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21.
The structure of the nematodes communities has been studied in the sediments on two sites located outside and under the layer
ofAhnfeltia tobuchiensis (Kanno and Matsubara 1932; Makijenko 1970). Bottom sediments at the stations were represented by sands with a different degree
of silting. Specific structure of nematodes at the stations was significantly different under the similar environmental conditions
(water depth, dissolved oxygen saturation, salinity, temperature of the bottom layer and organic carbon content inside of
the sediment). Nematodes dominated (75.7 %) in meiobenthos community under the layer of A.tobuchiensis where concentration of silt particles was 12 %. Representatives of the family Comesomatidae were dominant. Low index of species
diversity and high Simpson domination index were detected in this community. Under a layer ofA. tobuchiensis with the thickness of 30 cm concentration of the silt particles was 5.39 %; nematodes density was low and made 32.1 % of
the general density of meiobenthos. Species of the families Xyalidae and Monoposthiidae were dominant. Outside of A.tobuchiensis, field percentage of silt particles was minimal (3.1 %) and representatives of families Cyatholaimidae and Axonolaimidae
dominated. The specific structure of nematodes in this type of the ground is characterized by high index of species diversity
and low level of domination. 相似文献
22.
Rimma G. Motenko 《冰川冻土》2004,26(Z1):56-59
The results of studying of thermal properties of oil contaminated disturbed and undisturbed soils, group composition of oil and moisture phase structures contented in these soils are considered in this paper. The thermal properties for oil contaminated soils of undisturbed addition after 6 years of oil transformation and for soils of disturbed addition and artificial pollution are compared. And the influence of addition on thermal properties of soils was revealed. 相似文献
23.
Marina G. Persova Yuri G. Soloveichik Denis V. Vagin Dmitry S. Kiselev Alexander M. Grif Yulia I. Koshkina Anastasia P. Sivenkova 《Geophysical Prospecting》2020,68(7):2217-2253
We propose the approach to 3D inversion of airborne electromagnetic data, which is intended for discovering subvertical bodies overlapped by essentially inhomogeneous conductive layers. The approach is based on the geometric inversion in which a geoelectrical medium is parameterized with the use of block structures. During the inversion, the coordinates of the borders between the blocks and the rows of the blocks as well as resistivities inside them are determined. In order to solve the forward problem of the airborne electromagnetic survey, we use the non-conforming optimized mesh with the hexahedral cells, which enables us to reduce the number of degrees of freedom and smoothly approximate the curved borders of a geological medium. For a more reliable discovery of subvertical objects, we propose to carry out 3D inversions at several rotations of block structures relative to the flight lines. The workability of this approach is demonstrated using the data which are synthesized for complex geoelectrical models with topography, inhomogeneous overlapping layers and target subvertical bodies oriented differently relative to the flight lines. The results of this investigation show that, in some way or other, the elongated subvertical object is discovered and its orientation (the direction of its long side) is defined at different rotations of block structures used in 3D inversions. However, the most accurate recovery of the subvertical object length is achieved when the direction of its long side almost coincides with the direction of one of the block structures axes. Thus, the block structures rotations allow not only more reliably discovering a target object in complex geoelectrical conditions, but also more exactly defining its orientation and length. 相似文献
24.
In May, 2007 we sank the remains of a Minke whale (Balaenoptera acutorostrata) in the East Sea, Peter the Great Bay, at 30 m of water near the coast of Big Pelis Island. In the present study we describe the nematode communities in sediments under the implanted whale carcass. Abundance of nematodes increased with the distance from the carcass. Dominant trophic group was non-selective deposit feeders. The highest values of indexes of a specific diversity and evenness were noted in sediments under the whale, while domination index occurred at the highest distance from the whale. The suggestion is made that the cause of low density of nematodes in sediments under the whale is an extreme increase in number of macrofaunal animals, and predation and food competition between macro- and meiofauna. The changes noted in nematode assemblages living in an implanted whale in shallow waters are similar to those in deep-sea assemblages. 相似文献
25.
MHD simulations are here applied to aid in the interpretation of three apparent cusp encounters by the Cluster 4 spacecraft in unusual places when the magnetosphere was under extreme solar wind and interplanetary magnetic field (IMF) conditions associated with the passage of magnetic clouds imbedded within fast ICMEs. At the time of each cusp encounter the IMF was very strong, generally northward in one case, generally equatorial in a second case, and generally southward in the third case. In the southward IMF case, the MHD models locate the origin of the cusp-like plasma by showing that the position of the spacecraft at the time of encounter was engulfed in a tongue of high-pressure plasma extending from the magnetopause into the magnetosphere. This tongue points to the northern-hemisphere cusp as the source of the feature. In the equatorial IMF case an elevated-pressure feature that apparently marked a cusp encounter in the computations coincided, however, with a passage in the solar wind of a dynamic pressure pulse, thus giving an alternative interpretation of the feature. However, Cluster data unambiguously identified the event as an encounter with magnetosheath-like plasma. Given that the Cluster observations classify the event as a true encounter with a cusp-like plasma feature (and not a compression event), the model simulations can be interpreted as identifying the origin of the feature to have been the northern-hemisphere cusp even though?—?and this is the interesting point?—?the observation point was in the southern hemisphere. In the northward IMF case, neither cusp (defined as a magnetic funnel linking the magnetopause to the Earth) was directly connected to the observation point. Instead, this encounter of magnetosheath-like plasma appears to be an instance of boundary-layer formation by means of the Song?–?Russell mechanism in which two-point magnetic reconnection entrains magnetosheath plasma on closed field lines when the IMF is northward. 相似文献
26.
The meridional heat transport in the ocean is computed according to the data of zonal sections of the World Ocean Circulation
Experiment made in the North Atlantic in 1992–1998. We perform the generalized analysis of the estimates of meridional heat
transport obtained by different authors by direct methods on the basis of the data of sections made between 7.5 and 48°N in
the second half of the last century. The meridional heat transport averaged over the entire period of observations attains
its maximum (1.38 ± 0.19 PW) in the Subtropical Atlantic. The meridional heat transport is characterized by fairly intense
seasonal variability. Its maximum (about 1.9 PW) is observed in the Subtropical Atlantic at the end of summer and its minimum
(about 0.8 PW) is attained at the end of winter. A significant trend toward the intensification of meridional heat transport
is revealed near 36°N in 1959–1993 (from 0.75 to 1.1 PW). This is an indication of the intensification of meridional oceanic
circulation in the North Atlantic.
Dedicated to the 75th birthday of N. A. Timofeev, Honored Scientist of the Ukraine, Doctor of Geographical Sciences
__________
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 1, pp. 45–58, January–February, 2007. 相似文献
27.
By using the data of a standard section made along 24.5°N in the Subtropical Atlantic within the framework of the World-Ocean-Circulation
Experiment, we compute the meridional heat transport. In agreement with the major part of published estimates obtained according
to the data of direct oceanographic measurements, it is approximately equal to 1.1 PW. The meridional heat transport along
24.5°N is caused mainly by the quasistationary meridional circulation with fairly stable structure. At the same time, we discovered
the intense seasonal variability of some components of the meridional heat transport. The contribution of eddy heat flows
to the integral transport is insignificant.
Dedicated to the jubilee of Prof. Viktorina Fedorovna Sukhovei
__________
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 1, pp. 3–15, January–February, 2006. 相似文献
28.
29.
Kamil M. Bulatov Pavel V. Zinin Yulia V. Mantrova Aleksey A. Bykov Maksim I. Gaponov Alexsandr S. Machikhin Ivan A. Troyan Igor B. Kutuza 《Comptes Rendus Geoscience》2019,351(2-3):286-294
In this report, we demonstrate that combining the laser heating system in a diamond anvil cell (LH-DAC) with a tandem acoustic-optical tunable filter (LH-DAC–TAOTF) allows for the simultaneous measurement of (a) the relative infrared (IR, 1070 nm) power distribution on a specimen surface in the DAC; (b) the temperature distribution under laser heating of a specimen under high-pressure in a DAC; it also (c) provides an opportunity to control the shape of the IR laser spot on the surface of the heated specimen. The effect of the π-shaper on the shape and the position of the focus of the IR laser beam on a specimen using a TAOTF is also presented. For a 10× long-working distance objective, the smallest diameter of the IR laser was found to be around 10 μm, when the focal plane coincides with that of the imaging optical system of LH-DAC. The highest diameter of the IR laser was shown to be 20 μm when the rim of the π-shaper was set at 3 μm. It is demonstrated also that the TAOFT not only permits to measure the two-dimensional (2-D) distribution of the IR laser power, but also allows for the alignment of the laser before each heating event at different pressures. 相似文献
30.
V. N. Eremeev A. N. Zhukov M. A. Krasheninnikova A. A. Sizov A. E. Chekhlan 《Doklady Earth Sciences》2012,443(1):357-360
Based on the conception of the cyclic (wave) nature of the changes in the circulation of the atmosphere of the Atlantic-European
sector (index of the North Atlantic oscillations) and surface temperature of the Black Sea on scales smaller or equal to the
century scale, anomalies of the winter surface temperature are analyzed. It is shown that in the phase of the maximum of the
presumably 60-year cycle of changes in the NAO index a negative anomaly of surface temperature forms and in the phase of minimum
of this scale of changes of NAO, there is a positive anomaly. Estimates of the possible thermal state of the surface of the
Black Sea during the phase of the expected minimum in 2011–2020 of the 60-year cycle (60-year wave) of the NAO index are made.
The possibility of a phase shift between changes in solar activity, the NAO index, and anomalies of temperature of the Black
Sea on the scales of cyclic (wave) processes larger than 100 years is considered. 相似文献