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221.
ZHU Yulin 《《地质学报》英文版》2000,74(3):492-499
The Daiyunshan-Shiniushan volcanic depression in Fujian Province is situated in a volcanic belt of the southeast coastal area in China along the west Pacific Ocean. A new breakthrough has been made in the exploration of gold and silver ore deposits in recent years. The minerogenic series of the Daiyunshan-Shiniushan volcanic depression is discussed in this paper based on the analysis of major metallogenic types and factors. According to the study of enormous ore deposits and occurrences in the study area, two minerogenic series have been recognized: 1. Late Jurassic Au-Ag-Pb-Zn minerogenic series related to intermediate-acid, acid volcanic formations; 2. nonmetallic minerogenic series (pyrophyllite, alunite pearlite, andalusite, zeolite, corundum and so on) related to intermediate and acid volcanic formations. The division and study of the minerogenic series have revealed metallogenic and time-space distribution characteristics of the ore deposits in the volcanic belt of the southeast coastal area in Ch 相似文献
222.
Małgorzata Pisarska‐Jamroży Tomasz Zieliński 《Boreas: An International Journal of Quaternary Research》2014,43(2):330-348
The Drawa sandur, which is the largest, coarse‐grained sandur in Poland, dates from the Pomeranian phase of the Weichselian glaciation (c. 16 ka BP). Using Markov chain analysis we infer that five cycles and five rhythms occur in its proximal part. The cycles dominated by Gt and St lithofacies in the lower part of the sandur succession and by a GDm lithofacies in the upper part, are fining‐upward cycles deposited in braided channels during large ablation floods. Three groups of cycles are distinguished based on their genesis: (i) cycles due to channel‐sheet evolution during large floods; (ii) cycles due to braid‐bar development during initial and advanced diminishing of floods; and (iii) cycles developed in the thalweg or interbar channels. The succession as a whole forms a large‐scale coarsening‐up megacycle (‘sandur megacycle’) which corresponds to a phase of ice‐sheet advance. Because the cyclicity was evident from Markov chain analysis of the sedimentary succession, we suggest that this statistical tool is valuable for reconstruction of glacifluvial sedimentary conditions, particularly as it can shed new light on the palaeogeographical development of sandar. 相似文献
223.
224.
Winter weather conditions vs. air quality in Tricity,Poland 总被引:1,自引:1,他引:0
Jadwiga Nidzgorska-Lencewicz Małgorzata Czarnecka 《Theoretical and Applied Climatology》2015,119(3-4):611-627
225.
226.
Łukasz Stachnik Piotr Wałach Łukasz Uzarowicz Jacob C. Yde Zornitza Tosheva Dominika Wrońska-Wałach 《山地科学学报》2014,11(5):1097-1111
This study aims to determine the relationships between local meteorological conditions,proglacial river discharge and biogeochemical processes operating in a periglacial basin located in the Polar Ural mountain range, Russia. Fieldwork was conducted in the catchment of Obruchev Glacier(13 km2) during the summer peak flow period in 2008. River discharge was dominated by snowmelt and changed from 3300 l s-1 to less than 1000 l s-1. The mean daily air temperatures of stations situated in the mountain tundra and near Obruchev Glacier from July 11 th to August 1st 2008 were 14.4°C and 10.3°C, respectively. The glacial river had low total dissolved solids varying from 4.5 to 9 mg l-1 and coefficients of correlation between Na+ and Cl-, K+ and Cl-, as well as NH4+ and Cl- were 0.94, 0.90 and 0.84, respectively. Rainfall events affected the snowmelt initiation and provided an essential part of the discharge during the intense snowmelt period, which occurred from July 11 th to July 18 th 2008. Data showed that Na+ and K+ in the surface water derived from snowmelt rather than chemical weathering of silicates. Also, it was obtained that NO3- derived from the melting snowpack, whereas ammonification occurring under the snowpacks was the primary source for NH4+. 相似文献
227.
Six variations of multiplicative random cascade models for generating fine-resolution (i.e., 5-minute interval) rainfall time series were evaluated for rainfall in Wroclaw, Poland. Of these variations, one included a new beta-normal generator for a microcanonical cascade. This newly proposed model successfully reproduces the statistical behavior of local 5-minute rainfalls, in terms of intermittency as well as variability. In contrast, both the canonical cascade models with either constant or time-scaled parameters and a microcanonical cascade model with a beta generator substantially underestimate 5-minute maximum rainfall intensities. The canonical models also fail to properly reproduce the intermittency of the rainfall process across a range of timescales. New observations are also made concerning the histograms of the breakdown coefficients (BDC). The tendency of the BDC histograms to have values exactly equal to 0.5 is identified and explained by the quality of pluviograph records. Moreover, the hierarchical evolution of BDC histograms from beta-like for long time steps to beta-normal histograms for short time steps is observed for the first time. The potential advantage is shown of synthetic high resolution rainfall time series generated by the revised microcanonical model for use in hydrology, especially hydrodynamic modelling of urban drainage networks. 相似文献
228.
The main focus of this paper is calculation of the diameters of asteroids belonging to five families (Vesta, Eos, Eunomia, Koronis, and Themis). To do that, we used the HCM algorithm applied for a data set containing 292,003 numbered asteroids, and a numerical procedure for choosing the crucial parameter of the HCM, called “the cutting velocity” vcut. It was established with a precision as high as 1 m s?1. Thereafter, we used the WISE (Wide‐field Infrared Survey Explorer) catalog to set a range of albedo for the largest members of each family considered. The albedo data were supported by the data concerning color classification (SDSS MOC4). The asteroids with albedo out of this range were classified as interlopers and were therefore disqualified as family members. Sizes were calculated for the asteroids with albedo within the acceptable range. For the other asteroids (those chosen by means of the HCM, but with albedo not listed in the WISE), the value of albedo of the largest member of the family was adopted. Results are given in a set of figures showing the families on the planes (a, e), (a, i), (e, i). Diameters and volumes of the asteroids that are the individual members of a family were calculated on the basis of their known or assumed albedo and on their absolute magnitude. Volumes of the parent bodies of the families were found on the basis of the cumulative volume distribution of these families. We also studied the secular resonances of the family members. We have shown that the locations of members of the considered asteroid families are related to the lines of secular resonances z1, z2, and z3 with Saturn. 相似文献
229.
A. Olech P. R. Woniak C. Alard J. Kaluzny I. B. Thompson 《Monthly notices of the Royal Astronomical Society》1999,310(3):759-764
We present V -band light curves of 61 variables from the core of the globular cluster M5 obtained using a newly developed image subtraction method (ISM). Four of these variables were previously unknown. Only 26 variables were found in the same field using photometry obtained with dophot software. Fourier parameters of the ISM light curves have relative errors up to 11 times smaller than parameters measured from dophot photometry. We conclude that the new method is very promising for searching for variable stars in the cores of the globular clusters and gives very accurate relative photometry with quality comparable to photometry obtained by the Hubble Space Telescope . We also show that the variable V104 is not an eclipsing star as has been suggested, but is an RRc star showing non-radial pulsations. 相似文献
230.
Photometric detection of high proper motions in dense stellar fields using difference image analysis
The difference image analysis (DIA) of the images obtained by the Optical Gravitational Lensing Experiment (OGLE-II) revealed a peculiar artefact in the sample of stars proposed as variable by Woźniak in one of the Galactic bulge fields: the occurrence of pairs of candidate variables showing anti-correlated light curves monotonic over a period of 3 yr. This effect can be understood, quantified and related to the stellar proper motions. DIA photometry supplemented with a simple model offers an effective and easy way to detect high proper motion stars in very dense stellar fields, where conventional astrometric searches are extremely inefficient. 相似文献