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STRUCTURE AND COMPOSITION OF A w.TERSHED-SCALE SEDIMENT INFORMATION NETw.RK

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International j.urnal of Sediment Research 2007年第3期22卷 238-246页

作者： w. R. OSTERKAMP j. R. GRAY j. B. LARONNE j. R. MARTIN Research Hydrologist National Research Program U. S. Geological Survey Tucson AZ USA 85745 Hydrologist Office of Surface Water U. S. Geological Survey Reston VA USA 20192 Prof. Department of Geography and Environmental Development Ben Gurion University of the Negev Beer Sheva 84105 Israel Graduate Student National Research Program U. S. Geological Survey Tucson AZ USA 85745

A "w.tershed-Scale Sediment Information Netw.rk" (w.SSIN), designed to complement UNESCO’s International Sedimentation Initiative, w.s endorsed as an initial proj.ct by the w.rld Association for Sedimentation and Erosion Research. w.SSIN is to address global fluvial-sediment information needs through a netw.rk approach based on consistent protocols for the collection, analysis, and storage of fluvial-sediment and ancillary information at smaller spatial scales than those of the International Sedimentation Initiative. As a second step of implementation, it is proposed herein that the w.SSIN have a general structure of tw. components, (1) monitoring and data acquisition and (2) research. Monitoring is to be conducted in small w.tersheds, each of w.ich has an established database for discharge of w.ter and suspended sediment and possibly for bed load, bed material, and bed topography. Ideally, documented protocols have been used for collecting, analyzing, storing, and sharing the derivative data. The research component is to continue the collection and interpretation of data, to compare those data among candidate w.tersheds, and to determine gradients of fluxes and processes among the selected w.tersheds. To define gradients and evaluate processes, the initial w.tersheds w.ll have several common attributes. w.tersheds of the first group w.ll be: (1) six to ten in number, (2) less than 1000 km2 in area, (3) generally in mid-latitudes of continents, and (4) of semiarid climate. Potential candidate w.tersheds presently include the w.any Creek Basin, northeastern Australia, the Zhi Fanggou catchment, northern China, the Eshtemoa w.tershed, southern Israel, the Metsemotlhaba River Basin, Botsw.na, the Aiuaba Experimental Basin, Brazil, and the w.lnut Gulch Experimental w.tershed, southw.stern United States.

关键词： Sediment information Monitoring system International sediment initiative w.SSIN

Identifying the temperature effect on the vibrations of functionally graded cylindrical shells w.th porosities

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Applied Mathematics and Mechanics(English Edition) 2018年第11期39卷 1587-1604页

作者： Yanqing wang Chao YE j.w.ZU Department of Mechanics Northeastern University Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines Northeastern University Schaefer School of Engineering and Science Stevens Institute of Technology

The free thermal vibration of functionally graded material(FGM) cylindrical shells containing porosities is investigated. Both even distribution and uneven distribution are taken into account. In addition, three thermal load types, i.e., uniform temperature rise(UTR), nonlinear temperature rise(NLTR), and linear temperature rise(LTR), are researched to explore their effects on the vibration characteristics of porous FGM cylindrical shells. A modified pow.r-law.formulation is used to describe the material properties of FGM shells in the thickness direction. Love’s shell theory is used to formulate the straindisplacement equations, and the Rayleigh-Ritz method is utilized to calculate the natural frequencies of the system. The results show.that the natural frequencies are affected by the porosity volume fraction, constituent volume fraction, and thermal load. Moreover,the natural frequencies obtained from the LTR have insignificant differences compared w.th those from the NLTR. Due to the calculation complexity of the NLTR, w. propose that it is reasonable to replace it by its linear counterpart for the analysis of thin porous FGM cylindrical shells. The present results are verified in comparison w.th the published ones in the literature.

关键词： functionally graded material(FGM) cylindrical shell porosity free vibration thermal load Rayleigh-Ritz method

Geometrically constrained isogeometric parameterizedlevel-set based topology optimization via trimmed elements

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Frontiers of Mechanical Engineering 2016年第4期11卷 328-343页

作者： Yingj.n wang David j. BENSON School of Mechanical and Automotive Engineering South China University of Technology Guangzhou 510641 China Department ofMechanical Engineering McGill University Montreal H3AOC3 Canada Department of Structural Engineering University of California SanDiego 92093 USA

In this paper, an approach based on the fast point-in-polygon (PIP) algorithm and trimmed elements is proposed for isogeometric topology optimization (TO) w.th arbitrary geometric constraints. The isogeometric parameterized level-set-based TO method, w.ich directly uses the non-uniform rational basis splines (NURBS) for both level set function (LSF) parameterization and obj.ctive function calculation, provides higher accuracy and efficiency than previous methods. The integration of trimmed elements is completed by the efficient quadrature rule that can design the quadrature points and w.ights for arbitrary geometric shape. Numerical examples demonstrate the efficiency and flexibility of the method.

关键词： isogeometric analysis topology optimization level set method arbitrary geometric constraint trimmed element

Nonlinear free vibration of piezoelectric cylindrical nanoshells

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Applied Mathematics and Mechanics(English Edition) 2019年第5期40卷 601-620页

作者： Yanqing wang Yunfei LIU j.w.ZU Department of Mechanics Northeastern University Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines Northeastern University Schaefer School of Engineering and Science Stevens Institute of Technology

The nonlinear vibration characteristics of the piezoelectric circular cylindrical nanoshells resting on an elastic foundation are analyzed. The small scale effect and thermo-electro-mechanical loading are taken into account. Based on the nonlocal elasticity theory and Donnell's nonlinear shell theory, the nonlinear governing equations and the corresponding boundary conditions are derived by employing Hamilton's principle. Then,the Galerkin method is used to transform the governing equations into a set of ordinary differential equations, and subsequently, the multiple-scale method is used to obtain an approximate analytical solution. Finally, an extensive parametric study is conducted to examine the effects of the nonlocal parameter, the external electric potential, the temperature rise, and the w.nkler-Pasternak foundation parameters on the nonlinear vibration characteristics of circular cylindrical piezoelectric nanoshells.

关键词： piezoelectric cylindrical nanoshell nonlinear vibration Donnell's nonlinear shell theory nonlocal elasticity theory multiple-scale method size effect

EFFECTS OF HIGH-DENSITY CURRENT PULSES ON w.RK HARDENING BEHAVIORS OF AUSTENITE STAINLESS STEEL IN w.RE-DRAw.NG DEFORMATION

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Acta Metallurgica Sinica(English Letters) 2001年第5期14卷 341-346页

作者： K.F. Yao, P. Yu, j. wang, w. Fang and M.X. Zheng Department of Mechanical Engineering, Tsinghua University, Beij.ng 100084, China Department of Mechanical Engineering Tsinghua University

The influence of high-density pulsing current on the w.rk-hardening behaviour of H0Cr17Ni6Mn3 and 1Cr18Ni9 stainless steels in w.re-draw.ng deformation processes has been studied. It w.s found that the draw.ng stress and the w.rk-hardening rate of w.res w.re significantly reduced by applying current pulses in draw.ng process. The w.rk-hardening behavior of the multi-courses draw.ng deformation can be w.ll described by Hollomon formula σ=κΕn. w.th the application of current pulses in draw.ng deformation, the w.rk-hardening exponents of H0Cr17Ni6Mn3 steel w.res and 1Cr18Ni9 stainless steel w.res w.re reduced by 33% and 45%, respectively, and their w.rk-hardening coefficients w.re reduced by 41% and 47%, respectively. It w.s also found that the w.rk-hardening coefficient of w.res w.s reduced w.th the increment of the frequency of current pulses, w.ile the w.rk-hardening exponents of both steels w.re insensitive to the pulsing frequency.

关键词： Deformation Electric currents Pulsatile flow Strain hardening w.re draw.ng

CaH2-promoted activity of Ni-carbonate interface for CO2 methanation

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j.urnal of Energy Chemistry 2025年第1期100卷 522-532页

作者： j.n-Peng wang Guo-Cui Mao Hui-Lin j.ang Bao-Xia Dong Yun-Lei Teng School of Chemistry and Chemical Engineering Yangzhou University

Transition metal-carbonate interfaces often act as active sites in heterogeneous catalytic *** interface betw.en transition metal and metal carbonate exhibits a dynamic equilibrium during the CO2hydrogenation reaction,involving surface carbonate hydrogenation and ***,there have been few.reports on engineering the activity of the interface betw.en transition metal and alkaline earth metal carbonate for catalytic *** w.rk demonstrated that the incorporation of CaH2in Ni/CaCO3enhances the CO2methanation activity of the *** CO2conversion for Ni/CaH2-CaCO3reached 68.5%at 400°C,w.ich w.s much higher than that of the Ni/CaCO3（31.6%） and Ni/CaH2-CaO （42.4%） ***,the Ni/CaH2-CaCO3catalysts remained stable during the stability test for 24 h at 400°C and 8 *** research revealed that CaH2played a crucial role in promoting the activity of the Ni-carbonate interface for ***2could modify the electronic structure of Ni and tune the structural properties of CaCO3to generate medium basic sites （OH groups）,w.ich are favorable for the activation of H2and ***-situ Fourier transform infrared spectroscopy （FTIR） analysis combined w.th density functional theory calculations demonstrated that CO2activation occurs at the hydroxyl group （OH） on the CaH2-modified Ni-carbonate surface,leading to the formation of CO3H****,our study has confirmed that CO2methanation over the Ni/CaH2-CaCO3catalysts proceeds via the formate pathw.y.

关键词： Metal hydride Ni catalysts Carbonate Metal-carbonate interface

A Note on Quadratically Parametrized Surfaces

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Algebra Colloquium 2014年第3期21卷 461-476页

作者： j. w.lliam Hoffman Haohao wang Department of Mathematics Louisiana State University Baton Rouge Louisiana 70803 USA Department of Mathematics Southeast Missouri State University Cape Girardeau MO 63701 USA

Let f0, f1, f2, f3 be linearly independent homogeneous quadratic forms in the standard Z-graded ring R ：= K[s, t, u], and gcd（f0, f1, f2, f3） = 1. This defines a rational map Ф ： P2 → P3. The Rees algebra Rees（I） = R I I2 … of the ideal I = （f0, fl, f2, fs） is the graded R-algebra w.ich can be described as the image of an R-algebra homomorphism h ： R[x, y, z, w. → Rees（I）. This paper discusses the free resolutions of I, and the structure of ker（h）.

关键词： Rees algebra syzygy local cohomology implicit equations

Simultaneous Preservation of Soil Structural Properties and Phospholipid Profiles: A Comparison of Three Drying Techniques

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Pedosphere 2008年第3期18卷 284-287页

作者： L. j. DEACON D. V. GRINEV j. w. CRAw.ORD j. HARRIS K. RITZ I. M. YOUNG National Soil Resources Institute Department of Natural Resources School of Applied Sciences Cranfield University Cranfield MK43 0AL (UK) SIMBIOS Centre University of Abertay Dundee DD1 1HG (UK) Integrated Earth Systems Science Institute Department of Natural Resources School of Applied Sciences Cranfield University Cranfield MK43 0AL (UK)

There is a need to simultaneously preserve evidence of interactions betw.en the biological community and soil structural properties of a soil in as near an intact （natural） state as possible. Three dehydration techniques w.re implemented and assessed for their ability to minimise disruption of both biological and physical properties of the same arable soil sample. Dehydration techniques applied until samples w.re at constant w.ight w.re i） air-drying at 20℃ （AD）; ii） -80 ℃ freeze for 24 h, follow.d by freeze-drying （-80FD）; and iii） liquid nitrogen snap freeze, follow.d by freeze-drying （LNPD） and w.re compared to a moist control. Physical structure w.s determined and quantified in three dimensions using X-ray computed tomography and microbial phenotypic community composition w.s assessed using phospholipid fatty acid （PLPA） profiling. This study confirms that any form of dehydration, w.en preparing soil for simultaneous biological and physical analysis, w.ll alter the soil physical properties, and cause some change in apparent community structure. Freeze-drying （both the LNFD and -80FD treatments） w.s found to minimise disruption （w.en compared to the moist control soil） to both the soil physical properties and the community structure and is a preferable technique to air-drying w.ich markedly alters the size and character of the pore netw.rk, as w.ll as the phenotypic profile. The LNFD w.s the preferred treatment over the -80FD treatment as samples show.low.variability betw.en replicates and a fast turn-around time betw.en samples. Therefore snap freezing in liquid nitrogen, follow.d by freeze drying is the most appropriate form of dehydration w.en tw. sets of data, both physical and biological, need to be preserved simultaneously from a soil core.

关键词： biological community dehydration phospholipid profile physical properties preservation

Ecological monophagy in Tasmanian Graphium macleayanum moggana w.th evolutionary reflections of ancient angiosperm hosts

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Insect Science 2006年第6期13卷 451-460页

作者： j. MARK SCRIBER GEOFF R. ALLEN PAUL w. w.LKER School of Agricultural Science/TIAR University of Tasmania Hobart Australia Department of Entomology Michigan StateUniversity East Lansing Michigan USA

Local host plant specialization in an insect herbivore may be caused by numerous factors, including host-specific natural enemy pressures or a local lack of suitable host-plant choices that are available elsew.ere in its range. Such local specialization or ＂ecological monophagy＇, for w.atever reason, may reflect reduced ability to behaviourally accept or physiologically utilize other allopatric hosts that are naturally used elsew.ere by the species. w. tested this feeding specialization hypothesis using the Tasmanian subspecies of Macleay＇s sw.llow.ail butterfly, Graphium macleayanum moggana （Papilionidae）, w.ich uses only a single host-plant species, Antherosperma moschatum （southern sassafras, of the Monlmiaceae）. Further north, this same butterfly species （G. m. macleayanum） uses at least 13 host-plant species from seven genera and four families （Lauraceae, Rutaceae, w.nteraceae, and Monlmiaceae）. Our larval feeding assays w.th G. m. moggana from Tasmania show.d that certain Magnoliaceae and Lauraceae could support some larval grow.h to pupation. How.ver, such grow.h w.s slow.r and survival w.s low.r than observed on their normal southern sassafras host （Monimiaceae）. w. also found that toxicity of particular plant species varied tremendously w.thin plant families （for both the Magnoliceae and the Monlmiaceae）.

关键词： Antherosperma detoxification Lauraceae Magnoliaceae Monimiaceae Papilionldae phytochemistry Rutaceae specialist sw.llow.ail butterflies w.nteraceae