Coexisting Tetrahedrite–(Zn) and Sphalerite at the Teremki Gold-Ore Deposit (East Transbaikalia): Chemical Composition and Formation Conditions

Geology of Ore Deposits - Paragenetic associations of tetrahedrite-(Zn) and sphalerite are distinguished in the Teremki gold-ore deposit. The chemical composition of coexisting minerals of this...     

Causes and consequences of long-term groundwater overabstraction in Jordan

Hydrogeology Journal - In 2017, a comprehensive review of groundwater resources in Jordan was carried out for the first time since 1995. The change in groundwater levels between 1995 and 2017 was...     

On the Attractive Force of an Elliptical Gaussian Ring

Solar System Research - A numerical-analytical method for analyzing the orbital evolution of a planetary satellite under the influence of a perturbing body moving in an elliptical orbit is...     

Changes in the Period of Negative Superhumps of Type SU UMa Dwarf Novae. II. NY Her (2017 and 2020)

Astrophysics - Photometric studies of the type SU UMa dwarf nova NY Her were made during 2017 and 2020 at the Crimean Astrophysical Observatory and at the Sanglokh Observatory over a total of 77...     

Spatiotemporal analysis of COVID-19 risk in Guangdong Province based on population migration

Journal of Geographical Sciences - Population migration, especially population inflow from epidemic areas, is a key source of the risk related to the coronavirus disease 2019 (COVID-19) epidemic....     

Traces of Seismic Activity in Architectural Monuments in Derbent,Dagestan

Izvestiya, Atmospheric and Oceanic Physics - As a result of studies conducted in the city of Derbent, it is established that its monumental fortification structures erected at the end of the 560s...     

超临界态甲烷密度研究

超临界甲烷密度不仅是非常规天然气资源量计算与吸附能力测定的重要参数,同时也是衡量超临界甲烷扩散效率与溶解有机物能力的主要指标。通过对比分析各种气体状态方程的适用性,认为基于亥姆霍兹能量基本状态方程可以准确计算0~30 MPa、270~360 K条件下甲烷的密度。利用Microsoft Office Excel编写了甲烷密度的计算程序,与NIST （美国国家标准与技术研究院）商业软件计算结果相比,误差小于0.05%。分析了0~100 MPa、270~360 K范围内甲烷密度的变化规律。结果表明,甲烷密度随压力增大而增大,在低于30 MPa时增速较大且对温度的敏感性较强,高于30 MPa时增速逐渐变缓,且敏感性减弱。在煤层原位条件下随着埋深的增大,甲烷密度随温度升高而减小,随压力增大而增大;在温度与压力共同作用下,甲烷密度呈先增速不变、近似线性增加,后增速逐渐减小、凸曲线形增加的变化规律。游离态甲烷密度受温度的影响比吸附态甲烷小,是深部煤层气资源增量的主要贡献者。研究结果为深部煤层气赋存及其潜力预测提供了基础参数。      

On the Question of Calculating the Parameters of Vortices in the Near-Surface Atmosphere of Mars

Solar System Research - The paper is dedicated to the study of dust vortices on the Earth and Mars. The hydrodynamic similarity of convective vortices is considered, and the similarity criteria are...     

Artificial Beach as a Structure for Protecting a Seacoast from Storm Surge Impact (Based on the Example of the Eastern Gulf of Finland)

Oceanology - A model of an artificial beach is proposed for protecting a seacoast subjected to erosion under significant storm surge impact. The beach profile properties are based on the Dean...     

Mineral associations of the Lost Village and Lost City hydrothethermal fields in the North Atlantic

During the 50th cruise of R/V Akademik Mstislav Keldysh, on the south slope of the Atlantis massif (30°07′N; the Middle Atlantic Ridge), an inactive hydrothermal field named the Lost Village was discovered. This new field was formed of light carbonate rock and was located near the active Lost City hydrothermal field. The mineralogical associations of these fields were studied. A conclusion about the participation the ocean water in the changing of the carbonate composition of the inactive hydrothermal field was reached.