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51.
de Vargas-Sansalvador IM Fay C Phelan T Fernández-Ramos MD Capitán-Vallvey LF Diamond D Benito-Lopez F 《Analytica chimica acta》2011,(2):216-222
A new system for CO2 measurement (0–100%) based on a paired emitter–detector diode arrangement as a colorimetric detection system is described. Two different configurations were tested: configuration 1 (an opposite side configuration) where a secondary inner-filter effect accounts for CO2 sensitivity. This configuration involves the absorption of the phosphorescence emitted from a CO2-insensitive luminophore by an acid–base indicator and configuration 2 wherein the membrane containing the luminophore is removed, simplifying the sensing membrane that now only contains the acid–base indicator. In addition, two different instrumental configurations have been studied, using a paired emitter–detector diode system, consisting of two LEDs wherein one is used as the light source (emitter) and the other is used in reverse bias mode as the light detector. The first configuration uses a green LED as emitter and a red LED as detector, whereas in the second case two identical red LEDs are used as emitter and detector. The system was characterised in terms of sensitivity, dynamic response, reproducibility, stability and temperature influence. We found that configuration 2 presented a better CO2 response in terms of sensitivity. 相似文献
52.
设计了一台3000A液态下阴极电解槽,阴极为轧制钨板设置在槽底部,电解过程中阴极表面形成一层金属液而充当液态阴极作用,继续析出的金属流入坩埚中,阳极为方块状石墨块,由导杆悬挂于可升降的水平导电母线上,阴极处于阳极投影下方,阴阳极之间水平平行布置.在此设计的电解槽上进行金属钕的电解试验,电解槽稳定运行,电解槽电压与传统上插阴阳极式电解槽相比,槽电压大幅降低至6V以内,电流效率达到80%以上,本文还考察了该电解槽的电压分布情况、电流电压曲线、电解槽的热场分布情况. 相似文献
53.
The principles of electrolysis and facilitated ion transfer at the interface of two immiscible electrolyte solutions are outlined. The method of determination of ionophores is exemplified by assay of monensin in cultures ofStreptomyces cinnamonensis.Dedicated to Professor W. Simon on the occasion of his 60th birthday 相似文献
54.
55.
In the one compartment electrochemical cell 2‐hydroxy‐2‐p‐tolyl‐butyric acid methyl ester was electrosynthesized by electrochemical carboxylation of p‐methylpropiophenone in the presence of carbon dioxide. Under galvanostatic conditions, the electrocarboxylation was influenced by supporting electrolytes, cathode materials, the current density, passed charge and temperatures. Application scope of the eletrocarboxylation system was then examined, and an excellent yield of 97% was obtained when the electrolysis was carried out in DMF‐0.1 mol·L?1 TEABr solution using cheap and environmentally benign nickel as the cathode under a controlled current density of 5.0 mA·cm?2 until 2.8 F·mol?1 charge passed through the cell at ?10°C. The electrochemical behavior of p‐methoxylacetophenone has been studied on the glassy carbon electrode by cyclic voltammetry and the probable mechanism was proposed accordingly. 相似文献
56.
This paper presents particulate and layered materials used in industry with at least one dimension under 500 nm. The objective is to bring to the attention of researchers areas of investigation where new properties and phenomena may manifest. The most relevant materials are natural and synthetic platelets and spherical and coated silica particles. 相似文献
57.
The degradation of azobenzene (AO) by a gaseous plasma is reported. The plasma was generated in a localized zone between an electrolytic solution and a tip of an anode in contact with the surface of solution by means of contact glow discharge electrolysis. There is an optimum pH for the degradation of AO. Iron (II) had a remarkable catalytic action on it. Furthermore, the degradation followed the first‐order kinetic law. Some of the intermediate products of the degradation process were detected by HPLC. 相似文献
58.
Oxidative Degradation of Aqueous Cresols Induced by Gaseous Plasma with Contact Glow Discharge Electrolysis 总被引:2,自引:0,他引:2
The oxidative degradation of cresols smoothly proceeded toward inorganic end products when a gaseous plasma generated by means
of dc glow discharge was sustained in contact with the surface of aqueous solution containing organic compounds. In order
to get mechanistic insight, the monohydroxylation products from each isomeric cresol were closely examined as primary intermediates
to reveal that the aromatic hydroxylation preferentially occurred at the position para to the hydroxyl group of each starting
material. It was also established that the degradation of cresols strictly followed the first-order rate law. On the basis
of the orientational analysis and the kinetical consideration including the effects of Fe ions added on the reaction rate,
it was concluded that hydroxyl radical, which might result from the homolytic cleavage of water molecules by the action of
plasma, was the most likely reagent responsible for the mineralization of cresols. 相似文献
59.
Wei-Jing Gao Chiu Marco Lam Bao-Guo Sun R. Daniel Little Cheng-Chu Zeng 《Tetrahedron》2017,73(17):2447-2454
The electrochemically oxidative cleavage of lignin β-O-4 model compounds mediated by iodide ion has been studied. The results indicate that electrolytic conditions play a predominant role in determining the distribution of cleavage products. The preparative-scale electrolysis proceeds in a simple undivided cell, employing a catalytic amount of NaI as the redox mediator and supporting electrolyte in methanol. Under these conditions, the CβO bond is selectively cleaved with 2,2-dimethoxy-2-arylacetaldehyde being the main product. In some cases, the reaction gives a good yield of cleavaged products. The results further demonstrate that the indirect electrolysis mediated by halide is a versatile approach for chemical transformation. 相似文献
60.
FANG YaHui & LIU ZhiPan Shanghai Key Laboratory of Molecular Catalysis Innovative Materials 《中国科学:化学》2010,(3)
Theoretical simulations on complex electrochemical processes have been developed on the basis of the understanding in electrochemistry,which has benefited from quantum mechanics calculations.This article reviews the recent progress on the theory and applications in electrocatalysis.Two representative reactions,namely water electrolysis and oxygen reduction,are selected to illustrate how the theoretical methods are applied to electrocatalytic reactions.The microscopic nature of these electrochemical reaction... 相似文献