检索结果-南通市图书馆

Needs and challenges of optical atmospheric monitoring on the background of carbon neutrality in 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

Frontiers of Environmental Science & Engineering 2024年第6期18卷 49-62页

作者： Wenqing Liu Chengzhi xing Anhui Institute of Optics and Fine Mechanics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 23001China

The achievement of the targets of coordinated control of PM2.5 and O3 and the carbon peaking and carbon neutrality depend on the development of pollution and greenhouse gas monitoring *** monitoring technology,based on its technical characteristics of high scalability,high sensitivity and wide-targets detection,has obvious advantages in pollution/greenhouse gases monitoring and has become an important direction in the development of environmental monitoring *** present,a system of environmental optical monitoring technology with differential optical absorption spectroscopy(DOAS),cavity ring-down spectroscopy(CRDS),light detection and ranging(LIDAR),laser heterodyne spectroscopy(LHS),tunable diode laser absorption spectroscopy(TDLAS),fourier transform infrared spectroscopy(FTIR)and fluorescence assay by gas expansion(FAGE)as the main body has been ***,with the promotion of“reduction of pollution and carbon emissions”strategy,there have been significant changes in the sources of pollution/greenhouse gases,emission components and emission concentrations,which have put forward new and higher requirements for the development of monitoring *** the future,we should pay more attention to the development of new optical monitoring techniques and the construction of stereoscopic monitoring system,the interdisciplinarity(among mathematics,physics,chemistry and biology,etc.),and the monitoring of greenhouse gases and research on atmospheric chemistry.

关键词： Pollution Greenhouse gas Optical atmospheric monitoring Needs and challenges

Distributed Fault-Tolerant Control of Uncertain Multi-Agent Systems with Connectivity Maintenance

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 & Complexity 2024年第1期37卷 40-62页

作者： xing Xueyan HU Guoqiang Continental-NTU Corporate Lab Nanyang Technological UniversitySingapore 639798Singapore Continental-NTU Corporate Lab and the School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore 639798Singapore

In this paper,a distributed cooperative control protocol is presented to deal with actuator failures of multi-agent systems in the presence of connectivity *** the developed strategy,each agent can track the reference trajectory of the leader in the presence of actuator failures,disturbances and *** connectivity of the multi-agent system can always be ensured during the control *** achieve the aforementioned control objectives,a potential function is introduced to the distributed adaptive fault-tolerant control algorithm to preserve the initial connected network among the *** uncertainty of the multi-agent system,which is allowed to be described by discontinuous functions,is approximated and compensated using the fuzzy logic *** asymptotic stability of the closed-loop system is demonstrated through the use of Cellina’s approximate selection theorem of nonsmooth *** to the developed adaptive laws,the upper bound of the disturbance is allowed to be uncertain,which facilitates the implementation of the control ***,simulation results are provided to verify the effectiveness of the proposed control scheme.

关键词： Actuator failure connectivity maintenance coordination control uncertainties

Reinforcement Learning-Based Dynamic Order Recommendation for On-Demand Food Delivery

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2024年第2期29卷 356-367页

作者： xing Wang Ling Wang Chenxin Dong Hao Ren Ke xing Department of Automation Tsinghua UniversityBeijing 100080China School of Mechanical and Automotive Engineering Qingdao Hengxing University of Science and TechnologyQingdao 266100China Meituan Beijing 100015China

On-demand food delivery(OFD)is gaining more and more popularity in modern *** a kernel order assignment manner in OFD scenario,order recommendation directly influences the delivery efficiency of the platform and the delivery experience of *** paper addresses the dynamism of the order recommendation problem and proposes a reinforcement learning solution *** actor-critic network based on long short term memory(LSTM)unit is designed to deal with the order-grabbing conflict between different ***,three rider sequencing rules are accordingly proposed to match different time steps of the LSTM unit with different *** test the performance of the proposed method,extensive experiments are conducted based on real data from Meituan delivery *** results demonstrate that the proposed reinforcement learning based order recommendation method can significantly increase the number of grabbed orders and reduce the number of order-grabbing conflicts,resulting in better delivery efficiency and experience for the platform and riders.

关键词： on-demand food delivery order recommendation reinforcement learning actor-critic network long short term memory

Dynamic plugging regulating strategy of pipeline robot based on reinforcement learning

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum Science 2024年第1期21卷 597-608页

作者： xing-Yuan Miao Hong Zhao College of Mechanical and Transportation Engineering China University of PetroleumBeijing102249China

Pipeline isolation plugging robot (PIPR) is an important tool in pipeline maintenance operation. During the plugging process, the violent vibration will occur by the flow field, which can cause serious damage to the pipeline and PIPR. In this paper, we propose a dynamic regulating strategy to reduce the plugging-induced vibration by regulating the spoiler angle and plugging velocity. Firstly, the dynamic plugging simulation and experiment are performed to study the flow field changes during dynamic plugging. And the pressure difference is proposed to evaluate the degree of flow field vibration. Secondly, the mathematical models of pressure difference with plugging states and spoiler angles are established based on the extreme learning machine (ELM) optimized by improved sparrow search algorithm (ISSA). Finally, a modified Q-learning algorithm based on simulated annealing is applied to determine the optimal strategy for the spoiler angle and plugging velocity in real time. The results show that the proposed method can reduce the plugging-induced vibration by 19.9% and 32.7% on average, compared with single-regulating methods. This study can effectively ensure the stability of the plugging process.

关键词： Pipeline isolation plugging robot Plugging-induced vibration Dynamic regulating strategy Extreme learning machine Improved sparrow search algorithm Modified Q-learning algorithm

Research on the influences of motion characteristics of jetting projectile charge under water

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第3期33卷 411-425页

作者： xing Chen Yong-gang Lu Institute of Systems Engineering China Academy of Engineering PhysicsMianyang 621900SichuanChina

Shaped charge warhead is important for enhancing the damage performance of underwater *** paper used finite element analysis software and based on JPC water penetration experiments to examine the influence of liner parameters(wall thickness,material),charge aspect ratio,and stand-off distance on the movement characteristics of JPC in *** findings reveal that the head diameter of the JPC increases and experiences significant erosion after entering the water,the effective length of the JPC in water undergoes two distinct phases:a growth phase and a decrease phase,with the velocity of the JPC decaying *** the liner thickness,stand-off distance and the charge aspect ratio can improve the erosion resistance and the velocity retention capacity of the *** optimal ranges for liner thickness and stand-off distance are 0.0363D_(k) to 0.0545D_(k)(D_(k) is the charge diameter),the stand-off distance should be within 1.0D_(k).After the charge aspect ratio higher than 1.25,the charge structure exerts minimal influence the movement characteristics of the JPC in *** density plays a crucial role in the velocity decay pattern of the JPC during *** with higher densities exhibit superior velocity retention capabilities in water,with the velocity decay pattern converging if the densities are ***,copper,tantalum and tungsten liners are deemed appropriate for underwater shaped charge ***,the results will provide an important reference for the design of underwater shaped charge warhead.

关键词： JPC Movement characteristics Underwater penetration Numerical simulation

Adverse Effects of Opioid Analgesics in Osteoarthritis Treatment:A Global Meta-Analysis,2000-2022

在线全文

学校读者我要写书评

暂无评论

China CDC weekly 2024年第25期6卷 589-596,I0001-I0012页

作者： Heng Jiang xing xing He Zhu Tuo Dong School of Public Health Harbin Medical UniversityHarbin CityHeilongjiang ProvinceChina School of Public Health Peking UniversityBeijingChina

Osteoarthritis(OA)treatment commonly depends on nonsteroidal anti-inflammatory drugs and opioid ***,the clinical use of opioids is controversial due to their adverse effects and addiction *** study,drawing on 24 randomized controlled trials(RCTs)with a total of 9,586 patients,thoroughly explored the various side effects associated with opioid use in OA *** results provide additional insight into the non-addictive risks of opioids and may assist clinicians in their judicious use,potentially fostering the advancement of safer treatment *** reducing the risks of misuse and addiction,public health and safety can be enhanced.

关键词： potential thoroughly insight

Stimuli-evoked NOergic molecules and neuropeptides at acupuncture points and the gracile nucleus contribute to signal transduction of propagated sensation along the meridian through the dorsal medulla-thalamic pathways

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 Integrative Medicine 2024年第5期22卷 515-522页

作者： Sheng-xing Ma Lundquist Institute for Biomedical Innovation Harbor-University of California at Los Angeles(UCLA)Medical CenterTorranceCA 90502USA Department of Obstetrics and Gynecology David Geffen School of Medicine at UCLA and Harbor-UCLA Medical CenterTorranceCA 90502USA

Numerous studies from different international groups have demonstrated that sensations can be propagated along acupuncture channel *** propagated sensation along the channel pathway(PSCP)can be elicited by electroacupuncture(EA),transcutaneous electrical nerve stimulation(TENS),manual acupuncture(MA),and heat applied to distal acupuncture points(acupoints).Nitric oxide(NO)levels were reported to be elevated in the gracile nucleus and skin regions near to the EA sites,with higher levels at acupoints associated with an enhanced expression of NO synthase and transient receptor potential vanilloid type *** stimuli,EA,MA,TENS,and heat,have been used to elicit axonal reflexes,which increase local release of NO and neuropeptides such as calcitonin gene related ***,the sensation of PSCP along the body surface occurs only ipsilaterally to the stimulated acupoints in various human studies,which does not support the involvement of the spinal-thalamic pathway,which would involve cross over transmission of the *** gracile nucleus receives ascending input from the sciatic nerve and responds to somatosensory stimulation mainly on the ipsilateral side via the dorsal column *** at Zusanli(ST36)increases NO release and expression of NO synthase mainly in the ipsilateral side of the gracile nucleus,while the cardiovascular effects and analgesic responses to EA at ST36 are changed by influences of l-arginine-derived NO synthesis in the ipsilateral gracile nucleus in *** stimuli-induced release of NOergic molecules and neuropeptides exist high levels in the acupoints,which contain rich neuronal components and blood *** NOergic molecules at acupoints cause axon reflexes during the stimuli,which elevate cutaneous blood *** NOergic molecules and local blood flow may spread over acupoints one after another along the meridian lines differing from nerve pathways following the stimuli to induce *** same types of stimula

关键词： Axon reflex Nitric oxide Biophysical approaches Calcitonin related polypeptide Dorsal funiculus tract Meridian system

Construction of enhanced multi-polarization and high performance electromagnetic wave absorption by self-growing ZnFe_(2)O_(4)on Cu_(9)S_(5)

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1922-1934页

作者： Wenxiong Chen Honglong xing School of Chemical Engineering Anhui University of Science and TechnologyHuainan 232001China

The development of 3D structural composites with electromagnetic(EM)wave absorption could attenuate EM ***,magnetized flower-like Cu_(9)S_(5)/ZnFe_(2)O_(4)composites were fabricated through a multistep hydrothermal *** crystallographic and surface phase chemical information,morphological structure,and magnetic and EM parameters of the composites were *** prepared Cu_(9)S_(5)/ZnFe_(2)O_(4)composites have multiple loss paths for EM waves and present an overall 3D flower-like *** Cu_(9)S_(5)/ZnFe_(2)O_(4)composites exhibit a minimum reflection loss of-54.38 dB and a broad effective absorption bandwidth of 5.92 *** magnetization,ZnFe_(2)O_(4)particles are self-assembled and grown on the surfaces of Cu_(9)S_(5).Such a modification is conducive to the generation of additional cross-linking contact sites and the effective introduction of a large number of phase interfaces,crystalline defects,special three-dimensional flower-like structures,and magneto-electrical coupling loss ***,the synergistic effect of multiple loss strategies effectively improves EM wave absorption by the *** work can provide a strategy for the use of magnetizationmodified sulfide composite functional materials in EM wave absorption.

关键词： self-assembled material electromagnetic wave absorption enhanced multi-polarization effect Cu_(9)S_(5)/ZnFe_(2)O_(4)composites radar cross-section

Discussion on Influencing Factors of Water Resources Environment and Strategies for Protecting Water Ecology

在线全文

学校读者我要写书评

暂无评论

Journal of World Architecture 2024年第5期8卷 36-41页

作者： wangzi Zhou Jing Dong Qianyi Zhao Qianxun Li Changjiang Survey PlanningDesign and Research Co.Ltd.Wuhan 430014China Changjiang River Scientific Research Institute Wuhan 430010China

At present,the major problems facing the water resource environment worldwide include water pollution,water resource shortage,and water ecosystem *** discharge of industrial wastewater,agricultural non-point source pollution,and the discharge of urban sewage lead to a serious decline in water quality,which directly affects the safety of human drinking water and the living environment of aquatic ***,the unbalanced distribution and excessive exploitation of water resources lead to the problem of water shortage in many areas,which then leads to social and economic contradictions and ecological *** terms of ecosystems,the phenomena of water ecological degradation and reduction of biodiversity are increasingly obvious,and the carrying capacity of aquatic ecosystems are gradually *** paper aims to analyze the natural,social,and economic factors affecting the water resource environment,and propose effective strategies to protect the water *** provide a theoretical basis and practical guidance for the sustainable utilization of water resources and the long-term development of the water ecosystem.

关键词： Water resources Environmental impact Water ecology Protection strategy