bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetic properties of FeCuNbSiB nanocrystallized by flash annealing under high tensile stress
Authors: Herzer Giselher , Budinsky Viktoria , Polak Christian 
Published: June 2011

AbstractWe have investigated the creep induced anisotropy, magnetostriction, domain structure and coercivity of nanocrystalline Fe73.5Cu1Nb3Si15.5B7 crystallized by flash annealing under high tensile stress up to 800 MPa. The samples reveal a magnetic easy plane perpendicular to the stress axis with anisotropy constants up to Ku ≈ 12 kJ/m3 which even exceed the local magneto‐crystalline anisotropy (K1 ≈ 8 kJ/m3) of the crystalline Fe–Si phase. Although coercivity increases with Ku, it remains reasonably small even for huge induced anisotropy constants. The coercivity mechanism can be understood from the interplay of the induced anisotropy and the random fluctuations of the local magneto‐crystalline anisotropy of the crystallites. The tensile stress applied during annealing also affects the saturation magnetostriction constant λs. Thus, λs decreases with increasing magnitude of the annealing stress. This behaviour is compared to the elastic stress dependence of magnetostriction. The latter is well‐known for amorphous Co‐base alloys, but can also be observed in nanocrystalline alloys. The experimental results will be discussed theoretically in terms of the strain dependence of the magnetic anisotropy energy which ultimately provides the physical origin of magnetostrictive phenomena.
The effect of chemical disorder on the magnetic anisotropy of strained Fe–Co films
Authors: Neise C. , Schönecker S. , Richter M. , Koepernik K. , Eschrig H. 
Published: June 2011

AbstractStrained Fe–Co films have recently been demonstrated to exhibit a large magnetocrystalline anisotropy (MCA) and thus to be of potential interest as magnetic storage material. Here, we show by means of density‐functional (DF) calculations, that chemical order can remarkably enhance the MCA. We also investigate the effect of relaxation perpendicular to the applied strain and evaluate the strain energy as a function of Co concentration and substrate lattice parameter. On this basis, favourable preparation routes for films with a large perpendicular anisotropy are suggested.
Effects of Y and Zn atoms on the elastic properties of Mg solid solution from first‐principles calculations
Authors: Yang Fang , Fan Tou‐Wen , Wu Jian , Tang Bi‐Yu , Peng Li‐Ming , Ding Wen‐Jiang 
Published: June 2011

AbstractThe effects of Y and Zn atoms on elastic properties of Mg solid solution are investigated by first‐principles calculations based on density function theory. Five supercell models (Mg96, Mg95Y1, Mg94Y2, Mg95Zn1 and Mg94Zn2) are adopted to simulate the variation of solute atoms content. Structural optimization is performed firstly, and then the five independent elastic constants of Mg solid solution are calculated. The bulk modulus B, shear modulus G, Young's modulus E and Poisson ratio ν are also derived by Voigt–Reuss–Hill (VRH) approximation, indicating a strong dependence of the elastic modulus on concentration of the solute atoms. Using the bulk modulus/shear modulus ratio (B/G), the change in the ductility of Mg solid solution with the solute atom content is further studied. In the end, the electronic density of states (DOS) is calculated and discussed.
Current transport through AlInN/GaN multilayers used as n‐type cladding layers in edge emitting laser diodes
Authors: Charash Ragh , Kim‐Chauveau Hyonju , Vajpeyi Agam , Akther Mahbub , Maaskant Pleun P. , Frayssinet Eric , de Mierry Philippe , Duboz Jean‐Yves , Corbett Brian 
Published: June 2011

AbstractThe current transport properties of an n ‐doped, lattice matched AlInN layer with multiple, periodic GaN insertions are reported. Samples with three and seven insertions were grown and mesa structures were etched through the AlInN structures to different depths to determine the voltage contribution from each heterointerface. The quality of the AlInN surface improved with the GaN insertions and with reducing the thickness of the individual AlInN layers from 80 nm to 55 nm. Simulations suggest that the large conduction band discontinuity can lead to high turn on voltages which can be reduced by high levels of doping. Current‐voltage measurements through the full structure show a diode characteristic which is temperature activated. A quasi‐linear current‐voltage characteristic is measured when the current is driven only through the uppermost GaN interlayer with 80 nm thick AlInN layers, indicating current leakage through defects in these layers (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Drift region optimization in high‐voltage GaN MOS‐gated HEMTs
Authors: Li Zhongda , Chow T. P. 
Published: June 2011

AbstractThe design of AlGaN/GaN heterojunction in high‐voltage lateral GaN MOS‐HEMT was studied and optimized. The effect of the heterojunction on the breakdown voltage of the device was studied using numerical simulations. The effect of the addition of a GaN cap layer on top of the AlGaN/GaN structure was evaluated, showing a higher breakdown voltage as well as a lower oxide field at the gate corner, due to the better Reduced Surface Field (RESURF) effect that originated from the balanced polarization charges. Further a 2‐zone RESURF design was achieved by etching part of the GaN cap in the drift region. The 2‐zone RESURF device showed 33% improvement in breakdown voltage from simulations compared with single zone RESURF devices. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
AlGaN/GaN HFET biosensors working at subthreshold regime for sensitivity enhancement
Authors: Wen Xuejin , Gupta Samit , Nicholson Theodore R. , Lee Stephen C. , Lu Wu 
Published: June 2011

AbstractIn this paper, we report an AlGaN/GaN heterostructure field effect transistor biosensor with enhanced sensitivity at subthreshold regime for streptavidin detection. The AlGaN surface is functionalized by oxidization, silanization, and biotinylation for detection of streptavidin. Using a Pt reference electrode dipped into the buffer as a gate, the device is configured as a field effect transistor that can be operated at different regimes. The sensing results show that the device sensitivity is strongly dependent on the ionic strength in the buffer. The sensitivity can be significantly improved in subthreshold regime in comparison with a floating gate device configuration. With the floating gate configuration, the sensitivity at a streptaviding concentration of 47.3 nM is 11.3% whereas the sensitivity is enhanced to 67.4% at a concentration of 4.73 nM when the device is biased at the subthreshold regime. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties and Judd‐Ofelt parameters of Sm3+ doped BiO1.5‐WO3‐TeO2 glasses
Authors: Fujiwara Takeshi , Hayakawa Tomokatsu , Nogami Masayuki , Duclère Jean‐René , Thomas Philippe 
Published: June 2011

AbstractIn this paper, the optical absorption and emission spectra of Sm3+ ions in 5BiO1.5‐20WO3‐75TeO2 glasses (0.2, 0.5, 1.0, 2.0 and 3.0 mol% of Sm3+) are presented. These glasses have been developed very recently and are found to exhibit excellent third‐order nonlinear properties. A Judd‐Ofelt analysis has been performed in order to calculate various optical parameters such as Judd‐Ofelt parameters, radiative transition probabilities, and stimulated emission cross‐section. According to the computed Judd‐Ofelt parameters, the symmetry of the sites occupied by the Sm3+ ions increased as the amount of Sm2O3 was increased, and the covalency decreased above 1.0 mol%. The results of the stimulated emission cross‐section revealed that the 4G5/2 → 6H7/2 transition of 1.0 mol% Sm3+ in 5BiO1.5‐20WO3‐75TeO2 glasses could be promising for lasing action.Emission spectrum of 1.0 mol% Sm2O3‐doped 5BiO1.5‐20WO3‐75TeO2 glass. Judd‐Ofelt parameters (Ωλ) and peak emission stimulated cross‐section σ (λp) are shown in the figure. The 4G5/2 → 6H7/2 transition is promising for lasing action. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Raman spectra and third‐order nonlinear optical Z‐scan properties of MO‐Nb2O5‐TeO2 (M=Zn, Mg, Ca, Sr, Ba) glasses
Authors: Hayakawa Tomokatsu , Suhara Toshiki , Fujiwara Takeshi , Nogami Masayuki , Thomas Philippe 
Published: June 2011

AbstractIn this paper, the third‐order nonlinear optical susceptibilities, χ(3), of tellurite glasses with MO‐Nb2O5‐TeO2 system (M = Zn, Mg, Ca, Sr, Ba) was investigated by Z‐scan measurement using Ti:Sapphire femtosecond laser pulses. The relationship between the nonlinear optical properties and the glass structures, estimated by Raman spectroscopy, was discussed. The experimental results revealed that when alkaline‐earth ions (M2+) was doped in Nb2O5‐TeO2 binary network system the break in TeIV‐eqOax‐TeIV chain structure necessarily occurred but the terminations of –TeIV‐Oeq‐NbVI‐O‐ + M2+ + ‐Oax‐TeIV‐ or –TeIV‐Oeq‐ + M2+ + ‐O‐NbVI‐Oax‐TeIV‐ were more preferentially induced with an assist of NbO6 polyhedron, which produced TeO3+1 units or stabilized TeIVO4 units (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoluminescence of europium doped LiInO2 powder
Authors: Đačanin Lj. R. , Dramićanin M. D. , Nikolić M. G. , Mitrić M. , Petrović D. M. , Lukić S. R. 
Published: June 2011

AbstractLithium‐indium oxide is one of the candidate materials as solid‐state scintillators for solar neutrinos due to an inverse β–‐decay of 115In to 115Sn. On the other hand, when doped with rare‐earth ions such as Eu3+ or Sm3+, it becomes a promising phosphor material. In this report we present a simple solid‐state procedure for preparation of LiInO2:Eu3+ powders. X‐ray diffraction confirmed prod‐uct in tetragonal structural form (space group: I41/amd) and no impurity phases were detected. Then, high resolution photoluminescence emission measurements were performed at room and low temperatures to find 5D0 → 7FJ. Emission kinetics from 5D0 level exhibited pure single exponential behavior with lifetime of about 1.5 ms. Maximum energy splitting of 7F1 manifold is recorded as a function of temperature (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bulk heterojunction organic photovoltaic cell fabricated by the electrospray deposition method using mixed organic solvent
Authors: Fukuda Takeshi , Takagi Kenji , Asano Takashi , Honda Zentaro , Kamata Norihiko , Ueno Keiji , Shirai Hajime , Ju Jungmyoung , Yamagata Yutaka , Tajima Yusuke 
Published: May 2011

AbstractA high‐efficiency bulk heterojunction organic photovoltaic cell (OPV) was achieved by the electrospray deposition method. The surface roughness of the P3HT:PCBM thin film can be reduced using the mixed solvent consisting of o‐dichlorobenzene (o‐DCB) and acetone. The effect of acetone concentration is related to its dielectric constant. Under an optimized concentration of acetone in o‐DCB (20 vol%), the P3HT/PCBM active layer with a smooth surface can be formed, and the power conversion efficiency of the OPV was 1.9%.magnified image(© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An algebraic approach to the collinear collision N2 + N2 in the semiclassical approximation
Authors: Santiago R. D. , Álvarez‐Bajo O. , Arias J. M. , Gómez‐Camacho J. , Lemus R. 
Published: May 2011

AbstractAn algebraic model to describe the collinear inelastic collision N2 + N2 in the semiclassical approximation is presented. The interactions for the diatomic systems are modeled in terms of Morse potentials, whereas an exponential function is taken for the interactions between the nearest atoms of the diatomic systems. This problem is treated in the interaction picture, where an approximation of the interaction potential in terms of the generators of three SU(2) groups is proposed, two corresponding to the Morse oscillators and the third one to the interaction. The transition probabilities are given in terms of a sum of products of three Wigner's d(β) functions corresponding to the three SU(2) groups. Our results are compared with exact quantum mechanical calculations. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
DFT studies of homogeneous catalysis in the gas phase: Dehydration kinetics of several tertiary alcohols with hydrogen chloride
Authors: Mora Jose R. , Marquez David J. , Marquez Edgar , Loroño Marcos , Cordova Tania , Chuchani Gabriel 
Published: May 2011

AbstractThe mechanisms for the acid‐catalyzed gas‐phase dehydration of the tertiary alcohols 2‐methyl‐2‐propanol, 2‐methyl‐2‐butanol, and 2‐methyl‐2‐pentanol were examined at B3LYP/6‐31G(d), B3LYP/6‐31G(d,p), B3LYP/6‐31G(2d,p), B3LYP/6‐31G(2d,2p), B3PW1/6‐31G(d), B3PW1/6‐31G(d,p), B3PW1/6‐31G(2d,p), B3PW1/6‐31G(2d,2p), MPW91PW91/6‐31G(d), MPW91PW91/6‐31G(d,p), MPW91PW91/6‐31G(2d,p), and MPW91PW91/6‐31G(2d,2p) levels of theory. Calculation results suggest that the dehydration processes catalyzed by hydrogen chloride to give the corresponding olefin and water occur with the formation of Van der Waals complexes between the alcohol and hydrogen chloride. The transition states are six‐membered cyclic structures involving one molecule of HCl and one of the alcohol. These reactions appear to be molecular in nature. Analysis of the progress along the reaction coordinate, in terms of bond orders, NBO charges, and geometrical parameters suggest these reactions to be moderately polar and nonsynchronous and are dominated by the breaking of the HCl bond, together with an important cleavage of CO bond in the transition state. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Modeling for accurate dimensional scanning electron microscope metrology: then and now
Authors: Postek Michael T. , Vladár András E. 
Published: May 2011

AbstractA review of the evolution of modeling for accurate dimensional scanning electron microscopy is presented with an emphasis on developments in the Monte Carlo technique for modeling the generation of the electrons used for imaging and measurement. The progress of modeling for accurate metrology is discussed through a schematic technology timeline. In addition, a discussion of a future vision for accurate SEM dimensional metrology and the requirements to achieve it are presented. SCANNING 33: 114–125, 2011. Published 2011 by Wiley Periodicals, Inc.
Selective response of antigen‐antibody reactions on chiral surfaces modified with 1,2‐diphenylethylenediamine enantiomers
Authors: Zhou Juan , Wang Lilan , Chen Qiao , Wang Yonghua , Fu Yingzi 
Published: June 2011

AbstractThis work reported a comparative analysis of the amperometric responses of antigen‐antibody reactions on two stable chiral surfaces which were modified with 1,2‐diphenylethylenediamine enantiomers. Alpha‐fetoprotein antibody and antigen (anti‐AFP and AFP) were selected as model systems. First, (1R,2R)‐1,2‐diphenylethylenediamine or (1S,2S)‐1,2‐diphenylethylenediamine was modified on the gold surface of the electrode through amide linkage to construct chiral surfaces. Then, anti‐AFP was immobilized on the chiral electrode surface by electrostatic and hydrogen bonding interactions. The electrochemical characteristics of the modified electrodes were studied via cyclic voltammetry. The selective current responses of antigen‐antibody reactions on chiral electrode surfaces for different incubation time and varying AFP concentrations were monitored. The antigen‐antibody reactions were greatly influenced by the chirality of 1,2‐diphenylethylenediamine enantiomers, and the amperometric responses obtained from the (1S,2S)‐1,2‐diphenylethylenediamine modified electrode was obviously stronger than that from the (1R,2R)‐1,2‐diphenylethylenediamine modified electrode. Such work may not only offer valuable reference to the research of chiral drugs, but also help to comprehend the high selectivity of chiral molecular species in biosystems. Copyright © 2011 John Wiley & Sons, Ltd.
The surface behavior of gilding layer imitations on polychrome artefacts of cultural heritage
Authors: Sandu I. C. A , Busani T. , de Sá M. H. 
Published: June 2011

AbstractThis paper proposes the first results of a larger study on the behavior of gilded surfaces of polychrome heritage artefacts with the aim to understanding the surface patterns and roughness variations before and after specific treatments (burnishing and varnishing). This study can be useful to trace correlations between the compositional features, manufacturing and applications/elaboration processes of gilding layers and the pattern of the surface topography, and also some insights into the degradation/corrosion mechanisms. The results obtained on imitations of gilded surfaces can be further useful for recognizing fake surfaces in the authentication of artefacts from the antiquity markets.Two types of commercial imitations of gilded surfaces on a wooden support were considered: liquid ‘gold’ (Cu‐Zn powder in a solvent) and ‘gold’ leaf (Cu‐Zn leaf) applied over bole and gesso layers.A combined analytical approach using atomic force microscopy (AFM), optical microscopy (OM) and colorimetry (CIE L*a*b* system) was applied in order to better understand the behavior of the gilded‐varnished surface and of the interface between the metal surface and the other preparative layers. Copyright © 2011 John Wiley & Sons, Ltd.
Morphology study of layered silicate/chitosan nanohybrids
Authors: Potarniche C. G. , Vuluga Z. , Donescu D. , Christiansen J. de C. , Eugeniu V. , Radovici C. , Serban S. , Ghiurea M. , Somoghi R. , Beckmann S. 
Published: June 2011

AbstractModification of clay with biopolymers has been of high interest in recent years. These new materials may be used for drug delivery systems and as biomaterials due to their high biocompatible properties and because they have the advantage of being biodegradable. The modification of montmorillonite (MMT) with chitosan was done in solution, at ratio 1:2 and at room temperature, or at stages of high temperature, and subjected to a microwave treatment. The influence of pH was observed upon the intercalation process.The obtained materials were characterized through X‐ray diffraction (XRD), thermogravimetrical analyses (TGA), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Using such a mixed treatment, the basal distance of modified MMT increased up to 3.6 nm. The results show the intercalation of chitosan between the layers of MMT and obtaining of intercalated and partial exfoliated nanocomposites. Copyright © 2011 John Wiley & Sons, Ltd.
Flexible ZnO–Cellulose Nanocomposite for Multisource Energy Conversion
Authors: Kumar Ashavani , Gullapalli Hemtej , Balakrishnan Kaushik , Botello‐Mendez Andres , Vajtai Robert , Terrones Mauricio , Ajayan Pulickel M. 
Published: May 2011

AbstractMaterials with the ability to harness multiple sources of energy from the ambient environment could lead to new types of energy‐harvesting systems. It is demonstrated that nanocomposite films consisting of zinc oxide nanostructures embedded in a common paper matrix can be directly used as energy‐conversion devices to transform mechanical and thermal energies to electric power. These mechanically robust and flexible devices can be fabricated over large areas and are capable of producing an output voltage and power up to 80 mV and 50 nW cm−2, respectively. Furthermore, it is shown that by integrating a certain number of devices (in series and parallel) the output voltage and the concomitant output power can be significantly increased. Also, the output voltage and power can be enhanced by scaling the size of the device. This multisource energy‐harvesting system based on ZnO nanostructures embedded in a flexible paper matrix provides a simplified and cost‐effective platform for capturing trace amounts of energy for practical applications.
Self‐Assembled Large Au Nanoparticle Arrays with Regular Hot Spots for SERS
Authors: Chen Aiqing , DePrince A. Eugene , Demortière Arnaud , Joshi‐Imre Alexandra , Shevchenko Elena V. , Gray Stephen K. , Welp Ulrich , Vlasko‐Vlasov Vitalii K. 
Published: June 2011

AbstractThe cost‐effective self‐assembly of 80 nm Au nanoparticles (NPs) into large‐domain, hexagonally close‐packed arrays for high‐sensitivity and high‐fidelity surface‐enhanced Raman spectroscopy (SERS) is demonstrated. These arrays exhibit specific optical resonances due to strong interparticle coupling, which are well reproduced by finite‐difference time‐domain (FDTD) simulations. The gaps between NPs form a regular lattice of hot spots that enable a large amplification of both photoluminescence and Raman signals. At smaller wavelengths the hot spots are extended away from the minimum‐gap positions, which allows SERS of larger analytes that do not fit into small gaps. Using CdSe quantum dots (QDs) a 3–5 times larger photoluminescence enhancement than previously reported is experimentally demonstrated and an unambiguous estimate of the electromagnetic SERS enhancement factor of ≈104 is obtained by direct scanning electron microscopy imaging of QDs responsible for the Raman signal. Much stronger enhancement of ≈108 is obtained at larger wavelengths for benzenethiol molecules penetrating the NP gaps.
Three‐dimensional sonography of the posterior fossa in fetuses with open spina bifida at 11–13 weeks' gestation
Authors: Scheier M. , Lachmann R. , Pětroš M. , Nicolaides K. H. 
Published: May 2011

AbstractObjectivesTo investigate the posterior fossa of normal fetuses and fetuses with open spina bifida in stored three‐dimensional (3D) volumes and to describe signs that might allow early detection of this defect.MethodsA prospective study of 3D volumes of the fetal brain obtained from 10 normal fetuses and three fetuses with open spina bifida was undertaken. Measurements of the anteroposterior diameters of the cisterna magna and fourth ventricle were taken in the tilted axial view. In the mid‐sagittal plane the brainstem (BS) diameter and the brainstem–occipital bone (BSOB) distance were measured. The BS/BSOB ratio was calculated. All measurements were expressed as Z‐scores. Structural analysis of the differences in the posterior fossa between normal fetuses and fetuses with open spina bifida was undertaken.ResultsIn normal fetuses all measurements were within ± 2.5 Z‐scores. In three fetuses with open spina bifida the BS Z‐scores were 2.7, 2.8 and 2.8; the BSOB scores were − 3.4, − 2.8 and − 2.9; the cisterna magna scores were − 5.6, − 3.7 and − 4.2; and the BS/BSOB ratio scores were 4.1, 9.7 and 8.9. In normal fetuses the cisterna magna was posterior to the fourth ventricle and extended along its entire length. In fetuses with open spina bifida the cisterna magna was partially or completely obliterated.ConclusionsAssessment of the cranial posterior fossa is feasible at 11–13 weeks' gestation. There are distinct signs in fetuses with open spina bifida which can be evaluated by ultrasonography. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Syntheses, Crystal Structures, and Luminescence Properties of Dinuclear Metal (Ag+ and Cu+) Complexes with the Ligand 2‐MTPP [2‐MTPP = 2‐(Methylthio)‐4‐(pyridin‐2‐yl)pyrimidine]
Authors: Zhu Hai‐Bin , Zhang Shu‐Ying , Lu Xin , Yang Wen‐Na , Gou Shao‐Hua , Chen Jing 
Published: May 2011

AbstractReactions of the ligand 2‐MTPP [2‐MTPP = 2‐(methylthio)‐4‐(pyridin‐2‐yl)pyrimidine] with AgNO3 and CuI produced dinuclear silver(I) (1) and copper(I) (2) complexes, respectively. Both complexes adopt a chair‐like structure in which two 2‐MTPP ligands and two metal ions are joined together through M–N and M–S coordination bonds. The luminescence properties of both complexes were investigated in solid state at room temperature.