bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of the dipole bound state on AgF− vibrationally resolved photodetachment cross sections and photoelectron angular distributions
Authors: Dao Diep Bich , Mabbs Richard
Published: October 2014

The first photoelectron spectra of AgF− are recorded over the energy range 1.61–1.85 eV using the velocity map imaging technique. The resolved vibrational structure of the AgF X′, v′ ← AgF− X″, v″ = 0 band yields an AgF electron affinity of 1.46 ± 0.01 eV and vibrational frequency of 500 ± 40 cm−1. For the v′ = 2, 3, 4 channels, the photodetachment cross sections and angular distributions undergo rapid changes over a narrow electron kinetic energy range in the region of 50 meV (approximately 13 meV below the opening of the next vibrational channel). This is consistent with Fano-like behavior indicating autodetachment following excitation to a resonant anion state lying in the detachment continuum. EOM-CCSD calculations reveal this to be a dipole bound state. The consistency of the detachment data with the vibrational autodetachment propensity rule Δv = −1 shows that the autodetachment results from breakdown of the Born-Oppenheimer approximation, coupling the vibrational and electronic degrees of freedom.
Electrodynamic model of the field effect transistor application for THz/subTHz radiation detection: Subthreshold and above threshold operation
Authors: Dobrovolsky V.
Published: October 2014

Developed in this work is an electrodynamic model of field effect transistor (FET) application for THz/subTHz radiation detection. It is based on solution of the Maxwell equations in the gate dielectric, expression for current in the channel, which takes into account both the drift and diffusion current components, and the equation of current continuity. For the regimes under and above threshold at the strong inversion the response voltage, responsivity, wave impedance, power of ohmic loss in the gate and channel have been found, and the electrical noise equivalent power (ENEP) has been estimated. The responsivity is orders of magnitude higher and ENEP under threshold is orders of magnitude less than these values above threshold. Under the threshold, the electromagnetic field in the gate oxide is identical to field of the plane waves in free-space. At the same time, for strong inversion the charging of the gate capacitance through the resistance of channel determines the electric field in oxide.
Frequency control of a new topology in proton exchange membrane fuel cell/wind turbine/photovoltaic/ultra-capacitor/battery energy storage system based isolated networks by a novel intelligent controller
Authors: Taghizadeh Mahdi , Mardaneh Mohammad , Sadeghi Mokhtar Sha
Published: October 2014

This paper proposes a new topology for hybrid isolated networks employing a wind turbine (WT), proton exchange membrane fuel cell (PEMFC), photovoltaic, ultra-capacitor (UC), and battery energy storage system (BESS). The PEMFC is used in parallel with the UC and BESS; a configuration that improves the performance of the PEMFC in terms of dynamic response and lifetime. The proposed topology of the PEMFC along with a new model of WT reduces the initial costs of the hybrid isolated network. Due to power demand fluctuations in isolated networks, to maintain the balance between power generation and consumption, intelligent and flexible control methods must be applied. The variations of the solar irradiance, of the wind speed, and of the power consumption in hybrid isolated networks render the classic controllers and even fuzzy controllers inefficient. To overcome this problem, we use a novel intelligent fuzzy controller which is optimized by the teaching-learning-based optimization method. In the structure of the new proposed controller, the range and place of membership functions are optimized to reduce network frequency oscillations and improve network frequency stability. The designed control methodology is evaluated in the proposed isolated network and its performance is compared with the fuzzy controller, proportional integral (PI) controller, and optimal PI controller. To demonstrate the effectiveness of the proposed control strategies, the above-mentioned detailed mathematical and dynamic models of the isolated network were integrated using MATLAB/Simulink.
Large enhancement of photocatalytic activity by chemical etching of TiO2 crystallized glass
Authors: Yoshida Kazuki , Takahashi Yoshihiro , Ihara Rie , Terakado Nobuaki , Fujiwara Takumi , Kato Hideki , Kakihana Masato
Published: October 2014

The authors aim to report the largest enhancement of photocatalytic activity by chemical etching in anatase-type TiO2 crystallized glass. Optimization of several conditions for crystallization behavior and chemical etching to realize the nano-structured ceramics (NSC) has been performed in the crystallized glass. NSC-fabrication by chemical etching in the crystallized glass is one of the most effective solutions to provide bulk materials with high specific surface area. We have found that the best condition for the NSC fabrication as a novel bulk photocatalyst in our glass system, and have obtained 16 times higher catalytic activity than that of non-etched one.
Tip-induced deformation of a phospholipid bilayer: Theoretical perspective of sum frequency generation imaging
Authors: Volkov Victor
Published: October 2014

The paper addresses theory of Sum Frequency Generation imaging of an atomic force microscopy tip-induced deformation of a bilayer phospholipid membrane deposited over a pore: known as a nano-drum system. Image modeling employed nonlinearities of the normal modes specific to hydrocarbon terminal methyls, which are distributed about the deformed surfaces of inner and outer leaflets. The deformed profiles are according to the solutions of shape equation for Canham-Helfrich Hamiltonian accounting properties of four membranes, which differ in elasticity and adhesion. The results indicate that in continuous deformed surfaces, the difference in the curvature of the outer and inner leaflets dominates in the imaged nonlinearity. This is different comparing to the results for a perfect bilayer spherical cap system (the subject of previous study), where nonlinear image response is dominated by the mismatch of the inner and outer leaflets’ surface areas (as projected to the image plane) at the edge of perfectly spherical structure. The results of theoretical studies, here, demonstrate that Sum Frequency Generation imaging in continuous and deformed bilayer surfaces are helpful to address curvature locally and anticipate mechanical properties of membrane. The articles discuss applicability and practical limitations of the approach. Combination of Atomic Force Microscopy and Sum Frequency Generation imaging under controlled tip-induced deformation provides a good opportunity to probe and test membranes physical properties with rigor of adopted theory.
Photoconductivities in anatase TiO2 nanorods
Authors: Chen Ruei-San , Liu Yi-Ling , Chan Ching-Hsiang , Huang Ying-Sheng
Published: October 2014

The photoconduction (PC) properties of single-crystalline titanium dioxide (TiO2) nanorods (NRs) with anatase phase were investigated and compared. By examining the material's inherent properties, the anatase TiO2 NRs exhibit superior PC efficiency (quantitatively defined by normalized gain) which is near one order of magnitude higher than that of the rutile ones. The optimal photoconductive gain of the anatase NR device can also reach 1.6 × 107 at the light intensity of 0.02 Wm−2 and a low bias of 0.1 V. The power-dependent and time-resolved PC measurements were performed to investigate the physical mechanisms. The higher quantum efficiency and mobility product was confirmed to be responsible for the higher PC efficiency in the anatase TiO2 NRs in comparison to the rutile ones.
The equipment for the preparation of micro and nanoscale metallic glassy fibers
Authors: Ding D. W. , Yi J. , Liu G. L. , Sun Y. T. , Zhao D. Q. , Pan M. X. , Bai H. Y. , Wang W. H.
Published: October 2014

A supercooled liquid extraction method and apparatus for micro and nanoscale metallic glassy fiber preparation was developed. Using the fiber fabrication equipment, micro to nanoscale metallic glassy fibers with diameter ranging from 70 nm to 300 μm can be obtained by wire drawing in the supercooled liquid region of metallic glasses via superplastic deformation. The obtained metallic glassy fibers possess precisely designed and controlled sizes, high structural uniformity and high degree of surface smoothness.
Design of a spin-wave majority gate employing mode selection
Authors: Klingler S. , Pirro P. , Brächer T. , Leven B. , Hillebrands B. , Chumak A. V.
Published: October 2014

The design of a microstructured, fully functional spin-wave majority gate is presented and studied using micromagnetic simulations. This all-magnon logic gate consists of three-input waveguides, a spin-wave combiner, and an output waveguide. In order to ensure the functionality of the device, the output waveguide is designed to perform spin-wave mode selection. We demonstrate that the gate evaluates the majority of the input signals coded into the spin-wave phase. Moreover, the all-magnon data processing device is used to perform logic AND-, OR-, NAND-, and NOR- operations.
Quantitative electron density characterization of soft tissue substitute plastic materials using grating-based x-ray phase-contrast imaging
Authors: Sarapata A. , Chabior M. , Cozzini C. , Sperl J. I. , Bequé D. , Langner O. , Coman J. , Zanette I. , Ruiz-Yaniz M. , Pfeiffer F.
Published: October 2014

Many scientific research areas rely on accurate electron density characterization of various materials. For instance in X-ray optics and radiation therapy, there is a need for a fast and reliable technique to quantitatively characterize samples for electron density. We present how a precise measurement of electron density can be performed using an X-ray phase-contrast grating interferometer in a radiographic mode of a homogenous sample in a controlled geometry. A batch of various plastic materials was characterized quantitatively and compared with calculated results. We found that the measured electron densities closely match theoretical values. The technique yields comparable results between a monochromatic and a polychromatic X-ray source. Measured electron densities can be further used to design dedicated X-ray phase contrast phantoms and the additional information on small angle scattering should be taken into account in order to exclude unsuitable materials.
Laser plasma formation assisted by ultraviolet pre-ionization
Authors: Yalin Azer P. , Wilvert Nick , Dumitrache Ciprian , Joshi Sachin , Shneider Mikhail N.
Published: October 2014

We present experimental and modeling studies of air pre-ionization using ultraviolet (UV) laser pulses and its effect on laser breakdown of an overlapped near-infrared (NIR) pulse. Experimental studies are conducted with a 266 nm beam (fourth harmonic of Nd:YAG) for UV pre-ionization and an overlapped 1064 nm NIR beam (fundamental of Nd:YAG), both having pulse duration of ∼10 ns. Results show that the UV beam produces a pre-ionized volume which assists in breakdown of the NIR beam, leading to reduction in NIR breakdown threshold by factor of >2. Numerical modeling is performed to examine the ionization and breakdown of both beams. The modeled breakdown threshold of the NIR, including assist by pre-ionization, is in reasonable agreement with the experimental results.
Phonon scattering in graphene over substrate steps
Authors: Sevinçli H. , Brandbyge M.
Published: October 2014

We calculate the effect on phonon transport of substrate-induced bends in graphene. We consider bending induced by an abrupt kink in the substrate, and provide results for different step-heights and substrate interaction strengths. We find that individual substrate steps reduce thermal conductance in the range between 5% and 47%. We also consider the transmission across linear kinks formed by adsorption of atomic hydrogen at the bends and find that individual kinks suppress thermal conduction substantially, especially at high temperatures. Our analysis show that substrate irregularities can be detrimental for thermal conduction even for small step heights.
Electromagnetic properties of Permendur granular composite materials containing flaky particles
Authors: Kasagi Teruhiro , Tsutaoka Takanori , Hatakeyama Kenichi
Published: October 2014

Electromagnetic properties of Permendur (Fe50Co50 alloy) granular composite materials containing flaky particle have been studied from the RF to microwave frequency range. Properties of the flaky particle composites were compared with the spherical particle ones. The electrical conductivity of the flaky particle composite was higher than that of the spherical particle composite at the same particle content. An insulator to metal transition was observed at the percolation threshold φc in both composites. The φc of the flaky particle composite was lower than that of the spherical one. The relative complex permittivity indicates that the insulating state has dielectric properties. For the spherical particle composite, the permittivity enhancement caused by particle cluster formation can be described by the effective cluster model (ECM). The enhancement of the dielectric constant in the flaky particle composite is larger than the ECM prediction. A negative permittivity spectrum indicating a low frequency plasmonic state was observed in the metallic 70 vol. % flaky particle composite. The relative complex permeability spectra of the flaky particle composite are different from those of the spherical one. The flaky particle composite shows a larger permeability value and lower permeability dispersion frequency than the spherical particle composite. Negative permeability spectra were observed in the both composite materials. The negative permeability frequency band of the flaky particle composite is lower than that of the spherical particle composite owing to the demagnetizing field effect.
Atomic scale insight into the amorphous structure of Cu doped GeTe phase-change material
Authors: Zhang Linchuan , Sa Baisheng , Zhou Jian , Song Zhitang , Sun Zhimei
Published: October 2014

GeTe shows promising application as a recording material for phase-change nonvolatile memory due to its fast crystallization speed and extraordinary amorphous stability. To further improve the performance of GeTe, various transition metals, such as copper, have been doped in GeTe in recent works. However, the effect of the doped transition metals on the stability of amorphous GeTe is not known. Here, we shed light on this problem for the system of Cu doped GeTe by means of ab initio molecular dynamics calculations. Our results show that the doped Cu atoms tend to agglomerate in amorphous GeTe. Further, base on analyzing the pair correlation functions, coordination numbers and bond angle distributions, remarkable changes in the local structure of amorphous GeTe induced by Cu are obviously seen. The present work may provide some clues for understanding the effect of early transition metals on the local structure of amorphous phase-change compounds, and hence should be helpful for optimizing the structure and performance of phase-change materials by doping transition metals.
Comment on “The dependence of homogeneous nucleation rate on supersaturation” [J. Chem. Phys. 141, 024307 (2014)]
Authors: Hansen K.
Published: October 2014

The role of deviations of cluster binding energies from liquid drop values as extrapolated from bulk values is discussed, with reference to conclusions reached in a recent publication [S. L. Girshick, J. Chem. Phys. 141, 024307 (2014)].
Terahertz magnetic modulator based on magnetically clustered nanoparticles
Authors: Shalaby Mostafa , Peccianti Marco , Ozturk Yavuz , Al-Naib Ibraheem , Hauri Christoph P. , Morandotti Roberto
Published: October 2014

Random orientation of liquid-suspended magnetic nanoparticles (Ferrofluids) gives rise to a zero net magnetic orientation. An external magnetic field tends to align these nanoparticles into clusters, leading to a strong linear dichroism on a propagating wave. Using 10 nm-sized Fe3O4, we experimentally realize a polarization-sensitive magnetic modulator operating at terahertz wavelengths. We reached a modulation depth of 66% using a field as low as 35 mT. The proposed concept offers a solution towards fundamental terahertz magnetic modulators.
Shock wave generated by high-energy electric spark discharge
Authors: Liu Qingming , Zhang Yunming
Published: October 2014

Shock wave generated by electric spark discharge was studied experimentally and the shock wave energy was evaluated in this paper. A pressure measurement system was established to study the pressure field of the electric spark discharge process. A series of electric spark discharge experiments were carried out and the energy of the electric spark used in present study was in the range of 10 J, 100 J, and 1000 J, respectively. The shock wave energy released from the electric spark discharge process was calculated by using the overpressure values at different measurement points near the electric spark discharge center. The good consistency of shock wave energies calculated by pressure histories at different measuring points in the same electric spark discharge experiment illustrates the applicability of the weak shock wave theory in calculating the energy of shock wave induced by electric spark discharge process. The result showed that shock wave formed at the initial stage of electric spark discharge process, and the shock wave energy is only a little part of electric spark energy. From the analysis of the shock wave energy and electric spark energy, a good linear relationship between shock wave energy and electric spark energy was established, which make it possible to calculate shock wave energy by measuring characteristic parameters of electric spark discharge process instead of shock wave. So, the initiation energy of direct initiation of detonation can be determined easily by measuring the parameters of electric spark discharge process.
Toroidal current asymmetry in tokamak disruptions
Authors: Strauss H. R.
Published: October 2014

It was discovered on JET that disruptions were accompanied by toroidal asymmetry of the toroidal plasma current Iϕ. It was found that the toroidal current asymmetry was proportional to the vertical current moment asymmetry with positive sign for an upward vertical displacement event (VDE) and negative sign for a downward VDE. It was observed that greater displacement leads to greater measured Iϕ asymmetry. Here, it is shown that this is essentially a kinematic effect produced by a VDE interacting with three dimensional MHD perturbations. The relation of toroidal current asymmetry and vertical current moment is calculated analytically and is verified by numerical simulations. It is shown analytically that the toroidal variation of the toroidal plasma current is accompanied by an equal and opposite variation of the toroidal current flowing in a thin wall surrounding the plasma. These currents are connected by 3D halo current, which is π/2 radians out of phase with the n = 1 toroidal current variations.
Molecularly imprinted electrochemical sensing of urinary melatonin in a microfluidic system
Authors: Lee Mei-Hwa , O'Hare Danny , Chen Yi-Li , Chang Yu-Chia , Yang Chien-Hsin , Liu Bin-Da , Lin Hung-Yin
Published: October 2014

Melatonin levels may be related to the risks of breast cancer and prostate cancer. The measurement of urinary melatonin is also useful in monitoring serum melatonin levels following oral administration. In this work, melatonin is the target molecule, which is imprinted onto poly(ethylene-co-vinyl alcohol) by evaporation of the solvent on the working electrode of an electrochemical sensing chip. This sensing chip is used directly as a tool for optimizing the imprinting polymer composition, flow rate, and injection volume of the samples. Microfluidic sensing of the target and interference molecules revealed that the lowest detection limit is as low as ∼pM, and the electrochemical response is weak even at high interference concentrations. Poly(ethylene-co-vinyl alcohol), containing 44 mol. % ethylene, had an imprinting effectiveness of more than six-fold. In random urine analysis, the microfluidic amperometric measurements of melatonin levels with an additional and recovery of melatonin, the melatonin recovery achieved 94.78 ± 1.9% for melatonin at a concentration of 1.75–2.11 pg/mL.
Note: A charge sensitive spectroscopy amplifier for position sensitive micro-channel plate detectors
Authors: Wang Wei , Yu Deyang , Liu Junliang , Lu Rongchun , Cai Xiaohong
Published: October 2014

A compact and low noise charge sensitive spectroscopy amplifier which can be integrated into position sensitive micro-channel plate (MCP) detectors has been constructed. The amplifier was optimized by using a wave form generator and tested by a chevron shape MCP detector. The output noise of 4 mVrms was achieved while the gain is 1012 V/C and the shaping time is 700 ns.
Short-pulse CO2 laser with longitudinal tandem discharge tube
Authors: Uno K. , Akitsu T. , Jitsuno T.
Published: October 2014

We developed a longitudinally excited CO2 laser with a tandem discharge tube. The tandem scheme was constituted of two 30-cm long discharge tubes connected with an intermediate electrode. Two parts, each consisting of a charged capacitance and a 30-cm long discharge tube, were electrically connected in parallel and switched by a spark gap. The tandem scheme produced a short laser pulse like that of a TEA-CO2 laser with a charging voltage of −24.8 kV, which was smaller than the −40.0 kV charging voltage of our previous CO2 laser. At a gas pressure of 3.8 kPa, the spike pulse width was 145 ns, the pulse tail length was 58.8 μs, the output energy was 52.0 mJ, and the spike pulse energy was 2.4 mJ. We also investigated the dependence of the laser pulse and the discharge voltage on gas pressure.
An on-chip study on the influence of geometrical confinement and chemical gradient on cell polarity
Authors: Zheng Wenfu , Xie Yunyan , Sun Kang , Wang Dong , Zhang Yi , Wang Chen , Chen Yong , Jiang Xingyu
Published: October 2014

Cell polarity plays key roles in tissue development, regeneration, and pathological processes. However, how the cells establish and maintain polarity is still obscure so far. In this study, by employing microfluidic techniques, we explored the influence of geometrical confinement and chemical stimulation on the cell polarity and their interplay. We found that teardrop shape-induced anterior/posterior polarization of cells displayed homogeneous distribution of epidermal growth factor receptor, and the polarity could be maintained in a uniform epidermal growth factor (EGF) solution, but be broken by a reverse gradient of EGF, implying different mechanism of geometrical and chemical cue-induced cell polarity. Further studies indicated that a teardrop pattern could cause polarized distribution of microtubule-organization center and nucleus-Golgi complex, and this polarity was weakened when the cells were released from the confinement. Our study provides the evidence regarding the difference between geometrical and chemical cue-induced cell polarity and would be useful for understanding relationship between polarity and directional migration of cells.
Influence of post-deposition annealing on interfacial properties between GaN and ZrO2 grown by atomic layer deposition
Authors: Ye Gang , Wang Hong , Geok Ng Serene Lay , Ji Rong , Arulkumaran Subramaniam , Ng Geok Ing , Li Yang , Liu Zhi Hong , Ang Kian Siong
Published: October 2014

Influence of post-deposition annealing on interfacial properties related to the formation/annihilation of interfacial GaOx layer of ZrO2 grown by atomic layer deposition (ALD) on GaN is studied. ZrO2 films were annealed in N2 atmospheres in temperature range of 300 °C to 700 °C and analyzed by X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. It has been found that Ga-O bond to Ga-N bond area ratio decreases in the samples annealed at temperatures lower than 500 °C, which could be attributed to the thinning of GaOx layer associated with low surface defect states due to “clean up” effect of ALD-ZrO2 on GaN. However, further increase in annealing temperature results in deterioration of interface quality, which is evidenced by increase in Ga-O bond to Ga-N bond area ratio and the reduction of Ga-N binding energy.
Voltage-controlled inversion of tunnel magnetoresistance in epitaxial nickel/graphene/MgO/cobalt junctions
Authors: Godel F. , Venkata Kamalakar M. , Doudin B. , Henry Y. , Halley D. , Dayen J.-F.
Published: October 2014

We report on the fabrication and characterization of vertical spin-valve structures using a thick epitaxial MgO barrier as spacer layer and a graphene-passivated Ni film as bottom ferromagnetic electrode. The devices show robust and scalable tunnel magnetoresistance, with several changes of sign upon varying the applied bias voltage. These findings are explained by a model of phonon-assisted transport mechanisms that relies on the peculiarity of the band structure and spin density of states at the hybrid graphene|Ni interface.
Direct-bandgap GeSn grown on silicon with 2230 nm photoluminescence
Authors: Ghetmiri Seyed Amir , Du Wei , Margetis Joe , Mosleh Aboozar , Cousar Larry , Conley Benjamin R. , Domulevicz Lucas , Nazzal Amjad , Sun Greg , Soref Richard A. , Tolle John , Li Baohua , Naseem Hameed A. , Yu Shui-Qing
Published: October 2014

Material and optical characterizations have been conducted for epitaxially grown Ge1−xSnx thin films on Si with Sn composition up to 10%. A direct bandgap Ge0.9Sn0.1 alloy has been identified by temperature-dependent photoluminescence (PL) study based on the single peak spectrum and the narrow line-width. Room temperature PL emission as long as 2230 nm has also been observed from the same sample.
Advances in three-dimensional rapid prototyping of microfluidic devices for biological applications
Authors: O'Neill P. F. , Ben Azouz A. , Vázquez M. , Liu J. , Marczak S. , Slouka Z. , Chang H. C. , Diamond D. , Brabazon D.
Published: October 2014

The capability of 3D printing technologies for direct production of complex 3D structures in a single step has recently attracted an ever increasing interest within the field of microfluidics. Recently, ultrafast lasers have also allowed developing new methods for production of internal microfluidic channels within the bulk of glass and polymer materials by direct internal 3D laser writing. This review critically summarizes the latest advances in the production of microfluidic 3D structures by using 3D printing technologies and direct internal 3D laser writing fabrication methods. Current applications of these rapid prototyped microfluidic platforms in biology will be also discussed. These include imaging of cells and living organisms, electrochemical detection of viruses and neurotransmitters, and studies in drug transport and induced-release of adenosine triphosphate from erythrocytes.
Improving the binding efficiency of quartz crystal microbalance biosensors by applying the electrothermal effect
Authors: Huang Yao-Hung , Chang Jeng-Shian , Chao Sheng D. , Wu Kuang-Chong , Huang Long-Sun
Published: October 2014

A quartz crystal microbalance (QCM) serving as a biosensor to detect the target biomolecules (analytes) often suffers from the time consuming process, especially in the case of diffusion-limited reaction. In this experimental work, we modify the reaction chamber of a conventional QCM by integrating into the multi-microelectrodes to produce electrothermal vortex flow which can efficiently drive the analytes moving toward the sensor surface, where the analytes were captured by the immobilized ligands. The microelectrodes are placed on the top surface of the chamber opposite to the sensor, which is located on the bottom of the chamber. Besides, the height of reaction chamber is reduced to assure that the suspended analytes in the fluid can be effectively drived to the sensor surface by induced electrothermal vortex flow, and also the sample costs are saved. A series of frequency shift measurements associated with the adding mass due to the specific binding of the analytes in the fluid flow and the immobilized ligands on the QCM sensor surface are performed with or without applying electrothermal effect (ETE). The experimental results show that electrothermal vortex flow does effectively accelerate the specific binding and make the frequency shift measurement more sensible. In addition, the images of the binding surfaces of the sensors with or without applying electrothermal effect are taken through the scanning electron microscopy. By comparing the images, it also clearly indicates that ETE does raise the specific binding of the analytes and ligands and efficiently improves the performance of the QCM sensor.
Ultraviolet Raman spectra of few nanometer thick silicon-on-insulator nanofilms: Lifetime reduction of confined phonons
Authors: Poborchii Vladimir , Morita Yukinori , Ishimaru Manabu , Tada Tetsuya
Published: October 2014

We show that in Si-on-insulator (SOI) nanofilms (NFs), phonon-confinement-induced longitudinal optical (LO) phonon Raman band asymmetric broadening is much weaker than thickness-inversely-proportional symmetric broadening associated with phonon lifetime reduction. We discuss the origin of the effect, determine LO phonon lifetime in SOI NFs and modify Richter-Campbell-Fauchet model describing the confined-phonon Raman band shape by taking the symmetric broadening into account. We also discuss connection of the effect with SOI NF thermal conductivity reduction.
Ambipolar quantum dots in intrinsic silicon
Authors: Betz A. C. , Gonzalez-Zalba M. F. , Podd G. , Ferguson A. J.
Published: October 2014

We electrically measure intrinsic silicon quantum dots with electrostatically defined tunnel barriers. The presence of both p- and n-type ohmic contacts enables the accumulation of either electrons or holes. Thus, we are able to study both transport regimes within the same device. We investigate the effect of the tunnel barriers and the electrostatically defined quantum dots. There is greater localisation of charge states under the tunnel barriers in the case of hole conduction, leading to higher charge noise in the p-type regime.
Effects of inductive waves on multi-band below-cut-off transmission in waveguides loaded with dielectric metamaterials
Authors: Chen Fang , Wang Xiaohui , Semouchkin George , Semouchkina Elena
Published: October 2014

Unusual backward and forward wave propagation in below cut-off waveguides loaded with dielectric metamaterials comprised of linear arrays of dielectric resonators (DRs) has been investigated by using theoretical, numerical, and experimental methods. Transmission bands were shown to correspond to three lowest resonances in arrays and were analyzed by using the concepts of magneto- and electro-inductive (MI and EI) waves describing the transfer of resonance excitation along the chains of coupled resonators. Equivalent circuit models (ECMs) have been constructed to describe MI and EI wave propagation and to obtain the dispersion diagrams. Good agreement between the obtained data and the results of full-wave simulations, theoretical calculations, and experiments provided an opportunity to determine coupling coefficients characterizing interaction between DRs in arrays at various resonances. It was shown that ripples observed in below cut-off transmission bands are transmission resonances caused by Fabry-Perot oscillations of inductive waves at impedance mismatch at the array ends. Fitting the transmission spectra for MI/EI waves in arrays, calculated by using the Transfer Matrix Method to the spectra obtained by using full-wave simulations/measurements, allowed for determining the ECM parameters to fully characterize the DR array properties.
Self-consistent fluid modeling and simulation on a pulsed microwave atmospheric-pressure argon plasma jet
Authors: Chen Zhaoquan , Yin Zhixiang , Chen Minggong , Hong Lingli , Xia Guangqing , Hu Yelin , Huang Yourui , Liu Minghai , Kudryavtsev A. A.
Published: October 2014

In present study, a pulsed lower-power microwave-driven atmospheric-pressure argon plasma jet has been introduced with the type of coaxial transmission line resonator. The plasma jet plume is with room air temperature, even can be directly touched by human body without any hot harm. In order to study ionization process of the proposed plasma jet, a self-consistent hybrid fluid model is constructed in which Maxwell's equations are solved numerically by finite-difference time-domain method and a fluid model is used to study the characteristics of argon plasma evolution. With a Guass type input power function, the spatio-temporal distributions of the electron density, the electron temperature, the electric field, and the absorbed power density have been simulated, respectively. The simulation results suggest that the peak values of the electron temperature and the electric field are synchronous with the input pulsed microwave power but the maximum quantities of the electron density and the absorbed power density are lagged to the microwave power excitation. In addition, the pulsed plasma jet excited by the local enhanced electric field of surface plasmon polaritons should be the discharge mechanism of the proposed plasma jet.
Spatial distribution of the electrical potential and ion concentration in the downstream area of atmospheric pressure remote plasma
Authors: Mishin M. V. , Protopopova V. S. , Uvarov A. A. , Alexandrov S. E.
Published: October 2014

This paper presents the results from an experimental study of the ion flux characteristics behind the remote plasma zone in a vertical tube reaction chamber for atmospheric pressure plasma enhanced chemical vapor deposition. Capacitively coupled radio frequency plasma was generated in pure He and gas mixtures: He–Ar, He–O2, He–TEOS. We previously used the reaction system He–TEOS for the synthesis of self-assembled structures of silicon dioxide nanoparticles. It is likely that the electrical parameters of the area, where nanoparticles have been transported from the synthesis zone to the substrate, play a significant role in the self-organization processes both in the vapor phase and on the substrate surface. The results from the spatial distribution of the electrical potential and ion concentration in the discharge downstream area measured by means of the external probe of original design and the special data processing method are demonstrated in this work. Positive and negatives ions with maximum concentrations of 106–107 cm−3 have been found at 10–80 mm distance behind the plasma zone. On the basis of the revealed distributions for different gas mixtures, the physical model of the observed phenomena is proposed. The model illustrates the capability of the virtual ion emitter formation behind the discharge gap and the presence of an extremum of the electrical potential at the distance of approximately 10−2–10−1 mm from the grounded electrode.
Irreversibility of the martensitic transformation in Ni-Mn-In single crystal studied by resistivity under pressure and in situ optical observations
Authors: Porcar L. , Courtois P. , Crouigneau G. , Debray J. , Bourgault D.
Published: October 2014

Optical observations under uniaxial pressure and in-situ resistivity measurements were undertaken in Ni-Mn-In single crystals as a function of temperature to study the thermal hysteresis of the martensitic transformation. The irreversibility of the isothermal transformation under pressure was clearly observed, and it was possible to stabilize the martensitic phase with large and coarsen variants by applying a pressure at a stable temperature Ms reached during cooling down (cooling branch of the hysteresis). When the uniaxial pressure is applied in the heating branch of the hysteresis, the martensitic transformation occurs in a complete reversible way as the hysteresis delimitates the metastability of the martensitic/austenitic phases and the energy barrier to overcome for the transformation. This procedure leads to a piezoresistance as large as 200%.
Two Sensory Channels Mediate Perception of Fingertip Force
Authors: Brothers Trevor , Hollins Mark
Published: October 2014

In two experiments we examined the ability of humans to exert forces accurately with the fingertips, and to perceive those forces. In experiment 1 participants used visual feedback to apply a range of fingertip forces with the distal pad of the thumb. Participants made magnitude discriminations regarding these forces, and their just noticeable differences were calculated at a series of standards by means of a two-interval, forced-choice tracking paradigm. As the standard increased, participants demonstrated a relative improvement in force discrimination; and the presence of a possible inflection point, at approximately 400 g, suggested that two sensory channels may contribute to performance. If this is the case, the operative channel at low forces is almost certainly the slowly adapting type I (SA-I) channel, while another mechanoreceptor class, the SA-II nail unit, is a plausible mediator of the more accurate performance seen at high force levels. To test this two-channel hypothesis in experiment 2, we hydrated participants' thumbnails in order to reduce nail rigidity and thus prevent stimulation of underlying SA-II mechanoreceptors. This technique was found to reduce sensory accuracy in a force-matching task at high forces (1000 g) while leaving low force matching (100 g) unimpaired. Taken together, these results suggest that two sensory channels mediate the perception of fingertip forces in humans: One channel predominating at low forces (below approximately 400 g) and another responsible for perceiving high forces which is likely mediated by the SA-II nail unit.
An Observational, Laboratory-Based Study of Outbreaks of Middle East Respiratory Syndrome Coronavirus in Jeddah and Riyadh, Kingdom of Saudi Arabia, 2014
Authors: Drosten Christian , Muth Doreen , Corman Victor M. , Hussain Raheela , Al Masri Malaki , HajOmar Waleed , Landt Olfert , Assiri Abdullah , Eckerle Isabella , Al Shangiti Ali , Al-Tawfiq Jaffar A. , Albarrak Ali , Zumla Alimuddin , Rambaut Andrew , Memish Ziad A.
Published: October 2014

Background.  In spring 2014, a sudden rise in the number of notified Middle East respiratory syndrome coronavirus (MERS-CoV) infections occurred across Saudi Arabia with a focus in Jeddah. Hypotheses to explain the outbreak pattern include increased surveillance, increased zoonotic transmission, nosocomial transmission, and changes in viral transmissibility, as well as diagnostic laboratory artifacts.

Methods.  Diagnostic results from Jeddah Regional Laboratory were analyzed. Viruses from the Jeddah outbreak and viruses occurring during the same time in Riyadh, Al-Kharj, and Madinah were fully or partially sequenced. A set of 4 single-nucleotide polymorphisms distinctive to the Jeddah outbreak were determined from additional viruses. Viruses from Riyadh and Jeddah were isolated and studied in cell culture.

Results.  Up to 481 samples were received per day for reverse transcription polymerase chain reaction (RT-PCR) testing. A laboratory proficiency assessment suggested positive and negative results to be reliable. Forty-nine percent of 168 positive-testing samples during the Jeddah outbreak stemmed from King Fahd Hospital. All viruses from Jeddah were monophyletic and similar, whereas viruses from Riyadh were paraphyletic and diverse. A hospital-associated transmission cluster, to which cases in Indiana (United States) and the Netherlands belonged, was discovered in Riyadh. One Jeddah-type virus was found in Riyadh, with matching travel history to Jeddah. Virus isolates representing outbreaks in Jeddah and Riyadh were not different from MERS-CoV EMC/2012 in replication, escape of interferon response, or serum neutralization.

Conclusions.  Virus shedding and virus functions did not change significantly during the outbreak in Jeddah. These results suggest the outbreaks to have been caused by biologically unchanged viruses in connection with nosocomial transmission.
Ponte Osteotomy During Dekyphosis for Indirect Posterior Decompression With Ossification of the Posterior Longitudinal Ligament of the Thoracic Spine
Authors: Ando Kei , Imagama Shiro , Ito Zenya , Kobayashi Kazuyoshi , Ukai Junichi , Muramoto Akio , Shinjo Ryuichi , Matsumoto Tomohiro , Nakashima Hiroaki , Matsuyama Yukihiro , Ishiguro Naoki
Published: October 2014

Study Design:

Retrospective clinical study.

Purpose:

To investigate the outcomes after indirect posterior decompression and dekyphosis using multilevel Ponte osteotomies for ossification of the posterior longitudinal ligament (OPLL) of the thoracic spine.

Summary of Background Data:

There are no previous reports on the use of Ponte osteotomy to treat thoracic OPLL.

Methods:

The subjects were 10 patients with an average age at surgery of 47 years, who underwent indirect posterior decompression and dekyphosis using multilevel Ponte osteotomies at our institute. Minimum follow-up period was 2 years, and averaged 2 year 6 months. Using radiographs and CT images, we investigated fusion range, preoperative and postoperative Cobb angles of thoracic fusion levels, intraoperative ultrasonography, and clinical results.

Results:

The mean fusion area was 9.8 vertebraes, with average laminectomy of 7.3 laminas. The mean preoperative thoracic kyphosis of fusion levels on standing radiograph measured 35 degrees and was changed to 21 degrees after surgery. The mean number of Ponte osteotomies was 3 levels. The mean preoperative and postoperative (at the 1 y follow-up) JOA scores were 3.5 and 7.5 points, respectively, and the recovery rate was 56%. On intraoperative ultrasonography, 7 of the cases were included in the floating (+) and 3 in the floating (−) groups, and the recovery rates were 66.0% and 33.4%, respectively.

Conclusions:

“The Ponte procedure for indirect spinal cord decompression” is a novel concept used for the first time with thoracic OPLL in our study, and we consider it a useful method to achieve more effectively dekyphosis and indirect spinal cord decompression if there is not the spinal cord free from OPLL on intraoperative ultrasonography after only laminectomies.
Effect of pre-and post-harvest treatments on the fruit quality and the occurrence of fruit skin stain during the storage of 'Niitaka' pears
Authors: Moon Byung-Woo , Yoon Deok-Hoon , Nam Ki-Woong
Published: October 2014

The effect of pre-storage treatments was investigated to control the occurrence of fruit skin stain in 'Niitaka' pears. The incidence of fruit skin stains was significantly reduced when the fruits were stored in paper bags with a yellow inner color, compared to when they were stored in paper bags with blue and red inner colors. Additionally, the pear fruits that were harvested seven days earlier than their optimum maturity date developed less fruit skin stains in cold storage and retained their quality. Storage in polyethylene (PE) bags did not control the occurrence of fruit skin stains as effectively as did bag-free storage or storage in calcium-coated bags. The dipping of the pear fruits in a chlorine dioxide and calcium solution was highly effective in reducing the fruit skin stains compared to when they were not dipped or when they were dipped only in distilled water. In particular, a 1,500 times diluted solution of sodium dichloroisocyannurate (NaDCC) reduced the incidence of fruit skin stains and the size of the lesions. No stain was observed on the skin of the fruit with a water content lower than 67.7% (w/v) during its storage. In conclusion, packaging pear fruits in bags with an inner calcium coat and dipping them in a chlorine dioxide, calcium, or NaDCC solution can effectively reduce their skin stains during their storage.
Effects of mulberry concentrate on lipid oxidation of Yackwa during its storage
Authors: Shin Suk-Kyung , Kim Hyun-Jeong , Kim Mee-Ree
Published: October 2014

This study was conducted to evaluate the quality and to inhibit the lipid oxidation of Yackwa with 0, 1, 2, or 3% mulberry concentrate added. We stored Yackwa at 60°C for three weeks. After the three-week storage, the acid value of the Yackwa with mulberry concentrate was lower than that of the control Yackwa. The hydroperoxide value (22.39 meq/kg) of the Yackwa with 3% mulberry concentrate at two weeks of storage was 50% lower than that of the control Yackwa (47.03 meq/kg). Also, after three-week storage, the TBA value of the Yackwa with 3% mulberry concentrate was about two times lower than that of the control group. The L and b values in the Hunter color system of the Yackwa with mulberry concentrate decreased significantly as the amount of the mulberry added increased, whereas the a value increased. The antioxidant activity, such as the DPPH radical scavenging activity, significantly increased in the Yackwa with mulberry concentrate, unlike in the control. These results might have been caused by the mulberry concentrate, which contains an antioxidant. The ability of the mulberry concentrate to delay the rancidity of the Yackwa was due to its antioxidant activity.
Physicochemical and sensory characteristics of Samgyetang retorted at different F0 values during storage at room temperature
Authors: Lee Jin Hwan , Lee Jin Ho , Lee Keun Taik
Published: October 2014

Changes in various physicochemical and sensory characteristics of Samgyetang retorted at the F0 values of 4.0 (F4), 7.0 (F7), and 10.0 (F10) were investigated during storage at 25°C for 12 months. The pH level tended to decrease in all the treatments with the increase of the storage time, but no significant difference in the extent of the decrease was observed among the treatments. The values of volatile basic nitrogen, thiobarbituric reactive substances, and carbonyl contents increased rapidly over the storage period in the order of F4 > F7 > F10. The viscosity decreased most sharply between month 0 and month 2, after which the rate of increase declined. The oxygen concentration in the headspace of the retort pouch of the Samgyetang was higher for the samples retorted at higher F0 values. In the sensory tests, the scores of the samples retorted at higher F0 values tended to be lower, but all the characteristics of the samples, except for the texture of the T10 samples, were evaluated with scores higher than 5.0, the limit of marketability, over the storage time. In conclusion, the quality of the Samgyetang samples treated at higher F0 values deteriorated more noticeably during storage.
A study of the levels of natural preservatives in wild plants
Authors: Baek Kyoung-A , Kang Heun-Kag , Shin Myoung-Hee , Park Jong-Jin , Kim Jong-Dae , Park Seong-Min , Lee Mi-Young , Im Ji-Soon
Published: October 2014

To examine the levels of preservatives that occur naturally in food, wild plants used as commercial teas, rice cakes, or spices were studied according to the method of the Korean Food Code and analyzed with a gas chromatograph and HPLC. The levels of the natural preservatives (sodium dehydroacetate, sorbic acid, benzoic acid, methyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, isopropyl p-hydroxybenzoate, propyl p-hydroxybenzoate, isobutyl p-hydroxybenzoate, butyl p-hydroxybenzoate, and propionic acid) in 21 cases were investigated against 15 kinds of wild plants. Six of 15 kinds of wild plants, such as pine needles, bamboo leaf, kudzu leaf, ramie leaf, mugwort, and nut pine leaf, were confirmed to have had sorbic acid, benzoic acid, and propionic acid. 8.201-21.839 mg/kg of benzoic acid was detected in the bamboo leaf, ramie leaf, pine needles, mugwort, kudzu leaf, and nut pine leaf. The sorbic acid contents of the bamboo leaf and the kudzu leaf were 5.630-24.995 mg/kg, respectively. The propionic acid content of the ramie leaf was 61.324-62.726 mg/kg. Nine kinds of wild plants, such as the Korean berchimia leaf, taro leaf, sasa borealis, lotus leaf, kuansh, chrysanthemum zawadskii, oak tree leaf, Chinese pepper leaf, and persimmon leaf, were not detected at the levels of the natural preservatives.