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PDA MEASUREMENTS OF TWO-PHASE FLOW STRUCTURE AND PARTICLE DISPERSION FOR A PARTICLE-LADEN JET IN CROSSFLOW

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Journal of Hydrodynamics 2010年第1期22卷 9-18页

作者： FAN jing-yu XU Song-li WANG Dao-zeng Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China

The two-phase flow structure and particle dispersion for a dilute particle-laden jet in crossflow （JICF） were experimentally investigated by means of Phase Doppler Anemometry （PDA） measurement. The two-phase flow experiments were conducted for different flow conditions and solid particle parameters, including the ratio of the jet velocity to crossflow velocity, the particle size and mass loading. The experimental results indicate that the fine particles with the size of 70 micron and the mass loading of 0.05% have a minor influence on the mean and fluctuation velocity fields of the two-phase JICF. However, the fine particle transport by the two-phase JICF is dominantly and preferentially affected by the shear layer vortices and exhibits a somewhat enhanced dispersion as compared to the fluid. For the coarse particles with the particle size ranging from 300 micron to 700 micron and the mass loading less than 0.16%, the effect of the particle parameters on the fluid phase is associated with both the anisotropic properties of the flow field and the trajectory deviation of the settling particles from the fluid. Compared to the single-phase JICF, the two-phase JICF laden with the coarse particles is recognized to possess more pronounced mean velocity alteration and turbulence modulation of the fluid phase in the presence of the particles with the larger particle size and higher mass loading.

关键词： jet crossflow two-phase flow structure particle dispersion Phase Doppler Anemometry (PDA) measurement

Uplink resource allocation in OFDMA system using distributed antennas

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Science China(Information Sciences) 2013年第12期56卷 297-302页

作者： yan JiLei li JianDong ZHAO linjing SHI Hua Broadband Wireless Communications Laboratory Information Science Institute State Key Laboratory of Integrated Services Networks Xidian University

In this article,we investigate uplink resource allocation in orthogonal frequency division multiple access(OFDMA)systems that use distributed *** multiple distributed receiving antennas motivate us to exploit the spatial diversity to maximize the achievable rate of the *** constraints on the subcarrier allocation and the power limit of each user equipment(UE),a mixed-integer optimization problem is *** frst propose a centralized greedy algorithm to fnd the maximum achievable rate of the *** a heuristic algorithm is proposed that can be implemented in a distributed *** results show that the heuristic algorithm can approximately achieve the maximum achievable rate of the system and result in signifcant system performance improvement over the approach assigning one user to each subcarrier.

关键词： uplink OFDMA system distributed antennas subcarrier assignment power allocation heuristic algorithm

Microstructure and Wear Resistance of N-Doped TiO_2 Coatings Grown on Stainless Steel by Plasma Surface Alloying Technology

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Journal of Iron and Steel Research International 2011年第7期18卷 73-78页

作者： WANG He-feng TANG Bin li Xiu-yan Surface Engineering Institute Taiyuan University of Technology Taiyuan 030024 Shanxi China

N doped TiO2 （N-TiO2） coatings were obtained by oxidation of titanium nitride coatings, which were pre pared by the plasma surface alloying technique on stainless steel （SS）. The microstructure of N-TiO2 coatings was characterized by X-ray diffraction （XRD）, glow discharge optical emission spectrometry （GDOES）, X-ray photoelectron spectroscopy （XPS） and scanning electron microscopy （SEM）, respectively. Ball-on-disc sliding wear was applied to test and compare the tribological behaviors of the coatings and substrate. XRD patterns showed that anatase type TiO2 existed in the coatings after oxidation. GDOES showed that the resultant coatings had a layered structure, comprising of N-TiO2 layer at the top and a diffusion-type interface. Such a hybrid coatings system showed good adhesion with the substrate. According to XPS, residual N atoms partially occupied O atom sites in the TiO2 lattice. Uniform, continuous and compact coatings were observed by SEM images of coatings after oxidation. Under a load of 7.6 N, the coefficient of friction was in the range of 0.27--0.38 for the N-TiO2/Al2O3 systems and the wear rate of the coatings was only one-fourteenth of that for untreated 316L SS. N-TiO2 coatings displayed much better wear resistance and antifrietion performance than SS substrate.

关键词： plasma surface alloying technique wear resistance stainless steel titanium dioxide

Quantitative measurement of magnetic parameters by electron magnetic chiral dichroism

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Chinese Physics B 2018年第5期27卷 1-11页

作者： Dong-Sheng Song Zi-Qiang Wang Xiao-yan Zhong jing Zhu National Center for Electron Microscopy in Beijing Key Laboratory of Advanced Materials （MOE） and the State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing 100084 China

Electron magnetic circular dichroism opens a new door to explore magnetic properties by transmitted electrons in the transmission electron microscope. However, obtaining quantitative magnetic parameters, such as spin and orbital magnetic moment with element-specificity, goes a long way along with the development and improvement of this technique both in theoretical and experimental aspects. In this review, we will give a detailed description of the quantitative electron magnetic circular dichroism（EMCD） technique to measure magnetic parameters with spin-specificity, element-specificity,site-specificity, and orbital-spin-specificity. The discussion completely contains the procedures from raw experimental data acquisition to final magnetic parameters, together with the related custom code we have developed.

关键词： quantitative electron magnetic circular dichroism (EMCD) technique dynamical diffraction effects spin and orbital magnetic moment

Optimization of the MUSCL scheme by dispersion and dissipation

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Science China(Physics,Mechanics & Astronomy) 2012年第5期55卷 844-853页

作者： LENG yan li Xinliang FU DeXun MA yanWen The State Key Laboratory of High-temperature Gas Dynamics(LHD) Institute of MechanicsChinese Academy of SciencesBeijing 100190China The State Key Laboratory of Nonlinear Mechanics(LNM) Institute of MechanicsChinese Academy of SciencesBeijing 100190China

A second-order optimized monotonicity-preserving MUSCL scheme(OMUSCL2) is developed based on the dispersion and dissipation optimization and monotonicity-preserving *** new scheme(OMUSCL2) is simple in expression and is easy for use in CFD *** with the original second-order or third-order MUSCL scheme,the new scheme shows nearly the same CPU cost and higher resolution to shockwaves and small-scale *** new scheme has been tested through a set of one-dimensional and two-dimensional tests,including the Shu-Osher problem,the Sod problem,the Lax problem,the two-dimensional double Mach reflection and the RAE2822 transonic airfoil *** numerical tests show that,compared with the original MUSCL schemes,the new scheme causes fewer dispersion and dissipation errors and produces higher resolution.

关键词： MUSCL scheme monotonicity-preserving resolution dissipation/dispersion error optimization

One-Pot Polymerase Chain Reaction with Gold Nanoparticles for Rapid and Ultrasensitive DNA Detection

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Nano Research 2010年第8期3卷 557-563页

作者： Miao Cai Feng li yan Zhang Qiangbin Wang i-Lab Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123China

We report a novel method for rapid,colorimetric detection of a specific deoxyribonucleic acid(DNA)sequence by carrying out a polymerase chain reaction in the presence of gold nanoparticles functionalized with two *** of the primers when the target DNA is present as a template during the polymerase chain reaction process affords the complementary sequences on the gold nanoparticle surfaces and results in the formation of gold nanoparticle aggregates with a concomitant color change from red to pinkish/*** method provides a convenient and straightforward solution for ultrasensitive DNA detection without any further post-treatment of the polymerase chain reaction products being necessary,and is a promising tool for rapid disease diagnostics and gene sequencing.

关键词： deoxyribonucleic acid(DNA)detection polymerase chain reaction(PCR) Au nanoparticle colorimetric

The error source analysis of oil spill transport modeling: a case study

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Acta Oceanologica Sinica 2013年第10期32卷 41-47页

作者： li yan ZHU Jiang WANG Hui KUANG Xiaodi University of the Chinese Academy of Sciences Key Laboratory of Research on Marine Hazards Forecasting National Marine Environmental Forecasting CenterState Oceanic Administration Institute of Atmospheric Physics Chinese Academy of Sciences Marine Environmental Forecasting Division National Marine Environmental Forecasting CenterState Oceanic Administration

Numerical modeling is an important tool to study and predict the transport of oil spills. However, the accu- racy of numerical models is not always good enough to provide reliable information for oil spill transport. It is necessary to analyze and identify major error sources for the models. A case study was conducted to analyze error sources of a three-dimensional oil spill model that was used operationally for oil spill forecast- ing in the National Marine Environmental Forecasting Center （NMEFC）, the State Oceanic Administration, China. On June 4, 2011, oil from sea bed spilled into seawater in Penglai 19-3 region, the largest offshore oil field of China, and polluted an area of thousands of square kilometers in the Bohai Sea. Satellite remote sensing images were collected to locate oil slicks. By performing a series of model sensitivity experiments with different wind and current forcings and comparing the model results with the satellite images, it was identified that the major errors of the long-term simulation for oil spill transport were from the wind fields, and the wind-induced surface currents. An inverse model was developed to estimate the temporal variabil- ity of emission intensity at the oil spill source, which revealed the importance of the accuracy in oil spill source emission time function.

关键词： error source oil spill lagrangian random walk

Higher-order topological solitonic insulators

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npj Computational Materials 2019年第1期5卷 195-201页

作者： Zhixiong li Yunshan Cao Peng yan Xiangrong Wang School of Electronic Science and Engineering and State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China610054 ChengduChina Physics Department The Hong Kong University of Science and TechnologyClear Water BayKowloonHong Kong HKUST Shenzhen Research Institute 518057 ShenzhenChina

Pursuing topological phase and matter in a variety of systems is one central issue in current physical sciences and *** by the recent experimental observation of corner states in acoustic and photonic structures,we theoretically study the dipolar-coupled gyration motion of magnetic solitons on the two-dimensional breathing kagome *** calculate the phase diagram and predict both the Tamm–Shockley edge modes and the second-order corner states when the ratio between alternate lattice constants is greater than a critical *** show that the emerging corner states are topologically robust against both structure defects and moderate *** simulations are implemented to verify the theoretical predictions with an excellent *** results pave the way for investigating higher-order topological insulators based on magnetic solitons.

关键词： value topological insulator

BOUNDEDNESS OF MULTIliNEAR liTTLEWOOD-PALEY OPERATORS ON AMALGAM-CAMPANATO SPACES

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Acta Mathematica Scientia 2020年第1期40卷 272-292页

作者： Xiang li Qianjun HE Dunyan yan School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Applied Science Beijing Information Science and Technology UniversityBeijing 100192China

In this paper,we consider the boundedness of multilinear littlewood-Paley operators which include multilinear g-function,multilinear Lusin's area integral and multilinear littlewood-Paley g^*λ-***,norm inequalities o... 详细信息

关键词： multilinear littlewood-Paley g-function multilinear g^*λ-function AmalgamCampanato spaces