16,384 research outputs found

    Nova família de conversores CC-CC PWM não isolados utilizando células de comutação de três estados

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    Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Tecnológico. Programa de Pós-Graduação em Engenharia ElétricaEste trabalho apresenta uma nova família de conversores CC-CC PWM não isolados. Estes novos conversores são gerados utilizando a célula de comutação de três estados, que são compostas por dois interruptores controlados, dois diodos e dois indutores acoplados. As principais vantagens destes conversores, em comparação aos conversores clássicos, são: baixas perdas de condução; reduzida ondulação de corrente tanto na entrada como na saída; freqüência nos elementos reativos o dobro da freqüência de comutação de um interruptor e reduzidos peso e volume. Devido a estas características, a nova família de conversores torna-se de fundamental importância para aplicações em baixas tensões e elevadas correntes. Principalmente para potências acima de 1kW. Os conversores são analisados para dois modos de operação: o primeiro modo quando os interruptores trabalham em não-sobreposição (non-overlapping mode) (0<D<0,5) e o segundo modo quando os interruptores trabalham em sobreposição (overlapping mode) (0,5<D<1). Portanto, para conseguir estes modos de operação, os sinais de comando PWM dos interruptores estão defasados em 180o, sendo uma importante característica destes conversores. Neste trabalho, para validar o princípio de funcionamento dos novos conversores, são escolhidos entre todas as famílias geradas, os conversores boost CC-CC PWM não isolados gerados com a célula de comutação de três estados. Portanto, apresenta-se a análise teórica, a metodologia de projeto, o exemplo de projeto e os resultados experimentais. Como exemplo de aplicação, são apresentados a análise teórica, o projeto e os resultados experimentais de um protótipo, do conversor boost gerado a partir da célula B de comutação de três estados, operando como pré-regulador de tensão com elevado fator de potência e baixo valor da taxa de distorção harmônica da corrente da rede

    The construction of Karen Karnak: The multi-author-function

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    This thesis is situated within the comparatively recent developments of Web 2.0 and the emergence of interactive WikiMedia, and explores the mode of authorship within a Read/Write culture compared to that of a Read/Only tradition. The hypothesis of this study is that the role of the audience has become merged with the author, and as such, represents new functions and attributes, distinct from a more conventional concept of authorship, in which the roles of audience and author are more separate. Read/Write and participatory culture, as defined by this study, is focused on collaboration, and includes the influences of D.I.Y. culture, Open-Source practices and the production of text by multiple authors. Multi-authorship presents a re-thinking of several concepts which support the notion of the individual author, since the focus of multi-authorship is not on attribution and ownership of a finished text, but on the continued malleability of a text. Modes of multi-authorship, demonstrated in the use of the pseudonyms Alan Smithee and Karen Eliot, represent declarative authors whose names signify multiple origins, whilst concurrently indicating a distinct body of work. The function of these names form an important context to this study, since primary research involves the construction of an experimental mode of multi-authorship utilising WikiMedia technology and the interaction of thirty nine participants, who are invited to create a body of work under the collective pseudonym Karen Karnak. The data generated by this experiment is analysed using aspects of Michel Foucault's author-function to identify and determine power structures inherent in the WikiMedia context. The interplay of power structures, including concepts such as identity, ownership and the body of work, affect the resulting mode of authorship and contribute to the construction of Karen Karnak, suggesting further areas of research into the emerging multi-author

    Improving interoperability in distributed and physical union catalogues through co-ordination of cataloguing and indexing policies : report for work package B of the JISC CC-interop project

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    This report addresses section 7.2.4 (Guidelines and Strategy for Cataloguing and Indexing Standards) of the CC-interop project plan and fulfills deliverable B3 of work package B

    jDHBenelux Author Template

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    This repository contains the latest official GitHub hosted versions of the LaTeX template that authors are required to use when they finalize their contribtions to the DH Benelux Journal. The repository synchronises with the corresponding easy-to-use and well-documented Overleaf Template that provides authors with a low threshold environment for writing LaTeX – but can be used with any LaTeX compiler. About this Release: Apart from some minor changes to the .cls, v2.0 introduces a number of new files to improve open source development with git and GitHub, including a README, a CC-BY 4.0 License, and a .gitignore file. It also prepares the repository for synchronisation with Zenodo, to improve sustainability. Full Changelog: https://github.com/DHBenelux/jDHBenelux-author-template/compare/v1.1...v2.

    Scalar soliton quantization with generic moduli

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    This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credArticle funded by SCOAP3. CP is a Royal Society Research Fellow and partly supported by the U.S. Department of Energy under grants DOE-SC0010008, DOE-ARRA-SC0003883 and DOE-DE-SC0007897. ABR is supported by the Mitchell Family Foundation. We would like to thank the Mitchell Institute at Texas A&M and the NHETC at Rutgers University respectively for hospitality during the course of this work. We would also like to acknowledge the Aspen Center for Physics and NSF grant 1066293 for a stimulating research environment which led to questions addressed in this paper

    Lp-Lq estimates for transition semigroups associated to dissipative stochastic systems

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    In a separable Hilbert space, we study supercontractivity and ultracontractivity properties for a transition semigroup associated with a stochastic partial differential equation. This is done in terms of exponential integrability of Lipschitz functions and some logarithmic Sobolev-type inequalities with respect to invariant measures. The abstract characterization results concerning the improvement of summability can be applied to transition semigroups associated to stochastic reaction-diffusion equations. (c) 2025 The Author(s). Published by Elsevier Masson SAS. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

    Incorporation of a highly luminescent semiconductor quantum dot in ZrO2-SiO2 hybrid sol-gel glass film

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    In this paper we describe a method for transferring semiconductor quantum dots, produced in non-polar solvents by an organometallic approach, into sol–gel matrices. ZrO2–SiO2 hybrid sol–gel glass films have been homogeneously doped with different semiconductor quantum dots (CdSe, CdSe@CdS and CdSe@ZnS). Both the absorption and the emission properties of the semiconductor nanocrystals are only slightly affected by the incorporation into the sol–gel matrix. The doped films showed sufficiently high refractive index for the realization of planar waveguides

    Faktor odjeka geoinformatičkih CC-časopisa

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    CC journals are an abbreviation for journals included into the Current Contents (CC) bibliographic base. CC is the most popular bibliographic database in Croatia. Its popularity is due to relatively strict criteria of journal selection, coverage of all scientific fields, frequent updates, paper abstracts/summaries, author addresses, publisher names and addresses, possibility to review content of journal issues, and additional key words which facilitate searches (On line databases, Manual, http://www.online-baze.hr/ob/novosti; link on the right side of the title page).CC-časopisi je skraćeni naziv za časopise uvrštene u bibliografsku bazu Current Contents (CC). CC je u Hrvatskoj najpopularnija bibliografska baza. Razlozi njezine popularnosti relativno su visoki kriteriji odabira časopisa, pokrivenost svih područja znanosti, učestalost ažuriranja, sažetak rada, adrese autora, nazivi i adrese izdavača, mogućnost pregleda sadržaja pojedinog broja časopisa, te dodatne ključne riječi koje unapređuju pretraživanje (On line baze podataka, Priručnik, http://www.onlinebaze. hr/ob/novosti; poveznica na desnoj strani naslovne stranice)

    Open Access to Research: Changing Researcher Behavior Through University and Funder Mandates

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    The primary target of the worldwide Open Access initiative is the 2.5 million articles published every year in the planet's 25,000 peer-reviewed research journals across all scholarly and scientific fields. Without exception, every one of these articles is an author give-away, written, not for royalty income, but solely to be used, applied and built upon by other researchers. The optimal and inevitable solution for this give-away research is that it should be made freely accessible to all its would-be users online and not only to those whose institutions can afford subscription access to the journal in which it happens to be published. Yet this optimal and inevitable solution, already fully within the reach of the global research community for at least two decades now, has been taking a remarkably long time to be grasped. The problem is not particularly an instance of "eDemocracy" one way or the other; it is an instance of inaction because of widespread misconceptions (reminiscent of Zeno's Paradox). The solution is for the world's research institutions and funders to (1) extend their existing "publish or perish" mandates so as to (2) require their employees and fundees to maximize the usage and impact of the research they are employed and funded to conduct and publish by (3) depositing their final drafts in their Open Access (OA) Institutional Repositories immediately upon acceptance for publication in order to (4) make their findings freely accessible to all their potential users webwide. OA metrics can then be used to measure and reward research progress and impact; and multiple layers of links, tags, commentary and discussion can be built upon and integrated with the primary research
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