K3C60单晶膜的同步辐射光电子谱研究

在C₆₀单晶(111)解理面上制备出厚度约30 nm的K₃C₆₀单晶膜.利用同步辐射光源,在低温下(约150K)测量了样品法向发射的角分辨光电子谱.观察到K₃C₆₀导带和价带明显的色散.导带的光电子谱峰可清晰分辨出4个子峰,这些子峰的最大色散超过0.5eV,并且色散曲线与K₃C₆₀的一维无序晶体结构模型下的能带理论基本吻合,只是子带间隔差异较大.     

Determination and Temperature Dependence of Plateau Modulus for Polymerization of Propylene to Isotactic Polypropylene with Ultra-high Molecular Weight under Catalysis of Ziegler-Natta Catalyst

The viscoelastic behavior of isotactic polypropylene with ultra-high molecular weight (UHPPH) and broad molecular weight distribution(MWD), produced in the presence of Ziegler-Natta catalyst, was investigated by means of oscillatory rheometry at 180 and 200 ℃, whose loss modulus(G") plots at 180 and 200 ℃versus the natural logarithm of angular frequency(ω) present a pronounced maximum at 34.35 and 69.21 rad/s, respectively, and do not show a maximum peak at 0. 01-100 rad/s for Ziegler-Natta catalyzing ethylenepropylene random copolymerization (PPR) with a conventional molecular weight and broad MWD. The fact indicates that the high molecular weight is responsible for a maximum peak of G"(ω) vs. lnω curves for UHPPH. This makes it possible to determine the plateau modulus (G0N) of UHPPH from a certain experimental temperature G"(ω) curve directly. For UHPPH, the G0N determined to be 4. 28×105 and 3. 62×105 Pa at 180and 200 ℃, respectively, decreases with the increase of temperature and is independent of the molecular weight, which directly confirms reputation theoretical prediction that the G0N has no relation to the molecular weight.     

Crystal Structure of Ethyl 4-benzoyl-1a,2,3,4-tetrahydro-3-methyl-1a-(4-methylphenyl)-1H-azirino〔1,2-a〕〔1,5〕 benzodiazepine-1-carboxylate(C_(28)H_(28)N_2O_3)

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Synthesis and Crystal Structure of a Mixed Cu - Cd Bim etallic Com plex ｛〔 Cu Cd(pba)( H_2 O)_3〕·2 H_2 O｝ _n

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苯酚在热氧化法制备的SnO2/Ti 电极上的电氧化研究

A SnO₂/Ti electrode prepared by thermal oxidation was used as the anode for galvanostatic electrolysis in acidic solution containing phenol, the time-dependances of phenol concentration,chemical oxygen demand in solution(COD)and instantaneous current efficiency were determined during electrolysis.The results show that with the SnO₂/Ti anode instead of Pt,the COD significantly decreases at the same charge passage, and average current efficiency of oxidation increases by three times The mechanism for phenol oxidation at two electrodes was discussed.     

单分子结的构筑及分子电导性质的测试

分子电子学已成为21世纪研究的热点. 通过将具有特定功能的分子连接在纳米尺度金属电极之间从而构筑包括分子导线、开关、整流器在内的各种分子尺度电子器件, 这引起了科学家们广泛的研究兴趣. 在分子电子学研究中, 构筑金属/分子/金属(MMM)分子结是研究分子器件中电子传输性质的关键. 尽管已经取得了很大的进展, 目前在纳米尺度下构筑稳定可靠的MMM分子结并测试单个分子的电学性质仍然面临很多挑战. 本文着重对单分子电学性质的测试技术和相关理论研究的最新进展以及存在的挑战做了概述.     

A Quasi-Interpolation Satisfying Quadratic Polynomial Reproduction with Radial Basis Functions

In this paper,a new quasi-interpolation with radial basis functions which satis- fies quadratic polynomial reproduction is constructed on the infinite set of equally spaced data.A new basis function is constructed by making convolution integral with a constructed spline and a given radial basis function.In particular,for twicely differ- entiable function the proposed method provides better approximation and also takes care of derivatives approximation.     

Synthesis and Characterization of Poly(ether imide)s Containing m-Methyl and Phthalazinone Moieties

Aromatic polyimides are distinguished for their excellent mechanical and thermal properties in many engineering fields1. However, aromatic polyimides are normally insoluble in common organic solvents, which restricts their applications in some fields. Many efforts have been taken to improve their solubility. Introducing bulky side groups and non-coplanar structure into polymers bone chains is a good way to obtain the polymers with excellent mechanical and thermal properties2. In this paper…     

An Efficient and Green Procedure for the Preparation of gem-Dicar- boxylates from Aldehydes Catalyzed by Fe_2(SO_4)_3·xH_2O

~~An Efficient and Green Procedure for the Preparation of gem-Dicar- boxylates from Aldehydes Catalyzed by Fe_2(SO_4)_3·xH_2O~~