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Performance of magnetorheological elastomer based torsional vibration isolation system for dynamic loading conditions

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Journal of Central South University 2020年第1期27卷 144-154页

作者： PRAvEEN Shenoy K KUCHIBHATLA Sai Aditya Raman SINGH Abhishek Kumar GANGADHARAN K v Department of Mechanical Engineering National Institute of Technology KarnatakaSurathkalMangalore-575025India Centre for System Design National Institute of Technology KarnatakaSurathkalMangalore-575025India

vibration isolation is an effective method to mitigate unwanted disturbances arising from dynamic loading conditions. With smart materials as suitable substitutes, the conventional passive isolators have attained attributes of semi-active as well as the active control system. In the present study, the non-homogenous field-dependent isolation capabilities of the magnetorheological elastomer are explored under torsional vibrations. Torsional natural frequency was measured using the serial arrangement of accelerometers. Novel methods are introduced to evaluate the torsional stiffness variations of the isolator for a semi-definite and a motor-coupled rotor system. For the semi-definite system, the isolation effect was studied using the frequency response functions from the modal analysis. The speed-dependent variations for motor-coupled rotor system were assessed using the shift in frequency amplitudes from torque transducers. Finite element method magnetics was used to study the variations in the non-homogenous magnetic field across the elastomer. The response functions for the semi-definite rotor system reveal a shift in the frequency in the effect of the magnetic field. Speed-dependent variations in the frequency domain indicate an increment of 9% in the resonant frequency of the system.

关键词： torsional vibration isolation semi-definite system magnetorheological elastomer speed-dependent isolation

Risk Assessment of Aircraft’s Lateral veer-off the Runway Surface during Landing

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Open Journal of Applied Sciences 2023年第8期13卷 1246-1256页

作者： victor v. Stolyarov Allam Jamal-Eddine Faculty of Transport Construction Yuri Gagarin State Technical University of Saratov Saratov City The Russian Federation

This article presents a methodology to determine the risk of aircrafts lateral runway excursion during landing via mathematical risk modeling. In addition, the methodology is demonstrated by means of detailed calculation of the lateral runway excursion risk value during the landing of the aircraft Airbus A310-200, in view of the maximum landing weight and the appropriate range of landing velocities according to the International Civil Aviation Organization specification. Obviously, the calculation demonstrates that the developed math solutions and equations presented herein are powerful tools to evaluate the risk of lateral runway excursion of the majority of aircrafts and for any airport. The method is also applicable to assess the residual level of risk at any specific airport and its deviation compared to the recommended safety level. Consequently, the presented mathematical solutions to determine the risk rate of lateral runway excursion during landing offers airports’ operational and safety management departments a viable tool so that appropriate measurements could be adopted. Finally, it is a methodology not only to assess the risk but also to determine the appropriate runway width.

关键词： Risk Runways veer-off Aircraft Design

Downregulation of the Basic Peroxidase Isoenzyme from Zinnia elegans by Gibberellic Acid

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Journal of Integrative Plant Biology 2010年第2期52卷 244-251页

作者： María Josefa López Núez-Flores Jorge Gutirrez Laura v.Gómez-Ros Esther Novo Uzal Mariana Sottomayor Alfonso Ros Barceló Department of Plant Biology University of MurciaE-30100MurciaSpain Department of Plant Biology University of La CoruaE-15071La CorunaSpain IBMC University of Porto4150 PortoPortugal

Hypocotyl formation during the epigeal germination of seedlings is under strict hormonal regulation. In a 3 d old Zinnia elegans seedling system, gibberellic acid （GA3） exerts an opposite effect to that exerted by light on hypocotyl photomorphogenesis because GAz promotes an etiolated-like growth with an inhibition of radial （secondary） growth. For this reason, the effect of GA3 on the basic peroxidase isoenzyme from Z. elegans （ZePrx）, an enzyme involved in hypocotyl lignin biosynthesis, was studied. The results showed that GA3 reduces ZePrx activity, similarly to the way in which it reduces seedling secondary growth. This hormonal response is supported by the analysis of the ZePrx promoter, which contains four types of GA3-responsive ***： the W Box/O2S; the Pyr Box; the GARE; and the Amy Box. Taken together, these results suggest that ZePrx is directly regulated by GA3, with this effect matching the inhibitory effect of GA on the hypocotyl secondary growth.

关键词： GA Downregulation of the Basic Peroxidase Isoenzyme from Zinnia elegans by Gibberellic Acid cis Figure

Characterization of functionalized multiwalled carbon nanotubes and application as an effective filter for heavy metal removal from aqueous solutions

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Chinese Journal of Chemical Engineering 2016年第12期24卷 1695-1702页

作者： Emad.M.Elsehly N.G.Chechenin A.v.Makunin H.A.Motaweh E.A.vorobyeva K.A.Bukunov E.G.Leksina A.B.Priselkova Skobeltsyn Institute of Nuclear Physics Lomonosov Moscow State University Faculty of Science Damanhour University Faculty of Physics Lomonosov Moscow State University

Filtration efficiency of Ni(II) from aqueous solution using pristine and modified MWCNTs filters was investigated as a function of Ni(II) ion concentration, p H, and filter mass. MWCNTs were synthesized by CvD method and modified using two complementary treatments, purification(using a mixture of hydrochloric acid and hydrogen peroxide) and functionalization(using nitric acid). The effect and mechanism of each treatment on the structural integrity of pristine MWCNTs has been studied. Morphology of the pristine and modified filters was investigated by Raman Spectrometry(RS), Scanning Electron Microscopy(SEM), Energy Dispersive X-ray Spectroscopy(EDS),Fourier Transform Infrared(FTIR) spectrometry and Thermogravimetric analysis. It was found from Raman spectra that the ratio of the intensity of D-band to that of G-band decreased by purification process, and increased by functionalization process. The adsorption mechanism of Ni(II) onto the surface functional groups of modified MWCNTs was confirmed by FTIR spectrum. The filtration results showed that the removal efficiency of Ni(II) is strongly dependent on pH and could reach 85% at pH = 8. Also, modified MWCNT filters can be reused through many cycles of regeneration with high performance. Functionalized MWCNTs filters may be a promising adsorbent candidate for heavy metal removal from wastewater.

关键词： MWCNTs filters Functionalization Nickel removal Filtration Raman spectrometry Purification

An Event Horizon Imager(EHI) Mission Concept Utilizing Medium Earth Orbit Sub-mm Interferometry

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空间科学学报 2021年第2期41卷 211-233页

作者： KUDRIASHOv v MARTIN-NEIRA M ROELOFS F FALCKE H BRINKERINK C BARYSHEv A HOGERHEIJDE M YOUNG A POURSHAGHAGHI H KLEIN-WOLT M MOSCIBRODZKA M DAvELAAR J BARAT I DUESMANN B vALENTA v PERDIGUES ARMENGOL J M DE WILDE D MARTIN IGLESIAS P ALAGHA N vAN DER vORST M Department of Astrophysics/IMAPP Radboud University NijmegenP.O.Box 90106500 GL Nijmegenthe Netherlands ESTEC/ESA Keplerlaan 12201 A2 Noordurigkthe Netherlands Mar Planck Institute for Radio Astrorny Auf dem Higel 69D-53121 Bon(Endenich)Germany University of Groningen Landleven 129747 AD Groningenthe Netherlands Leiden Observatory Leiden UniversityPO Box 95132300 RALeidenthe Netherlands Anton Pannekoek Institute for Astronomy University of AmsterdamScience Park 9041098 XHAmsterdamthe Netherlands Center for Computational Astrophysics Flatiron Institute162 Fifth AvenueNew YorkNY 10010USA

Submillimeter interferometry has the potential to image supermassive black holes on event horizon scales,providing tests of the theory of general relativity and increasing our understanding of black hole accretion *** Event Horizon Telescope(EHT) performs these observations from the ground,and its main imaging targets are Sagittarius A~* in the Galactic Center and the black hole at the center of the M87 ***,the EHT is fundamentally limited in its performance by atmospheric effects and sparse terrestrial(u,v)-coverage(Fourier sampling of the image).The scientific interest in quantitative studies of the horizon size and shape of these black holes has motivated studies into using space interferometry which is free of these *** resolution considerations and interstellar scattering effects push the desired observing frequency to bands above 500 *** paper presents the requirements for meeting these science goals,describes the concept of interferometry from Polar or Equatorial Medium Earth Orbits(PECMEO) which we dub the Event Horizon Imager(EHI),and utilizes suitable space technology *** this concept,two or three satellites orbit at slightly different orbital radii,resulting in a dense and uniform spiral-shaped(u,v)-coverage over *** local oscillator signals are shared via an inter-satellite link,and the data streams are correlated on-board before final processing on the ***-satellite metrology and satellite positioning are extensively employed to facilitate the knowledge of the instrument position vector,and its time *** European space heritage usable for both the front ends and the antenna technology of such an instrument is *** and future sensors for the required inter-satellite metrology are *** performance estimates and simulation results are given.

关键词： Instrumentation Space vLBI Radio Telescopes

ON THE NONLINEARTIMOSHENKO-KIRCHHOFF BEAM EQUATION

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Chinese Annals of Mathematics,Series B 1999年第4期20卷 495-506页

作者： A. AROSIO(Dipatimento di Matematica, Univ. Parma, v. d’Azeglio 85A, 43100 Parma, Italy)E-mail: arosio＠prmat.math.unipr.it Univ Parma Dipartimento Matemat I-43100 Parma Italy

When an elastic string with fixed ends is subjected to transverse vibrations, its length varies with the time: this introduces changes of the tension in the string. This induced Kirchhoff to propose a nonlinear correction of the classical D’Alembert equation. Later on, WoinowskyKrieger (Nash & Modeer) incorporated this correction in the classical Euler-Bernoulli equation for the beam (plate) with hinged *** a new equation for the small transverse vibrations of a simply supported beam is proposed. Such equation takes into account Kirchhoff’s correction, as well as the correction for rotary inertia of the cross section Of the beam and the influence of shearing strains, already present in the Timoshenko beam equation (of the Mindlin-Timoshenko equation for the plate).The model is inspired by a remark of Rayleigh, and by a joint paper with Panizzi & Paoli. It looks more complicated than the one proposed by Sapir & Reiss, but as a matter of fact it is easier to study if a suitable change of variables is *** author proves the local well-posedness of the initial-boundary value problem in Sobolev spaces of order ≥2.5. The technique is abstract, i.e. the equation is rewritten as a fourth order evolution equation in Hilbert space (thus the results could be applied also to the formally analogous equation for the plate).

关键词： Timoshenko-Kirchhiff beam equation Local well-posedness Fourth order evolution equation

Clinical anatomy: a problem solving approach[2nd ed] 2

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2012年

作者： Neeta v. Kulkarni

来源：畅想之星图书光盘版（南... 评论

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农牧交错带不同利用方式下草原土壤的变化

土壤 1998年第5期30卷 225-229页

作者：刘良梧周建民刘多森 I.v.Ivanov v.A.Gemkin v.Y.Prikod’ko 中国科学院南京土壤研究所南京210008 InstituteofSoilScienceandPhotosynthesisRSA puschino142292

以半干旱农牧交错带的典型土壤类型──具有过渡特性的、质地较砂、肥力一般的粟钙土为代表，从轻度放牧疏林草地、轻度放牧草地和重度放牧草地，以及耕地的不同利用方式下，土壤物理性质、化学性质和生物学性质的角度，阐明了草原土壤... 详细信息

以半干旱农牧交错带的典型土壤类型──具有过渡特性的、质地较砂、肥力一般的粟钙土为代表，从轻度放牧疏林草地、轻度放牧草地和重度放牧草地，以及耕地的不同利用方式下，土壤物理性质、化学性质和生物学性质的角度，阐明了草原土壤的变化。进而指出，在干旱农牧交错带生态环境脆弱背景下，人为的滥垦和不合理的管理，以及过度放牧是引起土壤紧实度增加，土壤蚀沙化和土壤养分丧失的主导因素。

关键词：农牧交错带栗钙土土壤变化草原土壤

A high-throughput data analysis and materials discovery tool for strongly correlated materials

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npj Computational Materials 2018年第1期4卷 138-146页

作者： Hasnain Hafiz Adnan Ibne Khair Hongchul Choi Abdullah Mueen Arun Bansil Stephan Eidenbenz John Wills Jian-Xin Zhu Alexander v.Balatsky Towfiq Ahmed Department of Physics Northeastern UniversityBostonMA 02119USA Department of Computer Science University of New MexicoAlbuquerqueNM 87131USA Theoretical Division Los Alamos National LaboratoryLos AlamosNM 87545USA The Information Science and Technology Institute Los Alamos National LaboratoryLos AlamosNM 87545USA Nordita KTH Royal Institute of Technology and Stockholm UniversityRoslagstullsbacken 23Stockholm SE-10691Sweden Department of Physics University of ConnecticutStorrsCT 06269USA Department of Mechanical Engineering Carnegie Mellon UniversityPittsburghPA 15213USA

Modeling of f-electron systems is challenging due to the complex interplay of the effects of spin–orbit coupling,electron–electron interactions,and the hybridization of the localized f-electrons with itinerant conduction *** complexity drives not only the richness of electronic properties but also makes these materials suitable for diverse technological *** this context,we propose and implement a data-driven approach to aid the materials discovery *** deploying state-of-the-art algorithms and query tools,we train our learning models using a large,simulated dataset based on existing actinide and lanthanide *** machine-learned models so obtained can then be used to search for new classes of stable materials with desired electronic and physical *** discuss the basic structure of our f-electron database,and our approach towards cleaning and correcting the structure data *** examples of the applications of our database include successful prediction of stable superstructures of double perovskites and identification of a number of physically-relevant trends in strongly correlated features of f-electron based materials.

关键词： database desired conduction