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31.
1 INTRODUCTION During the search of molecule-based materials with interesting properties such as catalysis, cla- thration etc., much attention has been focused on the synthesis of one-, two- and three-dimensional extended solids involving cadmium[1], as its d10 configuration permits a wide variety of geometries and coordination numbers. Rigid bridged ligands such as carboxylate groups are frequently used to construct these materials. Therefore, the coordi- nation chemistry of Cd(Ⅱ) ca…  相似文献   
32.
One- or quasi one-dimensional zinc oxide nanostructures possess plenty of morphologies. Only by controlling the gas flow rates, and partial pressures of argon, oxygen and zinc vapor, can various types of high-quality ZnO nanomaterials (such as wires, belts, arrays, saws or combs, tetraleg rods, nails, and pins) be synthesized through pure zinc powder evaporation without a catalyst at the temperature range of 600–700°C. In this study, deposited nanostructures were characterized by means of scanning electron microscopy, X-ray diffraction and high-resolution transmission electron microscopy. The authors propose and discuss the growth mechanisms of various ZnO. In addition, properties of room temperature photoluminescence and field emission of several typical ZnO nanostructures are measured and investigated.  相似文献   
33.
In this paper, we fabricated a p-PVK/n-ZnO nanorods (NRs)/p-MEH-PPV dual heterojunctions white light-emitting diode. Relative to previously reported p–n heterojunction structure including ZnO NRs and polymer, the device exhibits a low turn-on voltage of 7 V. An obviously broad electroluminescence emission band, originated from the overlap of PVK emission and ZnO defects emissions, was observed extending from 360 up to 700 nm. The influence of the two introduced p-type polymer layers on the device characteristic is discussed. With its hole conductivity, the p-PVK layer cannot only improve the holes tunnel into ZnO NRs layer, but also lower the barrier between ITO and the valance band of ZnO NRs. On the other hand, p-MEH-PPV could be regarded as block layer for the injection of electrons from the Al electrode. Both of two p-type polymers dramatically improve the injection balance of carriers, leading to a low turn-on voltage. Meanwhile, the carrier transport mechanism of the device under different forward bias region was discussed on the basis of current–voltage curve.  相似文献   
34.
The liquid-crystal assembly of semiflexible-coil diblock copolymers with coil or semiflexible homopolymers is studied by dissipative particle dynamics simulation. Phase diagrams of the blends and orientation ordering parameters among semiflexible blocks are constructed as a function of chain stiffness and homopolymer volume fraction. For semiflexible-coil/coil blends with varying stiffness of semiflexible blocks, we display the rich phase behaviors of the system transited from coil-coil/coil to rod-coil/coil blends. The disorder-lamellae or lamellae-liquid crystalline transition and “dry brush” phenomenon induced by coil homopolymers are observed. For semiflexible-coil/semiflexible blends, adding semiflexible homopolymers also leads to a disorder-order transition and even a transition between monolayer and bilayer smectic-A phase. The results demonstrate that blending homopolymers into semiflexible copolymers can induce liquid-crystal assembly and even improve the orientation ordering of semiflexible blocks effectively.  相似文献   
35.
One flexible, discrete coordination cage [Cu(2)(3-BPFA)(4)(H(2)O)(2)](ClO(4))(4).4CH(3)OH (), and two cation-clusters with micro(2)-Cl bridging [Ni(2)(micro-Cl)(3-BPFA)(4)(H(2)O)(2)](ClO(4))(3) () and [Co(2)(micro-Cl)(3-BPFA)(4)(H(2)O)(2)](ClO(4))(4).4CH(3)OH (), containing the ferrocenyl functionality were prepared via coordination-driven self-assembly and Cl-anion template from Cu(II), Ni(II) and Co(II) salts and a flexible two-arm molecule 1,1-bis[(3-pyridylamino)carbonyl]ferrocene (3-BPFA).  相似文献   
36.
利用Au纳米粒子与三聚氰胺相互作用产生的颜色变化来快速评估牛奶中三聚氰胺的含量,采用透射电子显微镜表征Au纳米粒子与三聚氰胺作用前后的形貌变化,通过用紫外-可见吸收光谱数据绘制标准工作曲线来定量测定牛奶中三聚氰胺的含量。该实验贴近生活,学以致用,同时也有助于学生掌握无机化学和分析化学基本操作,对增强学生分析解决问题的能力,提升学生的科研素养也有帮助。  相似文献   
37.
皖南尖吻蝮蛇蛇毒经分离和纯化得到出血毒素Ⅲ(AaH Ⅲ),质谱测定分子量为23,284.4±0.1。实验表明,Trp残基较大程度位于AaH Ⅲ分子的疏水区。十二烷基磺酸钠(SDS)和盐酸胍的加入使AaH Ⅲ的分子构象发生变化,导致分子内色氨酸(Trp)残基的荧光淬灭。盐酸胍的加入使Trp残基的荧光发射峰位明显红移,表明位于AaH Ⅲ分子较疏水环境的Trp残基相对外露。我们还就酸度、EDTA和金属离子对AaH Ⅲ分子内Trp残基荧光光谱的影响进行了研究和讨论。  相似文献   
38.
在 2 5± 0 .1℃ ,I(KNO3) =0 .1 0 mol/ L ,p H=6 .5~ 9(5 0 mmol/ L缓冲溶液 )条件下 ,用分光光度法测定了含醇羟基和酚羟基链型氮氧杂配体 N,N -二 -(2 -羟乙基 ) -乙二胺 (L1)和 N-(2 -羟基苄基 ) -3-氨基 -1 -丙醇 (HL2 )的 Cu( )配合物及 N -(2 -羟乙基 ) -N -(2 -羟基苄基 ) -乙二胺 (HL3)和 N -(2 -羟乙基 ) -二乙三胺(L4 )的 Zn( )配合物催化对硝基苯酚乙酸酯 (NA)水解动力学 ,得到了 NA酯催化水解二级反应速率常数k C.结果表明 ,在中性 p H值附近生成的配位烷氧负离子 Cu( )…… - OR和 Zn( )…… - OR均为很好的亲核试剂 .配合物对 NA酯水解有亲核试剂进攻和金属离子作为 L ewis酸活化底物的双重催化作用 ,k C 值可分别达到 6 .72× 1 0 - 2 ,0 .1 2 6 ,4.5 5× 1 0 - 2 和 7.6 6× 1 0 - 2 mol- 1·L· s- 1.  相似文献   
39.
皖南尖吻蝮蛇毒抗凝血因子Ⅰ(ACFⅠ)不具有酶的活性,通过与活化凝血因子X(FXa)结合成1l的复合物来延长凝血时间。用高效液相色谱分析方法,发现ACFⅠ与FXa的结合反应依赖于Ca  相似文献   
40.
Recently, some schemes on how to realize quantum NOT gate have been reported. In this paper, we theoretically propose a new scheme by means of quantum theory. Here we use a quantum coin as a quantum NOT gate and its logic function is realized by the quantum game theory. In our schemes, classical noise does not disturb the realization of quantum NOT gate.  相似文献   
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