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Vasile Muntean Radu Crisan Daniela Paşca Stefan Kiss Mihail Drăgan-Bularda 《International Journal of Salt Lake Research》1996,5(1):35-44
Sediments of 56 salt lakes from Romania were studied enzymologically. The following 7 enzymatic and nonenzymatic catalytic activities have been measured: phosphatase, H2O2-splitting in nonautoclaved (catalase) and autoclaved samples, TTC reduction in nonautoclaved (dehydrogenase) and autoclaved samples, without or with glucose addition. A formula is proposed for the evaluation of the enzymatic potential of salt lake sediments or other habitats. A hierarchy of the studied lakes has been established on the basis of the enzymatic potential of their sediments expressed as enzymatic indicator. 相似文献
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Continuous temperature logs to depths between 750 and 1400 m in the Transylvanian Basin, Romania, in many cases show temperature gradient variations with depth which cannot be explained by depth variations in thermal conductivity, topography and ground water flow. The only possible responsible agent seems to be past surface temperature variations. The temperature logs from nine boreholes have been interpreted individually and jointly by least squares inverse modelling with the surface temperature history and background heat flux as unknown parameters. All the temperature profiles are consistent with a temperature rise at the end of the last glaciation. The effects of borehole depth, of a wrong choice of thermal conductivity, and the level of uncorrelated random noise were examined using synthetic examples. 相似文献
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Crisan Demetrescu Maria Tumanian Venera Dobrica Constantin Mares Ileana Mares 《Pure and Applied Geophysics》2012,169(1-2):219-234
Temperature data from nine boreholes in the Carpathian orogen in Romania were used to obtain information on the ground surface temperature history (GSTH) in the last 250?years. The temperature measurements were taken with a thermistor probe (sensitivity in the 10 mK range) using the stop-and-go technique, at 10 m intervals, in the depth range of 20–580?m. The least squares inverse modelling approach of Tarantola and Valette (J Geophys 50:159–170, 1982) was used to infer the GSTH. Long-term air temperature records available from the Romanian weather station network were used as a comparison term for the first 100–150?years of the GSTH, and as a forcing function in a POM-SAT model that combines borehole temperature profiles (BTPs) and meteorological time series (surface air temperature, SAT) to produce information on the so-called pre-observational mean (POM). Results from a global circulation model for the Romanian area are incorporated in the discussion as well. 相似文献
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Crişan Demetrescu 《Pure and Applied Geophysics》1978,117(1-2):124-134
Heat flow values of 33–58 mW m–2 were found for the Transylvanian Depression, 45–57 mW m–2 for the crystalline nucleus of the Eastern Carpathians, and 70–120 mW m–2 for the Neogene volcanic area. Temperature-depth profile and some geophysical implications of the low values for the Transylvanian Depression are discussed, rendering evident clear-cut differences between this tectonic unit and other Noegene depressions. The heat flow values for the other two investigated tectonic units are usual ones for areas of their age.A preliminary map of the heat flow distribution over the Romanian territory is presented and its relation to other geophysical fields is discussed. A positive correlation was found between gravity and heat flow, and a negative one between crustal thickness and heat flow. A general conclusion could be drawn that the heat flow distribution over the Romanian territory seems to be governed by processes taking place in the upper mantle, rather than by the radioactive decay within the crust. 相似文献
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Gheorghe Demetrescu 《Studia Geophysica et Geodaetica》1958,2(3):293-295
Резюме Записи, относящиеся к глубоким землетрясениям, имевшим место с области Вранча, полученные на румынских станциях, свидетельствуют
о том, что между волнамиP иS существуют определенные импульсы, следующие друг за другом в довольно регулярных интервалах времени. Автор настоящей статьи
предлагает следующую интерпретацию.
Каждая волна, проходящая через поверхность разрыва, разделяется на две волны, из которой одна является продольной, а другая
поперечной, так что через каждый участок пути проходит продольная волна, обозначенная черезp, или волна поперечная, обозначенная черезs. При этих условиях и при предположении, что земная кора слагается лишь из гранитного и базальтового слоев, следует рассматривать
следующие волны:ppp≡P, pps, psp, pss, spp, sps, sss≡S. Эти волны могут быть использованы для определения толщины слоев земной коры.
Communication présentée à la 1ère Conférence séismologique de l’Académie Tchécosl. Sc. à Liblice, le 18 Mars 1957.
Adresse: Bucarest, rue Cuţitul de Argint 5, Roumanie. 相似文献
Communication présentée à la 1ère Conférence séismologique de l’Académie Tchécosl. Sc. à Liblice, le 18 Mars 1957.
Adresse: Bucarest, rue Cuţitul de Argint 5, Roumanie. 相似文献
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G. Atanasiu T. Neştianu D. Demetrescu M. Anghel 《Physics of the Earth and Planetary Interiors》1976,12(1):P11-P17
The paper presents some results concerning the secular variation of H, Z and F in Romania between 1958–1974. Curves of the variation of , Z and F at 31 repeat stations are given. The effect of solar activity on the horizontal component is separated and its characteristics discussed. For the interval 1969.5–1974.5 maps of the smoothed secular variation of H, Z and F are given, with isopores described by curves of second degree with respect to the geographical coordinates. 相似文献
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C. Demetrescu M. Andreescu M. Ene T. Neştianu 《Physics of the Earth and Planetary Interiors》1985,37(1):46-51
The variation of the H, Z, and T components of the geomagnetic field at repeat stations on Romanian territory between 1964 and 1981 is discussed in terms of internal secular and solar cycle related variations. Their geographical distribution is accounted for by the magnetic and electric structure of the interior of the Earth. The effects of magnetic and electromagnetic induction caused by the solar cycle related variation were evaluated. 相似文献
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V. Dobrica C. Demetrescu C. Boroneant G. Maris 《Journal of Atmospheric and Solar》2009,71(17-18):1727-1735
We analyze 100–150 years-long temperature and precipitation records from 14 meteorological stations in Romania, in connection with long-term trends in solar and geomagnetic activities. The comparison of solar (sunspot number) and geomagnetic (aa index) parameters with the mean air temperature over the Romanian territory, at interdecadal timescales, shows positive correlation coefficients, while the comparison with the mean precipitation shows negative correlation coefficients. The correlation of climatic parameters seems to be stronger for geomagnetic activity than for solar activity. The Romanian temperature series are examined in the context of other European stations and of averages on the European, northern hemisphere, and global scale, respectively. Long-term (interdecadal and centennial) trends and differences between local trends and average trends for larger areas are discussed. The study indicates that solar and geomagnetic activity effects are present on the 22-year Hale cycle timescale. The temperature variation on this timescale lags the solar/geomagnetic ones by 5–9 years. 相似文献