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2001[X]
121Author    S. V. Devyatkin, O. I. Boiko, N. N. Uskova, G. KaptayaRequires cookie*
 Title    Electrochemical Synthesis of Titanium Silicides from Molten Salts  
 Abstract    Presented at the NATO Advanced Study Institute, Kas, Turkey, May 4 -14, 2001. Electrochemical synthesis o f titanium silicides from chloro-fluoride melts has been investigated by thermodynamic calculation, voltammetry and electrolysis. The electrochemical synthesis of four titanium silicides (TiSi2, TiSi, Ti5Si4, Ti5Si3) was to be a one-step process, the stoichiometry of the deposited silicides being correlated with the concentration of Si and Ti ions in the melt. 
  Reference    Z. Naturforsch. 56a, 739—740 (2001); received August 20 2001 
  Published    2001 
  Keywords    Titanium silicides, Electrochemical Synthesis, Molten Salts 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0739.pdf 
 Identifier    ZNA-2001-56a-0739 
 Volume    56 
122Author    S. A. Kuznetsov, L. Rycerza, M. Gaune-Escard3Requires cookie*
 Title    Electrochemical and Thermodynamic Properties of EuC13 and EuC12 in an Equimolar NaCl-KCl Melt  
 Abstract    The electroreduction o f EuCl3 in an equimolar NaCl-KCl mixture was studied at 973 -1123 K by different electrochemical methods. This reduction of Eu(III) in NaCl-KCl melt occurs via two successive reversible steps involving transfer o f one and two electrons. The diffusion coefficients of Eu(III) and Eu(II) were measured by linear sweep voltammetry and chronopotentiometry. The values found by these methods are in a good agreement. The standard rate constants for the redox reaction Eu(III) + e~ <=> Eu(II) were calculated from cyclic voltammetry data. The sluggish kinetics of this reaction is discussed in terms o f substantial rearrangement of the europium coordination sphere. Special attention was paid to the choice of working electrodes for the study o f electrode reactions. The formal standard potentials E*E u (^ /Ba, E* eU (hr/eu and the formal redox potentials ^*Eu(ni)/Eu(ii) were determined from open-circuit potentiometry and linear sweep voltammetry data. The free Gibbs energy changes for the reaction EuC13(so1) EuCl2(SO i.) + 1/2 Cl2(g.) and the equilibrium constants o f the metal-salt reaction 2Eu(III) + Eu 3 Eu(II) were calculated. The thermodynamics of the formation o f dilute solutions of europium di-and trichloride in an equimolar NaCl-KCl melt were determined. It was shown that electrochemical transient techniques give the possibility o f the determination of the relative partial molar mixing enthalpy of europium trichloride and dichloride in NaCl-KCl melt. 
  Reference    Z. Naturforsch. 56a, 741 (2001); received August 20 2001 
  Published    2001 
  Keywords    Europium, Molten Salts, Kinetics of Electrode Reaction, Formal Standard Potentials, Mixing Enthalpy 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0741.pdf 
 Identifier    ZNA-2001-56a-0741 
 Volume    56 
123Author    Alina Wojakowska, Agata GorniakRequires cookie*
 Title    The Electrical Conductivity of Molten (Ag, C d 1/2)B r  
 Abstract    The electrical conductivity of molten (Ag, Cd1/2)Br has been determined as a function of temperature in the whole range of compositions. The resulting activation energy values and the conductivity isotherm at 850 K are compared with those of the system (Ag, C d^^C l. 
  Reference    Z. Naturforsch. 56a, 751—753 (2001); received August 20 2001 
  Published    2001 
  Keywords    AgBr, CdBr2, Molten Salts, Electrical Conductivity 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0751.pdf 
 Identifier    ZNA-2001-56a-0751 
 Volume    56 
124Author    Alena Novoselova, Vladimir Shishkin, Vladimir KhokhlovRequires cookie*
 Title    Redox Potentials of Samarium and Europium in Molten Lithium Chloride  
 Abstract    The samarium (III)/(II) and europium (III)/(II) redox potentials in molten lithium chloride were measured using the direct potentiometric method in the temperature range from 923 to 1094 K. Glassy carbon was used as the indifferent working electrode, and the standard chlorine electrode as a reference. The total concentration of rare-earth chlorides dissolved in molten lithium chloride did not exceed 4.5 mol%. 
  Reference    Z. Naturforsch. 56a, 754—756 (2001); received August 20 2001 
  Published    2001 
  Keywords    Molten Salts, Redox Potentials, Samarium Chlorides, Europium Chlorides, Lithium Chloride 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0754.pdf 
 Identifier    ZNA-2001-56a-0754 
 Volume    56 
125Author    C. Christov, S. Gabriel3, B. Atanasov, J. Fleischhauer3Requires cookie*
 Title    Calculation of the CD Spectrum of Class A /3-Lactamase from Escherichia coli (TEM-1)  
 Abstract    The Circular Dichroism (CD) spectrum o f /3-lactamase from Escherichia coli (TEM-1) has been calculated with the matrix method on the basis of the x-ray diffraction structure. All known transitions in the peptide and side-chain groups, especially the aromatic and disulfide groups have been included. The calculations were performed with and without the tryptophan (Trp) residues. Rotational strengths calculated with the matrix method were combined with Gaussians to generate the CD spectrum. The calculated spectrum reproduces the signs and approximate magnitudes of the CD bands rather w ell only when the trytophan side chains are included. However, the experimental negative double band at 208 and 222 nm, which is characteristic for a-helices, is absent in the calculated spectrum. 
  Reference    Z. Naturforsch. 56a, 757 (2001); received September 12 2001 
  Published    2001 
  Keywords    /3-Lactamase, CD-spectrum, Matrix Method 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0757.pdf 
 Identifier    ZNA-2001-56a-0757 
 Volume    56 
126Author    S. Volkov, N. Tumanova, S. Kothetova, N. BuryakRequires cookie*
 Title    The Polysurface Mechanism of Ta and Ti Anodic Dissolution in Low-Temperature Carbamide-NH4CL Melt  
 Abstract    In this work the peculiarities o f the electrochemical dissolution of tantalum and titanium in carbamide containing low temperature melts were studied. 
  Reference    Z. Naturforsch. 56a, 761—763 (2001); received August 8 2001 
  Published    2001 
  Keywords    Carbamide, Tantalum, Titanium, Electrochemistry, Passivation 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0761.pdf 
 Identifier    ZNA-2001-56a-0761 
 Volume    56 
127Author    K. S. Suresh3, K. P. Rameshb, C. Raghavendra Rao3, J. RamakrishnabRequires cookie*
 Title    Pressure Dependence of the Chlorine NQR in Three Solid Chloro Anisoles  
 Abstract    The 35C1 Nuclear Quadrupole Resonance (NQR) frequency (V q) and spin lattice relaxation time (T{) in the three anisoles 2,3,4-trichloroanisole, 2,3,6-trichloroanisole and 3,5-dichloroanisole have been measured as a function of pressure upto 5.1 kbar at 300 K, and the data have been analysed to estimate the temperature coefficients of the NQR frequency at constant volume. All the three com­ pounds show a non linear variation of the NQR frequency with pressure, the rate of which is positive and decreases with increasing pressure. In case of 3,5-dichloroanisole the value becomes negative in the higher range of pressure studied. The spin lattice relaxation time T{ in all the three compounds shows a weak dependence on pressure, indicating that the relaxation is mainly due to the torsional motions. 
  Reference    Z. Naturforsch. 56a, 764—772 (2001); received July 19 2001 
  Published    2001 
  Keywords    NQR, 35C1, Frequency, Spin-lattice Relaxation Time, Torsional Motion, Pressure and Temperature Dependence, 3,5-dichloroanisole, 2,3,4-trichloroanisole, 2,3,6-trichloroan­ isole 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0764.pdf 
 Identifier    ZNA-2001-56a-0764 
 Volume    56 
128Author    A. Chrissanthopoulos3, C. Pouchan3, G. N. Papatheodorou5Requires cookie*
 Title    Structural Investigation of Vanadium -Sodium Metaphosphate Glasses  
 Abstract    Paper presented a t the NATO A dvanced Study Institute, M ay 4-1 4 , 2001 (Kas, Turkey) The structure of the glass forming system (V20 5)x -(Na20 • P205)(1_^), (jc = 0-0.4), has been inves­ tigated using Raman spectroscopy. The stretching vibrations of various phosphate groups, connected to phosphorus or vanadium atoms, have been assigned. Variation o f the composition leads to structural changes where the sodium metaphosphate -P-O-P-chains break and then reconnect with the oxovana-dium units forming a -V-O-P-network structure. 
  Reference    Z. Naturforsch. 56a, 773—7 (2001); received August 8 2001 
  Published    2001 
  Keywords    Vanadium, Phosphates, Vanadium Glass, Raman Spectroscopy, Metaphosphates 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0773.pdf 
 Identifier    ZNA-2001-56a-0773 
 Volume    56 
129Author    Noriaki Okubo, Mutsuo Igarashi3Requires cookie*
 Title    Relaxation of 121Sb NQR in Antimony Trichloride due to Raman Process  
 Abstract    The spin-lattice relaxation times of 121Sb nuclear quadrupole resonance in SbCl3 have been measured from 4.2 K to the m. p., 346 K. The result is analyzed with a theory of the Raman process based on co­ valency and discussed in comparison with the previous result for Cl nuclei. 
  Reference    Z. Naturforsch. 56a, 777 (2001); received August 21 2001 
  Published    2001 
  Keywords    SbCl3, 121Sb-NQR, Relaxation Times, Raman Process, Covalency 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0777.pdf 
 Identifier    ZNA-2001-56a-0777 
 Volume    56 
130Author    S. A. Markarian, A. S. Galstian, M. Stockhausen3Requires cookie*
 Title    A Dielectric Relaxation Study of Diethylsulfoxide/ Tetrachloromethane Binary Mixtures  
 Abstract    The dielectric spectra o f diethylsulfoxide (DESO)/tetrachloromethane mixtures have been measured from 0.5 to 72 GHz at 20 °C. On the basis of the relation between the relaxation time and the DESO concentration a complex formation between DESO and tetrachloromethane is suggested. 
  Reference    Z. Naturforsch. 56a, 785—7 (2001); received September 27 2001 
  Published    2001 
  Keywords    Association, Dielectric Spectroscopy, Liquids 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0785.pdf 
 Identifier    ZNA-2001-56a-0785 
 Volume    56 
131Author    Giorgio Concas, Francesco Congiu, Giorgio Spano, Marco Bettinelli3, Adolfo Speghini3, ColinD. FlintbRequires cookie*
 Title    Investigation of Structural Questions on Europium Compounds by Means o f 151 Eu Mössbauer Spectroscopy  
 Abstract    151 Eu Mössbauer spectroscopy permits the determination of the symmetry of the site in which Eu is accommodated. It has been shown that the 151Sm F3 source can be considered a monochromatic source. This source was used to measure the line width of Eu3+ in a site with cubic symmetry, i. e. in a Cs2NaEuCl6 crystal. The isomer shift of commercial compounds used as standards (anhydrous EuF3 and EuS) was also measured. In the case of Cs2N aE u(N 02)6 hexanitritoelpasolite the trivalent europium ion is accommodated in a site with perfect cubic symmetry. In E u(P 03)3 crystalline metaphosphate, the rare earth is located in a site which appears to be distorted with respect to cubic symmetry; this site has no threefold or fourfold symmetry axis. 
  Reference    Z. Naturforsch. 56a, 789—793 (2001); received October 29 2001 
  Published    2001 
  Keywords    Elpasolites, Oxides, 15lEu Mössbauer Spectroscopy 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0789.pdf 
 Identifier    ZNA-2001-56a-0789 
 Volume    56 
132Author    FalkH. KoenemannRequires cookie*
 Title    Unorthodox Thoughts about Deformation, Elasticity, and Stress  
 Abstract    The nature of elastic deformation is examined in the light of the potential theory. The concepts and mathematical treatment of elasticity and the choice o f equilibrium conditions are adopted from the mechanics o f discrete bodies, e. g., celestial mechanics; they are not applicable to a change o f state. By nature, elastic deformation is energetically a Poisson problem since the buildup of an elastic potential implies a change of the energetic state in the sense of thermodynamics. In the Euler-Cauchy theory, elasticity is treated as a Laplace problem, implying that no change of state occurs, and there is no clue in the Euler-Cauchy approach that it was ever considered as one. The Euler-Cauchy theory of stress is incompatible with the potential theory and with the nature of the problem; it is therefore wrong. The key point in the understanding of elasticity is the elastic potential. 
  Reference    Z. Naturforsch. 56a, 794—808 (2001); received January 25 2001 
  Published    2001 
  Keywords    Potential Theory, Elasticity, Stress, Poisson Equation, Cauchy Theory 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0794.pdf 
 Identifier    ZNA-2001-56a-0794 
 Volume    56 
133Author    Zhenya YanRequires cookie*
 Title    Abundant New Exact Solutions of the Coupled Potential KdV Equation and the Modified KdV-Type Equation  
 Abstract    Exact solutions of nonlinear evolution equations (NLEEs)in soliton theory and their applications are studied. A powerful method is established to search for exact travelling wave solutions of NLEEs. We chose the coupled potential KdV equation and modified KdV-type equations presented by Foursov to illustrate the approach with the aid of Maple. As a result, eight families of exact solutions of the coupled potential KdV equation and nine families of exact solutions of the modified KdV-type equations are obtained, which contain new kink-like soliton solutions, kink­ shaped solitons, bell-shaped solitons, periodic solutions, rational solutions and singular solitons. The properties of the solutions are shown in figures. 
  Reference    Z. Naturforsch. 56a, 809—815 (2001); received June 25 2001 
  Published    2001 
  Keywords    Coupled Potential KdV Equation, Modified KdV-type Equation, Soliton Solutions, Periodic Solutions, Rational Solutions 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0809.pdf 
 Identifier    ZNA-2001-56a-0809 
 Volume    56 
134Author    Zhenya YanRequires cookie*
 Title    Abundant New Multiple Soliton-like Solutions and Rational Solutions of the (2+l)-Dimensional Broer-Kaup Equation  
 Abstract    In this paper we firstly improve the homogeneous balance method due to Wang, which was only used to obtain single soliton solutions o f nonlinear evolution equations, and apply it to (2 + 1)-dimensional Broer-Kaup (BK) equations such that a Backlund transformation is found again. Considering further the obtained Backlund transformation, the relations are deduced among BK eqautions, well-known Burgers equations and linear heat equations. Finally, abundant multiple soliton-like solutions and infinite rational solutions are obtained from the relations. 
  Reference    Z. Naturforsch. 56a, 816—824 (2001); received June 25 2001 
  Published    2001 
  Keywords    (2+l)-dim ensional Broer-Kaup equation, Backlund Transformation, Burgers Equation, Soliton Solution, Rational solution 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0816.pdf 
 Identifier    ZNA-2001-56a-0816 
 Volume    56 
135Author    P. P. Nath, S. Sarkar, P.S R Krishna3, R. N. JoarderRequires cookie*
 Title    Molecular Conformation and Structural Correlations of Liquid D-terf-Butanol at Room Temperature by Neutron Diffraction  
 Abstract    An analysis o f neutron diffraction data o f liquid deuterated terr-butanol at room temperature to determine its molecular conformation is presented. Being a big molecule o f 15 sites, the analysis is tricky and needs careful consideration. The resulting molecular parameters are compared with those obtained from other experimental data analysis and model calculations. The information about the intermolecular structural correlations, hydrogen-bonded molecular association in partcular is also obtained from the diffraction data analysis. -PACS number: 61.25 
  Reference    Z. Naturforsch. 56a, 825—831 (2001); received August 13 2001 
  Published    2001 
  Keywords    Conformation, Structure, Correlation, D-terr-Butanol, Neutron Diffraction 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0825.pdf 
 Identifier    ZNA-2001-56a-0825 
 Volume    56 
136Author    S. B. Gadzuric, I. J. Zsigrai, R. M. Nikolic3Requires cookie*
 Title    Thermodynamics of Lead(II) Halide Complex Formation in Calcium Nitrate Tetrahydrate -Acetamide Melts  
 Abstract    The complex formation between lead(II) ions and chloride and bromide ions in melts of C a(N 03) 2 • 4 H20 • aCH3CONH2 has been studied at different temperatures between 30 and 70 °C. The formation constants of the complexes PbX+ and PbX2 (X = Cl, Br) were determined from em f measurements by means of Ag/AgX electrodes. The dependence of the formation constants for PbCl+ on the solvent melt composition has been analysed. The thermodynamic parameters A and A Sn for PbX+ complex formation have been estimated. The parameters are compared with the literature data for the same process in dilute aqueous solutions and in some hydrated and anhydrous salt melts. 
  Reference    Z. Naturforsch. 56a, 832—836 (2001); received August 20 2001 
  Published    2001 
  Keywords    Lead(II) Halide Complexes, Acetamide, Calcium Nitrate Tetrahydrate 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0832.pdf 
 Identifier    ZNA-2001-56a-0832 
 Volume    56 
137Author    Alena Novoselova, Vladimir Khokhlov, Vladimir ShishkinRequires cookie*
 Title    Thermodynamic Characteristics of Samarium and Europium Chlorides in Molten Alkali Metal Chlorides  
 Abstract    The formal standard redox potentials of samarium (III)/(II) (EZmi+/ Smi+) and europium (III)/(II) (• £, £u3+/eu2+) *n molten alkali metal chlorides were measured potentiometrically against a reference chlorine electrode. The Gibbs energy changes and equilibrium constants for the reaction LnCl2(D + V2 Cl2(g) LnCl3(I) were calculated for the salt systems studied. The effect o f the cationic composition of the melt-solvent on the above thermodynamic characteristics is also reported. 
  Reference    Z. Naturforsch. 56a, 837—840 (2001); received August 20 2001 
  Published    2001 
  Keywords    Thermodynamic Stability, Rare Earth Chlorides, Molten Alkali Metal Chlorides, Redox Potentials, Gibbs Energy Changes 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0837.pdf 
 Identifier    ZNA-2001-56a-0837 
 Volume    56 
138Author    M. Brozis3, J. R. Heldtb, J. Heldt3Requires cookie*
 Title    Experimental and Theoretical Determination of Electronic State Energies of Naphthanilides  
 Abstract    Experimental absorption spectra of a -and /3-naphthanilide derivatives in the vapour phase and in MCH solution are interpreted on basis o f calculations performed using the INDO/S-CI method. The ground state geometries have been optimised with the PM3 parameterisation method. The calculated values of the lowest triplet state T { as well as energy differences of the Tj —► Tn transitions have been compared with measured data determined from the phosphorescence and picosecond transient absorption spectra. For SQ —► Sn and T x — Tn transitions, a good agreement is noticed between the experimental and calculated energy values. An additional band observed in the total luminescence spectrum at 77 K, is interpreted as due to the emission of the double H-bonded imidol dimer formed in the excited state. -PACS: 31.70 Dk, 33.50 Dg 
  Reference    Z. Naturforsch. 56a, 841—848 (2001); received August 27 2001 
  Published    2001 
  Keywords    Naphthanilides, Absorption, INDO/S Calculations, Luminescence Spectrum 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0841.pdf 
 Identifier    ZNA-2001-56a-0841 
 Volume    56 
139Author    Thom As KrügerRequires cookie*
 Title    When is a Statistical Operator Separable? -A Comparison of Different Definitions  
  Reference    Z. Naturforsch. 56a, 849 (2001) 
  Published    2001 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0849.pdf 
 Identifier    ZNA-2001-56a-0849 
 Volume    56 
140Author    Wen-Chen Zhenga, Shao-Yi Wua, H. D. Ui-Ning, Ong3Requires cookie*
 Title    Studies of Zero-field Splitting and its Pressure and Stress Dependence for Ni2+ in La2Mg3(N 03)12 * 24 H20 Crystal  
  Reference    Z. Naturforsch. 56a, 855 (2001) 
  Published    2001 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0855.pdf 
 Identifier    ZNA-2001-56a-0855 
 Volume    56 
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