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41.
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The energy per particle BA in nuclear matter is calculated up to high baryon density in the whole isospin asymmetry range from symmetric matter to pure neutron matter.The results,obtained in the framework of the Brueckner-Hartree-Fock approximation with two-and three-body forces,confirm the well-known parabolic dependence on the asymmetry parameterβ=(N?Z)/A(β^2 law)that is valid in a wide density range.To investigate the extent to which this behavior can be traced back to the properties of the underlying interaction,aside from the mean field approximation,the spin-isospin decomposition of BA is performed.Theoretical indications suggest that theβ^2 law could be violated at higher densities as a consequence of the three-body forces.This raises the problem that the symmetry energy,calculated according to theβ^2 law as a difference between BA in pure neutron matter and symmetric nuclear matter,cannot be applied to neutron stars.One should return to the proper definition of the nuclear symmetry energy as a response of the nuclear system to small isospin imbalance from the Z=N nuclei and pure neutron matter. 相似文献
43.
Molybdenum single crystals predeformed at low temperature (T1 ≦ 293 K) exhibit during tensile reloading at T2 = 493 K pronounced work softening accompanied by stress serrations and localized slip. It is shown that the initial state for the development of coarse slip bands is the formation of narrow obstacle-free slip channels. The change from the homogeneous dislocation structure to the cell structure proceeds in a heterogeneous and discontinuous manner. 相似文献
44.
The UHV surface preparation of AB materials (crystals and thin films) has been monitored with XPS and AES. Clean and stoichiometric surfaces of AB crystals were prepared by means of low energy ion bombardment and subsequent low temperature annealing. Stoichiometric Cd3As2 and Zn3P2 thin films with very low amounts of C and O were deposited by the evaporation of bulk material in the UHV. The quality of prepared AB crystal and thin film surfaces was sufficient to carry out density of states investigations (UPS, RELS) with success. 相似文献
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A number of recent papers have studied when symmetry causes frameworks on a graph to become infinitesimally flexible, or stressed,
and when it has no impact. A number of other recent papers have studied special classes of frameworks on generically rigid
graphs which are finite mechanisms. Here we introduce a new tool, the orbit matrix, which connects these two areas and provides
a matrix representation for fully symmetric infinitesimal flexes, and fully symmetric stresses of symmetric frameworks. The
orbit matrix is a true analog of the standard rigidity matrix for general frameworks, and its analysis gives important insights
into questions about the flexibility and rigidity of classes of symmetric frameworks, in all dimensions. 相似文献
48.
Sonochemical treatment of natural ground water at different high frequencies: preliminary results 总被引:5,自引:0,他引:5
Naturally occurring ground water polluted by highly volatile chlorinated compounds, with 1,2-dichloroethane as the main contaminant, was sonicated with high frequency ultrasound (361, 620 and 1086 kHz) in order to investigate if results from studies performed with single model compounds in water can be applied to a natural ground water. It was shown that the treated highly volatile halogenated hydrocarbons are almost completely destroyed by ultrasound in natural ground water within 60 min. It also transpired that the naturally occurring inorganic components and gases in the ground water play an important role. 相似文献
49.
G. Schulze und S. Noack 《Fresenius' Journal of Analytical Chemistry》1981,306(2-3):196-200
Zusammenfassung Bei der Bestimmung der effektiven Löslichkeit von Chinoliniummolybdatophosphat in salzsaurer Lösung mit Hilfe von Phosphor-32 wurde untersucht, wie sich die Änderung folgender Arbeitsparameter auswirkt: Spezifische Aktivität der Lösung, Rührgeschwindigkeit, Dosiergeschwindigkeit für das Fällungsmittel, Fällungstemperatur, Art der Trennung von Niederschlag und Lösung, Porenweite der Filter sowie Verluste von Phosphat durch Adsorption an der Oberfläche von Gefäßen und Filtern. Im wesentlichen beeinflussen alle jene Parameter die Löslichkeitswerte stark, die sich auf die Teilchengröße sowohl des Niederschlages als auch der in der Lösung verbleibenden Anteile auswirken. Es wird diskutiert, in welchem Ausmaß das Vorhandensein nicht echt gelöster Teilchen die Löslichkeit ändert.Herrn Prof. Dr. E. Blasius zum 60. Geburtstag gewidmet 相似文献
50.
Dr. Ing. sc. nat H. J. Schulze Prof. Dr. sc. tech. E. Töpfer Ing. G. Gottschalk 《Colloid and polymer science》1979,257(1):98-100
Ohne ZusammenfassungMit 2 Abbildungen 相似文献