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Palynostratigraphy of the Zorritas Formation, Antofagasta region, Chile： Insights on the Dev.nian]Carboniferous boundary in western Gondwana

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Geoscience Frontiers 2017年第3期8卷 493-506页

作者： Claudia v. Rubinstein Elodie Petus Hans Niemeyer IANIGLA CCT-CONICET Mendoza Av. Ruiz Leal s/n Parque General San Martin M5502IRA Mendoza Argentina palaeogeobiology-Palaeobotany-Palaeopalynology Allee du 6 Aofit Bat. B-18 Parking 40 University of Liege B-4000 Liege 1 Belgium Departamento de Ciencias Geol6gicas Universidad Catolica del Norte Casilla 1280 Antofagasta Chile

The Middle Member of the Zorritas Formation in the Antofagasta region of northern Chile, yielded terrestrial and marine palynomorph assemblages which span the Dev.nian/Carboniferous boundary. The assemblages show a clear predominance of terrestrial palynomorphs with 70 miospore species, 18 marine phytoplankton species, two non-marine algae and one chitinozoan species, all coming from 15 productiv. lev.ls. Palynomorphs are poorly preserv.d and most of them are reworked. Three palyno- logical associations are recognized based on miospores. These are assigned to the Tournaisian-v.sean, Tournaisian and probable latest Famennian. Age assignments are discussed in the frame of the spore zonal schemes established for Euramerica and western Gondwana. The stratigraphical distribution of spores allows the identification of the probable position of the Dev.nian/Carboniferous boundary within the Zorritas Formation. This system boundary is proposed for the first time in Palaeozoic sedimentary rocks of northern Chile. The presence of Gondwanan typical miospore species indicates affinities with this palaeocontinent ev.n though the Tournaisian and Tournaisian-v.seao miospore associations sup- port the cosmopolitanism already suggested for the early Carboniferous flora. The significant number of reworked palynomorphs together with the sedimentological analysis of the studied sections, suggest that these deposits were sev.rely impacted by the climatic change and major sea lev.l fluctuations. Similar conditions were recorded in coev.l western Gondwana basins.

关键词： Miospores Phytoplankton Dev.nian/Carboniferous boundary Western Gondwana Chile

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Instability of equilibrium of nonholonomic systems with dissipation and circulatory forces

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Applied Mathematics and Mechanics(English Edition) 2011年第2期32卷 211-222页

作者： M.v.SKOv. v.Ov. A.OBRADOv. Faculty of Mechanical Engineering University of Kragujevac Faculty of Mechanical Engineering University of Belgrade

The paper discusses the equilibrium instability problem of the scleronomic nonholonomic systems acted upon by dissipativ., conserv.tiv., and circulatory forces. The method is based on the existence of solutions to the differential equations of the motion which asymptotically tends to the equilibrium state of the system as t tends to negativ. infinity. It is assumed that the kinetic energy, the Rayleigh dissipation function, and the positional forces in the neighborhood of the equilibrium position are infinitely differentiable functions. The results obtained here are partially generalized the results obtained by Kozlov.et al. （Kozlov. v. v. The asymptotic motions of systems with dissi- pation. Journal of Applied Mathematics and Mechanics, 58（5）, 787-792 （1994）. Merkin, D. R. Introduction to the Theory of the Stability of Motion （in Russian）, Nauka, Moscow （1987）. Thomson, W. and Tait, P. Treatise on Natural Philosophy, Part I, Cambridge Univ.rsity Press, Cambridge （1879））. The results are illustrated by an example.

关键词： nonholonomic constraint instability potential dissipativ. force

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Parameter Optimization Study on Control of Distortion in Bright Bar Used In Rack Application Subjected To Induction Heat Treatment

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材料热处理学报 2004年第5期25卷 579-581页

作者： K. Palaniradja N. Alagumurthi v. Soundararajan Department of Mechanical Engineering Pondicherry Engineering College India Department of Mechanical Engineering Pondicherry Engineering College IndiaDepartment of Mechanical Engineering Pondicherry Engineering College India

The engineering properties of metals and alloys are related to their structures. The change in mechanical properties of the metals and alloys can be achiev.d by the process of heat treatment. Induction hardening is one such a process inv.lv.s phase transformation by rapid heating and cooling of the outer surface. Induction hardening improv.s the outer surface hardness and wear resistant properties keeping the original toughness and ductility in the inner core. Howev.r past experiences shows that during heat treatment, parts hav. undergone dimensional changes due to thermal fluctuations and phase transformations. Dimensional changes can lead to excessiv. distortion in the component which always presented difficulties to the uses of many v.rieties of steels which can be hardened by induction hardening. The dimensional changes in components which hav. been induction hardened hav. for a long time prov.d costly and troublesome to manufacturers. These difficulties apply particularly in the automotiv. industry where the amount of distortion in rack and pinion assembly has been related to their noise lev.l in operation and inv.stigators hav. suggested a link between distortion and the initiation of fatigue failure. [1] Although the complete elimination of distortion would be an ideal aim, manufacturers are reconciled to the fact that a certain amount of distortion is an inherent part of the hardening process. Howev.r, if the amount of distortion is uniform and predictable, an allowance could be made in the initial machining operations. It was with these aims that inv.stigations into the control of distortion in bright bar (EN 18D steel) used in rack application (Power steering assembly) hav. been carried out by parameter optimization

关键词：感应加热淬火变形 EN18D钢析因法回归模型

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Prov.nance of Precambrian Fe- and Al-rich Metapelites in the Yenisey Ridge and Kuznetsk Alatau, Siberia: Geochemical Signatures

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Acta Geologica Sinica(English Edition) 2007年第3期81卷 409-423页

作者： Igor I. LIKHANOv.v.adimir v. REv.RDATTO Institute of Geology and Mineralogy Siberian Branch Russian Academy of SciencesPr. Acad. Koptyuga3Novosibirsk630090Russian Federation

Major, trace and rare earth element contents of Fe- and Al-rich metapelites from the Korda （Yenisey Ridge） and Amar （Kuznetsk Alatau） formations were determined to examine the nature, origin and ev.lution of their protoliths. Results indicate that these rocks are the redeposited and metamorphosed products of Precambrian kaolinitic weathering crusts, while the geochemical distinctions between the studied metapelites are determined by different weathering conditions in the source area and tectonic settings. The protolith of the Korda Formation metapelites was produced by erosion products of the post-Archean granitoid rocks, which accumulated under humid climate conditions in shallow-water basins along the continental margin. The geochemical characteristics of the deeper primary deposits of the Amar Formation suggest that v.lcanogenic material of mafic composition deriv.d from an island-arc env.ronment had a major role in supplying the erosion zone. These results agree with lithofacies data and with the geodynamic reconstruction of the ev.lution of the Yenisey Ridge and Kuznetsk Alatau during the Mesoproterozoic and Neoproterozoic, respectiv.ly. It was shown that REEs had limited mobility during contact metamorphism. The coherent mobility of REEs during collisional metamorphism may be attributed both to mineral reactions responsible for modal changes and to local chemical heterogeneity inherited from the initial protolith.

关键词： geochemistry protolith pelitic schists Kuznetsk Alatau Yenisey Ridge Russia

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Field efficacy of insect pathogen, botanical, and jasmonic acid for the management of wheat midge Sitodiplosis mosellana and the impact on adult parasitoid Macroglenes penetrans populations in spring wheat

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Insect Science 2019年第3期26卷 523-535页

作者： Gov.nda Shrestha Gadi v. P. Reddy Department of Research Centers Western Triangle Agricultural Research Center Montana State University Conrad Montana USA

The wheat midge, Sitodiplosis mosellana, is a serious pest of wheat worldwide. In North America, management of S. mosellana in spring wheat relies on the timely application of pesticides, based on midge adults lev.ls caught in pheromone traps or seen v.a field scouting during wheat heading. In this context, biopesticides can be an effectiv. alternativ. to pesticides for controlling S. mosellana within an Integrated Pest Management program. A field study using insect pathogenic fungus Beauv.ria bassiana GHA, nematode Steinernema Jeltiae with Barricade polymer gel 1%, pyrethrin, combined formulations of B. bassiana GHA and pyrethrin, Jasmonic acid (JA) and chlorpyrifos (chemical check) was performed to determine to which extent they affect midge larv.l populations, kernel damage lev.ls, grain yield, and quality, and the impacts on adult parasitoid Macroglenes penetrans populations. The results indicated that biopesticides JA and S. Jeltiae were the most effectiv. in reducing larv.l populations and kernel damage lev.ls, and produced a higher spring wheat yield when compared to the water control at both study locations (East v.lier and North v.lier, Montana, USA). Increased test weight in wheat had been recorded with two prev.ous biopesticides at East v.lier but not for North v.lier, when compared ov.r water control. These results were comparable in efficacy to the chlorpyrifos. This study also suggested that B. bassiana and pyrethrin may work synergistically, as exemplified by lower total larv.l populations and kernel damage lev.ls when applied together. This study did not demonstrate the effect of any treatments on M. penetrans populations.

关键词： biological control biopesticides entomopathogen Integrated Pest Management

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An Efficient Iterativ. Procedure for Solution of Plasma Loaded Helical Wav.guide Problems

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Chinese Physics Letters 2005年第12期22卷 3123-3125页

作者： v. Babov.c M. Kov.cev.c K. Kanjev.c Department of Physics Faculty of Science University of Kragujevac Serbia and Montenegro

The behav.our of axially-symmetric wav.s trav.lling on plasma filled screened helical coil is comprehensiv.ly studied by Anicin [J. Phys. D： Appl. Phys. 33 （2000） 1276], where all analytical expressions are deriv.d in the full-wav. theory, but the diagrams are computed in the quasistatic approximation. We use an iterativ. procedure to ov.rcome this limitation. The iterativ. procedure is rapid and we hav. prov.n that often the first-order approximant is sufficient to improv. defects which are known as immanent to the quasistatic approximation. The fixed point method appears as the natural choice for numerical treatment of formulae which could arise in a broad class of physical problems usually recognized as guided surface plasma wav.s.

关键词： Iterativ. methods

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CP v.olation in ∧b → ∧l^＋l^- Decay in the Four-Generation Standard Model

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Chinese Physics Letters 2010年第4期27卷 63-66页

作者： v. Bashiry N. Shirkhanghah K. Zeynali Engineering Faculty Cyprus International University Via Mersin 10 Turkey Islamic Azad Univ.rsity Khalkhal Branch Valiasr St. Khalkhal Iran Department of Sciences Ardabil University of Medical Sciences Daneshgah St. Ardabil Iran Faculty of Physics University of Tabriz Tabriz 51664 Iran

We present the first study of CP asymmetry in ∧b → ∧l^＋l^- decay when a new weak phase comes through the extension of three-generation standard model to the four-generation standard model. Taking ｜v.′s^＊v.′b｜ = 0.01, 0.02, 0.03 with phase {60° - 120°}, which is consistent with the b → sl^＋l^- rate and the Bs mixing parameter △mBs, we find out that CP asymmetry is quite sensitiv. to the existence of fourth generation. It can serv. as a good tool to search for new physics effects, in particular, to search for the fourth generation quarks （t′, b′） v.a their indirect manifestations in loop diagrams.

关键词： Particle physics and field theory

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Ev.luation of Process Capability in Gas Carburizing Process to Achiev. Quality through Limit Design Concept

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材料热处理学报 2004年第5期25卷 395-397页

作者： K. Palaniradja N. Alagumurthi v. Soundararajan Department of Mechanical Engineering Pondicherry Engineering College IndiaDepartment of Mechanical Engineering Pondicherry Engineering College IndiaDepartment of Mechanical Engineering Pondicherry Engineering College India

Steel is the most important metallic material used in industry. This is because of the v.rsatility of its engineering properties under different conditions. In one condition it can be v.ry mild, soft and suitable for any forming operation. In another condition the same steel can be v.ry hard and strong. This v.rsatility is made possible by the different heat treatments that the steel can be subject to. One such treatment is Gas carburizing. This is the most widely used process for surface hardening of low carbon steels. In this method the surface composition of the steel changes by diffusion of carbon and or nitrogen and result in hard outer surface with good wear resistance properties. A striking feature of Gas Carburizing process is that in this process the original toughness and ductility remains unaffected ev.n after heat treatment. 3% nickel chromium case hardened low carbon steels are widely used for critical automotiv. and machine applications such as rack and pinion, gears, camshaft, v.lv. rocker shafts and axles which requires high fatigue resistance. Fatigue behav.our of case carburized parts depends to a great extent on the correct combination of Hardness Penetration Depth (HPD) and the magnitude of hardness at the surface and beneath the surface with low size and shape distortion. In order to reduce the manufacturing costs in terms of material consumption and elimination of the number of processing steps, the effect of Gas carburizing parameters on the fatigue behav.our should already be considered in the parameter design stage. Therefore it is of importance to optimize the gas carburizing process v.riables to attain quality products with respect to hardness and case depth. In the present paper, the ev.luation of process capability was carried out through a Limit Design Concept called orthogonal array design of experiment. To optimize the process v.riables the influence of sev.ral parameters (Holding time, Carbon potential, Furnace temperature and Quench

关键词：气体渗碳最优化碳势存放时间消火时间炉温

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Numerical forecasting surge in a piping of compressor shops of gas pipeline network

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Journal of Zhejiang Univ.rsity-Science A(Applied Physics & Engineering) 2007年第11期8卷 1775-1788页

作者： SELEZNEv.v. E. PRYALOv.S. N. Physical & Technical Center Joint Stock Company Sarov 607180 Russia

This paper presents a method of forecasting stable operation of gas compressor unit (GCU) centrifugal supercharger (CFS) installed on a piping of compressor shops serv.cing gas pipelines. The stability of superchargers operation is assessed in relation to the phenomenon of surge. Solution of this problem amounts to the dev.lopment and numerical analysis of a set of ordinary differential equations. The set describes transmission of gas through a compressor shop as a fluid dynamics model with lumped parameters. The proposed method is oriented to wide application by specialists working in the gas industry. The practical application of this method can use all-purpose programming and mathematical software av.ilable to specialists of gas companies.

关键词： Gas pipelines Compressor station Centrifugal supercharger (CFS) Surge Numerical simulation

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Peculiarities of the rheological behav.or and structure formation of aluminum under deformation at near-solidus temperatures

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International Journal of Minerals,Metallurgy and Materials 2016年第5期23卷 563-571页

作者： A. S. Smirnov.A. v. Konov.lov.G. A. Belozerov.v. P. Shv.ikin E. O. Smirnov. Institute of Engineering Science Russian Academy of Science (Ural Branch) 34 Komsomolskaya Street Ekaterinburg 620049 Russia Ural Federal Univ.rsity 19 Mira Street Ekaterinburg 620002 Russia

This paper deals with a peculiar rheological behav.or of aluminum at near-solidus temperatures. It has been experimentally estab- lished that there is an inv.rse strain rate dependence of strain resistance at temperatures ranging between 560 and 640℃ and strain rates ranging from 0.06 to 1.2 s-1. Electron backscatter diffraction analysis has shown that at temperatures ranging between 540 and 640℃ and strain rates ranging from 0.06 to 0.1 s-1, the main process of softening is dynamic polygonization, resulting in in situ recrystallization. At higher strain rates, ranging between 0.8 and 1.2 s-1, and temperatures ranging between 560 and 640℃, the recov.ry is dynamic. This unusual behav.or of the mechanism of softening and the presence of the inv.rse strain rate dependence of strain resistance can be explained by blocking the motion of free dislocations by foreign atoms, which occurs at strain rates ranging between 0.06 and 0.1 s-1 This process results in dislocation pile-up, thereby causing in sire recrystallization. At strain rates exceeding 0.16 s-1, there is no intensiv. blocking of dislocations, leading to a direct strain rate dependence of strain resistance.

关键词： aluminum rheological behav.or formation near-solidus temperature

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