聚丙烯酰胺/聚乙烯醇水凝胶的制备及其在海洋在线监测参比电极中的应用

本文采用正交试验设计制备不同配比的聚丙烯酰胺(PAAm)与聚乙烯醇(PVA)交联的水凝胶,并对其吸水和机械性能进行评价,筛选出适合海洋环境要求的吸水性能优异、机械强度好的最优制备条件。依据该条件制备凝胶,装配成参比电极,测试其电极电位的稳定性。结果表明,该参比电极在模拟海水中有很好的电位稳定性,其稳定后电位的漂移值小于0.1mV,PAAm/PVA水凝胶能作为电解质应用于在线监测的参比电极。     

流动注射-聚中性红膜修饰电极安培法测定痕量亚硝酸根

在由pH6.0磷酸盐缓冲溶液,0.5mol·L-1硝酸钠及1.0×10-4mol.L-1中性红溶液组成的电解质溶液中,用循环伏安法以50mV.s-1扫描速率在玻碳电极上先后在电位-1.3～1.9V及-0.7～0.9V范围内扫描6周及15周,从而制得聚中性红(PNR)膜修饰的玻碳电极。在此修饰电极上,亚硝酸根在电位0.872V(vs.Ag/AgCl)处出现明显的氧化峰。据此并结合流动注射技术提出了安培法测定亚硝酸根的快速方法。方法的工作条件为①采样环体积20μL;②载流0.025mol·L-1磷酸盐缓冲溶液(pH7.0)及0.5mol·L-1氯化钾溶液;③载流流量1.8mL.min-1;④工作电位0.95V(vs.Ag/AgCl)。峰电位值与亚硝酸根浓度在0.8～100μmol.L-1间呈线性关系,其检出限(3σ)为1.0×10-7mol.L-1。以浓度为4.0×10-6mol.L-1亚硝酸根标准溶液平行测定8次,测得其相对标准偏差为3.6%。用此修饰电极连续检测24h,其电流信号保持稳定。此方法应用于分析火腿肠及自来水、湖水等样品,所得回收率在93.0%～112.0%之间。     

高稳定性安培型葡萄糖生物传感器的研究

采用有机改性溶胶凝胶-聚乙烯醇(Ormosil-PVA)包埋葡萄糖氧化酶,制备普鲁士蓝修饰玻碳电极,并基于此制备了安培型葡萄糖生物传感器。以含有FeCl3,K3Fe(CN)6和EDTA的溶液为沉积液,通过循环伏安电沉积法制备了高稳定性的普鲁士蓝修饰电极。考察了扫描电位范围、外加电位、pH和温度等因素对传感器的影响。葡萄糖浓度在20μmol/L~2 mmol/L范围内与响应电流呈线性关系,相关系数R=0.9965,以3倍空白值的标准偏差计算此传感器的检出限为8.1μmol/L。其中,在低浓度(20~100μmol/L)范围内,电流与浓度也呈良好的线性关系(R=0.9938)。     

氢氧化镍薄膜修饰玻碳电极的制备及其对L-赖氨酸氧化的电催化活性

采用恒电位沉积方法将氢氧化镍沉积到玻碳电极表面,得到稳定性高、催化活性好的氢氧化镍薄膜修饰玻碳电极;分析了影响薄膜形成过程的关键因素,确定了最佳薄膜制备方案;与此同时,将薄膜修饰玻碳电极用于生物样品L-赖氨酸的氧化测定,并探讨了其催化作用机理.结果表明,所制备的氢氧化镍薄膜修饰玻碳电极表面发生电化学反应[Ni(OH)2→NiOOH],从而促进电极表面的电子转移,实现对L-赖氨酸的电催化作用.当L-赖氨酸的浓度在1.0×10-4～4.0×10-7 mol/L范围内时,相应氧化峰电流与浓度呈线性关系,检出限达4.0×10-7 mol/L;据此可方便地制备稳定性好且灵敏度高的电流型传感器.     

多壁碳纳米管修饰玻碳电极测定铜离子

以多壁碳纳米管(MWCNTs)修饰玻碳电极为工作电极,采用阳极溶出线性扫描法研究了铜离子的电化学测定方法。探讨了MWCNTs修饰层数、富集电位、富集时间、溶液pH、支持电解质对峰电流的影响。实验表明,铜离子浓度在1.0×10-8~1.0×10-5mol·L-1范围内与峰电流呈良好的线性关系,检测限为2.0×10-9mol·L-1,且该电极具有良好的稳定性和抗干扰能力。     

Nafion修饰Ag/AgCl参比电极的研制及其在pH电化学传感器中的应用

制备了Nafion修饰的Ag/AgCl参比电极,参比电极电位(25℃)为-47.5±1mV,制备的电极有良好的重现性,电极电位不受溶液pH值和Cl-浓度变化的影响,有良好的抗S2-I、-离子干扰能力,且有较好的抗脉冲电流干扰能力。该参比电极适用于间歇式测试场合,可以保证稳定的参比电位;可用于基于W氧化物pH电极的电化学传感器,传感器的内阻为22kΩ,小于玻璃pH电极计内阻(1~10MΩ)。     

识别酪氨酸对映体的分子印迹电化学传感器

掺杂有模板分子L-苯基乳酸的聚吡咯膜通过循环伏安法聚合到碳糊电极表面。在0.1 mol.L-1NaOH溶液中恒电位过氧化处理,将此修饰电极先在D-酪氨酸溶液中富集,在pH2.0的0.1 mol.L-1KCl溶液中溶出。然后将修饰电极再置于0.1 mol.L-1NaOH溶液过氧化处理,以洗脱残留在电极上的D-酪氨酸,按同样方法测试L-酪氨酸。酪氨酸对映体在经过掺杂和过氧化洗脱的聚吡咯电极表面的溶出电位比裸碳糊电极的溶出电位向负方向移动了大约200 mV。在最优化的工作条件下,L-酪氨酸与D-酪氨酸溶出峰电流的比值可以达到2.18。     

适用于钢筋混凝土腐蚀监测的长效MnO2参比电极的研制

以电解法制备的MnO₂粉体为原料,研制了可用于混凝土环境中的固体MnO₂长效参比电极. 在饱和Ca(OH)₂溶液中近一年的监测数据显示,该参比电极具有较好的电位稳定性和抗干扰能力,其电极电位的漂移< 10 mV. EIS和极化曲线测试结果表明,相对于化学法合成的MnO₂电极,电解法制备的MnO₂参比电极具有较小的内阻、较大的交换电流密度、较强的抗极化能力和较低的温度系数（~ 0.68 mV·°C^-1）. 在硬化砂浆中的长期测试表明,该电极在混凝土中的电极电位基本不受Cl^-、有机胺阻锈剂的影响,能作为埋入式参比电极,满足混凝土中Cl^-浓度、pH值和钢筋半电池电位的长期监测的要求,这对于海洋混凝土工程的耐久性监测具有较高的应用价值.     

Ni/Ag2O/RuO2-Pt阴极制备与析氢性能

以三氯化钌和氯铂酸为源物质,用溶胶凝胶法制备Ni/Ag2O/RuO2-Pt复合阴极,研究了不同涂覆液AgNO3浓度和热处理温度对该阴极析氢性能的影响.采用SEM-EDS、XRD和XPS观察阴极的表面形貌、表征其组分,结果表明,Ni/Ag2O/RuO2-Pt复合阴极表面致密,粗糙度大且裂纹少.电化学测量表明,在11 mol.L-1NaOH(90℃)溶液、0.3 A.cm-2电流密度下,Ni/Ag2O/RuO2-Pt复合阴极的析氢电位比纯Ni电极正移484 mV;交换电流密度是纯Ni电极的10倍.该阴极制备工艺简单,析氢活性高,有望降低氯碱工业的能耗.     

壳聚糖/Nafion膜固定氯化血红素制备过氧化氢生物传感器

以壳聚糖/Nafion复合膜为载体在玻碳电极上固定氯化血红素制备过氧化氢生物传感器。研究了血红素电极制备过程中的影响因素及其电化学性质,在1.0 mol/L pH 9.8的NH3-NH4Cl缓冲溶液中,血红素电极对H2O2的催化还原峰电流与H2O2浓度在7.5×10-5~1.45×10-3mol/L范围内成良好的线性关系,检测灵敏度为35.28μA/mM,检测限为3.5×10-5mol/L(S/N=3),同时研究了血红素电极的重现性、稳定性和选择性。     

HEPT类化合物的QSAR研究

为定量结构／活性相关性研究提取了量子化学参数,拓扑指数Am,分子连接性指数^mxt及疏水性常数,同时应用正交变换和最佳变量子集算法（Leaps-and-Bonds)进行了变量压缩和选择,进而实施了多元回归分析,并由此结果进行了HEPT类化合物（1－[(2-hydroxyethoxy)methyl]-6-(phenylthio)-thymine derivatives)的结构／活性关系的理论解释,进行了人工神经网络法对于该类化合物的活性预测,其结构明显好于多元回归法。     

From the Micro- to the Macro-: Managing the Conservation of the Warship,Vasa

Sweden's famous warship, Vasa, sank on her maiden voyage in August 1628, and remained on the bottom of Stockholm harbour for 333 years. Raised in 1961, she became the first large-scale wooden object to be treated with polyethylene glycol (PEG). In the summer of 2000 a number of acidic salt precipitations were noticed on the surface of the ship and on wooden artefacts in the storerooms. An international research project has been established to look into the causes of this problem and suggest possible re-treatments. Meanwhile projects are underway to monitor movements in the ship, to build a better support system, and to replace the thousands of iron bolts holding the structure together, while a sophisticated new climate system has recently been installed in the museum.     

液滴荧光传感与计算机联用技术在微量分析中的应用

通过在LS55型荧光-磷光-发光分光光度计上加装液滴产生及调节附件,采用计算机采集与分析处理数据,成功地研制了双通道液滴光化学传感装置.利用葡聚糖凝胶对复合维生素B中不同组分的选择性吸附来达到分离与同时检测的目的,并将其用于复合维生素B药片的分析,取得了满意的结果.     

On the scaling of the interface energy of the liquid clusters in the disordered nanoporous medium

Similarity of the extrusion curves of non-wetting liquid in a nanoporous medium with different initial fill volume fractions is observed experimentally. The similarity can be explained by the scaling of the interface energy and the self-similarity of the infinite percolation cluster of fluid-filled pores. Understanding the physical processes leading to the observed phenomena is a foundation for the development of high-performance devices for damping and energy storage on the basis of such heterogeneous systems.     

Using of the Agglomeration-in-liquid for the Technology of the Fine Materials

The content of the fine and ultrafine particles in the raw material results in difficulty of the separation, the loss of the valuable components and ecological contamination. Secondary using of the fine particles is impossible without their granulation. This problem has been solved by the agglomeration-in-liquid method.An agglomeration-in-liquid method is a process to produce agglomerates in a liquid phase from solid particles suspended in the liquid. The surface of solid particles and the binding liquid must be of identical polarity, but the continuous phase must be of the opposite polarity. The water solutions of the surfactant are the binding liquids or the organic liquids.     

Copper-containing dendromesogens: the influence of the metal on the mesomorphism

The synthesis and liquid crystalline behaviour of the first and second generations of a dendrimeric structure based on poly(propyleneimine)(DAB-dendr(NH₂)_x) are reported. 4-(4-n-Alkoxybenzoyloxy)salicylaldehydes are used as mesogenic moieties attached at the peripheral amino groups of the dendrimers giving rise to dendromesogens with four and eight mesogenic branches. From these dendromesogens, considered as organic ligands, were prepared six metal-containing dendrimers which incorporate two or four copper atoms in their structures. All the dendrimeric ligands and three of the metal-containing dendrimers exhibit liquid crystalline properties which were studied by optical microscopy, DSC, X-ray diffraction and EPR spectroscopy.     

光亮剂对银电沉积行为的影响

用电势阶跃法和旋转圆盘电极法 (RDE)以及SEM和XRD测试手段 ,初步研究了光亮剂对氰化体系中银电沉积行为的影响 .研究表明 ,光亮剂的加入并未导致银电沉积成核机理的改变 ,但显著增强了镀液的微观平整效应 ,并且所得镀层的表观光滑程度明显改善 .XRD测试亦同时表明光亮剂的加入并未改变镀层的择优取向     

Influence of the Position of the Connecting Spacer of the Chromophore on the Nonlinear Optical Response

A new chromophore, C1 , based on a similar DπA‐structure as in the FTC ‐chromophore but with a hydroxyalkyl spacer perpendicular to the direction of the dipole moment was synthesized. Both chromophores and the CLD ‐chromophore were used to prepare high T_g nonlinear optical vinyl polymers. The influence of the position of the spacer on the DπA‐system on the NLO response of the resulting polymers was investigated.

     

On the dependence of the critical supersaturation on the initial undersaturation in the reverse Wilson chamber

The dependence of the critical supersaturation on the degree of the initial undersaturation has been analyzed in detail.This dependence is explained by means of the Richarch-Powell equation, taking into account the dependence of the -ratio upon the partial pressures of the inert gas and the liquid under investigation.