In this study,the rotary movement of the tungsten needle in gas tungsten arc welding(GTAW)process was realized by direct current motor.The arc characteristics,the flow of molten pool and the microstructure and propert...In this study,the rotary movement of the tungsten needle in gas tungsten arc welding(GTAW)process was realized by direct current motor.The arc characteristics,the flow of molten pool and the microstructure and properties of the weld bead were studied.The results showed that the rotary motion of the tungsten needle transferred circumferential momentum to the arc as well as the molten pool,thereby conferring the latter with rotating fluid flow characteristics.Under the action of a relatively spiraling shielding gas,arc constriction occurred,and molten pool width dropped considerably.A finer and more uniform precipitated phase in the matrix,as well as a fewer large-medium pores,were achieved in the 5A06 aluminum alloy weld metal using this modified GTAW process,which noticeably increased the bending strength and tensile strength of weld metal and the microhardness of fusion zone.展开更多
Surface icing and fouling pose a substantial threat to marine facilities.Herein,anti-icing coating composites(F/S-WC-n%/F)with high photo-thermal conversion efficiencies were prepared by spraying a small amount of sup...Surface icing and fouling pose a substantial threat to marine facilities.Herein,anti-icing coating composites(F/S-WC-n%/F)with high photo-thermal conversion efficiencies were prepared by spraying a small amount of super-hydrophobic tungsten carbide on fluoro-olefin vinyl ether copolymer(FEVE)at a specific pressure.The photo-thermal properties of the coatings provide them with ice melting and sterilization effects.The delayed icing time of F/S-WC-5%/F is 571 s,with the ice-covered-surface temperature increasing to 42°C after exposure to simulated sunlight.Heat transfer modelling calculations show that icing needs to overcome high Gibbs free energy on F/S-WC-5%/F.Quantum chemistry fundamentally reveals a weak thermodynamic effect of water nucleation on F/S-WC-5%/F,indicating that the icing process requires a high degree of sub-cooling,resulting in delayed icing.In addition,F/S-WC-5%/F can resist different types of fouling and exhibit sterilization activity.Using F/S-WC-5%/F,Escherichia coli germs are killed via heat-induced morphological rupture under a solar simulator.Owing to its excellent environmental versatility,sustainability,mechanical durability and material adaptability,F/S-WC-5%/F is a promising anti-icing and anti-fouling candidate for various practical applications,even in harsh environments.展开更多
Tungsten/molybdenum alloys are widely utilized in the nuclear industry,aerospace and various other fields due to their high melting points and strength characteristics.However,poor sinterability and processability mak...Tungsten/molybdenum alloys are widely utilized in the nuclear industry,aerospace and various other fields due to their high melting points and strength characteristics.However,poor sinterability and processability make it difficult to manufacture largesize or complex-shaped parts.Hence,an in-depth study on the welding technology of tungsten/molybdenum alloys is urgent.An introduction of tungsten/molybdenum alloy welding defects and joining process was provided,along with recent advancements in brazing,spark plasma sintering diffusion bonding,electron beam welding and laser beam welding.The latest progress in alloy doping treatment applied to tungsten/molybdenum alloy dissimilar welding was also discussed,and existing welding problems were pointed out.The development prospects of weldability of tungsten/molybdenum alloy by various joining technologies were forecasted,thereby furnishing a theoretical and practical found.展开更多
Practical application of Na_(3)SbS_(4)(NSS)solid-state electrolyte in sodium metal batteries has been significantly hindered by poor interfacial stability and insufficient ionic conductivity.In this study,a series of ...Practical application of Na_(3)SbS_(4)(NSS)solid-state electrolyte in sodium metal batteries has been significantly hindered by poor interfacial stability and insufficient ionic conductivity.In this study,a series of dual-site doped Na_(3-2x)Sb_(1-x)W_(x)S_(4-x)F_(x)(x=0,0.12,0.24,0.36)electrolytes through high-energy ball milling followed by high-temperature sintering is prepared,where tungsten(W)substitutes for antimony(Sb)and fluorine(F)replaces sulfur(S)in the NSS lattice.The co-doping of W and F not only broadens the interplanar spacing of NSS but also promotes the stable formation of the cubic phase of NSS,thereby effectively enhancing the transport ability of sodium ions within NSS.Among them,Na_(2.52)Sb_(0.76)W_(0.24)S_(3.76)F_(0.24) exhibits the highest ionic conductivity of 4.45 mS·cm^(-1).Furthermore,F doping facilitates the in-situ formation of NaF between the electrolyte and metallic sodium,significantly improving interfacial stability.Electrochemical evaluation shows that the Na/Na_(2.52)Sb_(0.76)W_(0.24)S_(3.76)F_(0.24)/Na symmetric cell achieves a high critical current density of 1.65 mA·cm^(-2) and maintains stable sodium plating/stripping cycling for 500 h at 0.1 mA·cm^(-2).Additionally,the TiS2/Na_(2.52)Sb_(0.76)W_(0.24)S_(3.76)F_(0.24)/Na full cell exhibits outstanding cycling stability and rate capability.展开更多
Pure tungsten, oxide dispersion strengthened tungsten and carbide dispersion strengthened tungsten were fabricated by high-energy ball milling and spark plasma sintering process. In order to evaluate the properties of...Pure tungsten, oxide dispersion strengthened tungsten and carbide dispersion strengthened tungsten were fabricated by high-energy ball milling and spark plasma sintering process. In order to evaluate the properties of the tungsten alloys under transient high heat flues, four tungsten samples with different grain sizes were tested by high-intensity pulsed ion beam with a heat flux as high as 160 MW/（m^2·s^-1/2）. Compared with the commercial tungsten, the surface modification of the oxide dispersion strengthened tungsten by high-intensity pulsed ion beam is completely different. The oxide dispersion strengthened tungsten shows inferior thermal shock response due to the low melting point second phase of Ti and Y2O3, which results in the surface melting, boiling bubbles and cracking. While the carbide dispersion strengthened tungsten shows better thermal shock response than the commercial tungsten.展开更多
Rapid adsorption of radioactive substances is of great significance in emergency situations.A novel approach combining S-defect introduction and in situ phosphorization was employed to synthesize phosphorized WS_(2)(W...Rapid adsorption of radioactive substances is of great significance in emergency situations.A novel approach combining S-defect introduction and in situ phosphorization was employed to synthesize phosphorized WS_(2)(WS_(2)-PO_(4))for ultra-efficient uranium extraction.At an initial U(VI)concentration of 50 mg·L^(-1),the adsorption of U(VI)by WS_(2)-PO_(4) nanosheets exceeds77%within just 1 min,with high selectivity(SU=78.7%)and good adsorption capacity of 268.82 mg·g^(-1).The phosphate groups have grown on the S defects and taken part in U(VI)extraction through surface complexation,leading to fast,reusable,and highly selective uranium adsorption,showing great potential in emergency treatment of radioactive nuclear wastewater.展开更多
The effects of potassium(K)doping on the incipient plasticity of tungsten(W)under nanoindentation were investigated using a combination of experiments and mesoscale defects dynamic simulations.The transmission electro...The effects of potassium(K)doping on the incipient plasticity of tungsten(W)under nanoindentation were investigated using a combination of experiments and mesoscale defects dynamic simulations.The transmission electron microscopy study reveal that nanometer-sized bubbles were formed through the vaporization of K in specimens prepared by spark plasma sintering.In order to investigate the mechanical properties of the K-doped W specimens,nano-characterization experiments and defect dynamics simula-tions were conducted,comparing with those in pure W.Nanoindentation tests reveal that the maximum shear yield stress approaches the theoretical strength in annealed pure W,while K-doped W samples exhibit significant yield drop accompanied with stochastic variations.A newly developed mesoscale defect dynamics model to concurrently couple dislocation dynamics with finite element method has been also employed to investigate micro-mechanisms of plasticity under nanoindentation and the effects of K-bubbles on the plastic deformation.The simulations revealed that the localized stress concentration induced by the K-bubbles promoted dislocation nucleation and enhanced plastic deformation,thereby reducing the yield stress,showing good agreement with the experiment.展开更多
The photochemical conversion of plastic waste into valuable resources under ambient conditions is challenging.Achieving efficient photocatalytic conversion necessitates intimate contact between the photocatalyst and p...The photochemical conversion of plastic waste into valuable resources under ambient conditions is challenging.Achieving efficient photocatalytic conversion necessitates intimate contact between the photocatalyst and plastic substrate,as water molecules are readily oxidized by photogenerated holes,potentially bypassing the plastic as the electron donor.This study demonstrated a novel strategy for depositing polystyrene(PS)waste onto a photoanode by leveraging its solubility in specific organic solvents,including acetone and chloroform,thus enhancing the interface contact.We used an anodization technique to fabricate a skeleton-like porous tungsten oxide(WO_(3))structure,which exhibited higher durability against detachment from a conductive substrate than the WO_(3) photoanode fabricated using the doctor blade method.Upon illumination,the photogenerated holes were transferred from WO_(3) to PS,promoting the oxidative degradation of plastic waste under ambient conditions.Consequently,the oxidative degradation of PS on the anode side generated carbon dioxide,while the cathodic process produced hydrogen gas through water reduction.Our findings pave the way for sunlight-driven plastic waste treatment technologies that concurrently generate valuable fuels or chemicals and offer the dual benefits of cost savings and environmental protection.展开更多
The thermal conductivity of plasma-facing materials(PFM)exposed to intense radiation is a critical concern for the reliable usage of materials in fusion reactors.However,limited research has been performed regarding t...The thermal conductivity of plasma-facing materials(PFM)exposed to intense radiation is a critical concern for the reliable usage of materials in fusion reactors.However,limited research has been performed regarding the thermal conductivity of structures that rapidly change in a short time during collision cascade processes under irradiation.In this study,we employed the tight-binding(TB)method to investigate the electronic thermal conductivity(κ_(e))of tungsten-based systems during various cascading processes.We found thatκ_(e) values sharply decrease within the initial 0.3 picoseconds and then partially recover at a slow pace;this is closely linked to the evolution of defects and microstructural distortions.The increase in the initial kinetic energy of the primary knock-on atom and the presence of a high concentration of hydrogen atoms further decrease theκ_(e) values.Conversely,higher temperatures have a significant positive effect onκ_(e).Furthermore,the presence of a grain boundary∑5[001](130)substantially reducesκ_(e),whereas the absorption effect of point defects by the grain boundary has little influence onκ_(e) during cascades.Our findings provide a theoretical basis for evaluating changes in the thermal conductivity performance of PFMs during their usage in nuclear fusion reactors.展开更多
Using molecular dynamics methods,simulations of collision cascades in polycrystalline tungsten(W)have been conducted in this study,including different primary-knock-on atom(PKA)directions,grain sizes,and PKA energies ...Using molecular dynamics methods,simulations of collision cascades in polycrystalline tungsten(W)have been conducted in this study,including different primary-knock-on atom(PKA)directions,grain sizes,and PKA energies between 1 keV and 150 keV.The results indicate that a smaller grain size leads to more defects forming in grain boundary regions during cascade processes.The impact of high-energy PKA may cause a certain degree of distortion of the grain boundaries,which has a higher probability in systems with smaller grain sizes and becomes more pronounced as the PKA energy increases.The direction of PKA can affect the formation and diffusion pathways of defects.When the PKA direction is perpendicular to the grain boundary,defects preferentially form near the grain boundary regions;by contrast,defects are more inclined to form in the interior of the grains.These results are of great significance for comprehending the changes in the performance of polycrystalline W under the high-energy fusion environments and can provide theoretical guidance for further optimization and application of W-based plasma materials.展开更多
The distribution and competitive behaviors of phosphotungstic acid and ferric chloride in the TBP-HCl-H_(2)O system were investigated by controlling the extractant concentration and the solution environment.The result...The distribution and competitive behaviors of phosphotungstic acid and ferric chloride in the TBP-HCl-H_(2)O system were investigated by controlling the extractant concentration and the solution environment.The results revealed that phosphotungstic acid exhibited a strong affinity for TBP with decreasing TBP concentration.Higher acidity significantly improved the W extraction efficiency with TBP,and the lower Cl^(-)concentration reduced the extraction efficiency of Fe.As the organic phase approached saturation point,phosphotungstic acid competitively displaced Fe to combine with TBP.The hydrogen bond structure(P=O·HO-P-W-O)between phosphotungstic acid and TBP was characterized by FT-IR,and the salting-out effect induced by FeCl_(3) was elucidated.In summary,high acidity is beneficial for exhaustive extraction of W,and an effective W/Fe separation can be achieved by reducing the concentrations of TBP and Cl^(-).展开更多
Tungsten(W)is considered a critical and strategic material,the recycling of which has proved extremely important due to the substantial amount of W-rich waste and rising demand for W products.This study provides a sou...Tungsten(W)is considered a critical and strategic material,the recycling of which has proved extremely important due to the substantial amount of W-rich waste and rising demand for W products.This study provides a sound technological approach for efficient utilization of bulk W,achieving a high W destruction rate(rw)of 0.3 g·cm^(-2)·h^(-1)via electrochemical oxidation/in situ reduction of W electrodes in oxalic acid under alternating current(AC)with varying symmetries to synthesize WO_(3-x)nanopowders(NPs).Amorphous-crystalline dual-phase reduced WO_(3-x)NPs featuring dense and porous nanoarchitectures were synthesized using asymmetrical and symmetrical AC,respectively.The nano scale interconnecting flaky WO_(3-x)structure arises from the synergy of high anodic voltage etching and the release of H_(2)microbubbles,boosting the exfoliation of WO_(3)flakes.The optimized WO_(3-x)NP exhibits superior electrochemical and electrochromic properties,attributed to the increased surface capacitance alongside an extra contribution from intercalation pseudocapacitance.The number of WO_(3-x)layers deposited by the spin coating technique and the annealing temperature have a significant impact on the electrochemical and electrochromic characteristics of the WO_(3)film.An increase in the transferred charge density(Q),coloring/bleaching time(t_(c)/t_(b))values,and areal capacitance was observed,alongside a decrease in optical modulation(ΔT)and coloration efficiency(CE)with an increasing number of WO_(3)layers.WO_(3)produced at a lower temperature outperforms WO_(3)treated at 400-500℃,particularly in fast switching,enhanced efficiency,and reversibility.TheΔT of 68.7%,CE of 47.9 cm^(2)·C^(-1),areal capacitance of 53.5 mF·cm^(-2),and reversibility close to 100%were achieved in H_(2)SO_(4)for the optimized WO_(3-x)film.The research aligns with the ongoing development strategy of the circular economy and validates the promising features of the efficient recycling of W-containing spent resources through an environmentally sustainable electrochemical approach.展开更多
A high-quality welding method,named plasma arc welding apparatus with rotating tungsten electrode(abbreviated as PAW-RT),was proposed in this paper.The rotation speed could be adjusted from 0 to 15000 r/min.The rotary...A high-quality welding method,named plasma arc welding apparatus with rotating tungsten electrode(abbreviated as PAW-RT),was proposed in this paper.The rotation speed could be adjusted from 0 to 15000 r/min.The rotary motion of the tungsten needle trans-ferred circumferential momentum to the arc as well as the molten pool,thereby conferring the latter with rotating fluid flow charac-teristics.The influences of tungsten electrode rotation speed on PAW arc morphology,weld formation and interfacial microstructure of the final weld joints were discussed by the experimental procedures involving in-situ ablation,surfacing and butt welding.The ex-periments were conducted on Q235B steel.The results indicated that the increase of tungsten electrode rotation speed in PAW-RT contributed to improving arc eccentricity,leading to aesthetically improved welds with more uniformity.Additionally,the strength,hardness and toughness of the welded joint increased,while porosity was reduced.展开更多
Wearable sensors are pivotal for point-of-care diagnostics,yet their application in extreme conditions is rarely conducted.In this work,we present a wearable pH sensor using tungsten oxide aerogel(TOA)as the sensing m...Wearable sensors are pivotal for point-of-care diagnostics,yet their application in extreme conditions is rarely conducted.In this work,we present a wearable pH sensor using tungsten oxide aerogel(TOA)as the sensing material.With the advantages of large specific surface area,high porosity and interconnected network structures,TOA not only provides excellent pH sensing performance but also demonstrates remarkable structural and sensing stability.The potentiometric pH sensor exhibits a high sensitivity(−63.70 mV/pH),a low detectable limit(0.05)and a superior stability(maintained over 50,000 s).Integrated with a Bluetooth module,the wearable sensor achieves non-invasive and real-time pH monitoring on the human skin with minimal deviation(1.91%)compared to the commercial pH meter.More importantly,the anti-impact behaviors of the TOA-based sensing materials and chip,along with the pH wearable sensor on a pig exhibit an outstanding shock-resistance ability,with variations no more than 7.17%under an impact of 118.38 kPa.Therefore,this study shows great promise for the aerogel-based personalized health management in the extreme environment.展开更多
Heterostructures of organic semi-conductors and transition metal dichalcogenides(TMDs)are viable candidates for superior optoelec-tronic devices.Photoinduced inter-facial charge transfer is crucial for the performance...Heterostructures of organic semi-conductors and transition metal dichalcogenides(TMDs)are viable candidates for superior optoelec-tronic devices.Photoinduced inter-facial charge transfer is crucial for the performance efficiency of such devices,yet the underlying mecha-nism,especially the roles of optical-ly dark triplets and spatially sepa-rated charge transfer states,is poorly understood.In the present work,we obtain the struc-tures of distinct excited states and investigate how they are involved in the charge transfer process at the Pd-octaethylporphyrin(PdOEP)and WS_(2) interface in terms of their energies and couplings.The results show that electron transfer from the triplet PdOEP formed via intersystem crossing prevails over direct electron transfer from the singlet(two orders of magnitude faster).Further analysis reveals that the relatively higher rate of triplet electron transfer compared to singlet electron transfer is mainly attributed to a smaller reorganization energy,which is dominated by the out-of-plane vibrations of the organic component.The work emphasizes the important roles of the optically dark triplets in the electron transfer of the PdOEP@WS_(2) heterostructure,and provides valuable theoretical insights for further improv-ing the optoelectronic performance of TMD-based devices.展开更多
Semiconducting transition-metal dichalcogenides(TMDs)have garnered significant interest due to their unique structures and properties,positioning them as promising candidates for novel electronic and optoelectronic de...Semiconducting transition-metal dichalcogenides(TMDs)have garnered significant interest due to their unique structures and properties,positioning them as promising candidates for novel electronic and optoelectronic devices.However,the performance of TMDs-based devices is hampered by the suboptimal quality of metal electrodes contacting the atomically thin TMDs layers.Understanding the mechanisms that influence contact quality is crucial for advancing TMDs devices.In this study,we investigated the conductive properties of tungsten selenide(WSe_(2))-based devices with different film thicknesses.Using the transmission line method,a negative correlation between contact resistance and film thickness in multi-electrode devices was revealed.Additionally,repeatability tests conducted at varied temperatures indicated enhanced device stability with increasing film thickness.Theoretical analysis,supported by thermionic emission theory and thermal simulations,suggests that the degradation in electrical properties is primarily due to the thermal effect at the contact interface.Furthermore,we found that van der Waals contacts could mitigate the thermal effect through a metal transfer method.Our findings elucidate the critical role of contact resistance in the electronic performance of 2D material-based field-effect transistors(FETs),which further expands their potential in the next generation of electronic and optoelectronic devices.展开更多
Neutral oxygen evolution reaction(OER)is a crucial half-reaction for electrocatalytic chemical production under mild condition,but with limited development due to low activity and poor stability.Herein,a tungsten-dope...Neutral oxygen evolution reaction(OER)is a crucial half-reaction for electrocatalytic chemical production under mild condition,but with limited development due to low activity and poor stability.Herein,a tungsten-doped cobalt molybdate(WDCMO)catalyst was synthesized for efficient and durable OER under neutral electrolyte.It is demonstrated that catalyst reconstruction is suppressed by W doping,which stabilizes the Co-O-Mo point-to-point connection in CoMoO_(4) architecture and stimulates to a lower valence state of active sites over the surface phase.Thereby,the surface structure maintains to avoid compound dissolution caused by over-oxidation during OER.Meanwhile,the WDCMO catalyst promotes charge transfer and optimizes*OH intermediate adsorption,which improves reaction kinetics and intrinsic activity.Consequently,the WDCMO electrode exhibits an overpotential of 302 mV at 10 mA cm^(-2) in neutral electrolyte with an improvement of 182 mV compared with CoMoO4 electrode.Furthermore,W doping significantly improves the electrode stability from 50 h to more than 320 h,with a suppressive potential attenuation from 2.82 to 0.29 mV h^(-1).This work will shed new light on designing rational electrocatalysts for neutral OER.展开更多
Quartz vein-type tungsten deposits are a common W deposit type.Their ore vein distribution was previously considered to be controlled by regional horizontal tectonic stress.In this paper,14 tungsten deposits with fan-...Quartz vein-type tungsten deposits are a common W deposit type.Their ore vein distribution was previously considered to be controlled by regional horizontal tectonic stress.In this paper,14 tungsten deposits with fan-shaped mineralization in SE China are summarized,and the relations between their ore veins and granite and the ore-forming structural stress field are analyzed.These deposits have a post-magmatic hydrothermal genesis and involve the formation of two sets of veins with similar strike and opposite dips at the top of the ore-causative granite bodies,forming a vertical fan-shaped profile.Their ore veins were coeval with the underlying granite bodies,and generally extend along the long axis of the granite.In such fan-shaped ore formation,the stress is highly focused at the top of the granite and gradually weakens outward.The maximum principal stress(σ1)is perpendicular to the granite contact surface,and radiates outward from the pluton.Meanwhile,the minimum principal stress(σ3)forms an arc-shaped band parallel to the contact surface.Our findings,together with published numerical modeling indicate that the emplacement dynamics of granitic magma(rather than regional horizontal tectonic stress)are essential controls on the distribution of ore veins in quartz vein-type tungsten deposits.展开更多
Si-containing Mg alloys solidified at conventional rates often contain coarse and sharp Mg_(2)Si phases,which can result in inferior material properties.In this study,Mg-6wt.%Si(Mg-6Si)alloy was prepared by wire arc a...Si-containing Mg alloys solidified at conventional rates often contain coarse and sharp Mg_(2)Si phases,which can result in inferior material properties.In this study,Mg-6wt.%Si(Mg-6Si)alloy was prepared by wire arc additive manufacturing(WAAM),employing the gas tungsten arc welding technique with rapid cooling.The microstructures and mechanical properties of the WAAM alloy were investigated and compared with those of the as-cast samples produced using a metal mold.The results indicate that the WAAM Mg-6Si is harder and stronger than the as-cast samples.The microhardness of the WAAM Mg-6Si increases by 36.6% in comparison to that of as-cast Mg-6Si alloy.Furthermore,the average tensile strengths at room temperature and 150℃ increases by 63.4% and 21.3%,respectively.WAAM refines both the Mg_(2)Si phase and the overall grains,resulting in a homogeneous morphology and improved mechanical properties.The granular Mg_(2)Si phase,characterized by fine particles with a diffused distribution,shows a significant increase in concentration.The acicular Mg_(2)Si phase is distributed along the grain boundaries,and its concentration significantly decreases.The average grain size of the Mg_(2)Si phase is about 9.20μm,about 5 times smaller.The refinement and distribution of the granular Mg_(2)Si phase,as well as the reduction in the amount of needle-like Mg_(2)Si particles,are the key factors for improving the mechanical properties of WAAM Mg-6Si alloy.展开更多
Tungsten is considered the most promising plasma-facing material for fusion reactors with exceptional performance.Under certain conditions,activated tungsten dust can be generated through plasma–wall interactions and...Tungsten is considered the most promising plasma-facing material for fusion reactors with exceptional performance.Under certain conditions,activated tungsten dust can be generated through plasma–wall interactions and released into the atmosphere.Activated tungsten migrates downward in the soil after atmospheric deposition.However,effective methods for evaluating the environmental dose of gamma rays emitted by activated tungsten are still lacking.Consequently,a method for evaluating the air-absorbed dose rate of activated tungsten dust was proposed considering soil attenuation.Key parameters including the mass attenuation coefficient and energy absorption build-up factor were determined for the main gamma ray energies of radionuclides within the activated tungsten dust.Additionally,air-absorbed dose rates were calculated by assuming that radioactive sources were located at different soil depths and radii.It was found that a soil depth of 50 cm significantly attenuated the environmental dose by 99.9%,whereas the air-absorbed dose rates within the horizontal distance of 500 cm accounted for 91%of the total dose rate.Therefore,this study underscored the importance of soil attenuation in environmental dose assessments,which must be carefully re-examined for the safety analysis of fusion reactors.展开更多
基金supported by National Natural Science Foundation of China(52175305)National Natural Science Foundation of China(U22B20127)Taishan Scholars Project(tstp20230618).
文摘In this study,the rotary movement of the tungsten needle in gas tungsten arc welding(GTAW)process was realized by direct current motor.The arc characteristics,the flow of molten pool and the microstructure and properties of the weld bead were studied.The results showed that the rotary motion of the tungsten needle transferred circumferential momentum to the arc as well as the molten pool,thereby conferring the latter with rotating fluid flow characteristics.Under the action of a relatively spiraling shielding gas,arc constriction occurred,and molten pool width dropped considerably.A finer and more uniform precipitated phase in the matrix,as well as a fewer large-medium pores,were achieved in the 5A06 aluminum alloy weld metal using this modified GTAW process,which noticeably increased the bending strength and tensile strength of weld metal and the microhardness of fusion zone.
基金supported by the Heilongjiang Province Key Research and Development Program(No.2023ZX07D04)the Fundamental Research Funds for Central Universities and the State Key Laboratory of Marine Coating.
文摘Surface icing and fouling pose a substantial threat to marine facilities.Herein,anti-icing coating composites(F/S-WC-n%/F)with high photo-thermal conversion efficiencies were prepared by spraying a small amount of super-hydrophobic tungsten carbide on fluoro-olefin vinyl ether copolymer(FEVE)at a specific pressure.The photo-thermal properties of the coatings provide them with ice melting and sterilization effects.The delayed icing time of F/S-WC-5%/F is 571 s,with the ice-covered-surface temperature increasing to 42°C after exposure to simulated sunlight.Heat transfer modelling calculations show that icing needs to overcome high Gibbs free energy on F/S-WC-5%/F.Quantum chemistry fundamentally reveals a weak thermodynamic effect of water nucleation on F/S-WC-5%/F,indicating that the icing process requires a high degree of sub-cooling,resulting in delayed icing.In addition,F/S-WC-5%/F can resist different types of fouling and exhibit sterilization activity.Using F/S-WC-5%/F,Escherichia coli germs are killed via heat-induced morphological rupture under a solar simulator.Owing to its excellent environmental versatility,sustainability,mechanical durability and material adaptability,F/S-WC-5%/F is a promising anti-icing and anti-fouling candidate for various practical applications,even in harsh environments.
基金National Natural Science Foundation of China(52071165,52475347)National Program of Foreign Experts of China(G2023026003L)+4 种基金China Postdoctoral Fund(2023M740475)Program for Science&Technology Innovation Talents in Universities of Henan Province,China(22HASTIT026)Program for the Top Young Talents of Henan Province,China,Frontier Exploration Projects of Longmen Laboratory,China(LMQYTSKT016)Key Scientific Research Projects of Colleges and Universities in Henan Province,China(24A460008)Key Science and Technology Project of Henan Province,China(242102220064,222102230111)。
文摘Tungsten/molybdenum alloys are widely utilized in the nuclear industry,aerospace and various other fields due to their high melting points and strength characteristics.However,poor sinterability and processability make it difficult to manufacture largesize or complex-shaped parts.Hence,an in-depth study on the welding technology of tungsten/molybdenum alloys is urgent.An introduction of tungsten/molybdenum alloy welding defects and joining process was provided,along with recent advancements in brazing,spark plasma sintering diffusion bonding,electron beam welding and laser beam welding.The latest progress in alloy doping treatment applied to tungsten/molybdenum alloy dissimilar welding was also discussed,and existing welding problems were pointed out.The development prospects of weldability of tungsten/molybdenum alloy by various joining technologies were forecasted,thereby furnishing a theoretical and practical found.
文摘Practical application of Na_(3)SbS_(4)(NSS)solid-state electrolyte in sodium metal batteries has been significantly hindered by poor interfacial stability and insufficient ionic conductivity.In this study,a series of dual-site doped Na_(3-2x)Sb_(1-x)W_(x)S_(4-x)F_(x)(x=0,0.12,0.24,0.36)electrolytes through high-energy ball milling followed by high-temperature sintering is prepared,where tungsten(W)substitutes for antimony(Sb)and fluorine(F)replaces sulfur(S)in the NSS lattice.The co-doping of W and F not only broadens the interplanar spacing of NSS but also promotes the stable formation of the cubic phase of NSS,thereby effectively enhancing the transport ability of sodium ions within NSS.Among them,Na_(2.52)Sb_(0.76)W_(0.24)S_(3.76)F_(0.24) exhibits the highest ionic conductivity of 4.45 mS·cm^(-1).Furthermore,F doping facilitates the in-situ formation of NaF between the electrolyte and metallic sodium,significantly improving interfacial stability.Electrochemical evaluation shows that the Na/Na_(2.52)Sb_(0.76)W_(0.24)S_(3.76)F_(0.24)/Na symmetric cell achieves a high critical current density of 1.65 mA·cm^(-2) and maintains stable sodium plating/stripping cycling for 500 h at 0.1 mA·cm^(-2).Additionally,the TiS2/Na_(2.52)Sb_(0.76)W_(0.24)S_(3.76)F_(0.24)/Na full cell exhibits outstanding cycling stability and rate capability.
基金roject (50634060) supported by the National Natural Science Foundation of ChinaProject (2010GB109000) supported by the National Basic Research Program of China
文摘Pure tungsten, oxide dispersion strengthened tungsten and carbide dispersion strengthened tungsten were fabricated by high-energy ball milling and spark plasma sintering process. In order to evaluate the properties of the tungsten alloys under transient high heat flues, four tungsten samples with different grain sizes were tested by high-intensity pulsed ion beam with a heat flux as high as 160 MW/（m^2·s^-1/2）. Compared with the commercial tungsten, the surface modification of the oxide dispersion strengthened tungsten by high-intensity pulsed ion beam is completely different. The oxide dispersion strengthened tungsten shows inferior thermal shock response due to the low melting point second phase of Ti and Y2O3, which results in the surface melting, boiling bubbles and cracking. While the carbide dispersion strengthened tungsten shows better thermal shock response than the commercial tungsten.
基金supported by the National Key Laboratory of Uranium Resources Exploration-Mining and Nuclear Remote Sensing(No.2024QZ-KF-05)the National Natural Science Foundation of China(Nos.U24A20194,22366006)+2 种基金Key R&D Program of Jiangxi Province(No.20243BBG71020)Natural Science Foundation of Jiangxi province(Nos.20224BAB213027,20242BAB20109)the Academic and Technical Leaders Training Program of Jiangxi Province(Nos.20212BCJL23046,20212BCJL23047)。
文摘Rapid adsorption of radioactive substances is of great significance in emergency situations.A novel approach combining S-defect introduction and in situ phosphorization was employed to synthesize phosphorized WS_(2)(WS_(2)-PO_(4))for ultra-efficient uranium extraction.At an initial U(VI)concentration of 50 mg·L^(-1),the adsorption of U(VI)by WS_(2)-PO_(4) nanosheets exceeds77%within just 1 min,with high selectivity(SU=78.7%)and good adsorption capacity of 268.82 mg·g^(-1).The phosphate groups have grown on the S defects and taken part in U(VI)extraction through surface complexation,leading to fast,reusable,and highly selective uranium adsorption,showing great potential in emergency treatment of radioactive nuclear wastewater.
基金supported by the Nano&Material Technology Development Program through the National Research Foundation of Korea(NRF)funded by Ministry of Science and ICT(No.RS-2024-00445448)the National Research Foundation of Korea(NRF)funded by the Ministry of Science(No.NRF-2021R1A2C3005096)the ITER Technology R&D Program.
文摘The effects of potassium(K)doping on the incipient plasticity of tungsten(W)under nanoindentation were investigated using a combination of experiments and mesoscale defects dynamic simulations.The transmission electron microscopy study reveal that nanometer-sized bubbles were formed through the vaporization of K in specimens prepared by spark plasma sintering.In order to investigate the mechanical properties of the K-doped W specimens,nano-characterization experiments and defect dynamics simula-tions were conducted,comparing with those in pure W.Nanoindentation tests reveal that the maximum shear yield stress approaches the theoretical strength in annealed pure W,while K-doped W samples exhibit significant yield drop accompanied with stochastic variations.A newly developed mesoscale defect dynamics model to concurrently couple dislocation dynamics with finite element method has been also employed to investigate micro-mechanisms of plasticity under nanoindentation and the effects of K-bubbles on the plastic deformation.The simulations revealed that the localized stress concentration induced by the K-bubbles promoted dislocation nucleation and enhanced plastic deformation,thereby reducing the yield stress,showing good agreement with the experiment.
基金supported by the National Research Foundation of Korea(NRF)funded by the Ministry of Science and Information and Communication Technology(ICT)(NRF-2020M3H4A3106354)Korea Government(MSIT,RS-2023-00213022)the Korea Institution of Science and Technology(KIST)internal projects.
文摘The photochemical conversion of plastic waste into valuable resources under ambient conditions is challenging.Achieving efficient photocatalytic conversion necessitates intimate contact between the photocatalyst and plastic substrate,as water molecules are readily oxidized by photogenerated holes,potentially bypassing the plastic as the electron donor.This study demonstrated a novel strategy for depositing polystyrene(PS)waste onto a photoanode by leveraging its solubility in specific organic solvents,including acetone and chloroform,thus enhancing the interface contact.We used an anodization technique to fabricate a skeleton-like porous tungsten oxide(WO_(3))structure,which exhibited higher durability against detachment from a conductive substrate than the WO_(3) photoanode fabricated using the doctor blade method.Upon illumination,the photogenerated holes were transferred from WO_(3) to PS,promoting the oxidative degradation of plastic waste under ambient conditions.Consequently,the oxidative degradation of PS on the anode side generated carbon dioxide,while the cathodic process produced hydrogen gas through water reduction.Our findings pave the way for sunlight-driven plastic waste treatment technologies that concurrently generate valuable fuels or chemicals and offer the dual benefits of cost savings and environmental protection.
基金supported by the Collaborative Innovation Program of Hefei Science Center of CAS(No.2022HSC-CIP007)。
文摘The thermal conductivity of plasma-facing materials(PFM)exposed to intense radiation is a critical concern for the reliable usage of materials in fusion reactors.However,limited research has been performed regarding the thermal conductivity of structures that rapidly change in a short time during collision cascade processes under irradiation.In this study,we employed the tight-binding(TB)method to investigate the electronic thermal conductivity(κ_(e))of tungsten-based systems during various cascading processes.We found thatκ_(e) values sharply decrease within the initial 0.3 picoseconds and then partially recover at a slow pace;this is closely linked to the evolution of defects and microstructural distortions.The increase in the initial kinetic energy of the primary knock-on atom and the presence of a high concentration of hydrogen atoms further decrease theκ_(e) values.Conversely,higher temperatures have a significant positive effect onκ_(e).Furthermore,the presence of a grain boundary∑5[001](130)substantially reducesκ_(e),whereas the absorption effect of point defects by the grain boundary has little influence onκ_(e) during cascades.Our findings provide a theoretical basis for evaluating changes in the thermal conductivity performance of PFMs during their usage in nuclear fusion reactors.
基金Project supported by the National MCF Energy Research and Development Program of China(Grant No.2018YFE0308101)the National Key Research and Development Program of China(Grant No.2018YFB0704000)+1 种基金the Suqian Science and Technology Program(Grant No.K202337)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(Grant No.23KJD490001).
文摘Using molecular dynamics methods,simulations of collision cascades in polycrystalline tungsten(W)have been conducted in this study,including different primary-knock-on atom(PKA)directions,grain sizes,and PKA energies between 1 keV and 150 keV.The results indicate that a smaller grain size leads to more defects forming in grain boundary regions during cascade processes.The impact of high-energy PKA may cause a certain degree of distortion of the grain boundaries,which has a higher probability in systems with smaller grain sizes and becomes more pronounced as the PKA energy increases.The direction of PKA can affect the formation and diffusion pathways of defects.When the PKA direction is perpendicular to the grain boundary,defects preferentially form near the grain boundary regions;by contrast,defects are more inclined to form in the interior of the grains.These results are of great significance for comprehending the changes in the performance of polycrystalline W under the high-energy fusion environments and can provide theoretical guidance for further optimization and application of W-based plasma materials.
基金supported by the National key R&D Program of China(No.2022YFC2905105)the National Natural Science Foundation of China(No.72088101)。
文摘The distribution and competitive behaviors of phosphotungstic acid and ferric chloride in the TBP-HCl-H_(2)O system were investigated by controlling the extractant concentration and the solution environment.The results revealed that phosphotungstic acid exhibited a strong affinity for TBP with decreasing TBP concentration.Higher acidity significantly improved the W extraction efficiency with TBP,and the lower Cl^(-)concentration reduced the extraction efficiency of Fe.As the organic phase approached saturation point,phosphotungstic acid competitively displaced Fe to combine with TBP.The hydrogen bond structure(P=O·HO-P-W-O)between phosphotungstic acid and TBP was characterized by FT-IR,and the salting-out effect induced by FeCl_(3) was elucidated.In summary,high acidity is beneficial for exhaustive extraction of W,and an effective W/Fe separation can be achieved by reducing the concentrations of TBP and Cl^(-).
基金supported by the Russian Science Foundation(No.23-79-10219),https://rscf.ru/en/project/23-79-10219/)。
文摘Tungsten(W)is considered a critical and strategic material,the recycling of which has proved extremely important due to the substantial amount of W-rich waste and rising demand for W products.This study provides a sound technological approach for efficient utilization of bulk W,achieving a high W destruction rate(rw)of 0.3 g·cm^(-2)·h^(-1)via electrochemical oxidation/in situ reduction of W electrodes in oxalic acid under alternating current(AC)with varying symmetries to synthesize WO_(3-x)nanopowders(NPs).Amorphous-crystalline dual-phase reduced WO_(3-x)NPs featuring dense and porous nanoarchitectures were synthesized using asymmetrical and symmetrical AC,respectively.The nano scale interconnecting flaky WO_(3-x)structure arises from the synergy of high anodic voltage etching and the release of H_(2)microbubbles,boosting the exfoliation of WO_(3)flakes.The optimized WO_(3-x)NP exhibits superior electrochemical and electrochromic properties,attributed to the increased surface capacitance alongside an extra contribution from intercalation pseudocapacitance.The number of WO_(3-x)layers deposited by the spin coating technique and the annealing temperature have a significant impact on the electrochemical and electrochromic characteristics of the WO_(3)film.An increase in the transferred charge density(Q),coloring/bleaching time(t_(c)/t_(b))values,and areal capacitance was observed,alongside a decrease in optical modulation(ΔT)and coloration efficiency(CE)with an increasing number of WO_(3)layers.WO_(3)produced at a lower temperature outperforms WO_(3)treated at 400-500℃,particularly in fast switching,enhanced efficiency,and reversibility.TheΔT of 68.7%,CE of 47.9 cm^(2)·C^(-1),areal capacitance of 53.5 mF·cm^(-2),and reversibility close to 100%were achieved in H_(2)SO_(4)for the optimized WO_(3-x)film.The research aligns with the ongoing development strategy of the circular economy and validates the promising features of the efficient recycling of W-containing spent resources through an environmentally sustainable electrochemical approach.
基金supported by the National Natural Science Foundation of China(U22B20127)the National Natural Science Foundation of China(52175305)Taishan Scholars Project(tstp20230618).
文摘A high-quality welding method,named plasma arc welding apparatus with rotating tungsten electrode(abbreviated as PAW-RT),was proposed in this paper.The rotation speed could be adjusted from 0 to 15000 r/min.The rotary motion of the tungsten needle trans-ferred circumferential momentum to the arc as well as the molten pool,thereby conferring the latter with rotating fluid flow charac-teristics.The influences of tungsten electrode rotation speed on PAW arc morphology,weld formation and interfacial microstructure of the final weld joints were discussed by the experimental procedures involving in-situ ablation,surfacing and butt welding.The ex-periments were conducted on Q235B steel.The results indicated that the increase of tungsten electrode rotation speed in PAW-RT contributed to improving arc eccentricity,leading to aesthetically improved welds with more uniformity.Additionally,the strength,hardness and toughness of the welded joint increased,while porosity was reduced.
基金supported by the National Natural Science Foundation of China(Nos.22374119 and 22274127)the Research Fund of the State Key Laboratory of Solidification Processing(NPU),China(No.2021-QZ-01)+1 种基金the Key Project of Natural Science Fund of Shaanxi Province(Nos.2023-JC-ZD-06 and 2024JC-YBQN-0636)the Open Project of the State Key Laboratory of Transducer Technology(No.SKT2307).
文摘Wearable sensors are pivotal for point-of-care diagnostics,yet their application in extreme conditions is rarely conducted.In this work,we present a wearable pH sensor using tungsten oxide aerogel(TOA)as the sensing material.With the advantages of large specific surface area,high porosity and interconnected network structures,TOA not only provides excellent pH sensing performance but also demonstrates remarkable structural and sensing stability.The potentiometric pH sensor exhibits a high sensitivity(−63.70 mV/pH),a low detectable limit(0.05)and a superior stability(maintained over 50,000 s).Integrated with a Bluetooth module,the wearable sensor achieves non-invasive and real-time pH monitoring on the human skin with minimal deviation(1.91%)compared to the commercial pH meter.More importantly,the anti-impact behaviors of the TOA-based sensing materials and chip,along with the pH wearable sensor on a pig exhibit an outstanding shock-resistance ability,with variations no more than 7.17%under an impact of 118.38 kPa.Therefore,this study shows great promise for the aerogel-based personalized health management in the extreme environment.
基金supported by the Fundamental Re-search Funds for the Central Universities(Ganglong Cui)and National Key Research and Development Pro-gram of China(No.2021YFA1500703 to Ganglong Cui)National Natural Science Foundation of China(No.22103067 to Xiao-Ying Xie)and Natural Science Foundation of Shandong Province(No.ZR2021QB105 to Xiao-Ying Xie).
文摘Heterostructures of organic semi-conductors and transition metal dichalcogenides(TMDs)are viable candidates for superior optoelec-tronic devices.Photoinduced inter-facial charge transfer is crucial for the performance efficiency of such devices,yet the underlying mecha-nism,especially the roles of optical-ly dark triplets and spatially sepa-rated charge transfer states,is poorly understood.In the present work,we obtain the struc-tures of distinct excited states and investigate how they are involved in the charge transfer process at the Pd-octaethylporphyrin(PdOEP)and WS_(2) interface in terms of their energies and couplings.The results show that electron transfer from the triplet PdOEP formed via intersystem crossing prevails over direct electron transfer from the singlet(two orders of magnitude faster).Further analysis reveals that the relatively higher rate of triplet electron transfer compared to singlet electron transfer is mainly attributed to a smaller reorganization energy,which is dominated by the out-of-plane vibrations of the organic component.The work emphasizes the important roles of the optically dark triplets in the electron transfer of the PdOEP@WS_(2) heterostructure,and provides valuable theoretical insights for further improv-ing the optoelectronic performance of TMD-based devices.
基金supported by the Science and Technology Innovation Council of Shenzhen(No.KQTD20170810105439418)the National Key R&D Project from Minister of Science and Technology,China(No.2021YFB3200304)+2 种基金National Natural Science Foundation of China(Nos.6237129,52125205,U20A20166,61805015 and 61804011)the Natural Science Foundation of Beijing Municipality(No.Z180011)the Fundamental Research Funds for the Central Universities.
文摘Semiconducting transition-metal dichalcogenides(TMDs)have garnered significant interest due to their unique structures and properties,positioning them as promising candidates for novel electronic and optoelectronic devices.However,the performance of TMDs-based devices is hampered by the suboptimal quality of metal electrodes contacting the atomically thin TMDs layers.Understanding the mechanisms that influence contact quality is crucial for advancing TMDs devices.In this study,we investigated the conductive properties of tungsten selenide(WSe_(2))-based devices with different film thicknesses.Using the transmission line method,a negative correlation between contact resistance and film thickness in multi-electrode devices was revealed.Additionally,repeatability tests conducted at varied temperatures indicated enhanced device stability with increasing film thickness.Theoretical analysis,supported by thermionic emission theory and thermal simulations,suggests that the degradation in electrical properties is primarily due to the thermal effect at the contact interface.Furthermore,we found that van der Waals contacts could mitigate the thermal effect through a metal transfer method.Our findings elucidate the critical role of contact resistance in the electronic performance of 2D material-based field-effect transistors(FETs),which further expands their potential in the next generation of electronic and optoelectronic devices.
文摘Neutral oxygen evolution reaction(OER)is a crucial half-reaction for electrocatalytic chemical production under mild condition,but with limited development due to low activity and poor stability.Herein,a tungsten-doped cobalt molybdate(WDCMO)catalyst was synthesized for efficient and durable OER under neutral electrolyte.It is demonstrated that catalyst reconstruction is suppressed by W doping,which stabilizes the Co-O-Mo point-to-point connection in CoMoO_(4) architecture and stimulates to a lower valence state of active sites over the surface phase.Thereby,the surface structure maintains to avoid compound dissolution caused by over-oxidation during OER.Meanwhile,the WDCMO catalyst promotes charge transfer and optimizes*OH intermediate adsorption,which improves reaction kinetics and intrinsic activity.Consequently,the WDCMO electrode exhibits an overpotential of 302 mV at 10 mA cm^(-2) in neutral electrolyte with an improvement of 182 mV compared with CoMoO4 electrode.Furthermore,W doping significantly improves the electrode stability from 50 h to more than 320 h,with a suppressive potential attenuation from 2.82 to 0.29 mV h^(-1).This work will shed new light on designing rational electrocatalysts for neutral OER.
基金funded by the National Key Research&Development Program of China(No.2021YFC2900100)the Guangxi Natural Science Foundation(No.2022GXNSFFA035025)+3 种基金the Chinese National Natural Science Foundation(No.42372099)the China Geological Survey(No.DD20190379)the Science&Technology Fundamental Resources Investigation Program(No.2022FY101800)the Major Talent Program of Guangxi Zhuang Autonomous Region,and the Innovation Project of Guangxi Graduate Education(No.YCSW2023345)。
文摘Quartz vein-type tungsten deposits are a common W deposit type.Their ore vein distribution was previously considered to be controlled by regional horizontal tectonic stress.In this paper,14 tungsten deposits with fan-shaped mineralization in SE China are summarized,and the relations between their ore veins and granite and the ore-forming structural stress field are analyzed.These deposits have a post-magmatic hydrothermal genesis and involve the formation of two sets of veins with similar strike and opposite dips at the top of the ore-causative granite bodies,forming a vertical fan-shaped profile.Their ore veins were coeval with the underlying granite bodies,and generally extend along the long axis of the granite.In such fan-shaped ore formation,the stress is highly focused at the top of the granite and gradually weakens outward.The maximum principal stress(σ1)is perpendicular to the granite contact surface,and radiates outward from the pluton.Meanwhile,the minimum principal stress(σ3)forms an arc-shaped band parallel to the contact surface.Our findings,together with published numerical modeling indicate that the emplacement dynamics of granitic magma(rather than regional horizontal tectonic stress)are essential controls on the distribution of ore veins in quartz vein-type tungsten deposits.
基金supported by the National Natural Science Foundation of China(Grant Nos.52001037,U2037601,and U21A2048)the Science and Technology Program of Guangzhou,China(Grant No.2022BLC003).
文摘Si-containing Mg alloys solidified at conventional rates often contain coarse and sharp Mg_(2)Si phases,which can result in inferior material properties.In this study,Mg-6wt.%Si(Mg-6Si)alloy was prepared by wire arc additive manufacturing(WAAM),employing the gas tungsten arc welding technique with rapid cooling.The microstructures and mechanical properties of the WAAM alloy were investigated and compared with those of the as-cast samples produced using a metal mold.The results indicate that the WAAM Mg-6Si is harder and stronger than the as-cast samples.The microhardness of the WAAM Mg-6Si increases by 36.6% in comparison to that of as-cast Mg-6Si alloy.Furthermore,the average tensile strengths at room temperature and 150℃ increases by 63.4% and 21.3%,respectively.WAAM refines both the Mg_(2)Si phase and the overall grains,resulting in a homogeneous morphology and improved mechanical properties.The granular Mg_(2)Si phase,characterized by fine particles with a diffused distribution,shows a significant increase in concentration.The acicular Mg_(2)Si phase is distributed along the grain boundaries,and its concentration significantly decreases.The average grain size of the Mg_(2)Si phase is about 9.20μm,about 5 times smaller.The refinement and distribution of the granular Mg_(2)Si phase,as well as the reduction in the amount of needle-like Mg_(2)Si particles,are the key factors for improving the mechanical properties of WAAM Mg-6Si alloy.
基金supported by the National Natural Science Foundation of China(No.12375314)。
文摘Tungsten is considered the most promising plasma-facing material for fusion reactors with exceptional performance.Under certain conditions,activated tungsten dust can be generated through plasma–wall interactions and released into the atmosphere.Activated tungsten migrates downward in the soil after atmospheric deposition.However,effective methods for evaluating the environmental dose of gamma rays emitted by activated tungsten are still lacking.Consequently,a method for evaluating the air-absorbed dose rate of activated tungsten dust was proposed considering soil attenuation.Key parameters including the mass attenuation coefficient and energy absorption build-up factor were determined for the main gamma ray energies of radionuclides within the activated tungsten dust.Additionally,air-absorbed dose rates were calculated by assuming that radioactive sources were located at different soil depths and radii.It was found that a soil depth of 50 cm significantly attenuated the environmental dose by 99.9%,whereas the air-absorbed dose rates within the horizontal distance of 500 cm accounted for 91%of the total dose rate.Therefore,this study underscored the importance of soil attenuation in environmental dose assessments,which must be carefully re-examined for the safety analysis of fusion reactors.
