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DNS in evolution of vorticity and sign relationship in wake transition of a circular cylinder:(pure)mode A

Acta Mechanica Sinica 2019年第6期35卷 1131-1149页

作者： l.M.lin Z.r.Tan Key laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Navigation Wuhan University of TechnologyWuhan 430063China Hubei Key laboratory of Inland Shipping Technology Wuhan University of TechnologyWuhan 430063China

In the present paper,the spatio-temporal evolution of vorticity in the first wake instability,i.e.,(pure)mode A,is investigated in order to understand the wake vortex dynamics and sign relationships among vorticity *** numerical simulation(DNS)for the flow past a circular cylinder is performed,typically at a reynolds number of 200,in the three-dimensional(3-D)wake *** to characteristics of time histories of fluid forces,three different stages are identified as the computational transition,the initial stage and fully developed *** the second initial stage,the original two-dimensional spanwise vortices become obviously three-dimensional associated with the streamwise or vertical vorticity intensified up to about *** a matter of fact,these additional vorticities,caused by the intrinsic 3-D instability,are already generated firstly on cylinder surfaces early in the computational transition,indicating that the three-dimensionality appeared early near the *** evolution of additional components of vorticity with features the same as mode A shows that(pure)mode A can be already formed in the late computational *** careful analysis of the vorticity field on the front surface,in the shear layers and near wake at typical times,two sign laws are *** illustrate intrinsic relationships among three vorticity components,irrelevant to the wavelength or Fourier mode and reynolds number in(pure)mode *** importantly,the origin of streamwise vortices is found and explained by a new physical mechanism based on the theory of vortex-induced *** a result,the whole process of formation and shedding vortices with these vorticities is firstly and completely *** characteristics are presented in detail.

关键词： Wake transition Circular cylinder Vorticity Mode A Sign law

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Metal separations of interest to the Chinese metallurgical industry

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Journal of rare Earths 2010年第S1期28卷 22-29页

作者： S.r.Izatt N.E.Izatt r.l.Bruening IBC Advanced Technologies Inc.856 E.Utah Valley DriveAmerican ForkUT 84003U.S.A.

IBC Advanced Technologies’ Molecular recognition Technology(MrT) Superlig products selectively and rapidly bind with target species enabling their selective removal from *** MrT process can produce a high purity separation product of maximum added value at a competitive *** products have high selectivity for many target species which can include metal ions,anions,and neutral *** operation,the Superlig product is first placed in a packed column.A solution containing a mixture of the target species and other chemical species is then passed through the *** target species is removed selectively by the Superlig product,the column is washed to remove residual feed solution,and the target species is recovered by a minimal quantity of *** result is a pure and concentrated species that can be kept for its value or disposed of *** process is environmentally and ecologically friendly with no organic solvents being *** paper provides a review of some examples of applications of MrT to separations of interest to the Chinese metallurgical *** are several applications of MrT,including Pd separations from Pt metal refinery streams and low-grade spent catalyst wastes,rh recovery from spent auto catalyst and other feeds,re removal from selected impurity ions,Cd removal from Co electrolyte,Bi removal from Cu electrolyte,In and Ge separations from difficult matrices,and removal of bivalent first transition series and other metal ions from acid mine drainage(Berkeley Pit,Montana).Finally,the potential application of MrT to separations involving the recovery of rare earth metals and li from low-level waste solutions and end-of-life products is discussed.

关键词： selective and environmentally friendly metal separations molecular recognition technology Superlig platinum group metals minor metals transition series metals rhenium cadmium indium germanium bismuth rare earth metals lithium

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laser induced photo-detachment of O2 in DC discharge

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Plasma Science and Technology 2018年第7期20卷 98-105页

作者： j r legorreta j l patiNo f b yousif Centro de Investigacion en Ciencias Universidad Autonoma del Estado de Morelos.Av.UniversidadNo.1001 Col.Chamilpa Cuemavaca MorelosMexico

Determination of the negative ion number density of O2 and O in a DC discharge of oxygen plasma was made employing langmuir probe in conjunction with eclipse laser photo- detachment technique. The temporal evolution of the extra electrons resulting from the photo- detachment of O2- and O- were used to evaluate the negative ion number density. The ratio of O2 number density to O varied from 0.03 to 0.22. Number density of both O~ and O increased with increasing power and decreased as the pressure was increased. Electron number density was evaluated from the electron energy distribution function （EEDF） using the I-V recorded characteristic curves. Electron temperature between 2 and 2.7 eV were obtained. Influence of the 02（al△g） metastable state is discussed.

关键词： electronegative plasma electron temperature langmuir probe negative ion number density

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Spectral indices derived,non-parametric Decision Tree Classification approach to lithological mapping in the lake Magadi area,Kenya

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International Journal of Digital Earth 2018年第10期11卷 1020-1038页

作者： Gayantha r.l.Kodikara Tsehaie Woldai Department of Oceanography and Marine Geology Faculty of Fisheries&Marine Science and TechnologyUniversity of RuhunaSri Lanka School of Geosciences University of the WitwatersrandJohannesburgSouth Africa

Here,we demonstrate the application of Decision Tree Classification(DTC)method for lithological mapping from multi-spectral satellite *** area of investigation is the lake Magadi in the East African rift Valley in *** work involves the collection of rock and soil samples in the field,their analyses using reflectance and emittance spectroscopy,and the processing and interpretation of Advanced Spaceborne Thermal Emission and reflection radiometer data through the DTC *** latter method is strictly non-parametric,flexible and simple which does not require assumptions regarding the distributions of the input *** has been successfully used in a wide range of classification *** DTC method successfully mapped the chert and trachyte series rocks,including clay minerals and evaporites of the area with higher overall accuracy(86%).Higher classification accuracies of the developed decision tree suggest its ability to adapt to noise and nonlinear relations often observed on the surface materials in space-borne spectral image data without making assumptions on the distribution of input ***,the present work found the DTC method useful in mapping lithological variations in the vast rugged terrain accurately,which are inherently equipped with different sources of noises even when subjected to considerable radiance and atmospheric correction.

关键词： Decision Tree Classification ASTEr data lithological mapping lake Magadi

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From granulite fluids to quartz-carbonate megashear zones:The gold rush

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Geoscience Frontiers 2014年第5期5卷 747-758页

作者： Bin Fu Jacques l.r.Touret research School of Earth Sciences The Australian National University Institut de Mineralogie.de Physique des Materiaux et de Cosmochimie(IMPMC) Sorbonne Universites UPMC Univ Paris 06.UMR CNRS 7590 Museum National d'Histoire Naturelle IRD UMR 206.4 Place Jussieu.F-75005 Paris.France

At peak granulite-facies metamorphic conditions, lower continental crust is arguably fluxed by large amounts of two key low water activity fluids：（i） high-density CO2 and/or （ii） concentrated saline so- lutions. These fluids are either internally-derived, generated by mineral reactions or dehydration melting or, notably for CO2, externally-derived, issued from the underlying mantle. Postmetamorphic evolution results in complete disappearance of these fluids, except for minute remnants preserved in minerals as fluid inclusions. Two major processes are involved：（i） at peak conditions, granitoid magmas form, migrate upward, and crystallize as shallow intrusions in the upper crust （mineralized porphyry types or reduced intrusions）; （ii） during the rapid decompression which almost systematically follows a period of post-peak isobaric cooling, especially for ultrahigh-temperature granulites （anticlockwise P-T paths）, quartz-carbonate megashear zones are formed by repeated periods of seismic activity. Seismic activity may continue until all free fluids have disappeared, resulting in the ultramylonites and pseudotachylites that are found in many granulite domes. A great majority of vein-type Au deposits worldwide occur in the above-mentioned settings or nearby. We suggest that the Au has been scavenged by the granulite fluids, then redistributed and concentrated during the formation of veins and related phenomena.

关键词： Granulite CO2 BrinesMegashear zonesAu mineralization

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Equilibrium, thermodynamic, and kinetic of Cr(VI) adsorption using a modified and unmodified bentonite clay

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International Journal of Mining Science and Technology 2014年第4期24卷 525-535页

作者： D.J.l. Guerra I. Mello l.r. Freitas r. resende r.A.r. Silva Department of Mineral resources University Federal of Mato Grosso DRM-UFMT Mato Grosso 78060900 Brazil

The capacities of natural and modified Brazilian bentonite samples as adsorbents to remove hexavalent metal chromium were investigated under several conditions in batch and column methods. The raw material, Ca-bentonite, was modified by anchorament of 3-aminopropyltrietoxisilane （APS） and 3,2- aminoethylaminopropyltrimetoxisilane （AEAPS） in the surface of bentonite sample： This type of new occurrence of bentonite is suitable as a raw material for adsorption process. Adsorption behavior of three bentonite types was strongly depending on pH of adsorbate solution, contact time adsorbent/adsorbate, and initial concentration of Cr（VI）. The results were confirmed by column method and reveals that the adsorption process of materials accorded by the redlich-Peterson, Sips, Dubinin-radushkevich, and tang- muir isotherm models. The exothermic entbalpic values reflected a favorable energetic process for chro- mium ions anchored in the material surfaces. The negative Gibbs free energy results supported the spontaneity of three adsorption reactions with Cr（VI） ions.

关键词： Bentonite Organo-bentonite Chromium Equilibrium Kinetic Adsorption

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Jahn-Teller Distortion of the Zinc Vacancy in ZnGeP2

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Chinese Physics letters 2008年第3期25卷 1075-1078页

作者：姜晓庶 Walter r. l. lambrecht Physics Department Shanxi University Taiyuan Shanxi 030006 Physics Department Case Western Reserve University Cleveland Ohio 44106 USA

A symmetry analysis and a simple dangling bond model are presented for the VZn^- in ZnGeP2, identifying a possible Jahn-Teller distortion mechanism which could naturally explain the localization of the defect wavefunc... 详细信息

关键词： NUClEAr DOUBlE-rESONANCE

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Indirect calorimetry to estimate energy requirements for growing and finishing Nellore bulls

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Journal of Integrative Agriculture 2017年第1期16卷 151-161页

作者： S l Posada-Ochoa r r Noguera N M rodriguez A l Costa r reis research Group in Agricultural Science-GrICA Faculty of Agricultural Sciences Universidad de Antioquia Medellin AA 1226 Colombia Animal Science Department of Veterinary School Universidade Federal de Minas Gerais Belo Horizonte CEP 31270-901 Brazil

Determination of nutritional requirements is the basis for diet formulation. The objectives of this study were to determine the net energy requirements for maintenance （NEro） and weight gain （NEg） in Nellore bulls during the growing and finishing phases, and to estimate efficiency of metabolizable energy （ME） utilization for maintenance and gain （km, kg）. Five Nellore bulls were housed in individual pens at the Universidade Federal de Minas Gerais （Belo Horizonte, Brazil） and evaluated over four experimental periods at 210, 315,378 and 454 kg shrunk body weight （SBW）, approximately. During each period, heat production （HP） was quantified by open circuit indirect calorimetry for three feeding levels： ad libitum, restricted and fasting. The NEm requirement was determined by linear regression between the log of HP andthe ME intake （MEI） for the ad libitum and restricted levels. This requirement was also determined by quantifying fasting heat production （FHP）. The NEQ requirement was calculated by the difference between MEI and HP during ad libitum feeding. The k and kg were calculated by the relationship between net energy （NE） and ME requirements for maintenance and weight gain （MEm, MEp）, respectively. The NEm requirements per kg of metabolic empty body weight （EBW0.75） fluctuated between 348 and 517 kJ d-1, showing a decreasing trend with age, and were higher than the values reported in the literature. The NEg requirements ranged between 48.3 and 164 kJ kg-1 EBW0.75 d-1, and varied according to age and weight gain. The k values varied between 58.6 and 69.7%, while kg varied between 23.4 and 40.2%. We concluded that NEm and NEg requirements were influenced by age and possibly by the level of stress, nervousness and activity of animals into the respirometry chamber. Further studies should quantify HP with records of positional changes （time spent standing vs. lying down）. Additionally, HP quantification should be repeatedly performed in the same experimental period to

关键词： calorimetry efficiency of energy utilization energy requirements Zebu cattle

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Development of a database for the prediction of phases in Pt-based Superalloys:Cr-Pt-ru

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rare Metals 2006年第5期25卷 597-607页

作者： A.Watson l.A.Cornish r.Süss Institute for Materials research School of ProcessMaterials and Environmental EngineeringUniversity of LeedsLeedsUK Advanced Materials Division MintekPrivate Bag X3015Randburg2125South AfricaDST/NRF Centre of Excellence for Strong MaterialsUniversity of the WitwatersrandJohannesburg2025South Africa Advanced Materials Division MintekPrivate Bag X3015Randburg2125South AfricaDST/NRF Centre of Excellence for Strong MaterialsUniversity of the WitwatersrandJohannesburg2025South Africa School of Chemical and Metallurgical EngineeringUniversity of the WitwatersrandJohannesburg2025South Africa

Work has been ongoing in building a thermodynamic database for the prediction of phase equilibria in Pt-based superalloys. The alloys are being developed for high texture applications in aggressive environments. The database will aid the design of alloys by enabling the calculation of the composition and proportions of phases present in alloys of different compositions. In order to extend this database, a preliminary assessment of the Cr-Pt-ru system has been undertaken, using a combination of Pandat and MTDATA software. As a first step, it was necessary to provide thermodynamic models for the three associated binary systems. Owing to a lack of thermodynamic information for these systems, the binary assessments were based on phase diagrams available in the literature. Using recent experimental phase equilibria data for the ternary system, a preliminary assessment of the Cr-Pt-ru system has been produced. In this preliminary assessment, simplified models were employed for the l12 and sigma phases with a view to extending the descriptions as new experimental information becomes available.

关键词： Cr-Pt-rh thermodynamics assessment phase diagram

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Neuronal avalanches:Sandpiles of self-organized criticality or critical dynamics of brain waves?

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Frontiers of physics 2023年第4期18卷 337-348页

作者： Vitaly l.Galinsky lawrence r.Frank Center for Scientific Computation in Imaging University of California at San DiegoLa JollaCA 92037-0854USA Center for Functional MrI University of California at San DiegoLa JollaCA 92037-0677USA

Analytical expressions for scaling of brain wave spectra derived from the general nonlinear wave Hamiltonian form show excellent agreement with experimental“neuronal avalanche”*** theory of the weakly evanescent nonlinear brain wave dynamics[*** 2,023061(2020);*** Neurosci.32,2178(2020)]reveals the underlying collective processes hidden behind the phenomenological statistical description of the neuronal avalanches and connects together the whole range of brain activity states,from oscillatory wave-like modes,to neuronal avalanches,to incoherent spiking,showing that the neuronal avalanches are just the manifestation of the different nonlinear side of wave processes abundant in cortical *** a more broad way these results show that a system of wave modes interacting through all possible combinations of the third order nonlinear terms described by a general wave Hamiltonian necessarily produces anharmonic wave modes with temporal and spatial scaling properties that follow scale free power *** the best of our knowledge this has never been reported in the physical literature and may be applicable to many physical systems that involve wave processes and not just to neuronal avalanches.

关键词： nonlinear waves critical exponent Hamiltonian system neuronal avalanches critical dynamics

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