bluuebunny/crossref_metadata_2025 huggingface dataset:
Equal Opportunities and Diversity: Exploring the Relevance of Le Grand's Models of Service Provision
Authors: Powell Martin , Johns Nick , Green Alison
Published: November 2012

The purpose of this article is to draw on Le Grand's (2007) model of service provision of ends and means (trust, targets, voice and choice) to critique the accepted frameworks for conceptualising the chronology of equal opportunities and diversity (EO&D) in the UK. We do this by reviewing the attempts to provide a chronological analysis before outlining and applying Le Grand's (2007) model. We find that the ‘eras’ of the chronologies give way to a much more complex and fluid picture. Moreover, focusing on ends and means highlights some major issues in the development of EO&D policy that needs to be addressed.
The impact of patient quality of life and spirituality upon caregiver depression for those with advanced cancer
Authors: Douglas Sara L. , Daly Barbara J.
Published: November 2012

Objective:

Little is known about relationships between patient spiritual well-being and caregiver outcomes for those with advanced cancer. We were interested in examining the relationship between patient physical quality of life (QOL) and caregiver depression and to also evaluate whether patient spiritual well-being (SWB) played a mediating role in this relationship.

Method:

This is a prospective longitudinal study that was conducted in the outpatient clinics at a university-affiliated comprehensive cancer center. 226 patients with Stage III or IV cancer (lung, GI, GYN) and their primary caregivers were interviewed upon enrollment into the study and three months later. Measures of spirituality, health-related quality of life, and physical functioning were included in the interviews.

Results:

Key findings were that the relationship between patient physical QOL and caregiver depression was inverse and moderate (β = −0.24, p = 0.004) and that patient SWB (meaning/peace) played a significant (p = 0.02) and medium-size role (β = −0.31) in mediating the relationship between patient physical QOL and caregiver depression. The nature of these relationships was stable over time.

Significance of results:

Patients' spirituality is central to their coping and adjusting to cancer. It is this aspect of patient overall quality of life that mediates the relationship to caregiver well-being. The most potent intervention for caregiver depression may be attending to patient spiritual distress.
National Human Rights Commissions and Asian Human Rights Norms
Authors: WOLMAN Andrew
Published: November 2012

Ever since the beginning of the “Asian Values” debate in the early 1990s, there have been efforts on the part of many societal actors to establish distinctively Asian human rights norms that integrate local customary values and international human rights norms. This article presents the claim that National Human Rights Commissions in Asia are well placed to play an important role in this effort to develop localized human rights norms because of their close links with local civil actors, along with their independence from government control, pluralistic make-up, and ability to address complex rights issues in detail. The article also presents a study of how the National Human Rights Commission of Korea has used its powers to prioritize and promote a particularly Korean version of the human rights of the elderly.
Wisconsin Twin Research: Early Development, Childhood Psychopathology, Autism, and Sensory Over-responsivity
Authors: Schmidt Nicole L. , Van Hulle Carol A. , Brooker Rebecca J. , Meyer Lauren R. , Lemery-Chalfant Kathryn , Goldsmith H. Hill
Published: November 2012

The Wisconsin Twin Research Program comprises multiple longitudinal studies that utilize a panel recruited from statewide birth records for the years 1989 through 2004. Our research foci are the etiology and developmental course of early emotions, temperament, childhood anxiety and impulsivity, autism, sensory over-responsivity, and related topics. A signature feature of this research program is the breadth and depth of assessment during key periods of development. The assessments include extensive home- and laboratory-based behavioral batteries, recorded sibling and caregiver interactions, structured psychiatric interviews with caregivers and adolescents, observer ratings of child behavior, child self-report, cognitive testing, neuroendocrine measures, medical records, dermatoglyphics, genotyping, and neuroimaging. Across the various studies, testing occasions occurred between 3 months and 18 years of age. Data collection for some aspects of the research program has concluded and, for other aspects, longitudinal follow-ups are in progress.
Functional Approaches to Lifespan Development
Authors: Martin Mike , Jäncke Lutz , Röcke Christina
Published: November 2012

Most of lifespan research focuses on age-related changes and plasticity as early markers of decline or performance improvements achieved through training interventions. This special issue on functional approaches to lifespan development focuses on age-related stabilization in complex functions such as cognitive and motor performance and well-being on the levels of brain and behavior. One central question focuses on what elements have to change for individually important outcomes to remain stable in old age, putting the many experimental studies on the plasticity of elementary processes in the context of the recognition that aging individuals most often successfully manage their development and maintain high levels of functioning. Aging research will profit from understanding the processes and potentials of lifespan developmental stabilization.
The 1707 Mw8.7 Hoei earthquake triggered the largest historical eruption of Mt. Fuji
Authors: Chesley Christine , LaFemina Peter C. , Puskas Christine , Kobayashi Daisuke
Published: November 2012

Studies in magma‐tectonics point to a spatiotemporal correlation between earthquakes and volcanic eruptions. Here, we examine the correlation between two great Japanese earthquakes, the 1703 Mw 8.2 Genroku and 1707 Mw 8.7 Hoei, and Mt. Fuji's explosive (VEI 5) Hoei eruption, 49 days after the 1707 earthquake. We model the static stress changes and dilatational strain imparted on the Mt. Fuji magmatic system due to each earthquake to determine if these mechanisms enhanced the potential for eruption. Our results show that both earthquakes clamped the dike from 8 km to the surface and compressed magma chambers at 8 km and 20 km depths. The 1707 earthquake decreased the normal stress on the dike at 20 km, the proposed depth of a basaltic magma chamber, by 1.06 bars (0.106 MPa). We hypothesize that the stress change and strain generated by the 1707 earthquake triggered the eruption of Mt. Fuji by permitting opening of the dike and ascent of basaltic magma from 20 km into andesitic and dacitic magma chambers located at 8 km depth. The injection of basaltic magma into the more evolved magmatic system induced magma mixing and a Plinian eruption ensued.
Surface waves of the 2011 Tohoku earthquake: Observations of Taiwan's dense high‐rate GPS network
Authors: Hung Huang‐Kai , Rau Ruey‐Juin
Published: November 2012

Surface waves generated by the 2011 Mw 9.0 Tohoku, Japan earthquake were recorded by both the high‐rate GPS and broadband seismic stations in Taiwan. In this study, we investigate the precision of high‐rate GPS displacements and estimate the feasibility of using GPS for seismology study in Taiwan. One hertz observations of 210 continuous GPS stations in Taiwan and neighboring islands were processed using a precise point positioning technique to estimate the absolute epoch‐by‐epoch positions generated by the Tohoku earthquake. Modified sidereal filtering was used to correct for near‐daily periodical variations of high‐rate position time series that may be influenced by multipath effects, and a band‐pass filter was used to remove noises from marginal frequencies. For all the 210 stations, the GPS precision after modified sidereal filtering improved from 8.2 to 7.4 mm in the horizontal and from 19.5 to 12.7 mm in the vertical components except for about 20% of the data with large position errors. After applying the band‐pass filter in the teleseismic frequency band (0.008–0.08 Hz), excluding 54 stations with noisy data, 156 continuous GPS stations were selected. Surface wave displacements derived from both high‐rate GPS and broadband seismometers are highly consistent, and the correlation coefficients are enhanced by a band‐pass filter (0.008–0.08 Hz) from 0.85 to 0.95 in the horizontal and from 0.58 to 0.85 in the vertical components. We consider continuous GPS can be used as an alternative approach to study characteristics of surface wave propagation in Taiwan.
Detection of radioactive 35S at Fukushima and other Japanese sites
Authors: Priyadarshi Antra , Hill‐Falkenthal Jason , Thiemens Mark H. , Yoshida Naohiro , Toyoda Sakae , Yamada Keita , Mukotaka Arata , Fujii Ayako , Uematsu Mitsuo , Hatakeyama Shiro , Noguchi Izumi , Nojiri Yukihiro , Tanimoto Hiroshi
Published: November 2012

The Fukushima nuclear power plant was severely damaged by an earthquake and concomitant tsunami during March 2011. An effect of this disaster was secondary formation of radioactive 35S via the 35Cl(n,p)35S reaction, when neutrons from the partially melted reactor cores activated the coolant sea water. Here we report the first measurements of 35S in sulfate aerosols and rain water collected at six Japanese sampling sites, Hokkaido, Tsukuba, Kashiwa, Fuchu, Yokohama, and Fukushima, during March‐September 2011. The measured 35SO42‐ concentrations in aerosols vary significantly. The Kashiwa (AORI) site shows the highest 35SO42‐ concentration (6.1 × 104 ± 200 atoms/m3) on 1 April 2011, which is nearly 100 times higher than the natural background activity. Considering the percentage loss of 35SO42‐ resulting from dry and wet deposition and dilution of the radiation plume in the boundary layer during transport, it was determined that the surface air concentration of 35SO42‐ at the Fukushima would have been 2.8 × 105 atoms/m3 during the week after the earthquake, which is in agreement with the model prediction [Priyadarshi et al., ]. 35SO42‐ activity in rain water collected during March‐May 2011 at Tokyo Tech Yokohama varies from 1.1 × 105 to 9.8 × 105 atoms/liter, whereas stream water collected near Fukushima was found to have 1.2 × 105 atoms/liter during April. Even after 6 months, 35SO42‐ activity remains very high (9.9 × 104 ± 770 atoms/m3) in the marine boundary layer in the Fukushima region, which implies that the reactor core was producing radioactive sulfur.
Soluble salt accumulations in Taylor Valley, Antarctica: Implications for paleolakes and Ross Sea Ice Sheet dynamics
Authors: Toner Jonathan D. , Sletten Ronald S. , Prentice Michael L.
Published: November 2012

Soluble salt accumulations in soils of Taylor Valley, Antarctica, provide a history of paleolakes and the advance of the Ross Sea Ice Sheet (RSIS). In western Taylor Valley, soluble salt accumulations are relatively high and are composed primarily of Na+, Ca2+, Cl–, and SO42–. In eastern Taylor Valley, soluble salt accumulations are much lower and are composed primarily of Na+ and HCO3–. Na‐HCO3‐rich compositions in eastern Taylor Valley are formed through leaching, calcite dissolution, and cation exchange reactions and appear to influence the chemistry of nearby streams and lakes. The data presented here support hypotheses that a lobe of the RSIS expanded into eastern Taylor Valley and dammed proglacial paleolakes. However, in contrast to previous studies, our findings indicate that the RSIS advanced deeper into Taylor Valley and that paleolakes were less extensive. By comparing soluble salt distributions across Taylor Valley, we conclude that a lobe of the RSIS filled all of eastern Taylor Valley and dammed paleolakes in western Taylor Valley up to approximately 300 m elevation. Following ice retreat, smaller paleolakes formed in both western and eastern Taylor Valley up to about 120 m elevation, with prominent still‐stands controlled by the elevation of major valley thresholds. At higher elevations, soluble salt accumulations are consistent with older soils that have not been affected by the most recent RSIS advance.
Formation of metallic magnetic clusters in a Kondo-lattice metal: Evidence from an optical study
Authors: Kovaleva N. N. , Kugel K. I. , Bazhenov A. V. , Fursova T. N. , Löser W. , Xu Y. , Behr G. , Kusmartsev F. V.
Published: November 2012

Magnetic materials are usually divided into two classes: those with localised magnetic moments and those with itinerant charge carriers. We present a comprehensive experimental (spectroscopic ellipsomerty) and theoretical study to demonstrate that these two types of magnetism do not only coexist but complement each other in the Kondo-lattice metal, Tb2PdSi3. In this material the itinerant charge carriers interact with large localised magnetic moments of Tb(4f) states, forming complex magnetic lattices at low temperatures, which we associate with self-organisation of magnetic clusters. The formation of magnetic clusters results in low-energy optical spectral weight shifts, which correspond to opening of the pseudogap in the conduction band of the itinerant charge carriers and development of the low- and high-spin intersite electronic transitions. This phenomenon, driven by self-trapping of electrons by magnetic fluctuations, could be common in correlated metals, including besides Kondo-lattice metals, Fe-based and cuprate superconductors.
Integrated Forest Biorefineries: Sustainability Considerations for Forest Biomass Feedstocks
Authors: Patton-Mallory Marcia , Skog Kenneth E. , Dale Virginia H.
Published: November 2012

Forest biomass feedstocks have the potential to contribute significantly to bioenergy production in the United States. The forestry sector has adopted guidelines and certification systems for forest products such as lumber and paper produced from sustainable forestry. This chapter discusses the extension of these concepts to bioenergy from forests along with proposed sustainability measures, renewable biomass definitions, and how these may influence woody biomass supplied to integrated biorefineries.
Prehydrolysis Pulping with Fermentation Coproducts
Authors: Wegner T. H. , Houtman C. J. , Rudie A. W. , Illman B. L. , Ince P. J. , Bilek E. M. , Jeffries T. W.
Published: November 2012

Prehydrolysis coupled with traditional pulping methods is a forest biorefinery approach to add valuable fermentation-based coproducts to existing pulp and paper production. This chapter will review research on pulping procedures to release the hemicellulose extract from commercially important wood species; extract hydrolysis, inhibitor removal, concentration; ethanol fermentation of the resulting hydrolysate sugars; engineering process modeling and economic modeling.
An investigation of the Young's modulus of single-crystalline wurtzite indium nitride using an atomic force microscopy based micromechanical bending test
Authors: Lu Yen-Sheng , Hsieh Chih-Hung , Gwo Shangjr , Hou Max T. , Yao Jung-Sheng , Yeh J. Andrew
Published: November 2012

High quality single-crystalline wurtzite indium nitride (InN) thin film was first demonstrated to have a Young's modulus of 149 ± 5 GPa along a-axis using atomic force microscopy microbending test since the revision of InN energy gap. These released InN cantilever beams were examined to have ignorable in-plane residual stress using micro-Raman spectroscopy, where the E2 (high) mode at 490 cm−1 exists zero shift because of the perfect lattice match (8:9 commensurate) between InN and underneath aluminum nitride buffer. The experimental value of Young's modulus agrees well with a number of theoretical estimations ranging from 146 to 159 GPa.
The effect of rotation on the Rayleigh-Bénard stability threshold
Authors: Prosperetti Andrea
Published: November 2012

The standard method used to solve the Rayleigh-Bénard linear stability problem for a rotating fluid leads to a complex expression which can only be evaluated numerically. Here the problem is solved by a different method similar to that used in a recent paper on the non-rotating case [A. Prosperetti, “A simple analytic approximation to the Rayleigh-Bénard stability threshold,” Phys. Fluids 23, 124101 (2011)10.1063/1.3662466]. In principle the method leads to an exact result which is not simpler than the standard one. Its value lies in the fact that it is possible to obtain from it an approximate explicit analytic expression for the dependence of the Rayleigh number on the wave number of the perturbation and the rate of rotation at marginal stability conditions. Where the error can be compared with exact results in the literature, it is found not to exceed a few percent over a very broad Taylor number range. The relative simplicity of the approach permits us, among others, to account for the effects of a finite thermal conductivity of the plates, which have not been studied before.
Accounting for intra-molecular vibrational modes in open quantum system description of molecular systems
Authors: Roden Jan , Strunz Walter T. , Whaley K. Birgitta , Eisfeld Alexander
Published: November 2012

Electronic-vibrational dynamics in molecular systems that interact with an environment involve a large number of degrees of freedom and are therefore often described by means of open quantum system approaches. A popular approach is to include only the electronic degrees of freedom into the system part and to couple these to a non-Markovian bath of harmonic vibrational modes that is characterized by a spectral density. Since this bath represents both intra-molecular and external vibrations, it is important to understand how to construct a spectral density that accounts for intra-molecular vibrational modes that couple further to other modes. Here, we address this problem by explicitly incorporating an intra-molecular vibrational mode together with the electronic degrees of freedom into the system part and using the Fano theory for a resonance coupled to a continuum to derive an “effective” bath spectral density, which describes the contribution of intra-molecular modes. We compare this effective model for the intra-molecular mode with the method of pseudomodes, a widely used approach in simulation of non-Markovian dynamics. We clarify the difference between these two approaches and demonstrate that the respective resulting dynamics and optical spectra can be very different.
Finite time singularities for water waves with surface tension
Authors: Castro Angel , Córdoba Diego , Fefferman Charles , Gancedo Francisco , Gómez-Serrano Javier
Published: November 2012

Here we consider the 2D free boundary incompressible Euler equation with surface tension. We prove that the surface tension does not prevent a finite time splash or splat singularity, i.e., the curve touches itself either in a point or along an arc. To do so, the main ingredients of the proof are a transformation to desingularize the curve and a priori energy estimates.
Carbon nanotube film interlayer for strain and damage sensing in composites during dynamic compressive loading
Authors: Wu A. S. , Na W.-J. , Yu W.-R. , Byun J.-H. , Chou T.-W.
Published: November 2012

A major challenge in the damage assessment of materials under dynamic, high strain rate loading lies in the inability to apply most health monitoring methodologies to the analysis and evaluation of damage incurred on short timescales. Here, we present a resistance-based sensing method utilizing an electrically conductive carbon nanotube film in a fiberglass/vinyl ester composite. This method reveals that applied strain and damage in the form of matrix cracking and delamination give rise to electrical resistance increases across the composite specimen; these can be measured in real-time during high strain rate loading. Damage within the composite specimens is confirmed through pre- and post-mortem x-ray micro computed tomography imaging.
Computation of multi-region relaxed magnetohydrodynamic equilibria
Authors: Hudson S. R. , Dewar R. L. , Dennis G. , Hole M. J. , McGann M. , von Nessi G. , Lazerson S.
Published: November 2012

We describe the construction of stepped-pressure equilibria as extrema of a multi-region, relaxed magnetohydrodynamic (MHD) energy functional that combines elements of ideal MHD and Taylor relaxation, and which we call MRXMHD. The model is compatible with Hamiltonian chaos theory and allows the three-dimensional MHD equilibrium problem to be formulated in a well-posed manner suitable for computation. The energy-functional is discretized using a mixed finite-element, Fourier representation for the magnetic vector potential and the equilibrium geometry; and numerical solutions are constructed using the stepped-pressure equilibrium code, SPEC. Convergence studies with respect to radial and Fourier resolution are presented.
Assessment of a high-resolution candidate detector for prostate time-of-flight positron emission tomography
Authors: Cosentino Luigi , Finocchiaro Paolo , Pappalardo Alfio , Garibaldi Franco
Published: November 2012

We report on the measurements performed using a 22Na source on a detector element for a magnetic resonance imaging-compatible time-of-flight-positron emission tomography endorectal prostate probe, with depth-of-interaction sensitivity. It is made from a LYSO scintillator crystal, wrapped with Lumirror, readout at both ends by means of silicon photomultipliers. With a detailed description of the data analysis procedure, we show that our results point to a 400 ps coincidence resolving time and, at the same time, to a depth-of-interaction resolution of 1 mm. These appealing features, along with the tiny 1.5 mm × 1.5 mm × 10 mm crystal size, are quite promising in view of the realization of a prototype probe.
Coupling between interface and velocity perturbations in the weakly nonlinear Rayleigh-Taylor instability
Authors: Wang L. F. , Wu J. F. , Fan Z. F. , Ye W. H. , He X. T. , Zhang W. Y. , Dai Z. S. , Gu J. F. , Xue C.
Published: November 2012

Weakly nonlinear (WN) Rayleigh-Taylor instability (RTI) initiated by single-mode cosinusoidal interface and velocity perturbations is investigated analytically up to the third order. Expressions of the temporal evolutions of the amplitudes of the first three harmonics are derived. It is shown that there are coupling between interface and velocity perturbations, which plays a prominent role in the WN growth. When the “equivalent amplitude” of the initial velocity perturbation, which is normalized by its linear growth rate, is compared to the amplitude of the initial interface perturbation, the coupling between them dominates the WN growth of the RTI. Furthermore, the RTI would be mitigated by initiating a velocity perturbation with a relative phase shift against the interface perturbation. More specifically, when the phase shift between the interface perturbation and the velocity perturbation is π and their equivalent amplitudes are equal, the RTI could be completely quenched. If the equivalent amplitude of the initial velocity perturbation is equal to the initial interface perturbation, the difference between the WN growth of the RTI initiated by only an interface perturbation and by only a velocity perturbation is found to be asymptotically negligible. The dependence of the WN growth on the Atwood numbers and the initial perturbation amplitudes is discussed. In particular, we investigate the dependence of the saturation amplitude (time) of the fundamental mode on the Atwood numbers and the initial perturbation amplitudes. It is found that the Atwood numbers and the initial perturbation amplitudes play a crucial role in the WN growth of the RTI. Thus, it should be included in applications where the seeds of the RTI have velocity perturbations, such as inertial confinement fusion implosions and supernova explosions.
Detailed study of the direct numerical observation of the Kramers turnover in the LiNC⇌LiCN isomerization rate
Authors: Müller P. L. García , Hernandez Rigoberto , Benito R. M. , Borondo F.
Published: November 2012

According to Kramers, rates of molecular process are expected to follow a rise and fall from low friction (at little to no interaction with the environment) to high friction (at typical liquid densities and above). This so-called Kramers turnover was recently observed and delineated in the case of the LiNC⇌LiCN isomerization reaction in the presence of an argon bath [P. García-Müller, R. Hernandez, R. M. Benito, and F. Borondo, Phys. Rev. Lett. 101, 178302 (2008)]10.1103/PhysRevLett.101.178302. The rates were obtained using direct molecular dynamics of an all-atom representation and the Langevin dynamics of a projected representation. We now provide further evidence that the forward and backward rates are indeed exhibiting the turnover. The rates are also seen to agree remarkably well with the Pollak-Grabert-Hänggi rate formulas in regimes satisfying the theory underlying assumptions. At higher temperatures, when the theory is expected to fail, the solvated LiCN isomerization continues to exhibit activated dynamics following the turnover.
Third-order nonlinearity of metal nanoparticles: Isolation of instantaneous and delayed contributions
Authors: Jayabalan J. , Singh Asha , Khan Salahudin , Chari Rama
Published: November 2012

Measurement of transient absorption of a sample allows estimation of the evolution of the nonlinear response of materials after excitation by a short pump pulse. In this work, the time dependent nonlinear response of silver nanoplatelets in water was measured using transient absorption technique for various volume fractions of silver in water. These measurements were carried out in subpicosecond time scales and a suitable theoretical model was developed. It is been shown that the hot-electron contribution to the third-order nonlinearity of metal colloids is much higher than its instantaneous third-order nonlinearity. At low volume fractions, the delayed hot-electron contribution to third-order nonlinearity increases linearly with the volume fraction.
Ring polymer molecular dynamics with surface hopping
Authors: Shushkov Philip , Li Richard , Tully John C.
Published: November 2012

We propose a ring polymer molecular dynamics method for the calculation of chemical rate constants that incorporates nonadiabatic effects by the surface-hopping approach. Two approximate ring polymer electronic Hamiltonians are formulated and the time-dependent Schrodinger equation for the electronic amplitudes is solved self-consistently with the ring polymer equations of motion. The beads of the ring polymer move on a single adiabatic potential energy surface at all times except for instantaneous surface hops. The probability for a hop is determined by the fewest-switches surface-hopping criterion. During a surface hop all beads switch simultaneously to the new potential energy surface with positions kept unchanged and momenta adjusted properly to conserve total energy. The approach allows the evaluation of total rate coefficients as well as electronic state-selected contributions. The method is tested against exact quantum mechanical calculations for a one-dimensional, two-state model system that mimics a prototypical nonadiabatic bimolecular chemical reaction. For this model system, the method reproduces quite accurately the tunneling contribution to the rate and the distribution of reactants between the electronic states.
Chaotic saddles in nonlinear modulational interactions in a plasma
Authors: Miranda Rodrigo A. , Rempel Erico L. , Chian Abraham C.-L.
Published: November 2012

A nonlinear model of modulational processes in the subsonic regime involving a linearly unstable wave and two linearly damped waves with different damping rates in a plasma is studied numerically. We compute the maximum Lyapunov exponent as a function of the damping rates in a two-parameter space, and identify shrimp-shaped self-similar structures in the parameter space. By varying the damping rate of the low-frequency wave, we construct bifurcation diagrams and focus on a saddle-node bifurcation and an interior crisis associated with a periodic window. We detect chaotic saddles and their stable and unstable manifolds, and demonstrate how the connection between two chaotic saddles via coupling unstable periodic orbits can result in a crisis-induced intermittency. The relevance of this work for the understanding of modulational processes observed in plasmas and fluids is discussed.
Phase evolution of magnetite nanocrystals on oxide supports via template-free bismuth ferrite precursor approach
Authors: Cheung Jeffrey , Bogle Kashinath , Cheng Xuan , Sullaphen Jivika , Kuo Chang-Yang , Chen Ying-Jiun , Lin Hong-Ji , Chen Chien-Te , Yang Jan-Chi , Chu Ying-Hao , Valanoor Nagarajan
Published: November 2012

This report investigates the phase evolution pathway of magnetite nanocrystal synthesis on oxide-supported substrates. A template-free phase separation approach, which exploits the thermodynamic instability of ternary perovskite BiFeO3 and inherent volatility of bismuth oxide in low oxygen pressure and high temperature is presented. The formation of an intermediate hematite nanocrystal phase is found as a key step that controls the eventual size and morphology of the magnetite nanocrystals. X-ray absorption spectra measurements and X-ray magnetic circular dichroism confirm that the spectral fingerprints of the magnetite nanocrystals match with that of bulk crystals. Magnetic measurements show that magnetic anisotropy is directly attributed to the nanocrystal morphology.
A novel method to produce small droplets from large nozzles
Authors: Castrejón-Pita A. A. , Castrejón-Pita J. R. , Martin G. D.
Published: November 2012

This work presents a new method to generate droplets with diameters significantly smaller than the nozzle from which they emerge. The electrical waveform used to produce the jetting consists of a single square negative pulse. The negative edge of the pressure wave pulls the meniscus in, overturning the surface in such a way that a cavity is created. This cavity is then forced to collapse under the action of the positive edge of the pressure wave. This violent collapse produces a thin jet that eventually breaks up and produces droplets. Four droplet generator prototypes that demonstrate the capabilities of this novel mechanism are described. It is also shown that the proposed mechanism extends the existing limits of the commonly accepted inkjet operating regime.
Chemical composition and bioethanol potential of different plant species found in Pacific Northwest conservation buffers
Authors: Kumar Deepak , Juneja Ankita , Hohenschuh William , Williams John D. , Murthy Ganti S.
Published: November 2012

Lands producing mixed lignocellulosic ethanol feedstocks may be able to produce more biomass with fewer resources than conventional monoculture crops, but lignocellulosic ethanol production processes and efficiencies can be highly dependent on feedstock composition. In this study, plants were collected from areas planted to simulate conservation buffers alongside stream channels within three common resource areas the interior Pacific Northwest. Two grasses (tall wheatgrass and alfalfa) and seven forb species (fiddleneck tarweed, dog fennel, kochia, downey brome, tall annual willowherb, prickly lettuce, and tumble mustard) commonly found in these buffers were examined to determine their chemical composition, potential bioethanol yields, and difficulties that may arise if they were to be harvested and processed in a single facility. Potential ethanol yields calculated on the basis of sugar monomer composition in the biomass ranged from 181.5 to 316.5 l/dry ton of biomass. Significant differences were noted in terms of structural sugars (cellulose 19%–33% w/w; hemicellulose 14%–26% w/w), lignin (10%–18% w/w), extractives (20%–40% w/w), and ash content (4.0%–13.8% w/w). These composition variations could vary the processing efficiency in terms of sugar recovery and eventual ethanol production yield.
Atomistic simulation of tunneling magnetoresistance using extended Hückel theory
Authors: Roy Arunanshu M. , Nikonov Dmitri E. , Young Ian A.
Published: November 2012

Atomistic simulations of magnetic tunnel junctions are performed using the extended Hückel theory and non equilibrium Green's function formalism. The effect of Fermi level pinning and the corresponding change in the tunnelling barrier height on the junction resistance and magnetoresistance ratio is studied. An approximate approach to the treatment of alloyed ferromagnet bandstructure is proposed and the effect of Fe and Co fractions in the ferromagnetic electrodes is determined.
Excitation energies from extended random phase approximation employed with approximate one- and two-electron reduced density matrices
Authors: Chatterjee Koushik , Pernal Katarzyna
Published: November 2012

Starting from Rowe's equation of motion we derive extended random phase approximation (ERPA) equations for excitation energies. The ERPA matrix elements are expressed in terms of the correlated ground state one- and two-electron reduced density matrices, 1- and 2-RDM, respectively. Three ways of obtaining approximate 2-RDM are considered: linearization of the ERPA equations, obtaining 2-RDM from density matrix functionals, and employing 2-RDM corresponding to an antisymmetrized product of strongly orthogonal geminals (APSG) ansatz. Applying the ERPA equations with the exact 2-RDM to a hydrogen molecule reveals that the resulting \documentclass[12pt]{minimal}\begin{document}$^1\Sigma _g^+$\end{document}Σg+1 excitation energies are not exact. A correction to the ERPA excitation operator involving some double excitations is proposed leading to the ERPA2 approach, which employs the APSG one- and two-electron reduced density matrices. For two-electron systems ERPA2 satisfies a consistency condition and yields exact singlet excitations. It is shown that 2-RDM corresponding to the APSG theory employed in the ERPA2 equations yields excellent singlet excitation energies for Be and LiH systems, and for the N2 molecule the quality of the potential energy curves is at the coupled cluster singles and doubles level. ERPA2 nearly satisfies the consistency condition for small molecules that partially explains its good performance.
The application of the fast, multi-hit, pixel imaging mass spectrometry sensor to spatial imaging mass spectrometry
Authors: Brouard M. , Halford E. , Lauer A. , Slater C. S. , Winter B. , Yuen W. H. , John J. J. , Hill L. , Nomerotski A. , Clark A. , Crooks J. , Sedgwick I. , Turchetta R. , Lee J. W. L. , Vallance C. , Wilman E.
Published: November 2012

Imaging mass spectrometry is a powerful technique that allows chemical information to be correlated to a spatial coordinate on a sample. By using stigmatic ion microscopy, in conjunction with fast cameras, multiple ion masses can be imaged within a single experimental cycle. This means that fewer laser shots and acquisition cycles are required to obtain a full data set, and samples suffer less degradation as overall collection time is reduced. We present the first spatial imaging mass spectrometry results obtained with a new time-stamping detector, named the pixel imaging mass spectrometry (PImMS) sensor. The sensor is capable of storing multiple time stamps in each pixel for each time-of-flight cycle, which gives it multi-mass imaging capabilities within each pixel. A standard velocity-map ion imaging apparatus was modified to allow for microscope mode spatial imaging of a large sample area (approximately 5 × 5 mm2). A variety of samples were imaged using PImMS and a conventional camera to determine the specifications and possible applications of the spectrometer and the PImMS camera.
Growth and characterization of single crystal rocksalt LaAs using LuAs barrier layers
Authors: Krivoy E. M. , Rahimi S. , Nair H. P. , Salas R. , Maddox S. J. , Ironside D. J. , Jiang Y. , Dasika V. D. , Ferrer D. A. , Kelp G. , Shvets G. , Akinwande D. , Bank S. R.
Published: November 2012

We demonstrate the growth of high-quality, single crystal, rocksalt LaAs on III-V substrates; employing thin well-behaved LuAs barriers layers at the III-V/LaAs interfaces to suppress nucleation of other LaAs phases, interfacial reactions between GaAs and LaAs, and polycrystalline LaAs growth. This method enables growth of single crystal epitaxial rocksalt LaAs with enhanced structural and electrical properties. Temperature-dependent resistivity and optical reflectivity measurements suggest that epitaxial LaAs is semimetallic, consistent with bandstructure calculations in literature. LaAs exhibits distinct electrical and optical properties, as compared with previously reported rare-earth arsenide materials, with a room-temperature resistivity of ∼459 μΩ-cm and an optical transmission window >50% between ∼3-5 μm.
Gas temperature measurements inside a hot wall chemical vapor synthesis reactor
Authors: Notthoff Christian , Schilling Carolin , Winterer Markus
Published: November 2012

One key but complex parameter in the chemical vapor synthesis (CVS) of nanoparticles is the time temperature profile of the gas phase, which determines particle characteristics such as size (distribution), morphology, microstructure, crystal, and local structure. Relevant for the CVS process and for the corresponding particle characteristics is, however, not the T(t)-profile generated by an external energy source such as a hot wall or microwave reactor but the temperature of the gas carrying reactants and products (particles). Due to a complex feedback of the thermodynamic and chemical processes in the reaction volume with the external energy source, it is very difficult to predict the real gas phase temperature field from the externally applied T(t)-profile. Therefore, a measurement technique capable to determine the temperature distribution of the gas phase under process conditions is needed. In this contribution, we demonstrate with three proof of principle experiments the use of laser induced fluorescence thermometry to investigate the CVS process under realistic conditions.
Photoelectron spectroscopy and density functional theory studies on the uridine homodimer radical anions
Authors: Jae Ko Yeon , Storoniak Piotr , Wang Haopeng , Bowen Kit H. , Rak Janusz
Published: November 2012

We report the photoelectron spectrum (PES) of the homogeneous dimer anion radical of uridine, (rU)2•−. It features a broad band consisting of an onset of ∼1.2 eV and a maximum at the electron binding energy (EBE) ranging from 2.0 to 2.5 eV. Calculations performed at the B3LYP/6-31++G** level of theory suggest that the PES is dominated by dimeric radical anions in which one uridine nucleoside, hosting the excess charge on the base moiety, forms hydrogen bonds via its O8 atom with hydroxyl of the other neutral nucleoside's ribose. The calculated adiabatic electron affinities (AEAGs) and vertical detachment energies (VDEs) of the most stable homodimers show an excellent agreement with the experimental values. The anionic complexes consisting of two intermolecular uracil-uracil hydrogen bonds appeared to be substantially less stable than the uracil-ribose dimers. Despite the fact that uracil-uracil anionic homodimers are additionally stabilized by barrier-free electron-induced proton transfer, their relative thermodynamic stabilities and the calculated VDEs suggest that they do not contribute to the experimental PES spectrum of (rU)2•−.
Electronic absorptions of the benzylium cation
Authors: Dryza Viktoras , Chalyavi Nahid , Sanelli Julian A. , Bieske Evan J.
Published: November 2012

The electronic transitions of the benzylium cation (Bz+) are investigated over the 250–550 nm range by monitoring the photodissociation of mass-selected C7H7+-Arn (n = 1, 2) complexes in a tandem mass spectrometer. The Bz+-Ar spectrum displays two distinct band systems, the S1←S0 band system extending from 370 to 530 nm with an origin at 19 067 ± 15 cm−1, and a much stronger S3←S0 band system extending from 270 to 320 nm with an origin at 32 035 ± 15 cm−1. Whereas the S1←S0 absorption exhibits well resolved vibrational progressions, the S3←S0 absorption is broad and relatively structureless. Vibronic structure of the S1←S0 system, which is interpreted with the aid of time-dependent density functional theory and Franck-Condon simulations, reflects the activity of four totally symmetric ring deformation modes (ν5, ν6, ν9, ν13). We find no evidence for the ultraviolet absorption of the tropylium cation, which according to the neon matrix spectrum should occur over the 260 – 275 nm range [A. Nagy, J. Fulara, I. Garkusha, and J. Maier, Angew. Chem., Int. Ed. 50, 3022 (2011)]10.1002/anie.201008036.
Electric field induced transition from electron—only to hole-only conduction in polymer—fullerene metal-insulator-metal devices
Authors: Chiguvare Zivayi
Published: November 2012

We studied charge injection and transport mechanisms in blends of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methylester (PCBM), by analysing dark, temperature dependent current-voltage characteristics of the P3HT:PCBM blend thin films sandwiched between aluminium electrodes in a metal/insulator/metal (MIM) configuration. We show that by applying appropriate electric fields, it is possible to switch from electron-only conduction to hole-only conduction in a single Al/P3HT:PCBM/Al device and present a general method of interpreting Fowler-Nordheim plots of MIM devices with pronounced non-linear characteristics by dividing them into several regions based on physical origins. We affirm that electrons can be selectively transported through the lowest unoccupied molecular orbital of PCBM at low applied voltages and low temperatures; and alternatively holes can be transported through the highest occupied molecular orbital of P3HT at higher applied voltages and high temperature, within a single device.
Nonadiabatic ab initio molecular dynamics of photoisomerization in bridged azobenzene
Authors: Gao Ai-Hua , Li Bin , Zhang Pei-Yu , Han Ke-Li
Published: November 2012

The photoisomerization mechanisms of bridged azobenzene are investigated by means of surface hopping dynamics simulations based on the Zhu-Nakamura theory. In the geometry optimizations and potential energy surface calculations, four minimum-energy conical intersections between the ground state and the lowest excited state are found to play important roles in the trans-cis and cis-trans isomerization processes. The trans-cis photoisomerization proceeds through two minimum-energy conical intersections. Ultrafast pedal motion of the N atoms and twisting of phenyl rings around their N–C bonds allows the molecule to move to a minimum-energy conical intersection, after which surface hopping from S1 to S0 occurs. In the S0 state, further rotation occurs around the N=N bond and two N–C bonds until the azo moiety and phenyl rings complete their isomerization. Finally, the cis form is achieved by subsequent adjustment of the ethylene bridge. In the cis-trans photodynamics, there is one rotational pathway, in the middle of which two CIs are responsible for the surface hopping to the S0 state. After the nonadiabatic transition, the molecule reaches the trans form through a barrierless pathway and the two phenyl rings and the additional bridge complete their reorientation almost at the same time.
Pressure and partial wetting effects on superhydrophobic friction reduction in microchannel flow
Authors: Kim Tae Jin , Hidrovo Carlos
Published: November 2012

Friction reduction in microchannel flows can help alleviate the inherently taxing pumping power requirements associated with the dimensions involved. One possible way of achieving friction reduction is through the introduction of surface microtexturing that can lead to a superhydrophobic Cassie-Baxter state. The Cassie-Baxter state is characterized by the presence of air pockets within the surface microtexturing believed to act as an effective “shear free” (or at least shear reduced) layer, decreasing the overall friction characteristics of the surface. Most work in this area has concentrated on optimizing the surface microtexturing geometry to maximize the friction reduction effects and overall stability of the Cassie-Baxter state. However, less attention has been paid to the effects of partially wetted conditions induced by pressure and the correlation between the liquid-gas interface location within the surface microtexturing and the microchannel flow characteristics. This is mainly attributed to the difficulty in tracking the interface shape and location within the microtexturing in the typical top-down view arrangements used in most studies. In this paper, a rectangular microchannel with regular microtexturing on the sidewalls is used to visualize and track the location of the air-water interface within the roughness elements. While visually tracking the wetting conditions in the microtextures, pressure drops versus flow rates for each microchannel are measured and analyzed in terms of the non-dimensional friction coefficient. The frictional behavior of the Poiseuille flow suggests that (1) the air-water interface more closely resembles a no-slip boundary rather than a shear-free one, (2) the friction is rather insensitive to the degree of microtexturing wetting, and (3) the fully wetted (Wenzel state) microtexturing provides lower friction than the non-wetted one (Cassie state), in corroboration with observations (1) and (2).
Structural study of Bi2Sr2CaCu2O8+δ exfoliated nanocrystals
Authors: Lupascu A. , Feng Renfei , Sandilands L. J. , Nie Zixin , Baydina V. , Gu Genda , Ono Shimpei , Ando Yoichi , Kwok D. C. , Lee N. , Cheong S.-W. , Burch K. S. , Kim Young-June
Published: November 2012

We demonstrate that structural and spectroscopic information can be obtained on exfoliated nanocrystals as thin as 6 nm. This can be achieved by using a combination of micro X-ray fluorescence (μXRF), micro X-ray absorption near-edge spectroscopy (μXANES), and X-ray microdiffraction (μXRD) techniques. Highly focused, tunable X-ray beams available at synchrotron sources enable one to use these non-invasive characterization tools to study exfoliated samples on a variety of substrates. As an example, we focused on exfoliated nanocrystals of the high temperature superconductor Bi2Sr2CaCu2O8+δ. μXRF is used to locate the sample of desired thickness; μXANES and μXRD are used to obtain electronic and structural information, respectively. We find that the “4.7b” structural modulation, characteristic of the bulk crystals, is drastically suppressed for exfoliated crystals thinner than 60 nm.
Crystal structure and epitaxy of Bi2Te3 films grown on Si
Authors: Park Jihwey , Soh Yeong-Ah , Aeppli G. , Bland S. R. , Zhu Xie-Gang , Chen Xi , Xue Qi-Kun , Grey Francois
Published: November 2012

We report comprehensive x-ray diffraction studies of the crystal structure and epitaxy of thin films of the topological insulator Bi2Te3 grown on Si (1 1 1). The films are single crystals of high crystalline quality, which strongly depend on that of their substrates, with in-plane epitaxial relationships of Bi2Te3 [2 1 −3 0] ‖ Si [1 −1 0] and Bi2Te3 [0 1 −1 0] ‖ Si [1 1 −2] along which the lattices of 1 × 3 Bi2Te3 and 2 × 2 Si supercells are well matched. As the samples age, we observe loss of crystalline Bi2Te3 film thickness accompanied with roughening of the crystalline interfaces, formation of new crystalline phases as well as compositional and structural modification of the Si substrate, consistent with the diffusion of Te into the Si substrate.
Green function solution of a second-order partial differential equation and conductivity of thin films
Authors: Ünal B.
Published: November 2012

Correct form of the Green function G of the Schrödinger equation is developed for a thin metallic film of thickness d which contains infinitesimally weak volume and surface scatterers. Conductivity σ of the film is obtained from the imaginary part of the self-energy Σ appearing in the average G and increases smoothly with d and that density of states is not staircaselike as contrast to the usual. Examination of σ in terms of d agrees well with the experiment.