1,720,964 research outputs found
Effect of catalysts and dopants on the growth mechanism of ZnO nanorods
Full text link본 논문에서는 수평형 반응관을 이용하여 ZnO 나노로드를 제작함에 있어, 성장양식을 고찰하고 촉매의 종류와 불순물이 이 성장양식에 미치는 영향에 대해 고찰하였다. 본 논문은 총 5장으로 구성되어 있으며 각 장의 내용은 다음과 같다.
제1장에서는 나노구조와 나노물질에 대한 간략한 소개와 1차원의 나노구조, 그리고 ZnO 나노로드의 성장방법에 대해 소개하였다. 제2장에서는 제작된 ZnO 나노로드의 구조적 특성을 평가하기 위해 사용된 SEM과 불순물의 함량을 평가하기 위해 사용된 EDX에 대해서 자세히 소개하였고, 종래의 나노로드 성장양식에 관한 연구들을 정리하였다. 제3장에서는 금속촉매인 AuGe과 Ti을 사용하여 성장시킨 ZnO 나노로드에서 얻어진 데이터를 통해 이론적인 곡선과 비교하여, 촉매가 성장양식에 미치는 영향에 대해 고찰하였다. 제4장에서는 In이 도핑된 ZnO 나노로드를 성장하여 불순물이 성장양식에 미치는 영향에 대해 고찰하였다. 마지막으로 제5장에서는 본 논문에서 얻어진 결과를 정리하여 결론을 기술하였다.논 문 요 약 1
Abstract 2
Figure list 3
Table list 7
Chapter 1. Introduction
1.1) Introduction to nanostructures and nanomaterials 8
1.2) Various nanostructures 11
1.3) One dimensional nanostructures 15
1.4) Synthesis methods of one-dimensional nanostructure 17
1.4.1) Spontaneous growth 17
1.4.2) Electrospinning 18
1.4.3) Lithography 19
1.5) Proposal and organization of this thesis 21
REFERENCES 25
Chapter 2. Experiment and Theoretical background
2.1) Synthesis of nanorods 29
2.2) Characterization of nanorods 30
2.2.1) Scanning Electron microscopy (SEM) 30
2.2.2) Energy dispersive X-ray spectroscopy (EDX) 33
2.3) Various growth mechanisms 36
2.3.1) Vapor-liquid-solid growth mechanism 37
2.3.2) Vapor-solid-solid growth mechanism 39
2.3.3) Solid-liquid-solid growth mechanism 41
2.3.4) Diffusion induced growth 42
REFERENCES 47
Chapter 3. Growth mechanism of ZnO nanorods on various catalyst
3.1) Introduction 50
3.2) Experimental details 52
3.3) Characterization of ZnO nanorods on various catalyst 53
3.4) The effect of catalyst on growth of ZnO nanorods 56
3.5) Conclusion 59
REFERENCES 60
Chapter 4. Growth mechanism of Impurity doped ZnO nanorods
4.1) Introduction 63
4.2) Experimental details 65
4.3) Characterization of In doped ZnO nanorods 66
4.4) The effect of dopants on growth of ZnO nanorods 69
4.5) Conclusion 70
REFERENCES 72
Chapter 5. Conclusions 75
APPENDIX _ Magnitudes of Surface Energies 78
CURRICULUM VITAE 81
ACKNOWLEDGEMENTS 8
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
Novel Hydroxyapatite Beads for the Adsorption of Radionuclides from Decommissioned Nuclear Power Plant Sites
No full textAlthough a powdered form of hydroxyapatite (p-HdA) has been studied for the adsorption of heavy metals that contaminate the restoration sites of decommissioned nuclear power plants, most of the studies are limited in the laboratory due to the head loss and post-separation in practical applications. Herein, we fabricated a porous bead form of HdA (b-HdA) as a novel adsorbent for removing radionuclides from aqueous environments via a facile synthesis by mixing the p-HdA precursor and polyvinyl butyral (PVB) as a binder and added a sintering process for the final production of a porous structure. The spherical b-HdA with an approximate diameter of 2.0 mm was successfully fabricated. The effectiveness of the b-HdA at removing Co(II) was investigated via the adsorption equilibrium at various experimental temperatures. The b-HdA exhibited the adsorption capacity for Co(II) ions with a maximum of 7.73 and 11.35 mg/g at 293 K and 313 K, respectively. The experimental kinetic data were well described using a pseudo-second-order kinetic model, and the adsorption mechanisms of Co(II) onto the b-HdA were revealed to be a chemisorption process with intraparticle diffusion being the rate-limiting step. In addition, the competitive adsorption onto the b-HdA with the order of U(VI) > Co(II) > Ni(II) > Sr(II) > Cs(I) was also observed in the multi-radionuclides system. Considering the advantages of the size, applicability to the continuous-flow column, and the easy separation from treated water, the b-HdA can be an excellent absorbent with high potential for practical applications for removing radionuclides
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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