Development of magnetohydrodynamic acceleration technology is expected to improve wind tunnel simulation capability and testing capability.The underlying premise is to produce uniform and stable plasma in supersonic a...Development of magnetohydrodynamic acceleration technology is expected to improve wind tunnel simulation capability and testing capability.The underlying premise is to produce uniform and stable plasma in supersonic air flow,and gas discharge is an effective way to achieve this.A nanosecond pulsed discharge experimental system under supersonic conditions was established,and a pin-to-plate nanosecond pulsed discharge experiment in Mach 2 air flow was performed to verify that the proposed method produced uniform and stable plasma under supersonic conditions.The results show that the discharge under supersonic conditions was stable overall,but uniformity was not as good as that under static conditions.Increasing the number of pins improved discharge uniformity,but reduced discharge intensity and hence plasma density.Under multi-pin conditions at 1000Hz,the discharge was almost completely corona discharge,with the main current component being the displacement current,which was smaller than that under static conditions.展开更多
Apurine/pyrimidine-free endonuclease 1(APEX1)is a multifunctional enzyme that contributes to oxidization-mediated DNA-cleaved base excision repair and redox activation of transcription factors.However,the role of APEX...Apurine/pyrimidine-free endonuclease 1(APEX1)is a multifunctional enzyme that contributes to oxidization-mediated DNA-cleaved base excision repair and redox activation of transcription factors.However,the role of APEX1 during cardiomyocyte oxidative stress injury is not completely understood.In the present study,whether APEX1 protects oxidative damage-induced cardiomyocytes was investigated.mRNA and protein expression levels of APEX1 were downregulated in the mouse model of cardiac ischemia-reperfusion injury.Furthermore,the expression of APEX1 in hydrogen peroxide(H 2 O 2)-treated neonatal mice cardiomyocytes was also decreased.APEX1 knockdown aggravated H 2 O 2-treated cardiomyocyte apoptosis indexes.By contrast,APEX1 overexpression reversed H 2 O 2-induced oxidative damage,as demonstrated by decreased caspase 3 and Bax expression levels.Moreover,homeobox A5 upregulated APEX1.The results of the present study indicated that APEX1 displayed protective effects against oxidative damage,suggesting that APEX1 may serve as a unique protective strategy for cardiac ischemia-reperfusion injury.展开更多
A Dielectric Barrier Discharge(DBD) plasma actuator can create a body force which locally accelerates the base flow leading to an attenuation of broadband disturbance to delay the transition. In this study, numerical ...A Dielectric Barrier Discharge(DBD) plasma actuator can create a body force which locally accelerates the base flow leading to an attenuation of broadband disturbance to delay the transition. In this study, numerical simulation on an NLF0416 airfoil is conducted to investigate transition delay and drag reduction by a DBD plasma actuator. To simulate plasma’s effect more accurately, boundary-layer data is acquired from Reynolds Averaged Navier Stocks(RANS) equations instead of laminar boundary layer equations, although RANS equations need a much finer boundary-layer grid, and the linear stability analysis method is used to analyze the boundary layer and get the transition point. In this study, the influences of different actuation intensities and positions are investigated, and results show that if the actuation intensity is stronger and the actuation position is closer to the base transition point, more drag reduction can be obtained. However, the efficiency of plasma transition delay is really low. For example, when the actuation voltage is 16 k V,the actuation frequency is 1 k Hz, and the main Mach number is 0.1, the saved power due to drag reduction is about 5.09 W, but the power consumed is about 32.61 W, and the efficiency is just15.6%.展开更多
Aerogels are predominantly mesoporous,extremely lightweight,low density(∼0.003 g/cm 3)and thermally insulat-ing materials.Over the years,aerogels have gained increasing attention due to their extraordinary properties...Aerogels are predominantly mesoporous,extremely lightweight,low density(∼0.003 g/cm 3)and thermally insulat-ing materials.Over the years,aerogels have gained increasing attention due to their extraordinary properties(light,heat,sound,electricity and force)and application potentials in varieties of fields.Several studies have been carried out regarding aerogel preparation and its applications in coatings on different substrates.In this review,an overview of aerogels preparation and their application progress in coatings of most common substrates is presented.Attention is paid to aerogel coatings of textiles,leather,and substrates other than leather and textiles for special functionali-ties that could address the application progress in coatings.This review will help to inspire scientists and engineers towards novel aerogel materials and technologies to boost the industrial fabrication of flexible advanced materials.展开更多
基金National Natural Science Foundation of China (Nos. 11372352, 51776222)the China Postdoctoral Science Foundation (Nos. 2017T100772, 2016M590972).
文摘Development of magnetohydrodynamic acceleration technology is expected to improve wind tunnel simulation capability and testing capability.The underlying premise is to produce uniform and stable plasma in supersonic air flow,and gas discharge is an effective way to achieve this.A nanosecond pulsed discharge experimental system under supersonic conditions was established,and a pin-to-plate nanosecond pulsed discharge experiment in Mach 2 air flow was performed to verify that the proposed method produced uniform and stable plasma under supersonic conditions.The results show that the discharge under supersonic conditions was stable overall,but uniformity was not as good as that under static conditions.Increasing the number of pins improved discharge uniformity,but reduced discharge intensity and hence plasma density.Under multi-pin conditions at 1000Hz,the discharge was almost completely corona discharge,with the main current component being the displacement current,which was smaller than that under static conditions.
基金supported by the National Natural Science Foundation of China(Grant No.81900245 and 81770395).
文摘Apurine/pyrimidine-free endonuclease 1(APEX1)is a multifunctional enzyme that contributes to oxidization-mediated DNA-cleaved base excision repair and redox activation of transcription factors.However,the role of APEX1 during cardiomyocyte oxidative stress injury is not completely understood.In the present study,whether APEX1 protects oxidative damage-induced cardiomyocytes was investigated.mRNA and protein expression levels of APEX1 were downregulated in the mouse model of cardiac ischemia-reperfusion injury.Furthermore,the expression of APEX1 in hydrogen peroxide(H 2 O 2)-treated neonatal mice cardiomyocytes was also decreased.APEX1 knockdown aggravated H 2 O 2-treated cardiomyocyte apoptosis indexes.By contrast,APEX1 overexpression reversed H 2 O 2-induced oxidative damage,as demonstrated by decreased caspase 3 and Bax expression levels.Moreover,homeobox A5 upregulated APEX1.The results of the present study indicated that APEX1 displayed protective effects against oxidative damage,suggesting that APEX1 may serve as a unique protective strategy for cardiac ischemia-reperfusion injury.
基金supported by the National Numerical Wind Tunnel Project (No. NNW2018-ZT3B08)。
文摘A Dielectric Barrier Discharge(DBD) plasma actuator can create a body force which locally accelerates the base flow leading to an attenuation of broadband disturbance to delay the transition. In this study, numerical simulation on an NLF0416 airfoil is conducted to investigate transition delay and drag reduction by a DBD plasma actuator. To simulate plasma’s effect more accurately, boundary-layer data is acquired from Reynolds Averaged Navier Stocks(RANS) equations instead of laminar boundary layer equations, although RANS equations need a much finer boundary-layer grid, and the linear stability analysis method is used to analyze the boundary layer and get the transition point. In this study, the influences of different actuation intensities and positions are investigated, and results show that if the actuation intensity is stronger and the actuation position is closer to the base transition point, more drag reduction can be obtained. However, the efficiency of plasma transition delay is really low. For example, when the actuation voltage is 16 k V,the actuation frequency is 1 k Hz, and the main Mach number is 0.1, the saved power due to drag reduction is about 5.09 W, but the power consumed is about 32.61 W, and the efficiency is just15.6%.
基金This work was financially supported by the National Foreign Experts Program-Foreign Youth Talent Program(QN20200173001)the National Key R&D Pro-gram(2020YFE0203800)the Research and development project of China Leather and Footwear Research Institute Co.Ltd.(2021PGX02).
文摘Aerogels are predominantly mesoporous,extremely lightweight,low density(∼0.003 g/cm 3)and thermally insulat-ing materials.Over the years,aerogels have gained increasing attention due to their extraordinary properties(light,heat,sound,electricity and force)and application potentials in varieties of fields.Several studies have been carried out regarding aerogel preparation and its applications in coatings on different substrates.In this review,an overview of aerogels preparation and their application progress in coatings of most common substrates is presented.Attention is paid to aerogel coatings of textiles,leather,and substrates other than leather and textiles for special functionali-ties that could address the application progress in coatings.This review will help to inspire scientists and engineers towards novel aerogel materials and technologies to boost the industrial fabrication of flexible advanced materials.
