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Caracterización de sensibilidad y degradación de películas ultra-delgadas de Al2O3 y su aplicación en sensores de estado sólido sensibles a iones
Get PDFThe development of solid state chemical sensors has been remarkable since its introduction
in the early 70s. Nowadays, a big number of parameters, and specially the
pH, can be measured with these devices at a low cost and with high accuracy. These
sensing devices can be classified in three main branches: Ion Selective Field Effect
Transistors (ISFETs), Light Addressable Potentiometric Sensors (LAPS), and capacitive
Electrolyte-Insulator-Semiconductor (EIS) sensors [1].
Generally, the operation of these devices is based upon the EIS system in which the
chemical sensitivity depends on the potential variation at the electrolyte-insulator interface,
and this variation is caused by changes in the chemical composition of the analyte
and the insulator surface [1–4]. However, the chemical degradation of the sensing surface
and the conduction mechanisms of the EIS system lead to the temporal variation of
the chemical sensitivity, commonly known as Drift, and Hysteresis [5–7]. Being these
last two phenomena, along with the problem of device encapsulation and integration of
reference electrodes, the bigger back draw in the application of these sensors [1, 2].
Taking into account the chemical sensitivity, drift and hysteresis, as well as the sensor
and reference electrode monolithic integration, this thesis presents a capacitive EIS
sensors design, the characterization of CMOS technology ISFET sensors with on-chip
pseudo-reference electrodes, and the characterization of aluminum oxide films (Al2O3)
deposited by Atomic Layer Deposition (ALD), as an alternative for sensing layers .
The designed sensors present a novel capacitive configuration which makes the change
in the flat-band voltage VFB higher, and allows the study of the influence that the area, geometry and distance of the integrated reference electrodes to the sensing regions have
in the chemical sensitivity. Moreover, the characterization of the ISFETs shows that
it is possible to integrate sensors and the required elements for their operation using
a standard CMOS processes. Finally, the influence that the chemical and morphological
degradation of the Al2O3 films surface and bulk have in sensitivity, drift and hysteresis
of the sensors is characterized.El desarrollo de los sensores químicos de estado sólido ha sido notable desde su aparición a principios de los 70s. Hoy en día un gran número de parámetros, y en especial
el pH, pueden ser medidos con estos dispositivos a un bajo costo y con alta precisión.
Estos elementos sensibles pueden catalogarse en tres ramas principales: Transistores
de Efecto de Campo Sensibles a Iones (ISFETs), Sensores Potenciométricos Direccionables
por Luz (LAPS), y Sensores Capacitivos Electrolito-Aislante-Semiconductor
(EIS) [1].
En general, la operación de estos dispositivos está basada en el sistema EIS en el
cual la sensibilidad química depende del cambio de potencial en la interfase electrolito aislante,
y este cambio se debe a su vez a la variación de la composición química del
electrolito por analizar y la superficie del aislante [1–4]. Sin embargo, la degradación
química de la superficie del aislante sensible y los mecanismos de conducción a través
del sistema EIS llevan a la variación temporal de la sensibilidad química, comúnmente
llamado deriva, y a la histéresis [5–7]. Son estos últimos dos fenómenos, en conjunto
con el problema del encapsulado de los dispositivos y la integración de electrodos de
referencia, las mayores atenuantes en la aplicación de estos sensores [1, 2].
Tomando en consideración la sensibilidad química, la deriva e histéresis, así como
la integración de sensores y electrodos de referencia en el mismo chip, esta tesis presenta
el diseño de sensores capacitivos EIS, la caracterización de sensores ISFET con
pseudo-electrodos de referencia integrados, y la caracterización de películas sensibles
de óxido de aluminio (Al2O3) obtenidas por Depósito por Capas Atómicas (ALD) , como una alternativa a los dieléctricos sensibles depositados por métodos convencionales.
Los sensores diseñados presentan una configuración capacitiva novedosa que permite
que los cambios en el voltaje de banda plana VFB sean mayores, y permitirán el estudio
de la influencia que el área, la geometría y la distancia de los electrodos integrados a
las regiones sensibles tienen en la sensibilidad electroquímica. Por otra parte, la caracterización de los ISFETs demuestra que es posible la integración de sensores y los
elementos necesarios para su operación usando un proceso CMOS estándar. Finalmente,
se caracteriza la influencia que la degradación química y morfológica de la superficie
y cuerpo de las películas de Al2O3 tienen en la sensibilidad, deriva e histéresis de los
dispositiv
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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