bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanical strains modulate the carrier behaviors of organic field effect transistors
Authors: Yamamoto Tetsuya , Abe Youhei , Taguchi Dai , Manaka Takaaki , Iwamoto Mitsumasa
Published: March 2012

We theoretically analyze carrier transports in an organic field effect transistor that is subjected to mechanical strains. These strains change the density of carriers that are accumulated at the channel by the Maxwell-Wagner mechanism and thus modulate drain currents. These effects of strains are characterized by three parameters α, μ1, and μ2, which represent the changes of the dielectric constant of gate insulators and channel mobilities. These charge density modulations are different from piezoelectric effects, and accumulated charge density depends on both applied gate voltages and applied strains.
Development of the large neutron imaging system for inertial confinement fusion experiments
Authors: Caillaud T. , Landoas O. , Briat M. , Kime S. , Rossé B. , Thfoin I. , Bourgade J. L. , Disdier L. , Glebov V. Yu. , Marshall F. J. , Sangster T. C.
Published: March 2012

Inertial confinement fusion (ICF) requires a high resolution (∼10 μm) neutron imaging system to observe deuterium and tritium (DT) core implosion asymmetries. A new large (150 mm entrance diameter: scaled for Laser MégaJoule [P. A. Holstein, F. Chaland, C. Charpin, J. M. Dufour, H. Dumont, J. Giorla, L. Hallo, S. Laffite, G. Malinie, Y. Saillard, G. Schurtz, M. Vandenboomgaerde, and F. Wagon, Laser and Particle Beams 17, 403 (1999)10.1017/S0263034699173087]) neutron imaging detector has been developed for such ICF experiments. The detector has been fully characterized using a linear accelerator and a 60Co γ-ray source. A penumbral aperture was used to observe DT-gas-filled target implosions performed on the OMEGA laser facility. [T. R. Boehly, D. L. Brown, R. S. Craxton, R. L. Keck, J. P. Knauer, J. H. Kelly, T. J. Kessler, S. A. Kumpan, S. J. Loucks, S. A. Letzring, F. J. Marshall, R. L. McCrory, S. F. B. Morse, W. Seka, J. M. Soures, and C. P. Verdon, Opt. Commun. 133, 495 (1997)10.1016/S0030-4018(96)00325-2] Neutron core images of 14 MeV with a resolution of 15 μm were obtained and are compared to x-ray images of comparable resolution.
Tunable spin manipulation in a quantum dot embedded in an Aharonov-Bohm interferometer
Authors: Jiang Cui , Gong Wei-Jiang , Wei Guo-Zhu
Published: March 2012

In this paper, we study the electron properties of an Aharonov-Bohm interferometer with an embedded quantum dot (QD) by considering the leads of spin bias. As a result, it is found that a local magnetic flux through the structure can efficiently induce spin accumulation in the QD, unaccompanied by any charge transfer, and it shows that the direction and magnitude of the spin accumulation are tightly dependent on the interplay between the magnetic flux and spin bias. Based on the calculated results, we propose such a structure to be a candidate of the spin-manipulating device.
A practical guide for the fabrication of microfluidic devices using glass and silicon
Authors: Iliescu Ciprian , Taylor Hayden , Avram Marioara , Miao Jianmin , Franssila Sami
Published: March 2012

This paper describes the main protocols that are used for fabricating microfluidic devices from glass and silicon. Methods for micropatterning glass and silicon are surveyed, and their limitations are discussed. Bonding methods that can be used for joining these materials are summarized and key process parameters are indicated. The paper also outlines techniques for forming electrical connections between microfluidic devices and external circuits. A framework is proposed for the synthesis of a complete glass/silicon device fabrication flow.
Exact quantum scattering study of the H + HS reaction on a new ab initio potential energy surface H2S (3A
″)
Authors: Lv Shuang-Jiang , Zhang Pei-Yu , Han Ke-Li , He Guo-Zhong
Published: March 2012

We present an exact quantum dynamical study and quasi-classical trajectory (QCT) calculations for the exchange and abstraction processes for the H + HS reaction. These calculations were based on a newly constructed high-quality potential energy surface for the lowest triplet state of H2S (3A″). The ab initio single-point energies were computed using complete active space self-consistent field and multi-reference configuration interaction method with a basis set of aug-cc-pV5Z. The time-dependent wave packet (TDWP) method was used to calculate the total reaction probabilities and integral cross sections over the collision energy (Ecol) range of 0.0−2.0 eV for the reactant HS initially at the ground state and the first vibrationally excited state. It was found that the initial vibrational excitation of HS enhances both abstraction and exchange processes. In addition, a good agreement is found between QCT and TDWP reaction probabilities at the total momentum J = 0 as a function of collision energy for the H + HS (v = 0, j = 0) reaction.
Phase transition in porous electrodes. II. Effect of asymmetry in the ion size
Authors: Kiyohara Kenji , Shioyama Hiroshi , Sugino Takushi , Asaka Kinji
Published: March 2012

The electrochemical thermodynamics of electrolytes in porous electrodes is qualitatively different from that in the bulk with planar electrodes when the pore size is comparable to the size of the electrolyte ions. In this study, the effect of the ion size asymmetry on the thermodynamics in porous electrodes was studied by using Monte Carlo simulation. We used the electrolyte ions for which the size of the cations and that of anions is different. Due to the asymmetry in the ion size, the ionic structure and the way the surface charge is distributed on the electrode surfaces were found to be qualitatively different in the cathode and in the anode. In particular, for some ranges of applied voltage, the distribution of the surface charge induced on the electrode planes shows inhomogeneity, which is not intrinsic to the structure of the porous electrodes. The transition from the homogeneous to the inhomogeneous distribution of surface charge on changing the voltage is a second order phase transition.
Transport coefficients in strongly coupled plasmas
Authors: Baalrud Scott D.
Published: March 2012

Transport coefficients for Coulomb collision processes in correlated plasmas are calculated within the binary collision approximation. Considering plasmas with flowing Maxwellian distributions and Debye screened particle potentials as an example, it is shown that the friction and energy exchange densities are similar to those in weakly coupled plasmas, but a generalized Coulomb logarithm, Ξ(Λ), is required. This asymptotes to lnΛ in the weakly coupled limit, but is significantly modified when Λ≲102 due to large angle collisions. The results show excellent agreement with molecular dynamics simulations of temperature relaxation.
Flat pancake distant dipolar fields for enhancement of intermolecular multiple-quantum coherence signals
Authors: Cai Congbo , Lin Yulan , Cai Shuhui , Sun Huijun , Zhong Jianhui , Chen Zhong
Published: March 2012

Intermolecular multiple-quantum coherences (iMQCs) originated from distant dipolar field (DDF) possess some appealing unique properties for magnetic resonance imaging (MRI). DDF is usually induced with continuous wave (i.e., sine- or square-wave) magnetization modulation in the whole sample. In this article, a spatially localized and enhanced DDF was optimally tailored in a thin slice with an adiabatic inversion pulse. Evidence was provided to show that careful tailoring of the spatially localized DDF can generate highly efficient iMQC signals, with more than two-fold enhancement compared to the conventional sine-wave magnetization modulation method, and 1.5 times of that with the square-wave modulation under the similar condition. Theoretical predictions, simulation results, and experimental verifications agree well with each other. Practical implementation of this approach for efficient iMQC MRI was explored.
Coupling of translational and rotational motion in chiral liquids in electromagnetic and circularly polarised electric fields
Authors: English Niall J. , Kusalik Peter G. , Woods Sarah A.
Published: March 2012

Non-equilibrium molecular dynamics simulations of R and S enantiomers of 1,1-chlorofluoroethane, both for pure liquids and racemic mixtures, have been performed at 298 K in the absence and presence of both electromagnetic (e/m) and circularly polarised electric (CP) fields of varying frequency (100–2200 GHz) and intensity (0.025–0.2 V Å−1rms). Significant non-thermal field effects were noted in the coupling of rotational and translational motion; for instance, in microwave and far-infrared (MW/IR) e/m fields, marked increases in rotational and translational diffusion vis-à-vis the zero-field case took place at 0.025–0.1 V Å−1rms, with a reduction in translational diffusion vis-à-vis the zero-field case above 0.1 V Å−1rms above 100 GHz. This was due to enhanced direct coupling of rotational motion with the more intense e/m field at the ideal intrinsic rotational coupling frequency (approximately 700 GHz) leading to such rapidly oscillating rotational motion that extent of translational motion was effectively reduced. In the case of CP fields, rotational and translational diffusion was also enhanced for all intensities, particularly at approximately 700 GHz. For both MW/IR and CP fields, non-linear field effects were evident above around 0.1 V Å−1rms intensity, in terms of enhancements in translational and rotational motion. Simulation of 90–10 mol. % liquid mixtures of a Lennard–Jones solvent with R and S enantiomer-solutes in MW/IR and CP fields led to more limited promotion of rotational and translational diffusion, due primarily to increased frictional effects. For both e/m and CP fields, examination of the laboratory- and inertial-frame auto- and cross-correlation functions of velocity and angular velocity demonstrated the development of explicit coupling with the external fields at the applied frequencies, especially so in the more intense fields where nonlinear effects come into play. For racemic mixtures, elements of the laboratory- and inertial-frame velocity and angular velocity were found to couple with each other to a lesser extent.
Measuring nonadiabaticity of molecular quantum dynamics with quantum fidelity and with its efficient semiclassical approximation
Authors: Zimmermann Tomáš , Vaníček Jiří
Published: March 2012

We propose to measure nonadiabaticity of molecular quantum dynamics rigorously with the quantum fidelity between the Born-Oppenheimer and fully nonadiabatic dynamics. It is shown that this measure of nonadiabaticity applies in situations where other criteria, such as the energy gap criterion or the extent of population transfer, fail. We further propose to estimate this quantum fidelity efficiently with a generalization of the dephasing representation to multiple surfaces. Two variants of the multiple-surface dephasing representation (MSDR) are introduced, in which the nuclei are propagated either with the fewest-switches surface hopping or with the locally mean field dynamics (LMFD). The LMFD can be interpreted as the Ehrenfest dynamics of an ensemble of nuclear trajectories, and has been used previously in the nonadiabatic semiclassical initial value representation. In addition to propagating an ensemble of classical trajectories, the MSDR requires evaluating nonadiabatic couplings and solving the Schrödinger (or more generally, the quantum Liouville-von Neumann) equation for a single discrete degree of freedom. The MSDR can be also used in the diabatic basis to measure the importance of the diabatic couplings. The method is tested on three model problems introduced by Tully and on a two-surface model of dissociation of NaI.
Dielectrophoretic capture voltage spectrum for measurement of dielectric properties and separation of cancer cells
Authors: Wu Liqun , Lanry Yung Lin-Yue , Lim Kian-Meng
Published: March 2012

In this paper, a new dielectrophoresis (DEP) method based on capture voltage spectrum is proposed for measuring dielectric properties of biological cells. The capture voltage spectrum can be obtained from the balance of dielectrophoretic force and Stokes drag force acting on the cell in a microfluidic device with fluid flow and strip electrodes. The method was demonstrated with the measurement of dielectric properties of human colon cancer cells (HT-29 cells). From the capture voltage spectrum, the real part of Clausius–Mossotti factor of HT-29 cells for different frequencies of applied electric field was obtained. The dielectric properties of cell interior and plasma membrane were then estimated by using single-shell dielectric model. The cell interior permittivity and conductivity were found to be insensitive to changes in the conductivity of the medium in which the cells are suspended, but the measured permittivity and conductivity of cell membrane were found to increase with the increase of medium conductivity. In addition, the measurement of capture voltage spectrum was found to be useful in providing the optimum operating conditions for separating HT-29 cells from other cells (such as red blood cells) using dielectrophoresis.
Simple and compact capacitive voltage probe for measuring voltage impulses up to 0.5 MV
Authors: Pecquois R. , Pecastaing L. , de Ferron A. , Rivaletto M. , Pignolet P. , Novac B. M. , Smith I. R. , Adler R. J.
Published: March 2012

The paper describes a simple and compact 0.5 MV high-voltage capacitive probe developed in common by Université de Pau (France) and Loughborough University (UK). Design details are provided, together with a simple and straightforward methodology developed to assess the characteristics of high-voltage probes. The technique uses a 4 kV pulsed arrangement combined with results from a 2D electric field solver and a thorough PSpice circuit analysis. Finally, a practical example of high-voltage measurement performed using such a probe during the development phase of a high power microwave generator is provided.
Design of integrated III-nitride/non-III-nitride tandem photovoltaic devices
Authors: Toledo Nikholas G. , Friedman Daniel J. , Farrell Robert M. , Perl Emmett E. , (Tony) Lin Chieh-Ting , Bowers John E. , Speck James S. , Mishra Umesh K.
Published: March 2012

The integration of III-nitride and non-III-nitride materials for tandem solar cell applications can improve the efficiency of the photovoltaic device due to the added power contributed by the III-nitride top cell to that of high-efficiency multi-junction non-III-nitride solar cells if the device components are properly designed and optimized. The proposed tandem solar cell is comprised of a III-nitride top cell bonded to a non-III-nitride, series-constrained, multi-junction subcell. The top cell is electrically isolated, but optically coupled to the underlying subcell. The use of a III-nitride top cell is potentially beneficial when the top junction of a stand-alone non-III-nitride subcell generates more photocurrent than the limiting current of the non-III-nitride subcell. Light producing this excess current can either be redirected to the III-nitride top cell through high energy photon absorption, redirected to the lower junctions through layer thickness optimization, or a combination of both, resulting in improved total efficiency. When the non-III-nitride cell’s top junction is the limiting junction, the minimum power conversion efficiency that the III-nitride top cell must contribute should compensate for the spectrum filtered from the multi-junction subcell for this design to be useful. As the III-nitride absorption edge wavelength, λN, increases, the performance of the multi-junction subcell decreases due to spectral filtering. In the most common spectra of interest (AM1.5 G, AM1.5 D, and AM0), the technology to grow InGaN cells with λN < 520 nm is found to be sufficient for III-nitride top cell applications. The external quantum efficiency performance, however, of state-of-the-art InGaN solar cells still needs to be improved. The effects of surface/interface reflections are also presented. The management of these reflection issues determines the feasibility of the integrated III-nitride/non-III-nitride design to improve overall cell efficiency.
Evacuated tube solar heat pipe collector model and associated tests
Authors: Jafarkazemi Farzad , Abdi Hossein
Published: March 2012

In this paper, an evacuated solar heat pipe collector is investigated theoretically and experimentally. Heat transfer formulas were used for theoretical modeling, and a test method was adopted from ISO 9806-1 to compare the theoretical model with the experimental results. The collector efficiency and useful heat gain were compared between the theoretical and experimental methods. The effect of the working fluid flow rates and collector area were also investigated and discussed. The comparison shows that the theoretical model is in good agreement with the experimental results and is capable of predicting the efficiency, useful heat gain, and working fluid outlet temperature of an evacuated heat pipe collector with good accuracy.
Infrared spectra of CO2-doped hydrogen clusters, (H2)N–CO2
Authors: McKellar A. R. W.
Published: March 2012

Clusters of para-H2 and/or ortho-H2 containing a single carbon dioxide molecule are studied by high resolution infrared spectroscopy in the 2300 cm−1 region of the CO2 ν3 fundamental band. The (H2)N–CO2 clusters are formed in a pulsed supersonic jet expansion from a cooled nozzle and probed using a rapid scan tunable diode laser. Simple symmetric rotor type spectra are observed with little or no resolved K-structure, and prominent Q-branch features for ortho-H2 but not para-H2. Observed rotational constants and vibrational shifts are reported for ortho-H2 up to N = 7 and para-H2 up to N = 15, with the N > 7 assignments only made possible with the help of theoretical simulations. The para-H2 cluster with N = 12 shows clear evidence for superfluid effects, in good agreement with theory. The presence of larger clusters with N > 15 is evident in the spectra, but specific assignments are not possible. Mixed para- + ortho-H2 cluster transitions are well predicted by linear interpolation between corresponding pure cluster line positions.
On the standing waves for nonlinear Hartree equation with confining potential
Authors: Cao Pei , Wang Jing , Zou Wenming
Published: March 2012

We study the standing wave solutions for nonlinear Hartree equations. Of special interest to us is the existence and orbital stability of the standing wave solutions for the Hartree equation in the presence of confining potential. We establish the existence of two different notions of ground states via variation methods and orbital stability results for the corresponding standing wave solutions for focusing Hartree equations. The existence of the standing waves for defocusing Hartree equation is also considered.
Thermally induced error: Density limit for magnetic data storage
Authors: Evans R. F. L. , Chantrell R. W. , Nowak U. , Lyberatos A. , Richter H.-J.
Published: March 2012

Magnetic data storage is pervasive in the preservation of digital information, and the rapid pace of computer development requires ever more capacity. Increasing the storage density for magnetic hard disk drives requires a reduced bit size, previously thought to be limited by the thermal stability of the constituent magnetic grains. The limiting storage density in magnetic recording is investigated treating the writing of bits as a thermodynamic process. A “thermal writability” factor is introduced and it is shown that storage densities will be limited to 15 to 20 TBit/in2 unless technology can move beyond the currently available write field magnitudes.
Electron depletion and accumulation regions in n-type copper-hexadecafluoro-phthalocyanine and their effects on electronic properties
Authors: Wang Haibo , Liu Zengtao , Fai Lo Ming , Wai Ng Tsz , Yan Donghang , Lee Chun-Sing
Published: March 2012

We investigated interfacial electronic structures of organic/inorganic heterojunctions formed between copper-hexadecafluoro-phthalocyanine (F16CuPc) and molybdenum trioxide or lead monoxide by ultraviolet and x-ray photoemission spectroscopies. Obvious energy level bending in F16CuPc shows the formation of electron depletion and accumulation regions in its contact with molybdenum and lead oxides, respectively. Effects of these depletion/accumulation zones were studied via electronic characteristics of field-effect transistors constructed with these heterojunctions as active layers. Finally, a summary about the heterojunction including organic semiconductor (n-type and p-type) and metal oxide was given, which demonstrated that organic semiconductors can form various space charge regions like conventional inorganic semiconductors.
Thermal characterization of composites made up of magnetically aligned carbonyl iron particles in a polyester resin matrix
Authors: Medina-Esquivel R. A. , Zambrano-Arjona M. A. , Mendez-Gamboa J. A. , Yanez-Limon J. M. , Ordonez-Miranda J. , Alvarado-Gil J. J.
Published: March 2012

The thermal characterization of composites made up by magnetically aligned carbonyl iron micro-sized particles embedded in a polyester resin matrix is performed using photothermal radiometry technique. The measured experimental data show that the thermal conductivity and thermal diffusivity of the composite, in the direction of the applied magnetic field, increase with the concentration of the particles and are enhanced with respect to their corresponding values for a random distribution of the particles. This thermal enhancement has a maximum at a concentration of particles of 10% and is very low at small and high iron volume fractions, such that for particles concentrations of about 40%, the composite thermal conductivity reduces to its values for random particles. This behavior indicates that for high volume fractions, the effect of the microparticles concentration plays a dominant role over the effect of their alignment. It is shown that the thermal conductivity of the composite can be modeled in terms of the Nielsen model, under an appropriate parameterization of the form factor of the particles. The results of this work could be highly useful for improving the thermal performance of mechanical and electronic devices involving composite materials.
Steady state and transient electron transport properties of bulk dilute GaNxAs1−x
Authors: Naylor Daniel R. , Dyson Angela , Ridley Brian K.
Published: March 2012

Two valley ensemble Monte Carlo simulations have been performed to investigate the electronic transport properties of bulk GaNxAs1−x alloys where the nitrogen concentration x ≤ 0.02 (2%). We have investigated these properties using two separate approaches, 1) through simulation of GaAs using the standard Kane model with the addition of isolated and pair state nitrogen scattering mechanisms and 2) approximating the lower “mixed state” band that arises from the use of band-anticrossing model with an analytic function that implements the inflection point (for concentrations >1%). From the steady-state properties, we find that the nitrogen scattering model produces a better fit with other results, both theoretical and experimental. We also comment on the transient properties of GaNxAs1−x, noting that the velocity overshoot peaks are of a much lower velocity than is found in GaAs at comparable field strengths, and through the use of model 2, that negative effective mass states have a significant role in the transient behavior. We find that the system takes much longer to reach equilibrium when compared to bulk GaAs in both models, and through the use of model 2, there is a significant population of negative effective mass states when the system is subjected to higher fields.
Communication: Epistructural thermodynamics of soluble proteins
Authors: Fernández Ariel
Published: March 2012

The epistructural tension of a soluble protein is defined as the reversible work per unit area required to span the interfacial solvent envelope of the protein structure. It includes an entropic penalty term to account for losses in hydrogen-bonding coordination of interfacial water and is determined by a scalar field that indicates the expected coordination of a test water molecule at any given spatial location. An exhaustive analysis of structure-reported monomeric proteins reveals that disulfide bridges required to maintain structural integrity provide the thermodynamic counterbalance to the epistructural tension, yielding a tight linear correlation. Accordingly, deviations from the balance law correlate with the thermal denaturation free energies of proteins under reducing conditions. The picomolar-affinity toxin HsTX1 has the highest epistructural tension, while the metastable cellular form of the human prion protein PrPC represents the least tension-balanced protein.
Surface wave resonances supported on a square array of square metallic pillars
Authors: Berry S. J. , Campbell T. , Hibbins A. P. , Sambles J. R.
Published: March 2012

A family of transverse-magnetic surface waves is shown to be supported at microwave frequencies by a square array of subwavelength square cross-section metal pillars on a conducting ground plane. These surface waves are experimentally characterised with a collimated microwave beam apparatus that utilises a pair of two-dimensional parabolic mirrors positioned on the sample surface. The dispersion of the modes, each associated with a quantisation of the electromagnetic field in the depth of the slits, is fully characterised and compared with the predictions of finite element modelling.
Thermocapillary instabilities in an evaporating drop deposited onto a heated substrate
Authors: Sobac B. , Brutin D.
Published: March 2012

The present study is an experimental investigation regarding the evaporation of ethanol drops deposited onto a heated substrate in a partial wetting situation. The originality of this work is based on the simultaneous observation of the kinetics of evaporation, heat and mass transfers, the triple-line dynamic, and thermal motions inside the drop. The triple line recedes during the drop evaporation and a spontaneous development of thermal-convective instabilities driven by the evaporation are observed. These instabilities are interpreted as hydrothermal waves induced by surface tension gradient along the free surface. An infrared technique is used to investigate the temporal and spatial dynamics of the hydrothermal waves. Results reveal a non-linear evolution of the number of waves as well as several instability regimes. A complete description of the drop evaporation with the evidence of several phases is provided. The influence of geometrical and thermal parameters has been analyzed and raised scaling laws on hydrodynamic and energy transport. The drop evaporation appears to be characterized by a constant drop Nusselt number of a value 1.7 during all the process which highlights both the importance of conduction and convection in the energy transport in an evaporating drop.
ϕ-Derivations on operators on q-Fock space
Authors: Ji Un Cig , Kim Jae Hee
Published: March 2012

We study the q-creation and q-annihilation derivatives of operators on q-Fock space and then the derivatives are ϕ-derivations with respect to the q-Wick product, where ϕ is a *-homomorphism with respect to the q-Wick product, which provide interesting non-trivial examples of abstract ϕ-derivation.
Effect of grain boundary on the buckling of graphene nanoribbons
Authors: Neek-Amal M. , Peeters F. M.
Published: March 2012

The buckling of graphene nano-ribbons containing a grain boundary is studied using atomistic simulations where free and supported boundary conditions are invoked. We consider the buckling transition of two kinds of grain boundaries with special symmetry. When graphene contains a large angle grain boundary with θ = 21.8°, the buckling strains are larger than those of perfect graphene when the ribbons with free (supported) boundary condition are subjected to compressive tension parallel (perpendicular) to the grain boundary. This is opposite for the results of θ = 32.2°. The shape of the deformations of the buckled graphene nanoribbons depends on the boundary conditions, the presence of the particular used grain boundaries, and the direction of applied in-plane compressive tension.
Site-selective photoluminescence in thiol-capped gold nanoclusters
Authors: Lin T. N. , Liu C. H. , Shu G. W. , Shen J. L. , Lin C. A. J. , Chang W. H. , Wang H. H. , Yeh H. I. , Chan W. H.
Published: March 2012

Photoluminescence (PL) from the thiol-capped Au nonoclusters (NCs) has been investigated under site-selective excitation. Upon scanning the excitation light with energy below 2.1 eV down to 1.6 eV, the PL narrows and begins shifting linearly with excitation energy. The time-resolved PL was studied and the PL decay traces of Au NCs were found to depend on the excitation and emission energies. The slow carrier relaxation in the localized states is suggested to be responsible for the line narrowing and peak-shift in the site-selective PL.
Tunnel field-effect transistor heterojunction band alignment by internal photoemission spectroscopy
Authors: Zhang Qin , Zhou Guangle , Xing Huili G. , Seabaugh Alan C. , Xu Kun , Sio Hong , Kirillov Oleg A. , Richter Curt A. , Nguyen N. V.
Published: March 2012

The electron energy band alignment of a metal-oxide-semiconductor tunnel field-effect transistor heterojunction, W/Al2O3/InGaAs/InAs/InP, is determined by internal photoemission spectroscopy. At the oxide flat-band condition, the barrier height from the top of the InGaAs/InAs valence band and the top of the InP valence band to the bottom of the Al2O3 conduction band is determined to be 3.5 and 2.8 eV, respectively. The simulated energy band diagram of the heterostructure is shown to be consistent with the measured band alignments if an equivalent positive charge of 6.0 × 1012 cm−2 is present at the Al2O3/InGaAs. This interface charge is in agreement with previously reported capacitance-voltage measurements.
Considerable asymmetry of the critical current in a niobium thin strip of plano-convex section
Authors: Carapella G. , Sabatino P. , Costabile G.
Published: March 2012

We experimentally demonstrate that in the presence of an in-plane magnetic field the voltage-current curve of a Nb thin strip having plano-convex cross section exhibits considerable asymmetry of the critical current. The observed behavior can be accounted for by the magnetic field component normal to the top convex surface of the strip. Such a component is inhomogeneous, changes sign in the middle of the strip and affects the three-dimensional vortices that in this system have sections locally perpendicular to the top convex surface, though the magnetic field is applied parallel to the bottom flat surface. These sections play the most significant role in the generation of the observed asymmetry. A maximum asymmetry ratio of about 300% at 4.2 K is observed when the strip is in the mixed state and can be ascribed to the balance of the magnetic force due to the inhomogeneous field component and the polarity dependent Lorentz force associated to the transport current.
Time response of Cd0.9Zn0.1Te crystals under transient and pulsed irradiation
Authors: Zhao X. C. , Ouyang X. P. , Xu Y. D. , Han H. T. , Zhang Z. C. , Wang T. , Zha G. Q. , Ouyang X.
Published: March 2012

A CdZnTe detector based on high-quality Cd0.9Zn0.1Te crystals was developed and tested as a monitor in high-intensity radiation fields. The current–voltage measurements were performed using thermally evaporated Au contacts deposited on the crystals, which revealed resistivity of 1010 Ω·cm. Typical leakage current for the planar devices was ∼3 nA for a field strength of 1000 V·cm–1. The test results show that the CdZnTe detector has a fast time response, with a rise time of approximately 2 ns, when exposed to transient and pulsed irradiation of X-rays or electron beams. The decay of current curves is observed and discussed according to charge carrier trapping effects and space-charge accumulation mechanisms. It is suggested that the current decreases quickly with strengthening of the electric field, possibly because of charge de-trapping.
Ambient organic molecular passivation of Si yields near-ideal, Schottky-Mott limited, junctions
Authors: Har-Lavan Rotem , Yaffe Omer , Joshi Pranav , Kazaz Roy , Cohen Hagai , Cahen David
Published: March 2012

We report near-perfect transfer of the electrical properties of oxide-free Si surface, modified by a molecular monolayer, to the interface of a junction made with that modified Si surface. Such behavior is highly unusual for a covalent, narrow bandgap semiconductor, such as Si. Short, ambient atmosphere, room temperature treatment of oxide-free Si(100) in hydroquinone (HQ)/alkyl alcohol solutions, fully passivates the Si surface, while allowing controlled change of the resulting surface potential. The junctions formed, upon contacting such surfaces with Hg, a metal that does not chemically interact with Si, follow the Schottky-Mott model for metal-semiconductor junctions closer than ever for Si-based junctions. Two examples of such ideal behavior are demonstrated: a) Tuning the molecular surface dipole over 400 mV, with only negligible band bending, by changing the alkyl chain length. Because of the excellent passivation this yields junctions with Hg with barrier heights that follow the change in the Si effective electron affinity nearly ideally. b) HQ/ methanol passivation of Si is accompanied by a large surface dipole, which suffices, as interface dipole, to drive the Si into strong inversion as shown experimentally via its photovoltaic effect. With only ∼0.3 nm molecular interlayer between the metal and the Si, our results proves that it is passivation and prevention of metal-semiconductor interactions that allow ideal metal-semiconductor junction behavior, rather than an insulating transport barrier.
The Emotional Effects of Violations of Causality, or How to Make a Square Amusing
Authors: Bressanelli Daniela , Parovel Giulia
Published: March 2012

In Michotte's launching paradigm a square moves up to and makes contact with another square, which then moves off more slowly. In the triggering effect, the second square moves much faster than the first, eliciting an amusing impression. We generated 13 experimental displays in which there was always incongruity between cause and effect. We hypothesized that the comic impression would be stronger when objects are perceived as living agents and weaker when objects are perceived as mechanically non-animated. General findings support our hypothesis.
Blow-up: A Free Lunch?
Authors: Koenderink Jan , Richards Whitman , Van Doorn Andrea
Published: March 2012

We consider operations that change the size of images, either shrinks or blow-ups. Image processing offers numerous possibilities, put at everyone's disposal with such computer programs as Adobe Photoshop. We consider a different class of operations, aimed at immediate visual awareness, rather than pixel arrays. We demonstrate cases of blow-ups that do not sacrifice apparent resolution. This apparent information gain is due to “amodal occlusion.”
Shadows Remain Segmented as Selectable Regions in Object-based Attention Paradigms
Authors: de-Wit Lee , Milner David , Kentridge Robert
Published: March 2012

It is unclear how shadows are processed in the visual system. Whilst shadows are clearly used as an important cue to localise the objects that cast them, there is mixed evidence regarding the extent to which shadows influence the recognition of those objects. Furthermore experiments exploring the perception of shadows per se have provided evidence that the visual system has less efficient access to the detailed form of a region if it is interpreted as a shadow. The current study sought to clarify our understanding of the manner in which shadows are represented by the visual system by exploring how they influence attention in two different object-based attention paradigms. The results provide evidence that cues to interpret a region as a shadow do not reduce the extent to which that region will result in a within-‘object’ processing advantage. Thus, whilst there is evidence that shadows are processed differently at higher stages of object perception, the present result shows that they are still represented as distinctly segmented regions as far as the allocation of attention is concerned. This result is consistent with the idea that object-based attention phenomena result from region-based scene segmentation rather than from the representations of objects per se.
Genomics and the global beef cattle industry
Authors: Pollak E. J. , Bennett G. L. , Snelling W. M. , Thallman R. M. , Kuehn L. A.
Published: March 2012

After two decades of developing DNA-based tools for selection, we are at an interesting juncture. Genomic technology has essentially eliminated the potentially large negative impact of spontaneous single-mutation genetic defects as the management of recent examples in beef cattle have demonstrated. We have the ability to perform more accurate selection based on molecular breeding values (MBVs) for animals closely related to the discovery population. Yet the amount of genetic variation explained falls short of expectations held for the technology. Tests are less effective in distant relatives within a breed and are not robust enough for across-breed use. It is hypothesised that ‘larger single-nucleotide polymorphism (SNP) panels’ will help extend the effective use of tests to more distantly related animals and across breeds. Sequencing and imputing sequences across individuals will enable us to discover causative mutations or SNPs in perfect harmony with the mutation. However, the investment to revisit discovery populations will be large. We can ill afford to duplicate genotyping or sequencing activities for prominent individuals. Hence, a global strategy for genotyping and sequencing becomes an attractive proposition as many of our livestock populations are related. As we learned more of the complexities of the genome, the number of animals in discovery populations necessary to achieve high levels of predictability has grown dramatically. No one organisation has the resources to assemble the animals needed, especially for novel, expensive or hard to measure phenotypes. This scenario is fertile ground for increased international collaboration in all livestock species.
Effects of pre-incubation upside-down positioning of eggs from breeder flocks with different ages on hatchability and chick quality
Authors: Salahi A. , Khabisi M. Moosanezhad , Esmailizadeh A. K.
Published: March 2012

Effects of pre-incubation upside-down positioning of eggs (from collection time at the farm until delivery to the hatchery, which can be up to 5 days) and breeder flock age on hatchability and chick quality were investigated. In this study, 5400 eggs from broiler breeder flocks were assigned to two groups (upside-down and normal position eggs as Control group). The birds were divided in three age groups (46, 73 and 107 weeks of age). Each age group had six replicates with 150 eggs per replicate. The results indicated that keeping eggs in an upside-down position reduced (P < 0.05) hatchability by 4.3% compared with the Control (normal position) group. Also, reversed egg positioning significantly increased relative intestine weight (P < 0.05) and percentage of embryo mortality between 18–19 days of incubation (P < 0.01). Flock age affected (P < 0.01) hatchability, egg shape index, chick cull percentage, infertile eggs, total embryo mortality, percentage egg weight loss and chick yield. The lowest hatchability and the highest percentage egg weight loss were observed in flocks with 107 weeks of age.
Growth dynamics and agronomic-economic benefits of pea - oat and pea - barley intercrops
Authors: Dordas Christos A. , Vlachostergios Dimitrios N. , Lithourgidis Anastasios S.
Published: March 2012

Pea (Pisum arvense L.) is an important legume in many areas of the world, which is used for forage and grain production and could be used in intercropping systems. Intercropping of pea with oat (Avena sativa L.) and barley (Hordeum vulgare L.), in two seeding ratios 60 : 40 and 80 : 20, was compared with pea and two cereal monocrops for two growing seasons (2008–10), at the Aristotle University of Thessaloniki, Greece. The effect of the intercropping systems was determined on growth rate, plant height, chlorophyll content, DM, and N yield. Also, several competition and economic indices were used to evaluate the intercropping systems, such as land equivalent ratio (LER), relative crowding coefficient (K), aggressivity (A), competitive ratio (CR), actual yield loss (AYL), system productivity index (SPI), monetary advantage index (MAI), and intercropping advantage (IA). Growth rate of pea and cereals was lower by an average of 39 and 64%, respectively, in the intercrops than in the monocrops. DM yield was the highest in barley monocrop (13.00 Mg ha–1) followed by P80O20 intercrop (11.73 Mg ha–1). Pea monocrop, and P80O20 and P80B20 intercrops showed the highest crude protein (CP) concentration (137, 132 and 130 g kg–1 DM, respectively), whereas P80O20 intercrop also produced the highest CP yield (1552 kg ha–1). The LER, K, and AYL values (average 1.09, 1.75 and 0.29, respectively), were greater for both pea-oat intercrops compared with the pea-barley intercrops (average 0.98, 0.92 and 0.06, respectively), indicating that in these systems there was an advantage of intercropping for exploiting the resources of the environment. The A, CR, and partial AYL values in all intercrops were greater for oat and barley than pea, which indicated that cereals were more competitive partners than pea. The highest MAI, IA, and SPI values were recorded for P80O20 followed by P60O40 intercrops indicating that these intercropping systems were the most profitable. The results from this study showed that both pea-oat intercrops were more productive with high CP yield, and also they showed the best land-use efficiency.
Effects of drought and high temperature stress on synthetic hexaploid wheat
Authors: Pradhan Gautam P. , Prasad P. V. Vara , Fritz Allan K. , Kirkham Mary B. , Gill Bikram S.
Published: March 2012

Drought and high temperature often occurs simultaneously, causing significant yield losses in wheat (Triticum aestivum L.). The objectives of this study were to: (i) quantify independent and combined effects of drought and high temperature stress on synthetic hexaploid wheat genotypes at anthesis and at 21 days after anthesis; and (ii) determine whether responses to stress varied among genotypes. Four synthetic hexaploid and two spring wheat genotypes were grown from emergence to anthesis (Experiment I) and emergence to 21 days after anthesis (Experiment II), with full irrigation and 21/15°C day/night temperature. Thereafter, four treatments were imposed for 16 days as (a) optimum condition: irrigation + 21/15°C, (b) drought stress: withhold irrigation + 21/15°C, (c) high temperature stress: irrigation + 36/30°C and (d) combined stress: withhold irrigation + 36/30°C. Results indicated a decrease in leaf chlorophyll, individual grain weight and grain yield in an increasing magnitude of drought < high temperature < combined stress. There were 69, 81 and 92% grain yield decreases in Experiment I and 26, 37 and 50% in Experiment II under drought, high temperature and combined stress respectively. Synthetic hexaploid wheat genotypes varied in their response to stresses. Genotypes ALTAR 84/AO’S’ and ALTAR 84/Aegilops tauschii Coss. (WX 193) were least affected by combined stress in Experiments I and II respectively. Overall, combined effect of drought + high temperature stress was more detrimental than the individual stress and the interaction effect was hypo-additive in nature.
Effectiveness of multicultural health workers in chronic disease prevention and self-management in culturally and linguistically diverse populations: a systematic literature review
Authors: Goris Janny , Komaric Nera , Guandalini Amanda , Francis Daniel , Hawes Ellen
Published: March 2012

With a large and increasing culturally and linguistically diverse (CALD) population, the Australian health care system faces challenges in the provision of accessible culturally competent health care. Communities at higher risk of chronic disease include CALD communities. Overseas, multicultural health workers (MHWs) have been increasingly integrated in the delivery of culturally relevant primary health care to CALD communities. The objective of this systematic review was to examine the effectiveness of MHW interventions in chronic disease prevention and self-management in CALD populations with the aim to inform policy development of effective health care in CALD communities in Australia. A systematic review protocol was developed and computerised searches were conducted of multiple electronic databases from 1 January 1995 until 1 November 2010. Thirty-nine studies were identified including 31 randomised controlled trials. Many of the studies focussed on poor and underserved ethnic minorities. Several studies reported significant improvements in participants’ chronic disease prevention and self-management outcomes and meta-analyses identified a positive trend associated with MHW intervention. Australian Government policies express the need for targeted inventions for CALD communities. The broader systemic application of MHWs in Australian primary health care may provide one of the most useful targeted interventions for CALD communities.
Optimising chemical marking techniques for Australian bass, Macquaria novemaculeata, fry and fingerlings prior to restocking
Authors: Cameron Leo M. , Baumgartner Lee J. , Bucher Daniel J. , Robinson Wayne
Published: March 2012

Many stocking programs are performed without any subsequent assessments to determine the survival of the stocked fish, often due to the difficulties in distinguishing stocked from wild fish. A series of optimisation trials were undertaken to determine the suitability of calcein (2,4-bis-[N,N′–di(carbomethyl)-aminomethyl]fluorescein) for chemically marking hatchery-reared Australian bass, Macquaria novemaculeata (Steindachner), fry and fingerlings. The technique was optimised by trialling immersion times for salt (2.5 or 5 min), calcein concentrations (0.5 or 1%) and calcein immersion times (5 or 10 min). A general-purpose modulated probe fluorometer was used as a non-lethal detection method to establish mark retention and distinguish between calcein-marked and unmarked fish. Five minutes of saline immersion, followed by 10 min of calcein immersion at a calcein concentration of 1% was the optimal marking method. Growth and survival of fish was not affected as a result of any of the calcein-marking methods. It is therefore effective to calcein-mark Australian bass fry and fingerlings before stocking and to non-lethally detect marked individuals using a field-portable meter to assist in the assessment of stocking programs. Findings from this study may also reflect the potential use of calcein to chemically mark fry and fingerlings of other fish species.