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STRUCTURE EVOLUTION OF POLYMER CHAINS FOR NECKING FORMATION IN HIGH-SPEED FIBER SPINNING PROCESS

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Chinese Journal of Polymer Science 2006年第1期24卷 1-11页

作者： Hong Zheng Wei Yu Hong-bin Zhang and Chi-xing Zhou department of Polymer Materials Science & engineering,{2. Jiao Tong university,{2. 2.02.0,china shanghai Jiao Tong Univ Dept Polymer Mat Sci & Engn Shanghai 200240 Peoples R China

Finite element method is used to simulate the high-speed melt spinning process, based on the equation system proposed by Doufas et al. Calculation predicts a neck-like deformation, as well as the related profiles of velocity, diameter, temperature, chain orientation, and crystallinity in the fiber spinning process. Considering combined effects on the process such as flow-induced crystallization, viscoelasticity, filament cooling, air drag, inertia, surface tension and gravity, the simulated material flow behaviors are consistent with those observed for semi-crystalline polymers under various spinning conditions, The structure change of polymer coils in the necking region described by the evolution of conformation tensor is also investigated. Based on the relaxation mechanism of macromolecules in flow field different types of morphology change of polymer chains before and in the neck are proposed, giving a complete prospect of structure evolution and crystallization of semi-crystalline polymer in the high speed fiber spinning process.

关键词： Semi-crystalline Polymer Crystallization High-speed Fiber Spinning Process Conformation Finite Element Method (FEM).

A simple solution route to control synthesis of Fe_3O_4 nanomaterials at low temperature and their magnetic properties

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Science china Chemistry 2009年第7期52卷 916-923页

作者： LIU Yi1,2. CHEN Yun1, ZENG YuPing2.& WANG ShiLong3 1 department of Chemistry and Chemical engineering, Zaozhuang {2., Zaozhuang 2.7160, china 2.shanghai Institute of Ceramics, Chinese Academy of Sciences, shanghai 2.0050, china 3 School of Life Science and Technology, Tongji {2., shanghai 2.0092. china 1. department of Chemistry and Chemical engineering Zaozhuang University Zaozhuang 277160 China 2. shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China 3. School of Life Science and Technology Tongji University Shanghai 200092 China

A series of nanostructured iron compounds including cubic Fe3O4 and orthorhombic FeOOH were synthesized via a facile low temperature (in the range of 60-100℃) solution method. In the whole process, the interaction between FeCl2.4H2. and methenamine (C6H12.4) was carried out through a reflux device under different reaction conditions such as temperature, solvent, and duration. The samples were detected by XRD, TEM, SAED, physical property measurement system, and Mssbauer spectroscopy, separately. The experiments showed that magnetic mixture nanoparticles had flake and rod morphologies, and cubic Fe3O4 took on grain nanostructure. Magnetism measurements indicated that the saturated magnetization of the as-obtained magnetic mixture was lower than that of the cubic magnetite. Mssbauer spectroscopy testified the sample consisting of cubic magnetite rather than γ-Fe2.3. In addition, a possible growth mechanism of cubic magnetic nanoparticles under different conditions was discussed.

关键词： magnetic nanoparticles cubic Fe3O4 oxidation-coprecipitation method reflux magnetic properties at room temperature Mssbauer spectrum

Preparation and Microstructure of Spinel Zinc Ferrite ZnFe_2._4 by Co-precipitation Method

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Journal of Wuhan university of Technology(Materials Science) 2009年第6期24卷 927-930页

作者：任平 department of Energy Sources and Environment engineering Shanghai University of Electric Power

Spinel zinc ferrites ZnFe2.4, prepared by co-precipitation method using the zinc nitrate Zn（NO3）2.6H2. and ferric nitrate Fe（NO3）3·2.2. as the raw materials, were characterized by the thermo gravimetric analysis （TG） and differential scanning calorimeter （DSC）, X-ray diffraction （XRD） and scanning electron microscope （SEM）. The influence of synthesis conditions, such as Zn/Fe molar ratio, pH value, the sintering temperature and time, on the microstructures was detailedly investigated. The relationships between the microstructures and the synthesis conditions were discussed. The results show that the pure spinel zinc ferrites ZnFe2.4 are formed when the Zn/Fe molar ratio is 1.05∶2.at pH=8.5 or Zn/Fe molar ratio is 1∶2.at Ph=9-10, and the precursors are sintered at 1100 ℃ for 4 h. Especially no other phases are observed when the Zn/Fe molar ratio is 1∶2.at pH=10 and the precursor is sintered above 700 ℃ for 4 h. The higher sintering temperature and longer sintering time contribute to grain growth.

关键词： zinc ferrites ZnFe2.4 microstructures co-precipitation

Data fusion for target tracking in wireless sensor networks using quantized innovations and Kalman filtering

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Science china(Information Sciences) 2012年第3期55卷 530-544页

作者： XU Jian1,2., LI JianXun1,2.& XU Sheng3 1department of Automation, Science and Technology on Avionics Integration Laboratory, shanghai Jiao Tong {2., shanghai 2.02.0, china 2.0} of Automation, System Control and Information Processing, Ministry of Education of china, shanghai Jiao Tong {2., shanghai 2.02.0, china 3School of Mechanical engineering, shanghai Jiao Tong {2., shanghai 2.02.0, china 1. department of Automation Science and Technology on Avionics Integration Laboratory Shanghai Jiao Tong University Shanghai 200240 China2. Department of Automation System Control and Information Processing Ministry of Education of China Shanghai Jiao Tong University Shanghai 200240 China3. School of Mechanical Engineering Shanghai Jiao Tong University Shanghai 200240 China

A novel networked data-fusion method is developed for the target tracking in wireless sensor networks (WSNs). Specifically, this paper investigates data fusion scheme under the communication constraint between the fusion center and each sensor. Such a message constraint is motivated by the bandwidth limitation of the communication links, fusion center, and by the limited power budget of local sensors. In the proposed scheme, each sensor collects one noise-corrupted sample, performs a quantizing operation, and transmits quantized message to the fusion center. Then the fusion center combines the received quantized messages to produce a final estimate. The novel data-fusion method is based on the quantized measurement innovations and decentralized Kalman filtering (DKF) with feedback. For the proposed algorithm, the performance analysis of the estimation precision is provided. Finally, Monte Carlo simulations show the effectiveness of the proposed scheme.

关键词： data fusion target tracking limited bandwidth quantized innovation Kalman filtering

Preliminary design and parametric study of 1400 m partially earth-anchored cable-stayed bridge

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Science china(Technological Sciences) 2010年第2期53卷 502-511页

作者： SUN Bin, CHENG Jin & XIAO RuCheng department of Bridge engineering, Tongji {2., shanghai 2.0092. china 1. department of Bridge engineering Tongji University Shanghai 200092 China

The preliminary design and parametric study of 1400 m partially earth-anchored cable-stayed bridge are described. Static per-formance of this new type of bridge is discussed. Compared with fully self-anchored cable-stayed bridge, its advantages in fin-ished state are summarized. Based on numerical calculation, effects of several structural parameters on static performance are presented.

关键词： partially earth-anchored cable-stayed bridge preliminary design parametric study

FLOW AROUND A CIRCULAR CYLINDER USING A FINITE-VOLUME TVD SCHEME BASED ON A VECTOR TRANSFORMATION APPROACH

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Journal of Hydrodynamics 2010年第2期22卷 221-228页

作者： WANG Jia-song School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai 200240China

Flows around a circular cylinder displaying an unsteady vortex shedding process at the Reynolds numbers of 1000,3900 and 1×104 are studied using a finite-volume Total Variation Diminishing（TVD） scheme for solving the Unsteady Reynolds-Averaged Navier-Stokes（URANS） *** Elemental Velocity Vector Transformation（EVVT） approach is proposed for the local normal and tangential velocity transformation at the interfaces of main and satellite *** presented method is validated by comparing with the available experimental data and numerical *** is shown that the two-dimensional TVD finite volume method with the Renormalization Group（RNG） turbulence model can be used to determine hydrodynamic forces and captures vortex shedding characteristics very well.

关键词： Total Variation Diminishing(TVD) finite volume method Renormalization Group(RNG) turbulence model flow around circular cylinder Elemental Velocity Vector Transformation(EVVT)

INTERFERENCE OF SIDE STRUT WITH THE NATURAL CAVITATING FLOWS AROUND A SUBMERGED VEHICLE IN WATER TUNNEL EXPERIMENTS

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Journal of Hydrodynamics 2011年第5期23卷 554-561页

作者： CHEN Xin YAO Yan. LU Chuan-jing CHEN Ying CAOJia-yi department of engineering Mechanics Shanghai Jiao Tong University Shanghai 200240 China department of engineering Mechanics and State Key Laboratory of Ocean engineering Shanghai Jiao TongUniversity Shanghai 200240 China department of engineering Mechanics Shanghai Jiao Tong University Shanghai 200240 China

To apply the measurements of model experiment in water tunnel to the actual sailing condition, it is necessary to know accurately the strut effect and its rule. In the present work, the corresponding interferences of one-side strut and two-side strut on the natural cavitating flows around a submerged vehicle in water tunnel were investigated numerically, using the homogeneous equilibrium two-phase model coupled with a natural cavitation model. The numerical simulation results show that the strut types have distinct effects on the hydrodynamic properties. For the same given upstream velocity and downstream pressure, the existence of the strut leads to an increment of natural cavitation number, reduces the low-pressure region and depresses the pressure on the vehicle surface near the sides of strut. In the case of given cavitaiton number, the influences of the two-side strut on the drag and lift coefficients are both enhanced along with the increment of attack angle, however the influence of the one-side strut gradually gets stronger on the drag coefficient but weaker on the lift coefficient contrarily. In addition, based on the present numerical results, a correction method by introducing the sigmoidal logistic function is proposed to eliminate the interference from the foil-shaped strut.

关键词： strut effect natural cavitating flow submerged vehicle water tunnel experiment

Relations Between Characteristic Function,Positive P-Representation and Coherent Thermal State

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Communications in Theoretical Physics 2007年第7期48卷 67-70页

作者： FAN Hong-Yi XU Xing-Lei department of Material Science and engineering,{2. of Science and Technology of china,Hefei 2.002.,china2.department of Physics,shanghai Jiao Tong {2.,shanghai 2.0030,china3 department of Physics,Heze {2.,Heze 2.4015,china department of Material Science and engineering University of Science and Technology of China department of Physics Shanghai Jiao Tong University department of Physics Heze University

We employ the coherent thermal states(a kind of entangled states)in thermal field dynamics to establisha complete entangled state formalism expressing pseudo-classical representations of density operator for light ***,the relationship between the coherent thermal state and the characteristic function and the positive Prepresentation in quantum optics theory are obtained.

关键词： coherent thermal state characteristic function positive P-representation

Seamlet carving for shape-aware image resizing

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Science china(Information Sciences) 2012年第5期55卷 1073-1081页

作者： LIN Xiao 1,2.SHENG Bin 1,MA LiZhuang 1,SHEN Yang 1 & CHEN ZhiHua 3 1 department of Computer Science and engineering,{2. Jiao Tong university,{2. 2.02.0,china 2.Academy of Information Technology,Luoyang Normal university,Luoyang 47102.,china 3 department of Computer Science and engineering,East china university of Science and Technology,{2. 2.02.7,china 1. department of Computer Science and engineering Shanghai Jiao Tong University Shanghai 200240 China2. Academy of Information Technology Luoyang Normal University Luoyang 471022 China3. Department of Computer Science and Engineering East China University of Science and Technology Shanghai 200237 China

In this paper we propose an optimized seam-carving approach for anti-shearing image *** image/video seam-carving strategy only focuses on deleting the pixels along 8-connected seams,which may lead to the obvious information loss during *** the traditional seam-carving methods,our approach can construct a seamlet to handle the discontinuous pixels and further achieve an optimized image resizing results with *** particular,to suppress zigzag artifacts,we introduce the anti-shearing energy into the seamlet generation,which includes two steps:1) the energy map is formalized by using Gabor filtering and the saliency map;2. The energy computation is optimized in Gabor feature space to obtain the resizing results without the connectivity *** experimental results and comparisons show the effectiveness of our method.

关键词： image resizing seamlet carving saliency map