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Flow Instability and Its Control in Compression Systems

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Journal of Thermal Science 2003年第1期12卷 1-9页

作者： Jingyi ChenInstitute of Engineering Thermophysics, chinese academy of sciences. beijing 100080, china Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing China

This paper reviews the development in the research of flow instability and its control over the recent ten or more years. This development was largely stimulated by the novel idea of active control of the aerodynamic instability in compressors. Three topics are covered in the paper, which appeared as the major themes towards the goal of stability enhancement. The first topic is the pre-stall behavior of rotating stall, which plays a vital role in designing the control scheme and discovering the convenient route to find the causal factors of flow disturbances potentially leading to stall. The second topic is the mechanism of blade passage flow during stall and its inception, which is the basic knowledge needed to manipulate the blade design for the stability improvement and eventually to predict the unsteady performance of the compressor system. The third topic is the recent trend of the control strategy based on the learning of active vs. passive methods. To introduce to the discussion of these topics, a brief description of the history of the recent development is given at the beginning of the paper. In discussing each topic, future works are also highlighted to enhance the further development of this long-standing problem in turbomachinery research and application.

关键词： compressors rotating stall pre-stall active/passive control wavelet.

THREEDIMENSIONAL NUMERICAL SIMULATION OF WINDINDUCED CIRCULATION IN LAKE TAIHU

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Journal of Hydrodynamics 2004年第3期16卷 341-349页

作者： LUOLian-cong QINBo-qiang NanjingInstituteofGeographyandLimnology ChineseAcademyofSciencesNanjing210008China

A three-dimensional (3-D) numerical circulation model for shallow-lake ispresented and described in detail in this paper, which employs model-splitting technique in order tocalculate water level, mean-depth velocities and horizontal and vertical velocities at differentdepth simultaneously. The results show the current circulation pattern features four eddies with twoclockwise and two anticlockwise induced by prevailing wind. Opposite wind field will lead toopposite current pattern with phase shifted by 180° The surface convergence zone is located in theupwind area and the surface divergence part in the downwind region, This results in drastic verticalmovement in the two zones and the return currents at the bottom with phase shifted by 180° fromthe surface current vectors. Thus the water level decreases significantly at the leeward side andincreases quickly at the windward part. Verification and calibration for the model were made basedon the water-level and current data observed during the 9711 Storm in Lake Taihu. The predictedresults are in satisfactory agreement with the observed data, which raises the possibility that thismodel can be used to decide the bottom current stress for sediment resuspension and also tosimulate sediment transportation. It can provide a fundamental tool to study the nutrient releasefrom bottom sediment in Lake Taihu.

关键词： numerical simulation three dimensional hydrodynamics lake taihu

Rate of strong consistency of quasi maximum likelihood estimate in generalized linear models

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Science china Mathematics 2004年第6期47卷 882-893页

作者： YUE Li & CHEN Xiru School of Mathematics and Statistics, Wuhan University, Wuhan 430072, china Graduate School, chinese academy of sciences. beijing 100039, china 1. School of Mathematics and Statistics Wuhan University 430072 Wuhan China 2. Graduate School Chinese Academy of Sciences 100039 Beijing China

Under the assumption that in the generalized linear model (GLM) the expectation of the response variable has a correct specification and some other smooth conditions, it is shown that with probability one the quasi-likelihood equation for the GLM has a solution when the sample size n is sufficiently large. The rate of this solution tending to the true value is determined. In an important special case, this rate is the same as specified in the LIL for iid partial sums and thus cannot be improved anymore.

关键词： quasi-likelihood function generalized linear models strong consistency

Olfactory receptor gene family evolution in stickleback and medaka fishes

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Science china(Life sciences. 2010年第2期53卷 257-266页

作者： CHEN Ming1,2,PENG ZuoGang1 & HE ShunPing1 1 Laboratory of Fish Phylogenetics and Biogeography,Institute of Hydrobiology,chinese academy of sciences.Wuhan 430072,china 2 Graduate University of chinese academy of sciences.beijing 100039,china 1. Laboratory of Fish Phylogenetics and Biogeography Institute of Hydrobiology Chinese Academy of Sciences Wuhan 430072 China2. Graduate University of Chinese Academy of Sciences Beijing 100039 China

Interaction of olfactory receptor (OR) genes with environmental odors is regarded as the first step of *** this study,OR genes of two fish,medaka (Oryzias latipes) and stickleback (Gasterosteus aculeatus),were identified and an evolutional analysis was *** selection pressure of different TM regions and complete coding region were *** TM regions (TM4,TM5 and TM6) were found to have higher average Ka/Ks values,which might be partly caused by positive selection as suggested by subsequent positive selection *** analysis showed that many PTSs overlap,or are adjacent to previously deduced binding sites in *** results support the hypothesis that binding sites of fish OR genes may evolved under positive selection.

关键词： olfactory receptor positive selection binding site

Variation properties of ionospheric eclipse factor and ionospheric influence factor

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Progress in Natural Science:Materials International 2005年第6期15卷 573-576页

作者： ZHAO Chunmei 1,2 *, YUAN Yunbin1, OU Jikun1 and CHEN Jinping3(1. Institute of Geodesy and Geophysics, chinese academy of sciences. Wuhan 430077, china 2. Graduate School of chinese academy of sciences. beijing 100039, china 3. Department of Precision Instrument and Mechanology, Tsinghua University, beijing 100084, china) Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China Graduate School of chinese academy of sciences Beijing 100039 China Department of Precision Instrument and Mechanology Tsinghua University Beijing 100084 China

The concepts and calculation methods of ionospheric eclipse factor (IEF) and ionospheric influence factor (IFF) are further illustrated. The temporal and spacial variation properties of IEF and IFF are studied, which shows that the properties are influenced by the geographic position and season. The possibility of improving the precision of using GPS data to determine ionospheric delay based on the above variation properties is also analysed.

关键词： GPS ionospheric eclipse factor ionospheric influence factor

Influence of the earth rotation on the interfacial wave solutions and wave-induced tangential stress in a two-layer fluid system

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Acta Oceanologica Sinica 2009年第2期28卷 115-120页

作者： SONG Jinbao LIU Yongjun Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China Key Laboratory of Ocean Circulation and Waves （KLOCAW） Chinese Academy of Sciences Qingdao 266071 China Graduate University of chinese academy of sciences Beijing 100039 China

Interfacial waves and wave-induced tangential stress are studied for geostrophic small amplitude waves of two-layer fluid with a top free surface and a fiat bottom. The solutions were deduced from the general form of linear fluid dynamic equations of two-layer fluid under the f-plane approximation, and wave-induced tangential stress were estimated based on the solutions obtained. As expected, the solutions derived from the present work include as special cases those obtained by Sun et al. （2004. Science in china, Ser. D, 47（12）： 1147-1154） for geostrophic small amplitude surface wave solutions and wave-induced tangential stress if the density of the upper layer is much smaller than that of the lower layer. The results show that the interface and the surface will oscillate synchronously, and the influence of the earth＇s rotation both on the surface wave solutions and the interfacial wave solutions should be considered.

关键词： two-layer fluid interfacial waves wave-induced tangential stress earth rotation

Formation of Ultrafine Metal Particles and Metal Oxide Precursor on Anodized Al by Electrolysis Deposition

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Journal of Materials Science & Technology 2000年第1期16卷 50-54页

作者： Lingchuan LI (Institute of Chemical Metallurgy, chinese academy of sciences. beijing 100080, china) Institute of Chemical Metallurgy Chinese Academy of Sciences Beijing 100080 China

Nickel was deposited by ac electrolysis deposition in the pores of the porous oxide film of Al produced by anodizing in phosphoric acid. Ultrafine rod-shaped Ni particles were formed in the pores. At the same time a film of Ni oxide precursor was developed on the surface of the porous oxide film. The Ni particles and the Ni oxide precursor were examined by SEM, TEM and X-ray diffraction. The thickness of the barrier layer of the porous oxide film was thin and it attributed to the formation of the metal particles, while the formation of the oxide precursor was associated with the surface pits which were developed in the pretreatment of Al.

关键词： Al Formation of Ultrafine Metal Particles and Metal Oxide Precursor on Anodized Al by Electrolysis Deposition

BIFURCATION OF THE NORTH EQUATORIAL CURRENT DERIVED FROM ALTIMETRY IN THE PACIFIC OCEAN

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Journal of Hydrodynamics 2006年第5期18卷 620-626页

作者： WANG Qing-ye HU Dun-xin Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China Graduate School of the chinese academy of sciences Beijing 100039 China

The gridded （1/3°＊1/3°） altimetry data from October 1992 through December 2004 were analyzed to study the seasonal and interannual variabilities of the bifurcation of the North Equatorial Current （NEC） at the surface in the western North Pacific Ocean. Calculations show that on annual average the bifurcation occurs at about 13.4°N at the surface. The geostrophic flow derived from Sea Surface Height （SSH） data shows that the southernmost latitude of the NEC bifurcation at the surface is about 12.9°N in June and the northernmost latitude is about 14.1°N in December. Correlation analyses between the bifurcation latitude and the Southern Oscillation Index （SOl） suggest that the bifurcation latitude is highly correlated with the E1 Nino/Southern Oscillation （ENSO） events. During the E1 Nino years the bifurcation of the NEC takes place at higher latitudes and vice versa.

关键词： bifurcation of the North Equatorial Current altimetry data Pacific Ocean North Equatorial Current (NEC),E1 Nino/Southern Oscillation (ENSO) events

Representation of microscale ocean wavenumber spectrum correct to the second order

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Science china Earth sciences 2005年第4期48卷 549-554页

作者： YUAN Yeli2 & HUA Feng1,2,3 1. Institute of Oceanology, chinese academy of sciences. Qingdao 266071, china 2. Key Laboratory of Marine Science and Numerical Modeling, State Oceanic Administration, Qingdao 266061, china 3. Graduate School of the chinese academy of sciences. beijing 100039, china 1. Key Laboratory of Marine Science and Numerical Modeling State Oceanic Administration 266061 Qingdao China 2. Institute of Oceanology Chinese Academy of Sciences 266071 Qingdao China 3. Graduate School of the chinese academy of sciences 100039 Beijing China

In this paper, the analytical representations of four wave source functions in high-frequency spectrum range are given on the basis of ocean wave theory and dimensional analysis, and the perturbation method is used to solve the governing equations of ocean wave high-frequency spectrum on the basis of the temporally stationary and locally homogeneous scale relations of microscale wave. The microscale ocean wavenumber spectrum correct to the second order has an explicit structure, its first order part represents the equilibrium between dif- ferent source functions, and its second order part represents the contribution of microscale wave propagation.

关键词： temporally stationary and locally homogeneous, source function in high-frequency spectrum range, microscale ocean wavenumber spectrum.