AIM:To reveal the functions of micro RNAs(mi RNAs) with respect to hepatic stellate cells(HSCs) in response to portal hypertension.METHODS:Primary rat HSCs were exposed to static water pressure(10 mm Hg,1 h) and the p...AIM:To reveal the functions of micro RNAs(mi RNAs) with respect to hepatic stellate cells(HSCs) in response to portal hypertension.METHODS:Primary rat HSCs were exposed to static water pressure(10 mm Hg,1 h) and the pressureinduced mi RNA expression profile was detected by next-generation sequencing. Quantitative real-time polymerase chain reaction was used to verify the expression of mi RNAs. A potential target of Mi R-9a-5p was measured by a luciferase reporter assay and Western blot. CCK-8 assay and Transwell assay were used to detect the proliferation and migration of HSCs under pressure.RESULTS:According to the profile,the expression of mi R-9a-5p was further confirmed to be significantly increased after pressure overload in HSCs(3.70 ± 0.61 vs 0.97 ± 0.15,P = 0.0226),which resulted in the proliferation,migration and activation of HSCs. In vivo,the up-regulation of mi R-9a-5p(2.09 ± 0.91 vs 4.27 ± 1.74,P = 0.0025) and the down-regulation of Sirt1(2.41 ± 0.51 vs 1.13 ± 0.11,P = 0.0006) were observed in rat fibrotic liver with portal hypertension. Sirt1 was a potential target gene of mi R-9a-5p. Through restoringthe expression of Sirt1 in mi R-9a-5p transfected HSCs on pressure overload,we found that overexpression of Sirt1 could partially abrogate the mi R-9a-5p mediated suppression of the proliferation,migration and activation of HSCs. CONCLUSION:Our results suggest that during liver fibrosis,portal hypertension may induce the proliferation,migration and activation of HSCs through the up-regulation of mi R-9a-5p,which targets Sirt1.展开更多
In this work, the field plate termination is studied for Ga2O3Schottky barrier diodes(SBDs) by simulation. The influence of field plate overlap, dielectric material and thickness on the termination electric field dist...In this work, the field plate termination is studied for Ga2O3Schottky barrier diodes(SBDs) by simulation. The influence of field plate overlap, dielectric material and thickness on the termination electric field distribution are demonstrated.It is found that the optimal thickness increases with reverse bias increasing for all the three dielectrics of SiO2, Al2O3, and HfO2. As the thickness increases, the maximum electric field intensity decreases in SiO2and Al2O3, but increases in HfO2.Furthermore, it is found that SiO2and HfO2are suitable for the 600 V rate Ga2O3SBD, and Al2O3is suitable for both600 V and 1200 V rate Ga2O3SBD. In addition, the comparison of Ga2O3SBDs between the SiC and GaN counterpart reveals that for Ga2O3, the breakdown voltage bottleneck is the dielectric. While, for SiC and GaN, the bottleneck is mainly the semiconductor itself.展开更多
A novel O2 plasma-based digital etching technology for p-GaN/AlGaN structures without any etch-stop layer was investigated using an inductively coupled plasma(ICP)etcher,with 100 W ICP power and 40 W rf bias power.Und...A novel O2 plasma-based digital etching technology for p-GaN/AlGaN structures without any etch-stop layer was investigated using an inductively coupled plasma(ICP)etcher,with 100 W ICP power and 40 W rf bias power.Under 40 sccm O2 flow and 3 min oxidation time,the p-GaN etch depth was 3.62 nm per circle.The surface roughness improved from 0.499 to 0.452 nm after digital etching,meaning that no observable damages were caused by this process.Compared to the dry etch only methods with Cl2/Ar/O2 or BCl3/SF6 plasma,this technique smoothed the surface and could efficiently control the etch depth due to its self-limiting characteristic.Furthermore,compared to other digital etching processes with an etch-stop layer,this approach was performed using ICP etcher and less demanding on the epitaxial growth.It was proved to be effective in precisely controlling p-GaN etch depth and surface damages required for high performance p-GaN gate high electron mobility transistors.展开更多
Thin-film flexible solar cells are lightweight and mechanically robust.Along with rapidly advancing battery technology,flexible solar panels are expected to create niche products that require lightweight,mechanical fl...Thin-film flexible solar cells are lightweight and mechanically robust.Along with rapidly advancing battery technology,flexible solar panels are expected to create niche products that require lightweight,mechanical flexibility,and moldability into complex shapes,such as roof-panel for electric automobiles,foldable umbrellas,camping tents,etc.In this paper,we provide a comprehensive assessment of relevant materials suitable for making flexible solar cells.Substrate materials reviewed include metals,ceramics,glasses,and plastics.For active materials,we focus primarily on emerging new semiconductors including small organic donor/acceptor molecules,conjugated donor/acceptor polymers,and organometal halide perovskites.For electrode materials,transparent conducting oxides,thin metal films/nanowires,nanocarbons,and conducting polymers are reviewed.We also discuss the merits,weaknesses,and future perspectives of these materials for developing next-generation flexible photovoltaics.展开更多
Solid H_(2)S as the precursor for H_(3)S with incredible superconducting properties under high pressure,has recently attracted extensive attention.Here in this work,we propose two new phases of H_(2)S with P42/n and I...Solid H_(2)S as the precursor for H_(3)S with incredible superconducting properties under high pressure,has recently attracted extensive attention.Here in this work,we propose two new phases of H_(2)S with P42/n and I41/a lattice symmetries in a pressure range of 0 GPa–30 GPa through first-principles structural searches,which complement the phase transition sequence.Further an ab initio molecular dynamics simulation confirms that the molecular phase P2/c of H_(2)S is gradually dissociated with the pressure increasing and reconstructs into a new P2_(1)/m structure at 160 GPa,exhibiting the superconductivity with Tc of 82.5 K.Our results may provide a guidance for the theoretical study of low-temperature superconducting phase of H_(2)S.展开更多
With technology computer-aided design(TCAD)simulation software,we design a new structure of gallium oxide on gallium-nitride Schottky barrier diode(SBD).The parameters of gallium oxide are defined as new material para...With technology computer-aided design(TCAD)simulation software,we design a new structure of gallium oxide on gallium-nitride Schottky barrier diode(SBD).The parameters of gallium oxide are defined as new material parameters in the material library,and the SBD turn-on and breakdown behavior are simulated.The simulation results reveal that this new structure has a larger turn-on current than Ga2O3 SBD and a larger breakdown voltage than Ga N SBD.Also,to solve the lattice mismatch problem in the real epitaxy,we add a Zn O layer as a transition layer.The simulations show that the device still has good properties after adding this layer.展开更多
Based on density functional theory calculations, it is found that for substitutional N in diamond the C3v symmetry structure is more stable, while C3v and D2d symmetry patterns for the substitutional P in diamond have...Based on density functional theory calculations, it is found that for substitutional N in diamond the C3v symmetry structure is more stable, while C3v and D2d symmetry patterns for the substitutional P in diamond have comparable energies. Moreover, the substitutional N is a deep donor for diamond, while P is a shallow substitutional n-type dopant. This is attributed to the different doping positions of dopant(the N atom is seriously deviated from the substitutional position, while the P atom nearly locates in the substitutional site), which are determined by the atomic radius.展开更多
The crystal structure,electronic structure,and superconductivity of copper hydrides at high pressure have been studied by ab initio calculation.Consistent with experimental report,results show that the predicted stoic...The crystal structure,electronic structure,and superconductivity of copper hydrides at high pressure have been studied by ab initio calculation.Consistent with experimental report,results show that the predicted stoichiometry Cu2H with the P-3m1 space group is stable above 16.8 GPa.The stoichiometry of CuH with the Fm-3m space group is predicted to be synthesized above 30 GPa,but it is metastable and dynamical instable up to 120 GPa.The electronic band calculations reveal that Cu2H is a good metal at a stable pressure range,whereas CuH is an insulator.Moreover,the other hydrogenrich compounds CuH2 and CuH3 are thermodynamically and dynamically unstable,respectively.The calculated superconducting transition temperature (Tc) of Cu2H at 40 GPa is 0.028 K by using the Allen-Dynes modified McMillan equation.展开更多
基金Supported by National Natural Science Foundation of China,No.11272342/A0205
文摘AIM:To reveal the functions of micro RNAs(mi RNAs) with respect to hepatic stellate cells(HSCs) in response to portal hypertension.METHODS:Primary rat HSCs were exposed to static water pressure(10 mm Hg,1 h) and the pressureinduced mi RNA expression profile was detected by next-generation sequencing. Quantitative real-time polymerase chain reaction was used to verify the expression of mi RNAs. A potential target of Mi R-9a-5p was measured by a luciferase reporter assay and Western blot. CCK-8 assay and Transwell assay were used to detect the proliferation and migration of HSCs under pressure.RESULTS:According to the profile,the expression of mi R-9a-5p was further confirmed to be significantly increased after pressure overload in HSCs(3.70 ± 0.61 vs 0.97 ± 0.15,P = 0.0226),which resulted in the proliferation,migration and activation of HSCs. In vivo,the up-regulation of mi R-9a-5p(2.09 ± 0.91 vs 4.27 ± 1.74,P = 0.0025) and the down-regulation of Sirt1(2.41 ± 0.51 vs 1.13 ± 0.11,P = 0.0006) were observed in rat fibrotic liver with portal hypertension. Sirt1 was a potential target gene of mi R-9a-5p. Through restoringthe expression of Sirt1 in mi R-9a-5p transfected HSCs on pressure overload,we found that overexpression of Sirt1 could partially abrogate the mi R-9a-5p mediated suppression of the proliferation,migration and activation of HSCs. CONCLUSION:Our results suggest that during liver fibrosis,portal hypertension may induce the proliferation,migration and activation of HSCs through the up-regulation of mi R-9a-5p,which targets Sirt1.
基金Project supported by the Research Fund of Low Cost Fabrication of GaN Power Devices and System Integration,China(Grant No.JCYJ20160226192639004)the Research Fund of AlGaN HEMT MEMS Sensor for Work in Extreme Environment,China(Grant No.JCYJ20170412153356899)the Research Fund of Reliability Mechanism and Circuit Simulation of GaN HEMT,China(Grant No.2017A050506002)
文摘In this work, the field plate termination is studied for Ga2O3Schottky barrier diodes(SBDs) by simulation. The influence of field plate overlap, dielectric material and thickness on the termination electric field distribution are demonstrated.It is found that the optimal thickness increases with reverse bias increasing for all the three dielectrics of SiO2, Al2O3, and HfO2. As the thickness increases, the maximum electric field intensity decreases in SiO2and Al2O3, but increases in HfO2.Furthermore, it is found that SiO2and HfO2are suitable for the 600 V rate Ga2O3SBD, and Al2O3is suitable for both600 V and 1200 V rate Ga2O3SBD. In addition, the comparison of Ga2O3SBDs between the SiC and GaN counterpart reveals that for Ga2O3, the breakdown voltage bottleneck is the dielectric. While, for SiC and GaN, the bottleneck is mainly the semiconductor itself.
基金Supported by the Guangdong Science and Technology Department(Grant Nos.2019B010128001 and 2019B010142001)the Shenzhen Municipal Council of Science and Innovation(Grant Nos.JCYJ20180305180619573 and JCYJ20170412153356899)the National Natural Science Foundation of China(Grant No.61704004)。
文摘A novel O2 plasma-based digital etching technology for p-GaN/AlGaN structures without any etch-stop layer was investigated using an inductively coupled plasma(ICP)etcher,with 100 W ICP power and 40 W rf bias power.Under 40 sccm O2 flow and 3 min oxidation time,the p-GaN etch depth was 3.62 nm per circle.The surface roughness improved from 0.499 to 0.452 nm after digital etching,meaning that no observable damages were caused by this process.Compared to the dry etch only methods with Cl2/Ar/O2 or BCl3/SF6 plasma,this technique smoothed the surface and could efficiently control the etch depth due to its self-limiting characteristic.Furthermore,compared to other digital etching processes with an etch-stop layer,this approach was performed using ICP etcher and less demanding on the epitaxial growth.It was proved to be effective in precisely controlling p-GaN etch depth and surface damages required for high performance p-GaN gate high electron mobility transistors.
基金Z.H.Lu would like to acknowledge the Natural Science and Engineering Research Council of Canada,and the National Natural Science Foundation of China(Grant No.11774304)for providing research fund.H.Y.Yu would like to acknowledge the financial support by Research and Application of Key Technologies of GaN-based Power Devices on Si Substrate(Grant No:2019B010128001)Research on key technologies for optimization of IoT chips and product development(Grant No.2019B010142001)+1 种基金and Study and optimization of electrostatic discharge mechanism for GaN HEMT devices(Grant No:JCYJ20180305180619573)Research of AlGaN HEMT MEMS sensor for work in extreme environment(Grant No:JCYJ20170412153356899).
文摘Thin-film flexible solar cells are lightweight and mechanically robust.Along with rapidly advancing battery technology,flexible solar panels are expected to create niche products that require lightweight,mechanical flexibility,and moldability into complex shapes,such as roof-panel for electric automobiles,foldable umbrellas,camping tents,etc.In this paper,we provide a comprehensive assessment of relevant materials suitable for making flexible solar cells.Substrate materials reviewed include metals,ceramics,glasses,and plastics.For active materials,we focus primarily on emerging new semiconductors including small organic donor/acceptor molecules,conjugated donor/acceptor polymers,and organometal halide perovskites.For electrode materials,transparent conducting oxides,thin metal films/nanowires,nanocarbons,and conducting polymers are reviewed.We also discuss the merits,weaknesses,and future perspectives of these materials for developing next-generation flexible photovoltaics.
基金the National Natural Science Foundation of China(Grant Nos.11704143,11804113,11604023,and 12122405)。
文摘Solid H_(2)S as the precursor for H_(3)S with incredible superconducting properties under high pressure,has recently attracted extensive attention.Here in this work,we propose two new phases of H_(2)S with P42/n and I41/a lattice symmetries in a pressure range of 0 GPa–30 GPa through first-principles structural searches,which complement the phase transition sequence.Further an ab initio molecular dynamics simulation confirms that the molecular phase P2/c of H_(2)S is gradually dissociated with the pressure increasing and reconstructs into a new P2_(1)/m structure at 160 GPa,exhibiting the superconductivity with Tc of 82.5 K.Our results may provide a guidance for the theoretical study of low-temperature superconducting phase of H_(2)S.
文摘With technology computer-aided design(TCAD)simulation software,we design a new structure of gallium oxide on gallium-nitride Schottky barrier diode(SBD).The parameters of gallium oxide are defined as new material parameters in the material library,and the SBD turn-on and breakdown behavior are simulated.The simulation results reveal that this new structure has a larger turn-on current than Ga2O3 SBD and a larger breakdown voltage than Ga N SBD.Also,to solve the lattice mismatch problem in the real epitaxy,we add a Zn O layer as a transition layer.The simulations show that the device still has good properties after adding this layer.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11704143,11604023,51672102,51972135,51632002,51572108,91745203 and 11634004the Program for Changjiang Scholars and Innovative Research Team in University under Grant No IRT_15R23
文摘Based on density functional theory calculations, it is found that for substitutional N in diamond the C3v symmetry structure is more stable, while C3v and D2d symmetry patterns for the substitutional P in diamond have comparable energies. Moreover, the substitutional N is a deep donor for diamond, while P is a shallow substitutional n-type dopant. This is attributed to the different doping positions of dopant(the N atom is seriously deviated from the substitutional position, while the P atom nearly locates in the substitutional site), which are determined by the atomic radius.
基金supported by the National Key R&D Program of China (Grant No. 2018YFA0305900)National Natural Science Foundation of China (Grant Nos.51632002,11674122,51572108,11634004,11504127,11574109,11704143, and 11404134)+4 种基金Program for Changjiang Scholars and Innovative Research Team in University (No.IRT15R23)the 111 Project (Grant No.B12011)Jilin Provincial Science and Technology Development Project of China (Grant No.20170520116JH)the National Found for Fostering Talents of basic Science (Grant No.J1103202)Parts of calculations were performed in the High Performance Computing Center (HPCC) of Jilin University and TianHe-1(A) at the National Supercomputer Center in Tianjin.
文摘The crystal structure,electronic structure,and superconductivity of copper hydrides at high pressure have been studied by ab initio calculation.Consistent with experimental report,results show that the predicted stoichiometry Cu2H with the P-3m1 space group is stable above 16.8 GPa.The stoichiometry of CuH with the Fm-3m space group is predicted to be synthesized above 30 GPa,but it is metastable and dynamical instable up to 120 GPa.The electronic band calculations reveal that Cu2H is a good metal at a stable pressure range,whereas CuH is an insulator.Moreover,the other hydrogenrich compounds CuH2 and CuH3 are thermodynamically and dynamically unstable,respectively.The calculated superconducting transition temperature (Tc) of Cu2H at 40 GPa is 0.028 K by using the Allen-Dynes modified McMillan equation.
