Stationary Harry-Dym's equation and its relation with geodesics on ellipsoid

Harry-Dym's equation (HD) is well-known for its cusp soliton solutions. In this paper, relations are revealed between HD and a completely integrable Hamiltonian system in Liouville sense given by

Essay on gravitation: Present-time variation of Newton's gravitational constant in superstring theories

Superstring theories provide an appropriate framework for studying the time variation of fundamental coupling constants. The present time variation of coupling constants in Superstring theories with currently favorable internal backgrounds critically depends on the shape of the potential for the size of internal space. If the potential is almost flat, as in perturbation theory to all orders, the present value of ¦/G¦ for Newton's gravitational constant is calculable and estimated to be 1×10^–11±1yr^–1, which is just at the edge of the present observational bound for/G. If the potential has a minimum with finite curvature due to unknown nonperturbative effects,/G will become unobservably small. The improvement of the measurement of/G of 1 or 2 orders of magnitude would discriminate between the two situations. Problems with the time variation of other coupling constants are also discussed.This essay received the fourth award from the Gravity Research Foundation for the year 1987-Ed.     

K2NiF4型结构的A2－xSrxBO4(A＝La, Dy, B＝Mn, Fe, Co, Ni)希土复合氧化物的合成

以典型的轻希土镧和重希土镝及碱土金属锶作为Ａ位离子，以过渡金属锰、铁、钴、镍作为Ｂ位离子，合成了Ｋ２ＮｉＦ４型结构的Ａ２－ｘＳｒｘＢＯ４希土复合氧化物，采用粉末Ｘ射线衍射技术考察了反应条件等因素对生成Ｋ２ＮｉＦ４型四方（Ｔ）结构上析影响，实现结果表明，四方结构的形成不仅与几何因素有关，而且与各组分的物理化学性质有关。各个不同的组成，生成四方相的温度范围也有所不同。适当地提高反应温度以及延长灼烧时间     

含R_2dtc配体Mo-Cu化合物的动态~(95)Mo NMR

本实验利用动态~(95)Mo NMR监测Mo-Cu系列化合物的形成过程,对反应CuCl+NaR_2dtc+MoO_nS,摩尔比3:3:1,溶剂为DMF;R=Et,n=0(Ⅰ);R=Me,n=0(Ⅱ);R=Et,n=2(Ⅲ)进行了研究,观察到具有不同簇骼的多种中间产物的存在及随反应进程相互转化等现象。     

硫酸根阴离子对HPMBP及TOA协同萃取镨(Ⅲ)及钕(Ⅲ)的影晌

本文研究了硫酸根阴离子对1-苯基-3-甲基-4-苯甲酰基吡唑酮-5(HPMBP,HL)及三辛胺(TOA)协同萃取镨(Ⅲ)及钕(Ⅲ)的影响。发现在SO_4~(2-)体系中协萃机理为:(LnL_3)_o+(HTOAL)_o(HTOA~+LuL_4~-)_o及(HLnL_4)_o+(TOA)_o(HTOA~+LnL_4~-)_o式中Ln~(3+)=Pr~(3+),下标“o”指示有机相中物种,无下标指示水相中物种。固体萃合物的红外光谱及元素分析数据确证了上述机理。     

载波钝化和钼酸盐后处理对不锈钢钝化膜性能的影响

一般认为交流电对金属的腐蚀过程具有加速作用,但我们发现,在直流电位基础上叠加适当波形、幅值和频率的交流电对不锈钢进行载波钝化,尔后再进行适当后处理可使钝化膜的稳定性提高,我们曾就不经后处理的载波钝化过程进行过探讨,本文着重探讨钼酸盐后处理对载波钝化膜表面状态和化学稳定性改善的作用机理。     

The Electrochemical Investigation of MEH-PPV in Ionic Liquid

Ionic liquids are a new kind of room-temperature molten organic salts. It can be used as solvents in the organic/polymeric syntheses, and some of them are called "green" solvents because of its recyclability1. Ionic liquids possess the superior properties, such as thermal stability up to 200(C, involatility and re-designability(for both cation and anion). The ionic liquid employed in this work is [bmim] [PF6]- ( butylmethylimidazolium hexafluorophosphate ) which is immiscible with water and h…     

Synthesis,characterization and interaction of mixed polypyridyl ruthenium(II) complexes with calf thymus DNA

New mixed polypyridyl {HPIP = 2-(2-hydroxyphenyl)imidazo[4,5-f][1,10]phenanthroline, phen = 1,10-phenanthroline, dmp = 2,9-dimethyl-1,10-phenanthroline, dmb = 4,4-dimethyl-2,2-bipyridine} ruthenium(II) complexes [Ru(phen)₂(HPIP)]²⁺, [Ru(dmp)₂(HPIP)]²⁺ and [Ru(dmb)₂(HPIP)]²⁺ were synthesized and characterized by elemental analyses ¹H-n.m.r., u.v.–vis. spectroscopy and cyclic voltammetry. Their DNA-binding properties were demonstrated by absorption, luminescence titrations, steady-state emission quenching and viscosity measurements. The results suggested that all the examined complexes bind with CT-DNA intercalatively. Methyl groups substituted at the 4,4-positions of bpy has no obvious effect on its DNA binding, whereas substituents at the 2- and 9-positions of phen have an impressive effect on its DNA-binding, as revealed by the decreased binding affinity.     

铁－铜－锰氧化物／海泡石催化剂对苯羟基化为苯酚的催化作用

铁－铜－锰氧化物／海泡石催化剂对苯羟基化为苯酚的催化作用曹声春，黄孟光，李克，杜兴军（湖南大学化工系，长沙４１００８２）关键词氧化铁，氧化钢，二氧化锰，海泡石，负载型催化剂，苯，羟基化，苯酚由苯合成苯酚的现行方法存在着反应步骤多，工艺过程复杂，总转化...