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11.
Georg von Georgievics 《Monatshefte für Chemie / Chemical Monthly》1885,6(1):754-759
Ohne ZusammenfassungDiese Untersuchung ist vor mehr als Jahresfrist infolge Eintrittes in die chemische Praxis abgebrochen worden. Äussere Verhältnisse machen die Vollendung der begonnenen Versuche auch weiterhin unmöglich und sehe ich mich desshalb veranlasst, meine Beobachtungen zu veröffentlichen. 相似文献
12.
W. von Oertzen 《Acta Physica Hungarica A》2003,18(2-4):157-170
Nuclear clustering in N = Z nuclei has been studied for many decades. Of particular relevance are states close to the decay thresholds, as described by the Ikeda diagram. Recent interest has focused on loosely bound systems as observed with exotic nuclei. Extreme deformations are simultaneously observed. In the deformed shell model these are referred to as super- and hyper-deformation. Another feature related to clustering is the development of octupole deformations. A possible approach to describe these states is to use explicitly molecular concepts, with neutrons in covalent binding orbits. Examples for molecular structure in beryllium isotopes and in other neutron-rich light nuclei (carbon and neon) are now well established. The predicted chain states in the carbon isotopes are the first example of structures with an axis ratio of 3:1. A threshold diagram for molecular configurations in nuclei with clusters and covalent neutrons can be established. 相似文献
13.
Kerstin Paech Adrian Dumitru Jürgen Schaffner-Bielich Stefan Schramm Horst Stöcker Gebhard Zeeb Detlef Zschiesche 《Acta Physica Hungarica A》2004,21(2-4):151-156
The measured particle ratios in central heavy-ion collisions are investigated within a chemical and thermal equilibrium chiral SU(3) σ?ω approach. Contrary to the commonly adopted non-interacting gas calculations, the chiral SU(3) model predicts modified effective hadron masses and effective chemical potentials in the medium and a transition to a chirally restored phase at high temperatures or chemical potentials. the influence of three different types of phase transitions is investigated. We show that the deduced freeze-out values considerably depend on the underlying model while the quality of the fit is approximately the same. 相似文献
14.
The association of complex formation with static quenching in CT systems was investigated. Evaluation of the data made evident
that the inner filter effect must be allowed for. Time-resolved and temperature-dependent stationary measurements of fluorescence
led to the separation of dynamic and static quenching components. The static quenching constant is discussed with respect
to the equilibrium constant of complex formation determined by absorption spectroscopy. 相似文献
15.
16.
W. von der Linden 《Applied Physics A: Materials Science & Processing》1995,60(2):155-165
The reconstruction of physical quantities from (computer-) experimental data is very often hampered by the presence of noise, insufficient information and above all by the ill-posed nature of the underlying inversion problem. It will be demonstrated that the maximum entropy concepts is particularly suited for this type of data-analysis problems. It is based on Bayesian statistics and provides a consistent probabilistic theory to obtain unbiased results, independent of any model assumptions. This is particularly desirable if there is no additional information to justify these hypotheses. If, on the other hand, additional prior knowledge is available, it can be effectively incorporated into the computation, leading to more stringent confidence intervals. 相似文献
17.
Horst Szambien 《Results in Mathematics》1992,22(1-2):619-621
18.
E. Chikoidze Y. Dumont H.J. von Bardeleben J. Gleize F. Jomard E. Rzepka G. Berrerar D. Ferrand O. Gorochov 《Applied Physics A: Materials Science & Processing》2007,88(1):167-171
ZnO:Mn thin films are grown by the metal organic chemical vapor deposition technique. Mn (x) varies in the 0<x<0.44 range.
Vegard’s law has been verified for the lattice parameters. Electron paramagnetic resonance (EPR) measurements prove the substitutional
incorporation of Mn2+ on zinc sites. The behavior of the EPR line width regarding temperature is discussed. All ZnO:Mn layers show antiferromagnetic
interaction and a J1/kB=-15 K effective exchange constant. The optical band gap of ZnO:Mn increases with the manganese concentration. Raman spectroscopy
reveals a Mn-related scattering band.
PACS 71.55.Gs; 75.50.Pp; 61.10.Nz; 76.30.Fc; 75.30.Et; 78.40.-q 相似文献
19.
T. Hansel J. Müller C. Falldorf C. von Kopylow W. Jüptner R. Grunwald G. Steinmeyer U. Griebner 《Applied physics. B, Lasers and optics》2007,89(4):513-516
Digital holographic shape measurements using femtosecond laser pulses are reported. For contouring of very fast moving objects,
the simultaneous generation of at least two spectrally separated ultrashort pulses is required. To deliver this particular
spectral signature at high pulse energies, a chirped-pulse Ti:sapphire laser amplifier was modified to emit two spectrally
separated pulses with energies above 1 μJ each. The wavelength separation of these pulses was adjustable within the 50 nm
gain bandwidth, cutting out two distinct wavelength peaks by a variable double-slit assembly in a prism sequence. A Michelson-type
interferometer was employed to perform the two-wavelength contouring. The phases of the holograms and the phase differences
are calculated numerically, which allow us to deduce the contour lines of the topology of the object. The suitability of the
light source for digital holography is demonstrated with contouring of stationary objects and the potential for high-speed
applications is indicated.
PACS 42.40.-i; 42.60.By 相似文献
20.
von Eynatten G. Ritter T. Bömmel H. E. Dransfeld K. 《Zeitschrift für Physik B Condensed Matter》1987,65(3):341-345
A new model is presented which explains well the dramatic decrease of the Mössbauer line intensities with raising temperatures for freely dispersed iron microscrystals. In contrast to other theories which consider mainly vibration to be responsible we discuss here the decrease in terms of large amplitude diffusive rotational or translational jumps of the particles. Such diffusive jumps lead — in agreement with the observation — to a strong reduction of the Mössbauer-intensity without broadening the line width in a noticeable way. The typical potential well for a diffusing particle in an equilibrium position is derived quantitatively to be 13 meV. The model might be important also for a new understanding of the dynamics of catalytic clusters either in contact with each other or with larger solid surfaces.Part of this work was supported by the DFG Sonderforschungsbereich 306, Konstanz 相似文献