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151.
Piotr Lubiski Andrzej A. Zdziarski 《Monthly notices of the Royal Astronomical Society》2001,323(2):L37-L42
We study properties of Fe K lines of a large sample of Seyfert 1s observed by ASCA . Fits with power laws and Gaussian lines yield the average linewidth and equivalent width of 0.22±0.03 keV and 0.13±0.01 keV, respectively. Thus, the typical lines are weak and narrow. We then obtain the average line profile of all our spectra, and find it to consist of a narrow core and blue and red wings, with the red wing being much weaker than that of e.g. MCG −6-30-15. We obtain three average spectra of Seyferts grouped according to the hardness, and find the equivalent width of the core (originating in a remote medium) to be ≃50 eV in all three cases. The wings are well fitted by a broad line from a disc with strong relativistic effects. Its equivalent width correlates with the slope, increasing from ∼70 eV for the hardest spectrum to ∼120 eV for the softest one. The inner disc radius decreases correspondingly from ∼40 to ∼10 gravitational radii, and the fitted disc inclination is ∼45°. The obtained correlation between the slope and the strength of the broad Fe K line is found to be consistent with the previously found correlation of the slope and Compton reflection. 相似文献
152.
Piotr
roda Wojciech Czuba Marek Grad Aleksander Guterch Edward Gaczy
ski POLONAISE Working Group 《Tectonophysics》2002,360(1-4):169-185
This paper reports the results of 3-D tomographic modelling of crustal structure in the Trans European Suture Zone region (TESZ) of Poland, eastern Germany and Lithuania. The data are the product of a large-scale seismic experiment POLONAISE'97, which was carried out in 1997. This experiment was designed to provide some 3-D coverage. The TESZ forms the boundary between the Precambrian crustal terranes of the East European Craton (EEC) and the younger Phanerozoic terranes to the southwest. The 3-D results generally confirm the earth models derived by earlier 2-D analyses, but also add some important details as well as a 3-D perspective on the structure. The velocity model obtained shows substantial horizontal variations of crustal structure across the study area. Seismic modelling shows low (<6.1 km/s) velocities suggesting the presence of sedimentary rocks down to a depth of about 20 km in the Polish basin. The shape of the basin in the vicinity of the profile P4 shows significant asymmetry. Three-dimensional modelling also allowed tracing of horizontal irregularities of the basin shape as well as variations of the Moho depth not only along profiles, but also between them. The slice between P2 and P4 profiles shows about 10-km variations of the Moho over a 100-km interval. The crustal thickness varies from about 30 km in SW, beneath the Palaeozoic platform, to about 42 km beneath East European Craton in NE. High seismic velocities of about 6.6 km/s were found in the depth range 2–10 km, which coincides with K
trzyn anorthosite massif. The results of this 3-D seismic modelling of the POLONAISE'97 data will ultimately be supplemented by inversion of seismic data from previous experiments. 相似文献
153.
Jan Drzymala Andrzej Luszczkiewicz Piotr Simiczyjew 《International Journal of Mineral Processing》1983,10(4):289-296
Ilmenite from Polish magnetite-ilmenite ores has been floated with tall oil. Chemical and mineralogical analysis of the flotation products established that the ores containing hercynite are difficult to upgrade. For ore A (18.7% hercynite and 32.8% ilmenite) and ore B (9% hercynite and 41.3% ilmenite) poor concentrates containing much less than the required 45% TiO2 have been obtained. It has been found that the higher concentration of hercynite in the feed, the lower the grade of concentrates in respect to TiO2 is obtained. Ilmenite ore containing a minor amount of hercynite (ore C, 0.15% hercynite and 12.3 ilmenite) gives a good concentrate. By means of microscopic observation it was established that hercynite floats together with ilmenite in the rougher flotation but is partially depressed in the cleaning and scavenging flotation. 相似文献
154.
The determination of Fe, Mn, Ni, Pb, Cu, Co, Zn, Cd, Ca and Mg was carried out in the soft tissues and shells of Mytilus edulis and Cardium glaucum from Gdańsk Bay. This paper reports on the influence of size (age) on the metal concentration in molluscs. Both species-dependent variability and regional variations of metal concentrations in molluscs were observed. The correlation coefficients between the concentrations of metal in the soft tissues and shells were determined. The correlation coefficients between hard and soft parts metals were calculated for Mytilus edulis. 相似文献
155.
Seda Şalap-Ayça Piotr Jankowski Keith C Clarke Phaedon C Kyriakidis Atsushi Nara 《International journal of geographical information science》2018,32(4):637-662
The paper presents a computationally efficient meta-modeling approach to spatially explicit uncertainty and sensitivity analysis in a cellular automata (CA) urban growth and land-use simulation model. The uncertainty and sensitivity of the model parameters are approximated using a meta-modeling method called polynomial chaos expansion (PCE). The parameter uncertainty and sensitivity measures obtained with PCE are compared with traditional Monte Carlo simulation results. The meta-modeling approach was found to reduce the number of model simulations necessary to arrive at stable sensitivity estimates. The quality of the results is comparable to the full-order modeling approach, which is computationally costly. The study shows that the meta-modeling approach can significantly reduce the computational effort of carrying out spatially explicit uncertainty and sensitivity analysis in the application of spatio-temporal models. 相似文献
156.
157.
This report is a comment on two papers by Matese and Whitman (1989, 1992). We discuss here the applicability of uniform probability densities for the orbital parameters of the Oort cloud comets. 相似文献
158.
ABSTRACTRecent focus on sustainable urban development and livability has increased the demand for new data sourcing techniques to capture experiences and preferences of urban dwellers. At the same time, developments of geospatial technologies and social media have enabled new types of user-generated geographic information and spatially explicit online communication. As a result, new public participation GIS methods for engaging large groups of individuals have emerged. One such method is geo-questionnaire, an online questionnaire with mapping capabilities, which has been used to elicit geographic data in variety of topics and geographical contexts. This article presents two recent cases, in which geo-questionnaires have been used in Polish cities to obtain public input on quality of life and development preferences in local land use planning. The article evaluates participant recruitment methods focusing on sample representativeness, participant engagement, and data quality. Recruitment via social media was found to increase bias towards younger population. Paper questionnaires used along the online version provided for better representation of target population’s age structure, but did not reduce bias related to educational attainment. We discuss how these issues relate to data usability and generalizability in the context of digital divide, and suggest directions for future research. 相似文献
159.
The structure of bryozoan assemblages from two Arctic regions (East Greenland and West Spitsbergen shelf) was compared. Both areas are located at the same latitude and the samples were taken from similar depths; however, the regions differed in water temperature and oceanography. East Greenland, which has lower mean annual water temperatures, was found to be one third richer in taxa (86 species) than West Spitsbergen (59 species). Diversity (Shannon–Wiener index – H′) and abundance were also higher on average in East Greenland (e.g. H′ = 2.49) than West Spitsbergen (e.g. H′ = 2.12). However for species richness, diversity and abundance there were no significant statistical differences between means (ANOVA) from the two regions. In spite of these similarities the investigated assemblages differed to a large extent in both species composition and dominance structure. There were 55 species that occurred only in East Greenland and 28 species that were present only in West Spitsbergen. There was higher proportion of species with an Arctic distribution in East Greenland (46%) than in West Spitsbergen (24%). Observed dissimilarities were concluded to be due to different hydrological conditions between the two regions. 相似文献
160.
Patricia Roeser Nadine Dräger Dariusz Brykała Florian Ott Sylvia Pinkerneil Piotr Gierszewski Christin Lindemann Birgit Plessen Brian Brademann Michał Kaszubski Michał Fojutowski Markus J. Schwab Michał Słowiński Mirosław Błaszkiewicz Achim Brauer 《Boreas: An International Journal of Quaternary Research》2021,50(2):419-440
We revise the conceptual model of calcite varves and present, for the first time, a dual lake monitoring study in two alkaline lakes providing new insights into the seasonal sedimentation processes forming these varves. The study lakes, Tiefer See in NE Germany and Czechowskie in N Poland, have distinct morphology and bathymetry, and therefore, they are ideal to decipher local effects on seasonal deposition. The monitoring setup in both lakes is largely identical and includes instrumental observation of (i) meteorological parameters, (ii) chemical profiling of the lake water column including water sampling, and (iii) sediment trapping at both bi-weekly and monthly intervals. We then compare our monitoring data with varve micro-facies in the sediment record. One main finding is that calcite varves form complex laminae triplets rather than simple couplets as commonly thought. Sedimentation of varve sub-layers in both lakes is largely dependent on the lake mixing dynamics and results from the same seasonality, commencing with diatom blooms in spring turning into a pulse of calcite precipitation in summer and terminating with a re-suspension layer in autumn and winter, composed of calcite patches, plant fragments and benthic diatoms. Despite the common seasonal cycle, the share of each of these depositional phases in the total annual sediment yield is different between the lakes. In Lake Tiefer See calcite sedimentation has the highest yields, whereas in Lake Czechowskie, the so far underestimated re-suspension sub-layer dominates the sediment accumulation. Even in undisturbed varved sediments, re-suspended material becomes integrated in the sediment fabric and makes up an important share of calcite varves. Thus, while the biogeochemical lake cycle defines the varves’ autochthonous components and micro-facies, the physical setting plays an important role in determining the varve sub-layers’ proportion. 相似文献