It is discovered that the product of the current and the electric field in a PN junction should be regarded as the rate of work(power)done by the electric field force on moving charges(hole current and electron curren...It is discovered that the product of the current and the electric field in a PN junction should be regarded as the rate of work(power)done by the electric field force on moving charges(hole current and electron current),which was previously misinterpreted as solely a Joule heating effect.We clarify that it is exactly the work done by the electric field force on the moving charges to stimulate the emergence of non-equilibrium carriers,which triggers the novel physical phenomena.As regards to Joule heat,we point out that it should be calculated from Ohm’s law,rather than simply from the product of the current and the electric field.Based on this understanding,we conduct thorough discussion on the role of the electric field force in the process of carrier recombination and carrier generation.The thermal effects of carrier recombination and carrier generation followed are incorporated into the thermal equation of energy.The present study shows that the exothermic effect of carrier recombination leads to a temperature rise at the PN interface,while the endothermic effect of carrier generation causes a temperature reduction at the interface.These two opposite effects cause opposite heat flow directions in the PN junction under forward and backward bias voltages,highlighting the significance of managing device heating phenomena in design considerations.Therefore,this study possesses referential significance for the design and tuning on the performance of piezotronic devices.展开更多
Background:Outbreaks of coronavirus disease 2019(COVID-19)have been recorded in different countries across the globe.The virus is highly contagious,hence early detection,isolation,and quarantine of infected patients w...Background:Outbreaks of coronavirus disease 2019(COVID-19)have been recorded in different countries across the globe.The virus is highly contagious,hence early detection,isolation,and quarantine of infected patients will play an important role in containing the viral spread.Diagnosis in a mobile lab can aid to find infected patients in time.Methods:Here,we develop a field-deployable diagnostic workflow that can reliably detect COVID-19.Instruments used in this workflow can easily fit in a mobile cabin hospital and also be installed in the community.Different steps from sample inactivation to detection were optimized to find the fastest steps and portable instruments in the detection of COVID-19.Each step was compared to that of the normal laboratory diagnosis setup.Results:From the results,our proposed workflow(80 min)was two times faster compared to that of the normal laboratory workflow(183 min)and a maximum of 32 samples could be detected at each run.Additionally,we showed that using 1%Rewocid WK-30 could inactivate the novel coronavirus directly without affecting the overall detection results.Comparison of our workflow using an in-house assay to that of a commercially acquired assay produced highly reliable results.From the 250 hospital samples tested,there was a high concordance 247/250(98.8%)between the two assays.The in-house assay sensitivity and specificity were 116/116(100%)and 131/134(97.8%)compared to that of the commercial assay.Conclusion:Based on these results,we believe that our workflow is fast,reliable,adaptable and most importantly,field-deployable.展开更多
Propofol may produce memory impairment during anesthesia procedure. Local field potentials (LFPs) are used with increasing frequency in recent years to link neural activity to perception and cognition. In this study, ...Propofol may produce memory impairment during anesthesia procedure. Local field potentials (LFPs) are used with increasing frequency in recent years to link neural activity to perception and cognition. In this study, effect of propofol on LFPs in rat’s prefrontal cortex during working memory task was evaluated. Young (approximately 3 month) male Sprague-Dawley rats were divided into two group: propofol rats and control rats. Propofol rats received propofol at 0.9 mg/Kg·min intravenously for 2 h. After 12 h, LFPs of all rats were measured simultaneously from multiple electrodes placed in prefrontal cortex while rats were performing a working memory task in Y-maze. LFPs instantaneous phase were obtained by applying Hilbert transform, and cross-correlation coherence of LFPs was calculated. The results indicate that propofol decreased the correct rate and crosscorrelation coherence of LFPs on the first two days (p 0.05). Our results suggest that propofol can impair cross-correlation coherence of LFPs in the first two days, but not long time.展开更多
After graduating from the physics department of Qinghua University in 1952, I started working in the development of nuclear detectors (including cloud chambers and scintillometers) under the instruction of Profs. Yang...After graduating from the physics department of Qinghua University in 1952, I started working in the development of nuclear detectors (including cloud chambers and scintillometers) under the instruction of Profs. Yang Chengzhong and Dai Chuanzeng at the CAS Institute of Modern Physics.From 1956 to 1958,I studied at Lebedev’s Institute of Physics under the Soviet Academy展开更多
Since 1958. I bave been doing research and teaching work at Harbin Polytechnic on the theories of radar,navigational guidance,and signal processing & information treatment by developing new radar systems. In 1979,...Since 1958. I bave been doing research and teaching work at Harbin Polytechnic on the theories of radar,navigational guidance,and signal processing & information treatment by developing new radar systems. In 1979, I went to England in the status of an honorary research fellow and stayed there for two years.probing into HF radar systems under the guidance of the world-famous British marine telemetrist Professor Shearman at Birmingham University.Here.I briefly展开更多
I graduated from the National Peiyang University (now called Tianjin University) in 1950, majoring in hydraulic engineering. Starting from 1952, my teaching work was basically in mechanics.My first academic probe was ...I graduated from the National Peiyang University (now called Tianjin University) in 1950, majoring in hydraulic engineering. Starting from 1952, my teaching work was basically in mechanics.My first academic probe was in cybernetics, resulting in the publication of the first Chinese paper concerning optimal control. After 1963, I worked on the theory of hydrodynamic stability. My explorative thrust is at the eigenvalues of the Orr Sommerfeld Equation,a non-self adjoint problem in展开更多
International standards state the thermal comfort requirements that office spaces must comply with. These are based on a model developed by Prof. Paul Ole Fanger of the Centre for Indoor Environment and Energy, Denmar...International standards state the thermal comfort requirements that office spaces must comply with. These are based on a model developed by Prof. Paul Ole Fanger of the Centre for Indoor Environment and Energy, Denmark. Today, forty-year research shows an evolution in these experiences. The work presented here is to develop a tool to evaluate the thermal comfort of working environments of office buildings. A methodology is devised on the basis of on-site measurements and questionnaire responses. For measurements, a mobile unit equipped with sensors is used, whereas the questionnaire obtains user responses on thermal quality of the work space. The thermal conditions of thirty office buildings presenting different acclimatization systems have been surveyed. The correlation between objective and subjective data allows developing a formula that shows the thermal comfort level for a given environment as a function of local aspects. For the surveyed buildings, the resulting comfortable temperature was 23.3℃, and the minimum percentage of user individuals experiencing discomfort with such temperature was 7%.展开更多
基金the National Natural Science Foundation of China(Nos.12232007,11972164,and 12102141)。
文摘It is discovered that the product of the current and the electric field in a PN junction should be regarded as the rate of work(power)done by the electric field force on moving charges(hole current and electron current),which was previously misinterpreted as solely a Joule heating effect.We clarify that it is exactly the work done by the electric field force on the moving charges to stimulate the emergence of non-equilibrium carriers,which triggers the novel physical phenomena.As regards to Joule heat,we point out that it should be calculated from Ohm’s law,rather than simply from the product of the current and the electric field.Based on this understanding,we conduct thorough discussion on the role of the electric field force in the process of carrier recombination and carrier generation.The thermal effects of carrier recombination and carrier generation followed are incorporated into the thermal equation of energy.The present study shows that the exothermic effect of carrier recombination leads to a temperature rise at the PN interface,while the endothermic effect of carrier generation causes a temperature reduction at the interface.These two opposite effects cause opposite heat flow directions in the PN junction under forward and backward bias voltages,highlighting the significance of managing device heating phenomena in design considerations.Therefore,this study possesses referential significance for the design and tuning on the performance of piezotronic devices.
文摘Background:Outbreaks of coronavirus disease 2019(COVID-19)have been recorded in different countries across the globe.The virus is highly contagious,hence early detection,isolation,and quarantine of infected patients will play an important role in containing the viral spread.Diagnosis in a mobile lab can aid to find infected patients in time.Methods:Here,we develop a field-deployable diagnostic workflow that can reliably detect COVID-19.Instruments used in this workflow can easily fit in a mobile cabin hospital and also be installed in the community.Different steps from sample inactivation to detection were optimized to find the fastest steps and portable instruments in the detection of COVID-19.Each step was compared to that of the normal laboratory diagnosis setup.Results:From the results,our proposed workflow(80 min)was two times faster compared to that of the normal laboratory workflow(183 min)and a maximum of 32 samples could be detected at each run.Additionally,we showed that using 1%Rewocid WK-30 could inactivate the novel coronavirus directly without affecting the overall detection results.Comparison of our workflow using an in-house assay to that of a commercially acquired assay produced highly reliable results.From the 250 hospital samples tested,there was a high concordance 247/250(98.8%)between the two assays.The in-house assay sensitivity and specificity were 116/116(100%)and 131/134(97.8%)compared to that of the commercial assay.Conclusion:Based on these results,we believe that our workflow is fast,reliable,adaptable and most importantly,field-deployable.
文摘Propofol may produce memory impairment during anesthesia procedure. Local field potentials (LFPs) are used with increasing frequency in recent years to link neural activity to perception and cognition. In this study, effect of propofol on LFPs in rat’s prefrontal cortex during working memory task was evaluated. Young (approximately 3 month) male Sprague-Dawley rats were divided into two group: propofol rats and control rats. Propofol rats received propofol at 0.9 mg/Kg·min intravenously for 2 h. After 12 h, LFPs of all rats were measured simultaneously from multiple electrodes placed in prefrontal cortex while rats were performing a working memory task in Y-maze. LFPs instantaneous phase were obtained by applying Hilbert transform, and cross-correlation coherence of LFPs was calculated. The results indicate that propofol decreased the correct rate and crosscorrelation coherence of LFPs on the first two days (p 0.05). Our results suggest that propofol can impair cross-correlation coherence of LFPs in the first two days, but not long time.
文摘After graduating from the physics department of Qinghua University in 1952, I started working in the development of nuclear detectors (including cloud chambers and scintillometers) under the instruction of Profs. Yang Chengzhong and Dai Chuanzeng at the CAS Institute of Modern Physics.From 1956 to 1958,I studied at Lebedev’s Institute of Physics under the Soviet Academy
文摘Since 1958. I bave been doing research and teaching work at Harbin Polytechnic on the theories of radar,navigational guidance,and signal processing & information treatment by developing new radar systems. In 1979, I went to England in the status of an honorary research fellow and stayed there for two years.probing into HF radar systems under the guidance of the world-famous British marine telemetrist Professor Shearman at Birmingham University.Here.I briefly
文摘I graduated from the National Peiyang University (now called Tianjin University) in 1950, majoring in hydraulic engineering. Starting from 1952, my teaching work was basically in mechanics.My first academic probe was in cybernetics, resulting in the publication of the first Chinese paper concerning optimal control. After 1963, I worked on the theory of hydrodynamic stability. My explorative thrust is at the eigenvalues of the Orr Sommerfeld Equation,a non-self adjoint problem in
文摘International standards state the thermal comfort requirements that office spaces must comply with. These are based on a model developed by Prof. Paul Ole Fanger of the Centre for Indoor Environment and Energy, Denmark. Today, forty-year research shows an evolution in these experiences. The work presented here is to develop a tool to evaluate the thermal comfort of working environments of office buildings. A methodology is devised on the basis of on-site measurements and questionnaire responses. For measurements, a mobile unit equipped with sensors is used, whereas the questionnaire obtains user responses on thermal quality of the work space. The thermal conditions of thirty office buildings presenting different acclimatization systems have been surveyed. The correlation between objective and subjective data allows developing a formula that shows the thermal comfort level for a given environment as a function of local aspects. For the surveyed buildings, the resulting comfortable temperature was 23.3℃, and the minimum percentage of user individuals experiencing discomfort with such temperature was 7%.
