142 resultados para 324.9861


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In the present study, platinum nanoparticles modified with Prussian blue (PB) have been synthesized by a heterogeneous catalytic reaction. Transmission electronic microscopy (TEM) confirmed the deposition of nanoclusters around the Surfaces of platinum particles, and spectroscopic studies verified that the molecular composition of the nanoclusters was dominantly PB and a minority of platinum ferricyanide. Thus, it was shown that the platinum particles behaved not only as catalysts for the growth of PB, but also as a reactant to generate a PB analogue complex.

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合成了一种新型的含肼五元环二胺单体3,3′-双(N-氨基酞酰亚胺)硫醚(BAPIT),并用1HNMR、IR测试技术确认其结构。采用传统的一步法用对氯酚做溶剂,与二酐4,4′-HQDPA或BPADA聚合得到了2种聚合物,在极性非质子溶剂和酚类溶剂中室温下有很好的溶解性。聚合物4,4′-HQDPA/BAPIT和聚合物BPADA/BAPIT的玻璃化转变温度分别为324和280℃,热失重分析表明,质量损失5%的温度分别为486和466℃。

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Based on the electrostatic attraction Keggin-type polyoxometalate H4SiW12O40 (SiW12) and small molecule 4-aminobenzo-15-crown-5 ether (4-AB15C5) were alternately deposited on poly (allylamine hydrochloride) (PAH)-derived indium tin oxide (ITO) substrate through a layer-by-layer (LBL) self-assembly, forming a supramolecular multilayer film (film-A). SiW12 was also deposited on a glassy carbon electrode (GCE) derived by 4-AB15C5 via covalent bonding in 0.1 M NaCl aqueous solution and formed a composite monolayer film (film-B). UV-vis absorption spectroscopy, X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared (FTIR) spectroscopy measurements demonstrated that the interactions between SiW12 and 4-AB15C5 in both two film electrodes were the same and caused by the bridging action of oxonium ions. But, the nanostructure in the two film electrodes was different. 4-AB15C5 in film-A was oriented horizontally to ITO substrate, however, that in film-B was oriented vertically to GCE. Namely film-A corresponded to a layer structure, and film-B corresponded to an intercalation structure.

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A bulk alloy which consists of the single icosahedral quasicrystalline phase (I-phase) in Ti45Zr35Ni17CU3 alloy has been fabricated by mechanical alloying and subsequent pulse discharge sintering technique. Crystallographic structure analyses show that the bulk alloy is an I-phase. The transport properties of the bulk alloy are examined, and the results show that the room-temperature thermal conductivity is 5.347 W K-(1) m(-1), and the electrical conductivity decreases with increasing the temperature from 300 to 450K. The Seebeck coefficient is negative at the temperature range from 300 to 360K, and changes to positive from 370 to 450K. Hall effect measurements indicate the bulk I-phase alloy has a high carrier concentration. The specific heat capacity increases when the temperature increases from 280 to 324 K.

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A solid catalyst manganese pyrophosphate based on non-sieves to oxidize benzene to phenol with oxidant hydrogen peroxide has shown good conversion with good selectivity in CH3CN at 65 degrees C investigating water contact angle data of three manganese salts, it is found manganese pyrophosphate has certain repulsive water character. It is further to be confirmed by benzene and phenol adsorption experiments onto catalyst surface by GC. With benzene/H2O2 ratio of 1, the benzene conversion of 13.8% with phenol selectivity of 85.0% was achieved. It is noteworthy that no any products are obtained using manganese pyrophosphate as catalyst in the oxidation of phenol in CH3CN solvent.

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A new side chain liquid crystalline poly[4-(methacryloxy)hexanoloxy-4'-benzyloxy biphenyl] was synthesized. The phase behavior of the monomer and homopolymer was studied. The monomer shows a smectic B phase, while the homopolymer shows a nematic phase. The nonmesogenic nonlinear optical group was introduced to synthesize a series of side chain liquid crystalline copolymers which also show a nematic phase. Owing to the liquid crystallinity of the copolymer has been the orientational stability improved, down the relax of the orientation slowed and the nonlinear optical properties enhanced.

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讨论了系统设计和系统评价。首先,根据ICP-AES中有关信息在计算机中的流动、 转换、储存和处理情况设计了计算机流程图,然后根据数据库规范化的要求对数据库的概念 结构、逻辑结构和物理结构的设计作了讨论。该数据库包括了28000余条ICP发射谱线的有 关数据。运行结果表明,该系统设计合理,信息量大,且具有方便、实用的用户界面。

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A series of vinylidene dichloride (VDC) copolymers with methyl acrylate (MA) as comonomer (3-12wt%), was prepared by free-radical suspension copolymerization. The permeability coefficients of the copolymers to oxygen and carbon dioxide were measured at 1.0 MPa and at 30 degrees C, and those to water vapor were measured at 30 degrees C and 100% relative humidity. All the VDC/MA copolymers studied are semicrystalline. As the MA content increases, the permeability coefficients of the copolymers to oxygen, carbon dioxide, and water vapor are progressively increased, caused by decrease in crystalline fraction and increase in free volume of VDC/MA copolymers.

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用核磁共振(NMR)方法研究了稀土离子及其配合物与二棕榈酰磷脂酰胆碱(DPPC)和鞘磷脂(SPM)脂质体的相互作用.磷脂极性头平行于膜平面.稀土离子与磷脂极性头P—O键键合,与经典模型不同,键合后极性基团仍平行于膜平面,而不是垂直于膜平面.稳定的稀土配合物对磷脂脂双层结构影响很小.将稀土离子引入磷脂脂质体和小分子配体的混合物中,稀土首先与小分子配体配位.

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In this paper, based on the consideration of covalent behavior of adjacent ions in crystals, a calculation formula of lattice energy was proposed. In which, the concept of ionic effective valence and the empirical formula covalent energy were introduced,

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The composition and structures of Li-Ti-La mixed oxides as well as their catalytic activity for methane oxidative coupling have been studied by means of XRD XPS, IR, SEM and so on. The results indicate that by changing x value in Li-La1-xTixO2 oxides phas

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我们在考虑了晶体中近邻正、负离子的共价行为的基础上,提出了晶体点阵能的计算公式,并引进了离子有效价态的概念和共价能计算的经验表达式,把二元离子晶体点阵能的计算推广到一般极性共价晶体和其他复杂晶体,计算结果与实验结果符合得很好.

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研究了Ti-La-Li三元氧化物的组成、结构及其对甲烷氧化偶联反应的催化性能;用XRD、IR、XPS和SEM等方法对催化剂进行表征,结果表明:在Li-TixLa1-xO2系列催化剂中,随x值的不同,可生成LaTi1-yLiyO3-λ、、Li2TiO3、La0.66TiO2.993、La2O3和Li1.33Ti1.66O4几种物相,其中,钙钛矿到三元复合氧化物LaTi1-yLiyO3-λ是甲烷氧化偶联反应的主要活性相,活性位Li+-O--Ti3+的形成是活性提高的主要原因.Li2TiO3和La0.66TiO2.993是深度氧化活性相,而Li1.33Ti1.66O4既无偶联活性,也无深度氧化活性.

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The electrochemical reduction of bilirubin (BR) in dimethyl formamide (DMF) is discussed in detail. The kinetic study of the electroreduction process of BR results in values of 7.94 x 10(-6) cm2/s for the diffusion coefficient and about 10(-3) cm/s for the standard heterogeneous electrode reaction rate constant. Thin-layer spectroelectrochemical investigations of BR exhibit a blue shift and a red shift at E(pc) = -0.6 V and E(pc) = -0.85 V respectively. They also give values of E0' = -1.55 V and n = 1 for the reduction process, and E0' = -1.35 V and n = 1 for the oxidation process. It was found experimentally that as the potential changes from negative to positive, the sequential color changes are similar to those of some of the color components in visible light. A mechanism for BR electroreduction in DMF has been proposed.