目的:探讨影响大型语言模型(large language models,LLMs)生成乳腺MRI报告性能的关键因素,并确定一种成本效益高的部署策略,以提升其在规模化影像诊断中的应用。方法:本研究回顾性整合三家医疗机构的中文放射报告,构建数据集。通过微调...目的:探讨影响大型语言模型(large language models,LLMs)生成乳腺MRI报告性能的关键因素,并确定一种成本效益高的部署策略,以提升其在规模化影像诊断中的应用。方法:本研究回顾性整合三家医疗机构的中文放射报告,构建数据集。通过微调多种LLMs(包括ChatGPT、Llama3、Qwen2.5、DeepSeek-R1-Distill-Llama3_8B),评估模型架构、参数规模及预训练数据对性能的影响。采用BLEU、ROUGE、Cosine Similarity及BERTScore评价生成诊断的文本质量,并通过BI-RADS分类任务评估其诊断推理能力。结果:实验表明,增加训练数据可显著提升Llama3_8B模型的性能:BLEU值从1.69×10^(-3)升至0.78,ROUGE-L从0.05升至0.90,BERTScore从0.52升至0.94,Cosine Similarity从0.04升至0.88。不同架构、推理能力及参数规模的模型在诊断准确率上差异较小(66%~67%)。模型在外部验证集的性能较内部验证集下降明显(如Llama3_8B的BERTScore从0.94降至0.71,准确率从66%降至22%)。报告分析显示,模型报告在完整度(4.56 vs.4.46)和正确性(4.33 vs.4.15)上优于人工报告。结论:经微调的LLMs在乳腺MRI印象生成任务中表现出色。本研究为模型微调提供了实践指导,为医疗机构提供可定制化的低成本部署方案,从而提升诊断效率并减轻放射科医师工作负荷。展开更多
Light has been clinically utilized as a stimulation in medical treatment,such as Low-level laser therapy and photodynamic thenapy,which has been more and more widely accepted in public.The penetration depth of the tre...Light has been clinically utilized as a stimulation in medical treatment,such as Low-level laser therapy and photodynamic thenapy,which has been more and more widely accepted in public.The penetration depth of the treatment light is important for precision treatment and safety control.The isue of light penetration has been highlighted in biomedical optics field for decades.However,quantitative research is sparse and even there are conflicts of view on the capability of near-infrared light penet ration into brain tissue.This study attempts to quantitatively revisit this issue by innovative high-realistic 3D Monte Caro modeling of stimulated light penetnation within high precision Visible Chinese human head.The properties of light,such as its wave-length,ilumination profle and size are concern in this study.We made stra ightforward and quantitative comparisons among the ffects by the light properties(i.e.,wavelengths:660,810 and 980 nn;beam types:Gaussi an and flat beamn;bear dianeters:0,2,4 and 6 cm)which are in the range of light treatment.The findings include about 3%of light dosage within brain tisue;the combination of Gaussian beam and 810nm light make the max imum light penetration(>5cm),which allows light to cross through gray matter into white mater.This study offered us,the first time as we know,quantitative guide for light stimulation parameter optimization in medical treatment.展开更多
Limited information exists about the effects of antioxidants on sperm motility and DNA integrity during vitrification in humans. This study compared the effects of reduced glutathione (GSH) and monothioglycerol (MTG) ...Limited information exists about the effects of antioxidants on sperm motility and DNA integrity during vitrification in humans. This study compared the effects of reduced glutathione (GSH) and monothioglycerol (MTG) at different concentrations on post-thaw sperm motility and DNA integrity after vitrification in humans using 0.25 M trehalose as a cryoprotective agent, and found that supplementation of MTG or GSH at 0.5 mM resulted in significantly higher (P < 0.05) recovery rates of post-thaw total and progressive motilities. GSH was more powerful than MTG at the same concentration in cryoprotecting sperm motility (38.9% ± 3.6% vs 32.8% ± 2.4% compared to the control 26.8% ± 2.1% in recovery rate of progressive motility), but both had no significant influence on sperm DNA integrity during vitrification. It was concluded that sperm motility is more sensitive to oxidative stress during vitrification than sperm nuclear DNA, and supplementation of MTG or GSH in vitrification medium is beneficial in cryoprotecting sperm motility.展开更多
Spaceborne Synthetic Aperture Radar(SAR) is a well-established and powerful imaging technology that can provide high-resolution images of the Earth’s surface on a global scale. For future SAR systems, one of the key ...Spaceborne Synthetic Aperture Radar(SAR) is a well-established and powerful imaging technology that can provide high-resolution images of the Earth’s surface on a global scale. For future SAR systems, one of the key capabilities is to acquire images with both high-resolution and wide-swath. In parallel to the evolution of SAR sensors, more precise range models, and effective imaging algorithms are required. Due to the significant azimuth-variance of the echo signal in High-Resolution Wide-Swath(HRWS) SAR, two challenges have been faced in conventional imaging algorithms. The first challenge is constructing a precise range model of the whole scene and the second one is to develop an effective imaging algorithm since existing ones fail to process highresolution and wide azimuth swath SAR data effectively. In this paper, an Advanced High-order Nonlinear Chirp Scaling(A-HNLCS) algorithm for HRWS SAR is proposed. First, a novel Second-Order Equivalent Squint Range Model(SOESRM) is developed to describe the range history of the whole scene, by introducing a quadratic curve to fit the deviation of the azimuth FM rate. Second, a corresponding algorithm is derived, where the azimuth-variance of the echo signal is solved by azimuth equalizing processing and accurate focusing is achieved through a high-order nonlinear chirp scaling algorithm. As a result, the whole scene can be accurately focused through one single imaging processing. Simulations are provided to validate the proposed range model and imaging algorithm.展开更多
Rapid freezing and vitrification are becoming popular for human sperm cryopreservation;however, it remains unclear which method is better. The aims of the present study were to determine the optimal trehalose concentr...Rapid freezing and vitrification are becoming popular for human sperm cryopreservation;however, it remains unclear which method is better. The aims of the present study were to determine the optimal trehalose concentration and to compare the cryoprotective effects of rapid freezing and vitrification. The results showed that: 1) The optimal trehalose concentration was 0.25 mol/L;2) The post-thaw recovery rates of total and progressive sperm motilities after rapid freezing (38.6% ± 3.0% and 41.1% ± 5.0%) were significantly higher (P 0.05) than that after vitrification (26.1% ± 3.1% and 27.2% ± 1.3%) when 0.5 mL straws were used;3) However, the recovery rates of total and progressive motilities after rapid freezing in 0.5 mL straw (26.7% ± 9.6% and 26.8% ± 8.7%) were significantly lower (P 0.05) than that after vitrification in a novel straw-in-straw system (43.1% ± 4.2% and 41.8% ± 15.5%);and 4) The post-thaw sperm nuclear DNA damage level after rapid freezing in 0.5 mL straw (8.7% ± 2.8%) was not significantly different from that of sperm after vitrification in the straw-in-straw system (9.2% ± 2.5%). It was concluded that rapid freezing is superior to vitrification when using 0.5 mL straws;however, vitrification is superior to rapid freezing when using the straw-in-straw systems.展开更多
Molecular dynamics simulations demand an unprecedented combination of accuracy and scalability to tackle grand challenges in catalysis and materials design.To bridge this gap,we present AlphaNet,a local-frame-based eq...Molecular dynamics simulations demand an unprecedented combination of accuracy and scalability to tackle grand challenges in catalysis and materials design.To bridge this gap,we present AlphaNet,a local-frame-based equivariant model that simultaneously improves computational efficiency and predictive precision for interatomic interactions.By constructing equivariant local frames with learnable geometric transitions and enabling contractions through spatial domain and temporal domain,AlphaNet enhances the representational capacity of atomic environments,achieving stateof-the-art accuracy in energy and force predictions.Extensive benchmarks on large-scale datasets spanningmolecular reactions,crystal stability,and surface catalysis(Matbench Discovery and OC2M)demonstrate its superior performance over existing neural network interatomic potentials while ensuring scalability across diverse system sizes with varying types of interatomic interactions.The synergy of accuracy,efficiency,and transferability positions AlphaNet as a transformative tool for modeling multiscale phenomena,decoding dynamics in catalysis and functional interfaces,with direct implications for accelerating the discovery of complex molecular systems and functional materials.Our code and data are available at https://github.com/zmyybc/AlphaNet.展开更多
The development of low-cost and efficient electrocatalysts for oxygen evolution reaction(OER)in acid electro-lytes is critical to the widespread implementation of proton electrolyte membrane water electrolyzers(PEMWE)...The development of low-cost and efficient electrocatalysts for oxygen evolution reaction(OER)in acid electro-lytes is critical to the widespread implementation of proton electrolyte membrane water electrolyzers(PEMWE)towards carbon neutralization.Noble metal Ir-and Ru-based materials are state-of-the-art catalysts but still suffer from prohibitive price and scarcity.In this context,a variety of noble metal-free catalysts have been developed to decrease the cost of PEMWE.In this review,we first summarize the activity expression mechanism and stability issues for non-precious metal catalysts,highlighting the origins of performance degradation and the possible mitigation strategies.Then,we systematically review several recently developed noble metal-free catalysts,focusing on the design rationale and the structure-performance relation.Finally,the development prospects of non-noble metal catalysts are prospected,with the potential challenges for practical applications presented.展开更多
Fe–N–C is hailed as the most promising candidate for replacing costly platinum-based catalysts for proton-exchange membrane fuel cells(PEMFCs)owing to their impressive catalytic activity and low cost.However;the dur...Fe–N–C is hailed as the most promising candidate for replacing costly platinum-based catalysts for proton-exchange membrane fuel cells(PEMFCs)owing to their impressive catalytic activity and low cost.However;the durability of Fe–N–C catalysts remains a major challenge;primarily due to an insufficient understanding of their degradation mechanisms.In this study;we monitor the real-time changes in the electrode during the oxygen reduction reaction(ORR);shedding light on the potentialdependent degradation mechanisms inherent to Fe–N–C catalysts.Utilizing in-situ differential electrochemical mass spectroscopy;we identify three distinct potential regions with varying degrees of performance loss;notably observing carbon corrosion signals at low potentials.Theoretical calculations and fluorescence probe experiments corroborate that degradation mechanisms at high potentials are primarily driven by strong oxidative potentials that overcome the carbon oxidation energy barrier;whereas the degradation at low potentials is predominantly caused by the high concentrations of reactive oxygen species(ROS)generated during the ORR.The potential-dependent carbon corrosion consequently leads to a similar dependence of demetallation of active sites on the working potential.This study offers a comprehensive understanding of the intrinsic interrelations among various degradation mechanisms;thus paving the way for enhancing the durability of Fe–N–C catalysts in PEMFC applications.展开更多
In this article, we propose a parameter vertex method to determine the upper and lower bounds of the dynamic response of structures with interval parameters, which can be regarded as an extension of the matrix vertex ...In this article, we propose a parameter vertex method to determine the upper and lower bounds of the dynamic response of structures with interval parameters, which can be regarded as an extension of the matrix vertex method proposed by Qiu and Wang. The matrix vertex method requires considerable computation time and encounters the dependency problem in practice,thereby limiting its application in engineering. The proposed parameter vertex method can avoid the dependency problem, and the number of possible vertex combinations in the proposed method is significantly less than that in the matrix vertex method.The parameter vertex method requires that each matrix element in the dynamic differential equation is monotonic with respect to the uncertain parameter, and that the dynamic response reaches its extreme value when the uncertain parameter is at its endpoint.To further reduce the runtime, both vertical and transversal parallel algorithms are introduced and integrated into the parameter vertex method to improve its computational efficiency. Two numerical examples are presented to demonstrate the proposed method combined with both parallel algorithms. The performances of the two parallel algorithms are thoroughly studied. The parameter vertex method combined with parallel algorithm can be used for large-scale computing.展开更多
The scale-up deployment of ruthenium(Ru)-based oxygen evolution reaction(OER)electrocatalysts in proton exchange membrane water electrolysis(PEMWE)is greatly restricted by the poor stability.As the lattice-oxygen-medi...The scale-up deployment of ruthenium(Ru)-based oxygen evolution reaction(OER)electrocatalysts in proton exchange membrane water electrolysis(PEMWE)is greatly restricted by the poor stability.As the lattice-oxygen-mediated mechanism(LOM)has been identified as the major contributor to the fast performance degradation,impeding lattice oxygen diffusion to inhibit lattice oxygen participation is imperative,yet remains challenging due to the lack of efficient approaches.Herein,we strategically regulate the bonding nature of Ru–O towards suppressed LOM via Ru-based high-entropy oxide(HEO)construction.The lattice disorder in HEOs is believed to increase migration energy barrier of lattice oxygen.As a result,the screened Ti_(23)Nb_(9)Hf_(13)W_(12)Ru_(43)O_(x) exhibits 11.7 times slower lattice oxygen diffusion rate,84%reduction in LOM ratio,and 29 times lifespan extension compared with the state-of-the-art RuO_(2) catalyst.Our work opens up a feasible avenue to constructing stabilized Ru-based OER catalysts towards scalable application.展开更多
In this study,Cinnamomum camphora seed kernel protein isolate(CPI)-dextran(DX)model system was used to investigate the impacts of reaction temperatures(70-100℃)and times(1-4 h)on the structure,functional properties a...In this study,Cinnamomum camphora seed kernel protein isolate(CPI)-dextran(DX)model system was used to investigate the impacts of reaction temperatures(70-100℃)and times(1-4 h)on the structure,functional properties and volatile compounds of Maillard reaction products(MRPs).The formation of MRPs was confirmed by SDS-PAGE,ultraviolet absorption and degree of glycation.Fourier transform infrared(FTIR)and circular dichroism(CD)spectroscopy showed that the secondary structure of MRPs tended to be more regular than native CPI.Moreover,MRPs had a lower free sulfhydryl group content and higher surface hydrophobicity than native CPI.Fluorescence spectra revealed that the tryptophan residues of CPI were transferred to a more hydrophobic microenvironment.The solubility and emulsifying stability of CPI were decreased,while the foaming activity,foaming stability,emulsion stability and apparent viscosity of CPI were significantly improved(p<0.05)after Maillard reaction.Furthermore,MRPs exhibited significantly improved(p<0.05)thermal stability and ABTS^(+)•radical scavenging activity than native CPI,while the DPPH+radical scavenging activity and ferric reducing power were decreased.In addition,volatile compounds,including aldehydes,ketones,benzenes and esters,were identified in MRPs.These results provide a theoretical guidance for future studies on CPI-DX conjugates.展开更多
Stable and efficient single atom catalysts(SACs)are highly desirable yet challenging in catalyzing acidic oxygen evolution reaction(OER).Herein,we report a novel iridium single atom catalyst structure,with atomic Ir d...Stable and efficient single atom catalysts(SACs)are highly desirable yet challenging in catalyzing acidic oxygen evolution reaction(OER).Herein,we report a novel iridium single atom catalyst structure,with atomic Ir doped in tetragonal PdO matrix(IrSAs-PdO)via a lattice-confined strategy.The optimized IrSAs-PdO-0.10 exhibited remarkable OER activity with an overpotential of 277 mV at 10 mA·cm^(-2) and long-term stability of 1000 h in 0.5 M H_(2)SO_(4).Furthermore,the turnover frequency attains 1.6 s^(-1) at an overpotential of 300 mV with a 24-fold increase in the intrinsic activity.The high activity originates from isolated iridium sites with low valence states and decreased Ir–O bonding covalency,and the excellent stability is a result of the effective confinement of iridium sites by Ir–O–Pd motifs.Moreover,we demonstrated for the first time that SACs have great potential in realizing ultralow loading of iridium(as low as microgram per square center meter level)in a practical water electrolyzer.展开更多
Masking is one of the most commonly used Side-Channel Attack （SCA） countermeasures and is built on a security framework, such as the ISW framework, and ensures theoretical security through secret sharing. Unfortunat...Masking is one of the most commonly used Side-Channel Attack （SCA） countermeasures and is built on a security framework, such as the ISW framework, and ensures theoretical security through secret sharing. Unfortunately, the theoretical security cannot guarantee practical security, because several possible weaknesses may exist in the actual implementation. These weaknesses likely come from the masking schemes or are introduced by the implementation methods. Finding the possible weakness of the masking scheme is an interesting and important issue for real applications. In this paper, the possible weaknesses for masking schemes in Field- Programmable Gate Array （FPGA） design are discussed. It was found that the combinational circuit is the key to the security of masking schemes. The Toggle Count （TC） method and its extension are utilized to evaluate the security of masking schemes in the design phase and the implementation phase separately. Comparing different logic-level simulators for the Xilinx FPGA platform, the behavioral and post-translate simulations are considered as the analysis method in the design phase, while the post-map and the post-route simulations are used to find the weakness during the implementation phase. Moreover, a Standard Delay Format （SDF） based improvement scheme is proposed to significantly increase the effectiveness of the TC model.展开更多
基金supports of the One University One Zone Growth Fund (No.A03013023001019)the Central University Basic Scientific Research Project Business Expenses (No.ZYGX2016J052)+1 种基金CAMS Innovation Fund for Medical Sciences (No.2016-I2M-3-023)National Natural Science Fund Projects (No.61675039).
文摘Light has been clinically utilized as a stimulation in medical treatment,such as Low-level laser therapy and photodynamic thenapy,which has been more and more widely accepted in public.The penetration depth of the treatment light is important for precision treatment and safety control.The isue of light penetration has been highlighted in biomedical optics field for decades.However,quantitative research is sparse and even there are conflicts of view on the capability of near-infrared light penet ration into brain tissue.This study attempts to quantitatively revisit this issue by innovative high-realistic 3D Monte Caro modeling of stimulated light penetnation within high precision Visible Chinese human head.The properties of light,such as its wave-length,ilumination profle and size are concern in this study.We made stra ightforward and quantitative comparisons among the ffects by the light properties(i.e.,wavelengths:660,810 and 980 nn;beam types:Gaussi an and flat beamn;bear dianeters:0,2,4 and 6 cm)which are in the range of light treatment.The findings include about 3%of light dosage within brain tisue;the combination of Gaussian beam and 810nm light make the max imum light penetration(>5cm),which allows light to cross through gray matter into white mater.This study offered us,the first time as we know,quantitative guide for light stimulation parameter optimization in medical treatment.
文摘Limited information exists about the effects of antioxidants on sperm motility and DNA integrity during vitrification in humans. This study compared the effects of reduced glutathione (GSH) and monothioglycerol (MTG) at different concentrations on post-thaw sperm motility and DNA integrity after vitrification in humans using 0.25 M trehalose as a cryoprotective agent, and found that supplementation of MTG or GSH at 0.5 mM resulted in significantly higher (P < 0.05) recovery rates of post-thaw total and progressive motilities. GSH was more powerful than MTG at the same concentration in cryoprotecting sperm motility (38.9% ± 3.6% vs 32.8% ± 2.4% compared to the control 26.8% ± 2.1% in recovery rate of progressive motility), but both had no significant influence on sperm DNA integrity during vitrification. It was concluded that sperm motility is more sensitive to oxidative stress during vitrification than sperm nuclear DNA, and supplementation of MTG or GSH in vitrification medium is beneficial in cryoprotecting sperm motility.
基金supported by the National Natural Science Foundation of China (No. 61861136008)。
文摘Spaceborne Synthetic Aperture Radar(SAR) is a well-established and powerful imaging technology that can provide high-resolution images of the Earth’s surface on a global scale. For future SAR systems, one of the key capabilities is to acquire images with both high-resolution and wide-swath. In parallel to the evolution of SAR sensors, more precise range models, and effective imaging algorithms are required. Due to the significant azimuth-variance of the echo signal in High-Resolution Wide-Swath(HRWS) SAR, two challenges have been faced in conventional imaging algorithms. The first challenge is constructing a precise range model of the whole scene and the second one is to develop an effective imaging algorithm since existing ones fail to process highresolution and wide azimuth swath SAR data effectively. In this paper, an Advanced High-order Nonlinear Chirp Scaling(A-HNLCS) algorithm for HRWS SAR is proposed. First, a novel Second-Order Equivalent Squint Range Model(SOESRM) is developed to describe the range history of the whole scene, by introducing a quadratic curve to fit the deviation of the azimuth FM rate. Second, a corresponding algorithm is derived, where the azimuth-variance of the echo signal is solved by azimuth equalizing processing and accurate focusing is achieved through a high-order nonlinear chirp scaling algorithm. As a result, the whole scene can be accurately focused through one single imaging processing. Simulations are provided to validate the proposed range model and imaging algorithm.
文摘Rapid freezing and vitrification are becoming popular for human sperm cryopreservation;however, it remains unclear which method is better. The aims of the present study were to determine the optimal trehalose concentration and to compare the cryoprotective effects of rapid freezing and vitrification. The results showed that: 1) The optimal trehalose concentration was 0.25 mol/L;2) The post-thaw recovery rates of total and progressive sperm motilities after rapid freezing (38.6% ± 3.0% and 41.1% ± 5.0%) were significantly higher (P 0.05) than that after vitrification (26.1% ± 3.1% and 27.2% ± 1.3%) when 0.5 mL straws were used;3) However, the recovery rates of total and progressive motilities after rapid freezing in 0.5 mL straw (26.7% ± 9.6% and 26.8% ± 8.7%) were significantly lower (P 0.05) than that after vitrification in a novel straw-in-straw system (43.1% ± 4.2% and 41.8% ± 15.5%);and 4) The post-thaw sperm nuclear DNA damage level after rapid freezing in 0.5 mL straw (8.7% ± 2.8%) was not significantly different from that of sperm after vitrification in the straw-in-straw system (9.2% ± 2.5%). It was concluded that rapid freezing is superior to vitrification when using 0.5 mL straws;however, vitrification is superior to rapid freezing when using the straw-in-straw systems.
基金supported by National Key Research and Development Project(2022YFA1503000)National Natural Science Foundation of China(No.92261111)+1 种基金the NSFC Center for Single-Atom Catalysis(No.22388102)We are also grateful to the Center of High-Performance Computing at Tsinghua University for providing computational resources.We also acknowledge the Welch Foundation(F-1841)for support.We thank Prof.Aditi Krishnapriyan for her insightful suggestions and valuable discussions.
文摘Molecular dynamics simulations demand an unprecedented combination of accuracy and scalability to tackle grand challenges in catalysis and materials design.To bridge this gap,we present AlphaNet,a local-frame-based equivariant model that simultaneously improves computational efficiency and predictive precision for interatomic interactions.By constructing equivariant local frames with learnable geometric transitions and enabling contractions through spatial domain and temporal domain,AlphaNet enhances the representational capacity of atomic environments,achieving stateof-the-art accuracy in energy and force predictions.Extensive benchmarks on large-scale datasets spanningmolecular reactions,crystal stability,and surface catalysis(Matbench Discovery and OC2M)demonstrate its superior performance over existing neural network interatomic potentials while ensuring scalability across diverse system sizes with varying types of interatomic interactions.The synergy of accuracy,efficiency,and transferability positions AlphaNet as a transformative tool for modeling multiscale phenomena,decoding dynamics in catalysis and functional interfaces,with direct implications for accelerating the discovery of complex molecular systems and functional materials.Our code and data are available at https://github.com/zmyybc/AlphaNet.
基金the National Key R&D Program of China(No.2021YFB4000200)the National Natural Science Foundation of China(No.22232004)+1 种基金the Instrument Developing Project of the Chinese Academy of Sciences,the Jilin Province Development and Reform Commission Program(2023C032-6)the Jilin Province Science and Technology Development Program(No.20210301008GX,YDZJ202202CXJD011,20210502002ZP)for financial support.
文摘The development of low-cost and efficient electrocatalysts for oxygen evolution reaction(OER)in acid electro-lytes is critical to the widespread implementation of proton electrolyte membrane water electrolyzers(PEMWE)towards carbon neutralization.Noble metal Ir-and Ru-based materials are state-of-the-art catalysts but still suffer from prohibitive price and scarcity.In this context,a variety of noble metal-free catalysts have been developed to decrease the cost of PEMWE.In this review,we first summarize the activity expression mechanism and stability issues for non-precious metal catalysts,highlighting the origins of performance degradation and the possible mitigation strategies.Then,we systematically review several recently developed noble metal-free catalysts,focusing on the design rationale and the structure-performance relation.Finally,the development prospects of non-noble metal catalysts are prospected,with the potential challenges for practical applications presented.
基金supported by the National Key R&D Program of China(2022YFB4004100)the National Natural Science Foundation of China(22272161,and 22179126)Jilin Province Science and Technology Development Program(20210502002ZP,YDZJ202202-CXJD011,and 20240101019JC).
文摘Fe–N–C is hailed as the most promising candidate for replacing costly platinum-based catalysts for proton-exchange membrane fuel cells(PEMFCs)owing to their impressive catalytic activity and low cost.However;the durability of Fe–N–C catalysts remains a major challenge;primarily due to an insufficient understanding of their degradation mechanisms.In this study;we monitor the real-time changes in the electrode during the oxygen reduction reaction(ORR);shedding light on the potentialdependent degradation mechanisms inherent to Fe–N–C catalysts.Utilizing in-situ differential electrochemical mass spectroscopy;we identify three distinct potential regions with varying degrees of performance loss;notably observing carbon corrosion signals at low potentials.Theoretical calculations and fluorescence probe experiments corroborate that degradation mechanisms at high potentials are primarily driven by strong oxidative potentials that overcome the carbon oxidation energy barrier;whereas the degradation at low potentials is predominantly caused by the high concentrations of reactive oxygen species(ROS)generated during the ORR.The potential-dependent carbon corrosion consequently leads to a similar dependence of demetallation of active sites on the working potential.This study offers a comprehensive understanding of the intrinsic interrelations among various degradation mechanisms;thus paving the way for enhancing the durability of Fe–N–C catalysts in PEMFC applications.
基金supported by the Defense Industrial Technology Development Program(Grant Nos.2016YFB0200700,JCKY2016601B001,and JCKY2016204B101)the Program of Introducing Talents of Discipline to Universities of China(111 Project)(Grant No.B07009)National Nature Science Foundation of China(Grant Nos.11372025,11432002,and11572024)
文摘In this article, we propose a parameter vertex method to determine the upper and lower bounds of the dynamic response of structures with interval parameters, which can be regarded as an extension of the matrix vertex method proposed by Qiu and Wang. The matrix vertex method requires considerable computation time and encounters the dependency problem in practice,thereby limiting its application in engineering. The proposed parameter vertex method can avoid the dependency problem, and the number of possible vertex combinations in the proposed method is significantly less than that in the matrix vertex method.The parameter vertex method requires that each matrix element in the dynamic differential equation is monotonic with respect to the uncertain parameter, and that the dynamic response reaches its extreme value when the uncertain parameter is at its endpoint.To further reduce the runtime, both vertical and transversal parallel algorithms are introduced and integrated into the parameter vertex method to improve its computational efficiency. Two numerical examples are presented to demonstrate the proposed method combined with both parallel algorithms. The performances of the two parallel algorithms are thoroughly studied. The parameter vertex method combined with parallel algorithm can be used for large-scale computing.
基金The authors thank the National Key R&D Program of China(No.2021YFB4000200)the National Natural Science Foundation of China(No.22232004)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA21090400)the Jilin Province Science and Technology Development Program(Nos.20210301008GX,YDZJ202202CXJD011,and 20210502002ZP)for financial support.
文摘The scale-up deployment of ruthenium(Ru)-based oxygen evolution reaction(OER)electrocatalysts in proton exchange membrane water electrolysis(PEMWE)is greatly restricted by the poor stability.As the lattice-oxygen-mediated mechanism(LOM)has been identified as the major contributor to the fast performance degradation,impeding lattice oxygen diffusion to inhibit lattice oxygen participation is imperative,yet remains challenging due to the lack of efficient approaches.Herein,we strategically regulate the bonding nature of Ru–O towards suppressed LOM via Ru-based high-entropy oxide(HEO)construction.The lattice disorder in HEOs is believed to increase migration energy barrier of lattice oxygen.As a result,the screened Ti_(23)Nb_(9)Hf_(13)W_(12)Ru_(43)O_(x) exhibits 11.7 times slower lattice oxygen diffusion rate,84%reduction in LOM ratio,and 29 times lifespan extension compared with the state-of-the-art RuO_(2) catalyst.Our work opens up a feasible avenue to constructing stabilized Ru-based OER catalysts towards scalable application.
基金supported by the International Science and Technol-ogy Cooperation Program of China(Project No.2011DFA32770)the National Natural Science Foundation of China(Project No.31701651,32060516)+3 种基金the Science and Technology Program of Jiangxi Province(Project No.20143ACG70015)the Natural Science Foundation of Jiangxi Province(Project No.20224BAB215050)the Central Govern-ment Guide Local Special Fund Project for Scientific and Technological Development of Jiangxi Province(Project No.20212ZDD02008,20221ZDD02001)the Research Program of State Key Laboratory of Food Science and Technology,Nanchang University(Project No.SKLFZZA-201910,SKLF-ZZB-201916 and SKLF-ZZB-202135).
文摘In this study,Cinnamomum camphora seed kernel protein isolate(CPI)-dextran(DX)model system was used to investigate the impacts of reaction temperatures(70-100℃)and times(1-4 h)on the structure,functional properties and volatile compounds of Maillard reaction products(MRPs).The formation of MRPs was confirmed by SDS-PAGE,ultraviolet absorption and degree of glycation.Fourier transform infrared(FTIR)and circular dichroism(CD)spectroscopy showed that the secondary structure of MRPs tended to be more regular than native CPI.Moreover,MRPs had a lower free sulfhydryl group content and higher surface hydrophobicity than native CPI.Fluorescence spectra revealed that the tryptophan residues of CPI were transferred to a more hydrophobic microenvironment.The solubility and emulsifying stability of CPI were decreased,while the foaming activity,foaming stability,emulsion stability and apparent viscosity of CPI were significantly improved(p<0.05)after Maillard reaction.Furthermore,MRPs exhibited significantly improved(p<0.05)thermal stability and ABTS^(+)•radical scavenging activity than native CPI,while the DPPH+radical scavenging activity and ferric reducing power were decreased.In addition,volatile compounds,including aldehydes,ketones,benzenes and esters,were identified in MRPs.These results provide a theoretical guidance for future studies on CPI-DX conjugates.
基金supported by the National Key R&D Program of China(No.2022YFB4002000)the National Natural Science Foundation of China(No.22232004)+2 种基金the Strategic priority research program of CAS(No.XDA21090400)the Jilin Province Science and Technology Development Program(NOs.20210301008GX and 20210502002ZP)the Jilin Province Development and Reform Commission Program(No.2023C032-6).
文摘Stable and efficient single atom catalysts(SACs)are highly desirable yet challenging in catalyzing acidic oxygen evolution reaction(OER).Herein,we report a novel iridium single atom catalyst structure,with atomic Ir doped in tetragonal PdO matrix(IrSAs-PdO)via a lattice-confined strategy.The optimized IrSAs-PdO-0.10 exhibited remarkable OER activity with an overpotential of 277 mV at 10 mA·cm^(-2) and long-term stability of 1000 h in 0.5 M H_(2)SO_(4).Furthermore,the turnover frequency attains 1.6 s^(-1) at an overpotential of 300 mV with a 24-fold increase in the intrinsic activity.The high activity originates from isolated iridium sites with low valence states and decreased Ir–O bonding covalency,and the excellent stability is a result of the effective confinement of iridium sites by Ir–O–Pd motifs.Moreover,we demonstrated for the first time that SACs have great potential in realizing ultralow loading of iridium(as low as microgram per square center meter level)in a practical water electrolyzer.
基金supported in part by the National Natural Science Foundation of China under Grant (No. 61472292)the key technology research of new-generation high-speed and high-level security chip for smart grid (No. 526816160015)in part by the Technological Innovation of Hubei Province (Major Special Project, No. 2018AAA046)
文摘Masking is one of the most commonly used Side-Channel Attack （SCA） countermeasures and is built on a security framework, such as the ISW framework, and ensures theoretical security through secret sharing. Unfortunately, the theoretical security cannot guarantee practical security, because several possible weaknesses may exist in the actual implementation. These weaknesses likely come from the masking schemes or are introduced by the implementation methods. Finding the possible weakness of the masking scheme is an interesting and important issue for real applications. In this paper, the possible weaknesses for masking schemes in Field- Programmable Gate Array （FPGA） design are discussed. It was found that the combinational circuit is the key to the security of masking schemes. The Toggle Count （TC） method and its extension are utilized to evaluate the security of masking schemes in the design phase and the implementation phase separately. Comparing different logic-level simulators for the Xilinx FPGA platform, the behavioral and post-translate simulations are considered as the analysis method in the design phase, while the post-map and the post-route simulations are used to find the weakness during the implementation phase. Moreover, a Standard Delay Format （SDF） based improvement scheme is proposed to significantly increase the effectiveness of the TC model.
