共查询到20条相似文献，搜索用时 125 毫秒
1.
Summary The algorithm of iterative geophysical tomography is presented. The medium is approximated smoothly by means of B-splines. The tww-point problem of ray computation is solved with the aid of paraxial approximation. The parameters of the medium are obtained from the iterative algorithm of minimizing the quadratic form. Two numerical 2-D examples are given.
u¶rt; au umamuuu mauu. ¶rt;a annuuaa n nu nu -na. ma na aa a nu nu naaua annuauu. aam ¶rt; n a umamu aua uuauauu a¶rt;amu . am nu¶rt; ¶rt;a 2-D u nua.相似文献
2.
Summary Tests on the vertical vibrating table in the frequency range of70–110 Hz indicate that quartz gravity meters are10–100 times more sensitive at some frequencies than under low-frequency excitation. At high frequencies, the reading beam is at rest and deflected from the correct position. Slow fluctuations of amplitude and frequency near resonance could cause slow irregular motion of the beam with absence of low-frequency ground motion of sufficient intensity.
unmauaum a mua um¶rt; ¶rt;uana amm 70–110u mam, m a m ammaaum 10–100 a mum nu uamm au. u amm au u a¶rt;um n m mu m nu. ¶rt; auauu anum¶rt; u amm au uu aa m am uamm u ua ¶rt;a mmmm uamm au n ¶rt;mam umumu.相似文献
3.
Summary A two-dimensional flow model of an incompressible fluid with constant viscosity has been used to study the changes in the large-scale flow pattern (aspect ratio 4). Implications for convection in the Earth's mantle are discussed.
a ¶rt; mn uuu ua u¶rt;mu nm m unm ¶rt; uu uu mu ama¶rt;a. ¶rt;am mam ¶rt; uu amuu u.相似文献
4.
u¶rt;m n uu ¶rt;u m n u ma n¶rt;aa, nu m¶rt;u u ¶rt;uau. n nuu uu ¶rt;u m n ¶rt;a¶rt; nu NoNo VI, VII. u au u n m a
(x, H), ¶rt;auu an¶rt;u ¶rt;u m ¶rt; m¶rt; nu, u mua m nuu
(H), aamuu an¶rt;u m a mua ¶rt;¶rt; uu ¶rt;uua u a. u a ¶rt;u m
(x, H) amm ¶rt;uuu (u) a m¶rt; nu. m¶rt; u, auuu aau, om aamuam muau an¶rt;u ¶rt;u m, uu , n m u m nu aamuu a nmu, am ma a¶rt;am aa uu ¶rt;u m. aa u a¶rt;u n nu NoNo VI u VII u umuu ¶rt;a. mua m nu
(H) num m ¶rt;u amu aua u anam um, ¶rt;a amu ¶rt;aua u ¶rt;- nma (nu No VII). ma ¶rt; ¶rt; aua, maa numa nm m u numa nm ma¶rt;um, a unaa nuu umnmauu a¶rt;uu ¶rt;uau amu aua. 相似文献
5.
mam u¶rt;m uu aumuu a m n uamu ¶rt;u nmu umu ¶rt;ua a maum ¶rt;a amu u. a um naa nu nu naama umuu , au a um aumu m n aau umuu mau aum n. aam, m mum au ¶rt;-amu a ma mu aum u u n a aumu m n. 相似文献
6.
Summary A method of spectral analysis based on the prediction of the signal by means of AR parameters is proposed. The essence of this method ranks it between the classical methods of spectral analysis and the method of maximum entropy. For sufficiently high SNR its resolution is higher than that of the classical methods. The new method enables power and phase spectra of the signal to be determined, and provides a better determination of the power spectrum amplitude. than the method of maximum entropy. A regularization procedure is presented which abolished the instability of the prediction filter, obtained by the least-squares method.
¶rt; n nma aaua, a a n¶rt;aauu uaa n amu naam. mm n m ¶rt;au aumu auu m¶rt; nma aaua nuu u¶rt; u m¶rt;a aua mnuu. n a¶rt;am n aa nm n au auuu m¶rt;au nu aau n ¶rt;mam u mu ua . nm mu ua n¶rt;m a¶rt;, m¶rt; aua mnuu. muu m m¶rt;a aua mnuu n¶rt; n nma aaua nm n¶rt;m m a nm ua. aam n¶rt;aa uma um m¶rt; auu a¶rt;am, m unaa uau ¶rt; ¶rt;u mu am u.相似文献
7.
a auu uu nmama uau u¶rt;a u¶rt;mu (nn ¶rt;uu au m a) ua na ááa m a muau¶rt;¶rt;uaua uma. mumu mmmm uu aa nu¶rt;umu n au uu ma a u ma mu. 相似文献
8.
Summary The distribution of radioactive(Th, U, K), major and selected trace(Rb, Sr, Ba, Y, Zr, V, Cr, Ni) elements of granulites from the Saxonian Granulite Complex was studied. Similarly to the South Bohemian granulites, the Saxonian granulites can be divided according to the contents of their major and trace elements into two main groups, groupA containing mostly acid and subacid granulites (K
2
O>2.5%, SiO
2
>68%), and groupB containing mostly intermediate and basic granulites (K
2
O<2.5%, SiO
2
<68%). Statistically significant differences between groupsA andB were found for all major oxides and several trace elements(Rb, V, Cr, Ni). The Saxonian granulites follow the same calc-alkaline trend as the South Bohemian, granulitesA being placed mostly in the rhyolite field and granulitesB mostly in the dacite, andesite and basalt fields of this trend. The investigated granulites are characterized by a considerable scatter ofTh andU contents accompanied by very variableTh/U ratios; theTh andU concentrations of granulitesA are substantially lower than is usual for rocks of corresponding acidity.
¶rt;a an¶rt;u a¶rt;uamu(Th, U, K) u ua ¶rt;u(Rb, Sr, Ba, Y, Zr, V, Cr, Ni) m aum n¶rt;a aaum na. naa, m u¶rt;aum n uu aam n aaum u ¶rt;u am aua, u u uu. aum n u uu ma a¶rt;um ¶rt; ¶rt;nn; nnA nua¶rt;ama a au¶rt; u au¶rt;aum (K 2 O>2,5%, Si O 2 >68%), nnB ¶rt;u u aum (K 2 O<2,5%, SiO 2 <68%). ¶rt; muunnau mm mamumuu m au ¶rt; a u u ¶rt; m ¶rt;u m(Rb, V, Cr, Ni). auaum n¶rt;¶rt;m um- m¶rt; a u -uaum;aumA a¶rt;ma a uum n, uaumB a a ¶rt;aum, a¶rt;um u aam n m m¶rt;a. ¶rt;aum — u unnA — aamum uu ¶rt;au da¶rt;uamu mTh uU.相似文献
9.
Summary This paper discusses the disturbance produced in an infinite layer of non-homogeneous elastic material characterised by =0 n and =0n(n>0) where and are the density and shear modulus respectively of the material, due to periodic torsional force applied on the wall of a cylindrical hole in the layer. The variation of the displacement component with the radius vector is shown graphically and compared with the corresponding homogeneous case. 相似文献
10.
Summary The normal gravity field of Phobos defined by the sum a) of the gravitational potential of a homogeneous tri-axial ellipsoid representing the body of Phobos, b) of the potential of its centrifugal forces, c) of the constant part in the tidal-forming potential due to Mars, has been investigated. The radius-vector of the equipotential surface representing the normal model, as well as the gravity on it, have been derived. The long-term variations in the figure parameters and in gravity, due to the tidal evolution of the Mars—Phobos system, have been derived.
¶rt;m a n u mmu a, ¶rt;a a) nmuaa ¶rt;¶rt; m unu¶rt;a, n¶rt;ma m a, ) nmuaa m u, ) nm amu nuua nmuaa m aa. ¶rt; au a¶rt;ua-ma nmu, n¶rt;ma ¶rt;a a ¶rt;, u u u mmu a n¶rt;. auauu naam u u u u mmu, a nuu u um a—.相似文献
11.
¶rt;m uu maua anu, ¶rt;mu aau ¶rt;a u amuu a aumu¶rt;¶rt;uau ¶rt;uu ¶rt; u. a auum anu m u ¶rt;am au u mu u u¶rt;ua aum n. a nuu ¶rt; ¶rt;u naa, m u anmam u¶rt; . m uu u u ¶rt;uunauu a anmau mu . uu a u¶rt;, m m¶rt; a mu u m aum mm aumaua maum n ¶rt; u. 相似文献
12.
Günther Böhnecke 《Ocean Dynamics》1957,10(2):33-38
Zusammenfassung Folgende fünf Hauptprogramme für weltweite ozeanographische Untersuchungen werden im Internationalen Geophysikalischen Jahr 1957/58 durchgeführt: Mittlerer Wasserstand, Lange Wellen, Tiefenzirkulation, Mehr-Schiffe-Beobachtungen und Polarfront-Aufnahmen. Auf ihre Planung und Zielsetzung wird eingegangen. AnnÄhernd vierzig Nationen setzen etwa sechzig Forschungsschiffe, vierhundert Küstenpegel und vierzig Wellenmesser ein. Die Bundesrepublik Deutschland ist mit den beiden Forschungsschiffen Anton Dohrn und Gauss am Programm Polarfront-Aufnahmen im Nordatlantischen Ozean beteiligt.
Oceanographic operations in the International Geophysical Year (IGY)An outline of their plannings and aims
Summary The following five main programs of worldwide oceanographic investigations will be carried out during the International Geophysical Year 1957/58: Mean Sea Level, Long Waves, Deep Sea Circulation, Multiple Ships Measurements, and Polar Front Survey. Their planning and aims are outlined. Some forty nations will be using sixty research ships, four hundred coastal tide gauges and forty wave recorders. The German Federal Republic participates in the operations of the Polar Front Survey in the North Atlantic with their two research ships Anton Dohrn and Gauss.
Travaux océanographiques pendant l'Année Géophysique Internationale de 1957/58Une vue d'ensemble sur leurs projets et leurs buts
Résumé Pour l'Année Géophysique Internationale de 1957/58 cinq programmes principaux furent établis pour l'exécution de recherches océanographiques dans le monde entier. Ces programmes comporteront les opérations suivantes: «Enregistrements du Niveau moyen de la mer», «Enregistrements des Ondes longues», «Circulation de l'eau. profonde», «Observations par navires multiples de recherche» et «Relèvements du Front Polaire». Leurs projets et leurs buts sont exposés. D'environ quarante nations emploieront soixante navires de recherche, quatre cents échelles de marée et quarante enregistreurs de vagues. La République Fédérale d'Allemagne participera avec ses navires de recherche «Anton Dohrn» et «Gauss» aux opérations du «Levé océanographique du Front Polaire» (Polar Front Survey) dans l'Atlantique nord.相似文献
13.
Daniela Řezáčová Sněžana Todorova Рецензенm J Bednář 《Studia Geophysica et Geodaetica》1987,31(4):397-403
nuam aau ¶rt; amu a um ¶rt; ¶rt;a uauu. ¶rt; ¶rt;a, ¶rt;mu auumu m mnam u nu mum ¶rt;a, umam m ¶rt;u z aa n¶rt; uuu, a aau. u¶rt; auum ¶rt;au z naa m mauu ¶rt; amu, naam, m ¶rt;au ¶rt;z naa zauuam u amu ¶rt;.
Summary A formation of ice particles on artificial deposition INis described. INacting in dependence on the temperature and supersaturation over the ice are considered in the 1 D SSconvection cloud model with detailed microphysics including freezing. The limiting influence of the water vapour pressure upon the concentration of active INis shown resulting from the dependence of water vapour pressure on the ice particle concentration.相似文献
14.
Summary The tidal decrease in the Earth's heliocentric longitude generated by the Sun has been computed. It represents the increase in the length of year10–7 s per century. The resonant angular velocity of the Earth's rotation is approximately equal to the present Earth's mean motion, however, for the model used, i.e., considering the Sun as the point-mass.
u u zumu ¶rt;m u, a nuuau m a. ¶rt; mmmm uu ¶rt;u z¶rt;a10–7 a mmu. a za m au u nu aa ¶rt; ¶rt;uu u, u, ¶rt;a, umam ¶rt;a ¶rt;u m a.相似文献
15.
Summary The linearization approach is used to compute the travel times in inhomogeneous slightly anisotropic media. The basic formulae are outlined and their accuracy demonstrated in comparison with the exact solution based on the zero-order ray theory and the Backus formula (1965). The linearization is extended also to complex media with curved interfaces. The computer program for calculating travel times in 2D, inhomogeneous, slightly anisotropic, complex media is briefly described. The numerical results obtained for a realistic situation and various types of waves are presented to enable the effects of anisotropy and the effects of inhomogeneity on the resulting travel times to be compared.
na uauua n¶rt;¶rt; ¶rt; ama¶rt;aa , anmau aaumn ¶rt;a. ¶rt; u n¶rt; au m u n muu nuuuu u m¶rt; aa (1965). a uauua n¶rt;¶rt; ¶rt; a ¶rt; uuuauau a¶rt;a. am nuaa uuma naa ¶rt; ama¶rt;a ¶rt; ¶rt;. u mam ¶rt; a mun ¶rt;am m um m aumnuu u m ¶rt;¶rt;mu a a anmau .相似文献
16.
Summary The magnetic susceptibility of quartz single crystals is diamagnetic (–14×10
–6
in SI units) and exhibits only very small anisotropy (mostly less than 1%); thus the susceptibility of the quartz matrix in quartzite can be regarded as virtually isotropic. Owing to the influence of the negative and isotropic susceptibility of the quartz matrix, the degree of anisotropy of quartzite, as inferred from model calculations, is higher than that of the ferrimagnetic fraction. This influence is very strong if the mean susceptibility of quartzite is in the vicinity of zero.
uma aa m ¶rt;uaaumu (nuuum–14 × 10 –6 um ) u a aumnuu ( 1%). m aum, m nuuum a a auma m m numa namuu umn. amamu ¶rt;uau ¶rt;m, m n nuu uu muam u umn nuuumu a a mn aumnmu auma , mn aumnmu aum auu. m uu au m¶rt;a, ¶rt;a ¶rt;a nuuum ua .相似文献
17.
Summary The accuracy of wave field extrapolation is studied with respect to the discretization of field data and integral extrapolator. Assuming a far-field approximation of the Rayleigh-Sommerfeld solution for a two-dimensional scalar wave equation, the minimum and the maximum transmitted frequency are expressed as functions of the sampling intervals t, x, and the half-width x0 and angle a of the migration aperture. The theoretical limitation of the transmitted frequency band is tested on numerical examples.
aamuam mm manuu auumu m ¶rt;umuauu n u uma manu nama. ¶rt; u uma u -¶rt;a ¶rt; ¶rt; a au, ¶rt; nuuuu ¶rt;a n mu ¶rt; uua u aua n¶rt;aa amm a uu m a -nmam ¶rt;umuauu t u , nuu 0 u a a uau anm. mu n¶rt;u amm ¶rt;uanaa mmua a u nua.相似文献
18.
Summary The dependence of Pn-wave velocities on the heat flow, temperature at the crustmantle boundary and the thickness of the Earth's crust in Europe was investigated in relation to the problem of lateral inhomogeneities in the upper mantle. A map was constructed of the distribution of Pn-wave velocities on the territory of Europe. The relations these investigations yielded, were compared with the results of laboratory experiments and all the results are discussed from the physical point of view. The conclusion drawn is that that temperature and pressure effect provide a sufficient explanation of the observed regional changes of Pn-wave velocities for the European continent.
auum ¶rt;auu mu n¶rt; ¶rt; nmu uua (Pn) u mn nm, mnam a nmu amuu u m a mumuu n a u¶rt;aa u numa ¶rt;¶rt;m amuu. mumuu n a maa a uu m Pn- a nmu uua. u¶rt;u umam ¶rt;a mama aam u¶rt;au uuu m n¶rt; amuu u u ¶rt;au u mnam mmmm mama n¶rt;aa am. ¶rt;a ¶rt;, m ua uu m Pn- a n mum ¶rt;mam um uuu mnam u ¶rt;au a nmu uua.相似文献
19.
Jaroslav Kubík Reviewer A. Janáčková Reviewer V. Červený 《Studia Geophysica et Geodaetica》1988,32(3):287-299
Summary The dependence between Pn-wave velocities and the surface heat flow, temperature at the core-mantl boundary and thickness of the Earth's crust for continents (Europe, Asia, North America and Australia) was investigated statistically in connection with the problem of lateral inhomogeneities in the upper mantle. The relations obtained were compared with those determined under laboratory conditions. The conclusion is that temperature and pressure effects may provide additional explanations of the regional variations of Pn-wave velocities observed in most continents.
auum ¶rt;auu mu n¶rt; a nmu uua(Pn ), nm mn nm, mnam a u m mum a u¶rt;aa u n uuuma ¶rt;¶rt;m mu Pn. nua ¶rt;a mama aam u¶rt;au nu m n¶rt; amuu u u ¶rt;au u mnam a¶rt;um mmmuu mamau n¶rt;aa am. am ¶rt;, m ua uu m Pn- ¶rt; amu muma n¶rt;m auu m¶rt;uauu u a nmu muua.相似文献
20.
Summary Using the annual values of the indices of solar and geomagnetic activity for the period 1868–1976, the basic values characterizing the cycle as a whole were determined for the 11-year cycles nos 11–20, (Tab. 1). High values of the coefficients of correlation were found for some pairs of characteristic values of the same and different kinds, given in Tab. 2, which can be utilized for long-term predictions of geomagnetic activity.
a auu¶rt;u au u¶rt; uaum amumu muu 1868–1976 n¶rt; ¶rt; 11-mu u 11–20 naam aamuu u a (a. 1). u au uuma uu ¶rt; m na naam ¶rt;ua u ¶rt;ua ¶rt;a (a. 2), m m amu nuu nu ¶rt; nuauuaum amumu.相似文献