The development of 3D structural composites with electromagnetic(EM)wave absorption could attenuate EM waves.Herein,magnetized flower-like Cu_(9)S_(5)/ZnFe_(2)O_(4)composites were fabricated through a multistep hydrot...The development of 3D structural composites with electromagnetic(EM)wave absorption could attenuate EM waves.Herein,magnetized flower-like Cu_(9)S_(5)/ZnFe_(2)O_(4)composites were fabricated through a multistep hydrothermal method.The crystallographic and surface phase chemical information,morphological structure,and magnetic and EM parameters of the composites were analyzed.The prepared Cu_(9)S_(5)/ZnFe_(2)O_(4)composites have multiple loss paths for EM waves and present an overall 3D flower-like structure.The Cu_(9)S_(5)/ZnFe_(2)O_(4)composites exhibit a minimum reflection loss of-54.38 dB and a broad effective absorption bandwidth of 5.92 GHz.Through magnetization,ZnFe_(2)O_(4)particles are self-assembled and grown on the surfaces of Cu_(9)S_(5).Such a modification is conducive to the generation of additional cross-linking contact sites and the effective introduction of a large number of phase interfaces,crystalline defects,special three-dimensional flower-like structures,and magneto-electrical coupling loss effects.Moreover,the synergistic effect of multiple loss strategies effectively improves EM wave absorption by the material.This work can provide a strategy for the use of magnetizationmodified sulfide composite functional materials in EM wave absorption.展开更多
Intensive measurements were conducted in Xi’an,China before and during a COVID-19 lockdown period to investigate how changes in anthropogenic emissions affected the optical properties and radiative effects of brown c...Intensive measurements were conducted in Xi’an,China before and during a COVID-19 lockdown period to investigate how changes in anthropogenic emissions affected the optical properties and radiative effects of brown carbon(BrC)aerosol.The contribution of BrC to total aerosol light absorption during the lockdown(13%-49%)was higher compared with the normal period(4%-29%).Mass absorption cross-sections(MACs)of specific organic aerosol(OA)factors were calculated from a ridge regression model.Of the primary OA(POA),coal combustion OA(CCOA)had the largest MACs at all tested wave-lengths during both periods due to high molecular-weight BrC chromophores;that was followed by biomass burning OA(BBOA)and hydrocarbon-like OA(HOA).For secondary OA(SOA),the MACs of the lessoxidized oxygenated OA(OOA)species(LO-OOA)atλ=370-590 nm were higher than those of more-oxidized OOA(MO-OOA)during both periods,presumably due to chromophore bleaching.The largest contributor to BrC absorption at the short wavelengths was CCOA during both periods,but BrC absorption by LO-OOA and MO-OOA became dominant at longer wavelengths during the lockdown.The estimated radiation forcing efficiency of BrC over 370-600 nm increased from 37.5 W·gduring the normal period to 50.2 W·gduring the lockdown,and that enhancement was mainly caused by higher MACs for both LO-OOA and MO-OOA.This study provides insights into the optical properties and radiative effects of source-specific BrC aerosol when pollution emissions are reduced.展开更多
Due to the compromise between exciton diffusion length and light absorption, the active layer thickness of organic solar cells(OSCs) is limited. As we all know, embedding metal nanostructures into OSCs can improve the...Due to the compromise between exciton diffusion length and light absorption, the active layer thickness of organic solar cells(OSCs) is limited. As we all know, embedding metal nanostructures into OSCs can improve the performance of OSCs by triggering surface plasma resonance, scattering, and other effect without increasing the physical thickness of light trapping layer. Besides, the plasma response and other roles will distinguish when metal nanostructures are embedded into different position of OSCs, which are equally important to the performance of OSCs. In this paper, the enhancement mechanisms of various metal nanostructures in different layers of OSCs are summarized from the electricity and optics aspects.This review also further highlights the progress of plasma effect and their working mechanism in OSCs,and it is expected to provide more perspective of plasma effect for performance enhancement of OSCs.展开更多
Absorption coefficient of biological tissue is an important parameter in biomedicine, but its determination remains a challenge. In this paper, we propose a method using focusing photoacoustic imaging technique and in...Absorption coefficient of biological tissue is an important parameter in biomedicine, but its determination remains a challenge. In this paper, we propose a method using focusing photoacoustic imaging technique and internal light irradiation of cylindrical diffusing fiber(CDF) to quantify the target optical absorption coefficient. Absorption coefficients for ink absorbers are firstly determined through photoacoustic and spectrophotometric measurements at the same excitation, which demonstrates the feasibility of this method. Also, the optical absorption coefficients of ink absorbers with several concentrations are measured. Finally, the two-dimensional scanning photoacoustic image is obtained. Optical absorption coefficient measurement and simultaneous photoacoustic imaging of absorber non-invasively are the typical characteristics of the method. This method can play a significant role for non-invasive determination of blood oxygen saturation, the absorption-based imaging and therapy.展开更多
The transient photovoltage of ITO/CuPc/AI is studied. The transient photovoltage under the Al side illumination is much greater than that under ITO side illumination. It is not negligible while light is almost complet...The transient photovoltage of ITO/CuPc/AI is studied. The transient photovoltage under the Al side illumination is much greater than that under ITO side illumination. It is not negligible while light is almost completely absorbed by the Al layer. It seems that the light absorption of the Al layer could enhance the generation of the photoinduced carriers in the organic layer, which is further shown by the transient photovoltage study of ITO/Al/NPB/Au. A possible mechanism proposed is that the holes generated in the Al are because of light absorption that is injected from the AI to organic materials. This results in further charge separation by the internal built-in electric field.展开更多
It is shown that the total escape speed u (i.e. from all the masses in space), which depends on the total gravitational potential U through the relation u = (−2U)1/2, tends to c;then, under the 1st condition...It is shown that the total escape speed u (i.e. from all the masses in space), which depends on the total gravitational potential U through the relation u = (−2U)1/2, tends to c;then, under the 1st condition c = u, and assuming (as a 2nd condition) the light as composed of longitudinally-extended, elastic (i.e. variable length) and massive particles, (photons), emitted at speed u referred to the initial location (O) of their source, we show that c referred to O becomes invariant despite any motion of its source from O. We revised the Doppler effect for the light, the gravitational redshift cause, the time dilation, highlighting the differences with respect to the Relativity. In the 2nd part, considering (3rd condition) the electron charge as a point-particle fixed to the electron surface and facing the atom nucleus during the electron orbit, the light-matter interaction becomes a consequence of the particular impacts between these photons and the circling electrons: e.g., on H atom, we found 137 circular orbits only, the last one being the ionization orbit, where the electron orbital speed becomes v i= c/1372. [Classical physics, under the assumption that a circling electron should produce (like a macroscopic electric circuit), an electro-magnetic radiation, implies that this claimed effect has to cause the electron fall into its nucleus: on Section 2.5, we show that the e.m. radiation of a circling electron only happens between two circular orbits].展开更多
基金This work was supported by the National Natural Science Foundation of China(No.51477002)the University Synergy Innovation Program of Anhui Province,China(No.GXXT-2019-028).
文摘The development of 3D structural composites with electromagnetic(EM)wave absorption could attenuate EM waves.Herein,magnetized flower-like Cu_(9)S_(5)/ZnFe_(2)O_(4)composites were fabricated through a multistep hydrothermal method.The crystallographic and surface phase chemical information,morphological structure,and magnetic and EM parameters of the composites were analyzed.The prepared Cu_(9)S_(5)/ZnFe_(2)O_(4)composites have multiple loss paths for EM waves and present an overall 3D flower-like structure.The Cu_(9)S_(5)/ZnFe_(2)O_(4)composites exhibit a minimum reflection loss of-54.38 dB and a broad effective absorption bandwidth of 5.92 GHz.Through magnetization,ZnFe_(2)O_(4)particles are self-assembled and grown on the surfaces of Cu_(9)S_(5).Such a modification is conducive to the generation of additional cross-linking contact sites and the effective introduction of a large number of phase interfaces,crystalline defects,special three-dimensional flower-like structures,and magneto-electrical coupling loss effects.Moreover,the synergistic effect of multiple loss strategies effectively improves EM wave absorption by the material.This work can provide a strategy for the use of magnetizationmodified sulfide composite functional materials in EM wave absorption.
基金financially supported by the Key Research and Development Program of Shaanxi Province(2018-ZDXM3-01)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB40000000)+3 种基金the Sino-Swiss Cooperation on Air Pollution for Better Air(7F-09802.01.02)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2019402)the Sino-Swiss Science and Technology Cooperation(SSSTC)project HAZECHINA(IZLCZ2_169986)the SDC Clean-Air-China Program(7F-09802.01.03)。
文摘Intensive measurements were conducted in Xi’an,China before and during a COVID-19 lockdown period to investigate how changes in anthropogenic emissions affected the optical properties and radiative effects of brown carbon(BrC)aerosol.The contribution of BrC to total aerosol light absorption during the lockdown(13%-49%)was higher compared with the normal period(4%-29%).Mass absorption cross-sections(MACs)of specific organic aerosol(OA)factors were calculated from a ridge regression model.Of the primary OA(POA),coal combustion OA(CCOA)had the largest MACs at all tested wave-lengths during both periods due to high molecular-weight BrC chromophores;that was followed by biomass burning OA(BBOA)and hydrocarbon-like OA(HOA).For secondary OA(SOA),the MACs of the lessoxidized oxygenated OA(OOA)species(LO-OOA)atλ=370-590 nm were higher than those of more-oxidized OOA(MO-OOA)during both periods,presumably due to chromophore bleaching.The largest contributor to BrC absorption at the short wavelengths was CCOA during both periods,but BrC absorption by LO-OOA and MO-OOA became dominant at longer wavelengths during the lockdown.The estimated radiation forcing efficiency of BrC over 370-600 nm increased from 37.5 W·gduring the normal period to 50.2 W·gduring the lockdown,and that enhancement was mainly caused by higher MACs for both LO-OOA and MO-OOA.This study provides insights into the optical properties and radiative effects of source-specific BrC aerosol when pollution emissions are reduced.
基金the National Key Research and Development Program of China (No. 2019YFA0705900) funded by MOSTthe National Natural Science Foundation of China (61875072)+4 种基金the Special Project of the Province-University Co-constructing Program of Jilin Province (SXGJXX2017-3)the National Postdoctoral Program for Innovative Talents (BX20190135)Scientific Research Planning Project of Education Department of Jilin Province (JJKH20200980KJ)Industrial Technology Research and Development Project of Jilin Province (2020C026-5)the International Cooperation and Exchange Project of Jilin Province (20170414002GH, 20180414001GH) for the support to this work。
文摘Due to the compromise between exciton diffusion length and light absorption, the active layer thickness of organic solar cells(OSCs) is limited. As we all know, embedding metal nanostructures into OSCs can improve the performance of OSCs by triggering surface plasma resonance, scattering, and other effect without increasing the physical thickness of light trapping layer. Besides, the plasma response and other roles will distinguish when metal nanostructures are embedded into different position of OSCs, which are equally important to the performance of OSCs. In this paper, the enhancement mechanisms of various metal nanostructures in different layers of OSCs are summarized from the electricity and optics aspects.This review also further highlights the progress of plasma effect and their working mechanism in OSCs,and it is expected to provide more perspective of plasma effect for performance enhancement of OSCs.
基金supported by the National Natural Science Foundation of China(Nos.61675043 and 81571726)the Natural Science Foundation of Fujian Province(Nos.2015J01006 and 2017J01742)the Doctoral Scientific Research Foundation of Jimei University(No.ZQ2016005)
文摘Absorption coefficient of biological tissue is an important parameter in biomedicine, but its determination remains a challenge. In this paper, we propose a method using focusing photoacoustic imaging technique and internal light irradiation of cylindrical diffusing fiber(CDF) to quantify the target optical absorption coefficient. Absorption coefficients for ink absorbers are firstly determined through photoacoustic and spectrophotometric measurements at the same excitation, which demonstrates the feasibility of this method. Also, the optical absorption coefficients of ink absorbers with several concentrations are measured. Finally, the two-dimensional scanning photoacoustic image is obtained. Optical absorption coefficient measurement and simultaneous photoacoustic imaging of absorber non-invasively are the typical characteristics of the method. This method can play a significant role for non-invasive determination of blood oxygen saturation, the absorption-based imaging and therapy.
基金supported by the Ministry of Science and Technology of China (Grant No. 2012CB921401)the National Natural Science Foundation of China (Grant No. 11134002)
文摘The transient photovoltage of ITO/CuPc/AI is studied. The transient photovoltage under the Al side illumination is much greater than that under ITO side illumination. It is not negligible while light is almost completely absorbed by the Al layer. It seems that the light absorption of the Al layer could enhance the generation of the photoinduced carriers in the organic layer, which is further shown by the transient photovoltage study of ITO/Al/NPB/Au. A possible mechanism proposed is that the holes generated in the Al are because of light absorption that is injected from the AI to organic materials. This results in further charge separation by the internal built-in electric field.
文摘It is shown that the total escape speed u (i.e. from all the masses in space), which depends on the total gravitational potential U through the relation u = (−2U)1/2, tends to c;then, under the 1st condition c = u, and assuming (as a 2nd condition) the light as composed of longitudinally-extended, elastic (i.e. variable length) and massive particles, (photons), emitted at speed u referred to the initial location (O) of their source, we show that c referred to O becomes invariant despite any motion of its source from O. We revised the Doppler effect for the light, the gravitational redshift cause, the time dilation, highlighting the differences with respect to the Relativity. In the 2nd part, considering (3rd condition) the electron charge as a point-particle fixed to the electron surface and facing the atom nucleus during the electron orbit, the light-matter interaction becomes a consequence of the particular impacts between these photons and the circling electrons: e.g., on H atom, we found 137 circular orbits only, the last one being the ionization orbit, where the electron orbital speed becomes v i= c/1372. [Classical physics, under the assumption that a circling electron should produce (like a macroscopic electric circuit), an electro-magnetic radiation, implies that this claimed effect has to cause the electron fall into its nucleus: on Section 2.5, we show that the e.m. radiation of a circling electron only happens between two circular orbits].
