1,720,976 research outputs found
Fabrication and characterization of a solution processed flexible thermal sensor by using chemically synthesized GO and rGO
No full text2019 Innovations in Intelligent Systems and Applications Conference, ASYU 2019; 31 October 2019 through 2 November 2019Graphene oxide (GO) was reduced by ascorbic acid which is an environmental-friendly reductant and obtained sample was named as reduced GO (rGO). Stable dispersions of GO and rGO were prepared in N,N-Dimethylformamide (DMF). Compared to GO sample, rGO was determined to have more thermal stability, smaller sheet size and lower surface energy. GO and rGO dispersions were drop-casted on aluminum (Al) coated acetate substrate and used as thermal sensor. Fabricated sensors were tested from 25 °C to 150 °C. The sensors fabricated with GO, were not stabile against driven temperature changes. However, rGO ones, presented no thermal hysteresis effect after the first heating step. This sensor (Al/rGO/Al) acted like an NTC (Negative Temperature Coefficient) thermistor. The resistance of the rGO sensor was changed between 42 k? to 25 k? depending on the test temperature range (25 °C to 150 °C). Average beta value was calculated as 519.7649 K. © 2019 IEEE
Azot doplanmış TiO2 sentezi ve fotokatalitik aktivitesinin incelenmesi
No full textAzot (N-) doplanmış TiO2 örnekleri azot kaynağı olarak alkolamin [propanolamin (PROH), etanolamin (ETOH), dietanolamin (DETOH)], alkilamin [n-propilamin (n-PRYL), dipropilamin (DPRYL), dietilamin (DETHL)] ve NH4OH kullanılarak mikrodalga ve otoklav sentez metotları altında sentezlenmişlerdir. Sentezlenen her bir TiO2 örneğinin karakterizasyonu X-ışını kırınımı yöntemi, taramalı elektron mikroskopisi, UV-VIS absorpsiyon spektroskopisi, X-ışını fotoelektron spektroskopisi, fourier dönüşümlü kızıl ötesi spektroskopisi ve BET analizi teknikleri kullanılarak yapılmıştır. Sentezlenen tüm örneklerde TiO2 örgüsü içinde azot interstisyel safsızlık olarak bulunmaktadır. Taneciklerdeki azot miktarı sentez koşullarına ve kullanılan azot kaynaklarının yapısal farklılıklarına bağlıdır. Metilen mavisinin fotokatalitik degradasyon çalışmaları Xe lamba altında gerçekleştirilmiştir. N-doplanmış TiO2 örnekleri, doplanmamış örneklere kıyasla daha yüksek fotokatalitik aktivite göstermişlerdir. Amin kaynaklarının asidik farklılıkları ve sentez koşullarındaki uyarım farklılıkları (termal ya da mikrodalga) fotokatalitik aktivite üzerinde etkilidir. Otoklav sentez koşulu altında amin kaynağı olarak n-PRYL kullanılarak sentezlenen N-doplanmış TiO2 örneği, en az azot konsantrasyonuna sahip olmasına rağmen diğer koşullardaki örneklere kıyasla daha iyi fotokatalitik aktivite göstermiştir
Synthesis and characterization of graphene oxide for photonic applications
No full textGrafen oksit (GO) sentezinde Tour yöntemi izlenmiştir. GO'nun indirgenmesi için Vitamin C (VitC) kullanılmış ve elde edilen indirgenmiş grafen oksitlere (iGO) ait yapısal, morfolojik ve elektriksel sonuçlar referans indirgen ajan olan hidrazinin kullanım durumu ile karşılaştırılmıştır. Karakterizasyon aşamalarında, X-ışını fotoelektron spektrometre, X-ışını kırınımı cihazı, Raman spektrometresi, morötesi-görünür alan spektrofotometresi, kızıl ötesi spektroskopisi, termal gravimetrik analiz cihazı, atomik kuvvet mikroskobu ve direnç ölçüm sistemi kullanılmıştır. VitC'nin kullanımı ile hazırlanan örneklerde, ulaşılan en yüksek karbon:oksijen (C:O) oranı bazik reaksiyon koşullarında 6.02, nötral koşullarda ise 5.37 ve nötral koşul için film (damlatma-kurutma) yüzey iletkenlik değeri 0.25 Mohm/sq dir. Hidrazin varlığında indirgeme için bu değerler sırasıyla, 8.35 ve 0.71 Mohm/sq şeklindedir. GO'nun, film yüzeyinde Hidrazin ile indirgenmesi sonucu optik geçirgenlik kaybolmuş ve yüzey direnci 337 ohm/sq olarak ölçülmüştür. Her iki indirgen ajan ile de elde edilen iGO türevlerinin farklı polariteye sahip çözgenlerdeki dispersiyon kararlılıkları çok düşüktür. Bu sebeple, GO yüzeyi birincil, ikincil ve alkol amin türevleri ile modifiye edilmiştir (mGO). mGO türevlerinde 7.56'lık C:O oranı yakalanmıştır. Sentezlenen mGO türevlerinde, amin grubundaki alkil zincir uzunluğunun artması ile polar aprotik çözgenlerdeki kararlılık artarken, polar protiklerde azalmıştır. Sentezlenen GO ve mGO türevlerinin poli(etilendioksitiyofen)-poli(stirensülfonat),ile kompozit filmleri hazırlanarak yüzey iletkenlik, morfolojik özellik ve optik geçirgenlik değerleri tespit edilmiştir. Kompozitlerin yüzey direnç değerleri Mohm/sq mertebesinde olup optik geçirgenlik değerleri >%90 dır.Graphene oxide (GO) was obtained by using Tour method. Reduction of obtain GO (rGO) was carried with Vitamin C (VitC), and structural, morphological and electrical results obtained were compared with hydrazine reduced samples. X-ray photoelectron spectrometry, X-ray diffraction spectrometry, Raman spectrometry, UltraViolet-visible spectrophotometry, Fourier infrared spectroscopy, thermal gravimetric analysis, atomic force microscope and surface resistivity measurement systems were used during characterization. For the samples which were prepared with the use of VitC under basic and neutral reaction conditions, the highest carbon:oxygen (C:O ) ratio was 6.02 and 5.37, respectively, and for the latter, the surface resistivity of the film prepared by dropping-drying is 0.25 Mohm/sq. These values were 8.35 ve 0.71 Mohm/sq, respectively for the hydrazine medium. The reduction of GO by hydrazine on the film surface resulted in transmittance loss and the surface resistivity of this film was 337 ohm/sq. Independent from the reduction agent, dispersion stability of rGO samples was very low. Therefore, GO samples were modified by primary, secondary and alcohol amine derivatives (mGO) and C:O ratio of 7.56 was achieved. With the increase in alkyl chain length of the reactant amine, the dispersion stability of mGOs in polar aprotic solvents was increased while a decrease was obtained in polar protic solvents. Composite films of the synthesized rGO and mGO derivatives with poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate were prepared. The surface resistivity values of these composites were in the order of Mohm/sq and optical transmittance of > 90% was obtained in all of the films
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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