Protonic solid oxide electrolysis cells(P-SOECs)are a promising technology for water electrolysis to produce green hydrogen.However,there are still challenges related key materials and anode/electrolyte interface.P-SO...Protonic solid oxide electrolysis cells(P-SOECs)are a promising technology for water electrolysis to produce green hydrogen.However,there are still challenges related key materials and anode/electrolyte interface.P-SOECs with Zr-rich electrolyte,called Zr-rich side P-SOECs,possess high thermodynamically stability under high steam concentrations but the large reaction resistances and the current leakage,thus the inferior performances.In this study,an efficient functional interlayer Ba_(0.95)La_(0.05)Fe_(0.8)Zn_(0.2)O_(3-δ)(BLFZ)in-between the anode and the electrolyte is developed.The electrochemical performances of P-SOECs are greatly enhanced because the BLFZ can greatly increase the interface contact,boost anode reaction kinetics,and increase proton injection into electrolyte.As a result,the P-SOEC yields high current density of 0.83 A cm^(-2) at 600℃ in 1.3 Vamong all the reported Zr-rich side cells.This work not only offers an efficient functional interlayer for P-SOECs but also holds the potential to achieve P-SOECs with high performances and long-term stability.展开更多
Proton-conducting materials have attracted considerable interest because of their extensive application in energy storage and conversion devices.Among them,metal-organic frameworks(MOFs)present tremendous development ...Proton-conducting materials have attracted considerable interest because of their extensive application in energy storage and conversion devices.Among them,metal-organic frameworks(MOFs)present tremendous development potential and possibilities for constructing novel advanced proton conductors due to their special advantages in crystallinity,designability,and porosity.In particular,several special design strategies for the structure of MOFs have opened new doors for the advancement of MOF proton conductors,such as charged network construction,ligand functionalization,metal-center manipulation,defective engineering,guest molecule incorporation,and pore-space manipulation.With the implementation of these strategies,proton-conducting MOFs have developed significantly and profoundly within the last decade.Therefore,in this review,we critically discuss and analyze the fundamental principles,design strategies,and implementation methods targeted at improving the proton conductivity of MOFs through representative examples.Besides,the structural features,the proton conduction mechanism and the behavior of MOFs are discussed thoroughly and meticulously.Future endeavors are also proposed to address the challenges of proton-conducting MOFs in practical research.We sincerely expect that this review will bring guidance and inspiration for the design of proton-conducting MOFs and further motivate the research enthusiasm for novel proton-conducting materials.展开更多
The transition of hydrogen sourcing from carbon-intensive to water-based methodologies is underway,with renewable energy-powered proton exchange membrane water electrolysis(PEMWE)emerging as the preeminent pathway for...The transition of hydrogen sourcing from carbon-intensive to water-based methodologies is underway,with renewable energy-powered proton exchange membrane water electrolysis(PEMWE)emerging as the preeminent pathway for hydrogen production.Despite remarkable advancements in this field,confronting the sluggish electrochemical kinetics and inherent high-energy consumption arising from deteriorated mass transport within PEMWE systems remains a formidable obstacle.This impediment stems primarily from the hindered protons mass transfer and the untimely hydrogen bubbles detachment.To address these challenges,we harness the inherent variability of electrical energy and introduce an innovative pulsed dynamic water electrolysis system.Compared to constant voltage electrolysis(hydrogen production rate:51.6 m L h^(-1),energy consumption:5.37 kWh Nm-^(3)H_(2)),this strategy(hydrogen production rate:66 m L h^(-1),energy consumption:3.83 kWh Nm-^(3)H_(2))increases the hydrogen production rate by approximately 27%and reduces the energy consumption by about 28%.Furthermore,we demonstrate the practicality of this system by integrating it with an off-grid photovoltaic(PV)system designed for outdoor operation,successfully driving a hydrogen production current of up to 500 mA under an average voltage of approximately 2 V.The combined results of in-situ characterization and finite element analysis reveal the performance enhancement mechanism:pulsed dynamic electrolysis(PDE)dramatically accelerates the enrichment of protons at the electrode/solution interface and facilitates the release of bubbles on the electrode surface.As such,PDE-enhanced PEMWE represents a synergistic advancement,concurrently enhancing both the hydrogen generation reaction and associated transport processes.This promising technology not only redefines the landscape of electrolysis-based hydrogen production but also holds immense potential for broadening its application across a diverse spectrum of electrocatalytic endeavors.展开更多
PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula...PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula for Pr BSCF is AA'B_(2)O_(5+δ), with Pr(A-site) and Ba/Sr(A'-site) alternately stacked along the c-axis. Due to these structural features, the bulk oxygen ion diffusivity is significantly enhanced through the disorder-free channels in the PrO layer;thus, the A site cations(lanthanide ions) play a pivotal role in determining the overall electrochemical properties of layered perovskites. Consequently, previous research has predominantly focused on the electrical properties and oxygen bulk/surface kinetics of Ln cation effects,whereas the hydration properties for PCFC systems remain unidentified. Here, we thoroughly examined the proton uptake behavior and thermodynamic parameters for the hydration reaction to conclusively determine the changes in the electrochemical performances depending on LnBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(LnBSCF,Ln=Pr, Nd, and Gd) cathodes. At 500 ℃, the quantitative proton concentration of PrBSCF was 2.04 mol% and progressively decreased as the Ln cation size decreased. Similarly, the Gibbs free energy indicated that less energy was required for the formation of protonic defects in the order of Pr BSCF < Nd BSCF < Gd BSCF. To elucidate the close relationship between hydration properties and electrochemical performances in LnBSCF cathodes, PCFC single cell measurements and analysis of the distribution of relaxation time were further investigated.展开更多
Reversible protonic ceramic cells(RePCCs)hold promise for efficient energy storage,but their practicality is hindered by a lack of high-performance air electrode materials.Ruddlesden-Popper perovskite Sr_(3)Fe_(2)O_(7...Reversible protonic ceramic cells(RePCCs)hold promise for efficient energy storage,but their practicality is hindered by a lack of high-performance air electrode materials.Ruddlesden-Popper perovskite Sr_(3)Fe_(2)O_(7−δ)(SF)exhibits superior proton uptake and rapid ionic conduction,boosting activity.However,excessive proton uptake during RePCC operation degrades SF’s crystal structure,impacting durability.This study introduces a novel A/B-sites co-substitution strategy for modifying air electrodes,incorporating Sr-deficiency and Nb-substitution to create Sr_(2.8)Fe_(1.8)Nb_(0.2)O_(7−δ)(D-SFN).Nb stabilizes SF’s crystal,curbing excessive phase formation,and Sr-deficiency boosts oxygen vacancy concentration,optimizing oxygen transport.The D-SFN electrode demonstrates outstanding activity and durability,achieving a peak power density of 596 mW cm^(−2)in fuel cell mode and a current density of−1.19 A cm^(−2)in electrolysis mode at 1.3 V,650℃,with excellent cycling durability.This approach holds the potential for advancing robust and efficient air electrodes in RePCCs for renewable energy storage.展开更多
The poor electrochemical performance of all-solid-state batteries(ASSBs),which is assemblied by Ni-rich cathode and poly(ethylene oxide)(PEO)-based electrolytes,can be attributed to unstable cathodic interface and poo...The poor electrochemical performance of all-solid-state batteries(ASSBs),which is assemblied by Ni-rich cathode and poly(ethylene oxide)(PEO)-based electrolytes,can be attributed to unstable cathodic interface and poor crystal structure stability of Ni-rich cathode.Several coating strategies are previously employed to enhance the stability of the cathodic interface and crystal structure for Ni-rich cathode.However,these methods can hardly achieve simplicity and high efficiency simultaneously.In this work,polyacrylic acid(PAA)replaced traditional PVDF as a binder for cathode,which can achieve a uniform PAA-Li(LixPAA(0<x≤1))coating layer on the surface of single-crystal LiNi_(0.83)Co_(0.12)Mn_(0.05)O_(2)(SC-NCM83)due to H^(+)/Li^(+)exchange reaction during the initial charging-discharging process.The formation of PAA-Li coating layer on cathode can promote interfacial Li^(+)transport and enhance the stability of the cathodic interface.Furthermore,the partially-protonated surface of SC-NCM83 casued by H^(+)/Li^(+)exchange reaction can restrict Ni ions transport to enhance the crystal structure stability.The proposed SC-NCM83-PAA exhibits superior cycling performance with a retention of 92%compared with that(57.3%)of SC-NCM83-polyvinylidene difluoride(PVDF)after 200 cycles.This work provides a practical strategy to construct high-performance cathodes for ASSBs.展开更多
Radio frequency quadrupoles(RFQs),which are crucial components of proton injectors,significantly affect the performance of proton accelerator facilities.An RFQ with a high frequency of 714 MHz dedicated to compact pro...Radio frequency quadrupoles(RFQs),which are crucial components of proton injectors,significantly affect the performance of proton accelerator facilities.An RFQ with a high frequency of 714 MHz dedicated to compact proton injectors for medi-cal applications is designed in this study.The RFQ is designed to accelerate proton beams from 50 keV to 4 MeV within a short length of 2 m and can be matched closely with the downstream drift tube linac to capture more particles through a preliminary optimization.To develop an advanced RFQ,challenging techniques,including fabrication and tuning method,must be evaluated and verified using a prototype.An aluminium prototype is derived from the conceptual design of the RFQ and then redesigned to confirm the radio frequency performance,fabrication procedure,and feasibility of the tuning algorithm.Eventually,a new tuning algorithm based on the response matrix and least-squares method is developed,which yields favorable results based on the prototype,i.e.,the errors of the dipole and quadrupole components reduced to a low level after several tuning iterations.Benefiting from the conceptual design and techniques obtained from the prototype,the formal mechanical design of the 2-m RFQ is ready for the next manufacturing step.展开更多
Industrial water splitting has long been suppressed by the sluggish kinetics of the oxygen evolution reaction(OER),which requires a catalyst to be efficient.Herein,we propose a molecular-level proton acceptor strategy...Industrial water splitting has long been suppressed by the sluggish kinetics of the oxygen evolution reaction(OER),which requires a catalyst to be efficient.Herein,we propose a molecular-level proton acceptor strategy to produce an efficient OER catalyst that can boost industrial-scale water splitting.Molecular-level phosphate(-PO_(4))group is introduced to modify the surface of PrBa_(0.5)Ca_(0.5)Co_(2)O_(5)+δ(PBCC).The achieved catalyst(PO_(4)-PBCC)exhibits significantly enhanced catalytic performance in alkaline media.Based on the X-ray absorption spectroscopy results and density functional theory(DFT)calculations,the PO_(4)on the surface,which is regarded as the Lewis base,is the key factor to overcome the kinetic limitation of the proton transfer process during the OER.The use of the catalyst in a membrane electrode assembly(MEA)is further evaluated for industrial-scale water splitting,and it only needs a low voltage of 1.66 V to achieve a large current density of 1 A cm^(-2).This work provides a new molecular-level strategy to develop highly efficient OER electrocatalysts for industrial applications.展开更多
Aqueous proton batteries(APBs) offer a viable and attractive option in the field of affordable and sustainable energy solutions.Organic polymers are highly favored due to their environmentally friendly manufacturabili...Aqueous proton batteries(APBs) offer a viable and attractive option in the field of affordable and sustainable energy solutions.Organic polymers are highly favored due to their environmentally friendly manufacturability and malleable molecular configurations,making them suitable materials for constructing APB electrodes.Nonetheless,their currently limited capacity for proton-associated redox reactions poses a challenge to the widespread usage.Herein,we have developed a highly redox-active organic polymer(PTA) tailored for APB applications.The inclusion of dual redox-active moieties in the extended nconjugated frameworks not only enhances the redox activity and refines the electronic properties,but also ensures the high structural integrity of the PTA polymer.When used as an electrode,the PTA polymer has a notable ability to store protons,with a large capacity of 213.99 mA h g^(-1) at 1 A g^(-1) and exceptional long-term stability,as evidenced by retaining 94.6% of its initial capacity after 20,000 cycles.In situ techniques alongside theoretical calculations have unveiled efficient redox processes occurring at C=N and C=O redox-active sites within the PTA electrode upon proton uptake/removal.Furthermore,a softpackage APB device has been assembled with impressive electrochemical behaviors and excellent operational lifespan,accentuating its significant promise for real-world deployment.展开更多
Cone-beam computed tomography(CBCT) is mostly used for position verification during the treatment process. However,severe image artifacts in CBCT hinder its direct use in dose calculation and adaptive radiation therap...Cone-beam computed tomography(CBCT) is mostly used for position verification during the treatment process. However,severe image artifacts in CBCT hinder its direct use in dose calculation and adaptive radiation therapy re-planning for proton therapy. In this study, an improved U-Net neural network named CBAM-U-Net was proposed for CBCT noise reduction in proton therapy, which is a CBCT denoised U-Net network with convolutional block attention modules. The datasets contained 20 groups of head and neck images. The CT images were registered to CBCT images as ground truth. The original CBCT denoised U-Net network, sCTU-Net, was trained for model performance comparison. The synthetic CT(SCT) images generated by CBAM-U-Net and the original sCTU-Net are called CBAM-SCT and U-Net-SCT images, respectively. The HU accuracies of the CT, CBCT, and SCT images were compared using four metrics: mean absolute error(MAE), root mean square error(RMSE), peak signal-to-noise ratio(PSNR), and structure similarity index measure(SSIM). The mean values of the MAE, RMSE, PSNR, and SSIM of CBAM-SCT images were 23.80 HU, 64.63 HU, 52.27 dB, and 0.9919, respectively,which were superior to those of the U-Net-SCT images. To evaluate dosimetric accuracy, the range accuracy was compared for a single-energy proton beam. The γ-index pass rates of a 4 cm × 4 cm scanned field and simple plan were calculated to compare the effects of the noise reduction capabilities of the original U-Net and CBAM-U-Net on the dose calculation results. CBAM-U-Net reduced noise more effectively than sCTU-Net, particularly in high-density tissues. We proposed a CBAM-U-Net model for CBCT noise reduction in proton therapy. Owing to the excellent noise reduction capabilities of CBAM-U-Net, the proposed model provided relatively explicit information regarding patient tissues. Moreover, it maybe be used in dose calculation and adaptive treatment planning in the future.展开更多
Moisture-enabled electricity(ME)is a method of converting the potential energy of water in the external environment into electrical energy through the interaction of functional materials with water molecules and can b...Moisture-enabled electricity(ME)is a method of converting the potential energy of water in the external environment into electrical energy through the interaction of functional materials with water molecules and can be directly applied to energy harvesting and signal expression.However,ME can be unreliable in numerous applications due to its sluggish response to moisture,thus sacrificing the value of fast energy harvesting and highly accurate information representation.Here,by constructing a moisture-electric-moisture-sensitive(ME-MS)heterostructure,we develop an efficient ME generator with ultra-fast electric response to moisture achieved by triggering Grotthuss protons hopping in the sensitized ZnO,which modulates the heterostructure built-in interfacial potential,enables quick response(0.435 s),an unprecedented ultra-fast response rate of 972.4 mV s^(−1),and a durable electrical signal output for 8 h without any attenuation.Our research provides an efficient way to generate electricity and important insight for a deeper understanding of the mechanisms of moisture-generated carrier migration in ME generator,which has a more comprehensive working scene and can serve as a typical model for human health monitoring and smart medical electronics design.展开更多
The utilization of a proton beam from the China Spallation Neutron Source(CSNS)for producing medical radioisotopes is appealing owing to its high current intensity and high energy.The medical isotope production based ...The utilization of a proton beam from the China Spallation Neutron Source(CSNS)for producing medical radioisotopes is appealing owing to its high current intensity and high energy.The medical isotope production based on the proton beam at the CSNS is significant for the development of future radiopharmaceuticals,particularly for theα-emitting radiopharmaceu-ticals.The production yield and activity of typical medical isotopes were estimated using the FLUKA simulation.The results indicate that the 300-MeV proton beam with a power of 100 kW at CSNS-II is highly suitable for proof-of-principle studies of most medical radioisotopes.In particular,this proton beam offers tremendous advantages for the large-scale production of alpha radioisotopes,such as 225Ac,whose theoretical production yield can reach approximately 57 Ci/week.Based on these results,we provide perspectives on the use of CSNS proton beams to produce radioisotopes for medical applications.展开更多
Rhodopsin is a seven-helical transmembrane protein with a retinal chromophore covalently bound to a conserved lysine in helix G via a retinal protonated Schiff base(RPSB).Microbial rhodopsins absorb light through chro...Rhodopsin is a seven-helical transmembrane protein with a retinal chromophore covalently bound to a conserved lysine in helix G via a retinal protonated Schiff base(RPSB).Microbial rhodopsins absorb light through chromophore and play a fundamental role in optogenetics.Numerous microbial rhodopsins have been discovered,contributing to diverse functions and colors.Solid-state NMR spectroscopy has been instrumental in elucidating the conformation of chromophores and the three-dimensional structure of microbial rhodopsins.This review focuses on the 15N chemical shift values of RPSB and summarizes recent progress in the field.We displayed the correlation between the 15N isotropic chemical shift values of RPSB and the maximum absorption wavelength of rhodopsin using solid-state NMR spectroscopy.展开更多
The application of superconducting(SC)technology enables magnets to excite strong fields with small footprints,which has great potential for miniaturizing proton therapy gantries.However,the slow ramping rate of SC ma...The application of superconducting(SC)technology enables magnets to excite strong fields with small footprints,which has great potential for miniaturizing proton therapy gantries.However,the slow ramping rate of SC magnets results in a low treatment efficiency compared with normal-conducting(NC)gantries.To address this problem,this study proposes a compact proton therapy gantry design with a large momentum acceptance utilizing alternating-gradient canted-cosine-theta(AG-CCT)SC magnets.In our design,a high-transmission degrader is mounted in the middle of the gantry,and the upstream beamline employs NC magnets with small apertures.Downstream of the degrader,large-bore AG-CCT magnets with strong alternating focusing gradients are set symmetrically as a local achromat,which realizes a momentum acceptance of 20%(or 40%in the energy domain).Therefore,only three magnetic working points are required to cover a treatment energy of 70-230 Me V.Owing to the large momentum acceptance,the proton beam after the degrader can be directly delivered to the isocenter without truncating its energy spectrum,which can significantly increase the treatment efficiency but causes severe dispersion effects during pencil beam scanning.Therefore,a compensation method was introduced by tuning the normal and skewed quadrupoles during the scanning process.As a result,the new gantry not only presents a remarkable reduction in the size and weight of the facility but also shows good potential for fast treatment.展开更多
High-performance proton exchange membranes are of great importance for fuel cells.Here,we have synthesized polycarboxylate plasticizer modified MIL-101-Cr-NH_(2)(PCP-MCN),a kind of hybrid metal-organic framework,which ...High-performance proton exchange membranes are of great importance for fuel cells.Here,we have synthesized polycarboxylate plasticizer modified MIL-101-Cr-NH_(2)(PCP-MCN),a kind of hybrid metal-organic framework,which exhibits a superior proton conductivity.PCP-MCN nanoparticles are used as additives to fabricate PCP-MCN/Nafion composite membranes.Microstructures and characteristics of PCP-MCN and these membranes have been extensively investigated.Significant enhancement in proton conduction for PCP-MCN around 55℃ is interestingly found due to the thermal motion of the PCP molecular chains.Robust mechanical properties and higher thermal decomposition temperature of the composite membranes are directly ascribed to strong intermolecular interactions between PCP-MCN and Nafion side chains,i.e.,the formation of substantial acid–base pairs(-SO_(3)^(-)…^(+)H–NH-),which further improves compatibility between additive and Nafion matrix.At the same humidity and temperature condition,the water uptake of composite membranes significantly increases due to the incorporation of porous additives with abundant functional groups and thus less crystallinity degree in comparison to pristine Nafion.Proton conductivity(σ)over wide ranges of humidities(30-100%RH at 25℃)and temperatures(30-98℃ at 100%RH)for prepared membranes is measured.The s in PCPMCN/Nafion composite membranes is remarkably enhanced,i.e.0.245 S/cm for PCP-MCN-3wt.%/Nafion is twice that of Nafion membrane at 98℃ and 100%RH,because of the establishment of well-interconnected proton transport ionic water channels and perhaps faster protonation–deprotonation processes.The composite membranes possess weak humidity-dependence of proton transport and higher water uptake due to excellent water retention ability of PCP-MCN.In particular,when 3 wt.%PCP-MCN was added to Nafion,the power density of a single-cell fabricated with this composite membrane reaches impressively 0.480,1.098 W/cm^(2) under 40%RH,100%RH at 60℃,respectively,guaranteeing it to be a promising proton exchange membrane.展开更多
The single event effect(SEE) sensitivity of silicon–germanium heterojunction bipolar transistor(Si Ge HBT) irradiated by 100-Me V proton is investigated. The simulation results indicate that the most sensitive positi...The single event effect(SEE) sensitivity of silicon–germanium heterojunction bipolar transistor(Si Ge HBT) irradiated by 100-Me V proton is investigated. The simulation results indicate that the most sensitive position of the Si Ge HBT device is the emitter center, where the protons pass through the larger collector-substrate(CS) junction. Furthermore, in this work the experimental studies are also carried out by using 100-Me V proton. In order to consider the influence of temperature on SEE, both simulation and experiment are conducted at a temperature of 93 K. At a cryogenic temperature, the carrier mobility increases, which leads to higher transient current peaks, but the duration of the current decreases significantly.Notably, at the same proton flux, there is only one single event transient(SET) that occurs at 93 K. Thus, the radiation hard ability of the device increases at cryogenic temperatures. The simulation results are found to be qualitatively consistent with the experimental results of 100-Me V protons. To further evaluate the tolerance of the device, the influence of proton on Si Ge HBT after gamma-ray(^(60)Coγ) irradiation is investigated. As a result, as the cumulative dose increases, the introduction of traps results in a significant reduction in both the peak value and duration of the transient currents.展开更多
Boron neutron capture therapy(BNCT)is recognized as a precise binary targeted radiotherapy technique that effectively eliminates tumors through the^(10)B(n,α)^(7)Li nuclear reaction.Among various neutron sources,acce...Boron neutron capture therapy(BNCT)is recognized as a precise binary targeted radiotherapy technique that effectively eliminates tumors through the^(10)B(n,α)^(7)Li nuclear reaction.Among various neutron sources,accelerator-based sources have emerged as particularly promising for BNCT applications.The^(7)Li(p,n)^(7)Be reaction is highly regarded as a potential neutron source for BNCT,owing to its low threshold energy for the reaction,significant neutron yield,appropriate average neutron energy,and additional benefits.This study utilized Monte Carlo simulations to model the physical interactions within a lithium target subjected to proton bombardment,including neutron moderation by an MgF_(2)moderator and subsequent BNCT dose analysis using a Snyder head phantom.The study focused on calculating the yields of epithermal neutrons for various incident proton energies,finding an optimal energy at 2.7 MeV.Furthermore,the Snyder head phantom was employed in dose simulations to validate the effectiveness of this specific incident energy when utilizing a^(7)Li(p,n)^(7)Be neutron source for BNCT purposes.展开更多
As an advanced treatment method in the past five years,ultra-high dose rate(FLASH)radiotherapy as a breakthrough and milestone in radiotherapy development has been verified to be much less harmful to healthy tissues i...As an advanced treatment method in the past five years,ultra-high dose rate(FLASH)radiotherapy as a breakthrough and milestone in radiotherapy development has been verified to be much less harmful to healthy tissues in different experiments.FLASH treatments require an instantaneous dose rate as high as hundreds of grays per second to complete the treatment in less than 100 ms.Current proton therapy facilities with the spread-out of the Bragg peak formed by different energy layers,to our knowledge,cannot easily achieve an adequate dose rate for FLASH treatments because the energy layer switch or gantry rotation of current facilities requires a few seconds,which is relatively long.A new design for a therapy facility based on a proton linear accelerator(linac)for FLASH treatment is proposed herein.It is designed under two criteria:no mechanical motion and no magnetic field variation.The new therapy facility can achieve an ultrahigh dose rate of up to 300 Gy/s;however,it delivers an instantaneous dose of 30 Gy within 100 ms to complete a typical FLASH treatment.The design includes a compact proton linac with permanent magnets,a fast beam kicker in both azimuth and elevation angles,a fixed gantry with a static superconducting coil to steer proton bunches with all energy,a fast beam scanner using radio-frequency(RF)deflectors,and a fast low-level RF system.All relevant principles and conceptual proposals are presented herein.展开更多
Silica nanosheets(SN)derived from natural vermiculite(Verm)were successfully incorporated into polyethersulfone-polyvinylpyrrolidone(PES-PVP)polymer to fabricate high-temperature proton exchange membranes(HT-PEMs).The...Silica nanosheets(SN)derived from natural vermiculite(Verm)were successfully incorporated into polyethersulfone-polyvinylpyrrolidone(PES-PVP)polymer to fabricate high-temperature proton exchange membranes(HT-PEMs).The content of SN filler was varied(0.1-0.75 wt%)to study its influence on proton conductivity,power density and durability.Benefiting from the hydroxyl groups of SN that enable the formation of additional proton-transferring pathways,the inorganic-organic membrane displayed enhanced proton conductivity of 48.2 mS/cm and power density of 495 mW/cm^(2) at 150℃ without humidification when the content of SN is 0.25 wt%.Furthermore,exfoliated SN(E-SN)and sulfonated SN(S-SN),which were fabricated by a liquid-phase exfoliation method and silane condensation,respectively,were embedded in PES-PVP polymer matrix by a simple blending method.Due to the significant contribution from sulfonic groups in S-SN,the membrane with 0.25 wt%S-SN reached the highest proton conductivity of51.5 mS/cm and peak power density of 546 mW/cm^(2) at150℃,48%higher than the pristine PES-PVP membranes.Compared to unaltered PES-PVP membrane,SN added hybrid composite membrane demonstrated excellent durability for the fuel cell at 150℃.Using a facile method to prepare 2D SN from natural clay minerals,the strategy of exfoliation and functionalization of SN can be potentially used in the production of HT-PEMs.展开更多
Proton exchange membranes （PEMs） are a key material for proton exchange membrane fuel cells （PEM-FCs）, Non-fluorinated hydrocarbon PEMs are low-cost alternatives to Nation, but limited by the low pro-ton conductiv...Proton exchange membranes （PEMs） are a key material for proton exchange membrane fuel cells （PEM-FCs）, Non-fluorinated hydrocarbon PEMs are low-cost alternatives to Nation, but limited by the low pro-ton conductivity, because of the weak phase segregation structure and narrow ion-transport channels.Various efforts have been taken to improve the performance of hydrocarbon PEMs, but mostly with com-plex methodologies. Here we demonstrate a simple, yet very efficient method to create phase segrega-tion structure inside a typical hydrocarbon PEM, sulfonated poly（ether ether ketone） （SPEEK）. By sim-ply adding appropriate amounts of water into the DMF solvent, the resulting SPEEK membrane exhibitswidened ion-transport channels, with the phase size of 2.7 nm, as indicated by both molecular dynamic（MD） simulations and transmission electron microscope （TEM） observations, and the proton conductivityis thus improved by 200%. These findings not only further our fundamental understanding of hydrocarbonPEMs, but are also valuable to the development of low-cost and practical fuel cell technologies.展开更多
基金financial support from the JSPS KAKENHI Grant-in-Aid for Scientific Research(B),No.21H02035KAKENHI Grant-in-Aid for Challenging Research(Exploratory),No.21K19017+2 种基金KAKENHI Grant-in-Aid for Transformative Research Areas(B),No.21H05100National Natural Science Foundation of China,No.22409033 and No.22409035Basic and Applied Basic Research Foundation of Guangdong Province,No.2022A1515110470.
文摘Protonic solid oxide electrolysis cells(P-SOECs)are a promising technology for water electrolysis to produce green hydrogen.However,there are still challenges related key materials and anode/electrolyte interface.P-SOECs with Zr-rich electrolyte,called Zr-rich side P-SOECs,possess high thermodynamically stability under high steam concentrations but the large reaction resistances and the current leakage,thus the inferior performances.In this study,an efficient functional interlayer Ba_(0.95)La_(0.05)Fe_(0.8)Zn_(0.2)O_(3-δ)(BLFZ)in-between the anode and the electrolyte is developed.The electrochemical performances of P-SOECs are greatly enhanced because the BLFZ can greatly increase the interface contact,boost anode reaction kinetics,and increase proton injection into electrolyte.As a result,the P-SOEC yields high current density of 0.83 A cm^(-2) at 600℃ in 1.3 Vamong all the reported Zr-rich side cells.This work not only offers an efficient functional interlayer for P-SOECs but also holds the potential to achieve P-SOECs with high performances and long-term stability.
基金supported by the China Scholarship Council(No.202408120105)National Natural Science Foundation of China(32301530)+5 种基金Young Elite Scientist Sponsorship Program by CAST(No.YESS20230242)Tianjin Excellent Special Commissioner for Agricultural Science and Technology Project(23ZYCGSN00580)Natural Science Foundation of Tianjin(23JCZDJC00630)China Postdoctoral Science Foundation(2023M740563)State Key Laboratory of Pulp and Paper Engineering(202412,202413)the Central Publicinterest Scientific Institution Basa Research Fund(No.Y2022QC30).
文摘Proton-conducting materials have attracted considerable interest because of their extensive application in energy storage and conversion devices.Among them,metal-organic frameworks(MOFs)present tremendous development potential and possibilities for constructing novel advanced proton conductors due to their special advantages in crystallinity,designability,and porosity.In particular,several special design strategies for the structure of MOFs have opened new doors for the advancement of MOF proton conductors,such as charged network construction,ligand functionalization,metal-center manipulation,defective engineering,guest molecule incorporation,and pore-space manipulation.With the implementation of these strategies,proton-conducting MOFs have developed significantly and profoundly within the last decade.Therefore,in this review,we critically discuss and analyze the fundamental principles,design strategies,and implementation methods targeted at improving the proton conductivity of MOFs through representative examples.Besides,the structural features,the proton conduction mechanism and the behavior of MOFs are discussed thoroughly and meticulously.Future endeavors are also proposed to address the challenges of proton-conducting MOFs in practical research.We sincerely expect that this review will bring guidance and inspiration for the design of proton-conducting MOFs and further motivate the research enthusiasm for novel proton-conducting materials.
基金National Natural Science Foundation of China(No.52476192,No.52106237)Natural Science Foundation of Heilongjiang Province(No.YQ2022E027)。
文摘The transition of hydrogen sourcing from carbon-intensive to water-based methodologies is underway,with renewable energy-powered proton exchange membrane water electrolysis(PEMWE)emerging as the preeminent pathway for hydrogen production.Despite remarkable advancements in this field,confronting the sluggish electrochemical kinetics and inherent high-energy consumption arising from deteriorated mass transport within PEMWE systems remains a formidable obstacle.This impediment stems primarily from the hindered protons mass transfer and the untimely hydrogen bubbles detachment.To address these challenges,we harness the inherent variability of electrical energy and introduce an innovative pulsed dynamic water electrolysis system.Compared to constant voltage electrolysis(hydrogen production rate:51.6 m L h^(-1),energy consumption:5.37 kWh Nm-^(3)H_(2)),this strategy(hydrogen production rate:66 m L h^(-1),energy consumption:3.83 kWh Nm-^(3)H_(2))increases the hydrogen production rate by approximately 27%and reduces the energy consumption by about 28%.Furthermore,we demonstrate the practicality of this system by integrating it with an off-grid photovoltaic(PV)system designed for outdoor operation,successfully driving a hydrogen production current of up to 500 mA under an average voltage of approximately 2 V.The combined results of in-situ characterization and finite element analysis reveal the performance enhancement mechanism:pulsed dynamic electrolysis(PDE)dramatically accelerates the enrichment of protons at the electrode/solution interface and facilitates the release of bubbles on the electrode surface.As such,PDE-enhanced PEMWE represents a synergistic advancement,concurrently enhancing both the hydrogen generation reaction and associated transport processes.This promising technology not only redefines the landscape of electrolysis-based hydrogen production but also holds immense potential for broadening its application across a diverse spectrum of electrocatalytic endeavors.
基金supported by the National Research Foundation (NRF) grant funded by the Korea government (NRF2022R1C1C1007619, NRF-2021M3H4A1A01002921, NRF2021M3I3A1084292)supported by the KIST Institutional Program (Project No. 2E32592-23-069)。
文摘PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula for Pr BSCF is AA'B_(2)O_(5+δ), with Pr(A-site) and Ba/Sr(A'-site) alternately stacked along the c-axis. Due to these structural features, the bulk oxygen ion diffusivity is significantly enhanced through the disorder-free channels in the PrO layer;thus, the A site cations(lanthanide ions) play a pivotal role in determining the overall electrochemical properties of layered perovskites. Consequently, previous research has predominantly focused on the electrical properties and oxygen bulk/surface kinetics of Ln cation effects,whereas the hydration properties for PCFC systems remain unidentified. Here, we thoroughly examined the proton uptake behavior and thermodynamic parameters for the hydration reaction to conclusively determine the changes in the electrochemical performances depending on LnBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(LnBSCF,Ln=Pr, Nd, and Gd) cathodes. At 500 ℃, the quantitative proton concentration of PrBSCF was 2.04 mol% and progressively decreased as the Ln cation size decreased. Similarly, the Gibbs free energy indicated that less energy was required for the formation of protonic defects in the order of Pr BSCF < Nd BSCF < Gd BSCF. To elucidate the close relationship between hydration properties and electrochemical performances in LnBSCF cathodes, PCFC single cell measurements and analysis of the distribution of relaxation time were further investigated.
基金supported by the Research Grants Council,University Grants Committee,Hong Kong SAR(Project Number:N_PolyU552/20)supported by the National Nature Science Foundation of China(22209138)Guangdong Basic and Applied Basic Research Foundation(2021A1515110464).
文摘Reversible protonic ceramic cells(RePCCs)hold promise for efficient energy storage,but their practicality is hindered by a lack of high-performance air electrode materials.Ruddlesden-Popper perovskite Sr_(3)Fe_(2)O_(7−δ)(SF)exhibits superior proton uptake and rapid ionic conduction,boosting activity.However,excessive proton uptake during RePCC operation degrades SF’s crystal structure,impacting durability.This study introduces a novel A/B-sites co-substitution strategy for modifying air electrodes,incorporating Sr-deficiency and Nb-substitution to create Sr_(2.8)Fe_(1.8)Nb_(0.2)O_(7−δ)(D-SFN).Nb stabilizes SF’s crystal,curbing excessive phase formation,and Sr-deficiency boosts oxygen vacancy concentration,optimizing oxygen transport.The D-SFN electrode demonstrates outstanding activity and durability,achieving a peak power density of 596 mW cm^(−2)in fuel cell mode and a current density of−1.19 A cm^(−2)in electrolysis mode at 1.3 V,650℃,with excellent cycling durability.This approach holds the potential for advancing robust and efficient air electrodes in RePCCs for renewable energy storage.
基金the financial support from the National Natural Science Foundation of China(Nos.52034011 and 52204328)the Science and Technology Innovation Program of Hunan Province(2023RC305)the Changsha Municipal Natural Science Foundation(kq2202085)。
文摘The poor electrochemical performance of all-solid-state batteries(ASSBs),which is assemblied by Ni-rich cathode and poly(ethylene oxide)(PEO)-based electrolytes,can be attributed to unstable cathodic interface and poor crystal structure stability of Ni-rich cathode.Several coating strategies are previously employed to enhance the stability of the cathodic interface and crystal structure for Ni-rich cathode.However,these methods can hardly achieve simplicity and high efficiency simultaneously.In this work,polyacrylic acid(PAA)replaced traditional PVDF as a binder for cathode,which can achieve a uniform PAA-Li(LixPAA(0<x≤1))coating layer on the surface of single-crystal LiNi_(0.83)Co_(0.12)Mn_(0.05)O_(2)(SC-NCM83)due to H^(+)/Li^(+)exchange reaction during the initial charging-discharging process.The formation of PAA-Li coating layer on cathode can promote interfacial Li^(+)transport and enhance the stability of the cathodic interface.Furthermore,the partially-protonated surface of SC-NCM83 casued by H^(+)/Li^(+)exchange reaction can restrict Ni ions transport to enhance the crystal structure stability.The proposed SC-NCM83-PAA exhibits superior cycling performance with a retention of 92%compared with that(57.3%)of SC-NCM83-polyvinylidene difluoride(PVDF)after 200 cycles.This work provides a practical strategy to construct high-performance cathodes for ASSBs.
基金This work was supported by National Natural Science Foundation of China(No.12222513).
文摘Radio frequency quadrupoles(RFQs),which are crucial components of proton injectors,significantly affect the performance of proton accelerator facilities.An RFQ with a high frequency of 714 MHz dedicated to compact proton injectors for medi-cal applications is designed in this study.The RFQ is designed to accelerate proton beams from 50 keV to 4 MeV within a short length of 2 m and can be matched closely with the downstream drift tube linac to capture more particles through a preliminary optimization.To develop an advanced RFQ,challenging techniques,including fabrication and tuning method,must be evaluated and verified using a prototype.An aluminium prototype is derived from the conceptual design of the RFQ and then redesigned to confirm the radio frequency performance,fabrication procedure,and feasibility of the tuning algorithm.Eventually,a new tuning algorithm based on the response matrix and least-squares method is developed,which yields favorable results based on the prototype,i.e.,the errors of the dipole and quadrupole components reduced to a low level after several tuning iterations.Benefiting from the conceptual design and techniques obtained from the prototype,the formal mechanical design of the 2-m RFQ is ready for the next manufacturing step.
基金supported by the National Natural Sci-ence Foundation of China(22272081),Jiangsu Provincial Specially Appointed Professors Foundation.
文摘Industrial water splitting has long been suppressed by the sluggish kinetics of the oxygen evolution reaction(OER),which requires a catalyst to be efficient.Herein,we propose a molecular-level proton acceptor strategy to produce an efficient OER catalyst that can boost industrial-scale water splitting.Molecular-level phosphate(-PO_(4))group is introduced to modify the surface of PrBa_(0.5)Ca_(0.5)Co_(2)O_(5)+δ(PBCC).The achieved catalyst(PO_(4)-PBCC)exhibits significantly enhanced catalytic performance in alkaline media.Based on the X-ray absorption spectroscopy results and density functional theory(DFT)calculations,the PO_(4)on the surface,which is regarded as the Lewis base,is the key factor to overcome the kinetic limitation of the proton transfer process during the OER.The use of the catalyst in a membrane electrode assembly(MEA)is further evaluated for industrial-scale water splitting,and it only needs a low voltage of 1.66 V to achieve a large current density of 1 A cm^(-2).This work provides a new molecular-level strategy to develop highly efficient OER electrocatalysts for industrial applications.
基金China Postdoctoral Science Foundation (2022M711686)Joint Project of Industry-University-Research of Jiangsu Province (BY20230490)。
文摘Aqueous proton batteries(APBs) offer a viable and attractive option in the field of affordable and sustainable energy solutions.Organic polymers are highly favored due to their environmentally friendly manufacturability and malleable molecular configurations,making them suitable materials for constructing APB electrodes.Nonetheless,their currently limited capacity for proton-associated redox reactions poses a challenge to the widespread usage.Herein,we have developed a highly redox-active organic polymer(PTA) tailored for APB applications.The inclusion of dual redox-active moieties in the extended nconjugated frameworks not only enhances the redox activity and refines the electronic properties,but also ensures the high structural integrity of the PTA polymer.When used as an electrode,the PTA polymer has a notable ability to store protons,with a large capacity of 213.99 mA h g^(-1) at 1 A g^(-1) and exceptional long-term stability,as evidenced by retaining 94.6% of its initial capacity after 20,000 cycles.In situ techniques alongside theoretical calculations have unveiled efficient redox processes occurring at C=N and C=O redox-active sites within the PTA electrode upon proton uptake/removal.Furthermore,a softpackage APB device has been assembled with impressive electrochemical behaviors and excellent operational lifespan,accentuating its significant promise for real-world deployment.
基金Digital Medical Equipment Research and Development Project,Ministry of Science and Technology,China:The development of Synchrotron-based proton therapy system(2016YFC0105400).
文摘Cone-beam computed tomography(CBCT) is mostly used for position verification during the treatment process. However,severe image artifacts in CBCT hinder its direct use in dose calculation and adaptive radiation therapy re-planning for proton therapy. In this study, an improved U-Net neural network named CBAM-U-Net was proposed for CBCT noise reduction in proton therapy, which is a CBCT denoised U-Net network with convolutional block attention modules. The datasets contained 20 groups of head and neck images. The CT images were registered to CBCT images as ground truth. The original CBCT denoised U-Net network, sCTU-Net, was trained for model performance comparison. The synthetic CT(SCT) images generated by CBAM-U-Net and the original sCTU-Net are called CBAM-SCT and U-Net-SCT images, respectively. The HU accuracies of the CT, CBCT, and SCT images were compared using four metrics: mean absolute error(MAE), root mean square error(RMSE), peak signal-to-noise ratio(PSNR), and structure similarity index measure(SSIM). The mean values of the MAE, RMSE, PSNR, and SSIM of CBAM-SCT images were 23.80 HU, 64.63 HU, 52.27 dB, and 0.9919, respectively,which were superior to those of the U-Net-SCT images. To evaluate dosimetric accuracy, the range accuracy was compared for a single-energy proton beam. The γ-index pass rates of a 4 cm × 4 cm scanned field and simple plan were calculated to compare the effects of the noise reduction capabilities of the original U-Net and CBAM-U-Net on the dose calculation results. CBAM-U-Net reduced noise more effectively than sCTU-Net, particularly in high-density tissues. We proposed a CBAM-U-Net model for CBCT noise reduction in proton therapy. Owing to the excellent noise reduction capabilities of CBAM-U-Net, the proposed model provided relatively explicit information regarding patient tissues. Moreover, it maybe be used in dose calculation and adaptive treatment planning in the future.
基金the Natural Science Foundation of Beijing Municipality(2222075)National Natural Science Foundation of China(22279010,21671020,51673026)Analysis&Testing Center,Beijing Institute of Technology.
文摘Moisture-enabled electricity(ME)is a method of converting the potential energy of water in the external environment into electrical energy through the interaction of functional materials with water molecules and can be directly applied to energy harvesting and signal expression.However,ME can be unreliable in numerous applications due to its sluggish response to moisture,thus sacrificing the value of fast energy harvesting and highly accurate information representation.Here,by constructing a moisture-electric-moisture-sensitive(ME-MS)heterostructure,we develop an efficient ME generator with ultra-fast electric response to moisture achieved by triggering Grotthuss protons hopping in the sensitized ZnO,which modulates the heterostructure built-in interfacial potential,enables quick response(0.435 s),an unprecedented ultra-fast response rate of 972.4 mV s^(−1),and a durable electrical signal output for 8 h without any attenuation.Our research provides an efficient way to generate electricity and important insight for a deeper understanding of the mechanisms of moisture-generated carrier migration in ME generator,which has a more comprehensive working scene and can serve as a typical model for human health monitoring and smart medical electronics design.
基金the National Natural Science Foundation of China(No.12075135)the China Postdoctoral Science Foundation(No.2022M721908).
文摘The utilization of a proton beam from the China Spallation Neutron Source(CSNS)for producing medical radioisotopes is appealing owing to its high current intensity and high energy.The medical isotope production based on the proton beam at the CSNS is significant for the development of future radiopharmaceuticals,particularly for theα-emitting radiopharmaceu-ticals.The production yield and activity of typical medical isotopes were estimated using the FLUKA simulation.The results indicate that the 300-MeV proton beam with a power of 100 kW at CSNS-II is highly suitable for proof-of-principle studies of most medical radioisotopes.In particular,this proton beam offers tremendous advantages for the large-scale production of alpha radioisotopes,such as 225Ac,whose theoretical production yield can reach approximately 57 Ci/week.Based on these results,we provide perspectives on the use of CSNS proton beams to produce radioisotopes for medical applications.
基金supported in part by JSPS KAKENHI Grant Numbers in Japan(JP21H05229 to I.K.)JST CREST(JPMJCR21B2)The authors also thank Nobuko Yamaguchi for the financial support.
文摘Rhodopsin is a seven-helical transmembrane protein with a retinal chromophore covalently bound to a conserved lysine in helix G via a retinal protonated Schiff base(RPSB).Microbial rhodopsins absorb light through chromophore and play a fundamental role in optogenetics.Numerous microbial rhodopsins have been discovered,contributing to diverse functions and colors.Solid-state NMR spectroscopy has been instrumental in elucidating the conformation of chromophores and the three-dimensional structure of microbial rhodopsins.This review focuses on the 15N chemical shift values of RPSB and summarizes recent progress in the field.We displayed the correlation between the 15N isotropic chemical shift values of RPSB and the maximum absorption wavelength of rhodopsin using solid-state NMR spectroscopy.
基金supported by the National Natural Science Foundation of China(No.11975107,12205111)。
文摘The application of superconducting(SC)technology enables magnets to excite strong fields with small footprints,which has great potential for miniaturizing proton therapy gantries.However,the slow ramping rate of SC magnets results in a low treatment efficiency compared with normal-conducting(NC)gantries.To address this problem,this study proposes a compact proton therapy gantry design with a large momentum acceptance utilizing alternating-gradient canted-cosine-theta(AG-CCT)SC magnets.In our design,a high-transmission degrader is mounted in the middle of the gantry,and the upstream beamline employs NC magnets with small apertures.Downstream of the degrader,large-bore AG-CCT magnets with strong alternating focusing gradients are set symmetrically as a local achromat,which realizes a momentum acceptance of 20%(or 40%in the energy domain).Therefore,only three magnetic working points are required to cover a treatment energy of 70-230 Me V.Owing to the large momentum acceptance,the proton beam after the degrader can be directly delivered to the isocenter without truncating its energy spectrum,which can significantly increase the treatment efficiency but causes severe dispersion effects during pencil beam scanning.Therefore,a compensation method was introduced by tuning the normal and skewed quadrupoles during the scanning process.As a result,the new gantry not only presents a remarkable reduction in the size and weight of the facility but also shows good potential for fast treatment.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.12075172,12375288,12205089,and 12105048)National Key R&D Program of China(Grant No.2019YFA0210003)Guangdong Basic and Applied Basic Research Foundation(No.2020A1515110817).
文摘High-performance proton exchange membranes are of great importance for fuel cells.Here,we have synthesized polycarboxylate plasticizer modified MIL-101-Cr-NH_(2)(PCP-MCN),a kind of hybrid metal-organic framework,which exhibits a superior proton conductivity.PCP-MCN nanoparticles are used as additives to fabricate PCP-MCN/Nafion composite membranes.Microstructures and characteristics of PCP-MCN and these membranes have been extensively investigated.Significant enhancement in proton conduction for PCP-MCN around 55℃ is interestingly found due to the thermal motion of the PCP molecular chains.Robust mechanical properties and higher thermal decomposition temperature of the composite membranes are directly ascribed to strong intermolecular interactions between PCP-MCN and Nafion side chains,i.e.,the formation of substantial acid–base pairs(-SO_(3)^(-)…^(+)H–NH-),which further improves compatibility between additive and Nafion matrix.At the same humidity and temperature condition,the water uptake of composite membranes significantly increases due to the incorporation of porous additives with abundant functional groups and thus less crystallinity degree in comparison to pristine Nafion.Proton conductivity(σ)over wide ranges of humidities(30-100%RH at 25℃)and temperatures(30-98℃ at 100%RH)for prepared membranes is measured.The s in PCPMCN/Nafion composite membranes is remarkably enhanced,i.e.0.245 S/cm for PCP-MCN-3wt.%/Nafion is twice that of Nafion membrane at 98℃ and 100%RH,because of the establishment of well-interconnected proton transport ionic water channels and perhaps faster protonation–deprotonation processes.The composite membranes possess weak humidity-dependence of proton transport and higher water uptake due to excellent water retention ability of PCP-MCN.In particular,when 3 wt.%PCP-MCN was added to Nafion,the power density of a single-cell fabricated with this composite membrane reaches impressively 0.480,1.098 W/cm^(2) under 40%RH,100%RH at 60℃,respectively,guaranteeing it to be a promising proton exchange membrane.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.61574171,61704127,11875229,51872251,and 12027813)。
文摘The single event effect(SEE) sensitivity of silicon–germanium heterojunction bipolar transistor(Si Ge HBT) irradiated by 100-Me V proton is investigated. The simulation results indicate that the most sensitive position of the Si Ge HBT device is the emitter center, where the protons pass through the larger collector-substrate(CS) junction. Furthermore, in this work the experimental studies are also carried out by using 100-Me V proton. In order to consider the influence of temperature on SEE, both simulation and experiment are conducted at a temperature of 93 K. At a cryogenic temperature, the carrier mobility increases, which leads to higher transient current peaks, but the duration of the current decreases significantly.Notably, at the same proton flux, there is only one single event transient(SET) that occurs at 93 K. Thus, the radiation hard ability of the device increases at cryogenic temperatures. The simulation results are found to be qualitatively consistent with the experimental results of 100-Me V protons. To further evaluate the tolerance of the device, the influence of proton on Si Ge HBT after gamma-ray(^(60)Coγ) irradiation is investigated. As a result, as the cumulative dose increases, the introduction of traps results in a significant reduction in both the peak value and duration of the transient currents.
文摘Boron neutron capture therapy(BNCT)is recognized as a precise binary targeted radiotherapy technique that effectively eliminates tumors through the^(10)B(n,α)^(7)Li nuclear reaction.Among various neutron sources,accelerator-based sources have emerged as particularly promising for BNCT applications.The^(7)Li(p,n)^(7)Be reaction is highly regarded as a potential neutron source for BNCT,owing to its low threshold energy for the reaction,significant neutron yield,appropriate average neutron energy,and additional benefits.This study utilized Monte Carlo simulations to model the physical interactions within a lithium target subjected to proton bombardment,including neutron moderation by an MgF_(2)moderator and subsequent BNCT dose analysis using a Snyder head phantom.The study focused on calculating the yields of epithermal neutrons for various incident proton energies,finding an optimal energy at 2.7 MeV.Furthermore,the Snyder head phantom was employed in dose simulations to validate the effectiveness of this specific incident energy when utilizing a^(7)Li(p,n)^(7)Be neutron source for BNCT purposes.
基金This work was supported by the Alliance of International Science Organizations(No.ANSO-CR-KP-2020-16)the National Key R&D Program of China(No.2018YFF0109203).
文摘As an advanced treatment method in the past five years,ultra-high dose rate(FLASH)radiotherapy as a breakthrough and milestone in radiotherapy development has been verified to be much less harmful to healthy tissues in different experiments.FLASH treatments require an instantaneous dose rate as high as hundreds of grays per second to complete the treatment in less than 100 ms.Current proton therapy facilities with the spread-out of the Bragg peak formed by different energy layers,to our knowledge,cannot easily achieve an adequate dose rate for FLASH treatments because the energy layer switch or gantry rotation of current facilities requires a few seconds,which is relatively long.A new design for a therapy facility based on a proton linear accelerator(linac)for FLASH treatment is proposed herein.It is designed under two criteria:no mechanical motion and no magnetic field variation.The new therapy facility can achieve an ultrahigh dose rate of up to 300 Gy/s;however,it delivers an instantaneous dose of 30 Gy within 100 ms to complete a typical FLASH treatment.The design includes a compact proton linac with permanent magnets,a fast beam kicker in both azimuth and elevation angles,a fixed gantry with a static superconducting coil to steer proton bunches with all energy,a fast beam scanner using radio-frequency(RF)deflectors,and a fast low-level RF system.All relevant principles and conceptual proposals are presented herein.
基金the EPSRC grant EP/009050/1supported by the Henry Royce Institute for Advanced Materials which is funded by EPSRC grants EP/S019367/1,EP/P025021/1,EP/R00661X/1 and EP/P025498/1.
文摘Silica nanosheets(SN)derived from natural vermiculite(Verm)were successfully incorporated into polyethersulfone-polyvinylpyrrolidone(PES-PVP)polymer to fabricate high-temperature proton exchange membranes(HT-PEMs).The content of SN filler was varied(0.1-0.75 wt%)to study its influence on proton conductivity,power density and durability.Benefiting from the hydroxyl groups of SN that enable the formation of additional proton-transferring pathways,the inorganic-organic membrane displayed enhanced proton conductivity of 48.2 mS/cm and power density of 495 mW/cm^(2) at 150℃ without humidification when the content of SN is 0.25 wt%.Furthermore,exfoliated SN(E-SN)and sulfonated SN(S-SN),which were fabricated by a liquid-phase exfoliation method and silane condensation,respectively,were embedded in PES-PVP polymer matrix by a simple blending method.Due to the significant contribution from sulfonic groups in S-SN,the membrane with 0.25 wt%S-SN reached the highest proton conductivity of51.5 mS/cm and peak power density of 546 mW/cm^(2) at150℃,48%higher than the pristine PES-PVP membranes.Compared to unaltered PES-PVP membrane,SN added hybrid composite membrane demonstrated excellent durability for the fuel cell at 150℃.Using a facile method to prepare 2D SN from natural clay minerals,the strategy of exfoliation and functionalization of SN can be potentially used in the production of HT-PEMs.
基金financially supported by the National Key Research and Development Program of China (2016YFB0101203)the National Natural Science Foundation of China (91545205,21633008)
文摘Proton exchange membranes （PEMs） are a key material for proton exchange membrane fuel cells （PEM-FCs）, Non-fluorinated hydrocarbon PEMs are low-cost alternatives to Nation, but limited by the low pro-ton conductivity, because of the weak phase segregation structure and narrow ion-transport channels.Various efforts have been taken to improve the performance of hydrocarbon PEMs, but mostly with com-plex methodologies. Here we demonstrate a simple, yet very efficient method to create phase segrega-tion structure inside a typical hydrocarbon PEM, sulfonated poly（ether ether ketone） （SPEEK）. By sim-ply adding appropriate amounts of water into the DMF solvent, the resulting SPEEK membrane exhibitswidened ion-transport channels, with the phase size of 2.7 nm, as indicated by both molecular dynamic（MD） simulations and transmission electron microscope （TEM） observations, and the proton conductivityis thus improved by 200%. These findings not only further our fundamental understanding of hydrocarbonPEMs, but are also valuable to the development of low-cost and practical fuel cell technologies.
