搜索结果: 46-60 共查到“知识库 元素化学”相关记录210条 . 查询时间(1.609 秒)
用离子液前驱体合成高荧光性能的ZnO和CdS纳米材料
离子液 氧化锌 硫化镉
2009/8/27
合成了含Cd和Zn的离子液, 使其提供金属离子, 与Na2S反应制备离子液包裹的半导体纳米材料. X射线衍射和透射电子显微镜分析结果显示: 在Cd离子液与Na2S反应中, 得到的是尺寸在5 ~ 6 nm、离子液包裹CdS纳米晶, 而在Zn的体系中, 最终产物为尺寸在1 μm左右六方盘形貌的ZnO颗粒. 用热力学和结晶动力学详细讨论了造成Cd和Zn体系在反应条件相同时, 产物的形貌和结构差别的原因....
A density functional theory study of oxidation of benzene to phenol by N2O on Fe- and Co-ZSM-5 clusters
DFT benzene oxidation phenol N2O Fe-ZSM-5 Co-ZSM-5
2010/4/8
Density functional theory (DFT) calculations were carried out in the study of oxidation of benzene to phenol by N2O on relaxed [(SiH3)4AlO4M] (where M=Fe, Co) cluster models representing Fe- and Co-ZS...
Ferric Hydrogen Sulfate as an Efficient Heterogeneous Catalyst for Environmentally Friendly Greener Synthesis of 1,8-Dioxo-Octahydroxanthenes
Fe(HSO4)3 dimedone heterogeneous catalyst 1,8-dioxo-octahydroxanthene
2010/4/9
Ferric hydrogen sulfate was used as an environmentally friendly heterogeneous acidic catalyst for the greener, 1-pot, 3-component synthesis of 1,8-dioxo-octahydroxanthene via condensation reactions be...
合成了新的配合物EuL3phen，。采用元素分析，红外光谱，质谱对该配合物的结构进行了表征。该化合物在半导体InGaN芯片发出的近紫外光激发下，发出铕(Ⅲ)离子5D0—7FJ(J=0～4)跃迁特征红光, 最大发射峰位于613 nm, 发光量子效率为13%。配合物寿命为 470 μs，寿命曲线很好地和单指数衰减拟合曲线相吻合。配合物热稳定性达到220 ℃，满足制备LED器件的要求。将配合物EuL3p...
探求元素周期表形成的数学机制及排列形式，推算周期与元素总数。方法 根据现有元素周期表中的编组数据，结合人体骨编组数据，分析、推演、计算。结果 元素的化生演化符合老子“一生二，二生三，三生万物”的论断，由总体1演化成金属与非金属2类，天然元素与人造元素2部分，后由3与5或5与6通过四则运算、阶加等计算机制形成8或11周期18族共144种元素。包括：金属元素120种，非金属元素24种；天然元素90种，...
Synthesis and Characterization of Tetraoxime Ligand, Bis-[(2E,3E,2´E)-3,3´-(1,2-Phenylene-Dinitrilo)dibutan-2-One Dioxime] and Its Dinuclear and Tetranuclear Copper(II)/Nickel(II) Complexes
Tetraoxime dinuclear tetranuclear copper and nickel complexes
2010/4/9
A new tetraoxime, (H4L), was prepared in EtOH by reacting biphenyl-3,3´,4,4´-tetramine with butane-2,3-dione oxime. The tetraoxime ligand was characterized by elemental analyses, H-NMR and...
Bromination of Tetrachlorobenzobarrelene: Polyhalogenated Benzobicyclics
Benzobarrelene bromination Wagner-Meerwein rearrangement polyhalogenides
2010/4/9
The low and high temperature bromination reaction of tetrachlorobenzobarrelene was studied and the possible role of a neighboring group in rearrangements was investigated. New polyhalogenated benzobic...
Silver Ion-Assisted Ring Expansions in Different Solvent Systems
Carbene bicyclic compound ring opening ring expansion vinylic halide
2010/4/9
Several ring expansion products carrying vinylic bromo functionality were synthesized by opening of the geminal dibromobicyclo[n.1.0]alkanes ring. Dibromocarbene was formed from bromoform and potassiu...
6-Ketomethyl Phenanthridine as a New Carrier in the Construction of a Highly Selective Fe(III) Ion-Selective Membrane Electrode
1-(4-Dimethyl aminophenyl)-2-(5H-phenanthridine-6-ylidene)-ethanone Fe(III) ion-selective electrode PVC membrane
2010/4/9
A new Fe3+ ion-selective membrane electrode based on 6-ketomethyl phenanthridine (6-KMPT) and 1-(4-dimethyl aminophenyl)-2-(5H-phenanthridine-6-ylidene)-ethanone, which were incorporated in a plastici...
[In2(HPO3)4]·(NH3CH2CH2NH3)的水热合成与晶体结构
水热合成 晶体结构 乙二胺 亚磷酸铟
2008/12/16
用乙二胺作模板剂在水热条件下合成出一个新的三维开放骨架结构的亚磷酸铟[In2(HPO3)4]·(NH3CH2CH2NH3)(1), 并对其晶体结构进行了测定和表征.
碱金属离子对SrCl2：Eu^2＋发光性能的影响
SrCl2：Eu^2＋ Eu^2＋ 不等价取代 还原
2008/12/12
采用中低热固相法合成SrCl2：Eu^2+，R^+(R=Li，Na，K)荧光体，用XRD，PL，XPS等方法研究了它的结构、荧光性质以及铕的价态，结果表明，SrCl2：Eu^2+，R^+荧光体在262nm或330nm波长的UV光激发下产生强蓝光，发射峰位在405～415nm之间．因为Eu^2+和Sr^2+的离子半径相近，还原生成的Eu^2+占据部分Sr^2+的格位，有利于晶格的稳定，不会导致晶格畸...
用沉淀法合成了掺杂Y^3+,La^3+的CaSO4:Eu^2+稀土发光材料，研究了材料的晶体结构和荧光光谱。根据样品基本上属正交晶系、C2v空间群。Eu离子在CaSO4中的激发峰为基态到4f^65d(Eg),(T2g)激发态的跃近；样品发射主峰位于383nm，属于Eu^2+的^5P7/2→^8S2/7跃迁，说明样品中Eu离子主要以Eu^2+的形式存在。CaSO4:RE(La,Y)本身没有荧光，Y^...
[Eu2(TCM)2(DMSO)6]·2DMSO双核笼状稀土配合物的合成与结构
稀土配合物 双核笼状结构 晶体结构
2008/12/10
报道一个H3TCM配体在较小尺寸的溶剂DMSO中与稀土离子Eu3+通过自组装形成的双核笼状结构, 从中可进一步看出溶剂分子的尺寸对该双核结构的影响.
2-氨基-5-烷基-1,3,4-噻二唑修饰环糊精的制备与表征
1,3,4-噻二唑 环糊精 合成 抗菌活性
2008/12/1
在N2气保护下, 用单-(6-对甲苯磺酰基)-CD(β-CD-6-OTs)和过量的2-氨基-5-烷基-1,3,4-噻二唑在80 ℃反应2 d, 合成了5种新的2-氨基-5-烷基-1,3,4-噻二唑修饰β-环糊精. 化合物的结构用IR, 1H NMR, 13C NMR, UV, MS和元素分析等方法进行了表征. 由于环糊精的屏蔽效应, 在2-氨基-1,3,4-噻二唑修饰β-环糊精的 1H NMR中,...