1,721,000 research outputs found
New high performance digital memory devices fabricated with DNA and DNA-mimics
No full textWe report the first digital nonvolatile memory devices fabricated with DNA and DNA-mimicking brush polymers. Salmon testes and calf thymus DNA devices, as well as DNA-mimicking brush polymer devices revealed p-type unipolar write-once-read-many-times memory behaviors with low switching-on voltage and high ON/OFF current ratio. Such permanent memory characteristics were confirmed to originate from the charge trapping and hopping nature of nucleobase moieties. Overall, this study demonstrated that DNA and DNA-mimicking polymers are good candidate materials for the production of p-type permanent memory devices with high performance, high stability and low power consumption.111sciescopu
Finely tuned digital memory modes and performances in diblock copolymer devices by well-defined lamellar structure formation and orientation control
No full textBlock copolymers of poly(2-vinyl-9-phenylcarbazole) (PVPK) and poly(2-vinylpyridine) (P2VP) or quaternized P2VP (QP2VP), including homopolymers, were synthesized by sequential living anionic polymerization and selective post-modification: PVPK-P2VP (43/57 in volume) and PVPK-QP2VP (31/69). All polymers were amorphous and soluble in common solvents. The blocks in the copolymers were found to undergo phase-separation. Nanoscale thin film morphology details were investigated by quantitative synchrotron grazing incidence X-ray scattering (GIXS) analysis. PVPK-QP2VP (31/69) self-assembled as a vertical lamellar structure in the carbon disulfide-annealed films, exhibiting p-type unipolar write-once-read-many-times (WORM) memory behavior. In comparison, PVPK-P2VP (43/57) formed a horizontal lamellar structure in chloroform-annealed films, revealing p-type unipolar dynamic random access memory (DRAM) behavior. Both the memory systems showed very high ON/OFF current ratio, 104-109, depending on the reading voltage. The switching-ON voltage, however, was lower for the PVPK-QP2VP (31/69) film (ca. 4 V) than for the PVPK-P2VP (43/57) (ca. 6 V). Overall, WORM memory and DRAM behaviors were nicely demonstrated with high performances by the development of well-defined lamellar structure in the block copolymer films and their memory modes could be easily tuned from one to another or vice versa by the orientation control of the lamellar structure. Moreover, the excellent memory performance results based on the vertical lamellar structure open up a process feature, that digital memory devices can be significantly improved in terms of their memory capacity by the fabrication of a nanoscale vertical lamellar structure using block copolymers composed of electroactive and dielectric blocks. In addition, memory origins and mechanisms in the block copolymer films were investigated.1144sciescopu
Adaptive scheduling of acceleration and gyroscope for motion artifact cancelation in photoplethysmography
Get PDFBackground and objective: Recently, various algorithms have been introduced using wrist-worn photo-plethysmography (PPG) to provide high accuracy of instantaneous heart rate (HR) estimation, including during high-intensity exercise. Most studies focus on using acceleration and/or gyroscope signals for the motion artifact (MA) reference, which attenuates or cancels out noise from the MA-corrupted PPG signals. We aim to open and pave the path to find an appropriate MA reference selection for MA cancelation in PPG.Methods: We investigated how the acceleration and gyroscope reference signals correlate with the MAs of the distorted PPG signals and derived both mathematically and experimentally an adaptive MA reference selection approach. We applied our algorithm to five state-of-the-art (SOTA) methods for the performance evaluation. In addition, we compared the four MA reference selection approaches, i.e. with acceleration signal only, with gyroscope signal only, with both signals, and using our proposed adaptive selection.Results: When applied to 47 PPG recordings acquired during intensive physical exercise from two differ-ent datasets, our proposed adaptive MA reference selection method provided higher accuracy than the other MA selection approaches for all five SOTA methods.Conclusion: Our proposed adaptive MA reference selection approach can be used in other MA cancelation methods and reduces the HR estimation error.Significance: We believe that this study helps researchers to address acceleration and gyroscope signals as accurate MA references, which eventually improves the overall performance for estimating HRs through the various algorithms developed by research groups
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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