Recent Advances in Design Strategies and Multifunctionality of Flexible Electromagnetic Interference Shielding Materials

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.

First principles investigation on Li or Sn codoped hexagonal tungsten bronzes as the near-infrared shielding material

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.

Research Progress of Metal-Based Shielding Materials for Neutron and Gamma Rays

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.

MICROSTRUCTURE AND PROPERTIES OF HIGH BORON BEARING STEEL

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.