1,721,116 research outputs found
Polymer memristor for information storage and neuromorphic applications
No full textPolymermaterials have been considered as promising candidates for the implementation of memristor devices due to their low-cost, easy solution processability, mechanical flexibility and ductibility, tunable electronic performance through innovative molecular design cum synthesis strategy and compatibility with complementary metal oxide semiconductor (CMOS) technology as well. The digital-type polymer memristor behaves as resistive random access memory with non-volatility, high density, more speed, low power consumption, large ON/OFF ratio, high endurance and long retention, and is recognized as an appealing candidate for the next generation "universal memory". As a logic component, the analog-type memristor, with the ability to emulate the fundamental synaptic functions of short-term/long-term plasticity (STP/LTP), spike-timing dependent-plasticity (STDP), spike-rate dependent plasticity (SRDP) and "learningexperience" behaviors, can be used to construct artificial neural networks for neuromorphic computation. In this review, we shall attempt to summarize the recent progress in research on the materials, switching characteristics and mechanism aspects of two terminal polymer memristors, for both information storage and neuromorphic applications that inspire great interest in the industrial and academic communities
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
relationship between magnetic domain configuration and crystallographic orientation in a colossal magnetoresistive material
No full textWe investigated the relationship between the magnetic domain (MD) configuration and crystallographic orientation in a colossal magnetoresistive (CMR) material La0.69Ca0.31MnO3 in which anisotropic magnetoresistance (AMR) was observed as well. It was observed that the MD structure with a micrometre scale in the (001) plane collapses when a modulated structure with a nanometre scale emerges near the Curie temperature (T-c). On the other hand, twin boundaries were observed to develop in the (110) plate, and they pin the MD walls. Like the pinning effect on MD walls, the emergence of vortex-like tadpole closure MDs upon the application of external magnetic field may be an origin of the AMR in La0.69Ca0.31MnO3
Crystallization Behavior of FeSiBPCu Nanocrystalline Soft-Magnetic Alloys with High Fe Content
No full textCrystallization behaviors of Fe83.3Si4B12-xPxCu0.7 (x = 0-8) nanocrystalline alloys containing precipitated phases corresponding to the compositions and stages, crystallization kinetics, as well as the solute atom distributions after nanocrystallization were studied detailedly. The P containing alloys have higher nanocrystallization activation energy and frequency factor which is benefit to form more uniform microstructure with high density of alpha-Fe(Si) grains. During nanocrystallization, P and B are excluded to the residual amorphous phase, while Si is partitioned in the alpha-Fe(Si) phase. The formation of Fe-3(B, P) with more complex structure makes the second crystallization require longer range atom rearrangements and results in the enhanced thermal stability of the residual glassy phase against crystallization
Mg-based bulk metallic glass composite containing in situ microsized quasicrystalline particles
No full textA novel in situ forming Mg66Zn29Ca4Y1 composite comprising microsized icosahedral quasicrystal phase (I-phase) particles dispersed within a Mg-based metallic glass matrix was synthesized. The size and volume fraction of the I-phase particles are similar to 25-35 mu m and similar to 10%, respectively. The I-phase particles can noticeably improve both the strength and plasticity of the composite. The mechanism of the hard I-phase particles on the deformation and fracture behaviors of the composite and the synthesis strategy of the composite are discussed. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved
Resistance-Switchable Graphene Oxide-Polymer Nanocomposites for Molecular Electronics
No full textAs the thinnest material ever known in the universe, graphene has attracted a tremendous amount of attention in recent years. To switch graphene ON and OFF for memory devices, electroactive polymers, including polyaniline (PANI), polyvinylcarbazole (PVK), triphenylamine-based polyazomethine (TPAPAM), polythiophene (PTh), and others, have been covalently bonded to graphene oxide (GO) to manipulate the processability and to engineer the molecular bandgap of the atomic carbon nanosheets. GO-PANI, GO-PVK, and GO-TPAPAM demonstrate promising bi-stable resistive switching behaviors with small turn-on voltages of less than 2.0 V, low power consumptions of 6.7 nW-221.4 mu W, and large ON/OFF ratios exceeding 10(3). With advantages including miniaturized dimensions, mechanical flexibility, and the non-exotic nature of the raw carbon material, GO-polymer nanocomposites promise to have great potential for next-generation information-storage applications
Synthesis and nonvolatile memristive switching effect of a donor-acceptor structured oligomer
No full textAs promising nonlinear dynamic electronic devices with widespread potential applications in computer data storage and neuromorphic implementations, memristors have attracted tremendous attention in both materials science and condensed-matter physics. In this work, self-rectified memristive behavior was for the first time observed in a highly soluble metal-free all-organic material containing electron-rich fluorene and dithieno[3,2-b:2',3'-d] pyrrole moieties in the oligomer mainchain as conjugated channels for charge carriers and electron-poor 9,9-bis(3,4-bis(3,4-dicyanophenoxy) phenyl side chains in the C-9 position of the fluorene units (hereafter denoted as "PFD-8CN"). Electrical conductance of PFD-8CN can be switched between two states with a rectification ratio of similar to 10, incrementally and repeatedly. Nonlinear transmission characteristics of a biological synapse are also realized through consecutive multilevel conductance switchings. The novel electrical response of the device arises from electric fieldinduced charge transfer interactions in the donor-acceptor structured oligomer. The development of the organic memristor may offer new opportunities for the construction of molecular electronics that can greatly enhance the performance of modern computer systems
Variations on the Author
Full text link“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
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