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新课程理念倡导学生是学习的主体,但在日常课堂教学中,有些学生的主体地位被过分地放大,教师的主导地位却被人为地弱化.在学生学习的过程中,为了更好地发挥教师作为组织者、引导者、合作者的作用,需要适时、适度的介入.笔者阐述搭桥、阻止、追问和点拨的有效介入策略. 相似文献
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合成了[La(Phen)2(NO3)2(H2O)2]ClO4·2Phen·H2O(1,化学式为C48H38ClN10O13La,Mr=1137.24,Phen=邻菲咯啉),经X-射线单晶衍射测定其晶体结构属于三斜晶系,Pī空间群,a=11.250(4),b=13.364(4),c=16.327(5)(。A),α=103.042(6),β=90.327(6),γ=99.567(6)°,V =2355.8(12)(。A)3,Z = 2,Dc =1.603g·cm-3,F(000)=1148,μ=1.042mm-1,R=0.0569,wR= 0.1064.1由 [La(Phen)2(NO3)2(H2O)2]+ 阳离子,ClO-4阴离子,两个共结晶的Phen分子和1个H2O分子构成.内界的中心金属La(III)离子为十配位的变形的双帽四方反棱柱体,其配位环境分别被6个来自两个双齿配位硝基和两个H2O分子的氧原子和4个来自两个Phen配体的氮原子所包围,形成单核+1价阳离子,外界有1个水分子,1个ClO-4阴离子和两个Phen分子构成.整个分子通过分子间氢键形成3D网络结构. 相似文献
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IntroductionDuringthepastdecades ,thedevelopmentoftheco ordinationchemistryofmolybdenum(VI)focusedonmet al oxygenclusterscharacterizedbyfascinatingstructural,electrochemical,catalytic ,magnetic ,medicinal,andphotophysicalproperties ,1whichareoffundamentaland… 相似文献
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二维纳米空洞方格:诺氟沙星锰(Ⅱ)配合物 总被引:2,自引:0,他引:2
The reactions of norfloxacin (H-Norf) with Mn(ClO4)2·6H2O and Mn(OH)2 yield Mn(H-Norf)(ClO4)2·2H2O (1) and [Mn(Norf)2·4H2O]n (2) , respectively. 1 is monomeric while 2 has a novel 2D neutral square grid with an antibacterial drug as building block. Crystal data for 1: triclinic, space group P1 (No.2), a=9.0939(3), b=9.4395(3), c=12.7182(3)?, α=111.447(2), β=90.340(2), γ=112.357(1)°, V=926.34(5)?3, Z=1, ρcacl=1.664g·cm-3. MoKα radiation (λ=0.71073?), T=293(2)K, μ=0.595mm-1, R1=0.0692, wR2=0.1482 for 2320 observed reflections from 4390 independent reflections, GOF=0.940; Crystal data for 2: Monoclinic, P21/c, a=5.7530(12), b=21.865(4), c=13.343(3)?, β=98.25(3)°, V=1661.1(6)?3, Z=2, ρcacl=1.527g·cm-3, T=293(2)K, μ=0.477mm-1, R1=0.0531, wR2=0.1552 for 2070 observed reflections from 2870 independent reflections, GOF=1.384. CCDC: 140819; 151063. 相似文献
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0IntroductionAlthoughtheself-assemblyofchiralsupramolec-ularentitiesiscommoninvivo,itremainsdifficulttorationalizedesignandpreparationofchiralartificialself-assemblingsystems犤1犦.Inrecentyears,chiralmet-al-organicsolidshaveattractedmuchattentionandhavebeenofintensecurrentinterestsduetothepo-tentialapplicationsinawidevarietyoffields犤2~4犦.Thechoiceofchiralaminoacidaseffectivemeanstoobtainhomochiralstructureshaveemergedmanyyears.Morerecently,Chinetal.reportedarationallydesignedaminoacidmetal… 相似文献
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由Co(C lO4)2.6H2O和Sch iff碱吡啶-4-甲醛缩氨基脲反应合成了标题化合物[Co(H4FoPyS)2(H2O)4](C lO4)2.2H2O(1,H4FoPyS为Sch iff碱吡啶-4-甲醛缩氨基脲),其结构经IR,单晶X-射线衍射和元素分析表征。1属三斜晶系,空间群P,īa=6.9015(13),b=10.2030(19),c=11.136(2),α=104.960(3)°,β=90.090(3)°,γ=108.177(4),V=716.9(2)3,Dc=1.613 mg.m-3,Z=1,Mr=696.29,μ=0.868 mm-1和F(000)=359,最终偏差因子分别为R1=0.0857和wR2=0.2361。在1的晶体结构中,Co(Ⅱ)是六配位的稍变形八面体构型,其中2个吡啶氮原子和2个配位水分子占据赤道平面,另外2个配位水分子处于轴向位置。配合物分子通过氢键(N-H┈O和O-H┈O)相连,形成三维超分子网状结构。 相似文献