检索结果-南通市图书馆

IEEE/CAA Journal of Automatica Sinica 2023年第2期10卷 572-574页

作者： Zhengqing Han Yintao Wang Qi Sun the School of Marine Science and Technology Northwestern Polytechnical UniversityXi’an 710072China

Dear Editor,This letter presents a distributed deep reinforcement learning(DRL) based approach to deal with the path following and formation control problems for underactuated unmanned surface vehicles(USVs). By constructing two independent actor-critic architectures,the deep deterministic policy gradient(DDPG) method is proposed to determine the desired heading and speed command for each USV.

关键词： Deep policy heading

Event-triggered robust MPC of nonlinear cyber-physical systems against DoS attacks

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2022年第1期65卷 22-38页

作者： Qi Sun Jicheng CHEN Yang SHI Department of Mechanical Engineering University of Victoria

This paper proposes an event-triggered robust nonlinear model predictive control(NMPC) framework for cyber-physical systems(CPS) in the presence of denial-of-service(Do S) attacks and additive disturbances. In the framework, a new robustness constraint is introduced to the NMPC optimization problem in order to deal with additive disturbances, and a packet transmission strategy is designed for NMPC such that Do S attacks can be tackled. Then, an event-triggered mechanism, which accommodates Do S attacks occurring in the communication network, is proposed to reduce the communication cost for resource-constrained CPSs. Besides, we prove that the NMPC algorithm is recursively feasible and the closed-loop system is input-to-state practical stable under some sufficient conditions. Simulation examples and comparisons are conducted to show the effectiveness of the proposed NMPC algorithm.

关键词： cyber-physical systems nonlinear model predictive control event-triggered mechanism robust control denial-of-service attacks

Recent progress on sulfide infrared nonlinear optical materials with large SHG response and wide band gap

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2023年第1期42卷 22-29页

作者： Linan Wang Qi Sun Junjie Li Research Center for Crystal Materials CAS Key Laboratory of Functional Materials and Devices for Special EnvironmentsXinjiang Technical Institute of Physics&ChemistryCASUrumqi830011China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing100049China

As the core device of all-solid-state laser,infrared(IR)nonlinear optical(NLO)material plays a critical role in exploring new coherent lights by frequency conversion technologies,which are widely used in noninvasive medical diagnostics,spectroscopy,environmental monitoring and long-distance laser communication.To satisfy the growing demand of current laser technology in IR regions,high performance NLO materials with large second-harmonic generation(SHG)response,high laser-induced damage threshold(LIDT)and wide transparency range are highly expected.Recently,numerous efforts and advances have been achieved in sulfide system.This review highlights the progress of high-performance sulfide IR NLO materials with a good balance between strong SHG response(≥1.0×AgGaS_(2))and wide band gap(≥3.0 eV)since 2018.The chemical synthesis,crystal structure,optical properties and structure-property relationship of 13 high performance metal sulfide IR NLO materials are summarized and reviewed in detail.Finally,the potential opportunities and challenges in IR NLO materials are discussed.

关键词： Infrared NLO material s Sulfide Structure-property relationship Optical property

Lower deviations for supercritical branching processes with immigration

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Mathematics in China 2021年第2期16卷 567-594页

作者： Qi Sun Mei ZHANG School of Mathematics and Statistics Beijing Technology and Business UniversityBeijing 100048China School of Mathematical Sciences Laboratory of Mathematics and Complex SystemsBeijing Normal UniversityBeijing 100875China

For a supercritical branching processes with immigration {Zn};it is known that under suitable conditions on the offspring and immigration distributions, Zn/mn converges almost surely to a finite and strictly positive limit, where m is the offspring mean. We are interested in the limiting properties of P(Zn=kn) with kn=o(mn) as n→∞. We give asymptotic behavior of such lower deviation probabilities in both Schröder and Böttcher cases, unifying and extending the previous results for Galton-Watson processes in literature.

关键词： Supercritical branching processes lower deviations immigration

Occupancy of rooms in urban residential buildings by users in cold areas of China

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Building Simulation 2023年第3期16卷 483-497页

作者： qi Dong Zikai Ma Cheng sun School of Architecture Harbin Institute of TechnologyHarbin 150006China Key Laboratory of Cold Region Urban and Rural Human Settlement Environment Science and Technology Ministry of Industry and Information TechnologyHarbin 150006China

Occupancy is used to represent the movements and locations of users among various zones of buildings,and it is the basis of all other daily energy consumption behaviors.This study investigated eight families in cold areas of China based on occupancy measurements obtained in four main rooms,i.e.,living room,bedroom,kitchen,and bathroom.In particular,we analyzed the duration of user occupancy and hourly mean occupancy,and characterized their regular and random features.According to the results,we developed an event-based occupancy model using an inhomogeneous Markov chain,where the rooms were modeled and daily events were divided into three categories according to their randomness.We established a new method for conversion between event characteristic parameters and a transition probability matrix,as well as an overlap avoidance method for active events.The model was then validated using real data.The results showed that the model performed well in terms of two evaluation criteria.The model should improve the accuracy of simulations of occupancy.

关键词： event occupancy urban residential building simulation cold areas of China

Porous Polymeric Catalysts Constructed from Vinylated Functionalities

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Accounts of Materials Research 2022年第7期3卷 772-781页

作者： Qi Sun Feng-Shou Xiao Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 310027China

CONSPECTUS:Porous organic polymers(POPs)have revolutionized the production of advanced catalytic materials with unique features such as a large surface area,tunable pore structure,ease of functionalization with a wide range of functional groups,and the ability to function as hosts for encapsulation of functional species,making them appealing for task-specific applications.Although numerous POP-based catalysts have been developed,they are rarely used as a common tool for preparatory-scale operations in laboratories.

关键词： Porous operations Polymeric

The cathode catalysts of hydrogen fuel cell:From laboratory toward practical application

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2023年第4期16卷 4365-4380页

作者： Shuang Cao Tong sun Jin-Rong Li qin-Zhu Li Chun-Chao Hou Qi Sun College of Chemistry and Chemical Engineering Institute for Sustainable Energy and ResourcesQingdao UniversityQingdao 266071China School of Materials Science and Engineering Ocean University of ChinaQingdao 266100China

Proton exchange membrane fuel cells(PEMFCs)have received a sustained world-wide attention owing to their promising applications based on clean energy.However,their widespread applications are still restricted by the sluggish oxygen reduction reaction(ORR)process.Over the past decades,significant efforts have been devoted to developing efficient ORR catalysts,which have been summarized in numerous previous reviews.Unfortunately,most of them mainly focused on ORR activity on the rotating disk electrode(RDE)level,which cannot truly represent the performance in real applications.Developing and showcasing efficient catalysts evaluated at the membrane electrode assembly(MEA)level is of vital importance.In this review,we first briefly showcased the recent development of ORR catalysts and then put more emphasis on the discussion of designing efficient catalysts at MEA and full-cell level,aiming to help stimulate more attention on their practical applications.

关键词： oxygen reduction reaction hydrogen energy membrane electrode assembly proton exchange membrane fuel cells

Enhanced hydrolytic removal of tylosin in wastewater using polymer-based solid acid catalysts converted from polystyrene

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 Environmental Sciences 2023年第4期126卷 287-296页

作者： Shiling Li Shuhan sun Fei qi Xiaomin Dou Beijing Key Lab for Source Control Technology of Water Pollution College of Environmental Science and EngineeringBeijing Forestry UniversityBeijing 100083China Engineering Research Center for Water Pollution Source Control and Eco-remediation College of Environmental Science and EngineeringBeijing Forestry UniversityBeijing 100083China

Antibiotic production wastewater usually contains high concentrations of antibiotic residues,which can cause instability and deterioration of biological wastewater treatment units and also domestication and proliferation of antibiotic-resistance bacteria.An effective pretreatment on antibiotics production wastewater is expected to selectively reduce the concentration of antibiotics and decrease the toxicity,rather than mitigate organic and other contaminants before further treatments.In this work,two polymer-based solid acids,PS-S and CPS-S bearing high concentrations of-SOH_(3)groups (up to 4.57 mmol/g),were prepared and successfully used for hydrolytic mitigation of 100 mg/L tylosin within 20 min.The co-existence of high concentrations of COD and humic substances did not affect the mitigation of tylosin obviously,while more than 500 mg/L of nitrogenous compounds suppressed the hydrolytic efficiency.Recycle and reuse experiments showed that the solid acids performed well in five cycles after regeneration.Three transformation products (P1,P2 and P3)were identified using UPLC-QTOF-MS/MS.Sugar moieties including mycarse,mycaminose,and mycinose detached and released simultaneously or in order from the 16-member lactone ring through desugarization,which led to a dramatic decrease in antibacterial activity as revealed by cytotoxicity evaluations using S.aureus.Ecotoxicity estimation indicated the acute toxicities of the hydrolyzed products to model species (e.g.,fish,daphnid and green algae) were classified as“not harmful”.This work suggested an effective and selective method to pretreat tylosin-contained production wastewater by using polymer-based solid acids.These results will shed light on effective elimination of antibiotics pollution from pharmaceutical industries through strengthening the pretreatments.

关键词： Polymer Sulfonation Solid acid catalysts Tylosin hydrolysis Antibiotic

Preparation of CF/Ni-Fe/CNT/silicone layered rubber for aircraft sealing and electromagnetic interference shielding applications

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2021年第10期34卷 91-102页

作者： Wanying LUAN qin WANG Qi Sun Yinxiang LU Department of Materials Science Fudan UniversityShanghai 200433China

To meet the needs of preventing information leakage in space engineering and military industry,an efficient method was introduced to obtain layered electromagnetic shielding sealing rubber.The carbon fiber,Ni-Fe coating,and Carbon Nano Tube(CNT)were combined by chemical plating and in-situ polymerization to obtain a lightweight(0.14 g/cm^(2))and thin(1 mm thick)Carbon fiber Fabric(CF)/Ni-Fe/CNT/silicone layered electromagnetic shielding composites.The layered material obtained by adjusting the electroless plating time exhibited a high Shielding Efficiency(SE)of 60.2–85.5 d B in the range of 0–4800 MHz,which can be used for aviation electromagnetic shielding.Carbon fibers and carbon nanotubes mainly attenuated electromagnetic waves through absorption loss,while the nickel-iron alloy coating through reflection loss interacted with the magnetic vector of incident Electro Magnetic(EM)radiation and magnetic dipoles,therefore,the EM Interference(EMI)shielding composite attenuated EM waves with the“absorptionreflection-absorption”cooperative interaction.Moreover,the flexible fabric substrate adhered with silicone rubber possessed a breaking elongation of 52.3%,which can be utilized as a good sealing material.Simultaneously,the outstanding exothermicity(67.2℃ under the applied voltage of 5 V)makes it possible to be applied in electric heating area.The electromagnetic shielding composites prepared in this paper have good potential in the fields of precision electronic equipment and aviation systems.

关键词： Electroless plating Electromagnetic interference shielding Heating effects Nickel-iron(Ni-Fe)coating Sealing rubber

Effects of natural organic matter on cadmium mobility in paddy soil: A review

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2021年第6期33卷 204-215页

作者： Chaolei Yuan qi Li Zhaoyang sun Hongwen sun Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria Tianjin Key Laboratory of Environmental Remediation and Pollution ControlCollege of Environmental Science and EngineeringNankai UniversityTianjin 300350China

Cadmium(Cd) contamination in paddy soil has caused public concern. The uptake of Cd by rice plants depends on soil Cd mobility, which is in turn substantially influenced by organic matter(OM). In this review, we first summarize the fate of Cd in soil and the role of OM. We then focus on the effects of OM on Cd mobility in paddy soil and the factors influencing the remedial effectiveness of OM amendments. We further discuss the performance of straw incorporation in the remediation of Cd-contaminated paddy soils reported in laboratory and field studies. Considering the huge production of organic materials(such as straw) in agriculture, the use of natural OM for soil remediation has obvious appeal due to the environmental benefits and low cost. Although there have been successful application cases, the properties of OM amendments and soil can significantly affect the remedial performance of the OM amendments. Importantly, straw incorporation alone does not often decrease the mobility of Cd in soil or the Cd content in rice grains. Careful evaluation is required when considering natural OM amendments, and the factors and mechanisms that influence their remedial effectiveness need further investigation in paddy soil with realistic Cd concentrations.

关键词： Cadmium Mobility Organic matter Paddy soil Remediation