ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    A neutron diffraction search for non-centrosymmetric thermal oscillations in germanium and silicon (1971)
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 27 (1971), S. 219-222 
    Details
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: A neutron diffraction study was made of the 222 reflection of germanium and silicon between the temperatures of 25 and 500 °C. Care was taken to reduce effects of simultaneous and higher order reflections. Extinction effects were considered, as nearly perfect crystals were employed in the study. Within the sensitivity of the experiment, no 222 neutron intensity was detected. The resulting upper limit placed on β, the cubic atomic potential constant, is roughly one half of a previously suggested value.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0567739471000512
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    A neutron Fourier chopper for single crystal reflectivity measurements: some general design considerations (1971)
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 27 (1971), S. 284-291 
    Details
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Neutron single-crystal analysis of complex protein structures requires the collection of intensity data on a large number of reflections. The use of time-of-flight analysis (in particular Fourier time-of-flight analysis employing phase detection) of diffraction data, offers a significant increase in the efficiency of the use of reactor neutrons. Such a method would facilitate the use of neutron diffraction in protein structure work. In this paper, we investigate the use of the Fourier chopper in single-crystal work. We examine the effect of various system parameters (frequency stability, flight path fluctuations, collimation, sample mosaic spread, inaccuracy in phase detection, and statistical counting errors) and determine general specifications for such an apparatus. None of these specifications appears to be beyond present day technology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0567739471000640
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Neutron Scattering (1972)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Biophysics and Biomolecular Structure 1 (1972), S. 529-552 
    Details
    ISSN: 0084-6589
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.bb.01.060172.002525
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Flux lattice behavior in high-Tc materials studied by neutron depolarization (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 4542-4544 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The depolarization of a neutron beam passing through a sample of the high-Tc superconductor YBa2Cu3O7−δ has been measured as a function of temperature and applied field. The difference in behavior between field-cooled and zero-field-cooled states, the observation of hysteresis correlated with Hc1, and the disappearance of the effect near 55 K (below Tc) suggest an explanation in terms of vortex line lattice formation with possible connection to recently proposed flux line entanglement and melting.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.344862
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Neutron measurements on an epitaxial thin film of YBaCuO : The 5th Joint MMM−Intermag Conference (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 5742-5744 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report evidence for an ordered flux line lattice in a 2-μm epitaxial film of YBaCuO from both neutron depolarization and diffraction measurements. Depolarization occurred when field cooling was done normal to the film plane but not within it; this is consistent with frozen-in vortices. Evidence for ordering of the flux lines comes from intensity maxima observed in difference patterns between field cooled and zero field cooled conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.350146
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Neutron depolarization effects in a high-Tc superconductor (abstract) (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 64 (1988), S. 5815-5815 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Using the polarized beam small-angle neutron scattering spectrometer at the Rhode Island Nuclear Science Center Reactor, we have observed significant depolarization of a neutron beam by passage through polycrystalline high-Tc superconductors, specifically 123 Y-Ba-Cu-O prepared and characterized at the IBM Watson Research Center. We believe that this technique will prove useful in studying aspects of these materials, such as the penetration depth of shielding currents, the presence and structure of trapped flux vortices, and grain size effects on the supercurrent distribution in polycrystalline samples. The two samples showed sharp transitions at 87 and 89 K, and have been studied at temperatures of 77 K; the second sample has also been studied at 4 K. The transition to the superconducting state was monitored by the shift in resonant frequency of a coil surrounding the sample. No measurable depolarization was observed in either sample at 77 K in both the field-cooled and zero-field-cooled states, using applied fields of 0 (nominal), 54, and 1400 Oe. This negative result may be connected with the fact that the material is still in the reversible region as indicated by susceptibility measurements, but it allows an estimate of the upper bound of possible inhomogeneous internal fields, assuming a distance scale for the superconducting regions. For the 10-μm grain size suggested by photomicrographs, this upper bound for the field turns out to be 1.2 kOe, which seems reasonable. At 4 K a significant depolarization was observed when the sample was cooled in low fields and a field of 1400 Oe was subsequently applied. This result suggests that flux lines are penetrating the sample. Further investigations are being carried out to determine the field and temperature dependence of the depolarization, and attempts will be made to model it quantitatively in terms of possible internal field distributions. We are also searching for possible diffraction effects from ordered vortex arrays and plan to extend the measurements to Bi and Tl compositions. These results will be reported in detail elsewhere.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.342215
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Effect of magnetic polydispersion in superparamagnetic colloids on neutron scattering line shapes (1988)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 21 (1988), S. 129-135 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: Neutron scattering profiles from superparamagnetic colloids have been reported by several authors seeking evidence of a difference between a single particle's spatial and magnetic sizes. Calculations are presented which show that the weighting factor present in summing scattering functions over the particle size distribution arising from size-dependent particle magnetization can mask the single-particle transforms sought for. Three experimental precautions are suggested: (1) study only samples of known narrow dispersion (ΔD/D ≤ 30% for magnetite); (2) perform experiments at several values of magnetic field spanning several orders of magnitude; (3) measure both incident and final polarization states of the neutrons. Numerical calculations based on a model allow quantitatively experimentally acceptable limits of sample dispersion to be defined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889887010410
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Effects of Surface Relaxation on Powder Diffraction Patterns of Very Fine Particles (1995)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 28 (1995), S. 274-278 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: Calculations of powder diffraction peaks using a model of tiny (diameter a few nm) spherical crystals log normally distributed in size with and without surface relaxation are presented. The calculated peak shapes are more nearly Gaussian than Cauchy (Lorentzian). Surface relaxation can produce small variations in peak positions, order-dependent peak widths and asymmetric tails. The latter may be quite pronounced in the smaller particles and are qualitatively similar to recent data taken on nanometre-sized crystals. This suggests that comparison of model calculations with X-ray powder data of single peaks or, preferably, entire diffraction patterns (perhaps as part of a Rietveld refinement) may allow probing of surface atom positions in nanometre-sized particles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889894011039
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    The neutron Fourier chopper in protein crystallography (1975)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 8 (1975), S. 20-28 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: It was suggested [Nunes, Nathans & Schoenborn (1971). Acta Cryst. A27, 284–291] that collection of neutron diffraction data from protein crystals could be accelerated greatly by a white-beam Laue technique (to make full use of the reactor spectrum) with Fourier time-of-flight analysis employed to obtain individual reflection intensities. A prototype Fourier chopper has been built. In this paper are described its construction, operation, methods of data analysis, and tests performed with a myoglobin crystal. Although the technique is proved feasible, it is of marginal value when used with a single detector. A spectrometer utilizing an extended detector array is required to realise its full potential.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889875009466
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    The converging-beam small-angle neutron diffractometer: calculated resolution (1978)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 11 (1978), S. 460-464 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: The resolution function of a converging-beam system for use in a small-angle neutron diffractometer is investigated. It is shown that beam convergence in itself has only a small effect on resolution. Also a consideration is the monochromator and the correlation between wavelength and angle which it imposes upon the beam falling on the sample. Only minor modifications of existing monochromator and shield are required to produce a converging beam.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889878013588
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...