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MULTI-MODE OF VORTEX-INDUCED VIBRATION OF A FLEXIBLE CIRCULAR CYLINDER

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Journal of Hydrodynamics 2011年第4期23卷 483-490页

作者： XIE fang-fang DENG Jian zheng Yao School of Aeronautics and Astronautics Zhejiang University Hangzhou 310027 China

The vortex-induced vibration of a flexible circular cylinder is investigated at a constant Reynolds number of 1000. The finite-volume method on moving meshes is applied for the fluid flow, and the Euler-Bernoulli beam theory is used to model the dynamic response of a flexible cylinder. The relationship between the reduced velocity and the amplitude response agrees well with the experimental results. Moreover, five different vibrating modes appear in the simulation. From the comparisons of their vortex structures, the strength of the wake flow is related to the exciting vibrating mode and different vortex patterns arise for different vibrating modes. Only 2P pattern appears in the first vibrating mode while 2S-2P patterns occur in the other vibrating modes if monitoring at different sections along the length of the cylinder. The vibration of the flexible cylinder can also greatly alter the three-dimensionality in the wake, which needs further studies in our future work, especially in the transition region for the Reynolds number from 170 to 300.

关键词： multi-mode Vortex-Induced Vibration (VIV) three-dimensional instability flexible cylinders Euler-Bemoulli beam

Cognitive anti-jamming receiver under phase noise in high frequency bands

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Journal of Systems Engineering and Electronics 2018年第1期29卷 31-38页

作者： fang zheng LI Haitao QIAN Yiming School of Electronic Information and Electrical EngineeringShanghai Jiao Tong UniversityShanghai 200240China China Science and Technology on Avionics Integration Laboratory Shanghai 200233China Faculty of Information Technology Beijing University of TechnologyBeijing 100124China China Nuclear Control System Engineering CO. LTDBeijing 100176China

This paper investigates the jamming sensing performance of the simultaneous transmit and receive based cognitive anti-jamming(SCAJ) receiver impaired by phase noise in local oscillators(LO) over fading channels. Firstly, energy detection(ED)based on the jamming to noise ratio(JNR) of the high frequency bands SCAJ receiver with phase noise under different channels is analyzed. Then, the probabilities of jamming detection and false alarm in closed-form for the SCAJ receiver are derived. Finally,the modified Bayesian Cramer-Rao bound(BCRB) of jamming sensing for the SCAJ receiver is presented. Simulation results show that the performance degradation of the SCAJ system due to phase noise is more severe than that due to the channel fading in the circumstances where the signal bandwidth(BW) is kept a constant. Moreover, the signal BW has an effect on the phase noise in LO, and the jamming detection probability of the wideband SCAJ receiver with lower phase noise outperforms that of the narrowband receiver using the same center frequency. Furthermore,an accurate phase noise estimation and compensation scheme can improve the jamming detection capability of the SCAJ receiver in high frequency bands and approach to the upper bound.

关键词： high frequency band simultaneous transmit and receive phase noise cognitive anti-jamming

Temperature-responsive Behavior of Polymer Fluorescent System via Electrostatic Interaction Mediated Aggregation/Deaggregation

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Chinese Journal of Polymer Science 2016年第7期34卷 830-837页

作者： si-hua guo fang-yuan zheng fang zeng 吴水珠 College of Materials Science and Engineering State Key Laboratory of Luminescent Materials and Devices South China University of Technology Guangzhou 510640 China

A simple and effective polymer fluorescent thermosensitive system was successfully developed based on the synergistic effect of excimer/monomer interconversion of pyrene derivatives and electrostatic interaction between polyelectrolyte and charged fluorophore. As for the system, the excimer-monomer conversion, thermosensitive behavior and thermo-responsive reversibility were investigated experimentally. Temperature variation and temperature-distribution induced fluorescence changes can be observed directly by naked eyes. Thus, this polymer system holds promise for serving as a fluorescent thermometer.

关键词： Polymer fluorescent thermometer Temperature-responsive Electrostatic interaction Aggregation Deaggregation

On Compact Hermitian Manifolds with Flat Gauduchon Connections

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Acta Mathematica Sinica,English Series 2018年第8期34卷 1259-1268页

作者： Bo YANG fang Yang zheng School of Mathematical Sciences Xiamen University Xiamen 361005 P. R. China Department of Mathematics Zhejiang Normal University Jinhua 321004 P. R. China Department of Mathematics The Ohio State University 231 West 18th Avenue Columbus OH 43210 USA

Given a Hermitian manifold （M-n,g）, the Gauduchon connections are the one parameter family of Hermitian connections joining the Chern connection and the Bismut connection. We will call△=（1-s/2）△c＋s/2△b the s-Gauduchon connection of M, where △c and △b are respectively the Chern and Bismut connections. It is natural to ask when a compact Hermitian manifold could admit a flat s-Gauduchon connection. This is related to a question asked by Yau. The cases with s = 0 （a flat Chern connection） or s = 2 （a flat Bismut connection） are classified respectively by Boothby in the 1950s or by the authors in a recent joint work with Q. Wang. In this article, we observe that if either s 〉 4＋2√3 ≈ 7.46 or s 〈 4- 2√3≈ 0.54 and s ≠ 0, then g is Kahler. We also show that, when n = 2, g is always Kahler unless s=2. Therefore non-Kahler compact Gauduchon fiat surfaces are exactly isosceles Hopf surfaces.

关键词： Hermitian manifolds Hermitian connections Kahler manifolds

Pluriclosed Manifolds with Constant Holomorphic Sectional Curvature

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Acta Mathematica Sinica,English Series 2022年第6期38卷 1094-1104页

作者： Pei Pei RAO fang Yang zheng School of Mathematical Sciences Chongqing Normal UniversityChongqing 401331P.R.China

A long-standing conjecture in complex geometry says that a compact Hermitian manifold with constant holomorphic sectional curvature must be Kèahler when the constant is non-zero and must be Chern flat when the constant is *** conjecture is known in complex dimension 2 by the work of Balas-Gauduchon in 1985(when the constant is zero or negative)and by Apostolov±Davidov±Muskarov in 1996(when the constant is positive).For higher dimensions,the conjecture is still largely *** this article,we restrict ourselves to pluriclosed manifolds,and confirm the conjecture for the special case of Strominger Kèahler-like manifolds,namely,for Hermitian manifolds whose Strominger connection(also known as Bismut connection)obeys all the Kaèhler symmetries.

关键词： Pluriclosed manifold Hermitian manifold Strominger connection holomorphic sectional curvature

Synthesis of a Photochromic Bisphenoxynaphthacenequinone Compound by Two-step Method

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Journal of Materials Science & Technology 1999年第2期15卷 190-192页

作者： fang, zheng Liu, Jingyu Fu, Liangshe Xu, Suxian fang, Tianru Chinese Acad Sci Changchun Inst Appl Chem Changchun 130022 Peoples R China

A new photochromic bisphenoxynaphthacenequinone compound, 6,6 prime - [1-methylethylidenebis (4,1-phenyleneoxy)] bis (5,12-naphthacenequinone) (1), was synthesized by a two-step method, i.e., synthesis of 6 [4-(2-(4-hydroxyphenyl) isopropyl) phenoxy)-5, 12-naphthacenequinone (2) from 6-chloro-5, 12-naphthacenequinone (3) and bisphenol-A, and a further reaction of compound 2 in DMF/acetone mixed solvent in the presence of anhydrous potassium carbonate and potassium iodide. The crude product was obtained in a precipitate form and can easily be purified by recrystallization. The solvent composition has marked influence on the yield of the precipitated crude product in the second step. (Edited author abstract) 3 Refs.

关键词： Light sensitive materials

Photo-degradation of Acid-red 3B dye catalyzed by TiO_2 nanotubes

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Journal of Environmental Sciences 2006年第4期18卷 783-787页

作者： JIANG fang zheng Shou-rong zheng zheng XU Zhao-yi WANG Yan-jin State Key Laboratory of Pollution Control and Resource Reuse School of the Environment Nanjing University Nanjing 210093 China

TiO2 nanotube precursor was synthesized by the hydrothermal reaction of TiO2 powders with NaOH solution and the properties of the nanotube materials were tuned using different post-treatments. Transmission electron microscopic （TEM） observation revealed that the nanotube could be obtained by either a direct rinse with acid solution or rinse with distilled water followed by acid solution. The results of X-ray diffraction （XRD） and inductively coupled plasma （ICP） analysis indicated that the nanotube material was composed of H2Ti2O5·H2O. In addition, the photocatalytic activities of the resulting catalysts were found to be strongly dependent on the post-treatment. The results of the photocatalytic reaction showed that the degradation of Acid-red 3B dye fitted pseudo-zero-order kinetics and TiO2 nanotube prepared under direct rinse with acid solution exhibited a higher catalytic efficiency compared to other catalysts.

关键词： TiO2 nanotube Acid-red 3B photocatalysis hydrothermal reaction

Scaling p_T Distribution in Small Rapidity Region and Pseudorapidity Asymmetry for Charged Hadron in d+Au Collisions at (S_(NN))^(1/2)=200 GeV

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Communications in Theoretical Physics 2008年第6期49卷 1580-1582页

作者： zheng fang-Lan YANG Chun-Bin Institute of Particle Physics Huazhong Normal University Wuhan 430079 China

With the experimental data from STAR program on the centrality dependence of the PT spectra of charged hadron produced in d＋Au collisions at √^8NN=200 GeV, we show that there also exists a scaling distribution in the backward rapidity regions. Using this scaling distribution, we get the theoretical psedorapidity asymmetry which is basically in agreement with STAR data in the regions of 0≤｜η｜≤0.5 and 0.5 ≤｜η｜≤1. No theoretical models are used in any part of this phenomenological analysis.

关键词： scaling distribution pseudorapidity asymmetry

Analysis of the Yrast Bands with q-Deformed Moment of Inertia

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Chinese Physics Letters 2001年第2期18卷 193-195页

作者： fang Xiang-zheng RUAN Tu-Nan CCAST(World Lab.)P.O.Box 8730 Beijing 100080 Department of Physics Anhui UniversityHefei 230039(mailing address)University of Science and Technology of ChinaHefei 230027 Department of Modern Physics University of Science and Technology of ChinaHefei 230027

The rigid-rotor with a q-deformed moment of inertia is introduced to describe the nuclear rotational *** the representations of quantum algebra,the normal deformed and superdeformed bands are naturally differentiated by *** yrast normal deformed bands in rare earth and actinium regions,as well as the yrast superdeformed bands in A-190 and 150 regions are *** calculated results agree with experimental data qualitatively well,and the values of the parameters are physically *** indicates that the fixed deformation,the stretching effect and the many body statistics effect are three possible dominant factors to govern nuclear rotational bands.

关键词： bands deformed rotational