bluuebunny/crossref_metadata_2025 huggingface dataset:
Temporal control of subduction magmatism in the eastern Trans‐Mexican Volcanic Belt: Mantle sources, slab contributions, and crustal contamination
Authors: Gómez‐Tuena Arturo , LaGatta Alexandra B. , Langmuir Charles H. , Goldstein Steven L. , Ortega‐Gutiérrez Fernando , Carrasco‐Núñez Gerardo
Published: August 2003

The magmatic record of the easternmost part of the Trans‐Mexican Volcanic Belt elucidates how temporal changes in subduction parameters influence convergent margin volcanism. In the Palma Sola massif, three phases of magmatic rocks with distinct chemical characteristics were emplaced in a relatively short time span (∼17 Ma): Miocene calc‐alkaline plutons, latest Miocene‐Pleistocene alkaline plateau basalts, and Quaternary calc‐alkaline cinder cones. Plutons have arc‐like trace element patterns (Ba/Nb = 16–101), and their Sr, Nd, and Pb isotopic compositions become more “depleted” with increasing SiO2contents. Their Pb isotopes are bracketed by the subducted sediments and Pacific mid‐ocean ridge basalts (MORB), requiring the participation of an unradiogenic component that mixes with a sediment contribution. High Sr/Y and Gd/Yb ratios in the least radiogenic pluton might indicate a melt coming from the subducted MORB. Trace element patterns of the plateau basalts show moderate or negligible subduction contributions (Ba/Nb = 6–31). Rocks without subduction signatures are similar to ocean island basalts, indicating melting of an enriched mantle wedge. The plateau basalts form an array in206Pb/204Pb‐207Pb/204Pb space that trends toward the composition of the subducted sediment. The sediment component is also indicated by the inverse correlations between Pb isotopes and subduction signals. This component has high Th/Nd coupled with low143Nd/144Nd, but lower Pb/Nd and Sr/Nd ratios than the bulk sediment. These suggest melting of a sediment that has lost fluid mobile elements prior to melting. The Quaternary cinder cones have moderate subduction signals (Ba/Nb = 16–41), and their isotopic compositions correlate with differentiation indices. Contamination with the local Paleozoic basement can explain the petrogenesis of the youngest rock suite. The geochemical differences among the suites indicate temporal modifications in the chemical characteristics of the slab input. These variations can be associated with modifications in the Pacific subduction regime. We suggest the Miocene magmatic phase was formed by an essentially flat subduction angle that favored melting of the subducted oceanic crust. Slab rollback in the Pliocene allowed melting of deeper portions of the wedge by the injection of dehydrated sediment melts. In the Quaternary, an even steeper subduction angle provided negligible slab contributions to the Palma Sola region, and upper crustal contamination largely controls the petrogenesis.
A large silent earthquake in the Guerrero seismic gap, Mexico
Authors: Kostoglodov Vladimir , Singh Shri Krishna , Santiago Jose Antonio , Franco Sara Ivonne , Larson Kristine M. , Lowry Anthony R. , Bilham Roger
Published: August 2003

Geodetic measurements from a network of permanent GPS stations along the Pacific coast of Mexico reveal a large “silent earthquake” along the segment of the Cocos‐North American plate interface identified as the Guerrero seismic gap. The event began in October of 2001 and lasted for 6–7 months. Average slip of ∼10 cm produced measurable displacements over an area of ∼550 × 250 km2. The equivalent moment magnitude of the event was Mw ∼ 7.5. Recognition of this and previous slow event here indicate that the seismogenic portion of the plate interface is not loading steadily, as hitherto believed, but is rather partitioning the stress buildup with episodic, as opposed to steady‐state or periodic, slip downdip of the seismogenic zone. This process increases the stress at the base of the seismogenic zone, bringing it closer to failure. These results call for a reassessment of the seismic potential of Guerrero and other seismic gaps in Mexico.
Seasonal variation of cloud particle size as derived from AVHRR remote sensing
Authors: Kawamoto Kazuaki , Nakajima Teruyuki
Published: August 2003

We have analyzed long‐term NOAA/AVHRR (Advanced Very High Resolution Radiometer) global data from 1985 to 1994 to investigate the variation of the cloud particle size for low‐lying water clouds. Here we focus on seasonal change of the cloud particle size instead of studying the variability the absolute values, since there are several critical factors which affect the long time‐series thus obtained, such as calibration uncertainty, sensor degradation, change of satellite platform, orbital shift and so on. Amazon and East Asia cases will be shown in addition to global average. All the cases show decreasing trend with signals of significant seasonal cycles (particularly local cases such as Amazon and East Asia). The inter‐annual decreasing trend and a gap in 1989 would be artifacts caused from above reasons. Seasonal cycles, however, would be explained by the seasonal change in precipitation that is able to control the amount of aerosol and cloud particles, though we need to be careful to propose such a direct relationship between them, since water clouds do not cover all the precipitating clouds.
Evaluation of CHAMP radio occultation refractivity using data assimilation office analyses and radiosondes
Authors: Poli P. , Ao C. O. , de la Torre Juárez M. , Joiner J. , Hajj G. A. , Hoff R. M.
Published: August 2003

The radio occultation experiment on the CHAMP satellite has been collecting observations of the Earth's atmosphere since April 2001. Previous work has shown that diffraction effects not accounted for by geometrical optics processing can be partially corrected by back‐propagation and canonical transform methods, such as implemented at the Jet Propulsion Laboratory. In the present paper we evaluate the bias and standard deviation of refractivity differences between Data Assimilation Office global analyses and observations processed by these three methods. In the tropics at 2–5 km altitude, the refractivity biases range between −2.5% and −0.5% for geometrical optics, between −1% and 0.5% for back‐propagation, and between −0.5% and 1.5% for canonical transform. We also assess the methods by performing one‐dimensional variational temperature retrievals and comparing them with close radiosondes. Our final conclusion is that canonical transform is a better candidate than geometrical optics and back‐propagation for generating GPS radio occultation datasets for data assimilation.
A cloud‐free, satellite‐derived, sea surface temperature analysis for the West Florida Shelf
Authors: He Ruoying , Weisberg Robert H. , Zhang Haiying , Muller‐Karger Frank E. , Helber Robert W.
Published: August 2003

Clouds are problematic in using Advanced Very High Resolution Radiometer (AVHRR) imagery for describing sea surface temperature (SST). The Tropical Rainfall Measuring Mission Microwave Imager (TMI) observes SST through clouds, providing daily, 1/4° maps under all weather conditions excepting rain. A TMI limitation, however, is coarse resolution. Optimal interpolation (OI) is used to generate a cloud‐free, 5‐km, daily SST analysis for the West Florida Shelf (WFS) by merging the high‐resolution (cloud‐covered) AVHRR with the coarse‐resolution (cloud‐free) TMI SST products. Comparisons with in‐situ data show good agreements. Given large spatial gradients by coastal ocean processes, this regional analysis has advantage over the global, weekly, 1° Reynolds SST. A 5‐year (1998–2002) OI SST analysis is diagnosed using Empirical Orthogonal Functions. The first two modes represent annual cycles, one by surface heat flux and another by shelf circulation dynamics.
Preface to special section on enhanced Subarctic influence in the California Current, 2002
Authors: Huyer Adriana
Published: August 2003

This special section discusses a rare phenomenon: strong enhancement of Subarctic influence in the California Current system in the summer of 2002. This cold, fresh anomaly in the upper halocline was more extreme than any prior observation, though historical records extend back for several decades. The Subarctic anomaly extended more than 1500 km along the U. S. west coast, from 49°N to 33°N. It brought high‐nutrient waters into the coastal upwelling zone off Oregon and northern California, and produced exceptionally high chlorophyll concentrations. Inner shelf oxygen concentrations were very high near the surface and very low near the bottom. The presence of this Subarctic water mass was associated with anomalous southward currents detected by three different methods: by satellite‐tracked drifters, a mid‐shelf mooring, and by satellite altimetry. Large‐scale wind forcing over the northeastern Pacific during the previous winter and spring seems to be responsible for these anomalies.
Comparing continental and oceanic cloud susceptibilities to aerosols
Authors: Lohmann Ulrike , Lesins Glen
Published: August 2003

A common practice in remote sensing studies of the aerosol indirect effect is to consider the correlation between the droplet effective radius and the aerosol index. However, this correlation is not unique as the relationship depends also on the liquid water path. Moreover, it differs for oceanic and continental clouds because clouds over land generally have higher cloud bases, are thinner and have a higher average cloud droplet number concentration for a given aerosol index than marine clouds. Only when using aerosol number concentration at cloud base instead of aerosol index and using an effective radius representative for the whole cloud rather than just at cloud top, do the defined susceptibilities of oceanic and continental clouds obtained from ECHAM4 climate model simulations agree within the standard errors. This has important consequences for properly interpreting the magnitude of the anthropogenic indirect aerosol effect on climate.
Weighted averages of magnetization from magnetic field measurements: A fast interpretation tool
Authors: Fedi Maurizio
Published: August 2003

Magnetic anomalies may be interpreted in terms of weighted averages of magnetization (WAM) by a simple transformation. The WAM transformation consists of dividing at each measurement point the experimental magnetic field by a normalizing field, computed from a source volume with a homogeneous unit‐magnetization. The transformation yields a straightforward link among source and field position vectors. A main WAM outcome is that sources at different depths appear well discriminated. Due to the symmetry of the problem, the higher the considered field altitude, the deeper the sources outlined by the transformation. This is shown for single and multi‐source synthetic cases as well as for real data. We analyze the real case of Mt. Vulture volcano (Southern Italy), where the related anomaly strongly interferes with that from deep intrusive sources. The volcanic edifice is well identified. The deep source is estimated at about 9 km depth, in agreement with other results.
Production, structure, and optical properties of ZnO nanocrystals embedded in CaF2 matrix
Authors: Liu Y. C. , Xu H. Y. , Mu R. , Henderson D. O. , Lu Y. M. , Zhang J. Y. , Shen D. Z. , Fan X. W. , White C. W.
Published: August 2003

High-quality ZnO nanocrystals have been fabricated by zinc ion implantation (160 keV, 1×1017 ions/cm2) into a CaF2(111) single-crystal substrate followed by thermal annealing from 300 to 700 °C. X-ray diffraction results show that ZnO nanocrystals in CaF2(111) substrate have a (002) preferred orientation. The average grain size is ranging from 14 to 19 nm corresponding to the annealing temperatures from 500 to 700 °C. A very strong ultraviolet near-band edge emission is observed from 372 to 379 nm. The emission intensity is enhanced and linewidth is narrowed as the annealing temperature increases. The commonly observed visible green emission associated with deep-level defects in ZnO is suppressed.
In-plane resonant cavities with photonic crystal boundaries etched in InP-based heterostructure
Authors: Mulot M. , Qiu M. , Swillo M. , Jaskorzynska B. , Anand S. , Talneau A.
Published: August 2003

The optical properties of in-plane cavities with photonic crystal boundaries fabricated into an InP/GaInAsP/InP slab waveguide structure are presented. The investigated cavities are realized as segments of different lengths bounded by V-shaped double or single mirrors in straight photonic crystal waveguides and were designed to have resonance in the 1.55 μm wavelength range. High aspect ratio etching of the photonic crystal is achieved using Ar/Cl2-based chemically assisted ion beam etching. The optical loss inside the photonic crystal waveguide was determined by fitting the measured transmission spectra with two-dimensional finite-difference time-domain simulations. The experimental results, combined with the simulations, indicate that major sources of loss in these cavities are radiation through the cavity mirrors and out-of-plane scattering of the third-order mode inside of the cavity. The best results were obtained for a 6.2 μm long resonant cavity with double mirrors that had an appreciably high-quality factor of 460.
Influence of electron–electron interactions on supercurrent in SNS structures
Authors: Engström K. , Kinaret J. , Shekhter R. I. , Puska M. , Saarikoski H.
Published: August 2003

A superconductor–normal quantum dot–superconductor structure where the number of electrons in the dot can be controlled by a gate voltage is considered. The effect of electron–electron interactions on the supercurrent between the two superconductors is studied. Using an analytic model and numerical density functional calculations it is found that Coulomb interactions can make the system quantum-mechanically more “rigid,” i.e. increase its sensitivity to phase gradients, thereby enhancing the supercurrent through the structure, especially for small phase differences. Accordingly, it is found that the supercurrent in this structure can be controlled by the gate voltage.
Influence of electron–electron scattering on spin-polarized current states in magnetically wrapped nanowires
Authors: Gurzhi R. N. , Kalinenko A. N. , Kopeliovich A. I. , Yanovsky A. V. , Bogachek E. N. , Landman Uzi
Published: August 2003

The role of electron–electron collisions in the formation of spin-polarized current states in a spin guide—a system consisting of a nonmagnetic conducting channel wrapped in a grounded nanoscale magnetic shell—is studied. It is shown that under certain conditions the spin guide can generate and transport nonequilibrium electron density with high spin polarization over long distances even though frequent electron–electron scattering causes drifting of the nonequilibrium electrons as a whole. Ways to convert the spin-polarized electron density into a spin-polarized electric current are proposed.
Anomalous temperature dependence of coercivity in precipitation hardened Pr–Co–Cu–Ti magnets
Authors: Zhang Jian , Liu Hui , Rong Chuan-bin , Zhang Hong-wei , Zhang Shao-ying , Shen Bao-gen , Bai Yuan-qiang , Li Bao-he
Published: August 2003

The anomalous temperature dependence of coercicity, Hc(T), has been observed in precipitation hardened PrCo6.7−xCuxTi0.3 (x=0.2–1) magnets. Transmission electron microscopy reveals that they exhibit a cellular microstructure. With an increase of Cu content, the Curie temperature of the 2:17 phase remains nearly unchanged whereas that of the 1:5 phase decreases. The peak of Hc(T) becomes higher, broader and shifts towards low temperature while the room temperature coercivity remains low and does not change with an increase of Cu content. There is a strong correlation between the Curie temperature of the 1:5 phase and the peak of Hc(T). The effect of Cu on Hc(T) cannot be explained by a traditional domain wall pinning model. It is highly likely that their magnetization reversal is controlled by the nucleation of reverse domains in isolated 2:17 cells.
Formation of vanadium-based ohmic contacts to n-GaN
Authors: Song June O , Kim Sang-Ho , Kwak Joon Seop , Seong Tae-Yeon
Published: August 2003

We investigate vanadium (V)-based ohmic contacts on n-GaN (Nd=2.0×1018 cm−3) as a function of annealing temperature. It is shown that the V (60 nm) contacts become ohmic with specific contact resistances of 10−3–10−4 Ω cm2 upon annealing at 650 and 850 °C. The V (20 nm)/Ti (60 nm)/Au (20 nm) contacts produce very low specific contact resistances of 2.2×10−5 and 4.0×10−6 Ω cm2 when annealed at 650 and 850 °C, respectively. A comparison shows that the use of the overlayers (Ti/Au) is very effective in improving ohmic property. Based on Auger electron spectroscopy and glancing-angle x-ray diffraction results, possible explanations for the annealing temperature dependence of the ohmic behavior of the V-based contacts are described and discussed.
Effect of Kerr nonlinearity on defect lasing modes in weakly disordered photonic crystals
Authors: Liu B. , Yamilov A. , Cao H.
Published: August 2003

We studied the effect of Kerr nonlinearity on lasing in defect modes of weakly disordered photonic crystals. Our time-independent calculation based on self-consistent nonlinear transfer matrix method shows that Kerr nonlinearity modifies both frequencies and quality factors of defect modes. We also used a time-dependent algorithm to investigate the dynamic nonlinear effect. Under continuous pumping, the spatial sizes and intensities of defect lasing modes are changed by Kerr nonlinearity. Such changes are sensitive to the nonlinear response time.
Doping of the nanocrystalline semiconductor zinc oxide with the donor indium
Authors: Agne Th. , Guan Z. , Li X. M. , Wolf H. , Wichert Th. , Natter H. , Hempelmann R.
Published: August 2003

Doping of the nanocrystalline semiconductor ZnO with the donor In111 was achieved by the incorporation of In111 atoms during the growth process followed by a hydrothermal treatment at 473 K. The incorporation of In111 on substitutional Zn sites was shown by the perturbed γγ angular correlation technique. The structural quality of nanocrystalline ZnO with a mean grain size of 11 nm is significantly improved by annealing at 473 K, as revealed by x-ray diffraction, transmission electron microscopy, optical absorption measurements, and photoluminescence spectroscopy. It is shown that the incorporation of In111 on undisturbed Zn sites in nanocrystalline ZnO seems to be supported by the onset of crystal growth and by the removal of intrinsic defects.
Spectral narrowing in a perylene dye
Authors: Dharmadhikari A. K. , Thakur M. , Wang L. , Cammarata V.
Published: August 2003

Spectral narrowing has been observed in the solution of a recently synthesized perylene dye for pumping by the second harmonic of a picosecond Nd:yttrium–aluminum–garnet laser. The threshold energy for spectral narrowing at a concentration of 2×10−3 M was observed to be 1.8 μJ for an excitation area of 5 mm2. Spectrally narrowed emission with a linewidth of 5 nm centered at 600 nm was observed without incorporating any mirrors. The maximum photoluminescence quantum efficiency was 23% while the conversion efficiency in the laserlike emission was found to be 20%. A combination of stimulated and cooperative emission with a dominant contribution of the stimulated emission is attributed to the observed line narrowing and laserlike emission.
Visualization of individual carbon nanotubes with fluorescence microscopy using conventional fluorophores
Authors: Prakash Rohit , Washburn S. , Superfine Richard , Cheney Richard E. , Falvo Michael R.
Published: August 2003

We demonstrate that individual carbon nanotubes (CNTs) can be visualized with fluorescence microscopy through noncovalent labeling with conventional fluorophores. Reversal of contrast in fluorescence imaging of the CNTs was observed when performing labeling procedure in a nonpolar solvent. Our results are consistent with a CNT-fluorophore affinity mediated by hydrophobic interaction. The reverse-contrast images also provide clear indication of nanotube location.
Quantum mechanical predictions of nonscalar equations of state and nonmonotonic elastic stress-strain relations
Authors: Swift Damian C. , Ackland Graeme J.
Published: August 2003

In continuum mechanics, the isotropic part of the stress deviator (mean pressure) is routinely assumed to depend on the isotropic part of the strain deviator (compression). This assumption was tested using ab initio quantum mechanical calculations of elastic stress as a function of elastic strain and compression. Except for face-centered-cubic elements, the mean pressure varied significantly with shear strain as well as compression. In general, the shear stress did not increase monotonically with elastic shear strain. These phenomena may be important when comparing experimental data obtained on different time scales, particularly when interpreting dynamic response data from short-pulse laser experiments.
Second-harmonic generation in periodically poled GaN
Authors: Chowdhury Aref , Ng Hock M. , Bhardwaj Manish , Weimann Nils G.
Published: August 2003

We report the experimental demonstration of second-harmonic generation in periodically poled GaN by first-order quasiphase matching. The periodically poled structure was grown by plasma-assisted molecular-beam epitaxy. We observed about 9 μW of second-harmonic power from a fundamental input laser wavelength of 1658.6 nm with a normalized conversion efficiency of 12.76% W−1 cm−2. The ability to perform nonlinear wavelength conversion by periodic poling and the fact that GaN has a very wide window of transparency, pave the way for GaN to be used for nonlinear optical devices in telecommunications as well as a nonlinear light source for biochemical detection in the far infrared and deep ultraviolet.
Self-pulsation in InGaN laser diodes with saturable absorber layers
Authors: Ohno T. , Ito S. , Kawakami T. , Taneya M.
Published: August 2003

Self-pulsating InGaN laser diodes with a p-type InGaN saturable absorber (SA) layer are demonstrated. The SA layer consists of a 1-nm-thick p-type InGaN well surrounded by 2-nm-thick p-type In0.02Ga0.98N barriers. The lower barrier of the SA is located on the 18-nm-thick p-type Al0.3Ga0.7N evaporation-prevention layer of the active region. Self-pulsation is demonstrated for output powers in the range 4 to 22 mW with corresponding self-pulsation frequencies in the range 1.6 to 2.9 GHz. Results indicate that the position of the SA layer in the structure has a strong influence on the carrier lifetime and is responsible for the observation of self-pulsation in these devices.
Specific heat capacity and hemispherical total emissivity of liquid Si measured in electrostatic levitation
Authors: Sung Y. S. , Takeya H. , Hirata K. , Togano K.
Published: August 2003

Containerless solidification of Si was carried out via electrostatic levitation. Typical undercooling up to 370 K, which is 0.22 of its melting temperature, was obtained. A t(T) function in a time–temperature profile was analytically determined from radiative cooling curves measured during containerless solidification. With the analytical t(T) function, the ratio of constant pressure specific heat capacity to hemispherical total emissivity cP(T)/εT(T) was estimated. cP(T) and εT(T) were further derived to describe the temperature-dependent cooling behavior of liquid Si during containerless solidification in electrostatic levitation, which can be expressed as cPdrv(T)=3R+4.8×10−4⋅T+4.157×105⋅T−2−1.002×10−7⋅T2 (J/mol K) and εTdrv(T)=0.267−5.615×10−5⋅T+9.133×10−9⋅T2, respectively.
Isoelectronic doping of AlGaN alloys with As and estimates of AlGaN/GaN band offsets
Authors: Foxon C. T. , Novikov S. V. , Zhao L. X. , Harrison I.
Published: August 2003

The isoelectronic doping of AlxGa1−xN alloys with arsenic in films grown by molecular-beam epitaxy has been investigated. In photoluminescence spectra of AlxGa1−xN layers, with an increase in Al mole faction, there is a progressive shift of the position of the blue band emission towards higher energies. The observed energy shift for blue band emission is less than the corresponding increase in the band gap of AlxGa1−xN. A model is presented, which can explain the observed shift in the energy of the blue band emission. This model also allows the AlxGa1−xN/GaN valence band offset to be estimated.
Size determination of nanoparticles in low-pressure plasma with laser-induced incandescence technique
Authors: Eom G. S. , Park C. W. , Shin Y. H. , Chung K. H. , Park S. , Choe W. , Hahn J. W.
Published: August 2003

We derive analytic formulas describing the temporal behavior of the laser-induced incandescence (LII) signal in both case of the heat transfer governed by radiation and collision. Using these formulas, we can describe the temporal behavior of the LII signal and determine the dimension of nanosize particles in low-pressure plasma. Simple calibration procedure is introduced for quantitative measurement of the particle size with the LII technique.
Infusing metal into self-organized semiconductor nanostructures
Authors: Kohno Hideo , Takeda Seiji
Published: August 2003

We show that more complex nanoheterostructures can be formed readily by using templates through a self-organized process. We fabricated silicon/silicide/oxide-heterostructured nanowires by infusing metal into chains of crystalline-silicon nanospheres. The structure and composition were studied using transmission-electron-microscopy-based approaches.
Chirality effect of single-wall carbon nanotubes on field emission
Authors: Liang Shi-Dong , Xu N. S.
Published: August 2003

The chirality effect of an opened-end single-wall carbon nanotube on field emission is studied by using the tunneling theory with the tight-binding approximation. The characteristic of the emission-current line density versus field is found to be dependence on the chirality of nanotubes. A metallic tube has a line density higher than that of a semiconducting one. Also, for semiconducting tubes, a tube of larger chiral angle has a line density higher than that of smaller chiral angle; a zigzag semiconducting tube has a smallest line density among the others. Further, the Fowler–Nordheim plots may have a nonlinear behavior in high current region. Finally, at temperature T<1000 K, the emission current is almost independent of temperature. Our results are explained by the energy band structure of nanotubes.
Dynamic formation of ring-shaped patterns of colloidal particles in microfluidic systems
Authors: Lim David S. W. , Shelby J. Patrick , Kuo Jason S. , Chiu Daniel T.
Published: August 2003

This letter reports the formation of patterns of micrometer-sized beads within the steady-state recirculation flow of a microvortex generated in a microfluidic system. The mechanism by which these patterns form relies on a delicate balance between the centrifugal and displacement forces experienced by the recirculating particles with a lift force exerted on the particles near the solid boundary of the microcavity. Our observation was made possible by the small dimensions of the microchannels we used and by the presence of steep velocity gradients unique to microfluidic devices.
Combinatorial libraries of semiconductor gas sensors as inorganic electronic noses
Authors: Aronova M. A. , Chang K. S. , Takeuchi I. , Jabs H. , Westerheim D. , Gonzalez-Martin A. , Kim J. , Lewis B.
Published: August 2003

We have fabricated thin-film combinatorial gas sensor libraries based on doped semiconducting SnO2 thin films. Combinatorial pulsed-laser ablation was used to deposit compositionally varying arrays of sensor elements onto a prepatterned device electrode configuration. Using multiplexing electronics, we have demonstrated the detection of chloroform, formaldehyde, and benzene gases at concentrations down to 12.5 ppm through pattern recognition of signals from the arrays of sensors. This technique of fabricating gas sensor arrays as combinatorial libraries can be applied to the manufacturing of portable electronic noses.
Polarization dynamics over broad time and field domains in modified ferroelectrics
Authors: Jullian Christelle , Li J. F. , Viehland D.
Published: August 2003

The dynamics of polarization switching have been investigated over extremely broad time (10−8<t<102 s) and field ranges for various modified Pb-based perovskite ferroelectrics. The results unambiguously demonstrate the presence of extremely broad relaxation time distributions for switching, which can extend over decade(s) in orders of magnitude in time.
Improvements in near-field optical performance using localized surface plasmon excitation by a scatterer-formed aperture
Authors: Tanaka Kenji , Hosaka Hiroshi , Itao Kiyoshi , Oumi Manabu , Niwa Takashi , Miyatani Tatsuya , Mitsuoka Yasuyuki , Nakajima Kunio , Ohkubo Toshifumi
Published: August 2003

Near-field optical performance is greatly improved using our proposed near-field structure, in which a metal scatterer formed in an aperture enhances localized surface plasmon (LSP) excitation and functions as an alternative near-field light source. Based on the design through a finite-difference time-domain method, the scatterer-formed aperture is fabricated with an electron beam technique, and its near-field optical distribution is observed using a scanning near-field optical microscope. The scatterer-formed aperture enhances the near-field optical energy due to LSP excitation, thereby realizing a significant and simultaneous improvement in throughput and spatial resolution.
Hydrogenation of Zr60Ti2Cu20Al10Ni8 bulk metallic glass
Authors: Mattern Norbert , Gebert Annett
Published: August 2003

The influence of hydrogen on the short-range order of Zr60Ti2Cu20Al10Ni8 bulk metallic glass has been investigated. Interstitial solution of hydrogen up to a hydrogen-to-metal ratio of H/M=0.43 was reached in 1 mm thick bulk samples by slow electrochemical charging. Preferred occupation of interstitial sites of polyhedra formed by Zr atoms is observed. The atomic distances of higher coordination shells expand with hydrogen analogously to the macroscopic volume expansion.
III-nitride photonic crystals
Authors: Oder T. N. , Shakya J. , Lin J. Y. , Jiang H. X.
Published: August 2003

We report the achievement of nanofabrication and characterization of a triangular lattice array of photonic crystals (PCs) with diameter/periodicity as small as 100/180 nm on an InGaN/GaN multiple quantum well using electron-beam lithography and inductively coupled plasma dry etching. Optical measurements of the PCs performed using near-field scanning optical microscopy showed a 60° periodic variation with the angle between the propagation direction of emission light and the PCs lattice. An unprecedented maximum enhancement factor of 20 was obtained for the emission light intensity at wavelengths as short as 475 nm at room temperature with emission light parallel to the Γ–K direction of the PCs lattice. The implications of these results to nitride-based optoelectronic devices, particularly in improving the light extraction efficiency in light-emitting diodes both for blue/green as well as UV emitters, are discussed.
Effect of dye doping on the charge carrier balance in PPV light emitting diodes as measured by admittance spectroscopy
Authors: Hulea I. N. , van der Scheer R. F. J. , Brom H. B. , Langeveld-Voss Bea M. W. , van Dijken A. , Brunner K.
Published: August 2003

Dye doping is a promising way to increase the spectral purity of polymer light-emitting diodes (LEDs). Here we analyze the frequency and field dependence of the complex admittance of Al–Ba–PPV–poly(3,4-ethylenedioxythiophene:polystyrene sulphonic acid)–indium tin oxide LEDs with and without dye. We compare the charge carrier mobilities of pristine and dye-doped double-carrier and hole-only (Au replacing Al–Ba) devices. Dye doping is shown to significantly influence the electron mobilities while the hole mobilities are left unchanged and thereby changing the carrier balance in a double carrier device towards that of a hole only device. The minimum in the LED capacitance as a function of voltage appears to be an excellent probe for the electron trapping phenomenon underlying the reduction of the mobility.
Kinematic synthesis of flight control systems for light aircrafts
Authors: Yaman Yavuz , Akman Yunus , Söylemez Eres
Published: August 2003

In this paper, kinematic synthesis of a planar flight control system mechanism has been conducted for a light aircraft designed and built by TAI. To achieve a simple construction, the four‐bar linkages are used in the synthesis. Freudenstein's Method and Bloch's Method are utilized for analytical three and four bar position syntheses respectively. A case study of an elevator flight control system is presented.
The application of an electrochemical technique to determine the porosity of electroless nickel coatings produced in hypophosphite baths
Authors: Singh Raghuvir
Published: August 2003

An electrochemical polarisation technique was employed to measure the porosity of electroless nickel (EN) coating. The technique is based on the change observed in the electrochemical parameters with varying cathode and/or anode area on a bimetallic corroding surface. The nickel coating test samples were obtained from a hypophosphite plating bath in the presence of different complexing agents. This technique was used to estimate the effect of coating thickness on porosity and the influence of addition of different complexing agents to EN baths on porosity. The results suggest that, unlike other conventional methods, the electrochemical, a non‐destructive method, can detect the smallest pore in an EN‐coating and quantify its size in terms of pore area fraction.
Effect of defatted groundnut concentrate on the physico‐chemical and sensory quality of fura
Authors: Ayo J.A. , Olawale O.
Published: August 2003

The pearl millet kernels were sorted, dehulled, wined, grown, sieved (to produce millet flour), mixed with defatted groundnut concentrate (10, 20, … 50 per cent), spiced (2 per cent – ginger, clove and red pepper), conditioned (with water), weighed into 20g pices, molded, steamed for 30 minutes, mashed to a smooth dough, molded back to a ball, coated with maize flour ready for use. The effect of the added groundnut on the physico‐chemical (moisture, protein, fat, ash, carbohydrate) and sensory (flavour, colour, texture) quality were evaluated. There was an increase in the moisture (19.60‐23.90 per cent), protein (12.69‐20.18 per cent), fat (2.27‐2.51 per cent), ash (2.8‐3.18 per cent), but a decrease in the carbohydrate (62.65‐50.23 per cent). Also, there is a decrease in the mean scores of the texture (7.05‐5.45 per cent) but an increase in that of colour (6.50‐7.15 per cent) with an increase in the added groundnut concentrate (0‐50 per cent). The mean score for odour and taste decreased at above the 40 per cent added groundnut concentrate.
Additional effect of electroless plating film (damping capacity improvement)
Authors: Endo Hiroki , Marui Etsuo
Published: August 2003

Electroless plating treatment is one surface modification technique. An added effect due to electroless plating is expected, and the vibration damping capacity of the structures may be improved by this technique. In the present study, the vibration damping capacity of such electroless plated structures is measured experimentally. Damping capacity can be improved regardless of the plated film materials. Improvement efficiency with an electroless plating film with dispersed foreign particles such as SiC ceramics is higher than with a uniform electroless plating film.
European development of lubricants derived from renewable resources
Authors: Lea C.W.
Published: August 2003

Contends that 40 years ago London Bus and other vehicle companies were using castor oil based fluids in their rear axles thereby obtaining major advantages in consumption of fuel owing to the excellently low coefficient of friction. Investigates a few specific applications drawn from across Europe and other parts of the globe where harvestable resourced lubricants have moved into well established usage.
A wider view of knowledge
Authors: Hannabuss Stuart
Published: August 2003

Argues that current discussion about knowledge management begs the question as to what “knowledge” actually is. Suggests that definitions are usually based upon assumptions about rationality and objectivity, making knowledge propositional and its epistemology non‐intuitive. Highlights the way in which ends‐means and duty‐based factors help to shape knowledge and give it a strong ethical dimension. Argues that traditional managerial paradigms benefit from a wider interpretation of knowledge, as one where greater attention to how it is, as well as what it is, matter to people in organisations. Turns to Asian philosophical views of knowledge, suggesting that knowing and being and acting come closer together in them, and that decision making without such wider epistemological warrants is flawed, above all in environments claiming to exteriorise tacit knowledge into explicit knowledge.
Research is the basis of a collaborative solution for academic libraries: the Victorian Academic Digital Library (VADL)
Authors: O’Connor Steve
Published: August 2003

The CAVAL member libraries believe that the major issue confronting libraries at the start of the new millennium is collection development. These libraries have been committed to the achievement of VADL for the past 12 months. VADL will be a digital library which will be shared and yet reflect the discipline interests of the member universities. VADL has established a range of research into the shape and extent of existing collections within Victoria. This paper highlights the path taken by these libraries, how their response differs from the American experience, and how collaboration is achieved through a new service model.
Putting the pieces together: information literacy at The Open University
Authors: Parker Jo
Published: August 2003

Describes a combined approach to delivering information literacy skills at The Open University Library. Outlines the aims of the newly formed Information Literacy Unit, and identifies three approaches currently used to incorporate information literacy into the curriculum. Focuses on MOSAIC (Making Sense of Information in the Connected Age), an on‐line information literacy course, in particular on issues around assessment, on‐line delivery and support, its use as a staff development tool and positive results of a recent survey. Recommends that information literacy is considered at a strategic level in the higher education sector.
Continuing professional development and workplace learning 3. Sharing skills: a case study in staff development
Authors: King Val
Published: August 2003

Describes an innovative programme designed to learn or improve skills – The Sharing Museum Skills Award – which was later extended to the archives and libraries sector. Funding was made available for the secondment of paid staff or volunteers. Benefits were gained by the secondees, their host organisation and mentors, and the community.
GM selects Fanuc robots for new Vectra bodyshop
Authors: Mortimer John
Published: August 2003

Certain models of the new Vauxhall Vectra passenger car are being manufactured at Ellesmere Port where there is a completely new bodyshop with an installed population of some 660 Fanuc robots.
A high precision robotic docking end effector: the DockbotTM
Authors: Derby Stephen , McFadden John
Published: August 2003

Precision operations, including assembly, need an accurate platform as a base. The described robotic end effector can achieve one micron or smaller repeatability while being relocatable to the required task workspace.
Does your robot really know where it is?
Authors: Schofield Monica
Published: August 2003

Industrial robots are not accurate enough to be used without heavy investment in fixtures and manual programming to correct for positional variations, but this situation could be corrected with the introduction of a new position determination system. PosEye1 allows fixed and mobile robots to determine their absolute position and orientation. The author contends that without more active support from robot manufacturers in adopting such systems, current investment in full off‐line programming systems or digital plant technology will leave the automation industry with a costly “end of cable” problem.
The Acrobot® system for total knee replacement
Authors: Jakopec Matjaz , Harris Simon J. , Rodriguez y Baena Ferdinando , Gomes Paula , Davies Brian L.
Published: August 2003

A “hands‐on” robotic system for total knee replacement (TKR) surgery is presented. Computed tomography (CT) based software is used to accurately plan the procedure pre‐operatively. Intra‐operatively, the surgeon guides a small, special‐purpose robot, called Acrobot®, which is mounted on a gross positioning device. The Acrobot uses active constraint control, which constrains the motion to a pre‐defined region, and thus allows the surgeon to safely cut the knee bones to fit a TKR prosthesis with high precision. A non‐invasive anatomical registration method is used. The system has undergone early clinical trials with very promising outcomes.
A prototype robot for polishing and milling large objects
Authors: Zieliński Cezary , Mianowski Krzysztof , Nazarczuk Kazimierz , Szynkiewicz Wojciech
Published: August 2003

The paper describes a prototype robot which due to its serial‐parallel structure exhibits, high stiffness and has a large work envelope. These features make this robot suitable for relatively high precision machining operations on large workpieces. The conroller for this robot was based on MRROC++, which is a robot programming framework. Thus the controller could be tailored to the tasks at hand, including the capability of in‐program switching of kinematic model parameters. To obtain those parameters for different locations in the work‐space a calibration procedure using linear measurement guides has been devised.
Reflections on the Dühring and Brand cases
Authors: Furedy John J.
Published: August 2003

The concept of “political correctness” (PC) does not have a clear and simple definition on which there is even a majority, let alone universal, consensus. Nevertheless, during the last decade, and especially in North America, a series of events and positions have emerged to which the term PC is at least partially applicable. I shall begin by alluding to North American PC in institutions of higher education and in scientific organizations, which I have discussed elsewhere in more detail. I suggest that North American PC has crossed the Atlantic and elaborate upon this suggestion by discussing the recent dismissal of a tenured member of the teaching staff by Edinburgh University, and relating this case to the Du¨hring dismissal.
Novel automated inspection methods, tools and technologies
Authors: Ranky Paul G.
Published: August 2003

There are many methods and solutions to improve any process, and stay within the established control limits. Statistically analyzed data, received from inspection sensors and other devices, are one of them. Automated inspection sensors and systems are effective tools for controlling variation and obtaining process related knowledge. Automated inspection methods, discussed in this paper, represent an important, nevertheless not the only methods, that lead to process improvement, the ultimate goal of total quality management and control (TQM/TQC). Inspection, as part of the feedback control loop of the overall TQM/TQC process, involves the continual satisfaction of customer requirements at lowest cost by harnessing the efforts of everybody in the company. The key question in any inspection system is as follows: Are the measured values within tolerance, or not, and if they are outside the tolerance limits, why did we produce those parts in the first place?
Modelling strategies for reconfigurable assembly systems
Authors: Yu Jianfeng , Yin Yuehong , Sheng Xinjun , Chen Zhaoneng
Published: August 2003

Knowledge‐based timed colored object‐oriented Petri net (KTCOPN) is presented as a modelling method for a reconfigurable assembly system (RAS) in this paper. Compared to the conventional flexible assembly systems, the configuration of a RAS will allow flexibility not only in assembling a variety of products, but also in changing the system itself. Combining knowledge and object‐oriented methods into timed colored Petri net, allow the characteristic of RAS to be fully expressed. With object‐oriented methods, the whole system can be decomposed into concrete objects explicitly, and their relationship is constructed according to the system assembly requirements. Finally, a simple assembly system modeled by the KTCOPN is given.
Digitised newspapers at Norfolk and Norwich Millennium Library
Authors: Mieczkowska Suzanne , Pryor Kathryn
Published: August 2003

This paper reports a local newspaper digitisation project carried out by the Norfolk Library and Information Service. The project is unique because it is to date the only UK public library project to digitise and index a significant proportion of a newspaper collection. The paper opens with a review of some of the issues in newspaper access and preservation. It then describes how the Norfolk Library and Information Service project was carried out, and offers an assessment of how successfully the project addresses access and preservation issues. The paper concludes that the project should be seen as a success, although the costs involved, and the general unresolved issue of digital preservation means that it is not a practical option for most libraries. Greater information sharing from completed projects is needed, as this will provide a key to future success in other projects.
Academic departmental library collections as curriculum trend indicators
Authors: Swan Philip G.
Published: August 2003

Changes in the Hunter College School of Social Work (HCSSW) Library’s holdings have matched the contemporaneous changes in the field of social work for which it collects. While most schools of social work in the USA, including the program at Hunter, continue to emphasize agency‐based social work practice, the HCSSW Library’s collection indicates that the current curriculum is actually putting more importance on individual psychological problems like depression and eating disorders. This trend toward more private practice psychotherapeutic work has been decried in the field, but the HCSSW Library collection seems to indicate that schools teaching future professionals are complicit in this trend. This, in turn, suggests that an academic library’s collection can often anticipate changes in a field of study before it is widely acknowledged among the faculty who are experts in the field being collected.
The role of materials in advanced sensor technology
Authors: Bogue Robert W.
Published: August 2003

Considers the role of a range of materials being used in advanced sensor technology, including diamond, fullerenes, silicon carbide, superconductors, rare earths and III‐V compounds. Sensors based on these materials are described and their applications discussed.
UK Technology Foresight – sensors strategy for 2015
Authors: McGeehin Peter
Published: August 2003

Summarises the report of a Sensors Task Force which was formed as part of the UK Technology Foresight exercise. Examines the various markets for sensor technology, both globally and in the UK. Details the opportunities and challenges, market pull factors, and the most promising technologies and application areas.
Smart sensors
Authors: Ranky Paul G.
Published: August 2003

The purpose of developing smart (analog and digital) sensors for networked machine/process monitoring, and other tasks, is to make them as easy and trouble free to deploy, program and maintain, as plugging a keyboard, or mouse into a computer. The IEEE 1451 smart transducer interface standards describe a set of open, common, and network‐independent communication interfaces for smart transducers. (“Smartness” here means on‐board data storage/processing capability, interfaced/ integrated with the analog and/or digital sensor.) Several companies and individuals involved in networked control systems of machines, and the measurement and control industries are developing these new standards, in the USA sponsored by the IEEE Instrumentation and Measurement Society’s Technical Committee on Sensor Technology (TC‐9), and the US Department of Commerce NIST Manufacturing Engineering Laboratory.