With the rapid advancement of terahertz technologies,electromagnetic interference(EMI)shielding materials are needed to ensure secure electromagnetic environments.Enormous efforts have been devoted to achieving highly...With the rapid advancement of terahertz technologies,electromagnetic interference(EMI)shielding materials are needed to ensure secure electromagnetic environments.Enormous efforts have been devoted to achieving highly efficient EMI shielding films by enhancing flexibility,lightweight,mechanical robustness,and high shielding efficiency.However,the consideration of the optical properties of these shielding materials is still in its infancy.By incorporating transparency,visual information from protected systems can be preserved for monitoring interior working conditions,and the optical imperceptibility allows nonoffensive and easy cover of shielding materials for both device and biology.There are many materials that can be applied to transparent EMI shields.In particular,two-dimensional transition metal carbide/nitrides(MXenes),possessing the advantages of superior conductivity,optical properties,favorable flexibility,and facile processibility,have become a great candidate.This work reviews the recent research on developing highly efficient and optically transparent EMI shields in a comprehensive way.Materials from MXenes,indium tin oxide,metal,carbon,and conductive polymers are covered,with a focus on the employment of MXene-based composites in transparent EMI shielding.The prospects and challenges for the future development of MXene-based transparent EMI shields are discussed.This work aims to promote the development of high-performance,optically transparent EMI shields for broader applications by leveraging MXenes.展开更多
The radiation generated by nuclear reaction is harmful to human body and equipment,thus the radiation shielding materials that employ the shielding ability from neutron and gamma rays are the best candidates according...The radiation generated by nuclear reaction is harmful to human body and equipment,thus the radiation shielding materials that employ the shielding ability from neutron and gamma rays are the best candidates according to application situations and radiation sources.In this paper,the researches of metal-based neutron and gamma rays or multiple purpose shielding materials are systematically summarized,and the respective and principal problems of these materials with respect to shielding effectiveness and other performances,such as corrosion,mechanical properties,manufacture,etc.,are discussed.Finally,the prospect of shielding materials is outlined,which suggests that the development of highly efficient and multiply functional radiation shielding materials with good environmental compatibility is one of the future development trends.展开更多
With rapid development of 5G communication technologies,electromagnetic interference(EMI)shielding for electronic devices has become an urgent demand in recent years,where the development of corresponding EMI shieldin...With rapid development of 5G communication technologies,electromagnetic interference(EMI)shielding for electronic devices has become an urgent demand in recent years,where the development of corresponding EMI shielding materials against detrimental electromagnetic radiation plays an essential role.Meanwhile,the EMI shielding materials with high flexibility and functional integrity are highly demanded for emerging shielding applications.Hitherto,a variety of flexible EMI shielding materials with lightweight and multifunctionalities have been developed.In this review,we not only introduce the recent development of flexible EMI shielding materials,but also elaborate the EMI shielding mechanisms and the index for"green EMI shielding"performance.In addition,the construction strategies for sophisticated multifunctionalities of flexible shielding materials are summarized.Finally,we propose several possible research directions for flexible EMI shielding materials in near future,which could be inspirational to the fast-growing next-generation flexible electronic devices with reliable and multipurpose protections as offered by EMI shielding materials.展开更多
The 52%energy of the solar radiation is contributed by near-infrared radiation(NIR,780-2500 nm).Therefore,the material design for the energy-saving smart window,which can effectively shield NIR and has acceptable visi...The 52%energy of the solar radiation is contributed by near-infrared radiation(NIR,780-2500 nm).Therefore,the material design for the energy-saving smart window,which can effectively shield NIR and has acceptable visible transmittance,is vital to save the energy consumed on the temperature control system.It is important to find a non-toxic stable material with excellent NIR-shielding ability and acceptable visible transmittance.The systematic first-principles study on Li_(x)Sn_(y)WO_(3)(x=0,0.33,0.66,and y=0,0.33)exhibits that the chemical stability is a positive correlation with the doping concentration.After doping,the Fermi-energy upshifts into the conduction band,and the material shows metal-like characteristics.Therefore,these structures Li_(x)Sn_(y)WO_(3)(except the structure with x=0.33 and y=0)show pronounced improvement of NIR shielding ability.Our results indicate that when x=0 and y=0.33,the material exhibits the strongest NIR-shielding ability,satisfying chemical stability,wide NIR-shielding range(780-2500 nm),and acceptable visible transmittance.This work provides a good choice for experimental study on NIR shielding material for the energy-saving window.展开更多
Flexible absorption-dominant electromagneticinterference (EMI) shielding materials are essential for sensitiveelectronic devices, such as those in telecommunications,the automotive industry, aerospace, and flexible el...Flexible absorption-dominant electromagneticinterference (EMI) shielding materials are essential for sensitiveelectronic devices, such as those in telecommunications,the automotive industry, aerospace, and flexible electronics,owing to their lower reflection of electromagnetic waves, aswell as their adaptability and lightweight. However, it is still agreat challenge to achieve high absorption ability and widebandwidth simultaneously, along with the flexibility to accommodatedevice deformation. In this study, flexible multilayer Ti_(3)C_(2)T_(x) (ML-Ti_(3)C_(2)T_(x))/polytetrafluoroethylene (PTFE)composite films with adjustable EMI shielding ability werefabricated via a roll-to-roll method. The multiple loss mechanismsinduced by the cavity structure of the ML-Ti_(3)C_(2)T_(x) microparticles and the "brick-mortar" network of the compositefilm provide more channels for multiple reflections andscattering of incident electromagnetic waves. In addition, theimpedance matching could be customized by controlling thethickness of the film and the ratio of ML-Ti_(3)C_(2)T_(x) to achievehigh absorption ability. As a result, a high EMI shielding effectivenessvalue of 70 dB in the X-band with only 0.0004%reflection is achieved by the 3.5-mm ML-Ti_(3)C_(2)T_(x)/PTFE-25 wt% film. Notably, benefiting from the strong interactions betweenthe two components, the properties of the films remainconstant even after deformation and extremely low-temperature(-200℃) treatment, indicating promising potential forfuture multiple applications.展开更多
High boron bearing steel, in which boron homogeneously distributed, wassuccessfully produced in the vacuum induction furnace. The microstructural observations of cast andhot rolled steels showed that the addition of t...High boron bearing steel, in which boron homogeneously distributed, wassuccessfully produced in the vacuum induction furnace. The microstructural observations of cast andhot rolled steels showed that the addition of titanium can eliminate the quantity of ferrous boridesprecipitated at the grain boundaries and break the net microstructure, as a result, its hotworkability is improved. The titanium boride TiB_2 homogeneously distributes in the matrix ofalpha-Fe. The parameters of hot rolling process, including preheated temperature, initial rollingtemperature, finished rolling temperature and the total deformation, have been optimized.展开更多
基金This work was supported by the National Key R&DProgram of China(No.2021YFB3502500)the NationalNatural Science Foundation of China(Nos.22205131,22375115)+6 种基金the Natural Science Foundation of ShandongProvince(Nos.2022HYYQ-014 ,ZR2016BM16)the New 20 Funded Programs for Universities of Jinan(2021GXRC036)Provincial Key Research and Develop-ment Program of Shandong(2021ZLGX01)the Disci-pline Construction Expenditure for Distinguished Young Scholars of Shandong University(31370089963141)Shenzhen Municipal Special Fund for Guiding LocalScientific and Technological Development(China,2021Szvup071)Qilu Young Scholar Program ofShandong University(No.31370082163127)The authorsacknowledge the assistance of the Shandong UniversityTesting and Manufacturing Center for Advanced Materi-als and the support of the Xiaomi Foundation/XiaomiYoung Talents Program.
文摘With the rapid advancement of terahertz technologies,electromagnetic interference(EMI)shielding materials are needed to ensure secure electromagnetic environments.Enormous efforts have been devoted to achieving highly efficient EMI shielding films by enhancing flexibility,lightweight,mechanical robustness,and high shielding efficiency.However,the consideration of the optical properties of these shielding materials is still in its infancy.By incorporating transparency,visual information from protected systems can be preserved for monitoring interior working conditions,and the optical imperceptibility allows nonoffensive and easy cover of shielding materials for both device and biology.There are many materials that can be applied to transparent EMI shields.In particular,two-dimensional transition metal carbide/nitrides(MXenes),possessing the advantages of superior conductivity,optical properties,favorable flexibility,and facile processibility,have become a great candidate.This work reviews the recent research on developing highly efficient and optically transparent EMI shields in a comprehensive way.Materials from MXenes,indium tin oxide,metal,carbon,and conductive polymers are covered,with a focus on the employment of MXene-based composites in transparent EMI shielding.The prospects and challenges for the future development of MXene-based transparent EMI shields are discussed.This work aims to promote the development of high-performance,optically transparent EMI shields for broader applications by leveraging MXenes.
文摘The radiation generated by nuclear reaction is harmful to human body and equipment,thus the radiation shielding materials that employ the shielding ability from neutron and gamma rays are the best candidates according to application situations and radiation sources.In this paper,the researches of metal-based neutron and gamma rays or multiple purpose shielding materials are systematically summarized,and the respective and principal problems of these materials with respect to shielding effectiveness and other performances,such as corrosion,mechanical properties,manufacture,etc.,are discussed.Finally,the prospect of shielding materials is outlined,which suggests that the development of highly efficient and multiply functional radiation shielding materials with good environmental compatibility is one of the future development trends.
基金This work was financially supported by the National Natural Science Foundation of China(51725101,11727807,51672050,61790581,52102368,52101213)the Ministry of Science and Technology of China(973 Project No.2018YFA0209102)+6 种基金University Development Fund(UDF0100152)the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(Grant No.2017ZT07C291)Shenzhen Science and Technology Program(Grant No.KQTD20170810141424366)China Postdoctoral Science Foundation(Grant No.2020M680085)Regional Joint Fund for Basic Research and Applied Basic Research of Guangdong Province(No.2020SA001515110905)Science and Technology Department of Jiangsu Province of China(Grant No.BK20210261)Open access funding provided by Shanghai Jiao Tong University
文摘With rapid development of 5G communication technologies,electromagnetic interference(EMI)shielding for electronic devices has become an urgent demand in recent years,where the development of corresponding EMI shielding materials against detrimental electromagnetic radiation plays an essential role.Meanwhile,the EMI shielding materials with high flexibility and functional integrity are highly demanded for emerging shielding applications.Hitherto,a variety of flexible EMI shielding materials with lightweight and multifunctionalities have been developed.In this review,we not only introduce the recent development of flexible EMI shielding materials,but also elaborate the EMI shielding mechanisms and the index for"green EMI shielding"performance.In addition,the construction strategies for sophisticated multifunctionalities of flexible shielding materials are summarized.Finally,we propose several possible research directions for flexible EMI shielding materials in near future,which could be inspirational to the fast-growing next-generation flexible electronic devices with reliable and multipurpose protections as offered by EMI shielding materials.
文摘The 52%energy of the solar radiation is contributed by near-infrared radiation(NIR,780-2500 nm).Therefore,the material design for the energy-saving smart window,which can effectively shield NIR and has acceptable visible transmittance,is vital to save the energy consumed on the temperature control system.It is important to find a non-toxic stable material with excellent NIR-shielding ability and acceptable visible transmittance.The systematic first-principles study on Li_(x)Sn_(y)WO_(3)(x=0,0.33,0.66,and y=0,0.33)exhibits that the chemical stability is a positive correlation with the doping concentration.After doping,the Fermi-energy upshifts into the conduction band,and the material shows metal-like characteristics.Therefore,these structures Li_(x)Sn_(y)WO_(3)(except the structure with x=0.33 and y=0)show pronounced improvement of NIR shielding ability.Our results indicate that when x=0 and y=0.33,the material exhibits the strongest NIR-shielding ability,satisfying chemical stability,wide NIR-shielding range(780-2500 nm),and acceptable visible transmittance.This work provides a good choice for experimental study on NIR shielding material for the energy-saving window.
基金supported by the National Natural Science Foundation of China (22105106, 52105576, 22005151, and 62404113)the Natural Science Foundation of Jiangsu Province of China (BK20210603)+1 种基金the National Natural Science Foundation of China (NY221003)the Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYCX24_1171 and KYCX22_1010)。
文摘Flexible absorption-dominant electromagneticinterference (EMI) shielding materials are essential for sensitiveelectronic devices, such as those in telecommunications,the automotive industry, aerospace, and flexible electronics,owing to their lower reflection of electromagnetic waves, aswell as their adaptability and lightweight. However, it is still agreat challenge to achieve high absorption ability and widebandwidth simultaneously, along with the flexibility to accommodatedevice deformation. In this study, flexible multilayer Ti_(3)C_(2)T_(x) (ML-Ti_(3)C_(2)T_(x))/polytetrafluoroethylene (PTFE)composite films with adjustable EMI shielding ability werefabricated via a roll-to-roll method. The multiple loss mechanismsinduced by the cavity structure of the ML-Ti_(3)C_(2)T_(x) microparticles and the "brick-mortar" network of the compositefilm provide more channels for multiple reflections andscattering of incident electromagnetic waves. In addition, theimpedance matching could be customized by controlling thethickness of the film and the ratio of ML-Ti_(3)C_(2)T_(x) to achievehigh absorption ability. As a result, a high EMI shielding effectivenessvalue of 70 dB in the X-band with only 0.0004%reflection is achieved by the 3.5-mm ML-Ti_(3)C_(2)T_(x)/PTFE-25 wt% film. Notably, benefiting from the strong interactions betweenthe two components, the properties of the films remainconstant even after deformation and extremely low-temperature(-200℃) treatment, indicating promising potential forfuture multiple applications.
基金This work was stLPPorted by the Foundation of Key Teacher Of State Education Min-istry, China.
文摘High boron bearing steel, in which boron homogeneously distributed, wassuccessfully produced in the vacuum induction furnace. The microstructural observations of cast andhot rolled steels showed that the addition of titanium can eliminate the quantity of ferrous boridesprecipitated at the grain boundaries and break the net microstructure, as a result, its hotworkability is improved. The titanium boride TiB_2 homogeneously distributes in the matrix ofalpha-Fe. The parameters of hot rolling process, including preheated temperature, initial rollingtemperature, finished rolling temperature and the total deformation, have been optimized.
