Cu对Cu—Mn—Ce—O和Cu—Mn—Ce—Pd—O催化剂三效性能的影响

利用火焰脉冲－微反装置考察了Ｃｕ－Ｍｎ－Ｃｅ－Ｏ和Ｃｕ－Ｍｎ－Ｃｅ－Ｐｄ－Ｏ两类催化剂的三效活性。结果表明Ｃｕ的加入有利Ｃｕ－Ｍｎ－Ｃｅ－Ｏ的ＮＯｘ和ＣＯ的转化，而不利于Ｃｕ－Ｍｎ－Ｃｅ－Ｐｄ－Ｏ的ＮＯｘ和ＨＣ的转化。ＸＲＤ分析结果表明在Ｃｕ－Ｍｎ－Ｃｅ－Ｏ中加入Ｐｄ，原来的ＣｕＭｎ２Ｏ３消失，生成新相ＭｎＡｌ２Ｏ４；ＴＰＲ分析结果表明Ｃｕ使Ｍｎ－Ｃｅ－Ｏ样品表面氧量增加，表面易于还原，而使Ｍｎ－     

钴铜锰镍的HPLC的研究及其在中草药微量元素形态分析中的应用

本在对Ｃｄ、Ｃｏ、Ｃｕ、Ｆｅ、Ｍｎ、Ｎｉ、Ｓｅ、Ｚｎ的二乙基二硫代氨基甲酸螯合物ＨＰＬＣ行为研究的基础上，提出了Ｃｏ、Ｃｕ、Ｍｎ、Ｎｉ的反相ＨＰＬＣ法，并用于中经中这些元素的初级形态分析。     

Cu对Cu－Mn－Ce－O和Cu－Mn－Ce－Pd－O催化剂三效性能的影响

利用火焰脉冲－微反装置考察了Ｃｕ－Ｍｎ－Ｃｅ－Ｏ和Ｃｕ－Ｍｎ－Ｃｅ－Ｐｄ－Ｏ两类催化剂的三效活性。结果表明Ｃｕ的加入有利于Ｃｕ－Ｍｎ－Ｃｅ－Ｏ的ＮＯｘ和ＣＯ的转化，而不利于Ｃｕ－Ｍｎ－Ｃｅ－ｐｄ－Ｏ的ＮＯｘ和ＨＣ的转化。ＸＲＤ分析结果表明在Ｃｕ－Ｍｎ－Ｃｅ－Ｏ中加入Ｐｄ，原来的ＣｕＭｎ＿２Ｏ＿３消失，生成新相ＭｎＡｌ＿２Ｏ＿４；ＴＰＲ分析结果表明Ｃｕ使Ｍｎ－Ｃｅ－Ｏ样品表面氧量增加，表面易于还原，而使Ｍｎ－Ｃｅ－ｐｄ－Ｏ样品表面难于还原。实验结果还表明Ｍｎ－Ｃｅ－ｐｄ－Ｏ催化剂的三效性能远远优于Ｃｕ－Ｍｎ－Ｃｅ－Ｏ催化剂。     

Ce掺杂对SnO2薄膜电学及气敏性能的影响

以无机盐ＳｎＣｌ２．２Ｈ２Ｏ（Ｎ４）３Ｃｅ（ＮＯ３）６为原料，无水乙醇为溶剂，采用溶胶－凝胶工艺制备了纯ＳｎＯ２及ＳｎＯ２：Ｃｅ薄膜。研究了ＳｎＯ２：Ｃｅ薄膜的热分解晶化过程和Ｃｅ掺杂和ＳｎＯ２薄膜的及气敏性能的影响，发现ＳｎＯ２：Ｃｅ薄膜在常温下对Ｈ２Ｓ气体具有较妇的敢敏性能，对ＳｎＯ２：Ｃｅ薄膜的结构进行了表征。     

导电高聚物聚2，5－二甲基苯胺的化学合成与特性

报道了聚２，５－二甲基苯胺（ＰＤＭｅＡｎ）的化学合成，并用标准四探针方法测定其电导率，以ＦＴＩＲ、ＵＶ－Ｖｉｓ吸收光谱、元素分析和ＣＶ法对其性质进行了研究，ＰＤＭｅＡｎ的结构与聚苯胺和聚２，５－二甲氧基苯胺的结构类似，是由其单元通过氮原子（Ｎ）在对位上键合而成，本征态的ＰＤＭｅＡｎ能溶于多种有机溶剂，如ＣＨ２Ｃｌ２、ＣＨＣｌ３、ＤＭＳＯ、ＤＭＦ等。     

氧化铈对氧化锰结构和催化性能的影响

以共沉淀法制备了铈－锰混合氧化物催化剂，采用Ｘ射线衍射分析、程序升温脱附－质谱检测、程度升温还原等手段考察了催化剂的结构还原活性及表面氧脱附性能。结果表明，单组分ＭＮ－Ｏ催化剂的晶相结构为方铁锰矿型Ｍｎ２Ｏ３，双组分Ｍｎ－Ｃｅ－Ｏ催化剂为γＭｎ２Ｏ３和ＣｅＯ２。氧化铈的存在不影响氧化锰ＴＰＤ－Ｏ２特征峰的位置，但表面吸附氧量明显增加，并同催化剂对甲醇的完全氧化活性进行了关联，当Ｍｎ／Ｃｅ原子比为４     

在线的离子交换预富集流动注射—原子吸收光谱法测定铁,锰,…

本文使用大孔弱酸阳离子交换树脂Ｄ－１５２微型柱预富集，将流动注射与原子吸收光谱法相结合测定了Ｆｅ，Ｍｎ，Ｃｕ和Ｃｄ等离子，讨论了溶液酸度，采样速率及洗脱剂等对上述四元素灵敏度的影响，在采样频率４０次／ｈ，采样体种７ｍｌ地Ｆｅ，Ｍｎ，Ｃｕ和Ｃｄ增敏１６－２４倍，检出限分别为０．９、０．４、０．４和０．１ｎｇ／ｍｌ     

在线的离子交换预富集流动注射──原子吸收光谱法测定铁、锰、铜和镉的研究

本文使用大孔弱酸阳离子交换树脂Ｄ—１５２微型柱预富集，将流动注射与原子吸收光谱法相结合测定了Ｆｅ、Ｍｎ、Ｃｕ和Ｃｄ等离子。讨论了溶液酸度、采样速率及沈脱剂等对上述四元素灵敏度的影响。在采样频率４０次／ｈ、采样体积７ｍｌ时，Ｆｅ、Ｍｎ、Ｃｕ和Ｃｄ增敏１６～２４倍，检出限分别为０．９、０．４、０．４和０．１ｎｇ／ｍｌ。     

Ce2O—TiO2／SiO2的制备及除氟性能研究

以ＳｉＯ２为基质，ＣｅＯ２ＴｉＯ２为包覆物质，采用溶胶凝胶法制备ＣｅＯ２ＴｉＯ２／ＳｉＯ２表面复合物，并对所制复合物进行除氟测试。用扫描电镜（ＳＥＭ）观察表面形貌，讨论实验环境、试剂用量等因素对ＣｅＯ２ＴｉＯ２／ＳｉＯ２制备及除氟性能的影响，结果表明：ｎＴｉ（ＯＣ４Ｈ９）４／ｎＣｅＣｌ３·７Ｈ２Ｏ＝１、ｎＣＨ３ＣＯＯＨ／ｎＴｉ（ＯＣ４Ｈ９）４＝４５、ｎＣ３Ｈ８Ｏ３／ｎＴｉ（Ｏ４Ｈ９）４＝０３、ＲＨ＝９５％，热处理温度１１０℃时，所制ＣｅＯ２ＴｉＯ２／ＳｉＯ２对Ｆ－的吸附容量（ｑ）为２１４ｍｇ／ｇ，去除率（Ｅ）为８５６％。     

菊花微量及宏量元素分析

用ＩＣＰ－ＡＥＳ法测定了药用野菊花和抗白菊及６种人工栽培菊花中Ａｓ，Ｂ、Ｂａ、Ｃａ、Ｃｄ、Ｃｏ、Ｃｕ、Ｆｅ、Ｍｇ、Ｍｎ、Ｍｏ、Ｎｉ、Ｐｂ、Ｓｅ、Ｓｉ、Ｖ、Ｚｎ、Ｐ、Ｓ、Ｋ等元素的含量。结果表明：（１）菊花中Ｃａ、Ｍｇ、Ｐ、Ｓ、Ｋ含量很高，Ｂ、Ｆｅ、Ｍｎ、Ｚｎ也有较高的含量；（２）野菊花中Ｂ、Ｃａ、Ｆｅ、Ｍｇ含量较其他品种高、，抗白菊中Ｍｎ、Ｓｅ、Ｓ含量高地其他品种；（３）代栽培的菊花Ｋ、Ｐ含量高于     

Electrochemical behaviour of gold, silver, platinum and palladium on the glassy carbon electrode modified by chitosan and its application

The chitosan-modified glassy carbon electrode can be used as a working electrode for the determination of precious metal elements: Au, Ag, Pt, Pd. In low pH medium, the complex anions of these precious elements combine with the protonated group ---NH₃⁺ in the chitosan molecule in the form of an ion-association complex. These metal ions were selectively enriched and we got sensitive anodic stripping current. These elements content in ore, welding material have been determined by this method. The results were consistent with those from standard sample and ICP atomic emission spectrometry method. The possible mechanism of electrochemical reaction has been proposed by the study of CV, UV and FT-Raman spectrometry.     

Electrodeposition studies of rare earths

The combination of neutron activation analysis (NAA) and electrochemistry has been used to study the deposition behavior of rare earth elements, as it is reported that excepting La, no other rare earths are electrodeposited. The radiotracers of rare earth elements were electrolyzed in an aqueous medium on a graphite electrode by varying the voltage and time of electrodeposition, thereby optimizing the final experimental conditions for quantitative deposition of rare earth elements. The observations are reported in this work.     

A systematic approach to the impedance of surface layers with mixed conductivity forming on electrodes

Electrode impedance can be evaluated on the basis of the electrode reaction kinetics in many systems, even for complicated electrode reactions. However, when a surface layer is present on the electrode surface, the theoretically well-established impedance model of the electrode reaction is often completed with phenomenological equivalent circuit elements in order to achieve the number of time constants as derived from the electrode impedance spectra measured. In these cases, the meaning of the phenomenological equivalent circuit elements are often unclear, though the presence of these elements is helpful to describe the system throughout the frequency domain used for the measurement. In the present work, an attempt will be shown to separate the effect of the electronic and ionic charge transfer in a surface layer and to identify the appropriate equivalent circuits. Examples are shown from the fields of lithium-ion batteries where a solid electrolyte interface as a surface layer is present at the negative electrode and the contribution of various charge carriers may be of importance.     

Multielement Analysis of Whole Blood Using a Capacitively Coupled Microwave Plasma Atomic Emission Spectrometer

A capacitively coupled microwave plasma atomic emission spectrometer (CMP-AES) has been evaluated as a means for the direct analysis of several of the primary and trace elements in whole blood. A tungsten filament spiral electrode was used with the CMP, and whole blood samples were deposited on the electrode and subsequently dried, ashed, and atomized. The emission was measured with a spectrometer and a charge-coupled-device detector. A sample size of only 2 μl was required and the time for each sample run was under 4 min. This method has a wide dynamic range, allowing the determination of both the primary elements in blood and elements present in trace quantities. Potassium, sodium, lithium, magnesium, manganese, and zinc were studied. Good linearity was observed and the concentration levels obtained for these elements were consistent with literature values. The primary advantages of this method are that no sample pretreatment or dilution is required, the instrument cost is low, and the method is capable of simultaneous multielement analysis on small, discrete samples.     

Selektive chemische Trennverfahren für die Aktivierungsanalyse

Relative sensitivity factors (RSF) of 32 elements in the concentration range 1–10⁴ ppm (mass of element/ mass of electrode) have been determined for spark source mass spectrometric analysis. Graphite and silver powder was used as conductive material. The RSF of about two thirds of the elements under investigation were found to be dependent on their concentration in the electrodes. This is thought to be due to volatilization at high temperatures whereby the concentration of these elements at the electrode surfaces is diminished. In general RSF's at silver powder electrodes are higher and necessary sparking times are shorter than those at graphite electrodes. Therefore the use of silver powder for determinations of concentrations <10³ ppm is advantageous although experimental results show greater scatter due to inhomogeneity of the electrode.     

Disposable Amperometric Sensors for Thiols with Special Reference to Glutathione

The antioxidant ‘reduced glutathione’ tripeptide is conventionally called glutathione (GSH). The oxidized form is a sulfur‐sulfur linked compound, known as glutathione disulfide (GSSG). Glutathione is an essential cofactor for antioxidant enzymes; it provides protection also for the mitochondria against endogenous oxygen radicals. The ratio of these two forms can act as a marker for oxidative stress. The majority of the methods available for estimation of both the forms of glutathione are based on colorimetric and electrochemical assays. In this study, electrochemical sensors were developed for the estimation of both GSH and GSSG. Two different types of transducers were used: i) screen‐printed three‐electrode disposable sensor (SPE) containing carbon working electrode, carbon counter electrode and silver/silver chloride reference electrode; ii) three‐electrode disposable system (CDE) consisting of three copper electrodes. 5,5′‐dithiobis(2‐nitrobenzoic acid) (DTNB) was used as detector element for estimation of total reduced thiol content. The enzyme glutathione reductase along with a co‐enzyme reduced nicotinamide adenine dinucleotide phosphate was used to estimate GSSG. By combining the two methods GSH can also be estimated. The detector elements were immobilized on the working electrodes of the sensors by bulk polymerization of acrylamide. The responses were observed amperometrically. The detection limit for thiol (GSH) was less than 0.6 ppm when DTNB was used, whereas for GSSG it was less than 0.1 ppm.     

On the contamination of membrane–electrode assembles of water electrolyzers with solid polymer electrolyte by the elements of titanium alloys

The aspects of contamination of membrane–electrode assemblies of water electrolyzers with solid polymer electrolyte by the elements of titanium alloys (Ti and Fe) are considered. These alloys are used as the material for current collectors/gas-diffusion electrodes, bipolar plates, and other elements of electrolysis system. It is shown that titanium is one of the main impurities that contaminate the membrane and electrocatalytic layers of membrane–electrode assembly in the case that deionized water is used as the reagent. The membrane contamination can lead to the degradation of electrolyzer characteristics and its failure.     

The entry of substances into the plasma of a d.c. arc from the top surface area of an electrode

Using neutron activation analysis the variation with time of the amounts of Cu, Co and Cd left on the top surface area of the electrode were determined when these elements enter the arc in the presence of the additives KCl, KNO₃, K₂SO₄ as well as in the absence of additives. The additives studied lower the rates with which the elements leave the electrode surface, this effect being greater the lower the boiling point of the element. Additive compounds with varying anions affect the rate of evaporation of the elements from the surface of the electrode to different extents due to the effect of the anionic component of the additive on the electrode temperature. The value of the electrode temperature is not the only factor which determines the escape process of the substance from the electrode surface.     

Glassy carbon paste electrodes modified with polyphenol oxidase: Analytical applications

The electrochemical behavior of a glassy carbon paste electrode (GCPE) is evaluated in comparison to that of graphite paste electrode (gPE) and glassy carbon electrode (GCE). Important shifting in the peak potentials and increases in the peak currents for catechol, ascorbic acid, dopamine and hydroquinone were obtained for the GCPE and its usefulness for the development of phenol and catechol biosensors was also evaluated. Both, pure mushroom polyphenol oxidase (PPO) and fresh mushroom tissues were used as biorecognition elements. The effect of the binder percentage in the composite material was also studied. The bioelectrode was used for the determination of dopamine and acetaminophen in pharmaceutical formulations and for the detection of polyphenols in wine and tea. The bioelectrode demonstrated to be very stable as the response remained around 90% after four months at 4 °C.     

伏安法测定天然水中痕量碲

本工作提出在金盘(或金膜)电极上阳极溶出伏安法测定痕量碲,并对测定方法的灵敏度、精确度、回收率及其共存元素的干扰情况等进行了探索。为了测定天然水中ppt级的碲又采用样品事先经巯基棉分离、富集。在0.1M高氯酸底液中测得闽江水中8.1ng/1的碲,东海海水中1.8ng/1的碲,其平均回收误差在10%以下。