214 resultados para 264


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本文报道了细胞色素C在聚乙烯氧化物(PEO)修饰的金电极上的直接电化学行为,发现PEO是细胞色素C电化学反应的促进剂,PEO修饰膜的形态对细胞色素C电化学反应的可逆性有较大的影响.

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A new kind of amphiphilic polyether dendrimer bearing eight alkyl chains at the periphery were synthesized step by step using the convergent method. Their structures were confirmed by FT-IR spectra, H-1 NMR spectra and mass spectra etc. The pi-A isotherms, hysteresis and molecular area-time curves at air water interface were reported. These results showed that they could form stable monolayers at water surface.

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采用聚合物表面涂覆改性的方法,将疏水性聚合物硅橡胶涂覆在聚酰亚胺亲水微孔膜上,制得了具有良好膜蒸馏性能的聚酰亚胺疏水微孔复合膜。研究了涂覆工艺条件对所得聚酰亚胺疏水微孔复合膜的膜蒸馏性能的影响。结果表明,控制适当工艺条件可制得具有高膜蒸馏通量的聚酰亚胺微孔复合膜,其透过系数可达2.17×10-3kg/m2·h·Pa。该改性聚酰亚胺疏水微孔复合膜使用37d后,截留率仍保持在99.5%以上,具有较长使用寿命。

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A new comblike polymer host for polymer electrolyte was synthesized by reacting monomethyl ether of poly(ethylene glycol) with poly(vinyl methyl ether-alt-maleic anhydride) and endcapping the residual carboxylic acid with methanol. Butanone was selected as a solvent for the esterification in order to obtain a completely soluble product. The synthesis process was traced through by LR. Compared with the model compounds, the presumed structure of this comblike polymer has been proved to be valid by C-13 NMR The comb polymer is a white rubbery solid. It can be dissolved in butanone and THF, and manifests good film forming ability.

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Monolayers of liquid-crystalline polyacrylate containing para-nitro azobenzene (HP6) on the water subphase were characterized by the surface pressure (pi)-area per monomer unit (A) isotherm and were successfully transferred onto glass substrates by the vertical lifting method. The monolayer Langmuis-Blodgett (LB) films transferred at different surface pressures were studied by electron diffraction. The thickness of the monolayer LB film was measured by the transmission electron microscopy folding method. The results of the electron diffraction of the monolayer LB films of HP6 showed that a two-dimensional arrangement exists in the transferred films. According to the results of the pi-A isotherm, electron diffraction and the measured thickness of the monolayer LB film, a molecular arrangement model of HP6 on the water subphase was proposed. The ordered monolayer formation of HP6 showed it to be promising as a second-order non-linear optical material.

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Thermal properties of polyaniline (PAn), polytoluidine(POT) and polyanisidine(PAs) were examined by TG and DSC techniques. The weight-uptake of POT at 200-300 degrees C was observed and carefully discussed.

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Electrochemical catalytic reactions of tetraphenylporphinatocobalt were studied in DMF and EtCl2 solutions in the presence of 1,2-dibromoethane and 1, 2-dichloroethane utilizing cyclic voltammetry, thin-layer electrochemistry, in situ UV-visible spectroel

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The complexes of Ln(L-Pro)s(H2O)2(ClO4)3(Ln = Pr, Nd and Er. L-Pro = L-Proline) were synthesized and characterized by elemental analysis, IR. spectra and thermal analysis. The singal crystal Pr2(L-Pro)6(H2O)4(ClO4)6 Was also obtained. The crystal belongs to monoclinic, P2(1), a = 0.9879 (3) nm, b = 2.1883 (4) nm, c = 1.3393 (2)nm, beta = 91.23(2)-degrees, V = 2.895(1) nm3, Z = 2. R = 0.035 for 5032 observed reflections. The coordination polyhedron of Pr(III) ion comprises six oxygen atoms from L-Pro molecules and two water molecules. Each L-Pro molecule coordinates to two Pr(III) ions through its carboxyl group which serves as a bridging bidentate ligand to form onedimensional chain structure.

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本文合成了通式为Ln(L-Pro)_3(H_2O)_2(ClO_4)_3(Ln=Pr、Nd、Er,L-Pro=L-脯氨酸)的固体配合物.元素分析、红外光谱、热分析对配合物进行了表征.培养了镨脯氨酸配合物的单晶,X射线四圓衍射确定了晶体的结构.晶体属于单斜晶系、空间群P2_1,α=0.9879(3),b=2.1883(4),c=1.3393(2)nm,β=91.23(2)°,V=2.895(1)nm~3,Z=2.晶体中每一个镨原子与来自6个L-脯氨酸羧基上的6个氧原子和2个结晶水分子键合,形成了一个八配位的稍有畸变的三角十二面体.每一个L-脯氨酸分子以羧基双齿方式与两个镨离子配位,形成了一个无限长的链状结构.

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自1881年Baeyer首次合成酚酞以来,有关酚酞及酚酞盐结构的研究就一直在不断地进行着。起初只能通过化学模拟反应逐步确定中性酚酞的分子结构。随着现代分析技术

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不久以前,本文的作者之一在试图合成C_9H_7CeCl_3时,得到了非预期产物[Ce(THF)_5Cl_2]~+[Ce(THF)Cl_5]~-(THF=四氢呋喃)的单晶,并测定了其晶体结构,该混价配合物的分子由合Ce(Ⅲ)的配阳离子和含Ce(Ⅳ)的配阴离子组成,它的培养成功为研究铜系元素4f轨道的成键作用及对比镧系离子价态变化对其成键的影响提供了一个极好的机会。本文用INDO方法研究了铈离子混价配合物的电子结构和成键性质。

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钛酸钡(BaTiO_3)晶体在室温附近为四方晶系,空间群为P4mm,具有优良的光折变特性和非线性光学效应,是目前最为理想的非线性光折变材料。BaTiO_3的相图复杂,相变点多,由于六方相在低温下可以亚稳态存在,使得晶体生长必须在1460℃以下进行。本文提出了生长晶体的感应加热三温区温场助熔剂传输溶质方法及装置。这种方法对于那些成晶温度

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我们曾报道利用叔丁基环戊二烯基作配体,可分离得到二叔丁基环戊二烯基轻稀土氯化物,并测定了(t-BuCp)_2PrCl·2THF 的分子结构,与此同时,wayda 报道了叔丁基环戊二烯基中、重稀土氯化物的合成,但未能得到这些配合物的结构。本文用叔丁基环戊二烯钠与无水 YbCl_3以2∶1摩尔比在四氢呋喃中反应,分离得到了中性二叔丁基环戊二烯基氯化镱四氢呋喃配合物,并测定了它的 X 光晶体结构。

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本文研究了甲苯胺(O-,m-,p-)在盐酸水溶中的聚合反应。结果表明,三种甲苯胺的聚合强烈依赖于氧化剂浓度和聚合介质的pH值。用IR、NMR和元素分析等手段表征了可溶聚合物。

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The past decade has seen the genetic engineering of various types of seaweed. To date, genetic transformation studies have been carried out in several seaweeds, including the red seaweeds Porphyra, Gracilaria, Grateloupia, Kappaphyclus and Ceramium and the green seaweed Ulva. A genetic transformation model system has been established in the most commonly cultivated seaweed, the brown seaweed Laminaria japonica (kelp), based on the transfer of technology used in land plant transformation and also by modulating the seaweed life cycle. This model showed the potential for application of transgenic kelp to the production of valuable products and an indoor cultivation system for transgenic kelp was proposed, taking into account necessary factors for bio-safety. In this review, the establishment at use of the kelp transformation model is introduced, highlighting the potential for transforming kelp into a marine bioreactor.