检索结果-南通市图书馆

Fractional Order Iteration for Gradient Descent Method Based on Event-Triggered Mechanism

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2023年第5期36卷 1927-1948页

作者： lu jiajie WANG Yong FAN yuan Department of Automation University of Science and Technology of ChinaHefei 230026China Anhui Engineering Laboratory of Human-Robot Integration System and Intelligent Equipment School of Electrical Engineering and AutomationAnhui UniversityHefei 230601China

In this work,a novel gradient descent method based on event-triggered strategy has been proposed,which involves integer and fractional order ***,the convergence of integer order iterative optimization method and the stability of its associated system with integrator dynamics are *** on this result,a fractional order iteration approach has been developed by modelling the system with fractional order ***,to reduce the comsumption of computation,a feedback based event-triggered mechanism has been introduced to the gradient descent *** convergence of this new event-triggered optimization algorithm is guaranteed by using a Lyapunov method,and Zeno behavior is proved to be avoided ***,the effectiveness and advantages of the proposed algorithms are verified by numerical simulations.

关键词： Event-triggered mechanism fractional order iteration gradient descent Zeno behavior

Research on Improving the Thermal Conductivity of Epoxy Resin with Flexible Assisted Rigid Groups

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第11期42卷 1845-1854,I0015页

作者： Hong-Yu Zhu Yan-ji Zhu Di Bao lu-Chao Pei Fei Xu Zhe Wang Huai-yuan Wang School of Materials Science and Engineering Tianjin UniversityTianjin300050China Collaborative Innovation Centre of Chemical Science and Engineering(Tianjin) Tianjin UniversityTianjin300072China Tianjin Key Laboratory of Chemical Process Safety and Equipment Technology Tianjin UniversityTianjin300072China School of Chemical Engineering and Technology and State Key Laboratory for Chemical Engineering Tianjin UniversityTianjin300350China

Epoxy resins are cross-linked polymeric materials with typically low thermal ***,the introduction of rigid groups into epoxy resins is the main method to improve their intrinsic thermal *** researchers explored the relationship between the flexible chains of epoxy monomers and the thermal conductivity of the modified epoxy resins(MEP).The effect of flexible chain length on the introduction of rigid groups into the cross-linked structure of epoxy is worth investigating,which is of great significance for the improvement of thermal conductivity of polymers and related *** prepared a small molecule liquid crystal(SMLC)containing a long flexible chain via a simple synthesis reaction,and introduced rigid mesocrystalline units into the epoxy resin via a curing *** high-temperature curing,the introduced mesocrystalline units underwent orientational stacking and were immobilized within the *** and TGA tests showed that the ordering within the modified epoxy resin was increased,which improved the thermal conductivity of the epoxy ***,during the above process,the flexible chains of SMLC provide space for the biphenyl groups to align and therefore affect the thermal conductivity of the ***,the MEP-Ⅵcured with SMLC-Ⅵcontaining six carbon atoms in the flexible chain has the highest thermal conductivity of 0.40W·m^(-1)·K^(-1),which is 125%of the thermal conductivity of SMLC-IV of 0.32 W·m^(-1)·K^(-1),111%of the thermal conductivity of SMLC-Ⅷof 0.36W·m^(-1)·K^(-1),and 182%of the thermal conductivity of pure epoxy of 0.22 W·m^(-1)·K^(-1).The introduction of appropriate length flexible chains for SMLC promotes the stacking of rigid groups within the resin while reducing the occurrence of chain *** study will provide new ideas for the enhancement of thermal conductivity of cross-linked polymeric materials.

关键词： Epoxy Resin Polymer Thermal conductivity Rigid group Flexible chain

Surface reconstruction of heterostructures in alkaline medium towards enhanced electrocatalytic hydrogen evolution

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第6期43卷 2636-2647页

作者： Ming-Yang Yang ji yuan Xue-Lian Fu jing-jing Chen jing Hu Zhou-Guang lu Chen Liu Guangdong Research Center for Interfacial Engineering of Functional Materials Shenzhen Key Laboratory of Polymer Science and TechnologyShenzhen Key Laboratory of Energy Electrocatalytic MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhen 518060China Shenzhen Key Laboratory of Interfacial Science and Engineering of Materials Department of Materials Science and EngineeringSouthern University of Science and TechnologyShenzhen 518055China

Constructing heterostructures has proved to be a successful strategy to fabricate electrocatalysts with high efficiency for water ***,the structure evolution in alkaline hydrogen evolution reaction lacks investigation and the specific active center remains ***,we take the well-designed Ni_(3)S_(2)@VO_(2) heterostructures as a model to investigate the electrocatalytic activity and the surface reconstruction process of heterostructure catalysts in alkaline *** Ni_(3)S_(2)@VO_(2) heterostructures,with Ni_(3)S_(2) nanorods as the core and VO_(2) nanoflakes as the shell,coupled with the high conductive Ni_(3)S_(2),the hydrophilic VO_(2) and modulated electronic structures at the interfaces,exhibited prominent activity and superior stability at various current ***,the ex-situ characterizations confirmed that the surface reconstruction from Ni_(3)S_(2)@VO_(2) into Ni_(3)S_(2)@amorphous-Ni(OH)_(2) in alkaline media could optimize the water dissociation barrier and exposed large active area,thereby contributing to improved electrocatalytic *** study not only introduces novel high-performance electrocatalysts for hydrogen evolution reaction(HER),but also provides a new avenue for re-examining hetero-structural catalysts in alkaline solutions.

关键词： Heterostructures Ni_(3)S_(2)@VO_(2) Surface reconstruction Water dissociation Alkaline hydrogen evolution

Mitigation of greenhouse gases released from mining activities:A review

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2021年第4期28卷 513-521页

作者： Li-yuan Liu Hong-guang ji Xiang-feng Lü Tao Wang Sheng Zhi Feng Pei Dao-lu Quan Beijing Key Laboratory of Urban Underground Space Engineering University of Science and Technology BeijingBeijing 100083China School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China Department of Energy and Mineral Engineering EMS Energy Institute and G3 CenterPennsylvania State UniversityUniversity ParkPA 16802USA

Climate changes that occur as a result of global warming caused by increasing amounts of greenhouse gases(GHGs)released into the atmosphere are an alarming *** greenhouse gas emissions is critically important for the current and future status of mining *** mining industry is one of the significant contributors of greenhouse *** essence,anthropogenic greenhouse gases are emitted directly during the actual mining and indirectly released by the energy-intensive activities associated with mining equipment,ore transport,and the processing ***,we reviewed both direct and indirect GHG emissions to analyze how mining contributes to climate *** addition,we showed how climate change impacts mineral *** assessment was performed using a GHG inventory model for the gases released from mines undergoing different product life *** also elucidate the key issues and various research outcomes to demonstrate how the mining industry and policymakers can mitigate GHG emission from the mining *** review concludes with an overview of GHG release reduction and mitigation strategies.

关键词： greenhouse gas emission greenhouse gas reduction mining climate change life cycle assessment mitigation strategy

Role of refractive index in sum frequency generation intensity of salt solution interfaces

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2015年第12期26卷 1542-1546页

作者： Xia Li Rong-Juan Feng ji-jin Wang Zhen Zhang Zhou lu yuan Guo Beijing National Laboratory for Molecular Sciences State Key Laboratory of Molecular Reaction Dynamics Institute of Chemistry Chinese Academy of Sciences School of Nuclear Science and Technology Lanzhou University

Sum frequency generation spectroscopy（SFG） has been widely used to study the interfacial chemistry of aqueous salt solutions of biological or environmental importance. Most of the SFG data analysis used the same bulk refractive index for different salt concentrations despite of the variations of the refractive indices. Here we systematically investigate the influence of the refractive index on the SFG intensities at various experimental conditions. It is discovered that the SFG intensities are the most sensitive to the refractive index at solid/liquid interfaces nearby the total internal reflection geometries. At air/liquid interfaces, the effect of the refractive indices is also nonegligible. Consequently some important SFG results, such as the response of water structures to the ionic strength at the SiO2/aqueous interfaces, are necessary to be reevaluated. These conclusions on the effect of the small variations of the refractive index are generally useful for the common practice of SFG data analysis.

关键词： refractive interfaces systematically nearby interfacial indices corrected despite incident visible

Nakayama automorphisms of PBW deformations and Hopf actions

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2016年第4期59卷 661-672页

作者： SHEN yuan lu DiMing Department of Mathematics Zhejiang University

Poincaré-Birkhoff-Witt(PBW)deformations of Artin-Schelter regular algebras are skew *** prove that the Nakayama automorphisms of such PBW deformations can be obtained from their *** Calabi-Yau properties are generalized without Koszul *** also show that the Nakayama automorphisms of such PBW deformations control Hopf actions on them.

关键词： Nakayama automorphisms PBW deformations Artin-Schelter regular algebras homogenizations Hopf actions

Innovative dual-mode device integrating capacitive desalination and solar vapor generation for high-efficiency seawater desalination

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2025年第1期 171-179页

作者： jiacheng Wang Zhaoyu Chen Ruduan yuan jiaxin luo Ben Zhang Keju ji Meng Li Juanxiu Xiao Kuan Sun National Innovation Center for Industry-Education Integration of Energy Storage Technology MOE Key Laboratory of Low-grade Energy Utilization Technologies and SystemsCollege of Energy & Power Engineering Chongqing University Xuefeng Mountain Energy Equipment Safety National Observation and Research Station CQU-NUS Renewable Energy Materials & Devices Joint Laboratory Chongqing University Southwest Technology and Engineering Research Institute jiangsu Provincial Key Laboratory of Bionic Functional Materials College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics State Key Laboratory of Marine Resources Utilization in South China Sea Collaborative Innovation Center of Marine Science and Technology School of Marine Science and Engineering Hainan University

Solar-driven interface evaporation with high solar-to-steam conversion efficiency has shown great potential in seawater ***,due to the influence of latent heat and condensation efficiency,the water yield from solar-driven interface evaporation remains insufficient,posing a significant challenge that requires *** this work,we designed a dual-mode high-flux seawater desalination device that combines solar-driven interface evaporation and capacitive *** utilizing coupled desalination materials exhibiting both photothermal conversion and capacitance activity,the device demonstrated photothermal evaporation rates of 1.41 and 0.97 kg m-2h-1for condensate water yield under one-sun ***,the device exhibited a salt adsorption capacity of up to48 mg g-1and a salt adsorption rate of 2.1 mg *** addition,the salt adsorption capacity increased by approximately 32% under one-sun ***,photo-enhanced capacitive desalination performance was explored through numerical simulations and theoretical *** calculations and characterizations confirmed that the defect energy levels formed by the introduction of sulfur vacancies can effectively widen the light absorption range,improve photothermal conversion performance,and stimulate more photoelectrons to participate in capacitive ***,the electron distribution state of molybdenum disulfide with sulfur vacancies and surface defect sites contributes to ion/electron transport at the solid-liquid *** work provides a novel pathway for integrating solar vapor generation with other low-energy desalination technologies.

关键词：

An Adaptive Regulation Problem and Its Application

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Automation and computing 2017年第2期14卷 221-228页

作者： yuan jiang ji-Yang Dai Key Laboratory of Image Processing and Pattern Recognition Nanchang Hangkong University Nanchang 330063 China School of Information Engineering Nanchang Hangkong University Nanchang 330063 China

This paper studies an adaptive regulation problem for the modified FitzHugh-Nagumo neuron model under external electrical stimulation. We first present the solution of the global robust output regulation problem for output feedback system with an uncertain exosystem which models the external electrical stimulation with unknown frequency and amplitude. Then, we show that the robust control problem for the modified FitzHugh-Nagumo neuron model can be formulated as the global robust output regulation problem and the solvability conditions for the output regulation problem for the modified FitzHugh-Nagumo neuron model are all satisfied. Then, we apply the obtained output regulation result to constructing an output feedback control law for the modified FitzHugh-Nagumo neuron model to achieve global stability of the closed-loop system in the presence of uncertain parameters and external stimulus. An example is given to show that the proposed algorithm can completely reject the external electrical stimulation.

关键词： Control theory Lyapunov methods internal model principle modified FitzHugh-Nagumo model.

Robustness of critical points in a complex adaptive system： Effects of hedge behavior

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2013年第4期8卷 461-466页

作者： yuan Liang ji-Ping Huang Department of Physics and State Key Laboratory of Surface Physics Fudan University Shanghai 200433 China Department of Physics College of Science Donghua University Shanghai 201602 China

In our recent papers, we have identified a class of phase transitions in the market-directed resource- allocation game, and found that there exists a critical point at which the phase transitions occur. The critical point is given by a certain resource ratio. Here, by performing computer simulations and theoretical analysis, we report that the critical point is robust against various kinds of human hedge behavior where the numbers of herds and contrarians can be varied widely. This means that the critical point can be independent of the total number of participants composed of normal agents, herds and contrarians, under some conditions. This finding means that the critical points we identified in this complex adaptive system （with adaptive agents） may also be an intensive quantity, similar to those revealed in traditional physical systems （with non-adaptive units）.

关键词： complex adaptive system phase transition resource allocation hedge behavior agent-based simulation