ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Digitale Medien

Electron density studies of KCl and LiF by γ-ray diffractometry (1985)

Schmidt, M. C. ; Colella, R. ; Yoder-Short, D. R.

[S.l.] : International Union of Crystallography (IUCr)

Acta crystallographica 41 (1985), S. 171-175

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ISSN: 1600-5724

Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001

Thema: Chemie und Pharmazie , Geologie und Paläontologie , Physik

Notizen: Use of hard electromagnetic radiation (λ = 0.12 Å) in diffraction experiments, in conjunction with thin crystals in transmission geometry (Laue case), minimizes multiple scattering, often referred to as the 'extinction problem'. A large crystal slab, completely intercepting the incident beam, was used in this experiment. Several structure factors have been measured in LiF and KCl, with greater accuracy than ever before, using the γ-ray spectrometer of the University of Missouri at Columbia. In the case of LiF the results indicates some compression of the valence electron densities, similar to what has been found earlier for NaF. In the case of KCl all reflections agree well with the values calculated from free-atom Hartree-Fock wave functions except for the 004 and 006, which are appreciably weaker than corresponding reflections with similar or identical sin θ/λ values. This result indicates asphericity of the valence electron density. The 111 is also much weaker than the calculated value, indicating that the negative ions are slightly compressed and the positive ions slightly expanded with respect to the free-ion charge densities.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1107/S0108767385000344

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2

Digitale Medien

The production of charginos of theSU(N, 1) minimal sugra model ine + e − annihilation andp $$\bar p$$ collider experiments (1987)

König, H. ; Ellwanger, U. ; Schmidt, M. G.

Springer

The European physical journal 36 (1987), S. 715-723

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ISSN: 1434-6052

Quelle: Springer Online Journal Archives 1860-2000

Thema: Physik

Notizen: Abstract We present cross sections for the charged lepton production from the lightest charged superpartner particles predicted by theSU(N, 1) Minimal SUGRA model, either the superpartners of the r.h. charged leptons or the Wino/Higgsino. At least one of these should appear in the decay of theZ, which is produced ine + e −-annihilation-presumably soon at the SLC — or inp $$\bar p$$ collider experiments. A large missing mass and strong deviations from back to back production of lepton pairs (and possibly ae-μ final state) would indicate such charged massive intermediate particles.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01630608

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3

Digitale Medien

The neutralinos of theSU(N,1) minimal supergravity model and standard cosmology (1988)

Klemm, A. O. ; Schmidt, M. G.

Springer

The European physical journal 40 (1988), S. 591-598

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ISSN: 1434-6052

Quelle: Springer Online Journal Archives 1860-2000

Thema: Physik

Notizen: Abstract We discuss the effect of the lightest supersymmetric particle (LSP), a Higgsino, and of the gravitino of theSU(N,1) minimal SUGRA model in the standard big bang theory. The freeze out of the LSP depends on the gravitino mass and on the top mass and leads to restrictive lower bounds for these parameters in the model. The decay of a gravitino with mass in the few TeV range leads to a delay in the cooling of the universe before nucleosynthesis. This constitutes the main bound on the gravitino mass of the model. The results are compared with the more standard “simultaneous decay approximation”.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01560230

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4

Digitale Medien

Evidence of a 50-year increase in tropospheric ozone in Upper Bavaria (1994)

Schmidt, M.

Springer

Annales geophysicae 12 (1994), S. 1197-1206

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ISSN: 0992-7689

Quelle: Springer Online Journal Archives 1860-2000

Thema: Geologie und Paläontologie , Physik

Notizen: Abstract In a series of ozone-sonde soundings at the Hohenpeißenberg observatory, starting in 1967, the most striking features are increases of \sim2.2% per year in all tropospheric heights up to 8 km during the past 24 years. These facts have recently been published and discussed by several authors. In this paper, we present some evidence for the increase of tropospheric ozone concentrations during the past 50 years 1940–1990 in the territory of the northern edge of the Bavarian Alps, including the Hohenpeißenberg data. In December 1940 and August 1942, probably the first exact wet-chemical vertical soundings of ozone up to 9 km height were made by an aircraft in the region mentioned. These results were published in the earlier literature. We have converted the results of the flights on 4 days in December 1940 and on 6 days in August 1942 to modern units and have compared them with the Hohenpeißenberg ozone-sonde data of the December and August months. We also compared the data at the ground with the August results of Paris-Montsouris 1886-1898. Our results show an increase of ozone concentration at all tropospheric heights in Upper Bavaria during the past 50 years, compared with the Montsouris data in August during the past 105 years. In the recently published papers, the increases since 1967 were approximated linearly.Our results, extended to the past, show non-linear trends, with steeper increases since 1975-1979. Possible reasons for these findings are discussed. Quite recently (in case of the December months since 1986/87, the August months since 1990), the ozone mixing ratios at and above Hohenpeißenberg seem to have decreased.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/s00585-994-1197-7

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5

Digitale Medien

Wave-particle dualism and the interpretation of quantum mechanics (1992)

Dewdney, C. ; Horton, G. ; Lam, M. M. ; [weitere]

Springer

Foundations of physics 22 (1992), S. 1217-1265

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ISSN: 1572-9516

Quelle: Springer Online Journal Archives 1860-2000

Thema: Physik

Notizen: Abstract The realist interpretations of quantum theory, proposed by de Broglie and by Bohm, are re-examined and their differences, especially concerning many-particle systems and the relativistic regime, are explored. The impact of the recently proposed experiments of Vigier et al. and of Ghose et al. on the debate about the interpretation of quantum mechanics is discussed. An indication of how de Broglie and Bohm would account for these experimental results is given.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01889712

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6

Digitale Medien

The hydration shell of myoglobin (1992)

Parak, F. ; Hartmann, H. ; Schmidt, M. ; [weitere]

Springer

European biophysics journal 21 (1992), S. 313-320

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ISSN: 1432-1017

Schlagwort(e): Monte Carlo ; Crystal water ; Structure refinement

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie , Physik

Notizen: Abstract The space in the unit cell of a metmyoglobin crystal not occupied by myoglobin atoms was filled with water using Monte Carlo calculations. Independent calculations with different amounts of water have been performed. Structure factors were calculated using the water coordinates thus obtained and the known coordinates of the myoglobin atoms. A comparison with experimental structure factors showed that both the low and the high resolution regime could be well reproduced with 814 Monte Carlo water molecules per unit cell with a B-value of 50 Å2. The Monte Carlo water molecules yield a smaller standard R-value (0.166) than using a homogeneous electron density for the simulation of the crystal water (R = 0.212). A reciprocal space refinement of the water and the protein coordinates has been performed. Monte Carlo calculations can be used to obtain information for crystallographically invisible parts of the unit cell and yield better coordinates for the visible part in the refinement.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00188343

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7

Digitale Medien

Hydrogen bonding in basic copper salts: a spectroscopic study of malachite, Cu2(OH)2CO3, and brochantite, Cu4(OH)6SO4 (1993)

Schmidt, M. ; Lutz, H. D.

Springer

Physics and chemistry of minerals 20 (1993), S. 27-32

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ISSN: 1432-2021

Quelle: Springer Online Journal Archives 1860-2000

Thema: Chemie und Pharmazie , Geologie und Paläontologie , Physik

Notizen: Abstract Infrared and Raman spectra of the basic copper salts malachite, Cu2(OH)2CO3, and brochantite, Cu4(OH)6SO4, as well as of deuterated and 13C substituted samples are presented and discussed in terms of group theory and the hydrogen bonds present. The main results are that (i) the hydrogen donor strengths of the OH− ions are strongly increased due to the very great synergetic effect of the copper ions, (ii) the acceptor strengths of the H-bond acceptor groups (SO4 2-, CO3 2-, and OH− ions) are significantly modified by the linkage and coordination of the acceptor atoms — this complicates true assignment of the OH bands observed to the two and six different OH− ions present in malachite and brochantite, respectively -, and (iii) the Cu — O stretching modes at 430–590 cm−1 and 420–520 cm−1 for malachite and brochantite, respectively, exhibit strong, partially covalent Cu — O bonding.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00202247

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8

Digitale Medien

Dynamics of a subconstituent picture of weak interactions (1985)

Dosch, H. G. ; Kremer, M. ; Schmidt, M. G.

Springer

The European physical journal 26 (1985), S. 569-580

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ISSN: 1434-6052

Quelle: Springer Online Journal Archives 1860-2000

Thema: Physik

Notizen: Abstract We use sum rules in order to discuss the dynamics of the simplest subconstituent model of weak interactions with elementary spin 1/2 fermions and scalar bosons. Vacuum condensates of the scalars play an essential role and lead to features quite different from QCD. With a certain vacuum structure vector dominance of the composite W-mesons is a good approximation, and we also see a clear signal for massless fermions in the two-point function of composite fermions. Thus such a model is in good agreement with standard phenomenology. Composite Higgs particles are also investigated. The effective interaction is evidently of the gauge type.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01551801

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9

Digitale Medien

Instanton induced green functions in the superfield formalism (1986)

Fuchs, J. ; Schmidt, M. G.

Springer

The European physical journal 30 (1986), S. 161-174

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ISSN: 1434-6052

Quelle: Springer Online Journal Archives 1860-2000

Thema: Physik

Notizen: Abstract We discuss in detail the supersymmetric instanton calculus of NSVZ and extend it to chiral matter fields in the, adjoint representation. The constant Green functions induced by the instanton of supersymmetricSU (2) gauge theories are calculated systematically for the cases with and without scalar vev's bigger than the scale of the gauge theory and for nonvanishing small masses of chiral fields. Oneinstanton contributions to the Green functions containing four fields without large vevs would disturb clustering; but they are argued to vanish; two-instanton effects then lead to a pattern which quantitatively agrees with factorization and the anomaly relation.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01560691

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10

Digitale Medien

Loop-corrected string field equations from world-sheet Weyl invariance (1989)

Ellwanger, U. ; Schmidt, M. G.

Springer

The European physical journal 43 (1989), S. 485-496

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ISSN: 1434-6052

Quelle: Springer Online Journal Archives 1860-2000

Thema: Physik

Notizen: Abstract We investigate short distance singularities inside the Polyakov path integral in an arbitrary closed bosonic string background due to vertex operators and small handles or holes. The latter are represented in terms of handle or hole operators, which we construct explicitly. The requirement of global Weyl invariance generates loop-corrected equations of motion for the string modes including tadpole terms and self-energy corrections. The relation to theS-matrix and superstrings are discussed briefly.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01506545

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