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1.
K-J. Lehtinen 《Marine environmental research》1984,12(4):273-283
The harpacticoid copepod, Nitocra spinipes Boeck, was used as an experimental animal in a series of tests where the toxicity of different fractions (solid and soluble) of TiO2 industrial waste water was investigated. The tests were performed in brackish water (7). Water temperature was used as a variable in the fractionation of the waste water. Temperature was found to influence the acute toxicity of the waste water. LC50 values for N. spinipes were 0·087 (± 4°C), 0·105 (+ 7°C)) and 0·12% (+ 21°C) of undiluted waste water. At room temperature the animal's fecundity was affected at two intervals, one in dilutions between 0·0003% and 0·001% and the other between 0·03% and 0·3%. An acute toxicity test with the dried solid metal fraction resuspended into clean brackish water had an acute LC50 value of 7·6% of undiluted waste water. The results show that different fractions of the waste water have different harmful biological effects under different temperature conditions. 相似文献
2.
Petroleum hydrocarbons in the sediments of the Bothnian Bay, Baltic proper, Öresund, Kattegatt and Skagerrak were analysed in a survey of oil pollution along the Swedish coast in 1974 and 1975. Sixty-one of these sediment stations were revisited in 1982 and analysed with the methods used in the first survey. The mean content of petroleum hydrocarbons (paraffin-naphthene fraction) in the sediment surface showed a statistically significant increase from 199 to 252 μg g?1 dry wt. The main increase had taken place in the coastal areas. Within 0–20 km distance of urbanized areas (>20 000 inhabitants) petroleum hydrocarbons had increased from 371 to 447 μg g?1. Sediment levels increased from 76 to 117 μg g?1, 20–50 km from urbanized areas. The increase in these areas was equivalent to 0.119 g m?2 yr?1. 相似文献
3.
The lavas of the Nyiragongo volcano in Eastern Zaire contain partially fused granite xenoliths. The relictic feldspars found in these xenoliths were studied by microprobe analysis and by X-ray diffraction methods. Some xenoliths represent originally two-feldspar granites, in others only alkali feldspars or those of an anorthoclase composition were detected. All feldspars are homogeneous without perthitic textures detectable under the microscope. In thebc-diagram of Stewart and Wright all feldspars plot on the analbite-high sanidine join. These feldspars have been perfectly disordered through heating in the melilite-nephelinite magma of the volcano. 相似文献
4.
Martti Lehtinen 《Contributions to Mineralogy and Petrology》1974,47(3):223-230
Unit-cell parameters, c */b* ratios, Δbc values (Stewart and Ribbe, 1969), Or contents and the positions of two of the characteristic infared absorption bands are presented for 16 K-rich and for 5 Na-rich alkali feldspar samples. A more specific interpretation is given for the characteristic absorption bands. It is shown that the position of one of the infrared absorption bands depends on the degree of Al/Si order whereas the other depends both on the degree of Al/Si order and to a lesser degree on chemical composition. It is recommended that a combination of X-ray and infrared data is useful in studying certain mineralogical and petrogenetic problems associated with the alkali feldspars. 相似文献
5.
Kurt Johansson Rune B. Larsen Markku J. Lehtinen Lars Persson Mika Raeisaenen Stig A. Schack Pedersen Paer Weihed Nils-Gunnar Wik 《《幕》》2008,31(1):133-139
The Nordic countries, including Greenland, have a long tradition in mining. The industrial minerals sector is expanding in most Nordic countries and extensive development has taken place during the last few years. The main commodities mined are carbonate rocks, quartz, feldspar, apatite, olivine and talc.
A number of diferent types of dimension stones are quarried in all countries. Rock aggregates are increasingly important, replacing sand and gravel aggregate as construction materials in some countries due to the need to protect ground water supplies. 相似文献
A number of diferent types of dimension stones are quarried in all countries. Rock aggregates are increasingly important, replacing sand and gravel aggregate as construction materials in some countries due to the need to protect ground water supplies. 相似文献
6.
N. J. Lehtinen S. Pohjolainen K. Huttunen-Heikinmaa R. Vainio E. Valtonen A. E. Hillaris 《Solar physics》2008,247(1):151-169
A high-speed, halo-type coronal mass ejection (CME), associated with a GOES M4.6 soft X-ray flare in NOAA AR 0180 at S12W29
and an EIT wave and dimming, occurred on 9 November 2002. A complex radio event was observed during the same period. It included
narrow-band fluctuations and frequency-drifting features in the metric wavelength range, type III burst groups at metric – hectometric
wavelengths, and an interplanetary type II radio burst, which was visible in the dynamic radio spectrum below 14 MHz. To study
the association of the recorded solar energetic particle (SEP) populations with the propagating CME and flaring, we perform
a multi-wavelength analysis using radio spectral and imaging observations combined with white-light, EUV, hard X-ray, and
magnetogram data. Velocity dispersion analysis of the particle distributions (SOHO and Wind
in situ observations) provides estimates for the release times of electrons and protons. Our analysis indicates that proton acceleration
was delayed compared to the electrons. The dynamics of the interplanetary type II burst identify the burst source as a bow
shock created by the fast CME. The type III burst groups, with start times close to the estimated electron-release times,
trace electron beams travelling along open field lines into the interplanetary space. The type III bursts seem to encounter
a steep density gradient as they overtake the type II shock front, resulting in an abrupt change in the frequency drift rate
of the type III burst emission. Our study presents evidence in support of a scenario in which electrons are accelerated low
in the corona behind the CME shock front, while protons are accelerated later, possibly at the CME bow shock high in the corona. 相似文献
7.
J. Magdalenić B. Vršnak S. Pohjolainen M. Temmer H. Aurass N. J. Lehtinen 《Solar physics》2008,253(1-2):305-317
We present a multiwavelength study of the large-scale coronal disturbances associated with the CME?–?flare event recorded on 24 December 1996. The kinematics of the shock wave signature, the type II radio burst, is analyzed and compared with the flare evolution and the CME kinematics. We employ radio dynamic spectra, position of the Nançay Radioheliograph sources, and LASCO-C1 observations, providing detailed study of this limb event. The obtained velocity of the shock wave is significantly higher than the contemporaneous CME velocity (1000 and 235 km?s?1, respectively). Moreover, since the main acceleration phase of the CME took place 10?–?20 min after the shock wave was launched, we conclude that the shock wave on 24 December 1996 was probably not driven by the CME. However, the shock wave was closely associated with the flare impulsive phase, indicating that it was ignited by the energy release in the flare. 相似文献
8.
Th. G. Sahama Martti Lehtinen Pentti Rehtijärvi 《Contributions to Mineralogy and Petrology》1973,39(2):171-174
Single crystals of boehmite, up to 0.1 mm in size, were found in open cavities inside a corundum crystal from the Ratnapura area gem gravels in Ceylon. The unit cell parameters are (X-ray powder pattern): a
0=3.695 Å b
0=12.212 Å, c
0=2.867 Å. The crystallographic orientation is based on X-ray single-crystal precession photographs. The crystals show the faces (it010), (001), (101), and (221). Systematic extinctions agree with the space group Amam. Optical orientation: a, b, c. Refractive indices are given. The mineral is optically positive with a large optic axial angle. 相似文献
9.
It is pointed out that observations of periodic nightglow structures give excellent information on atmospheric gravity waves in the mesosphere and lower thermosphere. The periods, the horizontal wavelengths and the phase speeds of the waves can be determined from airglow images and, using several cameras, the approximate altitude of the luminous layer can also be determined by triangulation. In this paper the possibility of applying tomographic methods for reconstructing the airglow structures is investigated using numerical simulations. A ground-based chain of cameras is assumed, two-dimensional airglow models in the vertical plane above the chain are constructed, and simulated data are calculated by integrating the models along a great number of rays with different elevation angles for each camera. After addition of random noise, these data are then inverted to obtain reconstructions of the models. A tomographic analysis package originally designed for satellite radiotomography is used in the inversion. The package is based on a formulation of stochastic inversion which allows the input of a priori information to the solver in terms of regularization variances. The reconstruction is carried out in two stages. In the first inversion, constant regularization variances are used within a wide altitude range. The results are used in determining the approximate altitude range of the airglow structures. Then, in the second inversion, constant non-zero regularization variances are used inside this region and zero variances outside it. With this method reliable reconstructions of the models are obtained. The number of cameras as well as their separations are varied in order to find out the limitations of the method. 相似文献
10.
In this paper we summarize the theory behind full-profile analysis of IS measurements and report first practical experiences with the GUISDAP (Grand Unified Incoherent Scatter Design and Analysis Package) system designed to perform full-profile analysis of any IS measurements efficiently. By fitting whole plasma parameter profiles over the ionosphere, instead of point values of the parameters supposed to be approximately constant over small range intervals, full-profile analysis is free of underlying assumptions about the slow variation of the plasma parameters as a function of range. We define full-profile analysis as a mathematical inversion problem formalism and explain how it differs from the traditional gated analysis. Moreover, we study the bias introduced to traditional analysis results using realistic model ionospheres. By applying the full-profile method to data generated from the model ionospheres, we demonstrate that full-profile analysis is free from this kind of bias. Lastly, an example of analysis of real data by full-profile and gated analyses is shown. 相似文献