To investigate the DNA polymorphism of M2 plants of Lotus japonicus induced by heavy ion beam, dry seeds were irradiated by carbon ion beams accelerated by Heavy Ion Research Facility in Lanzhou (HIRFL). Inter simple ...To investigate the DNA polymorphism of M2 plants of Lotus japonicus induced by heavy ion beam, dry seeds were irradiated by carbon ion beams accelerated by Heavy Ion Research Facility in Lanzhou (HIRFL). Inter simple sequence repeat (ISSR) assay were utilized to explore the DNA variation of M2 plants irradiated by 400 Gy carbon ion beams. ISSR technique is an effective molecular marker method based on polymerase chain reaction amplification of template DNA by a single primer with 1626 bp[1]. ISSR can detect the differences of genetic structure of various life materials rapidly.展开更多
Arabidopsis thaliana is one of the most commonly used model plants due to its short life cycle and concise genome.As a novel physical mutagen, heavy ion beams have been widely used in plant breeding. The most signific...Arabidopsis thaliana is one of the most commonly used model plants due to its short life cycle and concise genome.As a novel physical mutagen, heavy ion beams have been widely used in plant breeding. The most significant advantages of heavy ion beams are the higher linear energy transfer (LET) and relative biological effectiveness (RBE), inducing a broad spectrum of mutation phenotypes even at low irradiation[1]. In order to investigate the effects on DNA behavior of Arabidopsis thaliana mutants induced by carbon ion irradiations, inter-simple sequence repeat (ISSR), a DNA-based molecular marker technique, was performed to assess the genetic polymorphism.展开更多
In this paper, two microwave irradiation methods：（i） liquid-phase microwave irradiation（MWI） reduction of graphite oxide suspension dissolved in de-ionized water and N, N-dimethylformamide, respectively, and（ii...In this paper, two microwave irradiation methods：（i） liquid-phase microwave irradiation（MWI） reduction of graphite oxide suspension dissolved in de-ionized water and N, N-dimethylformamide, respectively, and（ii） solid-phase MWI reduction of graphite oxide powder have been successfully carried out to reduce graphite oxide. The reduced graphene oxide products are thoroughly characterized by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectral analysis, Raman spectroscopy, UV-Vis absorption spectral analysis,and four-point probe conductivity measurements. The results show that both methods can efficiently remove the oxygencontaining functional groups attached to the graphite layers, though the solid-phase MWI reduction method can obtain far more efficiently a higher quality-reduced graphene oxide with fewer defects. The I（D）/I（G） ratio of the solid-phase MWI sample is as low as 0.46, which is only half of that of the liquid-phase MWI samples. The electrical conductivity of the reduced graphene oxide by the solid method reaches 747.9 S/m, which is about 25 times higher than that made by the liquid-phase method.展开更多
Swift heavy ions in matter lose energy mainly through electronic processes.Since the energy deposition is centered in a very small region with a very high energy density,new effects such as production of alkyne end gr...Swift heavy ions in matter lose energy mainly through electronic processes.Since the energy deposition is centered in a very small region with a very high energy density,new effects such as production of alkyne end group can be induced.In this work,PET,PS,PC and PI films are irradiated with Ar,Kr,Xe and U ions and the relationship of the alkyne end group production with electronic energy loss is studied by Fourier transformed infrared infrared(FTLR)spectra measurements.展开更多
In our previous work~[1],we have studied photoluminescence(PL)from 5.0×10^(17) C-ions/cm^2 doped SiO_2 films after 335 and 855 MeV^(40)Ar or 1.98 GeV^(84)Kr ion irradiations.It was found that PL bands centred at...In our previous work~[1],we have studied photoluminescence(PL)from 5.0×10^(17) C-ions/cm^2 doped SiO_2 films after 335 and 855 MeV^(40)Ar or 1.98 GeV^(84)Kr ion irradiations.It was found that PL bands centred at～430nm and～380 nm were formed in the C-doped SiO_2 films and the PL intensity decreases with electronic energy loss S_e increasing.In the present work,we studied the PL properties of C-doped SiO_2 films after 1.75 GeV Xe and 2.71 GeV U ion irradiations.展开更多
Ion irradiation of polymers can induce irreversible changes in their macroscopic propcrties.Electronic excitation,ionization,chains scission and cross-links as well as mass losses are acccpted as the fundamental event...Ion irradiation of polymers can induce irreversible changes in their macroscopic propcrties.Electronic excitation,ionization,chains scission and cross-links as well as mass losses are acccpted as the fundamental events that givc rise to the observed macroscopic changes.In this work PET films were irradiated with high-展开更多
Background: The skin serves as the first line of defense for the human body. Direct sunlight contains damaging radiations that can speed up the ageing process of the skin, resulting in wrinkles, leathery skin, dark pa...Background: The skin serves as the first line of defense for the human body. Direct sunlight contains damaging radiations that can speed up the ageing process of the skin, resulting in wrinkles, leathery skin, dark patches, and solar elastosis. Objectives: To evaluate the effect of multiple solar irradiation related factors at the protein level in human dermal fibroblast (HDF). The overall effect of individual solar irradiations such as Infrared A (IRA), blue light (BL), UVA, and UVB on HDF cells and the extent of molecular level aberrations to be assessed and compared against each. Methods: Label-free quantitative proteomics (MS/MS) approach has been adopted in this study to observe the protein level changes induced in the HDF cells through various exposures of full light sources. Following that, downstream insilico analysis has been carried out. Results: In this study, it is demonstrated all the four different solar irradiations significantly contribute to the molecular degeneration of skin cells through various mechanisms. This study confirms that BL down-regulates DNA repair proteins and the skin cells-HDF stimulate the histone proteins as a response mechanism to maintain the chromosomal integrity. Conclusions: The proteomics experiment carried out in the current study intends to support the future sun care products based on full light protection technology that can be custom designed to provide complete protection from the solar radiation. Similar technology could enhance the further investigations for deeper understanding of induction, mode of action, and prevention of skin damage from extensive solar irradiation.展开更多
We studied the oxygen etching of individual single-walled carbon nanotubes on silicon oxide substrates using atomic force microscopy and high-temperature environmental scanning electron microscopy. Our in situ observa...We studied the oxygen etching of individual single-walled carbon nanotubes on silicon oxide substrates using atomic force microscopy and high-temperature environmental scanning electron microscopy. Our in situ observations show that carbon nanotubes are not progressively etched from their ends, as frequently assumed, but disappear segment by segment. Atomic force microscopy, before and after oxidation, reveals that the oxidation of carbon nanotubes on substrates proceeds through a local cutting that is followed by a rapid etching of the disconnected nanotube segment. Unexpectedly, semiconducting nanotubes appear more reactive under these conditions than metallic ones. We also show that exposure to electron and laser beams locally increases the chemical reactivity of carbon nanotubes on such substrates. These results are rationalized by considering the effect of substrate-trapped charges on the nanotube density of states close to the Fermi level, which is impacted by the substrate type and the exposure to electron and laser beams.展开更多
This work presents a systematic analysis of proton-induced total ionizing dose(TID)effects in 1.2 k V silicon carbide(SiC)power devices with various edge termination structures.Three edge terminations including ring-a...This work presents a systematic analysis of proton-induced total ionizing dose(TID)effects in 1.2 k V silicon carbide(SiC)power devices with various edge termination structures.Three edge terminations including ring-assisted junction termination extension(RA-JTE),multiple floating zone JTE(MFZ-JTE),and field limiting rings(FLR)were fabricated and irradiated with45 Me V protons at fluences ranging from 1×10^(12) to 1×10^(14) cm^(-2).Experimental results,supported by TCAD simulations,show that the RA-JTE structure maintained stable breakdown performance with less than 1%variation due to its effective electric field redistribution by multiple P+rings.In contrast,MFZ-JTE and FLR exhibit breakdown voltage shifts of 6.1%and 15.2%,respectively,under the highest fluence.These results demonstrate the superior radiation tolerance of the RA-JTE structure under TID conditions and provide practical design guidance for radiation-hardened Si C power devices in space and other highradiation environments.展开更多
In this study,the dosimetric characteristics(thickness applicability,preheating time,temperature and humidity dependence,in-batch uniformity,readout reproducibility,dose linearity,self-decay,and electron energy respon...In this study,the dosimetric characteristics(thickness applicability,preheating time,temperature and humidity dependence,in-batch uniformity,readout reproducibility,dose linearity,self-decay,and electron energy response)of engineered polycarbonate films irradiated with an electron beam(0–600 kGy)were investigated using photoluminescence spectroscopy.The results show a linear relationship between photoluminescence intensity and radiation dose when the thickness of the polycarbonate film is 0.3 mm.A higher fluorescence intensity can be obtained by preheating at 60℃ for 180 min before photoluminescence spectrum analysis.As the temperature during spectral testing and the ambient humidity(during and after irradiation)increased,the photoluminescence intensity of the polycarbonate films decreased.The photoluminescence intensity deviation of the polycarbonate films produced within the same batch at 100 kGy is 2.73%.After ten times of repeated excitations and readouts,the coefficients of variation in photoluminescence intensity are less than 8.6%,and the linear correlation coefficient between photoluminescence intensity and irradiation dose is 0.965 in the dose capture range of 20–600 kGy.Within 60 days of irradiation,the photoluminescence intensity of the polycarbonate film decreased to 60%of the initial value.The response of the 0.3 mm polycarbonate films to electron beams with energies exceeding 3.5 MeV does not differ significantly.This comprehensive analysis indicates the potential of polycarbonate films as a high-radiation dose detection material.展开更多
The most amazing chemistry is the light-driven water splitting reaction occurred in the oxygen-evolving complex of phototsystem II in higher plants, green algae, and cyanobacteria. Mn, in the form of Mn4CaOs cluster i...The most amazing chemistry is the light-driven water splitting reaction occurred in the oxygen-evolving complex of phototsystem II in higher plants, green algae, and cyanobacteria. Mn, in the form of Mn4CaOs cluster in photosystem II, is responsible for the catalytic water splitting reaction as well as plays roles in photosystem II dynamics to irradiation and temperatures. Manganese hypothesis of UV-initiated photoinhibition as a direct target is established, and thermal inactivation of photosystem II involves the valence and structural changes of manganese. Recent progresses in understanding the roles of manganese in photoinhibition especially under UV light and in thermal inactivation including elevated temperatures using synthetic models and native PS II complexes are summarized and evaluated. Potential problems and possible solutions are discussed and presented.展开更多
Thermally grown amorphous SiO2 films were implanted at room temperature with 100 keV C-ions to 5.0× 10^17 or 1.2× 10^18 ions/cm2. These samples were irradiated at room temperature with 853 MeV Pb-ions to 5.0...Thermally grown amorphous SiO2 films were implanted at room temperature with 100 keV C-ions to 5.0× 10^17 or 1.2× 10^18 ions/cm2. These samples were irradiated at room temperature with 853 MeV Pb-ions to 5.0× 10^11, 1.0× 10^12, 5.0× 10^12 ions/cm2, or with 308 MeV Xe-ions to 1.0× 10^12, 1.0× 10^13, 1.0× 10^14 ions/cm2, respectively. Then the samples were investigated using micro-Raman spectroscopy. Prom the obtained Raman spectra, we deduced that Si-C bonds and sp2 carbon sites were created and nano-inclusions may also be produced in the heavy ion irradiated C-doped SiO2. Furthermore, some results show that Pb ion irradiations could produce larger size inclusions than Xe ions and the fluence. The possible modification process of C-doped discussed. inclusion size decreased with increasing the irradiation a-SiO2 under swift heavy ion irradiations was briefly展开更多
The removal of ammonia nitrogen(NH_(4)^(+)-N)and bacteria from aquaculture wastewater holds paramount ecological and production significance.In this study,Pt/RuO_(2)/g-C_(3)N_(4)photocatalysts were prepared by deposit...The removal of ammonia nitrogen(NH_(4)^(+)-N)and bacteria from aquaculture wastewater holds paramount ecological and production significance.In this study,Pt/RuO_(2)/g-C_(3)N_(4)photocatalysts were prepared by depositing Pt and RuO_(2)particles onto g-C_(3)N_(4).The physicochemical properties of photocatalysts were explored by X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),X-ray diffraction(XRD),and UV–vis diffuse reflectance spectrometer(UV–vis DRS).The photocatalysts were then applied to the removal of both NH_(4)^(+)-N and bacteria from simulated mariculture wastewater.The results clarified that the removals of both NH_(4)^(+)-N and bacteria were in the sequence of g-C_(3)N_(4)<RuO_(2)/g-C_(3)N_(4)<Pt/g-C_(3)N_(4)<Pt/RuO_(2)/g-C_(3)N_(4).This magnificent photocatalytic ability of Pt/RuO_(2)/g-C_(3)N_(4)can be interpreted by the transfer of holes from g-C_(3)N_(4)to RuO_(2)to facilitate the in situ generation of HClO from Cl^(−)in wastewater,while Pt extracts photogenerated electrons for H_(2)formation to enhance the reaction.The removal of NH_(4)^(+)-N and disinfection effect were more pronounced in simulated seawater than in purewater.The removal efficiency ofNH_(4)^(+)-N increases with an increase in pH of wastewater,while the bactericidal effect was more significant under a lower pH in a pH range of 6–9.In actual seawater aquaculture wastewater,Pt/RuO_(2)/g-C_(3)N_(4)still exhibits effective removal efficiency of NH_(4)^(+)-N and bactericidal performance under sunlight.This study provides an alternative avenue for removement of NH_(4)^(+)-N and bacteria from saline waters under sunlight.展开更多
The Mg alloys with combination of high strength and excellent irradiation resistance are currently re-quired for research reactors.In this work,the novel Mg-3Mn-0.5Ca alloy with a high strength of over 300 MPa has bee...The Mg alloys with combination of high strength and excellent irradiation resistance are currently re-quired for research reactors.In this work,the novel Mg-3Mn-0.5Ca alloy with a high strength of over 300 MPa has been fabricated via co-addition of Mn and Ca elements.Moreover,the Xe ion implantation(300℃/4.5×10^(15)ions/cm^(2))is conducted for pure Mg,Mg-3Mn and Mg-3Mn-0.5Ca alloys.Microstruc-ture characterization shows that the number density of dislocation loops is comparable between Mg-3Mn and pure Mg,while the phase boundary of nano-Mn particles could act as the sink to absorb more Xe atoms,resulting in the abundant formation of Xe bubbles in the matrix of irradiated Mg-3Mn alloy.With further minor addition of Ca element,the formation of Xe bubbles and dislocation loops in Mg-3Mn-0.5Ca alloy has been obviously suppressed,and the abundant grain boundaries(GBs)due to grain refinement then act as the sink region for Xe precipitation.The limited number density of Xe bubbles leads to the extremely low swelling ratio in Mg-3Mn-0.5Ca alloy,∼0.08%.The result above suggests that the Mn and Ca co-addition could enhance the mechanical properties and irradiation tolerance of Mg alloys,si-multaneously.The present low-alloying strategy would provide a new design reference for novel nuclear materials.展开更多
Establishing Consensus with Users of Research Irradiator Devices to Facilitate Source Type Replacement Danette R.Fennesy1,Janet M.Gutiérrez1,2,Scott J.Patlovich1,Robert J.Emery1(1.The University of Texas Health S...Establishing Consensus with Users of Research Irradiator Devices to Facilitate Source Type Replacement Danette R.Fennesy1,Janet M.Gutiérrez1,2,Scott J.Patlovich1,Robert J.Emery1(1.The University of Texas Health Science Center at Houston,Environmental Health&Safety,6431 Fannin St,CYF G.102,Houston,TX,77030;2.Corresponding author)Abstract:The ability to irradiate cells,tissues,and other biological materials with high-energy photons has been an essential tool in the discovery of numerous biomedical research advancements.展开更多
On the surfaces of celestial bodies with no or thin atmospheres,such as the Moon and Mars,the solar wind irradiation process leads to the formation of hydrogen and helium enriched regions in the extraterrestrial soil ...On the surfaces of celestial bodies with no or thin atmospheres,such as the Moon and Mars,the solar wind irradiation process leads to the formation of hydrogen and helium enriched regions in the extraterrestrial soil particles.However,soil particles on the Earth with the similar composition lack such structures and properties.This discrepancy raises a key question whether there is a direct relationship between solar wind irradiation and the alterations in the structure and chemical performance of extraterrestrial materials.To address this question,this work investigates the effects of proton irradiation,simulating solar wind radiation,on the structure and photothermal catalytic properties of the classic catalyst In_(2)O_(3).It reveals that proton irradiation induces structural features in In_(2)O_(3) analogous to those characteristics of solar wind weathering observed in extraterrestrial materials.Furthermore,after proton beam irradiation with an energy of 30 keV and a dose of 3×10^(17) protons·cm^(-2),the methanol production yield of the In_(2)O_(3) catalyst increased to 2.6 times of its preirradiation level,and the methanol selectivity improved to 2.1 times of the original value.This work provides both theoretical and experimental support for the development of high-efficiency,radiation-resistant photothermal catalysts.展开更多
To know about the radiation effects on the super large array 9 k×9 k CCDs used in a space telescope induced by energetic protons,the experiments of the super large array 9 k×9 k charge coupled devices(CCDs)u...To know about the radiation effects on the super large array 9 k×9 k CCDs used in a space telescope induced by energetic protons,the experiments of the super large array 9 k×9 k charge coupled devices(CCDs)used in the space telescope irradiated by 60 MeV and 100 MeV protons are presented.The samples were exposed by 60 MeV and 100 MeV protons at fluences of 5×10^(9)/cm^(2) and 1×10^(10)/cm^(2),respectively.The degradations of the main performance parameters of the super large array CCDs which are paid special attention to the space telescope are investigated.The full well capacity,mean dark current,and the charge transfer inefficiency(CTI)versus proton fluence are presented,which are tested at very low temperature of-85℃.The annealing tests of 168 h were carried out after proton irradiation.The dark images before and after proton irradiation are also presented to compare the image degradation.The degradation mechanisms of the super large array CCDs irradiated by protons are analyzed.The experimental results show that the main performance parameters of the CCDs are degraded after 60 MeV and 100 MeV protons and the degradations induced by 60 MeV protons are larger than that induced by 100 MeV protons.The experimental results of the super large array CCDs irradiated by protons will provide the basic test data support for orbit life assessment of the space telescope.展开更多
High-entropy alloys(HEAs)exhibit the excellent elevated-temperature performance and irradiation resistance due to the important core effect of serious lattice distortion for impeding dislocation motion,as candidate ma...High-entropy alloys(HEAs)exhibit the excellent elevated-temperature performance and irradiation resistance due to the important core effect of serious lattice distortion for impeding dislocation motion,as candidate materials for nuclear applications.Despite the growth of the nuclear power sector,the effects of high-temperature and high-dose irradiation-induced voids on the mechanical properties of HEA in higher power nuclear reactors remain insufficiently researched,hindering its industrial application.In this study,we establish a consistent parameterization crystal plastic constitutive model for the hardening and creep behaviors of HEA,incorporating the spatial distribution of void size and shape effects,in contrast to traditional creep models that rely on temperature-related fitting parameters of the phenomenological power law equation.The model matches well with experimental data at different temperatures and irradiation doses,demonstrating its robustness.The effects of irradiation dose,temperature,and degree of lattice distortion on irradiation hardening and creep behavior of void-containing HEA are investigated.The results indicate that HEA with high lattice distortion exhibits better creep resistance under higher stress loads.The yield stress of irradiated HEA increases with increasing irradiation dose and temperature.The creep resistance increases with increasing irradiation dose and decreases with increasing irradiation temperature.The increase in irradiation dose causes a specific morphological transformation from spherical to cubic voids.The modeling and results could provide an effective theoretical way for tuning the yield strength and alloy design in advanced HEAs to meet irradiation properties.展开更多
Additively manufactured stainless steel exhibits different oxidation and corrosion properties compared with traditional counterparts.Molecular dynamics simulations were performed to systematically investigate Cr diffu...Additively manufactured stainless steel exhibits different oxidation and corrosion properties compared with traditional counterparts.Molecular dynamics simulations were performed to systematically investigate Cr diffusion near nanopores,in order to elucidate the fast formation of dense oxidation layers in laser powder bed fusion processed 304L stainless steel after ion irradiation.The influence of pore diameter and temperature on Cr diffusion was studied in Fe simulation boxes with 1 at.%Cr and random nanometric pores.The results show that the existence of nanopores significantly accelerates Cr diffusion,facilitating the formation of oxide layers.While increasing with temperature,the diffusion coefficient does not increase uniformly with pore diameter.Regarding the nanopores with diameters of 4.82-13.25Å,the diffusion coefficient of Cr in their vicinity is maximized at diameter of about 6Å.The specific fast diffusion paths near the nanopores were exposed and discussed.展开更多
Controllable rock cracking technology is crucial for the exploration and exploitation of deep underground resources.Many existing studies have been dedicated to the laser-assisted rock-weakening technology.It has been...Controllable rock cracking technology is crucial for the exploration and exploitation of deep underground resources.Many existing studies have been dedicated to the laser-assisted rock-weakening technology.It has been proved that laser irradiation can improve drilling and blasting efficiency when combined with mechanical rock fracturing methods,which are irrelevant for borehole stabilization.To improve the latter,this study used laser ablation for borehole reinforcement.The high-power laser was applied to typical rock samples(sandstone,mudstone and coal)in both dry and saturated conditions.Multi-technique observations and measurements were used to fully understand the peculiar modifications of the specimens under laser treatment,i.e.mechanical loading,acoustic emission(AE)monitoring,digital image correlation(DIC)strain field evaluation,infrared thermography(IRT)monitoring and X-ray computed tomography(CT)scanning.The results showed that,in addition to the effects already demonstrated,laser irradiation can improve the strength of the soft rock,especially in the saturated state.The process involved a complicated phase change including melting and evaporation of the matrix under high-temperature and high-pressure to form a glassy high strength silicate material.This process is similar to the reaction between molten lava and water,or the impact of an asteroid on the earth.Inspired by the results,a conceptual path for a new borehole stabilization technology using laser ablation was outlined.展开更多
文摘To investigate the DNA polymorphism of M2 plants of Lotus japonicus induced by heavy ion beam, dry seeds were irradiated by carbon ion beams accelerated by Heavy Ion Research Facility in Lanzhou (HIRFL). Inter simple sequence repeat (ISSR) assay were utilized to explore the DNA variation of M2 plants irradiated by 400 Gy carbon ion beams. ISSR technique is an effective molecular marker method based on polymerase chain reaction amplification of template DNA by a single primer with 1626 bp[1]. ISSR can detect the differences of genetic structure of various life materials rapidly.
文摘Arabidopsis thaliana is one of the most commonly used model plants due to its short life cycle and concise genome.As a novel physical mutagen, heavy ion beams have been widely used in plant breeding. The most significant advantages of heavy ion beams are the higher linear energy transfer (LET) and relative biological effectiveness (RBE), inducing a broad spectrum of mutation phenotypes even at low irradiation[1]. In order to investigate the effects on DNA behavior of Arabidopsis thaliana mutants induced by carbon ion irradiations, inter-simple sequence repeat (ISSR), a DNA-based molecular marker technique, was performed to assess the genetic polymorphism.
基金Project supported by the National Natural Science Foundation of China(Grant No.61176090)the National Science and Technology Project 02,China(Grant No.2013ZX02303-004)
文摘In this paper, two microwave irradiation methods：（i） liquid-phase microwave irradiation（MWI） reduction of graphite oxide suspension dissolved in de-ionized water and N, N-dimethylformamide, respectively, and（ii） solid-phase MWI reduction of graphite oxide powder have been successfully carried out to reduce graphite oxide. The reduced graphene oxide products are thoroughly characterized by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectral analysis, Raman spectroscopy, UV-Vis absorption spectral analysis,and four-point probe conductivity measurements. The results show that both methods can efficiently remove the oxygencontaining functional groups attached to the graphite layers, though the solid-phase MWI reduction method can obtain far more efficiently a higher quality-reduced graphene oxide with fewer defects. The I（D）/I（G） ratio of the solid-phase MWI sample is as low as 0.46, which is only half of that of the liquid-phase MWI samples. The electrical conductivity of the reduced graphene oxide by the solid method reaches 747.9 S/m, which is about 25 times higher than that made by the liquid-phase method.
文摘Swift heavy ions in matter lose energy mainly through electronic processes.Since the energy deposition is centered in a very small region with a very high energy density,new effects such as production of alkyne end group can be induced.In this work,PET,PS,PC and PI films are irradiated with Ar,Kr,Xe and U ions and the relationship of the alkyne end group production with electronic energy loss is studied by Fourier transformed infrared infrared(FTLR)spectra measurements.
文摘In our previous work~[1],we have studied photoluminescence(PL)from 5.0×10^(17) C-ions/cm^2 doped SiO_2 films after 335 and 855 MeV^(40)Ar or 1.98 GeV^(84)Kr ion irradiations.It was found that PL bands centred at～430nm and～380 nm were formed in the C-doped SiO_2 films and the PL intensity decreases with electronic energy loss S_e increasing.In the present work,we studied the PL properties of C-doped SiO_2 films after 1.75 GeV Xe and 2.71 GeV U ion irradiations.
文摘Ion irradiation of polymers can induce irreversible changes in their macroscopic propcrties.Electronic excitation,ionization,chains scission and cross-links as well as mass losses are acccpted as the fundamental events that givc rise to the observed macroscopic changes.In this work PET films were irradiated with high-
文摘Background: The skin serves as the first line of defense for the human body. Direct sunlight contains damaging radiations that can speed up the ageing process of the skin, resulting in wrinkles, leathery skin, dark patches, and solar elastosis. Objectives: To evaluate the effect of multiple solar irradiation related factors at the protein level in human dermal fibroblast (HDF). The overall effect of individual solar irradiations such as Infrared A (IRA), blue light (BL), UVA, and UVB on HDF cells and the extent of molecular level aberrations to be assessed and compared against each. Methods: Label-free quantitative proteomics (MS/MS) approach has been adopted in this study to observe the protein level changes induced in the HDF cells through various exposures of full light sources. Following that, downstream insilico analysis has been carried out. Results: In this study, it is demonstrated all the four different solar irradiations significantly contribute to the molecular degeneration of skin cells through various mechanisms. This study confirms that BL down-regulates DNA repair proteins and the skin cells-HDF stimulate the histone proteins as a response mechanism to maintain the chromosomal integrity. Conclusions: The proteomics experiment carried out in the current study intends to support the future sun care products based on full light protection technology that can be custom designed to provide complete protection from the solar radiation. Similar technology could enhance the further investigations for deeper understanding of induction, mode of action, and prevention of skin damage from extensive solar irradiation.
文摘We studied the oxygen etching of individual single-walled carbon nanotubes on silicon oxide substrates using atomic force microscopy and high-temperature environmental scanning electron microscopy. Our in situ observations show that carbon nanotubes are not progressively etched from their ends, as frequently assumed, but disappear segment by segment. Atomic force microscopy, before and after oxidation, reveals that the oxidation of carbon nanotubes on substrates proceeds through a local cutting that is followed by a rapid etching of the disconnected nanotube segment. Unexpectedly, semiconducting nanotubes appear more reactive under these conditions than metallic ones. We also show that exposure to electron and laser beams locally increases the chemical reactivity of carbon nanotubes on such substrates. These results are rationalized by considering the effect of substrate-trapped charges on the nanotube density of states close to the Fermi level, which is impacted by the substrate type and the exposure to electron and laser beams.
基金supported by the IITP(Institute for Information&Communications Technology Planning&Evaluation)under the ITRC(Information Technology Research Center)support program(IITP-2025-RS-2024-00438288)grant funded by the Korea government(MSIT)+1 种基金National Research Council of Science&Technology(NST)grant by the MSIT(Aerospace Semiconductor Strategy Research Project No.GTL25051-000)supported by the IC Design Education Center(IDEC),Korea。
文摘This work presents a systematic analysis of proton-induced total ionizing dose(TID)effects in 1.2 k V silicon carbide(SiC)power devices with various edge termination structures.Three edge terminations including ring-assisted junction termination extension(RA-JTE),multiple floating zone JTE(MFZ-JTE),and field limiting rings(FLR)were fabricated and irradiated with45 Me V protons at fluences ranging from 1×10^(12) to 1×10^(14) cm^(-2).Experimental results,supported by TCAD simulations,show that the RA-JTE structure maintained stable breakdown performance with less than 1%variation due to its effective electric field redistribution by multiple P+rings.In contrast,MFZ-JTE and FLR exhibit breakdown voltage shifts of 6.1%and 15.2%,respectively,under the highest fluence.These results demonstrate the superior radiation tolerance of the RA-JTE structure under TID conditions and provide practical design guidance for radiation-hardened Si C power devices in space and other highradiation environments.
基金supported by the National Natural Science Foundation of China(No.12305385)Key Projects of Scientific Research of the Hunan Provincial Department of Education(22A0310)the Research Startup Project of University of South China(220XQD025).
文摘In this study,the dosimetric characteristics(thickness applicability,preheating time,temperature and humidity dependence,in-batch uniformity,readout reproducibility,dose linearity,self-decay,and electron energy response)of engineered polycarbonate films irradiated with an electron beam(0–600 kGy)were investigated using photoluminescence spectroscopy.The results show a linear relationship between photoluminescence intensity and radiation dose when the thickness of the polycarbonate film is 0.3 mm.A higher fluorescence intensity can be obtained by preheating at 60℃ for 180 min before photoluminescence spectrum analysis.As the temperature during spectral testing and the ambient humidity(during and after irradiation)increased,the photoluminescence intensity of the polycarbonate films decreased.The photoluminescence intensity deviation of the polycarbonate films produced within the same batch at 100 kGy is 2.73%.After ten times of repeated excitations and readouts,the coefficients of variation in photoluminescence intensity are less than 8.6%,and the linear correlation coefficient between photoluminescence intensity and irradiation dose is 0.965 in the dose capture range of 20–600 kGy.Within 60 days of irradiation,the photoluminescence intensity of the polycarbonate film decreased to 60%of the initial value.The response of the 0.3 mm polycarbonate films to electron beams with energies exceeding 3.5 MeV does not differ significantly.This comprehensive analysis indicates the potential of polycarbonate films as a high-radiation dose detection material.
文摘The most amazing chemistry is the light-driven water splitting reaction occurred in the oxygen-evolving complex of phototsystem II in higher plants, green algae, and cyanobacteria. Mn, in the form of Mn4CaOs cluster in photosystem II, is responsible for the catalytic water splitting reaction as well as plays roles in photosystem II dynamics to irradiation and temperatures. Manganese hypothesis of UV-initiated photoinhibition as a direct target is established, and thermal inactivation of photosystem II involves the valence and structural changes of manganese. Recent progresses in understanding the roles of manganese in photoinhibition especially under UV light and in thermal inactivation including elevated temperatures using synthetic models and native PS II complexes are summarized and evaluated. Potential problems and possible solutions are discussed and presented.
基金Supported by NSFC (10475102)Scientific Research Foundation of Heze University,China (XY09WL02)Heze University Doctoral Foundation (XY10BS02)
文摘Thermally grown amorphous SiO2 films were implanted at room temperature with 100 keV C-ions to 5.0× 10^17 or 1.2× 10^18 ions/cm2. These samples were irradiated at room temperature with 853 MeV Pb-ions to 5.0× 10^11, 1.0× 10^12, 5.0× 10^12 ions/cm2, or with 308 MeV Xe-ions to 1.0× 10^12, 1.0× 10^13, 1.0× 10^14 ions/cm2, respectively. Then the samples were investigated using micro-Raman spectroscopy. Prom the obtained Raman spectra, we deduced that Si-C bonds and sp2 carbon sites were created and nano-inclusions may also be produced in the heavy ion irradiated C-doped SiO2. Furthermore, some results show that Pb ion irradiations could produce larger size inclusions than Xe ions and the fluence. The possible modification process of C-doped discussed. inclusion size decreased with increasing the irradiation a-SiO2 under swift heavy ion irradiations was briefly
基金supported by the Science and Technology Planning Project of Fujian Province(No.2023Y4015)the Marine and Fishery Development Special Fund of Xiamen(No.23YYST064QCB36)the Natural Science Foundation of Fujian Province(No.2021J011210).
文摘The removal of ammonia nitrogen(NH_(4)^(+)-N)and bacteria from aquaculture wastewater holds paramount ecological and production significance.In this study,Pt/RuO_(2)/g-C_(3)N_(4)photocatalysts were prepared by depositing Pt and RuO_(2)particles onto g-C_(3)N_(4).The physicochemical properties of photocatalysts were explored by X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),X-ray diffraction(XRD),and UV–vis diffuse reflectance spectrometer(UV–vis DRS).The photocatalysts were then applied to the removal of both NH_(4)^(+)-N and bacteria from simulated mariculture wastewater.The results clarified that the removals of both NH_(4)^(+)-N and bacteria were in the sequence of g-C_(3)N_(4)<RuO_(2)/g-C_(3)N_(4)<Pt/g-C_(3)N_(4)<Pt/RuO_(2)/g-C_(3)N_(4).This magnificent photocatalytic ability of Pt/RuO_(2)/g-C_(3)N_(4)can be interpreted by the transfer of holes from g-C_(3)N_(4)to RuO_(2)to facilitate the in situ generation of HClO from Cl^(−)in wastewater,while Pt extracts photogenerated electrons for H_(2)formation to enhance the reaction.The removal of NH_(4)^(+)-N and disinfection effect were more pronounced in simulated seawater than in purewater.The removal efficiency ofNH_(4)^(+)-N increases with an increase in pH of wastewater,while the bactericidal effect was more significant under a lower pH in a pH range of 6–9.In actual seawater aquaculture wastewater,Pt/RuO_(2)/g-C_(3)N_(4)still exhibits effective removal efficiency of NH_(4)^(+)-N and bactericidal performance under sunlight.This study provides an alternative avenue for removement of NH_(4)^(+)-N and bacteria from saline waters under sunlight.
基金the National Natural Science Foun-dation of China(Nos.U2241235,U2167213 and U2067218)the Project funded by the Science&Technology Department of Sichuan Province(No.21MZGC0400,No.2022JDJQ0021)+3 种基金the China National Nuclear Corporation(CNNC)Science Fund for Talented Young Scholars(No.CNNC-2021-31)the Funds of Science and Technol-ogy on Reactor Fuel and Materials Laboratory(No.6142A06190510)the fund from the Fundamental Research Funds for the Cen-tral Universities(No.N2202020)XingLiao Talent Plan(No.XLYC2203202).
文摘The Mg alloys with combination of high strength and excellent irradiation resistance are currently re-quired for research reactors.In this work,the novel Mg-3Mn-0.5Ca alloy with a high strength of over 300 MPa has been fabricated via co-addition of Mn and Ca elements.Moreover,the Xe ion implantation(300℃/4.5×10^(15)ions/cm^(2))is conducted for pure Mg,Mg-3Mn and Mg-3Mn-0.5Ca alloys.Microstruc-ture characterization shows that the number density of dislocation loops is comparable between Mg-3Mn and pure Mg,while the phase boundary of nano-Mn particles could act as the sink to absorb more Xe atoms,resulting in the abundant formation of Xe bubbles in the matrix of irradiated Mg-3Mn alloy.With further minor addition of Ca element,the formation of Xe bubbles and dislocation loops in Mg-3Mn-0.5Ca alloy has been obviously suppressed,and the abundant grain boundaries(GBs)due to grain refinement then act as the sink region for Xe precipitation.The limited number density of Xe bubbles leads to the extremely low swelling ratio in Mg-3Mn-0.5Ca alloy,∼0.08%.The result above suggests that the Mn and Ca co-addition could enhance the mechanical properties and irradiation tolerance of Mg alloys,si-multaneously.The present low-alloying strategy would provide a new design reference for novel nuclear materials.
文摘Establishing Consensus with Users of Research Irradiator Devices to Facilitate Source Type Replacement Danette R.Fennesy1,Janet M.Gutiérrez1,2,Scott J.Patlovich1,Robert J.Emery1(1.The University of Texas Health Science Center at Houston,Environmental Health&Safety,6431 Fannin St,CYF G.102,Houston,TX,77030;2.Corresponding author)Abstract:The ability to irradiate cells,tissues,and other biological materials with high-energy photons has been an essential tool in the discovery of numerous biomedical research advancements.
基金National Key Research and Development Program of China(2020YFA0710302)The Major Research Plan of the National Natural Science Foundation of China(91963206)+2 种基金The National Natural Science Foundation of China(52072169,51972164,51972167,22279053)The Fundamental Research Funds for the Central Universities(14380193)The Program for Guangdong Introducing Innovative and Entrepreneurial Teams(2019ZT08L101).
文摘On the surfaces of celestial bodies with no or thin atmospheres,such as the Moon and Mars,the solar wind irradiation process leads to the formation of hydrogen and helium enriched regions in the extraterrestrial soil particles.However,soil particles on the Earth with the similar composition lack such structures and properties.This discrepancy raises a key question whether there is a direct relationship between solar wind irradiation and the alterations in the structure and chemical performance of extraterrestrial materials.To address this question,this work investigates the effects of proton irradiation,simulating solar wind radiation,on the structure and photothermal catalytic properties of the classic catalyst In_(2)O_(3).It reveals that proton irradiation induces structural features in In_(2)O_(3) analogous to those characteristics of solar wind weathering observed in extraterrestrial materials.Furthermore,after proton beam irradiation with an energy of 30 keV and a dose of 3×10^(17) protons·cm^(-2),the methanol production yield of the In_(2)O_(3) catalyst increased to 2.6 times of its preirradiation level,and the methanol selectivity improved to 2.1 times of the original value.This work provides both theoretical and experimental support for the development of high-efficiency,radiation-resistant photothermal catalysts.
基金The National Science Foundation of China(U2167208,11875223)Natural Science Basic Research Program of Shaanxi(2024JC-JCQN)The Foundation of State Key Laboratory of China(NKLIPR2320)。
文摘To know about the radiation effects on the super large array 9 k×9 k CCDs used in a space telescope induced by energetic protons,the experiments of the super large array 9 k×9 k charge coupled devices(CCDs)used in the space telescope irradiated by 60 MeV and 100 MeV protons are presented.The samples were exposed by 60 MeV and 100 MeV protons at fluences of 5×10^(9)/cm^(2) and 1×10^(10)/cm^(2),respectively.The degradations of the main performance parameters of the super large array CCDs which are paid special attention to the space telescope are investigated.The full well capacity,mean dark current,and the charge transfer inefficiency(CTI)versus proton fluence are presented,which are tested at very low temperature of-85℃.The annealing tests of 168 h were carried out after proton irradiation.The dark images before and after proton irradiation are also presented to compare the image degradation.The degradation mechanisms of the super large array CCDs irradiated by protons are analyzed.The experimental results show that the main performance parameters of the CCDs are degraded after 60 MeV and 100 MeV protons and the degradations induced by 60 MeV protons are larger than that induced by 100 MeV protons.The experimental results of the super large array CCDs irradiated by protons will provide the basic test data support for orbit life assessment of the space telescope.
基金support from the National Natural Science Foundation of China(Nos.12302083,U2267252,12372069,and 12172123)the China Postdoctoral Science Foundation(Nos.2023M731061 and BX20230109)+1 种基金the Natural Science Foundation of Hunan Province(No.2022JJ20001)the Hunan Provincial Innovation Foundation for Postgraduate(No.CX20230420).
文摘High-entropy alloys(HEAs)exhibit the excellent elevated-temperature performance and irradiation resistance due to the important core effect of serious lattice distortion for impeding dislocation motion,as candidate materials for nuclear applications.Despite the growth of the nuclear power sector,the effects of high-temperature and high-dose irradiation-induced voids on the mechanical properties of HEA in higher power nuclear reactors remain insufficiently researched,hindering its industrial application.In this study,we establish a consistent parameterization crystal plastic constitutive model for the hardening and creep behaviors of HEA,incorporating the spatial distribution of void size and shape effects,in contrast to traditional creep models that rely on temperature-related fitting parameters of the phenomenological power law equation.The model matches well with experimental data at different temperatures and irradiation doses,demonstrating its robustness.The effects of irradiation dose,temperature,and degree of lattice distortion on irradiation hardening and creep behavior of void-containing HEA are investigated.The results indicate that HEA with high lattice distortion exhibits better creep resistance under higher stress loads.The yield stress of irradiated HEA increases with increasing irradiation dose and temperature.The creep resistance increases with increasing irradiation dose and decreases with increasing irradiation temperature.The increase in irradiation dose causes a specific morphological transformation from spherical to cubic voids.The modeling and results could provide an effective theoretical way for tuning the yield strength and alloy design in advanced HEAs to meet irradiation properties.
基金financial support of National Natural Science Foundation of China(Nos.U2241245,52073176 and U22B2067)Natural Science Foundation of Shenyang(No.23-503-6-05)Shanghai Engineering Research Center of High-Performance Medical Device Materials(No.20DZ2255500).
文摘Additively manufactured stainless steel exhibits different oxidation and corrosion properties compared with traditional counterparts.Molecular dynamics simulations were performed to systematically investigate Cr diffusion near nanopores,in order to elucidate the fast formation of dense oxidation layers in laser powder bed fusion processed 304L stainless steel after ion irradiation.The influence of pore diameter and temperature on Cr diffusion was studied in Fe simulation boxes with 1 at.%Cr and random nanometric pores.The results show that the existence of nanopores significantly accelerates Cr diffusion,facilitating the formation of oxide layers.While increasing with temperature,the diffusion coefficient does not increase uniformly with pore diameter.Regarding the nanopores with diameters of 4.82-13.25Å,the diffusion coefficient of Cr in their vicinity is maximized at diameter of about 6Å.The specific fast diffusion paths near the nanopores were exposed and discussed.
基金supported by the National Natural Science Foundation of China(Grant No.51804296)China Scholarship Council Grant(Grant No.CSC#202006425019).
文摘Controllable rock cracking technology is crucial for the exploration and exploitation of deep underground resources.Many existing studies have been dedicated to the laser-assisted rock-weakening technology.It has been proved that laser irradiation can improve drilling and blasting efficiency when combined with mechanical rock fracturing methods,which are irrelevant for borehole stabilization.To improve the latter,this study used laser ablation for borehole reinforcement.The high-power laser was applied to typical rock samples(sandstone,mudstone and coal)in both dry and saturated conditions.Multi-technique observations and measurements were used to fully understand the peculiar modifications of the specimens under laser treatment,i.e.mechanical loading,acoustic emission(AE)monitoring,digital image correlation(DIC)strain field evaluation,infrared thermography(IRT)monitoring and X-ray computed tomography(CT)scanning.The results showed that,in addition to the effects already demonstrated,laser irradiation can improve the strength of the soft rock,especially in the saturated state.The process involved a complicated phase change including melting and evaporation of the matrix under high-temperature and high-pressure to form a glassy high strength silicate material.This process is similar to the reaction between molten lava and water,or the impact of an asteroid on the earth.Inspired by the results,a conceptual path for a new borehole stabilization technology using laser ablation was outlined.
