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Construction of habitat suitability models(HSMs) for benthic macroinvertebrate and their applications to instream environmental flows:A case study in Xiangxi River of Three Gorges Reservior region,china

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Progress in Natural Science:Materials International 2009年第3期19卷 359-367页

作者： Fengqing Li a,b, Qinghua Caia,*, Xiaocheng Fu a,b, Jiankang Liu a a State Key Laboratory of Freshwater Ecology and biotechnology, Institute of Hydrobiology, chinese academy of sciences, Wuhan 430072, china b graduate university of chinese academy of sciences, beijing 100039, china State Key Laboratory of Freshwater Ecology and biotechnology Institute of Hydrobiology Chinese Academy of Sciences Wuhan 430072 China graduate university of chinese academy of sciences Beijing 100039 China

based on a long-term ecological monitoring, the present study chose the most dominant benthic macroinvertebrate (baetis spp.) as tar- get organisms in Xiangxi River, built the habitat suitability models (HSMs) for water depth, current velocity and substrate, respectively, which is the first aquatic organisms model for habitat suitability in the chinese Mainland with a long-term consecutive in situ measurement. In order to protect the biointegrity and function of the river ecosystem, the theory system of instream environmental flow should be cat- egorized into three hierarchies, namely minimum required instream flow (hydrological level), minimum instream environmental flow (bio- species level), and optimum instream environmental flow (ecosystem level). These three hierarchies of instream environmental flow models were then constructed with the hydrological and weighted usable area (WUA) method. The results show that the minimum required instream flow of Xiangxi River calculated by the Tennant method (10% of the mean annual flow) was 0.615 m3 s 1; the minimum instream environmental flow accounted for 19.22% of the mean annual flow (namely 1.182 m3 s 1), which was the damaged river channel flow in the dry season; and 42.91% of the mean annual flow (namely 2.639 m3 s 1) should be viewed as the optimum instream environmental flow in order to protect the health of the river ecosystem, maintain the instream biodiversity, and reduce the impact of small hydropower stations nearby the Xiangxi River. We recommend that the hydrological and biological methods can help establish better instream environmental flow models and design best management practices for use in the small hydropower station project.

关键词： Habitat suitability model Weighted usable area Instream environmental flow benthic macroinvertebrate Xiangxi river Three Gorges reservoir

Late Neogene radiolarian absence event in the southern South china Sea and its paleoceanographic implication

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Progress in Natural Science:Materials International 2008年第3期18卷 281-287页

作者： Lili Zhanga,b, Muhong Chena, Lanlan Zhanga,b, Jun Lua, Rong Xianga a Key Laboratory of Marginal Sea Geology, South china Sea Institute of Oceanology, chinese academy of sciences, Guangzhou 510301, china b graduate university of chinese academy of sciences, beijing 100039, china Key Laboratory of Marginal Sea Geology South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou 510301 China graduate university of chinese academy of sciences Beijing 100039 China

Down-core variations of radiolarians at ODP Site 1143 in the southern South china Sea (SCS) are presented for the last 12 Myr. The fluctuations of radiolarian abundances since the Late Miocene can be divided into three stages: a high abundance stage at 12-5.96 Myr, a radiolarian absent stage at 5.96-3.30 Myr and a gradual increasing stage after 3.30 Myr. The three stages correspond to the forming and vicissitudes of the Western Pacific Warm Pool (WPWP) and the Eastern Asian Summer Monsoon (EASM). The radiolarian absence event (RAE) was also absent of diatom and occurred nearly simultaneously with the closures of the Panama Isthmus and the Indonesian seaway, which probably caused the reorganization of oceanic circulation systems. Accompanied this circulation reorganization was the weakening of the WPWP and the EASM, which probably led to a weakened upwelling in the southern SCS. In addition dissolved silica (Dsi) content in surface seawater might be very low during 5.96-3.30 Myr due to the ’’biogenic bloom" event, which consumed a large amount of Dsi in the surface seawater. All these factors together might lead to a great decrease of siliceous production in the southern SCS and consequently caused the RAE. Moreover, the dissolution of siliceous skeletons might also influence the abundance of radiolarians.

关键词： Southern South china Sea Late Neogene Radiolarian absence event

Equivalent lenses of supersonic seeker's outflow refractive index field obtained by simulation and experiment

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Equivalent lenses of supersonic seeker's outflow refractive ...

Spatial phase-shifting lateral shearing interferometer

2008 International Conference on Optical Instruments and Technology

作者： Qun WEI~(*a,b),Hongguang JIA~a,Ming XUAN~a a Changchun Institute of Optics,Fine Mechanics and Physics,chinese academy of sciences, Changchun 130033,china b graduate university of chinese academy of sciences,beijing 100039,china

In order to decrease the aerodynamic drag of supersonic image guide missile and design a non-spherical dome,the outflow field of the missile’s dome is simulated using *** on the simulated results,the accurate density field of the outflow field at all kinds of flight conditions is obtained,and then the refractive index field of the outflow field is gotten according to the Gladstone-Dale *** results show that the shock wave induces the heterogeneity of the refractive index field and the turbulent causes *** outflow field is divided into several zones which are taken as equivalent lenses for aberration analysis.

关键词： outflow field refractive index field dome density field FLUENT equivalent lens

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Spatial phase-shifting lateral shearing interferometer

Thermal difference analysis and athermalization Design of infrared optical system

2008 International Conference on Optical Instruments and Technology

作者： Xiaoxian GUO~(*a,b),Aijun ZENG~(a,c) and Huijie HUANG~a a Shanghai Institute of Optics and Fine Mechanics,chinese academy of sciences,Shanghai 201800, china b graduate university of chinese academy of sciences,beijing 100039,china c Shanghai Hengyi Optics & Fine Mechanics Co.,Ltd,Shanghai 201800,china

The phase-shifting lateral shearing interferometer is widely adopted for wavefront measurement with high *** real-time wavefront measurement,a spatial phase-shifting lateral shearing interferometer is *** interferometer includes a polarization lateral shearing module,a spatial phase-shifting module and an imaging *** polarization lateral shearing module consists of a Savart *** spatial phase-shifting module is component of a non-polarization beam splitter,a polarization beam splitter,two rectangular prisms and a half *** imaging module includes an imaging system and a *** measured wavefront is sheared by the polarization lateral shearing *** polarization directions of the two shearing beams are perpendicular to each *** two shearing beams are split into four groups of beams by the spatial phase-shifting module to form four interferograms in a 2×2 *** phase step of the four interferograms is 90 *** four interferograms are captured in a single frame image by the imaging *** experiments,a spherical wavefront with large radius of curvature was *** spatial phase-shifting interferograms of the wavefront was obtained *** usefulness of the interferometer is verified.

关键词： optical interferometry interferometer phase-shifting shearing Savart polariscope prism

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Thermal difference analysis and athermalization Design of in...

Twistor bundle theory and its application

2010亚洲光电子会议光学设计和检验分会场

作者： Ai Xing-qiao ab,Liu bo b,Zhang Xin b,Jia Hong-guang b a graduate university of chinese academy of sciences,beijing 100039,china b Changchun Institute of Optics,Fine Mechanics and Physics,Changchun 130033,china

When infrared optical system works in a large temperature range,the thermal effect of optical lens and optical tube will produce image plane shift and lead to imaging quality *** order to eliminate the thermal aberration,the athermalization design principles of infrared optical system were introduced,and some commonly used methods of thermal difference compensation were *** from single lens,the thermal difference caused by temperature changing was analyzed,and the relationship between temperature and focus shift was *** optical tube thermal expansion,a set of equations to estimate the thermal difference of lens group was ***,an infrared optical imaging system that can work under the temperature range of-40℃ to 60℃ was design according to athermal technique,in which a new mechanical passive temperature compensation was *** simulation,the athermalization design could make imaging plane shift the *** simulation results coincided with the theoretical formula,and the design had reference value in engineering.

关键词： infrared optical system thermal aberration athermalization passive mechanical athermalization

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Science china Mathematics 2004年第4期47卷 605-616页

作者： PENG Chia-Kuei & TANG ZizhouDepartment of Mathematics, graduate School of chinese academy of sciences, beijing 100039, china Department of Mathematical sciences, Tsinghua university, beijing 100084, china Department of Mathematics Graduate School of Chinese Academy of Sciences Beijing China Department of Mathematical sciences Tsinghua University Beijing China

Over an oriented even dimensional Riemannian manifold(M 2m ,ds2 ), in terms of the Levi-Civita connection form Ω and the canonical form Θ on the bundle of positive orthonormal frames, we give a detailed description of the twistor bundle Гm = SO(2m)/U(m)? J +(@#@ M,ds2 ) →M. The integrability on an almost complex structureJ compatible with the metric and the orientation, is shown to be equivalent to the fact that the corresponding cross section of the twistor bundle is holomorphic with respect toJ and the canonical almost complex structureJ 1 onJ +(M,ds2 ), by using moving frame theory. Moreover, for various metrics and a fixed orientation onM, a canonical bundle isomorphism is established. As a consequence, we generalize a celebrated theorem of Lebrun.

关键词： almost complex structure, integrability, twistor bundle.

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Evidence from isotopic geochemistry as an indicator of eutrophication of Meiliang bay in Lake Taihu, china

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Science china Earth sciences 2006年第Z1期49卷 62-71页

作者： LIN Lin, WU Jinglu & WANG Sumin Nanjing Institute of Geography & Limnology, chinese academy of sciences, Nanjing 210008, china graduate university of the chinese academy of sciences, beijing 100039, china Nanjing Institute of Geography & Limnology Chinese Academy of Sciences Nanjing China graduate university of the chinese academy of sciences Beijing China

In this paper, Lake Taihu, a large shallow freshwater lake in china, is chosen as an example of reconstruction of eutrophication through the comparison between stable isotopes from dissolved nutrients and plants and water column nutrient parameters and integration of multiple proxies in a sediment core from Meiliang bay including TN, TP, TOC, C/N, δ15N, δ13C, etc. Differences in aquatic plant species and trophic status between East Taihu bay and Meiliang bay are indicated by their variations in δ13C and δ15N of aquatic plants and δ15N of NH4+. A significant influence ofexternal nutrient inputs on Meiliang bay is reflected in temporal changes in δ 15N of NH4+ and hydro-environmental parameters. The synchronous change between δ13C and δ15N values of sedimented organic matter (OM) has been attributed to elevated primary production at the beginning of eutrophication between 1950 and 1990, then recent inverse correlation between them has been caused by the uptake of 15N-enriched inorganic nitrogen by phytoplankton grown under eutrophication and subsequent OM decomposition and denitrification in surface sediments, indicating that the lake has suffered from progressive eutrophication since 1990. based on the use of a combination of stable isotopes and elemental geochemistry, the eutrophication of Meiliang bay in Lake Taihu could be better traced. These transitions of the lake eutrophication respectively occurring in the 1950s and 1990s have been suggested as a reflection of growing impacts of human activities, which is coincident with the instrumental data.

关键词： stable carbon isotope of OM, stable nitrogen isotope, eutrophication, Lake Taihu.

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Models and methods for precise determination of ionospheric delay using GPS

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Progress in Natural Science:Materials International 2007年第2期17卷 187-196页

作者： YUAN Yunbin, HUO Xingliang and OU Jikun ( Institute of Geodesy and Geophysics, chinese academy of sciences, Wuhan 430077, china graduate university of chinese A-cademy of sciences, beijing 100039, china) Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China graduate university Chinese Academy of Sciences Beijing 100039 China

The basic principles and methods for precisely determining ionospheric delays in GPS observations are introduced and discussed. Various methods and models for fitting ionospheric delays based on GPS are compared and a... 详细信息

关键词： GPS ionospheric delay atmosphere modeling precise GPS positioning.

Applications of URANS on predicting unsteady turbulent separated flows

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Acta Mechanica Sinica 2009年第3期25卷 319-324页

作者： Jinglei Xu Huiyang Ma Department of Physics, graduate university of the chinese academy of sciences, 100049 beijing, china Department of Physics Graduate University of the Chinese Academy of Sciences Beijing China

Accurate prediction of unsteady separated turbulent flows remains one of the toughest tasks and a practi cal challenge for turbulence modeling. In this paper, a 2D flow past a circular cylinder at Reynolds number 3,900 is numerically investigated by using the technique of unsteady RANS （URANS）. Some typical linear and nonlinear eddy viscosity turbulence models （LEVM and NLEVM） and a quadratic explicit algebraic stress model （EASM） are evaluated. Numerical results have shown that a high-performance cubic NLEVM, such as CLS, are superior to the others in simulating turbulent separated flows with unsteady vortex shedding.

关键词： URANS Nonlinear eddy viscosity turbulencemodel ,Separated flows Circular cylinder

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