1,720,963 research outputs found
Lead-Free, Air-Stable Hybrid Organic-Inorganic Perovskite Resistive Switching and Multilevel Data Storage
No full textOrganolead halide perovskites exhibit excellent optoelectronic and photovoltaic properties such as a wide range of light absorption and tunable band gaps. However, the presence of toxic elements and chemical instability under an ambient atmosphere hindered lead halide perovskites from real device applications because of environmental issues and stability. Here, we demonstrate a resistive switching memory device based on a lead-free bismuth halide perovskite (CH3NH3)3Bi2I9 (MABI). The active layer of the device can be easily prepared by solvent engineering. The nonvolatile memory based on MABI layers has reliable retention properties (∼104 s), endurance (300 cycles), and switching speed (100 ns), as well as environmental stability. Moreover, the control of the compliance current leads to multilevel data storage with four resistance states, which can be applied to high-density memory devices. These results suggest that MABI has potential applications in information storage.114sciescopu
Mixed halide perovskite resistive switching memory: controlling operating parameters through halide incorporation
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Control of Gold Nanoparticle-Protein Aggregates in Albumen Matrix for Configurable Switching Devices
No full textProtein-nanoparticle (P-NP) interactions are of great importance in the biomedical applications, and are extensively studied for biotechnology and biomedicine applications, for example, cancer therapy, drug delivery, as well as biosafety area. Here, it is shown that P-NP interactions can have applications as resistive memory. It is demonstrated that the nature of resistive switching changes from programmable memory to read-only memory when the NPs aggregate in the protein. The memory properties can be tuned by just changing the degree of agglomeration in P-NP solutions, so it has great potential to be used in configurable memory devices. This type of memory is also biocompatible, because it uses natural protein.11sciescopu
Impact of Grain Sizes on Programmable Memory Characteristics in Two-Dimensional Organic-Inorganic Hybrid Perovskite Memory
No full textRecently, organic-inorganic hybrid perovskites (OIHPs) have been used in resistive switching memory applications because of current-voltage hysteresis that originated from ion migration in the perovskite film. As the density of the memory devices continues to increase, the size of the devices approaches that of the individual grains of the polycrystalline films. Thus, the effects of the grain boundary and the grain size will become important to investigate the influence on the switching behaviors. Here, we report the effects of grain sizes on the resistive switching property of (C4H9NH3)(2)PbBr4 (BA(2)PbBr(4)) films. The BA(2)PbBr(4) films were formed by using sequential vapor deposition. First, a lead bromide (PbBr2) film was deposited by thermal evaporation, and then the film was exposed to organic vapor to form BA(2)PbBr(4) films. The grain sizes were controlled by changing the transformation temperatures (T-T = 100, 150, and 200 degrees C). When the TT values were 100, 150, and 200 degrees C, the grain sizes of BA(2)PbBr(4) were similar to 180 nm, similar to 1, and similar to 30 mu m, respectively. In the memory device based on BA(2)PbBr(4), the off current decreased from similar to 10(-4) to similar to 10(-8) A as the grain size increased from similar to 180 nm to similar to 30 mu m. This method to synthesize BA(2)PbBr(4) films provides a simple way to control the grain sizes, and understanding of the effects of grain sizes on memory characteristics will provide an insight to improve the reliability of the OIHP-based memory as the electronic devices are scaled down to the sizes of grains.11Nsciescopu
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
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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