Energy cascades in the upper ocean     

Ray Q. Lin Scott Chubb 《中国海洋湖沼学报》2006,24(3):225-235

1 INTRODUCTION Wave-wave interactions play a key role in the evolution of the dynamics of upper ocean phenomena. Even though they conserve total wave energy, these interactions cause energy cascades to occur in which wave-energy is transferred at the surf…  相似文献   

The effect of differential refraction on wave propagation in rotating pulsar magnetospheres     

D. Fussell  Q. Luo 《Monthly notices of the Royal Astronomical Society》2004,349(3):1019-1026

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Vertical vibration of an elastic strip footing on saturated soil     

Y. Q. Cai  Y. M. Cheng  S. K. Alfred Au  C. J. Xu  X. H. Ma 《国际地质力学数值与分析法杂志》2008,32(5):493-508

Based on Biot's dynamic coupled equations, the vertical vibration of an elastic strip footing on the surface of saturated soil is studied. Utilizing the Fourier transform, the governing dynamic differential equations for saturated poroelastic medium are solved. Considering the mixed boundary value conditions at the bottom of the foundation, a pair of dual integral equations about the vertical vibration of an elastic strip footing is derived, which can be converted to a set of linear equations by means of infinite series of orthogonal functions. The relation between the dynamic compliance coefficients and the dimensionless frequency tends to be gentle with decreasing footing rigidity, while the dimensionless frequency has only small effect on the dynamic compliance coefficients. When the dynamic permeability is large, its effect on the dynamic compliance coefficients should be taken into consideration. Furthermore, the dynamic compliance coefficients are found to be not sensitive to Poisson's ratio of the soil for footing on saturated soil. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Finite element analyses of layered visco‐elastic system under vertical circular loading     

Q. Xu  M. S. Rahman 《国际地质力学数值与分析法杂志》2008,32(8):897-913

Analyses for the response of a linear visco‐elastic system subjected to axi‐symmetric vertical circular loading are presented. Hankel transforms with respect to the radial spatial coordinate are used to reduce the three‐dimensional problem to that involving only a single spatial dimension, which is then discretized using the finite element method. Three techniques are employed to handle the time factor in the visco‐elastic material: (i) direct time integration; (ii) Fourier transforms; and (iii) Laplace transforms. These methods are compared and evaluated through their numerical results. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

On Both the Time Histories of the 0.511 MeV Line and 2.223 MeV Line from the X4.8 Flare of 23 July 2002 Observed with Rhessi     

Gan  W.Q. 《Solar physics》2004,219(2):279-287

High-spectral-resolution measurements of the 2.223 MeV neutron capture line and the 0.511 MeV positron-electron annihilation line have been made with the Reuven Ramaty High-Energy Solar Spectroscopic Imager during the X4.8 flare of 23 July 2002. We have tried to explain both the time histories of the 2.223 MeV line and the 0.511 MeV line, adopting a power-law spectrum of accelerated ions. The results show that with a power-law spectral index of 3.52, the calculational time histories can roughly reproduce the observations. An improved fit between the calculated 2.223 MeV line and the observed 2.223 MeV line can be achieved if we allow the spectrum of accelerated ions to vary with time.  相似文献   

An Improved Method to Derive the Lower Energy Cutoff of non-Thermal Electrons From Hard x-Rays of Solar Flares     

Gan  W.Q.  Li  Y.P.  Chang  J.  Tiernan  James M. 《Solar physics》2002,207(1):137-147

By changing a dimensionless calculation to a dimensional one, introducing a more accurate bremsstrahlung cross section, and using a more reasonable fitting energy range, we have recalculated the hard X-ray bremsstrahlung produced by a beam of power-law electrons with a lower energy cutoff (E _c). The method to deduce E _c from the hard X-ray spectral observations has therefore been refined in comparison with our previous one. The universality of this method has been clarified and discussed. We have applied this improved method to the 54 BATSE/Compton Gamma Ray Observatory (CGRO) hard X-ray events. It was found that about 44% of sample hard X-ray spectra can be directly explained by a beam of power-law electrons with a lower energy cutoff. The value of E _c, varying from 45 keV to 97 keV, is on average 60 keV. Another 44% of sample hard X-ray spectra might be explained by a beam of power-law electrons with the energy cutoff lower than 45 keV, which is however beyond the availability of BATSE/CGRO. Still another 11% sample hard X-ray spectra cannot be explained by a beam of power-law electrons with a lower energy cutoff. These results, based on the lower energy resolution data, however, should be compared in the future with that based on a higher energy resolution data, like the data from HESSI.  相似文献   

The INT Photometric Hα Survey of the Northern Galactic Plane (IPHAS)     

Janet E. Drew  R. Greimel  M. J. Irwin  A. Aungwerojwit  M. J. Barlow  R. L. M. Corradi  J. J. Drake  B. T. Gänsicke  P. Groot  A. Hales  E. C. Hopewell  J. Irwin  C. Knigge  P. Leisy  D. J. Lennon  A. Mampaso  M. R. W. Masheder  M. Matsuura  L. Morales-Rueda  R. A. H. Morris  Q. A. Parker  S. Phillipps  P. Rodriguez-Gil  G. Roelofs  I. Skillen  J. L. Sokoloski  D. Steeghs  Y. C. Unruh  K. Viironen  J. S. Vink  N. A. Walton  A. Witham  N. Wright  A. A. Zijlstra  A. Zurita 《Monthly notices of the Royal Astronomical Society》2005,362(3):753-776

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Colour equations for UK Schmidt Telescope Tech-Pan film exposures     

D. H. Morgan  Q. A. Parker 《Monthly notices of the Royal Astronomical Society》2005,360(1):360-363

Kodak Technical Pan (Tech-Pan) film is a standard panchromatic emulsion that was used at the UK 1.2-m Schmidt Telescope (UKST) for a variety of broad-band exposures between 1992 and 2003. However, despite its versatility and frequent use, no formal presentation of its colour-term stability has been provided. A sample of 32 short-exposure Tech-Pan films was specifically acquired in five wavebands with a view to establishing the photometric relationships between Tech-Pan and the equivalent glass-based emulsions previously used. These films have been measured using the SuperCOSMOS measuring machine and the data reduced to provide the appropriate quantitative information. New colour terms relating these measurements to the Cousins photoelectric system are presented. They are shown to be stable, reproducible, generally small and similar to colour terms previously derived for the older emulsions on glass that Tech-Pan effectively replaced. These results give confidence in the use of Tech-Pan photometry from on-line UKST legacy survey archives.  相似文献   

Synthesis of Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>-loaded porous carbons developed from rice husk for removal of arsenate from aqueous solution     

S. Luo  M.-N. Shen  F. Wang  Q.-R. Zeng  J.-H. Shao  J.-D. Gu 《International Journal of Environmental Science and Technology》2016,13(4):1137-1148

A simple one-step synthetic approach using rice husk has been developed to prepare magnetic Fe₃O₄-loaded porous carbons composite (MRH) for removal of arsenate (As(V)). The characteristics of adsorbent were evaluated by transmission electron microscope, scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller analysis, and thermogravimetric analysis. On account of the combined advantages of rice husk carbons and Fe₃O₄ nanoparticles, the synthesized MRH composites showed excellent adsorption efficiency for aqueous As(V). The removal of As(V) by the MRH was studied as a function of contact time, initial concentration of As(V), and media pH. The adsorption kinetics of As(V) exhibited a rapid sorption dynamics by a pseudo-second-order kinetic model, implying the mechanism of chemisorption. The adsorption data of As(V) were fitted well to the Langmuir isotherm model, and the maximum uptake amount (q _m ) was calculated as 4.33 mg g^?1. The successive regeneration and reuse studies showed that the MRH kept the sorption efficiencies over five cycles. The obtained results demonstrate that the MRH can be utilized as an efficient and low-cost adsorbent for removal of As(V) from aqueous solutions.  相似文献   

Mitigation of multipath effect in GNSS short baseline positioning by the multipath hemispherical map   总被引：4，自引：2，他引：2  

D. Dong  M. Wang  W. Chen  Z. Zeng  L. Song  Q. Zhang  M. Cai  Y. Cheng  J. Lv 《Journal of Geodesy》2016,90(3):255-262

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