To enhance the separation selectivity of Mg-MOF-74 towards CO_(2) in a CO_(2)/N_(2) mixture,a series of Mg-MOF-74 and Ni_(x)/Mg_(1-x)-MOF-74 adsorbents were prepared by solvothermal synthesis in this paper.It was foun...To enhance the separation selectivity of Mg-MOF-74 towards CO_(2) in a CO_(2)/N_(2) mixture,a series of Mg-MOF-74 and Ni_(x)/Mg_(1-x)-MOF-74 adsorbents were prepared by solvothermal synthesis in this paper.It was found that the adsorption capacity of Mg-MOF-74 for CO_(2) could be effectively increased by optimizing the amount of acetic acid.On this basis,the bimetal MOF-74 adsorbent was prepared by metal modification.The multi-component dynamic adsorption penetration analysis was utilized to examine the CO_(2) adsorption capacity and CO_(2)/N_(2) selectivity of the diverse adsorbent materials.The results showed that Ni0.11/Mg0.89-MOF-74 showed a CO_(2) adsorption capacity of 7.02 mmol/g under pure CO_(2) atmosphere and had a selectivity of 20.50 for CO_(2)/N_(2) under 15% CO_(2)/85%N_(2) conditions,which was 10.2% and 18.02% higher than that of Mg-MOF-74 respectively.Combining XPS,SEM and N_(2) adsorption-desorption characterization analysis,it was attributed to the effect of the more stable unsaturated metal sites Ni into the Mg-MOF-74 on the pore structure and the synergistic interaction between the two metals.Density Functional Theory(DFT)simulations revealed that the synergistic interaction between modulated the electrostatic potential strength and gradient of the material,which was more favorable for the adsorption of CO_(2) molecules with small diameters and large quadrupole moment.In addition,the Ni0.11/Mg0.89-MOF-74 showed commendable cyclic stability,underscoring its promising potential for practical applications.展开更多
High quality GaN films on (0001) sapphire substrates were grown by a commercial MOCVD system (Thomas Swan Corp.).The etch pits and threading dislocations(TDs) in GaN films have been studied by chemical etching methods...High quality GaN films on (0001) sapphire substrates were grown by a commercial MOCVD system (Thomas Swan Corp.).The etch pits and threading dislocations(TDs) in GaN films have been studied by chemical etching methods such as mixed acid solution (H 3PO 4∶H 2SO 4=1∶3) and molten KOH,HCl vapor etching method,scanning electron microscope (SEM) and transmission electron microscope(TEM).SEM images of the same position of GaN films with HCl vapor etching and wet etching methods show notably different densities and shapes of etching pits.The results indicate that HCl vapor etching can show pure edge,pure screw and mixed TDs,mixed acid solution can show pure screw and mixed TDs and molten KOH wet etching only can show pure screw TDs.展开更多
A new structure IGBT is proposed for reducing the power dissipation.It features a composite voltage-sustaining layer which includes a n-type buffer layer formed by ultra-deep diffusion and a transparent backside emitt...A new structure IGBT is proposed for reducing the power dissipation.It features a composite voltage-sustaining layer which includes a n-type buffer layer formed by ultra-deep diffusion and a transparent backside emitter formed by boron implantation.Working in a deep punch-through state during its normal operating condition,it still possesses all the characteristics of the robust non-punch-through IGBT (NPT-IGBT).With a chip-thickness thinner than that of the NPT-IGBT,the new structure presents a better trade-off relationship between the on-state voltage-drop and the turn-off loss.Experimental results show that the power loss of the new structure IGBT is 40% lower than that of the NPT-IGBT.展开更多
基金supported by National Natural Science Foundation of China(U23A20100)the Strategic Priority Research Program(A)of the Chinese Academy of Sciences(XDA0390404)+5 种基金ICC CAS SCJC-DT-2023-03,the Foundation of State Key Laboratory of Coal Conversion(J24-25-619)Youth Innovation Promotion Association CAS(2018209,2020179)Key R&D Program of Shanxi Province(202102090301008,202202090301013)the special fund for S&T Innovation Team of Shanxi Province(202204051001012)Project of International Cooperation and Exchange NSFC-RFBR(22011530069)Tianjin Science and Technology Plan Project(22YFYSHZ00290)。
文摘To enhance the separation selectivity of Mg-MOF-74 towards CO_(2) in a CO_(2)/N_(2) mixture,a series of Mg-MOF-74 and Ni_(x)/Mg_(1-x)-MOF-74 adsorbents were prepared by solvothermal synthesis in this paper.It was found that the adsorption capacity of Mg-MOF-74 for CO_(2) could be effectively increased by optimizing the amount of acetic acid.On this basis,the bimetal MOF-74 adsorbent was prepared by metal modification.The multi-component dynamic adsorption penetration analysis was utilized to examine the CO_(2) adsorption capacity and CO_(2)/N_(2) selectivity of the diverse adsorbent materials.The results showed that Ni0.11/Mg0.89-MOF-74 showed a CO_(2) adsorption capacity of 7.02 mmol/g under pure CO_(2) atmosphere and had a selectivity of 20.50 for CO_(2)/N_(2) under 15% CO_(2)/85%N_(2) conditions,which was 10.2% and 18.02% higher than that of Mg-MOF-74 respectively.Combining XPS,SEM and N_(2) adsorption-desorption characterization analysis,it was attributed to the effect of the more stable unsaturated metal sites Ni into the Mg-MOF-74 on the pore structure and the synergistic interaction between the two metals.Density Functional Theory(DFT)simulations revealed that the synergistic interaction between modulated the electrostatic potential strength and gradient of the material,which was more favorable for the adsorption of CO_(2) molecules with small diameters and large quadrupole moment.In addition,the Ni0.11/Mg0.89-MOF-74 showed commendable cyclic stability,underscoring its promising potential for practical applications.
文摘High quality GaN films on (0001) sapphire substrates were grown by a commercial MOCVD system (Thomas Swan Corp.).The etch pits and threading dislocations(TDs) in GaN films have been studied by chemical etching methods such as mixed acid solution (H 3PO 4∶H 2SO 4=1∶3) and molten KOH,HCl vapor etching method,scanning electron microscope (SEM) and transmission electron microscope(TEM).SEM images of the same position of GaN films with HCl vapor etching and wet etching methods show notably different densities and shapes of etching pits.The results indicate that HCl vapor etching can show pure edge,pure screw and mixed TDs,mixed acid solution can show pure screw and mixed TDs and molten KOH wet etching only can show pure screw TDs.
文摘A new structure IGBT is proposed for reducing the power dissipation.It features a composite voltage-sustaining layer which includes a n-type buffer layer formed by ultra-deep diffusion and a transparent backside emitter formed by boron implantation.Working in a deep punch-through state during its normal operating condition,it still possesses all the characteristics of the robust non-punch-through IGBT (NPT-IGBT).With a chip-thickness thinner than that of the NPT-IGBT,the new structure presents a better trade-off relationship between the on-state voltage-drop and the turn-off loss.Experimental results show that the power loss of the new structure IGBT is 40% lower than that of the NPT-IGBT.
