A new thiostannate,[tmdpH2]Sn3S7 1（tmdp = 4,4＇-trimethylenedipiperidine）,has been synthesized under solvothermal conditions and characterized by elemental analysis,IR spectroscopy,and single-crystal X-ray diffracti...A new thiostannate,[tmdpH2]Sn3S7 1（tmdp = 4,4＇-trimethylenedipiperidine）,has been synthesized under solvothermal conditions and characterized by elemental analysis,IR spectroscopy,and single-crystal X-ray diffraction analysis.In 1,the Sn3S4 secondary incomplete cubane-like building units are bridged by μ2-S atoms to form Sn12S12 rings which are then joined parallelly to the [001] plane,giving the final 2D（Sn3S7^2-）n layer of（6,3） network.The layers are stacked along the c axis so that 24-membered ring channels are generated,in which the organic cations are accommodated.The compound crystallizes in monoclinic,space group C2/c,with a=23.052（3）,b=13.4039（12）,c=18.412（2）A,β=120.112（4）°,V=4921.3（9）A^3,C13H28N2S7Sn3,Mr=792.86,Z=8,Dc=2.140 g/cm^3,F（000）=3056,μ=3.619 mm^-1,the final R=0.0488 and wR=0.1125 for 4607 observed reflections with I〉2σ（I）.展开更多
Three-dimensional(3D)carbon networks have been explored as promising capacitive materials thanks to their unique structural features such as large ion-accessible surface area and interconnected porous networks,thus en...Three-dimensional(3D)carbon networks have been explored as promising capacitive materials thanks to their unique structural features such as large ion-accessible surface area and interconnected porous networks,thus enhancing both ions and electrons transport.Here,sustainable bacterial cellulose(BC)is used both precursor and template for facile synthesis of free-standing N,S-codoped 3Dcarbon networks(a-NSC)by the pyrolysis and activation of polyrhodanine coated BC.The synthesized a-NSC shows highly conductive interconnected porous networks(24S·cm^(-1)),large surface area(1 420m^2·g^(-1))with hierarchical meso-microporosity,and high-level heteroatoms codoping(N:3.1%in atom,S:3.2%in atom).Benefitting from these,a-NSC as binder-free electrode exhibits an ultrahigh specific capacitance of 340F·g^(-1)(24μF·cm^(-2))at the current density of 0.5A·g^(-1)in 6MKOH electrolyte,high-rate capability(71%at 20A·g^(-1))and excellent cycle stability.Furthermore,the assembled symmetrical supercapacitor displays a much short time constant of 0.35sin 1MTEABF4/AN electrolyte,obtaining a maximum energy density of 32.1W·h·kg^(-1 )at power density of 637W·kg^(-1).The in situ multi-heteroatoms doping enables biocellulose-derived carbon networks to exploit its full potentials in energy storage applications,which can be extended to other dimensional carbon nanostructures.展开更多
Two parameterization schemes for vertical eddy diffusivity were utilized to investigate their impacts on both the daily and monthly mean concentrations of ozone and NOy, which are the major fractions of the sum of all...Two parameterization schemes for vertical eddy diffusivity were utilized to investigate their impacts on both the daily and monthly mean concentrations of ozone and NOy, which are the major fractions of the sum of all reactive nitrogen species, i.e., NOy=NO＋NO2＋HNO3＋PAN. Simulations indicate that great changes in the vertical diffusivity usually occur within the planetary boundary layer （PBL）. Daily and monthly mean concentrations of NOy are much more sensitive to changes in the vertical diffusivity than those of ozone and ozone and NOy levels only at or in （relatively） clean sites and areas, where long-range transport plays a crucial role, display roughly equivalent sensitivity. The results strongly suggest that a widely-accepted parameterization scheme be selected and the refinement of the model＇s vertical resolution in the PBL be required, even for regional and long-term studies, and ozone only being examined in an effort to judge the model＇s performance be unreliable, and NOy be included for model evaluations.展开更多
This paper discusses the effect of N2 plasma treatment before dielectric deposition on the electrical performance of a Al203/AlGaN/GaN metal-insulator-semiconductor high electron mobility transistor （MISHEMT）,with A...This paper discusses the effect of N2 plasma treatment before dielectric deposition on the electrical performance of a Al203/AlGaN/GaN metal-insulator-semiconductor high electron mobility transistor （MISHEMT）,with Al203 deposited by atomic layer deposition.The results indicated that the gate leakage was decreased two orders of magnitude after the Al203/AlGaN interface was pretreated by N2 plasma.Furthermore,effects of N2 plasma pretreatrnent on the electrical properties of the AlGaN/Al2O3 interface were investigated by x-ray photoelectron spectroscopy measurements and the interface quality between Al203 and AlGaN film was improved.展开更多
基金supported by the 973 Program (2007CB815301 and 2006CB932904)the National Natural Science Foundation of China (20333070, 20673118, 20871114)+1 种基金the Science Foundation of CAS (KJCX2-YW-M05)Fujian Province (2006L2005, 2006J0014, 2006F3132)
文摘A new thiostannate,[tmdpH2]Sn3S7 1（tmdp = 4,4＇-trimethylenedipiperidine）,has been synthesized under solvothermal conditions and characterized by elemental analysis,IR spectroscopy,and single-crystal X-ray diffraction analysis.In 1,the Sn3S4 secondary incomplete cubane-like building units are bridged by μ2-S atoms to form Sn12S12 rings which are then joined parallelly to the [001] plane,giving the final 2D（Sn3S7^2-）n layer of（6,3） network.The layers are stacked along the c axis so that 24-membered ring channels are generated,in which the organic cations are accommodated.The compound crystallizes in monoclinic,space group C2/c,with a=23.052（3）,b=13.4039（12）,c=18.412（2）A,β=120.112（4）°,V=4921.3（9）A^3,C13H28N2S7Sn3,Mr=792.86,Z=8,Dc=2.140 g/cm^3,F（000）=3056,μ=3.619 mm^-1,the final R=0.0488 and wR=0.1125 for 4607 observed reflections with I〉2σ（I）.
基金supported by the National Basic Research Program of China(973 Program)(No.2014CB239701)the National Natural Science Foundation of China(Nos.51672128,51372116,21773118)+2 种基金the Natural Science Foundation of Jiangsu Province(Nos.BK20150739,BK20151468)the Prospective Joint Research Project of Cooperative Innovation Fund of Jiangsu Province(No.BY2015003-7)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Three-dimensional(3D)carbon networks have been explored as promising capacitive materials thanks to their unique structural features such as large ion-accessible surface area and interconnected porous networks,thus enhancing both ions and electrons transport.Here,sustainable bacterial cellulose(BC)is used both precursor and template for facile synthesis of free-standing N,S-codoped 3Dcarbon networks(a-NSC)by the pyrolysis and activation of polyrhodanine coated BC.The synthesized a-NSC shows highly conductive interconnected porous networks(24S·cm^(-1)),large surface area(1 420m^2·g^(-1))with hierarchical meso-microporosity,and high-level heteroatoms codoping(N:3.1%in atom,S:3.2%in atom).Benefitting from these,a-NSC as binder-free electrode exhibits an ultrahigh specific capacitance of 340F·g^(-1)(24μF·cm^(-2))at the current density of 0.5A·g^(-1)in 6MKOH electrolyte,high-rate capability(71%at 20A·g^(-1))and excellent cycle stability.Furthermore,the assembled symmetrical supercapacitor displays a much short time constant of 0.35sin 1MTEABF4/AN electrolyte,obtaining a maximum energy density of 32.1W·h·kg^(-1 )at power density of 637W·kg^(-1).The in situ multi-heteroatoms doping enables biocellulose-derived carbon networks to exploit its full potentials in energy storage applications,which can be extended to other dimensional carbon nanostructures.
基金the National Natural Science Foundation of China （Grant No. 40575068） the National Key Project of Basic Research of China （Grant No. 2005CB422205） the Knowledge Innovation Project of Chinese Academy of Sciences （Grant No. KZCX2-YW-205）.
文摘Two parameterization schemes for vertical eddy diffusivity were utilized to investigate their impacts on both the daily and monthly mean concentrations of ozone and NOy, which are the major fractions of the sum of all reactive nitrogen species, i.e., NOy=NO＋NO2＋HNO3＋PAN. Simulations indicate that great changes in the vertical diffusivity usually occur within the planetary boundary layer （PBL）. Daily and monthly mean concentrations of NOy are much more sensitive to changes in the vertical diffusivity than those of ozone and ozone and NOy levels only at or in （relatively） clean sites and areas, where long-range transport plays a crucial role, display roughly equivalent sensitivity. The results strongly suggest that a widely-accepted parameterization scheme be selected and the refinement of the model＇s vertical resolution in the PBL be required, even for regional and long-term studies, and ozone only being examined in an effort to judge the model＇s performance be unreliable, and NOy be included for model evaluations.
基金Project supported by National Advanced Research Program (Grant No 51308030102)Xi’an Applied Materials Innovation Fund (Grant No XA-AM-200616)National Natural Science Foundation of China (Grant Nos 60506020 and 60676048)
文摘This paper discusses the effect of N2 plasma treatment before dielectric deposition on the electrical performance of a Al203/AlGaN/GaN metal-insulator-semiconductor high electron mobility transistor （MISHEMT）,with Al203 deposited by atomic layer deposition.The results indicated that the gate leakage was decreased two orders of magnitude after the Al203/AlGaN interface was pretreated by N2 plasma.Furthermore,effects of N2 plasma pretreatrnent on the electrical properties of the AlGaN/Al2O3 interface were investigated by x-ray photoelectron spectroscopy measurements and the interface quality between Al203 and AlGaN film was improved.
