118,566 research outputs found
Numerical methods and time-dependent physical models for the design and diagnostic of pulsed-dc magnetrons
Get PDFPulsed DC operation of magnetrons is a relatively new sputtering technique that significantly improves the properties of deposited layers. The understanding and control of phenomena taking place during pulsed DC sputtering requires new time-resolved methods of investigation.
This thesis presents a comprehensive development of new methods for magnetron design and time-resolved plasma diagnostic, based on Monte Carlo simulations and timeresolved plasma physical models derived for a pulsed DC opposed target magnetron discharge with rectangular geometry.
The numerical methods have been developed and benchmarked by the author through extensive numerical experiments. A representative set of application examples is included. The time-resolved physical models for the pulse-on and pulse-off time discharge are based on the experimental data obtained by the author, which are presented as a basis for the interpretation.
The experimental data are obtained using new time-dependent diagnostic methods combining: I-V characteristics and waveforms, time and space-resolved Optical Emission Spectroscopy (OES) and time and space-resolved Ion Energy Spectra (IBS).
The following original algorithms and new time-resolved plasma diagnostic methods arc
presented:
• Algorithm and method for Monte Carlo simulation of ion transport in the magnetron discharge, based on an original non-Runge-Kutta routine developed for calculating charged particles’ trajectories in complex, position dependent, magnetic and electric fields. The Monte Carlo simulation is used for evaluating the intensity of the pre-sheath electric field through calculations of the travel time to targets of Ar ions. The time-scale for the sputtering and selfsputtering processes is also evaluated.
A new method for time-resolved plasma diagnostic in pulsed DC discharges based on time and space-resolved OES using an acousto-optic spectrometer. The described method indicates the applicability conditions for electron temperature evaluations based on timeresolved OES. the procedure and interpretation of results. Based on time and space-resolved OES evaluations of electron temperatures, a model of the physical phenomena taking place in the pulsed DC discharge during the pulse-on time is developed.
A new method for time-resolved analysis of the Ion Energy Spectra at the substrate region in pulsed DC discharges using a mass-energy analyser. Experimental results and data analysis are presented and an original physical model for plasma behaviour during the pulse-off time is developed, explaining the mechanism for the observed increase in the ion flux and energy at substrate during pulsed DC discharges. The described model explains for the first time the above effects and allows the control of the ion flux and energy at the substrate from the choice of the pulsed DC duty cycle.
The developed plasma models and time-resolved diagnostic methods are discussed for nonferromagnetic(copper) and ferromagnetic (iron) targets and the observations are correlated in order to infer a global understanding of phenomena taking place in the pulsed DC discharge and at the substrate region
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
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
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
Letter from unknown writer to Jesse L. Boyce
No full textLetter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County
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
Sarah L. Blum Author Visit - Warrior Nurse: PTSD and Healing
No full textHear Sarah L. Blum, author of Women Under Fire: Abuse in the Military, discuss her newest book, Warrior Nurse: PTSD and Healing followed by a Q&A and book signing.
Sarah L. Blum is a decorated Vietnam veteran who served as an operating room nurse during the intense fighting of 1967. In recognition of her service, she was awarded the Army Commendation Medal.
Sponsored by CWU Veterans Center and CWU Libraries.https://digitalcommons.cwu.edu/libraryevents/1252/thumbnail.jp
Lillian L. Lambert, Author, Speaker, and Entrepreneur
No full textLillian L. Lambert, Author, Speaker, and Entrepreneu
Letter to Alfred L. Shoemaker, February 10, 1948
Get PDFA handwritten letter from an unknown author addressed to Alfred L. Shoemaker, dated February 10, 1948. Within, the author discusses the Pennsylvania Dutch word for Ash Wednesday, along with traditions associated with this day.https://digitalcommons.ursinus.edu/shoemaker_documents/1118/thumbnail.jp
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Emmett L. Bennett, Jr. Offprint Collection
Get PDFThe scholarly library of Emmett L. Bennett, Jr. compiled in the course of his Editorship of the journal Nestor (founded in 1957). The collection includes scholarly publications (offprints) and manuscripts sent by prospective authors to Dr. Bennett. Includes a Finding Aid (PDF and Word) and Catalog (an Excel document for each of two record groups: offprints collected up to 1995, and offprints collected from 1995-2011). Both the Finding Aid and Catalog are provided to facilitate researchers' searches for offprints by author, title, journal, year, and subject.Classic
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