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581.
本文推导出柱坐标系下含有粘性摩擦项的正压方程组。选取2005年台风麦莎登陆浙江过程中的8月6日15时的WRF(Weather Research and Forecasting)模式输出资料,利用数值差分方法对该正压方程组求特征波解,分析粘性摩擦对台风麦莎内部正压特征波动的影响。结果表明,重力惯性外波在粘性摩擦的影响下,最不稳定波的波数为45左右,波动在摩擦的影响下衰减,波动沿逆时针传播,在半径1000 km处,1波波速为47.43 m/s,在半径r>800 km的范围内,径向风分量扰动加大,辐合辐散运动增强;而摩擦影响下的涡旋Rossby波,2波最不稳定,波动增长率减小,在半径r=200 km处波动相速度为4.282~29.172 m/s,扰动涡度大值区范围减小,涡旋Rossby波的波动区域沿着径向向台风中心收缩。分析包含所有波动时,考虑摩擦后,最不稳定波数在45左右且波动衰减,1波波速在r=1000 km处(外螺旋雨带)为26.374 m/s;在半径r=200 km(内螺旋雨带)为5.275 m/s,考虑径向基本气流后,最不稳定波的波数保持不变,半径r=1000 km处的波速增加为30.324 m/s,r=200 km(内螺旋雨带)处波速为6.065 m/s,摩擦使得径向风分量扰动明显增大,辐合辐散运动加强。 相似文献
582.
An accessible model for interstellar OH/H2O maser associations is presented. It can be classified into radiative pumping model. It can close the dynamical cycle of H2O and OH species, and can give an interpretation on interstellar OH/H2O associations. A reasonable scheme for both regeneration and destruction of interstellar H2O and OH molecules is argued. Our model has overcome the defects of former radiative models, and is compatible with astronomical conditions. It is shown that the rotational population of H2O and OH in these regions is much less affected by collisions than by radiation. Some experiments have confirmed our proposal. 相似文献
583.
584.
L. Cayón A. J. Banday T. Jaffe H. K. Eriksen F. K. Hansen K. M. Gorski J. Jin 《Monthly notices of the Royal Astronomical Society》2006,369(2):598-602
Higher Criticism (HC) has been proposed by Donoho & Jin as an effective statistic to detect deviations from Gaussianity. Motivated by the success of the Bianchi VIIh model in addressing many of the anomalies observed in the Wilkinson Microwave Anisotropy Probe ( WMAP ) data (Jaffe et al.), we present calculations in real and in wavelet space of the HC statistic of the Bianchi-corrected WMAP first-year data. At the wavelet scale of 5°, the HC of the WMAP map drops from a value above the 99 per cent confidence level (c.l.) to a value below the 68 per cent CL when corrected by the Bianchi template. An important property of the HC statistic is its ability to locate the pixels that account for the deviation from Gaussianity. The analysis of the uncorrected WMAP data pointed to a cold spot in the Southern hemisphere, centred at l ∼ 209°, b ∼−57° . The HC of the Bianchi-corrected map indicates that this spot remains prominent, albeit at a level completely consistent with Gaussian statistics. Consequently, it is debatable how much emphasis should be placed on this residual feature, but we consider the effect of modestly increasing the scaling of the template. A factor of only 1.2 renders the spot indistinguishable from the background level, with no noticeable impact on the results published in Jaffe et al. for the low- l anomalies, large-scale power asymmetry or wavelet kurtosis. A trivial interpretation would be that the Bianchi template may require a small enhancement of power on scales corresponding to the wavelet scale of 5°. 相似文献
585.
1 IntroductionThroughoutthegeologicalhistory ,almostallthetectonicplateactivities,suchasearthquakes,volcaniceruption ,andmountainbuilding ,takeplaceatactiveplateboundaries.Forexample,approxi mately 90 percentoftheearthquakesoccuratactiveplateboundaries[1 - 4 ] ,andthehighestmountainsofTibetandAndesresultfromthecontinualcollisionbetweenIndiaandAsia ,NazcaandSouthAmericaplates,respectively .Aplateboundaryisafracturethatseparatesaplatefromanother;theneighboringplatesmoverelativetooneanotherin… 相似文献
586.
After nearly 20 years of construction,we have successfully solved a series of hydrologic sedimentaryand environment problems encountered during the construction of the big deep water harbour inLianyungang which can now accommodate ships of 50000 tonnage.With the economic development,the channel of 50000 tonnage will be built soon, and of 100000 tonnage is under planning. Theconstruction of the international container shipping hub at the harbour is being accelerated in anticipationof the opening of the second Eurasian land bridge.The future development of the harbour will givegreat impetus to the local economy of Lianyungang City and make it an international city. 相似文献
587.
588.
Zhong-Quan Qu Shuai Wang Cheng-Lin Xu XiaoYu Zhang Ming-Guo Sun Chun-Lan Jin National Astronomical Observatories/Yunnan Astronomical Observatory Chinese Academy of Sciences Kunming zqqu@vip.km.net Graduate School of the Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2005,5(4):426-432
We analyze the spectral line broadening of those magneto-sensitive lines in solar magnetized atmospheres. The broadening at the line wings is due to the increase of the effective width of energy levels involved in Zeeman splitting, and the broadening at the line core also originated in Zeeman splitting under the condition that the Zeeman components are mixed. Therefore, the magnetoinduced or Zeeman broadening take effects on the whole line. The observed Stokes parameter data in a sunspot and outside it acquired by Solar Stokes Spectrum Telescope (S3T) are analyzed for the demonstration of this mechanism, and the Zeeman broadening rates are calculated for FeI6302.5 under some assumptions. Our result shows that the broadening is increased as the magnetic field strength becomes stronger, but the rate of increase at the line core is decreased as the field strength increases, while the rate at the wing does not show such an obvious regularity. The broadening is more effective in the line core than in the wings. 相似文献
589.
We notice that the second kind of astronomical methanol maser with strong emission always coexists at both 6.7 GHz and 12.2 GHz and in association with compact H II regions and we are led to propose a new excitation mechanism —maser amplification of the 6.7 GHz maser wothout population inversion. We show that this mechanism is compatible with the astronomical conditions and that it and other mechanisms are not mutually exclusive, rather it may serve as a useful complement. 相似文献
590.
Chen Jin ling 《成都信息工程学院学报》1989,(2)
本文简单介绍了LVDT、相敏检波器和三角波发生器的工作原理及自行设计的一种实用的LVDT相敏检波读出电路。 相似文献