Attributed to the intense development and complexity in electronic devices,energy dissipation is becoming more essential nowadays.The carbonaceous materials particularly graphene(Gr)-based thermal interface materials(...Attributed to the intense development and complexity in electronic devices,energy dissipation is becoming more essential nowadays.The carbonaceous materials particularly graphene(Gr)-based thermal interface materials(TIMs)are exceptional in heat management.However,because of the anisotropic behavior of Gr in composites,the TIMs having outstanding through-plane thermal conductivity(┴TC)are needed to fulfill the upcoming innovation in numerous devices.In order to achieve this,herein,nano-urethane linkage-based modified Gr and carbon fibers architecture termed as nanourethane linkage(NUL)-Gr/carbon fibers(CFs)is fabricated.Wherein,toluene diisocyanate is utilized to develop a novel but simple NUL to shape a new interface between graphene sheets.Interestingly,the prepared composite of NUL-Gr/CFs with polyvinylidene fluoride matrix shows outstanding performance in heat management.Owing to the unique structure of NUL-Gr/CFs,an unprecedented value of┴TC(~7.96 W·m^–1·K^–1)is achieved at a low filler fraction of 13.8 wt.%which translates into an improvement of^3,980%of pristine polymer.The achieved outcomes elucidate the significance of the covalent interaction between graphene sheets as well as strong bonding among graphene and matrix in the composites and manifest the potential of proposed NUL-Gr/CFs architecture for practical applications.展开更多
Objective To evaluate the low melting-point MCP-69,MCP-96,MCP-137,and MCP-200 alloys,and characterize them for their potential to protect from the harms associated with radiation and eliminate radiation hazards during...Objective To evaluate the low melting-point MCP-69,MCP-96,MCP-137,and MCP-200 alloys,and characterize them for their potential to protect from the harms associated with radiation and eliminate radiation hazards during radiological procedures and treatment of cancer.Methods The Klein-Nishina formula was used to calculate the electronic and atomic cross-sections of these alloys using photon beams with energies 4,6,9,12,and 18MeV.Energy transfer coefficients,Compton mass attenuation coefficient,mass-energy transfer coefficient,and recoil energy of electrons in the specific photon energies of 4–18MeV were calculated.The alloys'effective charge number and the photon energy were key factors in determining the properties found by utilizing the Klein-Nishina formula and Compton effects.Results The cross sections and energy transfer coefficients increased with the increasing effective charge number Z of the alloys and decreased as the photon energy increased.The Compton recoil of the ejected electrons was observed to have a direct relationship with photon energy,but mass-energy transfer decreased with increasing photon energy.These alloys can replace the toxic lead for environmentally cleaned radiation applications.Conclusions These calculations and characteristics of the MCP alloys can help further determine their viability as materials for radiation shielding,their use in safe cancer diagnosis,treatment,and environmental hazards protection.展开更多
基金the Nature Science Associate Foundation(NSAF)(No.U1730103)the National Natural Science Foundation of China(NSFC)(No.11672002)。
文摘Attributed to the intense development and complexity in electronic devices,energy dissipation is becoming more essential nowadays.The carbonaceous materials particularly graphene(Gr)-based thermal interface materials(TIMs)are exceptional in heat management.However,because of the anisotropic behavior of Gr in composites,the TIMs having outstanding through-plane thermal conductivity(┴TC)are needed to fulfill the upcoming innovation in numerous devices.In order to achieve this,herein,nano-urethane linkage-based modified Gr and carbon fibers architecture termed as nanourethane linkage(NUL)-Gr/carbon fibers(CFs)is fabricated.Wherein,toluene diisocyanate is utilized to develop a novel but simple NUL to shape a new interface between graphene sheets.Interestingly,the prepared composite of NUL-Gr/CFs with polyvinylidene fluoride matrix shows outstanding performance in heat management.Owing to the unique structure of NUL-Gr/CFs,an unprecedented value of┴TC(~7.96 W·m^–1·K^–1)is achieved at a low filler fraction of 13.8 wt.%which translates into an improvement of^3,980%of pristine polymer.The achieved outcomes elucidate the significance of the covalent interaction between graphene sheets as well as strong bonding among graphene and matrix in the composites and manifest the potential of proposed NUL-Gr/CFs architecture for practical applications.
文摘Objective To evaluate the low melting-point MCP-69,MCP-96,MCP-137,and MCP-200 alloys,and characterize them for their potential to protect from the harms associated with radiation and eliminate radiation hazards during radiological procedures and treatment of cancer.Methods The Klein-Nishina formula was used to calculate the electronic and atomic cross-sections of these alloys using photon beams with energies 4,6,9,12,and 18MeV.Energy transfer coefficients,Compton mass attenuation coefficient,mass-energy transfer coefficient,and recoil energy of electrons in the specific photon energies of 4–18MeV were calculated.The alloys'effective charge number and the photon energy were key factors in determining the properties found by utilizing the Klein-Nishina formula and Compton effects.Results The cross sections and energy transfer coefficients increased with the increasing effective charge number Z of the alloys and decreased as the photon energy increased.The Compton recoil of the ejected electrons was observed to have a direct relationship with photon energy,but mass-energy transfer decreased with increasing photon energy.These alloys can replace the toxic lead for environmentally cleaned radiation applications.Conclusions These calculations and characteristics of the MCP alloys can help further determine their viability as materials for radiation shielding,their use in safe cancer diagnosis,treatment,and environmental hazards protection.
