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Flexible Time Domain Averaging Technique

Chinese Journal of Mechanical Engineering 2013年第5期26卷 1022-1030页

作者： zhao ming LIN Jing LEI Yaguo wang Xiufeng School of Mechanical Engineering Xi’an Jiaotong University State Key Laboratory for Manufacturing Systems Engineering Xi’an Jiaotong University Shaanxi Key Laboratory of Product Quality Assurance & Diagnosis

Time domain averaging(TDA) is essentially a comb filter,it cannot extract the specified harmonics which may be caused by some faults,such as gear ***,TDA always suffers from period cutting error(PCE) to different *** improved TDA methods have been proposed,however they cannot completely eliminate the waveform reconstruction error caused by *** order to overcome the shortcomings of conventional methods,a flexible time domain averaging(FTDA) technique is established,which adapts to the analyzed signal through adjusting each harmonic of the comb *** this technique,the explicit form of FTDA is first constructed by frequency domain ***,chirp Z-transform(CZT) is employed in the algorithm of FTDA,which can improve the calculating efficiency *** the signal is reconstructed in the continuous time domain,there is no PCE in the *** validate the effectiveness of FTDA in the signal de-noising,interpolation and harmonic reconstruction,a simulated multi-components periodic signal that corrupted by noise is processed by *** simulation results show that the FTDA is capable of recovering the periodic components from the background noise ***,it can improve the signal-to-noise ratio by 7.9 dB compared with conventional *** are also carried out on gearbox test rigs with chipped tooth and eccentricity gear,*** is shown that the FTDA can identify the direction and severity of the eccentricity gear,and further enhances the amplitudes of impulses by 35%.The proposed technique not only solves the problem of PCE,but also provides a useful tool for the fault symptom extraction of rotating machinery.

关键词： time domain averaging chirp Z-transform period cutting error de-noising interpolation

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Disturbance of light-absorbing aerosols on the albedo in a winter snowpack of Central Tibet

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Journal of Environmental Sciences 2013年第8期25卷 1601-1607页

作者： Jing ming Pengling wang Shuyu zhao Pengfei Chen National Climate Center China Meteorological Administration State Key Laboratory of Cryospheric Sciences Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Institute of Tibetan Plateau Research Chinese Academy of Sciences

A field observation on the albedo of the snowpack in Central Tibet was conducted in the Nam Co region in the winter of 2011. Snow properties, including grain size and density, were measured in the field, and surface-layer snow samples （down to 5 cm） were collected. The average concentrations of black carbon and dust were 72 ppbm （close to that in the glaciers of Mt. Nyainqentanglha） and 120 ppmm, respectively. Inverse trends were found to exist between the albedo of the snowpack and light-absorbing aerosols （LAAs） as well as grain size growth. Modeling showed that black carbon, dust, and grain growth in the winter snowpack can reduce the broadband albedo by 11%, 28%, and 61%, respectively.

关键词： albedo black carbon dust snow Tibetan Plateau

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Numerical simulation of flow focusing pattern and morphological changes in two-phase flow inside nozzle

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Chinese Journal of Chemical Engineering 2019年第1期27卷 63-71页

作者： Jin zhao Zhi Ning ming Lü Geng wang College of Mechanical and Electrical Engineering Beijing Jiaotong University

The flow focusing nozzle is a new type of nozzle that performs effective atomization of the discrete phase by means of high-speed motion of the continuous *** flow pattern and its morphological changes have a significant effect on the atomization, but the influence of different parameters on the morphological change of the flow pattern remains *** flow focusing pattern and morphological changes in the two-phase flow inside the nozzle were simulated numerically, based on the volume of fluid *** results demonstrate that the ratio of the nozzle-to-capillary distance and capillary diameter, the gas–liquid velocity ratio, and capillary diameter have significant effects on the flow *** the ratio of the nozzle-to-capillary distance H and capillary diameter D increases, or the capillary diameter D increases, the flow pattern tends to transform into a laminar form; however, when the gas–liquid velocity ratio V increases, the flow pattern tends to transform into a turbulence ***, we define the cone-shaped expansion rate, cone-shaped focusing rate,and cone angle in order to study the morphological changes in the cone shape inside the *** results indicate that the morphological change of the cone shape and flow pattern transformation is *** the cone shape tends to be unstable, the flow pattern changes towards flow blurring, whereas, a stable cone indicates that the flow tends to exhibit a droplet pattern.

关键词： Flow focusing Pattern transformation Morphological changes Numerical simulation

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Effect of heat treatment on the microstructure and mechanical properties of structural steel–mild steel composite plates fabricated by explosion welding

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International Journal of Minerals,Metallurgy and Materials 2020年第8期27卷 1115-1122页

作者： En-ming Zhang Yi-ming zhao Zhong-mou wang Wen-ya Li State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of Friction Welding TechnologiesSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi'an710072China

Two dissimilar steel plates,structural steel and mild steel,were joined by explosion welding to form a *** composite was then heat-treated by quenching at 840℃ for 30 min followed by tempering at 200℃ for 3 *** microstructure was investigated under an optical microscope and a scanning electron *** mechanical properties were measured using Vickers microhardness and Charpy impact *** results show a deformed interface with typical wave features at the welding zone,but no defects were ***,the ferrite in the parent plate in the weld zone was elongated due to the strong plastic deformation from the *** heat treatment,the hardness of the flyer plate(structural steel)was over HV0.2800,while that of the parent plate(mild steel)was *** increase in hardness was due to the presence of ***,the average impact energy was increased from 18.5 to 44.0 J following heat treatment;this is because of the formation of recrystallized grains at the weld interface,which is due to the dynamic recovery and local recrystallization,and the strong elemental diffusion that occurred between the two plates.

关键词： explosion welding steel composite plate microstructure mechanical properties

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Effect of Ce on the cleanliness, microstructure and mechanical properties of high strength low alloy steel Q690E in industrial production process

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International Journal of Minerals,Metallurgy and Materials 2019年第11期26卷 1372-1384页

作者： Hao wang Yan-ping Bao ming zhao Min wang Xiao-ming Yuan Shuai Gao State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Technical Center of Inner Mongolia Baotou Steel Union Co. Ltd.Baotou 014010China The Rare Earth Steel Plates Plant of Baotou Iron and Steel Co. Ltd.Baotou 014010China

In order to improve the strength and toughness of Q690 E steel sheets,the effect of rare earth element Ce on the strength and toughness of Q690 E steel was studied by means of transmission electron microscopy,scanning electron microscopy,and metallographic *** results showed that the addition of Ce in steel limited the combination of S with Mn and Ca,transformed Al2O3 inclusion into spherical CeAlO3 inclusion,and modified the precipitate form of some composite inclusions of TiN and sulfide oxides into TiN precipitation *** inclusions were *** size of inclusions was decreased from 3–5μm to 1–2μm,and the distribution was *** played a role in purifying molten steel through desulphurization and ***,the addition of Ce in steel effectively increased the nucleation particles in the liquid phase,improved the nucleation rate,enlarged the equiaxed grain refinement area,and limited the development of columnar *** average grain size of slab decreased from 45.76 to 35.25μm,and the proportion of large grain size(>50μm)decreased from 40.41%to 23.74%.The macrostructural examination of slab was improved from B0.5 to C2.0,which realized the refinement of the solidified structure and reduced the banded structure of hot rolled *** addition,due to the inheritance of refined structure in the upstream,the recrystallization of deformed austenite and the growth of grain after recrystallization were restrained,and a refined tempered sorbite structure was *** rare earth element Ce was added,the width of the martensite lath bundle was narrowed from about 500 nm to about 200 nm,which realized a remarkable grain refinement strengthening and toughening *** properties such as tensile,yield,and low-temperature impact toughness were significantly improved.

关键词： rare earth HSLA steel inclusion structure grain refinement strengthening

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Numerical simulation of 3D-microstructures in solidification processes based on the CAFE method

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International Journal of Minerals,Metallurgy and Materials 2009年第6期16卷 640-645页

作者： Jin-long wang Fu-ming wang Yan-yu zhao Jiong-ming Zhang Wei Ren School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China

It was analyzed that the finite element-cellular automaton （CAFE） method was used to simulate 3D-microstructures in solidification processes. Based on this method, the 3D-microstructure of 9SMn28 free-cutting steel was simulated in solidification processes and the simulation results are consistent with the experimental ones. In addition, the effects of Gaussian distribution parameters were also studied. The simulation results show that the higher the mean undercooling, the larger the columnar dendrite zones, and the larger the maximum nucleation density, the smaller the size of grains. The larger the standard deviation, the less the number of minimum grains is. However, the uniformity degree decreases first, and then increases gradually.

关键词： finite element-cellular automaton model numerical simulation solidification 3D-microstructure Gaussian distribution parameters

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Anisotropic superconducting properties of FeSe_(0.5)Te_(0.5) single crystals

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Chinese Physics B 2022年第9期31卷 519-526页

作者： Jia-ming zhao Zhi-He wang School of Physics Nanjing UniversityNanjing 210093China Center for Superconducting Physics and Materials Collaborative Innovation Center of Advanced Microstructures and National Laboratory of Solid State MicrostructuresNanjing UniversityNanjing 210093China

We investigated the anisotropic electrical transport and magnetic properties of FeSe_(0.5)Te_(0.5) single crystals grown by the self-flux *** in-plane resistivity shows a metallic-like temperature dependence,while the out-of-plane resistivity shows a broad hump with a maximum at around 64 *** magnetization loops for H//c-axis and H//ab-plane are also different,for example,there is a typical second peak for H//*** in-plane critical current density is larger than the out-of-plane *** coherence length and penetration depth were estimated by the Ginzburg-Landau *** anisotropic parameterγdepends on the applied magnetic field and the *** coupling of superconducting FeSe(Te)layers and the flux pinning mechanism relevant to anisotropy are also discussed.

关键词： FeSe_(1-x)Te_(r)single crystal anisotropy resistivity magnetization

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Experimental detection of quantum entanglement

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Frontiers of physics 2013年第4期8卷 357-374页

作者： ming Li ming-Jing zhao Shao-ming Fei Zhi-Xi wang College of the Science China University of Petroleum Qingdao 266580 China School of Mathematical Sciences Capital Normal University Beijing 100048 China Max-Planck-Institute for Mathematics in the Sciences Leipzig 04103 Germany

In this review, we introduce some methods for detecting or measuring entanglement. Several non- linear entanglement witnesses are presented. We derive a series of Bell inequalities whose maximally violations for any multipartite qubit states can be calculated by using our formulas. Both the non- linear entanglement witnesses and the Bell inequalities can be operated experimentally. Thus they supply an effective way for detecting entanglement. We also introduce some experimental methods to measure the entanglement of formation, and the lower bound of the convex-roof extension of negativity.

关键词： quantum entanglement Bell-type inequality entanglement detection

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Entanglement Transfer via Heisenberg Interaction in a Four-Qubit System

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Communications in Theoretical Physics 2007年第4期47卷 621-624页

作者： REN Feng-Hua wang zhao-ming School of Computer Engineering Qingdao Technological University Qingdao 266033 China Department of Physics Beijing Institute of Technology Beijing 100081 China

We investigate the entanglement transfer in a four-qubit system and calculate the concurrence between any two qubits in different initial states. We show that both the pure entangled state and mixed entangled state can be transferred. For some special coupling constants and some evolution time, entanglement can be completely transferred from one pair particles to another.

关键词： entanglement transfer Heisenberg interaction

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Direct estimation of the Solar acceleration using geodetic/astrometric VLBI observations

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Science China(Physics,Mechanics & Astronomy) 2012年第2期55卷 329-332页

作者： XU mingHui wang GuangLi zhao ming Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

The secular aberration drift observed as the apparent proper motion of extragalactic radio sources is caused by the acceleration of the coordinate origin,the Solar System ***,the acceleration can be estimated as a global parameter by using the 30 years global geodetic/astrometric VLBI *** estimation is independent of any kinematic or dynamic model of the Milky Way or statistics *** estimated acceleration in the direction of the Galactic center is (0.80±0.04) cm·s-1 ·yr-1,while the other two components are (0.0-1±0.06) and (0.52±0.05) cm ·s-1 ·yr-1 in the direction along the Solar motion in the Galactic plane and in the direction normal to the Galactic plane,*** estimate of the acceleration independently provides another kinematics parameter without referring to any objects within the Galaxy.

关键词： solar acceleration secular aberration VLBI astrometry

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