C-60 trianion-mediated electrocatalysis and amperometric sensing of hydrogen peroxide

Heterogeneous electrocatalytic reduction of hydrogen peroxide (H2O2) by C-60 is reported for the first time. C-60 is embedded in tetra octyl ammonium bromide (TOAB) film and is characterized by scanning electron microscopy and cyclic voltammetry. Electrocatalytic studies show that the trianion of C-60 mediates the electrocatalytic reduction of H2O2 in aqueous solution containing 0.1 M KCl. Application of such film modified electrode as an amperometric sensor for H2O2 determination is also examined.

齐聚苯胺修饰的三联吡啶铁配合物的合成及其光谱和电化学性质

合成了一系列齐聚苯胺修饰的三联吡啶铁配合物,研究了齐聚苯胺链长、不同取代基等对配合物光谱性质和氧化还原性质的影响。结果表明,相对于配合物[Fe(TPY)2]2+(TPY:三联吡啶),供电子齐聚苯胺单元的引入,使得修饰基团与配合物中心核[Fe(TPY)2]2+之间形成了强的D-A体系,导致配合物1MLCT吸收波长显著红移至594 nm,且摩尔吸光系数增加近5倍。配合物同时具有基于金属中心、三联吡啶配体和齐聚苯胺单元的多个氧化还原过程,强拉电子取代基使齐聚苯胺单元氧化还原峰简并且峰电势明显正移,而正丁基取代基对氧化还原峰电势的影响较小。

Cyclic oligomers of phenolphthalein polyarylene ether sulfone (ketone): Preparation through cyclo-depolymerisation of corresponding polymers

Cyclic oligomers of phenolphthalein polyarylene ether sulfone(ketone) were prepared through cyclo-depolymerisation of corresponding polymers using CsF as the catalyst in dipolar aprotic solvent DMAc and DMF, and a family of macrocycles containing from dimer up to at least heptamer were confirmed. by GPC, HPLC and MALDI-TOF-MS. The yields of cyclics get as high as 86.3% and 87.9% respectively.

Polyaniline as marine antifouling and corrosion-prevention agent

Conductive polyaniline was found to have special marine antifouling property. The coating from conducting polyaniline and epoxy resin(or polyurethane) can last 6-9 months in Southern China sea, i.e., less than 10% of the coating surface was fouled during this period. The conducting polyaniline has special synergetic antifouling effect on other antifouling agents like cuprous oxide or 4, 4'-dichlorodiphenyltrichloroethane. The conductivity of the polyaniline was found to be extremely important for its antifouling effect. Moreover, employing aliphatic polyamine as solvent of emeraldine base and curing agent of epoxy resin, a new technique to process corrosion prevention coating containing emeraldine base was developed, therefrom the emeraldine base and epoxy resin was in molecular level blending. This technique was solvent free and extremely effective, i.e., only 1wt% of emeraldine base in the coating can have good corrosion prevention property.

In situ epoxidation of ethylene propylene diene rubber by performic acid

In this paper, epoxidation of ethylene propylene diene rubber by in situ generated performic acid is discussed. The samples have been characterized by infra-red and H-1-nuclear magnetic resonance analyses. Quantitative analysis of the reaction products is made possible by using the methyl deformation band at 1377 cm(-1) as internal standard. The conversion of double bonds increases rapidly within the first 1 h, then gradually, over 2 h, has only a slight increase. The maximum conversion ratio of double bonds is about 70%. The relative content of epoxy groups has a top value at about 7 h. The side reactions are also discussed. (C) 1997 Elsevier Science Ltd.

细胞色素C在单糖修饰金电极上的直接电化学

Hill等发现在4,4′-联吡啶存在时,细胞色素C在金电极上能进行准可逆的电化学反应。在研究细胞色素C的直接电化学过程中,人们又发现一些生物小分子如氨基酸、嘌呤等对细胞色素C的电化学反应有促进作用,但迄今未见有关糖类分子对细胞色素C电化学反应促进作用研究的报道。本文研究了5种单糖对细胞色素C电化学反应的促进作用。

Two anthraquinone compounds from a marine actinomycete isolate M097 isolated from Jiaozhou Bay

Two anthraquinone compounds were isolated from the culture broth of a marine actinomycete isolate M097. The structures were elucidated as Aloesaponarin II and 1,6-dihydroxy-8-hydroxymethyl-anthraquinone by detailed interpretation of their spectra. It is the first time that the latter has ever been reported as a secondary metabolite from a wild-type strain. The results showed that the actinomycete isolate M097 could be a promising material for studying the biosynthetic pathway of polyketides and the production of novel recombinant polyketides.

Effective dielectric response of nonlinear composites with external ac and dc electric field

The perturbation method is developed to investigate the effective nonlinear dielectric response of Kerr composites when the external ac and dc electric field is applied. Under the external ac and dc electric field E-app=E-a(1+sin omegat), the effective coupling nonlinear response can be induced by the cubic nonlinearity of Kerr nonlinear materials at the zero frequency, the finite basic frequency omega, the second and the third harmonics, 2omega and 3omega, and so on. As an example, we have investigated the cylindrical inclusions randomly embedded in a host and derived the formulas of the effective nonlinear dielectric response at harmonics in dilute limit. For a higher concentration of inclusions, we have proposed a nonlinear effective-medium approximation by introducing the general effective nonlinear response. With the relationships between the effective nonlinear response at harmonics and the general effective nonlinear response, we have derived a set of formulas of the effective nonlinear dielectric responses at harmonics for a larger volume fraction. (C) 2004 American Institute of Physics.

牙鲆Paralichthys olivaceus（♀）×夏鲆Paralichthys dentaus（♂）分子遗传学及数量遗传学研究

本论文采用扩增片段长度多态性（AFLP）技术对牙鲆Paralichthys olivaceus群体和夏鲆Paralichthys dentaus 群体进行了种群鉴定和遗传结构分析。共用8 对引物对两个群体（每个群体30 个个体）进行了分析。总共产生了379 个条带，条带大小在60－1000bp。牙鲆与夏鲆的遗传多态性分别为53.83%和22.22%。牙鲆群体的多态位点数显著低于夏鲆群体。牙鲆群体和夏鲆群体种的特异条带分别为27.3% 和 29.61%。两群体平均杂和度分别为0.0701 和 0.1556，香农氏多态指数分别为0.1044 和0.2387。群体内平均遗传距离分别为0.0705 （0.0214 到0.1377）和0.1656 （0.0629 到 0.2338），两群体间的平均遗传距离为0.6328。 AFLP 技术是进行种间群体结构分析的一个很好的分子标记方法，对牙鲆和夏鲆亲本群体进行遗传背景析为今后的杂交育种阐明种间杂交的遗传机理奠定基础。 在本论文中我们采用5×8 因子交配设计建立了牙鲆P. olivaceus（♀）× 夏鲆P. dentaus（♂）杂交家系，对生长相关性状的遗传力进行分析。所有家系都混合养殖在同一养殖池中，40 日龄，在养殖池中随机采集600 个个体，测量体长，体宽，体重等数量性状；然后提取杂交子代DNA 进行家系的鉴定。首先从牙鲆的微卫星中筛选了在牙鲆、夏鲆以及杂交子代扩增多态性较好的10 对微卫星引物（Po1, Po13, Po20, Po35, Po42, Po48, Po56, Po58, Po91, Poli 23TUF）。我们采用了三对引物对600 个个体进行了家系鉴定，共有400 多个体鉴定出自己的亲本，成功率达到80％以上。基于以上结果我们认为微卫星标记可以做为一个有效的标记来代替现实的物理标记，并且可以在子代的早期进行亲本的鉴定。 在养殖过程中，我们对自交和杂交家系生长状况进行了跟踪分析，在181刘清华 牙鲆（♀）×夏鲆（♂）分子遗传学及数量遗传学研究 博士学位论文II日龄之前杂交鲆体长和体重均为未表现出杂种优势，杂种优势率值始终为负值，但是绝对值在逐渐减小。从196 日龄之后杂交鲆杂种优势开始表现出来，并且在196 日龄之后杂种优势率显著的增加。256 日龄体长杂种优势率为14.29%，体重杂种优势率为59.78%, 271 日龄体长杂种优势率达到27.36%，体重杂种优势率为 102.32%。 本研究对杂交鲆在40 日龄的体长，体高、尾柄长、尾柄高，以及全长和体重的遗传力进行了估计，5 个性状的体长半同胞遗传力h2 S 为0.00146－0.719，5个性状的全同胞遗传力h2D 为0.00121－0.632，5 个性状的半同胞和全同胞的平均遗传力h2SD 为0.001335－0.6755。其中全长的遗传力最大。实验结果说明对早期幼鱼进行体长、体重等性状实施选育策略可能会显著影响后期杂交鲆的生长。

长江源区植物区系研究

长江源区位于青海省西南部, 北纬31°35′～ 36°30′,东经89°35′～ 97°55′。本地区共有种子植物62科、321属、1377种。区系特征表现为: 1. 温带成分占96. 81% , 以绝对优势确定了本区系明显的温带性质。2. 世界成分多为衍生, 更兼所含的中国特有属亦多为衍生, 表明本区系的年轻性和衍生的性质。3. 主要植被均属典型的高寒类型, 它们的建群种亦多为典型的高寒植被的特征种。所以, 本区系高寒植被典型, 特征种典型, 高寒区系特色明显。4. 生态环境对本区系特征的塑造表现为高寒生态因子的选择和高山特化的作用强烈, 而在一定程度上湿冷生性质和寒旱生性质的高山特化作用更为明显。长江源区的植物区系是唐古特地区高山区系的代表之一。在中国特有种的分析中, 本区系与横断山和甘肃南部区系的联系最为密切,三者间的共有种最为丰富, 有593种, 占本区中国特有种的 74. 69%。关于唐古特地区的南部界线, 作者认为, 李锡文等(1993) 的“川西北、甘西南、青东南小区”同唐古特地区关系最为密切, 若能在考虑这一因素的前提下来划分似乎更合适, 也更能体现唐古特地区作为一个独立区系的自然界线。

A new species of Saussurea (Asteraceae) from Tibet and its systematic position based on ITS sequence analysis

A new species of Saussurea, S. erecta S. W Liu, J. T Pan A J. Q. Liu sp. nov., is described from Tibet. It resembles S. kingii but may be distinguished by having distinct stems and glabrous achenes. Saussurea kingii was placed in sect. Pseudoeriocoryne of subgen. Eriocoryne; this section was circumscribed by acaulescence and an inflorescence with congested capitula surrounded by a rosette of leaves. The discovery of S. erecta with distinct stems, cauline leaves and corymbose capitula blurred the delimitation of sect. Pseudoeriocoryne and suggested that the section may be polyphyletic. Both the close relationship and the significant difference between S. erecta and S. kingii were confirmed by analyses of nrDNA ITS sequences. The resulting phylogenies based on ITS data further suggest that Saussurea sect. Pseudoeriocoryne, as traditionally defined, does not constitute a monophyletic group. The rapid radiation and speciation of Saussurea in the Qinghai-Tibetan Plateau, as inferred from ITS phylogeny, are discussed. (c) 2005 The Linnean Society of London.

移动机器人人机互助行走监控方法研究及其实际应用

由于行走监控在移动机器人技术中的独特地位和作用，使得其问题解决路线与最终性能极大地影响着构成系统的实用性及用户接受程度．本文通过剖析行走监控同其他模块的内在联系，深入地讨论了研究此问题的必要性和困难所在．最后，结合一个实际应用系统，给出了行之有效的指导思想、实现策略和关键问题解决途径。

Heat capacity enhancement and thermodynamic properties of nanostructured amorphous SiO2

The heat capacity of nanostructured amorphous SiO2 (na-SiO2) has been measured by adiabatic calorimetric method over the temperature range 9-354 K. TG and differential scanning calorimeter (DSC) were also employed to determine the thermal stability. Glass transition temperature (T-g) for the two same grain sizes with different specific surface of naSiO(2) samples and one coarse-grained amorphous SiO2 (ca-SiO2) sample were determined to be 1377, 1397 and 1320 K, respectively. The low temperature experimental results show that there are significant heat capacity (C-P) enhancements among na-SiO2 samples and ca-SiO2. Entropy, enthalpy, Gibbs free energy and Debye temperature (theta (D)) were obtained based on the low temperature heat capacity measurement of na-SiO2. The Cp enhancements of na-SiO2 were discussed in terms of configurational and vibrational entropy. (C) 2001 Elsevier Science B.V. All rights reserved.