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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 70 (1999), S. 90-96 
    ISSN: 1090-6487
    Keywords: 73.50.Jt ; 81.05.Ys ; 61.43.Er
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract It is established that the Hall effect in Fe/SiO2 nanocomposite films in the activational tunneling conduction range is anomalous, i.e., the Hall resistivity ρh is proportional to the magnetization and is due to the spin-orbit interaction. The parametric coupling of the Hall and longitudinal (ρxx) resistances ρh ∝ ρ xx m (with temperature as the parameter) is characterized by a much lower value of the exponent m than in a uniform ferromagnetic metal. This circumstance is attributed to the characteristic features of the Hall effect mechanism in the hopping regime — in our case, the interference of the amplitudes of tunneling transitions in a set of three granules.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Physics of the solid state 41 (1999), S. 857-863 
    ISSN: 1063-7834
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have investigated the conductance, magnetoresistance, and Hall effect in granular Fe/SiO2 films with size of the iron grains around 40 Å, whose volume fraction x lies in the range 0.3–0.7. The conduction activation regime has been established for x〈0.6. On the insulator side of the transition we observed a giant negative magnetoresistance, falling off sharply as the metal volume fraction decreases. For x〈0.4 we observed a large positive magnetoresistance of premagnetized samples, showing up in fields; ∼100 Oe and characterized by large response times. The field dependence of the Hall effect in the dielectric samples, as in the metallic samples, correlates with their magnetization. We found that the Hall resistance is proportional to the square root of the longitudinal resistance, which cannot be explained by known models of the anomalous Hall effect.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 71 (2000), S. 469-472 
    ISSN: 1090-6487
    Keywords: 73.50.Jt ; 72.80.Tm.470
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The anomalous Hall effect is studied on Fex(SiO2)1−x nanocomposite films with x〈0.7 in the vicinity of the percolation transition (x c ≈0.6). It is found that, as the transition is approached from the side of metallic conduction, the Hall angle nonmonotonically varies, passing through a minimum. A qualitative model for describing the concentration dependence of the anomalous Hall effect is proposed. The model is based on that of the conductivity of a two-phase system near the percolation threshold [9, 10]. The anomalous Hall effect is governed by two conduction channels: one of them (a conducting network) is formed by large metal clusters that are separated by narrow dielectric interlayers below the percolation threshold, and the other is represented by the dielectric part of the medium containing Fe grains; in this part of the medium, the anomalous Hall effect occurs through the interference of amplitudes from the tunneling junctions in a set of three grains. It is shown that, at x〈x c , the network may give rise to a “shunting” effect, which makes the effective Hall voltage even less than the Hall voltage of the dielectric component.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Neurophysiology 27 (1995), S. 85-89 
    ISSN: 1573-9007
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The patch-clamp technique in a whole-cell configuration was used to study the influence of the external concentration of potassium ions on the characteristics of the voltage-dependent potassium current in the plasma membrane of GH3 cells (a cell line isolated from the rat pituitary body tumor). The [K+] out shift from 5 to 100 mM induced a monotonic increase in potassium current with a constant difference between the testing potential and potassium equilibrium potential. The dependence of an activation time constant, τ n , and a steady-state activation,n∞, of the potassium current on [K+] out is of a distinct non-monotononic character with the extremum at 20 mM. Our experiments and theoretical speculations allow us to suppose that the interaction of potassium ions with slowly relaxing charged channel-forming protein groups induced the observed effects.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Neurophysiology 27 (1995), S. 208-213 
    ISSN: 1573-9007
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Changes in electrophysiological and morphological characteristics of N1E-115 murine neuroblastoma cells induced by their incubation in a medium containing verapamil, a blocker of high-threshold calcium channels, and/or increased concentrations of KCl were investigated. On the 3th day of cultivation with 1.0 µM verapamil, the cells showed morphological differentiation and increased density of low-threshold calcium current. Incubation of cells in a high-potassium solution (25 mM) produced inhibition of morphological differentiation and reduction of the density of this current. Morphological and electrophysiological parameters of cells cultivated in a high-potassium medium with verapamil added were close to those of control cells. Verapamil taken at a lower concentration (0.01 µM) did not affect the characteristics of calcium current and morphological differentiation of the cells. Higher concentrations of verapamil (100 µM) substantially suppressed viability of cells (a decrease in cells' projective area, retraction of cell processes, and sharp reduction of calcium current density were observed). The results are consistent with suppositions about functional significance of intracellular calcium level for cell differentiation.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Neurophysiology 26 (1994), S. 331-333 
    ISSN: 1573-9007
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Effects of different forms of C2-5A (2′,5′ApApA; 2′,5′ApApepoxyA; and 3′,5′ApApA) on high voltage-activated (HVA) calcium currents in GH3 cells were studied using the whole-cell patch-clamp recording technique. Addition of 10 µM 2′,5′ApApA, a “core” (dephosphorylated) oligoadenylate, to the pipette solution induced an increase in HVA calcium current. Ten minutes after the whole-cell configuration was established, the current magnitude was enhanced about twofold compared with that observed at 2 min. High concentration of Mg2+ (5 µM) in the pipette solution blocked this effect. 2′,5′ApA and 3′,5′ApApA oligoadenylates, and products of 2′,5′A hydrolysis, adenosine and AMP, did not change the value of HVA current. A chemically modified analog of 2′,5′ApApA (2′,5′ApApepoxyA) has been the oligoadenylate most stable under phosphodiesterase action. Addition of 2′,5′ApApepoxyA to the pipette solution under the same conditions caused a smaller effect than 2′,5′ApApA did.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Russian chemical bulletin 5 (1956), S. 669-677 
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary 1. A study was made of the kinetic laws of the oxidation of ethane to acetic acid in presence of hydrogen bromide. It was shown that the process of acetic acid formation comes to an end long before the reactants are used up. Such “limit phenomena” are explained on the basis of the existence of an initiating reaction that results in the formation of an intermediate product, the amount of which determines the yield of acetic acid. 2. It was established that, whatever method is adopted for initiating the oxidation process by additions of catalyst (hydrogen bromide), the yield of. acetic acid cannot be raised above 40% on the amount of ethane taken. The generality of the phenomenon was pointed out: it is found in other slow-oxidation reactions. 3. With the aid of a method based on the study of the evolution of heat in the reaction mixture during the reaction it was shown that the mechanism of the reaction includes a sequence of two macroscopic stages displaced from one another in time. The first stage — the initiating reaction — is a homogeneous-heterogeneous process. The second stage — the formation of acetic acid initiated by the decomposition of the intermediate product obtained in the first stage — is a homogeneons process. These results confirm the prevalence of the phenomenon of successive macroscopic stages in oxidation processes initiated by additions of homogeneous catalysts.
    Type of Medium: Electronic Resource
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  • 8
    facet.materialart.
    Unknown
    Oxford University Press
    Publication Date: 2016-01-07
    Description: The PDBFlex database, available freely and with no login requirements at http://pdbflex.org , provides information on flexibility of protein structures as revealed by the analysis of variations between depositions of different structural models of the same protein in the Protein Data Bank (PDB). PDBFlex collects information on all instances of such depositions, identifying them by a 95% sequence identity threshold, performs analysis of their structural differences and clusters them according to their structural similarities for easy analysis. The PDBFlex contains tools and viewers enabling in-depth examination of structural variability including: 2D-scaling visualization of RMSD distances between structures of the same protein, graphs of average local RMSD in the aligned structures of protein chains, graphical presentation of differences in secondary structure and observed structural disorder (unresolved residues), difference distance maps between all sets of coordinates and 3D views of individual structures and simulated transitions between different conformations, the latter displayed using JSMol visualization software.
    Print ISSN: 0305-1048
    Electronic ISSN: 1362-4962
    Topics: Biology
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