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Some　Aspects　of　the　Characteristics　of　Monsoon　Disturbances　Using　a　Combined　Barotropic－Baroclinic　Model

Advances in Atmospheric Sciences 1995年第4期12卷 487-506页

作者： n. R. Parija S. k. Dash Centre for Atmospheric Sciences Indian Institute of Technology New Delhi India

A standing Rossby wave of wavelength 30°longitude with a finite amplitude along the meridional direction is superimposed on the zonal mean component of the monsoon flow and the stability of such a flow is examined by a quasi-geostrophic *** well as by a quasi-geostrophic combined barotropic and baroclinic model on a beta plane centered at 18°n latitude. It is found that the growth of synoptic scale disturbance increases with the amplitude of the meridional wind. The barotropic stability analysis at 700 hPa pressure level shows that there is a critical value (Umaz=11 m/s) of the maximum mean zonal wind below which the computed disturbance moves to the west due to the wave-wave superposition. For maximum mean zonal wind greater that 11m /s, the westerly wind dominates and the disturbance moves to the east. In another analysis the stability of the zonally asymmetric basic now is studied with a combined barotropic-barotropic model where cumulus heating is included. The growth rate, intensity, horizontal scale and the westward velocity of computed disturbances reasonably agree with those of observed monsoon disturbances. The fastest growing mode has a horizontal wavelength of 2000 k.s and the e-folding time is about 3 days,when the meridional amplitude of the Rossby wave is 4m/ s at 700 hPa pressure level. When cumulus heating is included in the analysis the intensity of geopotential perturbation at 700 hPa disturbance is -304 m2 / s2. Energy calculations show that the k.netic energy of the mean zonal flow is the main source of energy for the perturbation to *** is also t'ound that the contribution of the k.netic energy of the basic Rossby wave to the growth of perturbation is more in comparison to the available potential energy.

关键词： Monsoon disturbance Rossby wave Combined barotropic-baroclinic stability

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Solvent effects on hydrogen bonding between primary alcohols and esters

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第11期7卷 1928-1931页

作者： DHARMALInGAM k. RAMACHAnDRAn k. SIVAGURUnATHAn P. Department of Physics Annamalai University Annamalai Nagar 608002 Tamilnadu India

The interaction by hydrogen bond formation of some primary alcohols （ l-heptanol, l-octanol and l-decanol） with esters （methyl methacrylate, ethyl methacrylate and butyl methacrylate） was investigated in non-polar solvents viz., n-heptane, CC14 and benzene by means of FTIR spectroscopy. Formation constants and free energy changes of complex formation were determined. The dependence of the equilibrium constants and free energy changes of complex formation on the alk.l chain length of both the alcohols and esters are discussed. The solvent interaction between the solute and solvent. effect on the hydrogen bond formation is discussed in terms of specific

关键词： FTIR spectroscopy Primary alcohols Esters Hydrogen bonding Solvent effect

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Convective heat transfer from two rotating circular cylinders in tandem arrangement by using lattice Boltzmann method

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Applied Mathematics and Mechanics(English Edition) 2012年第4期33卷 427-444页

作者： H. nEMATI M. FARHADI k. SEDIGHI M. M. PIROUZ n. n. ABATARI Faculty of Mechanical Engineering Babol Noshirvani University of Technology

The numerical investigation of the two-dimensional laminar flow past two ro- tating circular cylinders in the tandem arrangement is conducted by the lattice Boltzmann method. The numerical strategy is used for dealing with curved and moving boundaries of the second-order accuracy for velocity and temperature fields. The effects of various rotational speed ratios and gap spacing are studied with the Reynolds number of 100 and the Prandtl number of 0.71. A varied range of rotational speed ratios are investigated for four different gap spacing, i.e., 3.0, 1.5, 0.7, and 0.2. The results show that, for the first cylinder, the lift and drag coefficients for large gap spacing are similar to those for a single cylinder; for the second cylinder, the lift coefficient descends with the increase in the angular velocity for all gap spacing, while the drag coefficient ascends except for the gap spacing of 3.0. The results of the averaged periodic nusselt number on the surface of the cylinders show that, for small distances between the cylinders and low angular velocities, conduction is a dominant mechanism of heat transfer, but for large distances and high angular velocities, convection is the main mechanism of heat transfer.

关键词： lattice Boltzmann method rotating circular cylinder laminar flow curvedand moving boundary

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Transfer of natural Micro Structures to Bionic Lightweight Design Proposals

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Journal of Bionic Engineering 2013年第4期10卷 469-478页

作者： M. Maier D. Siegel k.-D. Thoben n. niebuhr C. Hamm Alfred Wegener Institute for Polar and Marine Research Am Handelshafen 12 27570 Bremerhaven Germany Institute for Marine Resources GmbH Bussestr. 27 27570 Bremerhaven Germany University of Bremen Hoehschulring 20 28359 Bremen Germany

The abstraction of complex biological lightweight structure features into a producible technical component is a funda- mental step within the transfer of design principles from nature to technical lightweight solutions. A major obstacle for the transfer of natural lightweight structures to technical solutions is their peculiar geometry. Since natural lightweight structures possess irregularities and often have extremely complex forms due to elaborate growth processes, it is usually necessary to simplify their design principles. This step of simplification/abstraction has been used in different biomimetic methods, but so far, it has an arbitrary component, i.e. it crucially depends on the competence of the person who executes the abstraction. This paper describes a new method for abstraction and specialization of natural micro structures for technical lightweight compo- nents. The new method generates stable lightweight design principles by using topology optimization within a design space of preselected biological archetypes such as diatoms or radiolarian. The resulting solutions are adapted to the technical load cases and production processes, can be created in a large variety, and may be further optimized e.g. by using parametric optimization.

关键词： biomimetic finite elements design space design principle topology optimization parametric optimization dia- toms radiolarian

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Spectral Response and Photoelectrochemical Properties of Cd1-xZnxSe Films

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Chinese Physics Letters 2010年第5期27卷 200-203页

作者： n. J. Suthan k.ssinger G. Ghana k.mar k. Perumal J. Suthagar Department of Physics Loyola Institute of Technology and Sciences Loyola Nager Thovalai India Specialized Graduate School of Hydrogen and Fuel Cell Engineering Chonbuk National University Jeonju 561-756 Republic of Korea Department of Physics SRMV College of Arts and Science Coimbatore India Department of Physics Karunya University Coimbatore India

Cd1-xZnxSe films with different zinc contents are deposited by an electron beam evaporation technique onto glass substrates for applications in solid-state photovoltalc devices. The structural, optical and photoelectrochemical （PEC） properties of Cd1-xZnxSe films are studied. The host material Cd1-xZnxSe is prepared by the physical vapor deposition method of electron beam evaporation technique （PVD： EBE） under a pressure of 1 × 10^-5 mbar. The x-ray diffractogram indicates that these alloy films are polycrystalline in nature, hexagonal structure with strong preferential orientation of the crystallites along （002） direction. The optical properties shows that the band gap Eg varies from 2.08 to 2.84eV as zinc content varies from 0.2 to 0.8. A PEC cell of the configuration n-Cd1-xZnxSe/na2S-S-naOH is fabricated and the dynamic current-voltage characteristics in the dark.atmosphere have been examined at room temperature. It has been found that both Voc and Iac decrease with the photoelectrode composition x. Efficiency η and fill factor （FF） also show similar variations. The material properties would be altered and excellently controlled by controlling the system composition x.

关键词： SPECTRAL sensitivity PHOTOELECTROCHEMISTRY ZInC selenide THIn films -- Optical properties EVAPORATIOn (Chemistry) SOLID state electronics PHOTOVOLTAIC cells MOLECULAR structure PHYSICAL vapor deposition

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Estimation of water requirement per unit carbon fixed by Eucalyptus camaldulensis in semi-arid land of Western Australia

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Science China Earth Sciences 2002年第z1期45卷 142-147页

作者： T. k.jima Y. Tanak. S. k.toh k. Taha.a.n. Tak.hashi k. Yamada Department of Applied Chemistry Fac. of Eng. Seikei University Tokyo 180-8633 Japan Japan Science and Technology Corporation Tokyo 110-0015 Japan Deptartment of Fine Materials Engineering Shinshu University Nagano Pre. 386-8567 Japan

Afforestation in arid land is a promising method for carbon fixation, but the effective utili- zation of water is highly important and required. Thus, the evaluation of the amount of water per unit carbon fixed with the tree growth is required to minimize the amount of water supplied to the plants. In this research, a tree is regarded as a carbon fixation reactor with inflows of water and nutrients from roots, and CO_2 as the carbon source from leaves with outflow of water vapor from leaves and accumulation in the tree itself. In the process of photosynthesis and respiration nutri- tional elements are dissolved in water flow in trees. They do not flow out by these reactions, but are accumulated in trees. Thus, we have treated the behaviour of nutrients as a mark.r to evaluate the water/carbon ratio. Assuming that nutrient concentration is constant in sap, and the differences in the ratios of nutrient to carbon in living trees and dead (i.e. litter fall, etc.) are neglected, the ratio of the used water to fixed carbon is given as the ratio of nutrient to carbon in the tree body divided by the ratio of nutrient to water in sap. However, some nutrients are translocated and concentrated within the tree and some may be discarded through litter fall. Thus it is important to examine which nutrient element is the most suitable as the tracer. In this paper, the results of the above method applied to Eucalyptus camaldulensis in semi- arid land of Western Australia are shown. The value of water requirement per unit carbon fixation determined from potassium balance is between 421 k.-H_2O/k.-C for mature trees and 285 k.-H_2O/k.-C for young trees, while the values from calcium balance are much larger than these. The cause of the discrepancy between these values is discussed based on the measured element concentrations in sap and trees and the plant physiology. Finally, the actual average value through the life of a tree is suggested to fall between the two values.

关键词： carbon fixation, unit water requirement, arid land, Western Australia, Eucalyptus camaldulensis,

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On the Complementarity of Absorption and MCD Spectroscopy

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Journal of Rare Earths 1998年第3期16卷 45-51页

作者： Binnemans, k. Gorller-Walrand, C Univ of Leaven Heverlee Belgium

The use of magnetic circular dichroism(MCD) spectroscopy for probing the 4f n configuration of trivalent lanthanide ions is explored. The technique is compared with optical absorption spectroscopy. MCD is valuable for the detection of degenerate crystal field levels in uniaxial crystals and for observing transitions not resolved in the absorption sepctrum, for the study of the site symmetry and for check.ng the reliability of crystal field and intensity parameters. On the other hand, selection of the samples has to be done more carefully than for absorption spectroscopy, because an MCD spectrum can only be recorded in an isotropic direction.

关键词： Rare earths Lanthanides Magnetic circular dichroism Zeeman effect Optical absorption

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Microstructure and corrosion behavior of Mg-Sn-Ca alloys after extrusion

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中国有色金属学会会刊：英文版 2009年第1期19卷 40-44页

作者： T. ABU LEIL n. HORT W. DIETZEL C. BLAW ERT Y. HUAnG k. U. k.InER k. P. RAO Gk.S Forschungszentrum Geesthacht GmbH Max-Planck.Strasse 1 Geesthacht 21502 Germany City University of Hong k.ng 83 Tat Chee Avenue Kowloon Hong Kong

Mg-Sn-Ca alloys promise a reasonable corrosion resistance in combination with good creep resistance, lik.ly due to the presence of Ca2-xMgxSn and other phases. The selected alloys with 3% Sn and Ca in the range of 1%-2% have been extruded in order to achieve more homogeneous microstructure compared with the as-cast alloys. Optical microscopy(OM) and X-ray diffraction(XRD) techniques were used to study the microstructure and phases of these alloys. The corrosion behavior of these alloys was investigated by means of salt spray test and potentio-dynamic measurements. The results obtained on the alloys Mg-3Sn (T3), Mg-3Sn-1Ca (TX31), and Mg-3Sn-2Ca (TX32) indicate the presence of the same phases in as-cast and after extrusion, namely Mg2Sn, Ca2-xMgxSn, and Ca2-xMgxSn/Mg2Ca, respectively. However, due to the occurrence of extensive recrystallization in the extrusion process, the grain size has significantly reduced after extrusion. The reduction leads to the improvement of the corrosion resistance after extrusion which is then comparable with the commercial alloy AZ91D.

关键词： Mg-Sn-Ca合金腐蚀镁合金金属腐蚀

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Zn Doping Effect on Magnetic Properties of Znx Cdl-xCr2S4 Systems by High-Temperature Series Expansions

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Chinese Physics Letters 2007年第7期24卷 2077-2080页

作者： M. Hamedoun R. Masrour k. Bouslyk.ane A. Hourmatallah n. Benzak.ur A. Filali Laboratoire de Physique du Solide Universite Sidi Mohammed Ben Abdellah Facult~ des sciences Dhar Mahraz BP 1796 Fes Morocco Equipe de Physique du Solide Ecole Normale Superieure BP 5206 Bensouda Fes Morocco

The effect of Zn doping on the magnetic properties of CdCr2S4 systems is studied by mean field theory and high-temperature series expansion （HTSE）. The nearest neighbouring and the next-neighbouring super-exchange interactions Jl（x） and J2（x） are evaluated for the spinel system Zn, Cd1-xCr2S4 in the range 0 〈 x 〈 1. The intra-planar and the inter-planar interactions are deduced. The HTSE combined with the Padd approximant method （PA） is applied to the spinel system ZnxCdl-,Cr2S4. The magnetic phase diagram, i.e. Tc versus dilution x, is obtained. The critical exponents associated with the magnetic susceptibility 7 and the correlation length u are deduced. The obtained theoretical results are in agreement with the experimental data obtained by magnetic measurements.

关键词： Magnetic Properties High-Temperature HTSE

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Delamination Testing of AlSi10Mg Sandwich Structures with Pyramidal Lattice Truss Core made by Laser Powder Bed Fusion

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Chinese Journal of Mechanical Engineering 2021年第6期34卷 51-62页

作者： M.nuño J.Bühring M.n.Rao k.-U.Schröder Institute of Structural Mechanics and Lightweight Design RWTH Aachen UniversityWüllnerstraβe 752072 AachenGermany

Sandwich structures possess a high bending stiffness compared to monolithic structures with a similar *** mak.s them very suitable for lightweight applications,where high stiffness to weight ratios are *** common manufacturing methods of sandwich structures involve adhesive bonding of the core material with the ***,adhesive bonding is prone to delamination,a failure mode that is often difficult to *** paper presents the results of delamination testing of fully additive manufactured(AM)AlSi10Mg sandwich structures with pyramidal lattice truss core using Laser Powder Bed Fusion(LPBF).The faces and struts are 0.5 mm thick.while the core is 2 mm *** inclination of the struts is 45°.To characterise the bonding strength,climbing drum peel tests and out-of-plane tensile tests are *** formulas are derived to predict the expected failure loads and *** analytics and tests are supported by finite element(FE)*** the analytic approach,design guidelines to avoid delamination in AM sandwich structures are *** study presents a critical face sheet thick.ess to strut diameter ratio for which the structure can *** ratio is mainly influenced by the inclination of the *** peel tests resulted in face yielding,which can also be inferred from the analytics and *** out-of-plane tensile tests didn’t damage the structure.

关键词： Additive Manufacturing Sandwich Structures Pyramidal Lattice Core

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