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1989 (196)
81Author    M. Heckele, P. Lamparter, S. SteebRequires cookie*
 Title     
 Abstract    tr u c tu r e o f A m o rp h o u s (C o , M n) 76B 24-a n d (C o , M n) 85B 15-A llo y s by M e a n s o f X -R a y -a n d N e u tr o n -D if f r a c tio n Amorphous (COj _xMnx)85B15-(x = 0.07; 0.22; 0.39) and (Co, _xMnt)76B24-(x = 0; 0.07; 0.22) alloys were produced by melt-spinning and investigated by X-ray-and neutron-diffraction. The variation of x, i.e. the manganese concentration did not influence the X-ray intensity pattern, which suggests that no larger topological changes in the structure took place. However, using neutrons, the variation of x caused large intensity variations. These lead for large x to negative values in the total pair distribution functions g{R). From this behaviour it is concluded that cobalt and manganese cannot be mutually substituted but form a chemical short range order with preference for Co Mn-pairs compared to Mn-Mn-and Co-Co-pairs. The metal-boron-correlations are preferentially cobalt-boron-correlations. The evaluation of measured data yielded no direct boron-boron-con-tacts. 
  Reference    Z. Naturforsch. 44a, 495—503 (1989); received March 18 1989 
  Published    1989 
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 Identifier    ZNA-1989-44a-0495 
 Volume    44 
82Author    Hans SallhoferRequires cookie*
 Title     
 Abstract    y d r o g e n in E le c tro d y n a m ic s I I I . T h e H y d r o g e n S p e c tru m After a discussion of the one-component Schrödinger (1926) and the four-component Dirac (1928) representation of hydrogen it is shown that the six-component electrodynamic picture turns out to be considerably simpler and clearer. The computational effort is reduced to a fraction. 
  Reference    Z. Naturforsch. 44a, 504—506 (1989); received March 2 1989 
  Published    1989 
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 Identifier    ZNA-1989-44a-0504 
 Volume    44 
83Author    M. W. Markus, K.M T Yamada, G. WinnewisserRequires cookie*
 Title      
 Abstract    The spectrum of methyl isocyanide (CH3NC) has been measured in the region from 2148 cm" 1 to 2179 cm ~1 using a tunable diode laser spectrometer employing a newly designed signal averaging technique. The P-, Q-and R-branch lines of the v2 fundamental band have been assigned for values of J <25, K< 12. Molecular constants for the v2 state have been determined including the quartic centrifugal distortion parameters. H ig h R e s o lu tio n S p e c tr u m o f th e C H 3N C v2 F u n d a m e n ta l B a n d 1 
  Reference    Z. Naturforsch. 44a, 507 (1989); received March 10 1989 
  Published    1989 
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 Identifier    ZNA-1989-44a-0507 
 Volume    44 
84Author    S. Sh, A. Soulayman, HarfoushRequires cookie*
 Title     
 Abstract    a lc u la tio n o f th e M e ltin g C u rv e s o f s o m e A lk a li-h a lid e s w ith C s C l S tr u c tu r e a n d th e ir T h e r m o d y n a m ic P r o p e r tie s a lo n g th e s e C u rv e s The paper presents a study of three semi-empirical laws of melting. The study utilises the Im­ proved Unsymmetrized Self-Consistent Field Method (IUSCFM) for strongly anharmonic crystals with complex lattice and the energy criterion in calculating the melting curves of some alkali-halides. The energy criterion was proven correct along the melting curves particularly in the case of CsCl type of structure. The calculations of the melting curves for crystals of nine alkali-halides (KCl, KBr, KI, RbCl, RbBr, Rbl, CsCl, CsBr, Csl) are presented. The thermodynamic properties of these salts along the curves are also determined. A comparison of the calculated results and the experimental data is included. 
  Reference    Z. Naturforsch. 44a, 513—518 (1989); received October 27 1988 
  Published    1989 
  Keywords    Melting curves, Alkali-halides, Thermodynamic properties, Energy criterion, CsCl structure 
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 Identifier    ZNA-1989-44a-0513 
 Volume    44 
85Author    W. Ebeling, K. KilimannRequires cookie*
 Title    Io  
 Abstract    n iz a tio n E n e rg y a n d L evel S h if ts o f M u ltip ly C h a rg e d Io n s in N o n id e a l P la s m a s The Bethe-Salpeter equation for plasmas containing ions with higher charges is solved by pertur­ bation methods. The lowering of the ionization energy as well as the energy level shifts due to nonideality effects are calculated. It is shown that multiply charged ions lead to an essential amplification of nonideality effects. An estimate for the modification of transition rates is given. 
  Reference    Z. Naturforsch. 44a, 519—523 (1989); received February 11 1989 
  Published    1989 
  Keywords    Multiply charged ions, Ionization energy, Level shift, Lyman series, Ionization kinetics 
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 Identifier    ZNA-1989-44a-0519 
 Volume    44 
86Author    Rajkumar Roychoudhury, Manasi SenguptaRequires cookie*
 Title    G a u s  
 Abstract    s ia n A p p ro a c h to (1 + 1) D im e n s io n a l S o lito n s a t F in ite T e m p e ra tu re Soliton solutions at finite temperature have been studied using the Gaussian effective potential approach. A critical temperature Tc is obtained at which the soliton solutions cease to exist. The effective potential has also been calculated together with the Mass Gap equation. 
  Reference    Z. Naturforsch. 44a, 524—528 (1989); received March 2 1989 
  Published    1989 
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 Identifier    ZNA-1989-44a-0524 
 Volume    44 
87Author    L. C. Prasad, R. N. SinghRequires cookie*
 Title    Q u a s  
 Abstract    i-C h e m ic a l M o d e l f o r L iq u id L i-C d A llo y s The quasi-chemical model based on pairwise interactions is used to study the concentration dependent thermodynamic properties of Li-Cd liquid alloys. Special attention is given to the concentration-concentration correlation function in the long wavelength limit [Scc(O)] and the chemical short-range order parameter (CSRO). The activity, free energy of mixing, Scc(O) and CSRO are computed as functions of temperature and concentration. 
  Reference    Z. Naturforsch. 44a, 529—532 (1989); received October 19 1988 
  Published    1989 
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 Identifier    ZNA-1989-44a-0529 
 Volume    44 
88Author    KostasS. Farmakis, IoannisG. PouliosRequires cookie*
 Title     
 Abstract    h a r a c te r iz a tio n o f E le c tro d e p o s ite d M o ly b d e n u m B la c k S u r f a c e C o a tin g s Molybdenum black has been produced in thin coating form (3 pm) on prepared aluminium surfaces by the method of electrodeposition. The microstructure of the coating has been identified as one of flat irregular platelets belonging to a material which can be described as quasi-amorphous. Its chemical composition is 90 wt% MoO, • 2 H20 and 10 wt% Ni(OH)2 • Mo-black appears to be a good absorber of solar radiation. Absorbance values as high as 93% have been measured for the visible region of the solar energy spectrum. It has been identified that the coating is of semiconduct­ ing nature and that the dominant conduction mechanism is the Schottky emission mechanism. Photoelectrochemical measurements have finally provided evidence for photon-induced electro­ chemical processes at the Mo-black electrodes. 
  Reference    Z. Naturforsch. 44a, 533—537 (1989); received September 22 1988 
  Published    1989 
  Keywords    Molybdenum black, Electrodeposition, Amorphous semiconductor, Schottky emission 
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 Identifier    ZNA-1989-44a-0533 
 Volume    44 
89Author    J. Doose, A. Guarnieri, W. Neustock, R. Schwarz, F. Winther, F. HegelundRequires cookie*
 Title     
 Abstract    p p lic a tio n o f a P C -C o n tr o lle d M W -S p e c tr o m e te r f o r th e A n a ly s is o f K e te n e -D 2 . S im u lta n e o u s A n a ly s is o f V ib r a tio n a l E x c ite d S t a te s U s in g M ic ro w a v e a n d I n f r a r e d S p e c tr a D2CCO has been investigated in the first excited vibrational states of the v9, v6, and v5 vibrations. About 150 transitions have been measured partly at room temperature and partly at 360 K using a micro-and millimeter-wave spectrometer provided with an averaging system using a personal computer. Rotational and centrifugal distortion constants have been obtained for the excited states mentioned. A simultaneous least squares analysis of these MW-data with upper state combination differences obtained from FT-IR data has been carried out. Improved sets of molecular parameters have been obtained. 
  Reference    Z. Naturforsch. 44a, 538 (1989); received March 17 1989 
  Published    1989 
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 Identifier    ZNA-1989-44a-0538 
 Volume    44 
90Author    Teruo Haibara, Osamu Odawara, Isao OkadaRequires cookie*
 Title    in th e M o lte n B in a ry S y s te m ( N a , N H 4) N 0 3  
 Abstract    Relative differences in the internal cation mobilities in the molten binary system (Na, NH4)N03 have been measured by Klemm's countercurrent electromigration method at NaN03 mole fractions 0 0.3 and temperatures 433-453 K. Also the densities and electric conductivities of this system have been measured. From these data the internal cation mobilities, />N a and bSHj, were calculated. Under all accessible conditions, bNHj is greater than fcNa. The results are discussed in terms of the interaction between unlike ions and free space. I n te r n a l C a tio n M o b ilitie s 
  Reference    Z. Naturforsch. 44a, 551—554 (1989); received March 1 1989 
  Published    1989 
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 Identifier    ZNA-1989-44a-0551 
 Volume    44 
91Author    Horst-Dieter Försterling, Szilvia Murányi, Helmut SchreiberRequires cookie*
 Title      
 Abstract    In the Belousov-Zhabotinsky system bromine species of oxidation states — 1 to 5 are important for the start and for the inhibition of the autocatalytic reaction steps. Especially, the reaction of Br~ with HBr02 competes with the oxidation of Ce3+ by BrOz formed from HBrO, and HBr03. In our investigation the reaction of Br with HBr02 (solvent 1 M sulfuric acid) is followed spectroscopi-cally in a mixture of bromine and hypobromous acid, which system works as a buffer for bromide. Including experiments on the hydrolysis of Br2 and on the solubility product of AgBr in 1 M sulfuric acid solution direct information about the rate constant kl of the Br~/HBrO, reaction is obtained (fc, = 2.5 x 106 M"2 s"1 at 20 C and 4x 106 M"2 s"1 at 25°C, which values are valid in the range of 0.01 to 1 M sulfuric acid). R a te o f th e B ro m o u s A c i d -B r o m i d e R e a c tio n 
  Reference    Z. Naturforsch. 44a, 555 (1989); received March 15 1989 
  Published    1989 
  Keywords    Belousov-Zhabotinsky reaction, Bromous acid Bromide, Bromine hydrolysis, Bromate, Dual wavelength spectroscopy 
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 Identifier    ZNA-1989-44a-0555 
 Volume    44 
92Author    C. MargheritisRequires cookie*
 Title     
 Abstract    h e L iq u id P h a s e o f S u p e rio n ic C o n d u c to rs . M C S im u la tio n s o f M o lte n S ilv e r Io d id e MC simulations, in the NpT version, were carried out on molten Agl, on the basis of the literature interionic potentials proposed for the simulation of the superionic a-phase of solid Agl. A systematic analysis showed that none of the examined potentials can satisfactorily reproduce the experimental characteristics of the melt. Moreover, it has been pointed out that tests of pair potentials through simulations at constant volume can be misleading. 
  Reference    Z. Naturforsch. 44a, 567—572 (1989); received March 5 1989 
  Published    1989 
  Keywords    Interionic potentials, Monte Carlo simulation, Molten Agl 
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 Identifier    ZNA-1989-44a-0567 
 Volume    44 
93Author    N. Heineking, H. DreizlerRequires cookie*
 Title      
 Abstract    We report on our experience with the adaptation of phase correction techniques to microwave Fourier transform spectroscopy. The performance of this yet uncommon technique is based on theoretical considerations and compared to other methods. P h a s e C o r r e c tio n in M ic ro w a v e F o u r ie r T r a n s f o r m S p e c tr o s c o p y 
  Reference    Z. Naturforsch. 44a, 573 (1989); received March 17. 1989 
  Published    1989 
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 Identifier    ZNA-1989-44a-0573 
 Volume    44 
94Author    N. Heineking, M.C L Gerry, H. DreizlerRequires cookie*
 Title     
 Abstract    e u te riu m N u c le a r Q u a d r u p o le C o u p lin g in D e u te ro -Is o c y a n ic A c id The deuterium quadrupole hyperfine structure has been resolved in the 6(1, 5)-6(1, 6) transition of deutero-isocyanic acid (DNCO), and has been used to evaluate the previously undetermined coupling constant (X bb — Zee)-With the assumption of cylindrical symmetry for the deuterium quadru­ pole coupling tensor its principal values have been estimated and have been found to be in excellent agreement with a theoretical prediction. Within experimental error the "-principal quadrupole axis and the D N internuclear axis coincide. 
  Reference    Z. Naturforsch. 44a, 577 (1989); received March 17 1989 
  Published    1989 
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 Identifier    ZNA-1989-44a-0577 
 Volume    44 
95Author    -Kook Suh, K. Sugiyama, Y. Waseda, J. M. ToguriRequires cookie*
 Title      
 Abstract    The structure of molten CaO Fe20 3, with CaO content from 33 to 60 mol% was studied by means of high temperature x-ray diffraction. At higher CaO concentrations the iron atoms were found to become more and more tetrahedrally by rather than octahedrally surrounded by oxygens. The present structural information is consistent with the reported results on the viscosity of this system. 
  Reference    Z. Naturforsch. 44a, 580—584 (1989); received February 24 1989 
  Published    1989 
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 Identifier    ZNA-1989-44a-0580 
 Volume    44 
96Author    Massimo Marchi, MichaelL. KleinRequires cookie*
 Title     
 Abstract    C o m p u te r S im u la tio n S tu d y o f S u p e rc o o le d L iq u id a n d A m o rp h o u s -S o lid M e th a n o l The constant-pressure molecular dynamics technique has been used to study the structural consequences of cooling liquid methanol. We employed a periodically replicated system of 250 molecules interacting with an intermolecular potential fitted to thermodynamic properties of the liquid. Plots of the enthalpy and volume against temperature exhibit a distinct change in slope around 160 K; a feature that is identified with the onset of structural arrest, occurring on the picosecond time-scale, in the supercooled liquid. The corresponding glass transition in real methanol occurs around 103 K. The main structural feature that accompanies the structural arrest is the appearance of a splitting in the primary peak of the radial distribution function for methyl groups. This observation contrasts strongly with the behaviour of atomic systems where such splittings arise only in the second peaks of distribution functions. The calculations are discussed in the light of recent neutron scattering data on glassy methanol. 
  Reference    Z. Naturforsch. 44a, 585—590 (1989); received April 12 1989 
  Published    1989 
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 Identifier    ZNA-1989-44a-0585 
 Volume    44 
97Author    J. Waite, M. G. PapadopoulosRequires cookie*
 Title     
 Abstract    e la tio n s h ip s o f th e P o la r is a b ility w ith th e N u m b e r o f V a le n ce E le c tro n s , th e T o ta l E n e rg y a n d th e S e c o n d H y p e r p o la r is a b ility o f M e th y lb e n z e n e s The total energy and polarisability of 12 methylbenzenes have been computed by employing the CHF-PT-EB-CNDO method. The relationships between the normalized polarisability, the total energy, the second hyperpolarisability and the number of valence electrons of the studied com­ pounds are discussed. Variations in the polarisation properties induced by structural changes are also commented upon. 
  Reference    Z. Naturforsch. 44a, 591 (1989); received March 31 1989 
  Published    1989 
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 Identifier    ZNA-1989-44a-0591 
 Volume    44 
98Author    F. WintherRequires cookie*
 Title      
 Abstract    In a recent paper by Wells et al. [1] the band origins of v3 of 12C32S2 and 13C32S2 have been determined with high accuracy from heterodyne frequency mea­ surements. As mentioned in our paper on these bands [2] our spectra were calibrated with water vapour lines from [3]. This limited the accuracy of all band centers in the paper to +3 • 10"4 cm-1 (one standard error) -not allowing for any systematic error of the calibra­ tion lines, however. Addendum to: The Infrared Spectrum of C S2 in the v3 Band Region 
  Reference    Z. Naturforsch. 44a, 594 (1989); received April 1 1989 
  Published    1989 
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 Identifier    ZNA-1989-44a-0594_n 
 Volume    44 
99Author    Junko HabasakiRequires cookie*
 Title    Local Structure and O kada's Empirical Relation for the Internal Mobility of Cations in Molten Alkali Nitrates  
 Abstract    The empirical relation b. = (V -F0i)_1 Ai exp(— EJR T) for the internal mobility bt of cations i in mixtures of molten alkali nitrates, where V is the molar volume of the mixture, is compared with MD simulations. For pure LiN03 and NaNO, it is found that (V—V 0;) 1 is proportional to the concentration of oxygens in the first coordination shells of the cations /' . 
  Reference    Z. Naturforsch. 44a, 595—596 (1989); received March 6 1989 
  Published    1989 
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 Identifier    ZNA-1989-44a-0595_n 
 Volume    44 
100Author    K. H. Schweikert, F. NoackRequires cookie*
 Title      
 Abstract    The frequency dependence of the longitudinal proton spin relaxation time Tx was measured by field-cycling and standard NMR techniques in the nematic, smectic and reentrant nematic mesophases of the reentrant liquid crystal 6OCB-8OCB. The results clearly demonstrate that, in contrast to conclusions reported in the literature, the underlying relaxation mechanisms are the same for the nematic and reentrant nematic order, but different in the nematic and smectic phase. In particular, at low frequencies the nematic and reentrant samples reveal a square-root dispersion profile (T, ~ v1 2) characteristic for nematic director fluctuations, whereas the smectic samples show a dissimilar and only very narrow dispersion step. It can be attributed to a linear relaxation time increase (Tx ~ v1) expected for smectic-type order fluctuations. The experimental data are described and discussed in terms of four molecular processes, namely nematic or smectic order fluctuations, self-diffusion, rotational motions, and a resonant proton nitrogen coupling. 
  Reference    Z. Naturforsch. 44a, 597 (1989); received April 19 1989 
  Published    1989 
  Keywords    Spin relaxation Field-cycling, Liquid crystals, Reentrant nematic 
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 Identifier    ZNA-1989-44a-0597 
 Volume    44 
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