bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dark exciton decay dynamics of a semiconductor quantum dot
Authors: Dalgarno Paul A. , Smith Jason M. , Gerardot Brian D. , Govorov Alexander O. , Karrai Khaled , Petroff Pierre M. , Warburton Richard J. 
Published: November 2005

AbstractWe report measurements of the exciton decay dynamics of a single self‐assembled quantum dot following non‐resonant excitation. The singly charged exciton, the trion, exhibits a simple one component exponential decay corresponding to radiative recombination. Conversely, the neutral exciton exhibits a two component exponential decay. We argue that the secondary component arises from dark exciton creation and subsequent conversion to a bright exciton through a spin flip. The spin flip time is a strong function of the bias applied between a Fermi reservoir close to the dot and a Schottky gate electrode as a result of a Kondo‐like spin swap process. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polarisation properties of optical parametric oscillator emission in a semiconductor microcavity
Authors: Krizhanovskii D. N. , Sanvitto D. , Ceccarelli S. , Skolnick M. S. , Roberts J. S. 
Published: November 2005

AbstractPolarisation properties of the light emitted by a semiconductor microcavity are studied in the regime of stimulated parametric scattering for one and two beam continuous wave excitation. For linearly polarized excitation with one beam we observe strongly linearly polarized signal emission with the plane of polarization rotated by 60°–120° relative to that of the pump. Moreover, a degree of circular polarisation is found for certain orientations of the plane of polarisation of the pump. These effects arise from the splitting between linearly and circularly polarized polariton states, as well as from the anisotropy of polariton‐polariton scattering. Resonantly exciting the lower polariton branch simultaneously with two independent cross circularly polarised pumps with opposite k‐vectors, we observe an enhancement of the total signal emission at k = 0 by 3–5 times, accompanied by a new idler state located at k = 0. The effect indicates efficient scattering of two pump polaritons, involving a biexciton intermediate state. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
First‐principles study of BNxSb1–x, BPxSb1–x and BAsxSb1–x alloys
Authors: El Haj Hassan F. 
Published: November 2005

AbstractThe first ab initio calculations were carried out for the electronic, structural and thermodynamic properties of BNxSb1–x, BPxSb1–x and BAsxSb1–x boron ternary alloys. The full potential linearized augmented plane wave (FP‐LAPW) method was employed within density functional theory (DFT). The local density approximation was used with generalized gradient correction (GGA) as well as the Engel–Vosko GGA formalism to calculate the band gap. The effect of composition on lattice constants, bulk modulus and band gap was investigated. Deviations of the lattice constants from Vegard's law and the bulk modulus from linear concentration dependence (LCD) were observed for the three alloys. The microscopic origins of the gap bowing were explained by using the approach of Zunger and co‐workers. In addition, the thermodynamic stability of these alloys was investigated by calculating the excess enthalpy of mixing ΔHm as well as the phase diagram. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dielectric and calorimetric studies of ferroelectric phase transitions in Li(2–x)NaxGe4O9 crystals
Authors: Cebula I. , Cach R. 
Published: November 2005

AbstractThe ferroelectric phase transitions of LiNaGe4O9, Li1.1Na0.9Ge4O9, Li1.2Na0.8Ge4O9 and Li1.7Na0.3Ge4O9 crystals were studied. Experiments were carried out by means of classical dielectric measurements and using an AC calorimetric specific‐heat measuring system. Critical behaviour is explained within Landau theory. The expansion coefficients of the state equation are determined. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of dielectric function inhomogeneities on spectral width of Er3+ ion luminescence in structures of Si nanocrystals
Authors: Teterukov S. A. , Lisachenko M. G. , Zhigunov D. M. , Shalygina O. A. , Kashkarov P. K. , Timoshenko V. Yu. 
Published: November 2005

AbstractCalculations of the Stark‐effect splitting of the energy levels of Er3+ ions in SiO2 layers alternating with layers of quasi‐ordered Si‐nanocrystals have been performed. The splitting is caused by the electric field of image charges at the interface between the layers having different dielectric constants. It has been established, that the splitting increases with increasing difference between the dielectric constants of SiO2 and nanocrystalline layers, and as the ions approach the interface. The results obtained allow us to explain the experimental data on an additional spectral broadening of the Er3+ photoluminescence line at 0.8 eV with increasing thickness of nanocrystalline Si layers. Moreover, a modeling of the spectral line shape has been performed, assuming that it consists of six components, properties of which depend on the additional electric field induced by dielectric function inhomogeneity. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thinking inside the box: Novel linear scaling algorithm for Coulomb potential evaluation
Authors: Thompson David C. , Ayers Paul W. 
Published: November 2005

AbstractBeginning with the Poisson equation, and expanding the electronic potential in terms of sine functions, the natural orbitals for describing the particle‐in‐a‐box problem, we find that simple analytic forms can be found for the evaluation of the Coulomb energy for both the interacting and non‐interacting system of N‐electrons in a box. This method is reminiscent of fast‐Fourier transform and scales linearly. To improve the usefulness of this result, we generalize the idea by considering a molecular system, embedded in a box, within which we determine the electrostatic potential, in the same manner as that described for our model systems. Within this general formalism, we consider both periodic and aperiodic recipes with specific application to systems described using Gaussian orbitals; although in principle the method is seen to be completely general. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Are the hydrogen bonds involving sulfur bases inverse or anomalous?
Authors: Vila Antonio , Mosquera Ricardo A. 
Published: November 2005

AbstractThe hydrogen‐bonded complexes (HBCs) of H2S, CH2S, and CH4S with H–F (hydrogen fluoride) were studied within the framework of the quantum theory of atoms in molecules at several theoretical levels (HF, B3LYP, MP2, and QCISD) with a wide range of basis sets. According to the integrated atomic populations obtained at correlated levels, the interacting hydrogen of the acid gains charge upon complexation, in sharp contrast to the conventional picture of hydrogen bonding, whereas the HF method yields a small loss of charge. The study of several HnA…HmD HBCs of hydrides, where A is the hydrogen‐acceptor atom and D is the atom bonded to the hydrogen donor, reveals this behavior is followed when the electronegativity of D significantly exceeds that of A. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Dispersion treatment for NDDO‐based semiempirical MO techniques
Authors: Martin Bodo , Clark Timothy 
Published: November 2005

AbstractWe introduce an additional term to treat dispersion in NDDO‐based semiempirical molecular orbital techniques. The dispersion energy is calculated using additive “atomic orbital” polarizability tensors determined with our modified version of Rivail's variational technique. Frequency‐dependent polarizabilities can be obtained using Padé approximants, which proved more reliable than the Unsöld approximation or a Taylor‐series approach. Dispersion energies are best calculated using the Slater–Kirkwood modification of the London formula, although they can also be obtained using the Casimir–Polder approach with frequency‐dependent polarizabilities. A test parameterization using MNDO as the semiempirical technique indicated that weak interactions can be reproduced satisfactorily. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Mass spectrometric investigation of Maltacines E1a and E1b—two members of the Maltacine family of peptide antibiotics
Authors: Hagelin Gunnar 
Published: November 2005

AbstractWe have recently described the discovery of the Maltacines—a new family of cyclic peptide antibiotics from Bacillus subtilis. In this paper the mass spectrometric characterisation of two of the members is reported. A chemoselective ring opening with base to give the linear peptides was necessary before mass spectrometric characterisation could be performed. MSn of the singly and doubly charged protonated molecules gave uninterrupted series of Bn and Y″n ions that allowed determination of the amino acid sequence. By using a combination of derivatisation with phenylisothiocyanate (PITC), high‐resolution mass spectrometry and H/D exchange, the identities of three unknown residues were determined. The nature and position of the cyclic structure were disclosed by a chemoselective ring opening with Na18OH and it was found to be a lactone formed between a hydroxyl of residue number 4 and the C‐terminal amino acid number 12. Peptides with different combinations of P/Q and P/K at the N‐terminus were synthesised to verify the sequence of the N‐terminal B2 ion. The structure of the two peptides is proposed to be: E1a: cyclo‐4,12(P‐Q‐Y‐Adip‐V‐E‐T‐Y‐Orn‐S‐Y‐I‐OH) and E1b: cyclo‐4,12(P‐Q‐Y‐Adip‐V‐E‐T‐Y‐K‐S‐Y‐I‐OH). Adip = (2‐amino‐4,5‐dihydroxypentanoic acid). Copyright © 2005 John Wiley & Sons, Ltd.
The probabilistic analysis of a greedy satisfiability algorithm
Authors: Kaporis Alexis C. , Kirousis Lefteris M. , Lalas Efthimios G. 
Published: November 2005

AbstractOn input a random 3‐CNF formula of clauses‐to‐variables ratior3applies repeatedly the following simple heuristic: Set to True a literal that appears in the maximum number of clauses, irrespective of their size and the number of occurrences of the negation of the literal (ties are broken randomly; 1‐clauses when they appear get priority). We prove that forr3< 3.42 this heuristic succeeds with probability asymptotically bounded away from zero. Previously, heuristics of increasing sophistication were shown to succeed forr3< 3.26. We improve up tor3< 3.52 by further exploiting the degree of the negation of the evaluated to True literal. © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2006
On random ±1 matrices: Singularity and determinant
Authors: Tao Terence , Vu Van 
Published: November 2005

AbstractThis papers contains two results concerning random n × n Bernoulli matrices. First, we show that with probability tending to 1 the determinant has absolute value
$\sqrt{n!}\exp(O(\sqrt{n \ln n}))$. Next, we prove a new upper bound 0.958n on the probability that the matrix is singular.© 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2006
The rediscovery of industrial dynamics: the contribution of system dynamics to supply chain management in a dynamic and fragmented world
Authors: Akkermans Henk , Dellaert Nico 
Published: November 2005

AbstractThe field of supply chain management (SCM) almost started with the publication of Forrester's Industrial Dynamics, but it seems that the relevance of this seminal publication for the field of system dynamics has never been so relevant for the field of SCM than today. In this introduction to the special issue of the System Dynamics Review on the Dynamics of Supply Chains and Networks, the authors make this statement on the basis of the articles that have found their way into this special issue, and on a brief review of SCM practice and theory for the past four decades. They explain why this recent and late rediscovery of industrial dynamics is understandable, and also point at sensible and likely areas of further cross‐fertilization of system dynamics and SCM. Copyright © 2005 John Wiley & Sons, Ltd.
Accounting for the size of molecules in determination of adsorption isotherms by XPS; exemplified by adsorption of chicken egg albumin on titanium
Authors: Aeimbhu Areeya , Castle James E. , Singjai Pisith 
Published: November 2005

AbstractThe adsorption of chicken egg albumin on commercially pure titanium has been studied as a function of protein concentration, using X‐ray photoelectron spectroscopy (XPS). The adsorption isotherm has been plotted using the increase in N 1s intensity and also by measurement in the decrease in the Ti 2p intensity as the adsorbed film reaches full coverage. It is shown that both sets of data are a good fit to the Temkin isotherm. The influence of the large size of the biomolecule is discussed and the isotherm is modified to take account of the molecular dimension according to the model proposed by Ratner and Paynter. The thicknesses of the adsorbed molecules are measured using atomic force microscopy (AFM) and it is shown that it is only when monolayer coverage has been reached that the molecules begin to take up the characteristic globular shape. Albumin reaches a coverage of 25% of a monolayer in solutions of only 10 ppb by volume, suggesting that it is easily bound to the TiO2 surface. A complete monolayer is formed at a solution concentration of 100 ppm. The carbon 1s signal is used to estimate the surface free energy at different surface coverages using the model developed by Kinloch, Kodokian and Watts. The transformation from the initial coverage of hydrophobic contamination molecules to the hydrophilic surface presented by the adsorbed albumin film takes place over a range similar to that required to form the monolayer. Copyright © 2005 John Wiley & Sons, Ltd.
Analysis of oxidation behavior under dry air of neat and Ta‐alloyed furan‐resin‐derived carbons heat treated at 3000 °C
Authors: Nakamura Kazumasa , Tanabe Yasuhiro , Suzuki Noboru , Kakihana Masato , Fukushima Manabu , Teranishi Yoshikazu , Lanticse Leslie , Yasuda Eiichi 
Published: November 2005

AbstractOxidation behavior and structural changes of furan‐resin‐derived carbons heat treated at 3000 °C were investigated at 500 and 700 °C under dry air. Thermogravimetric analysis (TGA), Raman spectroscopy and X‐ray photoelectron spectroscopy (XPS) were employed to detect and understand this behavior and the changes. Effect of tantalum on antioxidation property of Ta‐alloyed carbon was also analyzed. The neat and Ta‐alloyed carbons had insignificant weight losses even after being kept at 500 °C for 12 h, while the Ta‐alloyed carbon had weight loss lower than that of the neat carbon after being kept at 700 °C for 6 h. It has been found by XPS that oxidation involves oxygen in internal area as well as on external surface of the carbons. It was also inferred that the carbon stored with oxygen in deeper internal area was easily oxidized. Ta alloying leads to change of the state of the Fermi energy on the specimens, which may cause the antioxidation property. Copyright © 2005 John Wiley & Sons, Ltd.
X‐ray photoelectron spectroscopy and the pattern recognition method—their application to surface studies in CoPd alloys
Authors: Lesiak B. , Biliński A. , Jóźwik A. 
Published: November 2005

AbstractIn the present work, polycrystalline CoPd alloys in varying range of bulk atomic percent composition (Co30Pd70, Co50Pd50 and Co70Pd30) are investigated by means of X‐ray photoelectron spectroscopy (XPS). The results of conventional XPS quantitative multiline (ML) approach are compared to the results obtained on the basis of XPS lines shape analysis, where the selected XPS or X‐ray induced Auger electron (XAES) transitions, are processed using the pattern recognition method known as the fuzzy k‐nearest neighbour (fkNN) rule. The fkNN rule is applied to the following spectra line shapes: Pd MNV, Co 2p, Co LMM, Pd 3d and valence band, analysing electrons in a varying range of selected kinetic energies.Both methods showed the surface segregation of Pd in Co30Pd70 and Co50Pd50 alloys. The results of the ML, the binding energy shift (ΔBE) analysis and the fkNN rule remained in agreement. Discrepancies in quantitative results obtained using different approaches are discussed within the accuracy of the applied methods, differences due to mean escape depth (MED) of electrons in considered transitions, their depth distribution function, the sensitivity of electron transition line shape on the environmental change (weaker effect for the inner shell transitions, and stronger effect for the outer shell transitions and Auger electron spectroscopy (AES) electrons transitions) and the non‐uniform depth profile concentrations. Copyright © 2005 John Wiley & Sons, Ltd.
Biocatalytically Induced Formation of Cupric Ferrocyanide Nanoparticles and their Application for Electrochemical and Optical Biosensing of Glucose
Authors: Wang Joseph , Sánchez Arribas Alberto 
Published: November 2005

AbstractThe enzymatically controlled growth of cupric ferrocyanide nanoparticles in the presence of glucose oxidase, its ferricyanide electron acceptor, and copper ions is described. The biocatalytically stimulated growth of these nanoparticles on the surface of carbon‐paste electrodes results in an amplified electrochemical detection of the glucose substrate. This concept can readily be expanded for monitoring a wide range of biocatalytic processes involving the ferricyanide electron acceptor.
Ein Walfisch aus Stahl, Holz und Glas – die Fassade des Kaufhauses Peek und Cloppenburg in Köln
Authors: Helbig Thorsten , Knippers Jan , Müller Thomas 
Published: November 2005

AbstractMit dem neuen Kaufhaus Peek und Cloppenburg ist ein Bau von herausragender architektonischer Qualität mitten im Herzen der Kölner Altstadt entstanden. Seine Fassade, über die in diesem Aufsatz berichtet wird, war in vielfacher Hinsicht eine besondere Herausforderung für die Tragwerksplanung. Dies betrifft die komplexe Geometrie, die Lagerung auf dem Rohbau vor allem aber die ungewöhnliche und neuartige Kombination der Werkstoffe Stahl und Holz. Aufgelöste vertikale Holzbinder und horizontale Stahlrohre bilden mit diagonalen Stahlseilen eine freitragende Stabschale. Dazu mußten zahlreiche Konstruktionsdetails, insbesondere die Holzverbinder, erstmals gelöst werden.
Tragverhalten lösbarer Seilklemmen für Spiralseile
Authors: Bechtold Martin , Saal Helmut 
Published: November 2005

AbstractDie Mechanismen und Einflußgrößen zum Tragverhalten von Seilklemmen sind weitgehend unbekannt, und die vorhandenen Regelungen [1], [2] in der aktuellen Normung erfassen ihr Tragverhalten lediglich in Ausnahmefällen. Seilklemmen sind meistens keine standardisierten Bauteile, da die Einsatzbedingungen von Fall zu Fall stark variieren, so daß sie in der Regel für jedes Bauwerk neu entworfen und in ihrer Tragfähigkeit untersucht werden.Auf der Grundlage zahlreicher Bauteilversuche, Untersuchungen mit Finiten Elementen und analytischen Ansätzen werden die Einflüsse auf das Tragverhalten sowie die Erkenntnisse über die Größe des Klemmkraftbeiwerts, der dauerhaft vorhandenen Klemmkraft und des Reibbeiwerts dargestellt. Dies dient dem Entwurf und der Dimensionierung von Seilklemmen.
Wölbkrafttorsion von Durchlaufträgern mit konstantem Querschnitt unter Berücksichtigung sekundärer Schubverformungen
Authors: Rubin Helmut 
Published: November 2005

AbstractDie Analogie zwischen der Theorie der Wölbkrafttorsion und der Theorie II. Ordnung für den Biegestab mit Längszug gilt auch dann noch, wenn bei der Wölbkrafttorsion die Schubverformungen der sekundären Torsion und beim Biegestab die Querkraftverformungen zusätzlich berücksichtigt werden. Auf der Basis dieser Analogie wird die Dreimomentengleichung zur Berechnung von Durchlaufträgern mit konstantem Querschnitt angegeben. Es wird gezeigt, daß die sekundären Schubverformungen bei offenen Querschnitten in der Regel vernachlässigbar sind, bei geschlossenen Querschnitten aber stets berücksichtigt werden müssen. Ebenso wird gezeigt, daß bei diesen geschlossenen Querschnitten die Wölbkrafttorsion i. w. nur an “Störstellen” auftritt, dort aber Spannungen hervorruft, die gegenüber jenen der primären Torsion nicht vernachlässigbar sind.
Thermisch hoch beanspruchte Tragwerke: Spannungskategorisierung unter Einschluß thermischer Wirkungen
Authors: Hellmann Karl , Krätzig Wilfried B. 
Published: November 2005

AbstractVorhandene Spannungskategorisierungen [2], [11] unterteilen mechanische Lastspannungen hinreichend genau in primäre Spannungen, sekundäre Spannungen und Spannungsspitzen, mit jeweils unterschiedlichen zulässigen Grenzwerten. Hingegen werden thermischverursachte Spannungen nur als solche aus behinderter Wärmedehnung aufgeführt und als Sekundärspannungen bzw. als Spannungsspitzen eingeordnet. Ergänzend zu dieser Klassifizierung werden im vorliegenden Aufsatz dual zu mechanischen Primärspannungen – durch von außen einwirkende Kraftgrößen – primäre thermische Spannungen (thermomechanische Spannungen) – durch von außen einfließende instationäre Wärmeströme – berechnet und korrekt klassifiziert. Der Aufsatz weist dabei auf beobachtete Tragwerksschäden durch falsche Klassifizierung thermomechanischer Spannungen hin.
Unsymmetric bidentate ligands in metal‐catalyzed carbonylation of alkenes
Authors: Nozaki Kyoko 
Published: November 2005

AbstractCharacteristic features of unsymmetric bidentate ligands, in which the two coordination atoms are not equivalent, are reviewed with a focus on their use in metal‐catalyzed olefin carbonylations. High enantioselectivity for a variety of substrates was achieved using ligand 9 in Rh‐catalyzed hydroformylation. Unsymmetric ligand 21e shows high productivity accompanied by high regio‐ and enantioselectivities in the Pd‐catalyzed alternating copolymerization of 1‐alkene with CO. The advantages of electronic unsymmetry are demonstrated especially in the spectroscopic observation of single steps involved in catalytic cycles. © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 5: 376–384; 2005: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20046
Dihaloindium hydride as a novel reducing agent
Authors: Baba Akio , Shibata Ikuya 
Published: November 2005

AbstractDihaloindium hydrides (X2InH) are novel reducing reagents, which act in both an ionic and a radical manner. The hydrides were easily generated from InX3 and Bu3SnH to reduce a variety of functionalities such as aldehydes, ketones, enones, and imines. The combination of a phosphine and Cl2InH accomplished the selective transformation from acid chlorides to aldehydes. One‐pot treatment of Cl2InH, enones, and aldehydes achieved reductive aldol reactions, in which the predominant reduction of enones was followed by an aldol reaction between the resulting indium enolates and the remaining aldehydes. It is noteworthy that both anti‐ and syn‐selective aldols were obtained by the use of THF and an aqueous solvent, respectively. The replacement of Bu3SnH with Et3SiH as a hydride source allowed the catalytic use of InBr3 to give the syn‐selective aldols. The dehalogenation of alkyl halides was achieved by a catalytic amount of InCl3 in the presence of Bu3SnH. This procedure was applied to some representative cyclizations as radical proof. A simple and non‐toxic system, NaBH4/InCl3, also promoted dehalogenation, intramolecular cyclization, and intermolecular coupling reactions. In addition, the Et3SiH/InCl3 system was found applicable to an effective intramolecular cyclization of enynes. © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 5: 323–335; 2005: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20055