bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tunable nanopatterning by diblock copolymers in small confinements*
Authors: Rasmussen K. Ø. 
Published: September 2004

AbstractHere we study the effects of confinement on the self‐assembly of diblock copolymers. Specifically, we study the hexagonal cylindrical phase as it self‐assembles within a narrow confinement. We quantify the structural deformation of the cylindrical morphology that arises from the frustration that the narrow confinements exert on the system when the confinement width is incompatible with the lattice structure of the bulk mesophase. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3695–3700, 2004
Surface Analysis of Plasma‐Deposited Polymer Films, 1
Authors: Oran Umut , Swaraj Sufal , Friedrich Jörg F. , Unger Wolfgang E. S. 
Published: September 2004

AbstractSummary: Pulsed plasma‐deposited polystyrene films were studied by time‐of‐flight static secondary ion mass spectrometry (ToF‐SSIMS) before and after exposure to ambient air. The influence of the external plasma parameters on the secondary ion mass spectra of plasma‐deposited polystyrene films was investigated. From these data, information on the chemical character of the plasma polystyrene films was derived. In the range of deposition conditions applied in this study, the fragmentation of styrene is a minor process. The main process is probably the radical chain propagation to polymers. All the polystyrene plasma polymers, relying on ToF‐SIMS, seem to be rather similar to a reference polystyrene oligomer sample. When the plasma polymers are exposed to air, extensive oxygen incorporation occurs. Oxygen uptake was found to alter the emission probabilities of secondary ions. A relation between the regularity of the plasma polymers and the amount of oxygen incorporation was found. The result was that the chemical regularity of the plasma polystyrene decreases when the effective power in the plasma is increased.ToF‐SSIMS spectra of PP‐PS‐1 before exposure (left) and after two weeks exposure (right) to air. The intensity of the oxygen containing fragments increase indicating an increase on the amount of oxygen incorporation.magnified imageToF‐SSIMS spectra of PP‐PS‐1 before exposure (left) and after two weeks exposure (right) to air. The intensity of the oxygen containing fragments increase indicating an increase on the amount of oxygen incorporation.
Oxidative Degradation of Nitrophenols in Aqueous Solution Induced by Plasma with Submersed Glow Discharge Electrolysis
Authors: Gao Jinzhang , Pu Lumei , Yang Wu , Yu Jie , Li Yan 
Published: September 2004

AbstractSummary: The oxidative degradation of 4‐nitrophenol, 2,4‐dinitrophenol, and 2,4,6‐trinitrophenol in aqueous solution induced by plasma with submersed glow discharge has been investigated. The reaction intermediates were determined by high performance chromatography (HPLC). Various influencing factors such as the initial pH, the concentration of nitrophenols (NPs), and the catalytic action of Fe2+ were examined. The results indicate that the degradation pathways involve a slow opening of the aromatic ring followed by a rapid oxidation of the aliphatic compounds. The hydroxyl radicals are responsible for the primary attack of the NPs with formation of dihydroxynitrobenzenes. The attack of hydroxyl radical occurs at the ring positions activated by the presence of a phenolic OH group and a nitro group. The results suggested that the reaction obeyed a pseudo‐first order kinetic reaction and the proposed method is an efficient way for the nitrophenols degradation.Effect of pH on the degradation of 4‐nitrophenol.magnified imageEffect of pH on the degradation of 4‐nitrophenol.
Continuous and Modulated Deposition of Fluorocarbon Films from c‐C4F8 Plasmas
Authors: Milella Antonella , Palumbo Fabio , Favia Pietro , Cicala Grazia , d'Agostino Riccardo 
Published: September 2004

AbstractSummary: Continuous and modulated c‐C4F8 (perfluorocyclobutane) plasmas were used to deposit thin Teflon‐like films. Gas phase and film composition and structure were investigated and the results can be rationalized with the deposition mechanism developed in a previous work for C2F4‐modulated plasmas. The effect of modulation on the morphology and the chemistry of the surface were studied.CFx percentages as a function of the duty cycle for films deposited for 90 min from modulated discharges sustained at 100 W, 300 mtorr, and 6 sccm.magnified imageCFx percentages as a function of the duty cycle for films deposited for 90 min from modulated discharges sustained at 100 W, 300 mtorr, and 6 sccm.
Rock‐wall temperatures in the Alps: modelling their topographic distribution and regional differences
Authors: Gruber Stephan , Hoelzle Martin , Haeberli Wilfried 
Published: September 2004

AbstractRising temperatures or the complete thaw of permafrost in rock walls can affect their stability. Present as well as projected future atmospheric warming results in permafrost degradation and, as a consequence, makes knowledge of the spatial distribution and the temporal evolution of rock temperatures important. Rock‐face near‐surface temperatures have been measured over one year at 14 locations between 2500 and 4500 m a.s.l. in the Alps. Different slope aspects have been included in order to capture the maximum spatial differentiation of rock temperatures. These data were used to further develop and verify an energy‐balance model that simulates daily surface temperatures over complex topography. Based on a 21‐year (1982–2002) run of this model, spatial patterns of rock‐face temperatures in the Swiss Alps are presented and discussed. This model provides a basis for the re‐analysis of past rock‐fall events with respect to permafrost degradation as well as for the simulation of future trends of rock temperatures. Furthermore, the spatial patterns of rock‐wall temperatures provide a quantitative insight into the topography‐related mechanisms affecting permafrost distribution in Alpine areas without local influence from snow cover or an active layer with a complex thermal offset. Copyright © 2004 John Wiley & Sons, Ltd.
Effect of deep inspiration on airway caliber in children with asthma
Authors: Assefa Dagnachew , Amin Nikhil , Dozor Allen J. 
Published: September 2004

AbstractThe objective of this study was to assess the effect of deep inspiration (DI) on airway caliber in school‐age children with asthma. Thirty children with asthma (10 from each group of mild, moderate, and severe persistent asthma as defined by the National Asthma Education and Prevention Program guidelines of the National Heart, Lung, and Blood Institute) were enrolled, and their results were compared to those obtained in 7 healthy children. Subjects performed a partial expiratory flow volume curve (P) initiated from ∼70% of vital capacity (VC) followed by a maximal expiratory flow volume (M) maneuver begun from total lung capacity (TLC). The M/P ratio at 30% of the VC (M/P30) was calculated. Specific airway conductance (sGaw) was measured before and immediately after DI, using standard techniques. Differences in M/P30 and sGaw ratios between asthma and control groups were compared with Student's unpaired t‐tests. One‐way ANOVA was used to compare the effect of DI on M/P30 and sGaw ratios among the various asthma severity groups. The M/P30 ratio (mean ± 1 SD) was significantly lower in children with moderate and severe persistent asthma (0.73 ± 0.21 and 0.72 ± 0.1, respectively) than in healthy controls (1.69 ± 0.62) (P < 0.05). In mild persistent asthmatics, there was limited bronchodilation (M/P30 = 1.1 ± 0.35, P = 0.052). There was a significant inverse correlation between M/P30 ratio and severity of asthma (r = −0.684, P < 0.01). The mean sGaw ratio was decreased in asthmatic subjects compared to healthy controls (0.98 ± 0.17 vs. 1.13 ± 0.16, P = 0.062). In conclusion, in school‐age children, the effects of DI on airway caliber are similar in direction to those observed in adults, i.e., bronchodilation in healthy and mild asthmatics, and bronchoconstriction (BC) in moderate to severe asthmatics. This finding suggests that forces that determine airway caliber in school‐age children are similar to those forces in adults. © 2004 Wiley‐Liss, Inc.
Influence of organic carbon on reductive dechlorination of thiobencarb in California rice field soils
Authors: Schmelzer Kara R , Johnson Catherine S , Viant Mark R , Williams John F , Tjeerdema Ronald S 
Published: September 2004

AbstractThe herbicide thiobencarb is suspected of causing delayed phytotoxicity syndrome (DPS) in rice plants. While the ultimate agent appears to be its dechlorinated product (deschlorothiobencarb), the influence of organic carbon on the formation of deschlorothiobencarb in California rice field soils has not been investigated. Thus, two different soils were compared for their ability to reductively dechlorinate thiobencarb with carbon augmentation: one from the eastern Sacramento Valley, which has historically displayed DPS, and one from the western Sacramento Valley, which has not. Rice straw was homogenized into samples of each soil to produce 0, 0.33 or 2% organic carbon augmentation. During 90‐days of anoxic incubation, substantial deschlorothiobencarb production was measured in both soil types. However, only the thiobencarb degradation rate in the eastern valley soil was positively correlated with carbon content. Thus, other characteristics of DPS‐resistant soils may limit deschlorothiobencarb formation. Copyright © 2004 Society of Chemical Industry
White light emitting silicon nanocrystals as nanophosphor
Authors: Lee Soojin , Cho Woon Jo , Han Il Ki , Choi Won Jun , Lee Jung Il 
Published: September 2004

AbstractWe exploited the practical sonochemical route for preparing silicon nanocrystals at room temperature and ambient pressure. This synthesis provided the very fast reaction within a few hours and the useful modification for the surface of silicon nanoparticles. The average size of prepared nanocrystals was 2.8 nm and confirmed by TEM images. The chlorine‐capped nanoparticles were characterized by FT‐IR spectroscopy. The luminescence of silicon colloid was observed in the wide range between 340 nm and near 700 nm and showed white color with commercial low‐intensity UV‐lamp exposure. This synthetic strategy is potentially applicable for illuminating devices such as white light emitting diodes. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Properties of the fundamental absorption edge of InN crystals investigated by optical reflection and transmission spectra
Authors: Ishitani Y. , Xu K. , Che S. B. , Masuyama H. , Terashima W. , Yoshitani M. , Hashimoto N. , Akasaka K. , Ohkubo T. , Yoshikawa A. 
Published: September 2004

AbstractInN crystals are grown on sapphire substrates using a plasma‐assisted MBE system. The carrier concentrations of the samples are 2 × 1018–1 × 1019 cm–3. Optical transmission and reflectance measurements are performed on these samples in the temperature range 5–300 K. The resultant spectra are analysed by theoretical spectra based on the LO‐phonon–plasmon coupling scheme for the phonon‐related factor and non‐parabolic conduction band structure for the electronic transition factor. The observed absorption edge is estimated to originate from a valence band to conduction band transition rather than a defect‐ or impurity‐related transition. It is estimated that InN has a bandgap energy in the range 0.59–0.65 eV. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Joint ―X and R Charts with Two‐stage Samplings
Authors: Costa Antonio F. B. , Rahim M. A. 
Published: September 2004

AbstractWhen joint ―X and R charts are in use, samples of fixed size are regularly taken from the process, and their means and ranges are plotted on the ―X and R charts, respectively. In this article, joint ―X and R charts have been used for monitoring continuous production processes. The sampling is performed, in two stages. During the first stage, one item of the sample is inspected and, depending on the result, the sampling is interrupted if the process is found to be in control; otherwise, it goes on to the second stage, where the remaining sample items are inspected. The two‐stage sampling procedure speeds up the detection of process disturbances. The proposed joint ―X and R charts are easier to administer and are more efficient than the joint ―X and R charts with variable sample size where the quality characteristic of interest can be evaluated either by attribute or variable. Copyright © 2004 John Wiley & Sons, Ltd.
Nonlinear generalization of scaled ℋ︁∞control: global robustification against nonlinearly bounded uncertainties
Authors: Ito Hiroshi 
Published: September 2004

AbstractThis paper proposes a novel approach to the problem of ℒ︁2disturbance attenuation with global stability for nonlinear uncertain systems by placing great emphasis on seamless integration of linear and nonlinear controllers. This paper develops a new concept of state‐dependent scaling adapted todynamicuncertainties andnonlinear‐gain boundeduncertainties that do not necessarily have finite linear‐gain, which is a key advance from previous scaling techniques. The proposed formulation of designing global nonlinear controllers is not only a natural extension of linear robust control, but also the approach renders the nonlinear controller identical with the linear control at the equilibrium. This paper particularly focuses on scaled ℋ︁∞control which is widely accepted as a powerful methodology in linear robust control, and extends it nonlinearly. If the nonlinear system belongs to a generalized class of triangular systems allowing for unmodelled dynamics, the effect of the disturbance can be attenuated to an arbitrarily small level with global asymptotic stability by partial‐state feedback control. A procedure of designing such controllers is described in the form of recursive selection of state‐dependent scaling factors. Copyright © 2004 John Wiley & Sons, Ltd.
Multi‐objective learning control for robotic manipulator
Authors: Win Khin Kyu Kyu , Cheah Chien‐Chern 
Published: September 2004

AbstractSeveral types of learning controllers have been proposed in the literature to improve the tracking performance of robot manipulators. In most cases, the learning algorithms emphasize mainly on a single objective of learning a desired motion of the end‐effector. In some applications, more than one objective may be specified at the same time. For example, a robot may be required to follow a desired trajectory (primary objective) and at the same time avoid an obstacle (secondary objective). Thus, multi‐objective learning control can be more effective to realize the collision‐free tasks. In this paper, a multi‐objective learning control problem is formulated and solved. In the proposed learning control system, the primary objective is to track a desired end‐effector's motion and several secondary objectives can be specified for the desired orientation and for obstacles avoidance. To avoid obstacles in the workspace, a new learning concept called “region learning control” is also proposed in this paper. The proposed learning controllers do not require the exact knowledge of robot kinematics and dynamics. Sufficient condition is presented to guarantee the convergence of the learning system. The proposed learning controllers are applied to a four‐link planar redundant manipulator and simulation results are presented to illustrate the performance. © 2004 Wiley Periodicals, Inc.
Self‐assembly of stearic acid on aluminium: the importance of oxide surface chemistry
Authors: Pertays K. M. , Thompson G. E. , Alexander M. R. 
Published: September 2004

AbstractThe influence of ambient atmospheric exposure on the chemistry of the magnetron‐sputtered aluminium surface has been characterized as hydroxyl incorporation to the oxide surface and concurrent adsorption of airborne carbonaceous contamination. Here, the consequence of these changes in oxide surface chemistry upon the adsorption of stearic acid from solution is investigated. Water contact angle and polarization modulation infrared refection–absorption spectroscopy (PM‐IRRAS) reveal a strong dependence of stearic acid monolayer order upon ambient exposure time prior to assembly. It is proposed that hydroxyl formation in the ambient atmosphere increases the stearic acid adsorption density and thus the self‐assembled monolayer (SAM) order, whereas airborne carbonaceous material blocks these adsorption sites and introduces disorder in the monolayers through a decrease in adsorption density.Monolayer adsorption has been correlated with the aluminium oxide surface chemistry. It is proposed that this phenomenon represents an explanation for the irreproducible results often reported for assembly on metal oxide substrates. Furthermore, it indicates that in this broad class of material surfaces assembly can be used as a means of estimating the reactivity of surfaces with respect to organic overlayers such as paints and adhesives. Removal of adsorbed carbonaceous material from the aluminium surface using an oxygen plasma resulted in a significantly increased order of the stearic acid monolayer, as assessed by water contact angle. This observation is rationalized as the removal of carbonaceous material blocking surface adsorption sites by the plasma, but retention of the underlying hydroxyl functionality. This is predicted to have important implications in the preparation of aluminium for painting and adhesive bonding. Copyright © 2004 John Wiley & Sons, Ltd.
Neue Messe Mailand – Netzstruktur und Tragverhalten einer Freiformfläche
Authors: Schober Hans , Kürschner Kai , Jungjohann Hauke 
Published: September 2004

AbstractDie Verbindungswege zwischen den einzelnen Bereichen der neuen Messe Mailand werden größtenteils durch architektonisch sehr reizvolle Stahl‐Glas‐Konstruktionen überdeckt. Am Haupteingang entsteht das ‘Logo’: eine zweiachsig gekrümmte Freiformfläche, die mit ca. 37 m wie ein Vulkan in die Höhe ragt und somit bereits von der Ferne als Wahrzeichen zu erkennen sein wird. Ein 1300 m langes und 30 m breites freigeformtes Glasdach, das sog. ‘Vela’, erschließt in der Hauptachse der Messe die einzelnen Hallen und nimmt sich die in Sichtweite befindlichen Alpen in seiner Formgebung wieder auf. Insbesondere am Beispiel des ‘Logo’ beschreibt der Beitrag neben der allgemeinen Entwurfsidee schwerpunktmäßig die Prinzipien zur Ermittlung der Netzgeometrie und die Besonderheiten der Tragstruktur der beliebig gekrümmten Freiformflächen.
Ermittlung der Grenztragfähigkeit von Mehrschraubenverbindungen bei Normalkraft‐Biegemoment‐Interaktion
Authors: Stephan Sören , Stutzki Christian 
Published: September 2004

AbstractDieser Aufsatz beschreibt eine zur Anwendung in Computerprogrammen geeignete, allgemeine Methode zur Bemessung von Ein‐ und Mehrschraubenverbindungen von Stäben mit beliebigen dünnwandigen Querschnitten. Diese Methode basiert auf dem klassischen Verfahren der Dehnungsiteration zur Ermittlung der Spannungsverteilung in Querschnitten. Die Grenztragfähigkeit der Schraubenverbindung wird hierbei auf der Grundlage einer iterativen numerischen Bestimmung der elastisch‐plastischen Spannungsverteilung in den Anschlußelementen ermittelt. Die Berechnungsmethode wird in zwei Schritten entwickelt – zuerst wird die numerische Bestimmung der Spannungsverteilung für eine gegebene Schnittgrößenkombinationen gezeigt und danach wird die Bestimmung der Grenztragfähigkeit der Schraubenverbindung dargestellt. Weiterhin wird ein analytisches Verfahren zur Bemessung von Mehrschrauben‐Rundrohrverbindungen hergeleitet. Schließlich werden die Ergebnisse der numerischen und analytischen Berechnungen mit entsprechenden Versuchsergebnissen verglichen.
Einbauteile unter Querkraft‐ und Biegemomentenbeanspruchung
Authors: Ritscher Dieter , Osterland Kay 
Published: September 2004

AbstractDer Beitrag beschreibt im ersten Teil die theoretischen Grundlagen der Lasteinleitung von in Beton eingespannten Stahlstäben zur Aufnahme von Querkräften und Biegemomenten bei Einhaltung der zulässige Pressung im Beton. Ziel der Überlegung ist der Verzicht auf Schubpratzen, die z. B. bei einer Untermörtelung der Fußplatte schwer oder gar nicht realisierbar sind. Im zweiten Teil wird die Einleitung der Querkraft aus Einbauplatten über angeschweißte Schubbolzen anstelle der üblichen Schubpratzen behandelt. Einbauplatten mit kleinformatigen Schubbolzen sind leicht in die Bewehrung einbaubar und benötigen meist keine speziellen Aussparungen.
Starch Modification, Destructuration and Hydrolysis during O‐Formylation
Authors: Divers Thomas , Pillin Isabelle , Feller Jean‐François , Levesque Guy , Grohens Yves 
Published: September 2004

AbstractThe mixing of dry starch with 40 or 99% (v/v) formic acid (FA) produces an O‐formylation reaction which causes a combination of acid hydrolysis and starch destructuration. Moreover, this esterification reaction is highly exothermic in the presence of pure FA. When O‐formylation is performed at temperatures higher than 20°C, starch formate content is high (degree of substitution, DS, of 2.15 after 60 min at 105°C) but then molecular weight decreases (ηred ≶ 10 mL/g). Under thermally‐controlled conditions at 20°C in formic acid, degrees of substitution reach 1.5–1.6 after 6 h reaction times and polymer degradation seems to be limited (ηred = 110 to 140 mL/g). The degrees of substitution obtained in water/formic acid mixtures are below those in formic acid alone. The level of destructuration of starch in formic acid and water/formic acid mixtures was also evidenced by dynamic rheological measurements and optical microscopy. Plots of storage modulus (G’) versus frequency (ω) was used to characterize both the gelatinization and the gel destruction processes as a function of reaction temperature (Tr) and FA concentration.
Impact of Annealing on the Physicochemical Properties of Unfermented Cassava Starch (“Polvilho Doce”)
Authors: Gomes Anida M. M. , da Silva Claudio E. Mendes , Ricardo Nágila M. P. S. , Sasaki José M. , Germani Rogério 
Published: September 2004

AbstractUnfermented cassava starch (“polvilho doce”) was subject to annealing treatment at 50°C for 24, 48, 96, 120, 168 and 192 h, in 1:5 starch to water ratio. The annealing treatment changed the internal structure of “polvilho doce” at increasing treatment time. Peak viscosities decreased significantly, denoting that there was a decrease in leaching of amylose from the granules. The pasting temperatures were increased, setback and breakdown were reduced while hold and final viscosities increased, showing an improvement of the stability of the paste. Swelling power and solubility were reduced at all temperatures and the solubility at 55°C was zero after 120 h of treatment. The DSC data for To, Tp, Tc and ΔH increased and the gelatinization range was narrowed. The X‐ray diffractograms changed from CA to A pattern (samples annealed for 48, 96, 120, 168 and 192 h), denoting an increase in organization of double helices of amylopectin. Annealing imparts to the samples some waxy starches characteristics which can be very useful in the food industry.