Digital pulse processing has developed rapidly during recent years.Moreover,it has been widely applied in many fields.In this study,we introduce a digital pulse processing method for 2πa and 2πb emitter measurement....Digital pulse processing has developed rapidly during recent years.Moreover,it has been widely applied in many fields.In this study,we introduce a digital pulse processing method for 2πa and 2πb emitter measurement.Our digital pulse processing method for 2πa and 2πb emitter measurement is comprised of a field-programmable gate-array-based acquisition card and a pulse-height analysis routine.We established two channels(one for the a emitter and one for the b emitter) on an acquisition board using an analog-to-digital converter with a 16-bit resolution at a speed of 100 million samples per second.In this study,we used captured and stored data to analyze emission rate counts and spectrums.The method we established takes into account noise cancelation,dead-time correction,background subtraction,and zero-energy extrapolation.We carefully designed control procedures in order to simplify pulse-width fitting and threshold-level setting.We transmitted data and commands through a universal serial bus between the acquisition board and the computer.The results of our tests prove that our method performs well in pulse reconstruction fidelity and amplitude measurement accuracy.Compared with the current standard method for measuring 2πa and 2πb emission rates,our system demonstrates excellent precision in emission rate counting.展开更多
Due to an increasing environmental pollution, a search for the cost effective treatment and disposal of the dyes from the textile effluents is getting more and more importance. Oxidation and reduction processes play i...Due to an increasing environmental pollution, a search for the cost effective treatment and disposal of the dyes from the textile effluents is getting more and more importance. Oxidation and reduction processes play important roles in the degradation treatments of the azo dyes. The latter process is more effective and in consequence its mechanism is also better understood. The mechanism of the oxidation processes, the intermediates involved in these reactions and their role in the effectiveness of the oxidative degradation of the azo dyes, viz, phenyl azo b-naphthol (PAN), Sudan I. On exposure to sunlight at 2 1/2 hours for various samples in different concentrations of PAN mixed with Fenton reagent, when the reactive intermediate?reacted with the colour, the pH vs. absorbance generally showed significant degradation in between pH 5 and 6. The results were compared with the same samples on exposure to uv-light of 254 nm and irradiated at 20 minutes. The degradation occurred in samples of relatively high concentrations, viz, 10-3 and 5 × 10-4 mol· dm-3 at near neutral pH 6 whereas. Low concentration samples such as 10-4 and 5 × 10-5 mol·dm-3 showed degradation towards more acidic range of pH 2 to 4. In advanced oxidation process (AOP), generally reactive, strongly oxidizing ·OH radicals play a main role in destruction of the dye molecules. The proposed mechanisms and the rate coefficients for the reactions of ·OH intermediates with the dye molecules and with model compounds are summarized.展开更多
文摘Digital pulse processing has developed rapidly during recent years.Moreover,it has been widely applied in many fields.In this study,we introduce a digital pulse processing method for 2πa and 2πb emitter measurement.Our digital pulse processing method for 2πa and 2πb emitter measurement is comprised of a field-programmable gate-array-based acquisition card and a pulse-height analysis routine.We established two channels(one for the a emitter and one for the b emitter) on an acquisition board using an analog-to-digital converter with a 16-bit resolution at a speed of 100 million samples per second.In this study,we used captured and stored data to analyze emission rate counts and spectrums.The method we established takes into account noise cancelation,dead-time correction,background subtraction,and zero-energy extrapolation.We carefully designed control procedures in order to simplify pulse-width fitting and threshold-level setting.We transmitted data and commands through a universal serial bus between the acquisition board and the computer.The results of our tests prove that our method performs well in pulse reconstruction fidelity and amplitude measurement accuracy.Compared with the current standard method for measuring 2πa and 2πb emission rates,our system demonstrates excellent precision in emission rate counting.
基金Project （50405026） supported by the National Natural Science Foundation of China Project（20051022） supported by the Department of Science and Technology of Shanxi Province, China
文摘Due to an increasing environmental pollution, a search for the cost effective treatment and disposal of the dyes from the textile effluents is getting more and more importance. Oxidation and reduction processes play important roles in the degradation treatments of the azo dyes. The latter process is more effective and in consequence its mechanism is also better understood. The mechanism of the oxidation processes, the intermediates involved in these reactions and their role in the effectiveness of the oxidative degradation of the azo dyes, viz, phenyl azo b-naphthol (PAN), Sudan I. On exposure to sunlight at 2 1/2 hours for various samples in different concentrations of PAN mixed with Fenton reagent, when the reactive intermediate?reacted with the colour, the pH vs. absorbance generally showed significant degradation in between pH 5 and 6. The results were compared with the same samples on exposure to uv-light of 254 nm and irradiated at 20 minutes. The degradation occurred in samples of relatively high concentrations, viz, 10-3 and 5 × 10-4 mol· dm-3 at near neutral pH 6 whereas. Low concentration samples such as 10-4 and 5 × 10-5 mol·dm-3 showed degradation towards more acidic range of pH 2 to 4. In advanced oxidation process (AOP), generally reactive, strongly oxidizing ·OH radicals play a main role in destruction of the dye molecules. The proposed mechanisms and the rate coefficients for the reactions of ·OH intermediates with the dye molecules and with model compounds are summarized.
