高载酶量酶/酶免疫电极的制备及其电化学机理研究

本文利用扫描电镜和电化学方法确定了最佳镀铂电位,并进一步研究了酶电极和酶免疫电极在基体电极镀铂和未镀铂条件下的米氏常数、电化学反应速率常数和反应速度控制步骤。比较分析了生物电极的最佳实验条件。     

电位控制辣根过氧化酶在金电极上的组装

以辣根过氧化酶(HRP)为模型蛋白质, 研究了蛋白分子的电位控制组装. 采用氨基乙硫醇(AET)在金电极上自组装单分子层(SAMs), 通过改变溶液的酸碱度调节HRP所带的电荷, 利用控制电位方法在SAMs上组装HRP. 借助于酶与底物作用后光密度(OD)的变化研究了不同体系中HRP组装量随控制电位变化的规律, 并用X射线光电子能谱(XPS)和原子力显微镜(AFM)等手段表征了电位控制HRP修饰电极. 结果表明, 控制电位不会改变HRP的活性, 酶-底物作用后显色反应的光密度高低可评价组装HRP分子的相对含量. 在恒电位控制模式下, 流经电极的总电荷接近零时HRP的组装量较多. 该研究将对生物分子的控制组装和生物体内带电器件的设计具有较重要的意义, 并为生物纳米器件的研制提供技术基础.     

LiFePO4电极放电曲线的阻抗模拟

建立了磷酸铁锂(LiFePO4)电极材料放电曲线的阻抗模型.将不同倍率放电的电位分为欧姆电位降、电荷转移电位降与扩散阻抗电位降三部分,以电极交流阻抗谱图结合理论分析,推导出不同倍率电极电位的表达式.模拟结果显示,拟合值与实验值吻合较好.     

聚吡咯为基质的脲酶传感器生物电化学响应

用电化学方法在吡咯（Ｐｙ）聚合的同时,将脲酶掺杂进聚吡咯膜（ＰＰｙ）中形成以聚吡咯为基质的脲酶电极．将脲酶电极与ＣＯ２气敏电极结合,组成对脲有电位响应的脲酶生物传感器．测试了传感器对脲的生物电化学响应．研究了聚合条件对酶活性的影响,并测定了掺杂于聚吡咯中的脲酶的活化能等动力学参数．在５０×１０－５～１．０×１０－２ｍｏｌ／Ｌ的浓度范围内,传感器响应的电极电位与脲浓度的对数成正比．     

Nafion 膜固定的新亚甲基蓝为介体生物传感器

以Nafion膜固定的新亚甲基蓝为辣根过氧化物酶和玻碳电极间的电子传递介体,制成电流型单酶过氧化氢生物传感器和双酶葡萄糖生物传感器。探讨了工作电位、pH值、温度和干扰物质等对生物传感器的影响。     

辣根过氧化物酶／聚邻苯二胺膜电极的制备与性能研究

辣根过氧化物酶（ＨＲＰ）／聚邻苯二胺（ＰＰＤ）膜电极由ｐＨ７．０磷酸盐缓冲溶液介质中邻苯二胺在玻碳电极上的电聚合而制得。讨论了ＨＲＰ电化学固定化的过程。所得酶电极呈现生物催化活性,可在没有电子传递体存在的情况下催化Ｈ＿Ｏ＿２还原。该反应发生在聚邻苯二胺氧化还原的电位区,聚合物参与了酶的电子转移过程。分析了旋转ＨＲＰ／ＰＰＤ电极上酶反应的动力学,讨论了动力学常数的影响因素。     

聚合物膜离子选择性电极传感新方法研究进展

传统的离子选择性电极属于电位型传感器,其检测原理基于电极敏感膜的电位响应与分析物离子的活度关系符合能斯特方程.近年来,以聚合物膜为敏感元件的离子选择性电极蓬勃发展,其换能方式已经从传统的零电流电位检测法发展到计时电位法、库仑法、安培法、离子迁移伏安法、光学法等多种传感新方法.这些新型信号输出方式的采用,提高了聚合物膜离子选择性电极的检测性能、扩大了电极的应用范围.本文综述了近年来发展的聚合物膜离子选择性电极传感新方法,重点介绍了各类分析信号的输出原理与应用,并对该领域未来的发展做出了展望.     

Pt/碳纳米管电极的电化学稳定性

 研究了Pt/CNT(碳纳米管)电极在动电位和恒电位两种情况下的电化学稳定性. 在动电位条件(0.05～1.2 V vs RHE(可逆氢电极)循环伏安940次, 60 h)下, Pt/CNT电极的电化学表面积下降18.8%; 在恒电位条件(1.2 V vs RHE, 60 h)下, Pt/CNT电极的电化学表面积仅下降5.2%. 这表明Pt/CNT电极在动电位条件下性能衰减得更迅速. X射线光电子能谱分析表明,恒电位条件下载体碳纳米管被氧化的程度较大. X射线衍射分析计算表明,动电位和恒电位氧化后, Pt颗粒的平均粒径从3.8 nm分别增大到4.9和3.9 nm. Pt颗粒的长大可能是Pt/CNT电极性能衰减的主要原因之一,而载体的氧化不是Pt/CNT电极性能衰减的主要原因.     

胞嘧啶吸附在粗糙金电极上的表面增强拉曼光谱

应用电化学伏安法和表面增强拉曼光谱(SERS)研究在-1.0 V~0 V电位区间内胞嘧啶于粗糙金电极表面的吸附行为.结果表明,在本实验的电位区间,胞嘧啶是以其N3位垂直吸附在粗糙金电极表面的.在负电位区间环呼吸振动模的强度出现极大值,与其它振动模强度相比,作者认为电磁场的增强和电荷转移均使该谱峰的拉曼信号增强.胞嘧啶的环呼吸振动频率随着电位负移而红移,这意味着它与金电极的成键作用减弱.同时也表明SERS谱可用于研究生物分子在金属电极表面的吸附行为.     

镧系元素在高温下的标准电极电位的计算及其应用

一、前言作者曾论述过在常温水溶液中镧系元素的标准电极电位及其应用,而镧系元素在高温下的标准电极电位数据迄今未见报道。镧系元素在高温下的标准电极电位不易实验测得,故本文尝试通过理论计算的方法求得,即用Cobble提出的离子熵对应原理算出了镧系元素在60℃、100℃、150℃、200℃、250℃、300℃时的标准电极电位,作者还根据计算结果分析了数据的变化规律。     

Mechanisms of solute orientational order in nematic liquid crystals

The order parameters of a number of different solutes dissolved in a number of different nematic liquid-crystal solvents are measured and compared. It is shown that the order parameters can all be rationalized with the ansatz that there exist two independent ordering mechanisms operating in the liquid crystals employed. With this ansatz it is possible to fit the experimental order parameters to better than 5%. This opens the possibility of the accurate prediction of order parameters in ordered liquids.     

氢键碱度的神经网络法计算

氢键在生命科学和化学等领域均起着十分重要的作用.化合物可以通过提供质子和接受质子等两种方式与其它化合物形成分子间氢键,其形成氢键的能力分别称为氢键酸度（hydrogen-bondacidity）和氢键碱度(hydrogen-bondbasicity).可以用正辛醇／水分配系数和环己烷／水分配系数的对数差（ΔlogP）[1]、溶剂化显色参数[2－3]等表示化合物形成氢键的能力,其中应用较多的是Abraham等[4]提出的总氢键酸度（）和总氢键碱度（）.但由于和要通过实验得到,繁琐不便,限制了它们的广泛应用.本文用神经网络法研究了理论计算得到的量子化学参数与之间的相…     

Investigation of optimized experimental parameters including laser wavelength for boron measurement in photovoltaic grade silicon using laser-induced breakdown spectroscopy

The quantification of boron and other impurities in photovoltaic grade silicon was investigated using the LIBS technique with attention to the laser wavelength employed, temporal parameters, and the nature of the ambient gas. The laser wavelength was found to have a moderate effect on the performance of the process, while the type of purge gas and temporal parameters had a strong effect on the signal-to-background ratio (SBR) of the boron spectral emission, which was used to determine the boron concentration in silicon. The three parameters are not independent, meaning that for each different purge gas, different optimal temporal parameters are observed. Electron density was also calculated from Stark broadening of the 390.5 nm silicon emission line in order to better understand the different performances observed when using different gases and gating parameters. Calibration curves were made for boron measurement in silicon using certified standards with different purge gases while using the temporal parameters which had been optimized for that gas. By comparing the calibration curves, it was determined that argon is superior to helium or air for use as the analysis chamber purge gas with an UV laser.     

生物质废弃物的热解研究

生物质能是可再生能源,在生长过程中通过光合作用将碳和能量固定下来,利用生物质能CO2排放很少.为实现可持续能源生产和减少温室气体排放的目的,中国已于2006年1月开始实施《中华人民共和国可再生能源法》.     

大孔树脂型号与规格的规范化探讨

为了探讨现今大孔树脂市场是否规范,通过查找大量文献,找出现今大孔树脂市场上各公司提供的各型号的大孔树脂的性能参数.对比同型号的大孔树脂性能参数是否一致,并通过实验加以验证;以及性能参数相同型号却不同的树脂,通过实验证实是否为同一种型号的树脂.结果发现很多类型的大孔树脂实际性能参数与厂家标示的不一致,不同厂家同一型号的树脂实际性能参数不太相似,部分型号不同性能参数却相似的树脂实际性能参数也相似.现今国内大孔树脂市场比较混乱.     

ANN-MATOPT hybrid algorithm: determination of kinetic and non-kinetic parameters in different reaction mechanisms

In this work we have applied the computational methodology based on Artificial Neural Networks (ANN) to the kinetic study of distinct reaction mechanisms to determine different types of parameters. Moreover, the problems of ambiguity or equivalence are analyzed in the set of parameters to determine in different kinetic systems when these parameters are from different natures. The ambiguity in the set of parameters show the possibility of existence of two possible set of parameter values that fit the experimental data. The deterministic analysis is applied to know beforehand if this problem occurs when rate constants of the different stages of the mechanism and the molar absorption coefficients of the species participating in the reaction are obtained together. Through the deterministic analysis we will analyze if a system is identifiable (unique solution or finite number of solutions) or if it is non-identifiable if it possesses infinite solutions. The determination of parameters of different nature can also present problems due to the different magnitude order, so we must analyze in each case the necessity to apply a second method to improve the values obtained through ANN. If necessary, an optimization mathematical method for improving the values of the parameters obtained with ANN will be used. The complete process, ANN and mathematical optimizations constitutes a hybrid algorithm ANN-MATOPT. The procedure will be applied first for the treatment of synthetic data with the purpose of checking the applicability of the method and after, it will be used in the case of experimental kinetic data.

     

Determination of free surface-energy parameters using a spatial method

A spatial method for determining acid and base parameters of the free surface energy of different solid surfaces using multidimensional approximation based on reduction of the van Oss-Chaudhury-Good equation to the equation of a plane is developed. The obtained results confirm the efficiency of the spatial method for correct determination of free surface-energy parameters for different substances.     

Considerations in the determination of orientational order parameters from X-ray scattering experiments

An assessment of the data processing and analysis methods used to obtain the second- and fourth-rank orientational order parameters of liquid crystals from X-ray scattering experiments has been carried out, using experimental data from four extensively studied alkyl-cyanobiphenyls and calculated data generated from two general types of theoretical orientational distribution function. The application of a background subtraction and two different baseline correction methods to the scattering profiles is assessed, along with three different methods to analyse the processed data. The choice of baseline correction method is shown to have a significant effect: an offset to zero overestimates the order parameters from the experimental and calculated data sets, particularly for lower order parameters arising from broad distributions, whereas an offset to a value estimated from regions of low scattering intensity provides experimental values close to those reported from other experimental techniques. By contrast, the three different analysis methods are shown generally to result in relatively small absolute differences between the order parameters. We outline a straightforward general approach to experimental X-ray scattering data processing and analysis for uniaxial phases that results in order parameters that match well with those reported using other experimental techniques.     

Solvation model in the allylation of 2-mercaptobenzothiazole

The kinetics of the reaction of allyl bromide with 2-mercaptobenzothiazole has been studied in different protic and aprotic solvents conductometrically. The rate data were correlated with solvation parameters using linear multiple regression analysis. From the regression coefficients, which describe the susceptibility towards rate of different solvent parameters, information regarding solvent interactions is obtained and solvation models are proposed. The reaction has also been studied at different temperatures and thermodynamic parameters ∆H^≠, ∆S^≠, ∆G^≠ are computed.     

Thermodynamics and statistical mechanics of multilayer adsorption

The multilayer adsorption models of Brunauer-Emmett-Teller and Guggenheim-Anderson-de Boer are reconsidered. The relationship between the fitting parameters and the physical parameters of the equation is discussed. The preexponential factors of the parameters are shown to be in general far different from unity, contrary to a widespread use. A thermodynamical derivation illuminates the hypothesis on which the multilayer sorption equation is dependent and frees it from too restrictive hypothesis usually taken as necessary for its validity. Equations are derived for the number fraction of sorption sites occupied by different numbers of molecules. The Guggenheim-Anderson-de Boer equation is shown to imply incomplete occupation (jamming) of the first sorption layer at saturation.