bluuebunny/crossref_metadata_2025 huggingface dataset:
Absolute cross sections of ozone at atmospheric temperatures for the Wulf and the Chappuis bands
Authors: Helou Z. El , Churassy S. , Wannous G. , Bacis R. , Boursey E.
Published: June 2005

Ozone absorption constitutes a variable background against which measurement of pollution is observed from satellites by the solar occultation technique. The temperature-altitude gradient of ozone spans the range 180–340K. Laboratory measurements of ozone absorption at temperatures across this range are needed to calibrate spectroscopic remote sensing, but have yielded results in substantial disagreement with each other. This paper presents the first measurements of the variation of absorption cross-sections of ozone at temperatures from 144to300K over the 9250–18 500cm−1 spectral region.
A grounded-load charge amplifier for reducing hysteresis in piezoelectric tube scanners
Authors: Fleming A. J. , Moheimani S. O. R.
Published: June 2005

In this paper, a charge amplifier adapted for piezoelectric tube scanners is presented. Previous problems involved with the implementation of such amplifiers are resolved to provide dc accurate performance with zero voltage drift. In our experiment, hysteresis was reduced by 89% when compared to a voltage amplifier.
Direct computer simulation of water-mediated force between supported phospholipid membranes
Authors: Pertsin Alexander , Platonov Dmitry , Grunze Michael
Published: June 2005

The grand canonical Monte Carlo technique is used to calculate the water-mediated force operating between two supported 1,2-dilauroyl-DL-phosphatidylethanolamine (DLPE) membranes in the short separation range. The intra- and intermolecular interactions in the system are described with a combination of an AMBER-based force field for DLPE and a TIP4P model for water. The long range contributions to the electrostatic interaction energy are treated in the dipole-dipole group-based approximation. The total water-mediated force is analyzed in terms of its hydration component and the component due to the direct interaction between the membranes. The latter is, in addition, partitioned into the electrostatic, van der Waals, and steric repulsion contributions to give an idea of their relative significance in the water-mediated interaction of the membranes.
Observation of persistent edge current driven by coaxial helicity Injection
Authors: Mueller D. , Nelson B. A. , Hamp W. T. , Redd A. J. , Jarboe T. R. , O’Neill R. G. , Smith R. J.
Published: June 2005

Coaxial Helicity Injection (CHI) has been used on the National Spherical Torus Experiment [Ono et al., Nucl. Fusion 40, 557 (2000)], the Helicity Injected Torus (HIT) [Nelson et al., Phys. Rev. Lett. 72, 3666 (1994)] and HIT-II [Jarboe et al., Phys. Plasmas 5, 1807 (1998)] to initiate plasma and to drive up to 400 kA of toroidal current. On HIT-II, CHI initiated discharges have been successfully coupled to Ohmic sustainment [Raman et al., Phys. Plasmas 11, 2565 (2004)]. This paper presents the first results on the use of CHI to demonstrate the persistence of edge current drive in a pre-established single null diverted inductive discharge. Edge current drive has the potential to improve plasma stability limits [Menard et al., Nucl. Fusion 37, 595 (1997)]. While most current drive methods drive current in the interior of the plasma, CHI is well suited for driving current in the edge plasma.
Effect of media overcoat on van der Waals interaction at the head–disk interface
Authors: Dagastine Raymond R. , White Lee R. , Jones Paul M. , Hsia Yiao-Tee
Published: June 2005

A multilayer Lifshitz calculation of van der Waals interactions at the magnetic storage head–disk interface is presented. The calculation of the Hamaker function for model multilayer film stacks that incorporate different media overcoat materials is obtained. These functions allow the comparison of interfacial forces when the media is coated with diamondlike carbon, with and without the inclusion of hydrogen and annealing, and SiNx overcoat films. A significant difference, ∼30%, in the magnitude of the interfacial force with the different overcoats is calculated.
Effect of rotational energy on the reaction Li+HF(υ=,j)→LiF+H: An experimental and computational study
Authors: Bobbenkamp Rolf , Paladini Alessandra , Russo Andrea , Loesch H. J. , Menéndez Marta , Verdasco Enrique , Aoiz F. J. , Werner H.-J.
Published: June 2005

In a crossed molecular-beam study we have measured angular and time-of-flight distributions of the product LiF from the reaction Li+HF(υ=0)→LiF+H at various collision energies ranging from 97to363meV for three markedly different rotational state distributions of HF obtained at nozzle temperatures close to 315, 510, and 850K. Particularly, for the low and intermediate collision energies we observe significant effects of the varying j-state populations on the shape of the product angular distributions. At 315K an additional feature appears in the angular distributions which is interpreted as being due to scattering from HF dimers. The experimental data are compared with simulations of the monomer reaction based on extensive quasiclassical trajectory calculations on a new state-of-the-art ab initio potential energy surface. We find an overall good agreement between the theoretical simulations and the experimental data for the title reaction, especially at the highest HF nozzle temperature.
Three-dimensional solutions for coating flow on a rotating horizontal cylinder: Theory and experiment
Authors: Evans P. L. , Schwartz L. W. , Roy R. V.
Published: June 2005

We present three-dimensional numerical simulations of the flow of a thin liquid coating on a rotating horizontal right circular cylinder. The liquid motion is described using a lubrication model. The model evolution equation is discretized and solved numerically using an alternating-direction implicit algorithm. The cylinder rotates about its axis, carrying liquid around its circumference, resulting in the formation of a relatively thick coating where the cylinder surface moves upward. For coatings which are initially nearly uniform along the cylinder axis, this results in a ridge of liquid aligned with the cylinder axis. Over time, this ridge may break up into one of several possible configurations, including drops near the underside, and rings enveloping the cylinder. Simulations show that on larger cylinders, under certain circumstances this ridge may develop undulations which grow to form long fingers. These fingers drain down the cylinder. The simulation results are compared with a simple laboratory experiment, which exhibits similar fingering.
Instrument for electrohydrodynamic print-patterning three-dimensional complex structures
Authors: Wang D. Z. , Jayasinghe S. N. , Edirisinghe M. J.
Published: June 2005

A print-patterning instrument coupling electrohydrodynamics and servo and stepper motor motion has been developed. It has been used to pattern and form a 10mm×30mm rectangular walled container from zirconia. The incorporation of electrohydrodynamics allows the generation of finer droplets, compared with ink-jet technology, from a concentrated two-phase medium. The precision servo/stepper system consists of a three-axis motion planner, which is computer controlled and allows three cradles to be in motion according to a predetermined sequence created on any computer aided design package. The problems encountered in forming three-dimensional (3D) structures using this method are explained and possible solutions incorporating future work are discussed. This instrument has the potential of being developed into a powerful device for 3D solid freeform fabrication of structural, functional, and biological structures.
Effects of compositional defects on small polaron hopping in micas
Authors: Rosso Kevin M. , Ilton Eugene S.
Published: June 2005

Hartree–Fock calculations and electron transfer (ET) theory were used to model the effects of compositional defects on ET in the brucite-like octahedral sheet of mica. ET was modeled as an FeII∕III valence interchange reaction across shared octahedral edges of the M2-M2 iron sublattice. The model entails the hopping of localized electrons and small polaron behavior. Hartree–Fock calculations indicate that substitution of F for structural OH bridges increases the reorganization energy λ, decreases the electronic coupling matrix element VAB, and thereby substantially decreases the hopping rate. The λ increase arises from modification of the metal-ligand bond force constants, and the VAB decrease arises from reduction of superexchange interaction through anion bridges. Deprotonation of an OH bridge, consistent with a possible mechanism of maintaining charge neutrality during net oxidation, yields a net increase in the ET rate. Although substitution of Al or Mg for Fe in M1 sites distorts the structure of adjacent Fe-occupied M2 sites, the distortion has little net impact on ET rates through these M2 sites. Hence the main effect of Al or Mg substitution for Fe, should it occur in the M2 sublattice, is to block ET pathways. Collectively, these findings pave the way for larger-scale oxidation/reduction models to be constructed for realistic, compositionally diverse micas.
Ultrafast selected energy x-ray absorption spectroscopy investigations of Ni and Zn species
Authors: Shan Fang , Guo Ting
Published: June 2005

The results of ultrafast selected energy x-ray absorption spectroscopy (USEXAS) investigations of Ni and Zn species are presented. The USEXAS measurements described here employed characteristic x-ray radiation of Lα and Lβ from an ultrafast laser-driven W x-ray target to probe the K absorption edges of Ni and Zn, respectively. Static x-ray absorption edge spectra of six Ni and Zn species in either solid or solution form were obtained. Simulations of near-edge x-ray absorption spectra of these Ni and Zn species were carried out with FEFF. The results of USEXAS measurements were in general agreement with the theoretically simulated spectra and those measured with synchrotron x-ray radiation.
Wetting kinetics of films containing nonadsorbing polymers
Authors: Saritha S. , Zhang Xianzhong , Neogi P.
Published: June 2005

Kinetics of wetting by a polymer solution have been studied theoretically for a film pinned to a slot. The fluid mechanical equations have been solved using a numerical scheme. The role of polymers appears in the disjoining pressure in the model. The spreading kinetics are observed to follow a power law: a power of 14 is observed at short times due to the Laplace pressure, and 12 at large times under the Hamaker part of the disjoining pressure at very large times and with no equilibration. It is argued and demonstrated that techniques which have low resolutions such as microscopy will measure quite different kinetics: at short times a power of 14 as for wetting liquids and then a sudden equilibration as reported in these experiments. It is also argued on the basis of steric exclusion, and quantified in the disjoining pressure, that the behavior returns to that of wetting liquids when the polymer molecular weight becomes very high, as also observed in the experiments. Examples of how these features can find practical applications, and hence, the importance of use of polymers as additives are given.
Studies of silicon dihydride and its potential role in light-induced metastability in hydrogenated amorphous silicon
Authors: Abtew T. A. , Drabold D. A. , Taylor P. C.
Published: June 2005

Recent nuclear magnetic resonance experiments on protons in hydrogenated amorphous silicon (a-Si:H) by T. Su, P. C. Taylor, G. Ganguly, and D. E. Carlson [Phys. Rev. Lett. 89, 015502 (2002)] have shown that light exposure leads to structures involving two protons separated by 2.3±0.2Å. In this report, using supercell models of a-Si:H, we show that SiH2 configurations in the solid state are consistent with these observations. We find an average proton distance of 2.39Å for SiH2 structures considered for four different configurations. We also find that the details of basis set and density functional are important for accurately representing these structures.
A new ab initio potential-energy surface of HO2(X2A″) and quantum studies of HO2 vibrational spectrum and rate constants for the H+O2↔O+OH reactions
Authors: Xu Chuanxiu , Xie Daiqian , Zhang Dong Hui , Lin Shi Ying , Guo Hua
Published: June 2005

A new global potential-energy surface for the ground electronic state of HO2(X2A″) has been developed by three-dimensional cubic spline interpolation of more than 15 000 ab initio points, which were calculated at the multireference configuration-interaction level with Davidson correction using the augmented correlation-consistent polarized valence quadruple zeta basis set. Low-lying vibrational states were obtained in this new potential using the Lanczos method and assigned. The calculated vibrational frequencies are in much better agreement with the available experimental band origins than those obtained from a previous potential. In addition, rate constants for the H+O2↔O+OH reactions were obtained using a wave-packet-based statistical model. Reasonably good agreement with experimental data was obtained. These results demonstrate the accuracy of the potential.
Spectral features of LO phonon sidebands in luminescence of free excitons in GaN
Authors: Xu S. J. , Li G. Q. , Xiong S. -J. , Tong S. Y. , Che C. M. , Liu W. , Li M. F.
Published: June 2005

In the paper a combined experimental and theoretical investigation of the longitudinal optical phonon sidebands (PSBs) in the luminescence of free excitons in GaN at moderately high temperatures was reported. The spectral features, including line broadening, shift, and asymmetry of the one- and two-phonon PSBs, were revealed both experimentally and theoretically. It is found that the linewidth of the one-phonon PSB is surprisingly always larger than that of the two-phonon PSB in the interested temperature range. Moreover, the thermal broadening rates of the one- and two-phonon PSBs are considerably different. We adopted the Segall–Mahan theory [B. Segall and G. D. Mahan, Phys. Rev. 171, 935 (1968)] to compute the PSB spectra of the free excitons in GaN. Only one adjustable parameter, the effective mass of the holes, was used in the calculations. For the one-phonon PSB, an excellent agreement between theory and experiment is achieved when an adequate effective mass of the holes was used.
Time-gated imaging for multifocus second-harmonic generation microscopy
Authors: Kobayashi Minoru , Fujita Katsumasa , Nakamura Osamu , Kawata Satoshi
Published: June 2005

We developed a scanning second-harmonic generation (SHG) microscope with a time-gated image intensifier. The combination of a microlens array scanner and the gated image intensifier allows us to perform simultaneous time-resolved detection of SHG at multiple positions in a sample. By tuning the time delay of the gated detection from pulsed laser illumination by a mode-locked Ti:sapphire laser, background noise originating from the image intensifier dark current, fluorescence from the sample, and stray light are effectively reduced.
Physical and electrical characteristics of atomic-layer-deposited hafnium dioxide formed using hafnium tetrachloride and tetrakis(ethylmethylaminohafnium)
Authors: Triyoso Dina H. , Hegde Rama I. , White Bruce E. , Tobin Philip J.
Published: June 2005

Physical and electrical characteristics of atomic-layer-deposited HfO2 deposited using hafnium tetrachloride (HfCl4) and tetrakis[ethylmethylaminohafnium] (TEMAHf) precursors were investigated. The oxidant used for the solid HfCl4 is water, while ozone (O3) is used to oxidize the liquid TEMAHf. Physical properties of these dielectric films were studied by ellipsometry, atomic force microscopy, x-ray diffraction (XRD), secondary-ion-mass spectrometry (SIMS), and transmission electron microscopy. A linear growth rate is observed for the HfO2 deposited using both types of precursors. The HfO2 deposited using TEMAHf has a growth rate of ∼0.8Å∕cycle compared to ∼0.5Å∕cycle for HfO2 deposited using HfCl4. The early growth characteristics of these films as studied by time-of-flight SIMS were found to be similar. The HfO2 deposited by HfCl4 is smoother and denser than HfO2 deposited by TEMAHf. Higher-temperature anneals resulted in significant changes in surface morphology and an increase in roughness of the dielectric films. XRD analysis revealed that after 900 °C annealing, both HfO2 films become monoclinic with differences in preferred orientation. Both types of precursors yielded HfO2 transistors with comparable electrical characteristics. However, the peak transconductance (Gm) degradation for the TEMAHf–HfO2 devices is significantly larger compared to that produced with HfCl4–HfO2. The dielectric constant (k) value for HfCl4–HfO2 films is higher compared to that of the TEMAHf–HfO2 films. The possible reasons for the peak Gm degradation of the TEMAHf–HfO2 films and the observed higher k values for the HfCl4–HfO2 films are discussed in the paper.
Clamp-type pressure cell for full structure determination of molecular single crystals up to 1.5GPa
Authors: Hasegawa Tatsuo , Kumai Reiji , Takahashi Yukihiro , Tokura Yoshinori , Sawa Hiroshi
Published: June 2005

A pressure cell designed for full structure determination of molecular single crystals under hydrostatic pressure ranging up to 1.5GPa is described. We equipped a Teflon™-sealed clamp-type pressure cell with cylindrical beryllium windows which enables us to cover wide Bragg angles over Δ(2θ)∼120°. The cell allows us to utilize the commercial crystallographic software package for full structure determination with use of the oscillation photographs. For low-temperature experiments, pressure is calibrated in the cell filled with Daphne 7373 oil by measuring the change in the lattice parameters of an NaCl single crystal. An example is presented for the analyses of a molecular single crystal with and without the pressure cell.
Cryogenic direct current superconducting quantum interference device readout circuit
Authors: Mück Michael , Korn Matthias , Mugford C. G. A. , Kycia J. B.
Published: June 2005

We have designed and tested a superconducting quantum interference device (SQUID) readout circuit, which can be operated at liquid helium temperatures. Although room-temperature SQUID electronics perform well, it is sometimes desirable to keep the wires between SQUID, readout electronics, and feedback coil as short as possible to minimize phase shifts and time delays. Cooling the readout circuit to low temperatures can also decrease its thermal noise. Our readout circuit uses conventional ac-flux modulation, which significantly reduces low frequency excess noise and drift in the preamplifier. In this case, simple complementary metal–oxide–semiconductor circuits with low power dissipation can be used as amplifier, phase-sensitive detector and integrator. The power dissipation of the complete readout is less than 15mW at 5V supply voltage.
Broadband microwave spectroscopy in Corbino geometry for temperatures down to 1.7 K
Authors: Scheffler Marc , Dressel Martin
Published: June 2005

We present a broadband microwave spectrometer covering the range from 45 MHz up to 20 GHz (in some cases up to 40 GHz) which employs the Corbino geometry, meaning that the flat sample terminates the end of a coaxial transmission line. This setup is optimized for low-temperature performance (temperature range 1.7–300 K) and for the study of highly conductive samples. The actual sensitivity in reflection coefficient can be as low as 0.001, leading to a resolution of 10% in absolute values of the impedance or complex conductivity. For optimum accuracy a full low-temperature calibration is necessary; therefore up to three calibration measurements (open, short, and load) are performed at the same temperature as the sample measurement. This procedure requires excellent reproducibility of the cryogenic conditions. We compare further calibration schemes based on just a single low-temperature calibration measurement or employing a superconducting sample as a calibration standard for its normal state, and we document the capability of the instrument with test measurements on metallic thin films. Finally we apply the spectrometer to thin films of a heavy-fermion compound as an example for a strongly correlated electron system.
Spatial-temporal modeling for electrical impedance imaging of a mixing process
Authors: West R. M. , Meng S. , Aykroyd R. G. , Williams R. A.
Published: June 2005

The use of electrical tomography techniques for process visualization and investigation is a well-known example of a nonlinear, ill-posed, and underdetermined inverse problem. Hence stable and reliable solution is not possible using measured data alone, but requires regularization through prior information. The rôle of a Bayesian approach is therefore of fundamental importance, and when coupled with Markov chain Monte Carlo (MCMC) sampling, it can provide valuable statistical information about solution behavior and reliability, which is in contrast to most current approaches which provide only a single image reconstruction with unquantified errors. For many applications of dynamic electrical impedance imaging, some degree of both spatial and temporal smoothness is expected. Often temporal smoothness is ignored and only spatial smoothing is used. In the current application, the addition of an aliquot to a mixing vessel, smoothness is not appropriate prior information. Instead an aliquot prior is proposed, parameterized in terms of location, size, and resistivity. This approach leads to data-driven and adaptive smoothing, in contrast to the more usual global smoothing of standard regularization methods. Of further interest is the inclusion of temporal prior information: it is known that the aliquot moves and disperses in a specific manner. With this added temporal information, imaging is improved as are derived process parameters.
Dielectric∕piezoelectric resonance in high-strain Pb(Mg1∕3Nb2∕3)1−xTixO3 crystals
Authors: Tu Chi-Shun , Chien R. R. , Schmidt V. H. , Wang F.-T. , Hsu W.-T. , Tseng C.-T. , Shih C. C.
Published: June 2005

This work presents dielectric resonance in Pb(Mg1∕3Nb2∕3)1−xTixO3 crystals after electric (E)-field poling, which is crucial for piezoelectric applications. Dielectric permittivity has been measured as functions of temperature, frequency, poling E-field strength, and Ti content (x=25% and 34%). Frequency-dependent dielectric spectroscopy after poling exhibits multiple piezoelectric resonances between 0.2 and 1MHz, and can be described by the forced-damped-oscillator model. The resonant spectra show significant changes while phase transitions are taking place.
Relationship between corotating vortex-pair equilibria and a single vortex in an external deformation field
Authors: Ehrenstein Uwe , Le Dizès Stéphane
Published: June 2005

Two-dimensional corotating vortex pairs are computed as equilibrium solutions of the Euler equations and the influence of one vortex on the other is characterized in terms of a deformation field acting on an isolated vortex region. It is shown, by computing equilibrium states for a single vortex within an equivalent strain field, that the external rotating strain accounts for the elliptic deformation of the streamlines near the center of each vortex. Critical states, as a function of the strain rate, are reached when stagnation points start to penetrate the vortex regions at the outer boundary. While critical states for a single vortex within a uniform external rotating strain field consist of elliptical corner solutions, the vortex shapes lose the elliptical symmetry in the corotating case. We show that these asymmetric equilibrium states can be captured by a single vortex model if we consider higher order terms in the deformation field. We also demonstrate that the critical strain rates are of the same order of magnitude for both the single-vortex model and the interacting vortex pair.
Turbulent patches in a stratified shear flow
Authors: Fernando H. J. S.
Published: June 2005

Turbulence measurements within an artificially generated turbulent patch embedded in a stratified shear flow are presented. The results indicate that the enhanced patch growth that has been observed at background gradient Richardson numbers on the order unity can be attributed to the onset of shear-induced mixing at the patch boundaries rather than enhanced interaction between turbulence and shear that causes increased turbulence levels within the patch.
The physical mechanism of symmetric vortex merger: A new viewpoint
Authors: Huang Mei-Jiau
Published: June 2005

The physical mechanism of symmetric vortex merger is investigated in use of a resurrected core-spreading vortex method. By taking advantage of the Lagrangian characteristics of the vortex method, both Eulerian and Lagrangian flow structures are obtained and used to explore the cause of merger. The simulation results suggest that a complete merging process is as follows: the vortices deform first due to the mutually induced straining; the deformation results in elliptical vortices and an angle between the major axis of each elliptical vortex and the line joining the two vortices, which in turn cause an attraction of fluid particles from one vortex to the other; sheetlike vortex structures are thus formed; and finally the velocity field induced by these sheetlike structures readily pushes two vortex cores together. This study suggests that the competition between the self-induced rotation and mutual attraction of vortices governs the formation of the sheetlike structures, and consequently the merger. When the flow is viscous, the separation between vortices reduces and the mutual attraction increases with time by diffusion. As the mutual attraction dominates over the self-induced rotation, sheetlike structures are formed gradually and merger eventually occurs. The onset time of merger is thus found to depend not only on the initial separation but also on the Reynolds number. The former determines when the mutual attraction will become dominant and the latter controls the speed at which sheetlike structures grow.
Cylindrical nebulons, symbolic computation and Bäcklund transformation for the cosmic dust acoustic waves
Authors: Tian Bo , Gao Yi-Tian
Published: June 2005

In a cosmic dusty plasma, the dust-acoustic-wave propagation may be described by a cylindrical Kadomtsev-Petviashvili equation. In this Letter, for such modeling of environments like supernova shells, Saturn’s F-ring, etc., cylindrical nebulons and an auto-Bäcklund transformation are presented via symbolic computation. Nebulon structures are discussed, and possibly observable effects are proposed for cosmic plasmas.
A relativistic beam-plasma system with electromagnetic waves
Authors: Evstatiev E. G. , Morrison P. J. , Horton W.
Published: June 2005

A nonlinear multiwave model that describes the interaction of an electron beam, plasma waves, and electromagnetic waves in a cold plasma is derived and studied. The derivation, which is based on slow amplitude and phase change approximations, begins with the electromagnetic Lagrangian coupled to an electron beam, a background plasma, and electrostatic and electromagnetic waves. The model obtained is finite dimensional, and allows for efficient computational and analytical study. Numerical computations demonstrate that with the inclusion of an electromagnetic wave with the plasma wave, the beam-plasma instability is suppressed. If two electromagnetic waves that satisfy a beat-wave matching condition are included, the plasma wave is seen to be amplified provided the beat-wave amplitude exceeds a certain threshold.
Velocity profiles, stresses, and Bagnold scaling of sheared granular system in zero gravity
Authors: Baran Oleh , Kondic Lou
Published: June 2005

We report the results of three-dimensional event-driven simulations of sheared granular system in a Couette geometry. The simulations use realistic boundary conditions that may be expected in physical experiments. For a range of boundary properties we report velocity and density profiles, as well as forces on the boundaries. In particular, we find that the results for the velocity profiles throughout the shearing cell depend strongly on the interaction of the system particles with the physical boundaries. Even frictional boundaries can allow for significant slippage of the particles, therefore reducing the shear in the system. Next, we present stress distributions both for controlled volume and for controlled stress configurations. We discuss the dependence of solid volume fraction on shear rate under the constant-pressure condition, and Bagnold scaling in volume-controlled simulations. In addition, we study the influence of oscillatory driving of one of the domain boundaries on the system properties.
Narrowing of the frequency-linewidth in structured magnetic strips: Experiment and theory
Authors: Kuanr Bijoy , Camley R. E. , Celinski Z.
Published: June 2005

We examine the frequency-linewidth in structured magnetic materials experimentally and theoretically and show that this linewidth can decrease as the external field (or the frequency) is increased. This decrease in the frequency-linewidth occurs in many different systems and does not indicate an increase in damping at low frequencies, as has been suggested. Further, the frequency-linewidth can be very large for extended ferromagnetic films, but becomes significantly smaller for structured films that are narrower than a few microns.
Thermal stability of hafnium–silicate and plasma-nitrided hafnium silicate films studied by Fourier transform infrared spectroscopy
Authors: Quevedo-Lopez M. A. , Chambers J. J. , Visokay M. R. , Shanware A. , Colombo L.
Published: June 2005

Structure and bonding changes in ultrathin hafnium–silicate (HfSiO) and plasma-nitrided HfSiO (HfSiON) films as a result of thermal annealing are presented. To track these changes, attenuated total reflection Fourier transform infrared spectroscopy (FTIR) and high-resolution transmission electron microscopy were used. It is shown that for films with a given Si content, HfSiON films have superior thermal stability compared to the corresponding HfSiO films. It is also demonstrated that besides giving chemical state changes for the thin-film constituents, FTIR can also be used to track interfacial SiO2 growth as well as phase separation in ultrathin high-κ films resulting from thermal annealing.
Role of near-surface states in ohmic-Schottky conversion of Au contacts to ZnO
Authors: Mosbacker H. L. , Strzhemechny Y. M. , White B. D. , Smith P. E. , Look D. C. , Reynolds D. C. , Litton C. W. , Brillson L. J.
Published: June 2005

A conversion from ohmic to rectifying behavior is observed for Au contacts on atomically ordered polar ZnO surfaces following remote, room-temperature oxygen plasma treatment. This transition is accompanied by reduction of the “green” deep level cathodoluminescence emission, suppression of the hydrogen donor-bound exciton photoluminescence and a ∼0.75eV increase in n-type band bending observed via x-ray photoemission. These results demonstrate that the contact type conversion involves more than one mechanism, specifically, removal of the adsorbate-induced accumulation layer plus lowered tunneling due to reduction of near-surface donor density and defect-assisted hopping transport.
Patterning of hydrogenated microcrystalline silicon growth by magnetic field
Authors: Fejfar A. , Stuchlík J. , Mates T. , Ledinský M. , Honda S. , Kočka J.
Published: June 2005

A way of influencing growth of silicon films by magnetic field is demonstrated. Permanent magnet(s) placed under the substrate influenced the discharge in a mixture of silane and hydrogen and led to formation of microcrystalline regions in otherwise amorphous film. The pattern of microcrystalline regions varied with the orientation of the magnetic field. Microscopic study by atomic force microscopy and by micro-Raman spectroscopy revealed that the microcrystalline regions resulted from a higher density of crystalline grain nuclei, increased at the locations where the magnetron effect could be expected. This phenomenon could be used to study the transition between amorphous and microcrystalline growth. Moreover, we suggest it as a kind of “magnetic lithography” for the preparation of predefined microcrystalline patterns in otherwise amorphous silicon films.
Microfluidic gating of an organic electrochemical transistor
Authors: Mabeck Jeffrey T. , DeFranco John A. , Bernards Daniel A. , Malliaras George G. , Hocdé Sandrine , Chase Christopher J.
Published: June 2005

A microfluidic-based organic electrochemical transistor is reported. The integrated microfluidic channel not only confines and directs the flow of liquid electrolyte over the active layer of the transistor but also provides the gate electrode for the transistor. The active layer employed in this work is poly(3, 4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), which results in a transistor that is inherently “on” but that can be turned “off” through application of a positive gate voltage. The transistor behavior is understood in terms of an electrochemical mechanism and is shown to depend on the ionic strength of the electrolyte. The applicability of the device to microfluidic-based chemical and biological sensing is discussed.
Cardiac glycosides inhibit TNF-α/NF-κB signaling by blocking recruitment of TNF receptor-associated death domain to the TNF receptor
Authors: Yang Qingfeng , Huang Wei , Jozwik Catherine , Lin Yong , Glasman Mirta , Caohuy Hung , Srivastava Meera , Esposito Dominic , Gillette William , Hartley James , Pollard Harvey B.
Published: June 2005

Digitoxin and structurally related cardiac glycoside drugs potently block activation of the TNF-α/NF-κB signaling pathway. We have hypothesized that the mechanism might be discovered by searching systematically for selective inhibitory action through the entire pathway. We report that the common action of these drugs is to block the TNF-α-dependent binding of TNF receptor 1 to TNF receptor-associated death domain. This drug action can be observed with native cells, such as HeLa, and reconstituted systems prepared in HEK293 cells. All other antiinflammatory effects of digitoxin on NF-κB and c-Jun N-terminal kinase pathways appear to follow from the blockade of this initial upstream signaling event.
Adenovirus E4orf6 targets pp32/LANP to control the fate of ARE-containing mRNAs by perturbing the CRM1-dependent mechanism
Authors: Higashino Fumihiro , Aoyagi Mariko , Takahashi Akiko , Ishino Masaho , Taoka Masato , Isobe Toshiaki , Kobayashi Masanobu , Totsuka Yasunori , Kohgo Takao , Shindoh Masanobu
Published: June 2005

E4orf6 plays an important role in the transportation of cellular and viral mRNAs and is known as an oncogene product of adenovirus. Here, we show that E4orf6 interacts with pp32/leucine-rich acidic nuclear protein (LANP). E4orf6 exports pp32/LANP from the nucleus to the cytoplasm with its binding partner, HuR, which binds to an AU-rich element (ARE) present within many protooncogene and cytokine mRNAs. We found that ARE-mRNAs, such as c-fos, c-myc, and cyclooxygenase-2, were also exported to and stabilized in the cytoplasm of E4orf6-expressing cells. The oncodomain of E4orf6 was necessary for both binding to pp32/LANP and effect for ARE-mRNA. C-fos mRNA was exported together with E4orf6, E1B-55kD, pp32/LANP, and HuR proteins. Moreover, inhibition of the CRM1-dependent export pathway failed to block the export of ARE-mRNAs mediated by E4orf6. Thus, E4orf6 interacts with pp32/LANP to modulate the fate of ARE-mRNAs by altering the CRM1-dependent export pathway.
Loss of C/EBPα cell cycle control increases myeloid progenitor proliferation and transforms the neutrophil granulocyte lineage
Authors: Porse Bo T. , Bryder David , Theilgaard-Mönch Kim , Hasemann Marie S. , Anderson Kristina , Damgaard Inge , Jacobsen Sten Eirik W. , Nerlov Claus
Published: June 2005

CCAAT/enhancer binding protein (C/EBP)α is a myeloid-specific transcription factor that couples lineage commitment to terminal differentiation and cell cycle arrest, and is found mutated in 9% of patients who have acute myeloid leukemia (AML). We previously showed that mutations which dissociate the ability of C/EBPα to block cell cycle progression through E2F inhibition from its function as a transcriptional activator impair the in vivo development of the neutrophil granulocyte and adipose lineages. We now show that such mutations increase the capacity of bone marrow (BM) myeloid progenitors to proliferate, and predispose mice to a granulocytic myeloproliferative disorder and transformation of the myeloid compartment of the BM. Both of these phenotypes were transplantable into lethally irradiated recipients. BM transformation was characterized by a block in granulocyte differentiation, accumulation of myeloblasts and promyelocytes, and expansion of myeloid progenitor populations—all characteristics of AML. Circulating myeloblasts and hepatic leukocyte infiltration were observed, but thrombocytopenia, anemia, and elevated leukocyte count—normally associated with AML—were absent. These results show that disrupting the cell cycle regulatory function of C/EBPα is sufficient to initiate AML-like transformation of the granulocytic lineage, but only partially the peripheral pathology of AML.
The multiple signals assessed by female satin bowerbirds: could they be used to narrow down females' choices of mates?
Authors: Robson Timothy E , Goldizen Anne W , Green David J
Published: June 2005

Female choice based on multiple male traits has been documented in many species but the functions of such multiple traits are still under debate. The satin bowerbird has a polygynous mating system in which males attract females to bowers for mating; females choose mates based on multiple aspects of males and their bowers. In this paper, we demonstrate that females use some cues to decide which males to examine closely and other cues to decide which males to mate with. Female visitation rates to bowers were significantly related to male size and the males' ‘solitary’ display rates, and, to a lesser extent, to the numbers of bower decorations. After controlling for female visitation rates, it was found that a male's mating success was significantly related to his size and the rate at which he ‘painted’ his bower with saliva and chewed up plant material.
Terminal reproductive effort in a marsupial
Authors: Isaac Joanne L , Johnson Christopher N
Published: June 2005

Life-history theory predicts that as organisms approach the end of their life, they should increase their reproductive effort (RE). However, studies on mammals often find that measures of RE do not vary with maternal age. This might be because offspring have some control over energy transfer which may constrain adaptive variation in RE by mothers, particularly in eutherian mammals where placental function is primarily controlled by offspring. However, in marsupials, energy transfer is primarily by lactation and under maternal control, leaving marsupial mothers free to vary RE. Here, we provide the first analysis, to our knowledge, of age-specific RE in a marsupial, the common brushtail possum. RE, measured as the proportion of maternal mass lost during lactation, was strongly correlated with offspring mass as a yearling. Older females had higher RE, gave birth earlier in the season and were more likely to produce two offspring in a year. Females with high RE in one year were lighter at the beginning of the next breeding season. These results provide the clearest support yet for terminal RE in a mammal.
Modulation of passive force in single skeletal muscle fibres
Authors: Rassier Dilson E , Lee Eun-Jeong , Herzog Walter
Published: June 2005

In this study, we investigated the effects of activation and stretch on the passive force–sarcomere length relationship in skeletal muscle. Single fibres from the lumbrical muscle of frogs were placed at varying sarcomere lengths on the descending limb of the force–sarcomere length relationship, and tetanic contractions, active stretches and passive stretches (amplitudes ofca10% of fibre length at a speed of 40% fibre length/s) were performed. The passive forces following stretch of an activated fibre were higher than the forces measured after isometric contractions or after stretches of a passive fibre at the corresponding sarcomere length. This effect was more pronounced at increased sarcomere lengths, and the passive force–sarcomere length relationship following active stretch was shifted upwards on the force axis compared with the corresponding relationship obtained following isometric contractions or passive stretches. These results provide strong evidence for an increase in passive force that is mediated by a length-dependent combination of stretch and activation, while activation or stretch alone does not produce this effect. Based on these results and recently published findings of the effects of Ca2+on titin stiffness, we propose that the observed increase in passive force is caused by the molecular spring titin.
Compositional convection in the presence of a magnetic field. II. Cartesian plume
Authors: Eltayeb I.A , Hamza E.A , Jervase J.A , Krishnan E.V , Loper D.E
Published: June 2005

The analysis of part I, dealing with the morphological instability of a single interface in a fluid of infinite extent, is extended to the case of a Cartesian plume of compositionally buoyant fluid, of thickness 2
x
0
, enclosed between two vertical interfaces. The problem depends on six dimensionless parameters: the Prandtl number,
σ
; the magnetic Prandtl number,
σ
m
; the Chandrasekhar number,
Q
c
; the Reynolds number,
Re
; the ratio,
B
v
, of vertical to horizontal components of the ambient magnetic field and the dimensionless plume thickness. Attention is focused on the preferred mode of instability, which occurs in the limit
Re
≪1 for all values of the parameters. This mode can be either
sinuous
or
varicose
with the wavenumber vector either
vertical
or
oblique
, comprising four types. The regions of preference of these four modes are represented in regime diagrams in the (
x
0
, 
σ
) plane for different values of
σ
m
,
Q
c
,
B
v
. These regions are strongly dependent on the field inclination and field strength and, to a lesser extent, on magnetic diffusion. The overall maximum growth rate for any prescribed set of the parameters
σ
m
,
Q
c
,
B
v
, occurs when 1.3<
x
0
<1.7, and is sinuous for small
σ
and varicose for large
σ
. The magnetic field can enhance instability for a certain range of thickness of the plume. The enhancement of instability is due to the interaction of the field with viscous diffusion resulting in a reverse role for viscosity. The dependence of the helicity and
α
-effect on the parameters is also discussed.
The development of sex differences in digital formula from infancy in the Fels Longitudinal Study
Authors: McIntyre Matthew H , Ellison Peter T , Lieberman Daniel E , Demerath Ellen , Towne Bradford
Published: June 2005

Relative finger lengths, especially the second-to-fourth finger length ratio, have been proposed as useful markers for prenatal testosterone action. This claim partly depends on an association of relative finger lengths in adults with related sex differences in children and infants. This paper reports the results of a study using serial radiographs to test for both sex differences in the fingers of infants and children and for a relationship between sex differences in the children and infant finger and adult finger length ratios. This is the first study using long-term serial data to evaluate the validity of finger length ratios as markers. We found not only that sex differences in finger length ratios arise prior to puberty, but that sex differences in the fingers of children are highly correlated with adult finger length ratios. Our results strongly encourage the further use of finger length ratios as markers of perinatal testosterone action.
Sensory, computational and cognitive components of human colour constancy
Authors: Smithson H.E
Published: June 2005

When the illumination on a scene changes, so do the visual signals elicited by that scene. In spite of these changes, the objects within a scene tend to remain constant in their apparent colour. We start this review by discussing the psychophysical procedures that have been used to quantify colour constancy. The transformation imposed on the visual signals by a change in illumination dictates what the visual system must ‘undo’ to achieve constancy. The problem is mathematically underdetermined, and can be solved only by exploiting regularities of the visual world. The last decade has seen a substantial increase in our knowledge of such regularities as technical advances have made it possible to make empirical measurements of large numbers of environmental scenes and illuminants. This review provides a taxonomy of models of human colour constancy based first on the assumptions they make about how the inverse transformation might be simplified, and second, on how the parameters of the inverse transformation might be set by elements of a complex scene. Candidate algorithms for human colour constancy are represented graphically and pictorially, and the availability and utility of an accurate estimate of the illuminant is discussed. Throughout this review, we consider both the information that is, in principle, available and empirical assessments of what information the visual system actually uses. In the final section we discuss where in our visual systems these computations might be implemented.
Radio frequency identification and food retailing in the UK
Authors: Jones Peter , Clarke‐Hill Colin , Comfort Daphne , Hillier David , Shears Peter
Published: June 2005

Purpose

This paper aims to offer an outline of the characteristics of radio frequency identification (RFID) technology and briefly discusses some of its perceived benefits and challenges for food retailers in the UK.

Design/methodology/approach

The paper draws material largely from trade and practitioner sources and illustrates general themes with specific retail examples.

Findings

The paper suggests that RFID has the potential to offer food retailers a wide range of benefits throughout the supply chain including tighter management and control of the supply chain, reductions in shrinkage, reduced labour costs and improved customer service while also facilitating compliance with traceability protocols and food safety regulations. At the same time food retailers will need to address a number operational and strategic challenges and consumer privacy concerns before they can fully realise these benefits.

Originality/value

This paper provides a brief and accessible outline of the RFID developments in food retailing which will interest non‐specialists working in and in association with this sector of the retail marketplace.
Implementing value‐transparency in supply relations
Authors: Lamming Richard , Zhang Jian , Caldwell Nigel , Phillips Wendy
Published: June 2005

Purpose

To explore and identify the strategic approaches firms may follow in their pursuit of value transparency (VT) in inter‐organisational relations in supply networks.

Design/methodology/approach

Through the use of game theory an understanding of the difficulties of co‐operation and information transfer is developed. Game theory and marginal analysis facilitate an advanced application of VT.

Findings

While the article acknowledges the limitations of prescriptive precision in strategy matters, it is not proposed that firms would follow any single part of the outlined strategies. However, through rational analysis of the strategic options presented it may be possible to foresee potential negative outcomes, and through structuring undesirable scenarios managers may be able to reduce the risk of their occurrence.

Practical implications

A model is proposed that aids firms in the selection of supply partners for VT and VT modes. Recognising that certain conditions will be more likely to support a more rapid and extensive adoption of VT, the paper identifies the role that aspects of organisations' economic environments may play.

Originality/value

The article acknowledges the limitations of modelling and game theory‐based approaches but suggests that through considering the interests and benefits of the other party, practical insights may be developed and the likely outcomes of various scenarios considered.