bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reducing the warpage and dislocation density of GaN template grown by HVPE with gallium droplet treatment
Authors: Choi Young Jun , Oh Hae‐Kon , Kim Jung‐Gyu , Hwang Hyun‐Hee , Lee Hae‐Yong , Lee Won‐Jae , Shin Byoung‐Chul , Hwang Jonghee 
Published: May 2010

AbstractThe warpage of the GaN template grown by a HVPE with gallium droplet treatment (GDT) was 13.8 μm, which was reduced by 80.3% of the warpage for GaN template grown by conventional MOCVD and 43% of the warpage for GaN template grown by HVPE without GDT. The treatment of gallium droplets on sapphire was achieved by thermal evaporator at room temperature. The E2 high peak of GaN template with GDT showed at 566.5 cm‐1, whereas the E2 high peak of GaN template by MOCVD positioned at 569.5 cm‐1 in Raman scattering spectra. According to the frequency shifts of E2 high peak position for each template around 3 cm‐1, the release of compressive stress of GaN template grown by HVPE with GDT was shown. In study of FE‐SEM and Grow discharge spectroscopy (GDS), voids and concentration decline zones of gallium and aluminium in counter direction were formed at the interface between GaN epilayer and sapphire substrate during GaN growth by HVPE. We expected that the decrease of warpage and stress for GaN template with GDT could be caused by the formation of voids and concentration decline zones of gallium and aluminium. Etch pits density of GaN template with GDT was around 8.5x107/cm2. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis and evaluation of large‐scale river restoration planning in Germany to better link river research and management
Authors: Kail J. , Wolter C. 
Published: May 2010

AbstractIn December 2008, the draft programmes of measures (PoM) have been published in the EU member states, which list the measures that will be taken to enhance the ecological status of surface and groundwater bodies, and to reach the environmental objectives of the EU‐Water Framework Directive (WFD). We have analysed the German PoM to identify the main pressures and the restoration measures water managers planned to implement in streams and rivers. The objective was to evaluate the PoM and to identify the main, practically relevant knowledge gaps in river management on which applied river research should focus on.In general, the selection of measures in the PoM was reasonable. In accordance with the analysis of pressures and impacts in Germany, the PoM focussed on measures addressing morphological alterations and river continuity, and the results indicated that diffuse source pollution and fine sediment input were additional main pressures in Central European streams and rivers. Although point source pollution was not a main pressure in most rivers, respective point source measures have been selected for many water bodies. Apparently, these were so‐called basic measures that have to be taken due to other EU‐Directives or national laws. Therefore, although in line with the WFD, it seemed doubtful if the point source measures would help to substantially enhance the ecological status. Furthermore, the results indicated that there was a general lack of knowledge on the effect of restoration measures and a specific knowledge gap in how to enhance the ecological state of heavily modified water bodies (HMWB) in the lowland region with a high land‐use pressure, which was reflected by the high share of water bodies for which conceptual measures have been selected (e.g. developing management plans).Based on the analysis of the PoM and a literature review, we identified the following, practically relevant knowledge gaps in river management: (i) the morphodynamics of river reaches where natural channel dynamics have been restored, (ii) the combined effect of measures addressing diffuse nutrient and fine sediment input at different spatial scales (e.g. riparian buffer strips and land‐use changes), (iii) methods to identify suitable and efficient measures and to define environmental objectives for HMWB and (iv) the effect of measures on less well‐studied biological groups like macrophytes and phytoplankton. There is a strong need to summarize recent research results on these issues, to identify the knowledge gaps and research needs in detail, and to make the results of such a comprehensive literature review or meta‐analysis available for the next 6‐year management cycle and second WFD management plans. Copyright © 2010 John Wiley & Sons, Ltd.
Land‐use effects on water quality of a first‐order stream in the Ozark Highlands, mid‐southern United States
Authors: Brion G. , Brye K. R. , Haggard B.E. , West C. , Brahana J.V. 
Published: May 2010

AbstractUrban and agricultural land uses can alter the natural hydrologic conditions of streams and rivers and often degrade water quality. In the Ozark Highlands of the mid‐southern United States, the climate, topography, soil properties, karst limestone geology, agricultural practices and rapid urbanization make water quality of particular concern due to the increased potential for water quality degradation by contaminant leaching to groundwater and runoff to surface waters. The objective of this study was to evaluate the effects of season (i.e. dry/cool and wet/warm) and riparian land use (i.e. urban, grazed pasture, ungrazed pasture, wetland, cultivated agriculture and grassland) on surface water quality in a first‐order stream within a diverse agricultural watershed in the Ozark Highlands. Water samples were collected twice a month within each land use during base‐flow conditions from October 2006 through October 2007. Samples were also collected periodically during storm‐flow conditions from October 2006 through December 2007. The greatest in‐stream pH was adjacent to the grazed pasture. In‐stream NO3‐N concentrations were greatest adjacent to the cultivated agriculture and grassland during the dry/cool season (i.e. October 2006 to March 2007) and averaged 2.67 mg L−1. In‐stream soluble reactive P (SRP) concentrations were greatest adjacent to the grassland during the wet/warm season (i.e. April 2007 to October 2007) and averaged 0.81 mg L−1. Concentrations of SRP, K, Mg and Zn were greater during storm‐ than base‐flow conditions and in‐stream As concentrations frequently exceeded 0.01 mg L−1. Discharge and in‐stream NH4‐N concentrations were unaffected by land use or season and averaged 0.003 m3 s−1 and 0.10 mg L−1, respectively, across all land uses and seasons. Results of this study clearly demonstrate the significant effect of adjacent land use on in‐stream water quality of a first‐order stream in a diverse agricultural watershed and highlight the importance of managing upstream land use in order to regulate downstream water quality. Copyright © 2010 John Wiley & Sons, Ltd.
Surface characterisation of boron nitride layers on multiwalled carbon nanotubes
Authors: Mohai M. , Mohai I. , Sebestyén Z. , Gergely A. , Németh P. , Szépvölgyi J. 
Published: May 2010

AbstractMultiwalled carbon nanotubes (MWCNTs), because of their unique morphology and physico‐chemical properties, have many potential advantages in nanotechnology, electronics, optics and other fields of material science. Their use is limited by their sensibility to oxidation, especially at high temperatures. The chemical resistance of MWCNTs could be increased by coating with non‐oxides, e.g. boron nitride (BN) layers. The aim of the present work was to study the formation of BN thin films on MWCNTs by thermal treatment. Thin films of BN were deposited on MWCNTs surfaces by dip coating of boric acid solutions and high temperature nitriding in ammonia flow. Surface composition and chemical states of the layers were determined by X‐ray photoelectron spectroscopy. The surface layer thickness was also calculated based on XPS data, applying the Layers‐on‐Cylinder model of the XPS MultiQuant program. Resistance of the coated MWCNTs against high temperature oxidation was tested by thermogravimetric analysis. The morphology was investigated by transmission electron microscopy. Copyright © 2010 John Wiley & Sons, Ltd.
Fabrication and characterization of the microporous and nanoporous anodic oxidations of titanium–silver alloys
Authors: Kim Si‐Eun , Lee Sang‐Bae , Park Jeong‐Jong , Kim Kwang‐Mahn , Kim Kyoung‐Nam 
Published: May 2010

AbstractThe purpose of this study was to fabricate and evaluate the morphological structure of microporous anodic oxidation (MAO) or nanoporous anodic oxidation (NAO) treated titanium‐silver (Ti‐Ag) alloys. The Ti‐Ag alloys were arc melted, homogenized, and quenched in water at room temperature. The MAO treatment was performed using β‐glycerol phosphate (β‐GP) and calcium acetate (CA) solution; the NAO treatment was performed using hydrofluoric acid (HF) solution or ammonium fluoride (NH4F) solution. Surface‐treated Ti‐Ag alloys were compared to commercially pure titanium (cp Ti). The surface morphology and phase state were analyzed by field emission scanning electron microscopy (FE‐SEM) and high resolution X‐ray diffraction (HR‐XRD). Both the MAO treated cp Ti and Ti‐Ag alloy samples presented a regular oxide layer with a diameter of approximately 1–3 µm. Morphology was clearly visible on NAO Ti‐Ag alloy samples treated with NH4F solution, with a diameter of roughly 100 nm. However, HF solution treated NAO Ti‐Ag alloy samples appeared to be sparsely‐ and irregularly‐shaped, ranging in size from a few nanometers to 100 nm. From the HR‐XRD analysis, amorphous TiO2, Ti, and Ti‐Ag phases were observed in the MAO and NAO treated Ti‐Ag alloys. The MAO and NAO treated cp Ti samples only showed peaks associated with Ti. The surface characteristics of Ti‐Ag alloys may possibly influence cell viability. Copyright © 2010 John Wiley & Sons, Ltd.
The features of copper oxidation by the data of photocurrent and photopotential studies
Authors: Vvedenskii A. , Grushevskaya S. , Ganzha S. , Maksimova S. 
Published: May 2010

AbstractThe anodic formation of Cu(I) and Cu(II) oxides on polycrystalline copper in deaerated alkaline solution was investigated using the synchronous transients of current and photocurrent (in the potentiostatic polarization mode) as well as the synchronous transients of photopotential and corrosion potential (in the current interruption mode). It was established that copper is subject to corrosion oxidation by the traces of the dissolved oxygen. The formation of the anodic Cu(I) oxide layer hampers further oxidation of copper.A p‐type conductivity was established for Cu2O and CuO oxides formed on copper during both the anodic polarization and the corrosion. Cu(I) oxide film is thin, i.e. its thickness does not exceed the thickness of the space charge region. The band gap of Cu(I) oxide is equal to 2.2 eV for indirect optical transitions. The anodic polarization in the potential range of CuO formation results in the formation of a thicker oxide film which is a mixture of Cu(I) and Cu(II) oxides. Copyright © 2010 John Wiley & Sons, Ltd.
Titanium nitride with silicon additions for tribological applications
Authors: Zimowski S. , Rakowski W. , Grzonka J. 
Published: May 2010

AbstractMicrostructure and mechanical properties of duplex treated system with (Ti,Si)N coating on nitrided stainless steel were investigated. The (Ti,Si)N coatings with the thickness of 1 µm were deposited on nitrided 316L stainless steel substrate by reactive single target magnetron sputtering. The stainless steel was glow discharge nitrided at 450 °C temperature. The transmission electron microscopy (TEM) showed that the coatings were built of heavily defected fine columnar crystallites. The adherence of the coatings to their substrates was examined by scratch test. The highest hardness was measured for the coatings obtained from TiSi4 target (4 at.% Si) and reached maximum of 23 GPa and 27 GPa on not nitrided and nitrided steel respectively. The tribological behaviors of the duplex system were studied in ball‐on‐disc friction test. The (Ti,Si)N coating on nitrided steel exhibited better tribological properties than the nitrided steel without any coating and coating on not nitrided steel. The (Ti,Si)N coatings presented low friction coefficient (0,1–0,2) up to the coating failure. The nitrided steel and duplex system with (Ti,Si)N coating showed essential wear reduction as compared with 316L steel. The observed improvement in coating micromechanical properties with increasing silicon additions is a direct result of their higher hardness caused by grain refinement and more dislocated microstructure. Copyright © 2010 John Wiley & Sons, Ltd.
Protein‐functionalized ultrathin glycidyl methacrylate polymer grafts on gold for the development of optical biosensors : an SPR investigation
Authors: Bernand‐Mantel D. , Chehimi M. M. , Millot M. C. , Carbonnier B. 
Published: May 2010

AbstractThis contribution describes the use of surface plasmon resonance (SPR) technique to fully characterize polymer‐based immunosensing surfaces. Bovine serum albumin (BSA), selected as model biomacromolecule probe, was covalently immobilized on a gold substrate via a poly(glycidyl methacrylate) (PGMA) thin film. Optical characterization was performed at the various steps of the sensor preparation and application. SPR measurements were performed first in static mode to characterize both PGMA and BSA films as well as in dynamic mode to monitor the immunocapture of antibovine serum albumin (a‐BSA) and further study the regenerability of the surface at the level of the antigen layer. Effect of the preparation method of PGMA films, based on either grafting‐onto or grafting‐from approaches, on the immunosensor efficiency was studied. In all cases, the sensing surface could be efficiently regenerated by using an acidic glycine solution without noticeable loss of activity demonstrating the usefulness of poly(glycidyl methacrylate) spacers. Copyright © 2010 John Wiley & Sons, Ltd.
Determining the surface acidic properties of solid catalysts by amine titration using Hammett indicators and FTIR‐pyridine adsorption methods
Authors: Topaloǧlu Yazıcı D. , Bilgiç C. 
Published: May 2010

AbstractSurface acidity of solids (ZSM‐5 zeolites, Y zeolite, mordenite and Ca‐bentonite) were investigated with Fourier transform infrared spectroscopy (FTIR) and Hammett acidity functions; the n‐butylamine titration method. In the amine titration method, acid strength of solids were found. The total acid amount of Y zeolite has the highest value among all others. The IR spectrums of all samples were recorded using diffuse reflectance infrared Fourier transform (DRIFT) technique. Pyridine adsorption and desorption processes have given some clues about the surface acidity of solids. Copyright © 2010 John Wiley & Sons, Ltd.
Influence of nitrogen implantation on the localized corrosion resistance of different tempers of AA7075 aluminium alloy
Authors: Abreu C. M. , Cristóbal M. J. , Figueroa R. , Pena G. , Pérez M. C. 
Published: May 2010

AbstractThis paper reports the study of the effect of nitrogen implantation on the localized corrosion resistance of the passive layers generated on different tempers of AA7075 aluminium alloy.Cyclic potentiodynamic polarization has been employed to analyze the resistance to localized corrosion of the alloys in a chloride medium, whereas exfoliation corrosion susceptibility test (EXCO‐Test) have been performed to evaluate the influence of nitrogen implantation on exfoliation resistance.Results show that nitrogen implantation (dose of 2 × 1017 N+ ions/cm2 and energy of 50 keV) does not have a clear positive effect on exfoliation resistance as it is evident on EXCO testing. However, electrochemical experiments performed in 1 mM NaCl solution reveal a light increase on localized corrosion resistance on implanted alloys. Moreover, the results demonstrate that the susceptibility of the 7075 aluminium alloy to different types to localized corrosion such as, pitting, intergranular and exfoliation greatly depends on the aging treatment, even under implantation conditions. Copyright © 2010 John Wiley & Sons, Ltd.
Specifics of Hg‐based narrow gap semiconductor oxidation
Authors: Berchenko N. N. , Kurbanov K. , Fadeev S. V. 
Published: May 2010

AbstractThe composition of the oxide and oxide‐semiconductor interface of HgZnTe and HgMnTe alloys was analyzed by the method of equilibrium condensed phase diagrams, and experimentally studied by X‐ray diffractometry (XRD) and reflection high‐energy electron diffraction. It is concluded that in comparison with the HgCdTe‐oxide interface, at the HgZnTe‐oxide interface in addition to metallic Hg the liberation of elemental Te occurs, and MnTe2 with rich content of Te is liberated from the HgMnTe‐oxide interface. This explains the improvement in electrical properties of the anodic oxide structures and the thermal stability of MOS structures based on the sequence HgCdTe → HgMnTe → HgZnTe. Copyright © 2010 John Wiley & Sons, Ltd.
Formation and analysis of SiC coating layer on carbon short fiber
Authors: Lee C‐W. , Kim Il‐Ho , Lee Wonsik , Ko Se‐Hyun , Jang Jin‐Man , Lee T‐W. , Lim S‐H. , Park J. P. , Kim J. D. 
Published: May 2010

AbstractSiC‐coated carbon fibers for aluminum–carbon composites were synthesized with carbothermal reduction. For the SiC layer formation on the surface of carbon fiber, silica sol was coated and heat treated at a temperature of 1460 and 1500 °C. SiC layer formation by carbothermal reduction complete at above 1500 °C for 1 h. From TGA in atmosphere, SiC coating effectively protected against the oxidation of graphite. The thickness of the SiC coating layer ranged from 150 to 300 nm and the layer was formed homogenously along the surface of carbon fiber. As the first step of reaction for SiC formation, it is generally accepted that SiO is formed and vaporized in interface between fiber and silica. It is analogized in this work that the SiO vapor reacts directly with carbon fiber, resulting in formation of SiC phase. From the TEM results, the SiC layer was confirmed as a ZnS‐type FCC structure. Copyright © 2010 John Wiley & Sons, Ltd.
Comparison of electrical properties of HgCdTe subsurface layers formed by low energy ion beam milling or anodic oxidation
Authors: Berchenko N. , Izhnin I. , Yudenkov V. , Pociask M. , Yakovyna V. 
Published: May 2010

AbstractA comparative analysis has been carried out relating to p‐to‐n type conductivity conversion processes on vacancy and impurity‐ (As, Sb, Cu, Ag) doped p‐HgCdTe(x ≈ 0.2) using ion milling and anodic oxidation followed by thermal annealing. The conductivity type conversion has been observed in vacancy‐doped material either under ion milling or under anodic oxide annealing, while in the case of impurity doped material only under ion milling. It was demonstrated that in all these processes the conversion was determined by the mercury interstitial diffusion from the corresponding mercury diffusion source and recombination with its native acceptors–cationic vacancies, or by donor complex formations (As, Sb doping), or displacing Cu (Ag) from the cationic sublattice sites into interstitials. Absence of type conversion under anodic oxide annealing in impurity doped p‐HgCdTe is explained by insufficient Hg concentration in the source. The possibilities of changing the n‐layer properties by laser‐excited shock waves are discussed. Copyright © 2010 John Wiley & Sons, Ltd.
An XPS study on the influence of nitrogen implantation on the passive layers developed on different tempers of AA7075 aluminum alloy
Authors: Abreu C. M. , Cristóbal M. J. , Figueroa R. , Pena G. , Pérez M. C. 
Published: May 2010

AbstractThe present work analyzes the chemical effect of nitrogen implantation on the passive layer formed on different tempers of AA7075 aluminium alloy, T6 and T73. The experimental results from XPS depth profiles show that the air‐formed passive oxide, on both tempers, is mainly formed by Al2O3, highly hydrated, with Mg2+ and small amounts of Zn2+. The only difference between both tempers is the amount of Zn2+, significantly higher in T73‐temper and located in the outermost region of the passive oxide layer.Nitrogen implantation produces a modified layer containing a nitride phase, identified as AlN probably nanocrystalline, as the BE of N1s at 397.4 ± 0.2 eV indicates and GAXRD has confirmed. Moreover, nitrogen implantation changes the composition of the Al2O3 oxide by increasing the hydration content; no traces of Zn2+ are detected in its composition. Copyright © 2010 John Wiley & Sons, Ltd.
Efficient flow‐control algorithm cooperating with energy allocation scheme for solar‐powered WSNs
Authors: Noh Dong Kun , Abdelzaher Tarek F. 
Published: May 2010

AbstractRecently, solar energy emerged as a feasible supplement to battery power for wireless sensor networks (WSNs) which are expected to operate for long periods. Since solar energy can be harvested periodically and permanently, solar‐powered WSNs can use the energy more efficiently for various network‐wide performances than traditional battery‐based WSNs of which aim is mostly to minimize the energy consumption for extending the network lifetime. However, using solar power in WSNs requires a different energy management from battery‐based WSNs since solar power is a highly varying energy supply. Therefore, firstly we describe a time‐slot‐based energy allocation scheme to use the solar energy optimally, based on expectation model for harvested solar energy. Then, we propose a flow‐control algorithm to maximize the amount of data collected by the network, which cooperates with our energy allocation scheme. Our algorithms run on each node in a distributed manner using only local information of its neighbors, which is a suitable approach for scalable WSNs. We implement indoor and outdoor testbeds of solar‐powered WSN and demonstrate the efficiency of our approaches on them. Copyright © 2010 John Wiley & Sons, Ltd.
MIMO relay wireless networks with scheduling and transmit beamforming
Authors: Yang Liang 
Published: May 2010

AbstractIn this paper, we investigate the performance of a multiuser wireless relay network with each of its nodes equipped with N antennas and transmit beamforming at its source and relay, where multiuser diversity (MD) is exploited to further improve the system performance. In the first part of this paper, by deriving the approximate error performance expression for a single‐relay MD system without the direct link, we obtain the maximum diversity order achievable by the CSI‐assisted amplify‐and‐forward (CAF) protocol. Then, by taking the direct link into consideration, we propose a sub‐optimal transmit beamforming scheme and show the performance loss is very small. Copyright © 2010 John Wiley & Sons, Ltd.
Prevalence and determinants of suicide ideation among Lebanese adolescents: Results of the GSHS Lebanon 2005
Authors: Mahfoud Ziyad R. , Afifi Rema A. , Haddad Pascale H. , DeJong Jocelyn 
Published: May 2010

ABSTRACTThe current study examined prevalence and risk factors for suicide ideation in 5038 Lebanese adolescents using Global School Health Survey data. Around 16% of Lebanese adolescents thought of suicide. Multivariate logistic regression models showed that risk factors for suicide ideation included poor mental health (felt lonely, felt worried, felt sad or hopeless), substance use (got drunk, used drugs), victimization (was bullied, was sexually harassed), and lack of parental understanding. Recommendations for future research and interventions are discussed.