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Simultaneous measurement of velocity profile and liquid film thickness in horizontal gas–liquid slug flow by using ultrasonic Doppler method 被引量:1
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作者 Lusheng Zhai Bo Xu +1 位作者 Haiyan Xia Ningde Jin 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第6期323-340,共18页
Horizontal gas-liquid two-phase flows widely exist in chemical engineering,oil/gas production and other important industrial processes.Slug flow pattern is the main form of horizontal gas-liquid flows and characterize... Horizontal gas-liquid two-phase flows widely exist in chemical engineering,oil/gas production and other important industrial processes.Slug flow pattern is the main form of horizontal gas-liquid flows and characterized by intermittent motion of film region and slug region.This work aims to develop the ultrasonic Doppler method to realize the simultaneous measurement of the velocity profile and liquid film thickness of slug flow.A single-frequency single-channel transducer is adopted in the design of the field-programmable gate array based ultrasonic Doppler system.A multiple echo repetition technology is used to improve the temporal-spatial resolution for the velocity profile.An experiment of horizontal gas-liquid two-phase flow is implemented in an acrylic pipe with an inner diameter of 20 mm.Considering the aerated characteristics of the liquid slug,slug flow is divided into low-aerated slug flow,high-aerated slug flow and pseudo slug flow.The temporal-spatial velocity distributions of the three kinds of slug flows are reconstructed by using the ultrasonic velocity profile measurement.The evolution characteristics of the average velocity profile in slug flows are investigated.A novel method is proposed to derive the liquid film thickness based on the instantaneous velocity profile.The liquid film thickness can be effectively measured by detecting the position and the size of the bubbles nearly below the elongated gas bubble.Compared with the time of flight method,the film thickness measured by the Doppler system shows a higher accuracy as a bubble layer occurs in the film region.The effect of the gas distribution on the film thickness is uncovered in three kinds of slug flows. 展开更多
关键词 Gas–liquid flow Complex fluids measurement Ultrasonic Doppler velocity profile Liquid film thickness
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Measuring the Internal Velocity of Debris Flows Using Impact Pressure Detecting in the Flume Experiment 被引量:12
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作者 YANG Hongjuan WEI Fangqiang +4 位作者 HU Kaiheng Sergey CHERNOMORETS HONG Yong LI Xiaoyu XIE Tao 《Journal of Mountain Science》 SCIE CSCD 2011年第2期109-116,共8页
Measuring the internal velocity of debris flows is very important for debris flow dynamics research and designing debris flow control works. However, there is no appropriate method for measuring the internal velocity ... Measuring the internal velocity of debris flows is very important for debris flow dynamics research and designing debris flow control works. However, there is no appropriate method for measuring the internal velocity because of the destructive power of debris flow process. In this paper, we address this problem by using the relationship between velocity and kinetic pressure, as described by surface velocity and surface kinetic pressure data. Kinetic pressure is the difference of impact pressure and static pressure. The former is detected by force sensors installed in the flow direction at the sampling section. Observations show that static pressure can be computed using the formula for static water pressure by simply substituting water density for debris flow density. We describe the relationship between surface velocity and surface kinetic pressure using data from seven laboratory flume experiments. It is consistent with the relationship for single phase flow, which is the measurement principle of the Pitot tube. 展开更多
关键词 Internal velocity measurEMENT Debris flow Impact pressure
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Simutaneous radar imaging and velocity measuring with step frequency waveforms 被引量:4
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作者 Yuan Haotian Wen Shuliang Cheng Zhen 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第4期741-747,共7页
The principle and method of both radar target imaging and velocity measurement simultaneously based on step frequency waveforms is presented. Velocity compensation is necessary in order to obtain the good High resolut... The principle and method of both radar target imaging and velocity measurement simultaneously based on step frequency waveforms is presented. Velocity compensation is necessary in order to obtain the good High resolution range profile since this waveform is greatly sensitive to the Doppler shift. The velocity measurement performance of the four styles is analyzed with two pulse trains consisted of positive and negative step frequency waveforms. The velocity of targets can be estimated first coarsely by using the pulse trains with positive-positive step frequency combination, and then fine by positive-negative combination. Simulation results indicate that the method can accomplish the accurate estimation of the velocity with efficient computation and good anti-noise performance and obtain the good HRRP simultaneously. 展开更多
关键词 high resolution radar step frequency waveform velocity measuring high resolution range profile.
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Measuring the velocity of sand particles in an air/particle two-phase flow:A comparison of several commonly used methods 被引量:2
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作者 Zhibao Dong GuangQiang Qian WanYin Luo HongTaoWang 《Research in Cold and Arid Regions》 2010年第3期185-197,共13页
The velocity of blown sand particles is an important parameter in aeolian movement (a special case of gas particle two-phase flow) and has ever been a topic of interest. At present, several techniques have been appl... The velocity of blown sand particles is an important parameter in aeolian movement (a special case of gas particle two-phase flow) and has ever been a topic of interest. At present, several techniques have been applied in measuring velocity of the blown sand particles. This paper reviews the measurement results of several commonly used methods: photoelectric cell method, high-speed photographic method, Particle Dynamics Analyzer (PDA) method and Particle Image Velocimetry (PIV) method. Photoelectric cell method, high-speed photograph method and PDA method are useful in studying the velocity distribution of particles. PIV is a whole-flow-field technique and a useful tool to study the average velocity field in a target area. These methods got some similar results but considerable differences also exist. They have come to similar conclusions on the velocity distributions at a single height but direct measurement results with respect to the velocity distribution very close to the surface are still scarce except some PDA results. The magnitude of measured mean particle velocity differs greatly. The relationship obtained by different methods between mean particle velocity and wind velocity, particle size and possibly other influencing factors also differs considerably. Although several authors have proposed similar power functions to describe the variation with height of the mean particle velocity, the predicted results have wide differences. Each technique is based on some unique principles, and has its advantages and disad- vantages. To make full use of different techniques, a lot of work needs be done to validate them. Developing a reliable technique to measure the velocity of blown particles is still a necessary task in aeolian research. 展开更多
关键词 aeolian transport velocity of particles measurement techniques
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Velocity Correction and Measurement Uncertainty Analysis of Light Screen Velocity Measuring Method 被引量:2
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作者 郑宾 左兆陆 侯文 《Defence Technology(防务技术)》 SCIE EI CAS 2012年第4期236-239,共4页
Light screen velocity measuring method with unique advantages has been widely used in the velocity measurement of various moving bodies.For large air resistance and friction force which the big moving bodies are subje... Light screen velocity measuring method with unique advantages has been widely used in the velocity measurement of various moving bodies.For large air resistance and friction force which the big moving bodies are subjected to during the light screen velocity measuring,the principle of velocity correction was proposed and a velocity correction equation was derived.A light screen velocity measuring method was used to measure the velocity of big moving bodies which have complex velocity attenuation,and the better results were gained in practical tests.The measuring uncertainty after the velocity correction was calculated. 展开更多
关键词 火炮 测试技术 测试设备 试验
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Method for Measuring Velocity of Warhead Fragments Based on Photoelectric Detection 被引量:8
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作者 倪晋平 杨雷 《Defence Technology(防务技术)》 SCIE EI CAS 2007年第4期275-280,共6页
For measuring velocity and impacting position of single fragment of warhead,a non-contact measuring method is proposed,in which a six-light-screen array,a position indicator,a multi-channel chronograph and a computer ... For measuring velocity and impacting position of single fragment of warhead,a non-contact measuring method is proposed,in which a six-light-screen array,a position indicator,a multi-channel chronograph and a computer are used.The principle of measurement is described.The key device of the system is a light screen array sensor which consists of six light screens allocated with certain geometrical parameters.When the fragment flies through the light screen array,the time of passing through each of the screens is recorded by the multi-channel chronograph.According to the time data and the geometrical parameters of the array,the velocity vector and the location of the fragment can be calculated immediately.The presented method can be used to locate the fragment and to measure the real velocity on its flying direction.It can also be used to measure the velocity of a fragment swarm after the system is engineered further. 展开更多
关键词 弹头 速度 方向 光电检测 轨迹
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UAV Velocity Measurement for Ground Moving Target 被引量:2
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作者 黄大庆 徐诚 +1 位作者 韩伟 王东振 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2015年第1期9-15,共7页
To satisfy the demand of measuring the velocity of ground moving target through unmanned aerial vehicle(UAV)electro-optical platform,two velocity measurement methods are proposed.Firstly,a velocity measurement method ... To satisfy the demand of measuring the velocity of ground moving target through unmanned aerial vehicle(UAV)electro-optical platform,two velocity measurement methods are proposed.Firstly,a velocity measurement method based on target localization is derived,using the position difference between two points with the advantages of easy deployment and realization.Then a mathematical model for measuring target velocity is built and described by 15 variables,i.e.UAV velocity,UAV attitude angular rate,camera direction angular rate and so on.Moreover,the causes of velocity measurement error are analyzed and a formula is derived for calculating the measurement error.Finally,the simulation results show that angular rate error has a strong influence on the velocity measurement accuracy,especially the UAV pitch angular rate error,roll angular rate error and the camera angular altitude rate error,thus indicating the direction for improving velocity measurement precision. 展开更多
关键词 unmanned aerial vehicle(UAV) target velocity measurement target localization velocity measurement error
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Velocity of detonation measurement and fragmentation analysis to evaluate blasting efficacy 被引量:3
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作者 Eugie Kabwe 《Journal of Rock Mechanics and Geotechnical Engineering》 CSCD 2018年第3期523-533,共11页
In holes, the measurement of the velocity of detonation(VOD) helps in comparing and evaluating relative performance of explosives. In this paper a blast performance assessment was conducted based on the results obta... In holes, the measurement of the velocity of detonation(VOD) helps in comparing and evaluating relative performance of explosives. In this paper a blast performance assessment was conducted based on the results obtained from the steady state VOD measurement of emulsion explosives HEF100 and degree of blast fragmentation conducted on an open pit blast. The aim of this study was to compare the steady state VOD measured in the field and the published VOD of HEF100 under ideal laboratory conditions and ascertain its efficacy. In the trial, a resistance wire continuous VOD measurement system connected to a SpeedVOD was employed to measure and record the steady state VOD values from five different blast holes. Furthermore, a post fragmentation analysis was conducted using the existing fragmentation models and an image processing software. The steady state VOD values recorded from the field ranged between 4981 m/s to 5387 m/s consistent with the published VOD subjected to ideal laboratory conditions and the analyzed fragmentation size distribution indicates that 90% of the blasted muck pile was within the allowable and optimal 700 mm passing size. 展开更多
关键词 BLASTING Bulk emulsion Explosives In-hole continuous measurement velocity of detonation (VOD)
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Particle Velocity Sensor and Its Application in Near-Field Noise Scanning Measurement 被引量:2
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作者 Xuecong Zhang Di Liu +3 位作者 Xiaoguang Li Yunfei Liu Qijie Tu Yu Zhou 《Journal of Applied Mathematics and Physics》 2019年第11期2902-2908,共7页
The Particle Velocity Sensor (PVS) is a kind of acoustic transducer which measures the particle velocity directly with figure-of-eight directivity. This paper proposes a near-field noise scanning technology based on t... The Particle Velocity Sensor (PVS) is a kind of acoustic transducer which measures the particle velocity directly with figure-of-eight directivity. This paper proposes a near-field noise scanning technology based on the research of PVS, pressure-particle velocity (P-U) probe, and its application in noise source identification. Firstly, the principle and characteristics of PVS are presented. Secondly, a P-U probe is designed on the basis of PVS development. Finally, the noise measurement experiment for a single source is arranged and conducted. The result shows that the proposed P-U probe performs well in near-field noise source identification and localization. 展开更多
关键词 PARTICLE velocity Pressure-Particle velocity PROBE NEAR-FIELD Noise SCANNING measurEMENT Acoustic Imaging
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High sampling-rate measurement of turbulence velocity fluctuations in Mach 1.8 Laval jet using interferometric Rayleigh scattering 被引量:4
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作者 Li Chen Fu-Rong Yang +4 位作者 Tie Su Wei-Yi Bao Bo Yan Shuang Chen Ren-Bing Li 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第2期341-344,共4页
Interferometric Rayleigh scattering diagnostic technique for the time-resolved measurement of flow velocity is studied. Theoretically, this systematic velocity-measured accuracy can reach up to 1.23 m/s. Measurement a... Interferometric Rayleigh scattering diagnostic technique for the time-resolved measurement of flow velocity is studied. Theoretically, this systematic velocity-measured accuracy can reach up to 1.23 m/s. Measurement accuracy is then evaluated by comparing with hot wire anemometry results. Moreover, the distributions of velocity and turbulence intensity in a supersonic free jet from a Laval nozzle with a Mach number of 1.8 are also obtained quantitatively. The sampling rate in this measurement is determined to be approximately 10 k Hz. 展开更多
关键词 Fabry–Pérot interferometer Rayleigh scattering time-resolved velocity measurement turbulence
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Micro-failure process and failure mechanism of brittle rock under uniaxial compression using continuous real-time wave velocity measurement 被引量:3
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作者 WU Zhi-jun WANG Zhi-yang +2 位作者 FAN Li-feng WENG Lei LIU Quan-sheng 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第2期556-571,共16页
In this study,the micro-failure process and failure mechanism of a typical brittle rock under uniaxial compression are investigated via continuous real-time measurement of wave velocities.The experimental results indi... In this study,the micro-failure process and failure mechanism of a typical brittle rock under uniaxial compression are investigated via continuous real-time measurement of wave velocities.The experimental results indicate that the evolutions of wave velocities became progressively anisotropic under uniaxial loading due to the direction-dependent development of micro-damage.A wave velocity model considering the inner anisotropic crack evolution is proposed to accurately describe the variations of wave velocities during uniaxial compression testing.Based on which,the effective elastic parameters are inferred by a transverse isotropic constitutive model,and the evolutions of the crack density are inversed using a self-consistent damage model.It is found that the propagation of axial cracks dominates the failure process of brittle rock under uniaxial loading and oblique shear cracks develop with the appearance of macrocrack. 展开更多
关键词 elastic wave velocity brittle rock failure uniaxial compression test continuous real-time measurement anisotropic damage evolution theory and modelling
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Application of Spatial Filtering Techniques in the Measurement of the Velocity 被引量:1
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作者 LIPing MABaoming 《Semiconductor Photonics and Technology》 CAS 1998年第1期56-61,共6页
As one of the interesting optical techniques for measurements of the velocity,the spatial filtering method is treated briefly in this paper.We shown theoretical analysis and calculation of spatial filtering velocimetr... As one of the interesting optical techniques for measurements of the velocity,the spatial filtering method is treated briefly in this paper.We shown theoretical analysis and calculation of spatial filtering velocimetry,and discussed two-dimensional measurements of the velocity.About the data processing,we used A/D conversion and interfaced with a microcomputer,so that the data can be processed automatically by the microcomputer.The preliminary experiment was performed and the experimental results show the usefulness of the present method for measurements of the velocity. 展开更多
关键词 measurEMENT Spatial Filtering velocity
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Velocity Measurement and Freezing Technology of Multi-shot Pellet on HL-1M Tokamak 被引量:1
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作者 李波 李立 +6 位作者 肖正贵 王明旭 刘德权 郑银甲 冯震 王明建 徐小桥 《Plasma Science and Technology》 SCIE EI CAS CSCD 2001年第5期971-976,共6页
A measuring system for high-speed hydrogen ice pellet was introduced in this paper and the photographing of flying pellet taken therein. With the system, a pellet (minimum size of φ 0.3 mm) velocity (ranging from 50 ... A measuring system for high-speed hydrogen ice pellet was introduced in this paper and the photographing of flying pellet taken therein. With the system, a pellet (minimum size of φ 0.3 mm) velocity (ranging from 50 m/s to 2500 m/s) can be measured in the HL-1M tokamak fueling experiments. By analyzing photographs and the conditions of frozen pellets (including gas supply, gas replenishment, temperature controlling etc), the pellet-freezing technology is summarized in the paper. 展开更多
关键词 velocity measurement and Freezing Technology of Multi-shot Pellet on HL-1M Tokamak HL
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Measurement of the Plasma Rotation Velocity by Using Visible Spectrum on HL-1M Mokamak 被引量:1
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作者 罗俊林 李伟 +3 位作者 王恩耀 董贾福 唐年益 刘泽田 《Plasma Science and Technology》 SCIE EI CAS CSCD 2001年第2期683-690,共8页
The plasma rotation velocity were measured in HL-1M with Doppler shifts of CⅢ、 C Ⅱ、 O Ⅱ and H. line by a SKD high resolution spectrometer. The effects .of density' hydrogen pellet injection and carbon impuri... The plasma rotation velocity were measured in HL-1M with Doppler shifts of CⅢ、 C Ⅱ、 O Ⅱ and H. line by a SKD high resolution spectrometer. The effects .of density' hydrogen pellet injection and carbon impurities injected by laser-blow-off on toroidal(V) and poloidal (Vθ)rotation velocity have been observed. The Vθ measured from H. line is only half of that from C Ⅱ impurity line. 展开更多
关键词 measurement of the Plasma Rotation velocity by Using Visible Spectrum on HL-1M Mokamak HL
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Velocity measurement technique for high-speed targets based on digital fine spectral line tracking
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作者 Wen Shuliang Yuan Qi 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2006年第1期6-12,共7页
Target vdocity and acceleration are two of the most important features for identification of warheads and decoys in ballistic missile defense phased array radar systems. Velocity compensation is also the necessary ste... Target vdocity and acceleration are two of the most important features for identification of warheads and decoys in ballistic missile defense phased array radar systems. Velocity compensation is also the necessary step for one-dimensional range profile imaging. According to the high-vdocity characteristics of ballistic objects and the low data rate of phased array radars with multiple target tracking, a fine spectral line digital velocity tracking frame is presented and a new method is developed to extract velocity error and resolve the velocity ambiguity in the measurement loop. Simulation results demonstrate the effectiveness of the proposed technique. 展开更多
关键词 radar tracking radial velocity measurement velocity error extraction velocity ambiguity
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Simultaneous density and velocity measurements in a supersonic turbulent boundary layer
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作者 何霖 易仕和 +2 位作者 田立丰 陈植 朱杨柱 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第2期328-334,共7页
A novel technique for simultaneous measurements of instantaneous whole-field density and velocity fields of supersonic flows has been developed.The density measurement is performed based on the nano-tracer planar lase... A novel technique for simultaneous measurements of instantaneous whole-field density and velocity fields of supersonic flows has been developed.The density measurement is performed based on the nano-tracer planar laser scattering(NPLS) technique,while the velocity measurement is carried out using particle image velocimetry(PIV).The present experimental technique has been applied to a flat-plate turbulent boundary layer at Mach 3,and the measurement accuracy of the density and velocity are discussed.Based on this new technique,the Reynolds stress distributions were also obtained,demonstrating that this is an effective means for measuring Reynolds stresses under compressible conditions. 展开更多
关键词 simultaneous measurements DENSITY velocity Reynolds stress
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Reliability analysis of in-situ stress measurement using circumferential velocity anisotropy
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作者 Jiandong Liu1, 2, Luhe Shen1, 2, Juan Jin1, 2 1 Key Laboratory of Oil and Gas Reservoirs, China National Petroleum Corporation, Beijing, 100083, China 2 PetroChina Research Institute of Petroleum Exploration and Development, Beijing, 100083, China 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE 2011年第S1期457-460,共4页
In-situ stress measurement for deep reservoir formation is difficult in terms of security, reliability and technique. Acoustic velocity anisotropy test is a basic method for stress measurement of rock cores, which is ... In-situ stress measurement for deep reservoir formation is difficult in terms of security, reliability and technique. Acoustic velocity anisotropy test is a basic method for stress measurement of rock cores, which is based on the distribution of acoustic velocity in different directions around rock cores. The heterogeneity of core samples, such as fractures and gravel contained, can also lead to wave velocity anisotropy. Therefore, the corresponding reliability evaluation method is established to exclude some other anisotropy factors caused by non-tectonic stresses. In this paper, the reliability of testing results is evaluated from three aspects, i.e. phase difference, anisotropy index and waveform, to remove the factors caused by non-tectonic stresses. 展开更多
关键词 acoustic velocity measurement wave velocity anisotropy in-situ stress measurement
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High-Precision Wideband Phase-Derived Velocity Measurement for Micro-Motion Extraction
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作者 Yuan Jiang Huayu Fan +1 位作者 Quanhua Liu Xinliang Chen 《Journal of Beijing Institute of Technology》 EI CAS 2017年第1期106-114,共9页
A phase-derived velocity measurement method is proposed in a wideband coherent system,based on a precise echo model considering the inner pulse Doppler effect caused by fast moving targets.The Cramer-Rao low band of v... A phase-derived velocity measurement method is proposed in a wideband coherent system,based on a precise echo model considering the inner pulse Doppler effect caused by fast moving targets.The Cramer-Rao low band of velocity measurement precision is deduced,demonstrating the high precision of the proposed method.Simulations and out-field experiments further validate the effectiveness of the proposed method in high-precision measurement and micro-motion extraction for targets with weak reflection intensity.Compared with the long-time integration approaches for velocity measurement,the phase-derived method is easy to implement and meets the requirement for high data rate,which makes it suitable for micro-motion feature extraction in wideband systems. 展开更多
关键词 phase-derived velocity measurement micro-motion extraction wideband coherent sys-tem high-precision measurement
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Asymptotic bounded consensus tracking of double-integrator multi-agent systems with bounded-jerk target based on sampled-data without velocity measurements
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作者 Shuang-Shuang Wu Zhi-Hai Wu +1 位作者 Li Peng Lin-Bo Xie 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第1期591-596,共6页
This paper investigates asymptotic bounded consensus tracking(ABCT) of double-integrator multi-agent systems(MASs) with an asymptotically-unbounded-acceleration and bounded-jerk target(AUABJT) available to parti... This paper investigates asymptotic bounded consensus tracking(ABCT) of double-integrator multi-agent systems(MASs) with an asymptotically-unbounded-acceleration and bounded-jerk target(AUABJT) available to partial agents based on sampled-data without velocity measurements. A sampled-data consensus tracking protocol(CTP) without velocity measurements is proposed to guarantee that double-integrator MASs track an AUABJT available to only partial agents.The eigenvalue analysis method together with the augmented matrix method is used to obtain the necessary and sufficient conditions for ABCT. A numerical example is provided to illustrate the effectiveness of theoretical results. 展开更多
关键词 asymptotic bounded consensus tracking multi-agent systems without velocity measurements sampled-data control
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Comparative Analysis on Two Kinds of Measurement Methods of Particulate Matters in Waste Gas of Low Velocity
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作者 Li Weijun Ji Guangjun +2 位作者 Yang Xianglin Zhang Xingyao Jing Yifeng 《Meteorological and Environmental Research》 CAS 2019年第5期70-73,共4页
In the current waste gas sampling of fixed source,it is required that deviation of tracking rate of constant velocity sampling should not be more than 10%.When flow rate of the waste gas is less than 5 m/s,the trackin... In the current waste gas sampling of fixed source,it is required that deviation of tracking rate of constant velocity sampling should not be more than 10%.When flow rate of the waste gas is less than 5 m/s,the tracking rate can not meet this requirement.The sampling of fixed velocity can meet the requirement of particulate matter sampling on gas collection volume at low velocity.Through the comparison of two different methods for the determination of particulate matter in waste gas under the low flow velocity of flue gas,it was found that there were some differences between the fixed velocity measurement and the constant velocity measurement.The results showed that measurement result of the fixed velocity was higher than that of constant velocity measurement under low velocity.At the same time,the deviation of fixed velocity measurement was not obvious under different low velocity. 展开更多
关键词 LOW flow velocity PARTICULATE MATTER measurement COMPARATIVE analysis
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