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1974 (322)
1Author    K. IlligRequires cookie*
 Title    Lowest Approximation of Relativistic N ucleon-N ucleon Scattering in Functional Quantum Theory  
 Abstract    In s titu t fü r T heoretische P h y sik d e r U n iv e rsitä t T übingen U sing a selfcoupled spinorfield (Ferm icoupling) as a m odel to describe re la tiv istic nucleon-nucleon sc a tte rin g it is show n th a t th e fu n ctio n al S -m a trix co n stru ctio n for re la tiv istic clusters in n o n lin ear spin o rth eo ry proposed by S tu m p f reproduces in low est o rd e r p e rtu rb a tio n th e o ry th e re su lt o b tain e d b y usual q u a n tu m field th eo re tic al m ethods. 
  Reference    (Z. Naturforsch. 29a, 1 [1974]; received 6 October 1973) 
  Published    1974 
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 TEI-XML for    default:Reihe_A/29/ZNA-1974-29a-0001.pdf 
 Identifier    ZNA-1974-29a-0001 
 Volume    29 
2Author    K. SchreckenbachRequires cookie*
 Title    Konversionselektronen von 156Gd nach Neutroneneinfang  
 Abstract    The The conversion electron spectrum of the reaction 155Gd (n, e) 156Gd has been measured up to 8.5 MeV. The results below 4.5 MeV are presented and m ultipolarities are determ ined with these results. E 0 admixtures of the A 1=0 transitions from the 0 + /?-vibrational band to the ground state band were determ ined with 15% accuracy. 156Gd level schemes are discussed and extended by new spin and parity assignments. 
  Reference    (Z. Naturforsch. 29a, 17 [1974]; eingegangen am 1. Oktober 1973) 
  Published    1974 
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 TEI-XML for    default:Reihe_A/29/ZNA-1974-29a-0017.pdf 
 Identifier    ZNA-1974-29a-0017 
 Volume    29 
3Author    E. König, S. KremerRequires cookie*
 Title    Ligand Field-Spin Orbit Energy Levels in the d4 and d6 Electron Configurations of Octahedral and Tetrahedral Symmetry  
 Abstract    The complete ligand field —Coulomb repulsion —spin orbit interaction matrices have been derived for the d4 and d6 electron configurations w ithin octahedral (Oh) and tetrahedral (T j) symmetry. The calculations were perform ed in both the weak-field and strong-field coupling schemes and com­ plete agreem ent of the results was achieved. The energy m atrices are param etrically dependent on ligand field (Dq), Coulomb repulsion (B, C) and spin-orbit interaction (£). Correct energy d ia­ grams are presentend which display the splittings by spin-orbit perturbation as well as the effect of configuration mixing. A pplications to the interpretation of optical spectral data, to the detailed behavior at the crossover of ground terms, and to complete studies in magnetism are pointed out. 
  Reference    (Z. Naturforsch. 29a, 31 [1974]; received August 1 1973) 
  Published    1974 
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 TEI-XML for    default:Reihe_A/29/ZNA-1974-29a-0031.pdf 
 Identifier    ZNA-1974-29a-0031 
 Volume    29 
4Author    W. R. Rutgers, H. De KluiverRequires cookie*
 Title    The Dynam ic Stark-Effect in a Turbulent Hydrogen Plasma  
 Abstract    The profiles of the first three Balm er lines of hydrogen are m easured in a turbulent heating experiment. From the position of Stark satellites the field strength of low frequency oscillations (o) ~ a>pi) is calculated. The energy density in these electrostatic oscillations can amount to \% of the therm al energy. The presence of high frequency oscillations (co ~ ojpe) is concluded from satellites near ± copo from the unperturbed line position. 
  Reference    (Z. Naturforsch. 29a, 42 [1974]; received October 22 1973) 
  Published    1974 
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 TEI-XML for    default:Reihe_A/29/ZNA-1974-29a-0042.pdf 
 Identifier    ZNA-1974-29a-0042 
 Volume    29 
5Author    R. Köhne, A. MeertRequires cookie*
 Title    Induktive Plasmabeschleunigung m it nicht-sinusförmigen stehenden elektromagnetischen Wellen  
 Abstract    Some types of standing r. f. waves are compared and discussed. As a result a new type of a non-sinusoidal standing wave is proposed which leads to an improved inductive acceleration system. Plasm a velocity m easurem ents have been carried out on this system. Numerical calculations are made for the plasm a acceleration process and compared with the experimental values of the velocity. The theory as well as the advantage of the proposed system is verified by the results. 
  Reference    (Z. Naturforsch. 29a, 45 [1974]; eingegangen am 14. Septem ber 1973) 
  Published    1974 
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 TEI-XML for    default:Reihe_A/29/ZNA-1974-29a-0045.pdf 
 Identifier    ZNA-1974-29a-0045 
 Volume    29 
6Author    GeraldW. EnglertRequires cookie*
 Title    Random Walk Theory Applied to Electron Avalanche Formation  
 Abstract    Use of microscopic detail in random walk theory describing the initial formations of a large number of avalanches show that concomitant electron transport coefficients quickly relax to equi­ librium values. This enables the use of random walks having step sizes and probabilities based only on local electric field strengths and densities. A self-consistent avalanche solution which accounts for collective long range Coulomb interactions as well as short range elastic and inelastic collisions between electrons and background atoms is demonstrated for helium. Avalanche growth retardation followed by an abrupt growth augmentation as time proceeds is shown to be associated with the formation of regions of charge density extrema near the avalanche axis and within the axial distance covered by the electron swarm. 
  Reference    (Z. Naturforsch. 29a, 51 [1974]; received 20 August 1973) 
  Published    1974 
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 TEI-XML for    default:Reihe_A/29/ZNA-1974-29a-0051.pdf 
 Identifier    ZNA-1974-29a-0051 
 Volume    29 
7Author    H. P. NeumannRequires cookie*
 Title    The Equation of State for a one-component System  
 Abstract    The Equation of State for a one-component System The cooperative problem for a lattice gas on a plane, square lattice and on a simple cubic lattice is solved by a system of two coupled, transcendental equations, derived by a com bina­ torial method, which describes a homogeneous or periodical particle density on the lattice as a function o f the temperature and the chemical potential of the lattice-gas. For the particle interaction a Hard-Core potential (nearest neighbour exclusion) w ith a soft long-range tail is assumed. The zero-component of the Fourier-transform of this long-range interaction part can be positive or negative. The system of transcendental equations is solved b y a graphic method. As a result, the complete pressure-density state diagram and the pressure-temperature phase diagram can be drawn. The lattice-gas exists in three stable phases: gas, liquid and solid. Three phase changes are possible: condensation, crystallization and sublimation. Critical points of condensation and freezing are examined. The num ber o f possible phases and phase changes at a fixed temperature depends on the geometric structure of the particle interaction. 
  Reference    (Z. Naturforsch. 29a, 65 [1974]; received 5 Oct. 1971 in final form 13 August 1973) 
  Published    1974 
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 TEI-XML for    default:Reihe_A/29/ZNA-1974-29a-0065.pdf 
 Identifier    ZNA-1974-29a-0065 
 Volume    29 
8Author    W. MuschlerRequires cookie*
 Title      
 Abstract    A preceding paper was concerned with the principles of a wave propagation experiment. These appeared suitable for a simultaneous determination of electron concentration Ne and of electron collision frequency v in a magnetoplasma. They considered measurements of the refractive index n and of wave polarization Q, both of which being determined by field strength ratios. In this paper supplementary numerical calculations are carried out using a plasma model that corresponds to con­ ditions observable in the earth's lower day time ionosphere and that is characterized by exclusively positive gradients of Ne . Furthermore, a modification of the original principle is discussed re­ nouncing measurements of n and using only those of Q. Numerical calculations on error propagation demonstrate a significant superiority of the modified version. W KB solutions of coupled wave equa­ tions are used. As the plasma model includes local variations of the plasma parameters, the theory can be applied only to limited height and frequency intervals. These are deduced from the coupling parameter ip. 
  Reference    (Z. Naturforsch. 29a, 75 [1974]; eingegangen am 8. August 1973) 
  Published    1974 
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 TEI-XML for    default:Reihe_A/29/ZNA-1974-29a-0075.pdf 
 Identifier    ZNA-1974-29a-0075 
 Volume    29 
9Author    A. Kawski, J. CzajkoRequires cookie*
 Title    Die Medienabhängigkeit der spektralen Lage der Fluoreszenzbande von Indol und substituierten Indolen  
 Abstract    The To gain information about the nature of the microenvironment of tryptophane residues in pro­ teins, the absorption and fluorescence spectra of such model compounds as indole,-1,2-dimethyl-indole, and 2-phenylindole were examined in n-heptane —n-butanol mixtures at different tempera­ tures (20, 80 and 120 °C). Anomalously large red shifts in the fluorescence bands of these com­ pounds at different n-butanol concentrations in n-heptane indicate that the added n-butanol mole­ cules are concentrated around the solute molecules by electrostatic interactions. The red shift is due to the marked increase in the dipole moment of the excited state and to the number of n-butanol molecules in the solvent shell which can reorient ^themselves during the lifetime of the excited state of the solute molecule. From the spectroscopic data, making use of the "solvent-shift" theory and the statistical model of Mazurenko, the effective dielectric constant of the microenvironment, the average degree of filling up the solvent shell with n-butanol molecules, the average coordination number and the average interaction energy of the solute with the solvent molecules in the ground and excited state, were calculated. 
  Reference    (Z. Naturforsch. 29a, 84 [1974]; eingegangen am 22. September 1973) 
  Published    1974 
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 TEI-XML for    default:Reihe_A/29/ZNA-1974-29a-0084.pdf 
 Identifier    ZNA-1974-29a-0084 
 Volume    29 
10Author    LuisMario Boggia, RobertoRaul Filgueira, OscarManuel Sorarrain, Damiano DamianiRequires cookie*
 Title    Centrifugal Distortion Constants in 1.3 Propiolactone  
 Abstract    The centrifugal distortion constants for 0 — CH2 — C H ,— C = 0 were calculated using Dowling and Watson's formalisms. From the fitting analysis and the deviation of predicted transitions it is concluded that the second formalism must be adopted. For the different parameters we have: A' = 12406.012 ±0.005 M Hz; B' = 5244.456 ± 0.002 M Hz; C = 3869.191 ± 0.002 M Hz; d j = -2.08± 0.05 kHz; d j R = -23.63± 0.95 kHz; d R = -3 3 .4 3 ± 1.69 kHz; d WJ = (0.56± 0.01)X l0 ~ 6; dwK = (5.08 ± 0.22) X 1 0 -6. 
  Reference    (Z. Naturforsch. 29a, 95 [1974]; received August 2 1973) 
  Published    1974 
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 TEI-XML for    default:Reihe_A/29/ZNA-1974-29a-0095.pdf 
 Identifier    ZNA-1974-29a-0095 
 Volume    29 
11Author    A. MüllerRequires cookie*
 Title    Supraleiter mit Schichten der A15-Phasen Nb-Al und Nb-Al-Ge  
 Abstract    Superconductor A conductor has been prepared, consisting of Niobium and an outer layer of the A15-phase Nb-Al and Nb-Al-Ge respectively. The process involves two steps: Coating of Niobium by hot-dipping and subsequent heat treatment. The procedure, the products of reaction and data on the transition temperature Tc and the critical current density Jc of the A15-phase are reported. The maximum values obtained for Tc and / c are 18.5 K (19.3 K) and 5-104A/cm2 (2-104A/cm2) at 5 T and 4.2 K for Nb3Al (Nb3Al, G e). 
  Reference    (Z. Naturforsch. 29a, 99 [1974]; eingegangen am 17. Oktober 1973) 
  Published    1974 
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 TEI-XML for    default:Reihe_A/29/ZNA-1974-29a-0099.pdf 
 Identifier    ZNA-1974-29a-0099 
 Volume    29 
12Author    A. Neckel, P. Rastl, K. Schwarz, Renate Eibler-MechtlerRequires cookie*
 Title    Berechnung der Bandstrukturen nichtstöchiometrischer Vanadiumcarbide V C X  
 Abstract    Herrn Prof. Dr. H. Hartmann aus Anlaß der 60. Wiederkehr seines Geburtstages in Verehrung gewidmet. Band, Structure Calculations on Nonstoichiometric Vanadium Carbides VCx Using the augmented-plane-wave (APW) method the electronic structure of stoichiometric vana­ dium carbide has been computed previously *. Since only nonstoichiometric cubic phases of vana­ dium carbide are stable and all experiments are made with such samples, the energy bands have been determined for some nonstoichiometric VCj; phases {x = 0.87; 0.833; 0.79; 0.75) using the APW virtual crystal (VCA) approximation similar to Schoen's work on TiO 7, 10. Our approach differs from his in two aspects: First, the potential is constructed from the self consistent potential of Ref. 1 instead of using atomic data. Thus, the important self consistent procedure is taken into account at least in an approximated form. Second, a more realistic scheme for occupying the states is suggested. Furthermore, an attempt is made to normalize the wave functions in order to obtain the charge distribution in the crystal. The density of states and the partial densities of states corresponding to the quantum numbers n and I have been computed using an LCAO interpolation scheme. The different VC^ phases show a fairly "rigid band structure" . The Fermi energy and the density of states at the Fermi level increase with decreasing carbon content. The calculated APW-as well as the LCAO-charge distribu­ tion indicate —in accordance with ESCA measurements 32 —that the charge-transfer from vanadium to carbon and the ionicity of VC^ decrease with increasing vacancy concentration. The results of X-ray-emission and heat capacity measurements are discussed in terms of the APW-VCA results. Especially for the X-ray-emission data the agreement between theory and experiment is fair. 
  Reference    (Z. Naturforsch. 29a, 107 [1974]; eingegangen am 24. September 1973) 
  Published    1974 
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 TEI-XML for    default:Reihe_A/29/ZNA-1974-29a-0107.pdf 
 Identifier    ZNA-1974-29a-0107 
 Volume    29 
13Author    R. DreherRequires cookie*
 Title    High Precision Method for Determining Twist Elastic Constants of Nematic Liquid Crystals I. Theory  
 Abstract    In a magnetic field a nematic liquid crystal may sustain a variety of twist modes. Their influence upon light propagating trough the liquid crystal can be used to evaluate the twist elastic constant from simple reflection or transmission measurements. 
  Reference    (Z. Naturforsch. 29a, 125 [1974]; received October 17 1973) 
  Published    1974 
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 TEI-XML for    default:Reihe_A/29/ZNA-1974-29a-0125.pdf 
 Identifier    ZNA-1974-29a-0125 
 Volume    29 
14Author    F. Willig, G. Scherer, W. RothämelRequires cookie*
 Title    Experimental Proof for Electrochemical Non-Equilibrium Saturation Currents in Organic Crystals  
 Abstract    For the same redox ion, diffusion controlled currents have been compared which were obtained at organic crystals and at a gold electrode. These experiments yield quantitative proof for electro­ chemical saturation currents in organic crystals with electrolytic contacts. Essential for this result is a modified voltage step method which enables an application of a high voltage simultaneous with the first contact between the crystal surface and the charge injecting electrolyte. The conditions neces­ sary for the occurrence of a saturation current are discussed which also determine the electrochemical nature of this current corresponding to an ideal non-equilibrium between redox system and organic crystal. 
  Reference    (Z. Naturforsch. 29a, 131 [1974]; received October 17 1973) 
  Published    1974 
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 TEI-XML for    default:Reihe_A/29/ZNA-1974-29a-0131.pdf 
 Identifier    ZNA-1974-29a-0131 
 Volume    29 
15Author    T. S. Rao, S. I. MaliRequires cookie*
 Title      
 Abstract    The kinetics of the reaction between Iäaq and S^O^g has been studied under conditions of production of iodine at a known rate by the persulfate-iodide reaction and its consumption by 5..03 . The effective concentration of iodine during the steady state is measured from its reduction potential at a bright platinum foil electrode. The reaction is of first order with respect to I 3~ and 5..03 individually and hence of over all second order. The specific rate is 1.51 X 1 0 5 M -1 sec-1 and the frequency factor is 1.69X1012 M -1 sec-1 at 25 °C. The energy of activation for the reac­ tion is 9.58 X 1 0 3 cal/mole and the entropy of activation is —2.55 cal/mole deg. 
  Reference    (Z. Naturforsch. 29a, 141 [1974]; received October 26 1973) 
  Published    1974 
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 TEI-XML for    default:Reihe_A/29/ZNA-1974-29a-0141.pdf 
 Identifier    ZNA-1974-29a-0141 
 Volume    29 
16Author    Tetsuhiko Tomiki, Takeo Miyata, Hirokazu TsukamotoRequires cookie*
 Title    The Urbach Rule for the Sodium-and Potassium-Halides  
 Abstract    Phenomenological and physical aspects of the intrinsic tail spectra of the alkalihalides are studied referring to the new results on the intrinsic tail spectra of KBr and K l and to the tempera­ ture dependences of the lowest-energy T -exciton peak of the sodium-and potassium-halides. Sys­ tematically analysing the temperature dependence of the steepness parameter os (T) of the Urbach rule for these halides, it is found that the frequency factor has the value nearly equal to the acoustic phonon energy at X or L of each host lattice and the steepness constant aso becomes larger in passing from fluoride to iodide. This halogen dependence of erso is discussed in terms of the hole band-mass of the /V-level. 
  Reference    (Z. Naturforsch. 29a, 145 [1974]; received January 2 1973) 
  Published    1974 
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 TEI-XML for    default:Reihe_A/29/ZNA-1974-29a-0145.pdf 
 Identifier    ZNA-1974-29a-0145 
 Volume    29 
17Author    P.N T UnwinRequires cookie*
 Title    A New Electron Microscope Imaging Method for Enhancing Detail in Thin Biological Specimens  
 Abstract    An electron microscope imaging method is described which makes use of an electrostatic device, analogous in function to the absorbing phase plate of light microscope, to produce strong con­ trast in biological specimens. This device is situated at the back focal plane of the objective lens in place of a normal objective aperture. The images created provide an especially realistic representa­ tion of the specimen structure and contain information about it that would not necessarily be able to be detected by the conventional bright field method of observation. 
  Reference    (Z. Naturforsch. 29a, 158 [1974]; received 28 March 1973) 
  Published    1974 
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 TEI-XML for    default:Reihe_A/29/ZNA-1974-29a-0158.pdf 
 Identifier    ZNA-1974-29a-0158 
 Volume    29 
18Author    H. Mäder, H. M. Heise, H. DreizlerRequires cookie*
 Title    Microwave Spectrum of Ethyl Cyanide; ^-Structure, Nitrogen Quadrupole Coupling Constants and Rotation-Torsion-Vibration Interaction  
 Abstract    An investigation of the microwave spectra of ethyl cyanide CH 3CH 2CN and the isotopes C H 2D CH 2CN, CH 3CD2CN was carried out. The ground vibrational state of CH 3C H 2CN was re­ examined under high resolution to give three centrifugal distortion constants D j , D j k and D k ■ From the rotational constants of the ground vibrational state of CH 3CH 2CN, CH3CD2CN, CH 2D CH 2CN (symmetric) and CH 2D C H 2CN (asymmetric). C H 3C H 2,3CN and CD3CHDCN a r0-structure is derived. For the isotopes CH 3CD2CN, CH 2D C H 2CN (symmetric) and CH 2DCH2CN (asymmetric) the diagonal elements yaa, ybb and yC c of the quadrupole tensor with respect to the principal axes of inertia were deduced from the hyperfine structure of the rotational lines. The 
  Reference    (Z. Naturforsch. 29a, 164 [1974]; received October 27 1973) 
  Published    1974 
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 TEI-XML for    default:Reihe_A/29/ZNA-1974-29a-0164.pdf 
 Identifier    ZNA-1974-29a-0164 
 Volume    29 
19Author    L. M. Peter, G. VaubelRequires cookie*
 Title      
 Abstract    The precise measurement of the absorption spectra of the spin-forbidden S0 —Tj electronic transitions in aromatic molecular crystals is usually only pos­ sible if some indirect method is used. The mutual annihilation of mobile triplet excitons in such crys­ tals can give rise to delayed fluorescence and the excitation spectrum of this kind of emission can be related to the S0 — Tx absorption spectrum1. In some cases, however, the quantum yield of delayed fluor­ escence may not be sufficiently high to allow mea­ surement of the excitation spectrum. Such a low yield can be due either to a low value of the triplet exciton lifetime (due e.g. to impurity quenching) or to a low value of the quantum yield of fluor­ escence. An alternative method of measuring the S0 — Tx absorption spectrum involves the introduction of a suitable guest material into the crystal and sub­ sequent measurement of the excitation spectrum of the guest phosphorescence 2. The guest is chosen so that it effectively traps triplet excitons i.e. its triplet 
  Reference    (Z. Naturforsch. 29a, 183 [1974]; received 16 November 1973) 
  Published    1974 
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 TEI-XML for    default:Reihe_A/29/ZNA-1974-29a-0183_n.pdf 
 Identifier    ZNA-1974-29a-0183_n 
 Volume    29 
20Author    CharlesA. BarthRequires cookie*
 Title    Photodissociation of Carbon Dioxide in the Mars Upper Atmosphere  
 Abstract    Photodissociation of carbon dioxide produces 0 (*S) atoms and CO (a3Z7) molecules in the Mars upper atmosphere. Calculations of the emission rate of the atomic oxygen 2972 Ä line and the car­ bon monoxide Cameron bands produced by the photodissociation mechanism are factors of 3 and 10, respectively, smaller than the emission rates observed by Mariner ultraviolet spectrometers. Labo­ ratory measurements are needed to understand the discrepancies. 
  Reference    (Z. Naturforsch. 29a, 185 [1974]; received November 26 1973) 
  Published    1974 
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 TEI-XML for    default:Reihe_A/29/ZNA-1974-29a-0185.pdf 
 Identifier    ZNA-1974-29a-0185 
 Volume    29 
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