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991.
Trace pollutants analysis in soil by a time-resolved laser-induced breakdown spectroscopy technique 总被引:5,自引:0,他引:5
A. Ciucci V. Palleschi S. Rastelli R. Barbini F. Colao R. Fantoni A. Palucci S. Ribezzo H. J. L. van der Steen 《Applied physics. B, Lasers and optics》1996,63(2):185-190
The results of a joint experiment of IFAM-Pisa and ENEA-Frascati for the detection of traces of pollutants in soil by a time-resolved laser-induced spectroscopy technique are reported. Using samples of soil with known pollutants' concentration [Geochemical Exploration Reference (GXR) silicate from US Geological Survey], we were able to estimate the sensitivity of this Laser-Induced Breakdown Spectroscopy (LIBS) technique to be of the order of some parts per million for a vast class of metallic pollutants, including extremely dangerous soil pollutants such as copper, lead and chromium.ENEA guest with HC&M fellowship 相似文献
992.
993.
G. A. Stergioudis 《Zeitschrift für Physik B Condensed Matter》1993,93(1):1-4
The tendency of boron-containing, iron-based glasses to show non monotonic changes of Curie Temperature (T
c
) and room temperature saturation magnetization (SM) was examined by magnetic measurements and Mossbauer spectroscopy. Depending on B/Fe ratio theT
c
and SM first increased up to a maximum value and then steadily decreased, probably because of a shortrange ordering, due to the strong chemical interaction between iron and boron atoms, leading iron atoms in vicinity with Fe-atoms rather than another TM-atom. Finally, the phenomenon becomes analogous to the order-disorder phenomenon in crystalline alloys. An observed unusual crystallization behaviour, consisting of heterogeneous nucleation, was also ascribed to this ordering, which leads to the formation of associations, acting as the first nuclei of crystallization. 相似文献
994.
995.
996.
By noting changes in the color of samples in a polarization microscope with varying degree of birefringence, the effect of
a weak static magnetic fields (2 and 4 kOe) on molecules of glassy polymers has been observed. Variations in the nonmonotonicity
of the rate of discontinuous creep at +18° were studied interferometrically. It is shown that the abruptness of the deformation
jumps varies in a magnetic field, where this abruptness is assumed to be due to the existence of strong physical junctions
between the kinetic units of deformation. The reactivity of the polymers to the magnetic field stands in satisfactory correspondence
with their magnetic susceptibilities. Results show that such nonmagnetic materials as glassy polymers can noticeably alter
their deformational properties in response to the action of magnetic fields.
Fiz. Tverd. Tela (St. Petersburg) 39, 1690–1692 (September 1997) 相似文献
997.
G. A. Dvoyan A. G. Gulyan R. M. Martirosyan G. A. Pirumyan A. S. Agadzhanyan 《Radiophysics and Quantum Electronics》1997,40(9):793-797
We describe a new method of constructing a device for simultaneous measurement of the relative amplitude and phase difference
of microwave signals, using complex phase manipulation of input signals. It is shown that systematic errors of measurement
are significantly lower in the proposed amplitude and phase meter. Root-mean-square values are obtained for a system with
nonideal elements. A block diagram of the device is presented and its principal characteristics are described.
Institute of Radiophysics and Electronics, Armenian Academy of Sciences, Erevan. Translated from Izvestiya Vysshikh Uchebnykh
Zavedenii, Radiofizika, Vol. 40, No. 9, pp. 1182–1188, September, 1997. 相似文献
998.
L. A. Kurdanchenko B. V. Petrenko I. Ya. Subbotin 《Ukrainian Mathematical Journal》1997,49(11):1742-1746
We prove that, in an Artinian module, the upper FC-hypercenter over an infinite FC-hypercentral locally solvable group has a direct complement. Thus, we obtain a generalization of one of Zaitsev’s theorems and one of Duan’s theorems. 相似文献
999.
1000.
It was shown by G. A. Jones and the first author in [8] that underlying any map on a compact orientable surface S there is a natural complex structure making S into a Riemann surface. In this paper we consider regular maps and enquire about the Weierstrass points on the underlying Riemann surface. We are particularly interested to know when these are geometric, i.e. whether they lie at vertices, face-centres or edge-centres of the map. 相似文献