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Journal of Systems Engineering and Electronics 2023年第6期34卷 1490-1500页

作者： SUN Shili LIU Shuai WANG jun YAN Fenggang JIN ming School of Information Science and Engineering Harbin Institute of TechnologyWeihai 264209China

The conformal array can make full use of the aperture,save space,meet the requirements of aerodynamics,and is sensitive to polarization *** has broad application prospects in military,aerospace,and communication *** joint polarization and direction-of-arrival(DOA)estimation based on the conformal array and the theoretical analysis of its parameter estimation performance are the key factors to promote the engineering application of the conformal *** solve these problems,this paper establishes the wave field signal model of the conformal ***,for the case of a single target,the cost function of the maximum likelihood(ML)estimator is rewritten with Rayleigh quotient from a problem of maximizing the ratio of quadratic forms into those of minimizing quadratic *** this basis,rapid parameter estimation is achieved with the idea of manifold separation technology(MST).Compared with the modified variable projection(MVP)algorithm,it reduces the computational complexity and improves the parameter estimation ***,the MST is used to solve the partial derivative of the steering ***,the theoretical performance of ML,the multiple signal classification(MUSIC)estimator and Cramer-rao bound(CRB)based on the conformal array are derived respectively,which provides theoretical foundation for the engineering application of the conformal ***,the simulation experiment verifies the effectiveness of the proposed method.

关键词： conformal array maximum likelihood(ML)estimator manifold separation technology(MST) parameter estimation Cramer-rao bound(CRB).

Numerical study on the hydrodynamics behavior of a central insert microchannel

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Chinese Journal of Chemical Engineering 2023年第1期53卷 361-373页

作者： Yongbo Zhou Yang Jin jun Li Qinyan Wang ming Chen Engineering Research Center of Comprehensive Utilization and Clean Processing of Phosphorus Resources School of Chemical EngineeringSichuan UniversityChengdu 610065China

In this work, the computational fluid dynamics method is used to study the liquid hydrodynamics behavior in the microchannel without central insert(MC1) and the central insert microchannel(MC2), respectively. The maximum deviation between simulation and experiment is 24%. The formations of flow patterns are explained based on contours and force analysis where the flow pattern maps are established by two-phase flow rate. The effects of aqueous phase viscosity and two-phase flow rate on the characteristic sizes of each flow pattern are also explored. Specifically, four unconventional flow patterns are found in MC2, namely the unique droplet flow, the unique slug flow, the unique coarse annular flow and the unique film annular flow. Though the insert occupies part of the channel, the pressure difference in the channel is significantly reduced compared with MC1. Moreover, the insert significantly changes the formation velocity range of each flow pattern, greatly broadens the formation range of annular flow and also has an important influence on the characteristic size of the flow pattern. The organic-phase dimensionless axial size(Lo/W) and the dimensionless radial size(Do/W) of the droplet(slug) are negatively related to the aqueous-phase viscosity(μa) and flow rate(ua). The Do/W of the annular is negatively correlated with μaand positively correlated with organic-phase flow rate(uo). This study provides direct numerical evidence that the insert is key to the formation of bicontinuous phase flow pattern, as well as further strengthens our understanding of the flow characteristics and optimization design of insert microchannels.

关键词： Microchannel Process intensification Computational fluid dynamics Liquid–liquid flow pattern Central insert

Wind-tunnel experimental studies of the spatial snow distribution over grass and bush surfaces

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Journal of Hydrodynamics 2022年第1期34卷 85-93页

作者： Guang Li jun-ming Qin Hong-xiang Yu Ning Huang Key Laboratory of Mechanics on Disaster and Environment in Western China The Ministry of Education of ChinaLanzhou UniversityLanzhou730000China School of Civil Engineering and Mechanics Lanzhou UniversityLanzhou730000China College of Atmospheric Science Lanzhou UniversityLanzhou730000China School of Architecture Civil and Environmental EngineeringSwiss Federal Institute of Technology LausanneLausanneSwitzerland

The snow is one of the most important water resources in grassland in northern and western China, while the wind blowing snow due to the strong wind there is a common phenomenon, which can lead to heavy disasters to harm the local animal husbandry and transportation. A reasonable arrangement of the snow protection forests is one of the most economical and effective methods to prevent the wind blowing snow, and a great number of investigations were carried out for its wind block effects. However, the deposition patterns of the snowfall and the blowing snow in the forests are still largely unknown. In this study, the wind tunnel experiments are performed to investigate the influences of the vegetation (grass and bush) on the wind speed profiles and the spatial distribution of the accumulated snow, by using the bran as the snow substitute. The snow blocking abilities of two bush models are analyzed to show the effects of different coverages. The results show that the grass and the bush have different effects on the wind speed profiles, and the snow-blocking abilities of the vegetation and the resulting spatial distribution are determined by the amount of the snowfall, the wind speed, and the height and the coverage of the vegetation. For the engineering design, if the snow is required on the windward side of the vegetation or in the vegetation, the densely arranged forest belts are needed, if the snow is required to accumulate on the leeward side of the vegetation, the sparse forest belts can be used. This work would be helpful as a reference to the reasonable arrangement of the snow-protection forests in pastoral areas.

关键词： Wind tunnel experiment wind speed profile vegetation snow-protection forest snow blocking ability

SVD-Based Low-Complexity Methods for Computing the Intersection of K≥2 Subspaces

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Chinese Journal of Electronics 2019年第2期28卷 430-436页

作者： YAN Fenggang WANG jun LIU Shuai JIN ming SHEN Yi School of Information and Electrical Engineering Harbin Institute of Technology at Weihai School of Astronautics Harbin Institute of Technology

Given the orthogonal basis(or the projections) of no less than two subspaces in finite dimensional spaces, we propose two novel algorithms for computing the intersection of those subspaces. By constructing two matrices using cumulative multiplication and cumulative sum of those projections, respectively, we prove that the intersection equals to the null spaces of the two matrices. Based on such a mathematical fact,we show that the orthogonal basis of the intersection can be efficiently computed by performing singular value decompositions on the two matrices with much lower complexity than most state-of-the-art methods including alternate projection method. Numerical simulations are conducted to verify the correctness and the effectiveness of the proposed methods.

关键词： Orthogonal projection Cumulative sum Cumulative multiplication Singular value decomposition Intersection

Fast and accurate covariance matrix reconstruction for adaptive beamforming using Gauss-Legendre quadrature

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Journal of Systems Engineering and Electronics 2021年第1期32卷 38-43页

作者： LIU Shuai ZHANG Xue YAN Fenggang WANG jun JIN ming School of Information Science and Engineering Harbin Institute of TechnologyWeihai 264209China

Most of the reconstruction-based robust adaptive beamforming(RAB)algorithms require the covariance matrix reconstruction(CMR)by high-complexity integral computation.A Gauss-Legendre quadrature(GLQ)method with the highest algebraic precision in the interpolation-type quadrature is proposed to reduce the *** interference angular sector in RAB is regarded as the GLQ integral range,and the zeros of the threeorder Legendre orthogonal polynomial is selected as the GLQ ***,the CMR can be efficiently obtained by simple summation with respect to the three GLQ nodes without *** new method has significantly reduced the complexity as compared to most state-of-the-art reconstruction-based RAB techniques,and it is able to provide the similar performance close to the *** advantages are verified by numerical simulations.

关键词： robust adaptive beamforming(RAB) covariance matrix reconstruction(CMR) Gauss-Legendre quadrature(GLQ) complexity reduction

Cloaking Region Based Passenger Privacy Protection in Ride-Hailing Systems

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Journal of Computer Science & Technology 2020年第3期35卷 629-646页

作者： Yubin Duan Guo-Ju Gao ming-jun Xiao Jie Wu Department of Computer and Information Sciences Temple UniversityPennsylvania 19122U.S.A. School of Computer Science and Technology University of Science and Technology of ChinaHefei 230036China

With the quick development of the sharing economy,ride-hailing services have been increasingly popular *** the service provides convenience for users,one concern from the public is whether the location privacy of passengers would be *** providers(SPs)such as Didi and Uber need to acquire passenger and driver locations before they could successfully dispatch passenger *** protect passengers’privacy based on their requirements,we propose a cloaking region based order dispatch *** our scheme,a passenger sends the SP a cloaking region in which his/her actual location is not *** trade-off of the enhanced privacy is the loss of social welfare,i.e.,the increase in the overall pick-up *** optimize our scheme,we propose to maximize the social welfare under passengers’privacy *** investigate a bipartite matching based approach.A theoretical bound on the matching performance under specific privacy requirements is *** passengers’privacy,we allow drivers to set up their maximum pick-up distance in our extended *** extended scheme could be applied when the number of drivers exceeds the number of ***,the global matching based scheme does not consider the interest of each individual *** passengers with low privacy requirements may be matched with drivers far from *** this end,a pricing scheme including three strategies is proposed to make up for the individual loss by allocating discounts on their riding *** experiments on both real-world and synthetic datasets show the efficiency of our scheme.

关键词： order dispatch pricing privacy ride-hailing

Design and Imaging Application of Room-Temperature Terahertz Detector with Micro-Bolometer Focal Plane Array

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Journal of Electronic Science and Technology 2016年第2期14卷 98-102页

作者： jun Wang jun Gou Zhi-ming Wu Ya-Dong Jiang School of Optoelectronic Information University of Electronic Science and Technology of China

Room-temperature terahertz （THz） detectors indicate a great potential in the imaging application because of their real-time, compact bulk, and wide spectral band responding characteristics. THz detectors with different dimensions based on a micro-bridge structure have been designed and fabricated to get optimized micro-bolometer parameters from the test results of membrane deformation. A nanostructured titanium （Ti） thin film absorber is integrated in the micro-bridge structure of the VOx micro-bolometer by a combined process of magnetron sputtering and reactive ion etching （RIE）, and its improvement of THz absorption is verified by an optical characteristics mesurement. Continuous-wave THz detection and imaging are demonstrated by using a 2.52 THz far infrared CO2 laser and a 320x240 vanadium oxide micro-bolometer focal plane array with an optimized cell structure. With this detecting system, THz imaging of metal concealed in a wiping cloth and an envelope is demonstrated, respectively.

关键词： Index Terms---Focal plane array micro-bolometer structure real-time imaging room temperatureterahertz detector

Coercivity enhancement of hot-deformed Nd-Fe-B magnets with Pr-Cu alloy addition

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Rare Metals 2023年第4期42卷 1403-1407页

作者： jun-ming Wang Zhao-Hui Guo Zheng Jing Xiao Du Neng-jun Yu Meng-Yu Li ming-Gang Zhu Wei Li Division of Functional Materials Central Iron&Steel Research InstituteBeijing100081China

Effects of low-melting Pr-Cu alloy addition on the microstructure and magnetic properties of the hot-deformation Nd-Fe-B magnets were investigated.A small amount of Pr-Cu addition enhances the coercivity of the hot-deformation Nd-Fe-B magnets *** coercivity of the hotdeformation Nd-Fe-B magnets with 4.0 wt%Pr_(85)Cu_(15)addition increases to 1271 kA·m^(-1),75.69%higher than that of Pr-Cu-free magnet(723 kA·m^(-1)),and then decreases with5 wt%Pr_(85)Cu_(15)*** is observed that there a uniform RE-rich phase is formed wrapping the Nd2Fe14B main phase in the sample with 4.0%Pr_(85)Cu_(15)addition by scanning electron microscopy(SEM),which promotes the *** angular dependence of coercivity for the hot-deformation Nd-Fe-B magnets indicates that the coercivity mechanism is nucleation combined with domain wall *** domain wall pinning is weakened,while the nucleation is enhanced after Pr-Cu ***,intrinsic coercivity,and maximum magnetic energy product of the original Nd-Fe-B magnet are 1.45 T,723 kA·m^(-1),and 419.8 kJ·m^(-3),respectively,and those of the sample with 4.0%Pr_(85)Cu_(15)alloy addition are 1.30 T,1271 kA·m^(-1),and 330.0 kJ·m^(-3),respectively.

关键词： Nd-Fe-B Low-melting alloy Hot-deformation Microstructure Coercivity mechanism

Characterization the influences of diodes to piezoelectric energy harvester

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International Journal of Smart and Nano Materials 2018年第3期9卷 151-166,I0001页

作者： ming Yuan Ziping Cao jun Luo School of Automation Nanjing University of Posts and TelecommunicationsNanjingP.R.China School of Telecommunications and Information Engineering Nanjing University of Posts and TelecommunicationsNanjingP.R.China

This study discloses the diode’s influences on the piezoelectric energy harvesting *** piezoelectric-based energy harvesting system plays an important role in scavenging environment vibration energy into electrical energy,which can be utilized by low-power electronic *** respect to the interface circuit,a full-wave bridge circuit is usually needed to rectify the alternating current(AC)signal into a direct current(DC)*** full-wave bridge is composed of four diodes,whose characteristics may influence the harvested power ***,in this paper,the diodes’properties and influences on the energy harvesting performance are analyzed and presented via simulation and experimental *** is found the harvested energy has close relationship with the diode *** the high source impedance case,diode with low reverse leakage current is *** the low source impedance case,diode with low forward voltage drop is *** corresponding experimental study is carried out via a piezoelectric beam,which shows that the measured harvested power differences can almost be up to 800%for the same test structure.

关键词： Piezoelectric energy harvesting diode’s influence power evaluation

Recent evidence for activity-dependent initiation of sympathetic sprouting and neuropathic pain

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生理学报 2008年第5期60卷 617-627页

作者： jun-ming ZHANG Judith A. Strong Department of Anesthesiology University of Cincinnati College of Medicine 231 Albert Sabin Way Cincinnati OH 45267-0531 USA

Traumatic injury or inflammatory irritation of the peripheral nervous system often leads to persistent pathophysiological pain *** has been well-documented that,after peripheral nerve injury or inflammation,functional and anatomical alterations sweep over the entire peripheral nervous system including the peripheral nerve endings,the injured or inflamed afferent fibers,the dorsal root ganglion(DRG),and the central afferent terminals in the spinal *** all the changes,ectopic discharge or spontaneous activity of primary sensory neurons is of great clinical interest,as such discharges doubtless contribute to the develop-ment of pathological pain states such as neuropathic *** key sources of abnormal spontaneous activity have been identified following peripheral nerve injury:the injured afferent fibers(neuroma) leading to the DRG,and the DRG *** purpose of this review is to provide a global account of the abnormal spontaneous activity in various animal models of *** attention is focused on the consequence of peripheral nerve injury and localized ***,mechanisms involved in the generation of spontaneous activity are also reviewed;evidence of spontaneous activity in contributing to abnormal sympathetic sprouting in the axotomized DRG and to the initiation of neuropathic pain based on new findings from our research group are *** improved understanding of the causes of spontaneous activity and the origins of neuropathic pain should facilitate the development of novel strategies for effective treatment of pathological pain.

关键词：活动依赖性神经性疼痛病症临床分析