基于量子化学密度泛函理论和过渡态理论研究了含酮基团对煤焦异相还原NO的影响及其产物发生氧脱附的微观反应机理。计算结果表明,NO更易于吸附在含酮基团煤焦表面。椅形含酮基团强化了煤焦异相还原NO;锯齿形含酮煤焦表面与NO异相反应决...基于量子化学密度泛函理论和过渡态理论研究了含酮基团对煤焦异相还原NO的影响及其产物发生氧脱附的微观反应机理。计算结果表明,NO更易于吸附在含酮基团煤焦表面。椅形含酮基团强化了煤焦异相还原NO;锯齿形含酮煤焦表面与NO异相反应决速步能垒值(495.45 k J/mol)大于锯齿形纯碳基煤焦表面与NO决速步能垒值(331.32 k J/mol),基于锯齿形含酮煤焦模型中的氧浓度不在利于NO还原的范围内而不易于NO的还原。中间产物P1在无CO存在情况下,较纯碳基煤焦表面更易于发生氧脱附而产生表面缺陷;在CO存在条件下,含酮煤焦表面为氧脱附过程提供自由活性位点,降低了过程能垒消耗。展开更多
The ABCDE model has been described comprehensively to interpret the mechanism of floral organ development. In Arabidopsis, AGMAOUS was a well-studied class C gene encoding a transcription factor with MADS box, and its...The ABCDE model has been described comprehensively to interpret the mechanism of floral organ development. In Arabidopsis, AGMAOUS was a well-studied class C gene encoding a transcription factor with MADS box, and its overexpression in Arabidopsis induced the transformation of sepals to carpels and petals to stamens. However, there is little knowledge about the function of OsMADS58, which was a homologue of AGMAOUS in rice. In our study, OsMADS58 driven by the UBIQUITIN promoter was ectopiely expressed in Arabidopsis., and carpel-like sepals, incomplete petals and stamens instead of petals were found in different transgenie plants according to different OsMADS58 mRNA expression levels. The phenotype of transgenic plant was similar to the AGMAOUS overexpression plant, suggesting that OsMADS58 might play an important role in flower development like AGMAOUS and they keep conserved function during evolution.展开更多
The forward current transport mechanism and Schottky barrier characteristics of a Ni/Au contact on n-GaN are studied by using temperature-dependent current-voltage(T–I–V)and capacitance-voltage(C–V)measurements.The...The forward current transport mechanism and Schottky barrier characteristics of a Ni/Au contact on n-GaN are studied by using temperature-dependent current-voltage(T–I–V)and capacitance-voltage(C–V)measurements.The low-forward-bias I–V curve of the Schottky junction is found to be dominated by trap-assisted tunneling below 400 K,and thus can not be used to deduce the Schottky barrier height(SBH)based on the thermionic emission(TE)model.On the other hand,TE transport mechanism dominates the high-forward-bias region and a modified I–V method is adopted to deduce the effective barrier height.It is found that the estimated SBH(~0.95 eV at 300 K)by the I–V method is~0.20 eV lower than that obtained by the C–V method,which is explained by a barrier inhomogeneity model over the Schottky contact area.展开更多
ZnO films are grown on c-sapphire substrates by laser molecular beam epitaxy.The band offsets of the ZnO/Al_(2)O_(3) heterojunction are studied by in situ x-ray photoelectron spectroscopy.The valence band of Al_(2)O_(...ZnO films are grown on c-sapphire substrates by laser molecular beam epitaxy.The band offsets of the ZnO/Al_(2)O_(3) heterojunction are studied by in situ x-ray photoelectron spectroscopy.The valence band of Al_(2)O_(3) is found to be 3.59±0.05 eV below that of ZnO.Together with the resulting conduction band offset of 2.04±0.05 eV,this indicates that a type-I staggered band line exists at the ZnO/Al_(2)O_(3) heterojunction.展开更多
基金Supported by the National Key R&D Program of China Grant No.2021YFC2203102 and 2022YFF0503404by the National Natural Science Foundation of China Grants No.12173036,11773024+1 种基金by the China Manned Space Project Grant No.CMS-CSST-2021-B01by the Fundamental Research Funds for Central Universities Grants No.WK3440000004 and WK3440000005.
文摘基于量子化学密度泛函理论和过渡态理论研究了含酮基团对煤焦异相还原NO的影响及其产物发生氧脱附的微观反应机理。计算结果表明,NO更易于吸附在含酮基团煤焦表面。椅形含酮基团强化了煤焦异相还原NO;锯齿形含酮煤焦表面与NO异相反应决速步能垒值(495.45 k J/mol)大于锯齿形纯碳基煤焦表面与NO决速步能垒值(331.32 k J/mol),基于锯齿形含酮煤焦模型中的氧浓度不在利于NO还原的范围内而不易于NO的还原。中间产物P1在无CO存在情况下,较纯碳基煤焦表面更易于发生氧脱附而产生表面缺陷;在CO存在条件下,含酮煤焦表面为氧脱附过程提供自由活性位点,降低了过程能垒消耗。
基金Supported by the National Natural Science Foundation of China (31070265)the Natural Science Foundation of Shanghai (10ZR1434800)
文摘The ABCDE model has been described comprehensively to interpret the mechanism of floral organ development. In Arabidopsis, AGMAOUS was a well-studied class C gene encoding a transcription factor with MADS box, and its overexpression in Arabidopsis induced the transformation of sepals to carpels and petals to stamens. However, there is little knowledge about the function of OsMADS58, which was a homologue of AGMAOUS in rice. In our study, OsMADS58 driven by the UBIQUITIN promoter was ectopiely expressed in Arabidopsis., and carpel-like sepals, incomplete petals and stamens instead of petals were found in different transgenie plants according to different OsMADS58 mRNA expression levels. The phenotype of transgenic plant was similar to the AGMAOUS overexpression plant, suggesting that OsMADS58 might play an important role in flower development like AGMAOUS and they keep conserved function during evolution.
基金Supported by the National Basic Research Program of China under Grant No 2010CB327504the National Natural Science Foundation of China under Grant Nos 60936004 and 11074280+1 种基金the Fundamental Research Funds for the Central Universities of China under Grant Nos JUSRP111A42,JUSRP211A37 and JUSRP20914the State Key Laboratory of ASIC&System under Grant No 11KF003.
文摘The forward current transport mechanism and Schottky barrier characteristics of a Ni/Au contact on n-GaN are studied by using temperature-dependent current-voltage(T–I–V)and capacitance-voltage(C–V)measurements.The low-forward-bias I–V curve of the Schottky junction is found to be dominated by trap-assisted tunneling below 400 K,and thus can not be used to deduce the Schottky barrier height(SBH)based on the thermionic emission(TE)model.On the other hand,TE transport mechanism dominates the high-forward-bias region and a modified I–V method is adopted to deduce the effective barrier height.It is found that the estimated SBH(~0.95 eV at 300 K)by the I–V method is~0.20 eV lower than that obtained by the C–V method,which is explained by a barrier inhomogeneity model over the Schottky contact area.
基金Supported by the Major Instrumentation Special of the Ministry of Science and Technology of China under Grant No 2011YQ130018Open Foundation of Joint Laboratory for Extreme Conditions Matter Properties,Southwest University of Sci-ence and Technology and Research Center of Laser Fusion,CAEP(No 12zxjk06)the National High-Technology Research and Development Program of China.
文摘ZnO films are grown on c-sapphire substrates by laser molecular beam epitaxy.The band offsets of the ZnO/Al_(2)O_(3) heterojunction are studied by in situ x-ray photoelectron spectroscopy.The valence band of Al_(2)O_(3) is found to be 3.59±0.05 eV below that of ZnO.Together with the resulting conduction band offset of 2.04±0.05 eV,this indicates that a type-I staggered band line exists at the ZnO/Al_(2)O_(3) heterojunction.
