bluuebunny/crossref_metadata_2025_split huggingface dataset:
Far Infrared Reflection Spectra of Sillenite Crystals and Their Solid Solutions
Authors: Senulienè D. , Babonas G. 
Published: July 2007

AbstractThe infrared reflection spectra of sillenite type crystals of Bi12MO20 (M :Si, Ge, Ti, Fe) are measured in the whole range of the first‐order phonon frequencies and analyzed using the Kramers‐Kronig relations. Two‐mode behavior is determined for several characteristic modes of Bi12Si1−xTixO20 and Bi12Ge1−xTixO20 solid solutions. The experimental data are discussed in the model of vibrating structural units. The vibration frequencies and the force constants for tetrahedra MO4 are calculated. The calculation results are in good agreement with experimental data for the modes with two‐mode behavior.
Crystal Structure and Phase Transitions in the A3B2X9 Family of Crystals
Authors: Tomaszewski P. E. 
Published: July 2007

AbstractA schematic representation of several kinds of crystal structure motives in A3B2X9 compounds is presented. The search for regularities in the occurrence of each motive with respect to the chemical composition of about 200 phases is described. The phase transitions observed in several crystals from this family are also discussed. The presented data on possible symmetry changes could be used for further studies of phase transitions.
A Simple Analysis of the Magnetic Susceptibilities in Quantum Dots of Optoelectronic Materials in the Presence of a Parallel Magnetic Field
Authors: Ghatak K. P. , Bhattacharyya D. 
Published: July 2007

AbstractAn attempt is made to study the dia‐ and paramagnetic susceptibilities of electrons in quantum dots of optoelectronic materials in the presence of a parallel magnetic field, on the basis of a newly formulated electron dispersion law. It is found, taking n‐Hg1−xCdxTe and In1−xGaxAsyP1−y lattice‐matched InP as examples that both susceptibilities increase with increasing electron concentration in oscillatory manners and increase monotonically with decreasing film thickness in the electric quantum limit. In addition, the numerical values of the susceptibilities in quaternary materials are greater than in the ternary compounds.
The Surface Barrier of a Uniaxial Anisotropic Superconductor
Authors: Saif A. G. 
Published: July 2007

AbstractThe role of a transport current on the annihilation of the surface barrier for a high‐temperature type‐II superconducting infinite slab of arbitrary thickness as well as for a high‐temperature type‐II superconducting cylinder are investigated. The London penetrating field, the vortex fields, and the Gibbs potential are calculated. The barrier depends on the external field strength, the value of the transport current flowing through the sample, and the orientation of the external field. Agreement with previous results in some cases is found.
Silver Ion Conducting Borate Glass. Evidence of Ion Association from Temperature Dependent Mobility, Conductivity, and IR Spectral Studies
Authors: Shaju K. M. , Chandra S. 
Published: July 2007

AbstractThe temperature dependence of ionic mobility for a silver ion conducting borate glass with composition 55.5 AgI22.25 Ag2O22.25 B2O3 (in mol%) is reported along with conductivity. Subsequently the value of mobile carriers n is calculated. The value of n is found to decrease with increase in temperature. Two types of ion association mechanisms viz., (i) self association and (ii) network association are proposed to explain the results. The proposed ion associations are checked by optical microscopy and temperature dependent IR spectral studies.
Thermal Expansion of Isotopically Substituted Alkali Hydrides
Authors: Tyutyunnik V. I. 
Published: July 2007

AbstractThe effect of both temperature and isotope substitution on the distance between ions in alkali hydride crystals is investigated by means of the rigid‐ion model with only nearest‐neighbour interactions. It is shown that the thermal expansion may be described as a function of the Coulomb potential parameters and the cation‐anion reduced mass. For the first time, the thermal expansion data are calculated for Na, K, Rb, and Cs hydrides and deuterides. The calculation results are in agreement with experimental values.
Strain‐Induced Interaction of Substitutional Atoms in Cubic Metals
Authors: Blanter M. S. 
Published: July 2007

AbstractThe energies of strain‐induced (elastic) interaction of pairs of substitutional atoms and host atom displacements around a substitutional atom are calculated for Al, Ag, Au, Cu, Ni, Pd, Cr, αFe, Mo, Nb, Ta, V, and W taking into account the discrete atomic structure of the host lattice. The elastic constants, Born‐von Karman constants of the host lattice, and coefficients of the concentration expansion of the solid solution lattice due to substitutional atoms are the numerical parameters used. A computer calculation is carried out in the general form appropriate for any substitutional atoms in these metals. The energies of strain‐induced interaction of substitutional atoms are of the same order as the “chemical” interaction energy and should be taken into account during computer simulation of structure and properties of the substitutional solid solutions.
Optical Properties of Wide‐Gap II‐VI ZnTe Epilayers
Authors: Averous M. , Abounadi A. , Aulombard R. L. , Bouchara D. , Briot N. , Briot O. , Calas J. , Cloitre T. , Gil B. 
Published: July 2007

AbstractThe optical properties of ZnTe epilayers grown by low‐pressure metal organic vapour phase epitaxy on GaAs and GaSb substrates are studied. The layers are grown by using the halide‐free triethylamine dimethylzinc adduct and di‐isopropyl telluride as zinc and tellurium precursors, respectively. A detailed analysis of the residual strain is offered as a function of layer thickness and substrate nature via reflectivity measurements performed at pumped liquid helium temperature. This is completed by an extensive analysis of near‐band‐edge photoluminescence spectra in order to discriminate the contribution of residual impurities. Using these precursors ZnTe layers with extremely low contamination rates are obtained.
Impurity States and Optical Transitions in Uniaxially Deformed Narrow‐Gap Semiconductors
Authors: Strikha M. V. , Vasko F. T. 
Published: July 2007

AbstractThe effect of uniaxial deformation along cubic axis on the states of point defects in narrow‐gap semiconductors is studied. The energy dependence of the splitting of deep h‐states into two doubly degenerate h1 and h2 states on the deformation value and the semiconductor characteristics is calculated. Changes of optical transitions from deep 1‐c and h‐centres with deformation are also examined. It is shown, that the absorption coefficient in this case is essentially anisotropic and its spectral dependences essentially differ from those in the case without deformation.
Hyperfine Effects in X‐Ray Emission Spectra of Transition Elements in Antiferromagnets
Authors: Barinskii R. L. , Kulikova I. M. 
Published: July 2007

AbstractAccording to experimental investigations of the width and energy shift of X‐ray Kα1, Lα1 lines Ti, V, Nb in antiferromagnetic compounds of transition (Fe, Mn, Cr) and rare‐earth elements (Ln) it is shown that the spin density on diamagnetic ions, Ti, V, Nb is due to the superexchange interaction with paramagnetic ions in the second coordination sphere via oxygen atoms. The magnitude of the spin density is a function of the number and total spin of paramagnetic ions and of the J component (Sj) of total spin (S) in the rare‐earth series in compounds LnVO4 and Ln(Ti, Nb)2O6. It is shown that the spin density on the rare‐earth ions is greatly influenced by the decrease in radial extension of the 4f shell for Ce to Sm.
Acoustohelicon Amplification in a Piezoelectric Semiconducting Plasma
Authors: Misra K. D. , Pandey M. K. 
Published: July 2007

AbstractAcoustohelicon amplification in semiconducting plasmas having piezoelectric or deformation potential coupling or both (viz., n‐InSb) are investigated using the kinetic approach. The dispersion relation for phonon‐ helicon interaction is derived in slow wave approximation. In case of a convective instability the amplification occurs if the drift velocity exceeds the velocity of sound (i.e. if the electric field is greater than 102 Vm−1) while in case of an absolute instability amplification is observed if the drift velocity is smaller than the velocity of sound (electric field less than 102 Vm−1). At higher electric fields (>4.27 × 104 Vm−1) the amplification coefficient for acoustohelicon waves, obtained by the kinetic approach, shows a maximum and then starts attenuating, contrary to the hydrodynamic approach where it is always monotonously increasing. The dependence of the amplification coefficient on various plasma parameters is studied in detail.
Monte‐Carlo Simulation on Random Magnetic Mixture with Competing Anisotropy. Oblique Antiferromagnetism of CsMn1−xCoxCl3 · 2 H2O
Authors: Kato T. 
Published: July 2007

AbstractA Monte‐Carlo simulation for a simplified model for CsMn1−xCoxCl3 · 2H2O which is a typical magnetic mixture with competing anisotropies is performed. From calculations for the magnetic moment of each atom and the magnetic susceptibilities, it is found that the characteristic features of the phase diagram are reproduced by the present model. That is, besides the CsMnCl3 · 2 H2O‐type antiferromagnetic phase and the CsCoCl3 · 2 H2O‐type one, an intermediate phase exists in between the two phases. In the intermediate concentration region two successive second‐order phase transitions occur with increasing temperature. The spin structure of the intermediate phase is consistent with the NMR result of Kubo et al., that is, there exist two perpendicular antiferromagnetic domains linked over the whole crystal, which are separated by domain walls.
Ion Beam Induced Luminescence of Alkali Halide Crystals
Authors: Suchańska M. , Bazhin A. I. , Konopelko E. I. 
Published: July 2007

AbstractNew experimental results bearing on luminescence induced by ion beam on pure and doped alkali halide crystals are reviewed. In the optical spectra besides activator luminescence bands new intrinsic luminescence bands are observed. The mechanism of the recombination of electrons from the conduction band with V2 hole centre is discussed.
Study of New Alkylammonium Hexachlorostannates and Their Phase Transitions by Differential Scanning Calorimetry and Infrared Spectroscopy
Authors: Čermák M. , Fuith A. , Vaněk P. , Silha J. , Málková Z. 
Published: July 2007

AbstractFourteen new structural phase transitions are detected in layer‐type monoalkylammonium hexachloro‐stannates (CnH2n+1NH3)2SnCl6 (n = 2 to 8) by means of differential scanning calorimetry. The basic thermodynamic data are determined for the transitions. The infrared spectra of the compounds are measured in the range of molecular vibrations (500 to 4000 cm−1) at room temperature and in dependence on temperature (77 to 298 K) by the method of nujol mull.
On the Mean Square Relative Atomic Displacements in Strongly Anharmonic Crystals
Authors: Zubov V. I. , Pascual M. F. , Rabelo J. N. Teixeira , de Faria A. C. 
Published: July 2007

AbstractThe correlative method of unsymmetrized self‐consistent field is used to study the mean square relative atomic displacements in crystals taking into account the strong anharmonicity and interatomic correlations. General expressions for these quantities in arbitrary crystal lattices are obtained. As an illustration, the mean square relative displacements between nearest, second, and third neighbours in a strongly anharmonic linear chain are calculated. The results are compared with those obtained with more rough approximations (harmonic, quasi‐harmonic, etc.). The influence of anharmonic effects is discussed.
Effect of Sb Additives on Electron Mobility in Amorphous Selenium
Authors: Mikla V. I. , Rubish V. M. 
Published: July 2007

AbstractTime‐of‐flight drift mobility experiments are carried out on amorphous SbxSe100−x to investigate the charge transport mechanism in these films. Electron drift mobility‐temperature data indicate that electron transport in a‐SbxSe100−x alloys is controlled by a set of shallow traps at 0.33 eV below the conduction band edge. Although the trap depth remains unchanged with increasing Sb content, the effective drift mobilities of electrons decrease with the Sb content in SbxSe100−x amorphous films.
Far‐Infrared ATR from Surface Exciton Polaritons
Authors: Albuquerque E. L. , Fulco P. 
Published: July 2007

AbstractThe surface exciton polariton spectrum in superlattices made up of two alternating media A and B is reported, where one of the layers shows spatial dispersion in its frequency dependent dielectric function. A theoretical approach based on the effective medium theory to determine the surface exciton polariton dispersion relation is used. Also the attenuated total reflectivity (ATR) is calculated to probe the surface exciton polariton modes.
Magnetoresistance and Hall Effect of Some Magnetically Ordered CrxMn1−xSb Single Crystals
Authors: Kohnke H. J. , Dunkel H. , Schünemann J.‐W. , Bärner K. , Buzhinsky S. 
Published: July 2007

AbstractThe anomalous Hall effect ϱH and the magnetoresistance Δϱ/ϱ of CrxMn1−xSb single crystals with x = 0.4 are measured for 4.2 K < T < 300 K, 0 < H < 7T. The Hall effect appears to be determined by anisotropic (magnon) spin scattering while the (complex) magnetoresistance appears to be also spin‐dependent but is described using at least two different spin scattering contributions.
Infrared Properties of Metallic and Insulating La1−zXzCu1−xMnxO3−δ Compounds (X = Sr, Ba)
Authors: Tang Yi , Shaltout I. , Braunstein R. , Helmolt R. V. , Haupt L. , Bärner K. 
Published: July 2007

AbstractThe mixed crystal series La1−zXzCu1−xMnxO3‐δ with X = Sr, Ba include high‐Tc superconductors, ferromagnetic (double exchange coupled) metals as well as spin‐glass‐like semiconductors, and therefore are selected for comparative studies of their infrared spectra. Optical conductivity is obtained between 150 and 4000cm−1 through Kramers‐Kronig analysis of infrared and optical reflectivity data. The information on energy dependent interactions between electrons and other quasiparticles or elementary excitations are provided through the analysis involving extended Drude and polaron transport models. Distinctive frequency dependent electron‐phonon coupling is found in all cases which manifests itself through the appearance of different current carrying quasi‐particles. Also, two or three prominent optical phonons are observed which are not completely screened even in the normal state of the high‐Tc superconductors and do not change their positions appreciably within each series. Line narrowing is suggested to occur when the magnetic long‐range order is switched on.
X‐ray study of diffuse scattering in Ni–20 at% Cr
Authors: Schönfeld B. , Ice G. E. , Sparks C. J. , Haubold H.‐G. , Schweika W. , Shaffer L. B. 
Published: July 2007

AbstractA single crystal of Ni–20 at% Cr aged at 744 K for 480 h, similar to the case of a previous neutron scattering experiment, is investigated by diffuse X‐ray scattering using X‐rays at three different wavelengths, λ = 0.2075 nm (5975 eV), 0.1489 nm (8327.2 eV), and 0.1531 nm (8097 eV). The short‐range order and displacement scattering are separated based on the 3λ method recently introduced as well as on the Georgopoulos‐Cohen method. Both evaluation schemes yield similar Warren‐Cowley short‐range order parameters with less agreement in the individual static atomic displacements. The nearest‐neighbor displacement obtained by the 3A method for NiCr pairs, is consistent with a simple phenomenological model in which the Cr atoms expand the Ni lattice in a short‐range ordered alloy. Effective pair interactions calculated from model crystals using the inverse Monte Carlo method are found to be larger than previously deduced from neutron scattering experiments. If these pair interactions are used in Monte Carlo simulations to calculate the transition temperatureT0of Ni2Cr,T0is underestimated compared with direct experimental findings.
A model‐free approach to eliminate autocorrelation when testing for process capability
Authors: Vännman Kerstin , Kulahci Murat 
Published: July 2007

AbstractThere is an increasing use of on‐line data acquisition systems in industry. This usually leads to autocorrelated data and implies that the assumption of independent observations has to be re‐examined. Most decision procedures for capability analysis assume independent data. In this article we present a new way of performing capability analysis when data are autocorrelated. This method is based on what can be called the ‘iterative skipping’ strategy. In that, by skipping a pre‐determined number of observations, e.g. considering every fifth observation, the data set is divided into subsamples for which the independence assumption may be valid. For each such subsample of the data we estimate a capability index. Then traditional tests, assuming independence, can be performed based on each estimated
capability index from the subsamples. By combining the information from each test statistic based on the subsamples in a suitable way, a new and efficient decision procedure is obtained. We discuss different ways of combining the information from these individual tests. A main appeal of our proposed method is that no time‐series model is needed. Copyright © 2007 John Wiley & Sons, Ltd.
Quantitative Structure–Retention Relationship Study of a Variety of Compounds in Reversed‐Phase Liquid Chromatography: A PLS‐MLR‐STANN Approach
Authors: Jalali‐Heravi M. , Garkani‐Nejad Z. , Kyani A. 
Published: July 2007

AbstractA quantitative structure–retention relationships model has been developed to study the retention behavior of 87 aliphatic and aromatic compounds in Reversed‐Phase Liquid Chromatography (RPLC) on five bonded‐phase columns differing in silanol group acidity. Six numerical descriptors of Molecular Mass (M), partial charge of the most negative atom (NPCH), partial charge of the most positive hydrogen (PCHH), van der Waals volume (VOLUME), Dipole Moment (DIMO), and Highest Occupied Molecular Orbital (HOMO) have been calculated for each compound. A separate Multiple Linear Regression (MLR) model has been developed using the six descriptors for each column. Partial Least Square (PLS) combined with MLR mean effects has been used for the mechanism interpretation. The descriptors of M, HOMO, and DIMO showed the largest PLS regression coefficients. It is found in the present work that solute size, n–π donor–acceptor and dipole–dipole interactions play a major role in the RPLC retention mechanism. Also, a self‐training artificial neural network was developed using the six descriptors as its inputs. The results obtained using this model are in good agreement with the experimental results of all five columns. Superiority of this model with low standard errors and high correlation coefficients for all five stationary phases reveals nonlinear characteristics of retention in RPLC. Successful application of the six descriptors in modeling of the retention behavior of different data sets using gas chromatography (previous work) and RPLC (present work) with different stationary phases reveals the robustness of the parameters.
QSAR Studies and Molecular Design of Phenanthrene‐based Tylophorine Derivatives with Anticancer Activity
Authors: Liao Si‐Yan , Chen Jin‐Can , Qian Li , Shen Yong , Zheng Kang‐Cheng 
Published: July 2007

AbstractThe Quantitative Structure–Activity Relationship (QSAR) of a series of novel phenanthrene‐based tylophorine derivatives with anticancer activity has been studied by using the Density Functional Theory (DFT), Molecular Mechanics (MM2), and statistical methods. The established model shows not only significant statistical quality, but also predictive ability, with the square of adjusted correlation coefficient (R2A=0.813) and the square of the cross‐validation coefficient (q2=0.748). We find that the anticancer activity expressed as pIC50, which is defined as the negative value of the logarithm of necessary molar concentration of this series of compounds to cause 50% growth inhibition against the human A549 lung cancer cell line, closely relates with the energy (EHOMO) of the Highest Occupied Molecular Orbital (HOMO), the net charge of the terminal H atom of substituent R2 ($\rm{ Q_{{\rm{HR}}_{\rm{2}} } }$), the hydrophobic coefficient of substituent R2 (log $\rm{ P_{{\rm{R}}_{\rm{2}} } }$), and the net charges of the first atom of substituent R1 ($\rm{ Q_{{\rm{FR}}_{\rm{1}} } }$). The same model was further applied to predict the pIC50 for six recently reported congeneric compounds as external test set, and the predicted pIC50 values are close to the experimental ones, and thus it further confirms that this QSAR model has high predictive ability. The theoretical results can offer some useful references for understanding the action mechanism and designing new compounds with anticancer activity. Based on this QSAR equation, ten new compounds with higher anticancer activity have been theoretically designed and are expecting the experimental confirmation.
Eleven theses of general systems theory (GST)
Authors: Waelchli Fred 
Published: July 2007

AbstractThis paper chronicles an effort to distill and order (for purposes of discussion and elaboration) frequently mentioned and significant ideas encountered in the literature of General Systems theory (GST). The product is a set of eleven theses, representing the author's selection and collation of seminal and recurrent GST themes. The author argues that attention to theory could aid the effort to develop practical applications of systems thinking. (Remember that a thesis is a statement or assertion, offered originally without proof, as the basis for an argument, discussion, or empirical test.)
“General systems theory, cultural change, and a human science foundation for planning and design”
Authors: Motloch John L. , Woodfin Thomas 
Published: July 2007

AbstractAbstract — This paper integrates the knowledge‐base concerning systems, their behavior and structure, and the management of complex systems ‐ to provide insight to physical planning and design in equilibrium and rapidly‐changing conditions. It contributes to the redefinition of the professions of physical planning and design; and the establishment of their human science foundations.
Gordon pask — a skeleton for an unofficial biography
Authors: Glanville Ranulph 
Published: July 2007

AbstractGordon Pask was born on June 28th, 1928, the son of Percy (who imported and exported fruits) and his wife Mary. He had two elder brothers, Alfred (a Methodist minister) and Edgar (who was a professor of anaesthesia whose studies of hypothermia in pilots surviving “prangs” in World War II contributed enormously, not just then, but since to the survival of burns patients and those who survive air crashes). He was educated at Rydal School in North Wales, and then obtained Diplomas in Geology and Mining Engineering from Bangor and Liverpool Technical Colleges. In 1952 he gained his BA from Downing College, Cambridge, with his MA following in 1954. He has a Ph D from University College, University of London (in psychology), and was awarded the first D Sc, in Cybernetics, by the Open University, in 1974.He married Elizabeth Poole, in 1956, and they have two daughters: Amanda, born 1961, and Hermione, born 1967.Elizabeth and Gordon Pask live in Clapham's Old Town, an ancient village in south west London.
For Gordon, with love
Authors: Beer Stafford 
Published: July 2007

AbstractAbstract — This record was made some years ago, so that the quarter‐century referred to has become exactly forty years. Thus we are now dealing either with improper fractions or with expanded centuries of a hundred and twenty‐eight years; but in either case we are concerned with a second‐order regulator compensating for the intrusion of a regulator that was compensating for its own intrusion in the first place (which was not, you observe, here).