bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bridging domain methods for coupled atomistic–continuum models with L2 or H1 couplings
Authors: Guidault P.‐A. , Belytschko T. 
Published: September 2008

AbstractA bridging domain method for coupled atomistic–continuum models is proposed that enables to compare various coupling terms. The approach does not require the finite element mesh to match the lattice spacing of the atomic model. It is based on an overlapping domain decomposition method that makes use of Lagrange multipliers and weight functions in the coupling zone in order to distribute the energy between the two competing models. Two couplings are investigated. The L2 coupling enforces the continuity of displacements between the two models directly. The H1 coupling involves the definition of a strain measure. For this purpose, a moving least‐square interpolant of the atomic displacement is defined. The choice of the weight functions is studied. Patch tests and a graphene sheet with a crack are studied. It is shown that both continuous and discontinuous weight functions can be used with the H1 coupling whereas the L2 coupling requires continuous weight functions. For the examples developed herein, the L2 coupling produces less error in the zone of interest. The flexibility of the H1 coupling with constant weight function may be beneficial but the results may be affected depending on the topology of the bridging zone. Copyright © 2008 John Wiley & Sons, Ltd.
Comparison study for numerical solution and travelling wave solution for Ito coupled system
Authors: Kawala A.M. 
Published: September 2008

AbstractIn this article, the classical fourth‐order Runge Kutta method and Heun's method are applied to initial value problems for system of ordinary differential equations in nonlinear cases, which we reach it by painaleve analysis, focusing our interest on special case which leads to Travelling wave solution of Ito coupled nonlinear partial differential system. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009
Scapular stress fracture: a palaeopathological case consistent with crutch use
Authors: Darton Y. 
Published: September 2008

AbstractThis report describes a defect on the right scapula of a 50 to 60 year old male slave who had been buried extra‐muros in the Le Colombier cemetery of Vaison‐la‐Romaine (5th to 6th century AD) in Vaucluse, France. This injury can only be described as a stress fracture, most likely associated with heavy and persistent use of the humerus in abduction. Other bony defects on the skeleton included early signs of ossification of the glenohumeral joint, slight vertebral discopathy, and osteoarthrosis on the right hip. A relationship between scapular stress fractures and walking devices has been described in the current medical literature, and taking this in consideration, possible aetiologies for this scapular defect include either consistent use of a crutch or routine physical labour. Little information is available on either stress fractures or assisted walking devices in antiquity; therefore this information is a valuable contribution to palaeopathology. Copyright © 2008 John Wiley & Sons, Ltd.
Some types of vertebral pathologies in the Argar Culture (Bronze Age, SE Spain)
Authors: Jiménez‐Brobeil S. A. , Oumaoui I. Al , Souich Ph. du 
Published: September 2008

AbstractA collection of 1825 vertebrae belonging to 105 individuals from several Argaric Culture sites (Bronze Age, SE of Spain) were studied. Several pathologies that could provide information about activity patterns were analysed, including spondylolysis, compression fractures and Schmorl's nodes. Spondylolysis appears exclusively in men. Compression fractures seem to be more related to age (osteoporosis) and are more frequent in women, but without statistical significance. Schmorl's nodes affect a large number of the individuals studied, with a slight predominance in men; there are no differences by age. The results obtained were compared with the available archaeological and anthropological information, which shows a clear division of activities by sex in the Argaric population. The validity of studying these pathologies as activity patterns is discussed. Copyright © 2008 John Wiley & Sons, Ltd.
Two‐component “Onionlike” micelles with a PPO core, a PDMAEMA shell and a PEO corona: formation and crosslinking
Authors: Petrov Petar , Tsvetanov Christo B , Jérôme Robert 
Published: September 2008

AbstractBACKGROUND: Chemical or physical crosslinking of supramolecular assemblies gives them stability in a wide range of environments. Much attention is paid to multilayer (onion‐like) polymeric micelles because their functionality is higher than classic core‐shell micelles. This work reports on the formation and crosslinking of onion‐like micelles prepared by mixing two different block copolymers containing a crosslinkable poly(dimethylaminoethyl methacrylate) (PDMAEMA) block.RESULTS: Block copolymers of a crosslinkable PDMAEMA block were synthesized by atom transfer radical polymerization of 2‐(dimethylamino)ethyl methacrylate (DMAEMA) from poly(propylene oxide) (PPO) or poly(ethylene oxide) (PEO) macroinitiators. The (PDMAEMA13)‐block‐PPO69‐block‐(PDMAEMA13) triblock formed wormlike core‐shell micelles, which were converted into ellipsoidal onion‐like micelles on mixing with the PEO45‐block‐P(DMAEMA8‐co‐MMA4) diblock. Onion‐like micelles were crosslinked by quaternization of DMAEMA units.CONCLUSION: Formation of onion‐like micelles by mixing two different AB (ABA) and B′C block copolymers and their subsequent crosslinking is a valuable approach towards stabilized supramolecular assemblies of a higher complexity and functionality than the individual constitutive components. Copyright © 2008 Society of Chemical Industry
Synthesis, characterization and cleavage of linear polymers attached to silica nanoparticles formed using thiol‐acrylate conjugate addition reactions
Authors: Khire Vaibhav S. , Kloxin April M. , Couch Charles L. , Anseth Kristi S. , Bowman Christopher N. 
Published: September 2008

AbstractThis study investigates the formation of linear polymer grafts using thiol‐acrylate conjugate addition reactions on nanoparticle surfaces. Silica nanoparticles were first modified with an amine functionality, followed by the attachment of a photocleavable acrylate. Dithiol‐diacrylate films were attached to the particles through the surface acrylate groups at various stoichiometric ratios of thiol to acrylate by conducting amine‐catalyzed conjugate addition polymerizations. The particles were then exposed to UV light to release the grafted polymer by photocleavage. The cleaved, grafted polymers were analyzed using infrared spectroscopy and gel permeation chromatography and compared to polymers formed in the bulk, which remained unattached to the particles. The measured number and weight average molecular weights were similar for both polymer types within experimental error and increased from 2000 to 5000 g/mol and 4000 to 10,000 g/mol, respectively, as the ratio of limiting to excess functionality increased from 0.8 to 1. Both number and weight average molecular weights followed the trend of step growth polymers with the highest molecular weight achieved for stoichiometric monomeric mixtures. Surface coverage of the nanoparticles was estimated using the molecular weight and thermogravimetric data and was found to be uniform (∼0.15 chains/nm2) irrespective of the stoichiometry of the reacting monomers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6896–6906, 2008
Heterograft copolymers via double click reactions using one‐pot technique
Authors: Dag Aydan , Durmaz Hakan , Demir Emrah , Hizal Gurkan , Tunca Umit 
Published: September 2008

AbstractThe double click reactions (Cu catalyzed Huisgen and Diels–Alder reactions) were used as a new strategy for the preparation of well‐defined heterograft copolymers in one‐pot technique. The synthetic strategy to the various stages of this work is outlined: (i) preparing random copolymers of styrene (St) and p‐chloromethylstyrene (CMS) (which is a functionalizable monomer) via nitroxide mediated radical polymerization (NMP); (ii) attachment of anthracene functionality to the preformed copolymer by the o‐etherification procedure and then conversion of the remaining CH2Cl into azide functionality; (iii) by using double click reactions in one‐pot technique, maleimide end‐functionalized poly(methyl methacrylate) (PMMA‐MI) via atom transfer radical polymerization (ATRP) of MMA and alkyne end‐functionalized poly (ethylene glycol) (PEG‐alkyne) were introduced onto the copolymer bearing pendant anthryl and azide moieties. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6969–6977, 2008
Age‐specific expression of resistance to a neonicotinoid insecticide in the whitefly Bemisia tabaci
Authors: Nauen Ralf , Bielza Pablo , Denholm Ian , Gorman Kevin 
Published: September 2008

AbstractNeonicotinoid insecticides retain a crucial role within many chemical and integrated control strategies for the tobacco whitefly, Bemisia tabaci Gennadius, in spite of the establishment of potent and widespread resistance in many areas. Metabolic resistance mechanisms mediated by overexpression of P450‐dependent monooxygenases have been implicated in neonicotinoid resistance in the two most prevalent B. tabaci biotypes. Further characterisation of resistance to the neonicotinoid imidacloprid in populations of both these B‐ and Q‐types is reported.Expression of resistance to imidacloprid was age specific in B‐ and Q‐type strains of B. tabaci. The highest observed resistance ratio at LC50 expressed in prepupal nymphs was 13, compared with at least 580 in their adult counterparts. For all strains, resistance expressed in immatures was not sufficiently potent to compromise recommended imidacloprid application rates.Targeting neonicotinoids towards immature life stages of B. tabaci may circumvent the protection conferred by current mechanisms of resistance, simultaneously reducing the selection pressures imposed. However, such tactics may enhance the expression of existing resistance mechanisms in immatures, or promote the establishment of novel ones expressed in all life stages. Copyright © 2008 Society of Chemical Industry
Determination of critical points on silicon nanofilms: surface and quantum confinement effects
Authors: Lioudakis Emmanouil , Othonos Andreas , Nassiopoulou A. G. 
Published: September 2008

AbstractIn this work, we present a comprehensive study of the optical properties of nanocrystalline silicon films with thickness varied from 5 to 30 nm. Spectroscopic ellipsometry is employed to determine the dielectric functions of these films using a structural two‐layer model based on the rigorous Airy formula. Our investigation gives an important insight of the origin of critical points for direct and indirect gaps of nanocrystalline silicon films as well as the evolution of them with decreasing the film thickness. The influence of the quantum confinement effect due to the nanoscale grain size and the surface vibrations at the interface on the optical properties are examined in detail. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Semi‐analytical modelling of short channel effects in Si double gate, tri‐gate and gate all‐around MOSFETs
Authors: Tsormpatzoglou A. , Dimitriadis C. A. , Clerc R. , Pananakakis G. , Ghibaudo G. 
Published: September 2008

AbstractAn analytical expression for the three‐dimensional potential distribution along the channel of short channel silicon multi‐gate MOSFETs is described in weak inversion. The analytical solutions cover three different cases of multi‐gate devices: Symmetrical double gate (DG), tri‐gate (TG) and gate‐all‐around (GAA) MOSFETs. Using the three‐dimensional potential distribution in the silicon film, the subthreshold drain current is calculated from which the threshold voltage and the subthreshold swing were extracted. The threshold voltage roll‐off, the subthreshold swing and the drain‐induced barrier lowering of the multi‐gate devices are compared, showing the critical advantage of GAA structures concerning the short channel effects. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Physics based capacitance modeling of short‐channel double‐gate MOSFETs
Authors: Børli H. , Vinkenes K. , Fjeldly T. A. 
Published: September 2008

AbstractA precise compact 2D capacitance model for nanoscale DG MOSFETs in all operating regions is presented. The modeling of the sub‐threshold capacitances is based on the conformal mapping technique, where the corners of the device are treated specifically. In moderate to strong inversion, we obtain self‐consistent results based on the 2D Poisson's equation. The results are in excellent agreement with numerical simulations. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of two‐dimensional periodic arrays of metallodielectric nanosandwiches
Authors: Papanikolaou N. , Gantzounis G. , Stefanou N. 
Published: September 2008

AbstractWe report a theoretical study of two‐dimensional periodic arrays of composite particles, consisting of two metallic nanodisks separated by a dielectric spacer, using an efficient and accurate multiple‐scattering method, which was originally developed for systems of spherical particles and recently extended to non‐spherical shapes. In particular, we discuss the plasmonic excitations in such isolated nanosandwiches and study the influence of geometrical parameters like the thickness of the dielectric spacer. Moreover, we investigate the interaction between such composite particles as they approach each other in a two‐dimensional periodic lattice. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Atomic‐scale configuration of catalyst particles on GaN nanowires
Authors: Kehagias Th. , Komninou Ph. , Dimitrakopulos G. P. , Chèze C. , Geelhaar L. , Riechert H. , Karakostas Th. 
Published: September 2008

AbstractWell‐aligned single crystalline GaN nanowires were grown on Al2O3 (0001) by molecular beam epitaxy. An initial 0.3 nm thick Ni layer was employed as catalyst. Atomic‐scale electron microscopy observations revealed the epitaxial growth and the crystal quality of the GaN nanowires with basal stacking faults being the only structural defect. Single crystalline droplets on the tip of the nanowires were identified as a Ni‐based cubic oxide with a 0.208 nm {100} lattice spacing and were oriented along [001]/[0001], (010)/(1$ \bar 1 $00) with respect to GaN. Crystal fitting of the two mismatched lattices is realized by a dense network of misfit dislocations at the interface, so that the oxide lattice is relaxed close to its strain‐free value. Analytical methods revealed the positions of the misfit dislocation cores, showing a curved and slightly rough oxide/GaN interface. The observations are consistent with the vapour‐liquid‐solid growth mechanism. Controlled radial growth and thickening of the nanowires was achieved by varying the growth regime. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electronic structure investigation of nickel phthalocyanine thin film interfaces with inorganic and organic substrates
Authors: Petraki Fotini , Kennou Stella 
Published: September 2008

AbstractThe interfacial electronic properties of ultra thin films of Nickel Phthalocyanine (NiPc) on inorganic (polycrystalline Au and Ag, sputtered‐ITO) as well as organic (PEDOT:PSS) substrates were compared. The formation of the interfaces was studied by X‐ray and Ultra‐Violet Photoelectron Spectroscopies (XPS, UPS). From the experimental results, information about the interfacial chemistry, band bending in the organic semiconductor and interfacial dipoles was deduced. The valence band structure, the HOMO position and the work function of the NiPc were also determined. The hole injection barrier at the interface was obtained for all substrates and the energy band diagrams were traced in all cases. A Fermi level alignment was found in the interfaces with inorganic substrates, whereas a pinning of the Fermi level was observed with the organic substrate resulting in a significant decrease of the hole injection barrier. All systems investigated divert from the Schottky‐Mott rule and the observed interfacial dipoles appear to increase as the work function value of the substrate increases. The present study shows the importance of the chemical character of the substrate in the electronic properties of the interfaces with an organic semiconductor. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modified MIS‐structure based on nanoporous silicon with enhanced sensitivity to the hydrogen containing gases
Authors: Gorbanyuk T. , Evtukh A. , Litovchenko V. , Solntsev V. 
Published: September 2008

AbstractThe gas sensitivity of metal‐insulator‐semiconductor (MIS)‐structures based on nanoporous silicon with active electrodes from palladium/tungsten oxide composite has been studied. It was found that the using of palladium/tungsten oxide composite (instead of thin palladium film) leads to enhanced sensitivity of MIS structures to hydrogen sulphide in air. The mechanism of this phenomenon has been established. The enhanced H2S sensitivity is explaind in the following way. The microparticles of tungsten trioxide inside palladium matrix stimulate the dissociation of hydrogen sulphide molecules, and hydrogen atoms and/or protons flow down to palladium surface, are absorbed by palladium volume, diffuse to palladium/oxidized nanoporous silicon interface. Hydrogen atoms adsorbed at the interface are polarized and give rise to a dipole layer. As a result, the voltage shift of the capacity‐voltage (C‐V) curve proportional to the measured gas concentration is observed. The surface microstructure of Pd/WO3 composite was studied by AFM microscopy. The chemical content of the composite film has been investigated by SIMS. It was found that the composite film on nanoporous silicon surface poses the holes with the size about 0.05 μm, the mean separation between tungsten oxide microparticles is 1‐2 μm. It also was found that the using of the additional double layer polymer film (polymer film (phthalocyanine zinc)/semicon‐ductor film (cadmium sulphide)) on composite film surface leads to the additional enhancement of the gas sensitivity to hydrogen sulphide. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of two analog buffers implemented with low‐temperature polysilicon thin‐film transistors for active matrix displays applications
Authors: Pappas Ilias , Siskos Stilianos , Ghibaudo Gerard , Dimitriadis Charalambos A. 
Published: September 2008

AbstractIn this paper a comparison in the performance of two analog buffers for Active Matrix Displays (AMDs) applications is presented. The two buffers are implemented by using low‐temperature polysilicon thin‐film transistors (LT poly‐Si TFTs) presenting high immunity to the threshold voltage variations of the TFTs devices. The verification of their functionality and performance was made through simulation with Synopsys HSpice. In order the simulations to be realistic and the performance as close to reality as possible, parameters extraction was made from fabricated LT poly‐Si TFTs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A comparative evaluation of de‐embedding methods for on‐wafer RF CMOS inductor S‐parameter measurements
Authors: Drakaki M. , Hatzopoulos A. , Siskos S. 
Published: September 2008

AbstractThe impact of existing de‐embedding methods applied on on‐wafer RF s‐parameter measurements to evaluate the characteristics of CMOS integrated inductors is examined. Probe pad and metal interconnect line associated parasitic elements need to be removed (de‐embedded) from on‐wafer measurements of inductors fabricated on silicon substrates for proper evaluation of inductor characteristics, such as inductance, quality factor and resonance frequency. For this purpose a chip was fabricated in 0.5 μm CMOS TM1P twin‐tub AMIS technology (Figure 1), with octagonal and spiral inductors and various types of dummy structures, such as different types of open, and short structures as well as a thru structure. The dummy structures are necessary in order to extract the parasitic element components. The Device‐under‐Test (DUT) was a 3.5 turn octagonal inductor of line width 12 μm, spacing 2 μm and external diameter of 160 μm. Existing de‐embedding methods include the open‐short de‐embedding method, a three‐step de‐embedding method, a pads‐short‐open (psod), and a modified four‐step de‐embedding method. These methods have been tested mostly for small devices such as MOS transistors. The impact of each de‐embedding method on inductor characteristics extraction is evaluated and results show differences in the order of 36% for the value of peak quality factor and a maximum difference of 9% for the resonance frequency. The comparative evaluation of the existing de‐embedding methods is based on results extracted from measured S‐parameter data for measurements up to 20 GHz, as well as on results obtained by using the HFSS EM simulator. Based on the results, the modified four‐step method is the most accurate method, and a discussion of improvements to further increase the accuracy of the de‐embedding is done, for a precise characterization of the DUT. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A real time fingerprint identification system based on the AFS8600 sensor and the C6713 DSP processor
Authors: Tselios K. , Zois E. N. , Livanos N. A. , Nassiopoulos A. 
Published: September 2008

AbstractIn this paper, a fingerprint pre‐process and identification algorithm is implemented using the TMS320C6713 DSP starter kit (DSK) module, along with the Authentec AFS 8600 fingerprint sensor. Database: Acquisition is performed using a solid state sensor. The sensor postulates emerge from the theory of the Electric Field technology. Method: Images are first subjected to a frequency and orientation processing. This is achieved using Gabor‐based filters. This processing has been optimized and implemented on the DSP system. A new method has been developed in order to extract the feature vector of the fingerprint image. A grid, centered at the corepoint of the image, is applied to the fingerprint image in order to derive local information. Classification algorithms are developed, which include training as well as evaluating phase. The types of classifiers used were based on the Bayesian approach along with the K‐nearest neighbour. Results: An identification accuracy of 90% was achieved which is comparable to other procedures described in the literature. Conclusion: The combination of a fingerprint processing and identification algorithm using a low cost sensor and DSP module has been presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)