A three-dimensional(3D)silicon-carbide(SiC)trench metal-oxide-semiconductor field-effect transistor(MOSFET)with a heterojunction diode(HJD-TMOS)is proposed and studied in this work.The SiC MOSFET is characterized by a...A three-dimensional(3D)silicon-carbide(SiC)trench metal-oxide-semiconductor field-effect transistor(MOSFET)with a heterojunction diode(HJD-TMOS)is proposed and studied in this work.The SiC MOSFET is characterized by an HJD which is partially embedded on one side of the gate.When the device is in the turn-on state,the body parasitic diode can be effectively controlled by the embedded HJD,the switching loss thus decreases for the device.Moreover,a highly-doped P+layer is encircled the gate oxide on the same side as the HJD and under the gate oxide,which is used to lighten the electric field concentration and improve the reliability of gate oxide layer.Physical mechanism for the HJD-TMOS is analyzed.Comparing with the conventional device with the same level of on-resistance,the breakdown voltage of the HJD-TMOS is improved by 23.4%,and the miller charge and the switching loss decrease by 43.2%and 48.6%,respectively.展开更多
The Global Influenza Surveillance Network is crucial for monitoring epidemic risk in participating countries. However, at present, the network has notable gaps in the developing world, principally in Africa and Asia w...The Global Influenza Surveillance Network is crucial for monitoring epidemic risk in participating countries. However, at present, the network has notable gaps in the developing world, principally in Africa and Asia where laboratory capabilities are limited. Moreover, for the last few years, various influenza viruses have been continuously emerging in the resource-limited countries, making these surveillance gaps a more imminent challenge.We present a spatial-transmission model to estimate epidemic risks in the countries where only partial or even no surveillance data are available. Motivated by the observation that countries in the same influenza transmission zone divided by the World Health Organization had similar transmission patterns, we propose to estimate the influenza epidemic risk of an unmonitored country by incorporating the surveillance data reported by countries of the same transmission zone. Experiments show that the risk estimates are highly correlated with the actual influenza morbidity trends for African and Asian countries. The proposed method may provide the much-needed capability to detect, assess, and notify potential influenza epidemics to the developing world.展开更多
基金the Natural Science Foundation Project of Chongqing Science and Technology Commission,China(Grant No.cstc2020jcyj-msxmX0243)the Fundamental Research Funds for the Central Universities,China(Grant No.2020CDJ-LHZZ-024)the Chongqing Technology Innovation and Application Development Key Project,China(Grant No.cstc2019jscx-zdztzxX0051).
文摘A three-dimensional(3D)silicon-carbide(SiC)trench metal-oxide-semiconductor field-effect transistor(MOSFET)with a heterojunction diode(HJD-TMOS)is proposed and studied in this work.The SiC MOSFET is characterized by an HJD which is partially embedded on one side of the gate.When the device is in the turn-on state,the body parasitic diode can be effectively controlled by the embedded HJD,the switching loss thus decreases for the device.Moreover,a highly-doped P+layer is encircled the gate oxide on the same side as the HJD and under the gate oxide,which is used to lighten the electric field concentration and improve the reliability of gate oxide layer.Physical mechanism for the HJD-TMOS is analyzed.Comparing with the conventional device with the same level of on-resistance,the breakdown voltage of the HJD-TMOS is improved by 23.4%,and the miller charge and the switching loss decrease by 43.2%and 48.6%,respectively.
基金Project supported by the National Natural Science Foundation of China(Nos.61103212 and 61471073)the Chinese Post-Doctoral Science Foundation(Nos.2012M521678 and 2013T60836)
文摘The Global Influenza Surveillance Network is crucial for monitoring epidemic risk in participating countries. However, at present, the network has notable gaps in the developing world, principally in Africa and Asia where laboratory capabilities are limited. Moreover, for the last few years, various influenza viruses have been continuously emerging in the resource-limited countries, making these surveillance gaps a more imminent challenge.We present a spatial-transmission model to estimate epidemic risks in the countries where only partial or even no surveillance data are available. Motivated by the observation that countries in the same influenza transmission zone divided by the World Health Organization had similar transmission patterns, we propose to estimate the influenza epidemic risk of an unmonitored country by incorporating the surveillance data reported by countries of the same transmission zone. Experiments show that the risk estimates are highly correlated with the actual influenza morbidity trends for African and Asian countries. The proposed method may provide the much-needed capability to detect, assess, and notify potential influenza epidemics to the developing world.
