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A novel high-order scheme for numerical simulation of wake flow over helicopter rotors in hover

Chinese Journal of Aeronautics 2022年第5期35卷 260-274页

作者： Shaoqiang HAN wenping SONG Zhonghua HAN Institute of Aerodynamic and Multidisciplinary Design Optimization National Key Laboratory of Science and Technology on Aerodynamic Design and ResearchSchool of AeronauticsNorthwestern Polytechnical UniversityXi’an 710072China

Accurate prediction of tip vortices is crucial for predicting the hovering performance of a helicopter rotor.A new high-order scheme(we call it WENO-K)proposed by our research group is employed to minimize numerical dissipation and extended to numerical simulation of unsteady compressible viscous flows dominated by tip vortices over hovering ***-K is referred to as an adaptively optimized WENO scheme with Gauss-Kriging reconstruction,and its advantage is to reduce dissipation in smooth regions of flow while preserving high-resolution around *** WENO-K scheme is adopted to reconstruct left and right state values within the Roe Riemann solver updating the inviscid fluxes on a structured dynamic overset *** minimize the accuracy loss for high-order reconstruction on artificial boundaries of overset grid,a method of multilayer fringes is proposed to carry out interpolation between background grid and blade *** parallel computing considering automatic load balance on averagely partitioned overset grid is developed to reduce the wall-clock time of an unsteady *** results for Caradonna-Tung(C-T)rotor in hover at the conditions of subsonic and transonic tip Mach numbers show that the thrust coefficient error for the result of WENO-K scheme is no more than 3%.Compared with WENO-JS scheme,WENO-K scheme achieves about 40%improvement on accuracy of predicting rotor thrust with only 4.1%extra computational *** importantly,WENO-K scheme can capture more sophisticated unsteady flow structures and resolve tip vortices to a larger wake age with an increment of about 270°compared to WENO-JS scheme.

关键词： Dynamic overset grid Helicopter rotors High-order scheme Unsteady flow Vortex flow WENO scheme

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Multi-infill strategy for kriging models used in variable fidelity optimization

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Chinese Journal of Aeronautics 2018年第3期31卷 448-456页

作者： Chao SONG Xudong YANG wenping SONG National Key Laboratory of Science and Technology on Aerodynamic Design and Research Northwestern Polytechnical University

In this paper, a computationally efficient optimization method for aerodynamic design has been developed. The low-fidelity model and the multi-infill strategy are utilized in this ***-fidelity data is employed to provide a good global trend for model prediction, and multiple sample points chosen by different infill criteria in each updating cycle are used to enhance the exploitation and exploration ability of the optimization approach. Take the advantages of lowfidelity model and the multi-infill strategy, and no initial sample for the high-fidelity model is needed. This approach is applied to an airfoil design case and a high-dimensional wing design *** saves a large number of high-fidelity function evaluations for initial model construction. What＇s more, faster reduction of an aerodynamic function is achieved, when compared to ordinary kriging using the multi-infill strategy and variable-fidelity model using single infill criterion. The results indicate that the developed approach has a promising application to efficient aerodynamic design when high-fidelity analyses are involved.

关键词： Aerodynamics Infill criteria Kriging models Multi-infill Optimization

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Plasmonic materials for flexible near-infrared photovoltaic devices

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Science China Materials 2016年第6期59卷 410-411页

作者： wenping Hu Institute of Chemistry Chinese Academy of Sciences

There is no doubt that photovoltaic(PV)technologies represent a highly important approach to provide clean energy by directly converting sunlight into *** high natural abundance of silicon together with its excellent ... 详细信息

关键词： photovoltaic electricity converting doubt abundance silver enable bright clean PEDOT

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Thermodynamic modelling of the phengite geobarometry

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Science China Earth Sciences 2007年第7期50卷 1033-1039页

作者： ZHU wenping WEI ChunJing The MOE Laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space Sciences Peking University Beijing 100871 China

Using the updated models of activity-composition relations for solid solutions,P-T pseudosections and Si isopleths of phengite in the system KFMASH (K2O-FeO-MgO-Al2O3-SiO2-H2O) are calculated with the software THERMOCALC 323 for three bulk compositions of the average,Al-rich and K-rich metapelites. The Si isopleths of phengite in the calculated pseudosections are highly dependent on mineral as-semblages. In the chlorite-and biotite-bearing di-and trivariant fields,and in the garnet + kyanite-bearing trivariant fields,the phengite can be used as a good geobarometer. But in the carpho-lite-present and chlorite-absent fields,the Si contents of phengite mainly indicate variance of tem-perature. For a given Si value,the phengite in kyanite-bearing assemblages shows higher pressures than in the K-feldspar-bearing assemblages. Addition of Na2O into the KFMASH leads to reduction of stability of the AFM phases. The Si isopleths of phengite in the mineral assemblages containing only one Na-phase are similar to those in the corresponding KFMASH assemblages. But in the assemblages with two or more Na-phases,the phengite Si isopleths differ remarkably from those in the KFMASH.

关键词： P-T pseudosection phengite geobarometry

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Insight into the Effect of Metal Cations in the Electrolyte on Performance for Electrocatalytic CO_(2)Reduction Reaction

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Energy & Environmental Materials 2022年第4期5卷 1008-1009页

作者： Junjun Li Zhicheng Zhang wenping Hu Tianjin Key Laboratory of Molecular Optoelectronic Sciences Department of ChemistrySchool of ScienceTianjin University&Collaborative Innovation Center of Chemical Science and EngineeringTianjin 300072China

This highlight indicates that the local electrostatic interactions between metal cations and key intermediates facilitate the electrocatalytic CO_(2) reduction *** CO_(2) reduction reaction(CO_(2)RR)has been considere... 详细信息

关键词： CO_(2)reduction reaction electrocatalysis metal cations

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Feature-Based Trajectory Privacy Preserving via Low-Rank and Sparse Decomposition

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Chinese Journal of Electronics 2018年第4期27卷 746-755页

作者： LI wenping DENG Kun YU Fahong College of Mathematics Physics and Information Engineering Jiaxing University

The disclosure of sensitive contents hidden in trajectories may jeopardize individuals’ privacy *** privacy preserving technologies on trajectories face the challenge of how to give consideration to the spatiotemporal structure of mobile data. Traditional trajectory privacy preserving tricks focus chiefly on partial structure,while ignoring global feature of trajectories. This research orientation tends to cause exorbitant distortion on the spatiotemporal structure of trajectories, which may give rise to low data utility. The moving behavior has itself innate sparseness feature. Thus a trajectory privacy preserving method based on feature maintaining is proposed by introducing the low-rank and sparse decomposition technique about large matrix. The proposed method iteratively decompose the feature matrix until the rank achieving stability to extract the primary feature and eliminate the private parts. The released trajectories are reconstructed by perturbing the final refined feature matrix with a series of low-rank components generated in the decomposition procedure. Experimental results on real-world dataset verified that the proposed method has low information loss on large-scale data.

关键词： Privacy preserving Trajectory Low-rank and sparse decomposition Feature

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SHRIMP U-Pb Zircon Age of the Ka'erjiao Intrusion in the Sawur Region in West Junggar,Xinjiang

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Acta Geologica Sinica(English Edition) 2007年第2期81卷 322-329页

作者： ZHOU Taofa TAN Lugui FAN Yu YUAN feng YANG wenping HE Lixin YUE Shucang School of Resources and Environmental Engineering Hefei University of Technology Hefei Anhui 230009 No. 4 Geological Party Xinjiang Bureau of Geological Exploration Altay Xinjiang 836500

Acid intrusions are widespread in the Sawur region, Xinjiang. The Ka＇erjiao intrusion is mainly composed of albite granite porphyry, K-feldspar granite porphyry, ivernlte and granite porphyry. Being a transitional product between magma intrusion and eruption in the Sawur region, the Ka＇erjiao intrusion was formed at the telophase of the late Carboniferous to the begining of early Permian as determined by the SHRIMP U-Pb zircon dating, with an age of 302.6±7.6 Ma （1 σ）. The intrusion consists of alkali-enriched rock, whose REE distribution patterns are of the LREE enrichment type, the δEu value is low and Nd, St, Pb isotopes reflect its mantle source characteristics. The δ^18O value of intrusion is low as a result of isotope exchange with meteoric water. The geochemical characteristics show that it was formed in a post-collisional tectonic setting. Taking combined considerations of current studies of A-type granites and Permian volcanic rocks, we think that in the telophase of the late Carboniferous to the beginning of the early Permian, the Sawur region was within the extension or compressional to extensional period of a post-collisionai stage. The Ka＇erjiao intrusion from mantle sources can confirm the vertical continental crust growth in the late Paleozoic. The Sawur region in west Junggar is consistent with east Junggar in post-collisionai tectonic evolution process.

关键词： granite zircon SHRIMP data post-collision Sawur region Xinjiang

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Phase transitions in two organic salts based on 1,5-naphthalenedisulfonate

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Science China Chemistry 2016年第1期59卷 114-121页

作者： wenping Zhao Yu Jin Wen Zhang Ordered Matter Science Research Center Southeast University

Two phase transition compounds,diethylammonium 1,5-naphthalenedisulfonate(1)and cyclohexylammonium 1,5-naphthalenedisulfonate(2),were screened from a series of organic salts based on 1,*** phase transition behaviors were studied by differential scanning calorimetry,single-crystal X-ray analysis and dielectric *** 1 and 2 undergo phase transitions at about 202 and 148 K,respectively,accompanied by distinct dielectric *** origin of the phase transitions was ascribed to motional changes of the cations in the crystal lattices.

关键词： phase transition dielectric constant naphthalenedisulfonate organic salt

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Numerical simulation of sedimentation of rectangular particle in Newtonian fluid

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Particuology 2012年第1期10卷 79-88页

作者： Hong Lv Shengli Tang wenping Zhou Department of Power Engineering Chongqing University Chongqing 400030 PR China

The sedimentation of a rectangular particle falling in a two-dimensional channel filled with Newtonian fluid was simulated with finite element arbitrary Lagrangian-Eulerian domain method. The numerical procedure was validated by comparison of the simulation results with existing numerical work. Morea over, good agreement was obtained between the simulation results and experimental measurements performed in the current study. The equilibrium position, stable orientation and drag coefficient ofa rect- angular particle for different particle Reynolds numbers （Rep） were studied. The results show that there is a critical particle Reynolds number for the preferred orientation of a rectangular particle falling in a Newtonian fluid. When Rep is smaller than the critical value, the particle fails with its long side parallel to gravity; otherwise the particle fails with its long side perpendicular to gravity. The critical particle Reynolds number is a decreasing function of the blockage ratio and aspect ratio. The distributions of pressure and shear stress on rectangular particle surface were analyzed. Moreover, the drag coefficient of the rectangular particle decreases as Rep or the blockage ratio increases; however, it appears to be independent of aspect ratio.

关键词： Rectangular particleDrag coefficientSedimentationALE methodDirect numerical simulation

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Sampling Streaming Data Along Geodesic

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Chinese Journal of Electronics 2015年第2期24卷 251-257页

作者： LI wenping YANG Jing ZHANG Jianpei College of Computer Science and Technology Harbin Engineering University College of Mathematics Physics and Information Engineering Jiaxing University

This paper proposes an approach to sample data stream based on differential geometry. Our aim is to take advantage of information of discarded data and support stream to generate different number of transactions during different periods. To this end, we establish a novel data stream model represented by a surface, within which time is quantified and probability, value and time,viewed as one united body, could be calculated simultaneously. We pro ject data stream onto a surface of the model and replace points which have the shortest geodesic distance with their mid-point. To the best of our knowledge,this is the first work on introducing differential geometry as a sampling trick. Experimental results show that our approach is effective.

关键词： Data stream Sampling Data stream model Differential geometry Geodesic

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