161,749 research outputs found
Magnetic-Field-Induced Suppression of Jahn-Teller Phonon Bands in (La0.6Pr0.4)0.7Ca0.3MnO3: the Mechanism of Colossal Magnetoresistance shown by Raman Spectroscopy
No full textA long-standing issue in the physics of the colossal magnetoresistance is the role of electron-phonon coupling, which manifests itself as Jahn-Teller polarons. The origin and architecture of polarons makes it possible to study their behavior by Raman spectroscopy, which allows to analyze the polaronic behavior in an applied magnetic field. We performed magnetic-field-dependent Raman spectroscopy on thin films of (La0.6Pr0.4)0.7Ca0.3MnO3 in a range of H = 0-50 kOe and compared the obtained Raman spectra with the magnetic field behavior of the electrical resistivity. In the vicinity of the Curie temperature, TC = 197 K, the intensity of the Jahn-Teller stretching mode at 614 cm-1 and of the bending mode at 443 cm-1 was found to be suppressed and enhanced, respectively. This observed behavior has a remarkable similarity with the field and temperature dependence of the colossal magnetoresistance in (La0.6Pr0.4)0.7Ca0.3MnO3. Our work provides direct evidence that the reduction of the amount of Jahn-Teller polarons at the phase transition is the main mechanism underlying the colossal magnetoresistance
Interface-controlled magnetism and transport of ultrathin manganite films
No full textWe report ferromagnetic, T-C = 240 K, and metallic, T-MI = 250 K, behaviors of a three unit cell thick interface engineered lanthanum manganite film, grown by metalorganic aerosol deposition technique on SrTiO3(100) substrates. Atomically resolved electron microscopy and chemical analysis show that ultrathin manganite films start to grow with La-O layer on a strongly Mn/Ti-intermixed interface, engineered by an additional deposition of 2 u.c. of Sr-Mn-O. Such interface engineering results in a hole-doped manganite layer and stabilizes ferromagnetism and metallic conductivity down to the thickness of d = 3 u.c. The films with d = 8 u.c. demonstrate a bulk-like transport behavior with T-MI similar to T-C = 310 - 330 K. (C) 2013 American Institute of Physics
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Automated software vulnerability testing using in-depth training methods
No full textThe article provides a view on modern technologies, which are used for automatic software vulnerability testing in critically important systems. Features of fuzzing realization (which is based on making many inputs with different mutated data) are also studied. As a result, testing algorithm picks input data that is more likely to cause a fail or incorrect work of software product. Deep learning algorithms are used to decrease the computational complexity of testing process. The use of simple fuzzer and Deep Reinforcement Learning algorithm shows that the amount of mutations necessary to find vulnerabilities decreases by 30%
Automated software vulnerability testing using in-depth training methods
No full textThe article provides a view on modern technologies, which are used for automatic software vulnerability testing in critically important systems. Features of fuzzing realization (which is based on making many inputs with different mutated data) are also studied. As a result, testing algorithm picks input data that is more likely to cause a fail or incorrect work of software product. Deep learning algorithms are used to decrease the computational complexity of testing process. The use of simple fuzzer and Deep Reinforcement Learning algorithm shows that the amount of mutations necessary to find vulnerabilities decreases by 30%
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Larry O. Spencer, Conference Author Presentation
No full textGen. Larry O. Spencer, USAF (Ret.), author of Dark Horse: A Journey from the Horseshoe to the Pentago
Ruddlesden-Popper interface in correlated manganite heterostructures induces magnetic decoupling and dead layer reduction
No full textWe report on the interface engineering in correlated manganite heterostructures by octahedral decoupling using embedded stacks of atomic layers that form the Ruddlesden-Popper structure. A room temperature magnetic decoupling was achieved through deposition of a (SrO)(2)-TiO2-(SrO)(2) sequence of atomic layers at the interface between La0.7Sr0.3MnO3 and La0.7Sr0.3Mn0.9Ru0.1O3 films. Moreover, the narrowing of the interfacial dead layer in ultrathin La0.7Sr0.3MnO3 films was demonstrated by insertion of a single (SrO)(2) rock-salt layer at the interface with the SrTiO3(100) substrate. The obtained results are discussed based on the symmetry breaking and disconnection of the MnO6 octahedra network at the interface that may lead to the improved performance of all-oxide magnetic tunnel junctions. We suggest that octahedral decoupling realized by formation of Ruddlesden-Popper interfaces is an effective structural mechanism to control functionalities of correlated perovskite heterostructures. Published by AIP Publishing.Deutsche Forschungsgemeinschaft (DFG) [SFB 1073
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
The decentralized voting model using the hyperledger platform paper
No full textIt is presented theoretical statements about decentralized systems technology, blockchain networks, their structure as well as main functioning principles, structure and material about Hyperledger platform. It is examined Hyperledger services architecture, spheres of use and such important aspects as smart-contracts and their application, as well as advantages of using this platform. It is also modelled and explained the algorithm and schematic diagram of voting network built with Hyperledger platform
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