The reactions of several phenols with 2, 2,6,6-tetramethyl-4-methoxypiperidine oxoammonium chloride were stUdied.It was found that ha oxoammonium salt is a facile reagent for the oxidative coupling of phenols.o-substi...The reactions of several phenols with 2, 2,6,6-tetramethyl-4-methoxypiperidine oxoammonium chloride were stUdied.It was found that ha oxoammonium salt is a facile reagent for the oxidative coupling of phenols.o-substituted phenols gave the para-para-coupling products and p- substituted phenols gave the ortho-ortho-coupling products,while o-,p-substituted phenol gave the corresponding dehydrogenated coupling product.展开更多
U.V. irradiation of N-methylphenothiazine 1 in carbon tetrachloride produced 3-(phenothiazin-N-yl-carbonyl)-N-methylphenothiazine 2 together with the radical cation salt 1(+) CCl4- and methyl chloride, presumably via ...U.V. irradiation of N-methylphenothiazine 1 in carbon tetrachloride produced 3-(phenothiazin-N-yl-carbonyl)-N-methylphenothiazine 2 together with the radical cation salt 1(+) CCl4- and methyl chloride, presumably via a photoinduced electron transfer mechanism.展开更多
U.V. irradiation of N,N-dimethylaniline (DMA) in the presence of 7,7-dichloronorcarane (DCN) in acetonitrile solution produces N-methyianiline, 4,4'-methylenebis-(N,N-dimethylaniline), N-(4'-N',N'-dime...U.V. irradiation of N,N-dimethylaniline (DMA) in the presence of 7,7-dichloronorcarane (DCN) in acetonitrile solution produces N-methyianiline, 4,4'-methylenebis-(N,N-dimethylaniline), N-(4'-N',N'-dimethylaminobenzyl)-N-methylaniline and 7-chloronorcarane as the major products. A photoinduced electron transfer mechanism is proposed.展开更多
The effect of graphite particulate reinforcement on the resultant damping behaviour of ZA27 metal matrix composites (MMCs) has been investigated in an effort to develop a new functional material. The MMCs were process...The effect of graphite particulate reinforcement on the resultant damping behaviour of ZA27 metal matrix composites (MMCs) has been investigated in an effort to develop a new functional material. The MMCs were processed by a spray atomization and deposition technique. The damping capacity, as well as the relative dynamic modulus, was measured at frequencies of 1 and 4 Hz in the 30 to 200 degrees C temperature range. There exists a transformation point at 55 degrees C in the internal friction and temperature spectrum of the MMCs. It is shown from microstructural analysis that the damping capacity of ZA27 can be significantly improved by the addition of graphites particulates through spray deposition processing. Finally, the operative damping mechanism is discussed in light of the data obtained from characterization of microstructure and damping capacity.展开更多
A novel composite membrane of poly(vinyl alcohol) and regenerated silk fibroin was employed to immobilize horseradish peroxidase (HRP) and IR was used to give a useful insight into the structure of the composite membr...A novel composite membrane of poly(vinyl alcohol) and regenerated silk fibroin was employed to immobilize horseradish peroxidase (HRP) and IR was used to give a useful insight into the structure of the composite membrane before and after ethanol treatment. A methylene green-mediated sensor sensitive to hydrogen peroxide was fabricated, based on the composite membrane as immobilization matrix for HRP. Cyclic voltammetry and amperometric measurement were for the first time utilized to demonstrate the suitability of methylene green as an electron transfer mediator between immobilized HRP and a glassy carbon electrode in bioelectrocatalytic reduction of hydrogen peroxide. Performance and characteristics of the sensor were evaluated in respect to response time, detection limit, applied potential and concentration of the mediator. The sensor possesses a variety of characteristics including good sensitivity, rapid response time and low detection of limit of 0.1 mu mol/L.展开更多
文摘The reactions of several phenols with 2, 2,6,6-tetramethyl-4-methoxypiperidine oxoammonium chloride were stUdied.It was found that ha oxoammonium salt is a facile reagent for the oxidative coupling of phenols.o-substituted phenols gave the para-para-coupling products and p- substituted phenols gave the ortho-ortho-coupling products,while o-,p-substituted phenol gave the corresponding dehydrogenated coupling product.
文摘U.V. irradiation of N-methylphenothiazine 1 in carbon tetrachloride produced 3-(phenothiazin-N-yl-carbonyl)-N-methylphenothiazine 2 together with the radical cation salt 1(+) CCl4- and methyl chloride, presumably via a photoinduced electron transfer mechanism.
文摘U.V. irradiation of N,N-dimethylaniline (DMA) in the presence of 7,7-dichloronorcarane (DCN) in acetonitrile solution produces N-methyianiline, 4,4'-methylenebis-(N,N-dimethylaniline), N-(4'-N',N'-dimethylaminobenzyl)-N-methylaniline and 7-chloronorcarane as the major products. A photoinduced electron transfer mechanism is proposed.
文摘The effect of graphite particulate reinforcement on the resultant damping behaviour of ZA27 metal matrix composites (MMCs) has been investigated in an effort to develop a new functional material. The MMCs were processed by a spray atomization and deposition technique. The damping capacity, as well as the relative dynamic modulus, was measured at frequencies of 1 and 4 Hz in the 30 to 200 degrees C temperature range. There exists a transformation point at 55 degrees C in the internal friction and temperature spectrum of the MMCs. It is shown from microstructural analysis that the damping capacity of ZA27 can be significantly improved by the addition of graphites particulates through spray deposition processing. Finally, the operative damping mechanism is discussed in light of the data obtained from characterization of microstructure and damping capacity.
基金Project supported by Shanghai Natural Science Foundation for Young Scientists,Natural Science Foundation of Shanghai Higher Education Bureau for Young Scientists,the National Natural Science Foundation of China and Open Electroanalytical Chemistry Labora
文摘A novel composite membrane of poly(vinyl alcohol) and regenerated silk fibroin was employed to immobilize horseradish peroxidase (HRP) and IR was used to give a useful insight into the structure of the composite membrane before and after ethanol treatment. A methylene green-mediated sensor sensitive to hydrogen peroxide was fabricated, based on the composite membrane as immobilization matrix for HRP. Cyclic voltammetry and amperometric measurement were for the first time utilized to demonstrate the suitability of methylene green as an electron transfer mediator between immobilized HRP and a glassy carbon electrode in bioelectrocatalytic reduction of hydrogen peroxide. Performance and characteristics of the sensor were evaluated in respect to response time, detection limit, applied potential and concentration of the mediator. The sensor possesses a variety of characteristics including good sensitivity, rapid response time and low detection of limit of 0.1 mu mol/L.
