bluuebunny/crossref_metadata_2025_split huggingface dataset:
Betontechnik für die Stelen des Holocaust‐Mahnmals in Berlin
Authors: Müller Harald S. , Schlüter Franz‐Hermann 
Published: October 2005

AbstractDie 2711 Betonstelen des Holocaust‐Mahnmals in Berlin Mitte müssen hohen Anforderungen hinsichtlich ihres Erscheinungsbildes und ihrer Dauerhaftigkeit genügen. Daher sah die Ausschreibung einen zu bewehrenden Konstruktionsbeton, mit einer Mindestdruckfestigkeit von 40 N/mm2 und einer maximal zulässigen Rißbreite an der Oberfläche der Stelen von 0, 1 mm vor. Eingehende Untersuchungen zur Beanspruchung der Stelen zeigten, daß die gestellten Anforderungen wesentlich sicherer erfüllt werden können, wenn auf eine Bewehrung verzichtet wird und unerwünschte Rißbildungen allein durch betontechnologische Maßnahmen auf ein Mindestmaß beschränkt werden. Entwickelt und eingesetzt wurde schließlich ein dunkel gefärbter hochfester Beton mit selbstverdichtenden Eigenschaften.
Kontrolle der Wirksamkeit der Korrosionsschutzwirkung eines Inhibitors durch Online Monitoring
Authors: Büchler Markus , Schiegg Yves , Giessler Sabine 
Published: October 2005

AbstractDie Instandsetzung von korrosionsgeschädigten Stahlbetonbauwerken ist kosten‐ und zeitintensiv. Die klassische Vorgehensweise besteht aus dem Abtrag von karbonatisiertem oder chloridbelastetem Beton und anschließender Reprofilierung. Unter gewissen Umständen ist dies nicht möglich. So kann beispielsweise die hohe Verkehrsauslastung eine Sperrung des Bauwerks praktisch unmöglich machen. Korrosionsinhibitoren, die durch einfache Sprühapplikation auf die Oberfläche des Betons aufgetragen werden, stellen eine mögliche Alternative dar. Diese Produkte sind in den meisten Fällen jedoch erst seit wenigen Jahren auf dem Markt, und Erfahrungswerte über das Langzeitverhalten liegen noch nicht ausreichend vor. Hinzu kommt, daß bei fehlerhafter Applikation keine genügende Wirksamkeit erreicht werden kann. Durch Kombination von Anwendung und meßtechnischer Überwachung der Makroelementströme und Potentiale ist es möglich, die Wirksamkeit der getroffenen Maßnahme nachzuweisen. Die langjährigen, positiven Ergebnisse einer solchen Inhibierungsmaßnahme am Beispiel von Autobahn‐Galeriestützen werden in diesem Beitrag diskutiert.
NMR evidence of a valinomycin–proton complex
Authors: Kříž Jaroslav , Makrlík Emanuel , Vaňura Petr 
Published: October 2005

AbstractIn addition to the well‐known complexes of valinomycin with alkali metal cations, an equimolar complex of the same compound with proton was found to be formed in nitrobenzene. Hydrogen bis(1,2‐dicarbollylide) cobaltate (HDCC) was used as a proton source. According to NMR spectra, the complex formation is quantitative at proton/valinomycin molar ratios up to 1:1 but there is fast exchange of protons between coordinated and uncoordinated valinomycin molecules at lower ratios. 1H and 13C NMR spectra show a dramatic change in the valinomycin conformation during its coordination with protons, probably from a propeller‐like to a bracelet‐like form. As valinomycin is one of the well‐known ion‐carrying ionophores facilitating especially the K+ ion transport across a biological membrane, the existence of the valinomycin‐proton complex could be important in biochemistry and biology. © 2005 Wiley Periodicals, Inc. Biopolymers 81: 104–109, 2006This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
A thermodynamic study on the interaction between magnesium ion and human growth hormone
Authors: Saboury A. A. , Atri M. S. , Sanati M. H. , Moosavi‐Movahedi A. A. , Hakimelahi G. H. , Sadeghi M. 
Published: October 2005

AbstractA thermodynamic study on the interaction between magnesium ion and human growth hormone (hGH) was studied at 27°C in NaCl solution (50 mM) using different techniques. Two techniques of ionmetry using a Mg2+selective membrane electrode and isothermal titration calorimetry were applied to obtain the binding isotherm for hGHMg2+; results obtained by both techniques were found to be in good agreement. There is a set of three identical and noninteracting binding sites for magnesium ions. The intrinsic dissociation equilibrium constant and the molar enthalpy of binding are 46 μM and −17.7 kJ/mol, respectively. Temperature scanning UV‐visible spectroscopy was applied to elucidate the effect of Mg2+ binding on the protein stability, and circular dichroism (CD) spectroscopy was used to show the structural change of hGH due to the metal ion interaction. Magnesium ion binding increased the protein thermal stability by increasing the α‐helix content as well as decreasing both β and random coil structures. However, the secondary structural change of the protein returns to its native form, including a small change in the tertiary structure, in high concentrations of magnesium ion. © 2005 Wiley Periodicals, Inc. Biopolymers 81: 120–126, 2006This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Detailed Structural Examinations of Covalently Immobilized Gold Nanoparticles onto Hydrogen‐Terminated Silicon Surfaces
Authors: Yamanoi Yoshinori , Shirahata Naoto , Yonezawa Tetsu , Terasaki Nao , Yamamoto Noritaka , Matsui Yoshitaka , Nishio Kazuyuki , Masuda Hideki , Ikuhara Yuichi , Nishihara Hiroshi 
Published: October 2005

AbstractThe modification of flat semiconductor surfaces with nanoscale materials has been the subject of considerable interest. This paper provides detailed structural examinations of gold nanoparticles covalently immobilized onto hydrogen‐terminated silicon surfaces by a convenient thermal hydrosilylation to form SiC bonds. Gold nanoparticles stabilized by ω‐alkene‐1‐thiols with different alkyl chain lengths (C3, C6, and C11), with average diameters of 2–3 nm and a narrow size distribution were used. The thermal hydrosilylation reactions of these nanoparticles with hydrogen‐terminated Si(111) surfaces were carried out in toluene at various conditions under N2. The obtained modified surfaces were observed by high‐resolution scanning electron microscopy (HR‐SEM). The obtained images indicate considerable changes in morphology with reaction time, reaction temperature, as well as the length of the stabilizing ω‐alkene‐1‐thiol molecules. These surfaces are stable and can be stored under ambient conditions for several weeks without measurable decomposition. It was also found that the aggregation of immobilized particles on a silicon surface occurred at high temperature (> 100 °C). Precise XPS measurements of modified surfaces were carried out by using a Au–S ligand‐exchange technique. The spectrum clearly showed the existence of SiC bonds. Cross‐sectional HR‐TEM images also directly indicate that the particles were covalently attached to the silicon surface through SiC bonds.
An accurate numerical solution algorithm for 3D velocity–vorticity Navier–Stokes equations by the DQ method
Authors: Lo D. C. , Young D. L. , Murugesan K. 
Published: October 2005

AbstractA numerical scheme based on a differential quadrature (DQ) method is discussed for the solution of three‐dimensional velocity–vorticity Navier–Stokes equations. Numerical solutions of the six field variables, three velocities and three vorticities are obtained by adopting a coupled numerical solution procedure. Hence, it is required to specify only the velocity boundary conditions, whereas the vorticity values at the boundary are computed implicitly, thus without seeking boundary vorticity values by an iterative procedure followed in other explicit numerical schemes. Since the DQ method approximates a given differential operator with higher‐order polynomials, the vorticity definition is accurately enforced at the boundary. This ensures a divergence‐free solution for the flow field. Flow simulations obtained for a lid‐driven cubic cavity for Stokes flow and Re=100, 400 and 1000 show excellent agreements with other numerical schemes. A grid independence study demonstrates that the present numerical scheme could predict benchmark solutions with coarser meshes than other numerical schemes. Copyright © 2005 John Wiley & Sons, Ltd.
Systematic Control of Nonlinear Optical Processes Using Optimally Shaped Femtosecond Pulses
Authors: Lozovoy Vadim V. , Dantus Marcos 
Published: October 2005

AbstractThis article reviews experimental efforts to control multiphoton transitions using shaped femtosecond laser pulses, and it lays out the systematic study being followed by us for elucidating the effect of phase on nonlinear optical laser–molecule interactions. Starting with a brief review of nonlinear optics and how nonlinear optical processes depend on the electric field inducing them, a number of conclusions can be drawn directly from analytical solutions of the equations. From a Taylor expansion of the phase in the frequency domain, we learn that nonlinear optical processes are affected only by the second‐ and higher‐order terms. This simple result has significant implications on how pulse‐shaping experiments are to be designed. If the phase is allowed to vary arbitrarily as a continuous function, then an infinite redundancy that arises from the addition of a linear phase function across the spectrum with arbitrary offset and slope could prevent us from carrying out a closed‐loop optimization experiment. The early results illustrate how the outcome of a nonlinear optical transition depends on the cooperative action of all frequencies in the bandwidth of a laser pulse. Maximum constructive or destructive interference can be achieved by programming the phase using only two phase values, 0 and π. This assertion has been confirmed experimentally, where binary phase shaping (BPS) was shown to outperform other alternative functions, sometimes by at least on order of magnitude, in controlling multiphoton processes. Here we discuss the solution of a number of nonlinear problems that range from narrowing the second harmonic spectrum of a laser pulse to optimizing the competition between two‐ and three‐photon transitions. This Review explores some present and future applications of pulse shaping and coherent control.
Sc3N@C80: Computations on the Two‐Isomer Equilibrium at High Temperatures
Authors: Slanina Zdeněk , Nagase Shigeru 
Published: October 2005

AbstractReported herein are computations on the relative concentrations of the two experimentally known isomers of Sc3N@C80 , that is, those produced by encapsulation of Sc3N in two particular C80 cages that obey the isolated‐pentagon rule, namely, with Ih and D5h symmetries. The calculations are based on density functional methods and have been carried out using the Gibbs energy over a broad temperature interval. It has been computed that, if a relatively free motion of the encapsulate inside the cages is allowed, the observed populations of 10 and 17 % for the D5h Sc3N@C80 species are reached at temperatures of 2100 and 2450 K, respectively. The inclusion of the entropy term is essential as, if it is neglected, the D5h Sc3N@C80 population at a temperature of 2100 K would be a mere 1 %, owing to the relatively large interisomeric separation potential energy of 19 kcal mol−1.
Experimental and Computational Studies of the Phenyl Radical Reaction with Propyne
Authors: Tokmakov Igor V. , Park Joonbum , Lin Ming Chang 
Published: October 2005

AbstractThe kinetics for the gas‐phase reaction of phenyl radical with propyne has been measured by cavity ring‐down spectrometry (CRDS), and the mechanism and initial product branching have been elucidated with the help of quantum chemical calculations. Absolute rate constants measured by the CRDS technique can be expressed by the following Arrhenius equation: (k/cm3 mol−1 s−1): kpropyne(T=301–428 K)=(3.68±0.92)×1011exp[−(1685±80)/T]. The experiment is unable to distinguish between the possible reactive channels, but theory indicates that phenyl radicals preferably add to the unsaturated terminal carbon atom in propyne under our experimental conditions. Theoretical kinetic calculations, employing high‐level G2M(RCC, RMP2) and G3 energetic and IRCMax(RCCSD(T)//B3LYP‐DFT) molecular parameters, reproduce the total experimental rate constants within a factor of three. Calculated total and branching rate constants are provided for high‐T kinetic modeling. Addition reactions of phenyl to C3H4 are estimated to be less important molecular‐growth pathways in high‐T conditions (T>1000 K) in comparison to the C6H5+C2H2 reaction.
SiC Linked Organic Monolayers on Crystalline Silicon Surfaces as Alternative Gate Insulators
Authors: Faber Erik J. , de Smet Louis C. P. M. , Olthuis Wouter , Zuilhof Han , Sudhölter Ernst J. R. , Bergveld Piet , van den Berg Albert 
Published: October 2005

AbstractHerein, the influence of silicon surface modification via SiCnH2n+1 (n=10,12,16,22) monolayer‐based devices on p‐type 〈100〉 and n‐type 〈100〉 silicon is studied by forming MIS (metal–insulator–semiconductor) diodes using a mercury probe. From current density–voltage (J–V) and capacitance–voltage (C–V) measurements, the relevant parameters describing the electrical behavior of these diodes are derived, such as the diode ideality factor, the effective barrier height, the flatband voltage, the barrier height, the monolayer dielectric constant, the tunneling attenuation factor, and the fixed charge density (Nf). It is shown that the J–V behavior of our MIS structures could be precisely tuned via the monolayer thickness. The use of n‐type silicon resulted in lower diode ideality factors as compared to p‐type silicon. A similar flatband voltage, independent of monolayer thickness, was found, indicating similar properties for all silicon–monolayer interfaces. An exception was the C10‐based monolayer device on p‐type silicon. Furthermore, low values of Nf were found for monolayers on p‐type silicon (≈6×1011 cm−2). These results suggest that SiC linked monolayers on flat silicon may be a viable material for future electronic devices.
Particle Distribution in a Microporous Material: Theoretical Concept
Authors: Meyer Marc , Currao Antonio , Calzaferri Gion 
Published: October 2005

AbstractParticle distribution and exchange equilibria in a microporous host material, built up of equivalent particle sites, which are grouped in larger subsets, are described. Simplified descriptions evolve from the exact formulae in the thermodynamic limit. We find that, for example, a single zeolite A nanocrystal consisting of about 1000 pseudo‐unit‐cells fixes a lower limit for the use of the approximate formula describing particle distribution. A rational selectivity coefficient, which is approximately constant over the whole exchange range, only results if a single zeolite crystal consists of one million pseudo‐unit‐cells or more, or if a sufficiently large number of smaller crystals is considered. On the basis of the statistical particle distribution model, a closed, simple formula for the ion‐exchange isotherm is then derived, which is valid for systems involving a variable number of coupled‐exchange reactions. Its similarity to the Langmuir isotherm is discussed. The theory on ion‐exchange equilibria is used to derive formulae for the change of free‐energy, enthalpy, and entropy occurring in coupled ion‐exchange reactions. The findings, though applicable to virtually any particle exchanging system with the structural properties described above, are applied to zeolite A, since this material can be treated as a nearly ideal model. The results derived can straightforwardly be used to evaluate experimental data quantitatively, since the common inequivalence of the host sites can be taken into account.
NMR Spectroscopy Investigation of the Cooperative Nature of the Internal Rotational Motions in Acetophenone
Authors: De Luca Giuseppina , Longeri Marcello , Pileio Giuseppe , Lantto Perttu 
Published: October 2005

AbstractThe proton NMR spectrum of the doubly enriched acetophenone‐carbonyl,methyl‐13C2 isotopomer dissolved in a liquid‐crystalline solvent (LXNMR) was analyzed to yield a data set of 19 dipolar couplings. The presence of so many couplings, and in particular the dependence of some of them on the acetyl carbons enabled the investigation of the structure of the acetyl moiety and of possible cooperative motions about the aryl–carbonyl and carbonyl–methyl bonds. Methodological aspects, and approximations relating to the application of the vibrational correction procedure in the presence of large‐amplitude torsional motions, are discussed. Results show that it is possible to discriminate between a continuous and a discrete conformer distribution about the angle ϕ1 but not among a few proposed continuous shapes of Uiso({ϕ}). In this study, the use of dipolar couplings with a non‐negligible contribution from the indirect spin–spin coupling tensor J, (${D_{{\rm{C8C9}}} }$ in our case), for structural determination is extended from rigid to flexible molecules. The ${{1 \over 2}J_{{\rm{C8C9}}}^{{\rm{aniso}}} }$ contribution was derived theoretically using the density functional theory linear response (DFT‐LR) first‐principles calculation of the JC8C9 spin–spin coupling tensor.
Early Stages of ZnS Nanoparticle Growth Studied by In‐Situ Stopped‐Flow UV Absorption Spectroscopy
Authors: Tiemann Michael , Weiß Özlem , Hartikainen Juha , Marlow Frank , Lindén Mika 
Published: October 2005

AbstractThe early stages of ZnS nanoparticle growth from supersaturated solution are investigated in situ by stopped‐flow UV absorption spectroscopy with a time resolution of 1.28 ms. A model for data analysis is suggested which makes it possible to study both the average particle radius and the concentration. The average radii lie in the sub‐nanometer range. During the first 40 ms, growth is predominantly governed by ripening.
Exploiting the innate immune system to control allergic asthma
Authors: Dombrowicz David 
Published: October 2005

AbstractNKT cells are key actors at the interface between innate and acquired immunity. Indeed, upon activation by glycolipid antigens, they rapidly secrete both Th1 and Th2 cytokines, which affects the development of later immune responses. Previous studies have shown that NKT cells are essential for the development of allergic asthma, a prototypical Th2‐mediated pathology. By contrast, three papers, two of which are published in this issue of the European Journal of Immunology, demonstrate, in mouse models, that treatment with α‐galactosylceramide, a specific NKT ligand, inhibits most of the parameters associated with the disease, including airway hyperreactivity, eosinophilia and IgE production. Increased IFN‐γ synthesis, rather than regulatory IL‐10, accounts for this paradoxical effect.See accompanying articles: http://dx.doi.org/10.1002/eji.200525994 and http://dx.doi.org/10.1002/eji.200535268
Time‐dependent natural convection in a square cavity: Application of a new finite volume method
Authors: Mahdi Hashim S. , Kinney Robert B. 
Published: October 2005

AbstractA new finite volume (FV) approach with adaptive upwind convection is used to predict the two‐dimensional unsteady flow in a square cavity. The fluid is air and natural convection is induced by differentially heated vertical walls. The formulation is made in terms of the vorticity and the integral velocity (induction) law. Biquadratic interpolation formulae are used to approximate the temperature and vorticity fields over the finite volumes, to which the conservation laws are applied in integral form. Image vorticity is used to enforce the zero‐penetration condition at the cavity walls. Unsteady predictions are carried sufficiently forward in time to reach a steady state. Results are presented for a Prandtl number (Pr) of 0‐71 and Rayleigh numbers equal to 103, 104 and 105. Both 11 × 11 and 21 × 21 meshes are used. The steady state predictions are compared with published results obtained using a finite difference (FD) scheme for the same values of Pr and Ra and the same meshes, as well as a numerical bench‐mark solution. For the most part the FV predictions are closer to the bench‐mark solution than are the FD predictions.
Finite element analysis of convective heat transfer in porous media
Authors: Rajamani Rajesh , Srinivas C. , Seetharamu K. N. 
Published: October 2005

AbstractThe finite element method is used to analyse convective heat transfer in a porous medium. Convection past a vertical surface embedded in the medium and convection in a confined porous medium enclosure are analysed using the above method. The results are compared with those available in the literature and the agreement is found to be good. The method is applicable for two‐dimensional analysis in a porous body of any arbitrary shape. The restriction of the boundary layer assumption is relaxed.
Finite element solution of the Navier–Stokes equations by a velocity–vorticity method
Authors: Guevremont G. , Habashi W. G. , Hafez M. M. 
Published: October 2005

AbstractA velocity–vorticity formulation of the Navier–Stokes equations is presented as an alternative to the primitive variables approach. The velocity components and the vorticity are solved for in a fully coupled manner using a Newton method. No artificial viscosity is required in this formulation. The pressure is updated by a method allowing natural imposition of boundary conditions. Incompressible and subsonic results are presented for two‐dimensional laminar internal flows up to high Reynolds numbers.
Analysis of plane and axisymmetric flows of incompressible fluids with the stream tube method: Numerical simulation by trust‐region optimization algorithm
Authors: Clermont J. R. , De La Lande M. E. , Dinh T. Pham , Yassine A. 
Published: October 2005

AbstractNew concepts for the study of incompressible plane or axisymmetric flows are analysed by the stream tube method. Flows without eddies and pure vortex flows are considered in a transformed domain where the mapped streamlines are rectilinear or circular. The transformation between the physical domain and the computational domain is an unknown of the problem. In order to solve the non‐linear set of relevant equations, we present a new algorithm based on a trust region technique which is effective for non‐convex optimization problems. Experimental results show that the new algorithm is more robust compared to the Newton‐Raphson method.
Differential‐equation‐based representation of truncation errors for accurate numerical simulation
Authors: MacKinnon Robert J. , Johnson Richard W. 
Published: October 2005

AbstractHigh‐order compact finite difference schemes for two‐dimensional convection‐diffusion‐type differential equations with constant and variable convection coefficients are derived. The governing equations are employed to represent leading truncation terms, including cross‐derivatives, making the overall O(h4) schemes conform to a 3 × 3 stencil. We show that the two‐dimensional constant coefficient scheme collapses to the optimal scheme for the one‐dimensional case wherein the finite difference equation yields nodally exact results. The two‐dimensional schemes are tested against standard model problems, including a Navier‐Stokes application. Results show that the two schemes are generally more accurate, on comparable grids, than O(h2) centred differencing and commonly used O(h) and O(h3) upwinding schemes.