Early migmatites in the prograde metamorphism zone of gneisses in the northern domain of the Ladoga Region: U-Pb evidence based on monazite     

Sh. K. Baltybaev  O. A. Levchenkov  V. A. Glebovitsky  E. V. Kuz’mina  N. G. Rizvanova  A. F. Makeev  L. K. Levsky 《Doklady Earth Sciences》2008,420(1):589-591

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Physicomechanical properties of cryptocrystalline fluorite from the Suran deposit, southern Urals     

P. L. Smolyansky  M. Sh. Akchurin 《Geology of Ore Deposits》2008,50(7):629-633

Microhardness (H) and fracture toughness (K _1C) have been studied for the main varieties of shock-resistant cryptocrystalline fluorite, a natural ceramic widespread at the Suran deposit. Suran cryptocrystalline fluorite (SCF) is characterized by high fracture toughness (K _1C), which is 2–5 times higher than K _1C of common fluorite monocrystals. The relationship between K _1C and microhardness H is complex and nonlinear. The SCF varieties from the sellaite-fluorite orebody are distinguished by the highest K _1C = 1.9–2.3 MPa m^1/2, which exceeds K _1C = 0.84 MPa m^1/2 of porcelain-like fluorite from the main fluorite orebody. Qualitative and quantitative variations of structural point defects in the studied samples exert a much stronger effect on microhardness than on fracture toughness, which mainly depends on the size of crystallites, their mutual crystallographic orientation, and the structure of intergranular boundaries, i.e., on the parameters seemingly related to recrystallization and/or twinning of fluorite. In general, the nature of the Suran deposit of fluorite ceramic with unusual physicomechanical properties remains a geological puzzle in many respects.  相似文献   

Source parameters of the M_L 4.1 earthquake of November 08, 2006, southeast Beni-Suef, northern Egypt     

A. Badawy  A.K. Abdel-Fattah  Sh. M. Ali  W. Farid 《Journal of African Earth Sciences》2008,51(3):151-159

In the early morning hours on Wednesday November 08, 2006 at 04:32:10(GMT) a small earthquake of M_L 4.1 has occurred at southeast Beni-Suef, approximately 160 km SEE of Cairo, northern Egypt. The quake has been felt as far as Cairo and its surroundings while no casualties were reported. The instrumental epicentre is located at 28.57°N and 31.55°E. Seismic moment is 1.76 E14 Nm, corresponding to a moment magnitude M_w 3.5. Following a Brune model, the source radius is 0.3 km with an average dislocation of 1.8 cm and a 2.4 MPa stress drop. The source mechanism from a first motion fault plane solution shows a left-lateral strike-slip mechanism with a minor dip-slip component along fault NNW striking at 161°, dipping 52° to the west and rake −5°. Trend and plunging of the maximum and minimum principle axes P/T are 125°, 28°, 21°, and 23°, respectively. A comparison with the mechanism of the October, 1999 event shows similarities in faulting type and orientation of nodal planes.Eight small earthquakes (3.0  M_L < 5.0) were also recorded by the Egyptian National Seismological Network (ENSN) from the same region. We estimate the source parameters and fault mechanism solutions (FMS) for these earthquakes using displacement spectra and P-wave polarities, respectively. The obtained source parameters including seismic moments of 4.9 × 10¹²–5.04 × 10¹⁵ Nm, stress drops of 0.2–4.9 MPa and relative displacement of 0.1–9.1 cm. The azimuths of T-axes determined from FMS are oriented in NNE–SSW direction. This direction is consistent with the present-day stress field in Egypt and the last phase of stress field changes in the Late Pleistocene, as well as with recent GPS measurements.  相似文献   

Determination of Phosphate in Saudi Arabian Waters     

F. B. Salem  Sh. M. Al Ghannam 《洁净——土壤、空气、水》1991,19(3):267-273

The procedures for the determination of phosphate are based on the reduction of molybdophosphoric heteropoly acids using ascorbic acid. Measurements of the complex products formed with rhodamine B and chlorophenol red dyes and the reduced molybdophosphoric acid are made at 490 and 510 nm with molar absorptivities of 28571 and 20949 l/mol. cm with each dye, respectively. Phosphate could be determined in the concentration ranges of 0.44 to 1.21 and 0.44 to 1.32 μg/l PO₄-P with rhodamine B and chlorophenol red dyes, respectively. The results obtained are compared with those of molybdophosphoric acid with rhodamine B and chlorophenol red using stannous chloride as reducing agent. These procedures are used for the determination of phosphate in the Kingdom of Saudi Arabia.  相似文献   

Patterns of the isotopic composition of precipitation in time and space: data from the Israeli storm water collection program   总被引：3，自引：0，他引：3  

M. RINDSBERGER  Sh. JAFFE  Sh. RAHAMIM  J. R. GAT 《Tellus. Series B, Chemical and physical meteorology》1990,42(3):263-271

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Long-term changes in the number and temperature of hot days in Georgia under global warming     

E. Sh. Elizbarashvili  M. E. Elizbarashvili  N. B. Kutaladze  Sh. E. Elizbarashvili  N. Z. Chelidze 《Russian Meteorology and Hydrology》2017,42(10):665-670

Variations in the number of hot days, their frequency, intensity, and duration in Georgia are studied using observational data from 50 weather stations for the period of 1936-2013. The periods of the onset of hot days in the year and their maximum intensity in different physiographic conditions are identified. The zoning of Georgia was carried out according to the rate of changes in the number of hot days. The results enhance the understanding of climate change in Georgia under global warming conditions.  相似文献   

The limits of possible values of inclination of Mercury's equator     

Sh. T. Habibullin 《Earth, Moon, and Planets》1992,58(1):79-95

The method of estimation of the limits, containing the equator inclination of a celestial body, had been developed. In this method it is necessary to know the orbital elements and the mass of a celestial body. Another condition is that the axial rotation of a body should be in the resonance with its orbital motion. It has been found that the equator inclinations should have the values between 1 .7 and 2 .6 for Mercury and between 1 .0 and 1 .8 for the Moon. It also has been found that largest harmonics in Mercury's physical libration are the harmonics sin( – 3g), cos( – 3g), sin g and sin 2.  相似文献   

Fuzzy logic algorithms in the analysis of electrotelluric data with reference to monitoring of volcanic activity     

Sh. R. Bogoutdinov  S. M. Agayan  A. D. Gvishiani  E. M. Graeva  M. V. Rodkin  J. Zlotnicki  J. L. Le Mouél 《Izvestiya Physics of the Solid Earth》2007,43(7):597-609

The expert processing of monitoring data of large networks on hazardous natural phenomena becomes increasingly more complicated due to an increase in the initial data flow. An approach alternative to the visual recognition of signals is proposed. A number of recognition algorithms and results of their application to the analysis of geoelectric potential monitoring data are discussed. Data of monitoring La Fournaise Volcano (Réunion Island) obtained in the vicinity of the intense volcanic eruption of 1988 are used. The obtained results show that these algorithms are capable of recognizing anomalous segments of records and discriminating between several types of anomalies presumably associated with the effects of various physical factors (heavy atmospheric precipitation, hydrothermal processes, and so on). The algorithms proposed in this work can be used both for the automation of expert work in operating monitoring systems and in investigations aimed at the identification of typical morphologic sequences in time series of data of various origins.  相似文献   

Evolution of the Meyeri Thrust Zone of the Northern Ladoga Region (Republic of Karelia,Northwest Russia): PT Conditions for the Formation of Mineral Parageneses and Geodynamic Reconstructions     

Baltybaev  Sh. K.  Vivdich  E. S. 《Geotectonics》2021,55(4):502-515

Geotectonics - In our study we characterize the thermodynamic regimes in the thrust zone of the newly formed Paleoproterozoic continental crust of the Svecofennian mobile belt on the outskirts of...  相似文献   

循环伏安法测定硼氢根离子          下载免费PDF全文

陶松  房春晖  房艳  周永全  朱发岩  戈海文  许沙  陈巧玲 《盐湖研究》2012,20(3):32-36,42

主要用圆盘Au电极的电化学循环伏安法定量分析强碱性溶液中BH4-的浓度。实验采用三电极体系,工作电极为Au电极,参考电极为Hg/HgO电极,分别用铂、石墨作辅助电极,测定了在碱性体系中,不同浓度NaBH4溶液的循环伏安图,得到相应浓度下峰值电流值,并讨论了在同一浓度下扫描速度对BH4-氧化电流的影响。实验还测量了以镍电极、铂电极为工作电极时溶液的循环伏安图,并与Au电极结果做了对比。结果表明,BH4-在Au电极上活性最高,Au电极做工作电极的三电极体系测量BH4-离子浓度是一种简单、快速的方法,在测定范围内(10-4～10-2mol/L)线性关系良好。  相似文献