bluuebunny/crossref_metadata_2025_split huggingface dataset:
A computational protocol to probe the role of solvation effects on the reduction potential of azurin mutants
Authors: Barone Vincenzo , De Rienzo Francesca , Langella Emma , Menziani M. Cristina , Rega Nadia , Sola Marco 
Published: November 2005

AbstractSemiquantitative relationships between thermodynamic parameters of Cu2+ reduction experimentally measured for a series of azurin mutants and the solvation free energy of the oxidized state of the proteins were derived. Solvation free energy calculations were carried out within an ONIOM/PCM scheme specifically adapted to this protein series. The method proved to be able to capture the main determinants of the measured reduction parameters, providing satisfactory predictions of the E°′. Proteins 2006. © 2005 Wiley‐Liss, Inc.
Incident investigation: Process to identify root causes of mechanical failures
Authors: Dowell A. M. (Art) 
Published: November 2005

AbstractThis paper describes an actual incident investigation into unexpected premature failure of sealed diaphragm pressure transmitters in a chemical process. Some nontypical investigation tools from the CCPS Guidelines for Investigating Chemical Process Incidents (2nd edition) were used.A typical failure allowed a release of a corrosive process fluid with potential injury to personnel. The failures also required a shutdown of the process with loss of production. The cause of the problem was elusive; pressure transmitters from the same manufacturer had no problems in a similar process unit, although component designs differed between the two units.The investigation included confirmation of materials of construction, photographic and visual analyses of failed components, simulation of assembly of the pressure transmitter in the process and measurement of torque values, and brainstorming of possible failure mechanisms. Several hypotheses were tested using a fact–hypothesis matrix to determine most likely cause scenarios. Similarly, a matrix was used to illustrate which scenarios could be prevented by which corrective actions. The investigation included a root cause analysis tree to confirm cause scenarios.The paper discusses the incident investigation process, including diversity of skills on the investigation team, and how each of the tools was used. The paper also discusses the communication of the findings to operations. © 2005 American Institute of Chemical Engineers Process Saf Prog, 2006
Optical properties of Ge nanowires grown on Si(100) and (111) substrates: Nanowire–substrate heterointerfaces
Authors: Kamenev B. V. , Sharma V. , Tsybeskov L. , Kamins T. I. 
Published: November 2005

AbstractWe report photoluminescence (PL) and Raman scattering (RS) measurements of (111) oriented Ge nanowires (NWs) grown by chemical vapor deposition on (100) and (111) silicon substrates. Our PL measurements strongly suggest that the observed emission originates at low‐defect density Ge NW – Si substrate interfaces. Both, PL and RS data indicate that Si–Ge intermixing and strain are more pronounced for the Ge NW – (111) Si interface, while NWs grown on (100) Si substrates are relaxed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The influence of Sn4+ and/or Mo6+ ions on the structure, electrical and gas sensing properties of Mg‐ferrite
Authors: Rezlescu N. , Doroftei C. , Rezlescu E. , Popa P. D. 
Published: November 2005

AbstractThe influence of partial replacing of Mg and Fe ions by Sn and Mo ions, respectively, on the structural and conductivity properties of MgFe2O4 ferrite is studied by means XRD, SEM and resistivity measurements. Four compositions of ferrites, Mg1–xSnxMoyFe2–yO4 (x = 0, 0.1 and y = 0, 0.02) were prepared by autocombustion, starting from metal nitrates. The presence of foreign phase was evidenced in the Sn containing ferrite. Also, Sn and Mo ions induced structural changes regarding grain size and porosity. The finest granulation, of about 100 nm, was observed in the Sn containing sample, Mg0.9Sn0.1Fe2O4 having the highest porosity. The electrical resistivity increased with about two orders in magnitude when Sn4+ ions partially substituted Mg in MgFe2O4 ferrite. All samples were tested for sensing properties to reducing gases: ethanol and acetone. The gas sensitivity considerably depends on the kind of substituent ion and the type of gas to be detected. All the ferrites were more sensitive to acetone than to ethanol. It was revealed that among all ferrites tested, Mg0.9Sn0.1Fe2O4 is the most sensitive to acetone. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of a new transparent‐conducting material of ZnO doped ITO thin films
Authors: Ali H. M. 
Published: November 2005

AbstractThin films of indium tin oxide (ITO) doped with zinc oxide have the remarkable properties of being conductive yet still highly transparent in the visible and near‐IR spectral ranges. The Electron beam deposi‐ tion technique is one of the simplest and least expensive ways of preparing. High‐quality ITO thin films have been deposited on glass substrates by Electron beam evaporation technique. The effect of doping and substrate deposition temperature was found to have a significant effect on the structure, electrical and optical properties of ZnO doped ITO films. The average optical transmittance has been increased with in‐ creasing the substrate temperature. The maximum value of transmittance is greater than 84% in the visible region and 85% in the NIR region obtained for film with Zn/ITO = 0.13 at substrate temperature 200 °C. The dielectric constant, average excitation energy for electronic transitions (E o), the dispersion energy (E d), the long wavelength refractive index (n ∞), average oscillator wave length (λ o) and oscillator strength S o for the thin films were determined and presented in this work. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Interstitial to antisite defect conversion during the molecular beam epitaxial deposition on c(4 3 4) GaAs(001) surfaces
Authors: Kunsági‐Máté S. , Schür C. , Marek T. 
Published: November 2005

AbstractIn the model describing the origin of excess arsenic content in low‐temperature grown GaAs layers developed by the research group of professor Strunk during the last ten years, formation of an interstitial As atom was identified as precursor to excess arsenic formation. After an As2 molecule interacts with the GaAs surface, a metastable conformation can form, where one of the As atoms of the As2 molecule is located in an interstitial position. Starting from this geometry, during growth stable conformations can easily arise by the assistance of one or two arriving Ga atoms which stabilize the interstitial As atom in its position by forming a half or full cage‐like structure. Another model describes how the antisite excess As atoms form in GaAs layers by an incomplete exchange of As atoms in the surface reconstruction layer with arriving Ga atoms. The present article connects these two aspects of the excess As formation by analyzing the stability of the interstitial excess As atom, calculated in four different atomic arrangements according to experimentally observed surface structures. Energies of initial, final and transition states of interstitial to antisite reaction path were calculated by DFT/B3LYP/6‐31++G method. Results show that interstitial to antisite conversion happens preferably after a half‐cage formation, while after a full cage has been formed, the interstitial As atom remains fixed in its position. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Radiation‐induced effects in GaN by photoconductivity analysis
Authors: Castaldini A. , Cavallini A. , Polenta L. 
Published: November 2005

AbstractSpectral photoconductivity is a very efficient tool to explore the forbidden gap of wide gap semiconductors, detecting band‐to‐band or deep level‐to‐band transitions of the charge carriers.In this paper we present some results obtained by spectral photoconductivity concerning HVPE (hydride vapour phase epitaxy) grown gallium nitride submitted to high energy proton irradiation. The behaviour of the material before and after irradiation may give information on the characteristics of the deep bands and their association to surface or bulk defects. In particular we observed how irradiation quenches the yellow band and correspondingly inhibits persistent photocurrent effects. Persistent photocurrent measurements carried out at different temperatures give further insights on the radiation‐induced effects.The possible correlation among the deep‐related transitions and the persistent photo‐effects is here proposed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Statistical analysis of vanadium in gallium arsenide
Authors: Rebey A. , Bchetnia A. , Jani B. El 
Published: November 2005

AbstractThe electrical properties of vanadium‐doped GaAs grown by metalorganic vapor phase epitaxy were studied between 77 and 300 K. The temperature‐dependent electron concentration, for different partial pressures of VCl4, was simulated using the charge balance equation. A calculation model was used with parameters (energy levels and V concentration) derived from photoluminescence, deep‐level transient spectroscopy and secondary ion mass spectroscopy measurements. The magnitude and the temperature dependence of neutral and ionized V concentrations were determined. It is shown that most of the V concentration is inactive. This is in good agreement with some previous reports in the literature. The detailed analysis including the probability of V donor incorporation in GaAs was then extended to explain the evolution of electron concentration as a function of partial pressure of VCl4. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mixed mode electrical transport behavior in nanocrystalline La–Ca‐Manganite synthesized by microwave refluxing
Authors: Nayak Bibhuti B. , Vitta Satish , Bahadur D. 
Published: November 2005

AbstractNanocrystalline La0.67Ca0.33MnO3 powders were prepared from organic precursors using a microwave synthesis technique. A variation of the precursor solution pH and annealing temperature was found to change the effective Mn4+ concentration which leads to variations in electronic behavior. In all the cases however, a single phase microstructure was observed showing the stability of orthorhombic manganite. The nanocrystalline manganite prepared from a solution with a pH of 10.5 has the lowest Mn4+ and accordingly low electrical and magnetic transition temperatures. The electrical transport behavior of powders prepared from precursor solutions with pH of 11.5 and 12.5 could be modeled using an effective medium approach across the whole temperature range, 30 K to 300 K. The magnetoresistance in these nanocrystalline manganites increases with decreasing temperature, an effect of increased grain boundaries. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of InN related to surface plasmons
Authors: Shubina T. V. , Leymarie J. , Jmerik V. N. , Toropov A. A. , Vasson A. , Amano H. , Schaff W. J. , Monemar B. , Ivanov S. V. 
Published: November 2005

AbstractWe report on the complex nature of infrared luminescence and absorption in InN films, which cannot be entirely explained by the concept of a conventional narrow‐gap semiconductor. In particular, it concerns the detection of peaks near absorption edges by both thermally detected optical absorption and photoluminescence excitation spectroscopy and the observation of extraordinarily strong resonant enhancement of emission. To describe the experimental data a model is proposed, which takes into account surface plasmons in metal‐like inclusions, modifying the optical properties of InN. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron–hole complexes in individual semimagnetic quantum dots
Authors: Dorozhkin P. S. , Brichkin A. S. , Kulakovskii V. D. , Chernenko A. V. , Zaitsev S. V. , Ivanov S. V. , Toropov A. A. 
Published: November 2005

AbstractWe compare magneto‐photoluminescence spectra of individual semimagnetic quantum dots (QDs) with different strengths of exchange interaction between a localized exciton and surrounding magnetic ions. The spectra of individual QDs with strong magnetic exchange interaction show a single line corresponding to a ground‐state exciton. In QDs with weak interaction, exciton and biexciton spectra are identified, both showing a fine structure due to electron–hole exchange interaction. The anticrossing of dark and bright exciton states in low‐symmetry QDs is demonstrated in magnetic fields in the Faraday geometry. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photon losses in porous silicon microcavities
Authors: Rubo Yuri G. , Solano M. Toledo , del Río J. A. 
Published: November 2005

AbstractWe study theoretically the optical losses in a microcavity made of porous silicon. A quantum derivation of the shape of the resonant transmittance peak for the general case is presented and then we analyze the effect of Rayleigh scattering of light on the disordered structure of porous silicon in details. We introduce a simple model of porous silicon disorder, which allows to estimate the total rate of the Rayleigh scattering from the fundamental microcavity mode. We also investigate the angular distribution of scattered photons. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Roles for aluminium indium nitride insertion layers in fabrication of GaN‐based microcavities
Authors: Bejtka K. , Rizzi F. , Edwards P. R. , Martin R. W. , Gu E. , Dawson M. D. , Watson I. M. , Sellers I. R. , Semond F. 
Published: November 2005

AbstractAlInN alloys achieve an in‐plane lattice match to hexagonal GaN at an indium nitride mole fraction of ∼18%. Meanwhile Al0.82In0.18N displays a refractive index contrast of ∼7% with GaN at visible wavelengths. We illustrate the use of Al0.82In0.18N insertion layers to control layer thicknesses during homoepitaxial growth of GaN‐based microcavities, using in situ optical reflectometry. The structures discussed are 3λ /2 microcavities incorporating distributed InGaN quantum wells tailored for emission at ∼400 nm. As‐grown samples have been characterised by techniques including cathodoluminescence spectroscopy. In addition to their role in growth monitoring, there are several post‐growth processing steps in which Al0.82In0.18N insertion layers can assist microcavity fabrication. We focus here on a demonstration of the ∼1:5 etch rate selectivity obtainable between Al0.82In0.18N and GaN in reactive ion etching. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Resonant acousto‐optic response of microcavity polaritons
Authors: Ivanov A. L. 
Published: November 2005

AbstractWe review the optical properties of microcavity polaritons parametrically driven by a surface acoustic wave (SAW). In this case the acoustically‐induced quasi‐energy (Brillouin) spectrum of microcavity polaritons is well‐developed even for modest acoustic intensities. As a result, in sharp contrast with conventional acousto‐optics, the resonantly enhanced Bragg spectra reveal a robust structure with multiple orders of diffracted light, i.e. a Brillouin band structure of SAW‐driven polaritons can be directly visualized. In particular, for a GaAs‐based microcavity pumped by the SAW of ν saw = 1 GHz and I ac ≃ 100 W/cm2, the main acoustically‐induced band gap in the polariton spectrum can be as large as Δ acMC ≃ 0.6 meV, and the Bragg replicas up to n = 3 can be observed. Finally, we discuss the resonant acousto‐optic effect in (GaAs) microcavities for device applications. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Conductance of Aharonov–Bohm interferometers embedded with an interacting dot: slave‐boson mean‐field calculation
Authors: Takagaki Y. , Ploog K. H. 
Published: November 2005

AbstractWe numerically calculate the conductance of a one‐dimensional Aharonov–Bohm loop containing a weakly coupled dot. The Coulomb repulsion is taken into account in the dot within the slave‐boson mean‐field approximation. We avoid the so‐called phase locking by attaching an additional lead to the loop. The phase of the electron wavefunction deduced from the Aharonov–Bohm oscillation changes gradually by π when the Fermi energy sweeps across a transmission resonance in the dot. The asymmetric lineshape of Fano‐type resonances is also examined. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Impurity levels in the layered semiconductor p‐GaSe doped with group V elements As, Bi and Sb
Authors: Shigetomi S. , Ikari T. 
Published: November 2005

AbstractThe radiative and non radiative recombination mechanisms in the As, Sb and Bi‐doped GaSe have been investigated on the basis of photoluminescence (PL) and Hall effect measurements. The PL features (at 77 K) related to the impurity levels coming from the As, Sb and Bi atoms are dominated by a broad emission band at about 1.7 eV. From the temperature dependences of the peak energy and PL intensity and the dependence of excitation intensity of peak energy, it was found that the 1.7 eV emission band is due to the transition from the shallow donor level at about 0.08 eV below the conduction band to the deep acceptor. In addition it was found, from the temperature dependence of hole concentration, that a deep acceptor level at about 0.6 eV above the valence band is formed by the doping atoms. It is associated with defects or defect complexes. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Incorporation of nitrogen acceptors in ZnO powder
Authors: Pfisterer D. , Sann J. , Hofmann D. M. , Plana M. , Neumann A. , Lerch M. , Meyer B. K. 
Published: November 2005

AbstractWe report on the preparation and characterization of N‐doped ZnO powders. EPR measurements revealed the presence of N‐acceptors similar to those found in single crystals (Aiso = 1.225 mT, Aaniso = 0.864 mT, g‖ = 1.9953, g⊥ = 1.9633). The photoluminescence of the samples shows donor to shallow acceptor recombinations. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bound states of helium atom in dense plasmas
Authors: Kar Sabyasachi , Ho Y. K. 
Published: November 2005

AbstractWe have obtained the bound 1s2 1S, 1s2s 1,3S, and 1s2p 1,3P states energies of helium atom in dense plasma environments in accurate variation calculations. A screened Coulomb potential to represent the Debye model is used for the interaction between the charged particles. A correlated wave function consisting of a generalized exponential expansion has been used to take care of the correlation effect. The 1s2 1S, 1s2s 1,3S, and 1s2p 1,3P states energies along with the ionization potential, the energy splitting between the 1s2s 3S, and 1s2s 1S states, transition energies between the ground state and low‐excited states of He estimated for various Debye lengths, are reported. The results show high degree of accuracy even under strong plasma conditions. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Analyzing the contribution of individual resonance poles of the S‐matrix to two‐channel scattering
Authors: Rakityansky S. A. , Elander N. 
Published: November 2005

AbstractA two‐channel problem is considered within a method based on first‐order differential equations that are equivalent to the corresponding Schrödinger equation but more convenient for dealing with resonant phenomena. Using these equations, it is possible to calculate directly the Jost matrix for practically any complex value of the energy. The spectral points (bound and resonant states) can therefore be located in a rigorous way, namely, as zeros of the Jost matrix determinant. When calculating the Jost matrix, the differential equations are solved and thus, at the same time, the wave function is obtained with the correct asymptotic behavior analytically embedded in the solution. The method offers a very accurate way of calculating not only total widths of resonances but their partial widths as well. For each pole of the S‐matrix, its residue can be calculated rather accurately, which makes it possible to obtain the Mittag–Leffler‐type expansion of the S‐matrix as a sum of the singular terms (representing the resonances) and the background term (contour integral). As an example, the two‐channel model by Noro and Taylor is considered. It is demonstrated how the contributions of individual resonance poles to the scattering cross section can be analyzed using the Mittag–Leffler expansion and the Argand plot technique. This example shows that even poles situated far away from the physical real axis may make significant contributions to the cross section. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Nonperturbative solutions for one‐dimensional Schrödinger equation with position‐dependent mass
Authors: Solimannejad Mohammad , Moayedi Seyed Kamran , Tavakoli Majid 
Published: November 2005

AbstractIn this article, we discuss the relationship between exact solvability of the position‐dependent mass Schrödinger equation with analytical solutions of an ordinary Schrödinger equation in quantum mechanics. Furthermore, it is demonstrated that nonperturbative solutions of ordinary Schrödinger equation for a sextic potential leads to a large class of exact solutions for the position‐dependent mass Schrödinger equation. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Proton affinity of five‐membered heterocyclic amines: Assessment of computational procedures
Authors: Rao J. Srinivasa , Sastry G. Narahari 
Published: November 2005

AbstractAb initio quantum chemical calculations, G3B3, second‐order Møller–Plesset (MP2), and the hybrid density functional method B3LYP were employed to compute the proton affinities of 24 heterocyclic amines. A range of basis sets are employed, starting from double‐ζ polarization quality to triple‐ζ quality basis set with augmented diffuse and polarization function. Experimental values were used to calibrate the performance of various theoretical models. The regioselectivity for the protonation has been unambiguously established by performing B3LYP/6‐31G* calculations on the possible putative sites of attack. For the given series of compounds the performance of B3LYP/6‐31++G** and G3B3 levels of theory have been in excellent agreement with the experimental results with the deviations are of the order comparable with the experimental error. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Theoretical study of initiated reaction mechanism of polymerization of maleic anhydride catalyzed by OH−1 anion
Authors: Xiao Hua , Feng‐Li Bei , Xin Wang , Xu‐Jie Yang , Lu‐De Lu 
Published: November 2005

AbstractA theoretical study of the polymerization reaction mechanism of maleic anhydride (MA) initiated by hydrate is presented. The reaction pathway has been studied with the density functional theory (DFT) method at the B3LYP/6‐311G** level. The geometrical parameters of transition states (TS) are optimized; intrinsic reaction coordinate (IRC) calculations have also been performed to obtain further credible features. Frequency analyses of all the stationary points are calculated at the same basis sets. The total energies of all geometries are corrected at second‐order Møller–Plesset (MP2)/6‐311G**. Calculation results reveal that the reaction mechanism is attributable to anion polymerization. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006