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Marine Green Algae as a Supplement for Chlorophyll and Other Nutrients in Vigna Radiata under UV-C Radiation-Induced Stress
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作者 Rafia Azmat Hajra Nasreen 《Journal of Chemistry and Chemical Engineering》 2010年第5期1-7,共7页
The potential protective effect of marine green algae (Codium iyengerii) was examined in UV-C treated seedlings of Vigna radiata. The study comprises of three treatments of UV-C radiation (100-290 nm) dose for one... The potential protective effect of marine green algae (Codium iyengerii) was examined in UV-C treated seedlings of Vigna radiata. The study comprises of three treatments of UV-C radiation (100-290 nm) dose for one min in alternative days. This results in deformed morphological parameters, including: decrease in plant height, fresh mass of leaves, shoots and roots, as well as leaf areas, which may be attributed with decreased in the relative growth rate, carbohydrate, amino acids, and protein contents of plant. A drastic effect of UV-C radiation was found on the photosynthetic apparatus where increase in red pigmentations on the leaves surface indicates the presence of UV-C absorbing pigments instead of chloroplast pigments. Visible spectrum of leaves chlorophyll showed reduced concentration of visible absorbing pigments which showed the deleterious effect of these radiations on physiological processes of seedlings. These negative effects of UV-C radiation on plant growth were found to be decreased by the application of green seaweed (Codium iyengerii), and absorption spectrums of chloroplast contents showed that UV-C radiation inducing damages were appropriately managed by enhanced concentration of seaweeds which significantly increased morphological and physiological parameters like leaf, stem, root biomass, and plant height under UV-C radiation were observed. 展开更多
关键词 SURVIVAL uv-c radiation codium iyengerii spectrums morphological and physiological parameterss.
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KCl:Eu^(2+) as a solar UV-C radiation dosimeter. Optically stimulated luminescence and thermoluminescence analyses 被引量:1
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作者 I.Aguirre de Cárcer H.L.D'Antoni +2 位作者 M.Barboza-Flores V.Correcher F.Jaque 《Journal of Rare Earths》 SCIE EI CAS CSCD 2009年第4期579-583,共5页
The KCI:Eu2+ system response to UV-C was investigated by analyzing the optically stimulated luminescence (OSL) and ther- mo-luminescence (TL) signal produced by ultraviolet light exposure at room temperature. It... The KCI:Eu2+ system response to UV-C was investigated by analyzing the optically stimulated luminescence (OSL) and ther- mo-luminescence (TL) signal produced by ultraviolet light exposure at room temperature. It was found that after UV-C irra.diation, OSL was produced on a wide band of visible wavelengths with decay time that varied by several orders of magnitude depending on the Eu2+ aggregation state. In spite of the low intensity of solar UV-C reaching the Earth's surface in Madrid (40° N, 700 m a.s.1.), it was possible to measure the UV-C radiation dose at 6:48 solar time by using the TL response of the KCI:Eu2+ system and differentiate it from the ambient beta radiation dose. 展开更多
关键词 THERMO-LUMINESCENCE rare-earth-doped alkali halides solar ultraviolet dosimeter environmental radiation
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Influences of UV-C Irradiation on Seed Germination and Seedling Growth of Winter Wheat
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作者 张晓晶 张思亮 +3 位作者 陆捷 杨晓燕 吕志伟 张文会 《Agricultural Science & Technology》 CAS 2013年第1期49-53,75,共6页
[Objective] This study aimed to investigate the influences of UV-C irradiation on seed germination and seedling growth of winter wheat. [Method] Winter wheat cul- tivar Liaoda 02 was selected as the experimental mater... [Objective] This study aimed to investigate the influences of UV-C irradiation on seed germination and seedling growth of winter wheat. [Method] Winter wheat cul- tivar Liaoda 02 was selected as the experimental material and irradiated with UV-C for 1 h,to compare the dynamic changes of seed germination rate under different treatment time and the changes of gibberellin (GA) content and a-amylase activity during the germination process after UV-C irradiation. Wheat seeds irradiated with UV-C for 1 h were sown, the emergence number, growth speed, fluorescence param- eter, reflectance spectrum, relative conductivity and other related physiological indica- tors of seedlings were determined. [Result] The results showed that the germination rate of dry and wet winter wheat seeds irradiated with UV-C for 1 h was improved, compared with the untreated seeds. After soaked for 6, 8, 10 and 12 h, dry seeds irradiated with UV-C for 1 h showed higher GA content and higher a-amylase activity than the control. In addition, UV-C-irradiated dry seeds also showed faster emergence speed and plant growth speed within the first six days after emergence and greater plant height than the control. The flavonoid content in leaves of the treatment group was also increased compared with the control, while the maximal photochemical effi- ciency (Fv/Fm), photo-chemical reflectance index (PRI), chlorophyll and carotenoid content were rarely influenced. In conclusion, UV-C irradiation could improve the ger- mination rate of dry seeds and wet seeds soaked for a certain time, especially for wet seeds soaked for 1 h. Furthermore, UV-C-irradiated seeds showed improved ger- mination speed and plant growth. [Conclusion] This study laid the foundation for ex- ploring the effect mechanism of ultraviolet rays on seed generation. 展开更多
关键词 uv-c Germination rate Wheat
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Attenuation of UV-C Solar Radiation as a Function of Altitude(0≤z≤100 km):Rayleigh Diffusion and Photo Dissociation of O_(2) Influence
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作者 Jose Luis Pinedo-Vega Carlos Rios-Martínez +5 位作者 David Jacobo Navarro-Solis J.Ignacio Davila-Rangel Fernando Mireles-Garcia Sonia Azucena Saucedo-Anaya Eduardo Manzanares-Acuna Valentin Badillo-Almaraz 《Atmospheric and Climate Sciences》 2017年第4期540-553,共14页
In this paper, we present an analysis of attenuation for UV-C radiation () as a function of the altitude z () by calculating the interaction ratio between the UV-C radiation and the molecular species susceptible of in... In this paper, we present an analysis of attenuation for UV-C radiation () as a function of the altitude z () by calculating the interaction ratio between the UV-C radiation and the molecular species susceptible of interact with UV-C radiation. The Rayleigh scattering spectral cross sections were calculated, the UV-C spectral cross sections of the species susceptible of interact with UV-C radiation and the UV extraterrestrial (ETR) solar spectrum were standardized with wavelength steps of 1 nm, and The International Standard Atmosphere model (ISO 1972) was adapted to calculate the molecular density. These data were utilized to calculate the photodissociation and Rayleigh scattering ratios as a function of the altitude and to determine to what measure the photodissociation and the Rayleigh diffusion were determinants of the attenuation of UV-C radiation. It became clear that the photo dissociation of O2 is the primordial mechanism of attenuation for the UV-C radiation, but the Rayleigh diffusion appears like a mechanism that encreases the photon flux, raising the performance of the O2 photodissociation. The attenuation capacities of N2O, CO2 and water vapor (H2O) over the UV-C radiation are all similar, although smaller (less than 0.6%), and this is due to their low concentration. The O3, has the theoretical greater attenuation capacity, but it is found in mid-range altitudes? (), where the residual UV-C photons has almost vanished by O2 photo dissociation or Rayleigh diffusion, so the real effect over the UV-C attenuation is minimum. 展开更多
关键词 uv-c radiation Rayleigh Scattering O_(2) Photodissociation
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Selective internal radiation therapy segmentectomy:A new minimally invasive curative option for primary liver malignancies? 被引量:2
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作者 Riccardo Inchingolo Francesco Cortese +5 位作者 Antonio Rosario Pisani Fabrizio Acquafredda Roberto Calbi Riccardo Memeo Fotis Anagnostopoulos Stavros Spiliopoulos 《World Journal of Gastroenterology》 SCIE CAS 2024年第18期2379-2386,共8页
Transarterial radioembolization or selective internal radiation therapy(SIRT)has emerged as a minimally invasive approach for the treatment of tumors.This percutaneous technique involves the local,intra-arterial deliv... Transarterial radioembolization or selective internal radiation therapy(SIRT)has emerged as a minimally invasive approach for the treatment of tumors.This percutaneous technique involves the local,intra-arterial delivery of radioactive microspheres directly into the tumor.Historically employed as a palliative measure for liver malignancies,SIRT has gained traction over the past decade as a potential curative option,mirroring the increasing role of radiation segmentectomy.The latest update of the BCLC hepatocellular carcinoma guidelines recognizes SIRT as an effective treatment modality comparable to other local ablative methods,particularly well-suited for patients where surgical resection or ablation is not feasible.Radiation segmentectomy is a more selective approach,aiming to deliver high-dose radiation to one to three specific hepatic segments,while minimizing damage to surrounding healthy tissue.Future research efforts in radiation segmentectomy should prioritize optimizing radiation dosimetry and refining the technique for super-selective administration of radiospheres within the designated hepatic segments. 展开更多
关键词 Transarterial radioembolization Selective internal radiation therapy radiation segmentectomy Hepatocellular carcinoma Primary liver malignancies Personalised dosimetry
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Failure mechanism and infrared radiation characteristic of hard siltstone induced by stratification effect 被引量:1
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作者 CHENG Yun SONG Zhanping +2 位作者 XU Zhiwei YANG Tengtian TIAN Xiaoxu 《Journal of Mountain Science》 SCIE CSCD 2024年第3期1058-1074,共17页
The deformation in sedimentary rock induced by train loads has potential threat to the safe operation of tunnels. This study investigated the influence of stratification structure on the infrared radiation and tempora... The deformation in sedimentary rock induced by train loads has potential threat to the safe operation of tunnels. This study investigated the influence of stratification structure on the infrared radiation and temporal damage mechanism of hard siltstone. The uniaxial compression tests, coupled with acoustic emission(AE) and infrared radiation temperature(IRT) were conducted on siltstones with different stratification effects. The results revealed that the stratigraphic structure significantly affects the stress-strain response and strength degradation characteristics. The mechanical parameters exhibit anisotropy characteristics, and the stratification effect exhibits a negative correlation with the cracking stress and peak stress. The failure modes caused by the stratification effect show remarkable anisotropic features, including splitting failure(Ⅰ: 0°-22.50°, Ⅱ: 90°), composite failure(45°), and shearing failure(67.50°). The AE temporal sequences demonstrate a stepwise response characteristic to the loading stress level. The AE intensity indicates that the stress sensitivity of shearing failure and composite failure is generally greater than that of splitting failure. The IRT field has spatiotemporal migration and progressive dissimilation with stress loading and its dissimilation degree increases under higher stress levels. The stronger the stratification effect, the greater the dissimilation degree of the IRT field. The abnormal characteristic points of average infrared radiation temperature(AIRT) variance at local stress drop and peak stress can be used as early and late precursors to identify fracture instability. Theoretical analysis shows that the competitive relationship between compaction strengthening and fracturing damage intensifies the dissimilation of the infrared thermal field for an increasing stress level. The present study provides a theoretical reference for disaster warnings in hard sedimentary rock mass. 展开更多
关键词 Hard siltstone Failure mechanism Stratification effect Infrared radiation characteristic Temporal-damage mechanism DISSIMILATION
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Simulation of the Ecosystem Productivity Responses to Aerosol Diffuse Radiation Fertilization Effects over the Pan-Arctic during 2001–19 被引量:1
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作者 Zhiding ZHANG Xu YUE +3 位作者 Hao ZHOU Jun ZHU Yadong LEI Chenguang TIAN 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第1期84-96,共13页
The pan-Arctic is confronted with air pollution transported from lower latitudes.Observations have shown that aerosols help increase plant photosynthesis through the diffuse radiation fertilization effects(DRFEs).Whil... The pan-Arctic is confronted with air pollution transported from lower latitudes.Observations have shown that aerosols help increase plant photosynthesis through the diffuse radiation fertilization effects(DRFEs).While such DRFEs have been explored at low to middle latitudes,the aerosol impacts on pan-Arctic ecosystems and the contributions by anthropogenic and natural emission sources remain less quantified.Here,we perform regional simulations at 0.2o×0.2ousing a well-validated vegetation model(Yale Interactive terrestrial Biosphere,YIBs)in combination with multi-source of observations to quantify the impacts of aerosol DRFEs on the net primary productivity(NPP)in the pan-Arctic during 2001-19.Results show that aerosol DRFEs increase pan-Arctic NPP by 2.19 Pg C(12.8%)yr^(-1)under clear-sky conditions,in which natural and anthropogenic sources contribute to 8.9% and 3.9%,respectively.Under all-sky conditions,such DRFEs are largely dampened by cloud to only 0.26 Pg C(1.24%)yr^(-1),with contributions of 0.65% by natural and 0.59% by anthropogenic species.Natural aerosols cause a positive NPP trend of 0.022% yr^(-1)following the increased fire activities in the pan-Arctic.In contrast,anthropogenic aerosols induce a negative trend of-0.01% yr^(-1)due to reduced emissions from the middle latitudes.Such trends in aerosol DRFEs show a turning point in the year of 2007 with more positive NPP trends by natural aerosols but negative NPP trends by anthropogenic aerosols thereafter.Though affected by modeling uncertainties,this study suggests a likely increasing impact of aerosols on terrestrial ecosystems in the pan-Arctic under global warming. 展开更多
关键词 diffuse radiation fertilization effects anthropogenic aerosols natural aerosols pan-Arctic net primary productivity
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High-speed performance self-powered short wave ultraviolet radiation detectors based onκ(ε)-Ga_(2)O_(3) 被引量:1
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作者 Aleksei Almaev Alexander Tsymbalov +5 位作者 Bogdan Kushnarev Vladimir Nikolaev Alexei Pechnikov Mikhail Scheglov Andrei Chikiryaka Petr Korusenko 《Journal of Semiconductors》 EI CAS CSCD 2024年第4期56-62,共7页
High-speed solar-blind short wavelength ultraviolet radiation detectors based onκ(ε)-Ga_(2)O_(3)layers with Pt contacts were demonstrated and their properties were studied in detail.Theκ(ε)-Ga_(2)O_(3)layers were ... High-speed solar-blind short wavelength ultraviolet radiation detectors based onκ(ε)-Ga_(2)O_(3)layers with Pt contacts were demonstrated and their properties were studied in detail.Theκ(ε)-Ga_(2)O_(3)layers were deposited by the halide vapor phase epitaxy on patterned GaN templates with sapphire substrates.The spectral dependencies of the photoelectric properties of struc-tures were analyzed in the wavelength interval 200-370 nm.The maximum photo to dark current ratio,responsivity,detectiv-ity and external quantum efficiency of structures were determined as:180.86 arb.un.,3.57 A/W,1.78×10^(12) Hz^(0.5)∙cm·W^(-1) and 2193.6%,respectively,at a wavelength of 200 nm and an applied voltage of 1 V.The enhancement of the photoresponse was caused by the decrease in the Schottky barrier at the Pt/κ(ε)-Ga_(2)O_(3)interface under ultraviolet exposure.The detectors demon-strated could functionalize in self-powered mode due to built-in electric field at the Pt/κ(ε)-Ga_(2)O_(3)interface.The responsivity and external quantum efficiency of the structures at a wavelength of 254 nm and zero applied voltage were 0.9 mA/W and 0.46%,respectively.The rise and decay times in self-powered mode did not exceed 100 ms. 展开更多
关键词 κ(ε)-gallium oxide solar-blind shortwave ultraviolet radiation detectors self-powered operation mode
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Effect of Postharvest UV-C Irradiation on Phenolic Compound Content and Antioxidant Activity of Tomato Fruit During Storage 被引量:15
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作者 LIU Chang-hong CAI Lu-yun +2 位作者 LU Xian-ying HAN Xiao-xu YING Tie-jin 《Journal of Integrative Agriculture》 SCIE CSCD 2012年第1期159-165,共7页
Mature-green tomato fruit (Solanum lycopersicum cv. Zhenfen 202) were exposed to different UV-C irradiation at 2, 4, 8, and 16 kJ m-2 and then stored under the dark at 14°C and 95% relative humidity (RH) for ... Mature-green tomato fruit (Solanum lycopersicum cv. Zhenfen 202) were exposed to different UV-C irradiation at 2, 4, 8, and 16 kJ m-2 and then stored under the dark at 14°C and 95% relative humidity (RH) for 35 d. Of these four doses, UV-C irradiation at 4 and 8 kJ m-2 significantly increased total phenolic contents in present tomato fruit by 21.2 and 20.2%, respectively. Furthermore, UV-C irradiation at 4 or 8 kJ m-2 promoted the accumulation of total flavonoids and increased the antioxidant activity. 2 or 16 kJ m-2 UV-C irradiation also enhanced antioxidant activity, but to a lesser extent. Seven phenolic compounds, viz., gallic acid, (+)-catechin, chlorogenic acid, cafferic acid, syringic acid, p-coumaric acid, and quercetin in tomato fruit were identified and quantified by HPLC. Gallic acid was the major phenolic compound in tomato fruit and significantly correlated with antioxidant activity. 4 or 8 kJ m-2 UV-C irradiation significantly increased the contents of gallic acid, chlorogenic acid, syringic acid, p-coumaric acid, and quercetin. The optimum dose of UV-C irradiation in terms of increased phenolic compound content and enhanced Antioxidant activity was determined to be 4 or 8 kJ m-2. 展开更多
关键词 TOMATO postharvest uv-c irradiation STORAGE antioxidant activity phenolic compounds
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Unraveling the efficacy network: A network meta-analysis of adjuvant external beam radiation therapy methods after hepatectomy 被引量:1
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作者 Gao-Yuan Yang Zhi-Wei He +7 位作者 Yong-Chang Tang Feng Yuan Ming-Bo Cao Yu-Peng Ren Yu-Xuan Li Xiao-Rui Su Zhi-Cheng Yao Mei-Hai Deng 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第1期205-214,共10页
BACKGROUND Primary liver cancer is a malignant tumor with a high recurrence rate that significantly affects patient prognosis.Postoperative adjuvant external radiation therapy(RT)has been shown to effectively prevent ... BACKGROUND Primary liver cancer is a malignant tumor with a high recurrence rate that significantly affects patient prognosis.Postoperative adjuvant external radiation therapy(RT)has been shown to effectively prevent recurrence after liver cancer resection.However,there are multiple RT techniques available,and the differ-ential effects of these techniques in preventing postoperative liver cancer re-currence require further investigation.AIM To assess the advantages and disadvantages of various adjuvant external RT methods after liver resection based on overall survival(OS)and disease-free survival(DFS)and to determine the optimal strategy.METHODS This study involved network meta-analyses and followed the PRISMA guidelines.The data of qualified studies published before July 10,2023,were collected from PubMed,Embase,the Web of Science,and the Cochrane Library.We included relevant studies on postoperative external beam RT after liver resection that had OS and DFS as the primary endpoints.The magnitudes of the effects were determined using risk ratios with 95%confidential intervals.The results were analyzed using R software and STATA software.RESULTS A total of 12 studies,including 1265 patients with hepatocellular carcinoma(HCC)after liver resection,were included in this study.There was no significant heterogeneity in the direct paired comparisons,and there were no significant differences in the inclusion or exclusion criteria,intervention measures,or outcome indicators,meeting the assumptions of heterogeneity and transitivity.OS analysis revealed that patients who underwent stereotactic body radiotherapy(SBRT)after resection had longer OS than those who underwent intensity modulated radiotherapy(IMRT)or 3-dimensional conformal RT(3D-CRT).DFS analysis revealed that patients who underwent 3D-CRT after resection had the longest DFS.Patients who underwent IMRT after resection had longer OS than those who underwent 3D-CRT and longer DFS than those who underwent SBRT.CONCLUSION HCC patients who undergo liver cancer resection must consider distinct advantages and disadvantages when choosing between SBRT and 3D-CRT.IMRT,a RT technique that is associated with longer OS than 3D-CRT and longer DFS than SBRT,may be a preferred option. 展开更多
关键词 Primary liver cancer Hepatocellular carcinoma Network meta-analysis External beam radiation therapy Stereotactic body radiotherapy Intensity modulated radiotherapy
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Radiation of a TM mode from an open end of a three-layer dielectric capillary
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作者 Sergey NGalyamin Alexandr MAltmark 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第7期311-318,共8页
Modern trends in beam-driven radiation sources include the interaction of Cherenkov wakefields in open-ended circular waveguides with complicated dielectric linings, with a three-layer dielectric capillary recently pr... Modern trends in beam-driven radiation sources include the interaction of Cherenkov wakefields in open-ended circular waveguides with complicated dielectric linings, with a three-layer dielectric capillary recently proposed to reduce radiation divergence being a representative example [Opt. Lett. 45 5416(2020)]. We present a rigorous approach that allows for an analytical description of the electromagnetic processes that occur when the structure is excited by a single waveguide TM mode. In other words, the corresponding canonical waveguide diffraction problem is solved in a rigorous formulation. This is a continuation of our previous papers which considered simpler cases with a homogeneous or two-layer dielectric filling. Here we use the same analytical approach based on the Wiener–Hopf–Fock technique and deal with the more complicated case of a three-layer dielectric lining. Using the obtained rigorous solution, we discuss the possibility of manipulating the far-field radiation pattern using a third layer made of a low permittivity material. 展开更多
关键词 diffraction radiation open-ended waveguide Wiener–Hopf technique Cherenkov radiation
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Flexibility potential of Cs_(2)BX_(6)(B=Hf,Sn,Pt,Zr,Ti;X=I,Br,Cl)with application in photovoltaic devices and radiation detectors
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作者 Songya Wang Changcheng Chen +11 位作者 Shaohang Shi Ziyi Zhang Yan Cai Shuli Gao Wen Chen Shuangna Guo Elyas Abduryim Chao Dong Xiaoning Guan Ying Liu Gang Liu Pengfei Lu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第8期271-287,I0006,共18页
As interest in double perovskites is growing,especially in applications like photovoltaic devices,understanding their mechanical properties is vital for device durability.Despite extensive exploration of structure and... As interest in double perovskites is growing,especially in applications like photovoltaic devices,understanding their mechanical properties is vital for device durability.Despite extensive exploration of structure and optical properties,research on mechanical aspects is limited.This article builds a vacancyordered double perovskite model,employing first-principles calculations to analyze mechanical,bonding,electronic,and optical properties.Results show Cs_(2)Hfl_(6),Cs_(2)SnBr_(6),Cs_(2)SnI_(6),and Cs_(2)PtBr_(6)have Young's moduli below 13 GPa,indicating flexibility.Geometric parameters explain flexibility variations with the changes of B and X site composition.Bonding characteristic exploration reveals the influence of B and X site electronegativity on mechanical strength.Cs_(2)SnBr_(6)and Cs_(2)PtBr_(6)are suitable for solar cells,while Cs_(2)HfI_(6)and Cs_(2)TiCl_(6)show potential for semi-transparent solar cells.Optical property calculations highlight the high light absorption coefficients of up to 3.5×10^(5) cm^(-1)for Cs_(2)HfI_(6)and Cs_(2)TiCl_(6).Solar cell simulation shows Cs_(2)PtBr_(6)achieves 22.4%of conversion effciency.Cs_(2)ZrCl_(6)holds promise for ionizing radiation detection with its 3.68 eV bandgap and high absorption coefficient.Vacancy-ordered double perovskites offer superior flexibility,providing valuable insights for designing stable and flexible devices.This understanding enhances the development of functional devices based on these perovskites,especially for applications requiring high stability and flexibility. 展开更多
关键词 Double perovskite Mechanical properties Flexible PHOTOVOLTAIC radiation detectors
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Visualizing the Spin & Radiation of the Extended Electron in Magnetic Field
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作者 Hoa Van Nguyen 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2024年第1期277-291,共15页
This article presents illustrations of an extended model of the electron to visualize how it spins and radiates in the external magnetic field. A time-varying magnetic field B produces a rotational induced electric fi... This article presents illustrations of an extended model of the electron to visualize how it spins and radiates in the external magnetic field. A time-varying magnetic field B produces a rotational induced electric field E which rotates (spins) the electron about its axis. In time-constant magnetic field: the electron radiates the cyclotron radiation. In time-varying magnetic field: synchrotron radiation is generated. The couplings between spin, acceleration and radiation will be discussed. 展开更多
关键词 Spinning Forces Spin by Inertia radiating Forces Photon or Static Electric Dipole Cloud of Photons Spin - radiation Coupling
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Heuristic Estimation of the Vacuum Energy Density of the Universe: Part II-Analysis Based on Frequency Domain Electromagnetic Radiation
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作者 Vernon Cooray Gerald Cooray +1 位作者 Marcos Rubinstein Farhad Rachidi 《Journal of Electromagnetic Analysis and Applications》 2024年第1期1-9,共9页
In Part I of this paper, an inequality satisfied by the vacuum energy density of the universe was derived using an indirect and heuristic procedure. The derivation is based on a proposed thought experiment, according ... In Part I of this paper, an inequality satisfied by the vacuum energy density of the universe was derived using an indirect and heuristic procedure. The derivation is based on a proposed thought experiment, according to which an electron is accelerated to a constant and relativistic speed at a distance L from a perfectly conducting plane. The charge of the electron was represented by a spherical charge distribution located within the Compton wavelength of the electron. Subsequently, the electron is incident on the perfect conductor giving rise to transition radiation. The energy associated with the transition radiation depends on the parameter L. It was shown that an inequality satisfied by the vacuum energy density will emerge when the length L is pushed to cosmological dimensions and the product of the radiated energy, and the time duration of emission is constrained by Heisenberg’s uncertainty principle. In this paper, a similar analysis is conducted with a chain of electrons oscillating sinusoidally and located above a conducting plane. In the thought experiment presented in this paper, the behavior of the energy radiated by the chain of oscillating electrons is studied in the frequency domain as a function of the length L of the chain. It is shown that when the length L is pushed to cosmological dimensions and the energy radiated within a single burst of duration of half a period of oscillation is constrained by the fact that electromagnetic energy consists of photons, an inequality satisfied by the vacuum energy density emerges as a result. The derived inequality is given by where is the vacuum energy density. This result is consistent with the measured value of the vacuum energy density, which is 5.38 × 10<sup>-10</sup> J/m. The result obtained here is in better agreement with experimental data than the one obtained in Part I of this paper with time domain radiation. 展开更多
关键词 Classical Electrodynamics Electromagnetic radiation Action radiated Energy PHOTON Heisenberg’s Uncertainty Principle Dark Energy Vacuum Energy Cosmological Constant Hubble Radius
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Progress of Radiation Belt Exploration by a Constellation of Small Satellites TGCSS/SGRB, COSPAR
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作者 WU Ji YANG Xiaochao +1 位作者 DAI Lei DENG Li 《空间科学学报》 CAS CSCD 北大核心 2024年第4期746-750,共5页
A COnstellation of Radiation BElt Survey(CORBES)program is proposed by the Sub-Group on Radiation Belt(SGRB)of TGCSS,COSPAR.To address the open qustions about the dynamics of the Earth’s radiation belt,CORBES mission... A COnstellation of Radiation BElt Survey(CORBES)program is proposed by the Sub-Group on Radiation Belt(SGRB)of TGCSS,COSPAR.To address the open qustions about the dynamics of the Earth’s radiation belt,CORBES mission would use a constellation of small/CubeSats to take an ultra-fast survey of the Earth’s radiation belt.The concept,science objectives and preliminary technical design of CORBES are introduced.This mission is an international multilateral cooperation mission coordinated by COSPAR.The SGRB Science Activities and COSPAR HQs Coordinate Activities on CORBES are summaried. 展开更多
关键词 radiation belts Ultra-fast survey CONSTELLATION
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The Effect of a Monatomic Layer on a Surface on the Transition Radiation
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作者 Alexander N. Safronov 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2024年第2期710-723,共14页
The transition radiation of a charged particle crossing the interface of two media having a monatomic impurity layer is investigated. It is shown that at sliding angles of incidence of a particle on the boundary of th... The transition radiation of a charged particle crossing the interface of two media having a monatomic impurity layer is investigated. It is shown that at sliding angles of incidence of a particle on the boundary of the media, the transition radiation is mainly determined by the properties of the surface layer. The possibility of using transition radiation to study the surface of substances is discussed. In addition, due to the hard radiation present in space, this research may be important for the use of light monoatomic layers as a material for satellite antennas, “solar sails” and cover layers in a future space (interstellar) mission. 展开更多
关键词 Relativistic Charged Particle Transition radiation Monatomic Layer Spectral Angular Distribution of radiation Sliding Angle Investigation of Thin Films Interstellar Mission
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Operando measurement of lattice deformation profiles of synchrotron radiation monochromator
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作者 Yue Zhang Zhong-Liang Li +4 位作者 Shang-Yu Si Lian Xue Hong-Xin Luo Xiao-Wei Zhang Jun Hu 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第7期8-19,共12页
This study presents a new method for characterizing the thermal lattice deformation of a monochromator with high precision under service conditions and first reports the operando measurements of nanoscale thermal latt... This study presents a new method for characterizing the thermal lattice deformation of a monochromator with high precision under service conditions and first reports the operando measurements of nanoscale thermal lattice deformation on a double-crystal monochromator at different incident powers.The nanoscale thermal lattice deformation of the monochromator first crystal was obtained by analyzing the intensity of the distorted DuMond diagrams.DuMond diagrams of the 333 diffraction index,sensitive to lattice deformation,were obtained directly using a 2D detector and an analyzer crystal orthogonal to the monochromator.With increasing incident power and power density,the maximum height of the lattice deformation increased from 3.2 to 18.5 nm,and the deformation coefficient of the maximum height increased from 1.1 to 3.2 nm/W.The maximum relative standard deviation was 4.2%,and the maximum standard deviation was 0.1 nm.Based on the measured thermal deformations,the flux saturation phenomenon and critical point for the linear operation of the monochromator were predicted with increasing incident power.This study provides a simple solution to the problem of the lower precision of synchrotron radiation monochromator characterizations compared to simulations. 展开更多
关键词 Synchrotron radiation MONOCHROMATOR Lattice deformation X-ray dynamic diffraction
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Experimental investigation of spectral evolution in flash radiation by hypervelocity impact on aluminum plates
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作者 Xing Chen Yonggang Lu +1 位作者 Zhiwen Li Zhonghua Cui 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第7期96-110,共15页
In this study,a series of hypervelocity impact tests were carried out based on a two-stage light gas gun,and the sequence spectrum and radiation evolution data of the impact products under different impact conditions ... In this study,a series of hypervelocity impact tests were carried out based on a two-stage light gas gun,and the sequence spectrum and radiation evolution data of the impact products under different impact conditions were obtained.The diameter of the projectile is 3-5 mm,the impact velocity is 3.13-6.58 km/s,and the chamber pressure is 0.56-990 Pa.The spectrum of ejected debris cloud in the 250-310 nm band were obtained using a transient spectral measurement system and a multi-channel radiometer measurement system.The test results reveal that the flash radiation intensity increases as a power function with the kinetic energy of the impact.Furthermore,the peak value of the line spectrum decreases as the chamber vacuum degree increases,while the radiation width gradually expands.The line spectrum in the spectral characterization curve corresponds to the ejected debris clouds splitting phase,which does not produce significant line spectrum during material fragmentation and is dominated by the continuum spectrum produced by blackbody radiation.There will appear one or three characteristic peaks in the flash radiation time curve,the first and second peaks correspond to the penetration phase and the third peak corresponds to the expansion phase of the ejected debris clouds on the time scale,the first and second peaks are more sensitive to the chamber vacuum degree,and when the pressure is higher than 99 Pa,the first and second characteristic peaks will disappear.The radiant heat attenuation of the flash under different impact conditions is significantly different,the attenuation exponent has a power function relationship with the impact velocity and the chamber vacuum degree,while the attenuation exponent has a linear relationship with the diameter of the projectile,the specific expression of the attenuation exponent is obtained by fitting.The findings from this research can serve as a valuable reference for remote diagnostic technologies based on flash radiation characteristics. 展开更多
关键词 Hypervelocity impact Flash radiation EVOLUTION Spectral characteristics Damage evaluation
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Assessing the yield difference of double-cropping rice in South China driven by radiation use efficiency
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作者 Jian Lu Sicheng Deng +6 位作者 Muhammad Imran Jingyin Xie Yuanyuan Li Jianying Qi Shenggang Pan Xiangru Tang Meiyang Duan 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第11期3692-3705,共14页
Double-cropping rice in South China continues to break the total yield record,but the yield potential of singlecropping rice is not being realized.Radiation use efficiency(RUE)has been singled out as an important dete... Double-cropping rice in South China continues to break the total yield record,but the yield potential of singlecropping rice is not being realized.Radiation use efficiency(RUE)has been singled out as an important determinant of grain yield in many cereal species.However,there is no information on whether the yield gaps in doublecropping rice involve differences in RUE.Field experiments were performed over two years to evaluate the effects of intercepted radiation(IP)and RUE on the above-ground biomass production,crop growth rate(CGR),and harvest index(HI),in four representative rice varieties,i.e.,Xiangyaxiangzhan(XYXZ),Meixiangzhan 2(MXZ2),Nanjingxiangzhan(NJXZ),and Ruanhuayoujinsi(RHYJS),during the early and late seasons of rice cultivation in South China.The results revealed that grain yield in the early season was 8.2%higher than in the late season.The yield advantage in the early season was primarily due to higher spikelets per panicle and above-ground biomass resulting from a higher RUE.The spikelets per panicle in the early season were 6.5,8.3,6.9,and 8.5%higher in XYXZ,MXZ2,NJXZ,and RHYJS,respectively,than in the late season.The higher early season grain yield was more closely related to RUE in the middle tillering stage(R^(2)=0.34),panicle initiation(R^(2)=0.16),and maturation stage(R^(2)=0.28),and the intercepted photosynthetically active radiation(IPAR)in the maturation stage(R^(2)=0.28),while the late season grain yield was more dependent on IPAR in the middle tillering stage(R^(2)=0.31)and IPAR at panicle initiation(R^(2)=0.23).The results of this study conclusively show that higher RUE contributes to the yield progress of early season rice,while the yield improvement of late season rice is attributed to higher radiation during the early reproductive stage.Rationally allocating the RUE of double-cropping rice with high RUE varieties or adjustments of the sowing period merits further study. 展开更多
关键词 grain yield radiation use efficiency double-cropping rice
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Extraction of the key infrared radiation temperature features concerning stress and crack evolution of loaded rocks
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作者 Wei Liu Liqiang Ma +4 位作者 Michel Jaboyedoff Marc-Henri Derron Qiangqiang Gao Fengchang Bu Hai Sun 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第8期1059-1081,共23页
The infrared radiation temperature(IRT)variation concerning stress and crack evolution of rocks is a critical focus in rock mechanics domain and engineering disaster warning.In this paper,a methodology to extract the ... The infrared radiation temperature(IRT)variation concerning stress and crack evolution of rocks is a critical focus in rock mechanics domain and engineering disaster warning.In this paper,a methodology to extract the key IRT features related to stress and crack evolution of loaded rocks is proposed.Specifically,the wavelet denoising and reconstruction in thermal image sequence(WDRTIS)method is employed to eliminate temporal noise in thermal image sequences.Subsequently,the adaptive partition temperature drift correction(APTDC)method is introduced to alleviate temperature drift.On this basis,the spatial noise correction method based on threshold segmentation and adaptive median filtering(OTSU-AMF)is proposed to extract the key IRT features associated with microcracks of loaded rocks.Following temperature drift correction,IRT provides an estimation of the thermoelastic factor in rocks,typically around 5.29×10^(-5) MPa^(-1) for sandstones.Results reveal that the high-temperature concentrated region in cumulative thermal images of crack evolution(TICE)can elucidate the spatiotemporal evolution of localized damage.Additionally,heat dissipation of crack evolution(HDCE)acquired from TICE quantifies the progressive failure process of rocks.The proposed methodology enhances the reliability of IRT monitoring results and provides an innovative approach for conducting research in rock mechanics and monitoring engineering disasters. 展开更多
关键词 Infrared radiation(IR) Temperature drift Spatial background noise Rock fracture Average infrared radiation temperature(AIRT) Heat dissipation of crack evolution(HDCE)
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