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The Journal of China Universities of Posts and Telecommunications 2011年第3期18卷 8-15页

作者： LI Hong-jia HU Dan XU Xiao-dong TAO Xiao-feng ZHANG Ping Wireless Technology Innovation Institute Key Laboratory of Universal Wireless Communication Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

In the two-tier femtocell network, a central macroceU is underlaid with a large number of shorter range femtocell hotspots, which is preferably in the universal frequency reuse mode. This kind of new network architecture brings about urgent challenges to the schemes of interference management and the radio resource allocation. Motivated by these challenges, three contributions are made in this paper： 1） A novel joint subchannel and power allocation problem for orthogonal frequency division multiple access （OFDMA） downlink based femtocells is formulated on the premise of minimizing radiated interference of every Femto base station. 2） The pseudo-handover based scheduling information exchange method is proposed to exchange the co-tier and cross-tier information, and thus avoid the collision interference. 3） An iterative scheme of power control and subchannel is proposed to solve the formulated problem in contribution 1）, which is an NP-complete problem. Through simulations and comparisons with four other schemes, better performance in reducing interference and improving the spectrum efficiency is achieved by the proposed scheme.

关键词： femtocell OFDMA interference mitigation resource management power control

Annealing behavior of rolled AZ31 alloy sheet

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中国有色金属学会会刊：英文版 2006年第A03期16卷 1716-1720页

作者：彭伟平李培杰曾攀 Key Laboratory for Advanced Manufacturing by Materials Processing Technology Tsinghua UniversityBeijing 100084China

The annealed microstructures of the rolled AZ31 alloy sheets were examined by using light optical microscopy. The mechanical properties were measured by tensile testing, with their crystal orientations analyzed by X-ray diffraction (XRD). After the annealing treatment, the elongated grains were transformed to equiaxed grains with uniform and homogeneous structures. The changes of microstructure decreased the yield strength and enhanced the elongation. The analysis of XRD shows that the AZ31 alloy sheet possesses intense basal-texture, which is weakened during the recrystallization while reinforced during the grain growth. The intense basal-texture induces low ductility, which hence makes the further rolling more difficult. The results indicate that the optimum annealing treatment during AZ31 alloys sheet rolling is at about 300℃for 60-120 min.

关键词：热处理工艺合金退火工艺微观结构

Intensity measures for seismic liquefaction hazard evaluation of sloping site

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Journal of Central South University 2015年第10期22卷 3999-4018页

作者：陈志雄程印肖杨卢谅阳洋 Key Laboratory of New Technology for Construction of Cities in Mountain Area of Ministry of Education(Chongqing University) School of Civil Engineering Chongqing University Kandilli Observatory and Earthquake Research Institute Bogazici University

This work investigates the correlation between a large number of widely used ground motion intensity measures(IMs) and the corresponding liquefaction potential of a soil deposit during earthquake loading. In order to accomplish this purpose the seismic responses of 32 sloping liquefiable site models consisting of layered cohesionless soil were subjected to 139 earthquake ground motions. Two sets of ground motions, consisting of 80 ordinary records and 59 pulse-like near-fault records are used in the dynamic analyses. The liquefaction potential of the site is expressed in terms of the the mean pore pressure ratio, the maximum ground settlement, the maximum ground horizontal displacement and the maximum ground horizontal acceleration. For each individual accelerogram, the values of the aforementioned liquefaction potential measures are determined. Then, the correlation between the liquefaction potential measures and the IMs is evaluated. The results reveal that the velocity spectrum intensity(VSI) shows the strongest correlation with the liquefaction potential of sloping site. VSI is also proven to be a sufficient intensity measure with respect to earthquake magnitude and source-to-site distance, and has a good predictability, thus making it a prime candidate for the seismic liquefaction hazard evaluation.

关键词： soil liquefaction liquefaction potential index intensity measure(IM) pore pressure generation seismic response prediction

Optimal Noise Suppression of Phase Damping Quantum Systems via Weak Measurement

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Journal of Systems Science & Complexity 2019年第5期32卷 1264-1279页

作者： HARRAZ Sajede CONG Shuang KUANG Sen Department of Automation University of Science and Technology of China

One qubit subjected to the effect of phase damping in a two-level quantum system with arbitrary pure initial state is studied in this paper. The aim of this paper is to find the optimal control scheme to correct the qubit back as close as possible to its initial state. The strength-dependent measurements and control correction rotation in different bases are designed to protect the arbitrary pure state of qubit. The authors design the optimal weak measurement strength to achieve the best trade-off between gaining the information of the system and the disturbance through *** authors study the suppression of phase damping in two cases: There is and isn’t the y component in initial state. The authors deduce the optimal parameters and performances of the control schemes for the various initial state situations. Simulation results demonstrate the effectiveness of the proposed control schemes.

关键词： Open quantum system optimal noise suppression phase damping quantum system control weak measurement

Information Freshness-Oriented Trajectory Planning and Resource Allocation for UAV-Assisted Vehicular Networks

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China Communications 2023年第5期20卷 244-262页

作者： Hao Gai Haixia Zhang Shuaishuai Guo Dongfeng Yuan School of Control Science and Engineering Shandong UniversityJinan 250061China Shandong Key Laboratory of Wireless Communication Technologies Shandong UniversityJinan 250061China China Academy of Information and Communication Technology(CAICT) Beijing 100191China

In this paper,multi-UAV trajectory planning and resource allocation are jointly investigated to improve the information freshness for vehicular networks,where the vehicles collect time-critical traffic information by on-board sensors and upload to the UAVs through their allocated spectrum *** adopt the expected sum age of information(ESAoI)to measure the network-wide information *** is jointly affected by both the UAVs trajectory and the resource allocation,which are coupled with each other and make the analysis of ESAoI *** tackle this challenge,we introduce a joint trajectory planning and resource allocation procedure,where the UAVs firstly fly to their destinations and then hover to allocate resource blocks(RBs)during a *** on this procedure,we formulate a trajectory planning and resource allocation problem for ESAoI *** solve the mixed integer nonlinear programming(MINLP)problem with hybrid decision variables,we propose a TD3 trajectory planning and Round-robin resource allocation(TTPRRA).Specifically,we exploit the exploration and learning ability of the twin delayed deep deterministic policy gradient algorithm(TD3)for UAVs trajectory planning,and utilize Round Robin rule for the optimal resource *** TTP-RRA,the UAVs obtain their flight velocities by sensing the locations and the age of information(AoI)of the vehicles,then allocate the RBs to the vehicles in a descending order of AoI until the remaining RBs are not sufficient to support another successful *** results demonstrate that TTP-RRA outperforms the baseline approaches in terms of ESAoI and average AoI(AAoI).

关键词： information freshness for vehicular networks multi-UAV trajectory planning resource allocation deep reinforcement learning

Potential dissemination mechanism of the tetC gene in Aeromonas media from the aerobic biofilm reactor under oxytetracycline stresses

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Journal of Environmental Sciences 2021年第7期33卷 90-99页

作者： Yanhong Shi Yu Zhang Xiangyang Wu Hong Zhang Min Yang Zhe Tian School of the Environment and Safety Engineering Jiangsu UniversityZhenjiang 212013China State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China

The tet C gene has been found to be one of the most widely distributed tetracycline resistance( tet) genes in various environmental niches, but the detailed dissemination mechanisms are still largely unknown. In the present study, 11 tet C-containing Aeromonas media strains were isolated from an aerobic biofilm reactor under oxytetracycline stresses, and the genome of one strain was sequenced using the Pac Bio RSII sequencing approach to reveal the genetic environment of tet C. The tet C gene was carried by an IS 26 composite transposon, named Tn 6434. The tet C-carrying Tn 6434 structure was detected in all of the A. media strains either in a novel plasmid p Aeme2( n = 9) or other DNA molecules( n = 2) by PCR screening. The NCBI database searching result shows that this structure was also present in the plasmids or chromosomes of other 13 genera, indicating the transferability of Tn 6434. Inverse PCR and sequencing confirmed that Tn 6434 can form a circular intermediate and is able to incorporate into a preexisting IS 26 element, suggesting that Tn 6434 might be responsible for the dissemination of tet C between different DNA molecules. This study will be helpful in uncovering the spread mechanism of tet genes in water environments.

关键词： Aeromonas media tetC IS 26 Circular intermediate Inverse PCR

Balmer H_α,H_β and H_γ Spectral Lines Intensities in High-Power RF Hydrogen Plasmas

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Plasma Science and Technology 2014年第3期16卷 219-222页

作者：王松柏雷光玖刘东平杨思泽 College of Physics and Information Engineering Fuzhou University School of Physics and Mechanical&Electrical Engineering Xiamen University Southwestern Institute of Physics

Hα（Balmer-alpha）, Hβ （Balmer-beta） and Hγ （Balmer-gamma） spectral line inten- sities in atomic hydrogen plasma are investigated by using a high-power RF source. The intensities of the Hα, Hβ and Hγ spectral lines are detected by increasing the input power （0-6 kW） of ICPs （inductively coupled plasmas）. With the increase of net input power, the intensity of Hα im- proves rapidly （0-2 kW）, and then reaches its dynamic equilibrium; the intensities of Hβ can be divided into three processes： obvious increase （0-2 kW）, rapid increase （2-4 kW）, almost constant （4-6 kW）; while the intensities of Hγ increase very slowly. The energy levels of the excited hydro- gen atoms and the splitting energy levels produced by an obvious Stark effect play an important role in the results.

关键词： Keywords: high-power RF (radio frequency) source ICPs (inductively coupled plasmas),Hα Hβ and Hγ spectral lines intensity Boltzmann distribution law Stark effect transitionprobability

A REVIEW ON ARTERY WALL SEGMENTATION TECHNIQUES AND INTIMA-MEDIA THICKNESS MEASUREMENT FOR CAROTID ULTRASOUND IMAGES

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Journal of Innovative Optical Health Sciences 2012年第1期5卷 75-84页

作者： XIN YANG WANJI HE KAITONG LI JIAOYING JIN XUMING ZHANG MING YUCHI MINGYUE DING State Key Laboratory for Multi-Spectral Information Processing Technologies Institute for Pattern Recognition and Artificial Intelligence(IPRAI)Huazhong University of Science and Technology Wuhan 430074HubeiChina Image Processing and Intelligence Control Key Laboratory of Education Ministry of China School of Life Science and Technology Huazhong University of Science and Technology Wuhan 430074HubeiChina

Stroke and heart attack,which could be led by a kind of cerebrovascular and cardiovascular disease named as atherosclerosis,would seriously cause human morbidity and *** is important for the early stage diagnosis and monitoring medical intervention of the *** stenosis is a classical atherosclerotic lesion with vessel wall narrowing down and accumulating plaques *** carotid artery of intima-media thickness(IMT)is a key indicator to the *** the development of computer assisted diagnosis technology,the imaging techniques,segmentation algorithms,measurement methods,and evaluation tools have made considerable *** imaging,being real-time,economic,reliable,and safe,now seems to become a standard in vascular assessment methodology especially for the measurement of *** review firstly attempts to discuss the clinical relevance of measurements in clinical practice at first,and then followed by the challenges that one has to face when approaching the segmentation of ultrasound ***,the commonly used methods for the IMT segmentation and measurement are ***,discussion and evaluation of different segmentation techniques are *** overview of summary and future perspectives is given finally.

关键词： Ultrasound(US)images carotid artery intima-media thickness(IMT) atherosclerosis image segmentation computer assisted diagnosis(CAD)

Processing parameter optimization of fiber laser beam welding using an ensemble of metamodels and MOABC

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Frontiers of Mechanical Engineering 2022年第4期17卷 243-259页

作者： Jianzhao WU Chaoyong ZHANG Kunlei LIAN Jiahao SUN Shuaikun ZHANG State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China Department of Mechanical Engineering National University of SingaporeSingapore 117575Singapore Walmart Global Technology Walmart Inc.BentonvilleAR 72712USA

In fiber laser beam welding(LBW),the selection of optimal processing parameters is challenging and plays a key role in improving the bead geometry and welding *** study proposes a multi-objective optimization framework by combining an ensemble of metamodels(EMs)with the multi-objective artificial bee colony algorithm(MOABC)to identify the optimal welding *** inverse proportional weighting method that considers the leave-one-out prediction error is presented to construct EM,which incorporates the competitive strengths of three *** constructs the correlation between processing parameters(laser power,welding speed,and distance defocus)and bead geometries(bead width,depth of penetration,neck width,and neck depth)with average errors of 10.95%,7.04%,7.63%,and 8.62%,*** the basis of EM,MOABC is employed to approximate the Pareto front,and verification experiments show that the relative errors are less than 14.67%.Furthermore,the main effect and the interaction effect of processing parameters on bead geometries are *** demonstrate that the proposed EM-MOABC is effective in guiding actual fiber LBW applications.

关键词： laser beam welding parameter optimization metamodel multi-objective

Microstructure and magnetocaloric properties of partially crystallized Gd_(60)Co_(30)Fe_(10)amorphous alloy prepared by different solidification cooling rates

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Rare Metals 2022年第1期41卷 246-253页

作者： Hui-Yan Zhang Zi-Yang Zhang Ya-Fang Xu Ai-Lin Xia Wei-Huo Li Fa-Chao Wang Shuang-Shuang Chen Gerard Sisó Key Laboratory of Green Fabrication and Surface Technology of Advanced Metal Materials(Anhui University of Technology) Ministry of Education School of Materials Science and Engineering Anhui University of Technology Departament d’Enginyeria Electro`nica-Escola d’Enginyeria Universitat Autònoma de Barcelona

The Gd_(60)Co_(30)Fe_(10)alloy ribbons with different solidification cooling rates were prepared by modifying the melt-spinning speed of 6.0,12.5,25.0 and 50.0 m·s^(-1)·With cooling rate decreasing,the(Fe,Co)5 Gd and hcp-Gd nanocrystalline was in situ precipitated among the amorphous matrix,which resulted in the composition change of the amorphous *** of the only slight amount of crystalline phase in Gd_(60)Co_(30)Fe_(10)alloys,the magnetic and magnetocaloric properties mainly depend on the amorphous phase,and all the magnetic entropy change versus temperature(|Δ|SMI-T)curves are table-like,indicating the suitability for Ericsson *** magnetic transition temperature of the Gd_(60)Co_(30)Fe_(10)alloy at a melt-spinning speed of 6.0 m·s^(-1) shifted obviously to the lower value with the applied magnetic fields *** peak value of magnetic entropy change(|ΔSMpk|)is 2.19 J·kg^(-1)·K^(-1)at217 K under the magnetic field change of 0-2 T,and the table-like region is 200-230 *** was proved that the moderate reduction of the cooling rate will not deteriorate the magnetocaloric performance of the Gd_(60)Co_(30)Fe_(10)ribbons seriously.

关键词： Magnetic refrigeration Amorphous-nanocrystalline composite In situ precipitation Magnetocaloric effect