One-dimensional hybrid approach to extensive air shower simulation     

T. Bergmann  R. Engel  D. Heck  N.N. Kalmykov  S. Ostapchenko  T. Pierog  T. Thouw  K. Werner 《Astroparticle Physics》2007,26(6):420-432

An efficient scheme for one-dimensional extensive air shower simulation and its implementation in the program conex are presented. Explicit Monte Carlo simulation of the high-energy part of hadronic and electro-magnetic cascades in the atmosphere is combined with a numeric solution of cascade equations for smaller energy sub-showers to obtain accurate shower predictions. The developed scheme allows us to calculate not only observables related to the number of particles (shower size) but also ionization energy deposit profiles which are needed for the interpretation of data of experiments employing the fluorescence light technique. We discuss in detail the basic algorithms developed and illustrate the power of the method. It is shown that Monte Carlo, numerical, and hybrid air shower calculations give consistent results which agree very well with those obtained within the corsika program.  相似文献   

Current climate change effects on the ground thermal regime in Central Yakutia     

Stepan Varlamov  Yuri Skachkov  Pavel Skryabin 《寒旱区科学》2014,6(4):0282-0292

The evolution of ground thermal state has been studied to assess impacts of current climatic warming on permafrost in Central Yakutia. The analysis of long-term data of regional weather stations has revealed one of the highest increasing trends in mean annual air temperature in northern Russia. A forecast of surface air temperature fluctuations has been made by applying a frequency analysis method. Monitoring of ground thermal conditions allows us to identify inter-annual and long-term variability among a wide range of natural conditions. Experimental research has indicated a long-term dynamics of ground thermal state evolution： ground temperatures at the depth of zero annual amplitude and seasonally thawed layer depth. Long-term variability of thaw depth shows near-zero to weak positive trends in small valleys in contrast to weak negative trends on slopes. With significant climatic warming, the thermal state of near-surface layers of permafrost demonstrates steadiness. Anthropogenic impacts on ground thermal regime in various terrain types have been qualitatively evaluated. Clear-cutting, ground cover stripping, and post-fire deforestation in inter-alas type terrains result in a significant increase of temperature and seasonal ground thaw depth, as well as adverse cryogenic processes. The dynamics of mean annual ground temperature in slash and burn sites have been evaluated in reference to stages of successive vegetation recovery.  相似文献   

Lithological-facial characteristics of the Upper Jurassic rocks of the Yetypur arch     

N. N. Petrakova  G. A. Kalmykov  N. I. Korobova 《Moscow University Geology Bulletin》2013,68(3):200-206

The Upper Jurassic Yu ₁ ¹ and Yu ₁ ² productive beds of one deposit from the Yetypur arch are characterized. The summarized scheme of sedimentation conditions before the Late Jurassic is constructed as a result of study of the drill core and geophysical log data. The northern, southern, and central parts of the deposit are occupied by a delta complex, beach sediments, and lagoon, overwater bar, and spit sediments, respectively. The scheme explains the dependence of the permeability on the open and effective porosity and the anomalously high oil debits of some wells.  相似文献   

Structure of colloid particles in groundwaters on the territory of the Mayak production association and its impact on the colloid transport of radionuclides in subsoil environments     

V. I. Malkovsky  Yu. P. Dikov  S. N. Kalmykov  M. I. Buleev 《Geochemistry International》2009,47(11):1100-1106

Colloid particles were examined in groundwaters sampled at the large contamination area of the subsoil environment at the Mayak production association in the Southern Urals. Colloid particles were separated from groundwater samples by ultrafiltration, and their composition and structure were analyzed by X-ray photoelectron spectroscopy (XPS) and Auger spectroscopy (AS). Our results indicate that the chemical composition of the particles significantly varies at their surface and along their radii, from the peripheries to the cores of the particles. The data are used to estimate the possibility of utilizing properties of colloid particles contained in groundwaters (the composition, structure, and zeta potential of such particles) to numerically simulate the spreading of radioactive contamination with groundwaters with regard to the colloid mode of radionuclide transport. It is demonstrated that, along with transmitting electron spectroscopy (TEM) coupled with X-ray microprobe analysis and electron diffraction, the XPS and AS techniques make it possible to obtain information on heterogeneity in the distribution and modes of occurrence of various elements in colloid particles.  相似文献   

Genesis of arsenic/fluoride-enriched soda water: A case study at Datong,northern China     

Yanxin Wang  Stepan L. Shvartsev  Chunli Su 《Applied Geochemistry》2009

The high As and F⁻ groundwaters from Datong Basin are mostly soda waters with a Na/(Cl+SO₄) (meq) ratio greater than unity, As and F⁻ up to 1550 μg/L and 10.4 mg/L, respectively, and with pH between 7.6 and 9.1. Geochemical modeling indicates that the waters are oversaturated with respect to calcite and clay minerals such as kaolinite, and undersaturated with respect to primary rock-forming minerals such as anorthite and albite. The water chemistry also is affected by evapotranspiration. The degree of evaporative enrichment is up to 85 in terms of Cl⁻. Results of the hydrogeochemical studies indicate that the occurrence of soda water at Datong is the result of incongruent dissolution of aluminosilicates at one stage of their interaction with groundwater when the water is oversaturated with respect to calcite and evapotranspiration-related salt accumulation is not too strong. Studying the genesis of soda waters provides new insights into mechanism of As and F⁻ enrichment in the aquifer system. Due to CaF₂ solubility control and OH⁻–F⁻ exchange reactions, F⁻ can be enriched in soda water. And the high pH condition of soda water favors As desorption from oxyhydroxide surfaces, thereby increasing the concentration of As in the aqueous phase.  相似文献   

Estimation of the heat-impact potential for stimulating the development of the deposits of the Bazhenov Formation according to the results of experimental studies     

A. A. Erofeev  A. A. Pachezhercev  I. A. Karpov  N. V. Morozov  A. G. Kalmykov  A. N. Cheremisin  E. V. Kozlova  A. Yu. Bychkov 《Moscow University Geology Bulletin》2017,72(5):339-348

The influence of temperature on rock samples of the Bazhenov Formation is shown. The samples underwent pyrolysis at 300–480°C, as well as in closed autoclaves in the presence of water under formation pressure. The temperature impact at 400°C resulted in a decrease in the S2 pyrolytic peak by 90–95% and almost complete formation of the generation potential of the rocks. Microtomographic studies of samples combined with raster electron microscopy revealed a correlation between the variable reservoir properties of the rocks. At 350°C, the rocks are characterized by a system of fractures; as a result of impacts, the porosity and permeability can increase from several to several tens of times. Our results will allow more precise modeling of the influence of tertiary processes on the rocks of the Bazhenov Formation in order to increase the final oil recovery of the bed.  相似文献   

A model of productive Miocene deposits,Odoptu area,Sea of Okhotsk     

A. L. Volkonskaya  I. N. Kerusov  A. I. Konyukhov  E. E. Karnyushina  O. V. Krylov  G. A. Kalmykov 《Moscow University Geology Bulletin》2017,72(5):349-354

The efficiency and abilities of the sequence-stratigraphic approach to the integrated interpretation of seismic and well data are considered based on the example of the Lower Nutovo subhorizon of the Odoptu area. The results of this study were used to build a sequence stratigraphic model, a curve of the relative sealevel changes, and a regional chronostratigraphic chart tied to the geochronologic timescale.  相似文献   

Radiophysical investigations of sea roughness (radiooceanography) at the Ukrainian Academy of Sciences     

Bass  F. Braude  S. Fuks  I. Kalmykov  A. Megn  A. Ostrovsky  I. Rosenberg  A. 《Oceanic Engineering, IEEE Journal of》1977,2(1):43-52

Experiments on the scattering of radio waves in the range 200 m to 3 cm from a rough sea surface are described. Amplitude, frequency, and space-time characteristics of scattered radio signals at different states of the sea surface are presented. It is shown that the problem of the short and medium wave scattering from the sea can be solved by the perturbance method. In this case the mechanism of scattering is of "resonant" character. The intensity of the backscatter signals is proportional to the density of the spatial spectrum on the half-length of the radio waves. The high frequency radio wave scattering is well described by a two-scale model of the scattering surface, "ripple on the large wave." The intensity of scattered radio signals is also proportional to the spectrum density of "ripples" whose length is approximately equal to half a radio wave. The effect of the large waves is to modulate the amplitude of a scattered radio signal and to broaden its frequency spectrum. Methods of solution of the reverse problem were considered. This allowed determination of parameters of sea roughness by characteristics of scattered radio signals. The principles of design of the corresponding equipment are described.  相似文献   

An Experimental Study of the Oil Production from Domanik Formation Rocks Under Hydrothermal Conditions     

A. V. Stennikov  I. A. Bugaev  A. G. Kalmykov  A. Yu. Bychkov  E. V. Kozlova  G. A. Kalmykov 《Moscow University Geology Bulletin》2018,73(1):60-65

The experimental results on synthetic oil production from rocks of the Domanik Formation under hydrothermal conditions are reported. The potential for oil-product extraction from the oil fractions of the rocks under a hydrothermal impact was up to 60 mg/g or 6.0 wt %. The injection of inorganic additives (sodium carbonate or silica gel) did not increase the oil-recovery factor. As well, the amount of the recoverable oil products directly depended on the mineral composition of the rocks. The relationship between the percentage of hydrocarbon yield and the mineral composition of the rocks was determined. Clay minerals and silica increased the yield of synthetic oil; carbonates, conversely, inhibit the process.  相似文献   

Selection of the data time interval for the prediction of maximum ozone concentrations     

Ju??KocijanEmail authorView author&#;s OrcID profile  Dejan?Gradi?ar  Martin?Stepan?i?  Marija?Zlata?Bo?nar  Bo?tjan?Gra?i?  Primo??Mlakar 《Stochastic Environmental Research and Risk Assessment (SERRA)》2018,32(6):1759-1770

This paper highlights the problem of step-length selection for the one-step-ahead prediction of ozone called the data time interval. This is done using a case study-based comparison of two approaches for predicting the maximum daily values of tropospheric ozone. The first approach is the 1-day-ahead prediction and the second is the prediction of the maximum values based on a multi-step-ahead iteration of 1-h predictions. Gaussian process modelling is utilised for this comparison. In particular, evolving Gaussian-process models are used that update on-line with the incoming measurement data. These sorts of models have been successfully used in the past for the prediction of ozone pollution. This paper contributes an assessment of the way that the maximum ozone values are predicted. A comparison of the daily maximum ozone values forecasted by a model based on 1-day-ahead predictions with those obtained by iterated 1-h-ahead predictions of the ozone with predictions at predetermined hours of the day is given. The forecast results are in favour of the on-line model based on hourly predictions when approaching closer to the real maximum values of ozone, and in favour of the daily predictions when they are made on a daily basis.  相似文献