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Numerical simulation of hypersonic thermochemical nonequilibrium flows using nonlinear coupled constitutive relations

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Chinese Journal of Aeronautics 2023年第3期36卷 63-79页

作者： Shuhua ZENG Zhenyu YUAN wenwen ZHAO Weifang CHEN School of Aeronautics and Astronautics Zhejiang UniversityHangzhou 310027China School of Energy and Power Engineering Nanjing University of Science and TechnologyNanjing 210094China

To predict aeroheating performance of hypersonic vehicles accurately in thermochemical nonequilibrium flows accompanied by rarefaction effect,a Nonlinear Coupled Constitutive Relations(NCCR)model coupled with Gupta’s chemical models and Park’s two-temperature model is firstly proposed in this *** typical cases are intensively investigated for further validation,including hypersonic flows over a two-dimensional cylinder,a RAM-C II flight vehicle and a type HTV-2 flight *** results predicted by NCCR solution,such as heat flux coefficient and electron number densities,are in better agreement with those of direct simulation Monte Carlo or flight data than Navier-Stokes equations,especially in the extremely nonequilibrium regions,which indicates the potential of the newly-developed solution to capture both thermochemical and rarefied nonequilibrium *** comparisons between the present solver and NCCR model without a two-temperature model are also conducted to demonstrate the significance of vibrational energy source term in the accurate simulation of high-Mach flows.

关键词： Hypersonic flow Nonlinear coupled constitutive relations Rarefied gas Thermochemical nonequilibrium effect Vibrational excitation

α-Ketoglutarate dehydrogenase(KGDH):A new balancer between energy metabolism and gene expression in plants

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Journal of Integrative Plant Biology 2023年第8期65卷 1843-1845页

作者： wenwen Zhu Yikun He College of Life Sciences Capital Normal UniversityBeijing 100048China

Sessile plants can adjust their growth and development in response to environmental ***(light),is the primary source of energy for all life on the earth,in the long course of phylogenetic evolution,plants have developed a unique relationship with light:they can absorb light energy and convert it into organic matter for use by themselves and others。

关键词： energy metabolism convert

Towards geospatial semantic search:exploiting latent semantic relations in geospatial data

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International Journal of Digital Earth 2014年第1期7卷 17-37页

作者： wenwen Li Michael FGoodchild Robert Raskin GeoDa Center for Geospatial Analysis and Computation School of Geographical Science and Urban PlanningArizona State UniversityTempeAZUSA Center for Spatial Studies(Spatial@UCSB) University of CaliforniaSanta BarbaraCAUSA NASA Jet Propulsion Laboratory PasadenaCAUSA

This paper reports our efforts to address the grand challenge of the Digital Earth vision in terms of intelligent data discovery from vast quantities of geo-referenced *** propose an algorithm combining LSA and a Two-Tier Ranking(LSATTR)algorithm based on revised cosine similarity to build a more efficient search engine-Semantic Indexing and Ranking(SIR)-for a semantic-enabled,more effective data *** addition to its ability to handle subject-based search,we propose a mechanism to combine geospatial taxonomy and Yahoo!GeoPlanet for automatic identification of location information from a spatial query and automatic filtering of datasets that are not spatially *** metadata set,in the format of ISO19115,from NASA's SEDAC(Socio-Economic Data Application Center)is used as the corpus of *** show that our semantic search engine SIR built on LSATTR methods outperforms existing keyword-matching techniques,such as Lucene,in terms of both recall and ***,the semantic associations among all existing words in the corpus are *** associations provide substantial support for automating the population of spatial *** expect this work to support the operationalization of the Digital Earth vision by advancing the semantic-based geospatial data discovery.

关键词： ontology geospatial semantics search engine Digital Earth similarity search effectiveness

Saltation and suspension of wind-blown particle movement

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Science China(Physics,Mechanics & Astronomy) 2008年第10期51卷 1586-1596页

作者： WANG Ping ZHENG Xiaojing HU wenwen Key Laboratory of Mechanics on Disaster and Environment in Western China Ministry of EducationLanzhou UniversityLanzhou 730000China

Several factors that affect the trajectories of sand particles in a wind-blown sand flux are analyzed by considering the stochastic movement of sand particles transported within turbulent flow in the atmospheric boundary layer. The results show that there are remarkably different trajectories for particles with the same diameter, the same vertical liftoff velocity from sand bed and the same friction ve-locity of wind because of the presence of turbulence flow. The vertical fluctuating velocity of sand particles can be regarded as a reflection of the transport mode, which is related to not only the diameters and liftoff velocity of sand particles but also the shear stress velocity of wind. The critical liftoff velocity and the fraction of each transport mode are calculated for the given particle diameter and friction ve-locity of wind. A comparison of the predicted fraction and the statistical fraction with and without the wind-sand couple effect is made.

关键词： wind erosion saltation suspension stochastic model criterion

Whole-tissue 3D imaging reveals intra-adipose sympathetic plasticity regulated by NGF-TrkA signal in cold-induced beiging

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Protein & Cell 2018年第6期9卷 527-539页

作者： Ying Cao Huanhuan Wang wenwen Zeng Center for Life Sciences Tsinghua University Beijing 100084 China Institute for Immunology and School of Medicine Tsinghua University Beijing 100084 China Beijing Key Laboratory for Immunological Research on Chronic Diseases Beijing 100084 China Academy for Advanced Interdisciplinary Studies Peking University Beijing 10()8:71 China School of Life Sciences Peking University Beijing 100871 China

Sympathetic arborizations act as the essential efferent signals in regulating the metabolism of peripheral organs including white adipose tissues （WAT）. However, whether these local neural structures would be of plastic nature, and how such plasticity might participate in specific metabolic events of WAT, remains largely uncharacterized. In this study, we exploit the new vol- ume fluorescence-imaging technique to observe the significant, and also reversible, plasticity of intra-adi- pose sympathetic arborizations in mouse inguinal WAT in response to cold challenge. We demonstrate that this sympathetic plasticity depends on the cold-elicited sig- nal of nerve growth factor （NGF） and TrkA receptor. Blockage of NGF or TrkA signaling suppresses intra- adipose sympathetic plasticity, and moreover, the cold- induced beiging process of WAT. Furthermore, we show that NGF expression in WAT depends on the cate- cholamine signal in cold challenge. We therefore reveal the key physiological relevance, together with the reg- ulatory mechanism, of intra-adipose sympathetic plas- ticity in the WAT metabolism.

关键词： sympathetic plasticity NGF TrkA receptor cold-induced beiging whole-tissue 3D imaging

Quantifying Dynamical Predictability:the Pseudo-Ensemble Approach

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Chinese Annals of Mathematics,Series B 2009年第5期30卷 569-588页

作者： Jianbo GAO wenwen TUNG jing HU PMB Intelligence LLC PO Box 2077 West Lafayette IN 47996 USA. Purdue Climate Change Research Center Department of Earth and Atmospheric Sciences Purdue University 550 Stadium Mall Dr. West Lafayette IN 47907-2051 USA. PMB Intelligence LLC PO Box 2077 West Lafayette IN 47996 USA Affymetrix Inc. 3380 Central Expressway Santa Clara CA 95051 USA.

The ensemble technique has been widely used in numerical weather prediction and extended-range *** approaches to evaluate the predictability using the ensemble technique can be divided into two major *** is dynamical,including generating Lyapunov vectors,bred vectors,and singular vectors,sampling the fastest error-growing directions of the phase space,and examining the dependence of prediction efficiency on ensemble *** other is statistical,including distributional analysis and quantifying prediction utility by the Shannon entropy and the relative ***,with simple models,one could choose as many ensembles as possible,with each ensemble containing a large number of *** the forecast models become increasingly complicated,however,one would only be able to afford a small number of ensembles,each with limited number of members,thus sacrificing estimation accuracy of the forecast *** uncover connections between different information theoretic approaches and between dynamical and statistical approaches,we propose an (∈;T)-entropy and scale-dependent Lyapunov exponent——based general theoretical framework to quantify information loss in ensemble *** importantly,to tremendously expedite computations,reduce data storage,and improve forecasting accuracy,we propose a technique for constructing a large number of "pseudo" ensembles from one single solution or scalar *** pseudo-ensemble technique appears to be applicable under rather general conditions,one important situation being that observational data are available but the exact dynamical model is unknown.

关键词： Dynamical predictability Ensemble forecasting Relative entropy Kolmogorov entropy Scale-dependent Lyapunov exponent

基于柔性虚拟仿真技术的智慧实验教学平台建设

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实验科学与技术 2023年第4期21卷 132-136页

作者：白云金文闻朱圆敏吴元喜卢群伟余龙江刘亚丰华中科技大学生命科学与技术学院武汉430074

该文以信息技术与实验教学融合为背景,介绍了基于柔性设计虚拟仿真系统的智慧实验教学平台的总体框架与实施,重点阐述了柔性设计虚拟仿真系统的优势以及相关实验教学资源的建设范畴与要求,为实现高校智慧化实验教学探索出一条可供借鉴... 详细信息

该文以信息技术与实验教学融合为背景,介绍了基于柔性设计虚拟仿真系统的智慧实验教学平台的总体框架与实施,重点阐述了柔性设计虚拟仿真系统的优势以及相关实验教学资源的建设范畴与要求,为实现高校智慧化实验教学探索出一条可供借鉴的方案。

关键词：教育信息化柔性设计智慧教育实验教学教学改革

A Novel Sparse Penalty for Singular Value Decomposition

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Chinese Journal of Electronics 2017年第2期26卷 306-312页

作者： WANG Caihua LIU Juan MIN wenwen QU Aiping The State Key Laboratory of Software Engineering School of ComputerWuhan University

Singular value decomposition(SVD) is a tool widely used in data denoising,matrix approximation,recommendation system,text mining and computer vision.A ma jority of applications prefer sparse singular vectors to capture inherent structures and patterns of the input data so that the results are *** present a novel penalty for SVD to achieve *** with the traditional penalties,the proposed penalty is scale,dimensional insensitive and bounded between 0 and 1,which are in favor of controlling *** by the penalty,we provide an efficient algorithm to pro ject a vector onto a given sparse level in O(n) expected *** efficient pro jection algorithm serve as a drudge for sparse SVD(SSVD).In experiments,SSVD is efficient and could capture the latent structures and patterns of the input data.

关键词： Sparse controllable projection(SCP) Sparse singular value decomposition(SSVD) Sparse low rank matrix approximation(SLRMA)

Skeleton-Based Human Action Recognition via Screw Matrices

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Chinese Journal of Electronics 2017年第4期26卷 790-796页

作者： DING wenwen LIU Kai XU Biao CHENG Fei School of Computer Science and Technology Xidian University School of Mathematical Sciences Huaibei Normal University

With the recent advent of low-cost acquisition depth cameras, extracting 3D body skeleton has become relatively easier, which significantly lighten many difficulties in 2D videos including occlusions, shadows and background extraction, etc. Directly perceived features,for example points, lines and planes, can be easily extracted from 3D videos such that we can employ rigid motions to represent skeletal motions in a geometric *** apply screw matrices, acquired by using rotations and translations in 3D space, to model single and multi-body rigid motion. Since screw matrices are members of the special Euclidean group SE(3), an action can be represented as a point on a Lie group, which is a differentiable manifold. Using Lie-algebraic properties of screw algebra, isomorphic to se(3), the classical algorithms of machine learning in vector space can be expanded to manifold space. We evaluate our approached on three public3 D action datasets: MSR Action3 D dataset, UCF Kinect dataset and Florence3D-Action Dataset. The experimental results show that our approaches either match or exceed state-of-the-art skeleton-based human action recognition approaches.

关键词： Skeleton joints Human activity recogni tion Screw algebra Lie group Lie algebra