bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative Study between Wet and Dry Etching of Poly(N‐vinylcarbazole)
Authors: Moreira Taís , Possidonio Shirley , Wang S. Hui , Onmori Roberto K. 
Published: February 2007

AbstractThis work presents the study of two etching techniques, also applied in polymer. The chosen polymer was poly (N‐vinylcarbazole) (PVK), because of its easy processability and custom of process. The polymer was synthesized by “living” free radical polymerization process. Previous studies on the best technique for film preparation had been made. The photolithography process was done, then in sequence the etching process was applied in two separate steps: the wet etching with a polymer solvent and dry etching with argon and oxygen plasma. The comparison of the results shows a significant difference between the etching methods, which will be suitable for films preparation in aiming at novel electronic devices.
Molecular and Supramolecular Dynamics ‐ a Versatile Tool for Self‐Organization of Polymeric Membranes Systems
Authors: Cazacu Adinela , Pasc‐Banu Andreea , Barboiu Mihail 
Published: February 2007

AbstractThe present results show that the self‐organization properties in the membrane phase may provide the first evidence for the possible hybrid transport carrier vs. channel mechanisms in correlation with self‐assembly properties of the heteroditopic receptors. These dynamic self‐organized systems can be tested in liquid membranes, bilayer membranes, mesoporous structures materials or “frozen” in a polymeric hybrid matrix by sol‐gel process, opening the door to the design of a novel class of organic‐inorganic nanomembranes.
Dynamic behavior of PMMA‐PHSA hard spheres suspensions under external electric field
Authors: Giacomelli Fernando Carlos , Pereira Fabiano Vargas , Moussaid Abdellatif , Silveira Nádya Pesce da 
Published: February 2007

AbstractThe dynamic behavior of PMMA‐PHSA hard spheres suspended in distinct organic solvents and under an external electric field with different intensities was evaluated by means of dynamic light scattering (DLS) relaxation rates. The study was carried out using a homebuilt copper capacitor with a black finish mate. The experimental data showed that it is possible to modify considerably the diffusion constant of the PMMA particles when an organic solvent having a relative high dielectric constant is used. The effect was attributed mainly due to an interaction between the external electric field applied with the solvent moieties.
Preparation and Characterization of Resorbable Hydrogel Membranes Useful for Tissue Engineering
Authors: Drumond Walker Soares , Rojas‐Cabrera Walter Israel , Zhao Lili , de Castro Maria Leonora , Laganá Dalva Cruz , Wang Shu Hui 
Published: February 2007

AbstractNew synthetic polymeric membranes of lactic acid were prepared with different chemical composition through copolymerization with ε‐caprolactone and ethylene oxide segments. The prepared copolymers were characterized by hydrogen and carbon‐13 nuclear magnetic resonance (1H‐NMR and 13C‐NMR) and presented wide range of mechanical properties demonstrated by dynamic mechanical thermal analysis (DMA). Porous membranes were prepared by dissolving the polymer in the presence of salts (NaCl or hydroxyapatite) and/or lower mass poly(ethylene glycol) (Mn = 600 or 1,000 g · mol−1). The membranes presented new mechanical and biological characteristics and were suitable for cell penetration, anchorage, differentiation and proliferation. Adherence of cultured fibroblasts on membranes indicates biocompatibility.
Sprayable Polysaccharide‐Based Fiber Reinforced Emulsions for Environmentally Sound Plasticulture
Authors: Malinconico Mario , Santagata Gabriella , Schettini Evelia 
Published: February 2007

AbstractThe increasing demand for mulching and solarization in agriculture is posing serious problems of environmental concerns. Practically all these films are collected by the farmers and left on the ground borders to be incinerated. The same collection by the farmer is difficult; these films being thinner and damaged, their removal through automatic means is almost impossible. The research has focused on an innovative approach where a sort of sprayable water‐based varnish is applied on soil. Such varnish, made of biodegradable polysaccharides mixture, contains biodegradable plasticizers to allow the film to remain elastic for the time needed. Moreover, a set of fibrous natural fillers have been tested, which can be mixed in the varnish or can be preventively applied on soil. The agronomic performances have been measured, together with mechanical properties and degradation behavior. The results seem to confirm the technical feasibility of such approach in developing a sustainable plasticulture.
Erratum: Long‐range JCH heteronuclear coupling constants in cyclopentane derivatives. Part II
Authors: Lacerda Valdemar , da Silva Gil V. J. , Constantino Mauricio G. , Tormena Cláudio F. , Williamson R. Thomas , Marquez Brian L. 
Published: February 2007

AbstractThe original article to which this Erratum refers was published in Magnetic Resonance in volume 45 issue 1.
Safety factor for neuromuscular transmission at type‐identified diaphragm fibers
Authors: Ermilov Leonid G. , Mantilla Carlos B. , Rowley Katharine L. , Sieck Gary C. 
Published: February 2007

AbstractThe safety factor (SF) for neuromuscular transmission varies across limb muscles of different fiber‐type composition. Using intracellular recordings in rat diaphragm fibers, we found that SF varies across muscle fiber types (even within a single muscle), being larger for type IIx or IIb fibers than for type I or IIa fibers. Fiber‐type differences in activation history or mechanical load may contribute to differences in SF and are important determinants of neuromuscular plasticity. Muscle Nerve, 2007
Anomalous quantum‐Hall resistance in bilayer counterflow transport
Authors: Ezawa Z. F. , Suzuki S. , Tsitsishvili G. 
Published: February 2007

AbstractRecent magnetotransport experiments have revealed an anomalous behavior in the quantum Hall (QH) resistance in a bilayer counterflow geometry that it vanishes instead of developing a Hall plateau in the QH regime. This anomalous resistance is explained as a result of the interlayer phase coherence developed spontaneously in the bilayer QH system. We also discuss the mechanism of another anomalous QH resistance discovered in a drag experiment. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Single‐particle state mixing and Coulomb localization in two‐electron realistic coupled quantum dots
Authors: Melnikov Dmitriy V. , Leburton Jean‐Pierre 
Published: February 2007

AbstractThe exchange coupling in a realistic double quantum dot system is computed as a function of the gate confinement and magnetic field using a hybrid multiscale approach where the many‐body Schrödinger equation is solved exactly within the full quantum dot device environment. It is found that at zero magnetic field the exchange energy varies from meV to sub‐μeV value as the confinement gate biases (tunneling barrier) are changed and the system is driven from a single quantum dot to two coupled quantum dots. At the same time the magnetic field of the singlet‐triplet transition is weakly affected by the changes and remains at about 1 T in the same range of the gate biases. The small values of the exchange coupling in this structure are attributed to the large inter‐electron separation arising when the Coulomb repulsion dominates tunneling. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Exciton and biexciton lifetimes in InAs/InP quantum dots emitting at 1.55 µm wavelength under resonant excitation
Authors: Labbé C. , Cornet C. , Folliot H. , Caroff P. , Levallois C. , Rohel T. , Even J. , Gicquel‐Guézo M. , Loualiche S. 
Published: February 2007

AbstractTwo samples of 12 and 72 stacks of InAs/InP quantum dots were grown by molecular beam epitaxy to study the photoluminescence and the dynamical response by a pump‐probe experimental set‐up respectively. The carrier's lifetimes and differential transmission are performed in a function of the excitation density. A comparison of the differential transmission ratio for one quantum dot layer (InAs/InP) and one quantum well (InGaAs/InP) is also investigated. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Resonant tunnelling via two impurity levels in a vertical tunnelling nanostructure
Authors: Mayorov A. S. , Savchenko A. K. , Entin M. V. , Faini G. , Laruelle F. , Bedel E. 
Published: February 2007

AbstractResonant tunnelling through two impurities has been observed in a vertical double‐barrier GaAs/AlGaAs tunnelling diode. It manifests itself as a peak in the I‐V characteristic near the conductance threshold. Analysis of the position of the current peak, its shape and the shift in magnetic field parallel to the current provides information about the characteristics of the two impurities. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Superconductivity of InN caused by In‐In nano‐structure
Authors: Inushima Takashi 
Published: February 2007

AbstractThere is an optimum carrier density for the occurrence of the superconductivity in n‐type InN. The lowest carrier density is limited by the Mott transition of ne ∼ 2 × 1017 cm–3 and the highest density is limited by the superconductivity to metal transition of ne ∼ 5 × 1020 cm–3. Between these carrier densities, InN shows superconductivity and vortex motion is a current tunneling through micro Josephson‐junctions. A mechanism is proposed where the occurrence of the superconductivity is related to the presence of two u ‐parameters of 3/8 and 5/8, which causes In‐In chains of finite length in the ab plane. The In‐In chains, which originate from the In‐In nano‐structure elongating along [11$ \bar 2 $0], are coupled to form micro Josephsonjunctions. A possibility of nano‐structure instability is suggested by the temperature dependence of the u ‐parameter obtained by molecular dynamics calculations. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonlocal dielectric response of an N‐quantum‐well superlattice embedded in bulk and semi‐infinite plasmas in magnetic field
Authors: Horing Norman J. M. , Ayaz Yüksel 
Published: February 2007

AbstractWe derive explicit analytic results for the dynamic, nonlocal and inhomogeneous screening functions of a finite superlattice array of N equally spaced 2D quantum well plasmas embedded in infinite and semiinfinite host bulk‐plasma‐like media. The closed‐form results presented here for the screening functions, which are space‐time matrix inverses of the spatially inhomogeneous dielectric functions, are valid for any number of wells, and can accomodate nonlocality in both the 2D and host plasmas, as well as an ambient normal magnetic field. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A novel quantum laser structure based on InAsN/GaSb system
Authors: Debbichi M. , Ben Fredj A. , Bhouri A. , Saïd M. , Lazzari J.‐L. , Cuminal Y. , Joullié A. , Christol P. 
Published: February 2007

AbstractA new class of dilute‐nitride laser structure to be grown on InAs substrate is simulated for room temperature emission near 3.3 µm. The active region is composed of several strain‐compensated type‐II InAsN/GaSb/InAsN quantum wells having the “W” geometry so as to maximized the electron and hole wavefunctions overlap. Optical gain calculations at 300 K show high material gain values, of the order of 1000 cm–1 with injected carrier density of 1 × 1012 cm–2. Radiative current density inferior to 100 A/cm2 is predicted for room temperature operation. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Self assembly of Eu2O3 nanocrystals and nanoneedles
Authors: Mahajan S. , Redigolo M. , Koktysh D. , Dickerson J. 
Published: February 2007

AbstractThe self‐assembly of europium oxide (Eu2O3) nanocrystals into anisotropic one dimensional europium hydroxychloride (Eu(OH)2Cl) nanostructures is reported. Eu2O3 nanocrystals, synthesized via colloidal chemistry, form one dimensional structures via a stepwise assembly and growth procedure. Transmission electron microscopy (HR‐TEM) reveals the shape and crystal lattice spacing of the nanostructures, whereas X‐ray diffraction (XRD) measurements characterize the nanocrystals' crystallinity. Photoluminescence measurements indicate changes in the site location and environment of the Eu3+ ions. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural and electronic properties of zinc blende BeTe and ist (110) surface
Authors: Baǧcı S. , Duman S. , Tütüncü H. M. , Srivastava G. P. 
Published: February 2007

AbstractStructural and electronic properties of zinc blende BeTe and its (110) surface were investigated using ab initio pseudopotential method based on density‐functional theory and the local‐density approximation (LDA). The calculated electronic structure of bulk BeTe shows very good agreement with experimental results for the top valence bands along the Γ‐X direction. In addition to bulk properties, we have presented structural and electronic properties of BeTe(110) surface. In our calculations, the tilt angle of the top surface layer is found to be 28.8° which is similar to values for other II‐VI(110) surfaces. Finally, the electronic structure for BeTe(110) surface has been presented and discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Donor impurity‐related optical absorption spectra in GaAs‐Ga1–xAlxAs quantum wells: hydrostatic pressure and Γ –X conduction band mixing effects
Authors: Mora‐Ramos M. E. , López S. Y. , Duque C. A. , Velasco V. R. 
Published: February 2007

AbstractUsing a variational procedure within the effective mass approximation, the mixing between the Γ and X conduction band valleys in GaAs‐Ga1–x Alx As quantum wells is investigated by taking into account the effect of applied hydrostatic pressure. Some optical properties such as donor and/or acceptor binding energy and impurity‐related transition energies are calculated and comparisons with available experimental data are presented. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoluminescence spectroscopy and transport electrical measurements reveal the quantized features of Si nanocrystals embedded in an ultra thin SiO2 layer
Authors: Dumas C. , Grisolia J. , Carrada M. , Arbouet A. , Paillard V. , Ben Assayag G. , Bonafos C. , Schamm S. , Claverie A. 
Published: February 2007

AbstractIn this paper, we have investigated the quantized charging features revealed by nanometer scale devices containing a 2D array of Si nanoparticles (nps) embedded into a SiO2 layer. The Si nps were synthesized by ultra low energy ion implantation and annealing under slightly oxidizing ambient. The structural characteristics of the material (oxide thicknesses, nps size and density) have been studied by Transmission Electron Microscopy (TEM) and Energy Filtered TEM (EFTEM). Moreover, photoluminescence (PL) spectroscopy and electrical I(V) measurements using a MOS capacitor addressing only a few nps have been performed at room temperature. It is observed that, as the oxidizing annealing temperature increases, the nps size decreases and the oxide quality is restored. These features appear on the PL spectra as a blue shift of the PL red band linked to quantum confinement into nps and on the I(V) characteristics as an increase of the voltage peak width and a decrease of the main current background. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electronic properties of AB‐stacked nanographite ribbons in an electric field
Authors: Huang Yuan‐Cheng 
Published: February 2007

AbstractIn the presence of transverse (ky‐direction) electric field, the low‐energy electronic properties of the AB‐stacked multilayered nanographite ribbons are studied through the tight‐binding model. The interlayer interactions significantly affect density of states (DOS), energy gap (Eg), band structure. DOS exhibits many special structures, including discontinuities, and divergent peaks. The effective electric field modifies the energy dispersions, alters the subband spacing, produces the new edge state, changes the band gap, and causes the metal‐semiconductor transitions. In the metallic zigzag ribbons, the effect of electric field on band structures is completely reflected in the features of DOS, e.g., the generation of special structures, the shift of peak position, the change of peak height, and the alternation of band gap. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spin dependent Fano effect in an Aharonov‐Bohm interferometer with a magnetic quantum dot
Authors: Seo K. C. , Ihm G. , Lee S. J. 
Published: February 2007

AbstractWe have studied the electron transport of a magnetic quantum structure embedded in an Aharonov‐Bohm (AB) ring. The magnetic structure, which is defined by the spatially inhomogeneous magnetic fields, can be created by ferromagnetic or by superconducting gates. We have found Fano resonances in addition to the background AB oscillations as functions of the electron energy and gate voltage. These resonances can be spin polarized and thus can be used as a spin filter. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Erasable photomemory phenomena in Eu2O3‐, Y2O3‐ and SrTiO3 nanoparticles at room temperature
Authors: Mochizuki Shosuke , Fujishiro Fumito , Mochizuki Teruyuki , Yamamoto Hiroshi 
Published: February 2007

AbstractReversible ultraviolet‐laser‐light‐induced spectral changes have been observed for Eu2O3‐, Y2O3‐ and SrTiO3 nanocrystal specimens at room temperature. Comparing with their bulk specimens, the speed of the changes in the nanoparticle specimens tend to increase. The transitions are explained by photo‐induced reduction and photo‐induced oxidation at nanocrystal surfaces due to exciton instability. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bipolariton laser emission from a GaAs microcavity
Authors: Moreira L. M. , Gonzalez J. C. , Oliveira A. G. , Matinaga F. M. 
Published: February 2007

AbstractBiexciton emission properties were studied in a single GaAs quantum well (QW) semiconductor planar microcavity by photoluminescence measurements at low temperatures. At high pump intensity a bipolariton emission appears close to the lower polariton mode. This new mode appears when we detune the cavity resonance out of the lower polariton branch, showing a laser like behavior. Very small linewidths were measured, lying below 110 µeV and 150 µeV for polariton and bipolariton emission respectively. The input/output power (I/O) measurements show that the bipolariton emission has a weaker coupling efficiency compared to previous results for polariton emission. Varying the pump laser polarization, we were able to show the selection rules for the biexciton particle creation in the quantum well. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Contactless electroreflectance and photoluminescence of InAs quantum dots with GaInNAs barriers grown on GaAs substrate
Authors: Motyka M. , Kudrawiec R. , Misiewicz J. , Pucicki D. , Tlaczala M. , Fischer M. , Marquardt B. , Forchel A. 
Published: February 2007

AbstractInAs quantum dots (QDs) with GaInNAs barriers grown on (001) GaAs substrate by molecular beam epitaxy have been studied by contactless electroreflectance (CER) and photoluminescence (PL) spectroscopies. It has been observed that the overgrowth of self‐organized InAs QDs with GaInNAs layers effectively tunes the QD emission to the 1.3 μm spectral region. In case of PL spectra only one peak related to QD emission has been observed. In the case of CER spectra, in addition to a CER feature corresponding to the QD ground state, a rich spectrum of CER resonances related to optical transitions in InAs/GaInNAs/GaAs QW has been observed. It has been concluded that the application of GaInNAs instead InGaAs leads to better control of emission wavelength from InAs QDs since strains in GaInNAs can be tuned from compressive to tensile. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Elements of nanocrystal high‐field carrier transport modeling
Authors: Sevik C. , Bulutay C. 
Published: February 2007

AbstractEmbedded semiconductor nanocrystals (NCs) within wide bandgap oxide materials are being considered for light emission and solar cell applications. One of the fundamental issues is the high‐field transport in NCs. This requires the combination of a number of tools: ensemble Monte Carlo carrier transport simulation, ab initio band structure of the bulk oxide, Fermi's golden rule modeling of impact ionization and Auger processes and the pseudopotential‐based atomistic description of the confined NC states. These elements are outlined in this brief report. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron correlations in GaAs and AlGaAs superlattices
Authors: Abu Kassim Hasan , Abdul Jalil Ithnin , Yusof Norhasliza , Devi V. R. , Shrivastava Keshav N. 
Published: February 2007

AbstractWe have calculated the electronic correlation energy and the exchange energy of a system of GaAs lattice using the density functional theory. In 15 different calculations, we are able to find the energy values for different number of Al and Ga atoms. We have performed the calculation of the energy of the Schroedinger equation in three different approximations, namely, the local density approximation (LDA), the generalized gradient approximation with exchange (GGA‐X) and the generalized gradient approximation with exchange and correlations (GGA‐XC). The correlation energy has a peak for the cell which has 9 Ga and 5 Al atoms. In this way, we find that the material for which the composition is in the ratio of Ga:Al = 9:5, has the strongest electron correlations. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Chemical bonding of nitrogen in dilute InAsN and high In‐content GaInAsN
Authors: Talwar D. N. 
Published: February 2007

AbstractTo assess the preferential chemical bonding of N in dilute InAsN and high In content GaInNAs alloys we have analyzed the recent infrared absorption and Raman scattering data by using a comprehensive Green's function theory within an 11 parameter rigid‐ion‐model. Our theoretical results provided firm corroboration to some of the observed N‐ related modes to specific bonding (micro clusters) configurations. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoluminescence studies in modulation doped GaInNAs/GaAs multiple quantum wells
Authors: Yilmaz M. , Ulug B. , Ulug A. , Cicek A. , Balkan N. , Sopanen M , Reentilä O. , Mattila M. , Fontaine C. , Arnoult A. 
Published: February 2007

AbstractWe report for the first time the temperature dependent PL spectra from GaInNAs/GaAs triple quantum wells, modulation doped with a 2‐D carrier density of ∼3 × 1011 cm–2 per well. The measurements were carried out at temperatures between 10 and 300 K. The results are analyzed using a Gaussian fitting technique which indicates variable nitrogen composition and/or well‐width fluctuations in the wells. One of the most striking features of the results is the lack of the S‐Shape temperature dependence of the PL peak energy that is commonly observed in undoped dilute nitride quantum wells and is attributed to exciton de‐trapping, which screens the true temperature dependence of the energy gap. Our results compare well with the predictions of the Varshni equation. The temperature dependence of the PL intensity is used to obtain the thermally activated behaviour of the non‐radiative recombination processes that appear to dominate at higher temperatures. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)