

K-H Instability of Dust Plasma

Areview about K-H instability related to comet tail is presented.The effect of dust graing on KHI is theoretically analysed and relations of critical shear to excit KHI with the properties of dust grains both for sheared ion flow and for sheared dust flow re put out.Their possible application in comet tail is suggested.