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Reconstruction of emission coefficients for a Non-axisymmetric Coupling Arc Based on MALDONADO's Method

Chinese Journal of Mechanical Engineering 2012年第4期25卷 781-785页

作者： XIONG Jun ZHANG Guangjun HU Yutang WU Lin State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology Harbin 150001 China

The reconstruction of emission coefficient is a key factor for the calculation of temperature ***,most of the researches for determining arc plasmas are based on axisymmetric sources,little has been done to study non-axisymmetric arc *** order to reveal temperatures of a non-axisymmetric coupling arc,the distribution of emission coefficients must be reconstructed in *** this paper,the argon atomic line intensities of the coupling arc are obtained by using the imaging system that involves a high speed camera in conjunction with a neutral and a narrow-band *** converted programme between emission coefficients and emitted intensities is programmed based on MALDONADO＇s method.A displaced Gaussian model is used for evaluating the validity of the converted ***,the emission coefficients of a free burning arc are reconstructed by MALDONADO＇s method and an Abel inversion,respectively,and good agreement is ***,the emission coefficient profiles of the coupling arc are *** results show that the distribution of emission coefficient for the coupling arc is *** emission coefficient profile is similar to an ellipse,and the short axis of the ellipse is in the direction that the two electrodes are arranged *** peak temperature of the coupling arc is in the middle of both *** is a strong interaction between both arcs within the coupling *** proposed research solves difficulties for determining asymmetric arcs and enlarges the application scope of spectroscopic techniques.

关键词： non-axisymmetric coupling arc emission coefficient Twin-electrode TIG spectroscopy image

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Thermal radiation properties of PTFE plasma

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Plasma Science and Technology 2017年第6期19卷 82-88页

作者： Xiangyang LIU Siyu WANG Yang ZHOU Zhiwen WU Kan XlE Ningfei WANG School of Aerospace Engineering Beijing Institute of Technology Beijing 100081 People＇s Republic of China

To illuminate the thermal transfer mechanism of devices adopting polytetrafluoroethylene（PTFE） as ablation materials,the thermal radiation properties of PTFE plasma are calculated and discussed based on local thermodynamic equilibrium（LTE） and optical thin *** is clarified that line radiation is the dominant mechanism of PTFE *** emission coefficient shows an opposite trend for both wavelength regions divided by 550 nm at a temperature above15 000 *** emission coefficient increases with increasing temperature and ***,it has a good log linear relation with *** emissivity varies complexly with temperature,and has a critical point between 20 000 K to 25 000 *** equivalent cross points of the average ionic valence and radiation property are about 10 000 K and 15 000 K for fully single ionization.

关键词： PTFE plasma radiation emission coefficient ablation emissivity

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emission Characteristics of Soil Nitrous Oxide from Typical Greenhouse Vegetable Fields in North China

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Agricultural Science & Technology 2017年第3期18卷 438-442页

作者：徐钰刘兆辉魏建林石璟谭德水王梅李国生江丽华山东省农业科学院农业资源与环境研究所/农业部黄淮海平原农业环境重点实验室/山东省植物营养与肥料重点实验室山东济南250100

To make clear the emission characteristics of soil N20 from typical green- house vegetable fields in North China, an experiment was conducted in greenhouse tomato field in Shouguang city, Shandong province, China＇s ＂Home of Vegetables＂. The N2O fluxes were observed in four experimental treatments, as follows： none N fertilizer （CK）, single organic fertilizer （OM）, conventional fertilization （FP） and opti- mized and reduced nitrogen fertilization （OPT）, by a close chamber-gas chromato- graph method. The effects of different fertilization treatments on N2O emission and tomato yield were analyzed. The results showed that following the fertilization and ir- rigation, the pulsed emissions of N2O were measured. The N2O emission peak ap- peared after basal fertilizer application and irrigation and could be maintained for about 20 days. While the N2O emission peak caused by topdressing was smaller and last only 3-5 days. The statistical analysis showed that the N2O fluxes were affected by air temperature, soil temperature and WFPS at soil depth of 3 cm. The total contents of soil N2O fluxes had significant differences among experimental groups. The total content orderly was FP of 14. 77 kg/hm^2, OPT of 9. 73 kg/hm^2, OM of 6.84 kg/hm^2 and CK of 2.37 kg/hm^2. The N~：~ emission coefficient ranged from 0.83%-1.10%,which was close to or more than the recommended value （1.0%） by IPCC. Compared with the FP treatment, the tomato yield in OPT treatment, whose application rate of chemical N fertilizer decreased by about 60%, increased by 2.2%. Under the current management measures, the reasonable reduction on ap- plicaUon rate of organic manure and chemical nitrogen fertilizer could effectively re- duce the N=O emissions in greenhouse vegetable fields.

关键词： Greenhouse vegetable field N2O emission characteristic Influencingfactor emission coefficient Tomato yield

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