bluuebunny/crossref_metadata_2025 huggingface dataset:
Fabrication and thermal stability characterisation of Ru electrode used for high power contact radio frequency microelectromechanical system switch
Authors: Zhang Hongze , Wang Wei , Li Zhihong
Published: September 2013

Reported are the fabrication and thermal stability of an Ru electrode, which is used for a high power Ru–Au contact radio frequency microelectromechanical system switch with a microspring contact design. In this reported work, a new process with bilayer lift‐off and a strain release layer is developed, thereby acquiring the 3000 Å Ti/Au/Ru electrode with excellent smooth edges for high‐power handling capacity and low loss. Furthermore, thermal tests under 400, 500 and 600°C for over 1 h have been performed. Investigation of the surface with scanning electron microscopy and energy dispersive X‐ray spectroscopy shows that the electrode has a good thermal stability at 400°C, which is proper for high‐power handling. The cold switch DC current handling capacity is advanced from <90 mA per point (failed) to 100 mA per point (still working).
Conversion of CH4/CO2 to syngas over Ni-Co/Al2O3-ZrO2 nanocatalyst synthesized via plasma assisted co-impregnation method: Surface properties and catalytic performance
Authors: Rahemi Nader , Haghighi Mohammad , Akbar Babaluo Ali , Fallah Jafari Mahdi , Khorram Sirous
Published: September 2013

Ni/Al2O3 catalyst promoted by Co and ZrO2 was prepared by co-impregnation method and treated with glow discharge plasma. The catalytic activity of the synthesized nanocatalysts has been tested toward conversion of CH4/CO2 to syngas. The physicochemical characterizations like XRD, EDX, FESEM, TEM, BET, FTIR, and XPS show that plasma treatment results in smaller particle size, more surface concentration, and uniform morphology. The dispersion of nickel in plasma-treated nanocatalyst was also significantly improved, which was helpful for controlling the ensemble size of active phase atoms on the support surface. Improved physicochemical properties caused 20%–30% enhancement in activity of plasma-treated nanocatalyst that means to achieve the same H2 or CO yield, the plasma-treated nanocatalyst needed about 100 °C lower reaction temperature. The H2/CO ratio got closer to 1 at higher temperatures and finally at 850 °C H2/CO = 1 is attained for plasma-treated nanocatalyst. Plasma-treated nanocatalyst due to smaller Ni particles and strong interaction between active phase and support has lower tendency to keep carbon species on its structure and hence excellent stability can be observed for this catalyst.
Potential production and distribution of microalgae in China
Authors: Zhou Xinping , Yuan Shuo , Wu Cai , Song Bao , Peng Shanling
Published: September 2013

Microalgae are considered a promising biofuel resource to fix carbon dioxide (CO2), which can support social development and environmental improvement in the future. In this paper, characteristics of microalgae growth with two parameters of solar radiation and ambient temperature are investigated based on industrial-scale microalgae bulk growth model of Quinn et al. By using this model, the potential biomass production of microalgae in China is estimated based on data of the available untilled lands and the weather to be 7.38 × 109 tonnes. This is 2.4 times larger than China's energy consumption of 3.08 × 109 tonnes standard coal equivalent in 2010, and satisfies that predicted with an exponentially increasing trend for 2020, and 89% of the amount predicted for 2030. The annual total CO2 emissions reduced is estimated to be 13.5 × 109 tonnes, which can improve the natural environment besides supplying sustainable production in China.
Instability of wave modes in a two-stream free-electron laser with a helical wiggler and an axial magnetic field
Authors: Mohsenpour Taghi , Mehrabi Narges
Published: September 2013

The dispersion relation of a two-stream free-electron laser (TSFEL) with a one-dimensional helical wiggler and an axial magnetic field is studied. Also, all relativistic effects on the space-charge wave and radiation are considered. This dispersion relation is solved numerically to find the unstable interaction among the all wave modes. Numerical calculations show that the growth rate is considerably enhanced in comparison with single-stream FEL. The effect of the velocity difference of the two electron beams on the two-stream instability and the FEL resonance is investigated. The maximum growth rate of FEL resonance is investigated numerically as a function of the axial magnetic field.
Perturbed atoms in molecules and solids: The PATMOS model
Authors: Røeggen Inge , Gao Bin
Published: September 2013

A new computational method for electronic-structure studies of molecules and solids is presented. The key element in the new model – denoted the perturbed atoms in molecules and solids model – is the concept of a perturbed atom in a complex. The basic approximation of the new model is unrestricted Hartree Fock (UHF). The UHF orbitals are localized by the Edmiston-Ruedenberg procedure. The perturbed atoms are defined by distributing the orbitals among the nuclei in such a way that the sum of the intra-atomic UHF energies has a minimum. Energy corrections with respect to the UHF energy, are calculated within the energy incremental scheme. The most important three- and four-electron corrections are selected by introducing a modified geminal approach. Test calculations are performed on N2, Li2, and parallel arrays of hydrogen atoms. The character of the perturbed atoms is illustrated by calculations on H2, CH4, and C6H6.
A versatile elevated-pressure reactor combined with an ultrahigh vacuum surface setup for efficient testing of model and powder catalysts under clean gas-phase conditions
Authors: Morfin Franck , Piccolo Laurent
Published: September 2013

A small-volume reaction cell for catalytic or photocatalytic testing of solid materials at pressures up to 1000 Torr has been coupled to a surface-science setup used for standard sample preparation and characterization under ultrahigh vacuum (UHV). The reactor and sample holder designs allow easy sample transfer from/to the UHV chamber, and investigation of both planar and small amounts of powder catalysts under the same conditions. The sample is heated with an infrared laser beam and its temperature is measured with a compact pyrometer. Combined in a regulation loop, this system ensures fast and accurate temperature control as well as clean heating. The reaction products are automatically sampled and analyzed by mass spectrometry and/or gas chromatography (GC). Unlike previous systems, our GC apparatus does not use a recirculation loop and allows working in clean conditions at pressures as low as 1 Torr while detecting partial pressures smaller than 10−4 Torr. The efficiency and versatility of the reactor are demonstrated in the study of two catalytic systems: butadiene hydrogenation on Pd(100) and CO oxidation over an AuRh/TiO2 powder catalyst.
A new, low temperature long-pass cell for mid-infrared to terahertz spectroscopy and synchrotron radiation use
Authors: Kwabia Tchana Fridolin , Willaert Fabrice , Landsheere Xavier , Flaud Jean-Marie , Lago Leatitia , Chapuis Mylène , Herbeaux Christian , Roy Pascale , Manceron Laurent
Published: September 2013

A new cell has been designed for accurate spectroscopic measurements in the 80–400 K temperature range with variable path lengths from 3 to more than 141 m. The spectral coverage at these temperatures ranges from the visible to less than 10 cm−1, thanks to the use of diamond windows. The design of the cryostat and vacuum setups allows vibration-free operation. The equipment provides temperature homogeneity and pressure control to better than 2% over the 100–400 K and the 0.1–1000 mbar ranges. Remote-controlled opto-mechanical systems enable in situ adjustments as well as changes of the optical path length within half an hour, in order to optimize measurement time in an open user facility. It allows then to meet the specific requirements of high resolution measurements on the Far-Infrared AILES beamline at SOLEIL as well at the LISA facility, in Créteil, in the mid-IR. This new instrument opens up the way for many experiments in the field of high-resolution gas-phase IR spectroscopy, in particular, in quantitative spectroscopy for atmospheric applications: measurements of absorption line parameters (absolute intensities, cross sections, and pressure-induced widths) using Fourier transform spectroscopy. The design and performance of the equipment are briefly presented and illustrated on spectroscopic examples.
Derivation of a true (t → 0+) quantum transition-state theory. II. Recovery of the exact quantum rate in the absence of recrossing
Authors: Althorpe Stuart C. , Hele Timothy J. H.
Published: September 2013

In Paper I [T. J. H. Hele and S. C. Althorpe, J. Chem. Phys. 138, 084108 (2013)]10.1063/1.4792697 we derived a quantum transition-state theory (TST) by taking the t → 0+ limit of a new form of quantum flux-side time-correlation function containing a ring-polymer dividing surface. This t → 0+ limit appears to be unique in giving positive-definite Boltzmann statistics, and is identical to ring-polymer molecular dynamics (RPMD) TST. Here, we show that quantum TST (i.e., RPMD-TST) is exact if there is no recrossing (by the real-time quantum dynamics) of the ring-polymer dividing surface, nor of any surface orthogonal to it in the space describing fluctuations in the polymer-bead positions along the reaction coordinate. In practice, this means that RPMD-TST gives a good approximation to the exact quantum rate for direct reactions, provided the temperature is not too far below the cross-over to deep tunnelling. We derive these results by comparing the t → ∞ limit of the ring-polymer flux-side time-correlation function with that of a hybrid flux-side time-correlation function (containing a ring-polymer flux operator and a Miller-Schwarz-Tromp side function), and by representing the resulting ring-polymer momentum integrals as hypercubes. Together with Paper I, the results of this article validate a large number of RPMD calculations of reaction rates.
Theoretical investigation of the electron capture and loss processes in the collisions of He2+ + Ne
Authors: Hong Xuhai , Wang Feng , Jiao Yalong , Su Wenyong , Wang Jianguo , Gou Bingcong
Published: September 2013

Based on the time-dependent density functional theory, a method is developed to study ion-atom collision dynamics, which self-consistently couples the quantum mechanical description of electron dynamics with the classical treatment of the ion motion. Employing real-time and real-space method, the coordinate space translation technique is introduced to allow one to focus on the region of target or projectile depending on the actual concerned process. The benchmark calculations are performed for the collisions of He2+ + Ne, and the time evolution of electron density distribution is monitored, which provides interesting details of the interaction dynamics between the electrons and ion cores. The cross sections of single and many electron capture and loss have been calculated in the energy range of 1–1000 keV/amu, and the results show a good agreement with the available experiments over a wide range of impact energies.
Influence of oxygen contamination on minority carrier lifetime and defect density in nanocrystalline Si
Authors: Kajjam Shantan , Konduri Siva , Dalal Vikram L.
Published: September 2013

We report on the energetic locations of the defects created by oxygen in nanocrystalline Si and the relationship between defects and minority carrier lifetime. The energy of the defects was determined using capacitance-frequency measurements, and the minority carrier lifetime was determined using reverse recovery measurements. We show that oxygen increases deep defect densities, with the defect densities being measured between 0.35 eV and 0.55 eV below the conduction band. It is found that oxygen-induced defects can be reduced and lifetime increased by compensating with B. The minority carrier lifetime is found to be inversely proportional to defect density and the capture-cross section of holes is estimated to be ∼4 × 10−17 cm2.
Modeling of the dye loading time influence on the electrical impedance of a dye-sensitized solar cell
Authors: Pugliese D. , Shahzad N. , Sacco A. , Tresso E. , Alexe-Ionescu A. L.
Published: September 2013

A hemisquaraine dye molecule (CT1) was used as TiO2 sensitizer. The influence of the dye-adsorption time on the electrical impedance of a CT1-based dye-sensitized solar cell (DSC) was analyzed. Differently from what we observed with commercial Ru dye-based DSC, a non-monotonic effect of the impregnation time on the impedance has been found and the dye loading time is much reduced, a desirable outcome in economic grounds. This feature is analyzed in terms of the dye molecules tendency to aggregate close to the TiO2/electrolyte interface. A physical model that fits well the experimental data is proposed, which also takes into account a correction related to the difference between the illuminated area of the cell and the total area available in the electrical measurements.
Variational method applied to two-component Ginzburg-Landau theory
Authors: Romaguera Antonio R. de C. , Silva K. J. S.
Published: September 2013

In this paper, we apply a variational method to two-component superconductors, as in the MgB2 materials, using the two-component Ginzburg-Landau (GL) theory. We expand the order parameter in a series of eigenfunctions containing one or two terms in each component. We also assume azimuthal symmetry to the set of eigenfunctions used in the mathematical procedure. The extension of the GL theory to two components leads to the quantization of the magnetic flux in fractions of ϕ0. We consider two kinds of component interaction potentials: Γ1|ΨI|2|ΨII|2 and \documentclass[12pt]{minimal}\begin{document}$\Gamma _2(\Psi _I^*\Psi _{II}+\Psi _I\Psi _{II}^*)$\end{document}Γ2(ΨI*ΨII+ΨIΨII*). The simplicity of the method allows one to implement it in a broad range of physical systems, such as hybrid magnetic-superconducting mesoscopic systems, texturized thin films, metallic hydrogen superfluid, and mesoscopic superconductors near inhomogeneous magnetic fields, simply by replacing the vector potential by its corresponding expression. As an example, we apply our results to a disk of radius R and thickness t.
DNA overstretching transition induced by melting in a dynamical mesoscopic model
Authors: Pupo Ana Elisa Bergues , Falo Fernando , Fiasconaro Alessandro
Published: September 2013

We present a phenomenological dynamical model describing the force induced melting as responsible for the DNA overstretching transition. The denaturation mechanism is developed under the framework of the mesoscopic one-dimensional Peyrard-Bishop-Dauxois (PBD) picture which models the melting features of a polymer chain by means of a Morse potential and the stacking interaction. We find a good agreement with both the experimental overstretching curve and the asymmetric hysteretic properties with different simulation times. The comparison of the standard PBD model with a modification of the Morse potential which takes into account the interaction with the solvent has been also successfully investigated.
Aeroacoustics and aerodynamics of impinging supersonic jets: Analysis of the screech tones
Authors: Sinibaldi G. , Lacagnina G. , Marino L. , Romano G. P.
Published: September 2013

The interaction between acoustics and aerodynamics of a supersonic jet is an actual fundamental topic which has been a matter of discussion in the last decades. The present paper is devoted to the experimental analysis of free and impinging jets with particular attention on the effect of an impinging surface on screech tones. The acoustics is studied using free-field microphones, while Particle Image Velocimetry is used to investigate the velocity field. The analysis of acquired data allowed to verify and explain the coupling between acoustic discrete tones and mean and fluctuating flow velocities.
Barrierless electronic relaxation in solution: An analytically solvable model
Authors: Chakraborty Aniruddha
Published: September 2013

We propose an analytical method for understanding the problem of electronic relaxation in solution, modelled by a particle undergoing diffusive motion under the influence of two potentials. The coupling between the two potentials is assumed to be represented by a Dirac delta function. The diffusive motion in this paper is described by the Smoluchowski equation. Our solution requires the knowledge of the Laplace transform of the Green's function for the motion in both the uncoupled potentials. Our model is more general than all the earlier models, because we are the first one to consider the effect of ground state potential energy surface explicitly.
Resilience of ultra-thin oxynitride films to percolative wear-out and reliability implications for high-κ stacks at low voltage stress
Authors: Raghavan Nagarajan , Padovani Andrea , Li Xiang , Wu Xing , Lip Lo Vui , Bosman Michel , Larcher Luca , Leong Pey Kin
Published: September 2013

Localized progressive wear-out and degradation of ultra-thin dielectrics around the oxygen vacancy percolation path formed during accelerated time dependent dielectric breakdown tests is a well-known phenomenon documented for silicon oxynitride (SiON) based gate stacks in metal oxide semiconductor field effect transistors. This progressive or post breakdown stage involves an initial phase characterized by “digital” random telegraph noise fluctuations followed by the wear-out of the percolation path, which results in an “analog” increase in the leakage current, culminating in a thermal runaway and hard breakdown. The relative contribution of the digital and analog phases of degradation at very low voltage stress in ultra-thin SiON (16 Å´) is yet to be fully investigated, which represents the core of this study. We investigate the wear-out process by combining electrical and physical analysis evidences with modeling and simulation results using Kinetic Monte Carlo defect generation and multi-phonon trap assisted tunneling (PTAT) models. We show that the transition from the digital to the analog regime is governed by a critical voltage (VCRIT), which determines the reliability margin in the post breakdown phase. Our results have a significant impact on the post-breakdown operational reliability of SiON and advanced high-κ–SiOx interfacial layer gate stacks, wherein the SiOx layer seems to be the weakest link for percolation event.
Multi-field characteristics and eigenmode spatial structure of geodesic acoustic modes in DIII-D L-mode plasmas
Authors: Wang G. , Peebles W. A. , Rhodes T. L. , Austin M. E. , Yan Z. , McKee G. R. , La Haye R. J. , Burrell K. H. , Doyle E. J. , Hillesheim J. C. , Lanctot M. J. , Nazikian R. , Petty C. C. , Schmitz L. , Smith S. , Strait E. J. , Van Zeeland M. , Zeng L.
Published: September 2013

The geodesic acoustic mode (GAM), a coherent form of the zonal flow, plays a critical role in turbulence regulation and cross-magnetic-field transport. In the DIII-D tokamak, unique information on multi-field characteristics and radial structure of eigenmode GAMs has been measured. Two simultaneous and distinct, radially overlapping eigenmode GAMs (i.e., constant frequency vs. radius) have been observed in the poloidal E×B flow in L-mode plasmas. As the plasma transitions from an L-mode to an Ohmic regime, one of these eigenmode GAMs becomes a continuum GAM (frequency responds to local parameters), while the second decays below the noise level. The eigenmode GAMs occupy a radial range of ρ = 0.6–0.8 and 0.75–0.95, respectively. In addition, oscillations at the GAM frequency are observed for the first time in multiple plasma parameters, including ne, Te, and Bθ. The magnitude of T̃e/Te at the GAM frequency (the magnitude is similar to that of ñe/ne) and measured ne–Te cross-phase (∼140° at the GAM frequency) together indicate that the GAM pressure perturbation is not determined solely by ñe. The magnetic GAM behavior, a feature only rarely reported, is significantly stronger (×18) on the high-field side of the tokamak, suggesting an anti-ballooning nature. Finally, the GAM is also observed to directly modify intermediate-wavenumber ñe levels (kρs ∼ 1.1). The simultaneous temperature, density, flow fluctuations, density-temperature cross-phase, and magnetic behavior present a new perspective on the underlying physics of the GAM.
A numerical investigation on the ground effect of a flapping-flying bird
Authors: Su Jian-Yuan , Tang Jhen-Han , Wang Ching-Hua , Yang Jing-Tang
Published: September 2013

The flight of a small bird under the influence of the ground effect is numerically investigated with a complete three-dimensional model including the bird's body and wings. The flight mode is not the conventional steady gliding flight but an unsteady flight consisting of flapping, twisting, and folding motions. As the bird approaches the ground, the average lift force gradually increases while the average drag force decreases. At a particular distance, the average lift force increases by approximately 47%, whereas the average drag force decreases by nearly 20%, relative to the absence of the ground effect. Because of the ground, the improved aerodynamic performance in flapping flight is much more significant than in steady flight, in which the modification of the lift-drag ratio is typically less than 10%. On the basis of the flow field, regardless of the presence or absence of the ground, there exists no evidence for an obstruction of a wing-tip vortex, which is a remarkable phenomenon and accounts for the improved performance in steady flight. The extent of the region of high pressure beneath the wing in the near-ground case seems to surpass that in the far-ground case, accounting for the greater lift and thrust forces in the near-ground case. This air cushion beneath the wing, known as the cram effect, is the dominant factor of the ground effect on a flapping bird.
Magnetic reconnection mediated by hyper-resistive plasmoid instability
Authors: Huang Yi-Min , Bhattacharjee A. , Forbes Terry G.
Published: September 2013

Magnetic reconnection mediated by the hyper-resistive plasmoid instability is studied with both linear analysis and nonlinear simulations. The linear growth rate is found to scale as SH1/6 with respect to the hyper-resistive Lundquist number SH≡L3VA/ηH, where L is the system size, VA is the Alfvén velocity, and ηH is the hyper-resistivity. In the nonlinear regime, reconnection rate becomes nearly independent of SH, the number of plasmoids scales as SH1/2, and the secondary current sheet length and width both scale as SH−1/2. These scalings are consistent with a heuristic argument assuming secondary current sheets are close to marginal stability. The distribution of plasmoids as a function of the enclosed flux ψ is found to obey a ψ−1 power law over an extended range, followed by a rapid fall off for large plasmoids. These results are compared with those from resistive magnetohydrodynamic studies.
Generalization of the classical xyz-polarization analysis technique to out-of-plane and inelastic scattering
Authors: Ehlers G. , Stewart J. R. , Wildes A. R. , Deen P. P. , Andersen K. H.
Published: September 2013

The technique of longitudinal (“xyz”) polarization analysis has been used successfully for many years to study disordered magnetic materials in thermal and cold neutron diffraction experiments. The technique allows the simultaneous and unambiguous separation of the nuclear, magnetic, and nuclear spin-incoherent contributions to the scattering. The technical advances seen in recent years, such as the availability of polarized 3He analyzer cells to cover a large detector solid angle, the ability to detect out-of-plane scattering in a multi-detector, and a significant increase of the usable beam divergence, call for a generalization of the method. A general treatment of the formalism for carrying out neutron polarization analysis will be given in this paper, which describes a possible method of usage at a future, modern diffractometer or inelastic spectrometer with large area multi-detector coverage.
Carbon nanotube coated fiber Bragg grating for photomechanical optic modulator
Authors: Shivananju B. N. , Suri Ashish , Asokan Sundarrajan , Misra Abha
Published: September 2013

We have demonstrated novel concept of utilizing the photomechanical actuation in carbon nanotubes (CNTs) to tune and reversibly switch the Bragg wavelength. When fiber Bragg grating coated with CNTs (CNT-FBG) is exposed externally to a wide range of optical wavelengths, e.g., ultraviolet to infrared (0.2–200 μm), a strain is induced in the CNTs which alters the grating pitch and refractive index in the CNT-FBG system resulting in a shift in the Bragg wavelength. This novel approach will find applications in telecommunication, sensors and actuators, and also for real time monitoring of the photomechanical actuation in nanoscale materials.
Klein tunneling in graphene systems under the influence of magnetic field
Authors: Bala Kumar S. , Jalil M. B. A. , Tan S. G.
Published: September 2013

We study Klein tunneling across a PN junction in monolayer graphene (MLG) and the AB-bilayer graphene (BLG) under the effect of a perpendicular magnetic-field (B-field). In the Klein tunneling process, normally incident electrons in MLG (BLG) are fully transmissive (reflective) upon hitting the junction barrier. When a finite B-field is applied, transmission of the normally incident electrons is suppressed in MLG over an energy range around the PN barrier height, effectively opening an energy gap. This suppression may be attributed to the magnetic deflection arising from Lorentz force, which shifts the transmission profile of the device in the transverse direction.
Role of inhomogeneous cation distribution in magnetic enhancement of nanosized Ni0.35Zn0.65Fe2O4: A structural, magnetic, and hyperfine study
Authors: Dey S. , Dey S. K. , Ghosh B. , Dasgupta P. , Poddar A. , Reddy V. R. , Kumar S.
Published: September 2013

In this paper, we report the structural, microstructural, and magnetic properties of nanosized (particle size ranging from 20 to 30 nm) Ni0.35Zn0.65Fe2O4 (MA4) system synthesized via mechanochemical route followed by annealing. The Rietveld refinement is used for the first time to precisely resolve the crystal structure of a ferrite system at nanoscale. MA4 is a cubic spinel of Fd3¯m symmetry. According to XRD and HRTEM studies, it is a well crystalline sample which possesses large microstrain. In spite of its nanometric size, MA4 has displayed some notably distinct magnetic properties like, enhancement of magnetization (64 emu g−1 at 15 K), magnetic order, magnetic ordering temperature, coercivity (1000 Oe at 15 K), magnetic anisotropy energy, and reduction of superparamagnetic relaxation compared with its counterparts synthesized by chemical route. It exhibits clear hysteresis loop (HC = 50 Oe) at 300 K and ferrimagnetic ordering below the blocking temperature (∼250 K). These improvements in magnetic properties of the system are likely to be very helpful for its technological applications. Again, particles in the sample possess a ferrimagnetically aligned core (with small canting) surrounded by a magnetically disordered shell with canted spin structure. The magnetically disordered surface region of MA4 has an equilibrium cation distribution, whereas the ferrimagnetic core region possesses a nonequilibrium cation distribution. Moreover, the infield Mössbauer spectroscopic study reveals that the nearest neighbor ion configuration about [B] site Fe3+ ions is not identical. Thus, there is local chemical inhomogeneity in the sample. The cation redistribution, chemical inhomogeneity, lattice strain are identified as the causes for magnetic enhancement in MA4.
Characteristics of plasma generated by hypervelocity impact
Authors: Song Weidong , Li Jianqiao , Ning Jianguo
Published: September 2013

The characteristics of plasma generated by hypervelocity impact were studied through both theoretical analysis and numerical simulation. Based on thermodynamics and statistical physics, a thermal ionization model was proposed to explore the relationships of ionization degree and plasma conductivity to temperature with consideration of the velocity distribution law in the thermodynamic equilibrium state. In order to derive the temperature, internal energy, and density of the plasma generated by the impact for the above relationships, a 3-D model for the impact of an aluminum spherical projectile on an aluminum target was established and five cases with different impact angles were numerically simulated. Then, the temperature calculated from the internal energy and the Thomas Fermi (TF) model, the internal energy and the density of the plasma were put into the function of the ionization degree to study the characteristics of plasma. Finally, based on the experimental data, a good agreement was obtained between the theoretical predictions and the experimental results, and the feasibility of this theoretical model was verified.
Dust-acoustic solitary structures in a magnetized dusty plasma with two-temperature nonextensive electrons
Authors: Emamuddin M. , Yasmin S. , Asaduzzaman M. , Mamun A. A.
Published: September 2013

The nonlinear propagation of dust-acoustic (DA) waves in an obliquely propagating magnetized dusty plasma, containing nonextensively distributed electrons of distinct temperatures (namely lower and higher temperature nonextensive electrons), negatively charged mobile dust grains, and Maxwellian ions, is rigorously studied and analyzed by deriving the Zakharov-Kuznetsov equation. It is found that the characteristics of the DA solitary waves (DASWs) are significantly modified by the external magnetic field, obliqueness of the system, nonextensivity of the electrons, electron temperature-ratios, and the respective number densities of two species of electrons. The results obtained from this analysis can be employed in understanding and treating the structures and the characteristics of DASWs both in laboratory and astrophysical plasma system.
Metal-free low-loss negative refraction in the mid-infrared region
Authors: Liu X. L. , Zhang Z. M.
Published: September 2013

Low-loss all-angle negative refraction is predicted in the mid-infrared region based on doped-silicon nanowire arrays. Loss-enhanced transmission and absence of resonances account for the broadband high figure of merit (FOM), which could be an order of magnitude greater than those reported previously for multilayered metamaterials. At oblique incidence, FOM is found to improve with increasing loss and the physical insight of this counter-intuitive trend is provided. The proposed structure uses doped silicon that is abundant, cheap, nontoxic, and can be fabricated with available processing technology. Furthermore, good tunability can be achieved by varying the doping concentration and volume filling ratio.
Analysis of temperature-dependent electrical characteristics in amorphous In-Ga-Zn-O thin-film transistors using gated-four-probe measurements
Authors: Jeong Jaewook , Jun Lee Gwang , Kim Joonwoo , Moon Jeong Soon , Kim Jung-Hye
Published: September 2013

We analyzed the temperature-dependent electrical characteristics of amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) using a gated-four-probe method (GFP) with temperatures ranging from 93 to 373 K. The intrinsic field-effect mobility and source/drain parasitic resistance were separately extracted using the GFP method. We found that temperature-dependent transfer characteristics originated from the temperature-dependent intrinsic field-effect mobility of the a-IGZO TFTs. The parasitic resistance was also correlated with the intrinsic-field effect mobility, which decreases as the intrinsic field-effect mobility increases, indicating that access parasitic resistance originated from bulk regions rather than metal/semiconductor junction barrier is a key factor to determine the parasitic resistance of a-IGZO TFTs.
Intensive suppression of thermal conductivity in Nd0.6Fe2Co2Sb12-xGex through spontaneous precipitates
Authors: Zhang Long , Duan Fenfen , Li Xiaodong , Yan Xinlin , Hu Wentao , Wang Limin , Liu Zhongyuan , Tian Yongjun , Xu Bo
Published: September 2013

The best p-type skutterudites are all Fe-rich and show larger coefficient of thermal expansion than CoSb3-based n-type skutterudites, which deteriorate the reliability of thermoelectric couples constituted by p- and n-skutterudites. In this study, we synthesize Nd0.6Fe2Co2Sb12-xGex (0≤x≤1) with equal amounts of Fe and Co. Microstructure analysis reveals a unique microstructure of precipitate phases, including nanoprecipitates in skutterudite matrix, structurally imperfect nanoparticles (less than 100 nm), and unprecedented thin-layer coverings about 10 nm thick. Such rich microstructures dominate the scattering of phonons with full-length scale and remarkably suppress the lattice thermal conductivity. As a result, ZT for Nd0.6Fe2Co2Sb11.7Ge0.3 is 50% improved compared with that of a Ge free sample even with a moderately decreased power factor.
Evaluation of the mobility-lifetime product in CdTe and CdZnTe detectors by the transient-current technique
Authors: Uxa Štěpán , Grill Roman , Belas Eduard
Published: September 2013

New methods for evaluation of mobility-lifetime product (μτ) in polarized planar CdTe and CdZnTe detectors are presented. We combined the transient-current technique measurements with the measurements of the charge-collection efficiency and developed two iterative procedures for calculating μτ and mobility, μ, both taking into account the actual profile of the electric field in a detector. Their applicability is demonstrated on both the simulated and existing experimental data. The cases in which these methods are preferred to the common procedures based on the Hecht equation are widely discussed. We demonstrate that neglecting the detector's polarization can lead to underestimation of real μτ, thus negatively affecting the interpretation of particular measurements.
An analytical model for bio-electronic organic field-effect transistor sensors
Authors: Macchia Eleonora , Giordano Francesco , Magliulo Maria , Palazzo Gerardo , Torsi Luisa
Published: September 2013

A model for the electrical characteristics of Functional-Bio-Interlayer Organic Field-Effect Transistors (FBI-OFETs) electronic sensors is here proposed. Specifically, the output current-voltage characteristics of a streptavidin (SA) embedding FBI-OFET are modeled by means of the analytical equations of an enhancement mode p-channel OFET modified according to an ad hoc designed equivalent circuit that is also independently simulated with pspice. An excellent agreement between the model and the experimental current-voltage output characteristics has been found upon exposure to 5 nM of biotin. A good agreement is also found with the SA OFET parameters graphically extracted from the device transfer I-V curves.
Superfast oxygen exchange kinetics on highly epitaxial LaBaCo2O5+δ thin films for intermediate temperature solid oxide fuel cells
Authors: Liu Jian , Collins Gregory , Liu Ming , Chen Chonglin
Published: September 2013

Superfast chemical dynamics on highly epitaxial LaBaCo2O5+δ (LBCO) heterostructures were systematically studied with symmetric half-cell LBCO/Gd0.2Ce0.8O2 (GCO):Y0.08Zr0.92O2 (YSZ)/LBCO heterostructures on (001) LaAlO3. The electrochemical impedance spectroscopy measurements reveal that the LBCO film electrodes have an ultralow polarization resistance as low as 0.11 Ω cm2 at 600 °C in air, a superfast surface exchange coefficient of 0.017 cm/s at 600°, and an extremely low activation energy value of 0.49 eV. These excellent physical chemistry properties and superfast chemical dynamics on the highly epitaxial LBCO thin films are considered to be somewhat related to the structure entropy of the nano ordered oxygen vacancy structure.
Room-temperature ferroelectricity in SrTiO3 nanodots array formed by an ac-bias field
Authors: Yeog Son Jong , Lee Jung-Hoon , Myung Jang Hyun
Published: September 2013

In its pure unstressed form, SrTiO3 (STO) remains quantum paraelectric down to 0 K. Herein, we demonstrate the ferroelectric STO nanodots array embodied by exploiting the idea of oxygen-vacancy-promoted ferroelectricity. First-principles calculations clearly support this idea. To practically activate the oxygen vacancies needed for the revelation of room-temperature ferroelectricity, we have applied an ac-bias field with various switching cycles at a conducting atomic-force-microscope tip. The STO nanodots with optimum polarization-switching characteristics have been implemented by suitably trading-off between the oxygen-vacancy-promoted polarization and the increasing leakage current with the switching cycle.
Pressure induced variation of second harmonic efficiency of K3B6O10Cl
Authors: Wang Hui , Kong Lingyao , Zhao Xiaoyan , Lv Zhenlong , Li Tongwei , Ju Wei Wei , You Jinghan , Bai Ying
Published: September 2013

K3B6O10Cl is a perovskite-like nonlinear optical (NLO) crystal, which exhibits large second harmonic generation (SHG) response. Based on density-functional theory, we investigate the influence of pressure on SHG tensor of K3B6O10Cl. At zero pressure, the non-centrosymmetric distortion of K3B6O10Cl from BO4 tetrahedron results in the similar SHG tensor to β-BaB2O4 (BBO). At 50 GPa, the ClK6 octahedron distortion of K3B6O10Cl becomes the main source of SHG and give similar SHG tensor to LiNbO3. Therefore, pressure induces K3B6O10Cl from a BBO-like NLO material to a LiNbO3-like NLO material.
Edge and substrate-induced bandgap in zigzag graphene nanoribbons on the hexagonal nitride boron 8-ZGNR/h-BN(0001)
Authors: Ilyasov V. V. , Meshi B. C. , Nguyen V. C. , Ershov I. V. , Nguyen D. C.
Published: September 2013

The results of DFT (GGA-PBEsol) and DFT(PBE)-D2 study of the band structure of zigzag graphene nanoribbons on hexagonal nitride boron 8-ZGNR/h-BN(0001) are presented, suitable as potential base for new materials for spintronics. It offers a study of regularities in the changes of the valence band electron structure and the induction of the energy gap in the series 8-ZGNR → 8-ZGNR/h-BN(0001) → graphene/h-BN(0001). The peculiarities of the spin state at the Fermi level, the roles of the edge effect and the effect of substrate in formation of the band gap in 8-ZGNR/h-BN(0001) system are discussed. Our calculations shown that vdW-correction plays an important role in the adsorption of GNR on h-BN and results in reduction of the interplanar distances in equilibrium systems ZGNRs/h-BN(0001). As a result of the structural changes we have obtained new values of the energy gap in the 8-ZGNR-AF and 8-ZGNR-AF/h-BN(0001) systems. The paper demonstrates appearance of 600 meV energy gap in the 8-ZGNR/h-BN(0001) interface. The contributions of nanoribbon edges and the substrate in formation of the gap have been differentiated for the first time. The estimations of local magnetic moments on carbon atoms are made. Shown that in case of ferromagnetic ordering substrate presense causes insignificant splitting of the bands. The splitting reached only (14-28 meV). Since the electronic states of a suspended GNR in point (k=π) are degenerate near the Fermi level, we can assume that the above splitting in 8-ZGNR/h-BN(0001) is only determined by the contribution of the h-BN(0001) substrate.
The carcass quality, meat quality and sensory characteristics of broilers raised on diets containing either Musca domestica larvae meal, fish meal or soya bean meal as the main protein source
Authors: Pieterse E. , Pretorius Q. , Hoffman L. C. , Drew D. W.
Published: September 2013

The effects of Musca domestica (common house fly) larvae meal (magmeal) on the meat quality of broiler chickens were investigated in a trial consisting of three isonitrogenous and isoenergetic treatment diets containing either 10% fish meal, 10% M. domestica larvae meal or a control diet with soya bean meal as the protein source. Chicks that received either the 10% M. domestica larvae meal or 10% fish meal produced significantly heavier carcasses and had a higher breast-meat yield than did the control chicks. Sensory attributes evaluated by a trained sensory panel included chicken aroma, metallic aroma, initial juiciness, chicken flavour, sustained juiciness, metallic aftertaste, toughness and mealiness. The samples were judged to have a prominent chicken aroma but a less prominent chicken flavour. Although the samples had a moderate initial juiciness, they did not have a sustained juiciness except for the larvae-fed samples, which had higher sustained juiciness values; all samples were perceived as tender; fishmeal-fed samples were judged more mealy than larvae-fed samples, with the control being intermediary; larvae-fed samples had higher metallic aroma and aftertaste values, although these values were low and unlikely to be detected by consumers. Comparison of meat-quality characteristics showed no treatment differences for breast- and thigh-muscle colour, pH, water holding capacity or cooking losses. Significant differences were observed for drip loss, with the lowest drip loss reported for the larvae meal-fed samples, followed by the control diet and the highest for fish meal-fed samples. It is concluded that the inclusion of larvae meal into the diets of broilers will have positive rather than any detrimental effects on most carcass, meat and sensory characteristics.
Matrix Metalloproteinase Biosensor Based on a Porous Silicon Reflector
Authors: Krismastuti Fransiska S. H. , Pace Stephanie , Melville Elizabeth , Cowin Allison , Dargaville Tim R. , Voelcker Nicolas H.
Published: September 2013

Matrix metalloproteinases (MMP) are proteolytic enzymes important to wound healing. In non-healing wounds, it has been suggested that MMP levels become dysfunctional, hence it is of great interest to develop sensors to detect MMP biomarkers. This study presents the development of a label-free optical MMP biosensor based on a functionalised porous silicon (pSi) thin film. The biosensor is fabricated by immobilising a peptidomimetic MMP inhibitor in the porous layer using hydrosilylation followed by amide coupling. The binding of MMP to the immobilised inhibitor translates into a change of effective optical thickness over time. We investigated the effect of surface functionalisation on the stability of the pSi surface and evaluated sensing performance. We successfully demonstrated MMP detection in buffer solution and human wound fluid at physiologically relevant concentrations. This biosensor may find application as a point-of-care device that is prognostic of the healing trajectory of chronic wounds.
Pheromone responsiveness threshold depends on temporal integration by antennal lobe projection neurons
Authors: Tabuchi Masashi , Sakurai Takeshi , Mitsuno Hidefumi , Namiki Shigehiro , Minegishi Ryo , Shiotsuki Takahiro , Uchino Keiro , Sezutsu Hideki , Tamura Toshiki , Haupt Stephan Shuichi , Nakatani Kei , Kanzaki Ryohei
Published: September 2013

Significance

The olfactory system of male moths exhibits the ability to detect minute amounts of sex pheromones. How this extreme sensitivity is achieved remains unclear. Using optogenetic techniques to activate a pheromone-responsive olfactory receptor neuron, our results reveal that weak olfactory inputs, but not strong inputs, are temporally integrated in second-order projection neurons to promote behavioral responsiveness. Furthermore, temporal integration of strong olfactory inputs is inhibited by GABAergic mechanisms, indicating that GABA signaling suppresses the amplification of strong stimuli. The timescale of this temporal integration corresponds well to the temporal dynamics of odor signals in the natural environment, suggesting that the olfactory systems of male moths use this mechanism to detect weak pheromone signals in the air.
Naming Fluency in Dyslexic and Nondyslexic Readers: Differential Effects of Visual Crowding in Foveal, Parafoveal, and Peripheral Vision
Authors: Moll Kristina , Jones Manon
Published: September 2013

Reading fluency is often indexed by performance on rapid automatized naming (RAN) tasks, which are known to reflect speed of access to lexical codes. We used eye tracking to investigate visual influences on naming fluency. Specifically, we examined how visual crowding affects fluency in a RAN-letters task on an item-by-item basis, by systematically manipulating the interletter spacing of items, such that upcoming letters in the array were viewed in the fovea, parafovea, or periphery relative to a given fixated letter. All lexical information was kept constant. Nondyslexic readers’ gaze durations were longer in foveal than in parafoveal and peripheral trials, indicating that visual crowding slows processing even for fluent readers. Dyslexics’ gaze durations were longer in foveal and parafoveal trials than in peripheral trials. Our results suggest that for dyslexic readers, influences of crowding on naming speed extend to a broader visual span (to parafoveal vision) than that for nondyslexic readers, but do not extend as far as peripheral vision. The findings extend previous research by elucidating the different visual spans within which crowding operates for dyslexic and nondyslexic readers in an online fluency task.
Identification and characterization of multiple novel Rab–myosin Va interactions
Authors: Lindsay Andrew J. , Jollivet Florence , Horgan Conor P. , Khan Amir R. , Raposo Graça , McCaffrey Mary W. , Goud Bruno
Published: September 2013

Myosin Va is a widely expressed actin-based motor protein that binds members of the Rab GTPase family (3A, 8A, 10, 11A, 27A) and is implicated in many intracellular trafficking processes. To our knowledge, myosin Va has not been tested in a systematic screen for interactions with the entire Rab GTPase family. To that end, we report a yeast two-hybrid screen of all human Rabs for myosin Va-binding ability and reveal 10 novel interactions (3B, 3C, 3D, 6A, 6A′, 6B, 11B, 14, 25, 39B), which include interactions with three new Rab subfamilies (Rab6, Rab14, Rab39B). Of interest, myosin Va interacts with only a subset of the Rabs associated with the endocytic recycling and post-Golgi secretory systems. We demonstrate that myosin Va has three distinct Rab-binding domains on disparate regions of the motor (central stalk, an alternatively spliced exon, and the globular tail). Although the total pool of myosin Va is shared by several Rabs, Rab10 and Rab11 appear to be the major determinants of its recruitment to intracellular membranes. We also present evidence that myosin Va is necessary for maintaining a peripheral distribution of Rab11- and Rab14-positive endosomes.
The Nature of Philosophical Argument
Authors: Matilal Bimal Krishna
Published: September 2013

This chapter aims to provide a somewhat broader perspective of Indian philosophy in the background of which philosophical arguments regarding perception and knowledge were developed. It deals with issues whose relevance with the main theme of this book may not be immediately obvious, but nevertheless the importance of these issues for forming a proper conception of what Indian philosophy is all about. The first section of this chapter contrasts philosophy with soteriology. The second section discusses the Nyāya project of philosophical inquiry. The third section considers debate and dialectic. The term ‘dialectic’ refers to the art of philosophic disputation in ancient India. The last section contrasts negation and refutation.