bluuebunny/crossref_metadata_2025 huggingface dataset:
On the structure of plasma liners for plasma jet induced magnetoinertial fusion
Authors: Kim Hyoungkeun , Zhang Lina , Samulyak Roman , Parks Paul
Published: February 2013

The internal structure and self-collapse properties of plasma liners, formed by the merger of argon plasma jets, have been studied via 3-dimensional numerical simulations using the FronTier code. We have shown that the jets merger process is accomplished through a cascade of oblique shock waves that heat the liner and reduce its Mach number. Oblique shock waves and the adiabatic compression heating have led to the 10 times reduction of the self-collapse pressure of a 3-dimensional argon liner compared to a spherically symmetric liner with the same pressure and density profiles at the merging radius. We have also observed a factor of 10 variations of pressure and density in the leading edge of the liner along spherical surfaces close to the interaction with potential plasma targets. Such a non-uniformity of imploding plasma liners presents problems for the stability of targets during compression.
Stability of passive locomotion in inviscid wakes
Authors: Oskouei Babak G. , Kanso Eva
Published: February 2013

We consider the passive locomotion of rigid bodies in inviscid point-vortex wakes. This work is motivated by a common belief that live and inanimate objects may extract energy from unsteady flows for locomotory advantages. Studies on energy extraction from unsteady flows focus primarily on energy efficiency. Besides efficiency, a fundamental aspect of energy extraction for locomotion purposes is stability of motion. Here, we propose idealized wake models using periodically generated point vortices to emulate shedding of vortices from an un-modeled moving or stationary object. We assess the stability of these point-vortex wakes and find that they are stable for a range of periods, unlike the von Kármán street model which is mainly unstable. We then investigate the dynamics of a rigid body submerged in such wakes. In particular, we calculate periodic trajectories where the rigid body “swims” passively against the flow by extracting energy from the ambient vortices. All the periodic trajectories we find are unstable. The largest instabilities reported are for elliptic bodies where rotational effects play a role in destabilizing their motion. Within the context of this model, we conclude that passive locomotion of rigid bodies in inviscid wakes is unstable. Questions as to whether passive stability can be achieved when accounting for fluid viscosity and body elasticity remain open.
Low-temperature indium-bonded alkali vapor cell for chip-scale atomic clocks
Authors: Straessle R. , Pellaton M. , Affolderbach C. , Pétremand Y. , Briand D. , Mileti G. , de Rooij N. F.
Published: February 2013

A low-temperature sealing technique for micro-fabricated alkali vapor cells for chip-scale atomic clock applications is developed and evaluated. A thin-film indium bonding technique was used for sealing the cells at temperatures of ≤140 °C. These sealing temperatures are much lower than those reported for other approaches, and make the technique highly interesting for future micro-fabricated cells, using anti-relaxation wall coatings. Optical and microwave spectroscopy performed on first indium-bonded cells without wall coatings are used to evaluate the cleanliness of the process as well as a potential leak rate of the cells. Both measurements confirm a stable pressure inside the cell and therefore an excellent hermeticity of the indium bonding. The double-resonance measurements performed over several months show an upper limit for the leak rate of 1.5 × 10−13 mbar·l/s. This is in agreement with additional leak-rate measurements using a membrane deflection method on indium-bonded test structures.
NMR relaxation study of water dynamics in superparamagnetic iron-oxide-loaded vesicles
Authors: Chen Yu-Wen , Hsieh Chu-Jung , Lin Chao-Min , Hwang Dennis W.
Published: February 2013

Superparamagnetic iron oxide (SPIO) nanoparticles have been introduced as contrast agents for clinical applications in magnetic resonance imaging. Recently, SPIO has been also used for tracking cells. However, NMR relaxation of water molecules behaves differently in a SPIO solution and SPIO-loaded cells. In this study, we used water-in-oil-in-water double emulsions to mimic cellular environments. The MR relaxation induced by the SPIO-loaded vesicles and SPIO solution indicates that T2* is sensitive to the iron concentration alone, and the behavior was very similar in both SPIO-loaded vesicles and SPIO solution. However, T2 relaxation of water in SPIO-loaded vesicles was faster than that in a SPIO solution. In addition, the contribution of water inside and outside the vesicles was clarified by replacing H2O with D2O, and water inside the vesicles was found to cause a nonlinear iron concentration dependency. The studied dilution revealed that vesicle aggregation undergoes a structural transition upon dilution by a certain amount of water. R2* relaxation is sensitive to this structural change and shows an obvious nonlinear iron concentration dependency when the SPIO loading is sufficiently high. Random walk simulations demonstrated that in the assumed model, the vesicles aggregate structures causing the differences between R2* and R2 relaxation of water in vesicles in the presence of SPIO particles.
Sample dispersion in isotachophoresis with Poiseuille counterflow
Authors: Bhattacharyya Somnath , Gopmandal Partha P. , Baier Tobias , Hardt Steffen
Published: February 2013

A particular mode of isotachophoresis (ITP) employs a pressure-driven flow opposite to the sample electromigration direction in order to anchor a sample zone at a specific position along a channel or capillary. We investigate this situation using a two-dimensional finite-volume model based on the Nernst-Planck equation. The imposed Poiseuille flow profile leads to a significant dispersion of the sample zone. This effect is detrimental for the resolution in analytical applications of ITP. We investigate the impact of convective dispersion, characterized by the area-averaged width of a sample zone, for various values of the sample Péclet-number, as well as the relative mobilities of the sample and the adjacent electrolytes. A one-dimensional model for the area-averaged concentrations based on a Taylor-Aris-type effective axial diffusivity is shown to yield good agreement with the finite-volume calculations. This justifies the use of such simple models and opens the door for the rapid simulation of ITP protocols with Poiseuille counterflow.
Planar Hall resistance ring sensor based on NiFe/Cu/IrMn trilayer structure
Authors: Sinha Brajalal , Quang Hung Tran , Sri Ramulu Torati , Oh Sunjong , Kim Kunwoo , Kim Dong-Young , Terki Ferial , Kim CheolGi
Published: February 2013

We have investigated the sensitivity of a planar Hall resistance sensor as a function of the ring radius in the trilayer structure Ta(3)/IrMn(10)/Cu(0.2)/NiFe(10)/Ta(3) (nm). The diagonal components of magnetoresistivity tensor in rectangular prism corresponding to anisotropic magnetoresistance are few ten times larger than that of off-diagonal component corresponding to planar Hall resistance. However, it is noteworthy that the resultant contribution is governed by the off-diagonal components due to the cancellation of diagonal components in the self-balanced bridge configuration. Both the experimental and theoretical results show that the sensitivity varies linearly with the ring radius. In multi-ring architecture, the circumference can be increased to a limit, which consequently enhances sensitivity. We found the sensitivity of the investigated 7-rings planar Hall to be more than 600 μV/Oe.
Determination of the inner diameter of a double-walled carbon nanotube from its Raman spectra
Authors: Basirjafari Sedigheh , Esmaielzadeh Khadem Siamak , Malekfar Rasoul
Published: February 2013

In this paper, an exact formula is obtained for the inner diameter of double-walled carbon nanotube (DWCNT) as a function of its higher radial breathing mode (RBM) frequency, using the symbolic package of maple software. Its outer diameter is obtained from the inner diameter formula by considering the constant interlayer spacing between two tubes of DWCNT. For this purpose, DWCNT is considered as double concentric elastic thin cylindrical shells, which are coupled through the van der Waals (vdW) forces between two tubes. Lennard-Jones potential is used to calculate the vdW forces between tubes. The advantage of this analytical approach is that in the double concentric elastic shell model all degrees of freedom in the vibrational analysis of DWCNTs are considered. To demonstrate the accuracy of this work, the relationship between RBM frequency of a single-walled carbon nanotube and its radius is deduced from the DWCNT formula that is well consistent with other publications. To illustrate the application of this approach, the diameters of DWCNTs are obtained from their known RBM frequencies which show an excellent agreement with the available experimental results. Also, the influence of changing the geometrical and mechanical parameters of a DWCNT on its RBM frequencies has been investigated.
Photo-induced electron detachment of protein polyanions in the VUV range
Authors: Brunet Claire , Antoine Rodolphe , Dugourd Philippe , Canon Francis , Giuliani Alexandre , Nahon Laurent
Published: February 2013

Biomolecular polyanions mainly relax by electron emission after UV excitation. Here, we study photodetachment of protein polyanions in the 6–16 eV VUV range by coupling a linear quadrupole ion trap with a synchrotron beamline. Gas-phase VUV action spectra of electrospray-produced multiply deprotonated insulin (5.6 kDa) and myoglobin (16.7 kDa) proteins are reported, which significantly increases the amount of data available on the optical response of proteins in the VUV. The influence of the protein charge and oxidation state upon the electron detachment efficiency is discussed. For small protein such as insulin, it appears that higher charge states produce higher detachment yields. Investigations on oxidized species show that the nature of the groups bearing the negative charges has an influence on the yields. For larger proteins, comparison of two forms of myoglobin clearly indicate that the three-dimensional structure does not impact much on the shape and the magnitude of the photodetachment spectra, in spite of a slight shift for the first electronic excited states.
Oblique shock structures formed during the ablation phase of aluminium wire array z-pinches
Authors: Swadling G. F. , Lebedev S. V. , Niasse N. , Chittenden J. P. , Hall G. N. , Suzuki-Vidal F. , Burdiak G. , Harvey-Thompson A. J. , Bland S. N. , De Grouchy P. , Khoory E. , Pickworth L. , Skidmore J. , Suttle L.
Published: February 2013

A series of experiments has been conducted in order to investigate the azimuthal structures formed by the interactions of cylindrically converging plasma flows during the ablation phase of aluminium wire array Z pinch implosions. These experiments were carried out using the 1.4 MA, 240 ns MAGPIE generator at Imperial College London. The main diagnostic used in this study was a two-colour, end-on, Mach-Zehnder imaging interferometer, sensitive to the axially integrated electron density of the plasma. The data collected in these experiments reveal the strongly collisional dynamics of the aluminium ablation streams. The structure of the flows is dominated by a dense network of oblique shock fronts, formed by supersonic collisions between adjacent ablation streams. An estimate for the range of the flow Mach number (M = 6.2-9.2) has been made based on an analysis of the observed shock geometry. Combining this measurement with previously published Thomson Scattering measurements of the plasma flow velocity by Harvey-Thompson et al. [Physics of Plasmas 19, 056303 (2012)] allowed us to place limits on the range of the Z¯Te of the plasma. The detailed and quantitative nature of the dataset lends itself well as a source for model validation and code verification exercises, as the exact shock geometry is sensitive to many of the plasma parameters. Comparison of electron density data produced through numerical modelling with the Gorgon 3D MHD code demonstrates that the code is able to reproduce the collisional dynamics observed in aluminium arrays reasonably well.
Rayleigh-Bénard convection for viscoplastic fluids
Authors: Darbouli Mohamed , Métivier Christel , Piau Jean-Michel , Magnin Albert , Abdelali Ahmed
Published: February 2013

The influence of rheological and interfacial properties of yield stress fluids is investigated on the onset of the Rayleigh-Bénard convection. Different Carbopol® (B.F. Goodrich) gels are used in a circular cell for Rayleigh-Bénard experimental setup. The influence of the boundary conditions is also investigated by controlling either slip or no-slip conditions. The onset of thermoconvection is shown by measuring temperature differences and also by using shadowgraph flow visualization. Experimental results show that convection occurs in the range of our experiments. Considering Carbopol gels as elasto-plastic materials with a yield stress τy, a generalized Rayleigh number is obtained: Rag = Y−1, with Y the yield number, which represents the balance between the yield stress of the gel and the buoyancy effects. The results show that the Rayleigh number is proportional to d, the height of the setup, and that the control parameter is the yield number at the onset of convection. Critical values of Y−1 have been determined for slip conditions \documentclass[12pt]{minimal}\begin{document}$1/Y_c^S\approx 40$\end{document}1/YcS≈40 as well as for no-slip conditions \documentclass[12pt]{minimal}\begin{document}$1/Y_c^{NS}\approx 80$\end{document}1/YcNS≈80. It highlights that the change in surface conditions affect significantly the critical conditions.
Communication: Designed diamond ground state via optimized isotropic monotonic pair potentials
Authors: Marcotte É. , Stillinger F. H. , Torquato Salvatore
Published: February 2013

We apply inverse statistical-mechanical methods to find a simple family of optimized isotropic, monotonic pair potentials (that may be experimentally realizable) whose classical ground state is the diamond crystal for the widest possible pressure range, subject to certain constraints (e.g., desirable phonon spectra). We also ascertain the ground-state phase diagram for a specific optimized potential to show that other crystal structures arise for pressures outside the diamond stability range. Cooling disordered configurations interacting with our optimized potential to absolute zero frequently leads to the desired diamond crystal ground state, revealing that the capture basin for the global energy minimum is large and broad relative to the local energy minima basins.
Gyroaverage effects on chaotic transport by drift waves in zonal flows
Authors: Martinell Julio J. , del-Castillo-Negrete Diego
Published: February 2013

Finite Larmor radius (FLR) effects on E × B test particle chaotic transport in the presence of zonal flows is studied. The FLR effects are introduced by the gyro-average of a simplified E × B guiding center model consisting of the linear superposition of a non-monotonic zonal flow and drift waves. Non-monotonic zonal flows play a critical role on transport because they exhibit robust barriers to chaotic transport in the region(s) where the shear vanishes. In addition, the non-monotonicity gives rise to nontrivial changes in the topology of the orbits of the E × B Hamiltonian due to separatrix reconnection. The present study focuses on the role of FLR effects on these two signatures of non-monotonic zonal flows: shearless transport barriers and separatrix reconnection. It is shown that, as the Larmor radius increases, the effective zonal flow profile bifurcates and multiple shearless regions are created. As a result, the topology of the gyro-averaged Hamiltonian exhibits very complex separatrix reconnection bifurcations. It is also shown that FLR effects tend to reduce chaotic transport. In particular, the restoration of destroyed transport barriers is observed as the Larmor radius increases. A detailed numerical study is presented on the onset of global chaotic transport as function of the amplitude of the drift waves and the Larmor radius. For a given amplitude, the threshold for the destruction of the shearless transport barrier, as function of the Larmor radius, exhibits a fractal-like structure. The FLR effects on a thermal distribution of test particles are also studied. In particular, the fraction of confined particles with a Maxwellian distribution of gyroradii is computed, and an effective transport suppression is found for high enough temperatures.
Theoretical treatments of the bound-free contribution and experimental best practice in X-ray Thomson scattering from warm dense matter
Authors: Mattern Brian A. , Seidler Gerald T.
Published: February 2013

By comparison with high-resolution synchrotron x-ray experimental results, we assess several theoretical treatments for the bound-free (core-electron) contribution to x-ray Thomson scattering (i.e., also known as nonresonant inelastic x-ray scattering). We identify an often overlooked source of systematic error in the plane-wave form factor approximation (PWFFA) used in the inference of temperature, ionization state, and free electron density in some laser-driven compression studies of warm dense matter. This error is due to a direct violation of energy conservation in the PWFFA. We propose an improved practice for the bound-free term that will be particularly relevant for XRTS experiments performed with somewhat improved energy resolution at the National Ignition Facility or the Linac Coherent Light Source. Our results raise important questions about the accuracy of state variable determination in XRTS studies, given that the limited information content in low-resolution XRTS spectra does not strongly constrain the models of electronic structure being used to fit the spectra.
Investigation of charge transfer and ionization in He-like systems (Li+, Be2+, B3+, C4+, N5+, O6+)-hydrogen atom collisions in Debye plasmas
Authors: Pandey M. K. , Lin Y.-C. , Ho Y. K.
Published: February 2013

The charge transfer and ionization cross sections have been calculated for He-like system (Li+, Be2+, B3+, C4+, N5+, O6+) and hydrogen atom collisions in Debye plasmas for energies ranging from 1 to 500 keV using the classical trajectory Monte Carlo method. Interactions of the active electrons with the projectile ions have been described by model potentials. Cross sections are determined in both screening and unscreening environments, and a comparative study between both environments has been carried out. In particular, an interesting feature of sudden increase in the ionization cross sections at lower velocities is also observed in all the systems like pandey et al. [M. K. Pandey et al., Phys. Plasmas 19, 062104 (2012)] calculations for O8+ + H collision. The feature of sudden increase in ionization cross sections at lower velocities and the effect of plasmas condition on it are explained in terms of the classical trajectory framework. We have found the cross sections for both capture and ionization are dependence on Debye screening lengths throughout the collision energies range, but are particularly pronounced at low projectile collisions energies. The calculated cross sections for the unscreened case are found in reasonable agreement with available experimental and theoretical results.
Intensity dependent spectral features in high harmonic generation
Authors: Ba Dinh Khuong , Hannaford Peter , Van Dao Lap
Published: February 2013

We study the influence of the driving laser intensity on the spectral features of high harmonic generation in a semi-infinite gas cell. The effects of the harmonic dipole phase and the dispersion phase mismatches induced by the ionized medium during the harmonic generation process are revealed and the interplay between the macroscopic response and the single-atom response is discussed. We consider the conditions for generation of a narrow bandwidth, bright, and highly coherent high harmonic source.
Non-periodicity of peak-to-peak distances in x-ray diffraction spectrums from perfect superlattices
Authors: Sankowska I. , Domagala J. Z. , Yefanov O. M. , Jasik A. , Kubacka-Traczyk J. , Regiński K. , Seeck O. H.
Published: February 2013

X-ray diffraction investigations of type II InAs/GaSb superlattice on a GaSb(001) substrate are presented. The wide range of diffraction angles (2θ/ω scans) covering 002 and 004 reflections was examined at Petra III synchrotron. The angular region between 002 and 004 reflections was the most interesting part of the measured diffraction profile. In this region, a non-coincidence of superlattice satellite peaks belonging to these two reflections is observed. The multiple-beam dynamical diffraction approach was used for correct simulation of the observed diffraction profile.
Investigation of the opulent porosity for better performance of dye-sensitized solar cell
Authors: Jyoti Divya , Mohan Devendra , Dhar Rakesh
Published: February 2013

The presented research work is an effort to optimize porosity of TiO2 film to get enhanced performance of dye-sensitized solar cell. A novel and economic technique is presented to control the porosity. Poroellipsometry was used to measure porosity of the films. A comparison between microporous (P = 22.3), mesoporous (P = 39.1), and macroporous (63.6) structures has been made by obtaining current density-voltage (JV) characteristics and incident photon to current conversion efficiency curves. It has been found that morphology of mesoporous films with porosity P = 39.1 is best suited for dye-sensitized solar cells. The results are in well agreement with theoretical predictions regarding porosity.
Lanthanum halide nanoparticle scintillators for nuclear radiation detection
Authors: Guss Paul , Guise Ronald , Yuan Ding , Mukhopadhyay Sanjoy , O'Brien Robert , Lowe Daniel , Kang Zhitao , Menkara Hisham , Nagarkar Vivek V.
Published: February 2013

Nanoparticles with sizes <10 nm were fabricated and characterized for their nanocomposite radiation detector properties. This work investigated the properties of several nanostructured radiation scintillators, in order to determine the viability of using scintillators employing nanostructured lanthanum trifluoride. Preliminary results of this investigation are consistent with the idea that these materials have an intrinsic response to nuclear radiation that may be correlated to the energy of the incident radiation.
Extension of thickness-dependent dielectric breakdown law on adiabatically compressed ferroelectric materials
Authors: Shkuratov Sergey I. , Baird Jason , Talantsev Evgueni F.
Published: February 2013

It is experimentally found that the Eb(d) = γ · d−ξ law describing the thickness-dependent breakdown electric field for solid dielectrics at ambient conditions can be extended for dielectrics in other thermodynamic states. It follows from the experimental results reported herein that the breakdown field, Eb(d), of Pb(Zr0.95Ti0.05)O3 (PZT 95/5) and Pb(Zr0.52Ti0.48)O3 (PZT 52/48) ferroelectrics subjected to explosive adiabatic compression obeys the above-mentioned law in a wide range of voltages, up to 150 kV.
Giant self-biased magnetoelectric coupling in co-fired textured layered composites
Authors: Yan Yongke , Zhou Yuan , Priya Shashank
Published: February 2013

Co-fired magnetostrictive/piezoelectric/magnetostrictive laminate structure with silver inner electrode was synthesized and characterized. We demonstrate integration of textured piezoelectric microstructure with the cost-effective low-temperature co-fired layered structure to achieve strong magnetoelectric coupling. Using the co-fired composite, a strategy was developed based upon the hysteretic response of nickel-copper-zinc ferrite magnetostrictive materials to achieve peak magnetoelectric response at zero DC bias, referred as self-biased magnetoelectric response. Fundamental understanding of self-bias phenomenon in composites with single phase magnetic material was investigated by quantifying the magnetization and piezomagnetic changes with applied DC field. We delineate the contribution arising from the interfacial strain and inherent magnetic hysteretic behavior of copper modified nickel-zinc ferrite towards self-bias response.
Mechanically driven light-generator with high durability
Authors: Moon Jeong Soon , Song Seongkyu , Lee Soo-Keun , Choi Byeongdae
Published: February 2013

Mechanically activated luminescence from solids (mechanoluminescence) is a classical optical phenomenon induced in a substance when stressed or cleaved. However, no practical application has been realized due to its low luminescent intensity and lack of reproducibility. We demonstrate highly bright and durable mechanoluminescent flexible composite films with a brightness of ∼120 cd/m2 and durability over ∼100 000 repeated mechanical stresses by using a combination of copper-doped zinc sulfide (ZnS:Cu) particles and polydimethylsiloxane. Furthermore, the possibility of mechanoluminescent color-tuning by changing the repetitive stress rate on the composite films is also suggested. These findings can open a window for developing smart systems and opto-mechanical devices.
Pressure-induced tetragonal-orthorhombic phase transitions in CeRuPO
Authors: Hirai S. , Kamihara Y. , Wakatsuki A. , Matoba M. , Mao W. L.
Published: February 2013

CeRuPO, a ferromagnetic Kondo lattice, undergoes two novel pressure-induced structural phase transitions. CeRuPO undergoes an isostructural transition to a collapsed tetragonal structure near 7.5 GPa. Since pressure suppresses the initial ferromagnetic ordering of Ce3+, our observation suggests a quantum critical point for CeRuPO near this pressure. The collapsed tetragonal phase transforms into an orthorhombic Cmma structure. This phase is isostructural with the low temperature phase of LaFeAsO, which is superconducting under high pressure. Since CeRuPO exhibits a similar relationship between the two phases of LaFeAsO, the collapsed tetragonal and orthorhombic phases of CeRuPO may adopt a novel magnetic ground state.
Why specific mixed solvent composition leads to appropriate film formation of composite during spin coating?
Authors: Ghosh S. S. , Zerwal A. P. , Bisen G. G. , Lonkar G. S. , Sali J. V. , Waman V. S. , Jadkar S. R.
Published: February 2013

In this paper, we explain why specific mixed solvent composition leads to appropriate film formation of composite (polymer: inorganic nanoparticle) during spin coating. As a typical case, P3HT:TiO2 film formation has been discussed by taking chloroform as good solvent for P3HT while ethanol, methanol, and 2-propanol are used as co-solvents for dispersing TiO2. Mixed solvent evaporation dynamics during film drying has been simulated to explain the experimental results. Present study can be immensely useful for selecting proper solvents and their initial ratio for blend film formation of a particular phase separation.
Mid-infrared surface plasmon resonance in zinc oxide semiconductor thin films
Authors: Sachet Edward , Losego Mark D. , Guske Joshua , Franzen Stefan , Maria Jon-Paul
Published: February 2013

Surface plasmon resonance (SPR) in semiconducting materials at mid-infrared (mid-IR) energies offers the potential for new plasmonic functionalities and integration schemes. Mainstream semiconductors are transparent to mid-IR energies, thus a tightly integrated monolithic package for SPR sensing becomes feasible. We report mid-IR surface plasmon resonance in zinc oxide as a model material for semiconductors with 4 × 1019 to 8 × 1019 cm−3 carriers. The surface plasmon modes were characterized using spectroscopic IR-ellipsometry and compared to a reflectivity simulation. The data confirm the feasibility of mid-IR SPR, show a generic ability for plasmon tuning, and demonstrate the predictive power of the reflectivity model.
A numerical study into the influence of quantum dot size on the sub-bandgap interband photocurrent in intermediate band solar cells
Authors: Mellor Alexander , Luque Antonio , Tobías Ignacio , Martí Antonio
Published: February 2013

A numerical study is presented of the sub-bandgap interband photon absorption in quantum dot intermediate band solar cells. Absorption coefficients and photocurrent densities are calculated for the valence band to intermediate band transitions using a four-band k·p method. It is found that reducing the quantum dot width in the plane perpendicular to the growth direction increases the photocurrent from the valence band to the intermediate-band ground state if the fractional surface coverage of quantum dots is conserved. This provides a path to increase the sub-bandgap photocurrent in intermediate band solar cells.
Dielectric study on two dynamic phases of 1-propanol confined in mesopores of MCM-41
Authors: Takahara Shuichi , Mori Kenji , Kittaka Shigeharu
Published: February 2013

Two dynamic phases were recognized on the 1-propanol molecules confined in MCM-41 with pore diameters d = 2.1, 2.4, 2.7 and 3.6 nm by dielectric measurements, in which two types of confined states of liquid were investigated: surface-adsorbed (sa) and pore-filled (pf) liquid. The dielectric measurements in the frequency range 103–107 Hz and temperature range 120–300 K showed that the molecular motions became slower in the following order: bulk, pf and sa liquid, which is the same order as for methanol and ethanol confined in MCM-41 reported previously. For pf samples, two relaxation components, which correspond to molecules near the pore surface and at the center of the pores, were observed separately. This is somewhat different from the behavior of methanol and ethanol confined as pf state in which two relaxation components were also detected but a clear separation between them was not observed. This implies that 1-propanol molecules near the pore wall interact weakly with those at the central part of the pores. For the MCM-41 sample with the smallest pore diameter (d = 2.1 nm), however, the dielectric spectra of the pf sample were very similar to those of the sa sample. That is, the dynamic motion of molecules in the pf sample was inhibited by narrow space surrounded by monolayer molecules similarly to that in the sa sample.
Form deviation and constraints on productivity
Authors: Löwenadler John
Published: February 2013

Issues concerning the nature of so-called ‘filler-gap’ constructions and the constraints on their acceptability in different languages have for a long time been at the center of the linguistic debate. In more recent years, claims have often been made that many or all constraints on such constructions can be explained in terms of processing restrictions, properties of information structure, or limits to attention. However, in the present paper I will argue that at least some of these constraints cannot be explained by such factors. Instead, I will claim that speakers’ judgements of acceptability could be negatively affected if the syntactic structure of a productively formed instance of a schematic construction is not sufficiently similar to the prototypical entrenched structure of the same construction. Importantly, this might happen whether the relevant form is a phonological pattern, or a pattern of schematic syntactic categories. I will show how the proposed principles have the potential to explain a number of well-known constraints which have generally not been regarded as related. More specifically, I will show how the principles can account for some striking similarities between filler-gap constraints in English and Swedish, as well as some unexpected differences. I will also argue that the filler-gap constraint referred to as the complementizer-gap effect can be explained by the same principles that are involved in phenomena such as restrictions on wanna-contraction in English and adjective defectiveness in Swedish. The analysis will be based on the constructional approaches of Croft (2001) and Verhagen (2009), and some crucial issues will concern the relationship between syntactic and phonological structure in a construction, and the notions of non-iconic constituency and gradient syntactic attachment.
Inflectional patterns as constructions
Authors: Beuls Katrien
Published: February 2013

Although often a painful and prolonged process, conjugating verbs correctly is essential when you try to master a foreign language. Verbs that exhibit an irregular conjugation paradigm, however, are often the verbs that occur most frequently in a language. The nature of inflectional morphemes and the mechanism for conjugating verbs have been the topic of debate for 25 years now. This has led to many different accounts of the problem, both in the field of descriptive linguistics as well as in a range of modeling approaches. The field of Construction Grammar has recently witnessed the theoretical work on Construction Morphology by Geert Booij (2010), but there has been no computational implementation that could test the theory on a large scale.

Using the framework of Fluid Construction Grammar (FCG), I investigate the grammar and morphological constructions that are needed to automatically conjugate the full paradigms of the 600 most frequently used verbs in Spanish. This paper reports a fully operational rule-based implementation of such a grammar and goes into the details of the constructions that support it. The results also show that morphological constructions are exemplary constructions since they combine two (or more) units (a stem and a suffix(es)) into a single meaningful unit (a conjugated verb form) that can be picked up by other discourse elements. Extensions towards embedding the conjugation constructions into a bigger grammar or automatically learning new morphological constructions remain the focus of future work.
English ants are digging holes in the Chinese levee
Authors: Xi Yan
Published: February 2013

The media have become a key site for the production and reproduction of language ideologies in modern societies. This is typically reflected in language ideological debates in 2010 in the Chinese media. In 2009, an article entitled “English ants are digging holes in the Chinese levee” got wide media coverage and aroused much controversy in the Chinese media in the following year. The crusade for linguistic purism ended with the promulgation of new regulations banning China’s media organizations and publishers from randomly mixing foreign languages with Chinese in publications. The present study aims to explore the inherent language ideologies naturalized in the debates of Chinese linguistic purism and various strategies adopted for the construction of the ideologies. The findings reveal that the ideology of “one nation and one language” and standard language ideology play an important role in the sociolinguistic imagination of a homogeneous Chinese society and protection of “pure” Chinese against English invasion. It is hoped that the present study will contribute to language ideology studies and shed new light on Chinese sociolinguistic studies.
Religion and artificial languages at the turn of the twentieth century
Authors: Garvía Roberto
Published: February 2013

What kinds of ideas and motivations drove artificial language promoters to face the skepticism, if not the mockery, of public opinion and advocate for one or another artificial language as the best solution to the communication predicament of the world? Were they purely instrumental ideas, or were they part and parcel of a distinctively religious agenda? This article contends that very much like other social and political movements of the turn of the twentieth century, such as Socialism, Nationalism, or Positivism, the longing for an international language, at least in the way it was conceived of by Ostwald and Zamenhof, also shares the basic characteristics of a secular religion: a message of meaning, a set of moral principles, and a message of salvation. More concretely, this article analyses Ostwald’s connection with the German Monist movement, and explains the role of Ido in his new religion, “Energism.” Similarly, it explores the connection between Zamenhof’s “Homaranism” and Reform Judaism, as developed by Abraham Geiger and Hermann Cohen.
Crafting sexual authenticity
Authors: Tabatabai Ahoo
Published: February 2013

In response to the renewed importance of authenticity in contemporary culture, academic studies of authenticity are flourishing. This work contributes to the scholarship of authenticity, by exploring how authenticity is constructed in narratives of sexual identity. This work examines the narratives of 32 women who were once partnered with women and identified as queer, lesbian or bisexual and subsequently became involved with men. Although the women in this study find themselves in a position with few available scripts to make sense of the change to a partner of a different gender, they work to construct their narratives around the central theme of consistency, while grappling with notions of agency. To create authentic sexual identities, they rely on several scripts, taking into account not only what they consider authentic but also what their audience will recognize as such. The women in this study maintain that both their attraction to women and their attraction to men are authentic. Both experiences are presented as connected to some sense of internal consistency.
Screwed up, but working on it
Authors: Thompson Riki
Published: February 2013

The turn to narrative as a form of therapy has become a common practice with individuals telling their stories in private and public forums in hopes of finding healing and recovery for a wide variety of mental health disorders. With the emergence of the internet and the proliferation of new media forms, narrative practices have evolved concurrently. An examination of the digitally mediated narratives I call e-stories, on mental health community websites can provide a window into how people use psychological concepts in narratives to do mental health work in everyday life (Edwards & Potter, 1992). This case study of the HealthyPlace online journal community shows how e-stories play a significant role in self-identity construction and ideological reproductive work in relation to mental illness and recovery. This research examines autobiographical introductions posted on twenty-eight journal homepages to explore how everyday people use psychotherapeutic coherence systems — lay versions of expert knowledge — to demonstrate expertise and authority while organizing experiences into a socially sharable narrative, characterizing self-identity in terms of illness and health simultaneously. These e-stories reveal the power of language to serve as a tool to negotiate community membership, reproduce ideologies about mental health and recovery, and employ narrative devices online to represent self-identities of people as “screwed up, but working on it.”
Narrativity and involvement in online consumer reviews
Authors: Vasquez Camilla
Published: February 2013

Drawing on recent work on digital narratives of personal experience in online genres such as email, social networking sites, and blogs, the present study explores narrative features in 100 online consumer reviews of hotels. Focusing on negative reviews, or “Rants,” from popular consumer travel platform, TripAdvisor, the article examines both canonical and genre-specific structural features of narratives, as well as some of the discursive resources used by online narrators to engage their audiences, and to draw them into their stories. Specifically, the study explores the use of story prefaces and related forms of second person address, represented speech and mental states, and deictic shifts, and suggests that narrative features such as these are useful in attracting the attention of an audience amidst a vast universe of online information.
Maneuvering between the individual and the social dimensions of narratives in a poor man’s discursive negotiation of stigma
Authors: Van De Mieroop Dorien
Published: February 2013

In current Western consumer societies, the poor are excluded and occupy stigmatized positions. By analyzing an interview with a poor man, I look at how stigma is discursively negotiated through the interplay between individual and social dimensions of narratives. First, the interviewee resists the interviewer’s ‘poor man’-category projection by setting up alternative groups. Second, he invokes and aligns with dominant discourses regarding the necessity to own consumer goods and find a work-life balance, by which he constructs the identity of an empowered “bricoleur” (cf Gabriel et al., 2010). These findings are then related to Goffman’s theory of stigma and information control (1963) and to the inextricable link between the performed nature of narratives, their individual and social dimensions and their local and global contexts.
On first-person narrative scholarship
Authors: Bochner Arthur P.
Published: February 2013

Social science writing can be construed as a form of discourse that puts meaning into motion. This article reviews the cultural conditions that inspired the burgeoning interest in autoethnography, the kinds of truth to which it aspires, and the opportunities it opens to invite readers into conversation with the possibilities of happiness in the presence of human suffering. Autoethnographies attempt to make social science something more than an end in itself.
Towards a multimethodological approach to identification of funds of identity, small stories and master narratives
Authors: Esteban-Guitart Moisès
Published: February 2013

The narrative turn in social and human sciences has led us to consider identity as a narrative phenomenon. We can classify most of the approaches that have been developed by the emphasis they put on the “subject” in the analysis. For some, the subject is the first person singular, who puts into order and constructs an internalized life story so as to give purpose and coherence to different life experiences. For others, the emphasis is on the relationship between the first and second person, the I-you, in conversational situations located in time and space. Still others argue that narratives — repertoires of behaviour and identity — are shared artefacts, of historical origin and their content is social, political and cultural (i.e., “we” and “they”). However, in all these approaches there is agreement that narratives of identity are cultural products, inseparable from the social, institutional, geographic and cultural forces which comprise what I call funds of identity. The aim of this article is to suggest the need to adopt a qualitative multi-methodological approach aimed at studying these funds of identity, thus complementing the general use of in-depth interviews.
Agency and dialogic tension in co-editing more preferred narratives
Authors: Strong Tom , Knight Sarah
Published: February 2013

As narrative therapists and researchers we are interested in how conversations invite co-authoring and co-editing possibilities to develop self-narratives preferred by our partners in dialogue. ‘Problem saturated stories’ acquire their dominance and self-defining plausibility through unquestioned personal and cultural conversations. Questions and responsive dialogues, however, can invite consideration and elaboration of previously implausible plotlines and discourses pertaining to self-narratives. Accordingly, we report on processes and outcomes from research conversations with volunteers who self-identified as having been sexually abused, and who joined Sarah in co-authoring and co-editing ‘small stories’ of healthy intimacy after the abuse.
Language learner stories and imagined identities
Authors: Early Margaret , Norton Bonny
Published: February 2013

In seeking to better understand English language learners and their imagined identities, which is the central focus of our article, scholars have drawn extensively on the work of Norton and colleagues. This work has foregrounded the language learner as a participating social agent with complex and changing identities. It is this agentive sense of self that is linked, in narratives, to larger socio-cultural and historical social practices. Our interest here lies particularly in the effects of migration on language learners. With this in mind, we advocate that classroom communities be fostered wherein a range of narrative identities, as sense-making practices, are respectfully harnessed as resources for learners of diverse linguistic histories, to create more socially just and responsive “possible worlds”.
Why narrative?
Authors: Bamberg Michael
Published: February 2013

This article addresses recent contestations of the role of narrative inquiry in the field of identity analysis and in qualitative inquiry more generally. In contrast to essentializing tendencies in the field of narrative inquiry (which have been contested under the headers of narrative exceptionalism, narrative imperialism, and narrative necessity), I am reiterating my proposal to theorize narrative inquiry as narrative practice (formerly ‘small story approach’) within which narratives and narrative inquiry present a more modest but thoroughly viable contribution.
Heart rate recovery after the 6 min walk test rather than distance ambulated is a powerful prognostic indicator in heart failure with reduced and preserved ejection fraction: a comparison with cardiopulmonary exercise testing
Authors: Cahalin Lawrence P. , Arena Ross , Labate Valentina , Bandera Francesco , Lavie Carl J. , Guazzi Marco
Published: February 2013

Aims

Heart rate recovery (HRR) appears to be a robust prognostic marker in heart failure (HF). When using the 6 min walk test (6MWT) in HF, distance ambulated is generally the reference prognostic variable. We hypothesized that HRR after the 6MWT would be a better prognostic measure than distance ambulated.

Methods and results

A 6MWT and cardiopulmonary exercise testing (CPX) were randomly performed in 258 HF patients [216 HF with reduced EF (HFrEF) and 42 HF preserved EF (HFpEF)], after which HRR was measured. HRR was defined as the difference between heart rate at peak exercise and 1 min following test termination. Patients were assessed for major cardiac events during a mean follow‐up period of 22.8 ± 22.1 months. There were 50 major cardiac events during the tracking period. Univariate Cox regression analysis results identified HRR after both the 6MWT and CPX as a significant (P < 0.001) predictor of adverse events. Multivariate Cox regression analysis revealed that dichotomized HRR after the 6MWT and CPX was the strongest predictor of survival (χ2 61.1 and 53.8, respectively; P < 0.001), with LVEF (residual χ2 6.1, P < 0.05) adding significant prognostic value to the 6MWT model and ventilatory efficiency (the VE/VCO2 slope) (residual χ2 6.6, P < 0 .05) adding significant prognostic value to the CPX model.

Conclusions

HRR after the 6MWT is a powerful prognosticator that performs similarly to HRR after maximal exercise. If confirmed in subsequent studies, 6MWT HRR should replace 6MWT distance as the reference criterion 6MWT measure to consider when grading cardiovascular risk in HF patients.