The mechanisms underlying the pathophysiology of ischemic stroke are complex and multifactorial and include excitotoxicity,oxidative stress,inflammatory responses,and blood–brain barrier disruption.While vascular rec...The mechanisms underlying the pathophysiology of ischemic stroke are complex and multifactorial and include excitotoxicity,oxidative stress,inflammatory responses,and blood–brain barrier disruption.While vascular recanalization treatments such as thrombolysis and mechanical thrombectomy have achieved some success,reperfusion injury remains a significant contributor to the exacerbation of brain injury.This emphasizes the need for developing neuroprotective strategies to mitigate this type of injury.The purpose of this review was to examine the application of nanotechnology in the treatment of ischemic stroke,covering research progress in nanoparticlebased drug delivery,targeted therapy,and antioxidant and anti-inflammatory applications.Nanobased drug delivery systems offer several advantages compared to traditional therapies,including enhanced blood–brain barrier penetration,prolonged drug circulation time,improved drug stability,and targeted delivery.For example,inorganic nanoparticles,such as those based on CeO_(2),have been widely studied for their strong antioxidant capabilities.Biomimetic nanoparticles,such as those coated with cell membranes,have garnered significant attention owing to their excellent biocompatibility and targeting abilities.Nanoparticles can be used to deliver a wide range of neuroprotective agents,such as antioxidants(e.g.,edaravone),anti-inflammatory drugs(e.g.,curcumin),and neurotrophic factors.Nanotechnology significantly enhances the efficacy of these drugs while minimizing adverse reactions.Although nanotechnology has demonstrated great potential in animal studies,its clinical application still faces several challenges,including the long-term safety of nanoparticles,the feasibility of large-scale production,quality control,and the ability to predict therapeutic effects in humans.In summary,nanotechnology holds significant promise for the treatment of ischemic stroke.Future research should focus on further exploring the mechanisms of action of nanoparticles,developing multifunctional nanoparticles,and validating their safety and efficacy through rigorous clinical trials.Moreover,interdisciplinary collaboration is essential for advancing the use of nanotechnology in stroke treatment.展开更多
As the prevalence of obesity increases dramatically,obesity-associated cardiac dysfunction constitutes a considerable challenge to human health.This study aimed to identify more useful lipid/inflammatory markers to pr...As the prevalence of obesity increases dramatically,obesity-associated cardiac dysfunction constitutes a considerable challenge to human health.This study aimed to identify more useful lipid/inflammatory markers to predict the risk of obesity-associated cardiac dysfunction.By retrospectively analyzing the clinical characteristics of 5648 cardiac disease patients,we found that both the plasma level of high-density lipoprotein cholesterol(HDLC)and the blood monocyte count were significantly associated with impairment of the left ventricular ejection fraction(LVEF).Univariate and multivariate regression analyses revealed that the monocyte to HDL-C ratio(MHR)was a more powerful predictor of the risk of LVEF decline than either HDL-C or monocyte alone.Mediation analysis further revealed a mediating effect of a high MHR on the decline in obesity-associated cardiac systolic function.Collectively,our results demonstrate a superior role of MHR in predicting the risk of an obesityassociated decline in cardiac systolic function among routine metabolic/inflammatory markers.展开更多
Objective:Traditional Chinese medicine plays a significant role in the treatment of the pandemic of coronavirus disease 2019(COVID-19).Tanreqing Capsule(TRQC)was used in the treatment of COVID-19 patients in the Shang...Objective:Traditional Chinese medicine plays a significant role in the treatment of the pandemic of coronavirus disease 2019(COVID-19).Tanreqing Capsule(TRQC)was used in the treatment of COVID-19 patients in the Shanghai Public Health Clinical Center.This study aimed to investigate the clinical efficacy of TRQC in the treatment of COVID-19.Methods:A retrospective cohort study was conducted on 82 patients who had laboratory-confirmed mild and moderate COVID-19;patients were treated with TRQC in one designated hospital.The treatment and control groups consisted of 25 and 57 cases,respectively.The treatment group was given TRQC orally three times a day,three pills each time,in addition to conventional Western medicine treatments which were also administered to the control group.The clinical efficacy indicators,such as the negative conversion time of pharyngeal swab nucleic acid,the negative conversion time of fecal nucleic acid,the duration of negative conversion of pharyngeal-fecal nucleic acid,and the improvement in the level of immune indicators such as T-cell subsets(CD3,CD4 and CD45)were monitored.Results:COVID-19 patients in the treatment group,compared to the control group,had a shorter negative conversion time of fecal nucleic acid(4 vs.9 days,P=0.047)and a shorter interval of negative conversion of pharyngeal-fecal nucleic acid(0 vs.2 days,P=0.042).The level of CD3+T cells increased in the treatment group compared to the control group([317.09±274.39]vs.[175.02±239.95]counts/l L,P=0.030).No statistically significant differences were detected in the median improvement in levels of CD4+T cells(173 vs.107 counts/l L,P=0.208)and CD45+T cells(366 vs.141 counts/l L,P=0.117)between the treatment and control groups.Conclusion:Significant reductions in the negative conversion time of fecal nucleic acid and the duration of negative conversion of pharyngeal-fecal nucleic acid were identified in the treatment group as compared to the control group,illustrating the potential therapeutic benefits of using TRQC as a complement to conventional medicine in patients with mild and moderate COVID-19.The underlying mechanism may be related to the improved levels of the immune indicator CD3+T cells.展开更多
Rice-fish coculture(RFC)has aroused extensive concern for its contribution to food security and resource conservation,but whether it can improve soil phosphorus(P)availability and affect microbe-mediated P turnover re...Rice-fish coculture(RFC)has aroused extensive concern for its contribution to food security and resource conservation,but whether it can improve soil phosphorus(P)availability and affect microbe-mediated P turnover remains elusive.Herein,we conducted a microcosm experiment to assess the impacts of RFC combined with(50 mg P kg^(-1)as KH2PO4)and without inorganic P addition on P fractions,P availability,and phoD-harboring bacterial community composition.The results revealed that RFC without P addition significantly improved P availability and phosphatase activity in paddy soil,while soil available P(AP),pH,and microbial biomass P(MBP)contributed to regulating P fractions.Moreover,the phoD-harboring bacterial abundance was linked to phosphatase activity,AP,total carbon(TC),and total P(TP)contents,and the ratios of TC to total nitrogen(TN)and TN to TP.We also found that the keystone taxa of phoD-harboring bacteria contributed to phosphatase production as well as organic P mineralization,thereby improving P availability.Our findings suggest that RFC without P addition is beneficial for promoting the expression of phoD-harboring bacterial functions to improve the capacity of P mineralization.Overall,our study provides insights into the responses of phoD-harboring bacterial functions for P turnover to RFC combined with and without P addition,showing the potential utilization of P resources in agricultural soil and the contribution of phosphatase activity to P acquisition in agriculture ecosystem.展开更多
Objective Poxviruses are zoonotic pathogens that infect humans,mammals,vertebrates,and arthropods.However,the specific role of ticks in transmission and evolution of these viruses remains unclear.Methods Transcriptomi...Objective Poxviruses are zoonotic pathogens that infect humans,mammals,vertebrates,and arthropods.However,the specific role of ticks in transmission and evolution of these viruses remains unclear.Methods Transcriptomic and metatranscriptomic raw data from 329 sampling pools of seven tick species across five continents were mined to assess the diversity and abundance of poxviruses.Chordopoxviral sequences were assembled and subjected to phylogenetic analysis to trace the origins of the unblasted fragments within these sequences.Results Fifty-eight poxvirus species,representing two subfamilies and 20 genera,were identified,with 212 poxviral sequences assembled.A substantial proportion of AT-rich fragments were detected in the assembled poxviral genomes.These genomic sequences contained fragments originating from rodents,archaea,and arthropods.Conclusion Our findings indicate that ticks play a significant role in the transmission and evolution of poxviruses.These viruses demonstrate the capacity to modulate virulence and adaptability through horizontal gene transfer,gene recombination,and gene mutations,thereby promoting co-existence and co-evolution with their hosts.This study advances understanding of the ecological dynamics of poxvirus transmission and evolution and highlights the potential role of ticks as vectors and vessels in these processes.展开更多
The issues of fossil energy shortage and environmental pollution caused by the excessive consumption of conventional fossil fuels necessitates the exploration of renewable and clean energy sources such as hydrogen,whi...The issues of fossil energy shortage and environmental pollution caused by the excessive consumption of conventional fossil fuels necessitates the exploration of renewable and clean energy sources such as hydrogen,which is viable alternative to traditional energy sources in view of its high energy density and nonpolluting nature.In this regard,photocatalytic technology powered by inexhaustible solar energy is an ideal hydrogen production method.The recently developed copper-and zinc-based multinary metal sulfide(MMS)semiconductor photocatalysts exhibit the advantages of suitable bandgap,wide light-harvesting range,and flexible elemental composition,thus possessing great potential for achieving considerable photocatalytic hydrogen evolution(PHE)performance.Despite great progress has been achieved,the current photocatalysts still cannot meet the commercial application demands,which highlights the mechanisms understanding and optimization strategies for efficient PHE.Herein,the basic mechanisms of PHE,and effective optimization strategies are firstly introduced.Afterwards,the research process and the performance of copper-and zinc-based MMS photocatalysts,are thoroughly reviewed.Finally,the unresolved issues,and challenges hindering the achievement of overall water splitting have been discussed.展开更多
Defect engineering in metal organic frameworks(MOFs)has captured significant attention in the field of photocatalysis.A series of UiO-66(Ce)(UiO=University of Oslo)MOFs with different contents of missing-linker defect...Defect engineering in metal organic frameworks(MOFs)has captured significant attention in the field of photocatalysis.A series of UiO-66(Ce)(UiO=University of Oslo)MOFs with different contents of missing-linker defects have been developed for the photocatalytic selective oxidation of benzylamine(BA)and thioanisole(TA)under visible light.The introduction of missing-linker defects promotes the formation of unsaturated Ce sites with a high Ce3+content.It also generates a high concentration of oxygen vacancies.In situ Fourier transform infrared spectroscopy(FTIR)results revealed that BA and TA molecules were activated on coordinatively unsaturated Ce sites via the H-N…Ce and the C-S…Ce interactions,respectively.Simulated in situ electron paramagnetic resonance(EPR)data indicate that O_(2) activation and reduction occur at coordinatively unsaturated Ce^(3+)sites to form·O_(2)^(-).This is accelerated by the Ce^(3+)/Ce^(4+)redox cycle associated with the photogenerated electrons.The corresponding photogenerated holes are involved in the deprotonation of the activated BA and TA.The most active sample exhibits 98.4%and 95.5%conversion rates for BA and TA oxidation.Mechanisms for the molecular activation are proposed at the molecular level.展开更多
Superconducting radio-frequency(SRF)cavities are the core components of SRF linear accelerators,making their stable operation considerably important.However,the operational experience from different accelerator labora...Superconducting radio-frequency(SRF)cavities are the core components of SRF linear accelerators,making their stable operation considerably important.However,the operational experience from different accelerator laboratories has revealed that SRF faults are the leading cause of short machine downtime trips.When a cavity fault occurs,system experts analyze the time-series data recorded by low-level RF systems and identify the fault type.However,this requires expertise and intuition,posing a major challenge for control-room operators.Here,we propose an expert feature-based machine learning model for automating SRF cavity fault recognition.The main challenge in converting the"expert reasoning"process for SRF faults into a"model inference"process lies in feature extraction,which is attributed to the associated multidimensional and complex time-series waveforms.Existing autoregression-based feature-extraction methods require the signal to be stable and autocorrelated,resulting in difficulty in capturing the abrupt features that exist in several SRF failure patterns.To address these issues,we introduce expertise into the classification model through reasonable feature engineering.We demonstrate the feasibility of this method using the SRF cavity of the China accelerator facility for superheavy elements(CAFE2).Although specific faults in SRF cavities may vary across different accelerators,similarities exist in the RF signals.Therefore,this study provides valuable guidance for fault analysis of the entire SRF community.展开更多
Conductor materials with good mechanical performance as well as high electrical and thermal conductivities are particularly important to break through the current bottle-neck limit(~ 100 T) of pulsed magnets. Here, we...Conductor materials with good mechanical performance as well as high electrical and thermal conductivities are particularly important to break through the current bottle-neck limit(~ 100 T) of pulsed magnets. Here, we perform systematic studies on the elastic properties of the Cu–6wt% Ag alloy wire, which is a promising candidate material for the new-generation pulsed magnets, by employing two independent ultrasonic techniques, i.e., resonant ultrasound spectroscopy(RUS) and ultrasound pulse-echo experiments. Our RUS measurements manifest that the elastic properties of the Cu–6wt% Ag alloy wires can be improved by an electroplastic drawing procedure as compared with the conventional cold drawing. We also take this opportunity to test the availability of our newly-built ultrasound pulse-echo facility at the Wuhan National High Magnetic Field Center(WHMFC, China), and the results suggest that the elastic performance of the electroplastically-drawn Cu–6wt% Ag alloy wire remains excellent without anomalous softening under extreme conditions,e.g., in ultra-high magnetic field up to 50 T and nitrogen or helium cryogenic liquids.展开更多
A flexure hinge is a major component in designing compliant mechanisms that o ers unique possibilities in a wide range of application fields in which high positioning accuracy is required. Although various flexure hin...A flexure hinge is a major component in designing compliant mechanisms that o ers unique possibilities in a wide range of application fields in which high positioning accuracy is required. Although various flexure hinges with di erent configurations have been successively proposed, they are often designed based on designers' experiences and inspirations. This study presents a systematic method for topological optimization of flexure hinges by using the level set method. Optimization formulations are developed by considering the functional requirements and geometrical constraints of flexure hinges. The functional requirements are first constructed by maximizing the compliance in the desired direction while minimizing the compliances in the other directions. The weighting sum method is used to construct an objective function in which a self-adjust method is used to set the weighting factors. A constraint on the symmetry of the obtained configuration is developed. Several numerical examples are presented to demonstrate the validity of the proposed method. The obtained results reveal that the design of a flexure hinge starting from the topology level can yield more choices for compliant mechanism design and obtain better designs that achieve higher performance.展开更多
为高效控制汽车前围板振动噪声,弥补传统材料抑制低频振动性能的不足及易燃、环保性能低的缺陷,设计一种基于Kagome点阵的局域共振型夹芯超材料,建立单胞结构的有限元模型,计算并分析其能带结构、带隙产生机理和弹性波传播特性,以及关...为高效控制汽车前围板振动噪声,弥补传统材料抑制低频振动性能的不足及易燃、环保性能低的缺陷,设计一种基于Kagome点阵的局域共振型夹芯超材料,建立单胞结构的有限元模型,计算并分析其能带结构、带隙产生机理和弹性波传播特性,以及关键几何参数对带隙频段的影响,利用正交实验极差分析法(Statistical Product and Service Software Automatically,SPSSAU)对关键几何参数进行优化,同时开展基于该材料的汽车前围板隔振性能的研究。研究表明,所设计的Kagome点阵夹芯超材料能够实现低频带隙;增加圆块厚度和半径会使带隙频段整体向低频方向移动,且拓宽低频带隙;减小韧带宽度会使带隙频段向低频区域移动,且使带隙宽度减小。将优化后的Kagome点阵夹芯超材料应用于汽车前围板,可明显提高其隔振性能。展开更多
基金supported by the National Natural Science Foundation of China,Nos.82301093(to QC)and 22334004(to HY)the Fuzhou University Fund for Testing Precious Equipment,No.2025T038(to QC)。
文摘The mechanisms underlying the pathophysiology of ischemic stroke are complex and multifactorial and include excitotoxicity,oxidative stress,inflammatory responses,and blood–brain barrier disruption.While vascular recanalization treatments such as thrombolysis and mechanical thrombectomy have achieved some success,reperfusion injury remains a significant contributor to the exacerbation of brain injury.This emphasizes the need for developing neuroprotective strategies to mitigate this type of injury.The purpose of this review was to examine the application of nanotechnology in the treatment of ischemic stroke,covering research progress in nanoparticlebased drug delivery,targeted therapy,and antioxidant and anti-inflammatory applications.Nanobased drug delivery systems offer several advantages compared to traditional therapies,including enhanced blood–brain barrier penetration,prolonged drug circulation time,improved drug stability,and targeted delivery.For example,inorganic nanoparticles,such as those based on CeO_(2),have been widely studied for their strong antioxidant capabilities.Biomimetic nanoparticles,such as those coated with cell membranes,have garnered significant attention owing to their excellent biocompatibility and targeting abilities.Nanoparticles can be used to deliver a wide range of neuroprotective agents,such as antioxidants(e.g.,edaravone),anti-inflammatory drugs(e.g.,curcumin),and neurotrophic factors.Nanotechnology significantly enhances the efficacy of these drugs while minimizing adverse reactions.Although nanotechnology has demonstrated great potential in animal studies,its clinical application still faces several challenges,including the long-term safety of nanoparticles,the feasibility of large-scale production,quality control,and the ability to predict therapeutic effects in humans.In summary,nanotechnology holds significant promise for the treatment of ischemic stroke.Future research should focus on further exploring the mechanisms of action of nanoparticles,developing multifunctional nanoparticles,and validating their safety and efficacy through rigorous clinical trials.Moreover,interdisciplinary collaboration is essential for advancing the use of nanotechnology in stroke treatment.
基金supported by grants from the National Natural Science Foundation of China(Grant Nos.82430018 to Q.C.,82270361 and 82570402 to H.Z.)the Nanjing Medical University Undergraduate Innovation and Entrepreneurship Training Program Fund(Grant No.202410312138Y to C.Z.)the Basic Sciences of Jiangsu Higher Education Institutions(Grant No.22KJA310002 to H.Z.)。
文摘As the prevalence of obesity increases dramatically,obesity-associated cardiac dysfunction constitutes a considerable challenge to human health.This study aimed to identify more useful lipid/inflammatory markers to predict the risk of obesity-associated cardiac dysfunction.By retrospectively analyzing the clinical characteristics of 5648 cardiac disease patients,we found that both the plasma level of high-density lipoprotein cholesterol(HDLC)and the blood monocyte count were significantly associated with impairment of the left ventricular ejection fraction(LVEF).Univariate and multivariate regression analyses revealed that the monocyte to HDL-C ratio(MHR)was a more powerful predictor of the risk of LVEF decline than either HDL-C or monocyte alone.Mediation analysis further revealed a mediating effect of a high MHR on the decline in obesity-associated cardiac systolic function.Collectively,our results demonstrate a superior role of MHR in predicting the risk of an obesityassociated decline in cardiac systolic function among routine metabolic/inflammatory markers.
基金supported by Emergency Scientific Research Project of Shanghai Health Committee and Shanghai Administration of Traditional Chinese Medicine(No.2020YJ01)Shanghai Key Laboratory of Traditional Chinese Clinical Medicine(No.14DZ2273200)Shanghai Key Clinical Specialty(No.SHSLCZDZK05101)。
文摘Objective:Traditional Chinese medicine plays a significant role in the treatment of the pandemic of coronavirus disease 2019(COVID-19).Tanreqing Capsule(TRQC)was used in the treatment of COVID-19 patients in the Shanghai Public Health Clinical Center.This study aimed to investigate the clinical efficacy of TRQC in the treatment of COVID-19.Methods:A retrospective cohort study was conducted on 82 patients who had laboratory-confirmed mild and moderate COVID-19;patients were treated with TRQC in one designated hospital.The treatment and control groups consisted of 25 and 57 cases,respectively.The treatment group was given TRQC orally three times a day,three pills each time,in addition to conventional Western medicine treatments which were also administered to the control group.The clinical efficacy indicators,such as the negative conversion time of pharyngeal swab nucleic acid,the negative conversion time of fecal nucleic acid,the duration of negative conversion of pharyngeal-fecal nucleic acid,and the improvement in the level of immune indicators such as T-cell subsets(CD3,CD4 and CD45)were monitored.Results:COVID-19 patients in the treatment group,compared to the control group,had a shorter negative conversion time of fecal nucleic acid(4 vs.9 days,P=0.047)and a shorter interval of negative conversion of pharyngeal-fecal nucleic acid(0 vs.2 days,P=0.042).The level of CD3+T cells increased in the treatment group compared to the control group([317.09±274.39]vs.[175.02±239.95]counts/l L,P=0.030).No statistically significant differences were detected in the median improvement in levels of CD4+T cells(173 vs.107 counts/l L,P=0.208)and CD45+T cells(366 vs.141 counts/l L,P=0.117)between the treatment and control groups.Conclusion:Significant reductions in the negative conversion time of fecal nucleic acid and the duration of negative conversion of pharyngeal-fecal nucleic acid were identified in the treatment group as compared to the control group,illustrating the potential therapeutic benefits of using TRQC as a complement to conventional medicine in patients with mild and moderate COVID-19.The underlying mechanism may be related to the improved levels of the immune indicator CD3+T cells.
基金supported by the Key-Area Research and Development Program of Guangdong Province,China(No.2021B0202030002)the Science and Technology Planning Project of Guangdong Province,China(No.2019B030301007)+2 种基金the Guangdong Provincial Special Project of Rural Revitalization Strategy,China(No.(2021)12)the Joint Team Project of Guangdong Laboratory for Lingnan Modern Agriculture,China(No.NT2021010)the Innovation Team Construction Project of Modern Agricultural Industry Technology Systems of Guangdong Province,China(No.2022KJ105).
文摘Rice-fish coculture(RFC)has aroused extensive concern for its contribution to food security and resource conservation,but whether it can improve soil phosphorus(P)availability and affect microbe-mediated P turnover remains elusive.Herein,we conducted a microcosm experiment to assess the impacts of RFC combined with(50 mg P kg^(-1)as KH2PO4)and without inorganic P addition on P fractions,P availability,and phoD-harboring bacterial community composition.The results revealed that RFC without P addition significantly improved P availability and phosphatase activity in paddy soil,while soil available P(AP),pH,and microbial biomass P(MBP)contributed to regulating P fractions.Moreover,the phoD-harboring bacterial abundance was linked to phosphatase activity,AP,total carbon(TC),and total P(TP)contents,and the ratios of TC to total nitrogen(TN)and TN to TP.We also found that the keystone taxa of phoD-harboring bacteria contributed to phosphatase production as well as organic P mineralization,thereby improving P availability.Our findings suggest that RFC without P addition is beneficial for promoting the expression of phoD-harboring bacterial functions to improve the capacity of P mineralization.Overall,our study provides insights into the responses of phoD-harboring bacterial functions for P turnover to RFC combined with and without P addition,showing the potential utilization of P resources in agricultural soil and the contribution of phosphatase activity to P acquisition in agriculture ecosystem.
基金financially supported by the Shanghai New Three-Year Action Plan for Public Health(Grant No.GWVI-11.1-03)National Natural Science Foundation of China(Grant No.81872673).
文摘Objective Poxviruses are zoonotic pathogens that infect humans,mammals,vertebrates,and arthropods.However,the specific role of ticks in transmission and evolution of these viruses remains unclear.Methods Transcriptomic and metatranscriptomic raw data from 329 sampling pools of seven tick species across five continents were mined to assess the diversity and abundance of poxviruses.Chordopoxviral sequences were assembled and subjected to phylogenetic analysis to trace the origins of the unblasted fragments within these sequences.Results Fifty-eight poxvirus species,representing two subfamilies and 20 genera,were identified,with 212 poxviral sequences assembled.A substantial proportion of AT-rich fragments were detected in the assembled poxviral genomes.These genomic sequences contained fragments originating from rodents,archaea,and arthropods.Conclusion Our findings indicate that ticks play a significant role in the transmission and evolution of poxviruses.These viruses demonstrate the capacity to modulate virulence and adaptability through horizontal gene transfer,gene recombination,and gene mutations,thereby promoting co-existence and co-evolution with their hosts.This study advances understanding of the ecological dynamics of poxvirus transmission and evolution and highlights the potential role of ticks as vectors and vessels in these processes.
文摘The issues of fossil energy shortage and environmental pollution caused by the excessive consumption of conventional fossil fuels necessitates the exploration of renewable and clean energy sources such as hydrogen,which is viable alternative to traditional energy sources in view of its high energy density and nonpolluting nature.In this regard,photocatalytic technology powered by inexhaustible solar energy is an ideal hydrogen production method.The recently developed copper-and zinc-based multinary metal sulfide(MMS)semiconductor photocatalysts exhibit the advantages of suitable bandgap,wide light-harvesting range,and flexible elemental composition,thus possessing great potential for achieving considerable photocatalytic hydrogen evolution(PHE)performance.Despite great progress has been achieved,the current photocatalysts still cannot meet the commercial application demands,which highlights the mechanisms understanding and optimization strategies for efficient PHE.Herein,the basic mechanisms of PHE,and effective optimization strategies are firstly introduced.Afterwards,the research process and the performance of copper-and zinc-based MMS photocatalysts,are thoroughly reviewed.Finally,the unresolved issues,and challenges hindering the achievement of overall water splitting have been discussed.
基金supported by the National Natural Science Foundation of China(Nos.22272026 and 22272028)the 111 Project(No.D16008)Jinhong Bi thanks the Youth Talent Support Program of Fujian Province(No.00387077).
文摘Defect engineering in metal organic frameworks(MOFs)has captured significant attention in the field of photocatalysis.A series of UiO-66(Ce)(UiO=University of Oslo)MOFs with different contents of missing-linker defects have been developed for the photocatalytic selective oxidation of benzylamine(BA)and thioanisole(TA)under visible light.The introduction of missing-linker defects promotes the formation of unsaturated Ce sites with a high Ce3+content.It also generates a high concentration of oxygen vacancies.In situ Fourier transform infrared spectroscopy(FTIR)results revealed that BA and TA molecules were activated on coordinatively unsaturated Ce sites via the H-N…Ce and the C-S…Ce interactions,respectively.Simulated in situ electron paramagnetic resonance(EPR)data indicate that O_(2) activation and reduction occur at coordinatively unsaturated Ce^(3+)sites to form·O_(2)^(-).This is accelerated by the Ce^(3+)/Ce^(4+)redox cycle associated with the photogenerated electrons.The corresponding photogenerated holes are involved in the deprotonation of the activated BA and TA.The most active sample exhibits 98.4%and 95.5%conversion rates for BA and TA oxidation.Mechanisms for the molecular activation are proposed at the molecular level.
基金supported by the studies of intelligent LLRF control algorithms for superconducting RF cavities(No.E129851YR0)the National Natural Science Foundation of China(No.U22A20261)Applications of Artificial Intelligence in the Stability Study of Superconducting Linear Accelerators(No.E429851YR0)。
文摘Superconducting radio-frequency(SRF)cavities are the core components of SRF linear accelerators,making their stable operation considerably important.However,the operational experience from different accelerator laboratories has revealed that SRF faults are the leading cause of short machine downtime trips.When a cavity fault occurs,system experts analyze the time-series data recorded by low-level RF systems and identify the fault type.However,this requires expertise and intuition,posing a major challenge for control-room operators.Here,we propose an expert feature-based machine learning model for automating SRF cavity fault recognition.The main challenge in converting the"expert reasoning"process for SRF faults into a"model inference"process lies in feature extraction,which is attributed to the associated multidimensional and complex time-series waveforms.Existing autoregression-based feature-extraction methods require the signal to be stable and autocorrelated,resulting in difficulty in capturing the abrupt features that exist in several SRF failure patterns.To address these issues,we introduce expertise into the classification model through reasonable feature engineering.We demonstrate the feasibility of this method using the SRF cavity of the China accelerator facility for superheavy elements(CAFE2).Although specific faults in SRF cavities may vary across different accelerators,similarities exist in the RF signals.Therefore,this study provides valuable guidance for fault analysis of the entire SRF community.
基金Project supported by the National Key R&D Program of China (Grant Nos. 2022YFA1602602 and 2023YFA1609600)the National Natural Science Foundation of China (Grant No. U23A20580)+3 种基金the open research fund of Songshan Lake Materials Laboratory (Grant No. 2022SLABFN27)Beijing National Laboratory for Condensed Matter Physics (Grant No. 2024BNLCMPKF004)Guangdong Basic and Applied Basic Research Foundation (Grant No. 2022B1515120020)the interdisciplinary program of Wuhan National High Magnetic Field Center at Huazhong University of Science and Technology (Grant No. WHMFC202132)。
文摘Conductor materials with good mechanical performance as well as high electrical and thermal conductivities are particularly important to break through the current bottle-neck limit(~ 100 T) of pulsed magnets. Here, we perform systematic studies on the elastic properties of the Cu–6wt% Ag alloy wire, which is a promising candidate material for the new-generation pulsed magnets, by employing two independent ultrasonic techniques, i.e., resonant ultrasound spectroscopy(RUS) and ultrasound pulse-echo experiments. Our RUS measurements manifest that the elastic properties of the Cu–6wt% Ag alloy wires can be improved by an electroplastic drawing procedure as compared with the conventional cold drawing. We also take this opportunity to test the availability of our newly-built ultrasound pulse-echo facility at the Wuhan National High Magnetic Field Center(WHMFC, China), and the results suggest that the elastic performance of the electroplastically-drawn Cu–6wt% Ag alloy wire remains excellent without anomalous softening under extreme conditions,e.g., in ultra-high magnetic field up to 50 T and nitrogen or helium cryogenic liquids.
基金Supported by National Natural Science Foundation of China(Grant Nos.51605166,51820105007)Fundamental Research Funds for the Central Universities of China
文摘A flexure hinge is a major component in designing compliant mechanisms that o ers unique possibilities in a wide range of application fields in which high positioning accuracy is required. Although various flexure hinges with di erent configurations have been successively proposed, they are often designed based on designers' experiences and inspirations. This study presents a systematic method for topological optimization of flexure hinges by using the level set method. Optimization formulations are developed by considering the functional requirements and geometrical constraints of flexure hinges. The functional requirements are first constructed by maximizing the compliance in the desired direction while minimizing the compliances in the other directions. The weighting sum method is used to construct an objective function in which a self-adjust method is used to set the weighting factors. A constraint on the symmetry of the obtained configuration is developed. Several numerical examples are presented to demonstrate the validity of the proposed method. The obtained results reveal that the design of a flexure hinge starting from the topology level can yield more choices for compliant mechanism design and obtain better designs that achieve higher performance.
文摘为高效控制汽车前围板振动噪声,弥补传统材料抑制低频振动性能的不足及易燃、环保性能低的缺陷,设计一种基于Kagome点阵的局域共振型夹芯超材料,建立单胞结构的有限元模型,计算并分析其能带结构、带隙产生机理和弹性波传播特性,以及关键几何参数对带隙频段的影响,利用正交实验极差分析法(Statistical Product and Service Software Automatically,SPSSAU)对关键几何参数进行优化,同时开展基于该材料的汽车前围板隔振性能的研究。研究表明,所设计的Kagome点阵夹芯超材料能够实现低频带隙;增加圆块厚度和半径会使带隙频段整体向低频方向移动,且拓宽低频带隙;减小韧带宽度会使带隙频段向低频区域移动,且使带隙宽度减小。将优化后的Kagome点阵夹芯超材料应用于汽车前围板,可明显提高其隔振性能。
