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Particuology 2015年第6期13卷 68-74页

作者： Seiyed E. Ghasemi M. Vatani d.d. Ganji Young Researchers and Elite Club Qaemshahr Branch Islamic Azad University Qaemshahr lran department of Mechanical Engineering Babol University of Technology Babol lran

The motion of a spherical particle released in a swirling fluid flow is studied employing the least-squares method and method of moments. The governing equations are obtained and solved employing the two methods. The accuracy of the results is examined against the results of a fourth-order Runge-Kutta numer- ical method. The effects of various parameters, namely the initial radius, initial radial velocity, initial angular velocity, and drag-to-inertia ratio, on the non-dimensional velocity profiles and particle position distribution are considered. The results show that the radial velocity increases over time while the angular velocity decreases, and that an increase in the initial radial velocity increases the particle radial distance and angular velocity but decreases the radial velocity profile.

关键词： Spherical particle Swirling flow Radial velocity Angular velocity Least-squares method Method of moments

Snapshot imaging of ultrashort electron bunches

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Light(Science & Applications) 2024年第7期13卷 1226-1228页

作者： Andreas döpp Ludwig-Maximilian-Universität München Am Coulombwall 185748GarchingGermany Max Planck Institut für Quantenoptik Hans-Kopfermann-Strasse 1Garching85748Germany

New measurements combine spatial and temporal information from optical transition radiation to estimate the three-dimensional structure of electron bunches from a laser wakefield accelerator.

关键词： ultrashort Snapshot electron

Cultured meat in western media: The disproportionate coverage of vegetarian reactions, demographic realities, and implications for cultured meat marketing

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Journal of Integrative Agriculture 2015年第2期14卷 264-272页

作者： Patrick d Hopkins department of Philosophy Millsaps College Center for Bioethics University of Mississippi Medical CenterJackson MS 39210USA

This paper examines the media coverage of the 2013 London cultured meat tasting event, particularly in the United States, Canada, and the United Kingdom. Using major news outlets, prominent magazines covering food and science issues, and advocacy websites concerning meat consumption, the paper characterizes the overall emphases of the coverage, the tenor of the coverage, and compares the media portrayal of the important issues to the demographic and psychological realities of the actual consumer market into which cultured meat will compete. In particular, the paper argues that Western media gives a distorted picture of what obstacles are in the path of cultured meat acceptance, especially by overemphasizing and overrepresenting the importance of the reception of cultured meat among vegetarians. Promoters of cultured meat should recognize the skewed impression that this media coverage provides and pay attention to the demographic data that suggests strict vegetarians are a demographically negligible group. Resources for promoting cultured meat should focus on the empirical demographics of the consumer market and the empirical psychology of mainstream consumers.

关键词： cultured meat vegetarianism vegans Mark Post in vitro meat moral psychology consumer market disgust

Effects of human disturbance on nest placement of the woodpigeon (Columba palumbus): a case study from the Middle Atlas, Morocco

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Integrative Zoology 2014年第3期9卷 349-359页

作者： Saâd HANANE Forest Research Center High Commissariat for WaterForests and Desertification ControlRabat-AgdalMorocco

The woodpigeon(Columba palumbus)is a common and widespread bird in Morocco(North Africa).I examined,over 2 years(2010 and 2011),the breeding density and nest placement of this game species in relation to nest site habitat and degree of human *** study area was in the Middle Atlas Tighboula mountain forest,Morocco,in a disturbed and an undisturbed *** data collected in the 2 study sites,I aimed to identify the factors influencing the placement of nests within holm oak trees(Quercus rotundifolia)and their densities.I found that habitat structures,influenced by grazing disturbance,have affected nesting density and the location of nests of this *** place their nests in a higher position(3.42±0.19 m)when disturbance intensity is high and lower(1.68±0.1 m)when disturbance intensity is low,and show higher nesting density in less disturbed zone(3.1±0.4 nests/ha)than in highly disturbed zones(1.4±0.2 nests/ha).Grazing disturbance could pose a threat to population persistence at a broader scale and could potentially reduce the abundance of this species by altering the composition and the structure of the forest nesting *** multi-scale studies are needed to assess the effects of different levels of grazing disturbance on woodpigeon nest density and placement,and to enhance our knowledge of the breeding behavior of this game species under variable environments.

关键词： breeding density Columba palumbus holm oak Middle Atlas Morocco nest location woodpigeon

Reconstructing the Potential Function in a Formulation of Quantum Mechanics Based on Orthogonal Polynomials

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Communications in Theoretical Physics 2017年第12期67卷 711-728页

作者： A.d.Alhaidari Saudi Center for Theoretical Physics

In a recent reformulation of quantum mechanics, the properties of the physical system are derived from orthogonal polynomials that make up the expansion coefficients of the wavefunction in a complete set of square integrable basis. Here, we show how to reconstruct the potential function so that a correspondence with the standard formulation could be established. However, the correspondence places restriction on the kinematics of such problems.

关键词： wavefunction potential function orthogonal polynomials recursion relation tridiagonal representations asymptotics

Inverse dynamics and servomotor parameter estimation of a 2-dOF spherical parallel mechanism

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Science China(Technological Sciences) 2008年第3期51卷 288-301页

作者： d G CHETWYNd School of Engineering The University of Warwick

A novel reconfigurable 5-dOF hybrid manipulator―TriVariant-B is composed of a 2-dOF spherical parallel mechanism which is serially connected with a 3-dOF open-loop kinematic chain undergoing one translation and two rotations by a prismatic joint. The merit of this design is that a relatively large workspace/limb- stroke ratio can be achieved thanks to the decomposition of the fixed point rotation and the relative translation. In this paper, on the basis of inverse dynamic formula- tion of the 2-dOF spherical parallel mechanism, an approach is proposed for esti- mating the servomotor parameters including moment of inertia, rated speed and the maximum torque in a quick manner. The approach has been employed for the development of a prototype for frame cutting process.

关键词： parallel kinematic machine inverse dynamics servomotor parameters

Validation of the NATO Armaments Ballistic Kernel for use in small-arms fire control systems

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defence Technology（防务技术） 2017年第3期13卷 188-199页

作者： d.Corriveau defence R&d Canada

In support for the development of a new small-arm ballistic computer based on the NATO Armaments Ballistic Kernel(NABK) for the Canadian snipers, dRdC Valcartier Research Centre was asked to carry out high-fidelity 6 degree-of-freedom(6-dOF) trajectory simulations for a set of relevant vignettes for the snipers, and to compare the direct fire 6-dOF simulation results with those obtained with the 4-dOF NATO Armaments Ballistic Kernel(NABK) adapted to simulate small-arm ammunition trajectories. To conduct this study, dRdC Valcartier Research Centre used BALCO v1.0b. This paper presents(1) the process and the methodology employed to carry out the sniper direct fire solution study,(2) the modeling and the simulation of the sniper projectile, the approach used in calculating the firing solutions, and the results of direct fire simulations for the sniper vignettes, and(3) an analysis of firing solutions obtained with the BALCO engine versus those of NABK. The work presented in this paper serves to validate the use of NABK for the new sniper ballistic computer.

关键词：弹道计算机武器火控系统北约验证应用 dRdC 轨迹模拟狙击手

On direct Limits of Finite Products of Fields as Subrings of a Commutative Ring

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Algebra Colloquium 2016年第2期23卷 243-249页

作者： d. Karim department of Mathematics Faculty of Nador University Mohamed First P.O. Box 300 62702 Nador Morocco

Let R be a commutative ring. In this paper, we develop the existence of direct limits of finite products of fields as subrings of R.

关键词： Artinian ring direct limit of finite products of fields infinite product von Neumann regular ring zero-dimensional ring

distinct expression profiles of transcriptional coactivators for thyroid hormone receptors during Xenopus laevis metamorphosis

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Cell Research 2003年第6期13卷 459-464页

作者： BINdU d PAUL National Institutes of Health Laboratory of Gene Regulation and development National Institute of Child Health and Human development Bldg. USA.

The biological effects of thyroid hormone (T3) are mediated by the thyroid hormone receptor (TR). Amphibian metamorphosis is one of the most dramatic processes that are dependent on T3. T3 regulates a series of orchestrated developmental changes, which ultimately result in the conversion of an aquatic herbivorous tadpole to a terrestrial carnivorous frog. T3 is presumed to bind to TRs, which in turn recruit coactivators, leading to gene activation. The best-studied coactivators belong to the p160 or SRC family. Members of this family include SRC1/ NCoA-1, SRC2/TIF2/GRIP1, and SRC3/pCIP/ACTR/AIB-l/RAC-3/TRAM-1. These SRCs interact directly with liganded TR and function as adapter molecules to recruit other coactivators such as p300/CBP. Here, we studied the expression patterns of these coactivators during various stages of development. Amongst the coactivators cloned in Xenopus laevis, SRC3 was found to be dramatically upregulated during natural and T3-induced metamorphosis, and SRC2 and p300 are express

关键词： transcription coactivators thyroid hormone receptor Xenopus laevis metamorphosis histone acetylation.

Nanocrystalline and Nanocomposite Magnetic Materials and Their Applications

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Journal of Iron and Steel Research International 2007年第4期14卷 69-74页

作者： Robert d Shull Magnetic Materials Group National Institute of Standards and TechnologyGaithersburg MD 20899MarylandUSA

Nanocrystalline materials can possess bulk properties quite different from those commonly associated with conventional large-grained materials. Nanocomposites, a subset of nanocrystalline materials, in addition have been found to possess magnetic properties which are similar to, but different from, the properties of the individual constituents. New magnetic phenomena, unusual property combinations, and both enhanced and diminished magnetic property values are just some of the changes observed in magnetic nanocomposites from conventional magnetic materials. Here, a description will be presented of some of the exciting new properties discovered in nanomaterials and the magnetic applications envisioned for them.

关键词： nanocomposite ferromagnet magnetoresistance magnetic refrigeration domain imaging