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Sample records for auni aasmaa lya

  1. George Pólya – Educator Extraordinaire

    Indian Academy of Sciences (India)

    IAS Admin

    International Congress on Mathematical Education in 1972, Pólya was honoured along with. Jean Piaget. ... A teacher of traditional mathematics is in danger of becoming a down monkey, and a teacher of modern mathematics an up monkey.

  2. Interface stress in Au/Ni multilayers

    DEFF Research Database (Denmark)

    Schweitz, K.O.; Böttiger, J.; Chevallier, J.

    2000-01-01

    The effect of intermixing on the apparent interface stress is studied in -textured dc-magnetron sputtered Au/Ni multilayers by use of two methods commonly used for determining interface stress. The method using profilometry and in-plane x-ray diffraction does not take intermixing...... into account and yields an apparent interface stress of -8.46 +/- 0.99 J m(-2). However, observed discrepancies between model calculations and measured high-angle x-ray diffractograms indicate intermixing, and by use of the profilometry and sin(2) psi method the real interface stress value of -2.69 +/- 0.43 J...... m(-2) is found. This method also reveals a significant and systematic change of the stress-free lattice parameter of both constituents as a function of modulation period which is shown to account for the difference between the two findings. The method using in-plane diffraction is thus shown...

  3. lya number and first return of bursty random walk: Rigorous solutions

    Science.gov (United States)

    Wan, J.; Xu, X. P.

    2012-03-01

    The recurrence properties of random walks can be characterized by Pólya number, i.e., the probability that the walker has returned to the origin at least once. In this paper, we investigate Pólya number and first return for bursty random walk on a line, in which the walk has different step size and moving probabilities. Using the concept of the Catalan number, we obtain exact results for first return probability, the average first return time and Pólya number for the first time. We show that Pólya number displays two different functional behavior when the walk deviates from the recurrent point. By utilizing the Lagrange inversion formula, we interpret our findings by transferring Pólya number to the closed-form solutions of an inverse function. We also calculate Pólya number using another approach, which corroborates our results and conclusions. Finally, we consider the recurrence properties and Pólya number of two variations of the bursty random walk model.

  4. Wetting - Dewetting Transitions of Au/Ni Bilayer Films

    Science.gov (United States)

    Cen, Xi

    Thin films deposited at low temperatures are often kinetically constrained and will dewet the underlying substrate when annealed. Solid state dewetting is driven by the minimization of the total free energy of thin film-substrate interface and free surface, and mostly occurs through surface diffusion. Dewetting is a serious concern in microelectronics reliability. However, it can also be utilized for the self-assembly of nanostructures with potentials in storage, catalysis, or transistors. Therefore, a fundamental understanding of the dewetting behavior of thin metal films is critical for improving the thermal stability of microelectronics and controlling the order of self-assembled nanostructures. Mechanisms for dewetting of single layer films have been studied extensively. However little work has been reported on multilayer or alloyed thin films. In the thesis, the solid state dewetting of Au/Ni bilayer films deposited on SiO2/Si substrates was investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and aberration corrected scanning TEM (STEM). Ex-situ SEM and TEM studies were performed with in-situ TEM heating characterization to identify the mechanisms during the dewetting process of Au/Ni bilayer films. The solid state dewetting of Au/Ni bilayer films from SiO2/Si substrates exhibits both homogeneous and localized dewetting of Ni and long-edge retraction for Au under isothermal annealing condition. The top Au layer retracts up to 1 mm from the edge of the substrate wafer to reduce the energetically unfavored Au/Ni interface. In contrast, Ni dewets and agglomerates locally due to its limited diffusivity compared to Au. Film morphology and local chemical composition varies significantly across hundreds of microns along the direction normal to the retracting edge. Besides long range edge receding, localized dewetting shows significant changes in film morphology and chemical distribution. Both Au and Ni shows texturing. Despite

  5. Solid-state dewetting of Au/Ni bilayers: The effect of alloying on morphology evolution

    International Nuclear Information System (INIS)

    Herz, A.; Wang, D.; Kups, Th.; Schaaf, P.

    2014-01-01

    The solid-state dewetting of thin Au/Ni bilayers deposited onto SiO 2 /Si substrates is investigated. A rapid thermal treatment is used to induce the dewetting process by an increase in temperature. The evolution of the (111) peaks of X-ray diffraction reveals a characteristic change due to mixing of Au and Ni. At low temperature, the Au-Ni thin film is found to break up at the phase boundaries and growing voids are shown to be surrounded by a Ni-rich phase. Branch-like void growth is observed. Upon annealing at increasing temperatures, Au-Ni solid solutions are formed well above the bulk equilibrium solubility of Au and Ni. It is found that this metastable phase formation makes the Au-Ni thin film less vulnerable to rupturing. Moreover, growth mode of still evolving voids changes into a more regular, faceted one due to alloying. Finally, it is shown that annealing above the miscibility gap forms supersaturated, well-oriented Au-Ni solid solution agglomerates via dewetting.

  6. Solid-state dewetting of Au/Ni bilayers: The effect of alloying on morphology evolution

    Energy Technology Data Exchange (ETDEWEB)

    Herz, A.; Wang, D., E-mail: dong.wang@tu-ilmenau.de; Kups, Th.; Schaaf, P. [Institute of Materials Engineering and Institute of Micro- and Nanotechnologies MacroNano, Chair Materials for Electronics and Electrical Engineering, TU Ilmenau, Ilmenau 98693 (Germany)

    2014-07-28

    The solid-state dewetting of thin Au/Ni bilayers deposited onto SiO{sub 2}/Si substrates is investigated. A rapid thermal treatment is used to induce the dewetting process by an increase in temperature. The evolution of the (111) peaks of X-ray diffraction reveals a characteristic change due to mixing of Au and Ni. At low temperature, the Au-Ni thin film is found to break up at the phase boundaries and growing voids are shown to be surrounded by a Ni-rich phase. Branch-like void growth is observed. Upon annealing at increasing temperatures, Au-Ni solid solutions are formed well above the bulk equilibrium solubility of Au and Ni. It is found that this metastable phase formation makes the Au-Ni thin film less vulnerable to rupturing. Moreover, growth mode of still evolving voids changes into a more regular, faceted one due to alloying. Finally, it is shown that annealing above the miscibility gap forms supersaturated, well-oriented Au-Ni solid solution agglomerates via dewetting.

  7. Studying language change using price equation and Pólya-urn dynamics.

    Science.gov (United States)

    Gong, Tao; Shuai, Lan; Tamariz, Mónica; Jäger, Gerhard

    2012-01-01

    Language change takes place primarily via diffusion of linguistic variants in a population of individuals. Identifying selective pressures on this process is important not only to construe and predict changes, but also to inform theories of evolutionary dynamics of socio-cultural factors. In this paper, we advocate the Price equation from evolutionary biology and the Pólya-urn dynamics from contagion studies as efficient ways to discover selective pressures. Using the Price equation to process the simulation results of a computer model that follows the Pólya-urn dynamics, we analyze theoretically a variety of factors that could affect language change, including variant prestige, transmission error, individual influence and preference, and social structure. Among these factors, variant prestige is identified as the sole selective pressure, whereas others help modulate the degree of diffusion only if variant prestige is involved. This multidisciplinary study discerns the primary and complementary roles of linguistic, individual learning, and socio-cultural factors in language change, and offers insight into empirical studies of language change.

  8. In memory of Alois Apfelbeck: An Interconnection between Cayley-Eisenstein-Pólya and Landau Probability Distributions

    Directory of Open Access Journals (Sweden)

    Vladimír Vojta

    2013-01-01

    Full Text Available The interconnection between the Cayley-Eisenstein-Pólya distribution and the Landau distribution is studied, and possibly new transform pairs for the Laplace and Mellin transform and integral expressions for the Lambert W function have been found.

  9. Improvement of the wear resistance of electroplated Au-Ni coatings by Zr ion bombardment of Ni-B sublayer

    International Nuclear Information System (INIS)

    Lyazgin, Alexander; Shugurov, Artur; Sergeev, Viktor; Neufeld, Vasily; Panin, Alexey; Shesterikov, Evgeny

    2015-01-01

    The effect of bombardment of the Ni-B sublayer by Zr ion beams on the surface morphology and tribomechanical properties of Au-Ni coatings was investigated. It was found that the treatment has no significant effect on the surface roughness and grain size of the Au-Ni coatings, while it provides essential reducing of their friction coefficient and improvement of wear resistance. It is shown that increased wear resistance of these coatings was caused by their strain hardening resulted from localization of plastic strain. The optimal Zr fluence were determined that provide the maximum reduction of linear wear of the coatings

  10. Cross-sectional characterization of the dewetting of a Au/Ni bilayer film

    Energy Technology Data Exchange (ETDEWEB)

    Cen, Xi; Thron, Andrew M.; Zhang, Xinming; Benthem, Klaus van

    2017-07-15

    The solid state dewetting of Au/Ni bilayer films was investigated by cross-sectional transmission electron microscopy techniques, including energy-dispersive X-ray spectroscopy, electron energy-loss spectroscopy and precession electron diffraction. After annealing under high vacuum conditions the early stage of film agglomeration revealed significant changes in film morphology and chemical distribution. Both Au and Ni showed texturing. Despite the initial deposition sequence of the as-deposited Au/Ni/SiO{sub 2}/Si interface structure, the majority of the metal/SiO{sub 2} interface was Au/SiO{sub 2} after annealing at 675 °C for 1 h. Void nucleation was predominantly observed at Au/Ni/SiO{sub 2} triple junctions, rather than grain boundary grooving at free surface of the metal film. Detailed cross-sectional characterization reveals that the Au/Ni interface in addition to small amounts of metal alloying strongly affects film break-up and agglomeration kinetics. The formation of Au/SiO{sub 2} interface sections is found to be energetically preferred over Ni/SiO{sub 2} due to compressive stress in the as-deposited Ni layer. Void nucleation is observed at the film/substrate interface, while the formation of voids at Ni/Au phase boundaries inside the metal film is caused by the Kirkendall effect. - Highlights: • The dewetting of Au/Ni bilayer films was studied by cross-sectional TEM techniques. • The majority of the metal/SiO{sub 2} interface was comprised of Au/SiO{sub 2} after annealing. • Void formation was dominant for hole nucleation at early dewetting stage. • The Kirkendall effect was also observed to cause the formation of voids.

  11. Facet-controlled phase separation in supersaturated Au-Ni nanoparticles upon shape equilibration

    Energy Technology Data Exchange (ETDEWEB)

    Herz, A., E-mail: andreas.herz@tu-ilmenau.de, E-mail: dong.wang@tu-ilmenau.de; Rossberg, D.; Hentschel, M.; Theska, F.; Wang, D., E-mail: andreas.herz@tu-ilmenau.de, E-mail: dong.wang@tu-ilmenau.de; Schaaf, P. [Department of Materials for Electronics and Electrical Engineering, Institute of Materials Science and Engineering and Institute of Micro- and Nanotechnologies MacroNano, TU Ilmenau, D-98693 Ilmenau (Germany); Friák, M. [Institute of Physics of Materials, Academy of Sciences of the Czech Republic, v.v.i., Žižkova 22, CZ-616 62 Brno (Czech Republic); Central European Institute of Technology, CEITEC MU, Masaryk University, Kamenice 5, CZ-625 00 Brno (Czech Republic); Holec, D. [Department of Physical Metallurgy and Materials Testing, Montanuniversität Leoben, A-8700 Leoben (Austria); Šob, M. [Central European Institute of Technology, CEITEC MU, Masaryk University, Kamenice 5, CZ-625 00 Brno (Czech Republic); Institute of Physics of Materials, Academy of Sciences of the Czech Republic, v.v.i., Žižkova 22, CZ-616 62 Brno (Czech Republic); Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, CZ-611 37 Brno (Czech Republic); Schneeweiss, O. [Institute of Physics of Materials, Academy of Sciences of the Czech Republic, v.v.i., Žižkova 22, CZ-616 62 Brno (Czech Republic)

    2015-08-17

    Solid-state dewetting is used to fabricate supersaturated, submicron-sized Au-Ni solid solution particles out of thin Au/Ni bilayers by means of a rapid thermal annealing technique. Phase separation in such particles is studied with respect to their equilibrium crystal (or Wulff) shape by subsequent annealing at elevated temperature. It is found that (100) faceting planes of the equilibrated particles are enriched with Ni and (111) faces with Au. Both phases are considered by quantum-mechanical calculations in combination with an error-reduction scheme that was developed to compensate for a missing exchange-correlation potential that would reliably describe both Au and Ni. The observed phase configuration is then related to the minimization of strongly anisotropic elastic energies of Au- and Ni-rich phases and results in a rather unique nanoparticle composite state that is characterized by nearly uniform value of elastic response to epitaxial strains all over the faceted surface. The same conclusion is yielded also by evaluating bi-axial elastic moduli when employing interpolated experimental elastic constants. This work demonstrates a useful route for studying features of physical metallurgy at the mesoscale.

  12. Cross-sectional characterization of the dewetting of a Au/Ni bilayer film.

    Science.gov (United States)

    Cen, Xi; Thron, Andrew M; Zhang, Xinming; van Benthem, Klaus

    2017-07-01

    The solid state dewetting of Au/Ni bilayer films was investigated by cross-sectional transmission electron microscopy techniques, including energy-dispersive X-ray spectroscopy, electron energy-loss spectroscopy and precession electron diffraction. After annealing under high vacuum conditions the early stage of film agglomeration revealed significant changes in film morphology and chemical distribution. Both Au and Ni showed texturing. Despite the initial deposition sequence of the as-deposited Au/Ni/SiO 2 /Si interface structure, the majority of the metal/SiO 2 interface was Au/SiO 2 after annealing at 675°C for 1h. Void nucleation was predominantly observed at Au/Ni/SiO 2 triple junctions, rather than grain boundary grooving at free surface of the metal film. Detailed cross-sectional characterization reveals that the Au/Ni interface in addition to small amounts of metal alloying strongly affects film break-up and agglomeration kinetics. The formation of Au/SiO 2 interface sections is found to be energetically preferred over Ni/SiO 2 due to compressive stress in the as-deposited Ni layer. Void nucleation is observed at the film/substrate interface, while the formation of voids at Ni/Au phase boundaries inside the metal film is caused by the Kirkendall effect. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Determination of diffusion coefficients in Au/Ni thin films by Auger electron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Abdul-Lettif, Ahmed M. [Physics Department, College of Science, Babylon University, Hilla (Iraq)

    2004-07-01

    Interdiffusion in vacuum-deposited Au/Ni thin films at temperatures in the range 200-500 C has been investigated using the Auger depth profiling technique and X-ray diffraction analysis. A modified Wipple model was used to determine the diffusion coefficients of Ni in Au to be 5.3 x 10{sup -16} cm{sup 2}/s at 500 C, 4.0 x 10{sup -17} cm{sup 2}/s at 400 C, 2.5 x 10{sup -18} cm{sup 2}/s at 300 C, and 1.2 x 10{sup -19} cm{sup 2}/s at 200 C. An activation energy of 0.87 eV was calculated. The present diffusion data differ significantly from the corresponding values extracted by some other investigators and the reasons for this disagreement were discussed. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Novas tecnologias e interações literárias: Lya Luft no ORKUT

    Directory of Open Access Journals (Sweden)

    Leani Budde

    2010-08-01

    Full Text Available http://dx.doi.org/10.5007/1807-9288.2009v5n2p141 A Internet tornou-se um instrumento de difusão de conteúdo e interação de pessoas de forma intensa e acelerada neste início dos anos 2000. Dentro dela, as comunidades virtuais constituem-se num meio democrático e inovador de interação entre pessoas com afinidades nas mais diversas áreas, assim como de apoio ou rejeição a figuras públicas, como os escritores. O artigo trata da evolução das formas virtuais de relacionamento, as comunidades do Orkut relacionadas à escritora Lya Luft, e de alguns dos significados que podem ser atribuídos a essa interação, tendo em vista contribuições dos estudos culturais e pensadores como Stuart Hall e Nestor Canclini.

  15. Solid-state dewetting of Au-Ni bi-layer films mediated through individual layer thickness and stacking sequence

    Science.gov (United States)

    Herz, Andreas; Theska, Felix; Rossberg, Diana; Kups, Thomas; Wang, Dong; Schaaf, Peter

    2018-06-01

    In the present work, the solid-state dewetting of Au-Ni bi-layer thin films deposited on SiO2/Si is systematically studied with respect to individual layer thickness and stacking sequence. For this purpose, a rapid heat treatment at medium temperatures is applied in order to examine void formation at the early stages of the dewetting. Compositional variations are realized by changing the thickness ratio of the bi-layer films, while the total thickness is maintained at 20 nm throughout the study. In the event of Au/Ni films annealed at 500 °C, crystal voids exposing the substrate are missing regardless of chemical composition. In reverse order, the number of voids per unit area in two-phase Au-Ni thin films is found to be governed by the amount of Au-rich material. At higher temperatures up to 650 °C, a decreased probability of nucleation comes at the expense of a major portion of cavities, resulting in the formation of bubbles in 15 nm Ni/5 nm Au bi-layers. Film buckling predominantly occurred at phase boundaries crossing the bubbles.

  16. Far-infrared spectra of yttrium-doped gold clusters Au(n)Y (n=1-9).

    Science.gov (United States)

    Lin, Ling; Claes, Pieterjan; Gruene, Philipp; Meijer, Gerard; Fielicke, André; Nguyen, Minh Tho; Lievens, Peter

    2010-06-21

    The geometric, spectroscopic, and electronic properties of neutral yttrium-doped gold clusters Au(n)Y (n=1-9) are studied by far-infrared multiple photon dissociation (FIR-MPD) spectroscopy and quantum chemical calculations. Comparison of the observed and calculated vibrational spectra allows the structures of the isomers present in the molecular beam to be determined. Most of the isomers for which the IR spectra agree best with experiment are calculated to be the energetically most stable ones. Attachment of xenon to the Au(n)Y cluster can cause changes in the IR spectra, which involve band shifts and band splittings. In some cases symmetry changes, as a result of the attachment of xenon atoms, were also observed. All the Au(n)Y clusters considered prefer a low spin state. In contrast to pure gold clusters, which exhibit exclusively planar lowest-energy structures for small sizes, several of the studied species are three-dimensional. This is particularly the case for Au(4)Y and Au(9)Y, while for some other sizes (n=5, 8) the 3D structures have an energy similar to that of their 2D counterparts. Several of the lowest-energy structures are quasi-2D, that is, slightly distorted from planar shapes. For all the studied species the Y atom prefers high coordination, which is different from other metal dopants in gold clusters.

  17. O (desconhecimento do rosto do outro: dimensões da (incomunicabilidade em Oswaldo França Júnior e Lya Luft

    Directory of Open Access Journals (Sweden)

    Angela Maria Salgueiro Marques

    2011-12-01

    Full Text Available O presente texto tem como objetivo analisar o tema do desconhecimento do outro em dois contos de escritores brasileiros contemporâneos: “Eu não o conheci”, de Oswaldo França Júnior, e “A Pedra da Bruxa”, de Lya Luft. Ambos refletem sobre a morte de um filho. Procede-se um estudo comparado dos textos no sentido de apontar algumas semelhanças e diferenças tanto entre aspectos formais, tais como conto e miniconto, quanto entre pontos de vista, espaço, tempo, e a questão da incomunicabilidade, à luz do conceito de “Rosto”, explorado por Emmanuel Lévinas e Giorgio Agamben, que nos auxilia a definir a causa do profundo mal-estar exposto pelos narradores desses contos.Palavras-chave: Oswaldo França Júnior; Lya Luft; Conto; Miniconto; Incomunicabilidade; Rosto.

  18. The Enhanced Catalytic Activities of Asymmetric Au-Ni Nanoparticle Decorated Halloysite-Based Nanocomposite for the Degradation of Organic Dyes

    Science.gov (United States)

    Jia, Lei; Zhou, Tao; Xu, Jun; Li, Xiaohui; Dong, Kun; Huang, Jiancui; Xu, Zhouqing

    2016-02-01

    Janus particles (JPs) are unique among the nano-/microobjects because they provide asymmetry and can thus impart drastically different chemical or physical properties. In this work, we have fabricated the magnetic halloysite nanotube (HNT)-based HNTs@Fe3O4 nanocomposite (NCs) and then anchored the Janus Au-Ni or isotropic Au nanoparticles (NPs) to the surface of external wall of sulfydryl modified magnetic nanotubes. The characterization by physical methods authenticates the successful fabrication of two different magnetic HNTs@Fe3O4@Au and HNTs@Fe3O4@Au-Ni NCs. The catalytic activity and recyclability of the two NCs have been evaluated considering the degradation of Congo red (CR) and 4-nitrophenol (4-NP) using sodium borohydride as a model reaction. The results reveal that the symmetric Au NPs participated NCs display low activity in the degradation of the above organic dyes. However, a detailed kinetic study demonstrates that the employ of bimetallic Janus Au-Ni NPs in the NCs indicates enhanced catalytic activity, owing to the structurally specific nature. Furthermore, the magnetic functional NCs reported here can be used as recyclable catalyst which can be recovered simply by magnet.

  19. The influence of thermal annealing on the characteristics of Au/Ni Schottky contacts on n-type 4 H-SiC

    Science.gov (United States)

    Omotoso, E.; Auret, F. D.; Igumbor, E.; Tunhuma, S. M.; Danga, H. T.; Ngoepe, P. N. M.; Taleatu, B. A.; Meyer, W. E.

    2018-05-01

    The effects of isochronal annealing on the electrical, morphological and structural characteristics of Au/Ni/4 H-SiC Schottky barrier diodes (SBDs) have been studied. Current-voltage ( I- V), capacitance-voltage ( C- V), deep-level transient spectroscopy, scanning electron microscope (SEM) and X-ray diffraction measurements were employed to study the thermal effect on the characteristics of the SBDs. Prior to thermal annealing of Schottky contacts, the I- V measurements results confirmed the good rectification behaviour with ideality factor of 1.06, Schottky barrier height of 1.20 eV and series resistance of 7 Ω. The rectification properties after annealing was maintained up to an annealing temperature of 500 °C, but deviated slightly above 500 °C. The uncompensated ionized donor concentration decreased with annealing temperature, which could be attributed to out-diffusion of the 4 H-SiC into the Au/Ni contacts and decrease in bonding due to formation of nickel silicides. We observed the presence of four deep-level defects with energies 0.09, 0.11, 0.16 and 0.65 eV below the conduction band before and after the isochronal annealing up to 600 °C. The conclusion drawn was that annealing did not affect the number of deep-level defects present in Au/Ni/4 H-SiC contacts. The variations in electrical properties of the devices were attributed to the phase transformations and interfacial reactions that occurred after isochronal annealing.

  20. Effects of pressure, temperature and atomic exchanges on phase separation dynamics in Au/Ni(111) surface alloy: Kinetic Monte Carlo study

    Energy Technology Data Exchange (ETDEWEB)

    Zvejnieks, G. [Institute for Solid State Physics, University of Latvia, Kengaraga 8, LV-1063 Riga (Latvia); Ibenskas, A., E-mail: ibenskas@pfi.lt [Center for Physical Sciences and Technology, Semiconductor Physics Institute, Gostauto 11, LT-01108 Vilnius (Lithuania); Tornau, E.E. [Center for Physical Sciences and Technology, Semiconductor Physics Institute, Gostauto 11, LT-01108 Vilnius (Lithuania)

    2015-11-15

    Instability of the Au/Ni(111) surface alloy is studied in different CO gas pressure, p, and temperature limits using kinetic Monte Carlo simulations. We analyze the reaction front dynamics and formation of Au clusters using the model which takes into account surface adatom pair and three-body interactions, CO adsorption and desorption, catalytic carbonyl formation reaction, Au and Ni adatom diffusion and their concerted exchange. Variation of interaction parameters allows us to identify three possible reaction front propagation limits with different pressure dependencies: (i) slow channel-like flow in agreement with experimental data [1] (step flow rate, R, increases with p), (ii) intermediate regime (weak p–dependence), and (iii) fast homogeneous flow (R decreases with p). We find that only Au–Ni exchange, contrary to both Ni–CO and Au–CO exchanges, significantly reduces the number of screened Ni atoms inside the Au clusters and stimulates the occurrence of Ni-free Au clusters. The size of Au islands depends on both pressure and temperature. At a fixed temperature it decreases with pressure due to an increased step flow rate. In the high temperature limit, despite the step flow rate exponential increase with temperature, the cluster size increases due to an enhanced Au mobility. - Highlights: • Kinetic Monte Carlo study of Au–Ni surface alloy instability to CO pressure and temperature. • Three reaction front propagation regimes. • In channel-like regime, the step flow rate increases with CO pressure as in experiment. • Ni-free Au islands are obtained when Au-Ni adatom exchange mechanism is considered. • The size of Au islands decreases with pressure and increases with temperature.

  1. Effects of pressure, temperature and atomic exchanges on phase separation dynamics in Au/Ni(111) surface alloy: Kinetic Monte Carlo study

    International Nuclear Information System (INIS)

    Zvejnieks, G.; Ibenskas, A.; Tornau, E.E.

    2015-01-01

    Instability of the Au/Ni(111) surface alloy is studied in different CO gas pressure, p, and temperature limits using kinetic Monte Carlo simulations. We analyze the reaction front dynamics and formation of Au clusters using the model which takes into account surface adatom pair and three-body interactions, CO adsorption and desorption, catalytic carbonyl formation reaction, Au and Ni adatom diffusion and their concerted exchange. Variation of interaction parameters allows us to identify three possible reaction front propagation limits with different pressure dependencies: (i) slow channel-like flow in agreement with experimental data [1] (step flow rate, R, increases with p), (ii) intermediate regime (weak p–dependence), and (iii) fast homogeneous flow (R decreases with p). We find that only Au–Ni exchange, contrary to both Ni–CO and Au–CO exchanges, significantly reduces the number of screened Ni atoms inside the Au clusters and stimulates the occurrence of Ni-free Au clusters. The size of Au islands depends on both pressure and temperature. At a fixed temperature it decreases with pressure due to an increased step flow rate. In the high temperature limit, despite the step flow rate exponential increase with temperature, the cluster size increases due to an enhanced Au mobility. - Highlights: • Kinetic Monte Carlo study of Au–Ni surface alloy instability to CO pressure and temperature. • Three reaction front propagation regimes. • In channel-like regime, the step flow rate increases with CO pressure as in experiment. • Ni-free Au islands are obtained when Au-Ni adatom exchange mechanism is considered. • The size of Au islands decreases with pressure and increases with temperature

  2. A detailed study of Au-Ni bimetal synthesized by the phase separation mechanism for the cathode of low-temperature solid oxide fuel cells

    Science.gov (United States)

    Yang, Tao; Rodrigues de Almeida, Carlos Manuel; Ramasamy, Devaraj; Almeida Loureiro, Francisco José

    2014-12-01

    A facile co-reduction and annealing synthesis route of nanospheric particles of Au-Ni bimetal with adjustable composition was developed. In a typical synthesis, a direct co-reduction of HAuCl4.4H2O and NiCl2 in aqueous solution was performed with the assistance of reductive NaBH4 and an anionic surfactant sodium dodecyl sulfate (SDS) functioned as the structure-directing agent. Ultrasonic mixing was used at the same time to control the size of the particles. The morphology, microstructure and the state of the surface atoms were analyzed in detail. These nanospheres showed enhanced electrocatalytic activity towards oxygen reduction reaction than that of pure Au nanoparticles, demonstrated in the low temperature SOFC as cathode. The maximum power density generated is 810 mW cm-2 at 550 °C. This is a promising route of taking advantages the Phase Separation Mechanism to greatly reduce the use of noble metals in the ORR field without sacrificing the electrocatalytic activity.

  3. George Pólya – Educator Extraordinaire

    Indian Academy of Sciences (India)

    IAS Admin

    Mathematics is not a spectator sport. To understand mathematics means – to be able to do mathematics. And what does it mean doing mathematics? In the first place it means to be able to solve mathematical problems. • A mathematics teacher is a midwife to ideas. • What the teacher says in the class is not unimportant but ...

  4. Relationship between partial and average atomic volumes of components in Au-Ni alloys%Au-Ni合金中组元的平均原子体积和偏摩尔体积的关系

    Institute of Scientific and Technical Information of China (English)

    谢佑卿

    2011-01-01

    在系统合金科学框架中建立有关无序合金的平均摩尔性质(体积和势能)的函数.通过对这些函数进行推导,可以得到平均摩尔体积函数、偏摩尔体积函数及派生出与成分相关的函数.在组元的偏摩尔性质和平均摩尔性质之间的普适方程、差分方程、在偏摩尔性质和平均摩尔性质之间不同参数的约束方程和普适的Gibbs-Duhem公式.可以证明从合金平均摩尔性质的不同函数计算的偏摩尔性质是相等的,但总体来说偏摩尔性质不等于给定组元的平均摩尔性质,即偏摩尔性质不能代表相应组元的摩尔性质.通过计算Au-Ni系中组元的偏摩尔体积和平均原子体积以及合金的平均原子体积,证明所建立的公式和函数的正确性.%In the framework of systematic science of alloys,the average molar property (volume and potential energy) functions of disordered alloys were established.From these functions,the average molar property functions,partial molar property functions,derivative functions with respect to composition,general equation of relationship between partial and average molar properties of components,difference equation and constraining equation of different values between partial and average molar properties,as well as general Gibbs-Duhem formula were derived.It was proved that the partial molar properties calculated from various combinative functions of average molar properties of alloys are equal,but in general,the partial molar properties are not equal to the average molar properties of a given component.This means that the partial molar properties cannot represent the corresponding properties of the component.All the equations and functions established in this work were proved to be correct by calculating the results of partial and average atomic volumes of components as well as average atomic volumes of alloys in the Au-Ni system.

  5. George Pólya & Problem Solving ... An Appreciation

    Indian Academy of Sciences (India)

    IAS Admin

    things to say to the teacher of mathematics. Here are .... with no success, leading Jacques (also known as Jakob). Bernoulli to .... ing]: first and foremost, it should teach young people to. THINK. ... \\Teaching to think" means that the teacher.

  6. lya's One Theorem with 100 Pages of Applications

    Indian Academy of Sciences (India)

    IAS Admin

    combinatorial method which led to unexpected applications to diverse ... permutations of D, we define an equivalence of elements ... transformations affect X. The identity, of course, fixes .... the order of a finite group. ... first to use the notion.

  7. Some G Pólya Gems from Complex Analysis

    Indian Academy of Sciences (India)

    IAS Admin

    (Remember that the zeros of an analytic function are isolated.) In order to really get into the spirit of ... These two examples have three things in common: 1. The power ... The author finds this result rather strange because on the one hand, with ...

  8. SUBSTITUED COUMARINS Hülya Çelik Onar1*and Begüm

    African Journals Online (AJOL)

    the most widely applied for the synthesis of coumarins due to simple reaction conditions and good yields. Nowadays ... oxalic acid (10 mol%) was heated to 80 oC till completion of the reaction (monitored using. TLC). Then, the .... coumarin anticoagulants via hetero-Diels–Alder cycloaddition Tetrahedron Asymm. 2001,.

  9. Implementing thinking aloud pair and Pólya problem solving strategies in fractions

    Science.gov (United States)

    Simpol, N. S. H.; Shahrill, M.; Li, H.-C.; Prahmana, R. C. I.

    2017-12-01

    This study implemented two pedagogical strategies, the Thinking Aloud Pair Problem Solving and Pólya’s Problem Solving, to support students’ learning of fractions. The participants were 51 students (ages 11-13) from two Year 7 classes in a government secondary school in Brunei Darussalam. A mixed method design was employed in the present study, with data collected from the pre- and post-tests, problem solving behaviour questionnaire and interviews. The study aimed to explore if there were differences in the students’ problem solving behaviour before and after the implementation of the problem solving strategies. Results from the Wilcoxon Signed Rank Test revealed a significant difference in the test results regarding student problem solving behaviour, z = -3.68, p = .000, with a higher mean score for the post-test (M = 95.5, SD = 13.8) than for the pre-test (M = 88.9, SD = 15.2). This implied that there was improvement in the students’ problem solving performance from the pre-test to the post-test. Results from the questionnaire showed that more than half of the students increased scores in all four stages of the Pólya’s problem solving strategy, which provided further evidence of the students’ improvement in problem solving.

  10. The effect of the clove essential oil to the production and quality of lyaing hens eggs

    Directory of Open Access Journals (Sweden)

    Henrieta Arpášová

    2017-05-01

    Full Text Available The aim of this study was to determinate the effect of the clove (Syzygium aromaticum essential oil to the egg production parameters and egg quality of laying hens. A total of 40 Lohmann Brown laying hens were divided into 4 groups (n = 10. The laying hens were fed 20 weeks ad libitum. The control group was fed with complete feed mixtures without additives. The first group of hens was fed a diet with complete feed mixtures with 0.3 mg.kg-1 of clove essential oil. The second group of hens was fed a diet with complete feed mixtures with 0.6 mg.kg-1 of clove oil and the third group of hens was fed a diet with complete feed mixtures with 1 mg.kg-1 of clove oil. Egg production, egg weight (g, specific egg weight, albumen weight (g, albumen index, Haugh Units (HU, yolk weight (g, yolk index, yolk color (HLR were studied. The results show that the addition of clove oil, especially in the group of laying hens with the addition of 1 mg.kg-1 clove oil had no significantly different (P>0.05 to the egg production (the order of the groups: 90.3; 91.8; 91.3; 92.6 %. In egg weight were found no significant differences between groups. The addition of 1 mg.kg-1 clove oil had significant (P>0.05 influenced the albumen index and the addition of 0.6 mg.kg-1 and 1 mg.kg-1 clove oil had significant (P>0.05 influenced Haugh units. In the control group was found not significant (P>0.05 different in yolk weight compared with other groups. In the other parameters of egg quality (albumen weight, yolk index, yolk colour with the addition of clove oil were found no significant differences between groups.

  11. Brazing of zirconia to titanium using Ag-Cu and Au-Ni filler alloys

    Directory of Open Access Journals (Sweden)

    Jean S. Pimenta

    2013-12-01

    Full Text Available Advanced ceramic is usually joined to metal by the well-known direct brazing process, where costly active filler alloys can be considered a limitation. Brazing using active-metal-free filler alloy as insert between the joint components is an attempt to overcome it. The active metal diffusion from the titanium member through the bulk of molten filler to the ceramic was responsible to produce an active filler alloy in loco and promote reduction of the zirconium oxide to improve wetting on the ceramic surface. Unalloyed titanium was joined in a high-vacuum furnace (<3x10-5 mbar to yttria-tetragonal zirconia polycristals (Y-TZP and zirconia partially stabilized with magnesia (Mg-PSZ, where commercial fillers Ag-28Cu and Au-18Ni with respective thermal cycles were evaluated. Helium gas leak detection test was performed at the ceramic/metal interface at room temperature; samples from reliable vacuum tight joints were examined by microstructural analysis techniques and energy dispersive X-ray analysis at the joint cross-section. Tight joints were produced with eutectic Ag-Cu filler, revealing an intermetallic layer and a dark reaction layer near the ceramic surface; titanium diffusion was efficient for superficial chemical interactions between individual components. Brazing joints were also tested using three-point flexure testing.

  12. Koolitusel osalemise seotus ametipositsiooniga = Participation in training in connection with occupational position / Auni Tamm, Margarita Kazjulja

    Index Scriptorium Estoniae

    Tamm, Auni

    2009-01-01

    Statistikaameti poolt 1997. ja 2007. aastal läbi viidud täiskasvanute koolituse uuringute tulemuste võrdlus. Artiklis on vaatluse all eri ametipositsiooniga töötajate osalemine tasemeõppes ja täienduskoolitustel

  13. Au-Ni nanoparticles: Phase diagram prediction, synthesis, characterization, and thermal stability

    Czech Academy of Sciences Publication Activity Database

    Sopoušek, J.; Kryštofová, A.; Premovic, M.; Zobač, O.; Postlerová, S.; Brož, P.; Buršík, Jiří

    2017-01-01

    Roč. 58, SEP (2017), s. 25-33 ISSN 0364-5916 R&D Projects: GA ČR(CZ) GA17-12844S; GA ČR(CZ) GA17-15405S Institutional support: RVO:68081723 Keywords : nanoalloy * CALPHAD * phase diagram Subject RIV: BJ - Thermodynamics OBOR OECD: Thermodynamics Impact factor: 1.600, year: 2016

  14. Facet-controlled phase separation in supersaturated Au-Ni nanoparticles upon shape equilibration

    Czech Academy of Sciences Publication Activity Database

    Herz, A.; Friák, Martin; Rossberg, D.; Hentschel, M.; Theska, F.; Wang, D.; Holec, D.; Šob, Mojmír; Schneeweiss, Oldřich; Schaaf, P.

    2015-01-01

    Roč. 107, č. 7 (2015), art.n. 073109 ISSN 0003-6951 Institutional support: RVO:68081723 Keywords : GENERALIZED GRADIENT APPROXIMATION * NANOPOROUS GOLD NANOPARTICLES * AUGMENTED-WAVE METHOD * ELASTIC-CONSTANTS * BILAYER * NICKEL Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.142, year: 2015

  15. RENDS AND ISSUES IN DISTANCE EDUCATION: International Perspectives, Second Edition Edited by Lya Visser, Yusra Visser, Ray Amirault & Michael Simonson

    Directory of Open Access Journals (Sweden)

    Reviewed by Dilek ALTUNAY

    2013-07-01

    Full Text Available Over the last decade, the field of distance education (and e-learning has substantially strengthened and assumed a more international scope. There has been an impressive growth in the conceptual, empirical and experiential foundations of the field. Trends and Issues in Distance Education: International Perspectives (2nd Ed captures a representative snapshot of the breadth of current global trends and issues in distance education theory, research, and practice. Through 21 chapters (from over 30 international authors, the book documents new developments in distance education scholarship and practice, presenting a diverse set of viewpoints on the trends and issues affecting this increasingly central discipline. The book is for researchers, practitioners, and students. Chapters speak to the many creative ways in which distance education addresses learning and human development needs around the world. They focus on distance education in dissimilar settings that extend beyond the limitations of the dominating paradigms of the highly developed economies. Contributing authors touch upon conceptual as well as practical issues. They critically reflect on both large- and small-scale distance education initiatives, discussing the use of everything from the most advanced technologies (e.g., 3-D computing to the most rudimentary technologies (e.g., wind-up radios (Quated Amazon Pages This book makes a contribution to the field of distance education by offering a comprehensive overview and analysis of the current trends and issues in distance education. In addition, the book is well-organized and coherent in terms of presentation. The reader is guided by section editors who provides introduction to the sectio

  16. Huge Inverse Magnetization Generated by Faraday Induction in Nano-Sized Au@Ni Core@Shell Nanoparticles.

    Science.gov (United States)

    Kuo, Chen-Chen; Li, Chi-Yen; Lee, Chi-Hung; Li, Hsiao-Chi; Li, Wen-Hsien

    2015-08-25

    We report on the design and observation of huge inverse magnetizations pointing in the direction opposite to the applied magnetic field, induced in nano-sized amorphous Ni shells deposited on crystalline Au nanoparticles by turning the applied magnetic field off. The magnitude of the induced inverse magnetization is very sensitive to the field reduction rate as well as to the thermal and field processes before turning the magnetic field off, and can be as high as 54% of the magnetization prior to cutting off the applied magnetic field. Memory effect of the induced inverse magnetization is clearly revealed in the relaxation measurements. The relaxation of the inverse magnetization can be described by an exponential decay profile, with a critical exponent that can be effectively tuned by the wait time right after reaching the designated temperature and before the applied magnetic field is turned off. The key to these effects is to have the induced eddy current running beneath the amorphous Ni shells through Faraday induction.

  17. Huge Inverse Magnetization Generated by Faraday Induction in Nano-Sized Au@Ni Core@Shell Nanoparticles

    Directory of Open Access Journals (Sweden)

    Chen-Chen Kuo

    2015-08-01

    Full Text Available We report on the design and observation of huge inverse magnetizations pointing in the direction opposite to the applied magnetic field, induced in nano-sized amorphous Ni shells deposited on crystalline Au nanoparticles by turning the applied magnetic field off. The magnitude of the induced inverse magnetization is very sensitive to the field reduction rate as well as to the thermal and field processes before turning the magnetic field off, and can be as high as 54% of the magnetization prior to cutting off the applied magnetic field. Memory effect of the induced inverse magnetization is clearly revealed in the relaxation measurements. The relaxation of the inverse magnetization can be described by an exponential decay profile, with a critical exponent that can be effectively tuned by the wait time right after reaching the designated temperature and before the applied magnetic field is turned off. The key to these effects is to have the induced eddy current running beneath the amorphous Ni shells through Faraday induction.

  18. Huge Inverse Magnetization Generated by Faraday Induction in Nano-Sized Au@Ni Core@Shell Nanoparticles

    Science.gov (United States)

    Kuo, Chen-Chen; Li, Chi-Yen; Lee, Chi-Hung; Li, Hsiao-Chi; Li, Wen-Hsien

    2015-01-01

    We report on the design and observation of huge inverse magnetizations pointing in the direction opposite to the applied magnetic field, induced in nano-sized amorphous Ni shells deposited on crystalline Au nanoparticles by turning the applied magnetic field off. The magnitude of the induced inverse magnetization is very sensitive to the field reduction rate as well as to the thermal and field processes before turning the magnetic field off, and can be as high as 54% of the magnetization prior to cutting off the applied magnetic field. Memory effect of the induced inverse magnetization is clearly revealed in the relaxation measurements. The relaxation of the inverse magnetization can be described by an exponential decay profile, with a critical exponent that can be effectively tuned by the wait time right after reaching the designated temperature and before the applied magnetic field is turned off. The key to these effects is to have the induced eddy current running beneath the amorphous Ni shells through Faraday induction. PMID:26307983

  19. Süüteovahendi konfiskeerimise eesmärk ja õiguslik olemus ning selle põhiseaduslik õigustus. Riigikohtu üldkogu otsus asjas 3-1-1-37-07 / Andres Parmas

    Index Scriptorium Estoniae

    Parmas, Andres, 1977-

    2008-01-01

    Riigikohtu lahendist 3-1-1-37-07 (Toomas Tiiki kaitsja vandeadvokaadi abi Anti Aasmaa kassatsioon Viru Ringkonnakohtu 22. märtsi 2007. a kohtuotsuse peale kriminaalasjas Toomas Tiiki süüdistuses KarS § 424 järgi)

  20. Requalifying the Built Environment: Challenges and Responses. By Roderick J. Lawrence, Hülya Turgut, Peter Kellett, Hogrefe, 2012; 232 pages. Price: 54,95€, ISBN 978-0-88937-430-0

    Directory of Open Access Journals (Sweden)

    Shu-Kun Lin

    2013-01-01

    Full Text Available In recent decades, significant financial and professional resources have been invested in urban regeneration, housing renovation, and the revitalization of old neighborhoods, with considerable impacts on the social, physical, and economic structure of cities and their inhabitants. The first objective of this volume is to present the key issues related to these changes, which were discussed at an international symposium of experts organized by the International Association for People-Environment Studies and Housing and CSBE (Culture and Space in the Built Environment Networks in Istanbul. The second objective is to show how concepts and methods in the field of people-environment studies can be successfully applied to study complex questions related to the revitalization of the built environment, both at the small scale of specific buildings and at the larger scale of neighborhoods.

  1. HATA TÜRÜ VE ETKİLERİ ANALİZİ (FMEA TEKNİĞİNİN MOBİLYA ENDÜSTRİSİNE YÖNELİK UYGULAMASI

    Directory of Open Access Journals (Sweden)

    Yüksel TAŞ

    2013-01-01

    Full Text Available FMEA (Hata Türü ve Etkileri Analizi tekniği, hataları ortaya çıkmadan önlemeye yönelik çok güçlü bir sayısal analiz tekniğidir. Bu çalışmada, FMEA çeşitlerinden biri olan proses FMEA çalışmasının mobilya endüstrisine yönelik örnek bir uygulaması yapılmıştır. Araştırma CNC makinelere sahip, kalite güvencesine yönelen bir işletmede gerçekleştirilmiş, uygulama sonucu karşılaşılan hata türleri ile ilgili nedenlerin yok edilmesine veya azaltılmasına, prosesi iyileştirecek değişikliklerin belirlenmesine ve uygulanmasına çalışılmıştır. Araştırma sonucunda, olası hata türleri ortaya çıkmış ve bu hata türleri tanımlanmıştır. Böylece benzer işletmeler ve çalışanlar için hata türleri ile karşılaşıldığında nasıl bir yol izleneceği ve hangi yöntemlerin uygulanacağının farkındalığı sağlanmıştır. İşletme için hata oluşumunu önleme yönelik rehber sayılabilecek nitelikteki örnek faaliyetler yapılmış ve kalitesizlik maliyetlerinin düşürülmesi sağlanmıştır. Özetle mobilya işletmesinde FMEA yöntemi uygulamasında uygulama öncesi ve sonrası değerler karşılaştırıldığında; hata türlerinde, sayı, şiddet ve olasılık olarak 1 ile 6 kat arasında azalma gerçekleşmiş, işletmede kalite güvencesinin sağlanmasına yönelik önemli bir gelişme sağlanmıştır.

  2. The Agatston Urban Nutrition Initiative: Working to Reverse the Obesity Epidemic through Academically Based Community Service

    Science.gov (United States)

    Johnston, Francis E.

    2009-01-01

    The Agatston Urban Nutrition Initiative (AUNI) presents a fruitful partnership between faculty and students at a premier research university and members of the surrounding community aimed at addressing the problem of childhood obesity. AUNI uses a problem-solving approach to learning by focusing course activities, including service-learning, on…

  3. The Coffee-Milk Mixture Problem Revisited

    Science.gov (United States)

    Marion, Charles F.

    2015-01-01

    This analysis of a problem that is frequently posed at professional development workshops, in print, and on the Web--the coffee-milk mixture riddle--illustrates the timeless advice of George Pólya's masterpiece on problem solving in mathematics, "How to Solve It." In his book, Pólya recommends that problems previously solved and put…

  4. Damages of electrical insulation of cable products used at NPP`s and technique of their detection and operative control; Povrezhdeniya v ehlektricheskoj izolyatsii kabel`nykh izdulij, ehkspluatirue mykh na atomnykh ehlektrostantsiyakh i metody ikh obnaruzheniya i operativnogo kontro lya

    Energy Technology Data Exchange (ETDEWEB)

    Valeev, R S; Filatov, N I

    1994-12-31

    Analysis of possible damages in electrical insulation of cable products under their application at NPP`s is conducted. Basic methods for detecting such damages and rapid control of technical condition of cable products during the operation are considered.

  5. Radiation-induced apoptosis in sensitive and resistant cells isolated from a mouse lymphoma

    International Nuclear Information System (INIS)

    Story, M.D.; Voehringer, D.W.; Malone, C.G.; Hobbs, M.L.; Meyn, R.E.

    1994-01-01

    Cells were isolated from a mouse lymphoma (LY-TH) and grown in vitro. They were susceptible to radiation-induced apoptosis after low doses with the appearance of endonucleolytically fragmented DNA 1 h after irradiation. Four hours after receiving 5 Gy, 80% of the DNA was endonucleolytically cleaved. Apoptosis induction by DNA double-strand break (dsb) formation was more effective compared with induction by single-strand break (ssb) formation. After long-term culturing, LY-TH cultures became refractory to apoptosis. Apoptosis-permissive cells (LY-as, cloned from LY-TH cells) were three times more radiosensitive than clonally expanded apoptosis-refractory cells (LY-ar). Low dose-rate irradiation and maintenance at 25 o C for 5 h postirradiation was sparing in LY-ar but not LY-as cells, suggesting a repair deficiency in LY-as cells. Analysis of dsb rejoining kinetics revealed no difference in the initial phase of dsb rejoining. After 1 h, however, relative dsbs in the LY-as variant increased as endonucleolytic cleavage was initiated. Signalling for radiation-induced apoptosis in LY-as cells was independent of the DNA dsb repair pathway and appeared determined by initial events, whereas in LY-ar cells, because of an inhibition in the apoptotic pathway, survival was enhanced and modifiable by repair processes. (author)

  6. Microfabrication and Magnetic Particle Spectrometry of Magnetic Discs

    NARCIS (Netherlands)

    Löthman, Per Arvid; Janson, T.G.; Klein, Yannick Philippe; Blaudszun, André-René; Ledwig, Michael; Abelmann, Leon

    2017-01-01

    We report on the fabrication of dispersions of Au/Ni81Fe19/Au magnetic discs with two and three micrometer diameter and thickness in the order of hundred nanometers. The magnetisation reversal of the discs was analysed on a time-scale of an hour as well as a few milliseconds to asses their

  7. Ramjets and Ramrockets for Military Applications

    Science.gov (United States)

    1982-03-01

    or auni)from multiple platforms and other operational considerations e-posed in recent XA1(o/nf~ studies should not invalidate the above claim. of...thereby obviating the need for any evaporation time. To ascertain the degree of pre- wix , carbon dioxide (selected because of its denasity similarit7

  8. Task Organizing for Urban Combat

    Science.gov (United States)

    1978-06-09

    IhigIay. This line ocsis•i• of twelve majo forts, nuerous pillbazes, antitank ditches and a cmantiaus barbed wire 29 Nm 0 S IV 04a Rs’wv 5):~ ...... .. I...as the railroad stallion , a &-tadi= and the auni- oipal buildings. These strongpoints were aunanted with varinue types of wire, mines and obstacles

  9. Näidendivõistlusel selgus Eesti viis parimat mereäärset lugu / Teele Tammeorg

    Index Scriptorium Estoniae

    Tammeorg, Teele

    2010-01-01

    Eesti Teatri Agentuur ja SA Tallinn 2011 kuulutasid näidendikonkursi "Mereäärsed lood" võitjateks Martin Alguse "Kontakti", Christian Auni ja Mariann Tihase "Kastis!", Urmas Lennuki "Minu tänav", Katrin Maimiku "Metspardi" ja Mario Pulveri "Fluidumi". "Mereäärsed lood" on rahvusvahelise näidendivõistluse "New Baltic Drama 2011" esimene voor

  10. Sadhana | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Sadhana. Atilla Biyikoglu. Articles written in Sadhana. Volume 37 Issue 2 April 2012 pp 207-222. Enhancement of cell characteristics via baffle blocks in a proton exchange membrane fuel cell · Atilla Biyikoglu Hülya Oztoprak · More Details Abstract Fulltext PDF. In this study, the effects of baffle blocks ...

  11. Ühendatud Balti Ameerika Komitee eestlaste juhtimisel

    Index Scriptorium Estoniae

    2005-01-01

    alates 2005. aasta märtsist, need on : Mati Kõiva ÜBAK president, Lya Karm - esinaine, Erik Puskar - liige, Karl Altau - büroojuhataja. Peamiseks tegevuseks on USA Kongressi saadikutekojas läbi viia esitatud resolutsioon, mis nõuab, et Venemaa vabandaks 1940. aasta Balti riikide okupeerimise pärast

  12. Sadhana | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Sadhana; Volume 37; Issue 2. Issue front cover thumbnail. Volume 37, Issue 2. April 2012, pages 207-318. pp 207-222. Enhancement of cell characteristics via baffle blocks in a proton exchange membrane fuel cell · Atilla Biyikoglu Hülya Oztoprak · More Details Abstract Fulltext PDF. In this study, the effects ...

  13. Application of Normal Family to the Spread Inequality and the Paley ...

    African Journals Online (AJOL)

    In this paper we derive a Paley type inequality for subharmonic functions of order λ,0 < λ≤½ and describe the asymptotic behaviour of the extremal functions near Pòlya peaks. We also give an alternative proof for the spread inequality using a non-asymptotic method via - a normal family of δ -subharmonic functions.

  14. Egy tanúságtevő hitvalló, szolgáló, tudományos és papi pálya lezárult: Petrasevics Nikefor József eperjesi görög katolikus kanonok és tudományos kutató emlékére (1915–2013 - Passed a Wittness of the Faith, Scientist, a Servant of The Lord, True Priest: Nicefor Petrashevich (1915–2013, canon of the Preshov Greek Catholic Eparchy

    Directory of Open Access Journals (Sweden)

    FÖLDVÁRI, Sándor

    2014-03-01

    Full Text Available Decease of the witness of the Faith, a servant of the Lord and a famous researcher of the religious folklore: Nicefor Joseph Petrashevich (1915–2013 distinguished member of the Capitol of Preshov Greek Catholic Eparchy Born in Čukalovce, East-Slovakia (then Csukalóc, Upper-Hungary in 1915 as the sixth of the eleven children in the family of a Greek Catholic bishop, he was inspired by his father and elder brother who served the Lord. He studied in the high school (gymnasium of the Cistercian Order in Eger (Northern Hungary which provided its pupils with knowledge and deep faith. He became a choir-minister of the Uzghorod Bishopric Basilica where he turned to the examination of folklore traditions reflected in the liturgical chants. Apparently, it was his calling and his findings on the Byzantine chants contributed significantly to the understanding of religious folklore. He was known as a gifted composer and singer too. The Greek Catholic Church was banned in the Soviet Union which obtained Subcarpathia after the World War II, and this church was oppressed in Slovakia as well, so he faced a dilemma: to convert to the Ortodox (Pravoslav Christianity and live free, or to remain faithful to the Catholic Church and be persecuted. Moreover, he was a coelebs, a priest who did not have a wife (despite the fact that Greek Catholic priests are allowed to have families. Consequently, he could have been elected as bishop, as the higher ranks in the Byzantine Churches are open for monks. The communist authorities offered Pope Nicefor the episcopate of the Slovak Ortodox Church, if he converted to the Ortodoxy. He refused it: “my head does not accept the mithra (bishops’ crone by leaving my Catholic faith” –he said. As a result, he was imprisoned for more than two years in Slovakia. Later he came to Hungary where could not serve as a parochial priest, but worked as cantor or helping pope in various places and in centres of pilgrimage where performed the liturgy in Church Slavonic which he sang excellently. Continuing his researches in the folk sings in the liturgy and the local traditions of the liturgical chants, he gained a small grant of the Soros Foundation in 1986 and delivered lectures for two semesters at the Department of the Folklore at the Eötvös University in Budapest in 1988–89. His papers have been par tia l ly published, but most of t hem are still preserved as manuscripts in the Institute of Musicology at the Hungarian Academy of Sciences, or even in unknown places worldwide, as he sent his works to his brothers-in-faith to the United States. In his eighties, instead of enjoying the golden days of ageing, he moved to Slovakia in order to serve as a pastor who spoke both Slovakian and Hungarian as mother tongues. He was buried in Szikszó, Hungary where the Greek Catholic Bishop of Preshov and approximately forty popes from Ukraine, Hungary and Slovakia commemorated him on 20 July 2013. Church historians and folklorists honoured his memory as a researcher with a conference on 4 October 2013 in Szikszó. Proceedings are to be published next year. A memorial website about him is open for bloggers: https://www.facebook.com/groups/Petrasevic.Nikefor.spomienky

  15. Astro research fellowship: the role of bcl-2 and glutathione in an antioxidant pathway to prevent radiation-induced apoptosis

    International Nuclear Information System (INIS)

    Vlachaki, Maria T.; Meyn, Raymond E.

    1998-01-01

    Purpose: The expression of the bcl-2 proto-oncogene has been associated with resistance to radiation-induced apoptosis. There is evidence that the bcl-2 protein acts in an antioxidant pathway to block the effects of reactive oxygen species that mediate apoptosis possibly by increasing the levels of intracellular glutathione. Our hypothesis is that pretreatment of radiation-sensitive cells, known to lack bcl-2 expression, with antioxidants will reduce radiation-induced apoptosis. For this purpose, the apoptotic response to radiation and the intracellular levels of GSH were tested before and after pretreatment with antioxidants in two murine lymphoma cell lines, a radiation-resistant, bcl-2- expressing (LY-ar) line and a radiation-sensitive, non-bcl-2-expressing (LY-as) line. Methods and Materials: LY-ar and LY-as cells were irradiated at 0,1,2,3, and 4 hours before collection. The intracellular levels of reduced (GSH) and oxidized (GSSG) glutathione were determined by the use of the fluorescent dye o-phthalaldehyde. LY-as cells were treated with GSH ethyl-ester for 1 and 2 hours after irradiation. Apoptotic response was measured by the DNA fragmentation assay. The radiation dose was 2.5 Gy. Results: After irradiation, the apoptotic rate of LY-ar and LY-as cells was 10-20% and 50-70% respectively. LY-ar cells had higher intracellular GSH and GSSG levels compared to LY-as cells by 69.9% and 91.9% respectively and the GSH/GSSG ratio in LY-ar and LY-as cells was 15.09 and 17.09 respectively. GSH levels did not change during the first 2 hours after irradiation; however, there was a 49% and 84% reduction at 3 and 4 hours after irradiation, respectively, times at which the LY-as cells have already fragmented their DNA. Treatment of LY-as cells with GSH ethyl-ester at a concentration of 7 mM for 1 and 2 hours resulted in 70% and 231% increases in the intracellular GSH levels respectively. Treatment of LY-as cells with GSH ethyl-ester for 1 and 2 hours also conferred a 25

  16. Selection of Dogs for Land Mine and Booby Trap Detection Training. Volume I

    Science.gov (United States)

    1976-09-01

    Sarcoptes scabier, the 12 causes of demodectic and sarcoptic mange , respectively, may be speci- fically diagnosed by microscopic examination of skin scrapings...8217 UNCLASSIFIED 10 - SELECTION OF DOGS FOR LAND MINE AND BOOBY TRAP DETECTION TRAINING (U) FINAL TECHNICAL REPORT VOLUME i by Daniel S. Mitchell...1 ...... I " SELECTION OF DOGS k- FOR LAND MINE AND OOlBY TRAP DETECTION TRAINING * Contract -3C p t DAA1WC.LYA by , /ODaniel S

  17. Aspergillus fumigatus Does Not Require Fatty Acid Metabolism via Isocitrate Lyase for Development of Invasive Aspergillosis▿

    OpenAIRE

    Schöbel, Felicitas; Ibrahim-Granet, Oumaïma; Avé, Patrick; Latgé, Jean-Paul; Brakhage, Axel A.; Brock, Matthias

    2006-01-01

    Aspergillus fumigatus is the most prevalent airborne filamentous fungus causing invasive aspergillosis in immunocompromised individuals. Only a limited number of determinants directly associated with virulence are known, and the metabolic requirements of the fungus to grow inside a host have not yet been investigated. Previous studies on pathogenic microorganisms, i.e., the bacterium Mycobacterium tuberculosis and the yeast Candida albicans, have revealed an essential role for isocitrate lyas...

  18. Methodology identification in mass disasters

    OpenAIRE

    Ampudia García, Omar

    2014-01-01

    Major disasters in Perul ack from a treatment plan and adapt to the current reality. Were rare and limited to natural disasters such as major earthquakes, floods, torrential rains, erupting volcanoes, and so on.At first these disasters were limited to certain geographic areas ingeneral,but with the advancement of science and technology these events have soared alarming lyas rail crashes, plane crashes, car crashes going at high speed,and if we add the attacks by fundamentalist groups with car...

  19. 1 r urT log ),( r t lim ),( ) ( , urT urrT r r

    African Journals Online (AJOL)

    Preferred Customer

    dθ where u+(z) = max(u(z), 0). The lower order λ of u is given by λ = lim r. urT log. ),(. A sequence {rn} of positive numbers is said to be a sequence of Pólya peaks for T(r, u) of order λ > 0 if there is a sequence {∈n}, ∈n > 0 such that ∈n → 0.

  20. Constraining the Intergalactic and Circumgalactic Media with Lyman-Alpha Absorption

    Science.gov (United States)

    Sorini, Daniele; Onorbe, Jose; Hennawi, Joseph F.; Lukic, Zarija

    2018-01-01

    Lyman-alpha (Ly-a) absorption features detected in quasar spectra in the redshift range 02Mpc, the simulations asymptotically match the observations, because the ΛCDM model successfully describes the ambient IGM. This represents a critical advantage of studying the mean absorption profile. However, significant differences between the simulations, and between simulations and observations are present on scales 20kpc-2Mpc, illustrating the challenges of accurately modeling and resolving galaxy formation physics. It is noteworthy that these differences are observed as far out as ~2Mpc, indicating that the `sphere-of-influence' of galaxies could extend to approximately ~20 times the halo virial radius (~100kpc). Current observations are very precise on these scales and can thus strongly discriminate between different galaxy formation models. I demonstrate that the Ly-a absorption profile is primarily sensitive to the underlying temperature-density relationship of diffuse gas around galaxies, and argue that it thus provides a fundamental test of galaxy formation models. With near-future high-precision observations of Ly-a absorption, the tools developed in my thesis set the stage for even stronger constraints on models of galaxy formation and cosmology.

  1. The role of BCL-2 and glutathione in an antioxidant pathway to prevent radiation-induced apoptosis

    International Nuclear Information System (INIS)

    Vlachaki, Maria T.; Meyn, Raymond E.

    1997-01-01

    Objective: The expression of the bcl-2 gene has been associated with resistance to radiation induced apoptosis. There is evidence that the bcl-2 protein acts in the antioxidant pathways to block the effects of reactive oxygen spieces that mediate apoptosis possibly by increasing the levels of intracellular glutathione. Our hypothesis is that pretreatment of radiation-sensitive cells, known to lack bcl-2 expression, with antioxidants will reduce radiation-induced apoptosis. For this purpose, the apoptotic response to radiation and the intracellular levels of glutathione were tested before and after pretreatment with antioxidants in two murine lymphoma cell lines, a radiation resistant-bcl-2 expressing (Ly-ar) line and a radiation sensitive (Ly-as) line. Methods and Materials: Ly-ar and Ly-as cells were irradiated at 0,1,2,3 and 4 hours before collection. The intracellular levels of reduced (GSH) and oxidized (GSSG) glutathione were determined by the use of the fluorescent dye ophthalaldehyde. Ly-as cells were pretreated with dihydrolipoic acid and lipoamide for 1 hour before irradiation. Apoptosis response was measured by the DNA fragmentation assay. The radiation dose was 2.5 Gy. Results: After irradiation, the apoptotic rate of Ly-ar and Ly-as cells is 11-19% and 66-87% respectively. Ly-ar cells have higher intracellular GSH and GSSG levels compared to Ly-as cells by 69.9% and 91.9% respectively and the GSH/GSSG ratio in Ly-ar and Ly-as cells is 17.09 and 15.09 respectively (a difference of 13.25%). GSH levels do not change during the first three hours after irradiation; however there is a 46% reduction at four hours after irradiation, a time at which the Ly-as cells have already fragmented their DNA. Pretreatment of cells with dihydrolipoic acid or lipoamide at concentrations of 4mM and 2mM respectively was toxic and resulted in cell death in the absence of irradiation. Conclusions: GSH and GSSG levels are elevated in radiation-resistant murine lymphoma cells

  2. Phase-field model and its numerical solution for coring and microstructure evolution studies in alloys

    Science.gov (United States)

    Turchi, Patrice E. A.; Fattebert, Jean-Luc; Dorr, Milo R.; Wickett, Michael E.; Belak, James F.

    2011-03-01

    We describe an algorithm for the numerical solution of a phase-field model (PFM) of microstructure evolution in alloys using physical parameters from thermodynamic (CALPHAD) and kinetic databases. The coupled system of PFM equations includes a local order parameter, a quaternion representation of local crystal orientation and a species composition parameter. Time evolution of microstructures and alloy composition is obtained using an implicit time integration of the system. Physical parameters in databases can be obtained either through experiment or first-principles calculations. Application to coring studies and microstructure evolution of Au-Ni will be presented. Prepared by LLNL under Contract DE-AC52-07NA27344

  3. Methods for studying short-range order in solid binary solutions

    International Nuclear Information System (INIS)

    Beranger, Gerard

    1969-12-01

    The short range order definition and its characteristic parameters are first recalled. The different methods to study the short range order are then examined: X ray diffusion, electrical resistivity, specific heat and thermoelectric power, neutron diffraction, electron spin resonance, study of thermodynamic and mechanical properties. The theory of the X ray diffraction effects due to short range order and the subsequent experimental method are emphasized. The principal results obtained from binary Systems, by the different experimental techniques, are reported and briefly discussed. The Au-Cu, Li-Mg, Au-Ni and Cu-Zn Systems are moreover described. (author) [fr

  4. Synthesis of a novel Au nanoparticles decorated Ni-MOF/Ni/NiO nanocomposite and electrocatalytic performance for the detection of glucose in human serum.

    Science.gov (United States)

    Chen, Jingyuan; Xu, Qin; Shu, Yun; Hu, Xiaoya

    2018-07-01

    A nonenzymatic glucose electrochemical sensor was constructed based on Au nanoparticles (AuNPs) decorated Ni metal-organic-framework (MOF)/Ni/NiO nanocomposite. Ni-MOF/Ni/NiO nanocomposite was synthesized by one-step calcination of Ni-MOF. Then AuNPs were loaded onto the Ni-based nanocomposites' surface through electrostatic adsorption. Through characterization by transmission electron microscopy (TEM), high resolution TEM (HRTEM) and energy disperse spectroscopy (EDS) mapping, it is found that the AuNPs were well distributed on the surface of Ni-based nanocomposite. Cyclic voltammetric (CV) study showed the electrocatalytic activity of Au-Ni nanocomposite was highly improved after loading AuNPs onto it. Amperometric study demonstrated that the Au-Ni nanocomposites modified glassy carbon electrode (GCE) exhibited a high sensitivity of 2133.5 mA M -1 cm -2 and a wide linear range (0.4-900 μM) toward the oxidation of glucose with a detection limit as low as 0.1 μM. Moreover, the reproducibility, selectivity and stability of the sensor all exhibited outstanding performance. We applied the as-fabricated high performance sensor to measure the glucose levels in human serum and obtained satisfactory results. It is believed that AuNPs decorated Ni MOF/Ni/NiO nanocomposite provides a new platform for developing highly performance electrochemical sensors in practical applications. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. The effects of arsenic or the combination of arsenic and radiation exposure is enhanced through the overexpression of the GSTO family member p28

    International Nuclear Information System (INIS)

    Giri, U.; Story, M.D.; Terry, N.H.A.; Giri, D.K.; Calkins, P.R.

    2003-01-01

    Full text: p28 is a member of the GST omega superfamily and has dehydroascorbate reductase, GST, and glutaredoxin activities. Furthermore, p28 is the rate-limiting enzyme in the bio-transformation of arsenic. The monomethyl arsenous reducatase activity of p28 produces dimethylarseniate, the most toxic form of arsenic. We investigated how p28 modulated arsenic cellular sensitivity in two mammalian models: 1) in LY-ar and LY-as cells where p28 is over-expressed and not expressed, respectively; and 2) in stably transfected A549 cells where p28 is over-expressed via a CMV promoter. The LY-ar mouse lymphoma cell line is radio and chemo-resistant and apoptosis refractory, whereas the parental cell line, LY-as, is radiosensitive and apoptotically permissive. In addition, we studied the effect of arsenic as a radiosensitizer in both cell systems. In LY-ar cells arsenic induced a dose- and time- dependent increase in apoptosis, which is comparable to that seen in LY-as cells. Arsenic plus 2.5Gy radiation induced apoptosis in LY-ar cells, which was more than additive. Survival in LY-ar cells was reduced to that of LY-as cells as well as p28 overexpression induced G2/M arrest in A549 cells and the combination of radiation with arsenic decreased the clonogenic survival of both the A549 and A549-p28 cells but the effect is more pronounced in the A549-P28 cell line. A549 and A549-p28 cells did not show a differential response to Taxol, which induces G2/M arrest and cell death via an inhibition of tubulin depolarization. Arsenic modulated the level of reduced GSH in both cell systems in a dose- and time- dependent manner, which correlated with survival outcome. This study illustrated that arsenic acts as a radiosensitizer and p28 augmented the potential of arsenic in inducing apoptosis, G2/M arrest, and radiosensitization. Further studies are underway to examine the bio-chemical pathways involved in arsenic-mediated cell death and the role of p28 therein

  6. Refined counting of necklaces in one-loop N=4 SYM

    Science.gov (United States)

    Suzuki, Ryo

    2017-06-01

    We compute the grand partition function of N=4 SYM at one-loop in the SU(2) sector with general chemical potentials, extending the results of Pólya's theorem. We make use of finite group theory, applicable to all orders of perturbative 1 /N c expansion. We show that only the planar terms contribute to the grand partition function, which is therefore equal to the grand partition function of an ensemble of {XXX}_{1/2} spin chains. We discuss how Hagedorn temperature changes on the complex plane of chemical potentials.

  7. ERKÜ valimiste tulemused

    Index Scriptorium Estoniae

    2006-01-01

    8. aprilli koosolekul kinnitas valimiste peakomitee XIX Esinduskogu liikmed: Mati Kõiva, Ylo Anson, Juhan Simonson, Airi Vaga, Gilda M. Karu, Taavo Virkhaus, Marju Rink-Abel, Markus Vaga, Eric Suuberg, Endel Reinpõld, Jaak Juhansoo, Ülle Ederma, Lya Karm, Heino Jõgis, Kersti Linask, Jaak Rakfeldt, Erik Puskar, Jüri Linask, Viiu Vanderer, Andres Kurrik, Mati Valdek Laan, Ilmar Vanderer, Henno Uus, Jüri Tults, Urmas Wompa, Astrid Jaanson, Jüri Virkus, Lilian G. G. Bein, Tiina Harris, Tõnu Vanderer

  8. Chatbot-teknologia : sähköinen kaupankäynti ja asiakaspalvelu

    OpenAIRE

    Haavisto, Eero

    2015-01-01

    Tutkimusorganisaatio Gartnerin tutkimuksissa on arvioitu, että vuonna 2020 yli 85 % asiakaspalvelutapahtumista hoituu ilman ihmisen avustusta, jolloin esimerkiksi Yhdysvaltojen 18 miljoonasta myyjästä on jäljellä enää vain noin 4 miljoonaa. Väitettä tukee myös virtuaalisten assistenttien tekemä myynti, mikä on kasvanut 2010-luvulla vuosittain 50 %. Tässä tutkielmassa käsitellään tekoälyä hyödyntävää virtuaalista assistenttia, eli chatbottia. Tutkielman tavoitteena on...

  9. Clasp/SJ Observation of Time Variations of Lyman-Alpha Emissions in a Solar Active Region

    Science.gov (United States)

    Ishikawa, S.; Kubo, M.; Katsukawa, Y.; Kano, R.; Narukage, N.; Ishikawa, R.; Bando, T.; Winebarger, A.; Kobayashi, K.; Trujillo Bueno, J.; hide

    2016-01-01

    The Chromospheric Lyman-alpha SpectroPolarimeter (CLASP) is a sounding rocket experiment launched on September 3, 2015 to investigate the solar chromosphere, and the slit-jaw (SJ) optical system took Lya images with the high time cadence of 0.6 s. By the CLASP/SJ observation, many time variations in the solar chromosphere with the time scale of region and investigated the short (regions. As the result, we found the regions. On the other hand, the <30 s time variations had no dependency on the temperature of the loop.

  10. Dynamic colour and utilizable white fluorescence from Eu/Tb ions codoped lithium-yttrium-aluminium-silicate glasses

    International Nuclear Information System (INIS)

    Shen Lifan; Liu Xiao; Chen Baojie; Lin Hai; Pun, Edwin Yue Bun

    2012-01-01

    A group of dynamic-colour white fluorescences with various colour temperatures that can be applied to circadian lighting are achieved in Eu/Tb-codoped lithium-yttrium-aluminium-silicate (LYAS) glasses, which can be attributed to the simultaneous generation of three primary colours emitting from Eu 3+ (red), Eu 2+ (blue) and Tb 3+ (green) by varying the ultraviolet (UV) radiation wavelength. Fluorescence colour coordinates pass through the whole white region of the CIE x, y chromaticity diagram when the UV excitation wavelength is increased from 300 to 370 nm. A favourable white light with colour coordinates (0.338, 0.298) close to the equal energy white is obtained under 360 nm excitation. These results indicate that the Eu/Tb-codoped LYAS glasses are a promising candidate to develop white lighting devices under the excitation of commercial UV light-emitting diodes, and a smart lighting system based on rare-earth doped glasses will be a potential illumination source offering controllability of the colour temperature that can adjust to specific environments and requirements, and benefit human health, well-being and productivity. (paper)

  11. Number distribution of emitted electrons by MeV H+ impact on carbon

    Science.gov (United States)

    Ogawa, H.; Koyanagi, Y.; Hongo, N.; Ishii, K.; Kaneko, T.

    2017-09-01

    The statistical distributions of the number of the forward- and backward-emitted secondary electrons (SE's) from a thin carbon foil have been measured in coincidence with foil-transmitted H+ ions of 0.5-3.0 MeV in every 0.5 MeV step. The measured SE energy spectra were fitted by assuming a Pólya distribution for the simultaneous n-SE emission probabilities. For our previous data with a couple of the carbon foils with different thicknesses, a similar analysis has been carried out. As a result, it was found that the measured spectra could be reproduced as well as by an analysis without placing any restriction on the emission probabilities both for the forward and backward SE emission. The obtained b-parameter of the Pólya distribution, which is a measure of the deviation from a Poisson distribution due to the cascade multiplication by high energy internal SE's, increases monotonically with the incident energy of proton beams. On the other hand, a clear foil-thickness dependence is not observed for the b-parameter. A theoretical model which could reproduced the magnitude of the b-parameter for the SE energy spectra obtained with thick Au, Cu and Al targets is found to overestimates our values for thin carbon foils significantly. Another model calculation is found to reproduce our b-values very well.

  12. Effect of Various Catalysts on the Stability of Characteristics of Acetone Sensors Based on Thin Nanocrystalline SnO2 Films

    Science.gov (United States)

    Sevastyanov, E. Yu.; Maksimova, N. K.; Potekaev, A. I.; Khludkova, L. S.; Chernikov, E. V.; Davydova, T. A.

    2018-02-01

    The results of studies of electrical and gas sensitive characteristics of acetone sensors based on thin nanocrystalline SnO2 films with various catalysts deposited on the surface (Pt/Pd, Au) and introduced into the volume (Au, Ni, Co) are presented. Films containing impurities of gold and 3d-metals were obtained by the method of magnetron sputtering of mosaic targets. Particular attention was paid to the influence of the longterm tests and humidity level on the properties of sensors. It is shown that the sensors with the deposited dispersed gold layers with Au+Ni and, especially, Au+Co additives introduced into the volume are characterized by the increased stability in the process of testing under prolonged exposure to acetone and also under conditions of varying humidity.

  13. Engineering and Scaling the Spontaneous Magnetization Reversal of Faraday Induced Magnetic Relaxation in Nano-Sized Amorphous Ni Coated on Crystalline Au.

    Science.gov (United States)

    Li, Wen-Hsien; Lee, Chi-Hung; Kuo, Chen-Chen

    2016-05-28

    We report on the generation of large inverse remanent magnetizations in nano-sized core/shell structure of Au/Ni by turning off the applied magnetic field. The remanent magnetization is very sensitive to the field reduction rate as well as to the thermal and field processes before the switching off of the magnetic field. Spontaneous reversal in direction and increase in magnitude of the remanent magnetization in subsequent relaxations over time were found. All of the various types of temporal relaxation curves of the remanent magnetizations are successfully scaled by a stretched exponential decay profile, characterized by two pairs of relaxation times and dynamic exponents. The relaxation time is used to describe the reduction rate, while the dynamic exponent describes the dynamical slowing down of the relaxation through time evolution. The key to these effects is to have the induced eddy current running beneath the amorphous Ni shells through Faraday induction.

  14. Engineering and Scaling the Spontaneous Magnetization Reversal of Faraday Induced Magnetic Relaxation in Nano-Sized Amorphous Ni Coated on Crystalline Au

    Science.gov (United States)

    Li, Wen-Hsien; Lee, Chi-Hung; Kuo, Chen-Chen

    2016-01-01

    We report on the generation of large inverse remanent magnetizations in nano-sized core/shell structure of Au/Ni by turning off the applied magnetic field. The remanent magnetization is very sensitive to the field reduction rate as well as to the thermal and field processes before the switching off of the magnetic field. Spontaneous reversal in direction and increase in magnitude of the remanent magnetization in subsequent relaxations over time were found. All of the various types of temporal relaxation curves of the remanent magnetizations are successfully scaled by a stretched exponential decay profile, characterized by two pairs of relaxation times and dynamic exponents. The relaxation time is used to describe the reduction rate, while the dynamic exponent describes the dynamical slowing down of the relaxation through time evolution. The key to these effects is to have the induced eddy current running beneath the amorphous Ni shells through Faraday induction. PMID:28773549

  15. Resistance to sulfur poisoning of Ni-based alloy with coinage (IB) metals

    International Nuclear Information System (INIS)

    Xu, Xiaopei; Zhang, Yanxing; Yang, Zongxian

    2015-01-01

    Highlights: • The effects of IB metal dopants on the S poisoning features of Ni are analyzed. • IB metal dopants can modify the surface electronic structure of Ni. • IB metal dopants can increase the S tolerance of Ni at an optimized concentration. • Au is a preferred dopant to increase the resistance to sulfur poisoning of Ni. - Abstract: The poisoning effects of S atom on the (1 0 0), (1 1 0) and (1 1 1) metal surfaces of pure Ni and Ni-based alloy with IB (coinage) metals (Cu, Ag, Au) are systematically studied. The effects of IB metal dopants on the S poisoning features are analyzed combining the density functional theory (DFT) results with thermodynamics data using the ab initio atomistic thermodynamic method. It is found that introducing IB doping metals into Ni surface can shift the d-band center downward from the Fermi level and weaken the adsorption of S on the (1 0 0) and (1 1 0) surfaces, and the S tolerance ability increases in the order of Ni, Cu/Ni, Ag/Ni and Au/Ni. Nevertheless, on the (1 1 1) surface, the S tolerance ability increases in the order of Ag/Ni (or Cu/Ni), Ni, and Au/Ni. When we increase the coverage of the IB metal dopants, we found that not only Au, but Cu and Ag can increase its S tolerance. We therefore propose that alloying can increase its S tolerance and alloying with Au would be a better way to increase the resistance to sulfur poisoning of the Ni anode as compared with the pure Ni and the Ag- or, Cu-doped Ni materials.

  16. Battery Charge Affects the Stability of Light Intensity from Light-emitting Diode Light-curing Units.

    Science.gov (United States)

    Tongtaksin, A; Leevailoj, C

    This study investigated the influence of battery charge levels on the stability of light-emitting diode (LED) curing-light intensity by measuring the intensity from fully charged through fully discharged batteries. The microhardness of resin composites polymerized by the light-curing units at various battery charge levels was measured. The light intensities of seven fully charged battery LED light-curing units-1) LY-A180, 2) Bluephase, 3) Woodpecker, 4) Demi Plus, 5) Saab II, 6) Elipar S10, and 7) MiniLED-were measured with a radiometer (Kerr) after every 10 uses (20 seconds per use) until the battery was discharged. Ten 2-mm-thick cylindrical specimens of A3 shade nanofilled resin composite (PREMISE, Kerr) were prepared per LED light-curing unit group. Each specimen was irradiated by the fully charged light-curing unit for 20 seconds. The LED light-curing units were then used until the battery charge fell to 50%. Specimens were prepared again as described above. This was repeated again when the light-curing units' battery charge fell to 25% and when the light intensity had decreased to 400 mW/cm 2 . The top/bottom surface Knoop hardness ratios of the specimens were determined. The microhardness data were analyzed by one-way analysis of variance with Tukey test at a significance level of 0.05. The Pearson correlation coefficient was used to determine significant correlations between surface hardness and light intensity. We found that the light intensities of the Bluephase, Demi Plus, and Elipar S10 units were stable. The intensity of the MiniLED unit decreased slightly; however, it remained above 400 mW/cm 2 . In contrast, the intensities of the LY-A180, Woodpecker, and Saab II units decreased below 400 mW/cm 2 . There was also a significant decrease in the surface microhardnesses of the resin composite specimens treated with MiniLED, LY-A180, Woodpecker, and Saab II. In conclusion, the light intensity of several LED light-curing units decreased as the battery was

  17. Conference on Inequalities and Applications

    CERN Document Server

    Losonczi, László; Gilányi, Attila; Páles, Zsolt; Plum, Michael

    2009-01-01

    Inequalities continue to play an essential role in mathematics. Perhaps, they form the last field comprehended and used by mathematicians in all areas of the discipline. Since the seminal work Inequalities (1934) by Hardy, Littlewood and Pólya, mathematicians have laboured to extend and sharpen their classical inequalities. New inequalities are discovered every year, some for their intrinsic interest whilst others flow from results obtained in various branches of mathematics. The study of inequalities reflects the many and various aspects of mathematics. On one hand, there is the systematic search for the basic principles and the study of inequalities for their own sake. On the other hand, the subject is the source of ingenious ideas and methods that give rise to seemingly elementary but nevertheless serious and challenging problems. There are numerous applications in a wide variety of fields, from mathematical physics to biology and economics. This volume contains the contributions of the participants of th...

  18. The non-Euclidean revolution

    CERN Document Server

    Trudeau, Richard J

    1986-01-01

    How unique and definitive is Euclidean geometry in describing the "real" space in which we live? Richard Trudeau confronts the fundamental question of truth and its representation through mathematical models in The Non-Euclidean Revolution. First, the author analyzes geometry in its historical and philosophical setting; second, he examines a revolution every bit as significant as the Copernican revolution in astronomy and the Darwinian revolution in biology; third, on the most speculative level, he questions the possibility of absolute knowledge of the world. Trudeau writes in a lively, entertaining, and highly accessible style. His book provides one of the most stimulating and personal presentations of a struggle with the nature of truth in mathematics and the physical world. A portion of the book won the Pólya Prize, a distinguished award from the Mathematical Association of America. "Trudeau meets the challenge of reaching a broad audience in clever ways...(The book) is a good addition to our literature o...

  19. The Golden-Thompson inequality: Historical aspects and random matrix applications

    International Nuclear Information System (INIS)

    Forrester, Peter J.; Thompson, Colin J.

    2014-01-01

    The Golden-Thompson inequality, Tr (e A+B ) ⩽ Tr (e A e B ) for A, B Hermitian matrices, appeared in independent works by Golden and Thompson published in 1965. Both of these were motivated by considerations in statistical mechanics. In recent years the Golden-Thompson inequality has found applications to random matrix theory. In this article, we detail some historical aspects relating to Thompson's work, giving in particular a hitherto unpublished proof due to Dyson, and correspondence with Pólya. We show too how the 2 × 2 case relates to hyperbolic geometry, and how the original inequality holds true with the trace operation replaced by any unitarily invariant norm. In relation to the random matrix applications, we review its use in the derivation of concentration type lemmas for sums of random matrices due to Ahlswede-Winter, and Oliveira, generalizing various classical results

  20. The non-Euclidean revolution with an introduction by H.S.M. Coxeter

    CERN Document Server

    Trudeau, Richard J

    2001-01-01

    How unique and definitive is Euclidean geometry in describing the "real" space in which we live? Richard Trudeau confronts the fundamental question of truth and its representation through mathematical models in The Non-Euclidean Revolution. First, the author analyzes geometry in its historical and philosophical setting; second, he examines a revolution every bit as significant as the Copernican revolution in astronomy and the Darwinian revolution in biology; third, on the most speculative level, he questions the possibility of absolute knowledge of the world. Trudeau writes in a lively, entertaining, and highly accessible style. His book provides one of the most stimulating and personal presentations of a struggle with the nature of truth in mathematics and the physical world. A portion of the book won the Pólya Prize, a distinguished award from the Mathematical Association of America.

  1. Editorial: The FQS-Issue "Doing Biographical Research". Four Years of Publishing FQS as an Example for Social Science Open Access Journals

    Directory of Open Access Journals (Sweden)

    Katja Mruck

    2003-09-01

    Full Text Available In FQS 4(3—"Doing Biographical Research"—social scientists discuss from different disciplinary and national stances the interview with Hülya, a Turkish migrant living and working in Germany. In addition to contributions linked directly to the issue topic, eight single contributions, nine review essays and review notes and two conference reports are published, coming from researchers from eight nations and seven academic disciplines. Approximately 450 articles have been published since the first FQS issue was accessible on-line in January 2000. In addition to the contributions to the new issue "Doing Biographical Research," the current state of FQS is briefly reviewed. FQS is also discussed as an example for social science open access journals, being part of the open access initiatives which aim to make scientific information accessible worldwide free of cost. URN: urn:nbn:de:0114-fqs0303176

  2. Non-Selective Evolution of Growing Populations.

    Directory of Open Access Journals (Sweden)

    Karl Wienand

    Full Text Available Non-selective effects, like genetic drift, are an important factor in modern conceptions of evolution, and have been extensively studied for constant population sizes (Kimura, 1955; Otto and Whitlock, 1997. Here, we consider non-selective evolution in the case of growing populations that are of small size and have varying trait compositions (e.g. after a population bottleneck. We find that, in these conditions, populations never fixate to a trait, but tend to a random limit composition, and that the distribution of compositions "freezes" to a steady state. This final state is crucially influenced by the initial conditions. We obtain these findings from a combined theoretical and experimental approach, using multiple mixed subpopulations of two Pseudomonas putida strains in non-selective growth conditions (Matthijs et al, 2009 as model system. The experimental results for the population dynamics match the theoretical predictions based on the Pólya urn model (Eggenberger and Pólya, 1923 for all analyzed parameter regimes. In summary, we show that exponential growth stops genetic drift. This result contrasts with previous theoretical analyses of non-selective evolution (e.g. genetic drift, which investigated how traits spread and eventually take over populations (fixate (Kimura, 1955; Otto and Whitlock, 1997. Moreover, our work highlights how deeply growth influences non-selective evolution, and how it plays a key role in maintaining genetic variability. Consequently, it is of particular importance in life-cycles models (Melbinger et al, 2010; Cremer et al, 2011; Cremer et al, 2012 of periodically shrinking and expanding populations.

  3. Observed Responses of Mesospheric Water Vapor to Solar Cycle and Dynamical Forcings

    Science.gov (United States)

    Remsberg, Ellis; Damadeo, Robert; Natarajan, Murali; Bhatt, Praful

    2018-04-01

    This study focuses on responses of mesospheric water vapor (H2O) to the solar cycle flux at Lyman-α wavelength and to dynamical forcings according to the multivariate El-Nino/Southern Oscillation (ENSO) index. The zonal-averaged responses are for latitudes from 60°S to 60°N and pressure-altitudes from 0.01 to 1.0 hPa, as obtained from multiple linear regression analyses of time series of H2O from the Halogen Occultation Experiment for July 1992 to November 2005. The results compare very well with those from a separate simultaneous temporal and spatial (STS) method that also confirms that there are no significant sampling biases affecting both sets of results. Distributions of the seasonal amplitudes for temperature and H2O are in accord with the seasonal net circulation. In general, the responses of H2O to ENSO are anticorrelated with those of temperature. H2O responses to multivariate ENSO index are negative in the upper mesosphere and largest in the Northern Hemisphere; responses in the lower mesosphere are more symmetric with latitude. H2O responses to the Lyman-α flux (Lya) vary from strong negative values in the uppermost mesosphere to very weak, positive values in the tropical lowermost mesosphere. However, the effects of those H2O responses to the solar activity extend to the rest of the mesosphere via dynamical processes. Profiles of the responses to ENSO and Lya also agree reasonably with published results for H2O at the low latitudes from the Microwave Limb Sounder.

  4. 4U 1626-67 as Seen by Suzaku Before and After the 2008 Torque Reversal

    Science.gov (United States)

    Camero-Arranz, A.; Pottschmidt, K.; Finger, M. H.; Ikhsanov, N. R.; Wilson-Hodge, C. A.; Marcu, D. M.

    2012-01-01

    Aims. The accretion-powered pulsar 4U 1626-67 experienced a new torque reversal at the beginning of 2008, after about 18 years of steadily spinning down. The main goal of the present work is to study this recent torque reversal that occurred in 2008 February. Methods. We present a spectral analysis of this source using two pointed observations performed by Suzaku in 2006 March and in 2010 September. Results. We confirm with Suzaku the presence of a strong emission-line complex centered on 1 keV, with the strongest line being the hydrogen-like Ne Lya at 1.025(3) keV. We were able to resolve this complex with up to seven emission lines. A dramatic increase of the intensity of the Ne Lya line after the 2008 torque reversal occurred, with the equivalent width of this line reaching almost the same value measured by ASCA in 1993. We also report on the detection of a cyclotron line feature centered at approximately 37 keV. In spite of the fact that an increase of the X-ray luminosity (0.5-100keV) of a factor of approximately 2.8 occurred between these two observations, no significant change in the energy of the cyclotron line feature was observed. However, the intensity of the approximately 1 keV line complex increased by an overall factor of approximately 8. Conclusions. Our results favor a scenario in which the neutron star in 4U 1626-67 accretes material from a geometrically thin disk during both the spin-up and spin-down phases.

  5. On the use of symmetry in configurational analysis for the simulation of disordered solids.

    Science.gov (United States)

    Mustapha, Sami; D'Arco, Philippe; De La Pierre, Marco; Noël, Yves; Ferrabone, Matteo; Dovesi, Roberto

    2013-03-13

    The starting point for a quantum mechanical investigation of disordered systems usually implies calculations on a limited subset of configurations, generated by defining either the composition of interest or a set of compositions ranging from one end member to another, within an appropriate supercell of the primitive cell of the pure compound. The way in which symmetry can be used in the identification of symmetry independent configurations (SICs) is discussed here. First, Pólya's enumeration theory is adopted to determine the number of SICs, in the case of both varying and fixed composition, for colors numbering two or higher. Then, De Bruijn's generalization is presented, which allows analysis of the case where the colors are symmetry related, e.g. spin up and down in magnetic systems. In spite of their efficiency in counting SICs, neither Pólya's nor De Bruijn's theory helps in solving the difficult problem of identifying the complete list of SICs. Representative SICs are obtained by adopting an orderly generation approach, based on lexicographic ordering, which offers the advantage of avoiding the (computationally expensive) analysis and storage of all the possible configurations. When the number of colors increases, this strategy can be combined with the surjective resolution principle, which permits the efficient generation of SICs of a problem in |R| colors starting from the ones obtained for the (|R| - 1)-colors case. The whole scheme is documented by means of three examples: the abstract case of a square with C(4v) symmetry and the real cases of the garnet and olivine mineral families.

  6. El debate sobre las heurísticas. Una disputa sobre los criterios de buen razonamiento entre la Tradición de Heurística y Sesgo y la Racionalidad Ecológica

    Directory of Open Access Journals (Sweden)

    Ana Laura Fonseca

    2016-01-01

    Full Text Available El objetivo del artículo es mostrar que el problema central detrás del debate sostenido entre Daniel Kahneman y Gerd Gigerenzer acerca del papel del razonamiento heurístico en nuestra comprensión de la racionalidad humana es cómo caracterizar el razonamiento normativo. Para ello, muestro que en la literatura sobre razonamiento heurístico se ha asumido una distinción tajante –incluso en muchos casos se asume una oposición– entre razonamiento formal y razonamiento heurístico. Argumento que la discusión se ha centrado en cuál de estos tipos de razonamientos debe ser considerado como modelo de nuestro razonar; hago ver que analizando textos de George Pólya y de Herbert A. Simon podemos rastrear este problema. Este análisis nos permitirá hacer notar la relevancia de dicho debate, que muchas veces ha sido una mera disputa semántica. In this paper I argue that the central problem behind the debate between Daniel Kahneman and Gerd Gigerenzer regarding the role of heuristic reasoning in our comprehension of human rationality is the way in which we characterize normative reasoning. To this end, I show how, in the recent literature about heuristic reasoning, a sharp distinction has been drawn –in certain cases, even an opposition– between formal and heuristic reasoning. I argue that the discussion has focused on which one of these kinds of reasoning should be taken as the right model of our reasoning. I show that this point may be tracked by analyzing the texts of George Pólya and Herbert A. Simon. This analysis will allow us to notice the relevance of said debate, which has, often times, been considered a mere semantic dispute.

  7. Trends and Issues in Distance Education: International Perspectives

    Directory of Open Access Journals (Sweden)

    Erhan EROGLU

    2006-04-01

    Full Text Available Trends and Issues in Distance Education: International Perspectives Edited by Yusra Laila Visser, Lya Visser, Michael Simonsın, & Ray Amirault, 2005, United States of America: Information Age Publishing, Inc. pp. 315. ISBN 1-59311-212-2 Reviewed by Dr. Erhan EROGLU Anadolu University Eskisehir, TURKEY In this book, the terms of “distance education” has been discussed from different perspectives. The term “distance education” conjures up in many minds the image of modern, computer-enabled technology that has blossomed in only the last twenty years. Many of the lessons learned over the last century of distance education research and practice have been implemented in a wide variety of distance education programs worldwide, from higher education online learning programs in the United States to rural, radio-based instructional programs in developing countries. Distance education is truly international discipline. While it is true that the term “distance education” has a universal definiton, local distance ducation experiences are often quite idiosyncratic. This idiosyncratic nature emerges from the need to integrate distance education within the constraints, oppurtunities, and realities of spesific cultural and geographic contexts. From these local distance education experiences, educators are developing new understandings of the broader field of distance education, including the trends and issues present in the field. ORGANIZATION OF THE SECTIONS This book has been organized by thematic content into four main sections. Each of these sections represents a unique level of analysis for trends and issues in distance education. Part I presents five distinct perspectives on the state of distance education and the trends and issues of the field. First perspective of five distinct perpectives is “a survey of progressive and conservative trends in education with implications for distance education practice.” Second perspective is

  8. Resolution of the diffusional paradox predicting infinitely fast kinetics on the nanoscale

    Science.gov (United States)

    Beke, D. L.; Erdélyi, Z.

    2006-01-01

    In our paper, we offer a natural resolution for a long-standing paradox in diffusion. We show that the growth rate of the diffusion zone (reaction layer) should not go to infinity with decreasing time (as 1/t ), just because the diffusion permeability of the interface is finite. Expression for the changeover thickness X* between the linear and parabolic regimes of the interface shift in phase separating binary A(B) systems is derived in the framework of a deterministic atomistic model for diffusion. X* lies typically between 0.01 and 300nm , depending on the composition dependence of the diffusion coefficient and the phase separation tendency of the alloy. While in ideal binary alloys with composition independent diffusivity, the deviation from the parabolic law practically cannot be observed, in real systems (where the diffusion coefficient can change several orders of magnitude with the composition), measurable deviations are expected as it was experimentally observed very recently in the Ni/Cu and Au/Ni systems. We also offer an atomistic explanation for the phenomenological interface transfer coefficient K . It measures the finite interface permeability (proportional to the jump frequency across the interface) and thus it controls the shift of the interface at short times (diffusion distances). Although it is almost exclusively accepted in the literature that linear growth kinetics are the result of interface reaction control, our results suggest that the linear or nonparabolic growth of a reaction layer on the nanoscale cannot be automatically interpreted by an interface reaction.

  9. Vertically p-n-junctioned GaN nano-wire array diode fabricated on Si(111) using MOCVD.

    Science.gov (United States)

    Park, Ji-Hyeon; Kim, Min-Hee; Kissinger, Suthan; Lee, Cheul-Ro

    2013-04-07

    We demonstrate the fabrication of n-GaN:Si/p-GaN:Mg nanowire arrays on (111) silicon substrate by metal organic chemical vapor deposition (MOCVD) method .The nanowires were grown by a newly developed two-step growth process. The diameter of as-grown nanowires ranges from 300-400 nm with a density of 6-7 × 10(7) cm(-2). The p- and n-type doping of the nanowires is achieved with Mg and Si dopant species. Structural characterization by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) indicates that the nanowires are relatively defect-free. The room-temperature photoluminescence emission with a strong peak at 370 nm indicates that the n-GaN:Si/p-GaN:Mg nanowire arrays have potential application in light-emitting nanodevices. The cathodoluminscence (CL) spectrum clearly shows a distinct optical transition of GaN nanodiodes. The nano-n-GaN:Si/p-GaN:Mg diodes were further completed using a sputter coating approach to deposit Au/Ni metal contacts. The polysilazane filler has been etched by a wet chemical etching process. The n-GaN:Si/p-GaN:Mg nanowire diode was fabricated for different Mg source flow rates. The current-voltage (I-V) measurements reveal excellent rectifying properties with an obvious turn-on voltage at 1.6 V for a Mg flow rate of 5 sccm (standard cubic centimeters per minute).

  10. Monolayer-by-monolayer growth of platinum films on complex carbon fiber paper structure

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Liuqing; Zhang, Yunxia [Key Laboratory of Applied Surface and Colloid Chemistry, National Ministry of Education, Shaanxi Key Laboratory for Advanced Energy Devices, Shaanxi Engineering Lab for Advanced Energy Technology, School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710119 (China); Liu, Shengzhong, E-mail: szliu@dicp.ac.cn [Key Laboratory of Applied Surface and Colloid Chemistry, National Ministry of Education, Shaanxi Key Laboratory for Advanced Energy Devices, Shaanxi Engineering Lab for Advanced Energy Technology, School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710119 (China); Dalian National Laboratory for Clean Energy, iChEM, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China)

    2017-06-15

    Graphical abstract: A controlled monolayer-by-monolayer deposition process has been developed to fabricate Pt coating on carbon fiber paper with complex network structures using a dual buffer strategy. This development may pave a way to fabricate superior Pt catalysts with the minimal Pt usage. In fact, the present Pt group metal loading is 25 times lower than the U.S. DOE 2017 target value. - Highlights: • Developed a controlled monolayer-by-monolayer Pt deposition using a dual buffer strategy. • The present Pt group metal loading is 25 times lower than the U.S. DOE 2017 target value. • This development may pave a way to fabricate superior Pt catalysts with the minimal Pt usage. - Abstract: A controlled monolayer-by-monolayer deposition process has been developed to fabricate Pt coating on carbon fiber paper with complex network structures using a dual buffer (Au/Ni) strategy. The X-ray diffraction, electrochemical quartz crystal microbalance, current density analyses, and X-ray photoelectron spectroscopy results conclude that the monolayer deposition process accomplishes full coverage on the substrate and that the thickness of the deposition layer can be controlled on a single atom scale. This development may pave a way to fabricate superior Pt catalysts with the minimal Pt usage. In fact, the present Pt group metal loading is 25 times lower than the U.S. DOE 2017 target value.

  11. Synthesis of p-type GaN nanowires.

    Science.gov (United States)

    Kim, Sung Wook; Park, Youn Ho; Kim, Ilsoo; Park, Tae-Eon; Kwon, Byoung Wook; Choi, Won Kook; Choi, Heon-Jin

    2013-09-21

    GaN has been utilized in optoelectronics for two decades. However, p-type doping still remains crucial for realization of high performance GaN optoelectronics. Though Mg has been used as a p-dopant, its efficiency is low due to the formation of Mg-H complexes and/or structural defects in the course of doping. As a potential alternative p-type dopant, Cu has been recognized as an acceptor impurity for GaN. Herein, we report the fabrication of Cu-doped GaN nanowires (Cu:GaN NWs) and their p-type characteristics. The NWs were grown vertically via a vapor-liquid-solid (VLS) mechanism using a Au/Ni catalyst. Electrical characterization using a nanowire-field effect transistor (NW-FET) showed that the NWs exhibited n-type characteristics. However, with further annealing, the NWs showed p-type characteristics. A homo-junction structure (consisting of annealed Cu:GaN NW/n-type GaN thin film) exhibited p-n junction characteristics. A hybrid organic light emitting diode (OLED) employing the annealed Cu:GaN NWs as a hole injection layer (HIL) also demonstrated current injected luminescence. These results suggest that Cu can be used as a p-type dopant for GaN NWs.

  12. Plasmon-induced photoelectrochemical biosensor for in situ real-time measurement of biotin-streptavidin binding kinetics under visible light irradiation

    International Nuclear Information System (INIS)

    Guo, Jingchun; Oshikiri, Tomoya; Ueno, Kosei; Shi, Xu; Misawa, Hiroaki

    2017-01-01

    We developed a localized surface plasmon-induced visible light-responsive photoelectrochemical (PEC) biosensor using a titanium dioxide (TiO_2) photoelectrode loaded with gold nanoislands (AuNIs) for in situ real-time measurement of biotin-streptavidin association. As a proof of concept, self-assembled thiol-terminated biotin molecules bound on a AuNIs/TiO_2 photoelectrode were successfully utilized to explore the photocurrent response to streptavidin-modified gold nanoparticle (STA-AuNP) solutions. This plasmon-induced PEC biosensor is simple and easy to miniaturize. Additionally, the PEC biosensor achieves highly sensitive measurements under only visible light irradiation and prevents the UV-induced damage of samples. Furthermore, a novel approach has been proposed to realize the real-time monitoring of biotin-STA binding affinities and kinetics by analyzing the PEC sensing characteristics. This PEC biosensor and novel analysis method could provide a new approach for the specific electrical detection and real-time kinetic measurements for clinical diagnostics and drug development. - Highlights: • A plasmon-induced visible light-responsive photoelectrochemical biosensor is developed and the system can be miniaturized.

  13. Properties of Resistive Hydrogen Sensors as a Function of Additives of 3 D-Metals Introduced in the Volume of Thin Nanocrystalline SnO2 Films

    Science.gov (United States)

    Sevast'yanov, E. Yu.; Maksimova, N. K.; Potekaev, A. I.; Sergeichenko, N. V.; Chernikov, E. V.; Almaev, A. V.; Kushnarev, B. O.

    2017-11-01

    Analysis of the results of studying electrical and gas sensitive characteristics of the molecular hydrogen sensors based on thin nanocrystalline SnO2 films coated with dispersed Au layers and containing Au+Ni and Au+Co impurities in the bulk showed that the characteristics of these sensors are more stable under the prolonged exposure to hydrogen in comparison with Au/SnO2:Sb, Au films modified only with gold. It has been found that introduction of the nickel and cobalt additives increases the band bending at the grain boundaries of tin dioxide already in freshly prepared samples, which indicates an increase in the density Ni of the chemisorbed oxygen. It is important that during testing, the band bending eφs at the grain boundaries of tin dioxide additionally slightly increases. It can be assumed that during crystallization of films under thermal annealing, the 3d-metal atoms in the SnO2 volume partially segregate on the surface of microcrystals and form bonds with lattice oxygen, the superstoichiometric tin atoms are formed, and the density Ni increases. If the bonds of oxygen with nickel and cobalt are stronger than those with tin, then, under the prolonged tests, atomic hydrogen will be oxidized not by lattice oxygen, but mainly by the chemisorbed one. In this case, stability of the sensors' characteristics increases.

  14. The graphene/Au/Ni interface and its application in the construction of a graphene spin filter

    International Nuclear Information System (INIS)

    Rybkina, A A; Rybkin, A G; Adamchuk, V K; Marchenko, D; Shikin, A M; Varykhalov, A; Sánchez -Barriga, J

    2013-01-01

    A modification of the contact of graphene with ferromagnetic electrodes in a model of the graphene spin filter allowing restoration of the graphene electronic structure is proposed. It is suggested for this aim to intercalate into the interface between the graphene and the ferromagnetic (Ni or Co) electrode a Au monolayer to block the strong interaction between the graphene and Ni (Co) and, thus, prevent destruction of the graphene electronic structure which evolves in direct contact of graphene with Ni (Co). It is also suggested to insert an additional buffer graphene monolayer with the size limited by that of the electrode between the main graphene sheet providing spin current transport and the Au/Ni electrode injecting the spin current. This will prevent the spin transport properties of graphene from influencing contact phenomena and eliminate pinning of the graphene electronic structure relative to the Fermi level of the metal, thus ensuring efficient outflow of injected electrons into the graphene. The role of the spin structure of the graphene/Au/Ni interface with enhanced spin–orbit splitting of graphene π states is also discussed, and its use is proposed for additional spin selection in the process of the electron excitation. (paper)

  15. How fast are the ultra-fast nano-scale solid-liquid phase transitions induced by energetic particles in solids?

    International Nuclear Information System (INIS)

    Lopasso, E.M.; Caro, A.; Caro, M.

    2003-01-01

    We study the thermodynamic forces acting on the evolution of the nanoscale regions excited by collisions of energetic particles into solid targets. We analyze the role of diffusion, thermo-migration, and the liquidus-solidus two-phase field crossing, as the system cools down from the collision-induced melt under different conditions of energy deposition. To determine the relevance of these thermodynamic forces, solute redistribution is evaluated using molecular dynamics simulations of equilibrium Au-Ni solid solutions. At low collision energies, our results show that the quenching of spherical cascades is too fast to allow for solute redistribution according to equilibrium solidification as determined from the equilibrium phase diagram (zone refining effect), and only thermo-migration is observed. At higher energies instead, in the cylindrical symmetry of ion tracks, quenching rate is in a range that shows the combined effects of thermo-migration and solute redistribution that, depending on the material, can reinforce or cancel each other. These results are relevant for the interpretation of the early stage of radiation damage in alloys, and show that the combination of ultra-fast but nano-scale characteristics of these processes can still be described in terms of linear response of the perturbed system

  16. Plasmon-induced photoelectrochemical biosensor for in situ real-time measurement of biotin-streptavidin binding kinetics under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jingchun; Oshikiri, Tomoya; Ueno, Kosei; Shi, Xu [Research Institute for Electronic Science, Hokkaido University, Sapporo 001-0021 (Japan); Misawa, Hiroaki, E-mail: misawa@es.hokudai.ac.jp [Research Institute for Electronic Science, Hokkaido University, Sapporo 001-0021 (Japan); Department of Applied Chemistry & Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan (China)

    2017-03-08

    We developed a localized surface plasmon-induced visible light-responsive photoelectrochemical (PEC) biosensor using a titanium dioxide (TiO{sub 2}) photoelectrode loaded with gold nanoislands (AuNIs) for in situ real-time measurement of biotin-streptavidin association. As a proof of concept, self-assembled thiol-terminated biotin molecules bound on a AuNIs/TiO{sub 2} photoelectrode were successfully utilized to explore the photocurrent response to streptavidin-modified gold nanoparticle (STA-AuNP) solutions. This plasmon-induced PEC biosensor is simple and easy to miniaturize. Additionally, the PEC biosensor achieves highly sensitive measurements under only visible light irradiation and prevents the UV-induced damage of samples. Furthermore, a novel approach has been proposed to realize the real-time monitoring of biotin-STA binding affinities and kinetics by analyzing the PEC sensing characteristics. This PEC biosensor and novel analysis method could provide a new approach for the specific electrical detection and real-time kinetic measurements for clinical diagnostics and drug development. - Highlights: • A plasmon-induced visible light-responsive photoelectrochemical biosensor is developed and the system can be miniaturized.

  17. Oxygen reduction of several gold alloys in 1-molar potassium hydroxide

    Science.gov (United States)

    Miller, R. O.

    1975-01-01

    With rotated disk-and-ring equipment, polarograms and other electrochemical measurements were made of oxygen reduction in 1-molar potassium hydroxide on an equiatomic gold-copper (Au-Cu) alloy and a Au-Cu alloy doped with either indium (In) or cobalt (Co) and on Au doped with either nickel (Ni) or platinum (Pt). The results were compared with those for pure Au and pure Pt. The two-electron reaction dominated on all Au alloys as it did on Au. The polarographic results at lower polarization potentials were compared, assuming exclusively a two-step reduction. A qualified ranking of cathodic electrocatalytic activity on the freshly polished reduced disks was indicated: anodized Au Au-Cu-In Au-Cu Au-Cu-Co is equivalent or equal to Au-Pt Au-Ni. Aging in distilled water improved the electrocatalytic efficiency of Au-Cu-Co, Au-Cu, and (to a lesser extent) Au-Cu-In.

  18. Szervezeti karriergondozás a nők előmenetelének szolgálatában: Sikeres európai uniós és hazai megoldások (Organizational career development in the career chance of women: successful European and Hungarian solutions)

    OpenAIRE

    Koncz, Katalin

    2007-01-01

    A szerző tanulmányában a női karrierpálya és a szervezeti karriergondozás sajátosságait mutatja be. A női munkaerő sajátos munkaerő. Sajátosságait a társadalmi munkamegosztásban elfoglalt helye, szerepe, az ebből is táplálkozó férfiakétól eltérő személyisége, motivációja, habitusa, munkahellyel és munkakörrel kapcsolatos elvárásai alkotják. A hatékony emberierőforrás-menedzsment célja, hogy a rendelkezésre álló munkaerő-potenciált, kompetenciatárat minél jobban kihasználja. Ezért ...

  19. Discrete dispersion models and their Tweedie asymptotics

    DEFF Research Database (Denmark)

    Jørgensen, Bent; Kokonendji, Célestin C.

    2016-01-01

    The paper introduce a class of two-parameter discrete dispersion models, obtained by combining convolution with a factorial tilting operation, similar to exponential dispersion models which combine convolution and exponential tilting. The equidispersed Poisson model has a special place in this ap......The paper introduce a class of two-parameter discrete dispersion models, obtained by combining convolution with a factorial tilting operation, similar to exponential dispersion models which combine convolution and exponential tilting. The equidispersed Poisson model has a special place...... in this approach, whereas several overdispersed discrete distributions, such as the Neyman Type A, Pólya-Aeppli, negative binomial and Poisson-inverse Gaussian, turn out to be Poisson-Tweedie factorial dispersion models with power dispersion functions, analogous to ordinary Tweedie exponential dispersion models...... with power variance functions. Using the factorial cumulant generating function as tool, we introduce a dilation operation as a discrete analogue of scaling, generalizing binomial thinning. The Poisson-Tweedie factorial dispersion models are closed under dilation, which in turn leads to a Poisson...

  20. Characteristics of service requests and service processes of fire and rescue service dispatch centers: analysis of real world data and the underlying probability distributions.

    Science.gov (United States)

    Krueger, Ute; Schimmelpfeng, Katja

    2013-03-01

    A sufficient staffing level in fire and rescue dispatch centers is crucial for saving lives. Therefore, it is important to estimate the expected workload properly. For this purpose, we analyzed whether a dispatch center can be considered as a call center. Current call center publications very often model call arrivals as a non-homogeneous Poisson process. This bases on the underlying assumption of the caller's independent decision to call or not to call. In case of an emergency, however, there are often calls from more than one person reporting the same incident and thus, these calls are not independent. Therefore, this paper focuses on the dependency of calls in a fire and rescue dispatch center. We analyzed and evaluated several distributions in this setting. Results are illustrated using real-world data collected from a typical German dispatch center in Cottbus ("Leitstelle Lausitz"). We identified the Pólya distribution as being superior to the Poisson distribution in describing the call arrival rate and the Weibull distribution to be more suitable than the exponential distribution for interarrival times and service times. However, the commonly used distributions offer acceptable approximations. This is important for estimating a sufficient staffing level in practice using, e.g., the Erlang-C model.

  1. Three faces of entropy for complex systems: Information, thermodynamics, and the maximum entropy principle

    Science.gov (United States)

    Thurner, Stefan; Corominas-Murtra, Bernat; Hanel, Rudolf

    2017-09-01

    There are at least three distinct ways to conceptualize entropy: entropy as an extensive thermodynamic quantity of physical systems (Clausius, Boltzmann, Gibbs), entropy as a measure for information production of ergodic sources (Shannon), and entropy as a means for statistical inference on multinomial processes (Jaynes maximum entropy principle). Even though these notions represent fundamentally different concepts, the functional form of the entropy for thermodynamic systems in equilibrium, for ergodic sources in information theory, and for independent sampling processes in statistical systems, is degenerate, H (p ) =-∑ipilogpi . For many complex systems, which are typically history-dependent, nonergodic, and nonmultinomial, this is no longer the case. Here we show that for such processes, the three entropy concepts lead to different functional forms of entropy, which we will refer to as SEXT for extensive entropy, SIT for the source information rate in information theory, and SMEP for the entropy functional that appears in the so-called maximum entropy principle, which characterizes the most likely observable distribution functions of a system. We explicitly compute these three entropy functionals for three concrete examples: for Pólya urn processes, which are simple self-reinforcing processes, for sample-space-reducing (SSR) processes, which are simple history dependent processes that are associated with power-law statistics, and finally for multinomial mixture processes.

  2. Quantum simulation of the integer factorization problem: Bell states in a Penning trap

    Science.gov (United States)

    Rosales, Jose Luis; Martin, Vicente

    2018-03-01

    The arithmetic problem of factoring an integer N can be translated into the physics of a quantum device, a result that supports Pólya's and Hilbert's conjecture to demonstrate Riemann's hypothesis. The energies of this system, being univocally related to the factors of N , are the eigenvalues of a bounded Hamiltonian. Here we solve the quantum conditions and show that the histogram of the discrete energies, provided by the spectrum of the system, should be interpreted in number theory as the relative probability for a prime to be a factor candidate of N . This is equivalent to a quantum sieve that is shown to require only o (ln√{N}) 3 energy measurements to solve the problem, recovering Shor's complexity result. Hence the outcome can be seen as a probability map that a pair of primes solve the given factorization problem. Furthermore, we show that a possible embodiment of this quantum simulator corresponds to two entangled particles in a Penning trap. The possibility to build the simulator experimentally is studied in detail. The results show that factoring numbers, many orders of magnitude larger than those computed with experimentally available quantum computers, is achievable using typical parameters in Penning traps.

  3. msBP: An R Package to Perform Bayesian Nonparametric Inference Using Multiscale Bernstein Polynomials Mixtures

    Directory of Open Access Journals (Sweden)

    Antonio Canale

    2017-06-01

    Full Text Available msBP is an R package that implements a new method to perform Bayesian multiscale nonparametric inference introduced by Canale and Dunson (2016. The method, based on mixtures of multiscale beta dictionary densities, overcomes the drawbacks of Pólya trees and inherits many of the advantages of Dirichlet process mixture models. The key idea is that an infinitely-deep binary tree is introduced, with a beta dictionary density assigned to each node of the tree. Using a multiscale stick-breaking characterization, stochastically decreasing weights are assigned to each node. The result is an infinite mixture model. The package msBP implements a series of basic functions to deal with this family of priors such as random densities and numbers generation, creation and manipulation of binary tree objects, and generic functions to plot and print the results. In addition, it implements the Gibbs samplers for posterior computation to perform multiscale density estimation and multiscale testing of group differences described in Canale and Dunson (2016.

  4. Evolution in the Continuum Morphological Properties of Ly alpha-Emitting Galaxies from Z=3.1 to Z=2.1

    Science.gov (United States)

    Bond, Nicholas A.; Gawiser, Eric; Guaita, Lucia; Padilla, Nelson; Gronwall, Chile Caryl; Ciardullo, Robin; Lai, Kamson

    2011-01-01

    We present a rest-frame ultraviolet morphological analysis of 108 z = 2.1 Lyman Alpha Emitters (LAEs) in the Extended Chandra Deep Field South (ECDF-S) and compare it to a similar sample of 171 LAEs at z = 3.1 . Using Hubble Space Telescope (HST) images taken as part of the Galaxy Evolution From Morphology and SEDs survey, Great Observatories Origins Deep Survey, and Hubble Ultradeep Field surveys, we measure the size and photometric component distributions, where photo- metric components are defined as distinct clumps of UV-continuum emission. At both redshifts, the majority of LAEs have observed half-light radii physical properties derived from its SED. LAEs are found to be larger for galaxies with larger stellar mass, larger star formation rate, and larger dust obscuration, but there is no evidence for a trend between equivalent width and half-light radius at either redshift. The presence of these correlations suggests that a wide range of objects are being selected by LAE surveys at that redshift, including a significant fraction of objects for which a massive and moderately extended population of old stars underlies the young starburst giving rise to the Lya emission.

  5. Inverse Ising problem in continuous time: A latent variable approach

    Science.gov (United States)

    Donner, Christian; Opper, Manfred

    2017-12-01

    We consider the inverse Ising problem: the inference of network couplings from observed spin trajectories for a model with continuous time Glauber dynamics. By introducing two sets of auxiliary latent random variables we render the likelihood into a form which allows for simple iterative inference algorithms with analytical updates. The variables are (1) Poisson variables to linearize an exponential term which is typical for point process likelihoods and (2) Pólya-Gamma variables, which make the likelihood quadratic in the coupling parameters. Using the augmented likelihood, we derive an expectation-maximization (EM) algorithm to obtain the maximum likelihood estimate of network parameters. Using a third set of latent variables we extend the EM algorithm to sparse couplings via L1 regularization. Finally, we develop an efficient approximate Bayesian inference algorithm using a variational approach. We demonstrate the performance of our algorithms on data simulated from an Ising model. For data which are simulated from a more biologically plausible network with spiking neurons, we show that the Ising model captures well the low order statistics of the data and how the Ising couplings are related to the underlying synaptic structure of the simulated network.

  6. Superluminal motion (review)

    Science.gov (United States)

    Malykin, G. B.; Romanets, E. A.

    2012-06-01

    Prior to the development of Special Relativity, no restrictions were imposed on the velocity of the motion of particles and material bodies, as well as on energy transfer and signal propagation. At the end of the 19th century and the beginning of the 20th century, it was shown that a charge that moves at a velocity faster than the speed of light in an optical medium, in particular, in vacuum, gives rise to impact radiation, which later was termed the Vavilov-Cherenkov radiation. Shortly after the development of Special Relativity, some researchers considered the possibility of superluminal motion. In 1923, the Soviet physicist L.Ya. Strum suggested the existence of tachyons, which, however, have not been discovered yet. Superluminal motions can occur only for images, e.g., for so-called "light spots," which were considered in 1972 by V.L. Ginzburg and B.M. Bolotovskii. These spots can move with a superluminal phase velocity but are incapable of transferring energy and information. Nevertheless, these light spots may induce quite real generation of microwave radiation in closed waveguides and create the Vavilov-Cherenkov radiation in vacuum. In this work, we consider various paradoxes, illusions, and artifacts associated with superluminal motion.

  7. PolyaPeak: Detecting Transcription Factor Binding Sites from ChIP-seq Using Peak Shape Information

    Science.gov (United States)

    Wu, Hao; Ji, Hongkai

    2014-01-01

    ChIP-seq is a powerful technology for detecting genomic regions where a protein of interest interacts with DNA. ChIP-seq data for mapping transcription factor binding sites (TFBSs) have a characteristic pattern: around each binding site, sequence reads aligned to the forward and reverse strands of the reference genome form two separate peaks shifted away from each other, and the true binding site is located in between these two peaks. While it has been shown previously that the accuracy and resolution of binding site detection can be improved by modeling the pattern, efficient methods are unavailable to fully utilize that information in TFBS detection procedure. We present PolyaPeak, a new method to improve TFBS detection by incorporating the peak shape information. PolyaPeak describes peak shapes using a flexible Pólya model. The shapes are automatically learnt from the data using Minorization-Maximization (MM) algorithm, then integrated with the read count information via a hierarchical model to distinguish true binding sites from background noises. Extensive real data analyses show that PolyaPeak is capable of robustly improving TFBS detection compared with existing methods. An R package is freely available. PMID:24608116

  8. Quantifying evenly distributed states in exclusion and nonexclusion processes

    Science.gov (United States)

    Binder, Benjamin J.; Landman, Kerry A.

    2011-04-01

    Spatial-point data sets, generated from a wide range of physical systems and mathematical models, can be analyzed by counting the number of objects in equally sized bins. We find that the bin counts are related to the Pólya distribution. New measures are developed which indicate whether or not a spatial data set, generated from an exclusion process, is at its most evenly distributed state, the complete spatial randomness (CSR) state. To this end, we define an index in terms of the variance between the bin counts. Limiting values of the index are determined when objects have access to the entire domain and when there are subregions of the domain that are inaccessible to objects. Using three case studies (Lagrangian fluid particles in chaotic laminar flows, cellular automata agents in discrete models, and biological cells within colonies), we calculate the indexes and verify that our theoretical CSR limit accurately predicts the state of the system. These measures should prove useful in many biological applications.

  9. Classic papers in combinatorics

    CERN Document Server

    Rota, Gian-Carlo

    1987-01-01

    This volume surveys the development of combinatorics since 1930 by presenting in chronological order the fundamental results of the subject proved in over five decades of original papers by:.-T. van Aardenne-Ehrenfest.-R.L. Brooks.-N.G. de Bruijn.-G.F. Clements.-H.H. Crapo.-R.P. Dilworth.-J. Edmonds.-P.Erdös.-L.R. Ford, Jr.-D.R. Fulkerson.-D. Gale.-L. Geissinger.-I.J. Good.-R.L. Graham.-A.W. Hales.-P. Hall.-P.R. Halmos.-R.I. Jewett.-I. Kaplansky.-P.W. Kasteleyn.-G. Katona.-D.J. Kleitman.-K. Leeb.-B. Lindström.-L. Lovász.-D. Lubell.-C. St. J.A. Nash-Williams.-G. Pólya.-F.P. Ramsey.-G.C. Rota.-B.L. Rothschild.-H.J. Ryser.-C. Schensted.-M.P. Schützenberger.-R.P. Stanley.-G. Szekeres.-W.T. Tutte.-H.E. Vaughan.-H. Whitney.

  10. 7th International Conference on General Inequalities

    CERN Document Server

    Everitt, William; Losonczi, Laszlo; Walter, Wolfgang

    1997-01-01

    Inequalities continue to play an essential role in mathematics. The subject is per­ haps the last field that is comprehended and used by mathematicians working in all the areas of the discipline of mathematics. Since the seminal work Inequalities (1934) of Hardy, Littlewood and P6lya mathematicians have laboured to extend and sharpen the earlier classical inequalities. New inequalities are discovered ev­ ery year, some for their intrinsic interest whilst others flow from results obtained in various branches of mathematics. So extensive are these developments that a new mathematical periodical devoted exclusively to inequalities will soon appear; this is the Journal of Inequalities and Applications, to be edited by R. P. Agar­ wal. Nowadays it is difficult to follow all these developments and because of lack of communication between different groups of specialists many results are often rediscovered several times. Surveys of the present state of the art are therefore in­ dispensable not only to mathematici...

  11. A Proposal of Categorisation for Analysing Inductive Reasoning (Una Propuesta de Categorización para Analizar el Razonamiento Inductivo

    Directory of Open Access Journals (Sweden)

    Encarnación Castro

    2007-01-01

    Full Text Available We present an analysis of the inductive reasoning of twelve Spanish secondary students in a mathematical problem-solving context. Students were interviewed while they worked on two different problems. Based on Polya´s steps and Reid’s stages for a process of inductive reasoning, we propose a more precise categorization for analyzing this kind of reasoning in our particular context. In this paper we present some results of a wider investigation (Cañadas, 2002.Presentamos un análisis del razonamiento inductivo de doce estudiantes de educación secundaria en un contexto de resolución de problemas matemáticos. Los estudiantes fueron entrevistados mientras trabajaban en dos problemas diferentes. Basándonos en los pasos considerados por Pólya y Reid para un proceso de razonamiento inductivo, proponemos una categorización más precisa para analizar este tipo de razonamiento en nuestro contexto particular. En este documento presentamos algunos resultados de una investigación más amplia (Cañadas, 2002.

  12. Micro-Mechanical Voltage Tunable Fabry-Perot Filters Formed in (111) Silicon. Degree awarded by Colorado Univ., Boulder, CO

    Science.gov (United States)

    Patterson, James D.

    1997-01-01

    The MEMS (Micro-Electro-Mechanical-Systems) technology is quickly evolving as a viable means to combine micro-mechanical and micro-optical elements on the same chip. One MEMS technology that has recently gained attention by the research community is the micro-mechanical Fabry-Perot optical filter. A MEMS based Fabry-Perot consists of a vertically integrated structure composed of two mirrors separated by an air gap. Wavelength tuning is achieved by applying a bias between the two mirrors resulting in an attractive electrostatic force which pulls the mirrors closer. In this work, we present a new micro-mechanical Fabry-Perot structure which is simple to fabricate and is integratable with low cost silicon photodetectors and transistors. The structure consists of a movable gold coated oxide cantilever for the top mirror and a stationary Au/Ni plated silicon bottom mirror. The fabrication process is single mask level, self aligned, and requires only one grown or deposited layer. Undercutting of the oxide cantilever is carried out by a combination of RIE and anisotropic KOH etching of the (111) silicon substrate. Metallization of the mirrors is provided by thermal evaporation and electroplating. The optical and electrical characteristics of the fabricated devices were studied and show promissing results. A wavelength shift of 120nm with 53V applied bias was demonstrated by one device geometry using 6.27 micrometer air gap. The finesse of the structure was 2.4. Modulation bandwidths ranging from 91KHz to greater than 920KHz were also observed. Theoretical calculations show that if mirror reflectivity, smoothness, and parallelism are improved, a finesse of 30 is attainable. The predictions also suggest that a reduction of the air gap to 1 micrometer results in an increased wavelength tuning range of 175 nm with a CMOS compatible 4.75V.

  13. Processing of nanocrystalline diamond thin films for thermal management of wide-bandgap semiconductor power electronics

    International Nuclear Information System (INIS)

    Govindaraju, N.; Singh, R.N.

    2011-01-01

    Highlights: → Studied effect of nanocrystalline diamond (NCD) deposition on device metallization. → Deposited NCD on to top of High Electron Mobility Transistors (HEMTs) and Si devices. → Temperatures below 290 deg. C for Si devices and 320 deg. C for HEMTs prevent metal damage. → Development of novel NCD-based thermal management for power electronics feasible. - Abstract: High current densities in wide-bandgap semiconductor electronics operating at high power levels results in significant self-heating of devices, which necessitates the development thermal management technologies to effectively dissipate the generated heat. This paper lays the foundation for the development of such technology by ascertaining process conditions for depositing nanocrystalline diamond (NCD) on AlGaN/GaN High Electron Mobility Transistors (HEMTs) with no visible damage to device metallization. NCD deposition is carried out on Si and GaN HEMTs with Au/Ni metallization. Raman spectroscopy, optical and scanning electron microscopy are used to evaluate the quality of the deposited NCD films. Si device metallization is used as a test bed for developing process conditions for NCD deposition on AlGaN/GaN HEMTs. Results indicate that no visible damage occurs to the device metallization for deposition conditions below 290 deg. C for Si devices and below 320 deg. C for the AlGaN/GaN HEMTs. Possible mechanisms for metallization damage above the deposition temperature are enumerated. Electrical testing of the AlGaN/GaN HEMTs indicates that it is indeed possible to deposit NCD on GaN-based devices with no significant degradation in device performance.

  14. Microstructure evolution of the Si{sub 3}N{sub 4}/Si{sub 3}N{sub 4} joints brazed using Au-Ni-V filler alloys with different V content

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Y. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Zhang, J., E-mail: hitzhangjie@hit.edu.cn [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Zhang, H.W.; Fan, G.H.; He, Y.M. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2011-08-18

    Highlights: > Si{sub 3}N{sub 4} ceramic was brazed using Au-Ni-V filler alloy with different V content. > The microstructure evolution of the joint was study in detail in the paper. > The polygonal Ni{sub 2}SiV{sub 3} and Ni{sub 3}V phase in the joint were investigated by TEM. > The formation of different compounds and alloys in joint was detailed discussed. - Abstract: Au-Ni-V filler alloys with different vanadium contents were designed to braze Si{sub 3}N{sub 4} ceramic at 1373 K for 30 min, and the microstructures of brazing seams were investigated by SEM and TEM. When the Au-Ni-V filler alloy contains 5 at.% V, round-like Ni[Si, V, Au] precipitates form in the Au[Ni] solid solution matrix and a VN reaction layer with 0.5 {mu}m thickness appears on Si{sub 3}N{sub 4} interface. When the V content increases to 10 at.%, a new polygonal Ni{sub 2}SiV{sub 3} phase occurs in the seam, and the Ni[Si, V, Au] precipitate coarsens and VN layer thickens. With increase of V contents to 15 and 20 at.%, laminar Ni[Au] and polygonal Ni{sub 3}V precipitates form. With 25 at.% V content in the filler alloy, the Ni{sub 2}SiV{sub 3} and Ni{sub 3}V precipitates distribute homogenously in the brazing seam. These microstructure evolutions were attributed to the reaction between Si{sub 3}N{sub 4} and vanadium, which forms VN reaction layer and releases Si into the molten alloy.

  15. A new method of making ohmic contacts to p-GaN

    Energy Technology Data Exchange (ETDEWEB)

    Hernández-Gutierrez, C.A., E-mail: chernandez@fis.cinvestav.mx [DNyN, Cinvestav-IPN, México, DF, 07360 (Mexico); Kudriavtsev, Yu. [Departamento Ingeniería Eléctrica – SEES, Cinvestav-IPN, México, DF, 07360 (Mexico); Mota, Esteban [ESIME, Instituto Politécnico Nacional, México, DF, 07738 (Mexico); Hernández, A.G.; Escobosa-Echavarría, A.; Sánchez-Resendiz, V. [Departamento Ingeniería Eléctrica – SEES, Cinvestav-IPN, México, DF, 07360 (Mexico); Casallas-Moreno, Y.L.; López-López, M. [Departamento Física, Cinvestav-IPN, México, DF, 07360 (Mexico)

    2016-12-01

    Highlights: • Low resistance Ohmic contacts preparation is based on low energy high dose In{sup +} ion implantation into Metal/p-GaN to achieve a thin layer of In{sub x}Ga{sub 1-x}N just at the interface. • The specific ohmic contact was reduced from 10{sup −2} Ωcm{sup 2} to 2.5 × 10{sup −4} Ωcm{sup 2}. - Abstract: The structural, chemical, and electrical characteristics of In{sup +} ion-implanted Au/Ni, Au/Nb and Au/W ohmic contacts to p-GaN were investigated. After the preparation of Ni, Nb and W electrode on the surface of p-GaN, the metal/p-GaN contact interface was implanted by 30 keV In{sup +} ions with an implantation dose of 5 × 10{sup 15} ions/cm{sup 2} at room temperature to form a thin layer of In{sub x}Ga{sub 1-x}N located at the metal-semiconductor interface, achieved to reduce the specific contact resistance due to the improving quantum tunneling transport trough to the structure. The characterization was carried out by high-resolution X-ray diffraction, scanning electron microscopy, Raman spectroscopy, and secondary ion mass spectrometry to investigate the formation of ternary alloy, re-crystallization by rapid thermal annealing process after In{sup +} implantation, and the redistribution of elements. The specific contact resistance was extracted by current-voltage (I-V) curves using transmission line method; the lowest specific contact resistance of 2.5 × 10{sup −4} Ωcm{sup 2} was achieved for Au/Ni/p-In{sub x}Ga{sub 1-x}N/p-GaN ohmic contacts.

  16. Solar Lyman-Alpha Polarization Observation of the Chromosphere and Transition Region by the Sounding Rocket Experiment CLASP

    Science.gov (United States)

    Narukage, Noriyuki; Kano, Ryohei; Bando, Takamasa; Ishikawa, Ryoko; Kubo, Masahito; Katsukawa, Yukio; Ishikawa, Shinnosuke; Hara, Hiroshi; Suematsu, Yoshinori; Giono, Gabriel; hide

    2015-01-01

    We are planning an international rocket experiment Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is (2015 planned) that Lyman a line (Ly(alpha) line) polarization spectroscopic observations from the sun. The purpose of this experiment, detected with high accuracy of the linear polarization of the Ly(alpha) lines to 0.1% by using a Hanle effect is to measure the magnetic field of the chromosphere-transition layer directly. For polarization photometric accuracy achieved that approx. 0.1% required for CLASP, it is necessary to realize the monitoring device with a high throughput. On the other hand, Ly(alpha) line (vacuum ultraviolet rays) have a sensitive characteristics that is absorbed by the material. We therefore set the optical system of the reflection system (transmission only the wavelength plate), each of the mirrors, subjected to high efficiency of the multilayer coating in accordance with the role. Primary mirror diameter of CLASP is about 30 cm, the amount of heat about 30,000 J is about 5 minutes of observation time is coming mainly in the visible light to the telescope. In addition, total flux of the sun visible light overwhelmingly large and about 200 000 times the Ly(alpha) line wavelength region. Therefore, in terms of thermal management and 0.1% of the photometric measurement accuracy achieved telescope, elimination of the visible light is essential. We therefore, has a high reflectivity (> 50%) in Lya line, visible light is a multilayer coating be kept to a low reflectance (Science was achieved a high throughput as a device for a vacuum ultraviolet ray of the entire system less than 5% (CCD of QE is not included).

  17. Wright-Fisher diffusion bridges.

    Science.gov (United States)

    Griffiths, Robert C; Jenkins, Paul A; Spanò, Dario

    2017-10-06

    The trajectory of the frequency of an allele which begins at x at time 0 and is known to have frequency z at time T can be modelled by the bridge process of the Wright-Fisher diffusion. Bridges when x=z=0 are particularly interesting because they model the trajectory of the frequency of an allele which appears at a time, then is lost by random drift or mutation after a time T. The coalescent genealogy back in time of a population in a neutral Wright-Fisher diffusion process is well understood. In this paper we obtain a new interpretation of the coalescent genealogy of the population in a bridge from a time t∈(0,T). In a bridge with allele frequencies of 0 at times 0 and T the coalescence structure is that the population coalesces in two directions from t to 0 and t to T such that there is just one lineage of the allele under consideration at times 0 and T. The genealogy in Wright-Fisher diffusion bridges with selection is more complex than in the neutral model, but still with the property of the population branching and coalescing in two directions from time t∈(0,T). The density of the frequency of an allele at time t is expressed in a way that shows coalescence in the two directions. A new algorithm for exact simulation of a neutral Wright-Fisher bridge is derived. This follows from knowing the density of the frequency in a bridge and exact simulation from the Wright-Fisher diffusion. The genealogy of the neutral Wright-Fisher bridge is also modelled by branching Pólya urns, extending a representation in a Wright-Fisher diffusion. This is a new very interesting representation that relates Wright-Fisher bridges to classical urn models in a Bayesian setting. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Probing HeII Reionization at z>3.5 with Resolved HeII Lyman Alpha Forest Spectra

    Science.gov (United States)

    Worseck, Gabor

    2017-08-01

    The advent of GALEX and COS have revolutionized our view of HeII reionization, the final major phase transition of the intergalactic medium. COS spectra of the HeII Lyman alpha forest have confirmed with high confidence the high HeII transmission that signifies the completion of HeII reionization at z 2.7. However, the handful of z>3.5 quasars observed to date show a set of HeII transmission 'spikes' and larger regions with non-zero transmission that suggest HeII reionization was well underway by z=4. This is in striking conflict with predictions from state-of-the-art radiative transfer simulations of a HeII reionization driven by bright quasars. Explaining these measurements may require either faint quasars or more exotic sources of hard photons at z>4, with concomitant implications for HI reionization. However, many of the observed spikes are unresolved in G140L spectra and are significantly impacted by Poisson noise. Current data cannot reliably probe the ionization state of helium at z>3.5.We request 41 orbits to obtain science-grade G130M spectra of the two UV-brightest HeII-transmitting QSOs at z>3.5 to confirm and resolve their HeII transmission spikes as an unequivocal test of early HeII reionization. These spectra are complemented by recently obtained data from 8m telescopes: (1) Echelle spectra of the coeval HI Lya forest to map the underlying density field that modulates the HeII absorption, and (2) Our dedicated survey for foreground QSOs that may source the HeII transmission. Our recent HST programs revealed the only two viable targets to resolve the z>3.5 HeII Lyman alpha forest, and to conclusively solve this riddle.

  19. Functional capacity, physical activity, and quality of life in hypoxemic patients with chronic obstructive pulmonary disease

    Directory of Open Access Journals (Sweden)

    Saglam M

    2015-02-01

    Full Text Available Melda Saglam,1 Naciye Vardar-Yagli,1 Sema Savci,2 Deniz Inal-Ince,1 Ebru Calik Kutukcu,1 Hülya Arikan,1 Lutfi Coplu3 1Department of Physiotherapy and Rehabilitation, Faculty of Health Sciences, Hacettepe University, Ankara, Turkey; 2School of Physiotherapy and Rehabilitation, Dokuz Eylul University, Izmir, Turkey; 3Department of Chest Medicine, Faculty of Medicine, Hacettepe University, Ankara, Turkey Background: The risk of hypoxemia increases with the progression of chronic obstructive pulmonary disease (COPD and the deterioration of pulmonary function. The aim of this study was to compare functional capacity, physical activity, and quality of life in hypoxemic and non-hypoxemic patients with COPD.Methods: Thirty-nine COPD patients (mean age: 62.0±7.03 years were included in this study. Arterial blood gas tensions were measured, and patients were divided into two groups according to oxygen partial pressure (PaO2, the hypoxemic COPD (PaO2 <60 mmHg (n=18, and the control (PaO2 ≥60 mmHg (n=21 groups. Functional exercise capacity was evaluated using the 6-minute walk test (6MWT. Oxygen saturation, dyspnea, and fatigue perception were measured before and after the 6MWT. Physical activity was assessed using the International Physical Activity Questionnaire (IPAQ and an accelerometer. Quality of life was assessed using the St George’s Respiratory Questionnaire (SGRQ.Results: The number of emergency visits and hospitalizations were higher in hypoxemic patients (P<0.05. Lung function parameters, 6MWT distance, exercise oxygen saturation, IPAQ total score, and energy expenditure during daily life were significantly lower, but percentage of maximum heart rate reached during the 6MWT was significantly higher, in hypoxemic COPD patients than in controls (P<0.05.Conclusion: Hypoxemia has a profound effect on functional capacity and physical activity in patients with COPD. Keywords: COPD, hypoxemia, 6-minute walk test

  20. Virtual libraries of tetrapyrrole macrocycles. Combinatorics, isomers, product distributions, and data mining.

    Science.gov (United States)

    Taniguchi, Masahiko; Du, Hai; Lindsey, Jonathan S

    2011-09-26

    A software program (PorphyrinViLiGe) has been developed to enumerate the type and relative amounts of substituted tetrapyrrole macrocycles in a virtual library formed by one of four different classes of reactions. The classes include (1) 4-fold reaction of n disubstituted heterocycles (e.g., pyrroles or diiminoisoindolines) to form β-substituted porphyrins, β-substituted tetraazaporphyrins, or α- or β-substituted phthalocyanines; (2) combination of m aminoketones and n diones to form m × n pyrroles, which upon 4-fold reaction give β-substituted porphyrins; (3) derivatization of an 8-point tetrapyrrole scaffold with n reagents, and (4) 4-fold reaction of n aldehydes and pyrrole to form meso-substituted porphyrins. The program accommodates variable ratios of reactants, reversible or irreversible reaction (reaction classes 1 and 2), and degenerate modes of formation. Pólya's theorem (for enumeration of cyclic entities) has also been implemented and provides validation for reaction classes 3 and 4. The output includes the number and identity of distinct reaction-accessible substituent combinations, the number and identity of isomers thereof, and the theoretical mass spectrum. Provisions for data mining enable assessment of the number of products having a chosen pattern of substituents. Examples include derivatization of an octa-substituted phthalocyanine with eight reagents to afford a library of 2,099,728 members (yet only 6435 distinct substituent combinations) and reversible reaction of six distinct disubstituted pyrroles to afford 2649 members (yet only 126 distinct substituent combinations). In general, libraries of substituted tetrapyrrole macrocycles occupy a synthetically accessible region of chemical space that is rich in isomers (>99% or 95% for the two examples, respectively).

  1. A Study of Inner Disk Gas around Young Stars in the Lupus Complex

    Science.gov (United States)

    Arulanantham, Nicole Annemarie; France, Kevin; Hoadley, Keri

    2018-06-01

    We present a study of molecular hydrogen at the surfaces of the disks around five young stars in the Lupus complex: RY Lupi, RU Lupi, MY Lupi, Sz 68, and TYC 7851. Each system was observed with the Cosmic Origins Spectrograph (COS) onboard the Hubble Space Telescope (HST), and we detect a population of fluorescent H2 in all five sources. The temperatures required for LyA fluorescence to proceed (T ~ 1500-2500 K) place the gas within ~15 AU of the central stars. We have used these features to extract the radial distribution of H2 in the inner disk, where planet formation may already be taking place. The objects presented here have very different outer disk morphologies, as seen by ALMA via 890 micron dust continuum emission, ranging from full disks with no signs of cavities to systems with large regions that are clearly depleted (e.g. TYC 7851, with a cavity extending to 75 and 60 AU in dust and gas, respectively). Our results are interpreted in conjunction with sub-mm data from the five systems in an effort to piece together a more complete picture of the overall disk structure. We have previously applied this multi-wavelength approach to RY Lupi, including 4.7 micron IR-CO emission in our analysis. These IR-CO and UV-H2 observations were combined with 10 micron silicate emission, the 890 micron dust continuum, and 1.3 mm CO observations from the literature to infer a gapped structure in the inner disk. This single system has served as a testing ground for the larger Lupus complex sample, which we compare here to examine any trends between the outer disk morphology and inner disk gas distributions.

  2. X-ray/UV Observing Campaign on the Mrk 279 AGN Outflow: A Global Fitting Analysis of the UV Absorption

    Energy Technology Data Exchange (ETDEWEB)

    Gabel, J.

    2005-03-17

    We present an analysis of the intrinsic UV absorption in the Seyfert 1 galaxy Mrk 279 based on simultaneous long observations with the ''Hubble Space Telescope'' (41 ks) and the ''Far Ultraviolet Spectroscopic Explorer'' (91 ks). To extract the line-of-sight covering factors and ionic column densities, we separately fit two groups of absorption lines: the Lyman series and the CNO lithium-like doublets. For the CNO doublets we assume that all three ions share the same covering factors. The fitting method applied here overcomes some limitations of the traditional method using individual doublet pairs; it allows for the treatment of more complex, physically realistic scenarios for the absorption-emission geometry and eliminates systematic errors that we show are introduced by spectral noise. We derive velocity-dependent solutions based on two models of geometrical covering--a single covering factor for all background emission sources, and separate covering factors for the continuum and emission lines. Although both models give good statistical fits to the observed absorption, we favor the model with two covering factors because: (a) the best-fit covering factors for both emission sources are similar for the independent Lyman series and CNO doublet fits; (b) the fits are consistent with full coverage of the continuum source and partial coverage of the emission lines by the absorbers, as expected from the relative sizes of the nuclear emission components; and (c) it provides a natural explanation for variability in the Lya absorption detected in an earlier epoch. We also explore physical and geometrical constraints on the outflow from these results.

  3. Microstructure and interfacial behaviour of Alumina/Inconel 600 joints prepared by brazing route

    International Nuclear Information System (INIS)

    Laik, A.; Mishra, P.; Bhanumurthy, K.; Kashyap, B.P.

    2010-01-01

    Joining of metals to ceramics remains a technological challenge due to the wide difference in the physical and mechanical properties of the two classes of materials. Attempt was made to produce leak tight joints between Inconel-600 and alumina using the brazing route with Au-Ni brazing alloy. Alumina tubes were metallised following the Mo-Mn route and then coated with Ni. The metallised alumina tubes were brazed to Inconel-600 ferrules using Au-18%Ni brazing alloy under vacuum, at optimised process parameters. In order to study the effect of prolong annealing on the microstructural stability and the micro-chemistry of the brazing zone, brazed joints were subjected to prolong annealing at 400 deg C and 560 deg C for 8000 hrs each. Detailed analysis of the interfacial structure of the brazing zones was done using an electron probe microanalyser (EPMA). X-ray maps of the elements Fe, Ni, Cr, Al, Au, Mo and Mn along with BSE images of the brazing zone are given. These X-ray maps precisely reveal the micro-chemistry of the brazing zones. The various phases formed were identified. The distribution of the various elements across the interfaces was also obtained, which helps to reveal the chemical behaviour of the individual elements during the process of brazing. Two phases appear very distinctly in the brazement, one is rich in Au and the other is rich in Ni. Depending upon their affinity, rest of the elements shows a partitioning in these two phases. While Fe, Cr and Mo get dissolved in the Ni-rich phase, Mn seems to partition in the Au-rich phase. The microstructure and the X-ray maps of the couple annealed at 400 deg C shows that the spatial variation in the composition throughout the brazing zone gets homogenised due to diffusion at high temperatures. This effect is even more pronounced on annealing at 560 deg C. Moreover, the transport of Cr from the Inconel side to the surface of alumina is very evident. On annealing at 560 deg C, a region rich in Cr, was found to

  4. Anisotropic nanomaterials: Synthesis, optical and magnetic properties, and applications

    Science.gov (United States)

    Banholzer, Matthew John

    encapsulation on the SPR of these structures. Chapter six focuses on the magnetic properties of Au-Ni heterostructures. In addition to demonstration of nanoconfinement effects based upon the anisotropy of the nanorods/nanodisk structure, the magnetic coupling of rod-disk heterostructures is examined. Subsequent investigations suggest that the magnetic behavior of disks can be influenced by nearby rod segments, leading to the creation of a three-state spin system that may prove useful in device applications.

  5. Reseñas de Libros

    Directory of Open Access Journals (Sweden)

    José Antonio Ruiz Gil

    2009-12-01

    Full Text Available Beck, Ulrich; Grande, Edgar, La Europa Cosmopolita. Sociedad y Política en la Segunda Modernidad. Barcelona, Paidós, 2006, 392 pp.Páginas 187-189José Antonio Ruiz GilCastells, Manuel (ed., La sociedad red: una visión global. Madrid, Alianza Editorial, 2006, 558 pp.Páginas 189-191David Molina RabadánCuenca Toribio, José Manuel, Nacionalismo, Franquismo y Nacionalcatolicismo. Madrid, Editorial Actas, 2008, 220 pp.Páginas 191-193Ricardo Martín de la GuardiaDiamond, Jared, Colapso, Por qué unas sociedades perduran y otras desaparecen. Madrid, Debate, 2006, 854 pp.Páginas 193-195Daniel Alcalde GüelfoFumaroli, Marc, El Estado cultural (ensayo sobre una religión moderna. Barcelona, Acantilado, 2007, 147 pp.Páginas 195-197José Antonio Ruiz GilGarí, Manuel; Pastor, Jaime y Romero, Miguel (eds., 1968. El mundo pudo cambiar de base. Madrid, Los Libros de la Catarata, 2008, 365 pp.Páginas 197-199Ana Domínguez RamaMann, James, Los Vulcanos. El gabinete de guerra de Bush: Cheney, Powell, Rumsfeld, Rice, Wolfowitz, Armitage. Granada, Almed, 2007, 498 pp.Páginas 199-201David Molina RabadánMartín Muñoz, Gema, Iraq. Un fracaso de Occidente (1920-2003. Barcelona, Tusquets, 2003, 323 pp.Páginas 201-202José María Torrente GisbertMuñoz Aunión, Antonio, La política común europea de derecho de asilo. Valencia, Tirant Lo Blanc. 2007, 268 pp.Páginas 202-205José Joaquín Fernández AllesRey Tristán, Eduardo (dir., Memorias de la violencia en Uruguay y Argentina. Golpes, dictaduras, exilios (1973-2006. Santiago de Compostela, Universidad de Santiago de Compostela-CIEAM, 2007, 382 pp.Páginas 205-206Silvina JensenShlaim, Avi, El Muro de Hierro. Israel y el mundo árabe. Granada, Almed, 2003, 778 pp.Páginas 207-208José María Torrente GisbertWallerstein, Immanuel, Utopística o las opciones históricas del siglo XXI. Madrid, Siglo XXI Editores, 1998, 91 pp.Páginas 208-209Manuel Pérez Salinas

  6. Characterizing the Interstellar and Circumgalactic Medium in Star-forming Galaxies

    Science.gov (United States)

    Du, Xinnan; Shapley, Alice; Crystal Martin, Alison Coil, Charles Steidel, Tucker Jones, Daniel Stark, Allison Strom

    2018-01-01

    Rest-frame UV and optical spectroscopy provide valuable information on the physical properties of the neutral and ionized interstellar medium (ISM) in star-forming galaxies, including both the systemic interstellar component originating from HII regions, and the multi-phase outflowing component associated with star-formation feedback. My thesis focuses on both the systemic and outflowing ISM in star-forming galaxies at redshift z ~ 1-4. With an unprecedented sample at z~1 with the rest-frame near-UV coverage, we examined how the kinematics of the warm and cool phrases of gas, probed by the interstellar CIV and low-ionization features, respectively, relate to each other. The spectral properties of CIV strongly correlate with the current star-formation rate, indicating a distinct nature of highly-ionized outflowing gas being driven by massive star formation. Additionally, we used the same set of z~1 galaxies to study the properties of the systemic ISM in HII regions by analyzing the nebular CIII] emission. CIII] emission tends to be stronger in lower-mass, bluer, and fainter galaxies with lower metallicity, suggesting that the strong CIII] emitters at lower redshifts can be ideal analogs of young, bursty galaxies at z > 6, which are possibly responsible for reionizing the universe. We are currently investigating the redshift evolution of the neutral, circumgalactic gas in a sample of ~1100 Lyman Break Galaxies at z ~ 2-4. The negative correlation between Lya emission and low-ionization interstellar absorption line strengths appears to be universal across different redshifts, but the fine-structure line emitting regions are found to be more compact for higher-redshift galaxies. With the detailed observational constraints provided by the rest-UV and rest-optical spectroscopy, our study sheds light on how the interstellar and circumgalactic gas components and different phases of gas connect to each other, and therefore provides a comprehensive picture of the overall

  7. SPHEREx: Understanding the Origin and Evolution of Galaxies Through the Extragalactic Background Light

    Science.gov (United States)

    Zemcov, Michael; SPHEREx Science Team

    2018-01-01

    Euclid survey, uniquely SPHEREx will enable tomography of cosmic large scale structure using line tracers such as Lya, Ha, Hb, O[II] and O[III], as highlighted in community workshops and AAS special sessions over the past several years.

  8. Geometric characterization for the least Lagrangian action of n-body problems

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Shiqing

    2001-01-01

    [1]Manev, G., La gravitation et l'énergie au zéro, Comptes Rendus, 924, 78: 259.[2]Diacu, F. N., Near-collision dynamics for particle systems with quasihomogeneous potentials, J. of Diff. Equ., 996, 28: 58.[3]Ambrosetti, A., Coti Zelati, V., Periodic Solutions of Singular Lagrangian Systems, Basel: Birkhuser, 993.[4]Arnold, V., Kozlov, V., Neishtadt, A., Dynamical Systems (iii): Mathematical Aspects of Classical and Celestial Mechanics, Berlin: Springer-Verlag, 988.[5]Chenciner, A., Desolneux, N., Minima de l'intégrale d'action et équilibres relatifs de n corps, C R Acad. Sci. Paris, serie I, 998, 326: 209.[6]Coti Zelati, V., The periodic solutions of n-body type problems, Ann IHP Anal nonlinéaire, 990, 7: 477.[7]Euler, L., De motu rectilineo trium corprum se mutuo attrahentium, Novi. Comm. Acad. Sci. Imp. Petropll, 767: 45.[8]Gordon, W., A minimizing property of Keplerian orbits, Amer. J. Math., 977, 99: 96.[9]Lagrange, J., Essai sur le problé me des trois corps, 772, Ouvres, 783, 3: 229.[10]Long, Y., Zhang, S. Q., Geometric characterization for variational minimization solutions of the 3-body problem, Chinese Science Bulletin, 999, 44(8): 653.[11]Long, Y., Zhang, S. Q., Geometric characterization for variational minimization solutions of the 3-body problem with fixed energy, J. of Diff. Equ., 2000, 60: 422.[12]Meyer, K., Hall, G., Introduction to Hamiltonian systems and the n-body problems, Berlin: Springer-Verlag,992.[13]Serra, E., Terracini, S., Collisionless periodic solutions to some three-body problems, Arch. Rational Mech. Anal., 992, 20: 305.[14]Siegle, C., Moser, J., Lectures on Celestial Mechanics, Berlin: Springer-Verlag, 97.[15]Wintner, A., Analytical Foundations of Celestial Mechanics, Princeton: Princeton University Press, 94.[16]Hardy, G., Littlewood, J., Pólya, G., Inequalities, 2nd ed., Cambridge: Combridge University Press, 952.

  9. Características de carcaça de cordeiros Ideal e cruzas Border Leicester X Ideal submetidos a três sistemas alimentares Carcass characteristics of Polwarth and Border Leicester crossbred lambs in three feed systems

    Directory of Open Access Journals (Sweden)

    Henrique Silla Lopes de Almeida

    2006-10-01

    crossing for the variables hot carcass weight (HCW, hot carcass yield (HCY, cold carcass weight (CCW, cold carcass yield (CCY, loin eye area (LYA, sholder weight (PW and leg weight (LW. The crossbreeding between the Border Leicester and Polwarth resulted in superior carcass weight and yields and reduction of the deposition of fat.

  10. Características de carcaça, componentes não-carcaça e composição tecidual e química da 12ª costela de cordeiros Santa Inês terminados em pasto com três gramíneas no período seco Carcass traits, non-carcass components and tissues and chemical composition the 12th rib of Santa Inês sheep finished on three different grasses during the dry season

    Directory of Open Access Journals (Sweden)

    Luizângele Figueiredo de Oliveira Menezes

    2008-07-01

    mais satisfatório em comparação aos terminados em pasto de capim-andropogon.Carcass traits, non-carcass components and 12th rib yield of Santa Inês sheep finished in rotational grazing with three different tropical grasses (A. gayanus Kunth. cv. Planaltina, P. maximum Jacq. cv. Aruana and P. maximum Jacq. cv. Tanzania were evaluated in the dry season of the year. A completely randomized design with 11 sheep (3 months old and 18.8 ± 2.88 kg LW in each treatment was used. Animals were supplemented with increasing levels of concentrate, as advancing of the dry season, besides ad libitum mineral salt. At the end of 82 days of experiment, the animals were slaughtered, in the previous day of the slaughter; loin eye area (LYA was measured using ultra-sound (EMUS. Carcasses were evaluated for slaughter weight (SW, hot carcass weight (HCW, hot carcass dressing (HCD, carcass length (CL, subcutaneous fat score (SFATS, hot half carcass weight (HHCW, half carcass cuts (Rib/Belly, Rack, Back, Shoulder, Leg and Neck, skin weight (SKIN, thoracic (TV and abdominal (AV viscera and testicular (TE. The 12th rib was evaluated for total weight (TW, LYA, amount and percentage of muscle (MUSC, bone (BONE and fat (FAT as well as chemical composition. The characteristics SW, HCD, HHCW, SKIN and FAT did not differ between animals finished on Aruana and Tanzania grass, however were superior to those on andropogon grass. The yields on Neck, Rib/Belly and Rack in animals finished in tanzânia grass was superior to those on andropogon grass and aruana grass, which did not differ between itself. The other carcass traits, non-carcass components and 12th rib analyses did not differ between treatments. Sheep kept on aruana grass and tanzania grass howed better carcass traits with more satisfactory production levels when compared to the animals finished on andropogon grass.

  11. Meta-Analysis of Suicide-Related Behavior or Ideation in Child, Adolescent, and Adult Patients Treated with Atomoxetine

    Science.gov (United States)

    Wietecha, Linda A.; Wang, Shufang; Buchanan, Andrew S.; Kelsey, Douglas K.

    2014-01-01

    and 9 adult clinical trials completed between 1998 and 2011. Ten pediatric (Studies HFBD, HFBK, LYAC, LYAS, LYAT, LYAW, LYAX, LYBG, LYBI, and LYBP) and two adult trials (Studies LYAA and LYAO) were conducted before the requirement to post trials at initiation (ongoing as of July 1, 2005) and, therefore, do not have a registration number. The registration numbers for the 13 pediatric trials meeting this requirement are: NCT00191698 (LYBX), NCT00486122 (LYCC), NCT00386581 (LYCZ), NCT00485459 (S010), NCT00191542 (LY15), NCT00191295 (LYBC), NCT00191906 (LYCK), NCT00192023 (LYCY), NCT00191945 (LYDM), NCT00546910 (LYDV), NCT00406354 (LYDW), NCT00380692 (S017), and NCT00607919 (LYEB). For the seven adult trials, the registration numbers are: NCT00190931 (LYBV), NCT00190957 (LYBY), NCT00190736 (LYCU), NCT00190775 (LYCW), NCT00190879 (LYDQ), NCT00510276 (LYDZ), and NCT00962104 (LYEE). PMID:25019647

  12. Azebaycan’ın İlk Savaş Pilotu Ferruh Ağa GayıbovThe First Combat Pilot of Azerbaijan- Farrukh Gayıbov-

    Directory of Open Access Journals (Sweden)

    MUHAMMET KEMALOĞLU

    2014-06-01

    Full Text Available Ferruh Ağa Gayıbov Azerbaycanlı ilk şavaş pilotudur. İlya Muromets №16 adlı bombardıman uçağının personelidir. I.Dünya Savaşına katılmıştır. Çar ordusunda “Topçuların Tanrısı” diye kabul edilen Aliağa Şıhlinski’nin de akrabasıdır. Ferruh Ağa 2 Ekim 1891’de, Kazak ilinin Sınır Salahlı köyünde doğmuştur. Tiflis Askeri Okulunda okur. Üsteğmen rütbesinde iken 12 Eylül 1916’da Batı cephesi karargâhının emri ile Borına’ya saldırır, Almanların mevzilerini ve mevkilerini bombalar. Onun uçağına doğru 4 alman savaş uçağı saldırıya geçer. Gayıbov onların üçünü imha eder ancak uçağının aldığı darebeden dolayı yere çırparak hayatını kaybeder. Şəmistan Nəzirli’den yaptığmız “Azərbaycanın İlk Hərbi Təyyarəçisi Ferruh Ağa Gayıbov” adlı bu çeviri eser Ferruh Ağa Gayıbov’u tarihin derin sayfalarından çıkarmıştır. Abstract Ferruh Gayıbov was the first Azerbaijani combat pilot. He was the bombardier in Ilya Muromets № 16 bomber aircraft. He joined World War I. He was a relative Aliaga Şıhlinski whose name called "the God of Artillery," in the Tsarist army. Ferruh Agha was born in 2 October 1891, in the village of Salahlı Kazakh. He studied at Tbilisi Military School. When he was a first lieutenant, he attacked to the Boriana with the order of West Front Headquarter and bombed German positions and locations in September 12, 1916. Four German bomber aircraft attacked his plane. Gayıbov destroyed three of them but his plane got shot and he lost his life. Our translation of “Azərbaycanın İlk Hərbi Təyyarəçisi Ferruh Ağa Gayıbov” by Şemistan Nezirli, has revealed Ferruh Agha Gayıbov from the depths of history.

  13. SVM and ANFIS Models for precipitaton Modeling (Case Study: GonbadKavouse

    Directory of Open Access Journals (Sweden)

    N. Zabet Pishkhani

    2016-10-01

    since it is less computationally exhaustive and more transparent than other models. A consequent membership function (MF of the Sugeno model could be any arbitrary parameterized function of the crisp inputs, most like lya polynomial. Zero and first order polynomials were used as consequent MF in constant and linear Sugeno models, respectively. In addition, the defuzzification process in Sugeno fuzzy models is a simple weighted average calculation. The fuzzy space was divided via grid partitioning according to the number of antecedent MF, and each fuzzy region was covered with a fuzzy rule. Results Discussion: The statistical results showed that in first structure determination coefficient values for both the training and test was not good performance in precipitation prediction so that ANFIS and SVM had determination coefficient of 0.67 and 0.33 in training phase and 0.45 and 0.40 in test phase. Also the error RMSE values showed that both models had failed to predict precipitation in first structure. The results of second structure in precipitation prediction showed that determination coefficient of ANFIS at training and testing was 0.93 and 0.87 respectively and RMSE was 7.06 and 9.28 respectively. MBE values showed that the ANFIS underestimated at training phase and overestimated at test phase. Determination coefficient of SVM at training and testing was 0.89 and 0.91 respectively and RMSE was 9.28 and 5.59 respectively. SVM underestimated precipitation at train phase and overestimated it at test phase. ANFIS and SVM modeled precipitation using precipitation gauging stations with reasonable accuracy. Determining coefficient in the test phase was almost the same for ANFIS and SVM but the RMSE error of SVM model was about 20% lower than the ANFIS. The coefficient of determination and error values indicated SVM had greater accuracy than ANFIS. ANFIS overestimated precipitation for less than 20 mm but for higher values of uniformly distributed around the 1:1. SVM

  14. THE OCCUPATIONAL CHOICE AS A SOCIOLOGICAL PHENOMENON: QUESTIONS OF THE THEORY

    Directory of Open Access Journals (Sweden)

    A. I. Kravchenko

    2017-01-01

    alternating elections”.Sociologist is always interesting to know how a person chooses a profession: walking in the footsteps of their parents, chose institute, where was the least competition or, on the contrary, he acted in a prestigious university. If unable to pass competition from the first contest, he have done in the same institute again. Or he decided flexible approach to solving the problem, not to break the spear of an impregnable wall and choose the same profession, but in a different school. Or, in general, after the failure he has decided not to risk and spread to another profession.The occupational choice and professional orientations of young people became the subject of studies by Russian sociologists in the 1960s. Following Novosibirsk sociologists study the professional and educational orientations began Baltic sociologists headed by M.H. Titma (M.I. Talyunayte, K.A. Pyarna, Leningrad with V.V. Vodzinskoy and V.A. Yadov, sociologists from Sverdlovsk (M.N. Rutkevich, L.Ya. Rubina, F.R. Filippov, Ukrainian sociologists led by V.F. Chernovolenko (V.L. Ossovsky, V.I. Paniotto, as well asBelarussociologists (V.N. Tihonov, Ya.V. Leverovskaya,Armenia(Dzhilavyan,Tajikistan(Sh. Shoismatuloev,Uzbekistan(Z.H. Saidov,Turkmenistan(G.N. Dzhumaeva. In the 1990s and 2000s under the leadership of D.L. Konstantinovsky, V.N. Shubkin, F.E. Sheregi, V.G. Harcheva, I.M. Kozina conducted serious research professional orientations of Russian schoolchildren. The data found that the claims of the students in future career too high in comparison with the needs of society.The author seeks to draw clear boundaries between the occupational choice as a psychological (intrinsic motivation and sociological (external institutionalization phenomenon. In the second case, the person’s decision is influenced by such social agents as significant others, and social factors such as family background, material prosperity, social environment. Important factors of the occupational choice are vacancies in the

  15. Application of Bred Vectors To Data Assimilation

    Science.gov (United States)

    Corazza, M.; Kalnay, E.; Patil, Dj

    We introduced a statistic, the BV-dimension, to measure the effective local finite-time dimensionality of the atmosphere. We show that this dimension is often quite low, and suggest that this finding has important implications for data assimilation and the accuracy of weather forecasting (Patil et al, 2001). The original database for this study was the forecasts of the NCEP global ensemble forecasting system. The initial differences between the control forecast and the per- turbed forecasts are called bred vectors. The control and perturbed initial conditions valid at time t=n(t are evolved using the forecast model until time t=(n+1) (t. The differences between the perturbed and the control forecasts are scaled down to their initial amplitude, and constitute the bred vectors valid at (n+1) (t. Their growth rate is typically about 1.5/day. The bred vectors are similar by construction to leading Lya- punov vectors except that they have small but finite amplitude, and they are valid at finite times. The original NCEP ensemble data set has 5 independent bred vectors. We define a local bred vector at each grid point by choosing the 5 by 5 grid points centered at the grid point (a region of about 1100km by 1100km), and using the north-south and east- west velocity components at 500mb pressure level to form a 50 dimensional column vector. Since we have k=5 global bred vectors, we also have k local bred vectors at each grid point. We estimate the effective dimensionality of the subspace spanned by the local bred vectors by performing a singular value decomposition (EOF analysis). The k local bred vector columns form a 50xk matrix M. The singular values s(i) of M measure the extent to which the k column unit vectors making up the matrix M point in the direction of v(i). We define the bred vector dimension as BVDIM={Sum[s(i)]}^2/{Sum[s(i)]^2} For example, if 4 out of the 5 vectors lie along v, and one lies along v, the BV- dimension would be BVDIM[sqrt(4), 1, 0

  16. Physics Computing '92: Proceedings of the 4th International Conference

    Science.gov (United States)

    de Groot, Robert A.; Nadrchal, Jaroslav

    1993-04-01

    Transputer Arrays * Distribution of Ions Reflected on Rough Surfaces * The Study of Step Density Distribution During Molecular Beam Epitaxy Growth: Monte Carlo Computer Simulation * Towards a Formal Approach to the Construction of Large-scale Scientific Applications Software * Correlated Random Walk and Discrete Modelling of Propagation through Inhomogeneous Media * Teaching Plasma Physics Simulation * A Theoretical Determination of the Au-Ni Phase Diagram * Boson and Fermion Kinetics in One-dimensional Lattices * Computational Physics Course on the Technical University * Symbolic Computations in Simulation Code Development and Femtosecond-pulse Laser-plasma Interaction Studies * Computer Algebra and Integrated Computing Systems in Education of Physical Sciences * Coordinated System of Programs for Undergraduate Physics Instruction * Program Package MIRIAM and Atomic Physics of Extreme Systems * High Energy Physics Simulation on the T_Node * The Chapman-Kolmogorov Equation as Representation of Huygens' Principle and the Monolithic Self-consistent Numerical Modelling of Lasers * Authoring System for Simulation Developments * Molecular Dynamics Study of Ion Charge Effects in the Structure of Ionic Crystals * A Computational Physics Introductory Course * Computer Calculation of Substrate Temperature Field in MBE System * Multimagnetical Simulation of the Ising Model in Two and Three Dimensions * Failure of the CTRW Treatment of the Quasicoherent Excitation Transfer * Implementation of a Parallel Conjugate Gradient Method for Simulation of Elastic Light Scattering * Algorithms for Study of Thin Film Growth * Algorithms and Programs for Physics Teaching in Romanian Technical Universities * Multicanonical Simulation of 1st order Transitions: Interface Tension of the 2D 7-State Potts Model * Two Numerical Methods for the Calculation of Periodic Orbits in Hamiltonian Systems * Chaotic Behavior in a Probabilistic Cellular Automata? * Wave Optics Computing by a Networked-based Vector

  17. Kongre İzlenimleri

    Directory of Open Access Journals (Sweden)

    Yasemin Balcı

    2007-12-01

    İstanbul Üniversitesi Yard. Doç. Dr Hülya Yükseloğlu, Phd. İstanbul Üniversitesi Araştırma Gör. Şebnem Özcan İstanbul Üniversitesi Doktora Öğr. Itır Tan İstanbul Üniversitesi Prof. Dr. Ümit Biçer Kocaeli Üniversitesi Prof. Dr. Kemalettin Acar Pamukkale Üniversitesi Güney Ersoy ATUD (2 yaşındaki en küçük katılımcımız, Özlem & Gökhan çiftinin oğlu Sözlü Bildiriler 1-\tEffects of ambulance craches on transporting patient’s death. E. Özlem, E. Gökhan, AE. Ülker, K. Gülay, E. Süheyla, Y. Özlem 2-\tEvaluation of deaths after immunization. E. Gökhan, Y. Özlem, T. Sad, B. Ersin 3-\tThe importance of measuring intraocular pressure (IOP using a tonometer in order to estimate the post-mortem interval. Y. Balcı, H. Başmak, B. Kenan Kocatürk, A. Şahin, K. Özdamar 4-\tNatural childhood and adolescant deaths in medicolegal autopsy cases in Adana- Turkey. GM. Korkut, M. Demet, A. Ramazan, Ç. Nemci, H. Ahmet 5-\tSudden cardiac death and Glycoprotein iib/iia polymorphism. P. Öncü, P. Danae,, Y. Kocias, KF. Elena, E. Abacı Kalfaoğlu, M. Panagiotis, S. Atasoy, M. Emmanuel 6-\tWhat about the forensic toxicology in Adana-Tur-key. B. Dilek, GM. Korkut, D. Nebile, H. Abmet. 7-\tThe significance of the prolanged hungers in forensic medicine. N. Küçükçallı, Ü. Biçer, C. Yorulmaz, Ö. Özkalıpçı Poster Bildirileri T Intrafamilier violence cases of Pamukkale University, School of Medicine, Department of Forensic Medicine between May 2003-July 2004. B. Boz, K. Acar, A. Kurtuluş 2-\tThe use of cannines in forensics: a Turkey perspective. S. Şebnem Özcan, H. Akın, H. Bayram, M. Baş, A. Yıldız, A. Özdemiroğlu 3-\tCrime Scene investigation in Adana-Turkey-“An analyses for yesterday, today and tomorrow. MK. Gülmen, H. Kaygısız, B. Gönültaş, D. Meral, R. Akcan 4-\tAllele frequencies for 15 STR loci of Çukurova Region from Turkey: Preliminary study. C. Hüsniye, S. Ayşe, A. Behnan 5-\tFemale homicide victimization

  18. From the Editor

    Directory of Open Access Journals (Sweden)

    Ugur DEMIRAY

    2006-04-01

    activities, students learn the major points and minor points. So, in her paper, the principles that govern the development of the instructional strategies of Testing and Evaluation in English course of Distance English Language Teacher Training (DELTT Program are presented. Firstly, the program and the course are described briefly. Then the major underlying principles are presented with reference to the related literature and examples from the course are provided. Three book reviews are published in this issue which entitled as “ON-LINE EDUCATION: An Emancipating Vision”, edited by Written by Margarita Victoria Gomez and, published by Cortez Editora, São Paulo, Brazil, in July 2004. Sthe second one is “Trends and Issues in Distance Education: International Perspectives”, edited by Yusra Laila Visser, Lya Visser, Michael Simonsın, & Ray Amirault, 2005, USA, Information Age Publishing. The last and third one is entitled “Teaching With Educational Technology in the 21st Century: The Case of The Asian-Pasific Region”, edited by Yukiko Inoue & Suzanne Belland and published by Information Science Publishing in 2006. The first book “ON-LINE EDUCATION: An Emancipating Vision” is reviewed by Ricardo Romo TORRES. He is from Manuel Moreno Castaneda, Maria del Sol Orozco Aguirre, Universidad de Guadalajara Virtual, MEXICO. Reviewer Dr. Torres indicates in his review that “"On-line Education" is a book that meets the challenge to present itself as an unfinished text. In addition to demanding an active participation of the reader, it requires a predisposition to complete it through an also inconclusive dialogue. Among its goals we can find the search for education networks that remain under constant reconstruction, maintaining the emancipative vision as an imperative for the reconfiguration, as a constituted tissue for the scaffolding of subjects who impress, imagine, think and have a will”. Second book, is “Trends and Issues in Distance Education: International

  19. From Editor

    Directory of Open Access Journals (Sweden)

    Ugur Demiray

    2013-07-01

    interviews. Frequencies and percentages were used to analyze the categorical data. Moreover, the qualitative data was analyzed via content analysis. According to the findings of the study, students needed to get support about education directives, career guidance, technical equipment, and personal problems. In this issue we published two book reviews. The first issue on “UNIVERSITY TEACHING IN FOCUS:A Learning-centred Approach” which is edited by Lynne HUNT and Denise CHALMERS and reviewed by S. K. PULIST from india. He empasises about the book that The book as the name depicts, focuses on different aspects of university teaching from learner-centred point of view. A wise range of issues has been highlighted and properly addressed by the authors in a very diligent manner. It will help the teachers in constructively engaging the students in effective learning. It is a step forward towards empowering the upcoming teachers with necessary strategies and stand point so that they are able to help the students in enhancing their quality learning. The book would be helpful not only to the novice teachers who have just stepped in the teaching profession but also other stakeholders of higher education system. 2nd book review is on “TRENDS AND ISSUES IN DISTANCE EDUCATION: International Perspectives, Second Edition”, edited by Lya Visser, Yusra Visser, Ray Amirault & Michael Simonson and Reviewed by Dr. Dilek ALTUNAY from Mustafa Kemal University, Hatay, TURKEY. She mentioned about the book that this book makes a contribution to the field of distance education by offering a comprehensive overview and analysis of the current trends and issues in distance education. In addition, the book is well-organized and coherent in terms of presentation. The reader is guided by section editors who provides introduction to the section and an overview of the chapters in the section, which makes the book reader-friendly. To receive further information and to send your recommendations and