bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atom probe extended to AlGaN: three‐dimensional imaging of a Mg‐doped AlGaN/GaN superlattice
Authors: Bennett Samantha E. , Clifton Peter H. , Ulfig Robert M. , Kappers Menno J. , Barnard Jonathan S. , Humphreys Colin J. , Oliver Rachel A. 
Published: April 2010

AbstractLaser pulsed atom probe tomography (APT) can provide three‐dimensional chemical and spatial information in semiconductor materials, revealing buried features at the nanoscale. In this investigation, a Mg‐doped AlGaN/GaN superlattice was studied using laser pulsed APT. Such superlattices are commonly used to overcome the intrinsically low doping efficiency of Mg. Although the superlattice was nominally doped to the same level throughout, secondary ion mass spectrometry (SIMS) suggested a greater Mg content in the AlGaN layers.The APT data provided three‐dimensional element mapping and revealed clustered Mg in both the GaN and AlGaN layers. These clusters are shown to be statistically significant when compared to a random distribution of Mg. More clusters were found in the AlGaN layers, suggesting that the presence of clusters accounts for the higher Mg level in the AlGaN layers that was suggested by SIMS. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth mechanism of nonpolar m ‐plane GaN on maskless patterned a ‐plane sapphire substrate
Authors: Kawashima Yuji , Murakami Kazuma , Abe Yuki , Okada Narihito , Tadatomo Kazuyuki 
Published: April 2010

AbstractWe grew nonpolar m ‐plane GaN by selective area growth and epitaxial lateral overgrowth. In this report, we investigated the growth mechanism of m ‐plane GaN on a patterned a ‐plane sapphire substrate (a ‐PSS) without an SiO2 mask. With the control of the anisotropic growth rate of c ‐plane GaN on an original a ‐plane sapphire surface and on a c ‐plane‐like sapphire sidewall in the a ‐PSS, c ‐plane GaN was grown only on the c ‐plane‐like sapphire sidewall, resulting in a pure‐oriented m ‐plane GaN layer on the a ‐PSS. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of slight misorientations of r ‐plane sapphire substrates on the growth of nonpolar a ‐plane GaN layers via HVPE
Authors: Schwaiger Stephan , Lipski Frank , Wunderer Thomas , Scholz Ferdinand 
Published: April 2010

AbstractWe have investigated the growth of nonpolar GaN templates by hydride vapor phase epitaxy (HVPE). This includes a systematic study of misoriented r‐plane sapphire wafers with a miscut angle up to ±1° towards the c‐axis of the crystal as starting substrates. Starting with an AlN nucleation layer approximately 3.3 μm of nonpolar a‐plane GaN are grown by metalorganic vapor phase epitaxy (MOVPE). The subsequent growth by HVPE was optimized to obtain flat and homogeneous layers with very good crystal quality. This was illustrated by very small full widths at half maximum (FWHM) of x‐ray rocking curve (XRC) measurements of less than 500 arcsec.The surface quality was evaluated by scanning electron microscopy (SEM) and optical phase contrast microscopy showing a high number of surface defects (pits) for the samples with a high miscut towards the positive direction whereas a slight miscut of +0.5° reduces the surface roughness. Additionally, smallest XRC FWHM values have been obtained for this particular miscut. A miscut towards negative directions results in lower crystalline quality and the surfaces shows hillock‐like features. All GaN layers on misoriented substrates are tilted with respect to the substrate. Their tilt angle increases with the miscut angle. Its direction is opposed to the miscut of the sapphire. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Energy landscape and carrier wave‐functions in InGaN/GaN quantum wells
Authors: Watson‐Parris D. , Godfrey M. J. , Oliver R. A. , Dawson P. , Galtrey M. J. , Kappers M. J. , Humphreys C. J. 
Published: April 2010

AbstractLocalisation lengths of the electrons and holes in InGaN/GaN quantum wells have been calculated using numerical solutions of the effective mass Schrödinger equation. We have treated the distribution of indium atoms as random and found that these fluctuations in alloy concentration alone can localise the carriers. While the holes are localised on a scale of approximately ∼1nm, the electrons are localised on scale of ∼7 nm. We have also considered the effect of well width fluctuations and found that they contribute to electron localisation. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Temperature dependence of InN growth on (0001) sapphire substrates by atmospheric pressure hydride vapor phase epitaxy
Authors: Kumagai Yoshinao , Adachi Hirokazu , Otake Aya , Higashikawa Yoshihiro , Togashi Rie , Murakami Hisashi , Koukitu Akinori 
Published: April 2010

AbstractThe temperature dependence of InN growth on (0001) sapphire substrates by atmospheric pressure hydride vapor phase epitaxy (HVPE) was investigated. N‐polarity single‐crystal InN layers were successfully grown at temperatures ranging from 400 to 500 °C. The a and c lattice constants of InN layers grown at 450 °C or below were slightly larger than those of InN layers grown above 450 °C due to oxygen incorporation that also increased the carrier concentration. The optical absorption edge of the InN layer decreased from above 2.0 to 0.76 eV when the growth temperature was increased from 450 to 500 °C. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
InGaN/GaN LEDs grown on Si(111): dependence of device performance on threading dislocation density and emission wavelength
Authors: Zhu Dandan , McAleese Clifford , Häberlen Maik , Salcianu Carmen , Thrush Ted , Kappers Menno , Phillips Andrew , Lane Penelope , Kane Michael , Wallis David , Martin Trevor , Astles Mike , Humphreys Colin 
Published: April 2010

AbstractWe demonstrate the growth of crack‐free blue and green‐emitting LED structures grown on 2‐inch and 6‐inch Si(111) substrates by metalorganic vapour phase epitaxy (MOVPE), using AlN nucleation layers and AlGaN buffer layers for stress management. LED device performance and its dependence on threading dislocation (TD) density and emission wavelength were studied. Despite the inherently low light extraction efficiency, an output power of 1.2 mW at 50 mA was measured from a 500 μm square planar device, emitting at 455 nm. The light output decreases dramatically as the emission wavelength increases from 455 nm to 510 nm. For LED devices emitting at similar wavelength, the light output was more than doubled when the TD density was reduced from 5 × 109 cm‐2 to 2 × 109 cm‐2. Our results clearly show that high TD density is detrimental to the overall light output, highlighting the need for further TD reduction for structures grown on Si. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A novel bio‐functionalization of AlGaN/GaN‐ISFETs for DNA‐sensors
Authors: Linkohr Stefanie , Schwarz Stefan , Krischok Stefan , Lorenz Pierre , Cimalla Volker , Nebel Christoph , Ambacher Oliver 
Published: April 2010

AbstractAlGaN/GaN pH sensitive devices were functionalized and passivated for the use as selective biosensors. For the passivation, a multilayer of SiO2 and SiNx is proposed, which stabilizes the pH‐sensor, is biocompatible and has no negative impact on the following bio‐functionalization. The functionalization of the GaN‐surface was achieved by covalent bonding of 10‐amino‐dec‐1‐ene molecules by a photochemical process. After exposure to ultraviolet light, islands of TFAAD are growing on the sensor surface. After 3 h exposure one monolayer is completed. Further exposure results in thicker films as a consequence of polymerization. The bonding to the sensor surface was analyzed by x‐ray photo electron spectroscopy, while the thickness of the functionalization was determined by atomic force microscopy scratching experiments. These functionalized devices based on the pH‐sensitive AlGaN/GaN ISFET will establish a new family of adaptive, selective biomolecular sensors such as selective, reusable DNA sensors. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fraction of design space plots for evaluating ridge estimators in mixture experiments
Authors: Jang Dae‐Heung , Anderson‐Cook Christine M. 
Published: April 2010

AbstractWhen the component proportions in mixture experiments are restricted by lower and upper bounds, the design space can become an irregular region that can induce multicollinearity among the component proportions. Thus, we suggest the use of ridge regression as a means of stabilizing the estimates of the coefficients in the fitted model. We use fraction of design space plots and violin plots to illustrate and evaluate the effect of ridge regression estimators with respect to the prediction variance and to guide the decision about the value of ridge constantk. We illustrate the methods with three examples from the literature. Copyright © 2010 John Wiley & Sons, Ltd.
Patient‐specific simulation for endovascular procedures: qualitative evaluation of the development process
Authors: Willaert W. I. M. , Aggarwal R. , Nestel D. F. , Gaines P. A. , Vermassen F. E. , Darzi A. W. , Cheshire N. J. 
Published: April 2010

AbstractBackgroundRecent advancements in simulation permit patient‐specific rehearsal of carotid artery stenting procedures. This study evaluates the feasibility of transferring patient‐specific CT data into the simulator, creating a 3D reconstruction and performing a rehearsal. The face validity of the model was assessed.Methods/ResultsBy thematic analysis of qualitative data, an algorithm was generated, focusing on simulation set‐up, time of data transfer, software/compatibility issues and problem‐solving strategies. The face validity of the simulated case was evaluated by 15 expert interventionalists: realism (median 4/5), training potential (median 4/5) and pre‐procedure rehearsal potential for challenging CAS cases (median 4/5) were rated highly.ConclusionsSetting up a procedure rehearsal is feasible and reproducible for different patients in different hospital settings without major software compatibility issues. The time to create a 3D reconstruction of patient‐specific CT data is a major factor in the total time necessary to set up a rehearsal. The face validity is highly rated by experts. Copyright © 2010 John Wiley & Sons, Ltd.
Kinetics of rhodium electrodeposition for semiconductor interconnect applications
Authors: Son Seong‐Ho , Lee Hong‐Kee , Park Sung‐Cheol 
Published: April 2010

AbstractIn this study, reaction mechanism of rhodium electrodeposition process for semiconductor interconnection was investigated using rotating disk electrode. To clarify the rate determining step, the activation energy (Ea) of the rhodium electrodeposition was calculated from the Arrhenius plot in the temperature range of 25–65 °C. Experimental Eaof rhodium was 3.25 kcal/mole, indicating that electrodeposition rate is controlled by mass transfer. The effects of additives on bottom‐up filling were also investigated by varying species of accelerators, suppressors and levelers. The effect of filling rhodium into nano‐scale trench was evaluated using various combinations of accelerators, suppressors and levelers. After rhodium electrodeposition using polymer type suppressor and sulfide bond type accelerator, the superconformal electrodeposited layer was obtained without seams and voids. Addition of azole type leveler to the above electrolyte led to decrease in topographic variations of rhodium electrodeposit, resulting in increase of flatness. As a result, nano‐scale trenches (apppproximately 50–300 nm) were filled forming void‐free and seam‐free superconformal electrodeposited layers through the optimized selection of the additives. Copyright © 2010 John Wiley & Sons, Ltd.
Heating modification of an austenitic steel with high‐nitrogen content
Authors: Carosi A. , Amati M. , Gregoratti L. , Kaciulis S. , Mezzi A. , Montanari R. , Rovatti L. , Ucciardello N. 
Published: April 2010

AbstractThe micro‐structural changes of an austenitic steel with high‐nitrogen content have been investigated after heat treatments at 850 °C. Micro‐chemical composition of heat‐induced structures was analyzed using XPS, multipoint AES and photoemission spectro‐microscopy. Before the XPS, AES and photoemission spectro‐microscopy analyses, the samples were cleaned in situ by Ar ion sputtering. The results show that the discontinuous precipitation of Cr2 N from the nitrogen supersaturated γs phase is accompanied by a net flux of nitrogen toward the transformed zones, thus confirming that the principal force behind boundary migration is the nitrogen concentration gradient between the γ and γs phases. When γ and γs reach the same nitrogen concentration, the precipitation stops even if the transformation of the matrix has not yet been completed. Copyright © 2010 John Wiley & Sons, Ltd.
Role of the surface in Li insertion into nanowires of TiO2‐B
Authors: Koudriachova M. V. 
Published: April 2010

AbstractNanostructured TiO2‐B is considered to be one of the most promising new anode materials for Li rechargeable batteries, exhibiting highly desirable properties of high capacity, good reversibility, and exceptionally fast Li‐insertion. Recently, it has been demonstrated that nanowires of TiO2‐B may act as capacitors for Li‐ions in a wide range of Li concentrations. In this paper, we examine the sites and energetics of Li absorption, the barriers for Li‐self‐diffusion and the low‐energy pathways from the surface into the interior through advanced simulation techniques. The simulations show that the relative stability of the sorption sites is affected by the surface, which constrains the structural anisotropic expansion of lithiated TiO2‐B. We pinpoint the mechanisms responsible for exceptionally fast transport of Li ions and uncover the crucial role of the high surface area with an abundance of absorption sites. Each of the surface absorption sites is connected to the interior through a low‐energy radial pathway, which brings an absorbed Li ion to its trapping site almost independently, contributing to pseudocapacitive behavior of TiO2‐B nanowires with respect to Li‐ions. We show that the curvature of the surface restricts the intercalation performance of nanowires and predict that (stretched) nanoribbons will exhibit superior properties. Copyright © 2010 John Wiley & Sons, Ltd.
Influence of thermal annealing on the structure and optical properties of d.c. magnetron sputtered titanium dioxide thin films
Authors: Kars İ. , Çetin S. Ş. , Kınacı B. , Sarıkavak B. , Bengi A. , Altuntaş H. , Öztürk M. K. , Özçelik S. 
Published: April 2010

AbstractTitanium dioxide (TiO2) thin films were deposited on glass substrate by d.c. magnetron sputtering at 200 °C substrate temperature. The thicknesses of the films were measured using stylus type profilometer. The deposited films were annealed using rapid thermal annealing (RTA) system in the O2 ambient for 20 min at 400 and 500 °C. Influence of Ar/O2 flux ratio and annealing temperature on structural and optical properties of the samples was analyzed using X‐ray diffraction (XRD) and UV–vis spectrometer in the range of 200–1100 nm. The films annealed above 400 °C were crystalline with anatase phase, whereas at the as‐deposited states, the films were amorphous. Optical properties such as band gap, refractive index and absorption coefficient were calculated using transmittance spectra of the samples. The influence of thermal annealing on structure and optical properties is discussed. Band gap energies of the TiO2 films were also determined using photoluminescence(PL) measurements. Copyright © 2010 John Wiley & Sons, Ltd.
Extracting interdiffusion parameters from Ni/Cu thin films by means of profile reconstruction with the MRI model
Authors: Joubert H. D. , Terblans J. J. , Swart H. C. 
Published: April 2010

AbstractThin film diffusion studies often involve a surface‐sensitive analysis technique combined with ion erosion to produce a depth profile of a sample. Such studies compare the depth profile of a reference sample to the depth profiles of samples that were annealed at different temperatures and times. The extent to which atoms of one layer diffuse into an adjacent layer, for a particular temperature and time, yields information on the diffusion process involved and allows quantification of the diffusion coefficient. The drawback to using an erosion‐type system is the effect of the incident ions on the surface being probed. The Mixing‐Roughness‐Information model attempts to compensate for this effect and is often employed as a means of quantification of measured depth profiles by means of profile reconstruction. Used in conjunction with Auger electron spectroscopy, the Mixing‐Roughness‐Information (MRI) model is a useful tool to reconstruct the ion erosion depth profiles as well as extracting interdiffusion parameters from these depth profiles. This study focuses on the extraction of the diffusion coefficient of Ni in Cu from Ni/Cu depth profiles obtained from ion erosion Auger electron spectroscopy. The resultant depth profiles were reconstructed with the MRI model. The diffusion coefficient for Ni diffusing in Cu was obtained from the MRI fit and it compared well to values available in literature. Copyright © 2010 John Wiley & Sons, Ltd.
Influence of the contact angle on two‐phase flow in microreactors for nitrobenzene–hydrogen–stainless steel/carbon
Authors: Özkan Furkan , Hecht Kristin , Pfeifer Peter , Schubert Klaus , Kraushaar‐Czarnetzki Bettina 
Published: April 2010

AbstractThe contact angle of a gas–liquid–solid system plays a significant role in predicting flow patterns in microchannels for multiphase flows. The contact angle, which is a result of surface forces, is strongly influenced by the channel material. In the present study, we describe contact angle measurements and simulations of flow in a microchannel for the multiphase system hydrogen and nitrobenzene. Contact angles for nitrobenzene–hydrogen–stainless steel and nitrobenzene–hydrogen–carbon systems were measured using the sessile drop method at various pressures. Simulation of the two‐phase system was performed using ANSYS FLUENT. The static contact angle is used as a boundary condition. The results from simulation of flow for a wide range of contact angles and the measured contact angles are presented. Experimental observations and simulation results agree in that the contact angle must be smaller 90° to obtain small bubbles and to increase the gas–liquid interfacial surface area. Copyright © 2010 John Wiley & Sons, Ltd.
Synthesis and Characterization of Sodium Nonylphenol Ethoxylate(10) Sulfoitaconate Esters
Authors: Ding Junwei , Song Bin , Wang Chuanxing , Xu Jun , Wu Yumin 
Published: April 2010

AbstractTwo sodium nonylphenol ethoxylate(10) sulfoitaconate ester surfactants, namely disodium nonylphenol ethoxylate(10) sulfoitaconate monoester (DNE(10)SIM) and sodium nonylphenol ethoxylate(10) sulfoitaconate diester (SNE(10)SID), were synthesized through the esterification and sulfonation reactions with nonylphenol ethoxylate(10) ester, itaconic acid and sodium sulfite as the raw materials. The chemical structures of the prepared surfactants were confirmed by FTIR and 1H NMR. The surface tension of the synthesized surfactants was measured at 25 °C and the surface active properties were characterized. The DNE(10)SIM had better surface activity. The CMC was 1.77 × 10−6 mol L−1 and γCMC was 35.45 mN m−1. The CMC and γCMC for the SNE(10)SID were 5.42 × 10−5 mol L−1 and 37.67 mN m−1, respectively. Moreover, the emulsification power of SNE(10)SID was better.
Pecipamide, a New Sphingosine Derivative from the Cultures of Polyporus picipes (Basidiomycetes)
Authors: Li Yong , Ma Ya‐Tuan , Kuang Yi , Gao Jin‐Ming , Qin Jian‐Chun 
Published: April 2010

AbstractA new C18‐ceramide congener named pecipamide (1), together with the known ergosta‐4,6,8(14),22‐tetraen‐3‐one (2), was isolated from the solid fermentations of the basidiomycetous fungus Polyporus picipes. The structure of the new metabolite was established as (2′R,2S,3R)‐N‐2′‐hydroxyheptadecanoyl‐2‐amino‐octadecane‐1,3‐diol on the basis of spectroscopic data, including 1D‐ and 2D‐ nuclear magnetic resonance spectroscopy (NMR) experiments, as well as by means of mass spectrometric measurements (MS).
Fatty Acid Composition of the Maternal Diet During the First or the Second Half of Gestation Influences the Fatty Acid Composition of Sows' Milk and Plasma, and Plasma of Their Piglets
Authors: Amusquivar Encarnación , Laws John , Clarke Lynne , Herrera Emilio 
Published: April 2010

AbstractDietary supplements of olive oil (OO) or fish oil (FO) during the first (G1: day 1–60) or second half of gestation (G2: day 60 to term, day 115) were offered to pregnant sows. The proportion of fatty acids in milk and plasma were determined by gas chromatography. When supplements were given during G1, the proportions of oleic acid (OA) and arachidonic acid (AA) in the plasma were higher in the OO group than in the FO group, whereas docosahexaenoic acid (DHA) was higher in the latter group at day 56 of gestation. These differences in plasma DHA were still apparent at day 7 of lactation. Similarly, DHA was also higher in the colostrum and milk on days 3 and 21 of lactation and in the plasma of piglets from FO dams compared to the OO group, whereas AA was lower. When the FO supplement was given during G2, AA was lower and DHA higher in the plasma at day 105 of gestation and at day 7 of lactation compared with the OO group. Likewise, DHA was greater in FO than in OO animals during lactation in colostrum and in milk on days 3 and 21 of lactation, and in 3‐day old suckling piglets plasma, whereas AA was lower in these animals. Thus, maternal adipose tissue plays an important role in the storage of dietary long‐chain polyunsaturated fatty acids (LCPUFA) during G1. They are mobilized around parturition for milk synthesis, and an excess of dietary n‐3 LCPUFA decreases the availability of AA in suckling newborns.
Postharvest Heat Treatment for Olive Oil Debittering at the Industrial Scale
Authors: Yousfi Khaled , Moyano Maria J. , Martinez Fernando , Cayuela José A. , Garcia José M. 
Published: April 2010

AbstractTo enhance the debittering of olive oil, 500‐kg olive fruit (Olea europaea L.) samples in duplicate from different olive cultivars and orchard locations in Spain (Manzanilla olive fruits from Villarrasa during the 2002/2003, 2004/2005 and 2005/2006 seasons, or from Dos Hermanas during the 2004/2005 and 2005/2006 seasons, Picual olive fruits from Cabra during the 2004/2005 season and Verdial olives from Villarrasa during the 2004/2005 and 2005/2006 seasons) were treated by dipping in hot water under different conditions (50–68 °C for 3 or 5 min), which had been previously determined based on laboratory‐scale experiments, and subsequently processed for virgin olive oil extraction. Heat treatment produced a change in the intensity of the oil bitterness in all cases, increased the pigment content, decreased stability and reduced the sensory freshness of the oil. Although heat treatment reduced the phenolic content of the oil, this effect was not uniform among the different phenolic compounds and depended on the crop season and olive variety. Therefore, the determination of debittering conditions will require a series of preliminary laboratory‐scale experiments.