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A Rossby vortex was used to simulate the travelling of a large-scale magnetic structure across the equator. This process is reflected in the drift of the longitudinally averaged vertical component of the magnetic field and in the formation of distinct rotation periods of the nonaxisymmetric components in different latitude belts similar to the ones revealed from experimental data. 相似文献
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In the traditional axisymmetric models of the 11-year solar cycle, oscillations of the magnetic fields appear in the background of nonoscillating (over time scale considered) turbulent velocity fields and differential rotation. In this paper, an alternative approach is developed: The excitation of magnetic oscillations with the 22-year period is the consequence of hydrodynamic oscillations with the 11-year period. In the excitation of hydrodynamic oscillations, two processes taking place in high latitudes near the interface between the convective and radiative zones play a key role. One is forcing of the westerly zonal flow, the conditions for which are due to deformation of the interfacial surface. The other process is the excitation of a shear instability of zonal flow as a consequence of a strong radial gradient of angular velocity. The development of a shear instability at some stage brings about the disruption of the forcing of differential rotation. In the first (hydrodynamic) part of the paper, the dynamics of axisymmetric flows near the bottom of the convection zone is numerically simulated. Forcing of differential rotation having velocity shear in latitude and the existence of solutions in the form of torsional waves with the 11-year oscillation period are shown. In the second part the dynamics of the magnetic field is studied. The most pronounced peculiarities of the solutions are the existence of forced oscillations with the 22-year period and the drift of the toroidal magnetic field component from the mid latitudes to the equator. In high and low latitudes after cycle maximum, the toroidal component is of opposite sign in accordance with observations. In the third part, the transport of momentum from the bottom of the convection zone to the outer surface by virtue of diffusivity is considered. The existence of some sources of differential rotation in the convection zone is not implied. A qualitative correspondence of the differential rotation profile in the bulk of the convection zone and on its outer surface to experimental data is shown. The time correspondence between torsional and magnetic oscillations is also in accordance with observations. 相似文献
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Synthesized sphalerite solid solutions (FexZn1−xS) in the range 0 < x < 0.5 have been studied with the use of Raman spectroscopy. The main objective of these experiments was to learn how the iron content of sphalerite affects the Raman spectra. Raman intensities over the whole range of concentrations suggest a structure change in the rather narrow region of mole fractions of FeS between 0.15 and 0.25. Analysis of literature data as well as our own results on Raman scattering and X-ray powder diffraction suggests the observed phenomena might be due to a change in the percolation state of the crystal lattice. The ratio of intensities of some Raman lines can be, in principle, used for the compositional analysis of sphalerite. 相似文献
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Genrietta A. Pospelova Elżbieta Król Galina M. Levkovskaya Jadwiga Kruczyk Magdalena Kądziałko-Hofmokl Sergey A. Kulakov 《Acta Geophysica》2007,55(4):619-639
The paper presents the results of experimental rock-magnetic, paleomagnetic and palynologic study of Paleolithic sediments
sampled along two profiles in the Akhshtyrskaya cave, situated in the vicinity of Black Sea shore. In the upper part of profiles,
some magnetite was observed; in the middle and lower parts, strongly oxidized non-stoichiometric magnetite and hematite prevail.
Thin maghemite covers on the surface of fine magnetite grains are present in the majority of specimens. Natural remanence
has one characteristic component (CHRM), mostly of chemical origin, although in few specimens containing magnetite it may
be sedimentary. Directions of CHRM obtained by standard paleomagnetic methods revealed anomalous pattern only in layer 3/2,
which is slightly older than the overlying layer 3/1 whose age was established as (35±2)×103 years BP by the U-Th method. This suggests that this paleomagnetic anomaly (PMA) can be correlated with Kargapolovo excursion
dated on about (45−39)×103 years BP. In the remaining overlying and underlying layers, directions of CHRM are grouped around the present geomagnetic
field. Depth distributions of scalar magnetic parameters generally coincide with the lithological division of the profiles.
Palynologic study revealed the presence of 22 pollen zones. Five thermomers separated with colder periods were found in the
middle and lower parts of profile. The non-magnetite composition of magnetic fraction of the majority of studied sediments
— oxidized nonstoichiometric magnetite and hematite — resulted in the lack of correlations between paleoclimatic and scalar
magnetic characteristics. 相似文献
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The new retail trade and services and their emerging location pattern in St. Petersburg 总被引:1,自引:0,他引:1
The system of factors affecting the spatial distribution of the retail trade and service establishments has changed dramatically since socialist times. The administrative regulation lost its almost complete dominance and turned into one of the market forces. In contrast, the impact of the urban environment under very free market conditions substantially increased. We show the main directions of this influence. Two generalized indicators that we use describe macro trends in the development of the spatial system of retail trade and services. One of them, which we call the urban morphology, is of a concentric effect, another – transportation pattern – adds the sectoral component to the retail trade and services geography. Five systems of spatial attractions differently affect the distribution of different branches. 相似文献
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KULAKOV A P QIU Shan-wen MIASNIKOV E A WANG Xi-kui TASHCHI S M ZHAO Hua-chang SONG Chang-chun 《中国地理科学(英文版)》2000,10(4):348-355
1GIGANTICRING-MORPHOSTRUCTURESOFAMUR-SONGHUA-HUANGHELINEAMENT(ASHL)Thereareaseriesofgiganticring-morphostructure(RM)alongthemarginofcontinentwithdiameterfrom1-2to3-4thousandkilometers.ASHLcrossthenextmega-RMontheeasternmarginofAsia:Amur,Korean,EastChinaandtheSeaofOkhotsk.TheAmurmega-RMismorethan2500kmindiameterandcoversthewholebasinoftheAmurRiveraswellasseriesofsmallbasinsconnectedwiththeSeasofOkhotskandJapan.Theconformaldistributionofthe“steps”ofthicknessear… 相似文献
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Aleskerova Anna Kubryakov Arseny Stanichny Sergey Medvedeva Alessia Plotnikov Evgeniy Mizyuk Artem Verzhevskaia Liudmila 《Ocean Dynamics》2021,71(6):655-677
Ocean Dynamics - Long-term arrays of satellite optical measurements of Landsat-5,7,8 and Sentinel-2 were used to describe the characteristics of submesoscale eddy (SE) dynamics in different parts... 相似文献