Objective:In this study,we used HepG2 human hepatocellular carcinoma cells to study the effects of Compound Xishu Granule(CXG)on cell proliferation,apoptosis,and the cell cycle in vitro.We also used a xenograft tumor ...Objective:In this study,we used HepG2 human hepatocellular carcinoma cells to study the effects of Compound Xishu Granule(CXG)on cell proliferation,apoptosis,and the cell cycle in vitro.We also used a xenograft tumor model to study the anti-tumor effects of CXG and related mechanisms in vivo.Methods:The effect of CXG on cell viability was measured using Cell Counting Kit-8 and a colony formation assay.The effect of CXG on apoptosis and the cell cycle was analyzed using flow cytometry.The in vivo anti-tumor effect of CXG was assessed by measuring the volume change in xenograft tumors after drug administration.The CXG anti-tumor mechanism was studied using western blotting assay to detect cell cycle and apoptotic associated proteins.Results:CXG suppressed HepG2 cell proliferation in a time-and dose-dependent manner in vitro.Colony formation experiments showed that CXG administration for 24 h significantly reduced HepG2 cell formations(P<.01).Flow cytometric analysis showed that CXG treatment for 48 h promoted apoptosis and blocked HepG2 cells in the G2/M phase.Western blotting results showed that Bax was significantly upregulated and Bcl-2 was down-regulated in graft tumor tissues and HepG2 cells after CXG administration,which increased the Bax/Bcl-2 ratio.PLK1,CDC25 C,CDK1,and Cyclin B1 expression were upregulated.CXG had a good inhibitory effect on graft tumor growth in vivo.Conclusion:CXG has good anti-tumor effects in vitro and in vivo.In vitro,CXG promoted HepG2 cell apoptosis and induced G2/M phase arrest.In vivo,CXG significantly inhibited graft tumor growth.The CXG mechanism in treating hepatocellular carcinoma may be that CXG can induce abnormal apoptotic and cell cycle associated protein expression,leading to mitotic catastrophe and apoptosis.展开更多
Aerogel fibers, distinguished by their lightweight nature, pronounced porosity, large surface area, and superior thermal insulation properties, have diversified applications in thermal management, energy devices, and ...Aerogel fibers, distinguished by their lightweight nature, pronounced porosity, large surface area, and superior thermal insulation properties, have diversified applications in thermal management, energy devices, and environmental remediation[1]. However, compared with monolithic ones, these fibershaped aerogels exhibit limited mechanical strength and resilience due to their one-dimensional small size.展开更多
Atmospheric reanalysis reproduces the past atmospheric conditions through assimilation of historical meteorological observations with fixed version of a numerical weather prediction(NWP)model and data assimilation(DA)...Atmospheric reanalysis reproduces the past atmospheric conditions through assimilation of historical meteorological observations with fixed version of a numerical weather prediction(NWP)model and data assimilation(DA)system.It is widely used in weather,climate,and even business-related research and applications.This paper reports the development of CMA’s first-generation global atmospheric reanalysis(RA)covering 1979–2018(CRA-40;CRA refers to CMA-RA).CRA-40 is produced by using the Global Spectral Model(GSM)/Gridpoint Statistical Interpolation(GSI)at a 6-h time interval and a TL574 spectral(34-km)resolution with the model top at 0.27 hPa.A large number of reprocessed satellite data and widely collected conventional observations were assimilated during the reanalyzing process,including the reprocessed atmospheric motion vector(AMV)products from FY-2C/D/E/G satellites,dense conventional observations(at about 120 radiosonde and 2400 synoptic stations)over China,as well as MWHS-2 and GNSS-RO observations from FY-3C.The reanalysis fitting to observations is improved over time,especially for surface pressure with root-mean-square error reduced from 1.05 hPa in 1979 to 0.8 hPa,and for upper air temperature from 1.65 K in 1979 to 1.35 K,in 2018.The patterns of global analysis increments for temperature,specific humidity,and zonal wind are consistent with the changes in the observing system.Near surface temperature from the model’s 6-h forecast reflects the global warming trend reasonably.The CRA-40 precipitation pattern matches well with those of GPCP and other reanalyses.CRA-40 also successfully captures the QBO and its vertical and temporal development,hemispherical atmospheric circulation change,and moisture transport by the East Asian summer monsoon.CRA is now operationally running in near real time as a climate data assimilation system in CMA.展开更多
Hydrophilic interaction liquid chromatography(HILIC) has been recognized as an effective strategy for glycopeptide enrichment. Hydrophilic materials pave the way to solve the limit of low enrichment capacity and poor ...Hydrophilic interaction liquid chromatography(HILIC) has been recognized as an effective strategy for glycopeptide enrichment. Hydrophilic materials pave the way to solve the limit of low enrichment capacity and poor selectivity. The present study is the first attempt to combine chitosan(CS) and L-cysteine(L-Cys) to design a novel hydrophilic material focusing on glycopeptide enrichment. CS containing a large number of hydrophilic amino and hydroxyl groups has unique chemical properties, which makes it a very attractive biomaterial for glycopeptide enrichment. The excellent hydrophilicity of zwitterionic molecule L-Cys inspires the idea of anchoring L-Cys onto CS to design a novel hydrophilic material(named as Fe_(3)O_(4)@CS@Au-L-Cys) for the capture of low abundance glycopeptides. To be specific, Au nanoparticles(Au NPs) was introduced into CS-coated Fe_(3)O_(4)via electrostatic interaction and served as bridges to anchor L-Cys onto the surface of CS through strong Au-S bond interaction. The prepared Fe_(3)O_(4)@CS@AuL-Cys exhibited strong affinity, low detection limit(0.5 fmol/μL HRP), high selectivity(HRP/BSA with a molar ratio of 1:1000) for glycopeptides. Moreover, successful application of glycopeptide enrichment in human serum and saliva by Fe_(3)O_(4)@CS@Au-L-Cys was achieved. A satisfactory data set indicates that Fe_(3)O_(4)@CS@Au-L-Cys has promising potential in the application of glycopeptide enrichment in real complex bio-samples and for related glycoproteome research.展开更多
The China Meteorological Administration(CMA)has recently developed a new global monthly homogenized land-surface air temperature data set.Based on this data set,we reanalyzed the change in global annual mean land-surf...The China Meteorological Administration(CMA)has recently developed a new global monthly homogenized land-surface air temperature data set.Based on this data set,we reanalyzed the change in global annual mean land-surface air temperature(LSAT)during three time periods(1901–2014,1979–2014 and 1998–2014).The results show that the linear trends of global annual mean LSAT were 0.104°C/decade,0.247°C/decade and 0.098°C/decade for the three periods,respectively.The trends were statistically significant except for the period 1998–2014,the period that展开更多
β-Ga2O3 MOSFETs are demonstrated on heterogeneous Ga2O3-Al2O3-Si(GaOISi)substrate fabricated by ion-cutting process.Enhancement(E)-and depletion(D)-modeβ-Ga2O3 transistors are realized on by varying the channel thic...β-Ga2O3 MOSFETs are demonstrated on heterogeneous Ga2O3-Al2O3-Si(GaOISi)substrate fabricated by ion-cutting process.Enhancement(E)-and depletion(D)-modeβ-Ga2O3 transistors are realized on by varying the channel thickness(Tch).E-mode GaOISi transistor with a Tchof 15 nm achieves a high threshold voltage VTHof^8 V.With the same T increase,GaOISi transistors demonstrate more stable ON-current IONand OFF-current IOFFperformance compared to the reported devices on bulk Ga2O3 wafer.Transistors on GaOISi achieve the breakdown voltage of 522 and 391 V at 25°C and 200°C,respectively.展开更多
We developed an integrated global land surface dataset(IGLD)at the National Meteorological Information Center of China Meteorological Administration.The IGLD consists of hourly data for 75 variables from five data sou...We developed an integrated global land surface dataset(IGLD)at the National Meteorological Information Center of China Meteorological Administration.The IGLD consists of hourly data for 75 variables from five data sources.It contains not only the most widely used variables(e.g.,pressure,temperature,dew-point temperature,and precipitation),but also visibility,cloud cover,snow depth,and so on.A hierarchy of data sources was created to identify duplicate records.The records located higher in the hierarchy were adopted preferentially in the IGLD.A comprehensive quality control procedure including extreme value test,internal consistency check,and spatiotemporal consistency check,was applied to the IGLD.The IGLD consists of land surface observations at more than 20,000 global sites from 1901 to 2018,of which about 17,000 stations are currently active.The number of global observatories generally increased over time,except for the 1960 s to 1970 s.It increased from about 2300 in 1951 to 17,000 in 2018.The observations over America,Europe,and eastern Asia always showed a high temporal integrity and dense spatial coverage,whereas measurements were sparser in South America,Africa,Russia,and the Mediterranean regions.In general,the standard and intermediate standard times for observation suggested by the World Meteorological Organization(WMO)were followed globally,except in Australia,where there were few data measured on the WMO schedule.The IGLD has been used in the China’s first generation global atmospheric reanalysis product(CRA)and the global daily precipitation dataset.展开更多
It has long been a great challenge to prepare materials with integrated merits of high strength,high modulus,high toughness,and light weight for structural material applications(e.g.,aircrafts,automobiles).High streng...It has long been a great challenge to prepare materials with integrated merits of high strength,high modulus,high toughness,and light weight for structural material applications(e.g.,aircrafts,automobiles).High strength representing a good resistance to deformation usually requires the material have a rigid/hard molecular structure,whereas high toughness representing a good resistance to fracture typically originates from a soft/flexible molecular structure.Therefore,the trade-off between the rigid and flexible components in a molecule usually leads to an intrinsic conflict between high strength and high toughness[1].It is more intuitively in the typical stressstrain curves,where the integrated area of a tensile curve can be calculated for the toughness.Apparently,the attainment of high toughness needs not only high strength but also high tensile strain.展开更多
Based on the ground surface temperature(GST)and snow surface temperature(SST)measurements during the period of adjustment from manual to automatic observation systems in China,the influence of observation methods on G...Based on the ground surface temperature(GST)and snow surface temperature(SST)measurements during the period of adjustment from manual to automatic observation systems in China,the influence of observation methods on GST and its relationship with snow cover is analyzed.GST is corrected by SST,and the correction effect is evaluated.The results show that,during the parallel observation period,the winter GSTs from automatic observations are generally higher than those from manual observations,with the automatically observed national daily GST 1.18°C higher.The adjustment has a greater impact on GSTs at 0200,0800,and 2000 Beijing Time(BT)than at 1400 BT,and it has the greatest impact in Northeast and Northwest China,with deviations of 5.24 and 2.09°C,respectively.The GST deviation is closely related to the snow depth and annual snow totals.The average daily GST deviation increases at the rate of 0.66°C per 1-cm increase of snow depth when it is<15 cm,while it tends to be stable at around 10°C for snow depth over 15 cm.The GST deviation at a station is affected by its winter snow totals in Northeast and Northwest China,where the largest deviations are found where snow totals are all above 1000 cm.After the correction with SST,the mean deviation between the automatic and manual observations as well as the false trend can be effectively reduced.Following the correction,the mean deviation of daily GST decreases by 5.8°C,and its trend decreases from 1.87 to 0.65°C decade-1.展开更多
The semiconductor,β-Ga_(2)O_(3)is attractive for applications in high power electronic devices with low conduction loss due to its ultra-wide bandgap(∼4.9 eV)and large Baliga’s figure of merit.However,the thermal c...The semiconductor,β-Ga_(2)O_(3)is attractive for applications in high power electronic devices with low conduction loss due to its ultra-wide bandgap(∼4.9 eV)and large Baliga’s figure of merit.However,the thermal conductivity of𝛽β-Ga_(2)O_(3)is much lower than that of other wide/ultra-wide bandgap semiconductors,such as SiC and GaN,which results in the deterioration of𝛽β-Ga_(2)O_(3)-based device performance and reliability due to self-heating.To overcome this problem,a scalable thermal management strategy was proposed by heterogeneously integrating wafer-scale single-crystalline𝛽β-Ga_(2)O_(3)thin films on a highly thermally conductive SiC substrate.Characterization of the transferred𝛽β-Ga_(2)O_(3)thin film indicated a uniform thickness to within±2.01%,a smooth surface with a roughness of 0.2 nm,and good crystalline quality with an X-ray rocking curves(XRC)full width at half maximum of 80 arcsec.Transient thermoreflectance measurements were employed to investigate the thermal properties.The thermal performance of the fabricated𝛽β-Ga_(2)O_(3)/SiC heterostructure was effectively improved in comparison with that of the𝛽β-Ga_(2)O_(3)bulk wafer,and the effective thermal boundary resistance could be further reduced to 7.5 m 2 K/GW by a post-annealing process.Schottky barrier diodes(SBDs)were fabricated on both a𝛽β-Ga_(2)O_(3)/SiC heterostructured material and a𝛽β-Ga_(2)O_(3)bulk wafer.Infrared thermal imaging revealed the temperature increase of the SBDs on𝛽β-Ga_(2)O_(3)/SiC to be one quarter that on the𝛽β-Ga_(2)O_(3)bulk wafer with the same applied power,which suggests that the combination of the𝛽-Ga_(2)O_(3)thin film and SiC substrate with high thermal conductivity promotes heat dissipation in𝛽β-Ga_(2)O_(3)-based devices.展开更多
基金Superiority Discipling Construction Project of Jiangsu Province:Nursing[2018](87)Special Project of Philosophy and Social Science Development of Nanjing Medical University(2019ZSZ003).
基金the Major Innovative Drug Development Project from Ministry of Science and Technology of the People’s Republic of China(Project No.2017ZX09301011)。
文摘Objective:In this study,we used HepG2 human hepatocellular carcinoma cells to study the effects of Compound Xishu Granule(CXG)on cell proliferation,apoptosis,and the cell cycle in vitro.We also used a xenograft tumor model to study the anti-tumor effects of CXG and related mechanisms in vivo.Methods:The effect of CXG on cell viability was measured using Cell Counting Kit-8 and a colony formation assay.The effect of CXG on apoptosis and the cell cycle was analyzed using flow cytometry.The in vivo anti-tumor effect of CXG was assessed by measuring the volume change in xenograft tumors after drug administration.The CXG anti-tumor mechanism was studied using western blotting assay to detect cell cycle and apoptotic associated proteins.Results:CXG suppressed HepG2 cell proliferation in a time-and dose-dependent manner in vitro.Colony formation experiments showed that CXG administration for 24 h significantly reduced HepG2 cell formations(P<.01).Flow cytometric analysis showed that CXG treatment for 48 h promoted apoptosis and blocked HepG2 cells in the G2/M phase.Western blotting results showed that Bax was significantly upregulated and Bcl-2 was down-regulated in graft tumor tissues and HepG2 cells after CXG administration,which increased the Bax/Bcl-2 ratio.PLK1,CDC25 C,CDK1,and Cyclin B1 expression were upregulated.CXG had a good inhibitory effect on graft tumor growth in vivo.Conclusion:CXG has good anti-tumor effects in vitro and in vivo.In vitro,CXG promoted HepG2 cell apoptosis and induced G2/M phase arrest.In vivo,CXG significantly inhibited graft tumor growth.The CXG mechanism in treating hepatocellular carcinoma may be that CXG can induce abnormal apoptotic and cell cycle associated protein expression,leading to mitotic catastrophe and apoptosis.
文摘Aerogel fibers, distinguished by their lightweight nature, pronounced porosity, large surface area, and superior thermal insulation properties, have diversified applications in thermal management, energy devices, and environmental remediation[1]. However, compared with monolithic ones, these fibershaped aerogels exhibit limited mechanical strength and resilience due to their one-dimensional small size.
基金Supported by the China Meteorological Administration Special Public Welfare Research Fund(GYHY201506002)National Innovation Project for Meteorological Science and Technology(CMAGGTD003-5).
文摘Atmospheric reanalysis reproduces the past atmospheric conditions through assimilation of historical meteorological observations with fixed version of a numerical weather prediction(NWP)model and data assimilation(DA)system.It is widely used in weather,climate,and even business-related research and applications.This paper reports the development of CMA’s first-generation global atmospheric reanalysis(RA)covering 1979–2018(CRA-40;CRA refers to CMA-RA).CRA-40 is produced by using the Global Spectral Model(GSM)/Gridpoint Statistical Interpolation(GSI)at a 6-h time interval and a TL574 spectral(34-km)resolution with the model top at 0.27 hPa.A large number of reprocessed satellite data and widely collected conventional observations were assimilated during the reanalyzing process,including the reprocessed atmospheric motion vector(AMV)products from FY-2C/D/E/G satellites,dense conventional observations(at about 120 radiosonde and 2400 synoptic stations)over China,as well as MWHS-2 and GNSS-RO observations from FY-3C.The reanalysis fitting to observations is improved over time,especially for surface pressure with root-mean-square error reduced from 1.05 hPa in 1979 to 0.8 hPa,and for upper air temperature from 1.65 K in 1979 to 1.35 K,in 2018.The patterns of global analysis increments for temperature,specific humidity,and zonal wind are consistent with the changes in the observing system.Near surface temperature from the model’s 6-h forecast reflects the global warming trend reasonably.The CRA-40 precipitation pattern matches well with those of GPCP and other reanalyses.CRA-40 also successfully captures the QBO and its vertical and temporal development,hemispherical atmospheric circulation change,and moisture transport by the East Asian summer monsoon.CRA is now operationally running in near real time as a climate data assimilation system in CMA.
基金supported by the National Natural Science Foundation of China(61874128 and 62174167)the Frontier Science Key Program of CAS(QYZDY-SSW-JSC032 and ZDBS-LY-JSC009)+2 种基金the Program of Shanghai Academic Research Leader(19XD1404600)K.C.Wong Education Foundation(GJTD-2019-11)the Key Research Project of Zhejiang Laboratory(2021MD0AC01)。
基金financially supported by Open Project of State Key Laboratory of Supramolecular Structure and Materials,Jilin University,China(No.sklssm2022012)the Fundamental Research Funds for the Central Universities,JLU,China。
文摘Hydrophilic interaction liquid chromatography(HILIC) has been recognized as an effective strategy for glycopeptide enrichment. Hydrophilic materials pave the way to solve the limit of low enrichment capacity and poor selectivity. The present study is the first attempt to combine chitosan(CS) and L-cysteine(L-Cys) to design a novel hydrophilic material focusing on glycopeptide enrichment. CS containing a large number of hydrophilic amino and hydroxyl groups has unique chemical properties, which makes it a very attractive biomaterial for glycopeptide enrichment. The excellent hydrophilicity of zwitterionic molecule L-Cys inspires the idea of anchoring L-Cys onto CS to design a novel hydrophilic material(named as Fe_(3)O_(4)@CS@Au-L-Cys) for the capture of low abundance glycopeptides. To be specific, Au nanoparticles(Au NPs) was introduced into CS-coated Fe_(3)O_(4)via electrostatic interaction and served as bridges to anchor L-Cys onto the surface of CS through strong Au-S bond interaction. The prepared Fe_(3)O_(4)@CS@AuL-Cys exhibited strong affinity, low detection limit(0.5 fmol/μL HRP), high selectivity(HRP/BSA with a molar ratio of 1:1000) for glycopeptides. Moreover, successful application of glycopeptide enrichment in human serum and saliva by Fe_(3)O_(4)@CS@Au-L-Cys was achieved. A satisfactory data set indicates that Fe_(3)O_(4)@CS@Au-L-Cys has promising potential in the application of glycopeptide enrichment in real complex bio-samples and for related glycoproteome research.
基金financially supported by the National Natural Science Foundation of China(41575003)the Special Research Program for Public Welfare(Meteorology)of China(GYHY201206012)
文摘The China Meteorological Administration(CMA)has recently developed a new global monthly homogenized land-surface air temperature data set.Based on this data set,we reanalyzed the change in global annual mean land-surface air temperature(LSAT)during three time periods(1901–2014,1979–2014 and 1998–2014).The results show that the linear trends of global annual mean LSAT were 0.104°C/decade,0.247°C/decade and 0.098°C/decade for the three periods,respectively.The trends were statistically significant except for the period 1998–2014,the period that
基金the National Key Research and Development Project(Grant No.2018YFB2200500)the National Natural Science Foundation of China(Grant Nos.61851406,61874128,11622545,61534004,61604112,and 61622405)+1 种基金the Frontier Science Key Program of Chinese Academy of Sciences(Grant No.QYZDY-SSW-JSC032)the Shanghai Municipal Science and Technology Commission(Grant No.18511110503)。
文摘β-Ga2O3 MOSFETs are demonstrated on heterogeneous Ga2O3-Al2O3-Si(GaOISi)substrate fabricated by ion-cutting process.Enhancement(E)-and depletion(D)-modeβ-Ga2O3 transistors are realized on by varying the channel thickness(Tch).E-mode GaOISi transistor with a Tchof 15 nm achieves a high threshold voltage VTHof^8 V.With the same T increase,GaOISi transistors demonstrate more stable ON-current IONand OFF-current IOFFperformance compared to the reported devices on bulk Ga2O3 wafer.Transistors on GaOISi achieve the breakdown voltage of 522 and 391 V at 25°C and 200°C,respectively.
基金Supported by the National Natural Science Foundation of China(41805128)National Key Research and Development Program of China(2017YFC1501801)+1 种基金National Natural Science Foundation of China(42093190043)National Innovation Project for Meteorological Science and Technology(CMAGGTD003-5)。
文摘We developed an integrated global land surface dataset(IGLD)at the National Meteorological Information Center of China Meteorological Administration.The IGLD consists of hourly data for 75 variables from five data sources.It contains not only the most widely used variables(e.g.,pressure,temperature,dew-point temperature,and precipitation),but also visibility,cloud cover,snow depth,and so on.A hierarchy of data sources was created to identify duplicate records.The records located higher in the hierarchy were adopted preferentially in the IGLD.A comprehensive quality control procedure including extreme value test,internal consistency check,and spatiotemporal consistency check,was applied to the IGLD.The IGLD consists of land surface observations at more than 20,000 global sites from 1901 to 2018,of which about 17,000 stations are currently active.The number of global observatories generally increased over time,except for the 1960 s to 1970 s.It increased from about 2300 in 1951 to 17,000 in 2018.The observations over America,Europe,and eastern Asia always showed a high temporal integrity and dense spatial coverage,whereas measurements were sparser in South America,Africa,Russia,and the Mediterranean regions.In general,the standard and intermediate standard times for observation suggested by the World Meteorological Organization(WMO)were followed globally,except in Australia,where there were few data measured on the WMO schedule.The IGLD has been used in the China’s first generation global atmospheric reanalysis product(CRA)and the global daily precipitation dataset.
文摘It has long been a great challenge to prepare materials with integrated merits of high strength,high modulus,high toughness,and light weight for structural material applications(e.g.,aircrafts,automobiles).High strength representing a good resistance to deformation usually requires the material have a rigid/hard molecular structure,whereas high toughness representing a good resistance to fracture typically originates from a soft/flexible molecular structure.Therefore,the trade-off between the rigid and flexible components in a molecule usually leads to an intrinsic conflict between high strength and high toughness[1].It is more intuitively in the typical stressstrain curves,where the integrated area of a tensile curve can be calculated for the toughness.Apparently,the attainment of high toughness needs not only high strength but also high tensile strain.
基金Supported by the Climate Change Special Fund of the China Meteorological Administration(CCSF201919,CCSF201910,and CCSF202013)Natural Foundation Guidance Plan of Liaoning Province(2019-ZD-0859)National Key Research and Development Program of China(2017YFC1501801)。
文摘Based on the ground surface temperature(GST)and snow surface temperature(SST)measurements during the period of adjustment from manual to automatic observation systems in China,the influence of observation methods on GST and its relationship with snow cover is analyzed.GST is corrected by SST,and the correction effect is evaluated.The results show that,during the parallel observation period,the winter GSTs from automatic observations are generally higher than those from manual observations,with the automatically observed national daily GST 1.18°C higher.The adjustment has a greater impact on GSTs at 0200,0800,and 2000 Beijing Time(BT)than at 1400 BT,and it has the greatest impact in Northeast and Northwest China,with deviations of 5.24 and 2.09°C,respectively.The GST deviation is closely related to the snow depth and annual snow totals.The average daily GST deviation increases at the rate of 0.66°C per 1-cm increase of snow depth when it is<15 cm,while it tends to be stable at around 10°C for snow depth over 15 cm.The GST deviation at a station is affected by its winter snow totals in Northeast and Northwest China,where the largest deviations are found where snow totals are all above 1000 cm.After the correction with SST,the mean deviation between the automatic and manual observations as well as the false trend can be effectively reduced.Following the correction,the mean deviation of daily GST decreases by 5.8°C,and its trend decreases from 1.87 to 0.65°C decade-1.
基金supported by the funding from National Natural Science Foundation of China(Grants No.61851406,61874128,and U1732268)Frontier Science Key Program of CAS(Grant No.QYZDY-SSWJSC032)+2 种基金Program of Shanghai Academic Research Leader(Grant No.19XD1404600)K.C.Wong Education Foundation(Grant No.GJTD-2019-11)Shenzhen Science and Technology Innovation Program(Grant No.JCYJ20190806142614541).
文摘The semiconductor,β-Ga_(2)O_(3)is attractive for applications in high power electronic devices with low conduction loss due to its ultra-wide bandgap(∼4.9 eV)and large Baliga’s figure of merit.However,the thermal conductivity of𝛽β-Ga_(2)O_(3)is much lower than that of other wide/ultra-wide bandgap semiconductors,such as SiC and GaN,which results in the deterioration of𝛽β-Ga_(2)O_(3)-based device performance and reliability due to self-heating.To overcome this problem,a scalable thermal management strategy was proposed by heterogeneously integrating wafer-scale single-crystalline𝛽β-Ga_(2)O_(3)thin films on a highly thermally conductive SiC substrate.Characterization of the transferred𝛽β-Ga_(2)O_(3)thin film indicated a uniform thickness to within±2.01%,a smooth surface with a roughness of 0.2 nm,and good crystalline quality with an X-ray rocking curves(XRC)full width at half maximum of 80 arcsec.Transient thermoreflectance measurements were employed to investigate the thermal properties.The thermal performance of the fabricated𝛽β-Ga_(2)O_(3)/SiC heterostructure was effectively improved in comparison with that of the𝛽β-Ga_(2)O_(3)bulk wafer,and the effective thermal boundary resistance could be further reduced to 7.5 m 2 K/GW by a post-annealing process.Schottky barrier diodes(SBDs)were fabricated on both a𝛽β-Ga_(2)O_(3)/SiC heterostructured material and a𝛽β-Ga_(2)O_(3)bulk wafer.Infrared thermal imaging revealed the temperature increase of the SBDs on𝛽β-Ga_(2)O_(3)/SiC to be one quarter that on the𝛽β-Ga_(2)O_(3)bulk wafer with the same applied power,which suggests that the combination of the𝛽-Ga_(2)O_(3)thin film and SiC substrate with high thermal conductivity promotes heat dissipation in𝛽β-Ga_(2)O_(3)-based devices.
