This study mainly monitored the dominant bacterial populations and identified the spoilage-related microorganisms of braised chicken meat stored under different CO_(2)-modified atmosphere packaging(MAP)during refriger...This study mainly monitored the dominant bacterial populations and identified the spoilage-related microorganisms of braised chicken meat stored under different CO_(2)-modified atmosphere packaging(MAP)during refrigerated storage using a culture-dependent method and 16S rDNA identification.The quality changes and shelf life of the meat were also measured.The growth rate of total viable count(TVC)in braised chicken was slower with an increase of CO_(2) content in MAP,which also occurred in the remaining bacterial species monitored(lactic acid bacteria,Pseudomonas spp.,Brochothrix thermosphacta).The MAP exerted beneficial effects on the quality of braised chicken,as demonstrated by retarding the production of total volatile basic nitrogen(TVB-N)and delaying lipid oxidation(TBARS test).A total of 14 isolates were identified from braised chickens with different packaging at the end of storage,these included P.fragi(6 isolates),P.psychrophila(2 isolates),Enterococcus faecalis(3 isolates),B.thermosphacta(2 isolates),Staphylococcus equorum(1 isolate).展开更多
This study investigated the effect of different dielectric barrier discharge cold plasma(DBD-CP) treatment voltages on the microbiological growth and quality characteristics of braised chicken during storage at(4 ...This study investigated the effect of different dielectric barrier discharge cold plasma(DBD-CP) treatment voltages on the microbiological growth and quality characteristics of braised chicken during storage at(4 ± 1) ℃. Argon-packed samples were subjected to DBD-CP treatment for 3 min at voltages of 50, 60 and 70 k V. As a result, there was no significant(P > 0.05) difference in L*, a*, b* and p H of braised chicken between control and treatment groups at the same storage time. However, the development of lipid oxidation in DBD-CP treatment samples was slower than that in air-packed samples. Compared to air-packed samples, the reduction of total viable count, yeasts and molds, lactic acid bacteria and Pseudomonads spp. in 70 k V treated samples on day 15 were 3.21, 2.41, 2.44 and 1.96 lg(CFU/g), respectively. The results indicate that DBD-CP treatment could extend the shelf life of braised chicken without negative impacts on quality characteristics.展开更多
We analyze co-seismic displacement field of the 26 December 2004, giant Sumatra–Andaman earthquake derived from Global Position System observations,geological vertical measurement of coral head, and pivot line observ...We analyze co-seismic displacement field of the 26 December 2004, giant Sumatra–Andaman earthquake derived from Global Position System observations,geological vertical measurement of coral head, and pivot line observed through remote sensing. Using the co-seismic displacement field and AK135 spherical layered Earth model, we invert co-seismic slip distribution along the seismic fault. We also search the best fault geometry model to fit the observed data. Assuming that the dip angle linearly increases in downward direction, the postfit residual variation of the inversed geometry model with dip angles linearly changing along fault strike are plotted. The geometry model with local minimum misfits is the one with dip angle linearly increasing along strike from 4.3oin top southernmost patch to 4.5oin top northernmost path and dip angle linearly increased. By using the fault shape and geodetic co-seismic data, we estimate the slip distribution on the curved fault. Our result shows that the earthquake ruptured *200-km width down to a depth of about 60 km.0.5–12.5 m of thrust slip is resolved with the largest slip centered around the central section of the rupture zone78N–108N in latitude. The estimated seismic moment is8.2 9 1022 N m, which is larger than estimation from the centroid moment magnitude(4.0 9 1022 N m), and smaller than estimation from normal-mode oscillation data modeling(1.0 9 1023 N m).展开更多
This paper proposes a high-efficiency PFC rectifier based on multiplexing the switches.Compared with a traditional six-switch PFC rectifier,the proposed rectifier extends the switches’active angle by making use of th...This paper proposes a high-efficiency PFC rectifier based on multiplexing the switches.Compared with a traditional six-switch PFC rectifier,the proposed rectifier extends the switches’active angle by making use of three bridge rectifiers.As a result,lower conduction resistance can be realized for switches.Consequently,system efficiency can be improved.Compared with a traditional six-switch PFC rectifier with doubled switches,the proposed rectifier can achieve almost the same efficiency improvement while no additional switches are needed.Since continuous inductor current is chopped and resulting current pulses cannot be injected into the grid directly,input filter design and resonance damping are discussed for the proposed rectifier.The controller design of the rectifier is analyzed.The inductor current reference is shaped considering the input voltage envelope and forward duties.Finally,the effectiveness of the proposed rectifier is verified through simulations and experiments.展开更多
Stress field plays a key role in geodynamics. In this study, an algorithm to determine the stress tensor and its confidence range from focal mechanism data by using grid search method was proposed. The experiment uses...Stress field plays a key role in geodynamics. In this study, an algorithm to determine the stress tensor and its confidence range from focal mechanism data by using grid search method was proposed. The experiment uses artificial focal mechanism data which were generated by extensional, compression and strike-slip stress regime and different level of noise, shows that the precision of the estimated stress tensor based on this algorithm is greatly improved compared with traditional algorithms. This algorithm has three advantages:(1) The global optimal solution of the stress tensor is determined by fine grid search of 1o×1o×1o×0.01 and local minimum value is avoided; (2) precision of focal mechanism data can be considered, i.e., different weight of the focal mechanism data contributes differently to the process of determining stress tensor; (3) the confidence range of the determined stress tensor can be obtained by using F-test. We apply this algorithm in the boundary zone of China, Vietnam and Laos, and obtain the stress field with SSE-NNW compressive stress direction and NEE-SWW extensional stress direction. The stress ratio is 0.6, which shows that the eigen values of the stress tensor are nearly in arithmetic sequence. The stress field in this region is consistent with the left-lateral strike slip of the Dienbien-Lauangphrabang arc fault. The result will be helpful in studying the geological dynamic process in this region.展开更多
基金financially supported by China Agriculture Research System (Beijing, China, CARS-41-Z06)Nanjing Professor Huang Food Technology Co., Ltd.
文摘This study mainly monitored the dominant bacterial populations and identified the spoilage-related microorganisms of braised chicken meat stored under different CO_(2)-modified atmosphere packaging(MAP)during refrigerated storage using a culture-dependent method and 16S rDNA identification.The quality changes and shelf life of the meat were also measured.The growth rate of total viable count(TVC)in braised chicken was slower with an increase of CO_(2) content in MAP,which also occurred in the remaining bacterial species monitored(lactic acid bacteria,Pseudomonas spp.,Brochothrix thermosphacta).The MAP exerted beneficial effects on the quality of braised chicken,as demonstrated by retarding the production of total volatile basic nitrogen(TVB-N)and delaying lipid oxidation(TBARS test).A total of 14 isolates were identified from braised chickens with different packaging at the end of storage,these included P.fragi(6 isolates),P.psychrophila(2 isolates),Enterococcus faecalis(3 isolates),B.thermosphacta(2 isolates),Staphylococcus equorum(1 isolate).
基金financially supported by the Key R&D Program(Modern Agriculture)of Jiangsu Province(BE2019308)。
文摘This study investigated the effect of different dielectric barrier discharge cold plasma(DBD-CP) treatment voltages on the microbiological growth and quality characteristics of braised chicken during storage at(4 ± 1) ℃. Argon-packed samples were subjected to DBD-CP treatment for 3 min at voltages of 50, 60 and 70 k V. As a result, there was no significant(P > 0.05) difference in L*, a*, b* and p H of braised chicken between control and treatment groups at the same storage time. However, the development of lipid oxidation in DBD-CP treatment samples was slower than that in air-packed samples. Compared to air-packed samples, the reduction of total viable count, yeasts and molds, lactic acid bacteria and Pseudomonads spp. in 70 k V treated samples on day 15 were 3.21, 2.41, 2.44 and 1.96 lg(CFU/g), respectively. The results indicate that DBD-CP treatment could extend the shelf life of braised chicken without negative impacts on quality characteristics.
基金supported by the Special Fund of Fundamental Scientific Research Business Expense for Higher School of Central Government(Projects for creation teams ZY20110101)NSFC 41090294talent selection and training plan project of Hebei university
文摘We analyze co-seismic displacement field of the 26 December 2004, giant Sumatra–Andaman earthquake derived from Global Position System observations,geological vertical measurement of coral head, and pivot line observed through remote sensing. Using the co-seismic displacement field and AK135 spherical layered Earth model, we invert co-seismic slip distribution along the seismic fault. We also search the best fault geometry model to fit the observed data. Assuming that the dip angle linearly increases in downward direction, the postfit residual variation of the inversed geometry model with dip angles linearly changing along fault strike are plotted. The geometry model with local minimum misfits is the one with dip angle linearly increasing along strike from 4.3oin top southernmost patch to 4.5oin top northernmost path and dip angle linearly increased. By using the fault shape and geodetic co-seismic data, we estimate the slip distribution on the curved fault. Our result shows that the earthquake ruptured *200-km width down to a depth of about 60 km.0.5–12.5 m of thrust slip is resolved with the largest slip centered around the central section of the rupture zone78N–108N in latitude. The estimated seismic moment is8.2 9 1022 N m, which is larger than estimation from the centroid moment magnitude(4.0 9 1022 N m), and smaller than estimation from normal-mode oscillation data modeling(1.0 9 1023 N m).
基金supported by National Natural Science Foundation of China(61963030).
文摘This paper proposes a high-efficiency PFC rectifier based on multiplexing the switches.Compared with a traditional six-switch PFC rectifier,the proposed rectifier extends the switches’active angle by making use of three bridge rectifiers.As a result,lower conduction resistance can be realized for switches.Consequently,system efficiency can be improved.Compared with a traditional six-switch PFC rectifier with doubled switches,the proposed rectifier can achieve almost the same efficiency improvement while no additional switches are needed.Since continuous inductor current is chopped and resulting current pulses cannot be injected into the grid directly,input filter design and resonance damping are discussed for the proposed rectifier.The controller design of the rectifier is analyzed.The inductor current reference is shaped considering the input voltage envelope and forward duties.Finally,the effectiveness of the proposed rectifier is verified through simulations and experiments.
基金supported by Natural Science Foundation of China(No.41674055)the Earthquake Science and Technology Spark Plan in Hebei Province(DZ20140101002)
文摘Stress field plays a key role in geodynamics. In this study, an algorithm to determine the stress tensor and its confidence range from focal mechanism data by using grid search method was proposed. The experiment uses artificial focal mechanism data which were generated by extensional, compression and strike-slip stress regime and different level of noise, shows that the precision of the estimated stress tensor based on this algorithm is greatly improved compared with traditional algorithms. This algorithm has three advantages:(1) The global optimal solution of the stress tensor is determined by fine grid search of 1o×1o×1o×0.01 and local minimum value is avoided; (2) precision of focal mechanism data can be considered, i.e., different weight of the focal mechanism data contributes differently to the process of determining stress tensor; (3) the confidence range of the determined stress tensor can be obtained by using F-test. We apply this algorithm in the boundary zone of China, Vietnam and Laos, and obtain the stress field with SSE-NNW compressive stress direction and NEE-SWW extensional stress direction. The stress ratio is 0.6, which shows that the eigen values of the stress tensor are nearly in arithmetic sequence. The stress field in this region is consistent with the left-lateral strike slip of the Dienbien-Lauangphrabang arc fault. The result will be helpful in studying the geological dynamic process in this region.