1,720,966 research outputs found
SIFAT OPTIK, STRUKTUR KRISTAL DAN STRUKTUR MIKRO LAPISAN TIPIS ZnO:Al PADA SUBSTRAT KACA SEBAGAI BAHAN TCO
Full text linkSIFAT OPTIK, STRUKTUR KRISTAL DAN STRUKTUR MIKRO LAPISAN TIPIS ZnO:Al PADA SUBSTRAT KACASEBAGAI BAHAN TCO. Telah dilakukan karakterisasi sifat optik, struktur kristal dan struktur mikro lapisan tipisZnO:Al hasil deposisi pada substrat kaca sebagai bahan Transparent Conducting Oxide (TCO) untuk sel suryadengan metode DC sputtering. Penelitian ini bertujuan untuk memperoleh hasil lapisan tipis ZnO:Al yang dapatdigunakan sebagai bahan TCO untuk sel surya. Parameter sputtering optimum diperoleh pada kondisi suhu substrat450 oC, tekanan gas 6 x 10-2 torr dan waktu deposisi 1,5 jam. Sifat optik (transmitansi) lapisan tipis ZnO dan ZnO:Almasing-masing (62 - 80) % dan (20 - 68) % pada posisi panjang gelombang (400 - 800) nm. Struktur kristal lapisantipis ZnO dan ZnO:Al terorientasi pada bidang (002) masing-masing dengan sudut hamburan 2q = 34,810o dan34,715o atau terorientasi pada arah sumbu-c yang tegak lurus pada permukaan substrat. Hasil pengamatan strukturmikro dengan SEM, menunjukkan bahwa morfologi permukaan berbentuk butiran-butiran kecil yang terdistribusi cukuphomogen dan mempunyai ketebalan sekitar 1,5 mm untuk lapisan tipis ZnO, sedangkan untuk lapisan tipis ZnO:Alketebalannya sekitar 1,0 mm
PENGARUH KONSENTRASI BORON TERHADAP SIFAT LISTRIK LAPISAN TIPIS (a-Si:H:B)
Full text linkPENGARUH KONSENTRASI BORON TERHADAP SIFAT LISTRIK LAPISAN TIPIS (a-Si:H:B). Telah dilakukan deposisibahan Si:B pada permukaan substrat kaca dengan teknik plasma sputtering DC. Deposisi dilakukan untuk beberapaparameter proses yang meliputi: waktu deposisi, tekanan gas dan suhu substrat dengan tujuan dapat diperolehlapisan tipis (a-Si:H:B) yang mempunyai konduktivitas yang memadai sebagai bahan sel surya. Target adalahbahan silikon yang telah dicampur boron dengan konsentrasi (0,1; 0,3; 0,5; 0,7) % berat. Variasi waktu deposisiadalah (0,5 - 2) jam, tekanan gas (1,1 ´ 10-1 - 1,4 ´ 10-1) Torr dan suhu substrat (150–300) oC, sedangkan gasreaktif hidrogen selama proses deposisi dibuat tetap sebesar 4 sccm. Pengukuran sifat listrik dilakukan denganprobe empat titik, konduktivitas dihitung dengan pendekatan rumus matematik. Hasil penelitian menunjukkan bahwaresistansi terkecil sebesar R = 2,73 ´ 108 W, ini diperoleh pada kondisi percobaan, waktu deposisi 1,5 jam, tekanangas 1,4 ´ 10-1 Torr dan suhu substrat 200 oC. Dengan demikian dapat disimpulkan bahwa parameter proses di atasmerupakan parameter deposisi yang optimum untuk pembuatan lapisan tipis (a-Si:H:B)
Influence of Substrate Temperature on Structural, Electrical and Optical Properties of ZnO:Al Thin Films
Full text linkTransparent and conductive aluminium-doped zinc oxide thin films have been prepared by dc magnetron sputtering technique using targets composed of ZnO and aluminium. Polycrystalline ZnO:Al films were deposited onto a heated glass substrate. Surface morphology and crystalline structure as well as optical and electrical properties of the deposited films were found to depend directly on substrate temperature. From optical and electrical analysis it was observed that optical transmittance and conductivity of the ZnO:Al transparent conductive oxide films increased when the deposition temperature was raised from 200 to 400 oC. Films grown on substrates heated at 300 oC showed a high conductivity value of 0.2 x 102 Ω-1cm-1 and a visible transmission of about 80%. The growth of ZnO:Al thin films on the surface of glass substrate at temperatures of 300 oC and aluminium doping levels of 0.9 at.% were the best to attain ZnO:Al films with optical and structural qualities as required for solar cell applications, as a window material in antireflection coatings or optical filters.Received: 17 March 2009; Revised: 22 November 2009 ; Accepted: 23 November 200
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
KARAKTERISASI SIFAT OPTIK LAPISAN TIPIS ZnO:Al PADA SUBSTRAT GELAS UNTUK JENDELA SEL SURYA
Full text linkKARAKTERISASI SIFAT OPTIK LAPISAN TIPIS ZnO:Al PADA SUBSTRAT GELAS UNTUK JENDELA SEL SURYA. Telah dilakukan karakterisasi sifat-sifat optik lapisan tipis ZnO:Al pada substrat gelas untuk jendela sel surya dengan metode sputtering. Penelitian ini bertujuan untuk memperoleh lapisan tipis ZnO:Al yang dapat digunakan sebagai bahan TCO (Transparent Conducting Oxide) untuk sel surya silikon amorf. Untuk mendapatkan lapisan tipis ZnO:Al dengan sifat optik optimum, proses deposisi dilakukan dengan beberapa variasi parameter, yaitu variasi konsentrasi campuran Al, suhu substrat, tekanan gas dan waktu deposisi. Berdasarkan hasil eksperimen yang telah dilakukan diperoleh hasil lapisan tipis ZnO:Al yang optimum pada kondisi suhu 450 oC, tekanan gas 6×10-2 torr dan lama waktu deposisi 1,5 jam. Dari pengukuran sifat-sifat optik (transmitansi) dengan UV-vis diperoleh hasil optimum pada suhu 450 oC. Pada kondisi ini transmitansinya sekitar (50-82) %, pada tekanan gas 6×10-2 torr sekitar (50-80) % dan pada waktu deposisi 1,5 jam sekitar (49-81) % yang semuanya pada posisi panjang gelombang (500-800) nm.. Untuk lapisan tipis ZnO diperoleh hasil transmitansi sekitar (78 - 80) % pada posisi panjang gelombang (500-800) nm. Hasil foto dengan SEM, untuk lapisan tipis ZnO diperoleh tebal lapisan sekitar 1,5 μm, morfologi permukaan dan butiran-butiran kecil terdistribusi secara homogen. Sedangkan untuk lapisan tipis ZnO:Al diperoleh tebal lapisan sekitar 1,3 μm dan morfologi permukaan yang terbentuk dengan butiran-butiran yang tidak seragam
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
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