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  • 1995-1999  (6)
  • 1955-1959  (5)
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Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 4779-4781 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A magnetoresistive random access memory, based on a dynamic random access memory-like floor plan, is demonstrated for an array of magnetic memory cells. Each memory cell consists of a giant magnetoresistive spin-valve structure in series with a GaAs diode. Any single bit in the matrix can be addressed using a coincident current scheme, both for write and read operations. The integration of a series diode in the memory cell yields, for this first demonstrator, read signals of approximately 10 mV. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    facet.materialart.
    Unknown
    London, etc. : Periodicals Archive Online (PAO)
    British journal of psychology. 50 (1959) 333 
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Catalysis letters 32 (1995), S. 319-325 
    ISSN: 1572-879X
    Keywords: Fe-MFI ; ZSM-5 ; C3 alkylation ; cumene ; benzene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Benzene alkylation with isopropanol has been carried out over ZSM-5 and Fe-MFI zeolites. It was observed that Fe-MFI zeolite showed a better selectivity for cumene (isopropylbenzene) andi/(i+n) propylbenzene ratio. This can be attributed to the acidity characteristic of the zeolite. The effects of variation in reaction conditions such as temperature, mole ratio of benzene/isopropanol and WHSV on the activity and selectivity of Fe-MFI are discussed.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 151 (1958), S. 345-350 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The electrical conductivity σ of the specimens is found to obey a relation of the type σ=C exp (−B/k T) over a temperature range 300 to 500° K whereC andB are constants. The experimentally determined values ofB and C are (1)B≈1490 to 2199 (2)C ≈ 0·72 × 10−3 to 4·9 × 10−3 ohms−1 cms−1. The value of the activation energy determined from the values ofB are ≈0·13 to 0·19 e.V. In A.C measurements σ is found to vary with voltage applied across the specimen at a given temperature. The i−V characteristics of metal point semi-conductor contacts are non-linear symmetrical curves and are strongly temperature dependant. The value of the Hall constant (−0·14 cm3/coul) yields carrier concentration as 4·3 × 1019/cm3, and mobility 1·2 cm2 volt−1 second−1. Δϱ/ϱ for the specimen is found to vary asH 2 where ϱ is the resistivity andH the value of magnetic field. The specimens develop a thermo-electric power of magnitude 200 μV/K to 500 μV/K which is fairly constant over the temperature range 300 to 800° K. The sign of the thermo-e.m.f. and of the Hall constant indicate that the specimens are “n” type.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 155 (1959), S. 465-471 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The variation of dielectric constantɛ of pyrolusite (sintered polycrystalline ore of MnO2) with temperature, frequency and voltage has been studied within the frequency range 200 c/s to 10 kc/s. The samples studied show a very high value of dielectric constant ≈ 105. Theɛ-temperature curve indicates thatɛ attains a maximum value at a certain temperature. The temperature at whichɛ attains a maximum value appears to vary from sample to sample. At higher temperatures (i.e. higher than that at whichɛ attains a maximum value),ɛ decreases with temperature asɛ=c/(T−Θ). The dielectric constant is dependent on the frequency; it has a higher value at lower frequencies. The applied voltage across the specimen has a marked influence on the dielectric constant, which increases rapidly with voltage. A capacity with pyrolusite as dielectric shows a hysteresis loop (electrical). The dielectric loss factor tanδ is found to depend on temperature, frequency and voltage. Tanδ attains a maximum value at lower range of frequencies between 300 c/s to 700 c/s, for a given voltage, and temperature. This indicates the existence of dielectric relaxation for these specimens. Tanδ also varies exponentially with temperature. Samples of pyrolusite studied show a piezo electric effect as well. The electromechanical coupling coefficient is found to vary from 2·4×10−5 to 8·8×10−5 e.s.u/ dyne. Slabs cut from the samples of pyrolusite mineral were found to control the frequency of a Hartley oscillatory circuit. The resonant frequency range was found to increase as the thickness of the slab is reduced.
    Type of Medium: Electronic Resource
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  • 6
    facet.materialart.
    Unknown
    Worcester, Mass. : Periodicals Archive Online (PAO)
    Journal of Social Psychology. 47:2 (1958:May) 373 
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  • 7
    ISSN: 1432-1181
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung Es wird eine Differenzenlösung für die Strömung um eine plötzlich in Bewegung gesetzte, unendlich ausgedehnte senkrechte Platte hergeleitet, wobei folgende Annahmen zugrunde liegen: 1. Anwesenheit von anderen Gasen in gewisser Konzentration (CO2, Wasserdampf, etc.) 2. Konstanter Wärmefluß an der Platte Geschwindigkeits- und Temperaturprofile, Widerstandsbeiwerte und Nusselt-Zahlen sind graphisch dargestellt. Die Einflüsse der modifizierten Grashof-ZahlGm, der Eckert-ZahlE und der Schmidt-ZahlSc auf die Strömung werden diskutiert.
    Notes: Abstract A finite-difference solution to the flow past an impulsively started infinite vertical plate is derived by assuming 1) presence of species concentration like water vapour, CO2 etc. and 2) constant heat flux at the plate. The velocity and the temperature profiles, the skin-friction and the rate of heat transfer are shown graphically. The effects of the modified Grashof number,Gm, the Eckert numberE, the Schmidt numberSc on the flow of air are discussed.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-1181
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung Es wird eine Differenzenlösung für die Strömung um eine plötzlich in Bewegung gesetzte, unendlich ausgedehnte senkrechte Platte hergeleitet, wobei folgende Annahmen zugrunde liegen: 1.*Anwesenheit von anderen Gasen in gewisser Konzentration (CO2, Wasserdampf, etc.) 2.*Konstanter Wärmefluß an der Platte Geschwindigkeits- und Temperaturprofile, Widerstandsbeiwerte und Nusselt-Zahlen sind graphisch dargestellt. Die Einflüsse der modifizierten Grashof-Zahl Gm, der Eckert-Zahl E und der Schmidt-Zahl Sc auf die Strömung werden diskutiert.
    Notes: Abstract A finite-difference solution to the flow past an impulsively started infinite vertical plate is derived by assuming 1) presence of species concentration like water vapour, CO2 etc. and 2) constant heat flux at the plate. The velocity and the temperature profiles, the skin-friction and the rate of heat transfer are shown graphically. The effects of the modified Grashof number, Gm, the Eckert number E, the Schmidt number Sc on the flow of air are discussed.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 147 (1957), S. 271-276 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Then-type diode characteristics of natural galena change over top- type after heat treatment in H2S. These galena surfaces treated with H2S were found to show transistor action and photovoltaic effects also. A study of the cleaved surfaces of such galena crystals after heat treatment in H2S revealed that the spreading resistance Rs increases upto a certain depth, below the outer surface indicating the existence of a high resistivity layer. On removing surface layers by carefully scraping with sand paper (a) the rectifying characteristics improved, and (b) photovoltaic effects could be observed. Under these conditions transistor action with current gain=0.83 and voltage gain of about 4 could be obtained.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 31 (1996), S. 2199-2205 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The effects of sulfate ions on the formation and physico-chemical properties of ferric oxide hydroxides were studied using various techniques. Samples prepared from 0.1 M Fe(NO3)3 solution without sulfate ions contain mixtures of goethite and hematite, whereas basic sulfates of varying composition were formed from solutions containing sulfate: iron (III) ratio greater than and equal to one. Goethite samples of very narrow particle size range, spherical shape, microporous nature, high surface area, high true density and low packing density and surface acidity, which are very necessary for good catalysts and ferrite making, were obtained at low sulfate: iron (III) ratios (0.25∶ 0.5).
    Type of Medium: Electronic Resource
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