bluuebunny/crossref_metadata_2025 huggingface dataset:
Event‐based state estimation: an emulation‐based approach
Authors: Trimpe Sebastian
Published: January 2017

An event‐based state estimation approach for reducing communication in a networked control system is proposed. Multiple distributed sensor agents observe a dynamic process and sporadically transmit their measurements to estimator agents over a shared bus network. Local event‐triggering protocols ensure that data is transmitted only when necessary to meet a desired estimation accuracy. The event‐based design is shown to emulate the performance of a centralised state observer design up to guaranteed bounds, but with reduced communication. The stability results for state estimation are extended to the distributed control system that results when the local estimates are used for feedback control. Results from numerical simulations and hardware experiments illustrate the effectiveness of the proposed approach in reducing network communication.
Active disturbance attenuation control for permanent magnet synchronous motor via feedback domination and disturbance observer
Authors: Niu Xitong , Zhang Chuanlin , Li Hui
Published: January 2017

In this study, a novel active disturbance attenuation controller is investigated for the permanent magnet synchronous motor servo system by integrating a feedback domination technique and disturbance observer‐based control strategy. A disturbance observer is first constructed to enable an active estimation process of the mismatched disturbances. Second, the authors adopt a feedback domination technique, rather than popularly used feedback linearisation methods, to handle the system non‐linearities. A Lyapunov function‐based recursive design is then carried out to derive the composite controllers in an explicit way, while a semi‐global input‐to‐state stability can be guaranteed. The proposed methodology not only performs an improved closed‐loop control performance comparing to several existing results, but also renders a simple control law which will ease its practical implementations. Abundant comparison simulation results are provided to demonstrate the effectiveness of the proposed scheme.
Normalised normal constraint algorithm applied to multi‐objective security‐constrained optimal generation dispatch of large‐scale power systems with wind farms and pumped‐storage hydroelectric stations
Authors: Lin Shunjiang , Liu Mingbo , Li Qifeng , Lu Wentian , Yan Yuan , Liu Cuiping
Published: January 2017

A multi‐objective security‐constrained optimal generation dispatch (MOSCOGD) model for large‐scale power systems with wind farms and pumped‐storage hydroelectric (PSH) stations is proposed. In this model, fuel consumption, emission content of atmospheric pollutants, and power purchase costs are taken into account as objective functions, and network security under basic status and N  − 1 criterion conditions, and the operational limits of PSH resources are included in the constraints. The difficulties associated with discrete variables for describing the operational characteristics of PSH resources are avoided by introducing two continuous variables, generation power and pumping power, which satisfy complementary constraints. The normalised normal constraint algorithm is used to transform the three‐objective optimal dispatch model into a series of single‐objective optimisation models, which are solved by the interior point method, resulting in a series of evenly distributed Pareto optimal solutions (POSs) and the complete Pareto frontier surface. The computational efficiency is greatly enhanced by employing a checking–adding–checking again‐adding again scheme to address network security constraints. Moreover, parallel computing is employed to improve the computation speed for solving the POSs of the MOSCOGD model. Test results on an actual large‐scale power system and the modified IEEE 39‐bus system demonstrate the effectiveness of the proposed method.
Antenna pattern in three‐dimensional modelling of the arrival angle in simulation studies of wireless channels
Authors: Ziółkowski Cezary , Kelner Jan M.
Published: January 2017

The statistical properties of the received signal are significantly dependent on the direction of arrival at the receiving antenna. Therefore, knowledge of the arrival angles is useful in simulation studies of wireless channels. This study presents a method for determining the arrival angles and their intensity in the azimuth and elevation planes. Besides, the impact of the propagation environment and radiation pattern of the transmitting antenna on the scattering intensity of the arrival angles is shown. This significantly distinguishes the proposed technique from the methods for determining signal direction that have been previously described in the literature. The procedure is based on a geometric description of the scattering areas, which are a set of half‐ellipsoids. Their number and size result from the parameters of the power delay spectrum or profile for modelled propagation environment. Simulation studies offer the possibility of adapting the statistical properties of the arrival angles to the type of propagation environment examined. The inclusion of the propagation phenomena in the azimuth and elevation planes provides a better representation of the empirical results compared with two‐dimensional modelling. This fact is shown by a comparison of statistical properties between the simulated directions and the measurement results for selected types of propagation environments.
Predicting HCN, HCO+, multi-transition CO, and dust emission of star-forming galaxies
Authors: Vollmer B. , Gratier P. , Braine J. , Bot C.
Published: January 2017

High-zstar-forming galaxies have significantly higher gas fractions and star-formation efficiencies per molecular gas mass than local star-forming galaxies. In this work, we take a closer look at the gas content or fraction and the associated star-formation rate in main sequence and starburst galaxies atz= 0 andz~ 1–2 by applying an analytical model of galactic clumpy gas disks to samples of local spiral galaxies, ULIRGs, submillimeter (smm), and high-zstar-forming galaxies. The model simultaneously calculates the total gas mass, Hi/H2mass, the gas velocity dispersion, IR luminosity, IR spectral energy distribution, CO spectral line energy distribution (SLED), HCN(1–0) and HCO+(1–0) emission of a galaxy given its size, integrated star formation rate, stellar mass radial profile, rotation curve, and ToomreQparameter. The model reproduces the observed CO luminosities and SLEDs of all sample galaxies within the model uncertainties (~0.3 dex). Whereas the CO emission is robust against the variation of model parameters, the HCN and HCO+emissions are sensitive to the chemistry of the interstellar medium. The CO and HCN mass-to-light conversion factors, including CO-dark H2, are given and compared to the values found in the literature. All model conversion factors have uncertainties of a factor of two. Both the HCN and HCO+emissions trace the dense molecular gas to a factor of approximately two for the local spiral galaxies, ULIRGs and smm-galaxies. Approximately 80% of the molecular line emission of compact starburst galaxies originates in non-self-gravitating gas clouds. The effect of HCN infrared pumping is small but measurable (10–20%). The gas velocity dispersion varies significantly with the ToomreQparameter. TheQ= 1.5 model yields high-velocity dispersions (vdisp≫ 10 km s-1) consistent with available observations of high-zstar-forming galaxies and ULIRGs. However, we note that these high-velocity dispersions are not mandatory for starburst galaxies. The integrated Kennicutt-Schmidt law has a slope of approximately 1 for the local spirals, ULIRGs, and smm-galaxies, whereas the slope is 1.7 for high-zstar-forming galaxies. The model shows Kennicutt-Schmidt laws with respect to the molecular gas surface density with slopes of approximately 1.5 for local spiral galaxies, high-zstar-forming galaxies. The relation steepens for compact starburst galaxies. The model star-formation rate per unit area is, as observed, proportional to the molecular gas surface density divided by the dynamical timescale. Our relatively simple analytic model together with the recipes for the molecular line emission appears to capture the essential physics of galactic clumpy gas disks.
Vector bright soliton behaviors of the coupled higher-order nonlinear Schrödinger system in the birefringent or two-mode fiber
Authors: Liu Lei , Tian Bo , Xie Xi-Yang , Guan Yue-Yang
Published: January 2017

Studied in this paper are the vector bright solitons of the coupled higher-order nonlinear Schrödinger system, which describes the simultaneous propagation of two ultrashort pulses in the birefringent or two-mode fiber. With the help of auxiliary functions, we obtain the bilinear forms and construct the vector bright one- and two-soliton solutions via the Hirota method and symbolic computation. Two types of vector solitons are derived. Single-hump, double-hump, and flat-top solitons are displayed. Elastic and inelastic interactions between the Type-I solitons, between the Type-II solitons, and between the two combined types of the solitons are revealed, respectively. Especially, from the interaction between a Type-I soliton and a Type-II soliton, we see that the Type-II soliton exhibits the oscillation periodically before such an interaction and becomes the double-hump soliton after the interaction, which is different from the previously reported.
Modelling of direct ultraviolet photoionization and charge recombination of aerosol nanoparticles in continuous flow
Authors: Nishida R. T. , Boies A. M. , Hochgreb S.
Published: January 2017

Ultrafine aerosol particles are electrically charged in a range of devices to enable their detection, capture, and control. Direct ultraviolet (UV) photoionization enables increased charging of some nanoparticle materials over alternative charging mechanisms such as diffusion charging, particularly in size ranges below 50 nm diameter. The aim of this work is to provide modelling and simulation of ion and particle charge and discharge processes and transport and collection in a continuous flow. A non-dimensional analysis indicates regimes under which the photocharging process is dominated by diffusion, electric field transport, convection, photoionization, or recombination. The computational fluid dynamics (CFD) model developed in this work is the first to include UV photoionization and detailed ion and particle recombination theory. The validity of assumptions made for diffusional wall losses and external electric field action is evaluated by comparison with 0D Numerical and 3D CFD models. Regimes are identified to distinguish the level of details required for aerosol transport and charging models.
Effect of off-cut angle of hydrogen-terminated diamond(111) substrate on the quality of AlN towards high-density AlN/diamond(111) interface hole channel
Authors: Imura Masataka , Banal Ryan G. , Liao Meiyong , Liu Jiangwei , Aizawa Takashi , Tanaka Akihiro , Iwai Hideo , Mano Takaaki , Koide Yasuo
Published: January 2017

Single-crystal AlN/diamond heterojunction with high-density interface hole channel is successfully obtained by metal-organic vapor phase epitaxy. The AlN layer is epitaxially grown on hydrogen-terminated (H-)diamond(111) substrate. The thermal treatment of diamond substrate just before AlN growth under hydrogen and ammonia mixture environment at 1250 °C leads to surface sheet hole density as high as ∼1.0 × 1014 cm−2 without structural reconstruction of diamond surface. In addition, the use of smaller off-cut angle (0.20 ± 0.25°) H-diamond(111) substrate combined with this treatment enables to obtain single-crystal epitaxial AlN layer, which simultaneously acts as passivation of the surface hole channel with such a high density. The AlN/H-diamond(111) heterojunction reveals type-II staggered energy band configuration with valence band offset of ∼2.0 eV, which is suitable for the fabrication of p-channel field-effect transistor using AlN-gate-insulator/diamond heterojunction. These results are promising for the development of AlN/diamond hybrid power electronic devices.
Quasilinear theory of quantum Fermi liquid
Authors: Tsintsadze Nodar L. , Alkhanishvili Davit M.
Published: January 2017

Quasilinear theory of a weakly turbulent quantum Fermi liquid is presented. Landau's linear theory of Fermi liquids is generalized by consideration of weak nonlinear regime. A newly derived kinetic equation of the Fermi particles is used to derive a slowly varying distribution function f0, which satisfies the diffusion equation. It is shown that the magnitude of the diffusion coefficient D depends on weak interactions between atoms and the de Broglie waves diffraction.
Valence fluctuations in Sn(Pb)2P2S6 ferroelectrics
Authors: Yevych R. , Haborets V. , Medulych M. , Molnar A. , Kohutych A. , Dziaugys A. , Banys Ju. , Vysochanskii Yu.
Published: January 2017

The valence fluctuations which are related to the charge disproportionation of phosphorous ions P4++P4+→P3++P+5 are the origin of ferroelectric and quantum paraelectric states in Sn(Pb)2P2S6 semiconductors. They involve recharging of SnPS3 or PbPS3 structural groups which can be represented as half-filled sites in the crystal lattice. Temperature–pressure phase diagram for Sn2P2S6 compound and temperature-composition phase diagram for (PbySn1–y)2P2S6 mixed crystals, which include tricritical points and where a temperature of phase transitions decrease to 0 K, together with the data about some softening of low energy optic phonons and rise of dielectric susceptibility at cooling in quantum paraelectric state of Pb2P2S6 are analyzed by GGA electron and phonon calculations and compared with electronic correlations models. The anharmonic quantum oscillators model is developed for description of phase diagrams and temperature dependence of dielectric susceptibility.
Magnetic properties of the multiferroics Bi1−xCaxFe1−xMnxO3 and Bi1−xCaxFe1−xTixO3
Authors: Troyanchuk I. O. , Bushinsky M. V. , Chobot A. N. , Mantytskaya O. S. , Tereshko N. V. , Chobot G. M. , Sirenko V. A. , Eremenko V. V.
Published: January 2017

This is a study of the crystalline structure and magnetic properties of the multiferroics Bi1−xCaxFe1−xMexO3 (Me = Mn, Ti). It is shown that Mn and Ti are in a quadrivalent state and the oxygen stoichiometry is conserved. The Me = Mn series undergoes a conversion at x = 0.19 from a polar rhombohedral phase (R3c) to a nonpolar orthorhombic phase (Pnma). A similar transition in the Me = Ti series was observed at x = 0.25. In both series, the polar phase (x ≥ 0.1) is weakly ferromagnetic. The spontaneous magnetization of the titanium series, however, exceeds that of the manganese series by more than a factor of three, despite the fact that Ti4+ is a diamagnetic ion. The residual magnetization of the titanium series decreases with rising temperature, while that of the manganese series increases anomalously within the interval 0.1 ≤ x ≤ 0.22. This behavior of the magnetic properties of the manganese series is explained by the extremely high sensitivity of the magnetic anisotropy to changes in the parameters of the crystal lattice, which leads to spin reversal.
Magnetodielectrical and magnetopiezoelectrical effects in NdFe3(BO3)4
Authors: Bilych I. V. , Zhekov K. R. , Gaydamak T. N. , Gudim I. A. , Zvyagina G. A. , Fil V. D.
Published: January 2017

Magnetodielectric (magnetocapacitance) and magnetopiezoelectric effects in neodymium ferroborate are systematically investigated. The existence of a previously observed magnetopiezoelectric effect in samarium ferroborate is confirmed. This effect consists in indirect renormalization of the piezoelectric modulus as a result of the combined action of the magnetoelectric and magnetoelastic mechanisms. The manifestation of a new type of phenomena—direct renormalization of the piezoelectric interaction in a magnetically ordered phase—is observed. The ratio of the contributions of the rare-earth and iron systems to the magnetoelectric interaction is estimated. It is shown that the latter plays a ballast role, impeding orientation fluctuations of the magnetic structure as a whole. The boundaries of existence of the helicoidal phase on the H-T plane are determined. The phenomenological interpretation of the studied effects is given.
Structure defects, phase transitions, magnetic resonance and magneto-transport properties of La0.6–xEuxSr0.3Mn1.1O3–δ ceramics
Authors: Liedienov N. A. , Pashchenko A. V. , Pashchenko V. P. , Prokopenko V. K. , Revenko Yu. F. , Mazur A. S. , Sycheva V. Ya. , Kamenev V. I. , Levchenko G. G.
Published: January 2017

Structure and its defects, magnetic resonance and magneto-transport properties of La0.6–xEuxSr0.3Mn1.1O3–δ magnetoresistive ceramics were investigated by x-ray diffraction, thermogravimetric, resistance, magnetic, 55Mn NMR and magnetoresistance methods. It was found that isovalent substitution of lanthanum by europium A-cation of a smaller ionic radius increases the structural imperfection and leads to a symmetry change from the rhombohedrally distorted perovskite structure of R3¯c symmetry to the pseudocubic type. It was shown that the real structure contains anionic and cationic vacancies, the concentrations of which increases with the Eu concentration and the sintering temperature tann. A decrease in the temperature of the metal–semiconductor Tms and ferromagnetic–paramagnetic TC phase transitions as well as an increase in the resistivity ρ and the activation energy Ea with increasing x are due to an increase in vacancy concentration, which weakens the high-frequency electron double exchange Mn3+ ↔ O2– ↔ Mn4+. The crystal structure of the compositions x = 0 and 0.1 contains nanostructured planar clusters, causing anomalous magnetic hysteresis at T = 77 K. Broad asymmetric 55Mn NMR spectra confirm high-frequency electron double exchange Mn3+(3d4) ↔ O2–(2p6) ↔ Mn4+(3d3) and indicate inhomogeneity of the manganese environment due to the surrounding ions and vacancies. The effective local fields of the hyperfine interaction HHF at 55Mn nuclei have been calculated by decomposing asymmetric NMR spectra into three Gaussian components. The constructed experimental phase diagram of the magnetic and conducting states of the La0.6–xEuxSr0.3Mn1.1O3–δ ceramics revealed strong correlation between the composition, structural imperfection, phase state, and magnetotransport properties of rare-earth manganites.
Compact low power infrared tube furnace for in situ X-ray powder diffraction
Authors: Doran A. , Schlicker L. , Beavers C. M. , Bhat S. , Bekheet M. F. , Gurlo A.
Published: January 2017

We describe the development and implementation of a compact, low power, infrared heated tube furnace for in situ powder X-ray diffraction experiments. Our silicon carbide (SiC) based furnace design exhibits outstanding thermal performance in terms of accuracy control and temperature ramping rates while simultaneously being easy to use, robust to abuse and, due to its small size and low power, producing minimal impact on surrounding equipment. Temperatures in air in excess of 1100 °C can be controlled at an accuracy of better than 1%, with temperature ramping rates up to 100 °C/s. The complete “add-in” device, minus power supply, fits in a cylindrical volume approximately 15 cm long and 6 cm in diameter and resides as close as 1 cm from other sensitive components of our experimental synchrotron endstation without adverse effects.
X-ray parameters of a nanocrystalline titanium microstructure, obtained via cryodeformation
Authors: Plotnikova Yu. M. , Braude I. S. , Moskalenko V. A.
Published: January 2017

A study of how reducing thickness by rolling at liquid nitrogen temperatures affects the deformation parameters of BT1-0 titanium microstructure, conducted using x-ray diffraction (XRD). The nanograin structure that formed due to cryodeformation was studied by analyzing the relative integrated intensity of the diffraction peaks, and by determining the size of the crystallites (coherent scattering regions) L, and microstrain values ⟨ε2⟩1/2. The obtained data were compared with the results of optical and transmission electron microscopy. The effect of slip and twinning activity on the parameters of the low-temperature deformation microstructure is analyzed. In ultrafine-grain and nanocrystalline titanium there is a close correlation between the size of the crystallites obtained using XRD, and the sizes of the grains observed during electron microscopic studies. It is established that there is a limiting average grain size that is attained by crystallites during the formation of a nanocrystalline state. The correlation between the grain sizes and the crystallites, typical for nanocrystalline materials, can indicate that the internal structure of the nanosized grains in nanocrystalline titanium obtained via cryomechanical grain structure fragmentation, is sufficiently perfect. The given results serve as a confirmation of the assumption that it is impossible for the dislocations responsible for lattice distortions to accumulate in nanograins.
Hydrodynamic model of screen channel liquid acquisition devices for in-space cryogenic propellant management
Authors: Darr S. R. , Camarotti C. F. , Hartwig J. W. , Chung J. N.
Published: January 2017

Technologies that enable the storage and transfer of cryogenic propellants in space will be needed for the next generation vehicles that will carry humans to Mars. One of the candidate technologies is the screen channel liquid acquisition device (LAD), which uses a metal woven wire mesh to separate the liquid and vapor phases so that single-phase liquid propellant can be transferred in microgravity. In this work, an experiment is carried out that provides measurements of the velocity and pressure fields in a screen channel LAD. These data are used to validate a new analytical solution of the liquid flow through a screen channel LAD. This hydrodynamic model, which accounts for non-uniform injection through the screen, is compared with the traditional pressure term summation model which assumes a constant, uniform injection velocity. Results show that the new model performs best against the new data and historical data. The velocity measurements inside the screen channel LAD are used to provide a more accurate velocity profile which further improves the new model. The result of this work is a predictive tool that will instill confidence in the design of screen channel LADs for future in-space propulsion systems.
Hopping charge transport in amorphous semiconductors with the spatially correlated exponential density of states
Authors: Novikov S. V.
Published: January 2017

Hopping charge transport in amorphous semiconductors having spatially correlated exponential density of states has been considered. Average carrier velocity is exactly calculated for the quasi-equilibrium (nondispersive) transport regime. We suggest also a heuristic approach for the consideration of the carrier velocity for the non-equilibrium dispersive regime.
Plastic flow of solid 3He through a porous elastic film
Authors: Lisunov A. A. , Maidanov V. A. , Rubanskyi V. Yu. , Rubets S. P. , Rudavskii E. Ya. , Smirnov S. N.
Published: January 2017

A study of plastic flow of solid 3He through a metalized porous elastic polymer film frozen into the crystal was carried out in the temperature range of 0.1–1 K. The flow was due to mechanical stresses in the crystal induced by external electrical forces. The plastic flow rate of solid helium was determined by measuring the capacitance changes of a capacitor in which the metalized surface of the film served as a movable electrode. Two different regions could be clearly identified on the temperature dependence of the plastic flow rate V(T). Above ∼200 mK, V drops exponentially with decreasing temperature, which corresponds to the thermally activated regime of plastic flow. At lower temperatures, the rate V is temperature independent, indicating quantum plastic flow. A detailed analysis of the experimental data was performed in the thermally activated region. The empirical values of the following parameters were defined: the activation volume and energy and the yield strength, corresponding to the onset of macroscopic plastic flow. It was found that the value of the activation volume is 30–70 fold the atomic volume, indicating that the scale of structural rearrangements in the crystal at elementary acts of plastic flow is significantly greater than the atomic size. At the same time the activation energy is close to the vacancy activation energy. The obtained experimental data were analyzed within the framework of the vacancy diffusion and dislocation models of plastic flow. In the dislocation model we estimated the temperature below which the dislocations overcome the Peierls barriers by quantum tunneling. The Appendix discusses the physical basis of the methodology applied as well as the results of the theory of dislocation motion in the Peierls potential, which were used to analyze the characteristics of the plastic flow of solid 3He.
Highly effective electronic passivation of silicon surfaces by atomic layer deposited hafnium oxide
Authors: Cui Jie , Wan Yimao , Cui Yanfeng , Chen Yifeng , Verlinden Pierre , Cuevas Andres
Published: January 2017

This paper investigates the application of hafnium oxide (HfO2) thin films to crystalline silicon (c-Si) solar cells. Excellent passivation of both n- and p-type crystalline silicon surfaces has been achieved by the application of thin HfO2 films prepared by atomic layer deposition. Effective surface recombination velocities as low as 3.3 and 9.9 cm s−1 have been recorded with 15 nm thick films on n- and p-type 1 Ω cm c-Si, respectively. The surface passivation by HfO2 is activated at 350 °C by a forming gas anneal. Capacitance voltage measurement shows an interface state density of 3.6 × 1010 cm−2 eV−1 and a positive charge density of 5 × 1011 cm−2 on annealed p-type 1 Ω cm c-Si. X-ray diffraction unveils a positive correlation between surface recombination and crystallinity of the HfO2 and a dependence of the crystallinity on both annealing temperature and film thickness. In summary, HfO2 is demonstrated to be an excellent candidate for surface passivation of crystalline silicon solar cells.
Solution-processed multilayer polymer light-emitting diode without intermixing
Authors: Kasparek C. , Blom P. W. M.
Published: January 2017

The intermixing of two emissive layers in a four-layer solution-processed polymeric light-emitting diode with a hole injection, two emissive layers, and one hole-blocking layer is investigated. The relative emission of both emissive layers is measured and compared to a calculated recombination profile across the device using drift-diffusion simulations. A good agreement between the measured and calculated relative emission was found, supporting that there is no intermixing in the two emissive materials.
Ab initio Study of Anharmonic Force Field and Spectroscopic Constants for Germanium Dichloride
Authors: Pang Wei-xiu , Sun Yun-bin , Zhao Jian-jun , Lu Yi
Published: January 2017

Ab initio study of the equilibrium structure, spectroscopy constants, and anharmonic force field for several isotopomers of germanium dichloride (70GeCl2, 72GeCl2, and 76GeCl2) have been carried out at the MP2 and CCSD(T) levels of theory using cc-pVTZ basis set. The calculated geometries, rotational constants, vibration-rotation interaction constants, harmonic frequencies, anharmonic constants, quartic and sextic centrifugal distortion constants, cubic and quartic force constants are compared with experimental data. For small mass differences of the Ge isotopes, the isotopic effects for germanium dichloride are much weaker. The agreements are satisfactory for these two methods, but the deviations of CCSD(T) results are slightly larger than that of MP2, because of CCSD(T)'s inadequate treatment of electron correlation in hypervalent Cl atom.
Electrocatalytic Oxidation of Calcium Folinate on Carboxyl Graphene Modified CuxO/Cu Electrode
Authors: Wang Li-wen , Wu Shou-guo , Shi Tian-yang , Wei Wei , Pan Pan
Published: January 2017

Carboxyl graphene modified CuxO/Cu electrode was fabricated. The bare copper electrode was firstly anodic polarized in 1.0 mol/L NaOH solution in order to get CuxO nanoparticles, then the carboxyl graphene (CG) was electrodeposited on the CuxO/Cu electrode by cyclic potential sweeping. The electrocatalytic oxidation behaviors of calcium folinate (CF) at the graphene modified CuxO/Cu electrode were investigated by cyclic voltammetry. A positive scan polarization reverse catalytic voltammetry was used to obtain the pure catalytic oxidation current. The graphene modified CuxO/Cu electrode was served as the electrochemical sensor of CF, a highly sensitivity of 22.0 µA·(µmol/µL)−1cm−2 was achieved, and the current response was linear with increasing CF concentration in the range of 2.0×10−7 mol/L to 2.0×10−5 mol/L, which crossed three orders of magnitude, and the detection limit was found 7.6×10−8 mol/L (S/N=3). In addition, the proposed sensor was successfully applied in determination of CF in drug sample.
Orientation Angle of Molecules at Hexadecane-Water Interface Studied with Total Internal Reflection Second Harmonic Generation
Authors: Zhang Li-bo , Fang Hui , Chen Shun-li , Zhu Xue-feng , Gan Wei
Published: January 2017

The orientation angle is an important parameter that reflects the structure of molecules at interfaces. In order to obtain this parameter, second order nonlinear spectroscopic techniques including second harmonic generation (SHG) and sum frequency generation-vibrational spectroscopy (SFG-VS) have been successfully applied through analysis of the nonlinear signal from various polarizations. In some SHG and SFG-VS experiments, total internal reflection (TIR) configuration has been adopted to get enhanced signals. However, the reports on the detailed procedure of the polarization analysis and the calculation of the orientation angle of interfacial molecules under TIR configuration are still very few. In this paper, we measured the orientation angles of two molecules at the hexadecane-water interface under TIR and Non-TIR experimental configurations. The results measured from polarization analysis in TIR configuration consist with those obtained from Non-TIR configuration. This work demonstrates the feasibility and accuracy of polarization analysis in the determination of the orientation angle of molecules at the interfaces under TIR-SHG configuration.
Preparation and Visible-Light Photocatalytic Activity of FeTPP-Cr-TiO2 Microspheres
Authors: Yao Bing-hua , Peng Chao , He Yang-qing , Zhang Wen , Yu Yan , Zhang Ting
Published: January 2017

Tetraphenyl-porphyrin iron (FeTPP) was chosen to sensitize Cr doped TiO2 (Cr-TiO2) nanoparticles, a novel multimodified photocatalyst FeTPP-Cr-TiO2 with excellent visible-light photocatalytic activity was successfully synthesized. The FeTPP-Cr-TiO2 microspheres were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electronic microscopy, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectra and N2 adsorption-desorption isotherms. The photocatalytic activity of FeTPP-Cr-TiO2 was evaluated by degradations of methylene blue in aqueous solution under irradiation with Xe lamp (150 W). The results showed that the FeTPP-Cr-TiO2 multimodified photocatalyst was anatase phase with high specific surface area (74.7 m2/g), and exhibited higher photocatalytic degradation efficiency than Cr-TiO2 and FeTPP-TiO2. The photocatalytic degradations of three quinolone antibiotics (lomefloxacin, norfloxacin, and ofloxacin) were further estimated for the feasibility of practical application of catalyst in wastewater treatment. It is desirable that photodegradation of antibiotics with FeTPP-Cr-TiO2 achieved pretty high degradation rates and all followed the pseudo first-order reaction model, and the rate constants k of 3.02×10−2, 2.81×10−2, and 3.86×10−2 min−1 and the half-lifes t1/2 of 22.9, 24.6, and 17.9 min were achieved respectively.
Transcription factor Xpp1 is a switch between primary and secondary fungal metabolism
Authors: Derntl Christian , Kluger Bernhard , Bueschl Christoph , Schuhmacher Rainer , Mach Robert L. , Mach-Aigner Astrid R.
Published: January 2017

Significance

Fungi produce a vast number of different chemical compounds via secondary metabolism. These compounds are of great interest because of their potential applicability in medicine, pharmacy, and biotechnology. In addition, a number of such compounds are toxins that potentially represent severe threats to human and animal health. However, under standard cultivation conditions, fungal secondary metabolism remains largely inactive. Here, we show that the deletion of the regulator Xylanase promoter binding protein 1 (Xpp1) results in the production of significantly more secondary metabolites in terms of both number and concentration. Because homologs of Xpp1 exist in fungi with numerous bioactive secondary metabolites, our results can lead to the discovery of secondary metabolites.
Different clades and traits yield similar grassland functional responses
Authors: Forrestel Elisabeth J. , Donoghue Michael J. , Edwards Erika J. , Jetz Walter , du Toit Justin C. O. , Smith Melinda D.
Published: January 2017

Significance

Plant functional traits—characteristics that influence performance or fitness—are increasingly being used to model important ecosystem properties such as primary production. These approaches assume that traits confer specific functions or responses under given environmental conditions, and that these trait–environment and trait–function relationships can be generalized globally irrespective of a region's history or differences in species assemblages. Here, we test this assumption in grasslands with distinct histories and find that different combinations of trait values can yield similar productivity–precipitation relationships. Our study highlights a missing link in the development of trait-based approaches to modeling ecosystem function, namely that there is not necessarily a single solution or set of traits that yields higher function in a given environment.
Redox crisis underlies conditional light–dark lethality in cyanobacterial mutants that lack the circadian regulator, RpaA
Authors: Diamond Spencer , Rubin Benjamin E. , Shultzaberger Ryan K. , Chen You , Barber Chase D. , Golden Susan S.
Published: January 2017

Significance

The evolution of photosynthetic cyanobacteria under 24-h cycles of light and darkness selected for a robust circadian clock. Understanding how cyanobacteria integrate circadian clock signals with natural light–dark cycles to control metabolism is critical, because these organisms are central to global carbon cycling and hold promise for development of renewable energy. Here we assess how the circadian transcription factor regulator of phycobilisome association A (RpaA) influences metabolism as a cyanobacterium goes through a light-to-dark transition. The data show that RpaA plays a key role in maintaining metabolic stability during the night period. Additionally, RpaA is important in controlling redox balance, which in turn is very important for regulating metabolism at night.
Iconic photographs and the ebb and flow of empathic response to humanitarian disasters
Authors: Slovic Paul , Västfjäll Daniel , Erlandsson Arvid , Gregory Robin
Published: January 2017

Significance

We cannot assume that the statistics of mass human crises will capture our attention or move us to take action, no matter how large the numbers. The data that we present show that the world was basically asleep as the body count in the Syrian war rose steadily into the hundreds of thousands. The iconic image of a young Syrian child, lying face-down on a beach, woke the world for a brief time, bringing much-needed attention to the war and the plight of its many victims. But this empathic response was short-lived. We outline the need for better laws, institutions, and decision-making procedures to channel empathy into appropriate and effective humanitarian actions by individuals and their governments.
A second decoupling between merging binary black holes and the inner disc – impact on the electromagnetic counterpart
Authors: Fontecilla Camilo , Chen Xian , Cuadra Jorge
Published: January 2017

The coalescence of two supermassive black holes (SMBHs) produces powerful gravitational wave radiation and, if gas is present in the vicinity, also an electromagnetic (EM) counterpart. In the standard picture, an EM outburst will be produced when the binary ‘decouples’ from the circum-binary disc and starts ‘squeezing’ the disc inside the secondary orbit, resulting in its quick accretion on to the primary black hole. Here, we use analytical arguments and numerical simulations to show that the disc within about 20 RS of an SMBH survives the merger without being depleted. The reason is a ‘second decoupling’: the inner disc thickens due to tidal heating and inefficient cooling, effectively decoupling from the interaction of the binary. We show that this second decoupling quenches the heating sources in the disc ${\cal O}(10^2)$ d before coalescence. This will render the peak UV/X-ray luminosity significantly weaker than previously thought. After the merger, the residual disc cools down and expands, merging with the outer disc rather than being completely accreted. This results in continuous EM emission, hindering the detection of the cut-off and re-brightening proposed in earlier studies.
Visualization of Political Networks
Authors: Pfeffer Jürgen
Published: January 2017

Network visualization and political networks have a long history, and some of the earliest and most effective network visualizations have been about power and influence. Now as in the past, network visualization is one of the most effective tools for both exploratory analysis and the communication of scientific results. This chapter discusses the rhetorical, technical, and aesthetic principles that underlie successful network visualizations. The chapter covers automated layout algorithms as well as layouts resulting from the substance of the network. Aspects of visualizing multivariate network data are also discussed. The use of additional visual elements such as color and size is deliberated. The various topics of this chapter are contrasted with issues resulting from human perception and with frequently encountered visualization challenges, such as those encountered when working with dense networks.
A Metatheory of Race
Authors: Glasgow Josh
Published: January 2017

Arguments from reference are widely used by people who otherwise disagree about race. They are used by people who think that race is an illusion (antirealists). They are used by people who think that race is socially real (constructivists). Theories of race across the disciplines normally define “race” descriptively to defend their views on what race is. This normal approach has come under attack, from two angles: that descriptive definitions are flawed, and that using any semantic arguments is fruitless. However, normal race theory can be defended against these objections, because the mode of reference relevant to race is descriptive and there is no privileged nondescriptive mode of reference that is (can be) relevant to the race debates.
Du Bois, Appiah, and Outlaw on Racial Identity
Authors: Jeffers Chike
Published: January 2017

W. E. B. Du Bois’s “The Conservation of Races” has greatly shaped contemporary philosophy of race, and one of the ways in which it has this effect is through the debate between Kwame Anthony Appiah and Lucius Outlaw. Du Bois, Appiah, and Outlaw all offer important perspectives on the value of racial identity. Appiah’s article helped stimulate debates about the nature and existence of race that remain central to philosophy of race today. The “Appiah-Outlaw debate” has often been treated as the most important instance of the conflict over “Conservation.” Through evolution on Appiah’s part, there has been a shift from sharp disagreement to significant consensus.
Biological Anthropology, Population Genetics, and Race
Authors: Relethford John H.
Published: January 2017

Recent developments in molecular genetics have given us much information about DNA markers and a detailed look at evolutionary causes of genetic variation in humans. Patterns of genetic variation within populations and genetic differences among populations is best understood in light of our species’ African origin 200,000 years ago and the subsequent dispersion of human populations throughout the world 70,000 to 100,000 years ago. Although an evolutionary focus on genetic variation using methods from the field of population genetics provides us with considerable insight regarding our history, older ideas based on traditional definitions of biological race have no explanatory value.
From Scientific Racism to Neoliberal Biopolitics
Authors: McWhorter Ladelle
Published: January 2017

Although Foucault did not undertake a genealogy of race or racism, his work contains fragments of such a genealogy and important conceptual resources for constructing one. In particular, his concepts of biopower and normalization can help us expose and analyze how race shifted in meaning from lineage (in the seventeenth century) to morphology (in the eighteenth century) and then to biology, and thus how racist beliefs, attitudes, and practices emerged, developed, and adapted. The history of scientific racism and the eugenics movement still informs institutions and practices of discrimination against, and oppression of, racialized groups.
Ethnological Theories of Race/Sex in Nineteenth-Century Black Thought
Authors: Curry Tommy J.
Published: January 2017

The presumed opposition between man and woman is a very recent phenomenon in the historical scope of gender. This is especially true for black Americans who were thought to be “ungendered” throughout history. In the nineteenth century only the white race was gendered—blacks were believed to be too savage to share these distinctions. The theory of gender that white ethnologists applied to black Americans in the nineteenth and early twentieth centuries was also taken up by blacks, with implications for our current intersectional historiographies.
State Racism, State Violence, and Vulnerable Solidarity
Authors: Cherry Myisha
Published: January 2017

What makes #BlackLivesMatter unique is the implication that it isn’t only some black lives that matter, that is, not only the mostly commonly referenced male lives. Rather, the hashtag suggests that all black lives matter, including queer, trans, disabled, and female. This movement includes all those black lives who have been marginalized within the black liberation tradition, as well as in greater society. The movement highlights the ways in which black people have been traditionally deprived of dignity and human rights. State racism and state violence are sustained together. The law creates a “subrace” out of those whom white society fears and holds in contempt. This leaves not only black Americans, but all citizens vulnerable. A way to fight this form of racism is not only to create a solidarity among the oppressed members of the subrace but to create a solidarity with all members, in “vulnerable solidarity.”
Philosophy and the Racial Contract
Authors: Mills Charles W.
Published: January 2017

The racial contract is both racist reality and, as “the racial contract,” it is a concept that should be thought of as a “device of representation” for theorizing racial oppression within a social contract framework. Mills here looks at the influence of the racial contract (disquotationally, as a racist reality) on the views of white political philosophers and on the formation of modern white-dominated racial polities, as well as the possible use of the “racial contract” to theorize corrective racial justice. Finally, he discusses the reception of his book, The Racial Contract, in the twenty years since its publication.
John Locke, Racism, Slavery, and Indian Lands
Authors: Uzgalis William
Published: January 2017

Locke owned stock in slave trading companies and was secretary of the Lords Proprietors of the Carolinas, where slavery was constitutionally permitted. He had two notions of slavery: legitimate slavery was captivity with forced labor imposed by the just winning side in a war; illegitimate slavery was an authoritarian deprivation of natural rights. Locke did not try to justify either black slavery or the oppression of Amerindians. In The Two Treatises of Government, Locke argued against the advocates of absolute monarchy. The arguments for absolute monarchy and colonial slavery turn out to be the same. So in arguing against the one, Locke could not help but argue against the other. Examining the natural rights tradition to which Locke’s work belongs confirms this. Locke could have defended colonial slavery by building on popular ideas of his colleagues and predecessors, but there is no textual evidence that he did that or that he advocated seizing Indian agricultural land.
Looking for Alain Locke
Authors: Harris Leonard
Published: January 2017

Alain Locke (1885–1954) was the first African American Rhodes Scholar (1907–1910) who received a PhD in philosophy from Harvard (1918), and he was the intellectual architect of the Harlem Renaissance. Leonard Harris’s search for Locke included tracking down his unburied ashes and considering the obstacles preventing publications about and by Locke. Locke was the author of critical pragmatism and of fallibalism, or clarifying the warrant of a hypothesis by considering consequences. He shifted the empiricism of classical pragmatism by rejecting “science” as a dominant model for reasoning and promoting a strong account of cosmopolitanism, as contrary to racial nationalism. Locke’s value relativism is contrary to value absolutism, including Marx’s labor theory of value and Kant’s transcendentalism. Locke was finally interned in the Congressional Cemetery, September 13, 2014, sixty years after his death.
Kantian Racism and Kantian Teleology
Authors: Boxill Bernard
Published: January 2017

Appalled by Kant’s views on race, some Kantians suggest that these views are unrelated to his central moral teaching that every human being “exists as an end in itself and not merely as a means to be arbitrarily used by this or that will.” But Kant developed his racial views because of his teleological view that we regard the history of the human species as the completion of a hidden plan of nature to establish an externally perfect state constitution as the necessary means to the end of developing all human predispositions. To evade the difficulty, Kantians may claim that Kant’s teleology and moral theory are not essentially related, but Kant thought that they were and close textual analysis supports their connection.
Race, Definition, and Science
Authors: Atkin Albert
Published: January 2017

Philosophical concerns about the reality of race often depend on the examination of our ordinary race concepts, and whether the biological sciences might support the existence of those concepts. We can approach these philosophical concerns by looking at how we might define a race concept from both ordinary discourse (the folk definition), and from the viewpoint of the biological sciences (as a subspecies or population cluster). After noting the difficulties with giving a satisfactory definition of race in both domains, we can see more clearly why our race concepts cannot claim any obvious support from the biological sciences.
Indigeneity and US Settler Colonialism
Authors: Whyte Kyle Powys
Published: January 2017

Indigenous identity in the US context presents many difficulties, including issues related to the use of blood quantum, ethnic fraud, and tribal disenrollment. These difficulties should be understood as oppressive dilemmas and disappearances that are built into those structures of US settler colonialism that seek to erase indigenous peoples. Kim TallBear suggests at least one possible alternative for addressing issues associated with indigeneity and settler erasure. TallBear’s alternative is multifaceted, focusing on collective self-determination, survival, and land, and it can be used—as just one example—to understand current uses of indigeneity in some contemporary indigenous environmental justice projects.