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Influence of Prior Austenite Deformation and Non-Metallic Inclusions on Ferrite Formation in Low-Carbon Steels

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Journal of Iron and Steel Research International 2010年第6期17卷 36-42页

作者： ZHANG Chi XIA zhi-xin YANG zhi-gang liu zhi-hao Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

Effects of prior austenite deformation and non-metallic inclusions on the ferrite nucleation and grain refine- ment of two kinds of low-carbon steels have been studied. The ferrite nucleation on MnS and V（C, N） is observed. The combination of thermomeehanical processes with adequate amounts of non-metallic inclusions formed in low-car- bon steels could effectively refine the grain size and the microstructure. Ferrite nucleated on the single MnS or V（C, N） inclusions and complex MnS＋V（C,N） inclusion. The proper addition of elements S and V could effectively promote the formation of ferrite and further refinement of ferrite grains.

关键词： austenite deformation non-metallic inclusion ferrite nucleation low-carbon steel

Bandwidth Allocation with Minimum Rate Constraints in Cluster-based Femtocell Networks

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International Journal of Automation and computing 2015年第1期12卷 77-82页

作者： Kai Ma Liang Li Jie Yang zhi-xin liu xin-Bin Li xin-Ping Guan School of Electrical Engineering Key Laboratory of Industrial Computer Control Engineering of Hebei Province Yanshan University Department of Automation Shanghai Jiao Tong University Key Laboratory of System Control and Information ProcessingMinistry of Education

Inter-femtocell interference becomes serious when femtocells are densely deployed. To mitigate the inter-femtocell interference, this paper proposes a cluster-based bandwidth allocation algorithm. We create femtocell clusters by constructing a weighted interference graph and allocate bandwidth to each cluster based on a Nash bargaining solution(NBS). Simulation results show that the cluster-based bandwidth allocation algorithm can reduce the inter-femtocell interference and meet the minimum rate constraint of each cluster.

关键词： Femtocell cluster inter-femtocell interference bandwidth allocation Nash bargaining solution(NBS)

A Power- and Coverage-aware Clustering Scheme for Wireless Sensor Networks

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International Journal of Automation and computing 2010年第4期7卷 500-508页

作者： Liang Xue xin-Ping Guan zhi-xin liu Qing-Chao Zheng Research Office of Networking Control Institute of Electrical Engineering Yanshan University Qinhuangdao 066004 PRC School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University Shanghai 200240 PRC

A common and critical operation for wireless sensor networks is data gathering. The efficient clustering of a sensor network that can save energy and improve coverage efficiency is an important requirement for many upper layer network functions. This study concentrates on how to form clusters with high uniformity while prolonging the network lifetime. A novel clustering scheme named power- and coverage- aware clustering （PCC） is proposed, which can adaptively select cluster heads according to a hybrid of the nodesI residual energy and loyalty degree. Additionally, the PCC scheme is independent of node distribution or density, and it is free of node hardware limitations, such as self-locating capability and time synchronization. Experiment results show that the scheme performs well in terms of cluster size （and its standard deviation）, number of nodes alive over time, total energy consumption, etc.

关键词： Wireless sensor networks clustering high-uniformity energy and coverage efficiency network lifetime

A Stackelberg Game for Spectrum Leasing in Cooperative Cognitive Radio Networks

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International Journal of Automation and computing 2013年第2期10卷 125-133页

作者： Xiao-Cheng Wang xin-Ping Guan Qiao-Ni Han zhi-xin liu Kai Ma Institute of Electrical Engineering Key Laboratory of Industrial Computer Control Engineering of Hebei Province Yanshan University School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University

According to the property-rights model of cognitive radio, primary users （PUs） who own the spectrum resource have the right to lease part of spectrum to secondary users （SUs） in exchange for appropriate profit. In this paper, we propose a pricing-based spectrum leasing framework between one PU and multiple SUs. In this scenario, the PU attempts to maximize its utility by setting the price of spectrum. Then, the selected SUs have the right to decide their power levels to help PU s transmission, aiming to obtain corresponding access time. The spectrum leasing problem can be cast into a stackelberg game, where the PU plays the seller-level game and the selected SUs play the buyer-level game. Through analysis based on the backward induction, we prove that there exists a unique equilibrium in the stackelberg game with certain constraints. Numerical results show that the proposed pricing-based spectrum leasing framework is effective, and the performance of both PU and SUs is improved, compared to the traditional mechanism without cooperation.

关键词： Cognitive radio spectrum leasing power control cooperative transmission pricing stackelberg game

Microphase Separation of Semiflexible Ring Diblock Copolymers

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Chinese Journal of Polymer Science 2024年第2期42卷 267-276,I0011页

作者： Dan-Yan Qin Sheng-Da Zhao zhi-xin liu Jing Zhang xing-Hua Zhang School of Physical Science and Engineering Beijing Jiaotong UniversityBeijing100044China

Aiming at the difficult problem of solving the conformation statistics of complex polymers, this study presents a novel and concise conformation statistics theoretical approach based on Monte Carlo and Neural Network method. This method offers a new research idea for investigating the conformation statistics of complex polymers, characterized by its simplicity and practicality. It can be applied to more complex topological structure, more higher degree of freedom polymer systems with higher dimensions, theory research on dynamic self-consistent field theory and polymer field theory, as well as the analysis of scattering experimental data. The conformation statistics of complex polymers determine the structure and response properties of the system. Using the new method proposed in this study, taking the semiflexible ring diblock copolymer as an example, Monte Carlo simulation is used to sample this ring conformation to construct the dataset of polymer. The structure factor describing conformation statistics are expressed as continuous functions of structure parameters by neural network supervised learning. This is the innovation of this work. As an application, the structure factors represented by neural networks were introduced into the random phase approximation theory to study the microphase separation of semiflexible ring diblock copolymers. The influence of the ring's topological properties on the phase transition behavior was pointed out.

关键词： Ring copolymer Diblock copolymers Semiflexible The order-disorder transition

Joint Slot Scheduling and Power Allocation in Clustered Underwater Acoustic Sensor Networks

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IEEE/CAA Journal of Automatica Sinica 2023年第6期10卷 1501-1503页

作者： zhi-xin liu Xiao-Cao Jin Yuan-Ai Xie Yi Yang School of Electrical Engineering Yanshan UniversityQinhuangdao 066004China

Dear Editor, This letter deals with the joint slot scheduling and power allocation in clustered underwater acoustic sensor networks(UASNs),based on the known clustering and routing information, to maximize the network's energy efficiency(EE). Based on the block coordinated decent(BCD) method, the formulated mixed-integer non-convex problem is alternatively optimized by leveraging the KuhnMunkres algorithm.

关键词： network Slot Acoustic

Molecular Characterization of Banana streak virus Isolate from Musa Acuminata in China

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Virologica Sinica 2011年第6期26卷 393-402页

作者： Jun Zhuang Jian-hua Wang xin Zhang zhi-xin liu Agricultural Ministry Key Laboratory of Tropical Crop Biotechnology Institute of Tropical Bioscience and Biotechnology Chinese Academy of Tropical Agricultural Sciences Haikou 571101 China Institute of Plant Virology Fujian Agriculture and Forestry University Fuzhou 350002 China Environment and plant protection institute Chinese Academy of Tropical Agricultural Sciences Danzhou 571734 China

Banana streak virus （BSV）, a member of genus Badnavirus, is a causal agent of banana streak disease throughout the world. The genetic diversity of BSVs from different regions of banana plantations has previously been investigated, but there are relatively few reports of the genetic characteristic of episomal （non-integrated） BSV genomes isolated from China. Here, the complete genome, a total of 7722bp （GenBank accession number DQ092436）, of an isolate of Banana streak virus （BSV） on cultivar Cavendish （BSAcYNV） in Yunnan, China was determined. The genome organises in the typical manner of badnaviruses. The intergenic region of genomic DNA contains a large stem-loop, which may contribute to the ribosome shift into the following open reading frames （ORFs）. The coding region of BSAcYNV consists of three overlapping ORFs, ORF 1 with a non-AUG start codon and ORF2 encoding two small proteins are individually involved in viral movement and ORF3 encodes a polyprotein. Besides the complete genome, a defective genome lacking the whole RNA leader region and a majority of ORF1 and which encompasses 6525bp was also isolated and sequenced from this BSV DNA reservoir in infected banana plants. Sequence analyses showed that BSAcYNV has closest similarity in terms of genome organization and the coding assignments with an BSV isolate from Vietnam （BSAcVNV）. The corresponding coding regions shared identities of 88% and -95% at nucleotide and amino acid levels, respectively. Phylogenetic analysis also indicated BSAcYNV shared the closest geographical evolutionary relationship to BSAcVNV among sequenced banana streak badnaviruses.

关键词： BSAcYNV Complete genome Defective genome Identity Phylogenetic analysis

Hunting problems of multi-quadrotor systems via bearing-based hybrid protocols with hierarchical network

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Chinese Physics B 2020年第5期29卷 194-202页

作者： Zhen Xu xin-zhi liu Qing-Wei Chen Zi-xing Wu School of Automation Nanjing University of Science and TechnologyNanjing 210094China Department of Applied Mathematics University of WaterlooWaterloo N2L 3G1Canada

Bearing-based hunting protocols commonly adopt a leaderless consensus method,which requests an entire state of the target for each agent and ignores the necessity of collision *** investigate a hunting problem of multi-quadrotor systems with hybrid bearing protocols,where the quadrotor systems are divided into master and slave groups for reducing the onboard loads and collision *** masters obtain the entire state of the target,whose hybrid protocols are based on the displacement and bearing constraints to maintain formation and to avoid the collision in the hunting ***,the slaves’protocols merely depend on the part state of the masters to reduce loads of data *** also investigate the feasibility of receiving the bearing state from machine *** simulation results are given to illustrate the effectiveness of the proposed hybrid bearing protocols.

关键词： hunting problem multi-quadrotor system bearing constraint hierarchical network

Crystal structure and negative thermal expansion of solid solution Lu_2W_(3-x)Mo_xO_(12)

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International Journal of Minerals,Metallurgy and Materials 2010年第6期17卷 786-790页

作者： Jie Peng xin-zhi liu Fu-li Guo Song-bai Han Yun-tao liu Dong-feng Chen Zhong-bo Hu Experimental Physics Center Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China College of Chemistry and Chemical Engineering Graduate University of Chinese Academy of Sciences Beijing 100049 China China Institute of Atomic Energy Beijing 102413 China College of Chemistry Beijing Normal University Beijing 100875 China

A new series of solid solutions Lu2W3-xMoxO12 （0.5≤r≤2.5） were successfully synthesized by the solid-state method. Their crystal structure and negative thermal expansion properties were studied using high-temperature X-ray powder diffraction and the Rietveld method. All samples of rare-earth ttmgstates and molybdates are found to crystallize in the same orthorhombic structure with space group Pnca and show the negative thermal expansion phenomena related to transverse vibration of bridging oxygen atoms in the structure. Thermal expansion coefficients （TEC） of Lu2W3_xMoxO12 are determined as -20.0× 10^-6 K^-1 for x=0.5 and -16.1×10^-6 K^-1 for x=2.5 but -18.6× 10^-6 and -16.9× 10^-6K^-1 for unsubstituted Lu2W3012 and Lu2M03012 in the identical temperature range of 200 to 800℃. High-temperature X-ray diffraction （XRD） data and bond length analysis suggest that the difference between W-O and Mo-O bond is responsible for the change of TECs after the element substitution in this series of solid solutions.

关键词： rare earth compounds molybdates rare-earth tungstates negative thermal expansion X-ray diffraction