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Flow Characteristics and Aerodynamic Heating of Tube Trains in Choked/Unchoked Flow:A Numerical Study

Journal of Thermal Science 2023年第4期32卷 1421-1434页

作者： sui yang YU Qiujun NIU Jiqiang CAO Xiaoling yang Xiaofeng YUAN Yanping Graduate School of Tangshan Southwest Jiaotong UniversityTangshan063000China School of Mechanical Engineering Southwest Jiaotong UniversityChengdu610031China State Key Laboratory of Aerodynamics China Aerodynamics Research and Development CenterMianyang621000China

Hyperloop has become one of the key reserve technologies for future high-speed rail *** gas in the tube is compressed and rubbed,leading to a strong aerodynamic heating *** research on the flow field characteristics and aerodynamic heating effect of hyperloop is in its infancy,and that on the flow field structure is *** this study,the nozzle theory was used to make a preliminary judgment on the choked flow phenomenon in the *** on the flow results obtained under different working conditions,the identification basis of the choked flow phenomenon in the hyperloop was ***,the effect of the choked/unchoked flow on the flow structure,temperature,and pressure distribution of the annular space in the tube was *** on traditional high-speed railway aerodynamics,according to relevant theories and calculation in aerospace field,and combined with the model test data,the reliability verification analysis on the characteristics of the flow field are carried *** structure of the flow filed in the tube can be divided into choked and *** judgment is dependent on whether the throat reaches the speed of *** the choked flow,a normal shock wave is formed in front of the tube *** temperature rise of the local flow field exceeds 50 K;the temperature rise of the stagnation region exceeds 88 K,and the pressure is approximately 1.7 times that of the initial pressure in the *** the flow is unchoked,differences arise in the distribution of the flow field corresponding to different incoming Mach *** the incoming flow is supersonic,the flow field maintains a supersonic speed,and a bow-shaped shock wave is formed at the front of the tube *** to the shock wave or expansion wave,the local flow field exhibits significant fluctuations in temperature and ***,when the incoming flow is subsonic,the flow field in the tube maintains a subsonic speed,and no shock wave structure is

关键词： hyperloop choked/unchoked flow aerodynamic phenomenon numerical simulation

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GliomaDB: A Web Server for Integrating Glioma Omics Data and Interactive Analysis

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Genomics, Proteomics & Bioinformatics 2019年第4期17卷 465-471页

作者： Yadong yang yang sui Bingbing Xie Hongzhu Qu Xiangdong Fang CAS Key Laboratory of Genome Sciences and Information Beijing Institute of GenomicsChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

Gliomas are one of the most common types of brain *** efforts have been devoted to studying the mechanisms of glioma genesis and identifying biomarkers for diagnosis and *** help further investigations,we present a comprehensive database named *** includes 21,086 samples from 4303 patients and integrates genomic,transcriptomic,epigenomic,clinical,and gene-drug association data regarding glioblastoma multiforme(GBM)and low-grade glioma(LGG)from The Cancer Genome Atlas(TCGA),Gene Expression Omnibus(GEO),the Chinese Glioma Genome Atlas(CGGA),the Memorial Sloan Kettering Cancer Center Integrated Mutation Profiling of Actionable Cancer Targets(MSK-IMPACT),the US Food and Drug Administration(FDA),and Pharm *** offers a user-friendly interface for two main types of *** first comprises queries of(i)somatic mutations,(ii)gene expression,(iii)microRNA(miRNA)expression,and(iv)DNA *** addition,queries can be executed at the gene,region,and base ***,GliomaDB allows users to perform survival analysis,coexpression network visualization,multi-omics data visualization,and targeted drug recommendations based on personalized *** bridges the gap between glioma genomics big data and the delivery of integrated information for end users,thus enabling both researchers and clinicians to effectively use publicly available data and empowering the progression of precision medicine in *** is freely accessible at http://***/glioma DB.

关键词： Database Variations Methylation Network Survival analysis

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An Aerothermal Study of Influence of Blockage Ratio on a Supersonic Tube Train System

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Journal of Thermal Science 2022年第2期31卷 529-540页

作者： sui yang NIU Jiqiang YUAN Yanping YU Qiujun CAO Xiaoling WU Dan yang Xiaofeng School of Mechanical Engineering Southwest Jiaotong UniversityChengdu 610031China School of Architecture and Design Southwest Jiaotong UniversityChengdu 610031China State Key Laboratory of Aerodynamics China Aerodynamics Research and Development CenterMianyang 621000China

Evacuated tube transportation is an important development direction for the high-speed transportation technology of the ***,a train running at supersonic speed in a closed tube can create an unstable aerothermal phenomenon,causing the temperature to rise sharply inside the tube and endangering the safe operation of trains and *** blockage ratio is one of the key factors affecting the aerodynamic characteristics in the *** this paper,a 2 D axisymmetric model and Delayed Detached Eddy Simulation(DDES)based on the Shear Stress Transport(SST)k-ωturbulence model are used to study the aerothermal environment in the *** calculation method used in this paper was verified by a wind tunnel *** aerothermal phenomenon and distribution of the flow field in the tube with different blockage ratios were compared and *** results show that the aerothermal environment is significantly affected by the blockage ratio.A choking limit formed in the flow field will aggravate the aerodynamic phenomenon as the blockage ratio increases,which further deteriorates the aerothermal environment of the ***,the existence of the choking limit,shock wave,and Mach disk make the flow field in the tube more complicated.

关键词： tube train aerothermal environment blockage ratio choking limit numerical simulation

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Origin of Baotoudong syenites in North China Craton:Petrological, mineralogical and geochemical evidence

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Science China Earth Sciences 2016年第1期59卷 95-110页

作者： NIU Xiao Lu yang Jing sui LIU Fei ZHANG Hong Yu yang Ming Chun State Key Laboratory of Continental Tectonics and Dynamics Institute of Geology Chinese Academy of Geological Sciences Institute of Earth Sciences China University of Geosciences Key Laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space Sciences Peking University

Baotoudong syenite pluton is located to the east of Baotou City, Inner Mongolia, the westernmost part of the Trias- sic alkaline magmatic belt along the northern margin of the North China Craton （NCC）. Zircon U-Pb age, petrological, miner- alogical and geochemical data of the pluton were obtained in this paper, to constrain its origin and mantle source characteris- tics. The pluton is composed of nepheline-clinopyroxene syenite and alkali-feldspar syenite, with zircon U-Pb age of 214.7±1.1 Ma. Diopside （cores）-aegirine-augite （rims）, biotite, orthoclase and nepheline are the major minerals. The Bao- toudong syenites have high contents of rare earth elements （REE）, and are characterized by enrichment in light rare earth ele- ments （LREE） and large ion lithophile elements （LILE; e.g., Rb, Ba, Sr）, depletion in heavy rare earth elements （HREE） and high field strength elements （HFSE）. They show enriched Sr-Nd isotopic compositions with initial 87Sr/86Sr ranging from 0.7061 to 0.7067 and eNd（t） values from -9.0 to -11.2. Mineralogy, petrology and geochemical studies show that the parental magma of the syenites is SiO2-undersaturated potassic-ultrapotassic, and is characterized by high contents of CaO, Fe2O3, K2O, Na2O and fluid compositions （H2O）, and by high temperature and high oxygen fugacity. The syenites were originated from a phlogopite-rich, enriched lithospheric mantle source in garnet-stable area （〉80 km）. The occurrence of the Baotoudong sye- nites, together with many other ultrapotassic, alkaline complexes of similar ages on the northern margin of the NCC in Late Triassic implies that the lithospheric mantle beneath the northern margin of the NCC was previously metasomatized by melts/fluids from the subducted, altered paleo-Mongolian oceanic crust, and the northern margin of the craton has entered into an extensively extensional regime as a destructive continental margin in Late Triassic.

关键词： Zircon U-Pb age Mineralogy Geochemistry Baotoudong syenites Ultrapotassic alkaline rocks Triassic Mantlemetasomatism North China Craton

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International financial crisis and wage inequality in urban China

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Economic and Political Studies 2017年第3期5卷 342-357页

作者： sui yang Shi Li Rural Development Institute Chinese Academy of Social SciencesBeijingChina School of Economics and Management Beijing Normal UniversityBeijingChina

The shock of the 2007/2008 international financial crisis had a negative impact on the Chinese economy at its early stage,but the immediate reaction of the Chinese government with a stimulus package of 4 trillion yuan has recovered this economy *** the crisis and the governmental stimulus package have generated different impacts on unemployment and wage growth across regions and industries,it will lead to some changes in the pattern of wage *** paper uses urban household data collected from RUMiC surveys during 2008–2010 to investigate changes in wage growth and inequality in urban China in this *** findings indicate that the international financial crisis did not have significantly negative impact on wage growth and contributed to narrowing wage inequality in urban China,which was largely due to offsetting effects of the governmental stimulus ***,as the impact of the stimulus policies faded and the impact of the international financial crisis worsened,the wage growth experienced a downward trend and wage inequality rose in 2010.

关键词： Financial crisis wage growth wage inequality urban China

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Observation of acoustic spin

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National Science Review 2019年第4期6卷 707-712页

作者： Chengzhi Shi Rongkuo Zhao yang Long sui yang Yuan Wang Hong Chen Jie Ren Xiang Zhang NSF Nano-scale Science and Engineering Center (NSEC) University of CaliforniBerkeley George W.Woodruff School of Mechanical Engineering Georgia Institute of Technology NSF Nano-scale Science and Engineering Center (NSEC) University of CaliforniaBerkeley Center for Phononics and Thermal Energy Science China-EU Joint Center for Nanophononics Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology School of Physics Sciences and Engineering Tongji University Faculties of Science and Engineering University of Hong Kong

Unlike optical waves, acoustic waves in fluids are described by scalar pressure fields, and therefore are considered spinless. Here, we demonstrate experimentally the existence of spin in acoustics. In the interference of two acoustic waves propagating perpendicularly to each other, we observed the spin angular momentum in free space as a result of the rotation of local particle velocity. We successfully measured the acoustic spin, and spin-induced torque acting on a designed lossy acoustic probe that results from absorption of the spin angular momentum. The acoustic spin is also observed in the evanescent field of a guided mode traveling along a metamaterial waveguide. We found spin–momentum locking in acoustic waves whose propagation direction is determined by the sign of spin. The observed acoustic spin could open a new door in acoustics and its applications for the control of wave propagation and particle rotation.

关键词： acoustic spin spin-induced torque spin–momentum locking

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Social insurance for migrant workers in China:impact of the 2008 Labour Contract Law

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Economic and Political Studies 2017年第3期5卷 285-304页

作者： Qin Gao sui yang Shi Li School of Social Work Columbia UniversityNew YorkNY 10027USA Rural Development Institute Chinese Academy of Social SciencesBeijingChina Business School Beijing Normal UniversityBeijingChina

Using the China Household Income Project(CHIP)2007,2008,and 2009 longitudinal migrant survey data,this article provides new evidence on the effects of China’s 2008 Labour Contract Law(LCL)on migrant workers’social insurance participation,including in pensions,work injury insurance,unemployment insurance,medical insurance,and the housing provident *** find consistently strong evidence that migrant workers’labour contract status was significantly associated with their participation in all five types of social *** particular,having or gaining a long-term contract helped promote migrant workers’social insurance participation,while losing one such contract decreased their chance of social insurance *** a difference-in-differences(DID)method and focussing on the panel sample,we find that the implementation of the LCL helped boost migrant workers’chance of social insurance participation consistently and significantly,especially for those who gained a long-term *** findings suggest that the LCL at least partly reached its intended policy goal of improving social protection for migrant workers,a disadvantaged group in the Chinese labour *** research should use longitudinal data and rigorous methods to track the long-term impact of this important law and help build a strong,unified social insurance system for all Chinese citizens.

关键词： China Labour Contract Law migrant workers social insurance difference-indifferences

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Aerodynamics of railway train/tunnel system:A review of recent research

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Energy and Built Environment 2020年第4期1卷 351-375页

作者： Jiqiang Niu yang sui Qiujun Yu Xiaoling Cao Yanping Yuan School of Mechanical Engineering Southwest Jiaotong UniversityChengdu 610031SichuanChina

The coupling and complexity of railway train/tunnel system are further aggravated by increasing train speed,which produces a series of aerodynamics problems,such as aerodynamic drag,slipstream,pressure wave and micro pressure *** effects of tunnels will result in a significant increase in train energy consump-tion,shorten life of railway train/tunnel system,and increase maintenance *** paper provides a review of aerodynamics of railway train/tunnel *** in railway train/tunnel system aerodynamics and their related factors are discussed *** performance and flow field characteristics of trains in tunnels are *** of aerodynamic effects and parameters of railway train/tunnel system,and the control methods for reducing aerodynamic effects in tunnels are explained.A traffic safety evaluation of the train in tunnels,such as vehicle body structure,passengers’ear comfort,etc.,is introduced and ***,future outlooks and research topics are proposed.

关键词： High-speed trains Tunnel aerodynamics Compressible flow

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Trade and Rural-Urban Income Inequality： Evidence from China

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Frontiers of Economics in China-Selected Publications from Chinese Universities 2012年第4期7卷 519-543页

作者： Hao Wei sui yang Haoji Huang School of Economics-and Business Administration Beijing Normal University Beijing100875 China

Using the provincial panel data from 1978 to 2007, this paper makes an empirical analysis of the relationship between international trade and rural-urban income inequality in China. The results show that international trade has a fundamental impact on rural-urban income inequality. For the whole country, the development of international trade from 1978 to 2007 enlarged the rural-urban income gap. During the three different periods （defined in section 3.3）, the impact was also noticeable in terms of extent, direction and significance respectively at the national and regional levels. During the three periods, the relationship has an inverted ＂U＂ shape for China as a whole, central China and western China, but for eastern China the relationship has a ＂U＂ shape. At the same time, exports and imports have different influences on the rural-urban income gap in China, the influences were also different across regions; and the imports has had a more significant influence on these regions than exports has had.

关键词： China trade imports exports rural-urban income gap

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Electron-hole hybridization in bilayer graphene

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National Science Review 2020年第2期7卷 248-253页

作者： Siqi Wang Mervin Zhao Changjian Zhang sui yang Yuan Wang Kenji Watanabe Takashi Taniguchi James Hone Xiang Zhang NSF Nanoscale Science and Engineering Center (NSEC) University of California Materials Sciences Division Lawrence Berkeley National Laboratory Department of Mechanical Engineering Columbia University National Institute for Materials Science Faculties of Sciences and Engineering University of Hong Kong

Band structure determines the motion of electrons in a solid, giving rise to exotic phenomena when properly engineered. Drawing an analogy between electrons and photons, artificially designed optical lattices indicate the possibility of a similar band modulation effect in graphene systems. Yet due to the fermionic nature of electrons, modulated electronic systems promise far richer categories of behaviors than those found in optical lattices. Here, we uncovered a strong modulation of electronic states in bilayer graphene subject to periodic potentials. We observed for the first time the hybridization of electron and hole sub-bands, resulting in local band gaps at both primary and secondary charge neutrality points. Such hybridization leads to the formation of flat bands, enabling the study of correlated effects in graphene systems. This work may provide a novel way to manipulate electronic states in layered systems, which is important to both fundamental research and application.

关键词： band modulation periodic potential bilayer graphene

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