Studies on Chem icalCom position ofIron-m olybdenum Cofactor fromNitrogenase by Fluorescence Analysis

ＩｎｔｒｏｄｕｃｔｉｏｎＮｉｔｒｏｇｅｎａｓｅｆｒｏｍａｖａｒｉｅｔｙｏｆＮ２－ｆｉｘｉｎｇｏｒｇａｎｉｓｍｓｉｓｃｏｍｐｏｓｅｄｏｆｔｗｏ－ｃｏｍｐｏｎｅｎｔｐｒｏｔｅｉｎ，ＭｏＦｅ－ｐｒｏｔｅｉｎａｎｄＦｅ－ｐｒｏｔｅｉｎ．Ｆｅ－ｐｒｏｔｅｉｎｃｏｎｔａｉｎｓａｓｉｎｇｌｅＦｅ４Ｓ４－ｃｌｕｓｔｅｒ，ｗｈｉｃｈｈａｓｔｈｅｆｕｎｃｔｉｏｎｏｆｔｒａｎｓｆｅｒｉｎｇｅｌｅｃｔｒｏｎｓｆｒｏｍｄｏｎｏｒｔｏＭｏＦｅ－ｐｒｏｔｅｉｎ．ＭｏＦｅ－ｐｒｏｔｅｉｎｃｏｎｔａｉｎｓＰ－ｃｌｕｓｔｅｒｐａｉ…     

α-Oxo Ketene Dithioacetals Chemistry-A Facile Route to the Synthesis of Fused Heterocyclic Compounds

Q-Oxo ketene dithioacetals and related compounds are versatile synthons in organicsynthesis'-'. The substitution reaction of or-oxo ketene dimethylthio acetals with diamineis one of the impel'tant applications for the synthesis of corresponding a-oxo ketenecyclic N, N-acetals. Junjappa and co-workers described this reaction ill a review'.However, since some kinds of ketene dimethylthio acetals are not easy to prepare, themethod melltioned above is limited. Zhu and co-workers had successfully…     

A Novel Synthesis of Methyl 4, 6-O-Benzylidene-α-D-Glucopyranoside 2, 3-Cyclic Phosphite Ethyl Ester

Itiswellknownthatnearlyallthebiochemicalmetabolicprocessesofcarbohydratesinlivingorganismsinvolvetheparticipationofphosphorus.Forexample.glycosylphosphatesareofgreatsignificanceforthebiologicalactivityofglycoconjugatesandcanserveasintermediatesinbiologicalglycosyltransfer.Theyarealsoofgreatimportanceasglycosyldonorsinpreparationofoligosaccharides,whichareconstituentsofbiologicallyimportantcompoundssuchasantibiotics,glycolipids,glycoproteins.andimmunodeterminants'.Hencetheinvestigationofphospho…     

Gnetifolin L and O, Two Dimeric Stilbenes from Gnetum Montanum

GnetuI)1monlanlImgr0wsinthes0uthernpart0fChinaandhasbeenusedf0rthetreatment0fbronchitisandarthritisinf0lkmedicinel.Previously,aninvestigationofthisspeciesledt0theis0lationofs0meaIkal0idsanddibenzyletherderivatives2.lnourstudies,tenc0mp0nentsincludingresveratr0l,is0rhapontigenin,daucoster0l,O-sitosterol,stearicacid,gnetif0linE,gnet0l,is0rhapontigenin-3-O-6-gluc0pyra(-)8-viniferinandgnetifolinCwere0btainedfromthisplant'.Inthefurtherstudy,f0urnewdimericstilbenesnamedgnetif0IinMandN',gnetifoli…     

A New Lignan Glucoside from Lancea tibetica

L.tibeticaHook.f.etThorns.isanimportantTibetanmedicineusedfortreatmentofmanydiseases'.Thelignanglycosidesandtriterpenesfromthisplanthavebeenreported"'byHuidiZhangetal.ThispaperdescribesthestructureelucidationofanewIignanglucoside,namedtibeticosideA1...     

Synthesis and Characterization of Liquid Crystal with Lower Temperature of Phase Change of meso-tetra-(4-n-lauroyloxyphenyl)porphyrin

Metalloporphyrincomplexeshavebeenextensivelystudiedinmanyfunctionalchemistrytieldssuchasphoto-eletronicconversionnon-linearoptics,biomimeticstudiesandcatalyticefttcts.TOourknowledge,thefirstliquidcrystallineporphyrinwassynthesizedbyGoodbyelall.In1987,Greggetapreportedthesynthesisandtheliquidcrystallinepropertiesofaseriesofporphyrinoctanolesters.In1987,Greggelal3synthesizedoctakis(0-hydroxyethyl)porphyrin.In1991,tetrakis(4-n-lauroylphenyl)porphyrinwaspreparedbyShimizuetal#.In1994,5.15-disubs…     

Sol-gel derived nanocrystalline and mesoporous barium strontium titanate prepared at room temperature

Perovskite-type barium strontium titanate(BST) thin films and powders with nanocrystalline and mesoporous structure were prepared by a straightforward particulate sol-gel route at room temperature. The prepared sol had a narrow particle size distribution of about 20 nm. X-ray diffraction(XRD) revealed that phase composition and preferable orientation growth of BST depended upon the annealing temperature. Transmission electron microscope(TEM) images showed that the crystallite size of the powders decreased w...     

[Cu(2,2''-bpy)Cl2]和[Cu(1,10-phen)C12]在多金属氧酸盐上的多相化:选择性氧化四氢化萘的新催化剂

Mononuclear Cu(II)bipyridine(1)and phenantroline complexes(2)were synthesized and immobilized by different procedures on H3PW12O40 polyoxometalate(POM).Characterization by XRD and SEM-EDX were performed to assess the preservation of the Keggin structure and stoichiometry of the complex.The immobilized complexes were tested as heterogeneous catalysts for the partial oxidation of tetralin(1,2,3,4-tetrahydronaphthalene)using hydrogen peroxide as oxidant in acetonitrile/water as solvent.[Cu(2,2'-bpy)Cl][H2PW12O...     

晃荡

本文列举了诸多工程领域中的液体共振运动现象,详细探讨了船舱中伴有剧烈流动的晃荡问题.描述了基于理论分析的非线性多模态方法,该方法便于波动稳定性分区、多分支解和物理稳定性的研究.强调了方形舱、垂向圆柱舱以及球形舱内伴有旋转和混沌(不规则波动)的三维流动的重要性.晃荡引起的砰击涉及到各种各样的内流条件,这些条件随液体深度与舱体长度之比而变化.针对棱柱状LNG舱,讨论了许多与流体力学和热力学参数、影响砰击载荷效应的水弹性以及模型实验缩尺比的物理现象.     

Frequency related localisation of harmonic elastic waves in stratified welds

The paper presents a computational model for elastic waves in a structured weld adjacent to the free surface of an elastic solid. The main emphasis is on the interaction of waves with the micro-structure of the weld. Effects of localisation and channeling of waves are addressed. A model of a grain structure within the weld is also considered.