1,721,020 research outputs found
Investigation of the optical and structural properties of the AlN layer grown with different temperetures and V/III ratio on patterned sapphire substrate
No full textFen Bilimleri Enstitüsü, Nanoteknoloji Mühendisliği Ana Bilim DalıBu tez çalışması kapsamında, III-Nitrat ailesinin en geniş bant aralığına sahip üyesi olan AlN ince filmleri farklı sıcaklık ve V/III oranları kullanılarak Sivas Cumhuriyet Üniversitesi Nanofotonik Uygulama ve Araştırma Merkezi (CÜNAM) bünyesinde kurulu olan Metal-Organik Kimyasal Buhar Biriktirme (MOCVD) sistemi ile büyütülmüştür. Büyütmelerin tümünde desenli safir alttaşlar kullanılmıştır. Büyütülen AlN ince filmlerin yapısal özellikleri ve kristal kalitesi CÜNAM bünyesinde kurulu olan Rigaku SmartLab x-ışını kırınımı (XRD) sistemi, optik özellikleri yine CÜNAM bünyesinde kurulu olan Varian Carry 5000 UV-VIS-NIR spektrofotometre sistemi kullanılarak incelenmiştir. Numunelerin yüzey morfolojileri ve büyüme modları ise DAYTAM bünyesinde kurulu olan Zeiss Taramalı Elektron Mikroskobu (SEM) kullanılarak görüntülenmiştir.Within the scope of this thesis, AlN thin films, the member with the widest band gap of the III-Nitrate family, were grown using the Metal-Organic Chemical Vapor Deposition (MOCVD) system established in Sivas Cumhuriyet University Nanophotonics Application and Research Center (CUNAM) using different temperatures and V/III ratios. Patterned sapphire substrates were used in all growths. The structural properties and crystal quality of the grown AlN thin films were investigated using the Rigaku SmartLab x-ray diffraction (XRD) system established within CÜNAM, and their optical properties were examined using the Varian Carry 5000 UV-VIS-NIR spectrophotometer system, also established within CÜNAM. The surface morphologies and growth modes of the samples were visualized using the Zeiss Scanning Electron Microscope (SEM) installed in DAYTAM
Characterization of indium rich InxGa1-xAs epitaxial layers grown on (100) InP substrate for extended wavelength swir detector application
No full textFen Bilimleri Enstitüsü, Nanoteknoloji Mühendisliği Ana Bilim Dalı, Fen Bilimleri ve Teknolojileri Bilim DalıBu tez çalışmasında, Metal Organik Buhar Fazı Epitaksi (MOVPE) tekniği kullanılarak zengin In içerikli (x>0.53) InxGa1-xAs yapıları (100) InP alttaş üzerine epitaksiyel olarak büyütülmüş ve detaylı karakterizasyonları yapılmıştır. Bu kapsamda, örgü uyumsuz InxGa1-xAs/InP yapılarının kristal kalitesi, yapılan gaz akışı çalışmaları, Si katkılama çalışması ve büyütme sıcaklığı çalışması olmak üzere, farklı optimizasyon koşulları altında araştırılmıştır. Si katkılı ve katkısız olarak büyütülen zengin In içerikli InxGa1-xAs epitaksiyel ince filmlerin yapısal karakterizasyonu yüksek çözünürlüklü X-ışını kırınımı (HR-XRD) cihazı ile, elektriksel karakterizasyonu Hall ölçümü cihazı ile ve optik karakterizasyonu Fotolüminesans (PL) ölçüm sistemi ile gerçekleştirilmiştir. Yapılan karakterizasyon çalışmaları sonucunda, zengin In içerikli InxGa1-xAs yapılarının alaşım oranının, kristal kalitesinin, elektriksel ve optik özelliklerinin tez kapsamında incelenen parametrelere bağlı olarak etkilendiği görülmüştür. Sonuç olarak, en düşük In içeriği x=0.610 dan en yüksek In içeriği x=0.675 e olmak üzere 12 adet zengin In içerikli örgü uyumsuz InxGa1-xAs/InP yapısı genişletilmiş SWIR (1.7-3 µm) dedektör yapıları için MOVPE tekniği ile başarılı bir şekilde büyütülmüştür.In this thesis, Indium-rich (x>0.53) InxGa1-xAs structures were grown on (100) InP substrate epitaxially by Metal Organic Vapor Phase Epitaxy (MOVPE) technique and were characterized in detail. In this context, the crystal quality of In-rich InxGa1-xAs /InP structures has been investigated under different optimization conditions including Si doping, gas flow, and growth temperature studies. Structural characterization, electrical characterization, and optical characterization of In-rich InxGa1-xAs epitaxial thin films with Si-doped and undoped growth were analyzed with high-resolution X-ray diffraction (HR-XRD) device, Hall measurement device, and Photoluminescence (PL) measurement system, respectively. The result of the characterization studies has been seen that the alloy ratio, crystal quality, and electrical and optical properties of indium-Rich InxGa1-xAs structures were affected depending on the parameters examined in the thesis. As a result, the 12 lattices mismatched InxGa1-xAs/InP structures, with the lowest In content from x=0.610 to the highest In content x=0.675, were successfully grown by the MOVPE technique for extended SWIR (1.7-3 µm) detector applications
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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
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