bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermochronometrically constrained anatomy and evolution of a Miocene extensional accommodation zone and tilt domain boundary: The southern Wassuk Range, Nevada
Authors: Gorynski Kyle E. , Stockli Daniel F. , Douglas Walker J.
Published: April 2013

Apatite (AHe) and Zircon (ZHe) (U‐Th)/He thermochronometric data from the southern Wassuk Range (WR) coupled with 40Ar/39Ar age data from the overlying tilted Tertiary section are used to constrain the thermal evolution of an extensional accommodation zone and tilt‐domain boundary. AHe and ZHe data record two episodes of rapid cooling related to the tectonic exhumation of the WR fault block beginning at ~15 and ~4 Ma. Extension was accommodated through fault‐block rotation and variably tilted the southern WR to the west from ~60°–70° in the central WR to ~15°–35° in the southernmost WR and Pine Grove Hills, and minimal tilting in the Anchorite Hills and along the Mina Deflection to the south. Middle Miocene geothermal gradient estimates record heating immediately prior to large‐magnitude extension that was likely coeval with the extrusion of the Lincoln Flat andesite at ~14.8 Ma. Geothermal gradients increase from ~19° ± 4°C/km to ≥ 65° ± 20°C/km toward the Mina Deflection, suggesting that it was the focus of Middle Miocene arc magmatism in the upper crust. The decreasing thickness of tilt blocks toward the south resulted from a shallowing brittle/ductile transition zone. Postmagmatic Middle Miocene extension and fault‐block advection were focused in the northern and central WR and coincidentally moderated the large lateral thermal gradient within the uppermost crust.
A kinematic model for the formation of the Siletz‐Crescent forearc terrane by capture of coherent fragments of the Farallon and Resurrection plates
Authors: McCrory Patricia A. , Wilson Douglas S.
Published: April 2013

The volcanic basement of the Oregon and Washington Coast ranges has been proposed to represent a pair of tracks of the Yellowstone hotspot formed at a mid‐ocean ridge during the early Cenozoic. This interpretation has been questioned on many grounds, especially that the range of ages does not match the offshore spreading rates and that the presence of continental coarse clastic sediments is difficult to reconcile with fast convergence rates between the oceanic plates and North America. Updates to basement geochronology and plate motion history reveal that these objections are much less serious than when they were first raised. Forward plate kinematic modeling reveals that predicted basement ages can be consistent with the observed range of about 55–49 Ma, and that the entire basement terrane can form within about 300 km of continental sources for clastic sediments. This kinematic model indicates that there is no firm reason to reject the near‐ridge hotspot hypothesis on the basis of plate motions. A novel element of the model is the Resurrection plate, previously proposed to exist between the Farallon and Kula plates. By including the defunct Resurrection plate in our reconstruction, we are able to model the Farallon hotspot track as docking against the Oregon subduction margin starting about 53 Ma, followed by docking of the Resurrection track to the north starting about 48 Ma. Accretion of the Farallon plate fragment and partial subduction of the Resurrection fragment complicates the three‐dimensional structure of the modern Cascadia forearc. We interpret the so‐called “E” layer beneath Vancouver Island to be part of the Resurrection fragment. Our new kinematic model of mobile terranes within the Paleogene North American plate boundary allows reinterpretation of the three‐dimensional structure of the Cascadia forearc and its relationship to ongoing seismotectonic processes.
Feedback stabilization of a simplified 1d fluid–particle system
Authors: Badra Mehdi , Takahashi Takéo
Published: April 2013

We consider the feedback stabilization of a simplified 1d model for a fluid–structure interaction system. The fluid equation is the viscous Burgers equation whereas the motion of the particle is given by the Newton's laws. We stabilize this system around a stationary state by using feedbacks located at the exterior boundary of the fluid domain. With one input, we obtain a local stabilizability of the system with an exponential decay rate of order

\sigma < \sigma _{0}

. An arbitrary order for the exponential decay rate can be proved if a unique continuation result holds true or if two inputs are used to stabilize the system. Our method is based on general arguments for stabilization of nonlinear parabolic systems combined with a change of variables to handle the fact that the fluid domains of the stationary state and of the stabilized solution are different.
N‐α‐acetyltransferase 10 protein is a negative regulator of 28S proteasome through interaction with PA28β
Authors: Min Li , Xu Huiyu , Wang Juan , Qu Like , Jiang Beihai , Zeng Yan , Meng Lin , Jin Hongwei , Shou Chengchao
Published: April 2013

Naa10p physically interacts with PA28 alpha and PA28 beta by anti bait coimmunoprecipitation (View Interaction: 1, 2)
90‐kDa ribosomal S6 kinase 1 is inhibited by S‐glutathionylation of its active‐site cysteine residue during oxidative stress
Authors: Takata Tsuyoshi , Tsuchiya Yukihiro , Watanabe Yasuo
Published: April 2013

Previously, we reported that p90‐RSK1 phosphorylates neuronal nitric oxide synthase (nNOS) at Ser847 in cells treated with mitogens, leading to the inhibition of NOS activity. Here, we show RSK1 Cys223 glutathionylation limits the activity of the enzyme following an oxidative stimulus and attenuates the nNOS phosphorylation. Treatment of RSK1 with diamide/glutathione results in inactivation of the enzyme in vitro. Mutagenesis studies confirmed that S‐glutathionylation of Cys223 is both necessary and sufficient for this inhibition of RSK1. In transfected cells expressing RSK1 and nNOS, treatment with diamide caused a decrease in EGF‐induced phosphorylation of nNOS at Ser847. Cells expressing mutant RSK1 (C223S) proved resistant in this regard. Thus, RSK1 Cys223 glutathionylation may contribute to regulate the levels of NO in the brain.
Muskel-Skelett-Erkrankungen: Bedeutung von Bewegungsmangel und sportlicher Aktivität
Authors: Wessinghage Thomas , Morsch Arne
Published: April 2013

Einleitung

Muskel-Skelett-Erkrankungen gehören in Deutschland zu den führenden Krankheitsbildern. Neben einer individuellen Krankheitslast verursachen sie hohe Belastungen für das Gesundheitssystem sowie hohe Fehlzeiten am Arbeitsplatz. Mit ausschlaggebend ist ein zunehmender Bewegungsmangel, der weltweit bereits 80% der Bevölkerung über 30 betrifft. Bei der Prävention von Muskel-Skelett-Erkrankungen können Trainingsinterventionen in Fitness- und Gesundheitseinrichtungen eine wesentliche Rolle spielen.
Deciphering late Quaternary land snail shell δ18O and δ13C from Franchthi Cave (Argolid, Greece)
Authors: Colonese André C. , Zanchetta Giovanni , Perlès Catherine , Drysdale Russell N. , Manganelli Giuseppe , Baneschi Ilaria , Dotsika Elissavet , Valladas Hélène
Published: April 2013

This paper investigates the stable isotopic composition from late Pleistocene–Holocene (~ 13 to ~ 10.5 cal ka BP) shells of the land snailHelix figulina, from Franchthi Cave (Greece). It explores the palaeoclimatic and palaeoenvironmental implications of the isotope palaeoecology of archaeological shells at the time of human occupation of the cave. Modern shells from around the cave were also analysed and their isotopic signatures compared with those of the archaeological shells. The carbon isotope composition of modern shells depicts the consumption of C3vegetation. Shell oxygen isotopic values are consistent with other Mediterranean snail shells from coastal areas. Combining empirical linear regression and an evaporative model, the δ18Os suggest that modern snails in the study area are active during periods of higher relative humidity and lower rainfall δ18O, probably at night. Late glacial and early Holocene δ18Os show lower values compared to modern ones. Early Holocene δ18Os values likely track enhanced moisture and isotopic changes in the precipitation source. By contrast, lower late glacial δ18O could reflect lower temperatures and δ18Op, compared to the present day. Shell carbon isotope values indicate the presence of C3vegetation as main source of carbon to late glacial and early Holocene snails.
Auskultation der Karotiden – Bedeutung eines Geräusches
Authors: Seiffge David , Lyrer Philippe
Published: April 2013

Karotisgeräusche (KG) alleine haben als prognostische Marker eine geringe Aussagekraft. Jedoch kann die Auskultation eines Geräusches über den Karotiden zur weiteren diagnostischen Abklärung mittels Ultraschall und zur Detektion einer asymptomatischen Stenose der A. carotis interna (ACI) führen. Hierfür weisen KGs eine befriedigende Spezifität, aber nur eine unzureichende Sensitivität auf. Auf Grund dieser Werte im Vergleich mit modernen, bildgebenden Verfahren (Ultraschall, MR-/CT-Angiographie) wurde häufig empfohlen, auf eine Auskultation der Karotiden zu verzichten. Gleichzeitig haben Patienten mit asymptomatischen ACI-Stenosen ein relevantes Hirnschlag-Risiko, welches mittels medikamentöser bzw. chirurgischer Therapie effektiv behandelt werden kann. Screeningverfahren mittels Ultraschall für ein nicht selektioniertes Patientenkollektiv sind teuer. Ein Screening von Risikopatienten mittels Karotisauskultation ist preiswert, wenn auch die Sensitivität niedrig ist.
Species‐specific impact of the autophagy machinery on Chikungunya virus infection
Authors: Judith Delphine , Mostowy Serge , Bourai Mehdi , Gangneux Nicolas , Lelek Mickaël , Lucas‐Hourani Marianne , Cayet Nadège , Jacob Yves , Prévost Marie‐Christine , Pierre Philippe , Tangy Frédéric , Zimmer Christophe , Vidalain Pierre‐Olivier , Couderc Thérèse , Lecuit Marc
Published: April 2013

Chikungunya virus (CHIKV) is a recently re‐emerged arbovirus that triggers autophagy. Here, we show that CHIKV interacts with components of the autophagy machinery during its replication cycle, inducing a cytoprotective effect. The autophagy receptor p62 protects cells from death by binding ubiquitinated capsid and targeting it to autophagolysosomes. By contrast, the human autophagy receptor NDP52—but not its mouse orthologue—interacts with the non‐structural protein nsP2, thereby promoting viral replication. These results highlight the distinct roles of p62 and NDP52 in viral infection, and identify NDP52 as a cellular factor that accounts for CHIKV species specificity.
Efficiently finding the minimum free energy path from steepest descent path
Authors: Chen Changjun , Huang Yanzhao , Ji Xiaofeng , Xiao Yi
Published: April 2013

Minimum Free Energy Path (MFEP) is very important in computational biology and chemistry. The barrier in the path is related to the reaction rate, and the start-to-end difference gives the relative stability between reactant and product. All these information is significant to experiment and practical application. But finding MFEP is not an easy job. Lots of degrees of freedom make the computation very complicated and time consuming. In this paper, we use the Steepest Descent Path (SDP) to accelerate the sampling of MFEP. The SHAKE algorithm and the Lagrangian multipliers are used to control the optimization of both SDP and MFEP. These strategies are simple and effective. For the former, it is more interesting. Because as we known, SHAKE algorithm was designed to handle the constraints in molecular dynamics in the past, has never been used in geometry optimization. Final applications on ALA dipeptide and 10-ALA peptide show that this combined optimization method works well. Use the information in SDP, the initial path could reach the more optimal MFEP. So more accurate free energies could be obtained and the amount of computation time could be saved.
Domain non-reciprocity of electromagnetic waves in a centrosymmetric TbMnO3
Authors: Chupis I. E.
Published: April 2013

The polariton spectrum in a centrosymmetric TbMnO3 is considered at low temperatures in a commensurate antiferromagnetic state after the spin-flop transition in a magnetic field. It is shown that a linear dependence of the electric polarization P on a magnetic field H, observed in this state, is caused by ordering spins of the terbium ions. The magnetoelectric energy PGH (G is the antiferromagnetic vector of terbium) induces in a centrosymmetric TbMnO3 without a linear magnetoelectric effect the non-reciprocal spectrum of TM and TE polaritons. In antiferromagnetic 180° terbium domains, the speed of electromagnetic waves turns out to be different, and directions of the electric field precession and the polarization plane rotation have opposite signs. The order of these effects were found to be 10−3.
Predicting crystals of Janus colloids
Authors: Vissers Teun , Preisler Zdeněk , Smallenburg Frank , Dijkstra Marjolein , Sciortino Francesco
Published: April 2013

We present a numerical study on the phase diagram for a simple model of Janus colloids, including ordered and disordered structures. Using a range of techniques, we generate a set of crystal structures and investigate their relative stability field in the pressure-temperature and temperature-density planes by means of free-energy calculations and thermodynamic integration schemes. We find that despite the Janus colloids’ simple architecture, they form stable crystal structures with complicated bond-topologies on an underlying face-centered-cubic or hexagonal-close-packed lattice. In addition, we find a phase consisting of wrinkled bilayer sheets, competing with both the fluid and the crystal phases. We detect a metastable gas-liquid coexistence which displays a micellization-driven re-entrant behavior.
Functional understanding of solvent structure in GroEL cavity through dipole field analysis
Authors: Weber Jeffrey K. , Pande Vijay S.
Published: April 2013

Solvent plays a ubiquitous role in all biophysical phenomena. Yet, just how the molecular nature of water impacts processes in biology remains an important question. While one can simulate the behavior of water near biomolecules such as proteins, it is challenging to gauge the potential structural role solvent plays in mediating both kinetic and equilibrium processes. Here, we propose an analysis scheme for understanding the nature of solvent structure at a local level. We first calculate coarse-grained dipole vector fields for an explicitly solvated system simulated through molecular dynamics. We then analyze correlations between these vector fields to characterize water structure under biologically relevant conditions. In applying our method to the interior of the wild type chaperonin complex GroEL+ES, along with nine additional mutant GroEL complexes, we find that dipole field correlations are strongly related to chaperonin function.
A full implementation of the response iteration scheme for density functional calculations
Authors: Krotscheck Eckhard , Liebrecht Michael
Published: April 2013

We describe the implementation of the response algorithm for solving the Kohn–Sham equations and equations of similar structure that appear frequently in calculations of the structure of inhomogeneous many-body systems. The algorithm solves directly for the (spin) density. We have implemented the method for arbitrary geometries in a way that does not need the explicit calculation of unoccupied states. We apply the method to the two sample molecules C6H6 and C60, as well as to the metal clusters Mg30 and Na40. Starting from very rough guesses for the initial electron density, convergence is reached significantly faster than with previous update algorithms.
On the possibility of vortex creation in superfluid systems by crossed homogeneous magnetic and inhomogeneous electric fields
Authors: Shevchenko S. I.
Published: April 2013

In the article by Shevchenko and A. S. Rukin, Pis'ma v Zh. Eksp. Teor. Fiz. 90, 46 (2009), it has been found that quantized vortices in superfluid systems acquire a charge in a magnetic field. A compensating charge with the opposite sign on a surface of the system can be at a macroscopic distance apart from the charge of the vortex. It is shown that as a result the total energy of the vortex charge and the compensating charge can be negative in the presence of an inhomogeneous electric field, normal to a homogeneous magnetic field. The conditions under which this leads to the spontaneous emergence of quantized vortices in the system are found. A possibility to observe the effect in He II, Bose gases of alkali metals and systems with spatially indirect excitons is discussed.
Dynamics of electron temperature and the relaxation times of electron–phonon system of a metal film
Authors: Bezuglyĭ A. I. , Shklovskij V. A.
Published: April 2013

A nonlinear integro-differential dynamic equation for electron temperature Te has been obtained for the case of transient heating of a metal film at low temperatures. The equation describes the process of heat transfer from electrons to phonons and the exchange of phonons between the film and the substrate. The heating of the film by a low-power oscillating thermal source has been thoroughly considered. Within the framework of linear response, we have established a relation between the frequency dispersion of the amplitude of Te and the characteristic time of electron–phonon collisions (τe) as well as the mean phonon escape time from the film (τes). In the next (quadratic) order of the perturbation theory, we have obtained a dc correction to Te and demonstrated that its frequency dependence also contains information about the times τe and τes. The results have been extended to dirty metal films. Various possibilities of the experimental determination of the times τe and τes have been discussed.
Structure and vibrational spectra of gauche- and trans-conformers of ethanol: Nonempirical anharmonic calculations and FTIR spectra in argon matrices
Authors: Pitsevich G. A. , Doroshenko I. Yu. , Pogorelov V. Ye. , Sablinskas V. , Balevicius V.
Published: April 2013

Low-temperature infrared absorption spectra are obtained for ethanol isolated in an argon matrix at temperatures of 20–45 K range for ratios of the numbers of the molecules being studied to the numbers of matrix atoms of 1:1000 and 1:2000. A preliminary interpretation of the spectra is obtained on the basis of the temperature variations in the spectra and published data. The structure of the ethanol conformers, rotational constants, and internal rotation barriers of the methyl and hydroxyl groups are calculated in the B3LYP/cc-pVQZ approximation. The harmonic and anharmonic IR spectra of the gauche- and trans-conformers are calculated in the same approximation. The force fields of the two conformers and the distributions of the potential energy of the normal vibrations are calculated and compared for a general set of dependent coordinates. Anharmonicity effects are taken into account by introducing spectroscopic masses for the hydrogen atoms when calculating the normal vibrations in the harmonic approximation.
Cyclotron waves in a non-neutral plasma column
Authors: Dubin Daniel H. E.
Published: April 2013

A kinetic theory of linear electrostatic plasma waves with frequencies near the cyclotron frequency Ωcs of a given plasma species s is developed for a multispecies non-neutral plasma column with general radial density and electric field profiles. Terms in the perturbed distribution function up to O(1/Ωcs2) are kept, as are the effects of finite cyclotron radius rc up to O(rc2). At this order, the equilibrium distribution is not Maxwellian if the plasma temperature or rotation frequency is not uniform. For rc→0, the theory reproduces cold-fluid theory and predicts surface cyclotron waves propagating azimuthally. For finite rc, the wave equation predicts that the surface wave couples to radially and azimuthally propagating Bernstein waves, at locations where the wave frequency equals the local upper hybrid frequency. The equation also predicts a second set of Bernstein waves that do not couple to the surface wave, and therefore have no effect on the external potential. The wave equation is solved both numerically and analytically in the WKB approximation, and analytic dispersion relations for the waves are obtained. The theory predicts that both types of Bernstein wave are damped at resonances, which are locations where the Doppler-shifted wave frequency matches the local cyclotron frequency as seen in the rotating frame.
On the Weyl tensor classification in all dimensions and its relation with integrability properties
Authors: Batista Carlos
Published: April 2013

In this paper the Weyl tensor is used to define operators that act on the space of forms. These operators are shown to have interesting properties and are used to classify the Weyl tensor, the well-known Petrov classification emerging as a special case. Particularly, in the Euclidean signature this classification turns out to be really simple. Then it is shown that the integrability condition of maximally isotropic distributions can be described in terms of the invariance of certain subbundles under the action of these operators. Here it is also proved a new generalization of the Goldberg-Sachs theorem, valid in all even dimensions, stating that the existence of an integrable maximally isotropic distribution imposes restrictions on the optical matrix. Also the higher-dimensional versions of the self-dual manifolds are investigated. These topics can shed light on the integrability of Einstein's equation in higher dimensions.
Junction array carbon nanotube bolometer
Authors: Kozlov Mikhail E.
Published: April 2013

Vertically aligned arrays of multi-walled carbon nanotubes (MWNT forests) irradiated with low-intensity near-infrared laser exhibited bolometric response that became significant with decreasing temperature down from room to about 84 K. High responsivity of 42 V/W with signal bandwidth of about 2600 Hz was observed in the region with a surprisingly small temperature coefficient of resistance. This fact along with peculiar current dependences of material differential photoresistance can be explained by lifting Coulomb blockade in carbon nanotube junctions irradiated with light. A combination of significant bolometric response and nonlinear electrical transport are believed to be characteristic features of the nanostructured junction array system. Investigated material also revealed quite substantial noise with equivalent power of 3 * 10−6 WHz−½ that can be reduced by optimization of nanotube junction network in the forest structure.
Bistability suppression and precession mode switching under condition of bifurcation resonance
Authors: Shutyi A. M. , Sementsov D. I.
Published: April 2013

We describe the magnetization dynamics in a single-crystal film in the area of bifurcation resonance caused by being positioned between the two equilibrium magnetization states that are in close proximity to one another. It is shown that the dynamic bistability can be suppressed by an additional AC field and the precession mode can be selected by an adjustment of the AC field frequency. Multiple direct switching from one mode to another is obtained by varying the frequency of the additional field. Also, we report the state when the system becomes noise-sensitive, i.e., it performs regular switching between precession modes that are different in amplitude because of the presence of the additional noise signal.
Theoretical and experimental evidence of Fano-like resonances in simple monomode photonic circuits
Authors: Mouadili A. , El Boudouti E. H. , Soltani A. , Talbi A. , Akjouj A. , Djafari-Rouhani B.
Published: April 2013

A simple photonic device consisting of two dangling side resonators grafted at two sites on a waveguide is designed in order to obtain sharp resonant states inside the transmission gaps without introducing any defects in the structure. This results from an internal resonance of the structure when such a resonance is situated in the vicinity of a zero of transmission or placed between two zeros of transmission, the so-called Fano resonances. A general analytical expression for the transmission coefficient is given for various systems of this kind. The amplitude of the transmission is obtained following the Fano form. The full width at half maximum of the resonances as well as the asymmetric Fano parameter are discussed explicitly as function of the geometrical parameters of the system. In addition to the usual asymmetric Fano resonance, we show that this system may exhibit an electromagnetic induced transparency resonance as well as well as a particular case where such resonances collapse in the transmission coefficient. Also, we give a comparison between the phase of the determinant of the scattering matrix, the so-called Friedel phase, and the phase of the transmission amplitude. The analytical results are obtained by means of the Green's function method, whereas the experiments are carried out using coaxial cables in the radio-frequency regime. These results should have important consequences for designing integrated devices such as narrow-frequency optical or microwave filters and high-speed switches. This system is proposed as a simpler alternative to coupled-micoresonators.
Growth of tungsten nanoparticles in direct-current argon glow discharges
Authors: K. Kishor Kumar , Couëdel L. , Arnas C.
Published: April 2013

The growth of nanoparticles from the sputtering of a tungsten cathode in DC argon glow discharges is reported. The study was performed at fixed argon pressure and constant discharge current. The growth by successive agglomerations is evidenced. First, tungsten nanocrystallites agglomerate into primary particles, the most probable size of which being ∼30 nm. Primary particles of this size are observed for all plasma durations and always remain the most numerous in the discharge. Primary particles quickly agglomerate to form particles with size up to ∼150 nm. For short plasma duration, log-normal functions describe accurately the dust particle size distributions. On the contrary, for long discharge durations, a second hump appears in the distributions toward large particle sizes. In the meantime, the discharge voltage, electron density, and emission line intensities strongly evolve. Their evolutions can be divided in four separate phases and exhibit unusual distinctive features compared to earlier observations in discharges in which particles were growing. The evolution of the different parameters is explained by a competition between the surface state of the tungsten cathode and the influence of the growing nanoparticles. The differences with sputtering glow discharges and chemically active plasmas suggest that the nanoparticle growth and its influence on discharge parameters is system and material dependent.
Performance and emission evaluation of biodiesel fueled diesel engine abetted with exhaust gas recirculation and Ni coated catalytic converter
Authors: Subramaniam D. , Murugesan A. , Avinash A.
Published: April 2013

This article summarizes the results of a laboratory exertion to evaluate the performance and emission parameters of a single cylinder, water cooled, direct injection diesel engine with and without the aid of exhaust gas recirculation (EGR), as well as with and without the assistance of nickel coated catalytic converter. Neat diesel, ethyl esters of waste frying oil (B100), and its diesel blends (B20 and B40) were used as test fuels to assess the various engine operating parameters. Conjointly, in this work, the effects of emission characteristics by incorporating nickel coated catalytic converter along with 0%, 15%, and 20% of HOT EGR technique are elaborately discussed. Experimental results proved that the diesel engine operated up to B40 blends assisted by catalytic converter, and 15% EGR level showed an adequate reduction in oxides of nitrogen in the exhaust pipe. Also, EGR level up to 15% proved reasonable brake thermal efficiency and specific fuel consumption when the test engine operated up to B40 biodiesel-diesel blends.
Note: A variable temperature cell for spectroscopy of thin films
Authors: Brock-Nannestad T. , Nielsen C. B. , Bak H. Ø. , Pittelkow M.
Published: April 2013

We report the design and construction of a cell that enables precisely controlled measurement of UV/Vis spectra of thin films on transparent substrates at temperatures up to 800 K. The dimensions of the setup are accommodated by a standard Varian Cary 5E spectrophotometer allowing for widespread use in standard laboratory settings. The cell also fits in a Bio-Rad IR-spectrometer. The cell is constructed with an outer water cooled heat shield of aluminum and an inner sample holder with heating element, thermo-resistor and windows, made from nickel coated copper. The cell can operate both in air, and with an inert gas filling. We illustrate the utility of the cell by characterization of three commercially available near infrared absorbers that are commonly used for laser welding of plastics and are known to possess high thermal stability.
Broadband electron spin resonance from 500 MHz to 40 GHz using superconducting coplanar waveguides
Authors: Clauss Conrad , Bothner Daniel , Koelle Dieter , Kleiner Reinhold , Bogani Lapo , Scheffler Marc , Dressel Martin
Published: April 2013

We present non-conventional electron spin resonance (ESR) experiments based on microfabricated superconducting Nb thin film waveguides. A very broad frequency range, from 0.5 to 40 GHz, becomes accessible at low temperatures down to 1.6 K and in magnetic fields up to 1.4 T. This allows for an accurate inspection of the ESR absorption position in the frequency domain, in contrast to the more common observation as a function of magnetic field. We demonstrate the applicability of frequency-swept ESR on Cr3+ atoms in ruby as well as on organic radicals of the nitronyl-nitroxide family. Measurements between 1.6 and 30 K reveal a small frequency shift of the ESR and a resonance broadening below the critical temperature of Nb, which we both attribute to a modification of the magnetic field configuration due to the appearance of shielding supercurrents in the waveguide.
Thermal stability of piezoelectric coefficients in (Ba1−xCax)(Zr0.05Ti0.95)O3: A lead-free piezoelectric ceramic
Authors: Singh Gurvinderjit , Tiwari V. S. , Gupta P. K.
Published: April 2013

Temperature dependence of piezoelectric properties of calcium doped Ba(Zr0.05Ti0.95)O3 ceramic has been investigated. The piezoelectric coefficients k31, kp, and d31 show anomaly near orthorhombic to tetragonal and rhombohedral to orthorhombic phase transition temperatures. Above orthorhombic to tetragonal transition temperature, all the coefficients are decreasing gradually but a sharp drop is observed near tetragonal to cubic transition. A percentage variation of kp was calculated between temperature range of −20 to 70 °C. It shows a variation of 10%–25% of its values for all the compositions.
Communication: New approach for analysis of thermodiffusion coefficients in ternary mixtures
Authors: Mialdun Aliaksandr , Shevtsova Valentina
Published: April 2013

A new approach is proposed to cross-check conflicting measured values of the thermodiffusion coefficients in ternary mixtures. The results of recent measurements performed in ternary mixture of hydrocarbons 1,2,3,4-tetrahydronaphthalene, isobutylbenzene, and dodecane by thermogravitational column [P. Blanco, M. M. Bou-Ali, J. K. Platten, D. A. de Mezquia, J. A. Madariaga, and C. Santamaría, J. Chem. Phys. 132, 114506 (2010)10.1063/1.3354114] and optical beam deflection [A. Königer, H. Wunderlich, and W. Köhler, J. Chem. Phys. 132, 174506 (2010)10.1063/1.3421547] are critically analyzed. A way of matching them into a unique value is reported. The accuracy of the integrated value should significantly exceed that of the original results. Two diagnostics are required to determine thermodiffusion coefficients in ternary mixture, e.g., two different wavelengths or density and refractive index. It is shown that by attributing a reliability weight for each pair of diagnostics among the available techniques the best combination can be selected. The true values of thermodiffusion coefficients are extremely sensitive to the knowledge of precise values of mass diffusion coefficients and contrast factors.
Local-structure origins of the sustained Curie temperature in (Ba,Ca)TiO3 ferroelectrics
Authors: Levin Igor , Krayzman Victor , Woicik Joseph C.
Published: April 2013

While the lattice volume in the solid-solution Ba1−xCaxTiO3 decreases with increasing x, the Curie temperature remains unaffected, in contrast to Ba1−xSrxTiO3. We have determined the origin of this phenomenon by comparing the local structures in (Ba,Ca)TiO3 and (Ba,Sr)TiO3. Reverse Monte Carlo refinements of instantaneous atomic positions using simultaneous fitting of multiple types of experimental data (neutron total scattering, X-ray absorption fine structure, patterns of diffuse scattering in electron diffraction) reveal both ferroelectric Ca displacements and their amplification of the Ti off-centering, which mitigate the lattice-volume effects. The activity of Ca is triggered by the anomalously strained Ca-O bonds.
Achieving saturation in vertical organic transistors for organic light-emitting diode driving by nanorod channel geometric control
Authors: Li Chang-Hung , Stehlin Fabrice , Wang Kai-Ruei , Lin Yu-Hsin , Wieder Fernand , Soppera Olivier , Zan Hsiao-Wen , Meng Hsin-Fei
Published: April 2013

When conventional field-effect transistors with short channel length suffer from non-saturated output characteristics, this work proposed a vertical channel transistor to operate like a solid-state vacuum tube and exhibit good saturated curves. We utilized deep ultra-violet interference lithography to produce ordered grid-like metal to control the potential profile in vertical channel. We compared experimental and simulated characteristics to investigate the keys to achieve saturation. Finally, with an optimized design, a vertical organic transistor is used to drive a solution-processed white-light organic light-emitting diode to perform a luminescence control (0–260 cd/m2) with a 3.3-V base potential swing.
Hot carrier-induced emission from the InGaN/GaN light-emitting diode by characterizing reverse-bias electroluminescence
Authors: Chen Hsiang
Published: April 2013

Reverse-bias operations can test the robustness and screen the weaknesses of the light emitting diode device for a shorter period of several hours. The mechanism of the hot carrier-induced emission, which is distinct from the yellow luminescence and the band-to-band recombination, has been confirmed by electroluminescence observations and hot carrier-induced equation. Furthermore, the degradation of electrical properties and failure of the device have been confirmed by the reverse-bias constant-current and constant-voltage stress. Focus ion beam, scanning electron microscopy, and energy dispersive X-ray spectroscopy reveal that deformed metal line might be a possible origin of reverse-bias luminescence because of high electric field.
Radio-frequency amplification property of the MgO-based magnetic tunnel junction using field-induced ferromagnetic resonance
Authors: Konishi K. , Dixit D. K. , Tulapurkar A. A. , Miwa S. , Nozaki T. , Kubota H. , Fukushima A. , Yuasa S. , Suzuki Y.
Published: April 2013

The radio-frequency (RF) voltage amplification property of a tunnel magnetoresistance device driven by an RF external-magnetic-field-induced ferromagnetic resonance was studied. The proposed device consists of a magnetic tunnel junction and an electrically isolated coplanar waveguide. The input RF voltage applied to the waveguide can excite the resonant dynamics in the free layer magnetization, leading to the generation of an output RF voltage under a DC bias current. The dependences of the RF voltage gain on the static external magnetic field strength and angle were systematically investigated. The design principles for the enhancement of the gain factor are also discussed.
Quantum spin/valley Hall effect and topological insulator phase transitions in silicene
Authors: Tahir M. , Manchon A. , Sabeeh K. , Schwingenschlögl U.
Published: April 2013

We present a theoretical realization of quantum spin and quantum valley Hall effects in silicene. We show that combination of an electric field and intrinsic spin-orbit interaction leads to quantum phase transitions at the charge neutrality point. This phase transition from a two dimensional topological insulator to a trivial insulating state is accompanied by a quenching of the quantum spin Hall effect and the onset of a quantum valley Hall effect, providing a tool to experimentally tune the topological state of silicene. In contrast to graphene and other conventional topological insulators, the proposed effects in silicene are accessible to experiments.
Scanning moiré fringe imaging for quantitative strain mapping in semiconductor devices
Authors: Kim Suhyun , Lee Sungho , Oshima Yoshifumi , Kondo Yukihito , Okunishi Eiji , Endo Noriaki , Jung Jaeryong , Byun Gwangsun , Lee Sunyoung , Lee Kyupil
Published: April 2013

The development of a method for the precise measurement of strain fields in semiconductor devices has become a critical requirement because the electrical performances of the devices are greatly influenced by the strain induced in their structures. We applied scanning moiré fringe imaging to demonstrate the quantitative strain mapping of a Si/Si1−xGex interfacial layer. The strain field was measured at a nano-meter scale spatial resolution, with a detection precision of 0.1%. The maximum value of the strain was measured to be 1.1% ± 0.1%, which is consistent with the direct measurement by high-resolution scanning transmission electron microscopy image.
Improvement of γ-ray energy resolution of LaBr3:Ce3+ scintillation detectors by Sr2+ and Ca2+ co-doping
Authors: Alekhin M. S. , de Haas J. T. M. , Khodyuk I. V. , Krämer K. W. , Menge P. R. , Ouspenski V. , Dorenbos P.
Published: April 2013

Commercially available LaBr3:5% Ce3+ scintillators show with photomultiplier tube readout about 2.7% energy resolution for the detection of 662 keV γ-rays. Here we will show that by co-doping LaBr3:Ce3+ with Sr2+ or Ca2+ the resolution is improved to 2.0%. Such an improvement is attributed to a strong reduction of the scintillation light losses that are due to radiationless recombination of free electrons and holes during the earliest stages (1–10 ps) inside the high free charge carrier density parts of the ionization track.
Blue single photon emission up to 200 K from an InGaN quantum dot in AlGaN nanowire
Authors: Deshpande Saniya , Das Ayan , Bhattacharya Pallab
Published: April 2013

We demonstrate polarized blue single photon emission up to 200 K from an In0.2Ga0.8N quantum dot in a single Al0.1Ga0.9N nanowire. The InGaN/AlGaN dot-in-nanowire heterostructure was grown on (111) silicon by plasma assisted molecular beam epitaxy. Nanowires dispersed on a silicon substrate show sharp exciton and biexciton transitions in the micro-photoluminescence spectra. Second-order correlation measurements performed under pulsed excitation at the biexciton wavelength confirm single photon emission, with a g(2)(0) of 0.43 at 200 K. The emitted photons have a short radiative lifetime of 0.7 ns and are linearly polarized along the c-axis of the nanowire with a degree of polarization of 78%.
Slow-sound photoacoustic microscopy
Authors: Zhang Chi , Zhou Yong , Li Chiye , Wang Lihong V.
Published: April 2013

We propose to enhance the axial resolution of photoacoustic microscopy (PAM) by reducing the speed of sound within the imaging region of interest. With silicone oil immersion, we have achieved a finest axial resolution of 5.8 μm for PAM, as validated by phantom experiments. The axial resolution was also enhanced in vivo when mouse ears injected with silicone oil were imaged. When tissue-compatible low-speed liquid becomes available, this approach may find broad applications in PAM as well as in other imaging modalities, such as photoacoustic computed tomography and ultrasound imaging.
Johnson and shot noises in intersubband detectors
Authors: Delga A. , Doyennette L. , Carras M. , Trinité V. , Bois P.
Published: April 2013

Johnson and shot noises are usually considered as independent in intersubband detectors. In this paper, we discuss some simple ideas showing that they are actually the equilibrium and far from equilibrium limits of a single phenomenon. We present an intuitive framework to consistently understand and model these noises in unipolar detectors, in order to enlarge the toolbox of quantum designers.
InAs/GaAs quantum dot solar cell with an AlAs cap layer
Authors: Tutu F. K. , Lam P. , Wu J. , Miyashita N. , Okada Y. , Lee K.-H. , Ekins-Daukes N. J. , Wilson J. , Liu H.
Published: April 2013

We report the effects of the deposition of an AlAs cap layer (CL) over InAs quantum dots (QDs) on the performance of QD solar cells (QDSCs). The growth of AlAs CL over InAs QDs led to the elimination of the wetting layer absorption and hence the enhancement of the open-current voltage, Voc, of a 20-layer InAs/GaAs QDSC from 0.69 V to 0.79 V. Despite a slight reduction in short-circuit current, Jsc, for the QDSC with AlAs CL, the enhancement of the Voc is enough to ensure that its efficiency is higher than the QDSC without AlAs CL.
Design and free-space measurements of a simple electromagnetic cloak for conducting cylindrical objects
Authors: Alitalo Pekka , Valagiannopoulos Constantinos A. , Culhaoglu Ali E.
Published: April 2013

In this work, we demonstrate experimentally with bistatic microwave measurements the effective cloaking of a long conducting (metallic) cylinder. The device that enables this cloaking effect is –unlike most known cloaks – a very simple structure composed of two conventional dielectric materials. Both materials are isotropic and homogeneous and have the relative permittivity larger than unity. The device design is carried out with an analytical model and is validated numerically. The cloaking effect of the realized cloak is characterized by measuring the bistatic scattering patterns of uncloaked and cloaked objects in free space and then comparing these with each other.
Study of sintered Nd-Fe-B magnet with high performance of Hcj (kOe) + (BH)max (MGOe) > 75
Authors: Hu Bo-Ping , Niu E. , Zhao Yu-Gang , Chen Guo-An , Chen Zhi-An , Jin Guo-Shun , Zhang Jin , Rao Xiao-Lei , Wang Zhen-Xi
Published: April 2013

We have developed a Nd-Fe-B sintered magnet of extremely high performance. The intrinsic coercivity Hcj is as high as 35.2 kOe (2803kA/m) together with the maximum energy product (BH)max of 40.4 MGOe (321.6kJ/m3). These values result in Hcj (kOe) + (BH)max (MGOe) > 75. Between 293 K (20ºC) and 473 K (200ºC), the temperature coefficients of remanence and intrinsic coercivity are αBr = −0.122 %/°C and αHcj = −0.403%/°C, respectively. A maximum operating temperature of 503 K (230ºC) is obtained when permeance coefficient Pc = −B/H = 2. Grain boundary diffusion (GBD) technique on magnet surface has been developed to increase Hcj by 3.6 kOe without significantly decrease of Br and (BH)max. The intrinsic coercivity of the GBD treated magnet Hcj(C) has a linear relationship with that of the untreated magnet Hcj(B) between 200 K and 473 K (in unit of kOe): Hcj(C) = 1.03Hcj(B) + 2.38. The enhancement of Hcj by GBD treatment has contributions not only from the improvement of microstructure but also from the increase of Ha in the grain surface layer. It is also found that GBD treatment brings no deterioration in corrosion resistance of untreated magnet.
The Boldface Illusion: A New Visual Assimilation
Authors: Fujimoto Kiyoshi
Published: April 2013

This article introduces a new visual illusion. A thick line induces boldface appearance to adjacent letters or geometric figures. This boldface illusion suggests that visual features assimilate in terms of thickness.
New handbook for standardised measurement of plant functional traits worldwide
Authors: Pérez-Harguindeguy N. , Díaz S. , Garnier E. , Lavorel S. , Poorter H. , Jaureguiberry P. , Bret-Harte M. S. , Cornwell W. K. , Craine J. M. , Gurvich D. E. , Urcelay C. , Veneklaas E. J. , Reich P. B. , Poorter L. , Wright I. J. , Ray P. , Enrico L. , Pausas J. G. , de Vos A. C. , Buchmann N. , Funes G. , Quétier F. , Hodgson J. G. , Thompson K. , Morgan H. D. , ter Steege H. , Sack L. , Blonder B. , Poschlod P. , Vaieretti M. V. , Conti G. , Staver A. C. , Aquino S. , Cornelissen J. H. C.
Published: April 2013

Plant functional traits are the features (morphological, physiological, phenological) that represent ecological strategies and determine how plants respond to environmental factors, affect other trophic levels and influence ecosystem properties. Variation in plant functional traits, and trait syndromes, has proven useful for tackling many important ecological questions at a range of scales, giving rise to a demand for standardised ways to measure ecologically meaningful plant traits. This line of research has been among the most fruitful avenues for understanding ecological and evolutionary patterns and processes. It also has the potential both to build a predictive set of local, regional and global relationships between plants and environment and to quantify a wide range of natural and human-driven processes, including changes in biodiversity, the impacts of species invasions, alterations in biogeochemical processes and vegetation–atmosphere interactions. The importance of these topics dictates the urgent need for more and better data, and increases the value of standardised protocols for quantifying trait variation of different species, in particular for traits with power to predict plant- and ecosystem-level processes, and for traits that can be measured relatively easily. Updated and expanded from the widely used previous version, this handbook retains the focus on clearly presented, widely applicable, step-by-step recipes, with a minimum of text on theory, and not only includes updated methods for the traits previously covered, but also introduces many new protocols for further traits. This new handbook has a better balance between whole-plant traits, leaf traits, root and stem traits and regenerative traits, and puts particular emphasis on traits important for predicting species’ effects on key ecosystem properties. We hope this new handbook becomes a standard companion in local and global efforts to learn about the responses and impacts of different plant species with respect to environmental changes in the present, past and future.