殷钢中零热胀系数的微观机制

18 97年 ,瑞士物理学家Ｃ .Ｅ .Ｇｕｉｌａｕｍｅ发现了一种奇妙的合金———在室温附近的一个很宽的温度范围内 ,合金的热膨胀系数几乎等于零 .这种合金的组成是 6 5%Ｆｅ和 35%Ｎｉ;呈面心立方结构 ,它的中文名字叫殷钢 ,英文名字是ｉｎｖａｒ,意思是体积不变(ｉｎｖａｒｉａｂｌｅ) .与ｉｎｖａｒ类似 ,Ｇｕｉｌａｕｍｅ还发展了所谓ｅｌｉｎｖａｒ合金 ,加热时合金的弹性 (ｅｌａｓｔｉｃｉｔｙ)不变 ,因而被用于制造钟表游丝 .192 0年 ,Ｇｕｉｌａｕｍｅ因上述发现被授予诺贝尔物理奖 .今天 ,殷钢最重要的应用是 :用来制造彩色电视机显…     

Durable antimicrobial cotton fabric fabricated by carboxymethyl chitosan and quaternary ammonium salts

Cellulose - In this article, carboxymethyl chitosan (CMC) and (3-carboxypropyl) trimethylammonium chloride (CPTC) were used as raw materials to prepare an antibacterial cotton fabric with excellent...     

Oxidative dehydrogenation of ethane to ethene over a superbase supported LiCl system

<正>LiCl-promoted superbase catalysts were found to be stable and highly selective to ethene for oxidative dehydrogenation of ethane,giving 84%ethane conversion and 74%ethene yield at 923 K.Results indicated that the stronger the basicity of LiC1-based catalysts,the better the catalytic performance.     

On some Diophantine fourier series

We continue our study on arithmetical Fourier series by considering two Fourier series which are related to Diophantine analysis. The first one was studied by Hardy and Littlewood in connection with the classification of numbers and the second one was studied by Hartman and Wintner by Lebesgue integration theory.     

Preconcentration and separation of trace Pd(II) and Pt(IV) with silica gel bonded by aminopropyl-benzoylazo-4-(2-pyridyl-azo)-resorcinol

This paper reports a simple and highly selective method for preconcentrating and separating of trace Pd(II) and Pt(IV) with silica gel bonded by aminopropyl-benzoylazo-4-(2-pyridy-lazo)-resorcinol (ABPR-SG). ABPR-SG is stable in solution from 6 mol/L HCl to pH 7.0 and in common organic solvents. The maximum adsorptive capacity of Pd(n) on ABPR-SG is 362 μmol/g. After preconcentration and separation by using ABPR-SG column, Pd(II) and Pt(IV) of μg/L level in artificial water samples can be measured reliably by common spedrophotometry. The maximum concentration factors of Pd(II) and Pt(IV) on ABPR-SG column are 143 and 125 respectively. The chromatographic column packed with ABPR-SG can be reused. The method is simple and efficient.     

Copper‐catalyzed asymmetric 1,4‐conjugate addition of dialkylzinc to enones

Asymmetric 1,4‐conjugation addition of dialkylzinc (diethylzinc and dimethylzinc) to cyclic enones, chalcone and nitroalkenes was achieved by a 25 mol% (R)‐6,6′‐Br₂‐BINOL( 1f ), 25 mol% CuSPh and 100 mol% dicyclohexylmethylamin(Cy₂NMe) catalyst system. The Cu(I) catalyst system enables the cyclic enone, chalcone and nitroalkene generality with high enantioselectivity (up to 84% ee) and isolated yield (up to 94%) under mild reaction conditions. Copyright © 2010 John Wiley & Sons, Ltd.     

Stereoselective Synthesis of 2-(4-Hydroxyphenyl)-3-hydroxymethyl-1,4-benzodioxane-6-aldehyde—The Key Intermediate of Sinaiticin

SlflsltlC！fi10，dn8VOflOI！gflsfl．W3SISOhtCdnOffiSlhQltICtiffiIC3VCSsfldhdIflhibltOYy卜388cellactlvltyl．巨histypeofnaturalproductshaveshownvariousbloactlvltyandreceivedconsiderableattentionfromsyntheticchemlstsy．Wewishtoreportastereoselectlvetotalsynthesisofslnaltlclnfromreadilyavailablestartingmaterials（land4）．OursyntheticdesignIsbaseduponconstructionofthesubstitutedbenzouioxanering，to！lowedbyformationof＊theX＊＊flavanonolmoietyFromSchemel，wecansee！natInnilssynthesisofs…