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Source-Space Compressive Matched Field Processing for Source Localization
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作者 王好忠 王宁 +1 位作者 高大治 高博 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第4期60-63,共4页
Source localization by matched-field processing (MFP) can be accelerated by building a database of Green's functions which however requires a bulk-storage memory. According to the sparsity of the source locations i... Source localization by matched-field processing (MFP) can be accelerated by building a database of Green's functions which however requires a bulk-storage memory. According to the sparsity of the source locations in the search grids of MFP, compressed sensing inspires an approach to reduce the database by introducing a sensing matrix to compress the database. Compressed sensing is further used to estimate the source locations with higher resolution by solving the β -norm optimization problem of the compressed Green's function and the data received by a vertieal/horizontal line array. The method is validated by simulation and is verified with the experimental data. 展开更多
关键词 of SSC MFP in Source-Space compressive Matched Field processing for Source Localization for that IS
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Effect of Deformation Condition on Axial Compressive Precision Forming Process of Tube with Curling Die
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作者 He YANG and Zhichao SUN College of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072, China 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2001年第1期135-136,共2页
The effect of the deformation condition on the axial compressive precision forming process of tube with curling die was investigated by using a rigid-plastic FEM. The results show that the forming accuracy depends mai... The effect of the deformation condition on the axial compressive precision forming process of tube with curling die was investigated by using a rigid-plastic FEM. The results show that the forming accuracy depends mainly on geometric condition rp/d0, little on tube material properties and friction condition; the relative gap △/2rp of double-walled tubes obtained decreases with Increasing rp/d0, and there is a parameter k for a given to/do or rp/t0, when rp/d0 >k, △/2rp< 1, otherwise △/2rp>1. 展开更多
关键词 Effect of Deformation Condition on Axial compressive Precision Forming process of Tube with Curling Die
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High temperature deformation behavior and optimization of hot compression process parameters in TC11 titanium alloy with coarse lamellar original microstructure 被引量:4
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作者 鲁世强 李鑫 +2 位作者 王克鲁 董显娟 傅铭旺 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第2期353-360,共8页
The high temperature deformation behaviors of α+β type titanium alloy TC11 (Ti-6.5Al-3.5Mo-1.5Zr-0.3Si) with coarse lamellar starting microstructure were investigated based on the hot compression tests in the tem... The high temperature deformation behaviors of α+β type titanium alloy TC11 (Ti-6.5Al-3.5Mo-1.5Zr-0.3Si) with coarse lamellar starting microstructure were investigated based on the hot compression tests in the temperature range of 950-1100 ℃ and the strain rate range of 0.001-10 s-1. The processing maps at different strains were then constructed based on the dynamic materials model, and the hot compression process parameters and deformation mechanism were optimized and analyzed, respectively. The results show that the processing maps exhibit two domains with a high efficiency of power dissipation and a flow instability domain with a less efficiency of power dissipation. The types of domains were characterized by convergence and divergence of the efficiency of power dissipation, respectively. The convergent domain in a+fl phase field is at the temperature of 950-990 ℃ and the strain rate of 0.001-0.01 s^-1, which correspond to a better hot compression process window of α+β phase field. The peak of efficiency of power dissipation in α+β phase field is at 950 ℃ and 0.001 s 1, which correspond to the best hot compression process parameters of α+β phase field. The convergent domain in β phase field is at the temperature of 1020-1080 ℃ and the strain rate of 0.001-0.1 s^-l, which correspond to a better hot compression process window of β phase field. The peak of efficiency of power dissipation in ℃ phase field occurs at 1050 ℃ over the strain rates from 0.001 s^-1 to 0.01 s^-1, which correspond to the best hot compression process parameters of ,8 phase field. The divergence domain occurs at the strain rates above 0.5 s^-1 and in all the tested temperature range, which correspond to flow instability that is manifested as flow localization and indicated by the flow softening phenomenon in stress-- strain curves. The deformation mechanisms of the optimized hot compression process windows in a+β and β phase fields are identified to be spheroidizing and dynamic recrystallizing controlled by self-diffusion mechanism, respectively. The microstructure observation of the deformed specimens in different domains matches very well with the optimized results. 展开更多
关键词 titanium alloy coarse lamellar microstructure high temperature deformation behavior processing map hot compression process parameter optimization
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On a general theory for compressing process and aeroacoustics:linear analysis 被引量:4
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作者 E .Mao Y. P. Shi J. Z. Wu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2010年第3期355-364,共10页
Of the three mutually coupled fundamental processes (shearing, compressing, and thermal) in a general fluid motion, only the general formulation for the compress- ing process and a subprocess of it, the subject of a... Of the three mutually coupled fundamental processes (shearing, compressing, and thermal) in a general fluid motion, only the general formulation for the compress- ing process and a subprocess of it, the subject of aeroacous- tics, as well as their physical coupling with shearing and thermal processes, have so far not reached a consensus. This situation has caused difficulties for various in-depth complex multiprocess flow diagnosis, optimal configuration design, and flow/noise control. As the first step toward the desired formulation in fully nonlinear regime, this paper employs the operator factorization method to revisit the analytic linear theories of the fundamental processes and their decomposi- tion, especially the further splitting of compressing process into acoustic and entropy modes, developed in 1940s-1980s. The flow treated here is small disturbances of a compressible, viscous, and heat-conducting polytropic gas in an unbounded domain with arbitrary source of mass, external body force, and heat addition. Previous results are thereby revised and extended to a complete and unified theory. The theory pro- vides a necessary basis and valuable guidance for developing corresponding nonlinear theory by clarifying certain basic issues, such as the proper choice of characteristic variables of compressing process and the feature of their governing equations. 展开更多
关键词 Longitudinal (compressing) processTransversal (shearing) process Acoustic mode Entropy mode Aeroacoustics
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PHSICAL MODELLING AND PROCESSING OF Ti-6Al-4V ELI 被引量:2
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作者 C.P. Chou, S.C. Wang, C.C. Chang and W.R. Wang 1) Department of Mechanical Engineering, National Chiao Tung University Hsinchu, Taiwan 300, China 2) Materials Research Laboratories, Industrial Technology Research Institute Chutung, Taiwan 310, China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2000年第2期606-610,共5页
Titanium has been widely used as the implant materials of joint prostheses. This paper simulates the microstructures of the hot forged titanium knee joint component by physical modeling. Ti-6Al-4V ELI were deformed b... Titanium has been widely used as the implant materials of joint prostheses. This paper simulates the microstructures of the hot forged titanium knee joint component by physical modeling. Ti-6Al-4V ELI were deformed by GLEEBLE 2000 hot deforma- tion simulator in compression mode to determine the hot workability, in the range of 900 to 1100℃, with the strain rates between 0.05 to 5 s^(-1). Test results derived from specimens processed by on-cooling test and on-heating test were compared, thereby estimating the effect due to thermal history. The forging process of Ti-6Al-4V ELI tibial base plate of knee joint prostheses was design based on the workability data obtained. 展开更多
关键词 physical modeling hot workability processing map compression test hot forging
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Experimental investigation on the energy evolution of dry and water-saturated red sandstones 被引量:26
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作者 Zhang Zhizhen Gao Feng 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2015年第3期383-388,共6页
In order to investigate the effect of water content on the energy evolution of red sandstone, the axial loading–unloading experiments on dry and water-saturated sandstone samples were conducted, and the distribution ... In order to investigate the effect of water content on the energy evolution of red sandstone, the axial loading–unloading experiments on dry and water-saturated sandstone samples were conducted, and the distribution and evolution of elastic energy and dissipated energy within the rock were measured.The results show that the saturation process from dry to fully-saturated states reduces the strength, rigidity and brittleness of the rock by 30.2%, 25.5% and 16.7%, respectively. The water-saturated sample has larger irreversible deformation in the pre-peak stage and smaller stress drop in the post-peak stage.The saturation process decreases the accumulation energy limit by 38.9%, but increases the dissipated energy and residual elastic energy density, thus greatly reducing the magnitude and rate of energy release. The water-saturated sample has lower conversion efficiency to elastic energy by 3% in the prepeak region; moreover, the elastic energy ratio falls with a smaller range in the post-peak stage.Therefore, saturation process can greatly reduce the risk of dynamic disaster, and heterogeneous water content can lead to dynamic disaster possibly on the other hand. 展开更多
关键词 Rock mechanics Energy evolution Energy distribution Triaxial compression Saturation process
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Flow stress behavior of high-purity Al-Cu-Mg alloy and microstructure evolution 被引量:3
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作者 李立 李慧中 +2 位作者 梁霄鹏 黄岚 洪涛 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第3期815-820,共6页
The flow stress behavior of high-purity Al-Cu-Mg alloy under hot deformation conditions was studied by Gleeble-1500,with the deformation temperature range from 300 to 500 °C and the strain rate range from 0.01 to... The flow stress behavior of high-purity Al-Cu-Mg alloy under hot deformation conditions was studied by Gleeble-1500,with the deformation temperature range from 300 to 500 °C and the strain rate range from 0.01 to 10 s-1. From the true stress-true strain curve, the flow stress increases with the increasing of strain and tends to be constant after a peak value, showing dynamic recover, and the peak value of flow stress increases with the decreasing of deformation temperature and the increasing of strain rate.When the strain rate is 10 s-1 and the deformation temperature is higher than 400 °C, the flow stress shows dynamic recrystallization characteristic. TEM micrographs were used to reveal the evolution of microstructures. According to the processing map at true strain of 0.7, the feasible deformation conditions are high strain rate(>0.5 s-1) or 440-500 °C and 0.01-0.02 s-1. 展开更多
关键词 high-purity Al-Cu-Mg alloy hot compression flow stress processing map
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Valorization of mining waste and tailings through paste backfilling solution, Imiter operation, Morocco 被引量:8
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作者 Khaldoun Abdelhadi Ouadif Latifa +1 位作者 Baba Khadija Bahi Lahcen 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2016年第3期511-516,共6页
Mine waste and process tailings storage is one of important challenge for which mining operations are increasingly confronted. Treatment discharges of plants and main part of waste rock development are generally store... Mine waste and process tailings storage is one of important challenge for which mining operations are increasingly confronted. Treatment discharges of plants and main part of waste rock development are generally stored on surface areas. The volume and chemical characteristics of these materials generate serious problem for required storage spaces and mainly environmental degradation. Paste backfill(PBF) is one of ingenious solutions to minimize the quantity of tailings to store. PBF is basically defined as a combination of mine processing tailings, binder, and water mixing. The purpose of this paper is to present backfilling components characterization and formula verification for a waste valorization solution through paste backfilling technology in Imiter operation. Obtained results and realized analysis demonstrate PBF conformity and adequacy with assigned underground functions. However the studied recipe can be more ameliorated to obtain an optimal mixture ensuring the required mechanical strength. 展开更多
关键词 Mining waste process tailings Valorization Paste backfill Uni-axial compressive strength
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On the governing equations for the compressing process and its coupling with other processes 被引量:3
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作者 MAO Feng SHI YiPeng +2 位作者 XUAN LiJun SU WeiDong WU JieZhi 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2011年第6期1154-1167,共14页
As a continuation of a recent linear analysis by Mao et al.(Acta Mech Sin,2010,26:355),in this paper we propose a general theoretical formulation for the compressing process in complex Newtonian fluid flows,which cove... As a continuation of a recent linear analysis by Mao et al.(Acta Mech Sin,2010,26:355),in this paper we propose a general theoretical formulation for the compressing process in complex Newtonian fluid flows,which covers gas dynamics,aeroacoustics,nonlinear thermoviscous acoustics,viscous shock layer,etc.,as its special branches.The principle on which our formulation is based is the maximally natural and dynamic Helmholtz decomposition of the Navier-Stokes equation,along with the kinematic Helmholtz decomposition of the velocity field.The central results are the new dilatation equation and velocity-potential equation,which are the counterparts of vorticity transport equation and vector stream-function equation for the shearing process,respectively.Various couplings of the compressing process with shearing and thermal processes,including its physical sources,are carefully identified.While the possible applications and influences of the new formulation are yet to be explored,our preliminary discussion on the pros and cons of previous formulations pertain to acoustic analogy and that on the process splitting and coupling in highly compressible turbulence indicates that at least the formulation can serve as a new frame of reference by which one may gain some additional insight and thereby develop new approaches to the multi-process complex flow problems. 展开更多
关键词 longitudinal (compressing) process transversal (shearing) process Helmholtz decomposition aeroacoustics compressible turbulence
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A Reducing Iteration Orthogonal Matching Pursuit Algorithm for Compressive Sensing 被引量:18
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作者 Rui Wang Jinglei Zhang +1 位作者 Suli Ren Qingjuan Li 《Tsinghua Science and Technology》 SCIE EI CAS CSCD 2016年第1期71-79,共9页
In recent years, Compressed Sensing(CS) has been a hot research topic. It has a wide range of applications, such as image processing and speech signal processing owing to its characteristic of removing redundant inf... In recent years, Compressed Sensing(CS) has been a hot research topic. It has a wide range of applications, such as image processing and speech signal processing owing to its characteristic of removing redundant information by reducing the sampling rate. The disadvantage of CS is that the number of iterations in a greedy algorithm such as Orthogonal Matching Pursuit(OMP) is fixed, thus limiting reconstruction precision.Therefore, in this study, we present a novel Reducing Iteration Orthogonal Matching Pursuit(RIOMP) algorithm that calculates the correlation of the residual value and measurement matrix to reduce the number of iterations.The conditions for successful signal reconstruction are derived on the basis of detailed mathematical analyses.When compared with the OMP algorithm, the RIOMP algorithm has a smaller reconstruction error. Moreover, the proposed algorithm can accurately reconstruct signals in a shorter running time. 展开更多
关键词 compressed sensing signal processing wireless sensor networks
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Reconfigurable single-shot incoherent optical signal processing system for chirped microwave signal compression 被引量:3
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作者 Ming Li Shuqian Sun +4 位作者 Antonio Malacarne Sophie LaRochelle Jianping Yao Ninghua Zhu Jose Azana 《Science Bulletin》 SCIE EI CAS CSCD 2017年第4期242-248,共7页
We propose and demonstrate a reconfigurable and single-shot incoherent optical signal processing system for chirped microwave signal compression, using a programmable optical filter and a multiwavelength laser(MWL). T... We propose and demonstrate a reconfigurable and single-shot incoherent optical signal processing system for chirped microwave signal compression, using a programmable optical filter and a multiwavelength laser(MWL). The system is implemented by temporally modulating a specially shaped MWL followed by a suitable linear dispersive medium. A microwave dispersion value up to 1.33 ns/GHz over several GHz bandwidth is achieved based on this approach. Here we demonstrate a singleshot compression for different linearly chirped microwave signals over several GHz bandwidth. In addition, the robustness of the proposed system when input RF signals are largely distorted is also discussed. 展开更多
关键词 Fourier optics and signal processingAnalog optical signal processing Radio frequency photonics Pulse compression
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High temperature deformation behavior and processing map of hot isostatically pressed Ti-47.5Al-2Cr-2Nb-0.2W-0.2B alloy using gas atomization powders 被引量:2
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作者 Ying Bao Dong-ye Yang +4 位作者 Na Liu Guo-qing Zhang Zhou Li Fu-yang Cao Jian-fei Sun 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2017年第4期435-441,共7页
The hot compressive deformation behavior of hot isostatically pressed Ti-47.5Al-2Cr-2Nb-0.2W-0.2B alloy using gas atomization powders was systematically investigated and the processing map was obtained in the temperat... The hot compressive deformation behavior of hot isostatically pressed Ti-47.5Al-2Cr-2Nb-0.2W-0.2B alloy using gas atomization powders was systematically investigated and the processing map was obtained in the temperature range of 1323-1473 Kand strain rate range of 0.001-0.5s^(-1).The calculated activation energy in the above variational ranges of temperature and strain rate possesses a low activation energy value of approximately 365.6kJ/mol based on the constitutive relationship models developed with the Arrhenius-type constitutive model respectively considering the strain rate and deformation temperature.The hot working flow behavior during the deformation process was analyzed combined with the microstructural evolution.Meanwhile,the processing maps during the deformation process were established based on the dynamic material model and Prasad instability criterion under different deformation conditions.Finally,the optimal hot processing window of this alloy corresponding to the wide temperature range of 1353-1453 Kand the low strain rate of 0.001-0.1s^(-1) was obtained. 展开更多
关键词 Hot compressive deformation TiAl alloy Constitutive equation processing map Gas atomization Hot isostatic pressing
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Dynamic Fractal Transform with Applications to Image Data Compression
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作者 王舟 余英林 《Journal of Computer Science & Technology》 SCIE EI CSCD 1997年第3期202-209,共8页
A recent trend in computer graphics and image processing is to use Iterated Function System (IFS) to generate and describe both man-made graphics and natural images. Jacquin was the first to propose a fully automatic ... A recent trend in computer graphics and image processing is to use Iterated Function System (IFS) to generate and describe both man-made graphics and natural images. Jacquin was the first to propose a fully automatic gray scale image compression algorithm which is referred to as a typical static fractal transform based algorithm in this paper. By using this algorithm, an image can be condensely described as a fractal transform operator which is the combination of a set of fractal mappings. When the fractal transform operator is iteratedly applied to any initial image, a unique attractor (reconstructed image) can be achieved. In this paper) a dynamic fractal transform is presented which is a modification of the static transform. Instead of being fixed, the dynamic transform operator varies in each decoder iteration, thus differs from static transform operators. The new transform has advantages in improving coding efficiency and shows better convergence for the decoder. 展开更多
关键词 Fractals Iterated Function System (IFS) data compression image processing
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