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A statistical analysis is used to determine the properties of metre-wavelength events which are associated with interplanetary type II bursts. It is found that the likelihood of an interplanetary type II burst is greatly increased if: (a) an associated metre-wavelength type II has a starting frequency less than 45 MHz; (b) a strong metre-wavelength continuum is present; (c) the type II contains herringbone fine structure; and (d) the metre-wavelength activity is accompanied by strong, long-lasting H and soft X-ray events.Visiting scientist at Division of Radiophysics, January 1983; previous address - NASA/Goddard Space Flight Center, Greenbelt, Maryland. 相似文献
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The device described in this paper, known as the traversing erosion beam, is believed to be the first to be designed specifically for measuring rates of downwearing of cohesive foreshores, such as clay shore platforms, under high‐energy wave conditions. It is primarily constructed of Flexlink Aluminium Structural System components and consists of a horizontal beam with a main leg and two further support legs. A sliding ‘dolly’ module is moved along the beam at precise intervals using a longitudinal scale as a reference. The topographic profile of the measurement surface is transferred to the dolly by a vertical sliding steel alloy rod, from which the relative height differences are measured by a separate engineer's digital height gauge placed on the dolly. The main leg of the device fits into a marine grade stainless steel box, which is deeply embedded into the foreshore or shore platform to act a permanent datum. The box is robust and can be expected to have a lifetime of at least a year, and possibly even five years or more. Sample data are provided from a clay shore platform at Warden Point in the Isle of Sheppey, Kent (UK), which demonstrate that the TEB can provide information on seasonal as well as annual rates of downwearing. The device has also been tested successfully on a peat and clay foreshore at Pett Level in Sussex and on a shore platform cut in glacial till at Easington, Yorkshire. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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E. W. Cliver S. W. Kahler H. V. Cane M. J. Koomen D. J. Michels R. A. Howard N. R. Sheeley Jr. 《Solar physics》1983,89(1):181-193
We use a variety of ground-based and satellite measurements to identify the source of the ground level event (GLE) beginning near 06∶30 UT on 21 August, 1979 as the 2B flare with maximum at ～06∶15 UT in McMath region 16218. This flare differed from previous GLE-associated flares in that it lacked a prominent impulsive phase, having a peak ～9 GHz burst flux density of only 27 sfu and a ?20 keV peak hard X-ray flux of ?3 × 10-6 ergs cm-2s-1. Also, McMath 16218 was magnetically less complex than the active regions in which previous cosmic-ray flares have occurred, containing essentially only a single sunspot with a rudimentary penumbra. The flare was associated with a high speed (?700 km s-1) mass ejection observed by the NRL white light coronagraph aboard P78-1 and a shock accelerated (SA) event observed by the low frequency radio astronomy experiment on ISEE-3. 相似文献
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Tropical air-sea interaction in general circulation models 总被引：10，自引：0，他引：10
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Thermo-plasticity of clays: An isotropic yield mechanism 总被引：5，自引：0，他引：5
Numerical modelling of the thermo-mechanical behaviour of soils is an important issue in the analysis of problems such as nuclear waste isolation or geothermal structures. The purpose of this paper is to present a new thermo-plastic mechanism for isotropic thermo-mechanical paths including thermal hardening. It is based on considerations of the thermal effect on void ratio. After a discussion of the experimental evidence, the formulation of the thermo-plastic yield mechanism is introduced. Typical features are analysed and the responses of the model discussed. The proposed model is validated on the basis of experimental results on two different clays. 相似文献
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We investigate the correlation of the occurrence of the herringbone phenomenon in type II solar radio bursts with various flare properties. We show that herringbone is strongly correlated with the intensity of the type II burst: whereas about 21% of all type II bursts show herringbone, about 60% of the most intense bursts contain herringbone. This fact can explain most of the correlations between herringbone and other properties such as intense type III bursts, type IV emission, and high type II starting frequencies. We also show that when this is taken into account, there is no need to postulate two classes of type II burst in order to explain why there appears to be a difference in herringbone occurrence between the set of type II bursts associated with the leading edges of coronal mass ejections, and those not so associated. We argue that the data are consistent with the idea that all coronal type II bursts are due to blast waves from flares. 相似文献
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The paper presents the results of an experimental study of thermal effects on the mechanical behaviour of a saturated clay. The study was performed on CM clay (Kaolin) using a temperature-controlled triaxial apparatus. Applied temperatures were between 22 and 90°C. A comprehensive experimental program was carried out, including: (i) triaxial shear tests at ambient and high temperatures for different initial overconsolidation ratios; (ii) consolidation tests at ambient and high temperatures; and (iii) drained thermal heating for different initial overconsolidation ratios. The obtained results provide observations concerning a wide scope of the thermo-mechanical behaviour of clays. Test results obtained at 90°C were compared with tests performed at ambient temperature. Based on these comparisons, thermal effects on a variety of features of behaviour are presented and discussed. Focus is made on: (i) induced thermal volume change during drained heating; (ii) experimental evidence of temperature influence on preconsolidation pressure and on compressibility index; (iii) thermal effects on shear strength and critical state; and (iv) thermal effects on elastic modulus. Thermal yielding is discussed and yield limit evolution with temperature is presented. The directions of the induced plastic strains are also discussed. Several remarks on the difference in the mechanical behaviour at ambient and high temperatures conclude the paper. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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混合海气耦合模式的研制和El Ni?o的预告试验 总被引：3，自引：0，他引：3
所使用的海气耦合模式是由COLA R15 AGCM和简单的CZ海洋模式耦合而成。使用该混合海气耦合模式完成了15次ENSO试验预报,预告和观测的Ni?o 3指数超前15个月的相关系数达0.6（在0.01有意义水平上该相关系数在统计上是有意义的）,超前一年半的Ni?o 3指数的预告误差大约为0.6～0.9℃。预告结果表明混合海气耦合模式具有预测ENSO的能力达15个月。最后,还讨论了该模式的优点和进一步改进的途径。 相似文献
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