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1978[X]
41Author    Binh Dinh-Ngoc, Wolfram SchnabelRequires cookie*
 Title    Primary Reactions during the Free Anionic Polymerization of ß Nitrostyrene  
 Abstract    /J-Nitrostyrene (/5NS) was irradiated at r. t. in solutions of hexamethylphosph. triamide (HMPT) with 50 ns pulses of 15 MeV electrons. It was found that /3NS reacts with solvated electrons almost encounter controlled (&(e^,iv + /?NS) = (9 3) • 10 9 1/mol s) forming the radical anion • /JNS -. The optical absorption spectrum of the latter was recorded in dilute solutions ([/SNS] < 5 X 10 -3 mol/1). At higher /SNS concentrations the formation of an additional optical absorp-tion after the pulse in the wavelength range between 460 nm and 570 nm was detected, which is attributed to the reaction of /?NS with -/SNS -yielding the dimeric radical anion (-/SNS-/SNS -). The rate constant for this process is 4 X 10 7 1/mol s. At low /?NS concentrations (< 5 X 10~ 3 mol/1) the transient spectrum decayed by a second order process (k2 — (2.2 ± 0.5) • 10 9 1/mol s). This process is correlated to the neutralization of radical anions by cations formed initially. At [/SNS] > 5 X 10~ 3 mol/1 only the band at 630 nm decays according to second order kinetics. This band is correlated to the part of the anions with the highest electron density, the nitro groups. At wavelengths below 570 nm the absorptions of various species overlap. These species decay by different rate laws. 
  Reference    Z. Naturforsch. 33a, 253—256 (1978); received January 17 1978 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0253.pdf 
 Identifier    ZNA-1978-33a-0253 
 Volume    33 
42Author    H. TassoRequires cookie*
 Title    Energy Principle for Dissipative Two-fluid Plasmas  
 Abstract    An energy principle for the dissipative two-fluid theory in Lagrangian form is given. It rep-resents a necessary and sufficient condition for stability allowing the use of test functions. It is exact for two-dimensional disturbances but is still correct in terms of perturbation theory for long wavelengths along the magnetic field. This may well find application in tokamak plasmas. A discussion of the general case and its relation to the stability of flows in hydrodynamics is given. This energy principle may be applied for estimating the magnitude of residual tearing modes in tokamaks. 
  Reference    Z. Naturforsch. 33a, 257 (1978); received January 17 1978 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0257.pdf 
 Identifier    ZNA-1978-33a-0257 
 Volume    33 
43Author    A. Shivarova, I. ZhelyazkovRequires cookie*
 Title    High-frequency Surface Waves in a Current Carrying Hot Plasma Column  
 Abstract    The propagation of high-frequency axially-symmetric surface waves along a current-carrying hot plasma column in a glass tube is investigated by means of a kinetic plasma model. The wave spectrum and the wave damping rate are obtained. Our results agree with the experimental data for surface wave propagation in a gas-discharge plasma at low pressures. It is found that the wave damping is mainly due to the Landau mechanism. 
  Reference    Z. Naturforsch. 33a, 261—268 (1978); received December 9 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0261.pdf 
 Identifier    ZNA-1978-33a-0261 
 Volume    33 
44Author    A. Ichimiya, G. Lehmpfuhl, W. -BerlinRequires cookie*
 Title    Axial Channeling in Electron Diffraction  
 Abstract    Kossei patterns from Silicon and Niobium were obtained with a convergent electron beam. An intensity maximum in the direction of the zone axes [001] and [111] of Nb was interpreted as axial channeling. The intensity distribution in Kossel patterns was calculated by means of the Bloch wave picture of the dynamical theory of electron diffraction. Particularly zone axis patterns were calculated for different substance-energy combinations and they were compared with experi-mental observations. The intensity distribution in the calculated Kossel patterns was very sensitive to the model of absorption and it was found that a treatment of the absorption close to the model of Humphreys and Hirsch [Phil. Mag. 18, 115 (1968)] gave the best agreement with the experi-mental observations. Furthermore it is shown which Bloch waves are important for the intensity distribution in the Kossel patterns, how they are absorbed and how they change with energy. 
  Reference    Z. Naturforsch. 33a, 269—281 (1978); received January 27 1978 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0269.pdf 
 Identifier    ZNA-1978-33a-0269 
 Volume    33 
45Author    H. Melle, E. MenzelRequires cookie*
 Title    Superstructures on Spherical Gold Crystals  
 Abstract    Spherically shaped crystals of gold were grown by solidification of a drop of melt in UHV. Their surfaces were investigated in situ by RHEED. The superstructures (001) (5x20) and (110) (1 X 2) were observed again. Further superstructures were found: on (001) vicinal planes, (227) (1 X 1), (111) (23 X 1) and (551)c(l X 1). Several of the new structures are related to struc-tures already known. 
  Reference    Z. Naturforsch. 33a, 282—289 (1978); received December 27 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0282.pdf 
 Identifier    ZNA-1978-33a-0282 
 Volume    33 
46Author    Dipak Chakraborty, Gerhard LehmannRequires cookie*
 Title    On the Fine Structure in the Infrared Spectra of Clear Natural Quartz, Amethyst, Citrine and Synthetic Quartz Crystals in the 3400 cm" 1 Region  
 Abstract    The fractional intensities of different infrared vibration bands due to hydrogen impurities have been studied in clear natural quartz, amethyst, citrine and synthetic quartz. Integral absorptions of the different bands were found to increase linearly with total hydrogen concentration. The differences in intensity ratios for some prominent bands are distinctive for the type of quartz in some cases. The ratios of isotropic to anisotropic absorption from hydrogen impurities were found to increase with total hydrogen concentration. 
  Reference    Z. Naturforsch. 33a, 290—293 (1978); received January 19 1978 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0290.pdf 
 Identifier    ZNA-1978-33a-0290 
 Volume    33 
47Author    Fr KaiserRequires cookie*
 Title    Coherent Oscillations in Biological Systems I Bifurcation Phenomena and Phase Transitions in an Enzyme-Substrate Reaction with Ferroelectric Behaviour  
 Abstract    The concept of long range coherence in biological systems of Fröhlich and its physical basis as well as his general theoretical considerations leading to the brain wave model are reviewed. The importance of these ideas is stressed both, as a possible explanation of the increasing experi-mental results and as a starting point to allow a theoretical description of biological events. The brain wave model is studied in detail. All possible bifurcations and the stability of the steady states is considered. The existence, stability and direction of bifurcation of a stable limit cycle is proven. The system may exhibit different types of phase transitions when it is externally disturbed. Phase plane diagrams, arguments of catastrophe theory and approximations to the model equations give a qualitative description of the system's time behaviour. Correspondence between this limit cycle model and nerve impulse generating models is established. 
  Reference    Z. Naturforsch. 33a, 294—304 (1978); received October 4 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0294.pdf 
 Identifier    ZNA-1978-33a-0294 
 Volume    33 
48Author    W. HelfrichRequires cookie*
 Title    Steric Interaction of Fluid Membranes in Multilayer Systems  
 Abstract    The out-of-plane fluctuations of fluid membranes are sterically hindered in multilayer systems. The repulsive interaction associated with the steric or excluded-volume effect is studied theoreti-cally by two methods. The interaction energy per unit area of membrane is derived as a function of temperature, membrane curvature elasticity and mean membrane spacing; it is inversely proportional to the square of the latter. Steric repulsion is estimated for lecithin bilayers in water. There and in other cases, it may compete with van der Waals attraction. 
  Reference    Z. Naturforsch. 33a, 305—315 (1978); received September 30 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0305.pdf 
 Identifier    ZNA-1978-33a-0305 
 Volume    33 
49Author    ThH. De Keijser, E. J. MittemeijerRequires cookie*
 Title    Analysis of X-ray Diffraction Line Broadening using a Non-ideal Standard Specimen  
 Abstract    In practice a standard specimen used for the elimination of instrumental broadening, by de-convolution, is never ideal. The instrumental line profile always contains some additional broaden-ing due to finite particle size and distortion present in the standard specimen. Further it is some-times unavoidable to use a standard specimen of a material different from the material to be analyzed, leading to reflections at incorrect sin 0-values (different spectral broadening). Firstly the effect of these deficiencies on the Fourier coefficients of the pure line profile is analyzed. Secondly the consequences for size-strain analysis are considered. A correction [Eq. (3.4) ] for the difference in spectral broadening between the exact and the approximate instrumental line profile is given. To avoid serious errors, this correction should be performed before particle size and strain are determined according to the so-called Warren-Averbach analysis. Accurate relative determinations of size and strain are possible even in the case that the line profile under investigation and the line profile of the reference specimen are at different sin 0-values. It is suggested that standard specimens which cause noticeable structural broadening can be used profitably. 
  Reference    Z. Naturforsch. 33a, 316—320 (1978); received December 18 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0316.pdf 
 Identifier    ZNA-1978-33a-0316 
 Volume    33 
50Author    P.A F Büger, J. H. Blum, SchillingRequires cookie*
 Title    The Stewart-Thompson Theory applied to the Glow Discharge  
 Abstract    The surface topography developed on copper-based and ferrous alloys after being sputtered in a glow discharge lamp and in an ion microprobe was studied by means of a scanning electron microscope and an ion microprobe mass analyser. The observed surface topography, though obtained under completely different conditions, was found to be similar to that predicted by the theory of Stewart and Thompson. 
  Reference    Z. Naturforsch. 33a, 321—326 (1978); received September 16 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0321.pdf 
 Identifier    ZNA-1978-33a-0321 
 Volume    33 
51Author    J. BletryRequires cookie*
 Title    Geometrical Models for Liquid Metals and Alloys  
 Abstract    The structure of monoatomic liquids in the static approximation is described by a soft sphere model and the corresponding equation of state is derived. This geometrical model is then ex-tended to binary liquid or amorphous substitution alloys where both components have the same size. The structure of these alloys is shown to be determined by the first neighbour order parameter which is positive, negative or zero for segregated, ordered or disordered alloys respec-tively. The variations of the partial structure factors with concentration are presented for these three cases. Size effects are then studied by varying the ratio of atomic diameters. Many experi-mental results are shown to fit this simple framework. 
  Reference    Z. Naturforsch. 33a, 327—343 (1978); received November 15 1977* 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0327.pdf 
 Identifier    ZNA-1978-33a-0327 
 Volume    33 
52Author    H. H. Afify, F. M. Abdel-Kerim, H. F. Aly, A. A. ShabakaRequires cookie*
 Title    The Electrical Conductance of Some Alkali-and Divalent Transition Metal TCNQ Salts  
 Abstract    The electrical resistivity of the tetracyanoquinodimethane salts of ten alkali and transition metal cations has been investigated at temperatures from 300 to 470 K. The measurements indicate a phase transition, the activation energy of conductance being smaller in the high temperature region. The nature of this phase transition is discussed. 
  Reference    Z. Naturforsch. 33a, 344—346 (1978); received September 9 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0344.pdf 
 Identifier    ZNA-1978-33a-0344 
 Volume    33 
53Author    G. Brunner, P. MorgensternRequires cookie*
 Title    Zur Eignung von Edelgas-bzw. Edelgas-Stickstoff-Gemischen als Detektionsgase in Proportional-Szintillations-Detektoren Suitability of Noble Gases and their Mixtures, Partly with Nitrogen, as Detection Gases in Propor- tional Scintillation Counters  
 Abstract    Ar, Ar/N2, Ar/Xe, Kr and Kr/Xe were tested in a spherical gas scintillation counter. The examinations led to the conclusion that only the four lowest lying states 3 P2, 3 Pi, 3 Po, x Pi of the noble gas atoms in the luminescence process are involved. From a practical point of view, the best energy resolution could be reached by Xe. We got a full width at half maximum of 83 eV for boron X-rays (183 eV). 
  Reference    Z. Naturforsch. 33a, 347—352 (1978); eingegangen am 11. Januar 1978 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0347.pdf 
 Identifier    ZNA-1978-33a-0347 
 Volume    33 
54Author    R. Kretner, G. DickelRequires cookie*
 Title    Quantitative Isotopenanreicherung im Thermodiffusionstrennrohr  
 Abstract    In applying the theory of the thermal diffusion separation column with containers at both ends to quantitative isotope enrichment, the volume of the column has not yet been exactly accounted for. A formula is derived which describes the effective volume as a function of the characteristic values of the enrichment apparatus. An iteration method for calculation of the effective volume is presented. The theoretical values are compared with experimental results in the case of time dependent enrichment of two isotopes (13 CH4, 14 CH4) and three different ways of enrichment. Agreement within the experimental limits of error of ± 6% was found. 
  Reference    Z. Naturforsch. 33a, 353 (1978); eingegangen am 22. Dezember 1977 Quantitative Isotope Enrichment in Thermal Diffusion Separation Column 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0353.pdf 
 Identifier    ZNA-1978-33a-0353 
 Volume    33 
55Author    H. P. Waschi, H. Stoll, H. PreußRequires cookie*
 Title    Ab-initio and PCILO Calculations of Diamond Clusters and the Corresponding Saturated Hydrocarbons  
 Abstract    Closed-shell diamond clusters and saturated hydrocarbons are investigated with PCILO and ab-initio Hartree-Fock using very small basis sets. The ab-initio distances for the C—C bonds differ by 5% or less, the PCILO distances by 2 to 2.5% from experimental data. The dependence of bond lengths and force constants on the cluster construction is studied. For selected molecules the effect of intermolecular rotations on the total energy is considered. 
  Reference    Z. Naturforsch. 33a, 358—365 (1978); received December 30 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0358.pdf 
 Identifier    ZNA-1978-33a-0358 
 Volume    33 
56Author    CarlosC. Nascimento, Pe, Brasil, IraMark BrinnRequires cookie*
 Title    Relative Stabilities of Dihaloethylenes and Dihaloethanes. A Theoretical Study [1]  
 Abstract    CNDO/2-type calculations have been carried out on 1,1-dihaloethylenes, 1,2-dihaloethylenes and 1,2-dihaloethanes treating all four halogens. The energy was minimized with respect to the coordinates by use of the FORCE method. The results are consistent with experimental isomer and conformer stabilities and it is shown, by means of a cis-trans correlation diagram and cal-culated intramolecular atomic interaction energies, that previous explanations of the apparent halogen-halogen attraction are inconsistent with our results. 
  Reference    Z. Naturforsch. 33a, 366—372 (1978); received December 7 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0366.pdf 
 Identifier    ZNA-1978-33a-0366 
 Volume    33 
57Author    H. Sterk, J. KalcherRequires cookie*
 Title    Einflüsse para-und diamagnetischer Substanzen auf 4 H T1-Relaxationszeiten von Alkoholen Influences of Para-and Diamagnetic Substances on the i H T Relaxation-time of Alcohols  
 Abstract    The homologous series of Alcohols from Butanol to Tetradecanol was investigated with para-and diamagnetic shift-reagents with regard to their influences on the X H relaxation-times. For the protons of the OH-, the CH2 —0-, and the (CH2) ^-groups, with increasing distance from the shift-molecule, a decreasing influence on the Tj-relaxation times could be verified. The Methylgroups of the long-chained Alcohols show an inverse tendency which can be explained by paramagnetic and Dipole-Dipole-Interactions with neighbour-complexes. The purely paramagnetic influence on the 7\-relaxation times of the different protons may be obtained by subtracting the diamagnetic influence from the total. 
  Reference    Z. Naturforsch. 33a, 373—376 (1978); eingegangen am 24. Januar 1978 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0373.pdf 
 Identifier    ZNA-1978-33a-0373 
 Volume    33 
58Author    E. Koglin, H. J. SchenkRequires cookie*
 Title    Phosphorescence of Manganese(II) in Single Crystals of [Mn(C0(NH2)2)6](C104)2  
 Abstract    The 4 Tig(t2K eg) —v 6 Aig(t!g eg) phosphorescence spec-trum of manganese (II) in single crystals of [Mn(CO(NH2)2)6] (CIO,), has been recorded in the temperature range of 4.2 to 298 K. With decreasing temperature the emission maximum is shifted from 17138 cm" 1 (298 K) to 16 809 cm" 1 (4.2 K). This red shift points to a linear thermal expansion coefficient of a = 24 • 10 -6 K _1 . Crystal field parameters of Dq = 748 cm -1 and ß = 827cm _1 have been calculated from the room temperature absorption and excitation spec-tra. 
  Reference    Z. Naturforsch. 33a, 377—379 (1978); received January 27 1978 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0377_n.pdf 
 Identifier    ZNA-1978-33a-0377_n 
 Volume    33 
59Author    Veit Eck, Günther Lauer, Armin Schweig, Walter Thiel, Hans VermeerRequires cookie*
 Title    Erzeugung und Untersuchung des Cyclo- pentadienons mit der Methode der temperatur- abhängigen Photoelektronenspektroskopie  
 Abstract    Using our VTPES technique cyclopentadienone is gener-ated in the gas phase at 500 —600 °C from the three dif-ferent precursors cyclobutene-3,4-dicarboxylic acid anhy-dride, o-phenylene sulfite and o-benzoquinone and its PE spectrum is recorded. The PE spectrum and also the PE spectra of the various precursors as well as of the cyclo-pentadienone dimer are interpreted on the basis of our recently developed PERTCI method (i. e. performing large scale perturbation configuration interaction calculations in connection with selection procedures). The agreement be-tween measured and calculated ionization potentials is good. 
  Reference    Z. Naturforsch. 33a, 383—385 (1978); eingegangen am 18. Februar 1978 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0383_n.pdf 
 Identifier    ZNA-1978-33a-0383_n 
 Volume    33 
60Author    J. S. BerryRequires cookie*
 Title    On the Interaction of a Weak-R Type Ionization Front and a Contact Discontinuity  
 Abstract    A numerical solution is given to the problem of a weak R type ionization front approaching a contact discontinuity across which the density increases. During the interaction it is found that there are three possible configurations produced; the weak-R type ionization front becomes (a) weak-R type but slower for QI/QO < 1.15, (b) strong-D type for 1.15 < QI/QO < 3.4 or (c) weak-D type for QI/QO > 3.4, where the original ionization front travels through a region of initial density go and across the contact discontinuity the density becomes £>i. A fine spacial mesh length is chosen so that the structures of the resulting ionization fronts and shock waves may be identified clearly at any time. 
  Reference    Z. Naturforsch. 33a, 393—397 (1978); received December 15 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0393.pdf 
 Identifier    ZNA-1978-33a-0393 
 Volume    33 
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