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Pattern Formation Around Interacting bodies in Rotating Fluids

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Journal of Thermal Science 2006年第2期15卷 132-134页

作者： Karl bHLER University of Applied Sciences badstrasse 24 D-77652 Offenburg Germany

The interaction of bodies like spheres and disks in rotating fluids leads to novel flow structures. The primary swirling flow in circumferential direction is superimposed by a secondary motion in the meridional plane. The flow is visualized by introducing ink through a hole in the center of the axes and distributed radially in the central plane between the interacting bodies. The flow structure depends on the shape of the bodies, their geometrical arrangement and the Reynolds number given by the rotational speed. The observed flow structures gave rise to further investigations with PIV-measurcments and numerical simulations.

关键词： Rotating fluids pattern formation recirculation zones interacting bodies flow visualization

Analytical evaluation of the plasma dispersion function for a Fermi-Dirac distribution

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Chinese Physics b 2012年第5期21卷 400-404页

作者： b.A.Mamedov Department of Physics Faculty of Arts and SciencesGaziosmanpa sa University

An efficient method for the analytic evaluation of the plasma dispersion function for the Fermi-Dirac distribution is *** new method has been developed using the binomial expansion theorem and the Gamma *** general formulas obtained for the plasma dispersion function are utilized for the evaluation of the response *** resulting series present better convergence *** acceleration techniques are combined to further improve the *** obtained results for the plasma dispersion function are in good agreement with the known numerical data.

关键词： Fermi Dirac distribution plasma dispersion function binomial coefficients incompletegamma functions

Exact Treatment of l≠0 States

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Chinese Physics Letters 2004年第9期21卷 1685-1688页

作者： b.Gonul DepartmentofEngineeringPhysics FacultyofEngineeringUniversityofGaziantep27310Gaziantep-Turkiye

Using the basic ingredient of supersymmetry, we present a general procedure for the treatment of quantum states having nonzero angular momenta.

关键词： Chpher(0) Nonzero Angle Countries (nations) QUANTUM STATES Angular momentum supersymmetry Exact

Spatial Variability of Soil Properties and Rice Yield Along Two Catenas in Southeast China

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Pedosphere 2008年第4期18卷 409-420页

作者： b. RTH b. LENNARTZ Institute for Land Use University of Rostock Justus-von-Liebig-Weg 6 18059 Rostock (Germany).

In the light of an increasing demand for staple food, especially rice, in southeast China, investigations on the specific site potential expressed as the relationship between soil and crop yield parameters gain increasing importance. Soil texture and several soil chemical parameters as well as plant properties such as crop height, biomass and grain yield were investigated along two terraced catenas with contrasting soil textures cropped with wet rice. We were aiming at identifying correlative relationships between soil and crop properties. Data were analyzed both statistically and geostatistically on the basis of semivariograms. Statistical analysis indicated a significant influence of the relief position on the spatial distribution of soil texture, total carbon and total nitrogen contents. Significant correlations were found for the catena located in a sandstone area (Catena A) between rice yield and silt as well as total nitrogen content. Corresponding relationships were not detectable for paddy fields that developed from Quaternary clays (Catena b). As suggested by the nugget to sill ratio, spatial variability of soil texture, total carbon and nitrogen was mainly controlled by intrinsic factors, which might be attributed to the erosional transport of fine soil constituents, indicating the importance of the relief position and slope in soil development even in landscapes that are terraced. The crop parameters exhibited short ranges of influence and about one third of their variability was unexplained. Comparable ranges of selected crop and soil parameters, found only for Catena A, are indicative of close spatial interactions between rice yield and soil features. Our findings show that especially in sandstone-dominated areas, a site-specific management can contribute to an environmentally safe rice production increase.

关键词： rice productivity semivariogram analysis soil properties spatial data

Separation of hematite from banded hematite jasper(bHJ) by magnetic coating

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Journal of Central South University 2015年第2期22卷 437-444页

作者： Subhashree Singh H.Sahoo S.S.Rath b.b.Palei b.Das CSIR-Institute of Minerals and Materials Technology

The separation of iron oxide from banded hematite jasper(bHJ) assaying 47.8% Fe, 25.6% Si O2 and 2.30%Al2O3 using selective magnetic coating was studied. Characterization studies of the low grade ore indicate that besides hematite and goethite,jasper, a microcrystalline form of quartzite, is the major impurity associated with this ore. beneficiation by conventional magnetic separation technique could yield a magnetic concentrate containing 60.8% Fe with 51% Fe recovery. In order to enhance the recovery of the iron oxide minerals, fine magnetite, colloidal magnetite and oleate colloidal magnetite were used as the coating material. When subjected to magnetic separation, the coated ore produces an iron concentrate containing 60.2% Fe with an enhanced recovery of56%. The AFM studies indicate that the coagulation of hematite particles with the oleate colloidal magnetite facilitates the higher recovery of iron particles from the low grade bHJ iron ore under appropriate conditions.

关键词： banded hematite jasper ore selective coating oleate colloidal magnetite magnetic separation atomic force microscopy

Theoretical and numerical investigation of HF elastic wave propagation in two-dimensional periodic beam lattices

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Acta Mechanica Sinica 2013年第6期29卷 783-798页

作者： b.Tie b.Y.Tian D.Aubry Laboratory MSSMat(UMR-CNRS 8579) Ecole Centrale ParisGrande Voie des Vignes92295 Chatenay-Malabry CedexFrance

The elastic wave propagation phenomena in two-dimensional periodic beam lattices are studied by using the bloch wave transform. The numerical modeling is applied to the hexagonal and the rectangular beam lattices, in which, both the in-plane （with respect to the lattice plane） and out-of-plane waves are considered. The dispersion relations are obtained by calculating the bloch eigenfrequencies and eigenmodes. The frequency bandgaps are observed and the influence of the elastic and geometric properties of the primitive cell on the bandgaps is studied. by analyzing the phase and the group velocities of the bloch wave modes, the anisotropic behaviors and the dispersive characteristics of the hexagonal beam lattice with respect to the wave prop- agation are highlighted in high frequency domains. One im- portant result presented herein is the comparison between the first bloch wave modes to the membrane and bend- ing/transverse shear wave modes of the classical equivalent homogenized orthotropic plate model of the hexagonal beam lattice. It is shown that, in low frequency ranges, the homog- enized plate model can correctly represent both the in-plane and out-of-plane dynamic behaviors of the beam lattice, its frequency validity domain can be precisely evaluated thanks to the bloch modal analysis. As another important and original result, we have highlighted the existence of the retro- propagating bloch wave modes with a negative group veloc- ity, and of the corresponding ＂retro-propagating＂ frequency bands.

关键词： Elastic wave propagation Periodic beam lattice bloch wave theory bandgaps Anisotropy Disper- sion relation

The gravity field and gravity data reduction across the continental area of Nigeria

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Geodesy and Geodynamics 2023年第3期14卷 304-320页

作者： Oluwatimilehin b.balogun Isaac b.Osazuwa Department of Geosciences Mountain Top UniversityPrayer CityOgun StateNigeria Department of Geophysics Federal UniversityOye-EkitiEkiti StateNigeria

This research presents the variation of the gravity field and associated gravity field components over the continental area of Nigeria to provide data for geoscience research,geodetic and engineering works,aerodynamic studies and deep crustal *** positions and elevations were observed at 58 of the 59 base stations of the Primary Gravity Network of Nigeria(PGNN),whose absolute gravity values had been accurately *** absolute gravity values were plotted against their respective positions to reveal the distribution pattern and strength of the gravity field within the study *** gravity values at each base station were generated using the Somigliana's *** free-air gravity and free-air anomaly gravity values were generated with respect to the World Geodetic System 1984(WGS84)ellipsoid using GPS-derived elevation ***,the perturbing potential,free-air gravity with respect to the geoid,and the indirect effects were *** average of the indirect effects was used to adjust the WGS84 gravity formula to produce a gravity formula that better approximates the geoid across the continental area of Nigeria,compatible with the heights measured relative to the geoid,which can serve as a reference for establishing a vertical height *** bouguer gravity and bouguer gravity anomalies across Nigeria revealed a“trans-southern gravity high strip”interpreted to be associated with mantle *** new major mega-lineaments related to mantle upwelling were mapped.A batholith province trending NWeSE was delineated,occurring from north central Nigeria to the north western region and containing closures of“bouguer gravity lows”interpreted as batholiths.A separate closure of“bouguer gravity low”was detected at Azare,north eastern Nigeria,which may be due to the presence of intrusive granitic *** is recommended that the mantle structure beneath“the trans-southern gravity high strip”,“delineated batholith province”and“isolat

关键词： Absolute gravity Continental Nigeria landmass Primary gravity network of Nigeria(PGNN) WGS84 ellipsoid Indirect effect Height datum

A comparison of food habits and prey preference of Amur tiger(Panthera tigris altaica)at three sites in the Russian Far East

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Integrative Zoology 2015年第4期10卷 354-364页

作者： Linda L.KERLEY Anna S.MUKHACHEVA Dina S.MATYUKHINA Elena S.ALMANOVA Galina P.SALKINA dale G.MIQUELLE Zoological Society of London Regent’s ParkLondonUK Sikhote-Alin biosphere Zapovednik TerneiPrimorskii KraiRussia FSbI“Land of Leopard ”VladivostokPrimorskii KraiRussia FSbI“United Lazovskii State Nature Zapovednik named after“Kaplanov”and Zov Tigra National Park ”Primorskii KraiRussia Wildlife Conservation Society BronxNew YorkUSA

Prey availability is one of the principal drivers of tiger distribution and ***,formulating effective conservation strategies requires a clear understanding of tiger *** used scat analysis in combination with data on the abundance of several prey species to estimate Amur tiger diet and preference at 3 sites in the Russian Far *** also examined the effect of pseudoreplication on estimates of tiger *** collected 770 scats across the 3 *** to previous studies,we found that tigers primarily preyed on medium to large ungulates,with wild boar,roe,sika and red deer collectively comprising 86.7%of total biomass consumed on *** to Jacobs’index,tigers preferred wild boar,and avoided sika *** in preference indices derived from these scat analyses compared to indices derived from kill data appear to be due to adjustments in biomass intake when sex–age of a killed individual is known:a component missing from scat ***(multiple samples collected from a single kill site)also skewed results derived from scat *** analysis still appears useful in providing insight into the diets of carnivores when the full spectrum of prey species needs to be identified,or when sample sizes from kill data are not *** sample sizes of kill data are large(as is now possible with GPS-collared animals),kill data adjusted by sex–age categories probably provides the most accurate estimates of prey biomass *** results provide further confirmation of the centrality of medium ungulates,in particular wild boar,to Amur tiger diet,and suggest that the protection of this group of species is critical to Amur tiger conservation.

关键词： Amur tiger diet Jacobs’index predation Russian Far East

Earth return path impedances of underground cable for three-layer earth

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第8期10卷 1191-1198页

作者： b.HEMMATIAN b.VAHIDI S.H.HOSSEINIAN Department of Electrical Engineering Amirkabir University of Technology

One of the factors that affect the parameters of an underground cable is earth return path *** developed a formula for the case of one-layer(homogenous) *** in practice the earth is composed of several *** this study we develop a new formula for earth return path impedance in the case of a three-layer *** check the accuracy of the obtained results,a comparison has been made with the finite element method(FEM).A comparison between the results of the Pollaczek formula and results of the obtained formula for a three-layer earth has been made,showing that the use of the Pollaczek formula instead of the actual formula can cause serious errors.

关键词： Underground cables Earth return path impedance Earth stratification Finite element method (FEM)