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61.
The unsteady magnetohydrodynamic flow of a nanofluid past an oscillatory moving vertical permeable semi-infinite flat plate
with constant heat source in a rotating frame of reference is theoretically investigated. The velocity along the plate (slip
velocity) is assumed to oscillate on time with a constant frequency. The analytical solutions of the boundary layer equations
are assumed of oscillatory type and they are obtained by using the small perturbation approximations. The influence of various
relevant physical characteristics are presented and discussed. 相似文献
62.
Steady free convection boundary layer about a truncated cone embedded in a porous medium saturated with pure or saline water at low temperatures has been studied in this paper. The governing coupled partial differential equations are solved numerically using a very efficient finite-difference method. Several new parameters arise and the results are given for some specific values of these parameters. The obtained results for a Boussinesq fluid are compared with known results from the open literature and it is shown that the agreement between these results is very good. 相似文献
63.
64.
I. Pop T. Petrişor A. Giurgiu A. Néda 《Journal of Physics and Chemistry of Solids》1985,46(9):1077-1081
The present study reports magnetic susceptibility, electrical resistivity and specific heat measurements on α-titanium. The experimental results indicate the existence of an anomaly in the temperature dependence of these parameters. The temperature dependence of the specific heat indicates that the anomaly observed in these parameters is a second order phase transition. The similarity between the temperature dependence of the magnetic susceptibility of α-titanium and of chromium suggests that α-titanium is an itinerant-electron antiferromagnet, such as chromium, with the Néel temperature at 276 ± 4 K. 相似文献
65.
I. Pop D. Dadârlat T. Petrişor A. Giurgiu 《Journal of Physics and Chemistry of Solids》1981,42(10):927-930
Magnetic susceptibility as a function of temperature of binary CrAl alloys containing 0.7,1.07,1.35,1.59, 1.79,1.98, 2.18, 2.84, 3.74 and 4.36 at %A1 is investigated. Aluminium, by alloying, acts on the Néel temperature of pure chromium giving rise to a complicated phase diagram. The bahaviour of the magnetic susceptibility as a function of temperature, in the ordered phase, for the samples containing 1.28, 2.18 and 2.84 at %A1 is found to be temperature independent. In the paramagnetic region, for the samples containing between 1.07 and 2.84 at %A1, it is found a decrease of the magnetic susceptibility as a function of temperature. 相似文献
66.
67.
Summary A Theoretical analysis is carried out to study the boundary-layer flow over a continuously moving surface through an otherwise
quiescent micropolar fluid. The transformed boundary-layer equations are solved numerically for a power-law surface velocity
using the Keller-box method. The effects of the micropolar K and exponent m parameters on the velocity and microrotation field as well as on the skin-friction group are discussed in a detailed manner.
It is shown that there is a near-similarity solution of this problem. The accuracy of the present solution is also discussed.
Accepted for publication 1 April 1996 相似文献
68.
I. Pop 《Annali di Matematica Pura ed Applicata》1971,90(1):87-97
Summary The incompressible boundary layer growth on a body of revolution in spinning motion when the outer flow and the angular velocity
of the body are expressed in powers series of √t is studied.
Series at small time are established for the velocity. A simple application is presented in the case of a sphere and the separation
characteristics are studied.
Entrata in Redazione il 23 novembre 1970. 相似文献
69.
Aluminium oxide gel and aluminium oxide-silica gels of different compositions were prepared and activated at different temperatures. The adsorption of NH3 was studied in a McBain type balance at 20 torr and 5×10–3 torr at 25°. The thermodesorption of NH3 was studied at 5×10–3 torr between 25 and 550° at a constant heating rate of 4°/min. The desorption was followed by recording the thermogravimetric curve and the pressure oscillations in the system (p — T curve). The influence of composition and activation temperature is discussed. Chemisorption of a monomolecular layer is assumed in three main types of pores, together with the formation of a second monomolecular layer held by hydrogen bonds.
Zusammenfassung Aluminiumoxyd und Aluminiumoxyd-Kieselsäure Gele von verschiedener Zusammensetzung wurden erzeugt und bei unterschiedlichen Temperaturen aktiviert. Die Adsorption von NH3 wurde mit Hilfe einer McBain Waage unter 20 und 5 · 10–3 Torr Druck bei 25°, weiterhin die Thermodesorption von NH3 unter 5 · 10–3 Torr Druck zwischen 25 und 550° mit 4°/Min. Aufheizungsgeschwindigkeit untersucht. Die Desorption wurde durch die thermogravimetrische Kurve und durch Registrieren der Druckschwankungen in dem System (p — T Kurve) verfolgt. Man diskutiert den Einfluß von Zusammensetzung und Aktivierungstemperatur. Man nimmt eine Chemisorption einer monomolekularen Schicht in drei Porenhaupttypen gemeinsam mit der Ausbildung einer zweiten durch Wasserstoffbindungen gebundenen monomolekularen Schicht an.
Résumé On a préparé des gels d'oxyde d'aluminium et des gels de silice et d'oxyde d'aluminium de diverses compositions; les préparations ont ensuite été activées à différentes températures. On a étudié l'adsorption de NH3 à l'aide d'une balance de type McBain à 25° sous des pressions de 20 et de 5.103torr ainsi que la désorption thermique sous 5.10–3 torr entre 25 et 550° avec une vitesse de chauffage de 4°/mn. On a suivi la désorption en enregistrant les courbes thermogravimétriques et les oscillations de pression dans le système (courbesp — T). On a discuté l'influence de la composition et de la température d'activation. On suppose une chemisorption d'une couche monomoléculaire dans trois types principaux de pores ainsi que d'une seconde couche monomoléculaire maintenue par ponts d'hydrogène.
- . (NH3) 20 . . 5 · 10–3 . . 25°. 5 · 10–3 . . 25° – 550° 4°/ . (p—T ). . , , .相似文献
70.
The temperature dependence of the electrical resistivity of Ni1?xPtx (x = 1, 2, 3, 4, 5, 8, 10, 15, 20, 25 and 30 at.%) between 77 and 700 K has been investigated. The experimental results are interpreted according to the theoretical model developed by Mott. It is shown that for this system Matthiessen's rule is not obeyed. 相似文献