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  • 1
    Electronic Resource
    Electronic Resource
    Heat capacity of3He/4He mixtures (1988)
    Springer
    Journal of low temperature physics 72 (1988), S. 201-212 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We measured the specific heat capacity of three dilute mixtures (2.6, 1.07, and 0.44%) of3He in4He and of pure4He. The4He contribution to the specific heat of the mixture is subtracted, leaving only the3He part. This is fitted to a theoretical expression over the whole temperature range from 10 to 700 mK. Assuming a dispersion relation of the form ε=ħ2 k 2(1+γk 2)/2m*, the fits yield the value of γ and the effective mass m* of each mixture. The average value of γ is −0.076±0.01 A2 and the effective mass in the limit of zero concentration is (2.23±0.02)m 3. These are compared to values deduced from other measurements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00682096
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  • 2
    Electronic Resource
    Electronic Resource
    Exposure of field workers to organophosphorus insecticides: Cotton (1979)
    Springer
    Archives of environmental contamination and toxicology 8 (1979), S. 433-440 
    Details
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract The red blood cell and plasma cholinesterase (ChE) levels of cotton scouts inspecting foliage for insect infestation and damage were monitored. Group means for ChE activity were significantly depressed at one or more time(s) during four of the eight growing seasons studied. Although no symptoms of organophosphate poisoning were confirmed, several scouts exhibited ChE depressions over 50% of pre-exposure levels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01056349
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  • 3
    Electronic Resource
    Electronic Resource
    Spin-Wave instabilities in3He-4He solutions at high magnetic field (1995)
    Springer
    Journal of low temperature physics 101 (1995), S. 833-838 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract During our recent high field pulsed NMR experiments on a spin-polarized saturated3He-4He solution, we observed a long-lived oscillating signal in addition to the usual spin-echo. The oscillations were excited by the application of a single RF tipping pulse of angle greater than some critical value. They were obseravble only for temperatures below 20mK corresponding to values of the spin-rotation parameter μMo ≥3. The signals were not present during experiments on lower concentration solutions. The frequencies of the oscillations were found to scale as the cosine of the tipping angle. The nature and shape of the oscillations suggest that they may be driven by instabilities through a mechanism proposed by Castaing. These instabilities arise due to a modification of the non-linear term in the Leggett equation by the large magnetization gradients present at the edges of the pulsed region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00753399
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  • 4
    Electronic Resource
    Electronic Resource
    Vibrating Wire Viscometers in High Magnetic Fields (1998)
    Springer
    Journal of low temperature physics 110 (1998), S. 1105-1133 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We report an investigation of the intrinsic properties of vibrating wires made of different materials at low temperatures ≈ 10 mK〈T 〈400 mK) and at high magnetic fieldsB ≤ 11.5 T). The aim of this study was to find a material with sufficiently low intrinsic damping even in the highest fields to allow accurate viscometry in highly diluted spin-polarized 3 He- 4 He solutions. A thorough theoretical treatment of the behaviour of vibrating wires (with a high quality factor) in high magnetic fields is presented. Experimental data obtained for NbTi, Ta, W, Ag, manganin and PtW are analyzed within the framework of this theoretical description. Measurements of the field- and temperature dependence of the shift of the resonance frequency and of the internal friction of the vibrating wires clearly indicate that PtW is the most suitable amongst the materials investigated for vibrating wire viscometry in quantum liquids in high magnetic fields.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022316317073
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  • 5
    Electronic Resource
    Electronic Resource
    Calculations of static properties of spin-polarized3He-4He mixtures (1985)
    Springer
    Journal of low temperature physics 60 (1985), S. 243-264 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The theory of dilute mixtures of3He in4He that have been polarized by a strong magnetic field is developed. The interaction between the quasiparticles is taken to be constant, an approximation valid at low temperatures. The polarization of the mixture depends on the strength of the interaction. The internal energy, the specific heat, the osmotic pressure, and the velocity of second sound are also calculated. The specific heat is relatively insensitive to the interaction, but it does change significantly with magnetic field. The osmotic pressure is more sensitive to the effects of the interaction for some3He concentrations and temperatures. The velocity of second sound behaves qualitatively like the osmotic pressure. The measurement of these quantities as a function of temperature and magnetic field is discussed with a view to obtaining the strength of the interaction between quasiparticles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00681642
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  • 6
    Electronic Resource
    Electronic Resource
    Analysis of spin wave resonances in3He-4He mixtures (1986)
    Springer
    Journal of low temperature physics 63 (1986), S. 331-347 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Spin waves have been reported previously in3He-4He mixtures using cw-NMR. The spin waves form standing waves in the rf coil used to detect the NMR signal. Only one resonance was observed, corresponding to ak vector of 1 mm−1. This is in sharp contrast to similar experiments performed on pure3He, where several resonances were seen. An explanation is given of why this occurs and the resonant mode is identified. Furthermore, it is explained why there is an extra width to the resonance for temperatures below 2 mK. This is caused by radiation damping of the resonant mode. The theory is found to be in excellent agreement with the data. Further experiments are suggested, including details of an improved rf coil design, which should lead to information about the quasiparticle interaction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00683772
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  • 7
    Electronic Resource
    Electronic Resource
    Spin-Wave Modes and Spin Diffusion Anisotropy in a 3He-4He Mixture at High B/T (2000)
    Springer
    Journal of low temperature physics 121 (2000), S. 779-784 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We present nmr measurements in a 6.2% 3 He- 4 He mixture carried out at 11.3 T with temperatures down to 3.5 mK, yielding a very high B/T ratio. We have measured the transverse spin diffusion with the spin-echo technique. We observe a saturation of the spin diffusion coefficient at low temperature corresponding to an anisotropy temperature Ta≃13mK. Using the same setup, we were able to excite Silin spin-wave modes in the experimental cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017525224655
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  • 8
    Electronic Resource
    Electronic Resource
    Spin Diffusion Anisotropy in Liquid 3He (2000)
    Springer
    Journal of low temperature physics 121 (2000), S. 767-772 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We report new experiments on the transverse and longitudinal spin dynamics of liquid 3 He polarized by an 11.3T field. At the lowest temperatures probed, the transverse spin diffusion coefficient saturates with an apparent anisotropy temperature of Ta=12±2 mK. This temperature dependence is in accord with the general idea of spin-diffusion anisotropy but the value of Ta is half that expected from extrapolating earlier experiments at a lower field. Strong magnetostatic effects in the form of long-lived spin modes are also observed for small gradients and small tipping angles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017521123746
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  • 9
    Electronic Resource
    Electronic Resource
    Damping of a Vibrating Wire in Spin Polarized Liquid 3He-4He Mixtures (1998)
    Springer
    Journal of low temperature physics 110 (1998), S. 321-326 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In this paper we report measurements of the damping of a vibrating wire in spin polarized liquid helium mixtures. The dilute helium solutions have been cooled by nuclear demagnetisation in high magnetic fields such that the spin polarization for a 0.04% mixture is as high 75%. A PtW alloy vibrating wire has been used to probe the viscosity of the liquid. The increase in viscosity on changing the magnetic field from 3 tesla to 11.5 tesla is a factor 3.5 at the lowest temperatures. The results are compared to theory allowing for both s-wave and p-wave scattering.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022536800798
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  • 10
    Electronic Resource
    Electronic Resource
    Vibrating superleak transducers in3He-4He mixtures (1988)
    Springer
    Journal of low temperature physics 72 (1988), S. 429-450 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We generate second-sound resonances in a cylindrical cavity in3He-4He mixtures using vibrating Nuclepore filters. The properties of the cavity resonances are well described by the theory proposed by d'Humieres et al. The theory predicts the strength of cavity resonances as well as the phase shift between in- and out-of-phase components of the signal. By fitting these quantities we are able to get information about the compliance of the membrane, the distance of the membrane to the backplate, and the resistance to flow through the membrane. This enables us to predict the reflection coefficient of second-sound waves off the transducer. We also study the effect of a strong magentic field on the resonances.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00682152
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