In this paper we investigate the nearly small twist mappings with intersection property. With a certain non-degenerate condition, we proved that the most of invariant tori of the original small twist mappings will sur...In this paper we investigate the nearly small twist mappings with intersection property. With a certain non-degenerate condition, we proved that the most of invariant tori of the original small twist mappings will survive afer small perturtations. The persisted invariant tori are close to the unperturbed ones when the perturbation are small. The orbits reduced by those mappings are quasi-periodic in the invariant tori with the frequences closing to the original ones.展开更多
Vehicle delay is an important measure to evaluate the signal timings of signalized intersections.When optimization the signal control parameters, delays of vehicles from all approach directions of an intersection shou...Vehicle delay is an important measure to evaluate the signal timings of signalized intersections.When optimization the signal control parameters, delays of vehicles from all approach directions of an intersection should be considered. Based on the analysis of the vehicle delay on an approach of intersection, directed against the typical condition of a congested intersection-over-saturated condition, the paper has analyzed and inferred the intersection delay dynamic formulation, and has established the relation between intersection delay,the signal timings, vehicle arrival rate and the queue lengths, and that provides useful information for understanding vehicle delay of signalized intersection and for establishing performance index function of signal timing optimization.展开更多
现有会话推荐模型长于提取用户当前偏好,但不善于捕捉用户兴趣随时间和情境的动态演变,难以从短时交互序列数据中提取项目之间的隐性关系.本文提出了一种基于邻域与超图协作学习会话推荐模型(Neighborhood and Hypergraph Collaboration...现有会话推荐模型长于提取用户当前偏好,但不善于捕捉用户兴趣随时间和情境的动态演变,难以从短时交互序列数据中提取项目之间的隐性关系.本文提出了一种基于邻域与超图协作学习会话推荐模型(Neighborhood and Hypergraph Collaboration for session-based Recommendation model,NHG-Rec),首先综合利用自适应多跳超图卷积和邻域卷积,以同时捕捉项目间的显性和隐性关系;然后利用基于上下文感知的位置动态注意力机制,来挖掘会话内各项目的重要程度,从而捕捉用户实时兴趣;再采用多视图会话嵌入,通过局部-全局对比学习策略,以期捕捉项目间的多维特征、辨别语义差异.实验结果表明:对于Tmall、Diginetica、Nowplaying这3个基准数据集,相比SR-GNN、GCE-GNN、DHCN等主流基准模型,该模型的P@10、P@20、MRR@10、MRR@20性能指标分别平均提升了12.38%、5.47%、6.53%、6.39%.NHG-Rec模型能够捕捉用户兴趣的动态变化和项目间的多维关系.展开更多
随着工业化和城市化的快速发展,环境监测的重要性日益凸显,然而传统监测方法受限于高昂成本、布局困难和维护挑战,难以实现全面和实时的监测.群智感知作为一种新兴的环境监测方法,利用广泛使用的高度智能设备和集成传感器进行环境数据...随着工业化和城市化的快速发展,环境监测的重要性日益凸显,然而传统监测方法受限于高昂成本、布局困难和维护挑战,难以实现全面和实时的监测.群智感知作为一种新兴的环境监测方法,利用广泛使用的高度智能设备和集成传感器进行环境数据的大规模收集和实时传输.但现有研究很少同时考虑到数据隐私保护、工作平衡以及系统成本,导致在实际应用中难以达到预期效果.为解决这一问题,本文提出一种能适用于环境监测群智感知的低成本、高效率方法(Adaptive Federated Learning based Crowd Sensing algorithm for Environmental Monitoring,AFL-CSEM).具体而言,考虑系统中的资源限制、设备异构性和数据非独立同分布等挑战,本文结合群智感知与联邦学习技术进行了系统建模,在用户设备上进行本地模型训练,仅共享模型参数,有效保护数据隐私;进行系统的收敛性分析,得到基于联邦学习的群智感知算法在非独立同分布数据分布下的收敛界限;为了减少设备异构性影响,依据收敛性分析的结果,设计一种自适应控制方法,动态调整局部更新频率和批大小,以适应异构与动态的监测环境.通过在真实数据集上的比较,所有实验结果一致证明了本文所提出算法的有效性,AFL-CSEM算法在减少计算和通信开销、降低经济成本的同时,提升了模型训练的效率与精度,为环境监测领域的群智感知提供了一种新颖且具有参考价值的解决方案.展开更多
The advancement of various types of fluorescent nanoparticles is crucial for enhancing the application of lateral flow immunoassays(LFIA)across multiple fields.Currently,the fluorescent nanoparticles utilized in LFIA ...The advancement of various types of fluorescent nanoparticles is crucial for enhancing the application of lateral flow immunoassays(LFIA)across multiple fields.Currently,the fluorescent nanoparticles utilized in LFIA predominantly consist of traditional dye-doped nanoparticles or aggregation-induced luminescence dye-doped nanoparticles.The reliance on specific types of nanoparticles limits the diversity of signal reporting groups available for LFIA.Herein,we developed a solid-state luminescent dye-doped nanoparticles(SLDNPs)-based LFIA system with exceptional stability for the detection of C-reactive protein(CRP)in serum.The synthesis of SLD_(520)NP_(S)was simplicity,efficient and eco-friendly,which was ideal for large-scale production of the LFIA test strip.And the SLD_(520)NP_(S)exhibits superior fluorescence quantum yield(49%),fully guarantees the performance of the LFIA test strip.The constructed SLD_(520)NPsm Ab1-based LFIA demonstrated a satisfactory linear relationship with CRP concentrations ranging from 0.5 ng/mL to 100 ng/mL,with limits of detection(LOD)of 0.78 ng/mL and a visible LOD of 1 ng/mL using a handheld 405 nm lamp.Furthermore,the developed LFIA exhibited excellent recoveries in serum,ranging from 94.45%to 102.5%.Overall,the outstanding performance of the SLD_(520)NPs-mAb1-based LFIA indicates that solid-state luminescent dyes have significant potential applications in the field of LFIA.展开更多
The traditional nanozymes-based ratiometric fluorescence sensing platforms usually necessitate the supplementary addition of fluorescent probes,therefore greatly restricting its convenient and broad application.In thi...The traditional nanozymes-based ratiometric fluorescence sensing platforms usually necessitate the supplementary addition of fluorescent probes,therefore greatly restricting its convenient and broad application.In this study,a highly sensitive and selective ratiometric fluorescence platform for alkaline phosphatase(ALP)detection was established,only employing Prussian blue(PB)nanozymes and a commercially available chromogen of o-phenylenediamine(OPD).PB nanozymes with remarkable peroxidaselike(POD-like)activity can effectively catalyze OPD chromogen to yield 2,3-diaminophenazine(OPDox)with an intense yellow fluorescence at 573 nm emission peak.Target ALP can facilitate ascorbic acid 2-phosphate(AAP)dephosphorylation to generate phosphate and ascorbic acid(AA).Significantly,both these two resultant hydrolysis products could effectively decrease the OPDox generation via a dualpath based inhibition on the PB nanozymes POD-like activity.On the other hand,the generated dehydroascorbic acid(DHAA)from AA oxidation would exclusively react with OPD chromogen to yield3-(dihydroxyethyl)furo[3,4-b]quinoxaline-1-one(DFQ)with a strong blue fluorescent signal at 434nm,which further providing a significant enhancement on the sensing selectivity of ALP detection.As a result,an increased yellow fluorescence of OPDox and decreased blue fluorescence of DFQ could be clearly observed with different ALP addition.A robust linear relationship between the fluorescence ratio of F_(434)/F_(573)and ALP activity ranging from 0.25U/L to 6U/L was obtained,with a low detection limit of 0.112 U/L.This proposed method demonstrates high sensitivity,excellent selectivity,cost-effectiveness,and operational simplicity,yet enabling an effective detection of ALP levels in human serum.展开更多
By using Lagrangian method, the flow properties of a dusty-gas point source in a supersonic free stream were studied and the particle parameters in the near-symmetry-axis region were obtained . It is demonstrated that...By using Lagrangian method, the flow properties of a dusty-gas point source in a supersonic free stream were studied and the particle parameters in the near-symmetry-axis region were obtained . It is demonstrated that fairly inertial particles travel along oscillating and intersecting trajectories between the bow and termination shock waves . In this region, formation of ' mufti- layer structure' in panicle distribution with alternating low- and high density layers is revealed. Moreover, sharp accumulation of particles occurs near the envelopes of particle trajectories .展开更多
2023年春季,我国西南地区发生了严重的气象干旱,对当地社会经济造成严重影响。为深入认识这次干旱事件的成因、并为未来西南地区春旱的预测提供科学依据,本文利用站点观测数据、美国国家环境预测中心和国家大气研究中心(National Center...2023年春季,我国西南地区发生了严重的气象干旱,对当地社会经济造成严重影响。为深入认识这次干旱事件的成因、并为未来西南地区春旱的预测提供科学依据,本文利用站点观测数据、美国国家环境预测中心和国家大气研究中心(National Centers for Environmental Prediction/National Center for Atmospheric Research,NCEP/NCAR)再分析数据、美国国家海洋和大气管理局(National Oceanic and Atmospheric Administration,NOAA)的海表温度等,采用T-N波作用通量和合成分析等方法,从海温和热带大气季节内振荡(Madden-Julian Oscillation,MJO)的角度深入探讨此次春旱成因。结果表明:(1)2023年我国西南春旱是高温干旱复合事件,3月干旱发生在中部,4月干旱加剧并向西扩展,5月干旱持续。(2)3月北太平洋的马蹄形海温异常导致西风急流偏南偏西,抑制了西南地区的降水。(3)4月印度洋暖海温通过Kelvin波导致孟加拉湾附近的反气旋式环流异常,西北太平洋暖海温通过Rossby波导致南海至菲律宾的气旋式环流异常,造成西南地区南部出现偏北风,导致水汽辐散,加剧干旱。(4)5月MJO长时间维持在西太平洋,通过Gill响应引发南海至菲律宾对流层低层的气旋异常,减少偏南水汽的输送,从而使得西南干旱持续。展开更多
文摘In this paper we investigate the nearly small twist mappings with intersection property. With a certain non-degenerate condition, we proved that the most of invariant tori of the original small twist mappings will survive afer small perturtations. The persisted invariant tori are close to the unperturbed ones when the perturbation are small. The orbits reduced by those mappings are quasi-periodic in the invariant tori with the frequences closing to the original ones.
基金Sponsored by the Mulfidiscipline Scientific Research Foundation of Harbin Institute of Technology( Grant No. HIT. MD. 2002.28)
文摘Vehicle delay is an important measure to evaluate the signal timings of signalized intersections.When optimization the signal control parameters, delays of vehicles from all approach directions of an intersection should be considered. Based on the analysis of the vehicle delay on an approach of intersection, directed against the typical condition of a congested intersection-over-saturated condition, the paper has analyzed and inferred the intersection delay dynamic formulation, and has established the relation between intersection delay,the signal timings, vehicle arrival rate and the queue lengths, and that provides useful information for understanding vehicle delay of signalized intersection and for establishing performance index function of signal timing optimization.
文摘现有会话推荐模型长于提取用户当前偏好,但不善于捕捉用户兴趣随时间和情境的动态演变,难以从短时交互序列数据中提取项目之间的隐性关系.本文提出了一种基于邻域与超图协作学习会话推荐模型(Neighborhood and Hypergraph Collaboration for session-based Recommendation model,NHG-Rec),首先综合利用自适应多跳超图卷积和邻域卷积,以同时捕捉项目间的显性和隐性关系;然后利用基于上下文感知的位置动态注意力机制,来挖掘会话内各项目的重要程度,从而捕捉用户实时兴趣;再采用多视图会话嵌入,通过局部-全局对比学习策略,以期捕捉项目间的多维特征、辨别语义差异.实验结果表明:对于Tmall、Diginetica、Nowplaying这3个基准数据集,相比SR-GNN、GCE-GNN、DHCN等主流基准模型,该模型的P@10、P@20、MRR@10、MRR@20性能指标分别平均提升了12.38%、5.47%、6.53%、6.39%.NHG-Rec模型能够捕捉用户兴趣的动态变化和项目间的多维关系.
文摘随着工业化和城市化的快速发展,环境监测的重要性日益凸显,然而传统监测方法受限于高昂成本、布局困难和维护挑战,难以实现全面和实时的监测.群智感知作为一种新兴的环境监测方法,利用广泛使用的高度智能设备和集成传感器进行环境数据的大规模收集和实时传输.但现有研究很少同时考虑到数据隐私保护、工作平衡以及系统成本,导致在实际应用中难以达到预期效果.为解决这一问题,本文提出一种能适用于环境监测群智感知的低成本、高效率方法(Adaptive Federated Learning based Crowd Sensing algorithm for Environmental Monitoring,AFL-CSEM).具体而言,考虑系统中的资源限制、设备异构性和数据非独立同分布等挑战,本文结合群智感知与联邦学习技术进行了系统建模,在用户设备上进行本地模型训练,仅共享模型参数,有效保护数据隐私;进行系统的收敛性分析,得到基于联邦学习的群智感知算法在非独立同分布数据分布下的收敛界限;为了减少设备异构性影响,依据收敛性分析的结果,设计一种自适应控制方法,动态调整局部更新频率和批大小,以适应异构与动态的监测环境.通过在真实数据集上的比较,所有实验结果一致证明了本文所提出算法的有效性,AFL-CSEM算法在减少计算和通信开销、降低经济成本的同时,提升了模型训练的效率与精度,为环境监测领域的群智感知提供了一种新颖且具有参考价值的解决方案.
基金supported by the National Natural Science Foundation of China(Nos.22064014,21765013)the Science and Technology Development Plan Project of Lanzhou(No.20211-146)+3 种基金the Science and Technology Project of Gansu Province(Nos.21YF5FA071,21JR7RA538)the Industrial Support Programme for Higher Education Institutions Project(Nos.2023CYZC-69,2024CYCZ-05)the 2023 Gansu Provincial Key Talent Project(No.2023RCXM26)a Gansu province postdoctoral grant(No.00247)。
文摘The advancement of various types of fluorescent nanoparticles is crucial for enhancing the application of lateral flow immunoassays(LFIA)across multiple fields.Currently,the fluorescent nanoparticles utilized in LFIA predominantly consist of traditional dye-doped nanoparticles or aggregation-induced luminescence dye-doped nanoparticles.The reliance on specific types of nanoparticles limits the diversity of signal reporting groups available for LFIA.Herein,we developed a solid-state luminescent dye-doped nanoparticles(SLDNPs)-based LFIA system with exceptional stability for the detection of C-reactive protein(CRP)in serum.The synthesis of SLD_(520)NP_(S)was simplicity,efficient and eco-friendly,which was ideal for large-scale production of the LFIA test strip.And the SLD_(520)NP_(S)exhibits superior fluorescence quantum yield(49%),fully guarantees the performance of the LFIA test strip.The constructed SLD_(520)NPsm Ab1-based LFIA demonstrated a satisfactory linear relationship with CRP concentrations ranging from 0.5 ng/mL to 100 ng/mL,with limits of detection(LOD)of 0.78 ng/mL and a visible LOD of 1 ng/mL using a handheld 405 nm lamp.Furthermore,the developed LFIA exhibited excellent recoveries in serum,ranging from 94.45%to 102.5%.Overall,the outstanding performance of the SLD_(520)NPs-mAb1-based LFIA indicates that solid-state luminescent dyes have significant potential applications in the field of LFIA.
基金supported by the National Natural Science Foundation of China(No.22064014)the Science and Technology Development Plan Project of Lanzhou(No.2021–1-146)+2 种基金the Science and Technology Project of Gansu Province(Nos.21YF5FA071,21JR7RA538)the Industrial Support Programme for Higher Education Institutions Project(Nos.2023CYZC-69,2024CYCZ-05)the 2023 Gansu Provincial Key Talent Project(No.2023RCXM26)。
文摘The traditional nanozymes-based ratiometric fluorescence sensing platforms usually necessitate the supplementary addition of fluorescent probes,therefore greatly restricting its convenient and broad application.In this study,a highly sensitive and selective ratiometric fluorescence platform for alkaline phosphatase(ALP)detection was established,only employing Prussian blue(PB)nanozymes and a commercially available chromogen of o-phenylenediamine(OPD).PB nanozymes with remarkable peroxidaselike(POD-like)activity can effectively catalyze OPD chromogen to yield 2,3-diaminophenazine(OPDox)with an intense yellow fluorescence at 573 nm emission peak.Target ALP can facilitate ascorbic acid 2-phosphate(AAP)dephosphorylation to generate phosphate and ascorbic acid(AA).Significantly,both these two resultant hydrolysis products could effectively decrease the OPDox generation via a dualpath based inhibition on the PB nanozymes POD-like activity.On the other hand,the generated dehydroascorbic acid(DHAA)from AA oxidation would exclusively react with OPD chromogen to yield3-(dihydroxyethyl)furo[3,4-b]quinoxaline-1-one(DFQ)with a strong blue fluorescent signal at 434nm,which further providing a significant enhancement on the sensing selectivity of ALP detection.As a result,an increased yellow fluorescence of OPDox and decreased blue fluorescence of DFQ could be clearly observed with different ALP addition.A robust linear relationship between the fluorescence ratio of F_(434)/F_(573)and ALP activity ranging from 0.25U/L to 6U/L was obtained,with a low detection limit of 0.112 U/L.This proposed method demonstrates high sensitivity,excellent selectivity,cost-effectiveness,and operational simplicity,yet enabling an effective detection of ALP levels in human serum.
基金Foundation items : the National Natural Science Foundation of China ( NSFC grant No.90205024) the Russian Foundation for Basic Research (RFBR grant No. 02-01-00770) RFBR-NSFC grant No.99-01-39020)
文摘By using Lagrangian method, the flow properties of a dusty-gas point source in a supersonic free stream were studied and the particle parameters in the near-symmetry-axis region were obtained . It is demonstrated that fairly inertial particles travel along oscillating and intersecting trajectories between the bow and termination shock waves . In this region, formation of ' mufti- layer structure' in panicle distribution with alternating low- and high density layers is revealed. Moreover, sharp accumulation of particles occurs near the envelopes of particle trajectories .
文摘2023年春季,我国西南地区发生了严重的气象干旱,对当地社会经济造成严重影响。为深入认识这次干旱事件的成因、并为未来西南地区春旱的预测提供科学依据,本文利用站点观测数据、美国国家环境预测中心和国家大气研究中心(National Centers for Environmental Prediction/National Center for Atmospheric Research,NCEP/NCAR)再分析数据、美国国家海洋和大气管理局(National Oceanic and Atmospheric Administration,NOAA)的海表温度等,采用T-N波作用通量和合成分析等方法,从海温和热带大气季节内振荡(Madden-Julian Oscillation,MJO)的角度深入探讨此次春旱成因。结果表明:(1)2023年我国西南春旱是高温干旱复合事件,3月干旱发生在中部,4月干旱加剧并向西扩展,5月干旱持续。(2)3月北太平洋的马蹄形海温异常导致西风急流偏南偏西,抑制了西南地区的降水。(3)4月印度洋暖海温通过Kelvin波导致孟加拉湾附近的反气旋式环流异常,西北太平洋暖海温通过Rossby波导致南海至菲律宾的气旋式环流异常,造成西南地区南部出现偏北风,导致水汽辐散,加剧干旱。(4)5月MJO长时间维持在西太平洋,通过Gill响应引发南海至菲律宾对流层低层的气旋异常,减少偏南水汽的输送,从而使得西南干旱持续。
