bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Composition and Thermochemistry of Tin(II), Lead(II), and Scandium(III) Iodide Vapours
Authors: Hilpert K. , Bencivenni L. , Saha B. 
Published: July 2012

AbstractThe vaporization of tin(II), lead(II), and scandium(III) iodide was studied by high‐temperature mass spectrometry with a Knudsen cell. The monomer and dimer molecules (SnI2)i(g), (PbI2)i(g), and (ScI3)i(g) (i = 1,2) were identified. Enthalpies and entropies of dimerization, equilibrium partial pressures as well as enthalpies and entropies of sublimation were evaluated for the gaseous molecules. Their molecular parameters and the thermodynamic functions computed from them are given. Appearance potentials were determined for the various ions observed upon vaporizing the three different metal iodides.
On the Conductivity of Polycrystalline Materials
Authors: Maier Joachim 
Published: July 2012

AbstractExpressions for the conductivity and impedance of polycrystalline materials are given for a greatly simplified grain distribution topology. We include not only contributions from the bulk and the proper grain boundary, but also series and parallel contributions from the space charge regions surrounding the grain boundaries. The relations obtained are applied to conductance measurements of bicrystalline and of ceramic ionic conductors (silver halides). ‐ It is shown that the space‐dependent grain boundary conductivity can be taken account of to a first approximation by introducing effective charge carrier concentrations and an effective width, and thus normal resistor‐elements. The experiments give evidence for both the presence of highly conductive space charge layers adjacent to the grain boundaries (manifesting in the high frequency impedance semi‐circle) and the presence of less conductive core regions (manifesting in the low frequency circle) in the silver halides.
“Ordered” Distribution of Ionic Micelles in Dilute Solutions of Alkyltrimethylammonium Chloride as Studied by Small‐Angle X‐ray Scattering
Authors: Ishii Yasuo , Matsuoka Hideki , Ise Norio 
Published: July 2012

AbstractThe solutions of ionic micelles of dodecyl‐, tetradecyl‐ and hexadecyl‐trimethylammonium chlorides were studied by small‐angle X‐ray scattering (SAXS). The SAXS curves showed a single, broad peak. The interference functions S(Q) were obtained from the scattering curves. The radial distribution function g(r) was calculated from S(Q) and the distances between nearest neighboring micelles were evaluated. The intermicellar distances (rm) evaluated from g(r) were close to the average distance calculated by assuming a uniform distribution of the micelles throughout the solution. This fact indicates that the intermicelle attractive force through the intermediary of counterions was weak, because the number of charges on the micelles was small. A difference between rm and the Bragg spacing calculated from the overall intensity of scattered X‐ray was noticed but it was not large enough to invalidate our previous interpretation that the Bragg spacing is an approximate measure of the ordered structure. By taking into account the paracrystalline distortion, the lattice factor Z(Q) was calculated. Excellent agreement was obtained with the structure factor S(Q) for a face‐centered cubic lattice structure when the distortion factor was assumed to be about 0.2. The number of peaks of the lattice factor decreased with increasing distortion factor. This suggests the incorrectness of the often expressed view that the single broad peak is not reminiscent of some kind of ordering: in this view the large distortion, which exists in solutions and at ambient temperatures, has been overlooked.
Time Delayed Two Photon Processes: II. Duschinsky Mixing Effects
Authors: Cribb Peter H. , Brickmann Jürgen 
Published: July 2012

AbstractTime delayed two photon processes via a real nonstationary intermediate state are studied within a two dimensional model approach. Therein the molecular Born‐Oppenheimer surfaces are modelled by displaced, distorted and rotated harmonic oscillator potentials and the photon transitions are treated within the Condon approximation. The mode rotation (Duschinsky effect) leads to a strong mode selectivity of the two photon transition probability as a function of rotational angles and photon delay times.
Roughening of Solid Surfaces
Authors: Rys Franz S. 
Published: July 2012

AbstractThe interface roughening phenomenon is formulated in terms of a statistical model of thermally created atomic steps. The simple case of a length‐proportional energy is equivalent to known roughening models featuring an infinite‐order roughening phase transition with an exponentially diverging correlation length and interface thickness. If, in addition, a step bending energy is included which is different for up‐ and down‐steps, the sharp roughening transition is destroyed and the correlation length and the interface thickness remain finite Hence, in this case, a roughening or surface melting transition is absent. Some estimates on the observability of this result, which has consequence, e.g. for the structural behaviour of solid surfaces and on the crystal growth mechanism, are made.
N2 Adsorbate States on Fe Films between 77 K and 273 K
Authors: Wedler G. , Borgmann D. , Alter W. , Witan K. 
Published: July 2012

AbstractThe molecular adsorption of nitrogen on Fe films was studied between 77 K and 273 K. By means of a combined measurement of adsorption isotherms, changes in resistance, changes in work function and replacement processes using 14N2 and 15N2 it was possible to determine the regimes of the α‐, γ‐, and δ‐states. Films annealed at about 320 K exhibit an adsorption behaviour very similar to that of Fe(111) single crystal surfaces.
A 7 × 7 → 2 × 7 Phase Transition of Au Overlayers on Ni(110) Surface
Authors: Mcrae E. G. , Maiic R. A. 
Published: July 2012

AbstractWhen a Ni‐0.8% Au alloy is annealed at temperatures above 400 °C, Au segregates at the Ni(110) surface to form an overlayer providing 1.0 ± 0.05 monolayer coverage [1]. Low energy electron diffraction (LEED) showed that the surface periodicity is 7 × 7 at room temperature and 2 × 7 at temperatures above 340 ± 10°C. The 7 × 7 → 2 × 7 transition was observed with a novel LEED system employing a position‐sensitive detector to make digital records of LEED patterns. The transition was found to be abrupt and to display marked hysteresis. The results have been interpreted as follows on the basis of structural models of the overlayer inferred from LEED and low energy ion scattering observations on the 7 × 7 surface [1]. Most os the Au atoms in the 7 × 7 overlayer form close‐packed zigzag chains along the [110] semi‐channels provided by the Ni(110) surface. Sets of three Au atoms from adjacent semi‐channels combine in hexagonal formations, each of which is capped by an extra Au atom. The mismatch stresses that would result from unlimited extension of this close‐packed Au‐atom arrangement are relieved by interruptions of the zig‐zag sequences to form antiphase boundaries parallel to [001]. The 2 × 7 periodicity results if the zig‐zag sequences are uninterrupted. The 7 × 7 → 2 × 7 transition involves the translation of alternate rows of Au atoms in the [001] and [001] directions by about half the Au‐Au neighbor distance. The geometry is such that the transition could be driven by a small lateral expansion of the Au overlayer relative to the Ni(110) surface.
Isomerizations of the Nitromethane Radical Cation in the Gas Phase
Authors: Egsgaard Helge , Carbea Lars , Elbel Susanne 
Published: July 2012

AbstractThe concurrent isomerizations of the nitromethane radical cation to aci‐nitromethane and methylnitrite isomers, respectively, has been established based on metastable ion studies and collision activation mass spectrometry. The energy diagram for the ionized nitromethane/aci‐nitromethane tautomeric system has been determined; the aci‐nitromethane tautomer was found to be the more stable species by ca. 0.95 eV. Attempts to generate the neutral gaseous aci‐nitromethane tautomer by low pressure pyrolysis are summarized.
Interfacial Phenomena of Polycrystalline Mg‐Doped p‐Type Iron(III) Oxide Photoelectrodes
Authors: Tinuemans A. H. A. , Koster T. P. M. , Mackor A. , Schoonman J. 
Published: July 2012

AbstractThe small‐signal a.c. response of photoelectrochemical (PEC) cells with Mg‐doped α‐Fe2O3 photocathodes has been studied in the range 10−2 to 104 Hz. A non‐linear least‐squares analysis of the complex admittance/impedance data leads to a detailed equivalent circuit for the cell. The capacitance data have been employed to construct Mott‐Schottky plots. For a p‐type Fe2O3: Mg (1 at.%) electrode the flat‐band potential Vfb in 0.1 M carbonate buffer (pH = 10) is +2.2 V vs. SCE.
Reflection Spectra of Fluid Sulphur in the Sub‐ and Supercritical Region
Authors: Tamura K. , Seyer H. P. , Hensel F. 
Published: July 2012

AbstractThe dielectric dispersion of fluid sulphur has been investigated, for the first time, by means of normal incident reflectivity measurements in the range 0.5–6.0 eV over the entire liquid vapor range at temperatures between 120°C and 1100°C and at pressures between 20 bar and 500 bar. The optical response functions ε1(ω) and ε2(ω) have been derived from the reflectivity spectra by means of a modified Kramers‐Kronig analysis. The reported measurements give useful information about the electronic structure of fluid sulphur. The polymerization transition (159°C) shifts the first optical absorption towards lower absorption energy by about 0.7 eV. In the supercritical fluid at low densities distinct bands can be observed for S3, S4 and S2. As the density is increased, these bands merge to form the optical edge of the dense fluid.
Thermodynamics and Reactivity in II—VI/III—VI‐Systems
Authors: Bredol Michael , Leute Volkmar 
Published: July 2012

AbstractRecent investigations in the systems Ga2Te3/CdTe and Ga2Se3/CdSe have shown, that some quasibinary II—VI/III—VI‐systems may possess an ordered phase as well as a thermodynamical miscibility gap. Therefore in these systems the interaction coefficient for the calculation of the excess enthalpy must be strongly concentration‐dependent, since ordering and demixing are requiring interaction coefficients of opposite sign. The thermodynamical miscibility gap in the region of non‐ordered solid solutions of II—VI‐and III—VI‐chalcogenides can be described by a regular model, which leads to good agreement with experimental data. The free enthalpy of the ordered phase is approximated by a very simple model, that takes into account an additional enthalpy contribution by the ordering process. After the evaluation of the phase diagram by minimizing the free enthalpy the calculations are compared with experimental results.
Anorganische Pigmente: Disperse Festkörper mit technisch verwertbaren optischen und magnetischen Eigenschaften
Authors: Winter Gerhard 
Published: July 2012

AbstractThe great importance of inorganic pigments arises from the fields of information, safety technology, surface protection, and creation of a colourful environment, whereas the economic reach is underlined by a world production of approx. 4 million to per year.—For a controlled synthesis of technologically relevant pigmentary properties it is necessary, starting from solid matters selected by physico‐chemical criteria, to take preparative measures which interfere in the chemistry of solid matters and of the pigment/binder interface and allow—by controlling the particle size and particle size distribution—the desired optical and magnetic properties to be optimized. Such measures have to be supported by fixing an optimum degree of dispersion in the binder.—Among the numerous pigments presently being used, TiO2 has been chosen as a representative of scattering white pigments. Scattering and absorbing colour pigments are exemplified by cadmium sulpho‐selenides, oxide pigments and mixed oxide pigments. Moreover the paper gives an insight into the production and action of magnetic pigments as well as a survey of further pigment groups.
Reversible Reduktions‐ und Reoxidationsprozesse des Typs ABO3 ⇆ ABO3‐X an Perovskitischen Metalloxiden
Authors: Reller Armin 
Published: July 2012

AbstractStructural reaction mechanisms as well as concomitant compositional and morphological changes of reversible reduction/reoxidation processes of perovscitic metal oxides are discussed. The results are based on studies by means of thermal analysis, light and electron microscopy as well as X‐ray diffraction.
Mass Transport in Aqueous Zinc Chloride‐Potassium Chloride Electrolytes
Authors: Leaist Derek G. 
Published: July 2012

AbstractConductimetric and diaphragm cell techniques have been used to measure ternary diffusion coefficients for aqueous zinc chloride‐potassium chloride solutions at 25°C. At low concentrations where Zn2+ is the major zinc‐transporting species, the diffusion‐induced electric field along zinc chloride concentration gradients drives large co‐current flows of potassium chloride. In concentrated solutions where a large proportion of zinc diffuses as anionic ZnCl−3 and ZnCl2‐4 complexes, flow of zinc chloride generates counterflow of potassium chloride. If a sharp zinc chloride gradient is formed in an otherwise uniform solution of potassium chloride, coupled diffusion can concentrate potassium ions within the diffusion boundary. Equations are developed to predict multicomponent transport coefficients for zinc chloride
in supporting electrolytes.
Ein Quecksilberporosimeter hoher Präzision zur Charakterisierung mineralischer Stoffe
Authors: Becker R. , Lentz H. , Hinze E. , Nover G. , Will G. 
Published: July 2012

AbstractA discription is given of a mercury porosimeter which can be operated at pressures from 0.1 bar up to 2.3 kbars. The corresponding pore radii cover the values from 3.2 nm up to 7 · 104 nm. Using a sample volume of 25 cm3, the resolution is in the order of 6 mm3.—This porosimeter yields information for the characterization of mineralogical solids by porosity measurement and deduction of the pore radii distribution. The interpretation of these results shows the possibility of a quantitative description of the compaction of powder materials. For some selected rock samples it was possible to find a correlation between the pore radii distribution and the degree of hydrothermal alteration (Gneiss sample) and the extraction depth resp. (Granite sample). The results for a kaolinite sample demonstrate that a careful interpretation of these measurements yields information on the geometry of the pore structure. This could be proven independently by scanning electron microscopy pictures.
Reactions in Disordered Media, Modelled Through Hierarchical Structures
Authors: Blumen A. , Zumofen G. , Klafter J. 
Published: July 2012

AbstractWe use ultrametric spaces to model the energetic disorder found in amorphous systems such as glasses or mixed molecular crystals. Ultrametric spaces (UMS) have a particularly simple barrier structure which allows to monitor the diffusion of particles under temperature‐activated jumps, and to study their reaction behavior. We obtain forms which differ from the results of the simple kinetic scheme. As also found experimentally, the time development of pseudounimolecular (A + B → 0, A0 < B0) reactions on UMS often follows stretched exponential forms à la Kohlrausch‐Williams‐Watts, whereas strictly bimolecular (A + B < 0; A0 = B0) reactions display a wide variety of algebraic decays. Furthermore, the reaction patterns are temperature‐dependent, and at low temperatures reveal features of the underlying structure. These results contrast with the standard kinetic behavior which consists in either exponential time dependences (for unimolecular) or 1/t forms (for bimolecular reactions).
Enthalpic Behaviour of Sodium Deoxycholate in Pure Water and in Water‐Urea Solutions at 25°C
Authors: Sesta Bianca , Pandolfi Pietro 
Published: July 2012

AbstractThe heats of dilution and apparent molal heat contents of sodium deoxycholate have been measured in water and in 2.5 molal urea aqueous solution at 25°C by microcalorimetry. The critical micellar region of the bile salt in water‐urea, has been identified by conductometric methods. The solute concentrations ranged from zero to about 0.4 mol · 1−1. A strict analogy has been found between the binary system, deoxycholate‐water, and the ternary system, deoxycholate‐urea‐water, except for a general shift of the critical phenomena toward the higher concentrations observed for the solutions containing urea.—Below the critical region, the enthalpic behaviour of deoxycholate conforms to the features expected for 1:1 organic electrolytes. Approaching the critical concentration, additional enthalpic effects, parallel to the dilution ones, influence the calorimetric trend of the investigated bile salt. These have been correlated with processes of molecular self‐association of the solute, similar to the micellization phenomena occurring for other surfactants.—Above the first critical concentration range, the concentration dependence of the relative molal heat content of deoxycholate, both in water and in water‐urea, is very peculiar and can be assumed as a confirmation of a multistage aggregation of the solute.
Semiconduction in the Liquid Tl—SbTlX3 System (X:Te, Se)
Authors: Uemura O. , Matsuda H. , Satow T. 
Published: July 2012

AbstractThe electrical conductivity, the magnetic susceptibility, and the thermoelectric power of the liquid Tl—SbTlTe3 and Tl—SbTlSe3 systems have been obtained as a function of temperature and composition from near the liquidus temperature up to about 1200 K. The telluride system exhibits a sharp minimum in electrical conductivity and a maximum in diamagnetic susceptibility around the composition of 80 mol% Tl. On the other hand, in the selenide system the conductivity changes little up to 66.7 mol%Tl(SbTl3Se3), and it rapidly increases with increasing Tl content above that stoichiometric composition. The thermoelectric power of both systems shows a change in sign around the respective compositions. The electronic properties of these liquid systems are discussed in the light of current transport theories employed in the amorphous and liquid semiconductors.
Kinetics of the Reaction of Atomic Fluorine with H2S and Elementary Reactions of the HS Radical
Authors: Schönle G. , Rahman M. M. , Schindler R. N. 
Published: July 2012

AbstractThe reaction of H2S with atomic fluorine (1) has been studied in a discharge‐flow system at 298 K to generate HS radicals for kinetic investigations. Mass spectrometric detection with single ion counting was employed. The rate constantk(1) was obtained from the rate of H2S consumption under the condition [H2S] << [F]0magnified imageIt has been shown that the reaction (1) provides a clean source of HS radicals. From the disappearance of HS radicals upon addition of reactants and the formation of products rate constants for the following reactions have been determined:magnified imageThe reaction of HS with O2 was also studied but it is too slow at room temperature to be followed with the present set up.
Laser raman studies on the conformation and interactions of DNA in crystals an in solution
Authors: Peticolas W. L. , Patapoff T. W. , Wang Y. , Thomas G. A. 
Published: July 2012

AbstractA laser microscope has been designed and constructed that permits the obtaining of polarized laser Raman spectra from microcrystals of deoxyoligodeoxynucleotides (short pieces of DNA). By comparing the Raman spectra obtained from single crystals where the DNA conformation is known from X‐ray diffractions experiments with crystals whose DNA conformation is unknown it is possible to obtain the secondary structure of a large number of oligonucleotides as a function of their base sequence. Furthermore, by comparing the Raman spectra of DNA in the crystal with that in solution one can see changes between the crystal and solution conformation. In this way important new information about the relation between base sequence and the environmentally induced polymorphism in DNA can be deduced. It is found that small but significant changes in the Raman spectra of the dodecamer, d(CGCGAATTCGCG) upon going from the crystal to solution or upon complexing with the restriction enzyme, Eco R1. These changes are interpreted in terms of differences in the conformation of the DNA in each of these environments.
Resonance CARS spectroscopy of bile pigments from photosynthetic antennas
Authors: Baumann F. , Schneider S. , Gege P. , Fischer R. , Siebzehnrübl S. , Scheer H. 
Published: July 2012

AbstractResonance‐enhanced CARS spectra of various biliproteins (PBS**), PC**) and its β‐subunit, APC**)) from the cyanobacterium Mastigocladus laminosus are presented. It is concluded that upon desaggregation of the whole antenna complex (PBS) into trimeric APC and PC and of PC into its subunits the microheterogeneity of the chromophores increases. APC spectra recorded with different pump wavelengths show that one chromophore in APC adopts an extended, the other one a non‐extended geometry.
Wave‐guide spectroscopy of biological material
Authors: Braun H. P. 
Published: July 2012

AbstractLight propagation along an optical wave‐guide is subject to the condition of transverse resonance, i.e. a relationship for the optical phases the light experiences when propagating along the light guiding structure. The guided light wave monitors any deviation from the resonance as a change in the transmitted light intensity. Ultra‐thin wave‐guides exhibit a high sensitivity for changes in the refractive indexes because the phase deviation from resonance is compared to the already minute optical phase of the film. This method applies to absorption spectroscopy with thin films; to the study of transport phenomena in ultra‐thin membranes and to optical signal transduction in chemical and biochemical sensors.
Elementary reactions of fluorine atoms with benzene, toluene, p‐xylene and etylbenzene
Authors: Ebrecht J. , Hack W. , Wagner H. Gg. 
Published: July 2012

AbstractThe rate constants of the reactions of fluorine atoms with benzene, toluene, p‐xylene and ethylbenzene were studied in a discharge flow reactor at room temperature and low pressure. — The aromatic compounds R were followed under pseudo first order conditions ([R]0 ≪ [F]) by mass spectrometry (MS). The rate constants. F + C6H6 k1 (296 K) = (3.0 ± 0.7). 1013 cm3/mol·s (1). F + C6H5CH3 k2 (296 K) = (4.0 ± 0.8). 1013 cm3/mol·s (2). F + C6H4(CH3)2 k3 (296 K) = (4.2 ± 0.6). 1013 cm3/mol·s (3). F + C6H5C2H5 k4 (296 K) = (4.5 ± 0.6). 1013 cm3/mol·s (4).were obtained. — The products of reaction (1) were C6H5F (80%) and HF (< 8%) and those of reaction (2) were C‐H‐F (50%), C6H5F (20%) and HF (20%). For reaction (3) the exchange mechanism is dominant, C7H7F, C8H9F (65%), and the abstraction contributes 35% (HF). In reaction (4) the abstraction is dominant (HF (50%)) with an exchange pathway of 50% C6H5F and C8H9F.
Driving torque control method for electric vehicle with in‐wheel motors
Authors: Yoshimura Masataka , Fujimoto Hiroshi 
Published: July 2012

AbstractAntislip control or slip ratio control can help improve the stability of EVs on a low‐μ road. However, these control methods cannot control the driving torque. In this paper we propose a driving torque control method for EVs with in‐wheel motors. By using this method we can control the driving torque directly. Simulations and experiments are carried out to demonstrate the effectiveness of the proposed method. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(3): 49‐58, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21286