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71.
Izvestiya, Atmospheric and Oceanic Physics - A coupled Earth’s thermosohere-ionosphere global dynamics model (for altitudes of 90–500 km) is presented. This model is based on a...  相似文献   
72.

This paper focuses on the shrinkage behavior of soil specimens involving sand, kaolinite, and kaolinite/sand mixtures subjected to desiccation under controlled conditions. Both, free and restrained shrinkage conditions are studied. The experiments show that pure soils do not curl upon unrestrained shrinkage; however, (under the same conditions) kaolinite/sand mixtures exhibited a marked curling. Furthermore, the mixture with the higher sand content broke through the middle of the sample after displaying a significant curling. Soils subjected to restricted shrinkage developed cracks with slight curling. To simulate the observed behavior, a mechanical model able to reproduce the detachment of the soil sample from the mold is proposed in this work and implemented in a fully coupled hydro-mechanical finite-element code. It is concluded that suction and differential shrinkage are key factors influencing the curling behavior of soils. The proposed framework was able to satisfactorily explain and reproduce the different stages and features of soil behavior observed in the experiments.

  相似文献   
73.
Izvestiya, Atmospheric and Oceanic Physics - The interannual–multidecadal variability of the temperature and depth of the upper mixed layer (UML) in the North Atlantic (NA) is analyzed on the...  相似文献   
74.
Oceanology - A new approach has been applied to studying marine sedimentation using dispersed sedimentary material in sediment traps compared to the surface layer of bottom sediments. Based on...  相似文献   
75.
Doklady Earth Sciences - An isotope–geochemical study was performed on the waters of Abrosimov and Stepovoi bays along the southeastern coasts of the Novaya Zemlya Archipelago. The waters...  相似文献   
76.
Chelpanov  A. A.  Kobanov  N. I. 《Astronomy Reports》2020,64(4):363-368
Astronomy Reports - We applied a new approach to measure the time delays of magnetohydrodynamic waves propagating in the solar atmosphere. A small flare in the flare region of the chromosphere...  相似文献   
77.

The results of the first polarimetric measurements of near-Earth asteroid 2014 JO25 and comet 41P/Tuttle-Giacobini-Kresák performed on April 19, 2017, with a CCD sensor at the prime focus (f/3.85) of the 2.6-m Shajn Telescope of the Crimean Astrophysical Observatory in the R filter are reported. The degree of linear polarization of the asteroid is P = 2.69 ± 0.44% at a phase angle of 55.6°, which is typical of an S-type asteroid. Its geometric albedo is ρv ≈ 0.2. A digital filter applied to the direct image of the comet reveals a jet and a tail directed toward the Sun (PA = 45.1°) and away from it (PA = 241.2°), respectively, in the coma. The maximum degree of linear polarization in the near-nucleus region of the comet is 18% at a phase angle of 69.8°. The polarization decreases to 16.2–10.7% in coma regions with a radius of 865–4856 km. Various factors affecting the maximum degree of polarization and the polarization-degree distribution over the coma are discussed.

  相似文献   
78.
Bhavya  P. S.  Min  Jun-Oh  Kim  Min-Seob  Jang  Hyo Keun  Kim  Kwanwoo  Kang  Jae Joong  Lee  Jae Hyung  Lee  Dabin  Jo  Naeun  Kim  Myung Joon  Kim  Yejin  Lee  Junbeom  Lee  Chang Hwa  Bae  Hyeonji  Yoo  Hyeju  Park  Sanghoon  Yun  Mi Sun  Lee  Sang Heon 《Ocean Science Journal》2019,54(4):515-528
Ocean Science Journal - Investigations on marine N2 fixation have gained momentum since 1960s with eventual establishments of relevant methodologies to identify species involved and quantify the...  相似文献   
79.
Izvestiya, Atmospheric and Oceanic Physics - The technique for constructing the spatial distribution of maximum aerosol optical depth (MAOD) has been used to estimate the optically dense haze...  相似文献   
80.
Stable water isotopes δ18O and δ2H are used to investigate precipitation trends and storm dynamics to advance knowledge of precipitation patterns in a warming world. Herein, δ18O and δ2H were used to determine the relationship between extratropical cyclonic precipitation and local meteoric water lines (LMWLs) in the eastern Ohio Valley and the eastern United States. Precipitation volume weighted and unweighted central Ohio LMWLs, created with samples collected during 2012–2018, showed that temperature had the greatest effect on precipitation isotopic composition. HYSPLIT back trajectory modelling showed that precipitation was primarily derived from a mid-continental moisture source. Remnants of major hurricanes were collected as extratropical precipitation during the 2012–2018 sampling period in central Ohio. Extratropical precipitation samples were not significantly different from the samples that created the central Ohio LMWL. Six additional LMWLs were derived from United States Geological Survey (USGS) Atmospheric Integrated Research Monitoring Network (AIRMoN) samples collected in Pennsylvania, Delaware, Tennessee, Vermont, New Hampshire, and Oxford, Ohio. Meteoric water lines describing published samples from Superstorm Sandy, plotted with these AIRMoN LMWLs, showed isotopic composition of Superstorm Sandy precipitation was commonly more depleted than the average isotopic composition at the mid-latitude locations. Meteoric water lines describing the Superstorm Sandy precipitation were not significantly different in slope from LMWLs generated within 300 km of the USGS AIRMoN site. This finding, which was observed across the eastern Ohio Valley and eastern United States, demonstrated a consistent precipitation δ2H–δ18O relationship for extratropical cyclonic and non-cyclonic events. This work also facilitates the analysis of storm development based on the relationship between extratropical event signature and the LMWL. Analysis of extratropical precipitation in relation to LMWLs along storm tracks allows for stronger development of precipitation models and understanding of which climatic and atmospheric factors determine the isotopic composition of precipitation.  相似文献   
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