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Reduction Kinetics of Fe-based Oxygen Carriers Using Syngas in a Honeycomb Fixed-Bed Reactor for Chemical-Looping Combustion

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Journal of Thermal Science 2020年第1期29卷 13-24页

作者： liu xiangyu ZHANG Hao HONG Hui Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Chemical-looping combustion(CLC)is considered to be a vital method for utilizing hydrocarbon fuel with low carbon emissions.A honeycomb fixed-bed reactor is a new kind of reactor for ***,the further application of the reactor is limited by the inadequacy of the kinetic equations for *** this paper,the experimental studies on the kinetic of Fe-based oxygen carriers were carried out by the CLC experiments using syngas which was obtained from one typical type of coal gasification *** experimental results show that there were two individual stages for the kinetic characteristics during the fuel reaction ***,the CLC fuel reaction process could be described by a two-stage unreacted-core shrinking model and the reaction rate equations for each of the two phases were *** both stages,the dominant resistances were *** activation energy and the reaction order in both stages were calculated respectively as *** the experimental results of reaction rate with the calculated results of the obtained rate equations,it could be clearly seen that the reaction kinetics model was appropriate for the CLC in the honeycomb *** work is expected to provide a guideline for the future development and industrial design of the honeycomb CLC reactors from the perspective of kinetics.

关键词： chemical-looping combustion honeycomb reactor reaction kinetics

Exploring multiamplitude voltage modulation to improve spectrum efficiency in low-complexity visible-light communication

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Science China(Information Sciences) 2019年第8期62卷 56-74页

作者： xiangyu liu Xuetao WEI Lei GUO Yejun liu School of Computer Science and Engineering Northeastern University School of Information Technology University of Cincinnati School of Communication and Information Engineering Chongqing University of Posts and Telecommunications

Owing to the recent advancements in the Internet of Things(IoT), an increasing number of IoT devices have led to frequency crowding in wireless networks. The low-complexity visible light communication(VLC) system is a promising solution for indoor frequency-crowded wireless networks owing to the ubiquity of light-emitting diodes(LEDs) and readily deployable, low-cost modulation methods. However, due to the inherent limitations of LED materials and growth of data from IoT applications, low-complexity VLC systems can barely boost the data throughput without adding complex modulations and circuits. This study aims to design and implement a spectrum-efficient, low-complexity VLC system to improve data throughput with very little cost to support indoor IoT applications. This system uses multiamplitude voltage to transmit multiple bit streams simultaneously, making it a novel system. However, it is not trivial to achieve this goal as the varying voltage can cause the LEDs to flicker. Therefore, we further propose a voltage-to-current amplifier circuit, which effectively mitigates the effects of changes in the LED’s brightness upon human eyes. Finally, we evaluate the system under different speeds, distances, and angles. Extensive experiments demonstrate promising results from the viewpoint of spectrum efficiency, throughput, bit-error rate, and user perception.

关键词： visible light communication amplitude modulation spectral efficiency

MBB-IoT:Construction and Evaluation of IoT DDoS Traffic Dataset from a New Perspective

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Computers, Materials & Continua 2023年第8期76卷 2095-2119页

作者： Yi Qing xiangyu liu Yanhui Du Department of Artificial Intelligence People’s Public Security University of ChinaBeijing100038China Department of Cybersecurity People’s Public Security University of ChinaBeijing100038China

Distributed Denial of Service(DDoS)attacks have always been a major concern in the security *** the release of malware source codes such as BASHLITE and Mirai,Internet of Things(IoT)devices have become the new source of DDoS attacks against many Internet *** there are many datasets in the field of IoT intrusion detection,such as Bot-IoT,ConstrainedApplication Protocol–Denial of Service(CoAPDoS),and LATAM-DDoS-IoT(some of the names of DDoS datasets),which mainly focus on DDoS attacks,the datasets describing new IoT DDoS attack scenarios are extremely rare,and only N-BaIoT and IoT-23 datasets used IoT devices as DDoS attackers in the construction process,while they did not use Internet applications as victims *** supplement the description of the new trend of DDoS attacks in the dataset,we built an IoT environment with mainstream DDoS attack tools such as Mirai and BASHLITE being used to infect IoT devices and implement DDoS attacks against WEB ***,data aggregated into a dataset namedMBB-IoTwere captured atWEBservers and IoT *** the MBB-IoT dataset was split into a training set and a test set,it was applied to the training and testing of the Random Forests classification *** multi-class classification metrics were good and all above 90%.Secondly,in a cross-evaluation experiment based on Support Vector Machine(SVM),Light Gradient Boosting Machine(LightGBM),and Long Short Term Memory networks(LSTM)classification algorithms,the training set and test set were derived from different datasets(MBB-IoT or IoT-23),and the test performance is better when MBB-IoT is used as the training set.

关键词： Intrusion detection IoT malware botnet DDoS dataset

HY-PC:Enabling Consistent Positioning and Communication Using Visible Light

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China Communications 2023年第4期20卷 180-194页

作者： xiangyu liu Yaoheng Chen Lei Guo Song Song School of Information Science and Engineering Shenyang Ligong UniversityShenyang 110158China Department of Computer Science and Engineering Southern University of Science and TechnologyShenzhen 518055China School of Communication and Information Engineering Chongqing University of Posts and TelecommunicationsChongqing 400065China Hangzhou Institute of Advanced Technology Hangzhou 310056China Institute of Intelligent Communications and Network Security Chongqing University of Posts and TelecommunicationsChongqing 400065China

Visible light(VL)plays an important role in achieving high-precision positioning and low bit error radio(BER)data ***,most VL-based systems can not achieve positioning and communication,*** are two problems:1)the hybrid systems are difficult to extract distinguishable positioning beacon features without affecting communication performance,2)in the hybrid systems,the lost data bits in the inter-frame gap(IFG)are hard to recover,which affects positioning and communication ***,in this article,we propose a novel VL-based hybrid positioning and communication system,named HY-PC system,to solve the above ***,we propose the robust T-W mapping for recognizing specific Light Emitting Diodes(LEDs),which can provide stable LED recognition accuracy without adding extra beacon data and does not decrease the communication ***,we also propose the novel linear block coding and bit interleaving mechanism,which can recover the lost data bits in the IFG and improve data communication ***,we use commercial off-the-shelf devices to implement our HY-PC system,extensive experimental results show that our HY-PC system can achieve consistent high-precision positioning and low-BER data communication,simultaneously.

关键词： visible light positioning visible light communication T-W Mapping linear block coding bit interleaving

Dynamic Visible Light Positioning Based on Enhanced Visual Target Tracking

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China Communications 2023年第10期20卷 276-291页

作者： xiangyu liu Jingyu Hao Lei Guo Song Song School of Information Science and Engineering Shenyang Ligong UniversityShenyang 110158China Department of Computer Science and Engineering Southern University of Science and TechnologyShenzhen 518055China School of Computer Science and Engineering Northeastern UniversityShenyang 110819China School of Communication and Information Engineering Chongqing University of Posts and TelecommunicationsChongqing 400065China Hangzhou Institute of Advanced Technology Hangzhou 310056China Institute of Intelligent Communications and Network Security Chongqing University of Posts and TelecommunicationsChongqing 400065China

In visible light positioning systems,some scholars have proposed target tracking algorithms to balance the relationship among positioning accuracy,real-time performance,and ***,there are still two problems:(1)When the captured LED disappears and the uncertain LED reappears,existing tracking algorithms may recognize the landmark in error;(2)The receiver is not always able to achieve positioning under various moving *** this paper,we propose an enhanced visual target tracking algorithm to solve the above ***,we design the lightweight recognition/demodulation mechanism,which combines Kalman filtering with simple image preprocessing to quickly track and accurately demodulate the ***,we use the Gaussian mixture model and the LED color feature to enable the system to achieve positioning,when the receiver is under various moving *** results show that our system can achieve high-precision dynamic positioning and improve the system’s comprehensive performance.

关键词： visible light positioning visual target tracking gaussian mixture model kalman filtering system performance

Double-face intelligent hole position planning method for precision blasting in roadways using a computer-controlled drill jumbo

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International Journal of Minerals,Metallurgy and Materials 2023年第6期30卷 1025-1037页

作者： Haojun Wu Min Gong Renshu Yang Xiaodong Wu xiangyu liu School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China

To solve the uneven burden of same-type holes reducing the blasting efficiency due to the limitation of drilling equipment,we need a double-face program-controlled planning method for hole position parameters used on a computer-controlled drilling *** cross-section splits into even and uneven *** also considers the uneven burden at the hole’s entrance and *** the uneven area,various qualifying factors are made to optimize the hole spacing and maximize the burden uniformity,combined with the features of the area edges and gridbased segmentation *** hole position coordinates and angles in the even area are derived using recursion and iteration *** a case,this method presents all holes in a 4.8 m wide and 3.6 m high *** with the design produced by the drawing method,our planning in the uneven area improved the standard deviation of the hole burden by 40%.The improved hole layout facilitates the evolution of precise,efficient,and intelligent blasting in underground mines.

关键词： drill and blast method green mine blast design drilling jumbo burden

Electrodeposition of aluminum on aluminum surface from molten salt

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Acta Metallurgica Sinica(English Letters) 2011年第6期24卷 443-448页

作者： Wenmao HUANG xiangyu XIA Bin liu Yu liu Haowei WANG Naiheng MA State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200240 China Manuscript received 7 March 2011 in revised form 29 June 2011

The surface morphology, microstructure and composition of the aluminum coating of the electrodeposition plates in AlCl3-NaCl-KCl molten salt with a mass ratio of 8：1：1 were investigated by SEM and EDS. The binding force was measured by splat-cooling method and bending method. The results indicate that the coatings with average thicknesses of 12 and 9 μm for both plates treated by simple grinding and phosphating are compacted, continuous and well adhered respectively. Tetramethylammonium chloride （TMAC） can effectively prevent the growth of dendritic crystal, and the anode activation may improve the adhesion of the coating. Binding force analysis shows that both aluminum coatings are strongly adhered to the substrates.

关键词： Aluminum Electrodeposition Surface morphology Molten salt

Comment on:“Stereotactic body radiation therapy versus radiofrequency ablation in patients with small hepatocellular carcinoma:a systematic review and meta-analysis”

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Hepatobiliary Surgery and Nutrition 2022年第4期11卷 647-648页

作者： xiangyu liu Meilin Zhu Department of Gastroenterology Jining First People’s HospitalJiningChina Department of Geriatrics Jining First People’s HospitalJiningChina

We are grateful to Hepatobiliary Surg Nutr for publishing the study entitled“Stereotactic body radiation therapy versus radiofrequency ablation in patients with small hepatocellular carcinoma:a systematic review and meta-analysis”.In this well-designed study,the authors concluded that in patients with small hepatocellular carcinoma,stereotactic body radiation therapy has a higher local control rate but poorer prognosis than radiofrequency ablation;in addition,the local toxicity of the two treatments was comparable(1).While we read the article with pleasure,it must be noted that this study raises some thought-provoking issues.

关键词： patients Stereo analysis

Particle detector readout integrated circuit of 0.18μm technology with 164 e equivalent noise charge

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Nuclear Science and Techniques 2011年第6期22卷 358-365页

作者： LI xiangyu liu Haifeng ZHANG Qi SUNYihe Tsinghua National Laboratory for Information Science and Technology Institute of Mieroelectronics Tsinghua University Beijing 100084 China

Integrated circuits of deep submicron(DSM) CMOS technology are advantageous in volume density, power consumption and thermal noise for multichannel particle detection systems,but there are challenges in the front-end circuit *** this paper,we present a 0.18μm CMOS front-end readout circuit for low noise CdZnTe detectors in tens of pF *** to the noise and gate leak problems in DSM technologies are discussed in detail.A prototype chip was designed,with a charge sensitive preamplifier,a 4th order semi-Gaussian shaper and several output *** results show that the chip has an equivalent noise charge of 164 e,without connecting it to a detector,with an integral nonlinearity of<0.21%and differential nonlinearity of<3.75%.

关键词：电荷灵敏前置放大器 CMOS技术粒子探测器集成电路热噪声前端电路设计 DSM技术读数