简介:本文提出一个新的预条件子,用共轭梯度法求解对称正定的Teoplitz型线性方程组.该预处理子构造简单,易于实施快速傅里叶变换.理论和数值实验显示,我们的预处理子与T.Chan预处理子收敛性相近.
简介:[1]BASFUSP4479906[2]BASFBP1443541[3]BASFDE3618265[4]WangL.,WuZ.,ChinaLeather,26(8),11,(1997)[5]YuanL.,DinY.,ChineseChemistryBulletin,(2),19(1988)[6]KurokiH.,ChemistryofDyeingTheory(ChineseTranslation),TextileIndustryPress,Beijing,89(1982)[7]WangS.,LiP.,WuZ.DyestuffIndustry(Chinese),34(4),1,(1997)[8]Tian,Y.,Wu,Z.,Wang,G.,Zhang,S.J.ChineseChem.Eng.,46,156(1995)[9]Tian,Y.,Wang,G.,Wu,Z.,J.ChineseChem.Eng.,47,75(1996)[10]Lycka,A.,DyesandPigment,32,11(1996)[11]Griffith,J.,ColourandConstitutionofOrganicMolecules,AcademicPress,London,191(1976)
简介:研究了一类奇摄动2m阶椭圆型方程解的多重边层现象.利用比较定理得到解的一致有效的渐近展开式.
简介:Dibromobiphenylreactedwithcynomethylanioninammoniaunderirradiationtoformnucleophilicbis-substitutedproductinhighyieldwithoutsubstantialmonosubstitutedproduct.Quantumyieldsfortheformationsofbis-andmonosubstitutedproductswerefoundtobe85.6and2.3×10-6respectively,whilethecorrespondingpseudo-first-orderrateswere6.9×10-3and5.2×10-10mol.L-1.S-1.Blockupthepossibleelectrontransferof4-brome-4’-cyanomethylbiphenylylradicalanionto4-cyanometbyl-biphenylylradicalandbromineion.
简介:(满分100分,90分钟完成)(/1)基础知识达标检测一、选择题(每小题4分,共40分)1.(,『1+I)x?+r,“一2+,『ii=0是关于r的一元二次方程,邶幺m的值是().({)r,j>一1(B),n>1(C)口‘≠一1(D),H≠02.方程x::x的根是().(1)()(B)l(c)2(D)0或13F列方程中,没有实数根的是().(4)!Y:一7x=0(B)5J!一7J+5=0t、C)!r?+3r一4=0(D)16,+9y=244.,f、等式Ⅲf。。’‘)’0的整数僻的个数足().L2x<5l{)1个(B)!个((j)3个(D)4个5.一啦!