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991.
In this paper we study only the perturbation due to the deformation of the elastic mantle by a tidal body force. In a previous
publication (Getino and Ferrándiz, 1989a) we defined two canonical systems of variables - we gave them the names ofelastic variables of Euler and Andoyer respectively. Next, using them, we obtained the canonical expression of rotational kinetic
energy.
In the present paper, using the same variables, we build up the elastic energy which is produced by the deformation of the
elastic mantle. We show that the three termsm = 0, 1, 2 corresponding to the second order of the development in spherical harmonics of the perturbing potential, a tidal
potential, are of the same order of magnitude. In addition, the numerical integration for a particular Earth Model (Takeuchi's
Model 2) is performed, with the aim of obtaining a numerical estimate of the coefficients which intervene in both this energy
and the previously mentioned kinetic energy. 相似文献
992.
To calculate the Balmer, Paschen, and Brackett line intensities, we solved the statistical equilibrium equations for a twenty level plus continuum atom of hydrogen.From the temperature, ionization, and the first three level populations of the prominence models deduced in a previous work we have calculated the populations of the twenty bound levels and the integrated intensities corresponding to the series mentioned above. The method was also applied to the Heasley and Mihalas theoretical models.Since the Lyman series are optically thick, we have worked out two different options: (a) assume radiative balance in these lines and (b) correct the radiative rates by multiplying them with an integro-exponential function EI2 which depends on the line optical depth at the thread center. The first option is shown to be the more consistent.The integrated line intensities from the Balmer series have been compared with the observations and a clear difference was noted between quiescent and active prominences in the sense that the active prominence case can not be well fitted with the available models.To evaluate the influence of the pressure, the temperature, the thermal conduction coefficient and the turbulence, velocity on the spectrum we have compared the results from different models.From this study we conclude that only the lines arising from the lower levels up to 8–10 can give us information about the physical parameters that characterized the solar prominences since the intensities from the higher members of the series depend only on atomic properties because of the small departures from LTE of the upper levels involved.Member of the Carrera del Investigador, CONICET, Argentina. 相似文献
993.
In this article an approximate analytical integration is performed of the Hamiltonian corresponding to the rotational motion
of an Earth whose elastic mantle is deformed by rotation and lunisolar attraction, using Deprit's perturbation method for
the first order. Besides the usual terms, this Hamiltonian includes the perturbation of the kinetic energy and the elastic
energy produced with the deformation, as well as their causes, the tidal and the centrifugal potential; these new terms have
already been studied for the tidal deformation in previous articles (Getino and Ferrándiz, 1990a, 1990b). The effects of the
deformation due to the centrifugal potential are studied in this article, following the same method as that used for the tidal
deformation. Numerical tables of the periodic perturbations corresponding to the nutation in obliquity and longitude are obtained.
As for the secular effects, a theoretical value of 457 days is obtained for Chandler's period. 相似文献
994.
Andrés E. Piatti Ata Sarajedini Doug Geisler Eduardo Bica Juan J. Clariá 《Monthly notices of the Royal Astronomical Society》2002,329(3):556-566
We carried out Washington system photometry of the intermediate-age Large Magellanic Cloud (LMC) star clusters NGC 2155 and SL 896 (LW 480). We derive ages and metallicities from the T 1 versus colour–magnitude diagrams (CMDs). For the first time an age has been obtained for SL 896, . For NGC 2155 we derive . The two clusters basically define the lower age limit of the LMC age gap. In particular, NGC 2155 is confirmed as the oldest intermediate-age LMC cluster so far studied. The derived metallicities are and for NGC 2155 and SL 896, respectively. We also studied the CMDs of the surrounding fields, which have a dominant turn-off comparable to that of the clusters themselves, and similar metallicity, showing that one is dealing with an intermediate-age disc where clusters and field stars have the same origin. We inserted the present clusters in the LMC and Small Magellanic Cloud (SMC) age–metallicity relations, using a set of homogeneous determinations with the same method as in our previous studies, now totalling 15 LMC clusters and four SMC clusters, together with some additional values from the literature. The LMC and SMC age–metallicity relations appear to be remarkably complementary, since the SMC was actively star-forming during the LMC quiescent age gap epoch. 相似文献
995.
二次多项式方法在卫星影像纠正处理过程中已得到广泛应用。纠正影像的精度取决于控制点的数量与分布状况,根据经验,在一景卫片上一般选取25~30个均匀分布的控制点即可满足影像平面精度的要求。多景影像拼接涉及到无缝镶嵌问题;应用ERDAS IMAGINE将多景已纠影像拼接为一体,作为Photoshop的背景影像,应用Photoshop的图像编辑与处理功能修改存在误差的线状地物影像,可实现影像无缝镶嵌。评定纠正影像的平面精度一般采用3种方法:一是精度估算;二是对照参考图量测同名点误差、计算平面精度;三是测算接边精度。 相似文献
996.
997.
998.
Michael Pierce Terry Bridges Duncan A. Forbes Robert Proctor Michael A. Beasley Karl Gebhardt Favio Raul Faifer Juan Carlos Forte Stephen E. Zepf Ray Sharples David A. Hanes 《Monthly notices of the Royal Astronomical Society》2006,368(1):325-334
NGC 4649 (M60) is one of a handful of giant Virgo ellipticals. We have obtained Gemini/GMOS (Gemini North Multi-Object Spectrograph) spectra for 38 globular clusters (GCs) associated with this galaxy. Applying the multi-index χ2 minimization technique of Proctor and Sansom with the single stellar population models of Thomas, Maraston and Korn, we derive ages, metallicities and α-element abundance ratios. We find several young (2–3 Gyr old) supersolar metallicity GCs, while the majority are old (>10 Gyr), spanning a range of metallicities from solar to [Z/H]=−2 . At least two of these young GCs are at large projected radii of 17–20 kpc. The galaxy itself shows no obvious signs of a recent starburst, interaction or merger. A trend of decreasing α-element ratio with increasing metallicity is found. 相似文献
999.
1000.
C、N、S、Fe是地下水中控制氧化-还原反应的主要元素,淤泥是黏土的演化初期,淤泥演化为黏土过程中会影响含水层水量水质,可能会造成地下水污染;其中的水岩相互作用可以概化为C-N-S-Fe-H2O体系的相互作用。淤泥演化过程的实质是淤泥在压力的作用下孔隙度不断变小,逐渐固结成岩;淤泥内部不断发生生物地球化学反应,C-N-S-Fe-H2O体系驱动各种物质的形态结构不断发生改变,其中加压速率和加压模式会影响淤泥里的C、N、S、Fe重要组分固液相的转化。本研究运用自主研发设计的增压装置,探究在3种加压速率(0.04 MPa/12 h、0.04 MPa/24 h、0.04 MPa/36 h)和加压模式(0.040.02 MPa/12 h、0.04 MPa/12 h、0.040.06 MPa/12 h)的情况下,固体介质中C、N、S、Fe向孔隙水释放的规律。结果表明:(1)匀速加压速率越慢,加压初期溶解性有机碳(DOC)、 释放速率越快, 和Fe2+浓度变化增大;DOC、 、 、Fe2+释放总量越多。(2)不同的加压模式,加速加压(0.040.06 MPa/12 h)下 、Fe2+的浓度波动较大;DOC、 、 和Fe2+的总释放量为加速加压(0.040.06 MPa/12 h)大于匀速加压(0.04 MPa/12 h)。(3)加压过程中,DOC和 呈显著正相关,改变加压速率会改变DOC, 、 和Fe2+的相关性。本研究表明改变加压速率和加压模式会对DOC、 、 和Fe2+的释放速率、释放总量和C、N、S、Fe的转化造成影响,其本质为氧化-还原反应和水岩相互作用的强弱发生了变化;本研究为地质演化过程中压力导致的主要元素变化提供了新的认识,认识到了隔水层会影响含水层的水质和水量,为原生劣质地下水的成因和地下水污染防治提供了新思路。 相似文献