A low voltage circuit breaker(LVCB)is an important piece of protection equipment which will switch off the fault current in a power system.The moving contact of a low voltage circuit breaker with a higher rated curren...A low voltage circuit breaker(LVCB)is an important piece of protection equipment which will switch off the fault current in a power system.The moving contact of a low voltage circuit breaker with a higher rated current consists of two parallel contacts.Therefore,the convection effect on the air arc evolution process in a two parallel contact system is analyzed.A threedimensional(3 D)magneto–hydro–dynamic(MHD)model of arc simulation is built.In this model,the anode consists of two parallel contacts and a bonding conductor.A nonlinear voltage–current density characteristic is employed to represent the near-anode and near-cathode voltage.The current density,arc voltage and currents through every contact are obtained.The influence of convection and conduction on the arc evolution process are quantitatively calculated.The displacements of the arc roots are obtained and the asymmetry of the arc root motion is analyzed.The arc evolution process of a two parallel contact system is preliminarily revealed.展开更多
Heme is a key cofactor in aerobic life, both in eukaryotes and prokaryotes. Because of the high reactivity of ferrous protoporphyrin IX, the reactions of heme in cells are often carried out through heme-protein comple...Heme is a key cofactor in aerobic life, both in eukaryotes and prokaryotes. Because of the high reactivity of ferrous protoporphyrin IX, the reactions of heme in cells are often carried out through heme-protein complexes. Traditionally studies of heme-binding proteins have been approached on a case by case basis, thus there is a limited global view of the distribution of heme-binding proteins in different cells or tissues. The procedure described here is aimed at profiling heme-binding proteins in mouse tissues sequentially by 1) purification of heme-binding proteins by heme-agarose, an affinity chromatographic resin; 2) isolation of heme-binding proteins by SDS-PAGE or two-dimensional electrophoresis; 3) identification of heme-binding proteins by mass spectrometry. In five mouse tissues, over 600 protein spots were visualized on 2DE gel stained by Commassie blue and 154 proteins were identified by MALDI-TOF, in which most proteins belong to heme related. This methodology makes it possible to globally characterize the heme-binding proteins in a biological system.展开更多
基金supported by the Natural Science Foundation of Shaanxi Province of China(No.2017ZDJC-16)Shenzhen Power Supply Co.Ltd(No.SZKJXM20170480).
文摘A low voltage circuit breaker(LVCB)is an important piece of protection equipment which will switch off the fault current in a power system.The moving contact of a low voltage circuit breaker with a higher rated current consists of two parallel contacts.Therefore,the convection effect on the air arc evolution process in a two parallel contact system is analyzed.A threedimensional(3 D)magneto–hydro–dynamic(MHD)model of arc simulation is built.In this model,the anode consists of two parallel contacts and a bonding conductor.A nonlinear voltage–current density characteristic is employed to represent the near-anode and near-cathode voltage.The current density,arc voltage and currents through every contact are obtained.The influence of convection and conduction on the arc evolution process are quantitatively calculated.The displacements of the arc roots are obtained and the asymmetry of the arc root motion is analyzed.The arc evolution process of a two parallel contact system is preliminarily revealed.
文摘Heme is a key cofactor in aerobic life, both in eukaryotes and prokaryotes. Because of the high reactivity of ferrous protoporphyrin IX, the reactions of heme in cells are often carried out through heme-protein complexes. Traditionally studies of heme-binding proteins have been approached on a case by case basis, thus there is a limited global view of the distribution of heme-binding proteins in different cells or tissues. The procedure described here is aimed at profiling heme-binding proteins in mouse tissues sequentially by 1) purification of heme-binding proteins by heme-agarose, an affinity chromatographic resin; 2) isolation of heme-binding proteins by SDS-PAGE or two-dimensional electrophoresis; 3) identification of heme-binding proteins by mass spectrometry. In five mouse tissues, over 600 protein spots were visualized on 2DE gel stained by Commassie blue and 154 proteins were identified by MALDI-TOF, in which most proteins belong to heme related. This methodology makes it possible to globally characterize the heme-binding proteins in a biological system.
