1,720,977 research outputs found
Effects of the ion-beam bombarded SiO2 capped layer on the microstructures and magnetic properties of FePt/SiO2 bilayers
No full textIon-Beam Bombarded SiO2 Layer Effects on the Microstructure and Magnetism in FePt/SiO2 Bilayers
No full text
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
Structural and Magnetic Properties of NiFe/NixFe1-xO Bilayers
No full text本研究利用雙離子束濺鍍技術製備鎳鐵/鎳鐵氧化物雙層薄膜，探討薄膜之結構與磁性質，熱處理效應亦一並探討。
X光繞射（XRD）研究顯示：鎳鐵（Ni80Fe20）薄膜（輔助離子束氧含量0%，以下簡稱0% O2）為面心立方（f.c.c.）結構，其晶格常數為a=3.54Å。33% O2之試片由岩鹽（rock-salt）結構組成，其晶格常數為a=4.24Å。17%O2之試片由雙相之f.c.c. NiFe（a = 3.53 Å）及rock-salt NixFe1-xO（a = 4.26 Å）固溶體所組成。電子顯微鏡（TEM）分析顯示：鎳鐵及鎳鐵氧化物薄膜，其晶粒尺寸約5 nm ～ 15 nm。TEM截面試片（X-TEM）研究結果顯示：鎳鐵（~ 25 nm）/鎳鐵氧化物（~40 nm）雙層薄膜之生長模式為垂直於基材表面的柱狀結構。試片經真空熱處理後，產生如下之相變化：annealed 7%O2試片之結構主要包含Ni（a = 3.53 Å）、Fe（a = 2.90 Å）和NiO（a = 4.17 Å）等相；annealed 33%O2試片之結構由Ni（a = 3.53 Å）、NiO（a = 4.17 Å）、Fe3O4（a = 7.98 Å）和NiFe2O4（a = 8.33 Å）等相組成。經真空熱處理後之試片，產生晶粒成長，其晶粒尺寸介於20 nm ～ 85 nm之間。
震動試樣磁力計（VSM）研究結果顯示：鎳鐵薄膜室溫之磁性質為飽和磁化強度Ms = 720 emu/cm3，矯頑磁力Hc = 2 Oe。當氧含量增加至33%O2，試片轉變為反鐵磁之鎳鐵氧化物固溶體。此試片經真空熱處理後具有磁滯曲線，其Hc 300 Oe，主要由於較硬相之NiFe2O4及Fe3O4等相生成所致。
鎳鐵/鎳鐵氧化物（Ni80Fe20/as-deposited 33%O2）雙層薄膜之矯頑磁力、交換偏壓場（He）與溫度間存在一強烈的相依性。
輔助離子束電壓（End-Hall Voltage，VEH = 80 V ～ 150 V）對鎳鐵/鎳鐵氧化物雙層薄膜研究顯示：T = 150 K時，上述試片除VEH = 80 V外，試片之磁滯曲線由兩個minor loop所組成。此顯示高電壓（即高氧含量）時，鎳鐵氧化物之結構由多相構成。此外，當VEH = 120 V時，鎳鐵/鎳鐵氧化物雙層薄膜其He隨溫度降低而增加，且其值均大於零（positive exchange field）。其餘試片之He均小於零（traditional negative exchange field）。上述試片之磁電傳輸性質研究顯示：鎳鐵/鎳鐵氧化物雙層薄膜均具有異向性磁電阻（anisotropic magnetoresistance，AMR）性質。試片室溫之磁電阻值均小於4%。當VEH = 80 V時，試片在T = 77K時具有最大之磁電阻值（total MR ratio 8.04 %）。The structural and magnetic properties of polycrystalline Ni80Fe20 (~25 nm)/NixFe1-xO (~40 nm) bilayers prepared by a dual ion-beam deposition technique were studied to gain an understanding of exchange interaction between ferromagnetic (FM) and antiferromagnetic (AFM) materials. X-ray diffractometry has shown that the Ni80Fe20 top film layer has a fcc structure (a= 3.54 ) while the bottom NixFe1-xO layer has a rock-salt structure. Different films were examined with a NixFe1-xO bottom layer that was prepared with assist-beam %O2 ratios from 25% to 36% with corresponding End-Hall voltages of 80 V to 150 V. The grain sizes of these Ni80Fe20 and NixFe1-xO range from 5 nm to 15 nm, as revealed by transmission electron microscopy (TEM). The bottom oxide layers undergo complex phase transformation after annealing.
These bilayers exhibit an enhanced coercivity (~ 30 Oe) at room temperature, compared to that of a reference Ni80Fe20 single layer. A strong temperature dependence of exchange field Hex was observed in these Ni80Fe20/NixFe1-xO bilayers whose magnitude increases linearly with decreasing temperature. A double hysteresis loop was observed at T= 150 K for samples with %O2 greater than 30% O2, indicating the existence of multiple magnetic phases in the bottom NixFe1-xO layer for samples with this and higher oxygen content in the assist beam during deposition. All the samples exhibit a typical negative exchange bias as a function of temperature except the Ni80Fe20/NixFe1-xO (34%O2) bilayer, where a positive exchange field Hex~ 60 Oe was observed at T= 150 K. The appearance of positive exchange bias at low temperature is likely due to temperature dependent changes in the interfacial pinning responsible for exchange coupling that are due to a complex NixFe1-xO structure from ion-beam bombardment during film deposition.
The typical anisotropic magnetoresistance (AMR) behavior has been observed in these Ni80Fe20/NixFe1-xO bilayers. The maximum total MR ratio (~ 8.04%) was obtained at T= 77 K in the Ni80Fe20/NixFe1-xO (25%O2) bilayer.摘要................................................................................................................................I
總目錄...........................................................................................................................V
圖目錄........................................................................................................................VII
表目錄...........................................................................................................................X
第一章 緒論...............................................................................................................1
1-1 研究動機與目的.............................................................................................1
1-2 理論基礎.........................................................................................................3
1-3 材料特性.........................................................................................................5
1-4 應用.................................................................................................................6
第二章 實驗方法...................................................................................................11
2-1 實驗設計與流程...........................................................................................11
2-2 實驗材料與基材前處理...............................................................................13
2-3 雙離子束濺鍍系統.......................................................................................14
2-4 真空熱處理...................................................................................................16
2-5 分析儀器.......................................................................................................17
2-5-1 掃描式電子顯微鏡（SEM）................................................................ 17
2-5-2 X光繞射儀（XRD）..............................................................................19
2-5-3 穿透式電子顯微鏡（TEM）.................................................................21
2-5-4 原子力顯微鏡（AFM）........................................................................23
2-5-5 電子能譜化學分析儀（ESCA）............................................................25
2-5-6 震動試樣磁力計（VSM）....................................................................26
2-5-7 磁電阻量測（MR）...............................................................................28
第三章 結果與討論...............................................................................................46
3-1 鎳鐵及鎳鐵氧化物薄膜之結構與磁性質（As-deposited）..........................46
3-1-1 SEM.........................................................................................46
3-1-2 XRD..................................................................................47
3-1-3 TEM..................................................................................48
3-1-4 AFM..................................................................................50
3-1-5 VSM..................................................................................50
3-2 真空熱處理效應（Effect of heat treatment）........................................52
3-2-1 SEM.........................................................................................52
3-2-2 XRD..................................................................................52
3-2-3 TEM..................................................................................53
3-2-4 VSM..................................................................................54
3-3 鎳鐵/鎳鐵氧化物雙層薄膜之室溫及低溫磁性質（Bilayers）.................56
3-3-1 TEM..................................................................................56
3-3-2 VSM..................................................................................56
3-4 輔助離子束效應（End-Hall Voltage）...........................................................58
3-4-1 SEM.........................................................................................58
3-4-2 TEM..................................................................................58
3-4-3 AFM..................................................................................58
3-4-4 ESCA..................................................................................59
3-4-5 XRD....................................................................................60
3-4-6 VSM.................................................................................60
3-5 磁電傳輸性質...............................................................................................62
第四章 結論...........................................................................................................123
參考文獻....................................................................................................................12
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