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Channel Estimation for Reconfigurable Intelligent Surface Aided Multiuser Millimeter-Wave/THz Systems

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China Communications 2024年第3期21卷 91-103页

作者： Chu Hongyun pan Xue Li Baijiang School of Communications and Information Engineering Xi’an University of Posts and TelecommunicationsXi’an 710121China

It is assumed that reconfigurable intelligent surface(RIS)is a key technology to enable the potential of mmWave *** passivity of the RIS makes channel estimation difficult because the channel can only be measured at the transceiver and not at the *** this paper,we propose a novel separate channel estimator via exploiting the cascaded sparsity in the continuously valued angular domain of the cascaded channel for the RIS-enabled millimeter-wave/Tera-Hz systems,i.e.,the two-stage estimation method where the cascaded channel is separated into the base station(BS)-RIS and the RIS-user(UE)***,we first reveal the cascaded sparsity,i.e.,the sparsity exists in the hybrid angular domains of BS-RIS and the RIS-UEs separated channels,to construct the specific sparsity structure for RIS enabled multi-user ***,we formulate the channel estimation problem using atomic norm minimization(ANM)to enhance the proposed sparsity structure in the continuous angular domains,where a low-complexity channel estimator via Alternating Direction Method of Multipliers(ADMM)is *** findings demonstrate that the proposed channel estimator outperforms the current state-of-the-arts in terms of performance.

关键词： atomic norm minimization cascaded channel estimation convex optimization mmWave/THz reconfigurable intelligent surface(RIS) sparsity

造缝产烃还是改质造烃?——论含油气源岩层系的储集层属性和烃源岩属性

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地质学报 2022年第1期96卷 183-194页

作者：杨智邹才能吴松涛潘松圻李嘉蕊蒋文琦王小妮中国石油勘探开发研究院北京100083

源岩层系油气已成为世界油气工业体系中举足轻重的重点领域,未来发展潜力很大。本文通过深入解读含油气源岩层系的地质形成条件,发现储集层属性和烃源岩属性在根本上决定了源岩层系油气成功开发的技术路径。储集层属性是指储集层储存和... 详细信息

源岩层系油气已成为世界油气工业体系中举足轻重的重点领域,未来发展潜力很大。本文通过深入解读含油气源岩层系的地质形成条件,发现储集层属性和烃源岩属性在根本上决定了源岩层系油气成功开发的技术路径。储集层属性是指储集层储存和渗滤油气的物理性质及其相互关系,地史时期微—纳米级孔-喉-缝系统充注和聚集了大面积连续型油气资源,人工压裂形成缝网系统突破了致密储层的连通属性短板,成功开发了规模油气资源,突破流动属性短板可能是另一个发展方向。烃源岩属性是指烃源岩滞留、转化和排出油气的物理化学性质及其相互关系,包括已转化的滞留油气和未转化的残留有机质,滞留及潜在烃类资源规模巨大,地下人工加热等方式理论上可突破烃源岩的有机质数量和成熟度属性短板,可能是实现成功开发的有效路径。储集层属性和烃源岩属性是实现源岩层系油气规模发展的内在潜质基础,公共属性参数是外部环境基础。造缝产烃还是改质造烃?前提是准确研判优选何种内在属性参数,基础是系统整合优化所有外在属性参数,推动实现源岩层系油气商业化可持续发展,未来中低熟富有机质页岩及油页岩、中高熟富气态烃页岩层系、低变质程度富油煤岩、深层可气化煤炭等是值得期待的战略发展领域。

关键词：源岩层系油气储集层属性烃源岩属性微纳米孔喉系统煤岩油页岩油页岩气

A Generalized MSST Algorithm for Counting Points of Elliptic Curves over F_(p)^(n)

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Journal of Systems Science & Complexity 2024年第4期37卷 1738-1754页

作者： LI Xiao LV Chang pan Zhizhong Key Laboratory of Cyberspace Security Defense Institute of Information EngineeringChinese Academy of SciencesBeijing 100085China School of Cyber Security University of Chinese Academy of SciencesBeijing 100085China Huawei Technologies Co. Ltd.Shenzhen 518129China

Elliptic curve cryptography is an important part of nowaday's public key *** points of elliptic curves over finite fields is of great significance to the selection of safety *** present,there are many p-adic algorithms,such as SST algorithm,generalized AGM algorithm,Kedlaya algorithm,etc.,which can deal with the situation of finite fields of small *** this paper,the authors generalize the MSST algorithm of characteristic 2 to general fields of odd characteristic,and propose the generalized MSST *** generalized MSST algorithm is achieved by combining the advantages of the SST algorithm and the generalized AGM *** the time complexity of the multiplication of two n-bit numbers is denoted as O((n)^(μ)),then the time complexity of the generalized MSST algorithm is O(n^(2μ+1/1+μ)),which is the same as the improved SST *** practical experiments,the running time of the generalized MSST algorithm is less than that of the improved SST algorithm.

关键词： Elliptic curve generalized AGM algorithm generalized MSST algorithm SST algorithm

Experimental Investigation of the Operating Characteristics of a Pulsating Heat Pipe with Ultra-Pure Water and Micro Encapsulated Phase Change Material Suspension

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Journal of Thermal Science 2024年第2期33卷 457-468页

作者： SHI Weixiu SU Xiaoyang CHEN Hongdi pan Lisheng Beijing Engineering Research Center of Sustainable Energy and Buildings Beijing University of Civil Engineering and ArchitectureBeijing100044China School of Environment and Energy Engineering Beijing University of Civil Engineering and ArchitectureBeijing100044China State Key Laboratory of High Temperature Gas Dynamics Institute of MechanicsChinese Academy of SciencesBeijing100190China

The specific heat capacity of working fluid is an important influence factor on heat transfer characteristic of the pulsating heat pipe(PHP).Due to the relatively large specific heat capacity of micro encapsulated phase change material(MEPCM) suspension,a heat transfer performance experimental facility of the PHP was *** heat transfer characteristic with MEPCM suspension of different mass concentrations(0.5% and 1.0%) and ultra-pure water were compared *** was found that when the PHP uses MEPCM suspension as its working fluid,operating stability is impoverished under lower heating power and the operating stability is better under higher heating *** the inclination angle of 90°,the temperature at heating side decreases compared to ultra-pure water and the temperature at heating side decreases with the raising of MEPCM suspension mass *** heat transfer characteristic of the PHP is positively correlated with the inclination angle and the 90° is *** unfavorable effect of the inclination angle decreases with heating power *** the inclination angle is 90°,the PHP with MEPCM suspension at 1.0% of mass concentration has the lowest thermal transfer resistance and followed by ultra-pure water and MEPCM suspension at 0.5% of mass concentration has the highest thermal transfer *** the inclination angles are 60° and30°,the effect of gravity on the flow direction is reduced to 86.6% and 50% of that on the inclination angle of 90°,respectively,and the promoting effect of gravity on the working fluid is further weakened as the inclination angle further *** to the high viscosity of MEPCM suspension,the PHP with ultra-pure water has the lowest heat transfer *** the inclination angles is 60°,the thermal resistance with MEPCM suspension at0.5% of the mass concentration is lower than that at 1.0% at the heating power below 230 *** thermal resistance of MEPCM suspension tends to be simila

关键词： pulsating heat pipe(PHP) micro encapsulated phase change material(MEPCM) heat transfer characteristic inclination angle

A review on current development of thermophotovoltaic technology in heat recovery

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International Journal of Extreme Manufacturing 2024年第2期6卷 297-323页

作者： Shuni Chen Yanming Guo Qinghui pan Yong Shuai Ministry of Industry and Information Technology Key Laboratory of Aerospace Thermophysics School of Energy Science and EngineeringHarbin Institute of TechnologyHarbin 150001People’s Republic of China

The burning of fossil fuels in industry results in significant carbon emissions,and the heat generated is often not fully *** high-temperature industries,thermophotovoltaics(TPVs)is an effective method for waste heat *** review covers two aspects of high-efficiency TPV systems and industrial waste heat *** the system level,representative results of TPV complete the systems,while selective emitters and photovoltaic cells in the last decade are *** key points of components to improve the energy conversion efficiency are further analyzed,and the related micro/nano-fabrication methods are *** the application level,the feasibility of TPV applications in high-temperature industries is shown from the world waste heat utilization *** potential of TPV in waste heat recovery and carbon neutrality is illustrated with the steel industry as an example.

关键词： thermophotovoltaic waste heat recovery micro/nano-fabrication carbon neutrality

The Al_(2)O_(3)and Mn/Al_(2)O_(3)sorbents highly utilized in destructive sorption of NF_(3)

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Chinese Journal of Chemical Engineering 2024年第1期65卷 54-62页

作者： Yanfei pan Hejian Li Li Zheng Xiufeng Xu School of Chemistry and Chemical Engineering Yantai UniversityYantai 264005China

NF_(3)is commonly used as an etching and cleaning gas in semiconductor industry,however it is a strongly greenhouse ***,the destruction of disposal NF_(3)is an urgent task to migrate the greenhouse *** the technologies for NF_(3)abatement,the destructive sorption of NF_(3)over metal oxides sorbents is an effective ***,the search for a highly reactive and utilized sorbent for NF_(3)destruction is in great *** this work,AlOOH supported on carbon-sphere(AlOOH/CS)as precursors were synthesized hydrothermally and heat-treated to prepare the Al_(2)O_(3)*** influence of AlOOH/CS hydrothermal temperatures on the reactivity of derived Al_(2)O_(3)sorbents for NF_(3)destruction was investigated,and it is shown that the Al2O3 from AlOOH/CS hydro-thermalized at 120℃is superior to ***,the optimized Al_(2)O_(3)was covered by Mn(OH)x to prepare Mn/Al_(2)O_(3)sorbents via changing hydrothermal temperatures and Mn *** results show that the Mn/Al_(2)O_(3)sorbents are more utilized than bare Al_(2)O_(3)in NF_(3)destructive sorption due to the promotional effect of Mn_(2)O_(3)as surface layer on the fluorination of Al_(2)O_(3)as substrate,especially the optimal 5%Mn/Al2O3(160℃)exhibits a utilization percentage as high as 90.4%,and remarkably exceeds all the sorbents reported so *** findings are beneficial to develop more efficient sorbents for the destruction of NF_(3).

关键词： Greenhouse gas NF_(3)destructive sorption Sorbents Al_(2)O_(3) Mn/Al_(2)O_(3) Reactivity

Real-Time Intelligent Diagnosis of Co-frequency Vibration Faults in Rotating Machinery Based on Lightweight-Convolutional Neural Networks

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 264-282页

作者： Xin pan Xiancheng Zhang Zhinong Jiang Guangfu Bin Beijing Key Laboratory of Health Monitoring and Self-recovery for High-End Mechanical Equipment College of Mechanical and Electrical EngineeringBeijing University of Chemical TechnologyBeijing 100029China Key Laboratory of Engine Health Monitoring-Control and Networking(Ministry of Education) College of Mechanical and Electrical EngineeringBeijing University of Chemical TechnologyBeijing 100029China College of Mechanical Engineering Hunan University of Science and TechnologyXiangtan 411201China

The co-frequency vibration fault is one of the common faults in the operation of rotating equipment,and realizing the real-time diagnosis of the co-frequency vibration fault is of great significance for monitoring the health state and carrying out vibration suppression of the *** engineering scenarios,co-frequency vibration faults are highlighted by rotational frequency and are difficult to identify,and existing intelligent methods require more hardware conditions and are exclusively ***,Lightweight-convolutional neural networks(LW-CNN)algorithm is proposed in this paper to achieve real-time fault *** critical parameters are discussed and verified by simulated and experimental signals for the sliding window data augmentation *** on LW-CNN and data augmentation,the real-time intelligent diagnosis of co-frequency is ***,a real-time detection method of fault diagnosis algorithm is proposed for data acquisition to fault *** is verified by experiments that the LW-CNN and sliding window methods are used with high accuracy and real-time performance.

关键词： Co-frequency vibration Real-time diagnosis LW-CNN Data augmentation

Flow Field Simulation and Parameter Analysis of Hydraulic Unbalanced Bionic Self-recovery Actuator for Rotary Equipment

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Journal of Bionic Engineering 2024年第1期21卷 325-343页

作者： Wei Li Xin pan Dehong Ge Jinji Gao Key Laboratory of Engine Health Monitoring-Control and Networking of Ministry of Education Beijing University of Chemical TechnologyBeijing 100029China Beijing Key Laboratory of High-End Mechanical Equipment Health Monitoring and Self-Recovery Beijing University of Chemical TechnologyBeijing 100029China

The rotor is the most important component of rotating machinery,and the vibration produced by its mass unbalance has a serious influence on the secure and steady operation of the machine,so an effective online suppression technology is urgently needed.A new hydraulic unbalanced bionic self-recovery system is introduced,imitating the way of manually repairing faulty *** accomplish the effect of actuator mass redistribution,the technology employs pressurized air to drive the quantitative transfer of liquid in the reservoir cavity at opposite *** can complete the online adjustment of the equipment's balancing state and suppress the unbalanced vibration of equipment in real time,which gives the equipment the ability to maintain an autonomous health state and improve equipment *** composition and working principle of the system are introduced in detail,and the key performance parameters,such as the minimum running speed and the balancing liquid transfer speed,are analyzed *** fluid-solid coupling model of the actuator was established,and the two-phase flow from inside the hydraulic unbalanced bionic self-recovery actuator was simulated under multiple working conditions and the performance parameters were quantitatively analyzed.A balancing simulation test bed was built,and its effectiveness was verified by performance parameter tests and unbalanced bionic self-recovery *** experimental results show that the mass distribution adjustment of the balancing disk can be achieved using different viscosity balancing liquid,and the response of liquid viscosity 10 cSt is faster than that of liquid viscosity 100 cSt in the process of balancing liquid transfer,and the time is reduced by more than 75%;the system can reduce the simulated rotor amplitude from 18.3μm to 10.6μm online in real time,which provides technical support for the subsequent development of a new generation of bionic intelligent equipment.

关键词： Engineering self-recovery-Bionics Simulation analysis Self-recovery regulation

A reduced-order model for fast predicting ionized flows of hypersonic vehicles along flight trajectory

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Chinese Journal of Aeronautics 2024年第1期37卷 89-105页

作者： Jingchao ZHANG Chunsheng NIE Jinsheng CAI Shucheng pan School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Science and Technology on Space Physics Laboratory China Academy of Launch Vehicle TechnologyBeijing 100076China Institute of Extreme Mechanics Northwestern Polytechnical UniversityXi’an 710072China

An improved Reduced-Order Model(ROM)is proposed based on a flow-solution preprocessing operation and a fast sampling strategy to efficiently and accurately predict ionized hypersonic *** ROM is generated in low-dimensional space by performing the Proper Orthogonal Decomposition(POD)on snapshots and is coupled with the Radial Basis Function(RBF)to achieve fast prediction ***,due to the disparate scales in the ionized flow field,the conventional ROM usually generates spurious negative ***,this issue is addressed by performing flow-solution preprocessing in logarithmic space to improve the conventional ***,extra orthogonal polynomials are introduced in the RBF interpolation to achieve additional improvement of the prediction *** addition,to construct high-efficiency snapshots,a trajectory-constrained adaptive sampling strategy based on convex hull optimization is *** evaluate the performance of the proposed fast prediction method,two hypersonic vehicles with classic configurations,i.e.a wave-rider and a reentry capsule,are used to validate the proposed *** two cases show that the proposed fast prediction method has high accuracy near the vehicle surface and the free-stream region where the flow field is *** with the conventional ROM prediction,the prediction results are significantly improved by the proposed method around the discontinuities,*** shock wave and the ionized *** a result,the proposed fast prediction method reduces the error of the conventional ROM by at least 45%,with a speedup of approximately 2.0×105compared to the Computational Fluid Dynamic(CFD)*** test cases demonstrate that the method developed here is efficient and accurate for predicting ionized hypersonic flows.

关键词： Reduced-order model Radial basis function Constrained sampling Transfer function Fast flow prediction Ionized hypersonic flows