1,673 research outputs found
Conversores CC-CC básicos não-isolados quadráticos de três níveis
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia Elétrica.Este trabalho introduz uma nova célula de comutação formada por dois diodos, dois interruptores comandados, dois indutores e um capacitor. Conectada adequadamente aos terminais de uma fonte de tensão (entrada) e de uma carga, as três principais topologias dos conversores CC-CC básicos não-isolados são concebidas: buck, boost e buck-boost. A célula de comutação proposta, juntamente com uma modulação apropriada dos dois interruptores, atribui aos conversores duas características muito importantes: em nenhum instante a tensão sobre cada interruptor atinge o maior valor envolvido na conversão (entrada no buck e saída no boost) ou a soma das tensões de entrada e saída (buck-boost), e o ganho estático varia com o quadrado da razão cíclica, tornando-os atrativos em ganhos altos, especialmente o conversor boost. Além disso, o fato de haver dois interruptores acrescenta aos conversores um grau de liberdade a mais em relação às topologias convencionais, representado pelo parâmetro a. Para cada conversor foi realizada uma análise teórica detalhada, incluindo etapas de operação, ganho estático ideal, principais formas de onda, ondulação de corrente nos indutores e de tensão nos capacitores, bem como a característica externa, matemática e graficamente. Os três conversores foram montados e as principais formas de onda adquiridas a fim de validar a teoria apresentada
C.S. Lewis: Reactions from Women
No full textRecounts the experiences of eight women (including the author) who knew C.S. Lewis
C.S. Lewis’s theory of Sehnsucht as a tool for theorizing L.M. Montgomery’s experience of ‘The Flash'
No full textHigh-k fluoropolymers dielectrics for low-bias ambipolar organic light emitting transistors (Olets)
No full textFunding Information: Author Contributions: Conceptualization, A.A. and C.S.; methodology, A.A. and C.S.; validation, A.A., K.G.-R., and C.S.; data curation, A.A., K.G.-R., and C.S.; writing—original draft preparation, A.A. and C.S.; writing—review and editing, A.A., K.G.-R., and C.S.; supervision, C.S.; project administration, C.S.; funding acquisition, C.S. All authors have read and agreed to the published ver-sion ofFunding:the manuThescript.authors acknowledge the support from the Academy of Finland Flagship Program (Grant No.: 320167, PREIN) and the Aalto seed funding scheme. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Organic light emitting transistors (OLETs) combine, in the same device, the function of an electrical switch with the capability of generating light under appropriate bias conditions. In this work, we demonstrate how engineering the dielectric layer based on high-k polyvinylidene fluoride (PVDF)-based polymers can lead to a drastic reduction of device driving voltages and the improvement of its optoelectronic properties. We first investigated the morphology and the dielectric response of these polymer dielectrics in terms of polymer (P(VDF-TrFE) and P(VDF-TrFE-CFE)) and solvent content (cyclopentanone, methylethylketone). Implementing these high-k PVDF-based dielectrics enabled low-bias ambipolar organic light emitting transistors, with reduced threshold voltages (<20 V) and enhanced light output (compared to conventional polymer reference), along with an overall improvement of the device efficiency. Further, we preliminary transferred these fluorinated high-k dielectric films onto a plastic substrate to enable flexible light emitting transistors. These findings hold potential for broader exploitation of the OLET platform, where the device can now be driven by commercially available electronics, thus enabling flexible low-bias organic electronic devices.Peer reviewe
C.S. Lewis: adaptations of life and work
No full textThe author discusses film representations of the life of C.S. Lewis – a famous English Christian writer. She also focuses on adaptations (that include books, television and cinema) of his most famous series The Chronicles of Narnia – series that for already sixty years have been published all over the world
The Nurse of Elfland: Lizzie Endicott and C.S. Lewis
No full textIn Surprised by Joy, C.S. Lewis introduced Lizzie Endicott as the first of two other blessings in his childhood, even before his introduction of Warnie. But apart from his abbreviated 136-word biography, very little is known about the nurse who introduced Lewis to faery tales. Based on the Lewis Family Papers, genealogical research, and personal interviews with Lizzie’s relatives, this article introduces Lizzie to the world of Lewismania. It also suggests various ways in which Lizzie influenced the man and the author that C.S. Lewis became, as well as the mythical worlds he created and Lewis’s anonymous tributes to her
Remembering C.S. Lewis recollections of those who knew him
No full textIn this intimate, candid, and sometimes surprising community biography of the celebrated author and Christian apologist, twenty-four men and women who knew C.S. Lewis, as teacher, colleague, friend, offer their reminiscences and impressions of the complex man behind the critical and academic acclaim
C.S. Lewis as Transformational Leader
No full textThe term leadership usually evokes images of great warriors, politicians, or social figures that saturate the pages of a history textbook. However, these are pre-conceived notions of the term. Leaders are those who exercise influence, be they soldiers, politicians, or even artists such as writers and musicians. One such leader is author and apologist C.S. Lewis. Lewis spoke to his generation (and many subsequent ones) in his texts. Through Lewis, many have achieved a greater understanding of literature, spirituality, and human nature. His words have, in essence, transformed the minds of readers.
Transformational leadership is desired because it performs what is implied in its title: it transforms others. Transformational leaders increase both motivation and morality in their followers. They lead with conviction, ultimately empowering followers to become leaders. Bass (1985) posits that transformational leaders exhibit four qualities: idealized influence, inspirational motivation, intellectual stimulation, and individualized consideration.
Upon exploring transformational leadership theory, it is evident that C.S. Lewis exhibits all four qualities of a transformational leader. Lewis has led many from the desert of spiritual ambiguity into a better understanding of God and of ourselves. His words still resonate in culture and demonstrate the lasting influence of his legacy
Old Poet Remembered: The Case for the Poetry of C.S. Lewis
No full textThough well known for his fiction and essays, C.S. Lewis also wrote in poetry. Often forgotten or considered less than his prose, his poems are rich with meaning and pleasure. The author offers some perspectives on how those who love Lewis’s prose might learn to love his poetry as well.
Presented at the 1997 Frances White Ewbank Colloquium
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