检索结果-南通市图书馆

Quantitative analysis of the macro-geomorphic evolution of Buyuan Basin, China

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Mountain Science 2019年第5期16卷 1035-1047页

作者： GU Zhen-kui FAN Hui song zhao-jun Yunnan Key Laboratory of International Rivers and Transboundary Eco-Security Yunnan University Institute of International Rivers and Eco-Security Yunnan University Shandong Provincial Key Laboratory of Depositional Mineralization & Sedimentary Minerals College of Earth Science and Engineering Shandong University of Science and Technology

Buyuan River, the largest tributary within the Chinese Lancang-Mekong River region downstream of the Jinghong Dam, plays a crucial role in river function and ecosystem service of the Lancang-Mekong River. The geomorphic evolution of a basin exerts a key control on riverine sediment input and transport. In this study, the geomorphic characteristics of Buyuan Basin are analyzed using morphological parameters, hydrodynamic parameters and the stream power river incision model. The results show that: 1) The slight north-south difference of channel density is most likely due to lithology and independent of tectonic activity and climate. 2) The weak tectonic activity and the low hypsometric integral(HI) value suggest that the macroscopic landform condition limits erosion and sediment production. 3) The logarithmic longitudinal profile of the main channel defends that the upstream sediments generated by erosion are easily deposited in the downstream channel, rather than being transported directly into the Lancang-Mekong River. 4) Approximately 74% of the reaches have annual average stream power less than 500 W·m^(-1). The narrow variation ranges of stream power in 50% of the river channel indicate relatively stable hydrodynamic environment. 5) Stream erosion and tectonic activity make the longitudinal profiles of the main channel and most tributary channels unstable. The wide range(between 22.01 and 45.58 with θ=0.43) of steepness index(k_(sn)) of longitudinal profiles implies differential uplift in the basin.

关键词： Geomorphic parameters Steepness index Stream power Lancang-Mekong River

维普期刊数据库

Exit options sustain altruistic punishment and decrease the second-order free-riders, but it is not a panacea

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2025年第1期68卷 278-291页

作者： Chen SHEN zhao song Lei SHI jun TANIMOTO Zhen WANG Faculty of Engineering Sciences Kyushu University School of Statistics and Mathematics Yunnan University of Finance and Economics School of Computing Engineering and Digital Technologies Teesside University School of Artificial Intelligence OPtics and Electro Nics (iOPEN) Northwestern Polytechnical University

Why do humans punish free riders at their own expense? This behavior represents an evolutionary puzzle in human societies. This study explores the role of exit strategies in fostering altruistic punishment within evolutionary game theory. We extend the traditional prisoner's dilemma model by incorporating exiters, players who opt out for a small payoff while nullifying their opponent's payoff, and altruistic punishers who cooperate and punish non-cooperators. Our findings indicate that in well-mixed populations, exiters destabilize defection but do not promote altruistic punishment. In social networks, however,exiters enable altruistic punishment via cyclic dominance among altruistic punishers, defectors, and exiters. Notably, this cyclic dominance is sensitive to exit payoffs; adjustments can lead to cyclic dominance of non-punishing cooperators, defectors, and exiters, or to a bi-stable state between these two types of cyclic dominance. These results highlight the nuanced impact of exiters on altruistic punishment, emphasizing the need for careful incentivization of exit behavior. While exiters can support altruistic punishment in networked populations, their effectiveness is not a panacea and is highly sensitive to exit payoffs, indicating limits to the voluntary participation mechanism.

关键词： evolutionary game theory altruistic punishment coexistence cyclic dominance bi-stable

A New Location Precision Model for Multi-Static Over-the-Horizon Radar System

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Wuhan University Journal of Natural Sciences 2010年第2期15卷 143-147页

作者： song jun, zhao Zhengyu, ZHOU Chen School of Electronic Information, Wuhan University, Wuhan 430072, Hubei, China School of Electronic Information Wuhan University Wuhan China

In this paper, a multi-static system working in an active way is made up of ionospheric oblique backscatter sounding system （IOBSS） and two separate receiving stations, which adopts discontinuous wave mechanism. We have advanced a new model that contains skywave condition to locate over-the-horizon targets. We use a single quasi-parabolic （QP） ionosphere model and an analytic ray-tracing program to obtain the coordinate registration （CR） index, which changes skywave group range to ground range. Also, IOBSS and other two receiving stations use this distance information to locate the target which is far away from the system. The analytic expression for the geometric dilution of precision （GDOP） under different station deployments are obtained, which shows GDOP is influenced by the system measurement precision, the stations＇ coordinates, and CR index. By computer simulation, we find that GDOP of isosceles right triangle deployment is smaller than that of line deployment and location precision will be improved with increasing base line length. The results indicate that this model is practicable with an acceptable range of error （less than 500 m under certain conditions in this paper）.

关键词： over-the-horizon radar (OTHR) multi-static coor-dinate registration target location

维普期刊数据库

Kaiyuqingre formula improves insulin secretion via regulating uncoupling protein-2 and KATPchannel

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2011年第17期124卷 2746-2750页

作者： TONG Xiao-lin song jun zhao Lin-hua JI Hang-yu Department of Endocrinology Guang'anmen Hospital China Academy of Chinese Medical Sciences Beijing 100053 China

Background Type 2 diabetes mellitus （T2DM） results from the complex association of insulin resistance and pancreatic β-cell failure. Recent studies have shown that patients diagnosed with T2DM present with a significant decrease in β-cell function, which can be further compromised during the progression of the disease. Several mechanisms have been shown to play a role in this process such as glucotoxicity and lipotoxicity, which contribute to accelerating insulin secretion. In this regard, Chinese medicine has a certain advantage. This experiment was performed to observe the effect of a Chinese medicine named Kaiyuqingre formula （KYQRF） on β-cell function and its mechanisms of action therein. Methods High glucose was used to set up a model of β-cell function failure. At the same time, medicated serum of KYQRF with different doses were administered to the cells. Rosiglitazone was taken as a control to observe the changes in insulin secretion, ATP-sensitive K＋ channels （KATP channel） and uncoupling protein-2 （UCP-2） in each group. Results KYQRF had some effects on the insulin secretion. In a low glucose environment, no effective change in insulin secretion was observed （P 〉0.05）. However, insulin levels increased significantly when INS-1 cells were exposed to a high glucose environment （P 〈0.05）. KYQRF could also enhance cell viability （P 〈0.05） in an effect similar to rosiglitazone. Although KYQRF had no effect on inwardly rectifying potassium channels （Kir6.2）（P 〉0.05）, it could decrease the overexpression of both UCP-2 and sulfonylurea receptor 1 （P〈0.05）. Conclusion KYQRF can protect islet function by decreasing UCP-2 and sulfonylurea receptor 1.

关键词： diabetes Kaiyuqingre formula uncoupling protein-2 KATP channel β-cell function

维普期刊数据库

Satellite-assisted 6G wide-area edge intelligence:dynamics-aware task offloading and resource allocation for remote IoT services

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2025年第2期68卷 248-268页

作者： Di zhao Rui DING Bin song State Key Laboratory of Integrated Services Networks Xidian University Hangzhou Institute of Technology Xidian University China Satellite Network Group Co. Ltd.

Future 6G networks will integrate non-terrestrial communication with mobile edge computing to enable wide-area edge intelligence, providing ubiquitous communication and computation services for everyone and everything. In this paper, we introduce the intelligent cloud-edge-device architecture into low Earth orbit(LEO) satellite-supported remote Internet of Things(IoT) networks to facilitate latency-sensitive and compute-intensive IoT applications. However, the dynamic spatio-temporal characteristics inherent in LEO satellite networks, such as the high volatility of task traffic and the high mobility of space nodes, pose severe challenges. For efficient task execution, we investigate the joint optimization of cross-region task offloading and cross-domain resource allocation, and innovatively propose a spatio-temporal attention-based proximal policy optimization(STA-PPO) algorithm. Specifically, the temporal attention-based actor network analyzes the timing dependencies of task arrival and makes time-variant decisions. Simultaneously, the spatial attention-based critic network captures the spatial variations of satellite motion and evaluates the topology-related value. We verify the effectiveness of the cloud-edge-device collaboration through extensive simulations. Numerical results demonstrate that the STA-PPO algorithm outperforms benchmarks, showing the lowest system delay and the highest link throughput.

关键词： 6G wide-area edge intelligence cross-region task offloading cross-domain resource allocation spatio-temporal attention proximal policy optimization

同方期刊数据库

From Static and Dynamic Perspectives:A Survey on Historical Data Benchmarks of Control Performance Monitoring

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2025年第2期12卷 300-316页

作者： Pengyu song Jie Wang Chunhui zhao Biao Huang the State Key Laboratory of Industrial Control Technology College of Control Science and Engineering Zhejiang University IEEE the Department of Chemical and Materials Engineering University of Alberta

In recent decades, control performance monitoring(CPM) has experienced remarkable progress in research and industrial applications. While CPM research has been investigated using various benchmarks, the historical data benchmark(HIS) has garnered the most attention due to its practicality and effectiveness. However, existing CPM reviews usually focus on the theoretical benchmark, and there is a lack of an in-depth review that thoroughly explores HIS-based methods. In this article, a comprehensive overview of HIS-based CPM is provided. First, we provide a novel static-dynamic perspective on data-level manifestations of control performance underlying typical controller capacities including regulation and servo: static and dynamic properties. The static property portrays time-independent variability in system output, and the dynamic property describes temporal behavior driven by closed-loop feedback. Accordingly,existing HIS-based CPM approaches and their intrinsic motivations are classified and analyzed from these two ***, two mainstream solutions for CPM methods are summarized, including static analysis and dynamic analysis,which match data-driven techniques with actual controlling behavior. Furthermore, this paper also points out various opportunities and challenges faced in CPM for modern industry and provides promising directions in the context of artificial intelligence for inspiring future research.

关键词： Control performance monitoring (CPM) data-driven method historical data benchmark (HIS) industrial process performance index static and dynamic analysis

Novel photoresponsive dinuclear nickel catalysts for ethylene (co)polymerization

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2025年第2期68卷 714-722页

作者： Chenlong Nan Tong Pang Jiaxing zhao Lijia Fan Chen Zou Xin-Qi Hao Mao-Ping song jun-Fang Gong Changle Chen Hui Jiang College of Chemistry Pingyuan LaboratoryZhengzhou UniversityZhengzhou 450001China CAS Key Laboratory of Soft Matter Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026China

Compared with the conventional strategies of electronic and/or steric perturbation,catalytic olefin polymerization modulated by light irradiation or metal-metal cooperativity effect is a fascinating challenge that attracts considerable attention in the academic *** this context,we design a strategy that could employ both effects to influence the polymerization *** dinuclear salicylaldimine andα-imino-ketone nickel complexes bearing a stiff-stilbene bridge were prepared,which could transfer between(E)-isomers and(Z)-isomers under ultraviolet *** isomerization can tune the electronic,steric and metal-metal cooperativity effects of the nickel *** this way,the catalytic activity,as well as polymer microstructures including molecular weight and branching density can be modulated in ethylene polymerization and copolymerization *** strategy is generally applicable to other olefin polymerization catalytic systems and other types of transition metal mediated catalysis.

关键词： photoresponsive dinuclear catalyst nickel(II) polar monomer olefin copolymerization

Gradient age-precipitation behavior induced by gradient nano-grain in Mg-Gd-Ag-Zr alloy

维普期刊数据库评论

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 Iron and Steel Research International 2025年第1期32卷 19-24页

作者： Bang-jun Li Jia-peng Sun Jing Han Guo-song Wu College of Materials Science and Engineering Hohai UniversityNanjing 210024JiangsuChina School of Mechanical and Electrical Engineering China University of Mining and TechnologyXuzhou 221116JiangsuChina

Gradient nano-grained structure is frequently engineered into metallic materials,including Mg alloys,to achieve superior combination of strength and ***,the influence of this microstructural feature on aging precipitation behavior remains inadequately *** this study,the age-precipitation behavior of a gradient nano-grained Mg-Gd-Ag-Zr alloy prepared via ultrasonic severe surface rolling was *** result indicates that the aging precipitation behavior exhibits a depth-dependent variation within this *** the nano-grained surface layer,hierarchicalβnano-precipitates are predominant,while at greater depths,the precipitates consist ofβnanoparticles located at grain boundaries,along with intragranularβ′andγ″*** formation ofβnano-precipitates deviates from the conventional precipitation behavior observed in Mg-Gd-Ag alloys,and is attributed to the high density of defects induced by the surface nano-grained *** finding advances our understanding of the precipitation behavior in the alloys with heterogeneous microstructure.

关键词： Mg alloy Gradient Precipitation Aging behavior Microstructure

Data-based neural controls for an unknown continuous-time multi-input system with integral reinforcement

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Control Theory and Technology 2025年第1期23卷 118-130页

作者： Yongfeng Lv jun zhao Wan Zhang Huimin Chang College of Electrical and Power Engineering Taiyuan University of TechnologyTaiyuanShanxi030024China College of Transportation Shandong University of Science and TechnologyQingdao266590ShandongChina School of Mathematical Sciences Shanxi UniversityTaiyuan030006ShanxiChina

Integral reinforcement learning(IRL)is an effective tool for solving optimal control problems of nonlinear systems,and it has been widely utilized in optimal controller design for solving discrete-time ***,solving the Hamilton-Jacobi-Bellman(HJB)equations for nonlinear systems requires precise and complicated ***,the research and application of IRL in continuous-time(CT)systems must be further *** develop the IRL of a CT nonlinear system,a data-based adaptive neural dynamic programming(ANDP)method is proposed to investigate the optimal control problem of uncertain CT multi-input systems such that the knowledge of the dynamics in the HJB equation is ***,the multi-input model is approximated using a neural network(NN),which can be utilized to design an integral reinforcement ***,two criterion networks and one action network are constructed based on the integral reinforcement signal.A nonzero-sum Nash equilibrium can be reached by learning the optimal strategies of the multi-input *** this scheme,the NN weights are constantly updated using an adaptive *** weight convergence and the system stability are analyzed in *** optimal control problem of a multi-input nonlinear CT system is effectively solved using the ANDP scheme,and the results are verified by a simulation study.

关键词： Adaptive dynamic programming Integral reinforcement Neural networks Heuristic dynamic programming Multi-input system