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YANG Guang Fu ② 《结构化学》1999,(5)
1 INTRODUCTIONItwasreportedthattheheterocycliccompoundscontaining1,2,4triazolo〔1,5a〕pyrimidinyldisplayedpotentialbiologicalactivities〔1,2〕.However,theherbicidalactivityofthe(thio)etherderivativesof1,2,4triazolo〔1,5a〕pyrimidinewasrarelyreported〔… 相似文献
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YUAN Zhi-Qing a Lü Guang-Lie a② WEI Fan-Song b LEI Yong-Quan b a 《结构化学》2004,23(5):520-524
Crystal structures of nonstoichiometric La(Ni, Sn)5 x (x = 0.1~0.4) alloysprepared by different methods were investigated by using powder X-ray diffraction and Rietveldrefinement analysis. Space group of this type of alloys belongs to P6/mmm, in which Sn onlyoccupies the 3g sites. It has been demonstrated that some of the la sites of the nonstoichiometricalloy are replaced by the Ni-Ni dumb-bells which have a strong correlation with the anisotropicthermal parameter B33. The preparation methods have an effect on the number of dumb-bells thatcan substitute the l a sites. It was found that the annealed alloys have more Ni-Ni dumb-bells inthe structure than the rapid solidified and as-cast alloys have while still keep good crystallinity. 相似文献
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有监督主成分回归法在近红外光谱定量分析中的应用研究 总被引:5,自引:0,他引:5
介绍了运用有监督主成分回归法建立近红外光谱定量分析模型的原理和方法.利用该方法先进行近红外光谱定量分析建模的波长信息选择,达到降低光谱数据维数的目的,然后建立数学模型,并用其分析预测集样品.文中以66个小麦样品为实验材料,随机选择其中40个样品建立小麦样品中蛋白质含量的近红外光谱定量分析模型,首先优选出4个波长点:4 632,4 636,5 994,5 997 cm-1,利用这4个波长点处光谱信息建立主成分回归模型预测26个样品的蛋白质含量,其结果与凯氏定氮法分析结果的相关系数为0.991,平均相对误差为1.5%.该方法从大量光谱数据中筛选出最重要的部分波长信息,实现了"少而精"的波长点选择,对建立抗共线性信息干扰的光谱定量分析模型,同时对指导专用近红外分析仪器设计中波长点的选择等方面都有一定的意义. 相似文献
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Two new borate compounds,C4H10N2·B6O8(OH)2 1 and (NH3CH2CH2NH3)B5O8-(OH) 2,have been solvothermally synthesized and structurally characterized by single-crystal X-ray diffraction,IR,elemental analysis and thermal analysis. Compound 1 crystallizes in the monoclinic system,space group P21/c,with a=8.3318(17),b=6.2118(12),c=12.479(3) ,β=108.96(3)o,V=610.8(2) 3,Mr=313.02,Z=2,Dc=1.702 g/cm3,μ=0.150 mm-1,F(000)=320,R =0.0387 and wR =0.0924. Its layered structure is linked by infinite covalently coordinated neutral sheets with 3,20-membered window system,which are built up from alternative B6O8(OH)2 subunits donated by two piperzazine nitrogen donors. 2 crystallizes in monoclinic,space group Cc,with a=6.7207(13),b=11.481(2),c=12.564(3) ,β=95.25(3)o,V=965.4(3) 3,Mr=261.18,Z=4,Dc=1.797 g/cm3,μ= 0.164 mm-1,F(000)=536,R=0.0396 and wR=0.0752. Its oxoborate structure is generated from the sheets of 3,9-membered boron rings bonded diamine molecules through electrostatic and H-bonding interactions to form a two-dimensional layered network. 相似文献
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1 INTRODUCTION A number of hydroxypyrones and hydroxypyridinones are being assessed or considered as orally effective chelators for treatment iron or aluminum overload[1,2]. Almost all present and potential applications involve the tris-ligand complexes of metal(III) cations, as for example in administration of iron(III) complexes for the treatment of anaemia[3], and the appropriate isotopes (e.g. 67Ga, 111In, 90Y) for radiotherapy or the isotopes of gadolinium for magnetic resonance … 相似文献
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PAN Guo-Hua ZHUANG Bo-Tao② WEI Qiang ZHOU Zhang-Feng PENG Sai-Qun WU Ke-Chen CHEN Jiu-Tong 《结构化学》2001,20(5)
1 INTRODUCTION Molybdenum(I) compounds, in particular Mo(I)-SR compounds, are rare amongst numerous Mo compounds. So far, only the following compounds [Mo2(CO)8-n(SR)2(CH_3CN)n] (R = C6H5, CH_2CO2Et, n = 0, 2)[1~5] have been reported in the literature. Recently, we make an effort to develop investigations on Mo(I) compounds on the basis of preparing new Mo(I) compounds by introducing different functional ligands into Mo2(SR)2(CO)8, then determining their structures and measur… 相似文献