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991.
Poecilia reticulata PETERS (guppy) and the green alga Monoraphidium griffithii were used for testing of different fluorotensides. After the representation of the methods of investigation and the definition of criteria of toxicity the obtained results of investigation are discussed. In general, the toxicity of the four investigated fluorotensides to algae was lower than to fish. The anionic fluorotenside CF3—(CF2)n—CFH—COONa was an exception. In tables and diagrams the results are summarized. Finally, for the condition of the receiving-water biocenosis class “2” the respective still permissible matter concentrations are proposed. They vary between 0.05 and 0.2 mg/1. 相似文献
992.
Milan M. Ćirković 《Astrophysics and Space Science》2003,283(2):273-277
The existence of rotation signatures in damped Lyαabsorption systems represents a crucial test of the hypothesis that these features arise in disks of normal spiral galaxies. We apply the method for evaluating such signatures to the metal absorption lines in QSO 0528-250. In particular, the systemic redshift of the absorber is inferred from the recent detection of emission in the absorber by Möller and Warren. The kinematics of this absorber are particularly interesting because molecular hydrogen, the densest ISM component of the assumed foreground absorbing galaxy, is detected. Contrary to a recent claim, the method yields a satisfactory value for the assumed rotation velocity of the absorber. 相似文献
993.
S. Kida K. Niinuma S. Suzuki T. Tanaka R. Nakanura K. Takefuji N. Matsumura M. Kuniyoshi T. Daishido 《New Astronomy》2008,13(7):519-525
The Nasu Observatory, which is composed of eight 20 m elements, was constructed for observing radio transients over a wide field at 1400 MHz. We report on two radio transients detected in consecutive drift scanning observations at declination 32° over a period of about two months. One of the two transients, WJN J1039+3200, appeared at =10h39m40s±10s, δ=32°±0.4° on March 4, 2005, and the other one, WJN J0645+3200, appeared at =06h45m25s±10s, δ=32°±0.4° on March 24, 2005. Both exhibited flux densities in excess of 1 Jy, and the burst durations were up to two days. Since there are few examples of radio transients outside the Galactic plane, these are very important observations. We have previously reported on four radio transients with features that look like the two transients detected this time. Of these six WJN transients in total, five had a duration of up to two days, and one up to three days. Four of the transients were detected at high Galactic latitude of b > 30°. Counterparts of the six WJN transients included X-ray sources in four events and had a consistency of 66%. The consistency of γ-ray, PGC Galaxy, NVSS, and FIRST sources was concentrated at about 50%. We were not able to find any special features in the counterparts. The distribution was verified by making a log N–log S plot using data for the four previously detected transients and the new ones. As a result, the distribution of the radio transients that we observed might have an isotropic distribution not dependent on Galactic longitude and Galactic latitude. The detection probability was calculated based on the assumption of an isotropic distribution. The 2σ upper probability limit for detection of transients of 1000 mJy or more is 0.0049 [deg−2 yr−1]. We cannot yet identify these two radio transients, because their features are different from any radio bursts observed in the past. 相似文献
994.
M.A. Etheridge 《Tectonophysics》1975,25(1-2)
The microstructures and fabrics of naturally deformed orthopyroxenites from the Giles Complex, central Australia are described in some detail. Coarse grained enstatite is deformed and recrystallised where it is incorporated in planar gneissic (mylonite) zones which show a gradation in strain from their margins inwards. Deformation takes place by slip on (100) [001] to produce regular lattice bending and kinking, and recrystallisation takes place preferentially along grain boundaries and kink band boundaries (KBB's). The microstructures and preferred orientation of recrystallised grains along KBB's are interpreted in terms of possible nucleation mechanisms, and both bulge nucleation (Bailey and Hirsch, 1962) and subgrain coalescence (Hu, 1963) are likely contributors. Electron microprobe analyses have indicated a small compositional difference between new (recrystallised) and host (deformed) grains, which is related to the nucleation mechanism. The total preferred orientation patterns for host and new grains are discussed with special reference to previous measurements and interpretations. 相似文献
995.
In the first part of this study, a series of stress-controlled hollow cylinder cyclic torsional triaxial shear tests were conducted on loose to medium dense saturated samples of clean Toyoura sand to investigate its liquefaction behavior. A uniform cyclic sinusoidal loading at a 0.1 Hz frequency was applied to air-pluviated samples where confining pressure and relative density was varied. Cyclic shear stress–strain changes, the number of cycles to reach liquefaction and pore pressure variations were recorded. Results indicate that the liquefaction resistances of uniform sands are significantly affected by the method of sample preparation and initial conditions. 相似文献
996.
Reinforced concrete columns with insufficient transverse reinforcement and non‐seismic reinforcement details are vulnerable to brittle shear failure and to loss of axial load carrying capacity in the event of a strong earthquake. In this paper, a procedure is presented after examining the application of two macro models for displacement‐based analysis of reinforced concrete columns subjected to lateral loads. In the proposed model, lateral load‐deformation response of the column is simulated by estimating flexural and shear deformation components separately while considering their interaction and then combining these together according to a set of rules depending upon column's yield, flexural and shear strengths. In addition, lateral deformation caused by reinforcement slip in beam–column joint regions and buckling of compression bars are taken into account and considered in the analysis. Implementation of the proposed procedure produces satisfactory lateral load–displacement relationships, which are comparable with experimental data. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
997.
OA Bergstad ÅS Høines R Sarralde G Campanis M Gil F Ramil 《African Journal of Marine Science》2019,41(1):11-28
Most of the Southeast Atlantic Ocean is abyssal, and global bathymetries suggest that only ~3.2% of the areas beyond national jurisdiction (ABNJ; also known as the high seas, as defined in the United Nations Convention on the Law of the Sea [UNCLOS]) are shallower than 2 500 m. This study mapped bathymetry and characterised substrates in selected seamount summit areas, including several that have been or may become fishing areas. The southernmost location, the Schmitt-Ott Seamount, has exposed volcanic bedrock with surrounding flats covered by thin biogenic sediments and/or coral rubble that appears ancient. At Wüst, Vema, Valdivia and Ewing seamounts the basaltic base appears to be overlain by coral caps and other coral substrates (sheets, rubble). Adjacent summit plains have biogenic sediments of varying thickness. Vema has a flat, roughly circular summit, <100 m deep, with the shallowest point being a 22-m-deep summit knoll; the upper slopes have ancient coral framework, but the summit has a mixture of coralline and volcanic rock and coarse sediments, including extensive areas with coralline algae and kelp forests. Valdivia Bank is a 230-m-deep, flat, rocky area (~11 × 5 km), protruding steeply from the extensive multi-summit Valdivia subarea of the Walvis Ridge. The distribution of past fisheries in the Convention Area of the South East Atlantic Fisheries Organisation (SEAFO) was considered in relation to the new information on bathymetry and substrate. 相似文献
998.
Richard M. Smith 《The Professional geographer》1986,38(1):62-67
The most common goal when classing data for choropleth maps is to create homogeneous classes which contain similar data values. None of the four traditional data classing methods examined here (quartile, equal interval, standard deviation, and natural breaks) consistently generalized the experimental data sets into homogeneous classes. These methods were most accurate for data sets with specific distributional characteristics, but none classed all of any type of distribution accurately. Only the optimization method produced reliable and accurate results for all of the experimental data. 相似文献
999.
Differential energy spectra of low abundant elements between silicon and iron of energetic solar particles (SEP) in the August 4, 1972 event were measured in the energy region of 10 to 40 MeV amu–1 using rocket-borne Lexan detectors. The relative abundances of elements were determined and abundance enhancements, i.e., SEP/photospheric ratios, and their energy dependence were derived in 10–40 MeV amu–1 interval. It is found that there are four types of abundance enhancements as a function of energy as follows: (a) silicon, iron, and calcium show fairly strong energy dependence which decreases with increasing energy and at 20–40 MeV amu–1 reaches photospheric values; (b) in case of sulphur enhancement factors are independent of energy and the values are close to unity; (c) argon shows energy independent enhancements of about 3 to 4 in 10–40 MeV amu–1; (d) titanium and chromium show weakly energy-dependent, but very high abundance enhancement factor of about 10 to 40. These features are to be understood in terms of the atomic properties of these elements and on the physical conditions in the accelerating region. These are important not only for solar phenomena but also to gain insight into the abundance enhancements of cosmic-ray heavy nuclei.on leave from Tata Institute of Fundamental Research, Bombay, India. 相似文献
1000.
Using X-ray Energy Spectroscopy trace metal concentrations including Pb, Cu and Zn were studied in the common blue mussel, Mytilus edulis. These organisms, sampled at intervals of only 1 km and less for a line transect study of the port of Vancouver, Canada, exhibited dramatic concentration variations. In particular, mussels only 30 m from a point source of lead displayed essentially base-line concentrations, representing a decline of two orders of magnitude. 相似文献