bluuebunny/crossref_metadata_2025 huggingface dataset:
Sulfur 1s near edge x-ray absorption fine structure spectroscopy of thiophenic and aromatic thioether compounds
Authors: Behyan Shirin , Hu Yongfeng , Urquhart Stephen G.
Published: June 2013

Thiophenic compounds are major constituents of fossil fuels and pose problems for fuel refinement. The quantification and speciation of these compounds is of great interest in different areas such as biology, fossil fuels studies, geology, and archaeology. Sulfur 1s Near-Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy has emerged as a qualitative and quantitative method for sulfur speciation. A firm understanding of the sulfur 1s NEXAFS spectra of organosulfur species is required for these analytical studies. To support this development, the sulfur 1s NEXAFS spectra of simple thiols and thioethers were previously examined, and are now extended to studies of thiophenic and aromatic thioether compounds, in the gas and condensed phases. High-resolution spectra have been further analyzed with the aid of Improved Virtual Orbital (IVO) and Δ(self-consistent field) ab initio calculations. Experimental sulfur 1s NEXAFS spectra show fine features predicted by calculation, and the combination of experiment and calculation has been used to improve the assignment of spectroscopic features important for the speciation and quantification of sulfur compounds. Systematic differences between gas and condensed phases are also explored; these differences suggest a significant role for conformational effects in the NEXAFS spectra of condensed species.
Raman mode random lasing in ZnS-β-carotene random gain media
Authors: Bingi Jayachandra , Warrier Anita R. , Vijayan C.
Published: June 2013

Raman mode random lasing is demonstrated in ZnS-β-carotene random gain media at room temperature. A self assembled random medium is prepared with ZnS sub micron spheres synthesized by homogeneous precipitation method. β-Carotene extracted from pale green leaves is embedded in this random medium. The emission band of ZnS random medium (on excitation at 488 nm) overlaps considerably with that of β-carotene, which functions as a gain medium. Here, random medium works as a cavity, leading to Raman mode lasing at 517 nm and 527 nm triggered by stimulated resonance Raman scattering.
A flux-coupled ac/dc magnetizing device
Authors: Gopman D. B. , Liu H. , Kent A. D.
Published: June 2013

We report on an instrument for applying ac and dc magnetic fields by capturing the flux from a rotating permanent magnet and projecting it between two adjustable pole pieces. This can be an alternative to standard electromagnets for experiments with small samples or in probe stations in which an applied magnetic field is needed locally, with advantages that include a compact form-factor, very low power requirements and dissipation as well as fast field sweep rates. This flux capture instrument (FLUXCAP) can produce fields from −400 to +400 mT, with field resolution less than 1 mT. It generates static magnetic fields as well as ramped fields, with ramping rates as high as 10 T/s. We demonstrate the use of this apparatus for studying the magnetotransport properties of spin-valve nanopillars, a nanoscale device that exhibits giant magnetoresistance.
Cooperative effect in nucleation: Nanosized seed particles jointly nucleate vapor-liquid transitions
Authors: Guo Qiumin , Liu Yawei , Jiang Guangfeng , Zhang Xianren
Published: June 2013

Using the constrained lattice density functional theory, in this work we show that when the size of critical nucleus for vapor-liquid transition is comparable to the distance between seed particles (or active sites on solid surfaces), a cooperative effect in nucleation processes is found. More specifically, neighboring seed particles are found to nucleate jointly the phase transition with a lower nucleation barrier and a different morphology of critical nucleus compared to those from an isolated seed particle. In addition, the cooperative effect, including the decrease of nucleation barrier and the morphology change of critical nucleus, is found to depend on the distance between seed particles, the fluid-solid interaction, and the particle size.
Hölder continuity of the solution map for the Novikov equation
Authors: Himonas A. Alexandrou , Holmes John
Published: June 2013

The Novikov equation (NE) has been discovered recently as a new integrable equation with cubic nonlinearities that is similar to the Camassa-Holm and Degasperis-Procesi equations, which have quadratic nonlinearities. NE is well-posed in Sobolev spaces Hs on both the line and the circle for s > 3/2, in the sense of Hadamard, and its data-to-solution map is continuous but not uniformly continuous. This work studies the continuity properties of NE further. For initial data in Hs, s > 3/2, it is shown that the solution map for NE is Hölder continuous in Hr-topology for all 0 ⩽ r < s with exponent α depending on s and r.
Comment on “Solvatochromic shifts of polar and non-polar molecules in ambient and supercritical water: A sequential quantum mechanics/molecular mechanics study including solute-solvent electron exchange-correlation” [J. Chem. Phys. 137, 214504 (2012)]
Authors: Schwabe Tobias
Published: June 2013

In this comment on a recent paper by Ma and Ma [J. Chem. Phys. 137, 214504 (2012)]10.1063/1.4769124, one of their main findings—the importance of an empirical dispersion description for the study of electronic excited states in condensed phase—is discussed. It is shown that such dispersion corrections are entirely independent of the electron coordinates and cannot improve the description of electron excitations. An alternative interpretation of the results is also given.
Response to “Comment on ‘Solvatochromic shifts of polar and non-polar molecules in ambient and supercritical water: A sequential quantum mechanics/molecular mechanics study including solute-solvent electron exchange-correlation”’ [J. Chem. Phys. 138, 217101 (2013)]
Authors: Ma Haibo , Ma Yingjin
Published: June 2013

In this response to Schwabe's recent comment [J. Chem. Phys. 138, 217101 (2013)10.1063/1.4807839], we discuss the validity of Schwabe's interpretation of why a large quantum mechanics (QM) region is needed to converge the quantum mechanics/molecular mechanics (QM/MM) results for aqueous benzene, which he ascribed to our insufficient electrostatic potential or neglect of polarization effect. It is shown that improving the electrostatic potential with ground-state polarizable effective fragment potential and fragment molecular orbital methods instead of simple point charge embedding still deviates much from the experimental determinations for aqueous benzene, and solvent polarization in response to the solute excitation for such a system is also very small. We then resuggest enlarging the QM region size or incorporating new exchange repulsion potentials in QM/MM calculations to account for exchange interaction between a solute and its nearby solvents for the highly accurate electronic spectral shift calculations of non-polar solutes dissolved in water.
Band gap widening by photonic crystal heterostructures composed of two dimensional holes and diamond structure
Authors: Chen Shibin , Li Dichen , Zhi-Hui Yuan
Published: June 2013

A new kind of heterostructures containing 3D diamond and 2D holes structures, and diamond-structure photonic crystals and 2D holes-structure photonic crystals fabricated by stereolithography and gel-casting with alumina were studied at microwave range, respectively. The heterostructures were designed by 2D holes structure embedded in 3D diamond structure, in which the lattice of three kinds of structures was equivalent. It was found that the band gaps of photonic crystal heterostructure were broadened by 124.6% and 150% comparing to that of diamond-structure crystal and 2D aerial holes structure. Experimental results showed the band gap broadened was not connected with a linear superposition of the band gap of 2D and 3D photonic crystals, which was the superposition of partial overlap.
Interface science of virtual GaN substrates on Si(111) via Sc2O3/Y2O3 buffers: Experiment and theory
Authors: Tarnawska L. , Dabrowski J. , Grzela T. , Lehmann M. , Niermann T. , Paszkiewicz R. , Storck P. , Schroeder T.
Published: June 2013

The final film quality of GaN on foreign substrates is known to crucially depend on the initial GaN interface and nucleation characteristics. To shed light on these characteristics of recently pioneered virtual, hexagonal GaN(0001) substrates on Si(111) via step graded Sc2O3(111)/Y2O3(111) buffers, a complex GaN(0001)/Sc2O3(111) interface structure model and the initial nucleation scenario is derived from a combined experimental (reflection high energy electron diffraction and X-ray photoelectron spectroscopy) and theoretical ab initio study. It is shown that the GaN/Sc2O3 interface chemistry is determined by a N-Ga-O-Sc atomic arrangement leading to N-polar GaN films. However, the atomic GaN(0001)/Sc2O3(111) interface configuration is complex and local perturbations might be at the origin of Ga-polar inversion domains in the mainly N-polar GaN films. The initial growth of GaN on Sc2O3 is characterized by an ultrathin N-Ga-O-Sc wetting layer which carries tensile strain and relaxes with increasing thickness. Further GaN deposition results in the formation of 3D islands which fully relax before island coalescence occurs. The implications of the GaN/Sc2O3 interface configuration, the 3D nucleation growth mode, and the coalescence process of misaligned islands are discussed with respect to the defect characteristics (inversion domains, cubic inclusions, threading dislocations) of the final GaN layer.
Viscoelastic deformation of a dielectric elastomer membrane subject to electromechanical loads
Authors: Wang Huiming , Lei Ming , Cai Shengqiang
Published: June 2013

Inhomogenous viscoelastic deformation is analyzed for a membrane of dielectric elastomer mounting on a rigid circular ring and subject to a combination of pressure and voltage. The membrane is assumed to be capable of large deformation, and the viscoelasticity of the membrane is represented by a nonlinear spring-dashpot model. It is found that when the applied pressure and voltage are small, the dielectric membrane gradually evolves to an equilibrium state. While if the applied pressure and voltage are large, the membrane cannot reach equilibrium state and electromechanical instability may happen with the time. The evolution of different fields in the dielectric elastomer membrane and its profile are calculated in this article. The model can be potentially used to explore time dependent behaviors of dielectric elastomeric devices.
Competition between (001) and (111) MgO thin film growth on Al-doped ZnO by oxygen plasma assisted pulsed laser deposition
Authors: Xiao Bo , Yang Qiguang , Walker Brandon , Gonder Casey A. , Romain Gari C. , Mundle Rajeh , Bahoura Messaoud , Pradhan A. K.
Published: June 2013

We report on the study of epitaxial MgO thin films on (0001) Al-doped ZnO (Al: ZnO) underlayers, grown by oxygen plasma assisted pulsed laser deposition technique. A systematic investigation of the MgO thin films was performed by X-ray diffraction and atomic force microscopy, along with the current-voltage characteristics. A distinguished behavior was observed that the preferred MgO orientation changes from (111) to (001) in the films as the growth temperature increases. Two completely different in-plane epitaxial relationships were also determined from X-ray diffraction as: [110]MgO//[112¯0]Al: ZnO and [110]MgO//[11¯00]Al: ZnO for (001) MgO with 60° rotated triplet domains, and [110]MgO//[112¯0]Al: ZnO for (111) MgO with 180° rotated twin. The pronounced temperature dependence indicates a reconciliation of the nucleation driving forces among surface, interfacial, and strain energy for heteroepitaxy of cubic MgO on hexagonal Al: ZnO. The related interfacial atomic registry is considered to be important to the formation of unusual (001) MgO on hexagonal crystals. In addition, the electrical characterization revealed a dramatic reduction of the leakage current in (001) MgO thin films, whereas the small grain size of (111) MgO is identified by atomic force microscopy as a main cause of large leakage current.
A microfluidic chip for direct and rapid trapping of white blood cells from whole blood
Authors: Chen Jingdong , Chen Di , Yuan Tao , Xie Yao , Chen Xiang
Published: June 2013

Blood analysis plays a major role in medical and science applications and white blood cells (WBCs) are an important target of analysis. We proposed an integrated microfluidic chip for direct and rapid trapping WBCs from whole blood. The microfluidic chip consists of two basic functional units: a winding channel to mix and arrays of two-layer trapping structures to trap WBCs. Red blood cells (RBCs) were eliminated through moving the winding channel and then WBCs were trapped by the arrays of trapping structures. We fabricated the PDMS (polydimethylsiloxane) chip using soft lithography and determined the critical flow velocities of tartrazine and brilliant blue water mixing and whole blood and red blood cell lysis buffer mixing in the winding channel. They are 0.25 μl/min and 0.05 μl/min, respectively. The critical flow velocity of the whole blood and red blood cell lysis buffer is lower due to larger volume of the RBCs and higher kinematic viscosity of the whole blood. The time taken for complete lysis of whole blood was about 85 s under the flow velocity 0.05 μl/min. The RBCs were lysed completely by mixing and the WBCs were trapped by the trapping structures. The chip trapped about 2.0 × 103 from 3.3 × 103 WBCs.
The impact of film thickness and substrate surface roughness on the thermal resistance of aluminum nitride nucleation layers
Authors: Su Zonghui , Freedman Justin P. , Leach Jacob H. , Preble Edward A. , Davis Robert F. , Malen Jonathan A.
Published: June 2013

Thickness dependent thermal conductivity measurements were made on aluminum nitride (AlN) thin films grown by two methods on the (0001) surfaces of silicon carbide (SiC) and sapphire substrates with differing surface roughness. We find that the AlN itself makes a small contribution to the overall thermal resistance. Instead, the thermal boundary resistance (TBR) of 5.1 ± 2.8 m2K/GW between the AlN and substrate is equivalent to 240 nm of highly dislocated AlN or 1450 nm of single crystal AlN. An order-of-magnitude larger TBR was measured between AlN films and SiC substrates with increased surface roughness (1.2 nm vs. 0.2 nm RMS). Atomic resolution TEM images reveal near-interface planar defects in the AlN films grown on the rough SiC that we hypothesize are the source of increased TBR.
Studying the short channel effect in the scaling of the AlGaN/GaN nanowire transistors
Authors: Chen Chin-Yi , Wu Yuh-Renn
Published: June 2013

This study analyzes the scalability of nitride-based nanowire high electron mobility transistors. A fully self-consistent 3D model that solves drift-diffusion and Poisson equations is employed to investigate the short-channel effect (SCE). The scaling ability of nanowire transistors with a gate-length (Lg) of 100 nm to 20 nm is examined. The current-voltage curve, current gain, subthreshold swing, and drain-induced barrier lowering results are presented. The results show that the restrained SCE is provided by the excellent gate control of the nanowire transistor. Various wire widths and gate insulators are tested to minimize the SCE for the device with a 20 nm Lg.
Magneto-optical Kerr effect spectroscopy based study of Landé g-factor for holes in GaAs/AlGaAs single quantum wells under low magnetic fields
Authors: Arora Ashish , Mandal Arjun , Chakrabarti Subhananda , Ghosh Sandip
Published: June 2013

Results from a magneto-optical Kerr effect (MOKE) spectroscopy study of ground state heavy-hole and light-hole excitons in GaAs/Al0.3Ga0.7As single quantum wells, with widths ranging from 4.3 nm to 14 nm, are presented. A novel setup and signal analysis procedure was adopted whereby polar MOKE measurements in magnetic fields up to 1.8 T could be performed with a conventional H-frame electromagnet. A first principles simulation based procedure used for simultaneously analyzing both the measured Kerr rotation and Kerr ellipticity spectral lineshapes is described in detail. The Zeeman splitting obtained from the above analysis helped to determine the longitudinal Landé g-factors. The hole g-factors were found to vary with well width, ranging from −0.6 to 1.1 for heavy-holes and 6.5 to 8.6 for light-holes. While the heavy-hole g-factor values are in fair agreement with values expected from k·p perturbation theory, no evidence is found to support theoretical predictions of possible well width dependent giant light-hole g-factors in GaAs/AlxGa1–xAs single quantum wells.
Room temperature multiferroicity in Ga0.6Fe1.4O3:Mg thin films
Authors: Thomasson A. , Cherifi S. , Lefevre C. , Roulland F. , Gautier B. , Albertini D. , Meny C. , Viart N.
Published: June 2013

We report on the multiferroic behavior of 2%-magnesium-doped Ga0.6Fe1.4O3 thin film at room temperature. The sample was grown by pulsed laser deposition on a Pt-coated Yttrium-Stabilized Zirconia substrate. Magnetic measurements indicate a net magnetization of 105 emu/cm3 at 295 K, and the persistence of magnetic ordering above room temperature. Ferroelectric measurements show clear polarization switching with negligible contribution from leakage currents, with a polarization of 0.2 μC/cm−2 and a coercive field of 133 kV/cm. Scanning probe microscopy confirms the low leakage current and detects a stable piezoelectric signal. This could open original perspectives for the application of single-phased multiferroic systems.
Fe-substituted indium thiospinels: New intermediate band semiconductors with better absorption of solar energy
Authors: Chen Ping , Chen Haijie , Qin Mingsheng , Yang Chongyin , Zhao Wei , Liu Yufeng , Zhang Wenqing , Huang Fuqiang
Published: June 2013

The indium thiospinels In2S3 and MgIn2S4 are promising host for the intermediated band (IB) photovoltaic materials due to their ideal band gap value. Here, the optical properties and electronic structure of Fe-doped In2S3 and MgIn2S4 have been investigated. All the Fe-substituted semiconductors exhibit two additional absorption bands at about 0.7 and 1.25 eV, respectively. The results of first-principles calculations revealed that the Fe substituted at the octahedral In site would introduce a partially filled IB into the band gap. Thanks to the formation of IB, the Fe-substituted semiconductors have the ability to absorb the photons with energies below the band gap. With the wide-spectrum absorption of solar energy, these materials possess potential applications in photovoltaic domain.
Charge transport and photoresponses in a single-stranded DNA/single-walled carbon nanotube composite film
Authors: Hong Wonseon , Lee Eunmo , Kue Park Jun , Eui Lee Cheol
Published: June 2013

Electrical conductivity and photoresponse measurements have been carried out on a single-stranded DNA (ssDNA)/single-walled carbon nanotube (SWNT) composite film in comparison to those of a SWNT film. While the temperature-dependent electrical conductivity of the pristine SWNT film was described well by the combined mechanism of a three-dimensional variable-range hopping and hopping conduction, that of the ssDNA/SWNT composite film followed a fluctuation-induced tunneling model. Besides, competition of photoexcited charge carrier generation and oxygen adsorption/photodesorption in the photoresponses of the films was observed and discussed in view of the role of the DNA wrapping. Thus, the biopolymer coating of the SWNTs is shown to play a significant role in modifying the charge dynamics of the composite system.
The effect of shape anisotropy on the spectroscopic characterization of the magneto-optical activity of nanostructures
Authors: Du G. X. , Saito S. , Takahashi M.
Published: June 2013

How to measure magnetic field induced magneto-optical (MO) activity of nonmagnetic elliptical plasmonic nanodisks which rest on a dielectric substrate remains a challenge since the substrate contribute most of the overall MO which varies with light polarization with respect to the orientation of the nanodisks. Here, we present a spectroscopic characterization. We find that only when light is incident from the nanostructures' side with polarization aligned with one of the two symmetry axes, one can subtract the MO contribution from the substrate by an amount equal to that of a bare one. By a detailed polarizing transmittance measurement, we determine the orientation of the two symmetry axes of the nanodisks. Light polarization is then aligned along the axes, enabling measurement of the intrinsic MO activity of gold nanodisks, which is the overall MO activity subtracted by that of a bare glass substrate. The narrow line widths of the plasmonic resonance features in the MO spectra imply a potential application in refractive index sensing.
Voltage tuning of plasmonic absorbers by indium tin oxide
Authors: Yi Fei , Shim Euijae , Zhu Alexander Y. , Zhu Hai , Reed Jason C , Cubukcu Ertugrul
Published: June 2013

We experimentally demonstrate electrical tuning of plasmonic mid-infrared absorber resonances at 4 μm wavelength. The perfect infrared absorption is realized by an array of gold nanostrip antennas separated from a back reflector by a thin dielectric layer. An indium tin oxide active layer strongly coupled to the optical near field of the plasmonic absorber allows for spectral tunability.
Magnetic anisotropy of ultrathin Fe films grown on vicinal Si (111)
Authors: Liu Hao-Liang , He Wei , Wu Qiong , Ye Jun , Zhang Xiang-Qun , Yang Hai-Tao , Cheng Zhao-Hua
Published: June 2013

We have investigated magnetic anisotropy of ultrathin Fe films grown on vicinal Si (111) with 4° miscut towards [11-2] direction. Spin reorientation transition (SRT) from out-of-plane to in-plane proceeds in a wider thickness range than on flat substrates. Meanwhile, the easy axis of in-plane uniaxial magnetic anisotropy varies from [11-2] to [-110] with an intermediate state of approximate four-fold symmetry. The evolution of magnetic anisotropy is attributed to competition of surface magnetic anisotropy, first-order magnetocrystalline anisotropy, and step induced magnetic anisotropy from symmetry breaking and dipolar interactions.
Degeneration of the Julia set to singular loci of algebraic curves
Authors: Saito Satoru , Saitoh Noriko , Harada Hiromitsu , Yumibayashi Tsukasa , Wakimoto Yuki
Published: June 2013

We show that, when a non-integrable rational map changes to an integrable one continuously, a large part of the Julia set of the map approach indeterminate points (IDP) of the map along algebraic curves. We will see that the IDPs are singular loci of the curves.
Improvement of salt and waterlogging tolerance in wheat: comparative physiology of Hordeum marinum-Triticum aestivum amphiploids with their H. marinum and wheat parents
Authors: Alamri Saud A. , Barrett-Lennard Edward G. , Teakle Natasha L. , Colmer Timothy D.
Published: June 2013

Hordeum marinum Huds. is a waterlogging-tolerant halophyte that has been hybridised with bread wheat (Triticum aestivum L.) to produce an amphiploid containing both genomes. This study tested the hypothesis that traits associated with waterlogging and salinity tolerances would be expressed in H. marinum-wheat amphiploids. Four H. marinum accessions were used as parents to produce amphiploids with Chinese Spring wheat, and their responses to hypoxic and 200 mM NaCl were evaluated. Relative growth rate (RGR) in the hypoxic-saline treatment was better maintained in the amphiploids (58–71% of controls) than in wheat (56% of control), but the amphiploids were more affected than H. marinum (68–97% of controls). In hypoxic-saline conditions, leaf Na+ concentrations in the amphiploids were lower than in wheat (30–41% lower) but were 39–47% higher than in the H. marinum parents. A strong barrier to radial oxygen loss formed in basal root zones under hypoxic conditions in two H. marinum accessions; this barrier was moderate in the amphiploids, absent in wheat, and was weaker for the hypoxic-saline treatment. Porosity of adventitious roots increased with the hypoxic treatments; values were 24–38% in H. marinum, 16–27% in the amphiploids and 16% in wheat. Overall, the amphiploids showed greater salt and waterlogging tolerances than wheat, demonstrating the expression of relevant traits from H. marinum in the amphiploids.
Polarized Deep Inelastic Scattering
Authors: Steffens F. M. , Thomas A. W.
Published: June 2013

We give an overview of present calculations involving the proton spin
structure function. It is shown that a significant part of the discepancy
between the data and the Ellis–Jaffe sum-rule may arise through the
axial anomaly if the gluons within the proton are strongly polarized. While a
quark model, such as the MIT bag, does not include the anomaly, and therefore
cannot be expected to reproduce the spin structure function, it does give a
rather good description of recent data which is anomaly free, such as the
distribution of polarized, valence up-quarks in the proton.
Monopole Dominance for Nonperturbative QCD
Authors: Suganuma H. , Umisedo S. , Sasaki S. , Toki H. , Miyamura O.
Published: June 2013

Monopole dominance for the nonperturbative features in QCD is studied both in
the continuum and the lattice gauge theories. First, we study the dynamical
chiral-symmetry breaking (DχSB) in the dual Higgs theory using the
effective potential formalism. We find that the main driving force for
DχSB is brought from the confinement part in the nonperturbative gluon
propagator rather than the short-range part, which means monopole dominance
for DχSB. Second, the correlation between instantons and
QCD–monopoles is studied. In the Polyakov-like gauge, where
A4(x) is
diagonalized, the QCD–monopole trajectory penetrates the centre of each
instanton, and becomes complicated in the multi-instanton system. Finally,
using the SU(2) lattice gauge theory with 164 and
163 × 4, the instanton number is measured in the
singular (monopole-dominating) and regular (photon-dominating) sectors,
respectively. Instantons and anti-instantons only exist in the monopole sector
both in the maximally abelian gauge and in the Polyakov gauge, which means
monopole dominance for the topological charge.
h-Meson Decays and Strong UA(1) Breaking in the Three-flavour Nambu - Jona-Lasinio Model
Authors: Takizawa M. , Nemoto Y. , Oka M.
Published: June 2013

We study the η → γγ and η → π
0γγ decays using an extended three-flavour
Nambu–Jona-Lasinio model that includes the ’t Hooft instanton
induced interaction. We find that the η-meson mass, the η →
γγ decay width and the η → π
0γγ decay width are in good agreement with the
experimental values when the UA(1)
breaking is strong and the flavour SU(3) singlet-octet
mixing angle θ is about zero. The effects of the
UA(1) breaking on the baryon
number one and two systems are also studied.
Kaon Condensation and Dilepton Production from Strange Hadronic Matter
Authors: Tatsumi T. , Shin H. , Maruyama T. , Fujii H.
Published: June 2013

We consider modification of kaons and the implications for dilepton production
in the early stage of high-energy heavy-ion collisions. Constructing the
equation of state of hadronic matter, including kaons as well as hyperons
Λ with recourse to the relativistic mean-field theory, we study the
production rate of dileptons. The possibility of
K+ condensation is also revisited
in this framework.
Chiral Symmetry Breaking in the Dual Ginzburg - Landau Theory
Authors: Toki Hiroshi , Sasaki Shoichi , Ichie Hiroko , Suganuma Hideo
Published: June 2013

Confinement and spontaneous chiral symmetry breaking are the most fundamental
phenomena in quark nuclear physics, where hadrons and nuclei are described in
terms of quarks and gluons. The dual Ginzburg–Landau (DGL) theory
contains monopole fields as the most essential degrees of freedom. Their
condensation in the vacuum is modelled to describe quark confinement in strong
connection with QCD. We then demonstrate that the DGL theory is able to
describe the spontaneous breakdown of chiral symmetry.
Fabrication of YBa2Cu3Oy Thin Films on Textured Buffer Layers grown by Plasma Beam Assisted Deposition
Authors: Fukutomi M. , Kumagai S. , Maeda H.
Published: June 2013

A new technique named plasma beam assisted deposition (PBAD) is proposed to
grow in-plane textured yttria-stabilised zirconia (YSZ) thin films on
polycrystalline metallic substrates as a buffer layer for deposition of
YBa2Cu3Oy
(YBCO) films. The in-plane texturing of the YBCO films obtained is decisively
governed by that of the YSZ buffer layer on which the YBCO grows. Because of a
reduction of the weak links at high-angle grain boundaries, a marked increase
in the critical current density Jc
is observed with improved texturing of the YBCO films. So far, it has been
demonstrated that YBCO films with
Jc above 105
A cm-2 (77 K, 0 T) can be successfully deposited by a
laser ablation technique. The PBAD process proposed here is found to be
valuable technologically because it offers a very convenient method to grow
textured films on long tape or large area substrates. An attempt was also made
to grow textured films simultaneously on one side or both sides of various
pieces of tape substrates. The results indicate that PBAD is one potential
technique for future large scale application of YBCO films.
Application of High Temperature Superconductors in Passive Microwave Devices
Authors: Dew-Hughes David
Published: June 2013

The front end of a microwave communications system is assembled from circuit
elements comprising antennae, local oscillator, mixer and filters.
Interconnection is by transmission line, into which delay may be incorporated.
All of these components can, with advantage, be implemented in superconducting
material. Superconductors, when operating below their cross-over frequency,
have values of surface resistance lower than those for normal metals such as
copper and silver. This results in lower insertion loss for microwave
components, allowing the design of smaller, more compact, yet at the same time
more complicated, devices. The non-dispersive nature of superconductors can
also be an advantage in enabling very high bandwidth signal processing. High
temperature superconductors (HTS) allow operating temperatures in the liquid
nitrogen range, not too far below the ambient temperature in many
communications satellites. The Oxford microwave programme has concentrated on
the implementation of all of the above devices in thin-film HTS, mainly
Tl-2212, on a variety of substrates. The film fabrication, and performance of
delay lines, antenna-mixers, resonators, filters and a voltage-controlled
oscillator, are described.
Diffusion Cooling of Electrons in an A.C. Field
Authors: Robson R. E.
Published: June 2013

Boundaries affect the measured values of transport coeffcients in all drift
tube experiments, to a greater or lesser extent, and nowhere is this more
apparent than in the experiment first devised by Cavalleri (1969) and
subsequently adapted by Crompton and coworkers in the 1970s. The phenomenon of
‘diffusion cooling’ is particularly striking and arises
essentially from a penetration of the ‘boundary layer’ (of
thickness of the order of the mean free path for energy exchange) throughout a
significant portion of the gas chamber. Although this is something of an
obstacle to extracting the classical diffusion coefficient from experimental
data, it is of great interest in its own right from a theoretical point of
view, and the Crompton et al. experiments motivated
several theoretical treatments which successfully explained diffusion cooling,
albeit for zero applied field and on the basis of the ‘two-term’
spherical harmonic representation of the velocity distribution function. The
present paper puts these theories in the context of the modern, generalised
eigenvalue theory, which may be used as a basis for describing all swarm
experiments. In addition, the earlier zero-field studies are generalised to
the extent that an a.c. heating field is included, as was the case for the
original Cavalleri experimental set-up. This field is found to enhance
diffusion cooling effects for a simple model cross section.
Wigner’s Variant of Bell’s Inequality
Authors: Geurdes Johannes F.
Published: June 2013

It is shown that Wigner’s variant of Bell’s inequality does not
exclude all local hidden variable explanations of the
Einstein–Podolsky–Rosen problem.
Electron Dichroism: Interaction of Spin-polarised Electrons with Chiral Molecules
Authors: Kessler Joachim
Published: June 2013

This paper discusses a problem which would be worth studying with (e, 2e)
experiments, a technique which has been so successfully used by Erich Weigold:
Can spin-polarised electrons distinguish between left- and right-handed
molecules? This has been a matter of long-standing discussion and speculation
and of controversial experiments. The results presented here show that the
attenuation of electron beams passing through chiral molecules is clearly
spin-dependent. This is analogous to the circular dichroism of light and is
therefore called electron dichroism. The size of the effect agrees with what
has been predicted by theoretical estimates.
Dependence of Faraday Effects on Radio Luminosity and Redshift
Authors: Ubachukwu A. A. , Ugwoke A. C. , Chukwude A. E.
Published: June 2013

Quantitative estimates are provided for the influence of luminosity selection
effects present in a bright source sample on the observed correlation of the
depolarisation rate Λ ½ with redshift
z . It is shown that the observed correlation is partly
intrinsic and partly due to luminosity effects. More specifically, we find
that ~46% of the observed Λ ½
correlation with z can be attributed to strong
luminosity selection effects in the sample. This shows that a significant
fraction (~54%) of the observed correlation is cosmological in
origin. It is concluded that there is a cosmological evolution of
Λ ½, over and above that resulting from
luminosity selection effects, which may be related to the epoch dependent
properties of the ambient medium through which the radio source components
propagate.
Effect of the Motion of Ions on the Penetration of a Rotating Magnetic Field into a Plasma Cylinder
Authors: Hugrass W. N.
Published: June 2013

A simplified model for the rotating magnetic field (RMF) current drive in an
infinitely long cylindrical plasma is considered. The model allows for motion
of both the electron and ion fluids in the z and θ
directions. It is assumed that equilibrium is satisfied on the average and
hence the r components of the equations of motion are
not considered. It is shown that the motion of the ion fluid does not
introduce any significant modifications to the nonlinear mechanism for the
penetration of the RMF into the plasma.
Small Polaron Hopping Conduction in Samples of Ceramic La1 · 4Sr1 · 6Mn2O7 · 06
Authors: Nakatsugawa H. , Iguchi E. , Jung W. H. , Munakata F.
Published: June 2013

The ceramic sample of La1 ·
4Sr1 ·
6Mn2O7
· 06 exhibits the metal-insulator transition and
a negative magnetoresistance in the vicinity of the Curie temperature
(T ⋍ 100 K). The dc magnetic susceptibility
between 100 K and 280 K is nearly constant and decreases gradually with
increasing temperature above 280 K. The measurements of dc resistivity and the
thermoelectric power indicate that small polaron hopping conduction takes
place at T > 280 K. The spin ordering due to the two-dimensional d x 2
¡ y 2 state occurring at T > 280 K is directly related to the hopping
conduction above 280 K, although the spin ordering due to the one-dimensional
d 3z 2 ¡ r 2 state takes place at T > TC. The two-dimensional d x 2
¡ y 2 state extending within the MnO2 sheets starts to narrow and leads
to the carrier localisation at 280 K. The effective number of holes in this
sample estimated from the thermoelectric power is considerably smaller than
the nominal value. This indicates that the small polaron hopping conduction
takes place predominantly within the in-plane MnO2
sheets. A discussion is given of the experimental results of the ceramic
sample of
La2/3Ca1/3MnO2·98.
Radial Structure of Electron Drift Waves in Tokamak Geometry
Authors: Lewandowski J. L. V.
Published: June 2013

The radial structure of electron drift waves in a low-pressure tokamak plasma
is presented. The ions are cold and an electrostatic approximation for the
fluctuating potential is used. It is shown that problem of the radial
structure of drift waves in toroidal geometry is amenable to a two-step
solution; in the first approximation, the radial structure of the mode is
neglected and the problem to be solved is the usual eigenmode equation along
the (extended) poloidal angle; in the second approximation, the mode amplitude
is expanded in ascending powers of the parameter
(k⊥Ln)–1/2,
where k⊥ is the magnitude of
the lowest-order wavevector and Ln
is the radial density scalelength. The implications of these radially-extended
drift-type modes for the anomalous cross-field diffusion are discussed.
(d,p) Reactions to the Ground States of 41Ca and 49Ca
Authors: King K , McKellar BHJ
Published: June 2013

Calculations for (d, p) stripping on the doubly magic calcium nuclei 40Ca and 48Ca leading to the ground states of 41Ca and 49Ca have been carried out on the basis of the sudden approximation method of deuteron stripping developed by Butler, Hewitt, McKellar, and May.
The Momentum Transfer Cross Section for Electrons in Helium Derived from Drift Velocities at 77°K
Authors: Crompton RW , Elford MT , Robertson AG
Published: June 2013

Drift velocities of electrons in helium at 76.8�K have been measured for 8 X lO−20 ≤ E/N ≤ 2 X lO−17 V cm2. From these data, and the earlier measurements of Crompton, Elford, and Jory made at 293�K, the energy-dependent momentum transfer cross section has been determined for electrons with energies between 0.008 and 6 eV. The present cross section agrees with that of Crompton, Elford, and Jory to within 1 %. The extension of the energy range to 8 meV permits a direct determination of the scattering length, for which a value of 1.19 ao is obtained.
The Cross Sections for Rotational Excitation of H2 And D2 by Low Energy Electrons
Authors: Gibson DK
Published: June 2013

The J = 1 --+ 3 rotational cross section for H2 has been derived from an analysis of electron transport coefficients; A new technique is described for calculating the energy distribution functions taking into account superelastic collisions, since these must be included for an analysis of low energy transport data in D2. Unique rotational cross sections cannot be obtained for this gas from the experimental data available, but two sets of cross sections have been derived which are compatible with the existing data and are also in accord with recent theoretical calculations
pd Topological Cross Sections in the Momentum Range 50?920 MeV/c
Authors: Burrows RD , Caro DE , Gold E , Klein AG , MacDowell CE , Olney JL , Opat GI , Starr J , Wignall JWG , Peaslee DC
Published: June 2013

The total and topological cross sections are presented for events seen in the interaction of 50-920 MeVle antiprotons with deuterium in the BNL 30 in. bubble chamber.
On the Theory of Type II and Type III Solar Radio Bursts. I. The Impossibility of Nonthermal Emission due to Combination Scattering Off Thermal Fluctuations
Authors: Melrose DB
Published: June 2013

Combination scattering as proposed by Ginzburg and Zhelezniakov involves the coalescence of electron plasma waves from a nonthermal distribution with electron plasma waves from the distribution of thermal charge fluctuations. Reabsorption is neglected.
A Fast Correlation Method for Studying Drifting Patterns Associated with Ionospheric Irregularities
Authors: Clark DH , Stevenson DJ
Published: June 2013

The method commonly used in the analysis of drifting patterns associated with ionospheric irregularities is the full-correlation method of Briggs, Phillips, and Shinn (1950, hereafter referred to as BPS). A full-correlation analysis requires lengthy calculations, even on a digital computer, as it involves repetitive calculations and complicated curve-fitting techniques.
An Experimental Test of the Streamer Breakdown Criterion
Authors: Cavenor MC
Published: June 2013

The filamentary spark channel, resulting from the electrical breakdown of a gas, generally forms in one of two ways. At voltages close to the minimum breakdown potential the spark channel has been shown to develop from the constriction of the diffuse glow discharge formed from the superposition of many generations of electron avalanches (Cavenor and Meyer 1969).
Sub-Coulomb Stripping in the 124Sn(d,p)125Sn Reaction
Authors: Powell DL , Dallimore PJ , Davidson WF
Published: June 2013

Angular distributions for the reaction 124Sn(d, p)125Sn leading to the unresolved ground and O� 026 MeV levels and to the 0'210, O� 936, 1 -257, 1� 362, and 1 . 540 MeV levels of 125Sn have been measured with deuteron energies of 5� 1 and 12-0MeV. Spectroscopic factors have been extracted using the DWBA theory. The dependence of the calculations on various assumptions of the theory has been studied by comparing the results at both energies. The sub-Coulomb data have been found to yield more reliable spectroscopic factors because of the lack of sensitivity to the optical model parameters used in the distorting potentials.
Prompt Neutrons From 236U Fission Fragments
Authors: Boldeman JW , de L Musgrove AR , Walsh RL
Published: June 2013

Measurements have been made of prompt neutron emission in the thermal neutron fission of 235 U and the mean neutron emission per fragment has been obtained for particular values of the fragment mass and total kinetic energy. A direct neutron counting method was employed and a comparison is made with data from previous experiments of this type.
Conjugate Conductivity Asymmetry and the Precipitation of Magnetospheric Electrons
Authors: Catchpoole JR
Published: June 2013

Using a simplified model of the atmosphere, a calculation is made of the windinduced vertical redistribution of ions derived from the 100 km level. Assuming the effect to be dissimilar in magnitude at the conjugate point, a potential difference will be set up in this way between the ends of the magnetic field line. For various values of the parameters involved, an estimate is made of the consequent precipitation to ionospheric heights of previously trapped electrons of the magnetosphere.
The Polarization of Extended Radio Sources at 6 cm Wavelength. II. Galactic Sources
Authors: Whiteoak JB , Gardner FF
Published: June 2013

Maps are presented of the polarization and total intensity distributions over the supernova remnants 13S6A, MSH 15-56, ROW 103, and W44. They were obtained at 6 cm wavelength with a 4' arc resolution. It has not proved possible to interpret the polarization characteristics in terms of a simple expansion against the interstellar magneto ionic medium.
An Approximation to the Reaction Matrix in Nuclear Matter
Authors: Blatt DWE , McKellar BHJ
Published: June 2013

It has been shown by Butler et al. that a good approximation to the Bethe-Goldstone wavefunction can be constructed from eigenfunctions of the free two-nucleon system. The approximation is therefore closely related to the T-matrix. In this paper, it is used to derive an approximate G-matrix in terms of the T-matrix. As an illustration of this approach, the resulting approximate G-matrix is compared with the reference spectrum approximation of Bethe, Brandow, and Petschek for the simple case of a pure hard core potential.
The Friction Coefficient Formalism in the Statistical Mechanics of Transport Processes
Authors: Fisher RA , Watts RO
Published: June 2013

Kirkwood's theory for the friction coefficient in Brownian motion relates the transport coefficients to the microscopic properties of a system through the time integral of a force autocorrelation function. The expression is useful subject to the validity of certain assumptions on the form of the autocorrelation function. These restrictions and the predicted diffusion coefficients have been examined using the method of molecular dynamics. It is shown that the assumptions are invalid and that when Kirkwood's expression is evaluated exactly it gives negative self-diffusion coefficients. This leads to the conclusion that the friction coefficient approach to transport in simple systems is physically unreasonable and should no longer be used.
Exact Energy of Interaction Between Nonpolar Molecules Represented as Dipoles
Authors: Mitchell DJ , Ninham BW , Richmond P
Published: June 2013

A new non-perturbative method is developed for deriving the energy of interaction between molecules represented as polarizable dipoles. The method is applied to obtain the exact energy of interaction for two anisotropic electric dipoles and for three dipoles in the isotropic case. The results of London and of Casimir and Polder are special limiting cases. Deviations of the London energy from the exact result are investigated. A new feature which emerges is that the potential energy becomes repulsive at very small distances of separation.
Cosmological Models with Two Fluids. I. Robertson?Walker Metric
Authors: McIntosh CBG
Published: June 2013

Exact solutions in terms of elementary functions are given for flat, homogeneous and isotropic, relativistic cosmological models which contain two fluids, each with an equation of state of the form where p is the pressure, ? is the density, is a constant, and For other forms of v1/v2, the relevant solution is given in terms of a hypergeometric function. The cases when one of the v?s is equal to 2/3 or 2 are analogous to models with a Robertson?Walker metric with k = � 1 and to anisotropic models of the type discussed by Jacobs respectively. All solutions for the two-fluid models can be written in terms of elementary functions when v1 = 0, which is analogous to a cosmological constant. The fact that all two-fluid solutions with v1 = 2/3 which can be written in terms of elementary functions are given means that all such one-fluid solutions with k = � 1 are given.
Cosmological Models with Two Fluids. II. Conformal and Conformally Flat Metrics
Authors: McIntosh CBG , Foyster JM
Published: June 2013

Similar solutions to those in Part I are given for two-fluid cosmological models when the Robertson?Walker metric in its usual form is replaced by "conformal" and "conformally flat" forms. In these cases the solutions can be written in terms of elementary functions when (3v1?2)/(3v2?2) = 1?m?1, m = 1,2,3,... The relation of these solutions to one-fluid solutions with k = � 1 is also discussed.
Observations at 2700 MHz of Selected Planetary Nebulae
Authors: Aller LH , Milne DK
Published: June 2013

Observations at 2700 MHz of 74 planetary nebulae have been obtained with the Parkes 64 m radio telescope. Comparison is made with the optically determined H� intensity to obtain extinction coefficients in these directions.
Solutions of the Relativistic Two-Body Problem. II. Quantum Mechanics
Authors: Cook JL
Published: June 2013

This paper discusses the formulation of a quantum mechanical equivalent of the relative time classical theory proposed in Part I. The relativistic wavefunction is derived and a covariant addition theorem is put forward which allows a covariant scattering theory to be established. The free particle eigenfunctions that are given are found not to be plane waves. A covariant partial wave analysis is also given. A means is described of converting wavefunctions that yield probability densities in 4-space to ones that yield the 3-space equivalents. Bound states are considered and covariant analogues of the Coulomb potential, harmonic oscillator potential, inverse cube law of force, square well potential, and two-body fermion interactions are discussed.
Coulomb Interference in the Half-Shell T-Matrix Derived from the Hamada?Johnston Potential
Authors: McCarthy IE , Tandy PC
Published: June 2013

The calculation of the half-shell two-nucleon t-matrix from the wavefunction duo to the Hamada?Johnston potential in the presence of the Coulomb interaction is described. The contribution from the long range nature of the Coulomb interaction is included and its effect on the half-shell t-matrix is indicated.