To find the highlighted advantage and development space of plateau characteristic agriculture in Yunnan,using qualitative and quantitative combining methods,comparative advantage of plateau characteristic agriculture ...To find the highlighted advantage and development space of plateau characteristic agriculture in Yunnan,using qualitative and quantitative combining methods,comparative advantage of plateau characteristic agriculture in Yunnan is evaluated comprehensively.Qualitation takes Sichuan,Chongqing,Guizhou and Guangxi adjacent to Yunnan and Southeast Asian countries which are opening focus of " bridgehead" as reference objects,while quantitation takes 32 provinces of whole country except Hongkong and Macao as reference objects,and there are 4 kinds of qualitation indexes and 6 kinds of quantitation indexes containing 44 sub-items.Results show that comprehensive comparative advantage coefficient of plateau characteristic agriculture in Yunnan is 1.55,and it has 3 kinds of comprehensive comparative advantages:diversity,ecological security and time difference complementation.The research results could provide references for agricultural development in Yunnan and other plateau regions.展开更多
Direct-current transfer characteristics of (InGaN)/A1GaN/A1N/GaN heterojunction field effect transistors (HFETs) are presented. A drain current plateau (IDs = 32.0 mA/mm) for Vcs swept from +0.7 V to -0. 6 V is...Direct-current transfer characteristics of (InGaN)/A1GaN/A1N/GaN heterojunction field effect transistors (HFETs) are presented. A drain current plateau (IDs = 32.0 mA/mm) for Vcs swept from +0.7 V to -0. 6 V is present in the transfer characteristics of InGaN/AIGaN/AIN/GaN HFETs. The theoretical calculation shows the coexistence of two-dimensional electron gas (2DEG) and two-dimensional hole gas (2DHG) in InGaN/AIGaN/A1N/GaN heterostructures, and the screening effect of 2DHG to the 2DEG in the conduction channel can explain this current plateau. Moreover, the current plateau shows the time-dependent behavior when IDs Vcs scans repeated are conducted. The obtained insight provides indication for the design in the fabrication of GaN-based super HFETs.展开更多
The diagnostic model of the cumulus convection proposed by Yanai et al. (1973) was applied to the atmosphere over the Tibetan Plateau, and used to estimate the vertical mass flux, entrainment and detrainment, excess t...The diagnostic model of the cumulus convection proposed by Yanai et al. (1973) was applied to the atmosphere over the Tibetan Plateau, and used to estimate the vertical mass flux, entrainment and detrainment, excess temperature and moisture, liquid water content, and condensation and precipitation rates of highland cloud clusters. The results illustrated that in clouds over the Tibetan Plateau, the water vapor condensation rate, liquid water content, and efficiency of the rain generation process are less than those in the tropics (represented by the Marshall Islands region). Therefore, the condensational latent heat released over the Tibetan Plateau, overall, is much smaller than that in the tropics. The water vapor and liquid water detrainment from shallow nonprecipitating cumulus clouds, and their entrainment into deep cumulus clouds, serve as a growing mechanism for the deep precipitating cumulus towers over the Tibetan Plateau. It should be noted that there is a stronger detrainment of liquid water from cumulus clouds and a stronger re-evaporation rate in environment. The process of the condensation-detrainment-re-evaporation-cnlrainmcnt is repeatedly in progress. It would play an important role in maintaining of cumulus convection on the condition that the supply of moisture is not plentiful over the Tibetan Plateau.The analyses also showed that the cloud mass flux Mc over the Tibetan Plateau is less, and the large-scale average upward motion is much less than those over the Marshall Islands. Stronger compensating downward motion in the cloud environment over the Tibetan Plateau, responsible for the area's strong environmental heating rate Was revealed, and would link to the stability of the South Asian High in summer.展开更多
The prototype neutron flux monitor consists of a high purity 235U fission chamber detector and a 'blank' detector, which is a fissile material free detector with the same dimension as the fission chamber detec...The prototype neutron flux monitor consists of a high purity 235U fission chamber detector and a 'blank' detector, which is a fissile material free detector with the same dimension as the fission chamber detector to identify noise issues such as noise coming from gamma rays. The main parameters of the fission chamber assembly that have been measured in the laboratory are confirmed to approach the technological level of the International Thermonuclear Experimental Reactor (ITER) in the near future. This prototype neutron flux monitor will be further developed to become a neutron flux monitor suitable for the operation phase of D-D fusion on the ITER.展开更多
基金Supported by Excellent Team Building and Advanced Scientific Research of Yunnan Academy of Agricultural Sciences(2014CZYY014)
文摘To find the highlighted advantage and development space of plateau characteristic agriculture in Yunnan,using qualitative and quantitative combining methods,comparative advantage of plateau characteristic agriculture in Yunnan is evaluated comprehensively.Qualitation takes Sichuan,Chongqing,Guizhou and Guangxi adjacent to Yunnan and Southeast Asian countries which are opening focus of " bridgehead" as reference objects,while quantitation takes 32 provinces of whole country except Hongkong and Macao as reference objects,and there are 4 kinds of qualitation indexes and 6 kinds of quantitation indexes containing 44 sub-items.Results show that comprehensive comparative advantage coefficient of plateau characteristic agriculture in Yunnan is 1.55,and it has 3 kinds of comprehensive comparative advantages:diversity,ecological security and time difference complementation.The research results could provide references for agricultural development in Yunnan and other plateau regions.
基金Supported by the Knowledge Innovation Project of the Chinese Academy of Sciencesthe National Natural Science Foundation of China under Grant Nos 61204017 and 61334002+1 种基金the National Basic Research Program of Chinathe National Science and Technology Major Project of China
文摘Direct-current transfer characteristics of (InGaN)/A1GaN/A1N/GaN heterojunction field effect transistors (HFETs) are presented. A drain current plateau (IDs = 32.0 mA/mm) for Vcs swept from +0.7 V to -0. 6 V is present in the transfer characteristics of InGaN/AIGaN/AIN/GaN HFETs. The theoretical calculation shows the coexistence of two-dimensional electron gas (2DEG) and two-dimensional hole gas (2DHG) in InGaN/AIGaN/A1N/GaN heterostructures, and the screening effect of 2DHG to the 2DEG in the conduction channel can explain this current plateau. Moreover, the current plateau shows the time-dependent behavior when IDs Vcs scans repeated are conducted. The obtained insight provides indication for the design in the fabrication of GaN-based super HFETs.
文摘The diagnostic model of the cumulus convection proposed by Yanai et al. (1973) was applied to the atmosphere over the Tibetan Plateau, and used to estimate the vertical mass flux, entrainment and detrainment, excess temperature and moisture, liquid water content, and condensation and precipitation rates of highland cloud clusters. The results illustrated that in clouds over the Tibetan Plateau, the water vapor condensation rate, liquid water content, and efficiency of the rain generation process are less than those in the tropics (represented by the Marshall Islands region). Therefore, the condensational latent heat released over the Tibetan Plateau, overall, is much smaller than that in the tropics. The water vapor and liquid water detrainment from shallow nonprecipitating cumulus clouds, and their entrainment into deep cumulus clouds, serve as a growing mechanism for the deep precipitating cumulus towers over the Tibetan Plateau. It should be noted that there is a stronger detrainment of liquid water from cumulus clouds and a stronger re-evaporation rate in environment. The process of the condensation-detrainment-re-evaporation-cnlrainmcnt is repeatedly in progress. It would play an important role in maintaining of cumulus convection on the condition that the supply of moisture is not plentiful over the Tibetan Plateau.The analyses also showed that the cloud mass flux Mc over the Tibetan Plateau is less, and the large-scale average upward motion is much less than those over the Marshall Islands. Stronger compensating downward motion in the cloud environment over the Tibetan Plateau, responsible for the area's strong environmental heating rate Was revealed, and would link to the stability of the South Asian High in summer.
基金The project supported by the National Natural Science Foundation of China (No.10175021)the Retraining Foundation of the Southwestern Institute of Physics for Talented Personnel
文摘The prototype neutron flux monitor consists of a high purity 235U fission chamber detector and a 'blank' detector, which is a fissile material free detector with the same dimension as the fission chamber detector to identify noise issues such as noise coming from gamma rays. The main parameters of the fission chamber assembly that have been measured in the laboratory are confirmed to approach the technological level of the International Thermonuclear Experimental Reactor (ITER) in the near future. This prototype neutron flux monitor will be further developed to become a neutron flux monitor suitable for the operation phase of D-D fusion on the ITER.