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Particle size distribution and characteristics of heavy metals in road-deposited sediments from Beijing Olympic Park

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Journal of Environmental Sciences 2015年第6期27卷 228-237页

作者： Haiyan Li anbang shi Xiaoran Zhang Key Lab of Urban Storm-Water System and Water Environment Beijing University of Civil Engineering and Architecture

Due to rapid urbanization and industrialization, heavy metals in road-deposited sediments（RDSs） of parks are emitted into the terrestrial, atmospheric, and water environment, and have a severe impact on residents＇ and tourists＇ health. To identify the distribution and characteristic of heavy metals in RDS and to assess the road environmental quality in Chinese parks, samples were collected from Beijing Olympic Park in the present study. The results indicated that particles with small grain size（〈150 μm） were the dominant fraction. The length of dry period was one of the main factors affecting the particle size distribution, as indicated by the variation of size fraction with the increase of dry days. The amount of heavy metal（i.e., Cu, Zn, Pb and Cd） content was the largest in particles with small size（〈150 μm） among all samples. Specifically, the percentage of Cu, Zn, Pb and Cd in these particles was 74.7%, 55.5%, 56.6% and 71.3%, *** metals adsorbed in sediments may mainly be contributed by road traffic emissions. The contamination levels of Pb and Cd were higher than Cu and Zn on the basis of the mean heavy metal contents. Specifically, the geoaccumulation index（I geo） decreased in the order：Cd〉Pb〉Cu〉Zn. This study analyzed the mobility of heavy metals in sediments using partial sequential extraction with the Tessier procedure. The results revealed that the apparent mobility and potential metal bioavailability of heavy metals in the sediments, based on the exchangeable and carbonate fractions, decreased in the order： Cd〉Zn≈Pb〉Cu.

关键词： Size distribution Characteristics Heavy metals Road-deposited sediments Contamination assessment Beijing Olympic Park

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城市地表颗粒物重金属分布特征及其影响因素分析

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生态环境学报 2014年第11期23卷 1852-1860页

作者：李海燕石安邦北京市可持续城市排水系统构建与风险控制工程技术研究中心北京100044

城市地表颗粒物作为重金属的重要载体,严重危害城市人群和水体,已成为城市环境的重要研究对象。阐述了对地表颗粒物重金属的空间、粒径、赋存形态等分布特征及其影响因素进行系统分析的意义。通过对国内不同城市不同功能区的重金属(主要... 详细信息

城市地表颗粒物作为重金属的重要载体,严重危害城市人群和水体,已成为城市环境的重要研究对象。阐述了对地表颗粒物重金属的空间、粒径、赋存形态等分布特征及其影响因素进行系统分析的意义。通过对国内不同城市不同功能区的重金属(主要为:Zn、Cu、Cd、Pb)数据进行对比分析,各功能区重金属污染情况为:Cu、Pb:工业区>商业区>交通区>居民区>休闲区;Zn:工业区>交通区>商业区>居民区>休闲区;Cd:交通区>工业区>商业区>居民区>休闲区,同时各功能区中Zn、Pb含量波动性较大。整体上国内工业区、交通区和商业区地表颗粒物重金属污染严重。与我国的土壤重金属背景值相比,4种金属中Cd污染程度最为严重。探讨了与国外部分城市地表颗粒重金属污染特征之间的差异,指出国内城市重金属含量均值整体上低于欧美发达城市,而国内一线城市重金属含量明显偏高。系统分析了颗粒物重金属的粒级效应,赋存形态以及生物有效性。综述了城市交通活动(主要为交通流量、车辆行驶速度、变速频率、车辆类型、道路特征等)、降雨冲刷事件、雨前干燥期、大气风力作用、和其他因素对地表颗粒物重金属分布特征的影响。某种程度上,道路车辆的行驶速度和变速对颗粒物重金属累积的影响作用大于交通流量。不同降雨事件和雨前干燥期对重金属分布特征影响的研究结论不一,但地表颗粒对大气PM2.5重金属贡献较大。今后应在以下方面进一步加强对城市地表颗粒物重金属的研究:建立颗粒物粒径划分标准;加强重金属在降雨冲刷过程变化规律的分析;探讨地表颗粒物与大气颗粒物重金属转换关系;还应开展中小型城市,城乡结合部(城中村)地表颗粒物重金属污染特性研究。

关键词：地表颗粒物重金属分布特征粒级效应赋存形态影响因素

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结合电流应力优化与虚拟电压补偿的双有源桥DC-DC变换器三重移相优化控制

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电工技术学报 2022年第10期37卷 2559-2571页

作者：蔡逢煌石安邦江加辉王武林琼斌福州大学电气工程与自动化学院福州350108 青岛大学电气工程学院青岛266071

为了同时减小双有源桥(DAB)DC-DC变换器的电流应力和提高动态响应速度,该文在建立三重移相下六种模式的传输功率、电流应力等工作特性模型的基础上,提出一种基于三重移相的结合电流应力优化与虚拟电压补偿的控制方法。该方法由电流应力... 详细信息

为了同时减小双有源桥(DAB)DC-DC变换器的电流应力和提高动态响应速度,该文在建立三重移相下六种模式的传输功率、电流应力等工作特性模型的基础上,提出一种基于三重移相的结合电流应力优化与虚拟电压补偿的控制方法。该方法由电流应力最优移相角模型和虚拟电压补偿方法构成,通过KKT条件获取电流应力最优的移相角模型,结合虚拟电压补偿方案估算传输功率值以提高负载突变及输入电压扰动时的动态响应速度。该方法在保证电流应力优化的同时,能够实现快速的动态响应,并且参数易于调节,可移植性好。最后,搭建了一台小功率样机进行三种方案的对比实验,验证了该文控制方法的正确性及优越性。

关键词：双有源桥DC-DC变换器三重移相电流应力动态性能虚拟电压补偿

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实验中角色的分工扮演与轮换

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物理通报 2009年第11期30卷 45-47页

作者：施安帮石狮石光华侨联合中学

我国基础教育课程改革于1999年正式启动，在各实验区开展已经有了一段时间，各地在一定程度上有了突破性的进展．比如小组间的合作学习被经常应用人课堂，成为教师转变传统教学模式与学生改变原有学习方式的载体．然而许多实验学校的教... 详细信息

我国基础教育课程改革于1999年正式启动，在各实验区开展已经有了一段时间，各地在一定程度上有了突破性的进展．比如小组间的合作学习被经常应用人课堂，成为教师转变传统教学模式与学生改变原有学习方式的载体．然而许多实验学校的教师却只是一味的模仿这种形式，并没有更深层次地去思考如何让小组的合作更加有成效，让更多的学生得到全方位的发展．本文就如何更有效地开展学生小组合作探究提出了新的看法和实施的具体方案．

关键词：实验区分工合作学习传统教学模式课程改革基础教育学习方式突破性

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Adaptive Space Expansion for Fast Motion Planning

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IEEE/CAA Journal of Automatica Sinica 2024年第6期11卷 1499-1514页

作者： Shenglei shi Jiankui Chen State Key Laboratory of Digital Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The sampling process is very inefficient for sam-pling-based motion planning algorithms that excess random sam-ples are generated in the planning *** this paper,we pro-pose an adaptive space expansion(ASE)approach which belongs to the informed sampling category to improve the sampling effi-ciency for quickly finding a feasible *** ASE method enlarges the search space gradually and restrains the sampling process in a sequence of small hyper-ellipsoid ring subsets to avoid exploring the unnecessary ***,for a con-structed small hyper-ellipsoid ring subset,if the algorithm cannot find a feasible path in it,then the subset is ***,the ASE method successively does space exploring and space expan-sion until the final path has been ***,we present a particular construction method of the hyper-ellipsoid ring that uniform random samples can be directly generated in *** last,we present a feasible motion planner BiASE and an asymptoti-cally optimal motion planner BiASE*using the bidirectional exploring method and the ASE *** demon-strate that the computation speed is much faster than that of the state-of-the-art *** source codes are available at https://***/shshlei/ompl.

关键词： Adaptive space expansion(ASE) hyper-ellipsoid ring informed sampling motion planning.

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No Reference Image Sharpness Assessment Based on Global Color Difference Variation

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Chinese Journal of Electronics 2024年第1期33卷 293-302页

作者： Chenyang shi Yandan LIN School of Artificial Intelligence Anhui Polytechnic University School of Mechanical Engineering Anhui Polytechnic University Department of Light Sources and Illuminating Engineering Fudan University Academy for Engineering & Technology Fudan University

Image quality assessment(IQA) model is designed to measure the image quality in consistent with subjective ratings by computational models. In this research, a valid no reference IQA(NR-IQA) model for color image sharpness assessment is proposed based on local color difference map in a color space. In the proposed model, the absolute color difference variation and relative color difference variation are combined to evaluate sharpness in YIQ color space(a color coordinate system for the development of the United States color television system). The difference between sharpest and blurriest spot of an image is represented by the absolute color difference variation, and relative color difference variation expresses the variation in the image content. Extensive experiments are performed on five publicly available benchmark synthetic blur databases and two real blur databases, and the results prove that the proposed model work better than the other state-of-the-art and latest NR-IQA models for the prediction accuracy on blurry images. Besides, the model maintains the lowest computational complexity.

关键词： Image quality TV Image color analysis Databases Computational modeling Color Predictive models

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An uncertainty investigation for liner impedance eduction methods

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Chinese Journal of Aeronautics 2024年第3期37卷 49-59页

作者： Weihao shi Xiaodong JING School of Energy and Power Engineering Beihang UniversityBeijing 100191China

Impedance eduction methods have been developed for decades to meet the increasing need for high-quality impedance data in the design and optimization of acoustic *** this end,it is important to fully investigate the uncertainty problem,to which only limited attention has been devoted so *** paper considers the possibility of acoustically-induced structural vibration as a nonnegligible uncertainty or error source in impedance eduction *** the frequency moves away from the resonant frequency,with the increase in the value of cavity reactance,the acoustic particle velocity inside liner orifices possibly decreases to the extent comparable to the vibration velocity of liner facing ***,the acoustically-induced vibration,although generally being weak except at the inherent structural frequencies,may considerably affect the impedance eduction results near the anti-resonant frequency where the liner has poor *** demonstrate the effect of structural vibration,the vibration velocity of liner facing sheet is estimated from the experimentally educed admittance of the liner samples whose orifices are sealed with ***,a three-dimensional numerical model is set up,in which normal particle velocity is introduced over the solid portion of liner facing sheet to imitate structural vibration,rather than directly solving the acoustic-structural coupling *** shown by the results,the vibration of liner facing sheet,whose velocity is as small as estimated by the experiment,can result in anomalous deviation of the educed impedance from the impedance model near the anti-resonant *** trend that the anomalous deviation varies with frequency is numerically captured.

关键词： Impedance eduction Uncertainty analysis Acoustically-induced structural vibration Anti-resonant frequency Perforated liner

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Quantization and Event-Triggered Policy Design for Encrypted Networked Control

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 946-955页

作者： Yongxia shi Ehsan Nekouei the Department of Electrical Engineering City University of Hong KongHong KongChina

This paper proposes a novel event-driven encrypted control framework for linear networked control systems(NCSs),which relies on two modified uniform quantization policies,the Paillier cryptosystem,and an event-triggered *** to the fact that only integers can work in the Pailler cryptosystem,both the real-valued control gain and system state need to be first quantized before *** is dramatically different from the existing quantized control methods,where only the quantization of a single value,e.g.,the control input or the system state,is *** handle this issue,static and dynamic quantization policies are presented,which achieve the desired integer conversions and guarantee asymptotic convergence of the quantized system state to the ***,the quantized system state is encrypted and sent to the controller when the triggering condition,specified by a state-based event-triggered strategy,is *** doing so,not only the security and confidentiality of data transmitted over the communication network are protected,but also the ciphertext expansion phenomenon can be ***,by tactfully designing the quantization sensitivities and triggering error,the proposed event-driven encrypted control framework ensures the asymptotic stability of the overall closedloop ***,a simulation example of the secure motion control for an inverted pendulum cart system is presented to evaluate the effectiveness of the theoretical results.

关键词： Cyber-security encrypted control event-triggered control(ETC) networked control systems(NCSs) semi-homomorphic encryption

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Families of Schmidt-number witnesses for high dimensional quantum states

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Communications in Theoretical Physics 2024年第8期76卷 44-51页

作者： Xian shi College of Information Science and Technology Beijing University of Chemical TechnologyBeijing 100029China

Higher dimensional entangled states demonstrate significant advantages in quantum information processing tasks. The Schmidt number is a quantity of the entanglement dimension of a bipartite state. Here we build families of k-positive maps from the symmetric information complete positive operator-valued measurements and mutually unbiased bases, and we also present the Schmidt number witnesses, correspondingly. At last, based on the witnesses obtained from mutually unbiased bases, we show the distance between a bipartite state and the set of states with a Schmidt number less than k.

关键词： Schmidt number entanglement witness mutually unbiased bases

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Cloud-Edge Collaborative Federated GAN Based Data Processing for IoT-Empowered Multi-Flow Integrated Energy Aggregation Dispatch

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Computers, Materials & Continua 2024年第7期80卷 973-994页

作者： Zhan shi Electric Power Dispatching Control Center Guangdong Power Grid Co.Ltd.Guangzhou510030China

The convergence of Internet of Things(IoT),5G,and cloud collaboration offers tailored solutions to the rigorous demands of multi-flow integrated energy aggregation dispatch data *** generative adversarial networks(GANs)are instrumental in resource scheduling,their application in this domain is impeded by challenges such as convergence speed,inferior optimality searching capability,and the inability to learn from failed decision making ***,a cloud-edge collaborative federated GAN-based communication and computing resource scheduling algorithm with long-term constraint violation sensitiveness is proposed to address these *** proposed algorithm facilitates real-time,energy-efficient data processing by optimizing transmission power control,data migration,and computing resource *** employs federated learning for global parameter aggregation to enhance GAN parameter updating and dynamically adjusts GAN learning rates and global aggregation weights based on energy consumption constraint *** results indicate that the proposed algorithm effectively reduces data processing latency,energy consumption,and convergence time.

关键词： IoT federated learning generative adversarial network data processing multi-flowintegration energy aggregation dispatch

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