bluuebunny/crossref_metadata_2025 huggingface dataset:
Composition and hydrophilicity control of Mn-doped ferrite (MnxFe3−xO4) nanoparticles induced by polyol differentiation
Authors: Vamvakidis Kosmas , Katsikini Maria , Vourlias George , Angelakeris Mavroeidis , Paloura Eleni C. , Dendrinou-Samara Catherine
Published: February 2015

Hydrophilic Mn-doped ferrite nanoparticles (MnxFe3−xO4, x = 0.29–0.77) stabilized by PEG8000, PG and TEG & PG.
Structural and bonding patterns in gold clusters
Authors: Mingos D. Michael P.
Published: February 2015

The structures of phosphine and thiolato- clusters of gold are summarised and a theoretical model which unites the broad structural properties is presented.
Triboelectric effect as a new strategy for sealing and controlling the flow in paper-based devices
Authors: da Silva Everson T. S. G. , Santhiago Murilo , de Souza Fabrício R. , Coltro Wendell K. T. , Kubota Lauro T.
Published: February 2015

We reported here for the first time that triboelectric charges on PET sheets can be used to seal and control the flow rate in paper-based devices. The proposed method exhibits simplicity and low cost, provides reversible sealing and minimizes the effect of sample evaporation.
Non-exponential resistive switching in Ag2S memristors: a key to nanometer-scale non-volatile memory devices
Authors: Gubicza Agnes , Csontos Miklós , Halbritter András , Mihály György
Published: February 2015

The non-exponential dynamics of resistive switchings in Ag2S memristive nanojunctions provides an ideal basis for non-volatile memory applications.
Palladium-catalyzed direct arylation of phenols with aryl iodides
Authors: Long Rongrong , Yan Xufei , Wu Zhiqing , Li Zhengkai , Xiang Haifeng , Zhou Xiangge
Published: February 2015

An efficient protocol of palladium-catalyzed direct para-arylation of unfunctionalized phenols with aryl iodides under mild conditions was reported.
Polymerization of 5-alkyl δ-lactones catalyzed by diphenyl phosphate and their sequential organocatalytic polymerization with monosubstituted epoxides
Authors: Zhao Junpeng , Hadjichristidis Nikos
Published: February 2015

One-pot sequential organocatalytic polymerization reactions of 5-alkyl δ-lactones and monosubstituted epoxides were carried out using the base→acid “catalyst switch” strategy, leading to well-defined polyether–polyester block copolymers with various alkyl substituents.
Functionalization of photochromic dithienylmaleimides
Authors: Wutz D. , Falenczyk C. , Kuzmanovic N. , König B.
Published: February 2015

Synthetic routes for the functionalization of photochromic dithienylmaleimides at three different positions are reported.
Structure-induced catalytic activity of Co–Zn double-metal cyanide complexes for terpolymerization of propylene oxide, cyclohexene oxide and CO2
Authors: Sebastian Joby , Darbha Srinivas
Published: February 2015

Co–Zn DMC having monoclinic/rhombohedral structure were superior to the cubic complex for terpolymerization of propylene oxide, cyclohexene oxide and CO2.
Electron-deficient acene-based liquid crystals: dialkoxydicyanopyrazinoquinoxalines
Authors: Takeda Takashi , Tsutsumi Jun'ya , Hasegawa Tatsuo , Noro Shin-ichiro , Nakamura Takayoshi , Akutagawa Tomoyuki
Published: February 2015

Dialkoxydicyanopyrazinoquinoxaline exhibited liquid crystallinity, which was cooperatively stabilized by three noncovalent interactions, i.e. hydrophobic interaction, dipole–dipole interaction and π–π interaction.
Signalling mechanisms regulating phenotypic changes in breast cancer cells
Authors: Volinsky Natalia , McCarthy Cormac J. , von Kriegsheim Alex , Saban Nina , Okada-Hatakeyama Mariko , Kolch Walter , Kholodenko Boris N.
Published: February 2015

In MCF-7 breast cancer cells epidermal growth factor (EGF) induces cell proliferation, whereas heregulin (HRG)/neuregulin (NRG) induces irreversible phenotypic changes accompanied by lipid accumulation. Although these changes in breast cancer cells resemble processes that take place in the tissue, there is no understanding of signalling mechanisms regulating it. To identify molecular mechanisms mediating this cell-fate decision process, we applied different perturbations to pathways activated by these growth factors. The results demonstrate that phosphoinositide 3 (PI3) kinase (PI3K) and mammalian target of rapamycin (mTOR) complex (mTORC)1 activation is necessary for lipid accumulation that can also be induced by insulin, whereas stimulation of the extracellular-signal-regulated kinase (ERK) pathway is surprisingly dispensable. Interestingly, insulin exposure, as short as 4 h, was sufficient for triggering the lipid accumulation, whereas much longer treatment with HRG was required for achieving similar cellular response. Further, activation patterns of ATP citrate lyase (ACLY), an enzyme playing a central role in linking glycolytic and lipogenic pathways, suggest that lipids accumulated within cells are produced de novo rather than absorbed from the environment. In the present study, we demonstrate that PI3K pathway regulates phenotypic changes in breast cancer cells, whereas signal intensity and duration is crucial for cell fate decisions and commitment. Our findings reveal that MCF-7 cell fate decisions are controlled by a network of positive and negative regulators of both signalling and metabolic pathways.
Operational reliability assessment of power systems based on bus voltage
Authors: Qin Wenping , Song Jiancheng , Han Xiaoqing , Wang Peng
Published: February 2015

Bus voltage is a direct reliability indicator of a transmission network because it is related to system reactive and active power balance especially during a contingency state. This study proposes a technique to evaluate network operational reliability based on bus voltage. Two new voltage related bus reliability indices are proposed to represent bus reliability. Network reliability levels under various operating conditions and contingency states are evaluated and presented by probabilities of system voltage being in normal, under‐voltage, critical and collapse zones. The probabilistic voltage margin to the collapse point for each bus is evaluated to provide information for system operator regarding the risk under system random failures and load uncertainty. The IEEE 30‐bus system and a practical 220 kV Taiyuan power system in Shanxi Province of China have been analysed to illustrate the proposed techniques.
Sufficient and necessary condition of sensitivity consistency in static equivalent methods
Authors: Yu Juan , Zhang Mian , Li Wenyuan , Yan Wei , Zhao Xia
Published: February 2015

Both power flow states and sensitivities between variables are important information in power system analysis and should be kept consistent before and after equivalence. The general sufficient and necessary condition for sensitivity consistency in equivalent methods is derived. Based on the proposed general condition, it is further derived that Thevenin equivalent method can keep sensitivity consistent before and after equivalence, whereas the specific preconditions for sensitivity consistency are required for the traditional Ward equivalent method and extended Ward equivalent method. These two Ward equivalent methods cannot meet the preconditions in general cases and may lead to significant errors. This conclusion is confirmed by simulation results of the IEEE 39‐bus system and an actual power system with 661 buses.
Statistical analysis of the velocity and scalar fields in reacting turbulent wall-jets
Authors: Pouransari Z. , Biferale L. , Johansson A. V.
Published: February 2015

The concept of local isotropy in a chemically reacting turbulent wall-jet flow is addressed using direct numerical simulation (DNS) data. Different DNS databases with isothermal and exothermic reactions are examined. The chemical reaction and heat release effects on the turbulent velocity, passive scalar, and reactive species fields are studied using their probability density functions (PDFs) and higher order moments for velocities and scalar fields, as well as their gradients. With the aid of the anisotropy invariant maps for the Reynolds stress tensor, the heat release effects on the anisotropy level at different wall-normal locations are evaluated and found to be most accentuated in the near-wall region. It is observed that the small-scale anisotropies are persistent both in the near-wall region and inside the jet flame. Two exothermic cases with different Damköhler numbers are examined and the comparison revealed that the Damköhler number effects are most dominant in the near-wall region, where the wall cooling effects are influential. In addition, with the aid of PDFs conditioned on the mixture fraction, the significance of the reactive scalar characteristics in the reaction zone is illustrated. We argue that the combined effects of strong intermittency and strong persistency of anisotropy at the small scales in the entire domain can affect mixing and ultimately the combustion characteristics of the reacting flow.
Picosecond solvation dynamics—A potential viewer of DMSO—Water binary mixtures
Authors: Banik Debasis , Kundu Niloy , Kuchlyan Jagannath , Roy Arpita , Banerjee Chiranjib , Ghosh Surajit , Sarkar Nilmoni
Published: February 2015

In this work, we have investigated the composition dependent anomalous behavior of dimethyl sulfoxide (DMSO)-water binary mixture by collecting the ultrafast solvent relaxation response around a well known solvation probe Coumarin 480 (C480) by using a femtosecond fluorescence up-conversion spectrometer. Recent molecular dynamics simulations have predicted two anomalous regions of DMSO-water binary mixture. Particularly, these studies encourage us to investigate the anomalies from experimental background. DMSO-water binary mixture has repeatedly given evidences of its dual anomalous nature in front of our systematic investigation through steady-state and time-resolved measurements. We have calculated average solvation times of C480 by two individual well-known methods, among them first one is spectral-reconstruction method and another one is single-wavelength measurement method. The results of both the methods roughly indicate that solvation time of C480 reaches maxima in the mole fraction of DMSO XD = 0.12–0.17 and XD = 0.27–0.35, respectively. Among them, the second region (XD = 0.27–0.35) is very common as most of the thermodynamic properties exhibit deviation in this range. Most probably, the anomalous solvation trend in this region is fully guided by the shear viscosity of the medium. However, the first region is the most interesting one. In this region due to formation of strongly hydrogen bonded 1DMSO:2H2O complexes, hydration around the probe C480 decreases, as a result of which solvation time increases.
Generalized gradient approximation exchange energy functional with correct asymptotic behavior of the corresponding potential
Authors: Carmona-Espíndola Javier , Gázquez José L. , Vela Alberto , Trickey S. B.
Published: February 2015

A new non-empirical exchange energy functional of the generalized gradient approximation (GGA) type, which gives an exchange potential with the correct asymptotic behavior, is developed and explored. In combination with the Perdew-Burke-Ernzerhof (PBE) correlation energy functional, the new CAP-PBE (CAP stands for correct asymptotic potential) exchange-correlation functional gives heats of formation, ionization potentials, electron affinities, proton affinities, binding energies of weakly interacting systems, barrier heights for hydrogen and non-hydrogen transfer reactions, bond distances, and harmonic frequencies on standard test sets that are fully competitive with those obtained from other GGA-type functionals that do not have the correct asymptotic exchange potential behavior. Distinct from them, the new functional provides important improvements in quantities dependent upon response functions, e.g., static and dynamic polarizabilities and hyperpolarizabilities. CAP combined with the Lee-Yang-Parr correlation functional gives roughly equivalent results. Consideration of the computed dynamical polarizabilities in the context of the broad spectrum of other properties considered tips the balance to the non-empirical CAP-PBE combination. Intriguingly, these improvements arise primarily from improvements in the highest occupied and lowest unoccupied molecular orbitals, and not from shifts in the associated eigenvalues. Those eigenvalues do not change dramatically with respect to eigenvalues from other GGA-type functionals that do not provide the correct asymptotic behavior of the potential. Unexpected behavior of the potential at intermediate distances from the nucleus explains this unexpected result and indicates a clear route for improvement.
Homogeneous heating of a sample space by a modified heating assembly in a belt-type high-pressure apparatus
Authors: Miyakawa M. , Taniguchi T.
Published: February 2015

To create homogeneous heating in the sample space in a belt-type high-pressure apparatus, modified heating assemblies under pressure of 2.5 GPa and temperature up to 1700 °C were examined. Counterbores (with several diameters) were made at both ends of a cylindrical graphite heater to suppress the temperature gradient along the cylindrical axis of the heater. Temperature distributions within the heaters were measured by thermocouples and geothermometers. Both sets of measurements revealed that the temperature distribution in the sample space (6.9 mm outside diameter/12 mm length) was homogenized (i.e., variation of less than 10 °C under heating at 1700 °C) by optimizing the heater shape.
HXeI and HXeH in Ar, Kr, and Xe matrices: Experiment and simulation
Authors: Zhu Cheng , Niimi Keisuke , Taketsugu Tetsuya , Tsuge Masashi , Nakayama Akira , Khriachtchev Leonid
Published: February 2015

Experimental and theoretical studies of HXeI and HXeH molecules in Ar, Kr, and Xe matrices are presented. HXeI exhibits the H–Xe stretching bands at 1238.0 and 1239.0 cm−1 in Ar and Kr matrices, respectively, that are blue-shifted from the HXeI band observed in a Xe matrix (1193 cm−1) by 45 and 46 cm−1. These shifts are larger than those observed previously for HXeCl (27 and 16 cm−1) and HXeBr (37 and 23 cm−1); thus, the matrix effect is stronger for less stable molecules. The results for HXeI are qualitatively different from all previous results on noble-gas hydrides with respect to the frequency order between Ar and Kr matrices. For previously studied HXeCl, HXeBr, and HXeCCH, the H–Xe stretching frequency is reliably (by >10 cm−1) higher in an Ar matrix than in a Kr matrix. In contrast, the H–Xe stretching frequency of HXeI in an Ar matrix is slightly lower than that in a Kr matrix. HXeH absorbs in Ar and Kr matrices at 1203.2 and 1192.1 cm−1 (the stronger band for a Kr matrix), respectively. These bands are blue-shifted from the stronger band of HXeH in a Xe matrix (1166 cm−1) by 37 and 26 cm−1, and this frequency order is the same as observed for HXeCl, HXeBr, and HXeCCH but different from HXeI. The present hybrid quantum-classical simulations successfully describe the main experimental findings. For HXeI in the 〈110〉 (double substitution) site, the order of the H–Xe stretching frequencies (ν(Xe) < ν(Ar) < ν(Kr)) is in accord with the experimental observations, and also the frequency shifts in Ar and Kr matrices from a Xe matrix are well predicted (30 and 34 cm−1). Both in the theory and experiment, the order of the H–Xe stretching frequencies differs from the case of HXeCl, which suggests the adequate theoretical description of the matrix effect. For HXeH in the 〈100〉 (single substitution) site, the order of the frequencies is ν(Xe) < ν(Kr) < ν(Ar), which also agrees with the experiments. The calculated frequency shifts for HXeH in Ar and Kr matrices with respect to a Xe matrix (36 and 23 cm−1) are in a good agreement with the experiments. The present calculations predict an increase of the H–Xe stretching frequencies in the noble-gas matrices with respect to vacuum.
Tuner and radiation shield for planar electron paramagnetic resonance microresonators
Authors: Narkowicz Ryszard , Suter Dieter
Published: February 2015

Planar microresonators provide a large boost of sensitivity for small samples. They can be manufactured lithographically to a wide range of target parameters. The coupler between the resonator and the microwave feedline can be integrated into this design. To optimize the coupling and to compensate manufacturing tolerances, it is sometimes desirable to have a tuning element available that can be adjusted when the resonator is connected to the spectrometer. This paper presents a simple design that allows one to bring undercoupled resonators into the condition for critical coupling. In addition, it also reduces radiation losses and thereby increases the quality factor and the sensitivity of the resonator.
Sustainable production of energy from microalgae: Review of culturing systems, economics, and modelling
Authors: Zhou Xinping , Yuan Shuo , Chen Ranchi , Ochieng Reccab M.
Published: February 2015

The first generation biofuels primarily produced from crops compete with other food crops for arable land and are recently susceptible as safe and reliable renewable energy resources. The second generation biofuels produced from non-food feedstocks, mainly being microalgae, have been paid increasing attention to. Compared to the first generation biofuels, there are some advantages for microalgae such as high productivity, less land use, low requirement of water quality, environmental use (for wastewater treatment and carbon dioxide (CO2) biomitigation), etc. This paper reviews the current status of the use of microalgae for sustainable production of biofuels and specifically addresses issues to do with culturing systems, processes, economics, and modelling. Open ponds and a variation of closed photobioreactor culturing systems were described in detail. The culture processes are introduced briefly. Techno-economic analyses and analyses of environmental effect mainly due to CO2 biomitigation are performed. Life cycle assessments and the model studies of microalgae production are also reviewed comprehensively in addition.
Complex basis functions revisited: Implementation with applications to carbon tetrafluoride and aromatic N-containing heterocycles within the static-exchange approximation
Authors: White Alec F. , Head-Gordon Martin , McCurdy C. William
Published: February 2015

The method of complex basis functions for computing positions and widths of molecular resonances is revisited. An open-ended and efficient implementation is described. The basis set requirements of the complex basis are investigated within the computationally inexpensive static-exchange approximation, and the results of this investigation lead to a hierarchy of basis sets for complex basis function calculations on small molecules. These basis sets are then applied in static-exchange calculations on some larger molecules with multiple low energy shape resonances: carbon tetrafluoride, benzene, pyridine, pyrimidine, pyrazine, and s-triazine. The results indicate that more sophisticated methods using complex basis functions are worth pursuing in the search for accurate and computationally feasible methods for computing resonance energies in molecular systems.
Dynamic control of metastable remanent states in mesoscale magnetic elements
Authors: Ding J. , Jain S. , Pearson J. E. , Lendinez S. , Khovaylo V. , Novosad V.
Published: February 2015

The formation of the vortex-antivortex-vortex (v-av-v) metastable remanent states in elongated magnetic elements have been systematically investigated using micromagnetic modeling. It is demonstrated that the v-av-v magnetization pattern can be effectively stabilized by exciting the single vortex state with an external RF field. Furthermore, we show that a set of different polarity combinations of the vortex cores can be achieved by adjusting the frequency and amplitude of the excitation field. The corresponding dynamic response in time- and frequency-domain has also been presented. Owing to the diversity of the collective modes with different vortex-antivortex combinations, this system may open promising perspectives in the area of spin transfer torque oscillators.
Great enhancement of energy harvesting properties of piezoelectric/magnet composites by the employment of magnetic concentrator
Authors: Han Jinchi , Hu Jun , Wang Shan X. , He Jinliang
Published: February 2015

Wireless sensors capable of scavenging energy from ambient environment have been increasingly attractive for their outstanding merits of self-sufficient and maintenance-free. This paper presents a specific design of magnetic energy harvester based on a piezoelectric/magnet composite and a magnetic concentrator. With the employment of concentrator, the energy harvesting properties have been greatly improved, which is theoretically analyzed and experimentally demonstrated with the 35 times power enlargement. The fabricated prototype with a 3 cm air-gap concentrator harvests 326 μW power at 10 Arms, which enables sufficient and reliable power supply for a wide range of low-power sensors.
The thirty gigahertz instrument receiver for the Q-U-I Joint Tenerife experiment: Concept and experimental results
Authors: Villa Enrique , Cano Juan L. , Cagigas Jaime , Ortiz David , Casas Francisco J. , Pérez Ana R. , Aja Beatriz , Terán J. Vicente , de la Fuente Luisa , Artal Eduardo , Hoyland Roger , Mediavilla Ángel
Published: February 2015

This paper presents the analysis, design, and characterization of the thirty gigahertz instrument receiver developed for the Q-U-I Joint Tenerife experiment. The receiver is aimed to obtain polarization data of the cosmic microwave background radiation from the sky, obtaining the Q, U, and I Stokes parameters of the incoming signal simultaneously. A comprehensive analysis of the theory behind the proposed receiver is presented for a linearly polarized input signal, and the functionality tests have demonstrated adequate results in terms of Stokes parameters, which validate the concept of the receiver based on electronic phase switching.
Magnetism and transport properties of layered rare-earth cobaltates Ln0.3CoO2
Authors: Knížek K. , Novák P. , Jirák Z. , Hejtmánek J. , Maryško M. , Buršík J.
Published: February 2015

The ab-initio (GGA+U) electronic structure calculations of layered cobaltates Ln0.3CoO2 (Ln = La, Pr, Nd) prepared by ionic exchange from Na0.90CoO2 precursors have been performed. The data are used for numerical modeling of Seebeck coefficient within Boltzmann transport theory using BoltzTraP program [G. K. H. Madsen and D. J. Singh, Comput. Phys. Commun. 175, 67 (2006)], as well as for determination of the crystal field split levels of rare-earth ions using a method based on a transformation of Bloch states into the basis of Wannier functions [P. Novák et al., Phys. Rev. B 87, 205139 (2013)]. An overall agreement with observed magnetism and transport properties is obtained. In particular, the high p-type thermopower is well reproduced in a broad temperature range, but instead of theoretical linear decrease down to the lowest temperatures, the real systems exhibit an anomalous change of Seebeck sign, which might be related to the change of bare metallic carriers into the polaronic ones.
Liquid bulk rotation induced by electric field at free surface
Authors: Saghaei Tayebeh , Moradi Ali-Reza , Shirsavar Reza , Habibi Mehdi
Published: February 2015

In this paper, we induce rotation in a bulk of polar liquid with one free surface, by applying external crossed electric fields. We show that the induced rotation is due to the imposed stresses at the free surface of the liquid. A simple theoretical model was developed based on solving the Navier-Stokes equation that enables us to calculate the average induced stress in the liquid bulk, using experimental measurements of the angular velocity of the liquid. Our results indicate that the induced stresses and the angular velocities of the rotating liquid are independent from the electrical conductivity of the liquid. However, the induced stresses linearly depend on the external electric field and the applied electric voltage for passing the electric current through the bulk. Both experimental results and the theoretical model show that the angular velocity, linearly changes with depth.
Geometric scaling for a detonation wave governed by a pressure-dependent reaction rate and yielding confinement
Authors: Li J. , Mi X. , Higgins A. J.
Published: February 2015

The propagation of detonation waves in reactive media bounded by an inert, compressible layer is examined via computational simulations in two different geometries, axisymmetric cylinders, and two dimensional, planar slabs. For simplicity, an ideal gas equation of state is used with a pressure-dependent reaction rate that results in a detonation wave structure that does not exhibit cellular instability. The detonation is initiated as an ideal Chapman-Jouguet (CJ) detonation with a one-dimensional structure, and then allowed to propagate into a finite diameter or thickness layer of explosive surrounded by an inert layer. The yielding confinement of the inert layer results in the detonation wave decaying to a sub-CJ steady state velocity or failing entirely. Simulations are performed with different values of the reaction rate pressure exponent (n = 2 and 3) and different impedance confinement (greater than, less than, and equal to that of the explosive). The velocity decrement and critical dimension (critical diameter or thickness) are determined, and a 2:1 scaling between the cylinder diameter and slab thickness results is confirmed, in good agreement with curvature-based models of detonation propagation. The measured shock front curvature and detonation velocity relation (DN-κ) agrees with the classic model of Wood and Kirkwood. The computational simulations are compared to a simple, analytic model that treats the interaction of the confinement with the detonation products via Newtonian theory and a model that assumes a continuous variation in shock front curvature with the shock angle at the interface with the confinement matching the angle determined by shock polar analysis. The Newtonian model works very well for the case of high impedance confinement, while the shock front curvature model agrees with the simulations for the case of low impedance confinement.
Determining the cohesive energy of coronene by dispersion-corrected DFT methods: Periodic boundary conditions vs. molecular pairs
Authors: Sancho-García J. C. , Pérez-Jiménez A. J. , Olivier Y.
Published: February 2015

We investigate the cohesive energy of crystalline coronene by the dispersion-corrected methods DFT-D2, DFT-D3, and DFT-NL. For that purpose, we first employ bulk periodic boundary conditions and carefully analyze next all the interacting pairs of molecules within the crystalline structure. Our calculations reveal the nature and importance of the binding forces in every molecular pair tackled and provide revised estimates of the effects of two- and three-body terms, leading to accurate results in close agreement with experimental (sublimation enthalpies) reference values.
Patterned arrays of capped platinum nanowires with quasi-elastic mechanical response to lateral force
Authors: Hottes M. , Dassinger F. , Muench F. , Rauber M. , Stegmann C. , Schlaak H. F. , Ensinger W.
Published: February 2015

In this Letter, we describe the electrodeposition of capped, micro-sized Pt nanowire arrays in ion-track etched polymer templates and measure their collective mechanical response to an external force. By using an aperture mask during the irradiation process, it was possible to restrict the creation of pores in the templates to defined areas, allowing the fabrication of small nanowire arrays in different geometries and sizes. The simultaneous and highly reliable formation of many nanowire arrays was achieved using a pulsed electrodeposition technique. After deposition, the polymer matrix was removed using a gentle, dry oxygen plasma treatment, resulting in an excellent preservation of the array nanostructure as confirmed by scanning electron microscopy. A force measuring station was set up to perform mechanical characterization series on free-standing arrays. The nanowire arrays show a high robustness and respond sensitively to the applied force, making them attractive as spring elements in miniaturized inertial sensors, for example.
Investigation on the near-infrared-emitting thermal stability of Bi activated alkaline-earth aluminoborosilicate glasses
Authors: Wan Ronghua , Song Zhiguo , Li Yongjin , Zhou Yuting , Liu Qun , Qiu Jianbei , Yang Zhengwen , Yin Zhaoyi
Published: February 2015

Stability of near-infrared (NIR) emission form Bi doped 42.5SiO2-12.5B2O3-25Al2O3-20RO (SBAR, R = Ca, Sr, Ba) glasses under treatment between annealing and softening temperature were studied. Results show that the thermal stability of Bi-NIR-emitting centers in SBAR glasses generally decreases with the increase of the radius of modifier cations but is greatly higher that in similar alkali glasses. Comparative experiments indicate these phenomena can be understood by the tendency that the smaller and higher charged alkaline earth ions as higher field strength modifier cations will increase the concentration of negative charge on non-bridging oxygens and also help to stabilize the non-bridging oxygens, which can restrain the thermally activated diffusion and valence change of Bi-activated centers, respectively. The results can provide an improved understanding for the NIR-emitting thermal stability of Bi doped glasses and a scientific reference for composition design of Bi-doped optical fiber.
Enhancing the optical absorption of anthocyanins for dye-sensitized solar cells
Authors: Hemmatzadeh Reza , Jamali Abbas
Published: February 2015

This work presents our investigation on natural dyes extracted from the skin of Eggplant, Red Cabbage, and Red Onion as sensitizers for fabrication of dye-sensitized solar cells (DSSCs) and the conditions that could maximize their performance. We investigated the influence of various factors in the extraction process, such as various solvents, influence of acidification, or basification on the extraction solution, solution concentration on UV-VIS patterns absorption spectra of the anthocyanins, and the influence of these parameters on the performance of DSSCs. It was found that we could considerably enhance the optical absorptivity of natural sensitizers and consequently the performance of DSSCs. Overall performance of natural dyes as sensitizers in DSSCs was evaluated in terms of short circuit current and open circuit voltage. Short circuit photocurrent densities (JSC) up to 6.14 mA/cm2, and open circuit voltage (VOC) ranging from 0.29 to 0.66 V, were obtained from the natural sensitizers.
A new wind-farm parameterization for large-scale atmospheric models
Authors: Abkar Mahdi , Porté-Agel Fernando
Published: February 2015

In this article, a new model is developed to parameterize the effect of wind farms in large-scale atmospheric models such as weather models. In the new model, wind turbines in a wind farm are parameterized as elevated sinks of momentum and sources of turbulence. An analytical approach is used to estimate the turbine-induced forces as well as the turbulent kinetic energy (TKE) generated by the turbines inside the atmospheric boundary layer (ABL). In addition, the proposed model can take into account not only the effect of wind-farm density but also the effect of wind-farm layout and wind direction. The performance of the new model is tested with large-eddy simulations of ABL flows over very large wind farms with different turbine configurations. The results show that the new model is capable to accurately predict the turbine-induced forces as well as the TKE generated by the turbines inside the ABL.
Impact of carbon nanotube length on electron transport in aligned carbon nanotube networks
Authors: Lee Jeonyoon , Stein Itai Y. , Devoe Mackenzie E. , Lewis Diana J. , Lachman Noa , Kessler Seth S. , Buschhorn Samuel T. , Wardle Brian L.
Published: February 2015

Here, we quantify the electron transport properties of aligned carbon nanotube (CNT) networks as a function of the CNT length, where the electrical conductivities may be tuned by up to 10× with anisotropies exceeding 40%. Testing at elevated temperatures demonstrates that the aligned CNT networks have a negative temperature coefficient of resistance, and application of the fluctuation induced tunneling model leads to an activation energy of ≈14 meV for electron tunneling at the CNT-CNT junctions. Since the tunneling activation energy is shown to be independent of both CNT length and orientation, the variation in electron transport is attributed to the number of CNT-CNT junctions an electron must tunnel through during its percolated path, which is proportional to the morphology of the aligned CNT network.
Electronic modulations in a single wall carbon nanotube induced by the Au(111) surface reconstruction
Authors: Clair Sylvain , Shin Hyung-Joon , Kim Yousoo , Kawai Maki
Published: February 2015

The structural and electronic structure of single wall carbon nanotubes adsorbed on Au(111) has been investigated by low-temperature scanning tunneling microscopy and spectroscopy. The nanotubes were dry deposited in situ in ultrahigh vacuum onto a perfectly clean substrate. In some cases, the native herringbone reconstruction of the Au(111) surface interacted directly with adsorbed nanotubes and produced long-range periodic oscillations in their local density of states, corresponding to charge transfer modulations along the tube axis. This effect, however, was observed not systematically for all tubes and only for semiconducting tubes.
Non-thermal plasma mills bacteria: Scanning electron microscopy observations
Authors: Lunov O. , Churpita O. , Zablotskii V. , Deyneka I. G. , Meshkovskii I. K. , Jäger A. , Syková E. , Kubinová Š. , Dejneka A.
Published: February 2015

Non-thermal plasmas hold great promise for a variety of biomedical applications. To ensure safe clinical application of plasma, a rigorous analysis of plasma-induced effects on cell functions is required. Yet mechanisms of bacteria deactivation by non-thermal plasma remain largely unknown. We therefore analyzed the influence of low-temperature atmospheric plasma on Gram-positive and Gram-negative bacteria. Using scanning electron microscopy, we demonstrate that both Gram-positive and Gram-negative bacteria strains in a minute were completely destroyed by helium plasma. In contrast, mesenchymal stem cells (MSCs) were not affected by the same treatment. Furthermore, histopathological analysis of hematoxylin and eosin–stained rat skin sections from plasma–treated animals did not reveal any abnormalities in comparison to control ones. We discuss possible physical mechanisms leading to the shred of bacteria under non-thermal plasma irradiation. Our findings disclose how helium plasma destroys bacteria and demonstrates the safe use of plasma treatment for MSCs and skin cells, highlighting the favorability of plasma applications for chronic wound therapy.
Carbon nanotube-graphene junctions studied by impedance spectra
Authors: Gao M. , Huang Z. L. , Zeng B. , Pan T. S. , Zhang Y. , Peng H. B. , Lin Y.
Published: February 2015

Two kinds of carbon nanotube (CNT)-graphene structures, vertical CNT-graphene and paralleled CNT–graphene, were fabricated to investigate the geometrical effect on the transport properties of the CNT–graphene junctions by using AC impedance spectra. The results demonstrated that the geometrical structure showed obvious impact on the resistance rather than the capacity of the junction. It is proposed that the difference caused by the geometrical structure may be associated with the dangling bonds terminated by –OH or –COOH of the open-ended CNTs. The unsymmetrical chemical bonds will increase the dipole moment in CNTs, which enhance the interaction between vertical CNTs and graphene and reduce the contact resistance.
High power frequency comb based on mid-infrared quantum cascade laser at λ ∼ 9 μm
Authors: Lu Q. Y. , Razeghi M. , Slivken S. , Bandyopadhyay N. , Bai Y. , Zhou W. J. , Chen M. , Heydari D. , Haddadi A. , McClintock R. , Amanti M. , Sirtori C.
Published: February 2015

We investigate a frequency comb source based on a mid-infrared quantum cascade laser at λ ∼ 9 μm with high power output. A broad flat-top gain with near-zero group velocity dispersion has been engineered using a dual-core active region structure. This favors the locking of the dispersed Fabry-Pérot modes into equally spaced frequency lines via four wave mixing. A current range with a narrow intermode beating linewidth of 3 kHz is identified with a fast detector and spectrum analyzer. This range corresponds to a broad spectral coverage of 65 cm−1 and a high power output of 180 mW for ∼176 comb modes.
Atomic arrangement at ZnTe/CdSe interfaces determined by high resolution scanning transmission electron microscopy and atom probe tomography
Authors: Bonef Bastien , Gérard Lionel , Rouvière Jean-Luc , Grenier Adeline , Jouneau Pierre-Henri , Bellet-Amalric Edith , Mariette Henri , André Régis , Bougerol Catherine
Published: February 2015

High resolution scanning transmission electron microscopy and atom probe tomography experiments reveal the presence of an intermediate layer at the interface between two binary compounds with no common atom, namely, ZnTe and CdSe for samples grown by Molecular Beam Epitaxy under standard conditions. This thin transition layer, of the order of 1 to 3 atomic planes, contains typically one monolayer of ZnSe. Even if it occurs at each interface, the direct interface, i.e., ZnTe on CdSe, is sharper than the reverse one, where the ZnSe layer is likely surrounded by alloyed layers. On the other hand, a CdTe-like interface was never observed. This interface knowledge is crucial to properly design superlattices for optoelectronic applications and to master band-gap engineering.
Role of Fe impurity complexes in the degradation of GaN/AlGaN high-electron-mobility transistors
Authors: Puzyrev Y. S. , Schrimpf R. D. , Fleetwood D. M. , Pantelides S. T.
Published: February 2015

Recent experiments show that GaN/AlGaN high-electron-mobility transistors suffer from significant current collapse, which is caused by an increase in the concentration of traps with energy levels 0.5–0.6 eV below the conduction-band edge. This increase in trap concentration is consistent with thermally activated defect diffusion, but the responsible defect complexes have not been identified. It has been suggested that the defect complex may contain iron because of the proximity of the Fe-doped GaN substrate. Here, we report first-principles density-functional calculations of substitutional iron complexes, investigate their properties, and show that the FeGa-VN complex has properties that account for the observed degradation.
Geographic variation in long-term trajectories of change in coral recruitment: a global-to-local perspective
Authors: Edmunds P. J. , Steneck R. , Albright R. , Carpenter R. C. , Chui A. P. Y. , Fan T.-Y. , Harii S. , Kitano H. , Kurihara H. , Legendre L. , Mitarai S. , Muko S. , Nozawa Y. , Padilla-Gamino J. , Price N. N. , Sakai K. , Suzuki G. , van Oppen M. J. H. , Yarid A. , Gates R. D.
Published: February 2015

Compiled abundances of juvenile corals revealed no change over time in the Pacific, but a decline in the Caribbean. Using these analyses as a rationale, we explored recruitment and post-settlement success in determining coral cover using studies in the Caribbean (St John, Bonaire) and Pacific (Moorea, Okinawa). Juvenile corals, coral recruits, and coral cover have been censused in these locations for years, and the ratio of juvenile (J) to recruiting (R) corals was used to measure post-settlement success. In St John and Bonaire, coral cover was stable but different between studies, with the ratio of the density of juveniles to density of recruits (J:R) ~0.10; in Moorea, declines in coral cover were followed by recovery that was related to the density of juvenile corals 3 years before, with J:R ~0.40; and in Okinawa, a decline in coral cover in 1998 was followed by a slow recovery with J/R ~0.01. Coral cover was associated positively with juvenile corals in St John, and in Okinawa, the density of juvenile corals was associated positively with recruits the year before. J:R varied among studies, and standardised densities of juvenile corals declined in the Caribbean, but increased in the Pacific. These results suggest that differences in the post-settlement success may drive variation in coral community structure.
Novel mixed-linkage β-glucan activated by c-di-GMP in
Sinorhizobium meliloti
Authors: Pérez-Mendoza Daniel , Rodríguez-Carvajal Miguel Ángel , Romero-Jiménez Lorena , Farias Gabriela de Araujo , Lloret Javier , Gallegos María Trinidad , Sanjuán Juan
Published: February 2015

Significance

We report a novel linear mixed-linkage (1→3)(1→4)-β-glucan produced by the bacterium
Sinorhizobium meliloti
upon raising cyclic diguanylate (c-di-GMP) intracellular levels. This unique bacterial polysaccharide resembles (1→3)(1→4)-β-glucans found in cereals and certain lichens but has a distinctive primary structure. Genes, proteins, and regulatory pathways for producing this new polymer are described. Our findings open the possibility of using bacteria to produce (1→3)(1→4)-β-glucans, which are receiving increasing interest as bioactive compounds, and provide new elements to disclose molecular mechanisms of c-di-GMP regulation as well as for investigating the evolution, activity, and specificity of glycosyl transferases.
Translators’ voices in Norwegian retranslations of Bob Dylan’s songs
Authors: Greenall Annjo K.
Published: February 2015

This paper tackles several questions relating to the issue of the translator’s voice in retranslation: how do others’ voices (including other (re)translations) interact with the translator’s voice in the production of a translation? How does the intersubjectively constituted voice of the translator manifest itself in paratexts, in the translated text and, in the case of singer-translators, in the translator’s physical, performing voice? The case discussed is that of Bob Dylan in (re)translation into Norwegian, and it is concluded that different singer-translators involve others in the process in various ways and to varying degrees; that there are great subjective differences in how and to what extent they take other (re)translations of Dylan into account; and that they choose different strategies for displaying their voices in paratexts, texts and performances, differences that can be explained by reference to the singer-translator’s role and status on the cultural scene.
Dead heroes and living deserters: the Yugoslav People's Army and the public of Valjevo, Serbia, on the verge of war 1991
Authors: Lučić Robert
Published: February 2015

With the withdrawal of the Yugoslav People's Army from Slovenia, the Yugoslav conflict escalated into a full-scale war in Croatia in the summer of 1991. The article explores the involvement of the Yugoslav People's Army in the war in East Slavonia from the local perspective of the Serbian town of Valjevo. Touching upon Serbia's political and social radicalization in Valjevo in the second half of the 1980s, it discusses the process of the local garrison's military mobilization and an incidence of mass desertion by Valjevo reservists in September 1991. Based on local archive material, press releases, and interviews with former soldiers, the account focuses on the city's national engagement, the garrison's deployment in combat, and the process of “reimplanting” patriotism after the reservists' desertion. It reveals that the engagement of Valjevo's troops completed the city's mental process of ethnic segregation. The outbreak of violence in Croatia in 1991 destroyed the Yugoslav People's Army as a pillar of Yugoslav statehood and permanently transformed the identities of Valjevo's soldiers.
Depth and Artificial Reef Type Effects on Size and Distribution of Red Snapper in the Northern Gulf of Mexico
Authors: Jaxion-Harm J. , Szedlmayer S. T.
Published: February 2015

The Red Snapper Lutjanus campechanus is a highly exploited commercial and recreational species that dominates the artificial reef systems in the northern Gulf of Mexico. Off coastal Alabama there are few natural reefs, but in the last 50 years government programs and private fishers have placed numerous artificial reefs in the northeast Gulf of Mexico with the goal of increasing fisheries production. We examined the effects of artificial reef depth and reef type on Red Snapper densities and size distributions. We used hook-and-line, fish trap, and scuba visual surveys to estimate Red Snapper densities on four types of artificial reefs: army tanks, pyramids, small reefs (e.g., metal cages, pipelines), and large reefs (e.g., ships, dry docks, oil platforms). Small Red Snapper (<33 cm TL) were significantly more abundant at shallower depths (<35 m) and on small artificial reefs. Army tanks showed significantly more large fish (>33 cm TL) at shallow sites (<35 m) than at deeper sites (>35 m); in contrast, pyramids showed significantly more large fish at deeper sites. Ontogenetic habitat shift and fishing mortality were the most likely factors that would explain these Red Snapper distributions. Worldwide, artificial reefs are being used to enhance fishery resources and for habitat restoration. We document the importance of reef design and deployment location for Red Snapper, as well as the need for future artificial reef deployments to consider the relevant variables that affect the species that managers are attempting to enhance.

Received May 4, 2014; accepted October 20, 2014
Tragedy, comedy and history in On Revolution
Authors: Arese Laura
Published: February 2015

This article explores the role of tragedy and comedy as hermeneutic perspectives present in some passages of Hannah Arendt's thought. The first claim is that, as a hermeneutic device applied to the understanding of history, tragedy can be a key to interpreting On Revolution. The Aristotelian concept of mimesis and the characteristics of tragic theatre set out in Poetics are important sources of this approach. Secondly, the article examines the sardonic tone that Arendt uses at the end of the first chapter of On Revolution, where she accuses the protagonists of the bloodiest phase of the Russian Revolution of being the ‘fools of history’. Some suggestions are made regarding the meaning of this comedic key, which reappears, not coincidentally, in another of the philosopher's most important historical analyses: Eichmann in Jerusalem.
Reading Arendt in Tehran: on extraordinary democratic politics and the failure of revolutions
Authors: Rensmann Lars
Published: February 2015

This article seeks to understand the 2009 Iranian anti-government uprising through an Arendtian lens, and re-read Arendt's conceptions of power, civil disobedience and revolution in the light of this event. Generating non-institutionalized, non-regularized public spaces both within and beyond the limits of the established order, diverse communities reconstituted an Iranian multitude that temporarily shifted the power from the regime to the street. Arendt helps us understand both how this self-authorized and self-empowered multitude was able to recover democratic subjectivity and power under non-democratic conditions, and how the democratic uprising failed and the regime could crush it and consolidate its rule.