bluuebunny/crossref_metadata_2025 huggingface dataset:
Frequency‐hopping signals sorting based on underdetermined blind source separation
Authors: Sha Zhi‐Chao , Huang Zhi‐Tao , Zhou Yi‐Yu , Wang Feng‐Hua
Published: September 2013

Most of the earlier approaches for frequency‐hopping (FH) signals sorting with a single sensor do not adapt to synchronous network, whereas the multiple‐sensor‐based algorithms request the number of sensors must be more than that of signals. Since the number of sensors is limited in many practical applications, it is important to sort synchronous or asynchronous FH networks with as little as possible sensors. This study introduces the underdetermined blind source separation (UBSS) algorithm to solve this problem. Considering the time–frequency (TF) sparsity of FH signals, the problem is formulated as one of UBSS based on sparse TF representation. First, an improved k‐means clustering algorithm is developed to estimate the mixing matrix, according to the TF properties of FH signals. Secondly, to separate more signals overlapped in the TF domain using given sensors, an improved subspace‐based algorithm utilising the information of the comparative power is proposed. In the proposed method, the sparsity condition of the sources in the TF domain is relaxed, and the number of FH signals that exist at any TF point simultaneously is allowed to equal that of the sensors. Simulations demonstrate that the proposed method can separate FH signals efficiently and outperforms the previous methods.
Efficient heuristic‐based approach for multi‐objective capacitor allocation in radial distribution networks
Authors: El‐Fergany Attia A. , Abdelaziz Almoataz Y.
Published: September 2013

This study introduces a heuristic‐based approach to allocate static capacitors along radial distribution networks using an accelerated particle swarm optimisation algorithm. In general practice, high potential buses for capacitor placement are initially identified using power loss indices. However, that method has proven less than satisfactory as power loss indices may not always indicate appropriate placement. In the proposed approach, the algorithm identifies optimal sizing and placement and takes the final decision for optimum location within the number of buses nominated. The result is enhancement of the overall system voltage stability index and potential achievement of maximum net savings. Sizing of fixed and switchable capacitors has been considered for different loading conditions. The overall accuracy and reliability of the approach have been validated and tested on radial distribution systems with differing topologies and of varying sizes and complexities. In this study, the results are compared with those obtained using recent heuristic methods and show that the proposed approach is capable of producing high‐quality solutions with good performance of convergence and demonstrated viability.
Focusing time harmonic scalar fields in non-homogenous lossy media: Inverse filter vs. constrained power focusing optimization
Authors: Iero D. A. M. , Isernia T. , Crocco L.
Published: September 2013

Two strategies to focus time harmonic scalar fields in known inhomogeneous lossy media are compared. The first one is the Inverse Filter (IF) method, which faces the focusing task as the synthesis of a nominal field. The second one is the Constrained Power Focusing Optimization (CPFO) method, which tackles the problem in terms of constrained mask constrained power optimization. Numerical examples representative of focusing in noninvasive microwave hyperthermia are provided to show that CPFO is able to outperform IF, thanks to the additional degrees of freedom arising from the adopted power synthesis formulation.
Attractors for the semilinear reaction-diffusion equation with distribution derivatives
Authors: Xie Yongqin , Li Qingsong , Huang Chuangxia , Jiang Yingjun
Published: September 2013

We investigate the asymptotic behavior of solutions to a nonlinear reaction-diffusion equation with distribution derivatives in the inhomogeneous term. Because the solutions of this equation are not very regular, i.e., u only belongs to \documentclass[12pt]{minimal}\begin{document}$L^p(\mathbb {R}^n)\cap H^1(\mathbb {R}^n)$\end{document}Lp(Rn)∩H1(Rn), and ut is only in \documentclass[12pt]{minimal}\begin{document}$H^{-1}(\mathbb {R}^n)$\end{document}H−1(Rn) for the forcing term in \documentclass[12pt]{minimal}\begin{document}$H^{-1}(\mathbb {R}^n)$\end{document}H−1(Rn), the standard method does not directly work in our case. We demonstrate the asymptotic regularity of the solution to obtain the \documentclass[12pt]{minimal}\begin{document}$(L^2(\mathbb {R}^n),H^1(\mathbb {R}^n))$\end{document}(L2(Rn),H1(Rn))-asymptotic compactness of the semigroup and therefore the existence of a \documentclass[12pt]{minimal}\begin{document}$(L^2(\mathbb {R}^n),H^1(\mathbb {R}^n))$\end{document}(L2(Rn),H1(Rn))-global attractor. In particular cases, our results enable us to improve on some previously known results.
Capturing inhomogeneous broadening of the –CN stretch vibration in a Langmuir monolayer with high-resolution spectra and ultrafast vibrational dynamics in sum-frequency generation vibrational spectroscopy (SFG-VS)
Authors: Velarde Luis , Wang Hong-fei
Published: September 2013

While in principle the frequency-domain and time-domain spectroscopic measurements should generate identical information for a given molecular system, the inhomogeneous character of surface vibrations in sum-frequency generation vibrational spectroscopy (SFG-VS) studies has only been studied with time-domain SFG-VS by mapping the decay of the vibrational polarization using ultrafast lasers, this due to the lack of SFG vibrational spectra with high enough spectral resolution and accurate enough lineshape. Here, with the recently developed high-resolution broadband SFG-VS (HR-BB-SFG-VS) technique, we show that the inhomogeneous lineshape can be obtained in the frequency-domain for the anchoring CN stretch of the 4-n-octyl-4′-cyanobiphenyl (8CB) Langmuir monolayer at the air-water interface, and that an excellent agreement with the time-domain SFG free-induction-decay can be established. We found that the 8CB CN stretch spectrum consists of a single peak centered at 2234.00 ± 0.01 cm−1 with a total linewidth of 10.9 ± 0.3 cm−1 at half maximum. The Lorentzian contribution accounts only for 4.7 ± 0.4 cm−1 to this width and the Gaussian (inhomogeneous) broadening for as much as 8.1 ± 0.2 cm−1. Polarization analysis of the –CN spectra showed that the –CN group is tilted 57° ± 2° from the surface normal. The large heterogeneity in the –CN spectrum is tentatively attributed to the –CN group interactions with the interfacial water molecules penetrated/accommodated into the 8CB monolayer, a unique phenomenon for the nCB Langmuir monolayers reported previously.
On the uniqueness of t → 0+ quantum transition-state theory
Authors: Hele Timothy J. H. , Althorpe Stuart C.
Published: September 2013

It was shown recently that there exists a true quantum transition-state theory (QTST) corresponding to the t → 0+ limit of a (new form of) quantum flux-side time-correlation function. Remarkably, this QTST is identical to ring-polymer molecular dynamics (RPMD) TST. Here, we provide evidence which suggests very strongly that this QTST (≡ RPMD-TST) is unique, in the sense that the t → 0+ limit of any other flux-side time-correlation function gives either non-positive-definite quantum statistics or zero. We introduce a generalized flux-side time-correlation function which includes all other (known) flux-side time-correlation functions as special limiting cases. We find that the only non-zero t → 0+ limit of this function that contains positive-definite quantum statistics is RPMD-TST.
Simulations of nanocrystals under pressure: Combining electronic enthalpy and linear-scaling density-functional theory
Authors: Corsini Niccolò R. C. , Greco Andrea , Hine Nicholas D. M. , Molteni Carla , Haynes Peter D.
Published: September 2013

We present an implementation in a linear-scaling density-functional theory code of an electronic enthalpy method, which has been found to be natural and efficient for the ab initio calculation of finite systems under hydrostatic pressure. Based on a definition of the system volume as that enclosed within an electronic density isosurface [M. Cococcioni, F. Mauri,G. Ceder, and N. Marzari, Phys. Rev. Lett.94, 145501 (2005)]10.1103/PhysRevLett.94.145501, it supports both geometry optimizations and molecular dynamics simulations. We introduce an approach for calibrating the parameters defining the volume in the context of geometry optimizations and discuss their significance. Results in good agreement with simulations using explicit solvents are obtained, validating our approach. Size-dependent pressure-induced structuraltransformations and variations in the energy gap of hydrogenated siliconnanocrystals are investigated, including one comparable in size to recent experiments. A detailed analysis of the polyamorphic transformationsreveals three types of amorphousstructures and their persistence on depressurization is assessed.
A theoretical study of crystallochromy: Spectral tuning of solid-state tetracenes
Authors: Fujimoto Kazuhiro J. , Kitamura Chitoshi
Published: September 2013

The crystallochromy of the red and yellow solids of tetracenes was theoretically investigated using the transition-density-fragment interaction combined with transfer integral method [K. J. Fujimoto, J. Chem. Phys. 137, 034101 (2012)10.1063/1.4733669]. The calculated absorption and fluorescence energies were in good agreement with the experimental values for both solids. The spectral tuning mechanism was analyzed in terms of three contributions: side-chain conformational effect, electrostatic solid-state effect, and multimerization effect. This analysis provided an insight into the mechanism of the large spectral shift between the two solids. The multimerization effect was found to be primarily important for the large red-shift of the red solid. Further analysis also revealed the strong dependence of the excited state character on the molecular displacement. Such dependence was found to have a significant influence on the magnitudes of the absorption energy and oscillator strength. These results indicated that the present approach is useful for analyzing and understanding the mechanism of crystallochromy.
Low-temperature hopping dynamics with energy disorder: Renormalization group approach
Authors: Velizhanin Kirill A. , Piryatinski Andrei , Chernyak Vladimir Y.
Published: September 2013

We formulate a real-space renormalization group (RG) approach for efficient numerical analysis of the low-temperature hopping dynamics in energy-disordered lattices. The approach explicitly relies on the time-scale separation of the trapping/escape dynamics. This time-scale separation allows to treat the hopping dynamics as a hierarchical process, RG step being a transformation between the levels of the hierarchy. We apply the proposed RG approach to analyze hopping dynamics in one- and two-dimensional lattices with varying degrees of energy disorder, and find the approach to be accurate at low temperatures and computationally much faster than the brute-force direct diagonalization. Applicability criteria of the proposed approach with respect to the time-scale separation and the maximum number of hierarchy levels are formulated. RG flows of energy distribution and pre-exponential factors of the Miller-Abrahams model are analyzed.
Damped harmonic system modeling of post-impact drop-spread dynamics on a hydrophobic surface
Authors: Manglik Raj M. , Jog Milind A. , Gande Sandeep K. , Ravi Vishaul
Published: September 2013

The post-impact spread, recoil, and shape oscillations of a droplet impinging on a dry horizontal hydrophobic substrate at low Weber numbers (We) (9.0 < We < 25) are modeled as the behavior of a second-order damped harmonic system. Experiments were conducted to capture the spread dynamics of droplets of six different liquids impinging on a Teflon substrate using a high speed digital visualization and image processing. The selected liquids cover a wide range of viscosities and surface tension coefficients, and their Ohnesorge and Capillary numbers vary by three orders of magnitude (0.002 ≤ Oh ≤ 1.57; 0.007 ≤ Ca ≤ 7.59). High-resolution photographic images of the post-impact spread-recoil process at different We are analyzed to obtain the temporal variations of the spread factor (ratio of liquid spread to droplet diameter) and the flatness factor (ratio of liquid height to droplet diameter). These are found to be represented by the damped harmonic response of a mass-spring-damper system, where the surface tension force acts as a spring and liquid viscosity provides the damping. Due to contact angle hysteresis, the frequency of oscillations for the transient flatness factor variation is slightly different from that for the spread factor variation. Semi-empirical correlations are developed for both the oscillation frequency and the damping factor as a function of drop Weber and Reynolds numbers. The predictions of temporal variations of the spread and flatness factors from these equations agree very well with experimental measurements on the hydrophobic Teflon substrate.
Critical edge behavior in the modified Jacobi ensemble and the Painlevé V transcendents
Authors: Xu Shuai-Xia , Zhao Yu-Qiu
Published: September 2013

We study the Jacobi unitary ensemble defined by the perturbed Chebyshev weight \documentclass[12pt]{minimal}\begin{document}$w(x)=(1-x^2)^{-\frac{1}{2}}(t_n^2-x^2)^{\alpha }$\end{document}w(x)=(1−x2)−12(tn2−x2)α, x ∈ (−1, 1), tn > 1. The algebraic singularity coalesces with the end point of the support of the weight function, namely, tn → 1, the hard edge, as n → ∞. We use the Riemann-Hilbert approach (the method of Deift and Zhou) to obtain the asymptotics of the polynomials orthogonal with respect to w(x). We show that the universality property is preserved: the asymptotic behavior of the eigenvalue correlations in the bulk of the spectrum is described in terms of the sine kernel. The main result is on the local behavior at the edge of the spectrum. The limit kernel at the edge, when tn − 1 = O(n−2), is described by the ψ −function for a specific solution of the Painlevé V equation. We also show that when tn varies to a fixed t > 1, the Painlevé V kernel transits to the Bessel kernel \documentclass[12pt]{minimal}\begin{document}$\mathbb {J}_{-\frac{1}{2}}$\end{document}J−12. On the other hand, when tn approaches 1, the Painlevé V kernel can be approximated by another Bessel kernel \documentclass[12pt]{minimal}\begin{document}$\mathbb {J}_{\alpha -\frac{1}{2}}$\end{document}Jα−12.
Time dependent solutions for a fractional Schrödinger equation with delta potentials
Authors: Lenzi E. K. , Ribeiro H. V. , dos Santos M. A. F. , Rossato R. , Mendes R. S.
Published: September 2013

We investigate, for an arbitrary initial condition, the time dependent solutions for a fractional Schrödinger equation in the presence of delta potentials by using the Green function approach. The solutions obtained show an anomalous spreading asymptotically characterized by a power-law behavior, which is governed by the order of the fractional spatial operator present in the Schrödinger equation.
Energy cascades in physical scales of 3D incompressible magnetohydrodynamic turbulence
Authors: Bradshaw Z. , Grujić Z.
Published: September 2013

The existence of a total energy cascade and the scale-locality of the total energy flux are rigorously established working directly from the 3D magnetohydrodynamic equations and under assumptions consistent with physical properties of turbulent plasmas. Secondary results are included identifying scenarios where inertial effects on specific energies effect cascade-like behavior as well as a scenario in which the inter-field energy transfer is predominantly from the fluid to the magnetic field.
Phase transformations in methanol at high pressure measured by dielectric spectroscopy technique
Authors: Kondrin M. V. , Pronin A. A. , Lebed Y. B. , Brazhkin V. V.
Published: September 2013

The dielectric response in methanol measured in wide pressure and temperature ranges (P < 6.0 GPa; 100 K < T < 360 K) reveals a series of anomalies which can be interpreted as a transformation between several solid phases of methanol including a hitherto unknown high-pressure low-temperature phase with the stability range P > 1.2 GPa and T < 270 K. In the intermediate P-T region P ≈ 3.4–3.7 GPa, T ≈ 260–280 K, a set of complicated structural transformations occurs involving four methanol crystalline structures. At higher pressures within the narrow range P ≈ 4.3–4.5 GPa methanol can be obtained in the form of fragile glass (Tg ≈ 200 K, mp ≈ 80 at P = 4.5 GPa) by relatively slow cooling.
Nanoscale structural and electrical evolution of Ta- and Ti-based contacts on AlGaN/GaN heterostructures
Authors: Greco G. , Giannazzo F. , Iucolano F. , Lo Nigro R. , Roccaforte F.
Published: September 2013

In this paper, the nanoscale structural and electrical evolution of Ta- and Ti-based contacts was investigated employing several analytical techniques. A correlation between the improvement of the electrical quality of the contacts and the formation of Al-alloyed phases (TaAl3 or TiAl3) during annealing was observed. However, while for the Ti/Al contacts an Ohmic behavior with a contact resistance Rc ∼ 1.8 Ω mm has been achieved after annealing at 500 °C, Ta/Al contacts exhibited a higher contact resistance (Rc ∼ 36.3 Ω·mm) even after annealing at 700 °C. The different electrical behaviour has been explained considering the different interface and the homogeneity of the current transport at a nanoscale level.
A super hierarchy of the vector nonlinear Schrödinger equations and Hamiltonian structures, conservation laws
Authors: He Guoliang , Zhai Yunyun , Geng Xianguo
Published: September 2013

A super hierarchy of the vector nonlinear Schrödinger equations associated with the 3 × 3 matrix spectral problem is proposed by using the Lenard recursion equations and the zero-curvature equation. The corresponding super bi-Hamiltonian structures are established with the help of the super trace identity. Furthermore, we derive the infinite conservation flows of the super vector nonlinear Schrödinger equation and the second equation in the hierarchy by utilizing spectral parameter expansions.
How many invariant polynomials are needed to decide local unitary equivalence of qubit states?
Authors: Maciążek Tomasz , Oszmaniec Michał , Sawicki Adam
Published: September 2013

Given L-qubit states with the fixed spectra of reduced one-qubit density matrices, we find a formula for the minimal number of invariant polynomials needed for solving local unitary (LU) equivalence problem, that is, problem of deciding if two states can be connected by local unitary operations. Interestingly, this number is not the same for every collection of the spectra. Some spectra require less polynomials to solve LU equivalence problem than others. The result is obtained using geometric methods, i.e., by calculating the dimensions of reduced spaces, stemming from the symplectic reduction procedure.
The effect of finite Larmor radius corrections on Jeans instability of quantum plasma
Authors: Sharma Prerana , Chhajlani R. K.
Published: September 2013

The influence of finite Larmor radius (FLR) effects on the Jeans instability of infinitely conducting homogeneous quantum plasma is investigated. The quantum magnetohydrodynamic (QMHD) model is used to formulate the problem. The contribution of FLR is incorporated to the QMHD set of equations in the present analysis. The general dispersion relation is obtained analytically using the normal mode analysis technique which is modified due to the contribution of FLR corrections. From general dispersion relation, the condition of instability is obtained and it is found that Jeans condition is modified due to quantum effect. The general dispersion relation is reduced for both transverse and longitudinal mode of propagations. The condition of gravitational instability is modified due to the presence of both FLR and quantum corrections in the transverse mode of propagation. In longitudinal case, it is found to be unaffected by the FLR effects but modified due to the quantum corrections. The growth rate of Jeans instability is discussed numerically for various values of quantum and FLR corrections of the medium. It is found that the quantum parameter and FLR effects have stabilizing influence on the growth rate of instability of the system.
Bipolar resistance switching and photocurrent in a BaTiO3-δ thin film
Authors: Park Y. A. , Sung K. D. , Won C. J. , Jung J. H. , Hur N.
Published: September 2013

The leakage current in ferroelectric materials has been considered as a problem to be overcome in ferroelectric memory applications. However, recent studies on the polarization-dependent diode effect and the photocurrent in lossy ferroelectric materials suggest the possibility of using this leakage current for a different type of resistive memory. Along this route, we investigated the resistance-switching effect in SrRuO3/BaTiO3-δ/SrRuO3 thin film capacitors. We observed the bipolar resistance switching and the switchable photocurrent, both of which were tuned by the different electric poling. Our finding may suggest an alternative type of nonvolatile ferroelectric memory capable of nondestructive readout.
Performance of Cu(In,Ga)Se2 solar cells using nominally alkali free glass substrates with varying coefficient of thermal expansion
Authors: Hultqvist A. , Salomé P. M. P. , Fjällström V. , Edoff M. , Aitken B. , Zhang K. , Shi Y. , Fuller K. , Williams C. Kosik
Published: September 2013

In this report, Cu(In,Ga)Se2, CIGS, solar cell devices have been fabricated on nominally alkali free glasses with varying coefficients of thermal expansion (CTE) from 50 to 95 * 10−7/ °C. A layer of NaF deposited on top of the Mo was used to provide Na to the CIGS film. Increasing the glass CTE leads to a change of stress state of the solar cell stack as evidenced by measured changes of stress state of the Mo layer after CIGS deposition. The open circuit voltage, the short circuit current density, and the fill factors, for solar cells made on the various substrates, are all found to increase with CTE to a certain point. The median energy conversion efficiency values for 32 solar cells increases from 14.6% to the lowest CTE glass to 16.5% and 16.6%, respectively, for the two highest CTE glasses, which have CTE values closest to that of the soda lime glass. This is only slightly lower than the 17.0% median of soda lime glass reference devices. We propose a model where an increased defect density in the CIGS layer caused by thermal mismatch during cool-down is responsible for the lower efficiency for the low CTE glass substrates.
Study on the thermal stability improvement of GeTe by Al doping
Authors: Ren Kun , Rao Feng , Song Zhitang , Peng Cheng , Li Juntao , Wu Liangcai , Liu Bo , Feng Songlin
Published: September 2013

Al-doped GeTe is proposed for high-temperature phase-change memories (PCM). The bonding and coordination environment of Al atoms in Al2.7Ge50Te50 is studied by X-ray photoelectron spectroscopy and nuclear magnetic resonance. The large number of bonds provided by Al improves the stability of the amorphous-state (10-yr retention at 177 °C) as well as the uniformity of the material distribution. The low melting temperature (676 °C) and high set-resistance lower power-consumption of the Al2.7Ge50Te50 based cell. The high thermal stability and low power-consumption have made Al2.7Ge50Te50 material a promising candidate for high thermally stable PCM application.
Experimental evaluation of impact ionization in dilute nitride GaInNAs diodes
Authors: Tan S. L. , Soong W. M. , Green J. E. , Steer M. J. , Zhang S. , Tan L. J. J. , Ng J. S. , Marko I. P. , Sweeney S. J. , Adams A. R. , Allam J. , David J. P. R.
Published: September 2013

The anomalous behavior of impact ionization in dilute-nitride GaInNAs photodiodes with a range of nitrogen content below 4% is investigated. The ratio of hole- and electron-initiated ionization coefficients, k = β/α, is enhanced by a factor up to ∼4 with increasing nitrogen content. The absolute ionization coefficients are suppressed by up to two orders of magnitude at low electric fields in samples with 3% N. The narrow band gap, suppressed impact ionization, and increased breakdown voltage characteristics of GaInNAs make it a suitable material for use as part of a composite collector in GaAs-based heterojunction bipolar transistors.
Ultra low-K shrinkage behavior when under electron beam in a scanning electron microscope
Authors: Lorut F. , Roggero A. , Imbert G.
Published: September 2013

In this paper, we investigate the tendency of porous low-K dielectrics (also named Ultra Low-K, ULK) behavior to shrink when exposed to the electron beam of a scanning electron microscope. Various experimental electron beam conditions have been used for irradiating ULK thin films, and the resulting shrinkage has been measured through use of an atomic force microscope tool. We report the shrinkage to be a fast, cumulative, and dose dependent effect. Correlation of the shrinkage with incident electron beam energy loss has also been evidenced. The chemical modification of the ULK films within the interaction volume has been demonstrated, with a densification of the layer and a loss of carbon and hydrogen elements being observed.
Transition of electron transport process in Be-doped low-temperature-grown GaAs layer
Authors: Mohamed Mohd Ambri , Tien Lam Pham , Otsuka N.
Published: September 2013

Effects of the structure change of antisite-As (AsGa) defects on the electron transport property in Be-doped low-temperature-grown GaAs layers were investigated. In this material, AsGa atoms cooperatively change their positions between substitutional and interstitial sites. We found an abrupt change in the resistance of a sample at a temperature around 3 K, where a discontinuous decrease of the magnetization was also observed. The mechanism of the transition of the electron transport property is explained by first-principles calculations of the electron state of an AsGa atom accompanied with a shallow acceptor Be atom. At the transition, AsGa+ ions are cooperatively displaced to interstitial sites and become neutral atoms, which result in generation of holes in the valence band. The mechanism of the discontinuous change of the electron transport process in this material is discussed in connection with existing mechanisms such as those of metal-insulator transitions.
Effect of gamma irradiation on opto-structural, dielectric, and thermoluminescence properties of natural phlogopite mica
Authors: Kaur Sukhnandan , Singh Surinder , Singh Lakhwant , Lochab S. P.
Published: September 2013

Gamma ray induced modifications in natural phlogopite mica have been studied in the dose range of 1–2000 kGy. These modifications were monitored using different techniques viz: ultraviolet-visible spectroscopy, Fourier Transform Infrared spectroscopy, dielectric measurements, X-ray diffraction, and thermoluminescence dosimeter. The analysis of the results reveals that the dose of 100 kGy produces significant change in the natural phlogopite mica as compared to pristine and other exposed samples. Ultraviolet-visible analysis provides the value of optical indirect, direct band gap, and Urbach energy. Cody model was used to calculate structural disorder from Urbach energy. Different dielectric parameters such as dielectric constant, dielectric loss, ac conductivity, and real and imaginary parts of electric modulus were calculated for pristine and irradiated samples at room temperature. Williamson Hall analysis was employed to calculate crystallite size and micro-strain of pristine and irradiated sheets. No appreciable changes in characteristic bands were observed after irradiation, indicating that natural phlogopite mica is chemically stable. The natural phlogopite mica may be recommended as a thermoluminescent dosimeter for gamma dose within 1 kGy–300 kGy.
Influence of transfer residue on the optical properties of chemical vapor deposited graphene investigated through spectroscopic ellipsometry
Authors: Matković Aleksandar , Ralević Uroš , Chhikara Manisha , Jakovljević Milka M. , Jovanović Djordje , Bratina Gvido , Gajić Radoš
Published: September 2013

In this study, we have examined the effects of transfer residue and sample annealing on the optical properties of chemical vapor deposited graphene, transferred onto a sapphire substrate. The optical absorption of graphene was obtained from point-by-point inversion of spectroscopic ellipsometry measurements in the visible and ultraviolet ranges (250–800 nm). Measured spectra were analyzed by optical models based on the Fresnel coefficient equations. The optical models were supported by correlated Raman, scanning electron microscopy, and atomic force microscopy measurements. The obtained data were phenomenologically described by a Fano model. Our results show that a residue layer left on graphene can significantly increase its optical absorption in the visible range, compared to an annealed sample.
Dual-frequency bistable reflective cholesteric liquid crystal displays based on chiral-flexoelectric polarisation dispersion
Authors: Outram B. I. , Elston S. J.
Published: September 2013

A new approach to switching between states in reflective cholesteric liquid crystal displays is demonstrated that relies on the dispersion in the cholesteric material's dielectric properties due to flexoelectricity. Flexoelectric polarisation allows the device to be switched into a weakly scattering focal-conic state at low frequencies, while at higher frequencies the device is driven into the reflective Grandjean state. The non-conventional dual-frequency effect allows driving between states in both directions. The cross-over frequency can be as low as 300 Hz, orders of magnitude smaller than other dual-frequency effects. Devices of various reflective colours are demonstrated and have favourable contrast ratios, viewing angles, and switching behaviours at room temperature. The technique potentially affords a greater flexibility in surface alignment conditions, driving schemes, material parameters, and use of polymer networks in cholesteric devices than other switching methods.
Elastic constants of polycrystalline L1-FePt at high temperatures
Authors: Nakamura N. , Yoshimura N. , Ogi H. , Hirao M.
Published: September 2013

Elastic constants of polycrystalline L10 FePt are studied from room temperature up to 1073 K by the electromagnetic acoustic resonance. The longitudinal-wave stiffness and the bulk modulus show intermediate values of polycrystalline Fe and Pt, but the shear modulus and Young's modulus show larger value than those of polycrystalline Fe and Pt. The Blackman diagram indicates that L10 FePt exhibits a tendency toward covalent-bond characteristic. Strong anharmonicity of the interatmoic potential is confirmed from the temperature coefficient of the bulk modulus.
Free-space coupled, ultralow-threshold Raman lasing from a silica microcavity
Authors: Jiang Xue-Feng , Xiao Yun-Feng , Yang Qi-Fan , Shao Linbo , Clements William R. , Gong Qihuang
Published: September 2013

We report Raman lasing in a slightly deformed silica microcavity using an efficient free-space coupling technique, with an absorbed pump threshold as low as 100 μW in the 1550 nm wavelength band. This ultralow threshold originates from the ultrahigh quality factors of whispering gallery modes, exceeding 108, even though the microcavity is deformed from a circular symmetry. Furthermore, the threshold of free-space coupled Raman lasing is experimentally demonstrated to show a strict inverse square dependence on the intrinsic quality factor of the cavity mode, which agrees well with the theoretical prediction.
Reduced thermal conductivity in Er-doped epitaxial InxGa1−xSb alloys
Authors: Feser Joseph P. , Xu Dongyan , Lu Hong , Zhao Yang , Shakouri Ali , Gossard Arthur C. , Majumdar Arun
Published: September 2013

The thermal conductivity of epitaxially grown semiconducting alloys of InxGa1−xSb is studied and compared to Er doped alloys. At concentrations as low as ∼0.4% vol. Er, the Er coalesces to form epitaxially embedded ErSb nanocrystals which reduce the thermal conductivity compared to undoped alloys. The thermomechanical properties of epitaxial ErSb are studied for comparison. ErSb is found to be metallic with significantly higher thermal conductivity and stiffness than InxGa1−xSb alloys. The stiffness and density contrast from ErSb nanocrystals helps explain its high effectiveness as a phonon scattering center, as they are the highest of any known lattice matched material pair.
Enhanced and suppressed spontaneous emission from a buried heterostructure photonic crystal cavity
Authors: Takiguchi Masato , Sumikura Hisashi , Danang Birowosuto Muhammad , Kuramochi Eiichi , Sato Tomonori , Takeda Koji , Matsuo Shinji , Notomi Masaya
Published: September 2013

We study spontaneous emission control in a buried-heterostructure (BH) photonic crystal (PhC) cavity in which InGaAsP quantum wells (QWs) are embedded in an InP PhC. Spontaneous emission from QW-PhC cavities have been extensively investigated, but they suffer from poor carrier confinement and surface non-radiative recombination. Therefore, the clear spontaneous emission control has been only observed in quantum dots PhC cavities. The present study shows that the BH-QW-PhC cavities can exhibit distinctive spontaneous emission control in QW-PhCs. We observed large emission-rate ratio between the on- and off-resonant conditions of 30:1. This is the highest ratio reported for QW-PhCs.
Microwave assisted growth of copper germanide thin films at very low temperatures
Authors: Das Sayantan , Alford T. L.
Published: September 2013

Herein the synthesis of Cu3Ge films by exposing Cu-Ge alloy films to microwave radiation is reported. It is shown that microwave radiation led to the formation of copper germanide at temperatures ca. 80 °C. The electrical properties of the Cu3Ge films are presented and compared for various annealing times. X-ray diffraction shows that the Cu3Ge films formed after microwave annealing is crystalline in the orthorhombic phase. Rutherford backscattering and X-ray photoelectron spectroscopy confirms the formation of copper oxide encapsulation layer. Despite the slight oxidation of Cu during the microwave anneal the lowest resistivity of Cu3Ge films obtained is 14 μΩ-cm.
Zwischen den Stühlen
Authors: Kaltz Barbara
Published: September 2013

In diesem Artikel werden zwei wichtige Arbeiten zur Geschichte der deutschen Sprache in Frankreich vorgestellt, die beide in methodischer Hinsicht an Ferdinand Brunot (1860–1938) orientiert sind. Paul Lévy (1887–1962), der Verfasser der beiden Werke Histoire linguistique d’Alsace et de Lorraine (1929) und La langue allemande en France: Pénétration et diffusion des origines à nos jours (1950, 1952), ist heute weitgehend vergessen. Nach einem kurzen Überblick über Leben und Werk wird die zeitgenössische Rezeption der beiden Schriften untersucht. Die erstgenannte Arbeit reichte Lévy 1929 an der Université de Strasbourg als Habilitationsschrift ein; sie wurde nach ihrem Erscheinen von vielen Fachwissenschaftlern im In- und Ausland positiv aufgenommen, während die Straßburger Germanisten ablehnend reagierten. Die Gründe für diese abweichende Einschätzung werden in dem Beitrag eingehend analysiert. Auch im Falle seiner Geschichte des Deutschen in Frankreich ist eine ähnliche Diskrepanz in der Rezeption festzustellen: grundsätzliche Kritik wurde wiederum in Frankreich geübt, während das Urteil von Germanisten und Romanisten in anderen Ländern insgesamt positiv ausfiel.
A little-known aspect of Leonard Bloomfield’s linguistics
Authors: Barnhart Cynthia A.
Published: September 2013

Leonard Bloomfield’s (1887–1949) contribution to the literature and theory of teaching reading is not widely known. This paper recounts the history of that contribution, published asLet’s Read: A linguistic approachin 1961, well after his death. Clarence L. Barnhart (1900–1993), the lexicographer, had encouraged Bloomfield to write a complete, finished manuscript of his phonemic approach to teaching reading and expended considerable time searching for a publisher. Bloomfield and Barnhart also sought classroom experimentation of Bloomfield’s materials before publication, which by and large verified his ideas, as did later experiments. Critical reception ofLet’s Read, which rejected familiar reading pedagogy, was not warmly welcoming, especially among reading professionals, while linguists like the Romanist Yakov Malkiel (1914–1998) and the structuralist Henry Lee Smith (1913–1972) offered more positive assessments.
Respiratory virus–induced EGFR activation suppresses IRF1-dependent interferon λ and antiviral defense in airway epithelium
Authors: Ueki Iris F. , Min-Oo Gundula , Kalinowski April , Ballon-Landa Eric , Lanier Lewis L. , Nadel Jay A. , Koff Jonathan L.
Published: September 2013

Viruses suppress host responses to increase infection, and understanding these mechanisms has provided insights into cellular signaling and led to novel therapies. Many viruses (e.g., Influenza virus, Rhinovirus [RV], Cytomegalovirus, Epstein-Barr virus, and Hepatitis C virus) activate epithelial epidermal growth factor receptor (EGFR), a tyrosine kinase receptor, but the role of EGFR in viral pathogenesis is not clear. Interferon (IFN) signaling is a critical innate antiviral host response and recent experiments have implicated IFN-λ, a type III IFN, as the most significant IFN for mucosal antiviral immune responses. Despite the importance of IFN-λ in epithelial antiviral responses, the role and mechanisms of epithelial IFN-λ signaling have not been fully elucidated. We report that respiratory virus-induced EGFR activation suppresses endogenous airway epithelial antiviral signaling. We found that Influenza virus– and RV-induced EGFR activation suppressed IFN regulatory factor (IRF) 1–induced IFN-λ production and increased viral infection. In addition, inhibition of EGFR during viral infection augmented IRF1 and IFN-λ, which resulted in decreased viral titers in vitro and in vivo. These findings describe a novel mechanism that viruses use to suppress endogenous antiviral defenses, and provide potential targets for future therapies.
Neuroprotective intervention by interferon-γ blockade prevents CD8+ T cell–mediated dendrite and synapse loss
Authors: Kreutzfeldt Mario , Bergthaler Andreas , Fernandez Marylise , Brück Wolfgang , Steinbach Karin , Vorm Mariann , Coras Roland , Blümcke Ingmar , Bonilla Weldy V. , Fleige Anne , Forman Ruth , Müller Werner , Becher Burkhard , Misgeld Thomas , Kerschensteiner Martin , Pinschewer Daniel D. , Merkler Doron
Published: September 2013

Neurons are postmitotic and thus irreplaceable cells of the central nervous system (CNS). Accordingly, CNS inflammation with resulting neuronal damage can have devastating consequences. We investigated molecular mediators and structural consequences of CD8+ T lymphocyte (CTL) attack on neurons in vivo. In a viral encephalitis model in mice, disease depended on CTL-derived interferon-γ (IFN-γ) and neuronal IFN-γ signaling. Downstream STAT1 phosphorylation and nuclear translocation in neurons were associated with dendrite and synapse loss (deafferentation). Analogous molecular and structural alterations were also found in human Rasmussen encephalitis, a CTL-mediated human autoimmune disorder of the CNS. Importantly, therapeutic intervention by IFN-γ blocking antibody prevented neuronal deafferentation and clinical disease without reducing CTL responses or CNS infiltration. These findings identify neuronal IFN-γ signaling as a novel target for neuroprotective interventions in CTL-mediated CNS disease.
Introduction
Authors: Matilal Bimal Krishna
Published: September 2013

This book introduces, discusses, and tries to defend a form of realism called Nyāya realism simply because this stands closest to the position upheld by the adherents of the Nyāya school in the Indian philosophical tradition. Historically this position is pitted against Buddhist phenomenalism and idealism. The book mainly presents Nyāya realism and Buddhist phenomenalism in their historical context. It also attempts, if only impressionistically, to show what place Buddhist phenomenalism occupies in the whole range of such philosophical views as ‘sense data’ theory, scientific phenomenalism, and rcprcsentationalism, and whether arguments in favour of Nyāya realism could counterbalance such views.
Philosophical Questions and Pramanas
Authors: Matilal Bimal Krishna
Published: September 2013

In the Western tradition, epistemology is the name given to that branch of philosophy which deals with the theory of knowledge, that is to say, the attempted vindication of the reliability of claims to knowledge. It investigates and evaluates evidence, the method of reasoning, and the criteria upon which knowledge-claims are based. The function of what is called the pramāna-́sāstra in Indian philosophic tradition coincides to a great extent with this activity. The strong claim of some philosophers of classical India was that conception without perception is ‘empty’. The counter-claim was that perception without conception is ‘blind’. This chapter examines different philosophical theories of perception of classical Indian origin in the context of the pramāna epistemology. It gives a brief outline of the pramāna doctrine as well as the kind of scepticism that gave rise to it.
Knowing that One Knows
Authors: Matilal Bimal Krishna
Published: September 2013

It is generally agreed that if something is known, it must be true or it must exist. Nyāya says that this fact does not allow one to say that if one knows then necessarily one knows that one knows and this holds even when one is quite convinced about what one knows. One may in fact be absolutely sure about what one cognizes but such a certainty by itself does not amount to knowledge. The first section of this chapter examines rival theories about knowledge of knowledge. The second section develops the Buddhist position on ‘self-awareness’. The third section explores the question ‘Must I be aware that I am aware?’ The fourth section analyzes the Nyāya view about knowing that one knows. The fifth section describes inference, confirmation, and introspection.
Analysis of Perceptual Illusion
Authors: Matilal Bimal Krishna
Published: September 2013

Sensory (perceptual) illusion is said to be ‘promiscuous’ in Nyāya. Promiscuity of awareness here means that it deals with two ‘objects’ at the same time. ‘Illusion’ is used for cases where something is seen but looks to be other than it is or is ‘taken’ to be. The first section of this chapter describes seeing and seeing-as. The second section considers two Buddhist analyses of illusion. The third section explores the Advaita view of the inexplicability of the appearance. The fourth section considers the Prābhākara view of no-illusion. The fifth section expounds the Nyāya analysis of illusion, which is called the ‘misplacement’ theory. The sixth section explains fictions and fantasies. The last section compares sense-datum and direct realism.
What Do We See?
Authors: Matilal Bimal Krishna
Published: September 2013

The problems of perception are generally discussed in the Western context with reference to three main theories. These theories are about what one can directly know, and how one knows it. They are naïve or direct realism, representationalism, and phenomenalism. The second section of this chapter discusses the Nyaysutra definition of perception. The third section looks at Vasubandhu's illusionism. The fourth section considers a case where the external world does not exist. The fifth section considers as case where the external world does exist. The sixth section examines the Abhidharma phenomenalism. The seventh section discusses nominal existence and substantial existence. The last section explores colour and shape with regards to Molyneux's question.
Pleasure and Pain
Authors: Matilal Bimal Krishna
Published: September 2013

Can there be unfelt pain, or unsensed pleasure? Could there be pain in me which I have not experienced? Could there be pleasure that has occurred for me, but which I have not felt? These questions are pertinent. They illuminate a controversy between Nyāya and Buddhism over the nature of the perception of ‘inner’ episodes. Philosophers generally have been of the opinion that there cannot be any ‘unfelt pleasure’ or ‘unsensed pain’. Now the question arises whether or not pleasures and pains are to be identified with, or be considered as an integral part of the awareness itself. The Buddhist here follows the common intuition, and argues that the arising of pain-sensation or pleasure-sensation is nothing but a special form or kind of cognitive episode called the inner perceptual awareness.
Particulars
Authors: Matilal Bimal Krishna
Published: September 2013

The first section of this chapter discusses three rival ontologies in the Indian context. The Buddhist envisions a world populated by phenomenal particulars. These are called the svalaḳsạnas, ‘self-characterized’. They include both physical phenomena such as colour-patches and mental phenomena, cognitive events and other ‘mental’ bits concomitant with them (mimi). The Nyāya–Vaíṣsika world is populated with three main types of particulars, certain (real) universals and one genuine relation. The particulars are substances, quality-instances, and action-moments. The third ontology is holistic. This is the view that says that the ultimate reality is one unbreakable, unstructured whole, which is the ultimate reference of all linguistic expressions and all thoughts. The second section discusses phenomenalism and atomism. The last section examines direct realism.
Promoter RNA links transcriptional regulation of inflammatory pathway genes
Authors: Matsui Masayuki , Chu Yongjun , Zhang Huiying , Gagnon Keith T. , Shaikh Sarfraz , Kuchimanchi Satya , Manoharan Muthiah , Corey David R. , Janowski Bethany A.
Published: September 2013

Although many long non-coding RNAs (lncRNAs) have been discovered, their function and their association with RNAi factors in the nucleus have remained obscure. Here, we identify RNA transcripts that overlap the cyclooxygenase-2 (COX-2) promoter and contain two adjacent binding sites for an endogenous miRNA, miR-589. We find that miR-589 binds the promoter RNA and activates COX-2 transcription. In addition to miR-589, fully complementary duplex RNAs that target the COX-2 promoter transcript activate COX-2 transcription. Activation by small RNA requires RNAi factors argonaute-2 (AGO2) and GW182, but does not require AGO2-mediated cleavage of the promoter RNA. Instead, the promoter RNA functions as a scaffold. Binding of AGO2 protein/small RNA complexes to the promoter RNA triggers gene activation. Gene looping allows interactions between the promoters of COX-2 and phospholipase A2 (PLA2G4A), an adjacent pro-inflammatory pathway gene that produces arachidonic acid, the substrate for COX-2 protein. miR-589 and fully complementary small RNAs regulate both COX-2 and PLA2G4A gene expression, revealing an unexpected connection between key steps of the eicosanoid signaling pathway. The work demonstrates the potential for RNA to coordinate locus-dependent assembly of related genes to form functional operons through cis-looping.