bluuebunny/crossref_metadata_2025_split huggingface dataset:
Post Porosity Plasma Protection: Scaling of Efficiency with Porosity
Authors: Frot Theo , Volksen Willi , Purushothaman Sampath , Bruce Robert L. , Magbitang Teddie , Miller Dolores C. , Deline Vaughn R. , Dubois Geraud 
Published: April 2012

AbstractIncreasing the porosity of oxycarbosilane dielectrics is a key approach to lower the interconnect signal delay and thus enable manufacturing of lower power consumption and higher performance microprocessors. However, this path leads to excessive dielectric process damage as the industry adapts procedures developed for dense and microporous insulators to mesoporous materials. Currently ultralow dielectric constant (k) materials cannot be integrated at the most aggressive pitch. Here, it is reported that the post porosity plasma protection enables the mitigation of process damage across a wide range of porosity regimes. The exponential increase in plasma damage with porosity when going from microporous k = 2.4 to mesoporous k = 1.8 is shown. Using the same range of materials, the strategy allows a reduction in process damage to a constant minimal level on both blanket wafers and patterned structures. The results demonstrate how the strategy can enable the extendibility of current materials and processes to future technology nodes.
Thermoacoustic Emission from Carbon Nanotubes Imaged by Atomic Force Microscopy
Authors: Passeri Daniele , Sassi Ugo , Bettucci Andrea , Tamburri Emanuela , Toschi Francesco , Orlanducci Silvia , Terranova Maria Letizia , Rossi Marco 
Published: April 2012

AbstractThe thermoacoustic effect of isolated single‐wall carbon nanotubes aligned between electrodes is experimentally observed for the first time by imaging the emitted acoustic wave using an atomic force microscopy‐based technique specifically developed for the task. The capability of such a technique for single‐point thermoacoustic measurements is first verified on carbon nanotubes layers with two electrodes for injecting alternate electric current. The technique is then demonstrated to allow the acquisition, simultaneously with the topography, of images reflecting the pressure of the acoustic wave at fixed distance from the sample. Such a capability is used to collect images reflecting the amplitude of acoustic waves generated by isolated nanotubes and nanotube bundles by the thermoacoustic effect.
Carbon Nanofibers Prepared via Electrospinning
Authors: Inagaki Michio , Yang Ying , Kang Feiyu 
Published: April 2012

AbstractCarbon nanofibers prepared via electrospinning and following carbonization are summarized by focusing on the structure and properties in relation to their applications, after a brief review of electrospinning of some polymers. Carbon precursors, pore structure control, improvement in electrical conductivity,and metal loading into carbon nanofibers via electrospinning are discussed from the viewpoint of structure and texture control of carbon.
Does celiac disease occur in Afro‐derived Brazilian populations?
Authors: Almeida Rodrigo C. , Gandolfi Lenora , De Nazaré Klautau‐Guimarães Maria , Ferrari Íris , Sousa Sandra M.B. , Abe‐Sandes Kiyoko , Barbosa Ana A.L. , Simões Aguinaldo L. , Pratesi Riccardo , Oliveira Silviene F. 
Published: April 2012

AbstractBackground:Celiac disease is an autoimmune disorder that occurs in genetically susceptible individuals in whom the ingestion of dietary gluten induces intestinal mucosa inflammation. Previous studies suggest that celiac disease may either be very rare or underdiagnosed in African and/or African‐derived population.Aim:Determine the prevalence of celiac disease in Sub‐Saharan African‐derived Brazilian communities using serological screening.Subjects and methods:Inhabitants from 10 African‐derived communities from Northeastern of Brazil were screened for celiac disease. All sera were tested for endomysial class IgA antibody using indirect immunofluorescence.Results:No positive test for IgA‐endomysial was observed in the 860 individuals tested.Conclusion:Our data suggests a low prevalence of celiac disease in African‐derived Brazilian populations. Am. J. Hum. Biol., 2012. © 2012 Wiley Periodicals, Inc.
Energetics of thermoregulation by an industrious endotherm
Authors: Meehan Timothy D. 
Published: April 2012

AbstractObjectives:Thermoregulation by modern industrial humans is unique among endothermic animals, in that it is largely accomplished by controlling the temperature of our external environment. The objective of this study was to view the relationship between thermoregulatory energy use and environmental temperature in modern humans from the perspective of comparative physiology.Methods:Monthly residential energy use estimates from the US Energy Information Administration were divided by the annual number of American households from the US Census Bureau, giving average monthly energy consumption per American household for the years 2006 through 2010. Monthly energy consumption was then plotted against average monthly temperature across the United States from the National Climatic Data Center.Results:The resulting graph bore a striking resemblance to a classic Scholander‐Irving curve, exhibiting clear upper (22°C) and lower (15°C) critical temperatures, and an increase in energy use as temperatures extend above (90 W °C−1 increase) or below (244 W °C−1 decrease) those critical temperatures. Allometric equations from comparative physiology indicate that the energetic costs of our current thermoregulatory habits are ∼30 to 50 times those predicted for an endotherm of our size.Conclusions:Modern humans have redefined what it means to be a homeothermic endotherm, using large quantities of extrametabolic energy to regulate the temperature of our surroundings. Despite this sophistication, the signal of our individual physiology is readily discernible in national data on energy consumption. Am. J. Hum. Biol., 2012. © 2012 Wiley Periodicals, Inc.
Dielectric properties of high coercivity barium ferrite–natural rubber composites
Authors: Makled Mamoud H. 
Published: April 2012

AbstractThe effect of frequency, temperature, and BaFe12O19 (BF) content on the dielectric constant
$ \acute\varepsilon $, dielectric loss ε″, and tan δ were studied for barium ferrite—natural rubber composites (RFC). The dielectric constant for barium ferrite was related to the preparation method, meanwhile the dielectric constant of natural rubber (NR) is relatively large compared to the theoretical value. The results showed that
$ \acute\varepsilon $, ε″, and tan δ for RFC decrease as the frequency increases, however, at higher frequencies, the effect significantly weakens. At low ferrite loading, the dielectric properties are strongly influenced by BF content. Strong correlation between magnetic initial permeability and dielectric constant for hard magnetic material polymer composites was also observed. Increasing the content of barium ferrite in NR matrix enhances both ε″ and tan δ. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Comparative study of the rheological behavior of multiwalled carbon nanotubes and nanofiber composites prepared by the dilution of a masterbatch of polypropylene
Authors: Boronat T. , Garcia‐Sanoguera D. , Pascual J. , Peris F. , Sanchez‐Nacher L. 
Published: April 2012

AbstractIn this investigation, the characteristics and the rheological properties of two different nanocomposite systems were investigated. These systems consisted of a dispersion of carbon nanotubes (CNTs) and carbon nanofibers (CNFs) in a polypropylene (PP) matrix. The mixing process was carried out by melt compounding with a twin‐screw corotating extruder with different reinforcement amounts (0.2–20 wt %) from concentrated masterbatches (20 wt %) of PP/CNT and PP/CNF. The results show a remarkable increase in the viscosity for both blends as the reinforcement amount was increased. It was important to evaluate the rheological behavior to understand the effect of the nanocarbon particles on the internal structures and their processing properties of the obtained composites. CNFs were a more viable reinforcement from a processability point of view because the obtained viscosities of the PP/CNF blends were more manageable. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Preparation of a bagasse‐based anion exchange fiber for sugar decolorization
Authors: Liu Xilian , Lin Rijia , Chen Shuixia , Ma Nianfang , Huang Yunan 
Published: April 2012

AbstractSugar bagasse was converted into an anion‐exchanger through grafting acrylamide using (NH4)2Fe(SO4)2/H2O2 as initiator in an aqueous system, followed by reacting with ethylenediamine and hydrochloric acid. The effects of the grafting conditions such as monomer concentration, temperature, reaction time on the degree of grafting were investigated. The ion exchange capacity of the sugar bagasse base anion‐exchange fiber (SB‐IEF) was up to 3.70 mmol/g. Application of the SB‐IEF in sugar decolorization was evaluated. Compared with commercial strong basic anion exchange resin (AIER) and strong basic anion exchange fiber (AIEF), SB‐IEF showed the highest static decolorization capacity for sugar colorants (decolorization degree 71.40%), followed by AIEF (decolorization degree 68.74%) and AIER (decolorization degree 31.40%) at the same operating conditions. The dynamic decolorization results indicated that SB‐IEF showed larger processing volume than AIER and AIEF. SB‐IEF with higher grafting degree would have a higher decolorization degree. When 200 mL 2% brown granulated sugar solution was treated with 1 g SB‐IEF (grafting degree 82%), 80% decolorization degree could be achieved. The research results may provide a recyclable route for the comprehensive utilization of by‐products of sucrose industry. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Development of a new synthetic method based on in situ strategies for polyethylene/clay composites
Authors: Carrero Alicia , van Grieken Rafael , Suarez Inmaculada , Paredes Beatriz 
Published: April 2012

AbstractMethods to make polymer composites comprise melt and solution blending, but in the particular case of polyolefins they are not appropriate due to the weak interfacial adhesion. In the present work, in situ blended (ISB) together with in situ polymerization (ISP) processes have been employed and compared using MAO/(nBuCp)2ZrCl2 as catalytic system and sepiolite clay as additive in ethylene polymerization. A new method as a combination of the previous ones (ISB + ISP) has been developed and applied to the synthesis of linear low‐density polyethylene (LLDPE). When ISB + ISP method is employed high catalytic activities are observed and this combination allows to increase the storage modulus at 25°C up to 26% with 2.8 wt % of clay in LLDPE when silica is employed as catalyst carrier; in that way, copolymer particles with good morphology with higher storage modulus are obtained, useful properties for their use in specific applications. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
The effect of crosslinking on the adsorption behavior of copper (II) onto poly(2‐hydroxy‐4‐acryloyloxybenzophenone)
Authors: Zalloum Hiba M. , El‐Eswed Bassam , Zalloum Ruba M. , Mubarak Mohammad S. 
Published: April 2012

AbstractThe adsorption behavior of Cu(II) ions onto poly(2‐hydroxy‐4‐acryloyloxybenzophenone), polymer I, and onto poly(2‐hydroxy‐4‐acryloyloxybenzophenone) crosslinked with different amounts of divinylbenzene (DVB), polymers II, III, and IV, in aqueous solutions was investigated using batch adsorption experiments as a function of contact time, pH, and temperature. The amount of metal ion uptake of the polymers was determined by using atomic absorption spectrometry (AAS) and the highest uptake was achieved at pH 7.0 and by using perchlorate as an ionic strength adjuster for polymers I, II, III, and IV. Results revealed that the adsorption capacity (qe and Qm) of Cu(II) ions decreases with increasing crosslinking due to the decrease of chelation sites. In addition, the rate of adsorption (k2) of Cu(II) ions decreases with the increase of crosslinking because it becomes more difficult for Cu(II) ions to diffuse into the chelation sites. The isothermal behavior and the kinetics of adsorption of Cu(II) ions on these polymers with respect to the initial mass of the polymer and temperature were also investigated. The experimental data of the adsorption process was found to correlate well with the Langmuir isotherm model. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Spectroscopic evidence of charge exchange X‐ray emission from galaxies
Authors: Wang Q.D. , Liu J. 
Published: April 2012

AbstractWhat are the origins of the soft X‐ray line emission from non‐AGN galaxies? XMM‐Newton RGS spectra of nearby non‐AGN galaxies (including starforming ones: M82, NGC 253, M51, M83, M61, NGC 4631, M94, NGC 2903, and the Antennae galaxies, as well as the inner bulge of M31) have been analyzed. In particular, the Kα triplet of O VII shows that the resonance line is typically weaker than the forbidden and/or inter‐combination lines. This suggests that a substantial fraction of the emission may not arise directly from optically thin thermal plasma, as commonly assumed, and may instead originate at its interface with neutral gas via charge exchange. This latter origin naturally explains the observed spatial correlation of the emission with various tracers of cool gas in some of the galaxies. However, alternative scenarios, such as the resonance scattering by the plasma and the relic photo‐ionization by AGNs in the recent past, cannot be ruled out, at least in some cases, and are being examined. Such X‐ray spectroscopic studies are important to the understanding of the relationship of the emission to various high‐energy feedback processes in galaxies (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cometary charge exchange diagnostics in UV and X‐ray
Authors: Bodewits D. , Christian D.J. , Carter J.A. , Dennerl K. , Ewing I. , Hoekstra R. , Lepri S.T. , Lisse C.M. , Wolk S.J. 
Published: April 2012

AbstractSince the initial discovery of cometary charge exchange emission, more than 20 comets have been observed with a variety of X‐ray and UV observatories. This observational sample offers a broad variety of comets, solar wind environments and observational conditions. It clearly demonstrates that solar wind charge exchange emission provides a wealth of diagnostics, which are visible as spatial, temporal, and spectral emission features. We review the possibilities and limitations of each of those in this contribution (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Charge transfer processes from low to intermediate energies
Authors: Bacchus‐Montabonel M.C. 
Published: April 2012

AbstractThe theoretical treatment of charge transfer processes is developed using ab‐initio molecular calculations. Semi‐classical and quantal dynamical approaches are presented for the determination of cross sections and rate constants which are important data for space chemistry models. Accurate cross section values may be determined, taking account of rotational couplings with regard to the collision energy. Such theoretical approaches provide besides an insight into the mechanism of these processes with consideration of anisotropic and vibrational effects for collisions with diatomic molecular targets (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Suzaku observations of charge exchange emission from solar system objects
Authors: Ezoe Y. , Fujimoto R. , Yamasaki N.Y. , Mitsuda K. , Ohashi T. , Ishikawa K. , Oishi S. , Miyoshi Y. , Terada N. , Futaana Y. , Porter F.S. , Brown G.V. 
Published: April 2012

AbstractRecent results of charge exchange emission from solar system objects observed with the Japanese Suzaku satellite are reviewed. Suzaku is of great importance to investigate diffuse X‐ray emission like the charge exchange from planetary exospheres and comets. The Suzaku studies of Earth's exosphere, Martian exosphere, Jupiter's aurorae, and comets are overviewed (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Update on modeling and data analysis of heliospheric solar wind charge exchange X‐ray emission
Authors: Koutroumpa D. 
Published: April 2012

AbstractAbout 15 years ago, charge exchange (CX) X‐ray emission was discovered in comet observations, and was identified as the radiative decay of excited states of highly‐charge solar wind ions populated in collisions with neutral cometary material. This non‐thermal X‐ray emission mechanism is now generally acknowledged in planetary environments (e.g. Mars, Earth), as well as interstellar atoms sweeping through the heliosphere. In this paper I present the most recent improvements made in simulations of the heliospheric CX X‐ray emission. The model results are compared to X‐ray data from Suzaku, XMM‐Newton and Chandra spanning over a 10‐year period, and some conclusions are drawn on the heliospheric contribution to the diffuse soft X‐ray background. The solar system CX X‐ray sources can serve as prototypes in terms of modeling and diagnostics to more distant astrophysical objects where CX emission signatures are being discovered (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the soft X‐ray emission of M82
Authors: Liu J. , Wang Q.D. , Mao S. 
Published: April 2012

AbstractWe present a spatial analysis of the soft X‐ray and Hα emissions from the outflow of the starburst galaxy M82. We find that the two emissions are tightly correlated on various scales. The O VII triplet of M82, as resolved by X‐ray grating observations of XMM‐Newton, is dominated by the forbidden line, inconsistent with the thermal prediction. The O VII triplet also shows some spatial variations. We discuss three possible explanations for the observed O VII triplet, including the charge exchange at interfaces between the hot outflow and neutral cool gas, a collisional non‐equilibrium‐ionization recombining plasma, and resonance scattering (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ion‐ion charge exchange and X‐rays from the winds of hot stars
Authors: Pollock A.M.T. 
Published: April 2012

AbstractCharge exchange occurs between charged ions with enough energy to overcome Coulomb repulsion, a condition satisfied for collisions at velocities like those of the winds driven from hot stars by radiation pressure. X‐ray line ratios in some hot stars are inconsistent with those expected from thermal plasmas excited by electron impact. Ion‐ion interactions including charge exchange might be responsible instead if high‐velocity collisions between ions are enabled by the presence of a magnetic field in the wind, suggesting a possible alternative mechanism to the widely accepted instability‐driven shock model. The nature of a plasma in charge‐exchange equilibrium is yet to be determined (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Charge‐exchange emission in the starburst galaxies M82 and NGC3256
Authors: Ranalli P. 
Published: April 2012

AbstractCharge‐exchange (CE) emission produces features which are detectable with the current X‐ray instrumentation in the brightest near galaxies. We describe these aspects in the observed X‐ray spectra of the star forming galaxies M82 and NGC 3256, from the Suzaku and XMM‐Newton telescopes. Emission from both ions (O, C) and neutrals (Mg, Si) is recognised. We also describe how microcalorimeter instrumentation on future missions will improve CE observations (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Charge transfer X‐rays in solar and stellar flares
Authors: Raymond J.C. 
Published: April 2012

AbstractMost of the energy in a solar flare, and presumably a stellar flare as well, takes the form of a power law of energetic particles. The energetic electrons produce a bremsstrahlung continuum, while the most energetic nuclei produce gamma‐rays. Nuclei around 1 MeV/AMU can produce X‐rays during and after charge transfer with neutrals. This paper predicts the fluxes for some prominent X‐ray lines and compares them to existing spectra (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Solar wind charge exchange during geomagnetic storms
Authors: Robertson I.P. , Cravens T.E. , Sibeck D.G. , Collier M.R. , Kuntz K.D. 
Published: April 2012

AbstractOn 2001 March 31 a coronal mass ejection pushed the subsolar magnetopause to the vicinity of geosynchronous orbit at 6.6 RE. The NASA/GSFC Community Coordinated Modeling Center (CCMC) employed a global magnetohydrodynamic (MHD) model to simulate the solar wind‐magnetosphere interaction during the peak of this geomagnetic storm. Robertson et al. then modeled the expected soft X‐ray emission due to solar wind charge exchange with geocoronal neutrals in the dayside cusp and magnetosheath. The locations of the bow shock, magnetopause and cusps were clearly evident in their simulations. Another geomagnetic storm took place on 2000 July 14 (Bastille Day). We again modeled X‐ray emission due to solar wind charge exchange, but this time as observed from a moving spacecraft. This paper discusses the impact of spacecraft location on observed X‐ray emission and the degree to which the locations of the bow shock and magnetopause can be detected in images (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
AXIOM: Advanced X‐ray imaging of the magnetosheath
Authors: Sembay S. , Branduardi‐Raymont G. , Eastwood J.P. , Sibeck D.G. , Abbey A. , Brown P. , Carter J.A. , Carr C.M. , Forsyth C. , Kataria D. , Kemble S. , Milan S. , Owen C.J. , Read A.M. , Peacocke L. , Arridge C.S. , Coates A.J. , Collier M.R. , Cowley S.W.H. , Fazakerley A.N. , Fraser G. , Jones G.H. , Lallement R. , Lester M. , Porter F.S. , Yeoman T. 
Published: April 2012

AbstractAXIOM (Advanced X‐ray Imaging Of the Magnetosphere) is a concept mission which aims to explain how the Earth's magnetosphere responds to the changing impact of the solar wind using a unique method never attempted before; performing wide‐field soft X‐ray imaging and spectroscopy of the magnetosheath, magnetopause and bow shock at high spatial and temporal resolution. Global imaging of these regions is possible because of the solar wind charge exchange (SWCX) process which produces elevated soft X‐ray emission from the interaction of high charge‐state solar wind ions with primarily neutral hydrogen in the Earth's exosphere and near‐interplanetary space (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tracing low‐energy cosmic‐rays by charge exchange X‐ray emission
Authors: Tatischeff V. 
Published: April 2012

AbstractHadronic cosmic rays of energies below about 100 MeV nucleon–1 are thought to be an important component of the Galactic ecosystem. However, since these particles cannot be detected near Earth due to the solar modulation effect, their composition and flux in the interstellar medium are very uncertain. Atomic interactions of low‐energy cosmic rays with interstellar gas can produce a characteristic nonthermal X‐ray emission comprising very broad lines from de‐excitations in fast ions following charge exchange. We suggest that broad lines at ∼0.57 and ∼0.65 keV could be detected from a dark molecular cloud in the local interstellar medium. These lines would be produced by fast oxygen ions of kinetic energies around 1 MeV nucleon–1 (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
X‐rays from charge transfer in astrophysics: Overview
Authors: Raymond J.C. 
Published: April 2012

AbstractX‐rays produced by charge transfer provide a major fraction of the soft X‐ray background. If they contribute significantly to emission from other astrophysical sources, then model fits that ignore them will yield wrong answers, and an important diagnostic opportunity will be missed. Several recent papers suggest charge transfer contributions to observed X‐ray spectra. This informal overview discusses analysis that might confirm the charge transfer interpretation and carry it toward the status of a useful diagnostic (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)