Lightning interception technology is one of the three core technical systems of regional lightning protection theory.Among them,the omni-directional multi-pulse lightning interceptor(hereinafter referred to as lightni...Lightning interception technology is one of the three core technical systems of regional lightning protection theory.Among them,the omni-directional multi-pulse lightning interceptor(hereinafter referred to as lightning interceptor,the same below)has the ability to attenuate lightning current≥40%and significantly reduce the intensity of the spatial electromagnetic field around the lightning point.In order to explore the attenuation mechanism and effect of lightning interceptor to lightning current,this paper analyzed a lightning stroke process at 16:00 on August 19,2022,and tried to explain the attenuation effect of lightning interceptor to lightning current with the physical parameters of lightning stroke.展开更多
Nonlinear effects will occur during the transmission of the finite amplitude wave in biological tissues. The theoretical prediction and experimental demonstration of the nonlinear effects on the propagation of the fin...Nonlinear effects will occur during the transmission of the finite amplitude wave in biological tissues. The theoretical prediction and experimental demonstration of the nonlinear effects on the propagation of the finite amplitude wave at the range of biomedical ultrasound frequency and intensity are studied. Results show that the efficiency factor and effective propagation distance will decrease while the attenuation coefficient increases due to the existence of nonlinear effects. The experimental results coincided quite well with the theory. This shows that the effective propagation distance and efficiency factor can be used to describe quantitatively the influence of nonlinear effects on the propagation of the finite amplitude sound wave in biological tissues.展开更多
Gamma rays is widely used in modern science and technology,but it may cause health damage to practitioners.In the present study,natural composites based on leather and high-Z elements(atomic number≥56)were fabricated...Gamma rays is widely used in modern science and technology,but it may cause health damage to practitioners.In the present study,natural composites based on leather and high-Z elements(atomic number≥56)were fabricated and used as gamma rays shielding materials.These shielding materials were prepared by coating rare earth nanoparticles(Er_(2)O_(3)or La2O3)onto the surface of natural leather,which was first impregnated with Bi^(3+)and Ba^(2+).Results show that the attenuation efficiency of the prepared Er1.31Bi5.46-NL(1.31 and 5.46 mmol cm^(−3)loaded elements)with thickness of 3.2 mm was 61.57%for incident rays at 121.78 keV(152Eu)and reached 96.4%in the incident of 59.5 keV(241Am),which is comparable to that of 0.25-mm lead plate(54.54 mmol cm−3).In addition,these natural-leather-based shielding materials exhibited low density(approximately 1/10 of Pb),high strength and wearable behaviors.展开更多
Gamma rays is widely used in modern science and technology,but it may cause health damage to practitioners.In the present study,natural composites based on leather and high-Z elements(atomic number≥56)were fabricated...Gamma rays is widely used in modern science and technology,but it may cause health damage to practitioners.In the present study,natural composites based on leather and high-Z elements(atomic number≥56)were fabricated and used as gamma rays shielding materials.These shielding materials were prepared by coating rare earth nano-particles(Er_(2)O_(3)or La_(2)O_(3))onto the surface of natural leather,which was first impregnated with Bi^(3+)and Ba^(2+).Results show that the attenuation efficiency of the prepared Er_(131)Bi_(546)-NL(1.31 and 5.46 mmol cm^(-3)loaded elements)with thickness of 3.2 mm was 61.57%for incident rays at 121.78 keV(^(152)Eu)and reached 96.4%in the incident of 59.5 keV(^(241)Am),which is comparable to that of 0.25-mm lead plate(54.54 mmol cm^(-3)).In addition,these natural-leather-based shielding materials exhibited low density(approximately 1/10 of Pb),high strength and wearable behaviors.展开更多
基金Supported by Technology Research and Development Project of Strong Electro-magnetic Pulse Protection(Lightning)of Sea Wind Field in Guangdong Yuedi-an Zhuhai Biqing Bay.
文摘Lightning interception technology is one of the three core technical systems of regional lightning protection theory.Among them,the omni-directional multi-pulse lightning interceptor(hereinafter referred to as lightning interceptor,the same below)has the ability to attenuate lightning current≥40%and significantly reduce the intensity of the spatial electromagnetic field around the lightning point.In order to explore the attenuation mechanism and effect of lightning interceptor to lightning current,this paper analyzed a lightning stroke process at 16:00 on August 19,2022,and tried to explain the attenuation effect of lightning interceptor to lightning current with the physical parameters of lightning stroke.
文摘Nonlinear effects will occur during the transmission of the finite amplitude wave in biological tissues. The theoretical prediction and experimental demonstration of the nonlinear effects on the propagation of the finite amplitude wave at the range of biomedical ultrasound frequency and intensity are studied. Results show that the efficiency factor and effective propagation distance will decrease while the attenuation coefficient increases due to the existence of nonlinear effects. The experimental results coincided quite well with the theory. This shows that the effective propagation distance and efficiency factor can be used to describe quantitatively the influence of nonlinear effects on the propagation of the finite amplitude sound wave in biological tissues.
基金The National Natural Science Foundation of China(No.21878191).
文摘Gamma rays is widely used in modern science and technology,but it may cause health damage to practitioners.In the present study,natural composites based on leather and high-Z elements(atomic number≥56)were fabricated and used as gamma rays shielding materials.These shielding materials were prepared by coating rare earth nanoparticles(Er_(2)O_(3)or La2O3)onto the surface of natural leather,which was first impregnated with Bi^(3+)and Ba^(2+).Results show that the attenuation efficiency of the prepared Er1.31Bi5.46-NL(1.31 and 5.46 mmol cm^(−3)loaded elements)with thickness of 3.2 mm was 61.57%for incident rays at 121.78 keV(152Eu)and reached 96.4%in the incident of 59.5 keV(241Am),which is comparable to that of 0.25-mm lead plate(54.54 mmol cm−3).In addition,these natural-leather-based shielding materials exhibited low density(approximately 1/10 of Pb),high strength and wearable behaviors.
基金The National Natural Science Foundation of China(No,21878191).
文摘Gamma rays is widely used in modern science and technology,but it may cause health damage to practitioners.In the present study,natural composites based on leather and high-Z elements(atomic number≥56)were fabricated and used as gamma rays shielding materials.These shielding materials were prepared by coating rare earth nano-particles(Er_(2)O_(3)or La_(2)O_(3))onto the surface of natural leather,which was first impregnated with Bi^(3+)and Ba^(2+).Results show that the attenuation efficiency of the prepared Er_(131)Bi_(546)-NL(1.31 and 5.46 mmol cm^(-3)loaded elements)with thickness of 3.2 mm was 61.57%for incident rays at 121.78 keV(^(152)Eu)and reached 96.4%in the incident of 59.5 keV(^(241)Am),which is comparable to that of 0.25-mm lead plate(54.54 mmol cm^(-3)).In addition,these natural-leather-based shielding materials exhibited low density(approximately 1/10 of Pb),high strength and wearable behaviors.
