检索结果-南通市图书馆

Asymmetric two-dimensional diffraction grating via a vortex field in an inverted-Ytype atomic system

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2024年第5期76卷 77-85页

作者： Duo Zhang ke Wang Kunpeng Zhao Mei Wang Zhaoyu Sun School of Electrical and Electronic Engineering Wuhan Polytechnic UniversityWuhan 430023China

We propose a theoretical scheme to realize a two-dimensional(2.)diffraction grating in a four-level inverted-Y-type atomic system coupled by a standing-wave(SW)field and a Laguerre-Gaussian(LG)vortex *** to asymmetric spatial modulation of the LG vortex field,the incident probe field can be lopsidedly diffracted into four domains and an asymmetric 2. electromagnetically induced grating is *** adjusting the detunings of the probe field and the LG vortex field,the intensities of the LG vortex field and the coherent SW field,as well as the interaction length,the diffraction properties and efficiency,can be effectively *** addition,the effect of the azimuthal parameter on the Fraunhofer diffraction of the probe field is also *** asymmetric 2. diffraction grating scheme may provide a versatile platform for designing quantum devices that require asymmetric light transmission.

关键词： asymmetric diffraction grating standing-wave field Laguerre-Gaussian vortex field diffraction property

Visible and selective gel assembly via covalent click chemistry

在线全文

学校读者我要写书评

暂无评论

SmartMat 2024年第2期5卷 137-144页

作者： Yinglin Zheng Zhihai ke School of Science and Engineering The Chinese University of Hong KongShenzhenChina

This study marks the birth of visible and selective click covalent *** is achieved by amplifying orthogonal alkyne−azide click chemistry through interfacial multisite interactions between azide/alkyne functionalized polymer *** assembly of hydrogels via host−guest chemistry or noncovalent interactions such as electrostatic interactions has been *** macroscopic supramolecular assembly,here we report visible and selective“click”covalent assembly of hydrogels at the ***-like hydrogels modified with alkyne and azide groups,respectively,can click together via the formation of covalent *** concentration-dependent assembly and selective covalent assembly have been ***,macroscopic gel assembly clearly elucidates click preferences and component selectivity not observed in the solution reactions of competing monomers.

关键词： click chemistry hydrogel selective covalent assembly

Projecting Wintertime Newly Formed Arctic Sea Ice through Weighting CMIP6 Model Performance and Independence

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2024年第8期41卷 1465-1482页

作者： Jiazhen ZHAO Shengping HE ke FAN Huijun WANG Fei LI key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)Nanjing University of Information Science&TechnologyNanjing 210044China Geophysical Institute University of Bergen and Bjerknes Centre for Climate ResearchBergen 5007Norway School of Atmospheric Science Sun Yat-sen Universityand Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China Nansen Environmental and Remote Sensing Center and Bjerknes Centre for Climate Research Bergen 5007Norway Nansen-Zhu International Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519082China

Precipitous Arctic sea-ice decline and the corresponding increase in Arctic open-water areas in summer months give more space for sea-ice growth in the subsequent cold seasons. Compared to the decline of the entire Arctic multiyear sea ice,changes in newly formed sea ice indicate more thermodynamic and dynamic information on Arctic atmosphere–ocean–ice interaction and northern mid–high latitude atmospheric teleconnections. Here, we use a large multimodel ensemble from phase 6 of the Coupled Model Intercomparison Project(CMIP6) to investigate future changes in wintertime newly formed Arctic sea ice. The commonly used model-democracy approach that gives equal weight to each model essentially assumes that all models are independent and equally plausible, which contradicts with the fact that there are large interdependencies in the ensemble and discrepancies in models' performances in reproducing observations. Therefore, instead of using the arithmetic mean of well-performing models or all available models for projections like in previous studies, we employ a newly developed model weighting scheme that weights all models in the ensemble with consideration of their performance and independence to provide more reliable projections. Model democracy leads to evident bias and large intermodel spread in CMIP6 projections of newly formed Arctic sea ice. However, we show that both the bias and the intermodel spread can be effectively reduced by the weighting scheme. Projections from the weighted models indicate that wintertime newly formed Arctic sea ice is likely to increase dramatically until the middle of this century regardless of the emissions ***, it may decrease(or remain stable) if the Arctic warming crosses a threshold(or is extensively constrained).

关键词： wintertime newly formed Arctic sea ice model democracy model weighting scheme model performance model independence

Exercise-induced adaptation of neurons in the vertebrate locomotor system

在线全文

学校读者我要写书评

暂无评论

Journal of Sport and Health Science 2024年第2期13卷 160-171页

作者： Yue Dai Yi Cheng Renkai Ge ke Chen Liming Yang key Lab of Adolescent Health Assessment and Exercise Intervention of Ministry of Education College of Physical Education and Health CareEast China Normal UniversityShanghai 200241China Shanghai key Laboratory of Multidimensional Information Processing School of Communication and Electronic EngineeringEast China Normal UniversityShanghai 200241China School of Physical Education and Health Care East China Jiaotong UniversityNanchang 330013China key Laboratory of High Confidence Software Technologies of Ministry of Education School of Computer SciencePeking UniversityBeijing 100871China

Vertebrate neurons are highly dynamic cells that undergo several alterations in their functioning and physiologies in adaptation to various external *** particular,how these neurons respond to physical exercise has long been an area of active *** of the vertebrate locomotor system’s adaptability suggest multiple mechanisms are involved in the regulation of neuronal activity and properties during *** this brief review,we highlight recent results and insights from the field with a focus on the following mechanisms:(a)alterations in neuronal excitability during acute exercise;(b)alterations in neuronal excitability after chronic exercise;(c)exercise-induced changes in neuronal membrane properties via modulation of ion channel activity;(d)exercise-enhanced dendritic plasticity;and(e)exercise-induced alterations in neuronal gene expression and protein *** hope is to update the community with a cellular and molecular understanding of the recent mechanisms underlying the adaptability of the vertebrate locomotor system in response to both acute and chronic physical exercise.

关键词： Dendritic plasticity Excitability Exercise Ion channel modulation Neuron adaptation

Driver at 10 MJ and 1 shot/30 min for inertial confinement fusion at high gain:Efficient,compact,low-cost,low laser-plasma instabilities,beam color selectable from 2./3ω/4ω,applicable to multiple laser fusion schemes

在线全文

学校读者我要写书评

暂无评论

Matter and Radiation at Extremes 2024年第4期9卷 4-7页

作者：隋展蓝可 Shanghai Institute of Laser Plasma China Academy of Engineering PhysicsShanghai 201800China Instituteof Applied Physics and Computational Mathematics Beijing 100094China

The achievement of ignition at the National Ignition Facility(NIF)has prompted a global wave of further research on inertial fusion energy(IFE).However,IFE requires a target gain G of 30-100,and it is hard to achieve fusion at such high gain with the energy,configuration,and technical approach of the ***,we present a conceptual design for a next-generation laser driver that is applicable to multiple laser fusion schemes and provides 10 MJ,2.3 PW at 3ω(or 2.,in which case the energy and power can be higher),and one shot per 30 min,with the aim of achieving G>*** is also efficient,compact,and low in cost,and it has low susceptibility to laser-plasma instabilities.

关键词： applicable compact instabilities

Sustainable management of campus fallen leaves through low-temperature pyrolysis and application in Pb immobilization

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 2024年第5期139卷 281-292页

作者： Rongli Tan ke Li Yue Sun Xiaoliang Fan Zhengtao Shen Lingyi Tang School of Environment Nanjing UniversityNanjing 210023China School of Chemistry and Chemical Engineering Nanjing UniversityNanjing 210023China School of Earth and Engineering Sciences Nanjing UniversityNanjing 210023China Department of Earth and Atmospheric Sciences University of AlbertaEdmonton T6G 2E3Canada

Realizing campus sustainability requires the environmental-friendly and economical treatment of tremendous fallen *** fallen leaf biochar at a low temperature is a candidate *** this study,six common types of fallen leaves on the campus were pyrolyzed at 300℃.The obtained biochars were characterized and the adsorption mechanisms of lead(Pb)by the fallen leaf biochars were *** adsorption capacity of leaf biochar for Pb was relatively high,up to 2.9 mg/g(Yulania denudata leaf biochar).Adsorption of Pb onto active sites was the rate-limiting step for most leaf *** for Platanus leaf biochar,intraparticle diffusion of Pb^(2.)dominated owing to the lowest adsorption ***,the highest exchangeable Pb fraction(2.%)indicated its potential for removing aqueous Pb^(2.).Ginkgo and Prunus cerasifera leaf biochar immobilized Pb by surface complexation and precipitation as lead ***,they were suitable for soil heavy metal *** study shed the light on the sustainable utilization of campus fallen leaves and the application of fallen leaf biochars in heavy metal remediation.

关键词： Fallen leaves Waste management Biochar Lead removal Sorption Circular campus

Optimization of Fixture Number in Large Thin-Walled Parts Assembly Based on IPSO

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2024年第2期37卷 213-227页

作者： Changhui Liu Jing Wang Ying Zheng ke Jin Jianbo Yu Jianfeng Liu School of Mechanical Engineering Tongji UniversityShanghai 201804China Shanghai Jiaotong University Shanghai 200240China Shanghai Waigaoqiao Shipbuilding Co. Ltd.Shanghai 200137China

There are lots of researches on fixture layout optimization for large thin-walled *** researches focus on the positioning problem,i.e.,optimizing the positions of a constant number of ***,how to determine the number of fixtures is *** most cases,the number of fixtures located on large thin-walled parts is determined based on engineering experience,which leads to huge fixture number and extra ***,this paper constructs an optimization model to minimize the number of *** constraints are set in the optimization model to ensure that the part deformation is within the surface profile *** addition,the assembly gap between two parts is also *** conduct the optimization,this paper develops an improved particle swarm optimization(IPSO)algorithm by integrating the shrinkage factor and adaptive inertia *** the algorithm,particles are encoded according to the fixture *** dimension of the particle is assigned to a sub-region by constraining the optional position range of each fixture to improve the optimization ***,a case study on ship curved panel assembly is provided to prove that our method can optimize the number of fixtures while meeting the assembly quality *** research proposes a method to optimize the number of fixtures,which can reduce the number of fixtures and achieve deformation control at the same time.

关键词： Assembly quality Large thin-walled parts Fixture layout PSO FEM

Adaptive Trajectory Tracking Control for Nonholonomic Wheeled Mobile Robots:A Barrier Function Sliding Mode Approach

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 1007-1021页

作者： Yunjun Zheng Jinchuan Zheng ke Shao Han Zhao Hao Xie Hai Wang the School of Mechanical Engineering Hefei University of TechnologyHefei 230009China the School of Science Computing and Engineering TechnologiesSwinburne University of TechnologyHawthorn VIC 3122Australia the School of Civil Aviation Northwestern Polytechnical UniversityXi’an 710072China the Shanghai Aerospace Control Technology Institute Shanghai 201109 the School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China the College of Science HealthEngineering and EducationMurdoch UniversityPerth WA6150Australia

The trajectory tracking control performance of nonholonomic wheeled mobile robots(NWMRs)is subject to nonholonomic constraints,system uncertainties,and external *** paper proposes a barrier function-based adaptive sliding mode control(BFASMC)method to provide high-precision,fast-response performance and robustness for *** with the conventional adaptive sliding mode control,the proposed control strategy can guarantee that the sliding mode variables converge to a predefined neighborhood of origin with a predefined reaching time independent of the prior knowledge of the uncertainties and disturbances *** advantage of the proposed algorithm is that the control gains can be adaptively adjusted to follow the disturbances amplitudes thanks to the barrier *** benefit is that the overestimation of control gain can be eliminated,resulting in chattering ***,a modified barrier function-like control gain is employed to prevent the input saturation problem due to the physical limit of the *** stability analysis and comparative experiments demonstrate that the proposed BFASMC can ensure the prespecified convergence performance of the NWMR system output variables and strong robustness against uncertainties/disturbances.

关键词： Adaptive sliding mode barrier function nonholonomic wheeled mobile robot(NWMR) trajectory tracking control

Behaviour recognition based on the integration of multigranular motion features in the Internet of Things

在线全文

学校读者我要写书评

暂无评论

Digital Communications and Networks 2024年第3期10卷 666-675页

作者： Lizong Zhang Yiming Wang ke Yan Yi Su Nawaf Alharbe Shuxin Feng School of Computer Science and Engineering University of Electronic Science and Technology of ChinaChengdu611731China Beijing Institute of Remote Sensing Equipment Beijing100039China Applied College Taibah UniversityMedina42353Saudi Arabia

With the adoption of cutting-edge communication technologies such as 5G/6G systems and the extensive development of devices,crowdsensing systems in the Internet of Things(IoT)are now conducting complicated video analysis tasks such as behaviour *** applications have dramatically increased the diversity of IoT ***,behaviour recognition in videos usually requires a combinatorial analysis of the spatial information about objects and information about their dynamic actions in the temporal *** recognition may even rely more on the modeling of temporal information containing short-range and long-range motions,in contrast to computer vision tasks involving images that focus on understanding spatial ***,current solutions fail to jointly and comprehensively analyse short-range motions between adjacent frames and long-range temporal aggregations at large scales in *** this paper,we propose a novel behaviour recognition method based on the integration of multigranular(IMG)motion features,which can provide support for deploying video analysis in multimedia IoT crowdsensing *** particular,we achieve reliable motion information modeling by integrating a channel attention-based short-term motion feature enhancement module(CSEM)and a cascaded long-term motion feature integration module(CLIM).We evaluate our model on several action recognition benchmarks,such as HMDB51,Something-Something and *** experimental results demonstrate that our approach outperforms the previous state-of-the-art methods,which confirms its effective-ness and efficiency.

关键词： Behaviour recognition Motion features Attention mechanism Internet of things Crowdsensing