Graphene(Gr)has unique properties including high electrical conductivity;Thus,graphene/copper(Gr/Cu)composites have attracted increasing attention to replace traditional Cu for electrical applications. However,the pro...Graphene(Gr)has unique properties including high electrical conductivity;Thus,graphene/copper(Gr/Cu)composites have attracted increasing attention to replace traditional Cu for electrical applications. However,the problem of how to control graphene to form desired Gr/Cu composite is not well solved. This paper aims at exploring the best parameters for preparing graphene with different layers on Cu foil by chemical vapor deposition(CVD)method and studying the effects of different layers graphene on Gr/Cu composite’s electrical conductivity. Graphene grown on single-sided and double-sided copper was prepared for Gr/Cu and Gr/Cu/Gr composites. The resultant electrical conductivity of Gr/Cu composites increased with decreasing graphene layers and increasing graphene volume fraction. The Gr/Cu/Gr composite with monolayer graphene owns volume fraction of less than 0.002%,producing the best electrical conductivity up to59.8 ×10^(6)S/m,equivalent to 104.5% IACS and 105.3% pure Cu foil.展开更多
Capacitive micromechanical ultrasonic transducers(CMUTs)have been widely studied because they can be used as substitutes for piezoelectric ultrasonic transducers in imaging applications.However,it is unclear whether a...Capacitive micromechanical ultrasonic transducers(CMUTs)have been widely studied because they can be used as substitutes for piezoelectric ultrasonic transducers in imaging applications.However,it is unclear whether and how CMUTs can be developed for sensors incorporating other functions.For instance,researchers have proposed the use of CMUTs for pressure sensing,but fundamental and practical application issues remain unsolved.This study explored ways in which a pressure sensor can be properly developed based on a CMUT prototype using a simulation approach.A three-dimensional finite element model of CMUTs was designed using the COMSOL Multiphysics software by combining the working principle of CMUTs with pressure sensing characteristics in which the resonance frequency of the CMUT cell shifts accordingly when it is subjected to an external pressure.Simultaneously,when subjected to pressure,the CMUT membrane deforms,thus the pressure can be reflected by the change in the capacitance.展开更多
OBJECTIVE: To evaluate the effects of Jidesheng anti-venom used externally for skin and soft-tissue necrosis from Chinese cobra bite.METHODS: A retrospective review was performed according to the clinical data recorde...OBJECTIVE: To evaluate the effects of Jidesheng anti-venom used externally for skin and soft-tissue necrosis from Chinese cobra bite.METHODS: A retrospective review was performed according to the clinical data recorded from January 2002 to December 2012. A total of 126 patients(116 females and 10 males) with skin and soft-tissue necrosis due to Chinese cobra bite were divided into two groups. The control group was treated externally with 40% glyceride magnesium sulfate(n=52), and the treatment group was given Jidesheng anti-venom externally(n=74). The data collected included maximum local necrotic area of skin and soft tissues, de-tumescence time, healing time,and skin-grafting rate.RESULTS: There were no significant differences in gender, age, and disease condition between the control and treatment groups(P>0.05). No statistically significant difference was found in de-tumescence time between the two groups(P>0.05). The maximum local necrotic area of skin and soft tissues was(19.9 ± 7.3) cm2in the treatment group,while it was(23.3±6.4) cm2in the control group.The healing time of the treatment group was shorter than that of the control group [(32.1 ± 3.7) vs(34.4±4.5) days)] The skin-grafting rate in the treatment group was lower than that of the control group(10.81% vs 25.00%). There were statistically significant differences in maximum local necrotic area of skin and soft tissues, healing time, and skin-grafting rate between the control and treatment groups(all P<0.05).CONCLUSION: External application of Jidesheng anti-venom may help to promote wound healing and reduce the skin-grafting rate in cases of skin and soft-tissue necrosis due to Chinese cobra bite.展开更多
The authors have studied the electronic structure and transport properties of hybrid nanowires made of a copper chain adsorbed on a single-wall carbon nanotube(CNT)using first principle methods.Results have shown that...The authors have studied the electronic structure and transport properties of hybrid nanowires made of a copper chain adsorbed on a single-wall carbon nanotube(CNT)using first principle methods.Results have shown that after the adsorption of the Cu chain,the density of states and the transmission coefficients of the CNT(5,5)/Cu nanowire have been increased,while the band gap of CNT(10,0)/Cu have been significantly reduced.These results imply that the conductivity of CNTs,either metallic or semiconducting,have been enhanced by the adsorption of a copper chain.These hybrid nanowires with enhanced conductivity may be suitable for nanoelectronics.展开更多
基金supported substantially by the Southwest Jiaotong University for Material and Financial Support。
文摘Graphene(Gr)has unique properties including high electrical conductivity;Thus,graphene/copper(Gr/Cu)composites have attracted increasing attention to replace traditional Cu for electrical applications. However,the problem of how to control graphene to form desired Gr/Cu composite is not well solved. This paper aims at exploring the best parameters for preparing graphene with different layers on Cu foil by chemical vapor deposition(CVD)method and studying the effects of different layers graphene on Gr/Cu composite’s electrical conductivity. Graphene grown on single-sided and double-sided copper was prepared for Gr/Cu and Gr/Cu/Gr composites. The resultant electrical conductivity of Gr/Cu composites increased with decreasing graphene layers and increasing graphene volume fraction. The Gr/Cu/Gr composite with monolayer graphene owns volume fraction of less than 0.002%,producing the best electrical conductivity up to59.8 ×10^(6)S/m,equivalent to 104.5% IACS and 105.3% pure Cu foil.
文摘Capacitive micromechanical ultrasonic transducers(CMUTs)have been widely studied because they can be used as substitutes for piezoelectric ultrasonic transducers in imaging applications.However,it is unclear whether and how CMUTs can be developed for sensors incorporating other functions.For instance,researchers have proposed the use of CMUTs for pressure sensing,but fundamental and practical application issues remain unsolved.This study explored ways in which a pressure sensor can be properly developed based on a CMUT prototype using a simulation approach.A three-dimensional finite element model of CMUTs was designed using the COMSOL Multiphysics software by combining the working principle of CMUTs with pressure sensing characteristics in which the resonance frequency of the CMUT cell shifts accordingly when it is subjected to an external pressure.Simultaneously,when subjected to pressure,the CMUT membrane deforms,thus the pressure can be reflected by the change in the capacitance.
基金Supported by Guangxi Natural Science Foundation (No.2012GXNSFAA276011 and No.2013GXNSFBA019163)Youth Science Foundation of Guangxi Medical University (No.GXMUYSF201216)
文摘OBJECTIVE: To evaluate the effects of Jidesheng anti-venom used externally for skin and soft-tissue necrosis from Chinese cobra bite.METHODS: A retrospective review was performed according to the clinical data recorded from January 2002 to December 2012. A total of 126 patients(116 females and 10 males) with skin and soft-tissue necrosis due to Chinese cobra bite were divided into two groups. The control group was treated externally with 40% glyceride magnesium sulfate(n=52), and the treatment group was given Jidesheng anti-venom externally(n=74). The data collected included maximum local necrotic area of skin and soft tissues, de-tumescence time, healing time,and skin-grafting rate.RESULTS: There were no significant differences in gender, age, and disease condition between the control and treatment groups(P>0.05). No statistically significant difference was found in de-tumescence time between the two groups(P>0.05). The maximum local necrotic area of skin and soft tissues was(19.9 ± 7.3) cm2in the treatment group,while it was(23.3±6.4) cm2in the control group.The healing time of the treatment group was shorter than that of the control group [(32.1 ± 3.7) vs(34.4±4.5) days)] The skin-grafting rate in the treatment group was lower than that of the control group(10.81% vs 25.00%). There were statistically significant differences in maximum local necrotic area of skin and soft tissues, healing time, and skin-grafting rate between the control and treatment groups(all P<0.05).CONCLUSION: External application of Jidesheng anti-venom may help to promote wound healing and reduce the skin-grafting rate in cases of skin and soft-tissue necrosis due to Chinese cobra bite.
基金supported by the National Science Foundation,USA.
文摘The authors have studied the electronic structure and transport properties of hybrid nanowires made of a copper chain adsorbed on a single-wall carbon nanotube(CNT)using first principle methods.Results have shown that after the adsorption of the Cu chain,the density of states and the transmission coefficients of the CNT(5,5)/Cu nanowire have been increased,while the band gap of CNT(10,0)/Cu have been significantly reduced.These results imply that the conductivity of CNTs,either metallic or semiconducting,have been enhanced by the adsorption of a copper chain.These hybrid nanowires with enhanced conductivity may be suitable for nanoelectronics.
