In this paper, various strategies of spiral irradiating scheme for the flame forming of a bowl shaped surface are investigated experimentally and numerically. Experimental work is performed using a flame torch integra...In this paper, various strategies of spiral irradiating scheme for the flame forming of a bowl shaped surface are investigated experimentally and numerically. Experimental work is performed using a flame torch integrated with a 2-axis CNC workstation. The ABAQUS implicit solver is used in the numerical simulation. Three different strategies of the spiral irradiating scheme are investigated for the flame forming of a bowl shaped surface. The first strategy is the Simple spi- ral irradiating scheme, the second is the Rotational spiral irradiating scheme, and the third is the Symmetrical-Rotational spiral irradiating scheme. The results show that using the Symmetrical- Rotational spiral irradiating scheme, a bowl shaped surface with the maximum deformation can be produced, followed by using the Rotational scheme, and the Simple spiral scheme. It is also concluded from the results that the spiral irradiating scheme with Symmetrical-Rotational, Rota- tional and Simple spiral schemes lead to the maximum symmetries in the produced bowl shaped surface, respectively. All the numerical results are in good agreement with the experimental ob- servations.展开更多
Therapeutic effect of bronchisl asthma treated With CO<sub>2</sub> laser irradiating points was ob-served.Ninety-six cases of bronchial asthma,that were considered cold and insufficiency type accord-ing to...Therapeutic effect of bronchisl asthma treated With CO<sub>2</sub> laser irradiating points was ob-served.Ninety-six cases of bronchial asthma,that were considered cold and insufficiency type accord-ing to TCM,were divided into two groups:one treated with CO<sub>2</sub> laser irradiation at Tiantu（CV 22）,Danzhong（CV 17）,Feishu（BL13）and Dingchuan（EX-BI）（n=48）,and the other with warmmoxibustion at same points（n=48）.The symptoms,physical signs and pulmonary ventilation（PEF.VC,FEV<sub>1</sub>.0,FEV1％and MMEF）were taken as parameter.xhe results showed that thetherapeutic effect In laser irradiation group was better than that in moxibustion group.Moreover,laser irradiation could obviously improve pulmonary ventilation in patients.Therefore,CO<sub>2</sub> laser irra-diation is an effective therapy for bronchial asthma.展开更多
The design of 10MeV/20kW high power irradiating accelerator is presented.The Backward-Traveling-Wave (BTW)accelerating structure is adopted.This structure combines the advantage of traveling-wave accelerator structure...The design of 10MeV/20kW high power irradiating accelerator is presented.The Backward-Traveling-Wave (BTW)accelerating structure is adopted.This structure combines the advantage of traveling-wave accelerator structure with low power reflection and high stability and standing-wave accelerator structure with high shunt impedance.The work frequency of this accelerator is 2856MHz.Designed by Code AccDesign which is coded by ourselves,the output electron beam with final energy 10MeV and peak current 300mA was reached.The length of the accelerating tube is 1.5m,and the power efficiency from microwave to electron beam is 66%.The temperature and stress distribution were simulated.And the frequency shift by microwave loss was calculated.展开更多
A Novel Dosimetry Method for Small Animal Irradiators Using 3D-printed Mouse Phantoms and Alanine Dosimeters.Christopher Duncan1,Chad Gunther1(1.C&C Irradiator Service,LLC,Washington,DC,20006.)Abstract:Accurate do...A Novel Dosimetry Method for Small Animal Irradiators Using 3D-printed Mouse Phantoms and Alanine Dosimeters.Christopher Duncan1,Chad Gunther1(1.C&C Irradiator Service,LLC,Washington,DC,20006.)Abstract:Accurate dosimetry is a crucial component of small animal and preclinical irradiation studies.展开更多
Single-crystal GaN epilayers were irradiated with heavy inert gas ions(2.3-MeV Ne^(8+),5.3-MeV Kr^(19+))to fluences ranging from 1.0×1.0^(11) to 1.0×1.0^(15)ions∕cm^(2).The strain-related damage accumulatio...Single-crystal GaN epilayers were irradiated with heavy inert gas ions(2.3-MeV Ne^(8+),5.3-MeV Kr^(19+))to fluences ranging from 1.0×1.0^(11) to 1.0×1.0^(15)ions∕cm^(2).The strain-related damage accumulation versus ion fluences was studied using highresolution X-ray diffraction(HRXRD)and ultraviolet–visible(UV–Vis)spectroscopy.The results showed that the damage accumulation was mainly dominated by nuclear energy loss.When the ion fluence was less than∼0.055 displacement per atom(dpa),the lattice expansions and lattice strains markedly increased linearly with increasing ion fluences,accompanied by a slow enhancement in the dislocation densities,distortion parameters,and Urbach energy for both ion irradiations.Above this fluence(∼0.055 dpa),the lattice strains presented a slight increase,whereas a remarkable increase was observed in the dislocation densities,distortion parameters,and Urbach energy with the ion fluences after both ion irradiations.∼0.055 dpa is the threshold ion fluence for defect evolution and lattice damage related to strain.The mechanisms underlying the damage accumulation are discussed in detail.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
From an engineering feasibility standpoint, what level of performance metrics can be ultimately achieved when designing a reactor using well-established nuclear fuels and structural materials that have already undergo...From an engineering feasibility standpoint, what level of performance metrics can be ultimately achieved when designing a reactor using well-established nuclear fuels and structural materials that have already undergone irradiation testing? The irradiation capability, which hinges on parameters like neutron flux level, irradiation channels' volume, and fuel cycle duration, is a core indicator for high-flux reactors. We propose a conceptual design of an ultra-high flux fast reactor(UFFR) with strong irradiation capability, which utilizes U-20Pu-10Zr alloy fuel and employs lead-bismuth as the coolant. The maximum neutron flux in the core reaches 1.32×10^(16) cm^(-2)s^(-1), while the average neutron flux in the irradiation channels attains 1.19×10^(16) cm^(-2)s^(-1). The volume of the central irradiation channel exceeds 10000 cm^(3), and the fuel cycle duration is 165 d, placing all its performance indicators among the top in the world. Based on the analyses of reactor physics and thermalhydraulics, it has been demonstrated that all reactivity coefficients are negative and all physical parameters meet the design criteria, ensuring the inherent safety of UFFR. An assessment of the irradiation capability has been carried out based on californium-252(^(252)Cf) production, indicating that the irradiation capability of UFFR surpasses that of the high flux isotope reactor(HFIR). The yield of ^(252)Cf from UFFR is 14.39 times that of HFIR, and its nuclei conversion rate is 3.21 times that of HFIR.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
To address the poor mechanical performance and improve the tribological properties of self-lubricating polyphenylene sulfide/irradiation treated polytetrafluoroethylene(PPS/i-PTFE)blends,different aspect ratio carbon ...To address the poor mechanical performance and improve the tribological properties of self-lubricating polyphenylene sulfide/irradiation treated polytetrafluoroethylene(PPS/i-PTFE)blends,different aspect ratio carbon fibers(i.e.,PSCF:50,SCF:about 429)were introduced as reinforcement fillers.The results showed that the hybriding of PSCF and SCF at certain mass ratios exhibited simultaneous enhancement of mechanical and tribological performance for PPS/i-PTFE blend through the construction of synergistic lubrication and mechanical interlocking network.Specifically,the flexural strength and modulus of PPS/i-PTFE were increased by 125.6% and 389.3%,the friction coefficient and specific wear rate were decreased by 13.9% and 95%,respectively.It was worth noting that PPS composites possessed excellent integrated performance which were able to withstand sliding action under high PV(≥10 MPa·m/s)conditions,as assessed by a customized pin-on-disc tester.This work demonstrated that the formation of intact lubricating film combined with the enhanced thermal and mechanical properties were favorable for improving the tribological properties of PPS-based composites,which makes them suitable for advanced engineering applications.展开更多
Conventional polyethylene(PE)fibers face limitations in large-scale industrial applications due to their poor thermal stability and inherent hydrophobicity,which restrict processing temperatures and dyeability,especia...Conventional polyethylene(PE)fibers face limitations in large-scale industrial applications due to their poor thermal stability and inherent hydrophobicity,which restrict processing temperatures and dyeability,especially in blended fabric production.In this research,a one-step ultraviolet(UV)irradiation technology was employed to modify medium molecular weight PE fibers through simultaneous crosslinking and grafting modifications,aiming to enhance their thermal stability and hydrophilicity.The modification employed a cost-effective,UV-initiated crosslinking system consisting of benzophenone(BP)as the photoinitiator and triallyl isocyanurate(TAIC)as the cocrosslinker.Acrylic acid(AA)was selected as the grafting monomer.These modifiers were thoroughly mixed with the PE matrix in a liquid-phase environment,and the mixture was melt-spun into fibers.The resulting fibers were then subjected to UV irradiation,which triggered the crosslinking and grafting reactions.The effects of the mass fraction of each component and irradiation parameters on modification efficacy were systematically investigated,followed by a comprehensive characterization of the modified PE fibers.The modified PE fibers achieved optimal thermal stability under the following conditions:2.0%mass fractions for both BP and TAIC,a UV irradiation intensity of 2000 mW/cm^(2),and an equivalent irradiation time of 60 s.This synergistic modification approach enables the fibers to maintain superior morphological integrity and mechanical performance when exposed to elevated temperatures ranging from 130 to 150℃.Meanwhile,an AA grafting mass fraction of 2.0%maximizes hydrophilicity with minimal impact on other properties,as evidenced by a dramatic reduction in the water contact angle(WCA)from 105.0°(hydrophobic)to 48.4°(hydrophilic).These improvements confirm the effectiveness of the modification strategy in synergistically enhancing both thermal stability and hydrophilicity of PE fibers.展开更多
The failure mechanisms and structural damage of SiC MOSFETs induced by heavy ion irradiation were demonstrated.The findings reveal three degradation modes,depending on the drain voltage.At a relatively low voltage,the...The failure mechanisms and structural damage of SiC MOSFETs induced by heavy ion irradiation were demonstrated.The findings reveal three degradation modes,depending on the drain voltage.At a relatively low voltage,the damage is triggered by the formation and activation of gate latent damage(LDs),with damage concentrated in the gate oxide.The second degradation mode involves permanent leakage current degradation,with damage progressively transitioning from the oxide to the SiC material as the drain voltage escalates.Ultimately,the device undergoes catastrophic burnout above certain voltages,characterized by the lattice temperature reaching the sublimation point of SiC,resulting in surface cavity and complete structural destruction.This paper presents a comprehensive investigation of SiC MOSFETs under heavy ion exposure,providing radiation resistance methods of SiC-based devices for aerospace applications.展开更多
Haynaldia villosa Schur.(syn.Dasypyrum villosum Candargy,2n=14,VV)has been proved to be an important genetic resource for wheat improvement.The development of translocation with small alien chromosome segments,especia...Haynaldia villosa Schur.(syn.Dasypyrum villosum Candargy,2n=14,VV)has been proved to be an important genetic resource for wheat improvement.The development of translocation with small alien chromosome segments,especially interstitial translocation,will be helpful for better utilization of its useful genes.Up to now,most of the reported Triticum aestivum–H.villosa translocation lines are involved in a whole arm or large alien fragments.In this paper,we report a highly efficient approach for the creation of small chromosome segment translocation lines.Before flowering,the female gametes of wheat-H.villosa 6VS/6AL translocation line were irradiated by 60CO-γray at 160 Rad/M dosage rate and three dosages(1600,1920,2240 Rad).Anthers were removed from the irradiated florets on the same day and the florets were pollinated with normal fresh pollens of T.aestivum cv.Chinese Spring after 2-3 days.Genomic in situ hybridization(GISH)at mitosis metaphase of root-tip cell of M1 plants was used to detect the chromosome structural changes involving 6VS of H.villosa.Among the 534 M1 plants screened,97 plants contained small segment chromosome structural changes of 6VS,including 80 interstitial translocation chromosomes,57 terminal translocation chromosomes and 55 deletion chromosomes.For the 2240 Rad dosage treatment,the inducement frequencies of interstitial translo-cation,terminal translocation and deletion were 21.02%,14.01%,and 14.65%,respectively,which were much higher than those previously reported.The M2 seeds were obtained by backcrossing of 74 M1 plants involving 146 chromosomes structural changes of 6VS,and it was found that the structural aberrations in the M1 plants could be transmitted to their progenies.Irradiating mature female gametes of whole arm translocation is a new and highly efficient approach for creation of small segment chromosome struc-tural changes,especially for interstitial translocations.展开更多
Ultrafast electron sources, which enable high spatiotemporal resolution in time-resolved electron microscopy and scanning probe microscopy, are receiving increased attention. The most widely used method for achieving ...Ultrafast electron sources, which enable high spatiotemporal resolution in time-resolved electron microscopy and scanning probe microscopy, are receiving increased attention. The most widely used method for achieving ultrafast electron sources involves irradiating metal tips by ultrashort laser pulses, causing electron beam emission via the photoelectric effect [including photon-driven(quantum) or field-driven(classical) emission]. However, the thermionic electrons emission process due to the heating effect of ultrashort lasers, particularly its dynamic aspects, has rarely been addressed in previous studies. In this paper, we improved the signal-to-noise ratio of a two-pulse correlation measurement on the tip electron emission by nearly two orders of magnitude using a delay time modulation method. This allowed us to obtain information on the temperature evolution of hot electrons and phonons in a non-equilibrium state, and to extract characteristic time scales for electron-phonon and phonon-phonon scattering. Our findings indicate that the thermionic electrons emission, unlike the instantaneous photoelectric effect, causes electron emission to lag behind the laser pulse by tens of picoseconds, thus significantly affecting the detection of ultrafast dynamics of samples. Furthermore, such a lagging effect was found to be sensitive to the local structure of the metal tip, offering new insights into the improved design of ultrafast electron sources.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
Refractory high entropy alloys(RHEAs)have drawn much attention for their potential applications in ad-vanced reactors.While improved irradiation resistance to void swelling and helium bubble formation has been frequen...Refractory high entropy alloys(RHEAs)have drawn much attention for their potential applications in ad-vanced reactors.While improved irradiation resistance to void swelling and helium bubble formation has been frequently reported,experimental investigation regarding their early-stage irradiation damage re-mains insufficient,which hinders the understanding of the behavior of point defects and small clusters.Here we select two typical RHEAs with desired mechanical properties,VTaTi and HfNbZrTi,as well as a conventional V-4Cr-4Ti alloy,and compare their irradiation-induced defect production and hardening under a low-dose irradiation to~0.1 dpa.Significant hardening is observed in V-4Cr-4Ti due to the pin-ning of deformation-induced dislocations by the high density of irradiation-induced loops.In contrast,the hardening in VTaTi is much weaker,corresponding well to the greatly reduced defect density.Strikingly,in HfNbZrTi,visible defect clusters are not observed with a Cs-corrected transmission electron microscope in the whole irradiation range,and no hardening effect is detected.Such strong suppression of irradia-tion damage is attributed to the large lattice distortion based on the ab initio calculations and the local chemical fluctuations based on the atomic-scale elemental mappings,which together hinder the mobility of interstitials.Furthermore,minor irradiation softening is evidenced by cross-sectional nanoindentation tests in HfNbZrTi,which is considered to be related to the evolution of short-range orders and interstitial impurities after irradiation.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
文摘In this paper, various strategies of spiral irradiating scheme for the flame forming of a bowl shaped surface are investigated experimentally and numerically. Experimental work is performed using a flame torch integrated with a 2-axis CNC workstation. The ABAQUS implicit solver is used in the numerical simulation. Three different strategies of the spiral irradiating scheme are investigated for the flame forming of a bowl shaped surface. The first strategy is the Simple spi- ral irradiating scheme, the second is the Rotational spiral irradiating scheme, and the third is the Symmetrical-Rotational spiral irradiating scheme. The results show that using the Symmetrical- Rotational spiral irradiating scheme, a bowl shaped surface with the maximum deformation can be produced, followed by using the Rotational scheme, and the Simple spiral scheme. It is also concluded from the results that the spiral irradiating scheme with Symmetrical-Rotational, Rota- tional and Simple spiral schemes lead to the maximum symmetries in the produced bowl shaped surface, respectively. All the numerical results are in good agreement with the experimental ob- servations.
文摘Therapeutic effect of bronchisl asthma treated With CO<sub>2</sub> laser irradiating points was ob-served.Ninety-six cases of bronchial asthma,that were considered cold and insufficiency type accord-ing to TCM,were divided into two groups:one treated with CO<sub>2</sub> laser irradiation at Tiantu（CV 22）,Danzhong（CV 17）,Feishu（BL13）and Dingchuan（EX-BI）（n=48）,and the other with warmmoxibustion at same points（n=48）.The symptoms,physical signs and pulmonary ventilation（PEF.VC,FEV<sub>1</sub>.0,FEV1％and MMEF）were taken as parameter.xhe results showed that thetherapeutic effect In laser irradiation group was better than that in moxibustion group.Moreover,laser irradiation could obviously improve pulmonary ventilation in patients.Therefore,CO<sub>2</sub> laser irra-diation is an effective therapy for bronchial asthma.
文摘The design of 10MeV/20kW high power irradiating accelerator is presented.The Backward-Traveling-Wave (BTW)accelerating structure is adopted.This structure combines the advantage of traveling-wave accelerator structure with low power reflection and high stability and standing-wave accelerator structure with high shunt impedance.The work frequency of this accelerator is 2856MHz.Designed by Code AccDesign which is coded by ourselves,the output electron beam with final energy 10MeV and peak current 300mA was reached.The length of the accelerating tube is 1.5m,and the power efficiency from microwave to electron beam is 66%.The temperature and stress distribution were simulated.And the frequency shift by microwave loss was calculated.
文摘A Novel Dosimetry Method for Small Animal Irradiators Using 3D-printed Mouse Phantoms and Alanine Dosimeters.Christopher Duncan1,Chad Gunther1(1.C&C Irradiator Service,LLC,Washington,DC,20006.)Abstract:Accurate dosimetry is a crucial component of small animal and preclinical irradiation studies.
基金supported by the Program for National Natural Science Foundation of China(No.11675231)the Sichuan Science and Technology Program(Nos.2022YFG0263 and 2024NSFSC1097)the Scientific Research Starting Foundation for talents(Nos.21zx7109 and 22zx7175,24ycx1005).
文摘Single-crystal GaN epilayers were irradiated with heavy inert gas ions(2.3-MeV Ne^(8+),5.3-MeV Kr^(19+))to fluences ranging from 1.0×1.0^(11) to 1.0×1.0^(15)ions∕cm^(2).The strain-related damage accumulation versus ion fluences was studied using highresolution X-ray diffraction(HRXRD)and ultraviolet–visible(UV–Vis)spectroscopy.The results showed that the damage accumulation was mainly dominated by nuclear energy loss.When the ion fluence was less than∼0.055 displacement per atom(dpa),the lattice expansions and lattice strains markedly increased linearly with increasing ion fluences,accompanied by a slow enhancement in the dislocation densities,distortion parameters,and Urbach energy for both ion irradiations.Above this fluence(∼0.055 dpa),the lattice strains presented a slight increase,whereas a remarkable increase was observed in the dislocation densities,distortion parameters,and Urbach energy with the ion fluences after both ion irradiations.∼0.055 dpa is the threshold ion fluence for defect evolution and lattice damage related to strain.The mechanisms underlying the damage accumulation are discussed in detail.
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 (Grant No.12575180)the Lingchuang Research Project of China National Nuclear Corporation (CNNC)。
文摘From an engineering feasibility standpoint, what level of performance metrics can be ultimately achieved when designing a reactor using well-established nuclear fuels and structural materials that have already undergone irradiation testing? The irradiation capability, which hinges on parameters like neutron flux level, irradiation channels' volume, and fuel cycle duration, is a core indicator for high-flux reactors. We propose a conceptual design of an ultra-high flux fast reactor(UFFR) with strong irradiation capability, which utilizes U-20Pu-10Zr alloy fuel and employs lead-bismuth as the coolant. The maximum neutron flux in the core reaches 1.32×10^(16) cm^(-2)s^(-1), while the average neutron flux in the irradiation channels attains 1.19×10^(16) cm^(-2)s^(-1). The volume of the central irradiation channel exceeds 10000 cm^(3), and the fuel cycle duration is 165 d, placing all its performance indicators among the top in the world. Based on the analyses of reactor physics and thermalhydraulics, it has been demonstrated that all reactivity coefficients are negative and all physical parameters meet the design criteria, ensuring the inherent safety of UFFR. An assessment of the irradiation capability has been carried out based on californium-252(^(252)Cf) production, indicating that the irradiation capability of UFFR surpasses that of the high flux isotope reactor(HFIR). The yield of ^(252)Cf from UFFR is 14.39 times that of HFIR, and its nuclei conversion rate is 3.21 times that of HFIR.
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.
基金financially supported by the National Natural Science Foundation of China(No.52103040)China Postdoctoral Science Foundation(No.2020M673217)the Fundamental Research Funds for the Central Universities(No.2023SCU12022)。
文摘To address the poor mechanical performance and improve the tribological properties of self-lubricating polyphenylene sulfide/irradiation treated polytetrafluoroethylene(PPS/i-PTFE)blends,different aspect ratio carbon fibers(i.e.,PSCF:50,SCF:about 429)were introduced as reinforcement fillers.The results showed that the hybriding of PSCF and SCF at certain mass ratios exhibited simultaneous enhancement of mechanical and tribological performance for PPS/i-PTFE blend through the construction of synergistic lubrication and mechanical interlocking network.Specifically,the flexural strength and modulus of PPS/i-PTFE were increased by 125.6% and 389.3%,the friction coefficient and specific wear rate were decreased by 13.9% and 95%,respectively.It was worth noting that PPS composites possessed excellent integrated performance which were able to withstand sliding action under high PV(≥10 MPa·m/s)conditions,as assessed by a customized pin-on-disc tester.This work demonstrated that the formation of intact lubricating film combined with the enhanced thermal and mechanical properties were favorable for improving the tribological properties of PPS-based composites,which makes them suitable for advanced engineering applications.
文摘Conventional polyethylene(PE)fibers face limitations in large-scale industrial applications due to their poor thermal stability and inherent hydrophobicity,which restrict processing temperatures and dyeability,especially in blended fabric production.In this research,a one-step ultraviolet(UV)irradiation technology was employed to modify medium molecular weight PE fibers through simultaneous crosslinking and grafting modifications,aiming to enhance their thermal stability and hydrophilicity.The modification employed a cost-effective,UV-initiated crosslinking system consisting of benzophenone(BP)as the photoinitiator and triallyl isocyanurate(TAIC)as the cocrosslinker.Acrylic acid(AA)was selected as the grafting monomer.These modifiers were thoroughly mixed with the PE matrix in a liquid-phase environment,and the mixture was melt-spun into fibers.The resulting fibers were then subjected to UV irradiation,which triggered the crosslinking and grafting reactions.The effects of the mass fraction of each component and irradiation parameters on modification efficacy were systematically investigated,followed by a comprehensive characterization of the modified PE fibers.The modified PE fibers achieved optimal thermal stability under the following conditions:2.0%mass fractions for both BP and TAIC,a UV irradiation intensity of 2000 mW/cm^(2),and an equivalent irradiation time of 60 s.This synergistic modification approach enables the fibers to maintain superior morphological integrity and mechanical performance when exposed to elevated temperatures ranging from 130 to 150℃.Meanwhile,an AA grafting mass fraction of 2.0%maximizes hydrophilicity with minimal impact on other properties,as evidenced by a dramatic reduction in the water contact angle(WCA)from 105.0°(hydrophobic)to 48.4°(hydrophilic).These improvements confirm the effectiveness of the modification strategy in synergistically enhancing both thermal stability and hydrophilicity of PE fibers.
基金Project supported by the National Key Research and Development Program of China(Grant No.2023YFA1609000)the National Natural Science Foundation of China(Grant Nos.U2341222,U2441248,12275061,and 12075069)。
文摘The failure mechanisms and structural damage of SiC MOSFETs induced by heavy ion irradiation were demonstrated.The findings reveal three degradation modes,depending on the drain voltage.At a relatively low voltage,the damage is triggered by the formation and activation of gate latent damage(LDs),with damage concentrated in the gate oxide.The second degradation mode involves permanent leakage current degradation,with damage progressively transitioning from the oxide to the SiC material as the drain voltage escalates.Ultimately,the device undergoes catastrophic burnout above certain voltages,characterized by the lattice temperature reaching the sublimation point of SiC,resulting in surface cavity and complete structural destruction.This paper presents a comprehensive investigation of SiC MOSFETs under heavy ion exposure,providing radiation resistance methods of SiC-based devices for aerospace applications.
基金the National Natural Science Foundation of China(Grant No.30270827)Project of Higher Education for Innovation and Introduction of Resourcefullness(111 Project)(Grant No.B08025)
文摘Haynaldia villosa Schur.(syn.Dasypyrum villosum Candargy,2n=14,VV)has been proved to be an important genetic resource for wheat improvement.The development of translocation with small alien chromosome segments,especially interstitial translocation,will be helpful for better utilization of its useful genes.Up to now,most of the reported Triticum aestivum–H.villosa translocation lines are involved in a whole arm or large alien fragments.In this paper,we report a highly efficient approach for the creation of small chromosome segment translocation lines.Before flowering,the female gametes of wheat-H.villosa 6VS/6AL translocation line were irradiated by 60CO-γray at 160 Rad/M dosage rate and three dosages(1600,1920,2240 Rad).Anthers were removed from the irradiated florets on the same day and the florets were pollinated with normal fresh pollens of T.aestivum cv.Chinese Spring after 2-3 days.Genomic in situ hybridization(GISH)at mitosis metaphase of root-tip cell of M1 plants was used to detect the chromosome structural changes involving 6VS of H.villosa.Among the 534 M1 plants screened,97 plants contained small segment chromosome structural changes of 6VS,including 80 interstitial translocation chromosomes,57 terminal translocation chromosomes and 55 deletion chromosomes.For the 2240 Rad dosage treatment,the inducement frequencies of interstitial translo-cation,terminal translocation and deletion were 21.02%,14.01%,and 14.65%,respectively,which were much higher than those previously reported.The M2 seeds were obtained by backcrossing of 74 M1 plants involving 146 chromosomes structural changes of 6VS,and it was found that the structural aberrations in the M1 plants could be transmitted to their progenies.Irradiating mature female gametes of whole arm translocation is a new and highly efficient approach for creation of small segment chromosome struc-tural changes,especially for interstitial translocations.
基金supported by the National Key R&D Program under Grant No.2021YFA1400500the National Natural Science Foundation of China under Grant No.22273029+1 种基金the New Cornerstone Science Foundation through the New Cornerstone Investigator Program under Grant No.NCI202303 and the XPLORER PRIZEthe Beijing Outstanding Young Scientist Program under Grant No.JWZQ20240101002。
文摘Ultrafast electron sources, which enable high spatiotemporal resolution in time-resolved electron microscopy and scanning probe microscopy, are receiving increased attention. The most widely used method for achieving ultrafast electron sources involves irradiating metal tips by ultrashort laser pulses, causing electron beam emission via the photoelectric effect [including photon-driven(quantum) or field-driven(classical) emission]. However, the thermionic electrons emission process due to the heating effect of ultrashort lasers, particularly its dynamic aspects, has rarely been addressed in previous studies. In this paper, we improved the signal-to-noise ratio of a two-pulse correlation measurement on the tip electron emission by nearly two orders of magnitude using a delay time modulation method. This allowed us to obtain information on the temperature evolution of hot electrons and phonons in a non-equilibrium state, and to extract characteristic time scales for electron-phonon and phonon-phonon scattering. Our findings indicate that the thermionic electrons emission, unlike the instantaneous photoelectric effect, causes electron emission to lag behind the laser pulse by tens of picoseconds, thus significantly affecting the detection of ultrafast dynamics of samples. Furthermore, such a lagging effect was found to be sensitive to the local structure of the metal tip, offering new insights into the improved design of ultrafast electron sources.
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supported by the National MCF En-ergy R&D Program of China(No.2022YFE03120000)the Na-tional Natural Science Foundation of China(Nos.12375266 and 12435016).
文摘Refractory high entropy alloys(RHEAs)have drawn much attention for their potential applications in ad-vanced reactors.While improved irradiation resistance to void swelling and helium bubble formation has been frequently reported,experimental investigation regarding their early-stage irradiation damage re-mains insufficient,which hinders the understanding of the behavior of point defects and small clusters.Here we select two typical RHEAs with desired mechanical properties,VTaTi and HfNbZrTi,as well as a conventional V-4Cr-4Ti alloy,and compare their irradiation-induced defect production and hardening under a low-dose irradiation to~0.1 dpa.Significant hardening is observed in V-4Cr-4Ti due to the pin-ning of deformation-induced dislocations by the high density of irradiation-induced loops.In contrast,the hardening in VTaTi is much weaker,corresponding well to the greatly reduced defect density.Strikingly,in HfNbZrTi,visible defect clusters are not observed with a Cs-corrected transmission electron microscope in the whole irradiation range,and no hardening effect is detected.Such strong suppression of irradia-tion damage is attributed to the large lattice distortion based on the ab initio calculations and the local chemical fluctuations based on the atomic-scale elemental mappings,which together hinder the mobility of interstitials.Furthermore,minor irradiation softening is evidenced by cross-sectional nanoindentation tests in HfNbZrTi,which is considered to be related to the evolution of short-range orders and interstitial impurities after irradiation.
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.
