1,720,961 research outputs found
Polymer photochemistry at the EUV wavelength
No full textThe higher energy associated with extreme ultraviolet (EUV) radiation coupled with the high absorptivity of most organic polymers at these wavelengths should lead to increased excited state population and higher quantum yields of photoproducts. Polymers representative of those commonly employed in resists as well as some model polymers were selected for this study. Polymer photochemistry at EUV was catalogued as to the effect of absorbed 13.4-nm radiation on a polymer's quantum yield of chain scission (Φs) and crosslinking (Φx). In selected cases, the chain scission and crosslinking quantum yields were also compared to those previously determined at 157-, 193- and 248-nm. It was found that quantum yield values were over a magnitude greater at EUV relative to optical wavelengths.Intel Corporatio
Lithographically directed materials assembly
No full textWe have developed a processing method that significantly reduces the number of steps necessary to yield a surface that directs block copolymer assembly. This methodology employs a single resistless lithography step that directly changes the surface energy without requiring subsequent material deposition or plasma etching steps. The lithographically defined difference in surface energies acts as a template to direct diblock polymer self-assembly into low-defect periodic structures. Our newly developed lithographically directed self-assembly technique can produce sub-45 nm half pitch lines employing poly(styrene-b-methyl methacrylate) (PS-b-PMMA) and interference lithography. Once assembled into periodic lines of alternating materials, the PMMA block can be removed and the resulting polystyrene features can be used as an etch mask to transfer periodic lines-and-spaces into a silicon substrate.Defense Advanced Research Projects Agency (Air Force Contract FA8721-05-C-0002
Electron-beam Directed Materials Assembly
No full textWe have developed a processing method that employs direct surface imaging of a surface-modified silicon wafer to define a chemical nanopattern that directs material assembly, eliminating most of the traditional processing steps. Defining areas of high and low surface energy by selective alkylsiloxane removal that match the polymer period length leads to defect-free grating structures of poly(styrene-block-methyl methacrylate) (PS-b-PMMA). We have performed initial studies to extend this concept to other wavelengths beyond 157 nm. In this present paper, we will show that electron beam lithography can also be used to define chemical nanopatterns to direct the assembly of PS-b-PMMA films. Half-pitch patterns resulted in the directed assembly of PS-b-PMMA films. Electron beam lithography can also be used to prepare surfaces for pitch division. Instead of the deposition of an HSQ pinning structure as is currently done, we will show that by writing an asymmetric pattern, we can fill in the space with smaller lamellar period block copolymers to shrink the overall pitch and allow for 15-nm features.United States. Defense Advanced Research Projects AgencyUnited States. Air Force (Contract FA8721-05-C- 0002
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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