检索结果-南通市图书馆

Frontiers of Structural and Civil Engineering 2024年第4期18卷 568-586页

作者： Fu-wei WU Yuan-Qi li Department of Structural Engineering Tongji UniversityShanghai 200092China State Key Laboratory of Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China

The derivation and validation of analytical equations for predicting the tensile initial stiffness of threadfixed one-side bolts(TOBs),connected to enclosed rectangular hollow section(RHS)columns,is presented in this *** unknown stiffness components are considered:the TOBs connection and the enclosed RHS ***,the trapezoidal thread of TOB,as an equivalent cantilevered beam subjected to uniformly distributed loads,is analyzed to determine the associated *** on the findings,the thread-shank serial-parallel stiffness model of TOB connection is *** analysis of the tensile stiffness of the enclosed RHS face due to two bolt forces,the four sidewalls are treated as rotation constraints,thus reducing the problem to a two-dimensional plate *** to the load superposition method,the deflection of the face plate is resolved into three components under various boundary and load *** to the plate deflection theory of Timoshenko,the analytical solutions for the three deflections are derived in terms of the variables of bolt spacing,RHS thickness,height to width ratio,***,the validity of the above stiffness equations is verified by a series of finite element(FE)models of T-stub *** proposed component stiffness equations are an effective supplement to the component-based method.

关键词： initial stiffness component based method thread-fixed one-side bolt rectangular hollow sections analytical equation

Accurately tracking hypersonic gliding vehicles via an LEO mega-constellation in relay tracking mode

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2024年第1期35卷 211-221页

作者： li Zhao WANG Yidi ZHENG wei College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China

In order to effectively defend against the threats of the hypersonic gliding vehicles(HGVs),HGVs should be tracked as early as possible,which is beyond the capability of the ground-based *** benefited by the developing megaconstellations in low-Earth orbit,this paper proposes a relay tracking mode to track HGVs to overcome the above *** whole tracking mission is composed of several tracking intervals with the same *** each tracking interval,several appropriate satellites are dispatched to track the *** that are planned to take part in the tracking mission are selected by a new derived observability *** tracking performances of the proposed tracking mode and the other two traditional tracking modes,including the stare and track-rate modes,are compared by *** results show that the relay tracking mode can track the whole trajectory of a HGV,while the stare mode can only provide a very short tracking ***,the relay tracking mode achieve higher tracking accuracy with fewer attitude controls than the track-rate mode.

关键词： target tracking mega-constellation hypersonic gliding vehicle(HGV) sensor selection observability analysis

An extended numerical model of the first exothermic peak for three dimensional printed cement-based materials

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2024年第1期18卷 80-88页

作者： wei JIANG Wenqian li Xi CHEN School of Materials Science and Engineering Tongji UniversityShanghai 200092China School of Civil Engineering Tongji UniversityShanghai 200092China

The first exothermic peak of cement-based material occurs a few minutes after mixing,and the properties of three dimensional(3D)printed concrete,such as setting time,are very sensitive to *** this background,based on the classical Park cement exothermic model of hydration,we propose and construct a numerical model of the first exothermic peak,taking into account the proportions of C_(3)S,C_(3)A and quicklime in *** calculated parameters are calibrated by means of relevant published exothermic test *** is found that this developed model offers a good simulation of the first exothermic peak of hydration for C_(3)S and C_(3)A proportions from 0 to 100% of cement clinker and reflects the effect of quicklime content at 8%-10%.The unique value of this research is provision of an important computational tool for applications that are sensitive to the first exothermic peak of hydration,such as 3D printing.

关键词： 3D printed cement-based materials cement hydration the first exothermic peak liquid quick-setting agent numerical model

Comprehensive Evaluation Method for Traffic Flow Data Quality Based on Grey Correlation Analysis and Particle Swarm Optimization

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Science and Systems Engineering 2024年第1期33卷 106-128页

作者： wei Ba Baojun Chen Qi li School of Automation and Electrical Engineering Dalian Jiaotong UniversityDalian116028China Faculty of Electronic Information and Electrical Engineering Dalian University of TechnologyDalian116023China

Nowadays,data are more and more used for intelligent modeling and prediction,and the comprehensive evaluation of data quality is getting more and more attention as a necessary means to measure whether the data are usable or ***,the comprehensive evaluation method of data quality mostly contains the subjective factors of the evaluator,so how to comprehensively and objectively evaluate the data has become a bottleneck that needs to be solved in the research of comprehensive evaluation *** order to evaluate the data more comprehensively,objectively and differentially,a novel comprehensive evaluation method based on particle swarm optimization(PSO)and grey correlation analysis(GCA)is presented in this *** first,an improved GCA evaluation model based on the technique for order preference by similarity to an ideal solution(TOPSIS)is ***,an objective function model of maximum difference of the comprehensive evaluation values is built,and the PSO algorithm is used to optimize the weights of the improved GCA evaluation model based on the objective function ***,the performance of the proposed method is investigated through parameter analysis.A performance comparison of traffic flow data is carried out,and the simulation results show that the maximum average difference between the evaluation results and its mean value(MDR)of the proposed comprehensive evaluation method is 33.24%higher than that of TOPSIS-GCA,and 6.86%higher than that of *** proposed method has better differentiation than other methods,which means that it objectively and comprehensively evaluates the data from both the relevance and differentiation of the data,and the results more effectively reflect the differences in data quality,which will provide more effective data support for intelligent modeling,prediction and other applications.

关键词： Data quality comprehensive evaluation particle swarm optimization grey correlation analysis traffic flow data

Early plasma exchange and continuous renal replacement therapy improve puerperal prognosis in hepatitis B virus-related acute-on-chronic liver failure in pregnancy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The First Five Years of a Phase Theory for Complex Systems and Networks

liver Research 2024年第2期8卷 118-126页

作者： lijuan li mingming Fan mi Zhou Pinglan Lu Jianrong liu Huimin Yi Xuxia wei Surgical Intensive Care Unit The Third Affiliated Hospital of Sun Yat-sen University Guangzhou Guangdong China

Background and aim Hepatitis B virus (HBV)-related gestational acute-on-chronic liver failure (ACLF) is a severe condition with limited treatment options. This study aimed to evaluate the efficacy and ideal timing of plasma exchange and continuous renal replacement therapy (CRRT) in managing pregnant women with HBV-related ACLF. Methods This study retrospectively analyzed 51 eligible patients with HBV-related gestational ACLF between 2009 and 2020. Patients admitted to the study were divided into a conventional treatment group and a new treatment group according to whether they received the new management protocol, which included more aggressive plasma exchange (PE) and CRRT strategies. All 19 pregnant women with hepatic encephalopathy (HE) were divided into an early treatment group and a non-early treatment group according to whether PE therapy was initiated within three days. Our study had two primary objectives. Firstly, we aimed to evaluate the impact of PE and CRRT on puerperal survival. Secondly, we sought to assess the effects of early PE and CRRT regimens on puerperal survival in women with HE. Results The levels of total bilirubin on the second day postpartum (D3), the third day postpartum (D4), and the fifth day postpartum (D6) were significantly lower in the new treatment group compared to the conventional treatment group ( P = 0.02, 0.01, and 0.02, respectively). The ALT of D3 was significantly elevated in the new treatment group compared to the conventional treatment group ( P = 0.02). The incidence of HE overall increased from prenatal to postpartum D4, peaked on D4, and then gradually decreased from the fourth day postpartum (D5) （ P = 0.027）. The first week after delivery revealed a significant difference in survival rate between the two groups, the conventional treatment group had statistically higher mortality rates compared to the new treatment group ( P = 0.002). Similarly, the entire puerperal period mortality rate of the conventional treatm

关键词： Acute-on-chronic liver failure (ACLF) liver disease in pregnancy Hepatitis B virus (HBV) Plasma exchange (PE) Continuous renal replacement therapy (CRRT) Hepatic encephalopathy (HE)

来源：评论

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第8期11卷 1728-1743页

作者： Dan Wang wei Chen li Qiu Division of Decision and Control Systems KTH Royal Institute of TechnologyStockholm 10044Sweden Department of Mechanics and Engineering Science&the State Key Laboratory for Turbulence and Complex Systems Peking UniversityBeijing 100871China Hong Kong University of Science and Technology Hong KongChinaand also with the Southern University of Science and TechnologyShenzhen 518055China

In this paper,we review the development of a phase theory for systems and networks in its first five years,represented by a trilogy:Matrix phases and their properties;The miMO LTI system phase response,its physical interpretations,the small phase theorem,and the sectored real lemma;The synchronization of a multi-agent network using phase *** the end,we also summarize a list of ongoing research on the phase theory and speculate what will happen in the next five years.

关键词： Consensus and synchronization matrix phases multi-agent systems phase theory sectored real lemma small phase theorem.

Enhancing Deep Learning Soil Moisture Forecasting Models by Integrating Physics-based Models

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2024年第7期41卷 1326-1341页

作者： Lu li Yongjiu DAI Zhongwang wei wei SHANGGUAN Nan wei Yonggen ZHANG Qingliang li Xian-Xiang li School of Atmospheric Sciences Sun Yat-sen UniversityGuangzhou 510275China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Guangzhou 510275China Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies Guangzhou 510275China Institute of Surface-Earth System Science School of Earth System ScienceTianjin UniversityTianjin 300072China College of Computer Science and Technology Changchun Normal UniversityChangchun 130123China

Accurate soil moisture(SM)prediction is critical for understanding hydrological ***-based(PB)models exhibit large uncertainties in SM predictions arising from uncertain parameterizations and insufficient representation of land-surface *** addition to PB models,deep learning(DL)models have been widely used in SM predictions ***,few pure DL models have notably high success rates due to lacking physical ***,we developed hybrid models to effectively integrate the outputs of PB models into DL models to improve SM *** this end,we first developed a hybrid model based on the attention mechanism to take advantage of PB models at each forecast time scale(attention model).We further built an ensemble model that combined the advantages of different hybrid schemes(ensemble model).We utilized SM forecasts from the Global Forecast System to enhance the convolutional long short-term memory(ConvLSTM)model for 1–16 days of SM *** performances of the proposed hybrid models were investigated and compared with two existing hybrid *** results showed that the attention model could leverage benefits of PB models and achieved the best predictability of drought events among the different hybrid ***,the ensemble model performed best among all hybrid models at all forecast time scales and different soil *** is highlighted that the ensemble model outperformed the pure DL model over 79.5%of in situ stations for 16-day *** findings suggest that our proposed hybrid models can adequately exploit the benefits of PB model outputs to aid DL models in making SM predictions.

关键词： soil moisture forecasting hybrid model deep learning ConvLSTM attention mechanism

A Two-stage Service-oriented Task Offloading Framework with Edge-cloud Collaboration: A Game Theory Approach

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

JOURNAL OF SYSTEMS SCIENCE AND SYSTEMS ENGINEERING 2024年第5期33卷 521-551页

作者： li, Shiyong li, Wenzhe liu, Huan Sun, wei Yanshan Univ Sch Econ & Management Qinhuangdao 066004 Peoples R China

With the fast development of Mobile Internet, data traffic generated by end devices is anticipated to witness substantial growth in the future years. However, processing tasks locally will cause latency due to the limited resources of the end devices. Edge-cloud collaboration, an effective solution for latency-sensitive applications, is attracting greater attention from both industry and academia. It combines the advantages of the cloud center with abundant computing resources and edge nodes with low-latency capabilities. In this paper, we propose a two-stage task offloading framework with edge-cloud collaboration to assist end devices processing latency-sensitive tasks either on the edge servers or in the cloud center. As for homogeneous task offloading, in the first stage, the competitive end devices offload tasks to the edge gateways. We formulate the selfish task offloading problem among end devices as a potential game. In the second stage, the edge nodes request resources from the cloud center to process end devices tasks due to their limited resources. Then, we consider the heterogeneous task offloading problem and use intelligent optimization algorithm to obtain the optimal offloading strategy. Simulation results show that the service prices of edge nodes influence the decisions and task offloading costs of end devices. We also verify the intelligent optimization algorithm can achieve optimal performance with low complexity and fast convergence.

关键词： Edge-cloud collaboration task offloading potential game simulation annealing algorithm ARTIFICIAL-INTELliGENCE RESOURCE-ALLOCATION INTERNET

Sarcocinerenoids A—J,Eight Rare Capnosane-Type and Two New Cage-Type Cembranoids with Promoting Angiogenesis Activity from the South China Sea Soft Coral Sarcophyton cinereum

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2024年第8期42卷 815-822页

作者： Yue mi Yanan Yang Xuli Tang Xiao Han Guoqiang li Key Laboratory of Marine Drugs Chinese Ministry of EducationSchool of Medicine and PharmacyOcean University of ChinaQingdaoShandong266003 China Laboratory of Marine Drugs and Biological Products National Laboratory for Marine Science and TechnologyQingdaoShandong266235 China College of Chemistry and Chemical Engineering Ocean University of ChinaQingdaoShandong266100 China

Backgroundand Originality Content,Cembranoids are a structurally diverse class of diterpenoids commonly occurring in marine and terrestrial organisms.(+)-Cembrene was the first reported cembranoid diterpenoid discovered in 1962,l and more than 1400 cembranoid diterpenoids have been identified in the last six decades,[2]Cembranoids are characterized by a 14-membered carbocyclic ring,an isopropyl group and three methyl groups,which form their core carbon *** processes such as oxidation,oxidative rearrangements and transannular cyclizations occur in organisms,leading to the formation of distinctive specialized metabolites such as epoxide,lactone,ester,furan,pyrane and other ringbased cembranoids.[2-3]

关键词： Soft coral Sarcophyton cinereum Capnosane-type cembranoids Absolute configurations Activities Natural products NMR spectroscopy liquid chromatography X-raydiffraction Chiral resolution

Dynamic Measurement of Intracellular pH Based on Bioluminescent Bacteria

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2024年第2期40卷 287-292页

作者： li Yaohua WANG wei State Key Laboratory of Analytical Chemistry for life Science School of Chemistry and Chemical EngineeringChemBIC(Chemistry and Biomedicine Innovation Center)Nanjing UniversityNanjing210023P.R.China

Intracellular pH(pHi)is a fundamental indicator of cellular physiological state,regulating cellular state and function,and has important research *** various probes for measuring intracellular pH were available,it is challenging to reflect pHi in real-time and reversible ***,we developed a whole-cell bioluminescent(BL)probe based on wild type BL bacteria,photobacterium phosphoreum(***),to determine and image *** dependence of BL intensity of *** on pH values of culture solutions was *** was found that BL intensity could respond to the change of pH values rapidly and *** further revealed that *** maintained pH homeostasis in the extracellular pH(pHe)within the range of 5.0–7.0,while intracellular pH homeostasis was destroyed at the alkaline *** method opens up the enormous potential of BL bacteria as an alternative to fluorescence for monitoring and imaging pHi.

关键词： Bioluminescence P.phosphoreum Intracellular pH Cell imaging