In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to ...In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to obtain the maximal positive definite solution of nonlinear matrix equation X+A^(*)X|^(-α)A=Q with the case 0<α≤1.Based on this method,a new iterative algorithm is developed,and its convergence proof is given.Finally,two numerical examples are provided to show the effectiveness of the proposed method.展开更多
In this paper,a novel method for investigating the particle-crushing behavior of breeding particles in a fusion blanket is proposed.The fractal theory and Weibull distribution are combined to establish a theoretical m...In this paper,a novel method for investigating the particle-crushing behavior of breeding particles in a fusion blanket is proposed.The fractal theory and Weibull distribution are combined to establish a theoretical model,and its validity was verified using a simple impact test.A crushable discrete element method(DEM)framework is built based on the previously established theoretical model.The tensile strength,which considers the fractal theory,size effect,and Weibull variation,was assigned to each generated particle.The assigned strength is then used for crush detection by comparing it with its maximum tensile stress.Mass conservation is ensured by inserting a series of sub-particles whose total mass was equal to the quality loss.Based on the crushable DEM framework,a numerical simulation of the crushing behavior of a pebble bed with hollow cylindrical geometry under a uniaxial compression test was performed.The results of this investigation showed that the particle withstands the external load by contact and sliding at the beginning of the compression process,and the results confirmed that crushing can be considered an important method of resisting the increasing external load.A relatively regular particle arrangement aids in resisting the load and reduces the occurrence of particle crushing.However,a limit exists to the promotion of resistance.When the strain increases beyond this limit,the distribution of the crushing position tends to be isotropic over the entire pebble bed.The theoretical model and crushable DEM framework provide a new method for exploring the pebble bed in a fusion reactor,considering particle crushing.展开更多
Effective partitioning is crucial for enabling parallel restoration of power systems after blackouts.This paper proposes a novel partitioning method based on deep reinforcement learning.First,the partitioning decision...Effective partitioning is crucial for enabling parallel restoration of power systems after blackouts.This paper proposes a novel partitioning method based on deep reinforcement learning.First,the partitioning decision process is formulated as a Markov decision process(MDP)model to maximize the modularity.Corresponding key partitioning constraints on parallel restoration are considered.Second,based on the partitioning objective and constraints,the reward function of the partitioning MDP model is set by adopting a relative deviation normalization scheme to reduce mutual interference between the reward and penalty in the reward function.The soft bonus scaling mechanism is introduced to mitigate overestimation caused by abrupt jumps in the reward.Then,the deep Q network method is applied to solve the partitioning MDP model and generate partitioning schemes.Two experience replay buffers are employed to speed up the training process of the method.Finally,case studies on the IEEE 39-bus test system demonstrate that the proposed method can generate a high-modularity partitioning result that meets all key partitioning constraints,thereby improving the parallelism and reliability of the restoration process.Moreover,simulation results demonstrate that an appropriate discount factor is crucial for ensuring both the convergence speed and the stability of the partitioning training.展开更多
The application of nitrogen fertilizers in agricultural fields can lead to the release of nitrogen-containing gases(NCGs),such as NO_(x),NH_(3) and N_(2)O,which can significantly impact regional atmospheric environmen...The application of nitrogen fertilizers in agricultural fields can lead to the release of nitrogen-containing gases(NCGs),such as NO_(x),NH_(3) and N_(2)O,which can significantly impact regional atmospheric environment and con-tribute to global climate change.However,there remain considerable research gaps in the accurate measurement of NCGs emissions from agricultural fields,hindering the development of effective emission reduction strategies.We improved an open-top dynamic chambers(OTDCs)system and evaluated the performance by comparing the measured and given fluxes of the NCGs.The results showed that the measured fluxes of NO,N_(2)O and NH_(3)were 1%,2%and 7%lower than the given fluxes,respectively.For the determination of NH_(3) concentration,we employed a stripping coil-ion chromatograph(SC-IC)analytical technique,which demonstrated an absorption efficiency for atmospheric NH_(3) exceeding 96.1%across sampling durations of 6 to 60 min.In the summer maize season,we utilized the OTDCs system to measure the exchange fluxes of NO,NH_(3),and N_(2)O from the soil in the North China Plain.Substantial emissions of NO,NH_(3) and N_(2)O were recorded following fertilization,with peaks of 107,309,1239 ng N/(m^(2)·s),respectively.Notably,significant NCGs emissions were observed following sus-tained heavy rainfall one month after fertilization,particularly with NH_(3) peak being 4.5 times higher than that observed immediately after fertilization.Our results demonstrate that the OTDCs system accurately reflects the emission characteristics of soil NCGs and meets the requirements for long-term and continuous flux observation.展开更多
Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The t...Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The traditional thermal elastic-plastic finite element method(TEP-FEM)can accurately predict welding deformation.However,its efficiency is low because of the complex nonlinear transient computation,making it difficult to meet the needs of rapid engineering evaluation.To address this challenge,this study proposes an efficient prediction method for welding deformation in marine thin plate butt welds.This method is based on the coupled temperature gradient-thermal strain method(TG-TSM)that integrates inherent strain theory with a shell element finite element model.The proposed method first extracts the distribution pattern and characteristic value of welding-induced inherent strain through TEP-FEM analysis.This strain is then converted into the equivalent thermal load applied to the shell element model for rapid computation.The proposed method-particularly,the gradual temperature gradient-thermal strain method(GTG-TSM)-achieved improved computational efficiency and consistent precision.Furthermore,the proposed method required much less computation time than the traditional TEP-FEM.Thus,this study lays the foundation for future prediction of welding deformation in more complex marine thin plates.展开更多
At present,there is currently a lack of unified standard methods for the determination of antimony content in groundwater in China.The precision and trueness of related detection technologies have not yet been systema...At present,there is currently a lack of unified standard methods for the determination of antimony content in groundwater in China.The precision and trueness of related detection technologies have not yet been systematically and quantitatively evaluated,which limits the effective implementation of environmental monitoring.In response to this key technical gap,this study aimed to establish a standardized method for determining antimony in groundwater using Hydride Generation–Atomic Fluorescence Spectrometry(HG-AFS).Ten laboratories participated in inter-laboratory collaborative tests,and the statistical analysis of the test data was carried out in strict accordance with the technical specifications of GB/T 6379.2—2004 and GB/T 6379.4—2006.The consistency and outliers of the data were tested by Mandel's h and k statistics,the Grubbs test and the Cochran test,and the outliers were removed to optimize the data,thereby significantly improving the reliability and accuracy.Based on the optimized data,parameters such as the repeatability limit(r),reproducibility limit(R),and method bias value(δ)were determined,and the trueness of the method was statistically evaluated.At the same time,precision-function relationships were established,and all results met the requirements.The results show that the lower the antimony content,the lower the repeatability limit(r)and reproducibility limit(R),indicating that the measurement error mainly originates from the detection limit of the method and instrument sensitivity.Therefore,improving the instrument sensitivity and reducing the detection limit are the keys to controlling the analytical error and improving precision.This study provides reliable data support and a solid technical foundation for the establishment and evaluation of standardized methods for the determination of antimony content in groundwater.展开更多
目的利用高分辨质谱鉴定银丹心脑通软胶囊的化学成分,与网络药理学研究结合,探讨银丹心脑通软胶囊“心脑同治”的活性成分及其潜在分子作用机制。方法基于UHPLC Q-Exactive Plus Orbitrap HRMS鉴定出的银丹心脑通软胶囊化学成分;通过TC...目的利用高分辨质谱鉴定银丹心脑通软胶囊的化学成分,与网络药理学研究结合,探讨银丹心脑通软胶囊“心脑同治”的活性成分及其潜在分子作用机制。方法基于UHPLC Q-Exactive Plus Orbitrap HRMS鉴定出的银丹心脑通软胶囊化学成分;通过TCMSP和SwissADME数据库,以口服利用度≥30%、类药性≥0.18和胃肠道吸收得分为“High”、类药性至少通过3个“Yes”来筛选活性成分,再检索活性成分的潜在作用靶点;通过OMIM、DisGeNET、GeneCards、TTD和PharmGKB数据库获取与心脑血管疾病相关靶基因。使用Venny软件获得两者的交集靶点,采用Cytoscape3.9.1分析软件结合STRING数据库对交集靶点进行蛋白互作网络分析和“药物-活性成分-靶点-疾病”网络构建,确定核心成分与靶点。利用DAVID数据库对银丹心脑通软胶囊治疗心脑血管疾病的潜在靶基因进行基因本体(GO)分析及京都基因与基因组百科全书富集分析(KEGG)预测其作用机制。最后将度值排名前5的靶点与主要活性成分进行分子对接模拟以验证网络药理学结果。结果通过UHPLC Q-Exactive Plus Orbitrap HRMS技术鉴定出银丹心脑通软胶囊中82个化学成分,主要包括黄酮类、有机酸类、菲醌类和二萜内酯类化合物;经TCMSP、SwissADME数据库筛选得到活性成分34个,如槲皮素、异樱花亭、二氢丹参酮I等,相对应的靶点389个,进一步筛选出治疗心脑血管疾病相关的潜在靶基因249个。GO和KEGG富集分析显示,银丹心脑通软胶囊的活性成分可能主要通过脂质与动脉粥样硬化通路、流体剪切应力与动脉粥样硬化、AGE-RAGE、IL-17、PI3K-Akt、HIF-1、TNF等通路来发挥治疗心脑血管疾病的作用。分子对接证实STAT3、HSP90AA1等与二氢丹参酮I、山柰酚、木犀草素等具有较高的亲和力。结论本研究初步预测了银丹心脑通软胶囊“心脑同治”其作用机制与动脉粥样硬化、炎症因子、细胞凋亡和氧化应激等方面有关,为后续作用机制的深度分析及临床应用提供科学依据。展开更多
EMS诱变育种是作物种质创新的重要手段,利用反向遗传学手段TILLING(targeting induced local lesions in genomes)筛选EMS突变体,是研究基因功能与获得优良种质的有效手段之一。本研究采用基于HRM,即高分辨率熔解曲线分析技术的TILLING...EMS诱变育种是作物种质创新的重要手段,利用反向遗传学手段TILLING(targeting induced local lesions in genomes)筛选EMS突变体,是研究基因功能与获得优良种质的有效手段之一。本研究采用基于HRM,即高分辨率熔解曲线分析技术的TILLING筛选方法(HRM-TILLING)进行突变体筛选技术体系的探索,通过设计不同大小扩增片段引物及Mg^(2+)浓度梯度,比较了不同条件下的HRM筛选效果,结果表明当扩增片段长度为150 bp,Mg^(2+)浓度为3.0 mmol/L时,可以有效区分DNA 16倍混合池中ARF7A基因存在碱基差异的两种茄子(Solanum melongena L.)材料,建立了一套基于HRM的茄子EMS突变体TILLING技术的筛选方法。以含有2000个M2株系的茄子(EP26)EMS突变体库为材料,筛选出1个ARF7A基因和2个Pad-1基因突变体株系。本研究建立的筛选技术体系可以快速、高效地筛选茄子EMS突变体,所筛选的突变体为进一步验证、获取茄子单性结实种质及功能基因组学的研究提供研究材料。展开更多
目的:建立贵州金丝桃指纹图谱及其化学成分分析。方法:采用UHPLC-DAD建立贵州金丝桃的指纹图谱,对12批样品的指纹图谱进行相似度分析、聚类分析和主成分分析。采用UHPLC-Q-Exactive Plus Orbitrap HRMS技术对贵州金丝桃中化学成分进行...目的:建立贵州金丝桃指纹图谱及其化学成分分析。方法:采用UHPLC-DAD建立贵州金丝桃的指纹图谱,对12批样品的指纹图谱进行相似度分析、聚类分析和主成分分析。采用UHPLC-Q-Exactive Plus Orbitrap HRMS技术对贵州金丝桃中化学成分进行鉴定。结果:指纹图谱分析表明12批贵州金丝桃相似度为0.928~0.999,聚类分析和主成分分析表明不同来源的贵州金丝桃样品的化学成分组成及其相对含量可能存在一定差异。高分辨质谱共鉴定出黄酮类、间苯三酚类、有机酸类等化合物69个。结论:该方法稳定、可靠,可有效地评价贵州金丝桃的质量,为进一步开发和利用贵州金丝桃提供依据。展开更多
基金Supported in part by Natural Science Foundation of Guangxi(2023GXNSFAA026246)in part by the Central Government's Guide to Local Science and Technology Development Fund(GuikeZY23055044)in part by the National Natural Science Foundation of China(62363003)。
文摘In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to obtain the maximal positive definite solution of nonlinear matrix equation X+A^(*)X|^(-α)A=Q with the case 0<α≤1.Based on this method,a new iterative algorithm is developed,and its convergence proof is given.Finally,two numerical examples are provided to show the effectiveness of the proposed method.
基金supported by Anhui Provincial Natural Science Foundation(2408085QA030)Natural Science Research Project of Anhui Educational Committee,China(2022AH050825)+3 种基金Medical Special Cultivation Project of Anhui University of Science and Technology(YZ2023H2C008)the Excellent Research and Innovation Team of Anhui Province,China(2022AH010052)the Scientific Research Foundation for High-level Talents of Anhui University of Science and Technology,China(2021yjrc51)Collaborative Innovation Program of Hefei Science Center,CAS,China(2019HSC-CIP006).
文摘In this paper,a novel method for investigating the particle-crushing behavior of breeding particles in a fusion blanket is proposed.The fractal theory and Weibull distribution are combined to establish a theoretical model,and its validity was verified using a simple impact test.A crushable discrete element method(DEM)framework is built based on the previously established theoretical model.The tensile strength,which considers the fractal theory,size effect,and Weibull variation,was assigned to each generated particle.The assigned strength is then used for crush detection by comparing it with its maximum tensile stress.Mass conservation is ensured by inserting a series of sub-particles whose total mass was equal to the quality loss.Based on the crushable DEM framework,a numerical simulation of the crushing behavior of a pebble bed with hollow cylindrical geometry under a uniaxial compression test was performed.The results of this investigation showed that the particle withstands the external load by contact and sliding at the beginning of the compression process,and the results confirmed that crushing can be considered an important method of resisting the increasing external load.A relatively regular particle arrangement aids in resisting the load and reduces the occurrence of particle crushing.However,a limit exists to the promotion of resistance.When the strain increases beyond this limit,the distribution of the crushing position tends to be isotropic over the entire pebble bed.The theoretical model and crushable DEM framework provide a new method for exploring the pebble bed in a fusion reactor,considering particle crushing.
基金funded by the Beijing Engineering Research Center of Electric Rail Transportation.
文摘Effective partitioning is crucial for enabling parallel restoration of power systems after blackouts.This paper proposes a novel partitioning method based on deep reinforcement learning.First,the partitioning decision process is formulated as a Markov decision process(MDP)model to maximize the modularity.Corresponding key partitioning constraints on parallel restoration are considered.Second,based on the partitioning objective and constraints,the reward function of the partitioning MDP model is set by adopting a relative deviation normalization scheme to reduce mutual interference between the reward and penalty in the reward function.The soft bonus scaling mechanism is introduced to mitigate overestimation caused by abrupt jumps in the reward.Then,the deep Q network method is applied to solve the partitioning MDP model and generate partitioning schemes.Two experience replay buffers are employed to speed up the training process of the method.Finally,case studies on the IEEE 39-bus test system demonstrate that the proposed method can generate a high-modularity partitioning result that meets all key partitioning constraints,thereby improving the parallelism and reliability of the restoration process.Moreover,simulation results demonstrate that an appropriate discount factor is crucial for ensuring both the convergence speed and the stability of the partitioning training.
基金supported by the National Key Research and Develop-ment Program(No.2022YFC3701103)the National Natural Science Foundation of China(Nos.42130714 and 41931287).
文摘The application of nitrogen fertilizers in agricultural fields can lead to the release of nitrogen-containing gases(NCGs),such as NO_(x),NH_(3) and N_(2)O,which can significantly impact regional atmospheric environment and con-tribute to global climate change.However,there remain considerable research gaps in the accurate measurement of NCGs emissions from agricultural fields,hindering the development of effective emission reduction strategies.We improved an open-top dynamic chambers(OTDCs)system and evaluated the performance by comparing the measured and given fluxes of the NCGs.The results showed that the measured fluxes of NO,N_(2)O and NH_(3)were 1%,2%and 7%lower than the given fluxes,respectively.For the determination of NH_(3) concentration,we employed a stripping coil-ion chromatograph(SC-IC)analytical technique,which demonstrated an absorption efficiency for atmospheric NH_(3) exceeding 96.1%across sampling durations of 6 to 60 min.In the summer maize season,we utilized the OTDCs system to measure the exchange fluxes of NO,NH_(3),and N_(2)O from the soil in the North China Plain.Substantial emissions of NO,NH_(3) and N_(2)O were recorded following fertilization,with peaks of 107,309,1239 ng N/(m^(2)·s),respectively.Notably,significant NCGs emissions were observed following sus-tained heavy rainfall one month after fertilization,particularly with NH_(3) peak being 4.5 times higher than that observed immediately after fertilization.Our results demonstrate that the OTDCs system accurately reflects the emission characteristics of soil NCGs and meets the requirements for long-term and continuous flux observation.
基金Supported by the National Natural Science Foundation of China under Grant No.51975138the High-Tech Ship Scientific Research Project from the Ministry of Industry and Information Technology under Grant No.CJ05N20the National Defense Basic Research Project under Grant No.JCKY2023604C006.
文摘Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The traditional thermal elastic-plastic finite element method(TEP-FEM)can accurately predict welding deformation.However,its efficiency is low because of the complex nonlinear transient computation,making it difficult to meet the needs of rapid engineering evaluation.To address this challenge,this study proposes an efficient prediction method for welding deformation in marine thin plate butt welds.This method is based on the coupled temperature gradient-thermal strain method(TG-TSM)that integrates inherent strain theory with a shell element finite element model.The proposed method first extracts the distribution pattern and characteristic value of welding-induced inherent strain through TEP-FEM analysis.This strain is then converted into the equivalent thermal load applied to the shell element model for rapid computation.The proposed method-particularly,the gradual temperature gradient-thermal strain method(GTG-TSM)-achieved improved computational efficiency and consistent precision.Furthermore,the proposed method required much less computation time than the traditional TEP-FEM.Thus,this study lays the foundation for future prediction of welding deformation in more complex marine thin plates.
基金supported by the National Natural Science Foundation of China(Project No.42307555).
文摘At present,there is currently a lack of unified standard methods for the determination of antimony content in groundwater in China.The precision and trueness of related detection technologies have not yet been systematically and quantitatively evaluated,which limits the effective implementation of environmental monitoring.In response to this key technical gap,this study aimed to establish a standardized method for determining antimony in groundwater using Hydride Generation–Atomic Fluorescence Spectrometry(HG-AFS).Ten laboratories participated in inter-laboratory collaborative tests,and the statistical analysis of the test data was carried out in strict accordance with the technical specifications of GB/T 6379.2—2004 and GB/T 6379.4—2006.The consistency and outliers of the data were tested by Mandel's h and k statistics,the Grubbs test and the Cochran test,and the outliers were removed to optimize the data,thereby significantly improving the reliability and accuracy.Based on the optimized data,parameters such as the repeatability limit(r),reproducibility limit(R),and method bias value(δ)were determined,and the trueness of the method was statistically evaluated.At the same time,precision-function relationships were established,and all results met the requirements.The results show that the lower the antimony content,the lower the repeatability limit(r)and reproducibility limit(R),indicating that the measurement error mainly originates from the detection limit of the method and instrument sensitivity.Therefore,improving the instrument sensitivity and reducing the detection limit are the keys to controlling the analytical error and improving precision.This study provides reliable data support and a solid technical foundation for the establishment and evaluation of standardized methods for the determination of antimony content in groundwater.
文摘目的利用高分辨质谱鉴定银丹心脑通软胶囊的化学成分,与网络药理学研究结合,探讨银丹心脑通软胶囊“心脑同治”的活性成分及其潜在分子作用机制。方法基于UHPLC Q-Exactive Plus Orbitrap HRMS鉴定出的银丹心脑通软胶囊化学成分;通过TCMSP和SwissADME数据库,以口服利用度≥30%、类药性≥0.18和胃肠道吸收得分为“High”、类药性至少通过3个“Yes”来筛选活性成分,再检索活性成分的潜在作用靶点;通过OMIM、DisGeNET、GeneCards、TTD和PharmGKB数据库获取与心脑血管疾病相关靶基因。使用Venny软件获得两者的交集靶点,采用Cytoscape3.9.1分析软件结合STRING数据库对交集靶点进行蛋白互作网络分析和“药物-活性成分-靶点-疾病”网络构建,确定核心成分与靶点。利用DAVID数据库对银丹心脑通软胶囊治疗心脑血管疾病的潜在靶基因进行基因本体(GO)分析及京都基因与基因组百科全书富集分析(KEGG)预测其作用机制。最后将度值排名前5的靶点与主要活性成分进行分子对接模拟以验证网络药理学结果。结果通过UHPLC Q-Exactive Plus Orbitrap HRMS技术鉴定出银丹心脑通软胶囊中82个化学成分,主要包括黄酮类、有机酸类、菲醌类和二萜内酯类化合物;经TCMSP、SwissADME数据库筛选得到活性成分34个,如槲皮素、异樱花亭、二氢丹参酮I等,相对应的靶点389个,进一步筛选出治疗心脑血管疾病相关的潜在靶基因249个。GO和KEGG富集分析显示,银丹心脑通软胶囊的活性成分可能主要通过脂质与动脉粥样硬化通路、流体剪切应力与动脉粥样硬化、AGE-RAGE、IL-17、PI3K-Akt、HIF-1、TNF等通路来发挥治疗心脑血管疾病的作用。分子对接证实STAT3、HSP90AA1等与二氢丹参酮I、山柰酚、木犀草素等具有较高的亲和力。结论本研究初步预测了银丹心脑通软胶囊“心脑同治”其作用机制与动脉粥样硬化、炎症因子、细胞凋亡和氧化应激等方面有关,为后续作用机制的深度分析及临床应用提供科学依据。
文摘目的:建立贵州金丝桃指纹图谱及其化学成分分析。方法:采用UHPLC-DAD建立贵州金丝桃的指纹图谱,对12批样品的指纹图谱进行相似度分析、聚类分析和主成分分析。采用UHPLC-Q-Exactive Plus Orbitrap HRMS技术对贵州金丝桃中化学成分进行鉴定。结果:指纹图谱分析表明12批贵州金丝桃相似度为0.928~0.999,聚类分析和主成分分析表明不同来源的贵州金丝桃样品的化学成分组成及其相对含量可能存在一定差异。高分辨质谱共鉴定出黄酮类、间苯三酚类、有机酸类等化合物69个。结论:该方法稳定、可靠,可有效地评价贵州金丝桃的质量,为进一步开发和利用贵州金丝桃提供依据。
