bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Composite, Gel-Type Proton Membranes
Authors: Scrosati Bruno , Navarra Maria Assunta , Fernicola Alessandra , Panero Stefania 
Published: November 2006

This paper reviews the properties of a new microporous, composite proton conducting gel membrane, formed by swelling with aqueous acid solutions suitable polymer matrices	matrices containing a dispersed ceramic fillers. The data reported show that these membranes have a high and stable conductivity, a proton transport not critically influenced by the relative humidity level and a projected very low cost. Tests in a hydrogen-air laboratory cell also demonstrate that the membranes are basically suitable for application in polymer electrolyte fuel cells.
Spectroscopic Studies of Heteropoly Acid-doped 3M Perfluorinated Sulfonic Acid Polymer Membranes
Authors: Herring Andrew M. , Meng Fanqin , Frey Matthew , Hamrock Steve , Turner John , Dec Steve , Williamson Don 
Published: November 2006

3M PFSA ionomer membranes were doped with heteropoly acids (HPA) and the ionomer/HPA interaction characterized by attenuated total reflection FTIR, pulse field gradient spin echo NMR and small-angle X-ray scattering. The HPA doping was achieved by casting a mixed solution containing both components. Three Keggin-type HPAs were used in this work: 12- phosphotungstic acid, 12-silicotungstic acid, and 12- zincotungstic acid, at doping concentrations of 1 and 5wt %, respectively. FTIR spectra of the composite membranes clearly show the presence of the HPA and evidence for different interactions under different hydration states.	Proton diffusion coefficients were determined by PFGSE NMR under dry and 100 % RH from room temperature to 130 {degree sign}C. SAXS patterns of the control PFSA and the HPA-doped PFSA membranes were recorded under dry and wet conditions. Scattering behavior for different samples and conditions are remarkably different, consistent with the incorporation of HPA and the swelling of the ionomer clusters under hydration.
Design and Development of a Novel Flow Field for PEM Fuel Cells to Obtain Uniform Flow Distribution
Authors: Debe Mark K. , Herdtle Thomas 
Published: November 2006

A new flow field design concept was discovered, based on the close coupling of the flow field geometry and gas transport through the MEA diffusion current collector component's in- plane permeability. The new flow field offers significant gain in uniformity of reactant distributions within PEM fuel cells.	Computational fluid dynamic simulations of the two dimensional gas flow velocities over the MEA active areas are used to demonstrate the improvement in mass flow uniformity with the new design compared to more conventional flow field types. A math analysis based on Darcy's law applied to the new flow field design concept provided the basis for a quantitative estimate of how the effect depended on geometry, and further improvements to be made which compensate for down-the-channel consumption of reactants for any given stoichiometry. Experimental tests with version 1.0 of the new flow field design are discussed.
Consumption of Pt Catalyst under Electrolysis and Fuel Cell Operation
Authors: Kawahara Shuya , Mitsushima Shigenori , Ota Ken-Ichiro , Kamiya Nobuyuki 
Published: November 2006

The relationship between the charge transfer of Pt dissolution reaction and the consumption has been investigated to clarify the dissolution mechanisms. It was determined using both the symmetric and asymmetric waves of potential. The charge of Pt oxidation was always larger than that of reduction. The difference of the oxidation and the reduction charges should be caused by the dissolution of Pt. From the relationship between the difference of the charges and the amount of the consumption, the electron number of Pt dissolution reaction was ca. 4. Therefore, the dissolution mechanism under the symmetric wave and asymmetric waves of the slow anodic / the fast cathodic sweep would be Pt → Pt4+ + 4e-. Pt consumption under asymmetric waves of the fast anodic / the slow cathodic sweep was enhanced, and this reaction would be PtO2 + 4H+ + 2e- → Pt2+ + 2H2O.	The dissolved Pt2+ was detected with the RRDE measurement.
Effect of Relative Humidity on Membrane Durability in PEM Fuel Cells
Authors: Liu Wen , Cleghorn S. 
Published: November 2006

A series of steady state life tests were conducted in order to better understand the influence of relative humidity on membrane durability in PEM fuel cells.	It was discovered that under-saturated outlet conditions resulted in much longer membrane life and lower fluoride release rate from the membrane, as compared with over-saturated outlet conditions. Under such favorable conditions, ePTFE reinforced GORE-SELECT® membranes using perfluorinated sulfonic acid (PFSA) ionomer have demonstrated over 5,000 hours life at 95 ºC cell temperature, and over 2,500 hours life at 110 ºC. The impact of concentration of metal ions was studied by life testing MEAs containing membranes with different levels of Fe2+. It was hypothesized that under-saturated outlet conditions may prevent contaminants such as metal ions from entering the membrane, therefore, resulting in less chemical attack of the ionomer, and leading to longer membrane life.
Factors Impacting Chemical Degradation Of Perfluorinated Sulfonic Acid Ionomers
Authors: Liu Han , Gasteiger H. A. , Laconti Anthony , Zhang Jingxin 
Published: November 2006

Several factors impacting chemical degradation of perfluorinated sulfonic acid ionomers are identified in this paper.	Based on the results from this study, gas crossover is the fundamental mechanism that leads to PFSA membrane chemical degradation. H2, O2 and a catalytic surface are required to generate H2O2/radicals. The effect of electrochemically generated Pt oxide/hydroxide, Vulcan® XC-72R, Pt/C is clarified. Two major degradation pathways, H2O2 Pathway and Direct Radical Generation Pathway, are proposed. The impact of iron contamination and H2O2 concentration is also discussed. It was shown that a H2O2 flow cell is a better approach for membrane/MEA evaluation than conventional beaker based Fenton's tests (i.e., batch-like tests).
Rotating Rate Dependency of Methanol Oxidation on a Smooth Polycrystalline Platinum Surface
Authors: Hou Guoyan , Prakash J. 
Published: November 2006

Methanol adsorption and oxidation on platinum based catalysts have been extensively studied on well-characterized single crystal Pt, polycrystalline Pt, PtRu alloys, as well as high surface area catalysts. However, the quantitative kinetic and mechanistic studies using hydrodynamic techniques such as rotating disk electrode (RDE) or rotating ring-disk electrodes (RRDE) have been severely limited , , .	The aim of this study was to examine the kinetics of methanol oxidation on a polycrystalline platinum rotating disc electrode in an acidic solution. The experiments were carried out in a conventional electrochemical cell. The electrolyte consisted of a solution of approximately 1M, de-oxygenated methanol and 0.5MH2SO4 at room temperature. The rotating disk electrode (RDE) measurements for the methanol oxidation on the Pt disk electrode were obtained at various rotation rates. Polarization curves obtained with the RDE measurements indicate that the kinetics and mechanism of the methanol oxidation are potential dependent. A mass transport corrected Tafel slope of 125 mV/decade was found on the relatively oxide free surface and is indicative of the first electron transfer as the rate determining step.
Injection of Hydrogen and Vacancy-Type Defects during Dissolution of Aluminum
Authors: Hebert K. R. , Adhikari Saikat , Lee Jinju , Chen Hongmin , Jean Y. C. 
Published: November 2006

Formation of interfacial nanoscale voids in Al during room-temperature caustic corrosion was characterized by positron annihilation spectroscopy (PAS) and compared with measurements of deuterium absorption using secondary ion mass spectrometry (SIMS). The hypothesis was investigated that voids are created from vacancy-hydrogen (Vac-H) defects introduced during corrosion. Evidence for both mobile and immobile forms of absorbed hydrogen was obtained, the latter present within distances of 50 nm from the metal-oxide interface, where voids were also found. During corrosion, the immobile hydrogen was found only during discrete 1-2 min intervals of time separated by periods of 1-2 min when it was not present.	Model calculations suggested that this transient behavior is consistent with repeated nucleation and dissolution of clusters of Vac-H defects. Only some aspects of the time-dependence of the void concentration from PAS corresponded with that of absorbed hydrogen; the former is believed to be influenced by metallic impurities.
MO Simulation of Surface Diffusion of Zinc Adatoms on Zinc Surface
Authors: Azumi Kazuhisa , Iokibe Kei , Seo Masahiro 
Published: November 2006

Surface diffusion process of zinc adatoms on zinc crystal surface was simulated using semi-empirical molecular orbital (MO) method. Total energy, ET, of molecular orbitals belong to the system including adatom and surface atoms was calculated for two surface models; one is a small cluster composed from surface atoms and another is periodically repeated arrangement of surface atoms. ET was calculated as a function of position of adatom on the terrace, near the step and kink sites to draw energy contour map.	From the energy map migration path of adatom on the surface and their activation energy for diffusion, ED, were estimated. From these results adequacy of terrace-step-kink (TSK) model for epitaxial growth was confirmed. Formation of deposition island and effect of water molecular on the surface are also discussed.
The Effect of Tungsten Addition to the Intermediate IrO2 Layer of Mn-Mo-O/IrO2/Ti Electrodes on the Performance for Oxygen Evolution in Seawater Electrolysis
Authors: Kato Zenta , Kumagai Naokazu , Asami Katsuhiko , Hashimoto Koji 
Published: November 2006

Oxygen evolution even in seawater electrolysis for hydrogen production can be done by using the electrodes consisting of the outer electrocatalytically active Mn1-xMoxO2+x layer, the intermediate iridium dioxide layer and the titanium substrate.	An attempt was made to decrease the use of iridium in the intermediate layer which is necessary to avoid the growth of insulating titanium oxide on the titanium substrate during anodic deposition of the Mn1-xMoxO2+x layer and during seawater electrolysis. The addition of tungsten to the intermediate layer, the oxide of which is stable under anodic polarization in addition to high activity for oxygen evolution and very low activity for chlorine evolution in seawater electrolysis, was effective to decrease the use of iridium to 1/5.
Evaluation of Time Constants Governing the Cathodic Reaction in SOFCs
Authors: Smith Jeremiah R. , Orazem Mark , Duncan Keith , Chen Aijie , Wachsman E. D. 
Published: November 2006

The need for power sources has created a lot of interest in fuel cells.	SOFCs with LSM and LSCF cathodes and YSZ electrolytes are materials of interest; however, the processes governing the cathodic reactions are not well understood. Impedance spectroscopy is used to evaluate the RC time constant behavior of the various electrochemical steps contributing to the cathodic reaction. This evaluation typically involves separating the various contributions using a circuit element type model. The focus of this work is to use the model parameters to determine kinetic behavior, particularly the time constants for each of the process steps contributing to the overall cathodic reaction. The determined time constants are compared for the various cathode materials tested with the goal of generating a common understanding of the kinetic behavior of the cathodic SOFC reaction.
The Evolution of Surface Roughness of Copper Electrodeposition Directly on Ultra-Thin Air Exposed TaN Layers
Authors: Lay Nicole , Duquette David 
Published: November 2006

Surface roughness of both seed layers and electrodeposited copper for ULSI interconnects affect adhesion and fracture characteristics of the electrodeposited plate.	In this program experiments were performed on copper, deposited from complexing citrate baths, directly onto TaN barrier layers, as a function of copper thickness (as measured by plating time) and subsequent annealing. It has been shown that surface roughness increase with increasing plate thickness, reaching a constant roughness at a thickness of about 350 nm. Annealing, in order to enhance plate resistivity, has no appreciable effect on surface roughness.
Development of Electrochemical Mechanical Polishing for Advanced Copper Planarization
Authors: Jia Renhe , Wang You , Wang Zhihong , Tsai Stan , Diao Jie , Mao Daxin , Karuppiah Laksh , Chen Liang-Yuh 
Published: November 2006

Incorporation of low-k materials in advanced metallization calls for novel planarization technology to avoid delamination and improve defect performance. Electrochemical mechanical polishing (EcmpTM) uses electrical voltage as the main driving force for Cu removal, enabling low down force operation that is needed when polish fragile low-k materials. Previously reported Ecmp results discussed the bulk Cu removal step. We now have developed the Ecmp process on the Cu residue clearance step. Therefore, low down force can be applied during the entire Cu removal process, as required when the industry moves to low-k dielectric materials. In addition, due to specific formulation of the consumables used in the process, Ecmp will lead to reduced dishing and erosion, as well as improved surface finish. This paper is focused on the copper clearance step. Chemistry development is key for Ecmp to reduce dishing and maintain good surface finish. The basic principle of Ecmp and the behaviors of some electrolyte will be discussed.	It was found that the dishing performance is closely related to the pH of the electrolyte used.
Anatomical Substrates of Visual and Auditory Miniature Second-language Learning
Authors: Newman-Norlund Roger D. , Frey Scott H. , Petitto Laura-Ann , Grafton Scott T. 
Published: November 2006

Abstract
Longitudinal changes in brain activity during second language (L2) acquisition of a miniature finite-state grammar, named Wernickese, were identified with functional magnetic resonance imaging (fMRI). Participants learned either a visual sign language form or an auditory-verbal form to equivalent proficiency levels. Brain activity during sentence comprehension while hearing/viewing stimuli was assessed at low, medium, and high levels of proficiency in three separate fMRI sessions. Activation in the left inferior frontal gyrus (Broca's area) correlated positively with improving L2 proficiency, whereas activity in the right-hemisphere (RH) homologue was negatively correlated for both auditory and visual forms of the language. Activity in sequence learning areas including the premotor cortex and putamen also correlated with L2 proficiency. Modality-specific differences in the blood oxygenation level-dependent signal accompanying L2 acquisition were localized to the planum temporale (PT). Participants learning the auditory form exhibited decreasing reliance on bilateral PT sites across sessions. In the visual form, bilateral PT sites increased in activity between Session 1 and Session 2, then decreased in left PT activity from Session 2 to Session 3. Comparison of L2 laterality (as compared to L1 laterality) in auditory and visual groups failed to demonstrate greater RH lateralization for the visual versus auditory L2. These data establish a common role for Broca's area in language acquisition irrespective of the perceptual form of the language and suggest that L2s are processed similar to first languages even when learned after the “critical period.” The right frontal cortex was not preferentially recruited by visual language after accounting for phonetic/structural complexity and performance.
The Impact of Proficiency on Syntactic Second-language Processing of German and Italian: Evidence from Event-related Potentials
Authors: Rossi Sonja , Gugler Manfred F. , Friederici Angela D. , Hahne Anja 
Published: November 2006

AbstractThe present study investigated the role of proficiency in late second-language (L2) processing using comparable stimuli in German and Italian. Both sets of stimuli consisted of simple active sentences including a word category violation, a morphosyntactic agreement violation, or a combination of the two. Four experiments were conducted to study high- and low-proficiency L2 learners of German as well as high- and low-proficiency L2 learners of Italian. High-proficiency L2 learners in both languages showed the same event-related potential (ERP) components as native speakers for all syntactic violations. For the word category violation, they displayed an early anterior negativity (ELAN), an additional negativity reflecting reference-related processes, and a late P600 evidencing processes of reanalysis. For the processing of the morphosyntactic error, an anterior negativity (LAN) and a P600 were observed, whereas for the combined violation, the same ERP components were found as in the pure category violation. In high-proficiency L2 learners, the timing of the processing steps was equivalent to that of native speakers, although some amplitude differences were present. Low-proficiency L2 learners, however, showed qualitative differences in the agreement violation characterized by the absence of the LAN and quantitative differences reflected in a delayed P600 in every violation condition. These findings emphasize that with a high proficiency, late L2 learners can indeed show native-like neural responses with the timing approximating that of native speakers. This challenges the idea that there are fundamental differences in language processing in the brain between natives and late L2 learners.
Time Course of Brain Activity during Change Blindness and Change Awareness: Performance is Predicted by Neural Events before Change Onset
Authors: Pourtois Gilles , De Pretto Michael , Hauert Claude-Alain , Vuilleumier Patrik 
Published: November 2006

Abstract
People often remain “blind” to visual changes occurring during a brief interruption of the display. The processing stages responsible for such failure remain unresolved. We used event-related potentials to determine the time course of brain activity during conscious change detection versus change blindness. Participants saw two successive visual displays, each with two faces, and reported whether one of the faces changed between the first and second displays. Relative to blindness, change detection was associated with a distinct pattern of neural activity at several successive processing stages, including an enhanced occipital P1 response and a sustained frontal activity (CNV-like potential) after the first display, before the change itself. The amplitude of the N170 and P3 responses after the second visual display were also modulated by awareness of the face change. Furthermore, a unique topography of event-related potential activity was observed during correct change and correct no-change reports, but not during blindness, with a recurrent time course in the stimulus sequence and simultaneous sources in the parietal and temporo-occipital cortex. These results indicate that awareness of visual changes may depend on the attentional state subserved by coordinated neural activity in a distributed network, before the onset of the change itself.
When Gaze Turns into Grasp
Authors: Pierno Andrea C. , Becchio Cristina , Wall Matthew B. , Smith Andrew T. , Turella Luca , Castiello Umberto 
Published: November 2006

Abstract
Previous research has provided evidence for a neural system underlying the observation of another person's hand actions. Is the neural system involved in this capacity also important in inferring another person's motor intentions toward an object from their eye gaze? In real-life situations, humans use eye movements to catch and direct the attention of others, often without any accompanying hand movements or speech. In an event-related functional magnetic resonance imaging study, subjects observed videos showing a human model either grasping a target object (grasping condition) or simply gazing (gaze condition) at the same object. These two conditions were contrasted with each other and against a control condition in which the human model was standing behind the object without performing any gazing or grasping action. The results revealed activations within the dorsal premotor cortex, the inferior frontal gyrus, the inferior parietal lobule, and the superior temporal sulcus in both “grasping” and “gaze” conditions. These findings suggest that signaling the presence of an object through gaze elicits in an observer a similar neural response to that elicited by the observation of a reach-to-grasp action performed on the same object.
Precursors of Insight in Event-related Brain Potentials
Authors: Lang Simone , Kanngieser Nadine , Jaśkowski Piotr , Haider Hilde , Rose Michael , Verleger Rolf 
Published: November 2006

Abstract
Event-related potentials (ERPs) were investigated to find precursors of insightful behavior. Participants had to process successive pairs in strings of digits to obtain a final response in each trial. Within the sequence of five responses required in each trial, the last two responses mirrored the two preceding ones. This hidden regularity, allowing for shortcutting each trial from five to two responses, was discovered by 6 out of 26 participants. Both groups, solvers and nonsolvers, implicitly learned the regularity, reflected by faster responses to the repeated, predictable responses, but this differential effect was larger in solvers, whereas nonsolvers became unspecifically faster with all responses. Several ERP components were larger in solvers than in nonsolvers from the outset: slow positive wave, frontocentral P3a, anterior N1 to those digits that triggered the critical repeating responses, and P3b to the digit that evoked the immediately repeating response. Being already present in the first block, these effects were early precursors of insightful behavior. This early occurrence suggests that participants who will gain insight may be distinguished beforehand by their individual characteristics.
A Daytime Complement to the Reverse Absorption Technique for Improved Automated Detection of Volcanic Ash
Authors: Pavolonis Michael J. , Feltz Wayne F. , Heidinger Andrew K. , Gallina Gregory M. 
Published: November 2006

Abstract
An automated volcanic cloud detection algorithm that utilizes four spectral channels (0.65, 3.75, 11, and 12 μm) that are common among several satellite-based instruments is presented. The new algorithm is physically based and globally applicable and can provide quick information on the horizontal location of volcanic clouds that can be used to improve real-time ash hazard assessments. It can also provide needed input into volcanic cloud optical depth and particle size retrieval algorithms, the products of which can help improve ash dispersion forecasts. The results of this new four-channel algorithm for several scenes were compared to a threshold-based reverse absorption algorithm, where the reverse absorption algorithm is used to identify measurements with a negative 11–12-μm brightness temperature difference. The results indicate that the new four-channel algorithm is not only more sensitive to the presence of volcanic clouds but also generally less prone to false alarms than the standard reverse absorption algorithm. The greatest impact on detection sensitivity is seen in the Tropics, where water vapor can often mask the reverse absorption signal. The four-channel algorithm was able to detect volcanic clouds even when the 11–12-μm brightness temperature difference was greater than +2 K. In the higher latitudes, the greatest impact seen was the significant reduction in false alarms compared to the reverse absorption algorithm and the improved ability to detect optically thick volcanic clouds. Cloud water can also mask the reverse absorption signal. The four-channel algorithm was shown to be more sensitive to volcanic clouds that have a water (ice or liquid water) component than the reverse absorption algorithm.