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71.
A. SybousA. El kaaouachi N. Ait Ben AmeurB. Capoen J. HemineR. Abdia A. NarjisH. Sahsah G. Biskupski 《Physica B: Condensed Matter》2011,406(18):3489-3492
We present measurements of the electrical conductivity of barely metallic n-type GaAs that are driven to the metal-insulator transition (MIT) by magnetic field. The experiments were carried out at low temperature in the range (4.2-0.066 K) and in magnetic field up to 4 T. We have determined the magnetic field for which the conductivity changes from the metallic behavior to insulator regime. On the metallic side of the MIT, the electrical conductivity is found to obey σ=σ0+mT1/2 down to 66 mK. Physical explanation to the temperature dependence of the conductivity is given in metallic side of the MIT using a competition between different effects involved in the mechanisms of conduction, like electron-electron interaction effect, Zeeman spin-splitting effect, and weak localization effect. 相似文献
72.
73.
Nouria Chiali-Baba Ahmed Latifa Negadi Ilham Mokbel Ahmed Ait Kaci Jacques Jose 《The Journal of chemical thermodynamics》2012,44(1):116-120
The vapour pressures of (sec-butylamine + water), (cyclohexylamine + water) binary mixtures, and of pure sec-butylamine and cyclohexylamine components were measured by means of two static devices at temperatures between 293 (or 273) K and 363 K. The data were correlated with the Antoine equation. From these data, excess Gibbs functions (GE) were calculated for several constant temperatures and fitted to a fourth-order Redlich–Kister equation using the Barker’s method. The (cyclohexylamine + water) system shows positive azeotropic behaviour for all investigated temperatures. The two binary mixtures exhibit positive deviations in GE for all investigated temperatures over the whole composition range. 相似文献
74.
In this paper we characterize the output feedback stabilization of some coupled systems with and without delay. The proof of the main result uses the method introduced in Haraux (Port. Math., 46:245–258, 1989), which consists of reducing the exponential decay of the closed loop system to an observability inequality of its corresponding conservative adjoint system. 相似文献
75.
Delta doping of diamond constitutes a very promising route to fabricate novel generation of high power and high frequency electronic devices. However, the achievement of abrupt interfaces between highly boron doped and undoped layers requires the shortest residence times of reactive species in the substrate vicinity. We report here on an innovative gas injection system especially designed to reduce this residence time. This technique was applied to fabricate sharp rising and decaying boron interfaces. According to SIMS profiles, the sharpest profiles were obtained on decaying interfaces exhibiting doping gradients close to 1.5 nm per decade over five decades of boron concentrations, namely from 1016 to 1021 atoms/cm3. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
76.
77.
We extend previous results on the preservation of local equilibrium for one-dimensional asymmetric attractive particle systems. The hydrodynamic behavior is studied for general monotone initial profiles. 相似文献
78.
Hossni Ziyat My Youssef Ait Itto Mustapha Ait Ali Abdellah Karim Abdelkhalek Riahi Jean‐Claude Daran 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(2):o90-o93
The two new gem‐dihalogenocyclopropanes (1′S,3R)‐3‐(2′,2′‐dichloro‐1′‐methylcyclopropyl)‐6‐oxoheptanoic acid, C11H16Cl2O3, (2), and (1′S,3R)‐3‐(2′,2′‐dibromo‐1′‐methylcyclopropyl)‐6‐oxoheptanoic acid, C11H16Br2O3, (3), are isostructural. Both present two stereogenic centers at C1′ and C3. The absolute configuration was determined by X‐ray methods. The cyclopropyl rings are unsymmetrical, the shortest bond being distal with respect to the alkyl‐substituted C atom. 相似文献
79.
80.
Mokhtar Benalia Ahmed Yacine Badjah-Hadj-Ahmed Mebrouk Djedid B. Youcef Meklati A. H. Al-Dujaili Fouad Ferkous 《Chromatographia》2007,66(7-8):565-570
The investigation of the analytical properties of two new nematic sulphur-containing liquid crystals 5-(4-methoxyphenyl)-azophenyl)-2-butylthio-1,3,4-oxadiazole
(Phase I) and 5-(4-(propoxyphenyl)-azophenyl)-2-butyl thio-1,3,4-oxadiazole (Phase II) and which comprise units of 1,3,4-oxadiazole
instead of the aromatic cycles, was carried out by gas chromatography using glass capillary columns. For this purpose, many
solutes belonging to various families and having different polarities and volatilities were injected. Comparison of the retention
data of the studied components has shown that Phase II allowed a better separation than the other phase. The two liquid crystalline
materials show a good separation of the studied isomers except for xylene. 相似文献