986 research outputs found
A Magnetorheological Damper with Embedded Piezoelectric Force Sensor: Experiment and Modeling
This chapter describes configuration, fabrication, calibration and performance tests of the devised self-sensing MR damper firstly. Then, a black-box identification approach for modeling the forward and inverse dynamics of the self-sensing MR damper is presented, which is developed with the synthesis of NARX model and neural network within a Bayesian inference framework to have the ability of enhancing generalization.Department of Civil and Environmental Engineerin
Experimental Study of Explosion Limits of Refrigerants and Lubricantsâ Mixture
The explosion limits of refrigerants and lubricantsâ mixture were studied. The refrigerants like R161, R1234yf and R152a are combustible. Lubricants, to a certain extent, are combustion-supporting. In many actual conditions, lubricants and refrigerants are mixed together. In this paper, a test device which can be run automatically was established according to ASTM E681-09, and the explosive experimental of refrigerants and lubricantsâ mixture in some ratio was studied. By altering the proportions of refrigerants and lubricants, we got curve and scope of explosions. In some certain ratio, refrigerants and lubricantsâ mixture has different explosion limits compared to refrigerants with no lubricants in it
Sulphur abundances in disk stars: A correlation with silicon
We have performed new determinations of sulphur and silicon abundances for a sample of 26 disk stars based on high-resolution, high signal-to-noise spectra. The results indicate a solar [S/Fe] for [Fe/H] > â0.3, below which [S/Fe] increases to ~0.25 dex at [Fe/H] = â1.0. We find that there is a good correlation between [S/H] and [Si/H], indicating the same nucleosynthetic origin of the two elements. It seems that the ratio of sulphur to silicon does not depend on metallicity for [Fe/H] > â1.0. The implications of these results on models for the nucleosynthesis of a-capture elements and the chemical evolution of the Galaxy are discussed. Based on observations carried out at National Astronomical Observatories (Xinglong, PR China)
Comparison of biochemical activities between high and low lipid-producing strains of Mucor circinelloides: An explanation for the high oleaginicity of strain WJ11
© 2015 Tang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The oleaginous fungus, Mucor circinelloides, is one of few fungi that produce high amounts of γ-linolenic acid (GLA); however, it usually only produces +:isocitrate dehydrogenase and NADP NADP+:isocitrate dehydrogenase, however, were 43% and 54%, respectively, lower in WJ11 than in CBS 277.49 and may retard the tricarboxylic acid cycle and thereby provide more substrate for ATP:citrate lyase (ACL) to produce acetyl-CoA. Also, the activities of ACL and fatty acid synthase in the high lipid-producing strain, WJ11, were 25% and 56%, respectively, greater than in strain CBS 277.49. These enzymes may therefore cooperatively regulate the fatty acid biosynthesis in these two strains.Peer Reviewe
Magnetic phase diagrams of the Kagome staircase compound Co3V2O8
At zero magnetic field, a series of five phase transitions occur in Co3V2O8.
The Neel temperature, TN=11.4 K, is followed by four additional phase changes
at T1=8.9 K, T2=7.0 K, T3=6.9 K, and T4=6.2 K. The different phases are
distinguished by the commensurability of the b-component of its spin density
wave vector. We investigate the stability of these various phases under
magnetic fields through dielectric constant and magnetic susceptibility
anomalies. The field-temperature phase diagram of Co3V2O8 is completely
resolved. The complexity of the phase diagram results from the competition of
different magnetic states with almost equal ground state energies due to
competing exchange interactions and frustration.Comment: Proceedings of the 2007 Conference on Strongly Correlated Electron
Systems, 2 pages, 2 figure
Two Energy Release Processes for CMEs: MHD Catastrophe and Magnetic Reconnection
It remains an open question how magnetic energy is rapidly released in the
solar corona so as to create solar explosions such as solar flares and coronal
mass ejections (CMEs). Recent studies have confirmed that a system consisting
of a flux rope embedded in a background field exhibits a catastrophic behavior,
and the energy threshold at the catastrophic point may exceed the associated
open field energy. The accumulated free energy in the corona is abruptly
released when the catastrophe takes place, and it probably serves as the main
means of energy release for CMEs at least in the initial phase. Such a release
proceeds via an ideal MHD process in contrast with nonideal ones such as
magnetic reconnection. The catastrophe results in a sudden formation of
electric current sheets, which naturally provide proper sites for fast magnetic
reconnection. The reconnection may be identified with a solar flare associated
with the CME on one hand, and produces a further acceleration of the CME on the
other. On this basis, several preliminary suggestions are made for future
observational investigations, especially with the proposed KuaFu satellites, on
the roles of the MHD catastrophe and magnetic reconnection in the magnetic
energy release associated with CMEs and flares.Comment: 7 pages, 4 figures, Adv. Spa. Res., in press
A tunable radiation source by coupling laser-plasma-generated electrons to a periodic structure
Near-infrared radiation around 1000 nm generated from the interaction of a high-density MeV electron beam, obtained by impinging an intense ultrashort laser pulse on a solid target, with a metal grating is observed experimentally. Theoretical modeling and particle-in-cell simulation suggest that the radiation is caused by the Smith-Purcell mechanism. The results here indicate that tunable terahertz radiation with tens GV=m ïŹeld strength can be achieved by using appropriate grating parameter
Identification of a candidate gene for Rc-D1, a locus controlling red coleoptile colour in wheat
Red coleoptile is an easily observed agronomic trait of wheat and has been extensively studied. However, the molecular mechanism of this trait has not yet been revealed. In this study, the MYB gene TaMYB-D1 was isolated from the wheat cultivar âGy115â, which possesses red coleoptiles. This gene resided at the short arm of the homoelogous group 7 chromosomes. TaMYB-D1 was the only gene expressed in the coleoptiles of âGy115â and was not expressed in âOpataâ and âCSâ, which have uncoloured coleoptiles. Phylogenetic analysis placed TaMYB-D1 very close to ZmC1 and other MYB proteins regulating anthocyanin biosynthesis. The encoded protein of TaMYB-D1 had an integrated DNA binding domain of 102 amino acids and a transcription domain with 42 amino acids, similar to the structure of ZmC1. Transient expression analysis in onion epidermal cells showed that TaMYB-D1 was located at the plant nucleus, which suggested its role as a transcription factor. The expression of TaMYB-D1 was accompanied with the expression of TaDFR and anthocyanin biosynthesis in the development of the coleoptile of âGy115â. Transient expression analysis showed that only TaMYB-D1 induced a few âOpataâ coleoptile cells to synthesize anthocyanin in light, and the gene also induced a colour change to red in many cells with the help of ZmR. All of these results suggested TaMYB-D1 as the candidate gene for the red coleoptile trait of âGy115â
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