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Asymmetric Effect of DistributionIntensity on Marketing Performance: The Moderating Role of Brand Awareness
No full textOptical Studies on Pre-strained InGaN/GaN Quantum Wells
No full text在本研究中，我們有系統的研究不同量子井結構和厚度的氮化銦鎵/氮化鎵多重量子井光學特性及材料微結構，其中兩片樣品我們在成長五層高銦量子井之前多成長一層低銦量子井，而這五層高銦量子井的條件和控制組樣品相同，第三片樣品則是再增加量子井的厚度。從光激發螢光量測中觀察到，在底層多加入放紫光的低銦量子井的樣品中，會使得原本放綠光的量子井，頻譜紅移到橘紅光的範圍。從電激發螢光頻譜中可以看到靠近底層紫光量子井所受到的影響最大而放出橘光。應變分析結果顯示，靠近底層低銦量子井的高銦量子井，所含銦的平均含量比控制組樣品更高。銦含量增加的原因是由於低銦量子井對上層的位障層造成拉伸應變，而對接下來成長高銦量子井有更好的晶格匹配。這種效應會隨著成長更多的量子井而減小，而且對於高銦量子井，由於會有銦聚集來釋放應力，所以這種效應在高銦量子井之間並不明顯。In this research, we systematically study the optical characteristics and associated nanostructures of three InGaN/GaN multiple quantum-well (QW) samples of different QW structures. In two of the samples, a low-indium InGaN/GaN QW is grown before five high-indium ones, which are grown under the same conditions as those for growing the five QW s in another sample (the control sample). Photoluminescence (PL) measurement shows that the spectral red-shift of the QWs designated for green emission into the orange range in a light-emitting diode by adding a violet-emitting QW at the bottom. The cathodo-luminescence (CL) spectra indicate that the long-wavelength QWs close to the violet one were strongly influenced by this added QW and mainly emit the orange photons. From the calibrations of the average indium contents of those QWs based on the strain state analysis images, it is found that the QWs close to the low-indium one have higher indium contents than those in the control sample. Such an increase of indium incorporation is attributed to the pre-strain effect of the low-indium QW on the barrier layer right above it. The pre-strain effect diminishes along the growth of more QWs and is weak between the high-indium QWs, in which the formation of indium-rich clusters releases the strain.Chapter 1 Introduction…………………………………….……1
1.1 Applications of Nitride-Based Materials……………….……….……1
1.2 Growth of InGaN and InGaN/GaN Heterostructures………….….….2
1.3 Review on the Characteristics of InGaN/GaN Structures……...….…4
1.3.1 Strain Effect……………………………….………………...….4
1.3.2 Polarization and Strain-induced Piezoelectric Field….……......5
1.3.3 Spinodal Decomposition and Phase Separation……………......7
1.3.4 Indium Aggregation and Quantum Dot-like Structure…………9
1.3.5 Spontaneous Emission…………………………………….…..11
1.3.6 Band-tail Model and Temperature Dependence of Band Gap...13
1.4 Post-Growth Thermal Annealing…………………………………....15
1.5 Dependence of Optical Property On Quantum Well Width in InGaN/GaN Quantum Well Structures………………………….....17
1.6 Research Motivations and Topics………………………………...…20
Chapter 2 Sample Descriptions…………………………….…37
2.1 Sample Structures and Growth Conditions…………………………37
2.2 High-Resolution Transmission Electron Microscopy (HRTEM) …..38
2.3 X-ray Diffraction (XRD) …………………………………………...41
2.4 Electro-Luminescence (EL) ………………………………………...41
2.5 Cathodo-Luminescence (CL) ……………………………………....43
2.6 Discussions and Summary…………………………………………..44
Chapter 3 Photoluminescence (PL)………………………..…61
3.1 PL Experimental Setup…………………………………………...…61
3.2 PL Measurements Results………………………………………...…62
3.3 Discussions and Summary……………………………………….…65
Chapter 4 Time-Resolved Photoluminescence (TRPL)…….…77
4.1 TRPL Experimental Setup…………………………………………..77
4.2 TRPL Measurements Results ……………………...…………….…78
4.3 Discussions and Summary………………………….……….………82
Chapter 5 Conclusions………………………………....…….10
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
A study on the compression of compressible soft particles and filtration of its slurries
No full text本研究的主要宗旨，在於探討體積可變之可壓縮軟粒子受機械壓壓縮下之特性，以及此類物質在流體流動系統當中之流力行為。因此，本研究首先以單顆及二維平面上規則排列之多顆不可壓縮及可壓縮軟粒子，進行機械壓縮實驗，並推導出描述圓形軟粒子變形行為的圓球及橢圓壓縮模式，以分析單一軟粒子受壓後之型態；此外也將模式延伸至推估軟粒子於二維平面排列下，受壓時粒子間的孔隙度變化。實驗及分析結果顯示所推導之壓縮模式，可合理地描述軟粒子受壓下型態相關物理量(體積，表面積)之改變，並經比較而知不可壓縮軟粒子因受壓下具較大擴張量，而與可壓縮軟粒子之行為有所差異。
其次，為探討含可壓縮軟粒子之流體流動系統的行為，本研究採恆床壓力降及恆率操作方式，對可壓縮Ca-alginate粒子堆積床進行流力實驗，並以考量粒子體積可變而修正Ergun方程式，使其適於計算流體流經可壓縮軟粒子床之壓力降；同時，以此式為基礎，建立一套動態分析方法，運用於計算操作過程中堆積床之結構變化及水力行為。實驗結果顯示，恆壓力降操作下的床高有回彈之現象，與恆率操作下床高不斷下降的行為迥異；而由動態分析之結果可瞭解，若不考量粒子體積可變的影響，則在估算可壓縮軟粒子堆積床之床高變化上，將與實驗值間有相當大的偏差。
本研究第三部份，為探討含可壓縮軟粒子泥漿在恆壓及恆率操作下之過濾行為，同時針對童(1998)及Lu et al.(2001b)所提出之可變形軟粒子過濾行為之動態解析方法加以修正，針對其中的黏彈性模式，則引入粒子體積可變之概念，以對含可壓縮軟粒子泥漿之過濾行為加以解析。實驗結果顯示由於粒子在操作過程當中持續的壓縮行為，在恆壓及恆率過濾實驗曲線上，皆顯示了斜率不同的轉折，而反映出不同階段時粒子壓縮率過濾行為的影響。其次經由動態分析之結果，可瞭解雖不同過濾操作方式對於濾餅局部性質分佈有不同形式的影響，但亦可發現在同一系統壓力下，恆壓及恆壓操作所得之局部孔隙度與固體壓縮壓力之關係有相當一致的分佈。此外，以動態模擬所得之濾性值，反證恆壓過濾實驗之過濾曲線，結果顯示在過濾曲線尚未陡升前有合理的計算結果，但在轉折上升後的行為，則仍須有更進一步理論的探討。The performance of the filtration of the compressible soft particle slurries is systematically studied in the following three aspects:
First of all, the uni-axial compression of a single compressible(volume variable) or incompressible(volume invariable) soft particle without or with surrounded by other particles are studied to obtain the compression models for characterizing the properties of the soft particles in a deformation course. It is shown that the incompressible soft particle expands more significantly during compression and therefore interacts with the surrounding ones more effectively than the compressible soft particle. The results calculated by the models can properly describe the compression behaviors of the soft particles as well.
Secondly, a method of dynamic analysis based on modified Ergun equation, which considering about the volume variation of the particles, was proposed to evaluate the structural and hydro-dynamic behaviors of the compressible soft particles bed under a constant pressure-drop or a constant rate operation. Experimental results show different mechanisms for bed-height variation of the constant pressure-drop and constant rate operations. The results of dynamic analysis indicate that without considering the volume variation of the particles, reasonable estimations of the properties of the compressible particle beds are not possible.
In the third portion, compressible Sephadex and Ca-alginate particles are adopted for the cake filtration experiments under a constant pressure(CPF) and a constant rate(CRF) operation. The method of dynamic analysis of cake filtration proposed by Lu et al.(2001b) is modified by the consideration of the volume variation of the particles to investigate the local cake properties of compressible soft particles. From the experimental results, the filtration curve shows various stages due to the deformability of compressible particles. Results obtained by dynamic analysis show that although the cake structures obtained by CPF and CRF differ obviously, the relations between the local porosity and the solid compressive pressure of the two operations are approximately the same. The verification of the cake characteristic values obtained by dynamic analysis by the estimation of the CPF filtration curve agrees with the experimental value as the curves remain linear. More factors must be considered for evaluating the compression behavior of the cakes of compressible soft particles.可壓縮軟粒子之壓縮及過濾行為之研究
A STUDY ON THE COMPRESSION OF COMPRESSIBLE SOFT PARTICLES AND FILTRATION OF ITS SLURRIES
目錄
頁次
誌謝 ------------------------------------------------ I
中文摘要 --------------------------------------------- III
英文摘要 --------------------------------------------- V
目錄 ------------------------------------------------- VII
圖目錄 ----------------------------------------------- X
表目錄 ----------------------------------------------- XXI
第一章 緒論 ----------------------------------------- 1
1-1 可變形軟粒子與固液分離 ------------- 1
1-2 論文架構 --------------------------- 4
第二章 文獻回顧 ------------------------------------ 6
2-1 濾餅結構變化行為的定義 ------------ 7
2-2 粒子壓縮行為之研究 ----------------- 10
2-2-1 粒子受力作用下之行為模式 ----------- 11
2-2-2 不可壓縮軟粒子 --------------------- 12
2-2-3 可壓縮軟粒子 ----------------------- 15
2-3 流體流經堆積床及多孔體之研究 ------- 18
2-3-1 剛性粒子堆積床及剛性多孔介質 ------- 18
2-3-2 可變形軟粒子堆積床及可變形多孔介質 23
2-4 濾餅過濾之研究 --------------------- 27
2-4-1 濾餅過濾理論 ----------------------- 27
2-4-2 可壓縮及軟粒子濾餅之過濾 ----------- 32
2-4-3 濾餅成長及局部性質之動態解析 ------- 38
第三章 軟粒子機械壓縮模式 -------------------------- 42
3-1 粒子壓縮變形模式之相關研究 --------- 42
3-1-1 Hertz定律 -------------------------- 42
3-1-2 Tatara理論 ------------------------- 44
3-1-3 Lu et al.之推導 -------------------- 46
3-1-4 黏彈性模式 ------------------------- 46
3-2 可壓縮軟粒子變形行為之理論模式 ----- 48
3-2-1 側邊曲面為圓弧型態 ----------------- 49
3-2-2 側邊曲面為橢圓弧型態 --------------- 53
3-3 實驗裝置、物料及方法 --------------- 57
3-3-1 粒子壓縮實驗裝置 ------------------- 57
3-3-2 實驗物料 --------------------------- 60
3-3-3 實驗方法 --------------------------- 61
3-4 實驗及分析結果與討論 --------------- 63
3-4-1 單一軟粒子壓縮模式之探討 ----------- 63
3-4-1-1 單一軟粒子壓縮行為之觀察 ----------- 63
3-4-1-2 單一軟粒子之壓縮行為 --------------- 65
3-4-2 二維堆積軟粒子群之壓縮行為 --------- 82
3-4-2-1 相連雙球之壓縮行為 ----------------- 82
3-4-2-2 規則排列之多粒子系統壓縮行為 ------- 86
3-5 結論 ------------------------------- 96
第四章 流體流經可壓縮軟粒子堆積床之研究 ------------ 98
4-1 剛性與軟粒子堆積床特性之比較 ------- 99
4-1-1 點接觸與面接觸模式 ----------------- 99
4-1-2 粒子床高變化與時間關係 ------------- 102
4-2 流體流經粒子堆積床之水力行為－壓力降與
流量關係 --------- 103
4-2-1 孔隙度隨時間變化之關係 ------------- 105
4-2-2 球形度與孔隙度之關係式 ------------- 106
4-3 實驗裝置、物料及方法 --------------- 108
4-3-1 實驗內容 --------------------------- 108
4-3-2 實驗裝置 --------------------------- 108
4-3-3 實驗物料 --------------------------- 110
4-3-4 實驗方法 --------------------------- 112
4-4 實驗結果 --------------------------- 116
4-4-1 實驗過程之實際型態觀察 ------------- 116
4-4-2 實驗數據分析 ----------------------- 122
4-5 流體流經可壓縮軟粒子堆積床行為之動態
分析 -- 129
4-5-1 分析方法 --------------------------- 129
4-5-2 以動態分析方法模擬之結果 ----------- 134
4-6 結論 ------------------------------- 150
第五章 可壓縮軟粒子之過濾行為及其動態分析 ---------- 152
5-1 軟粒子之過濾行為 ------------------- 152
5-2 含可壓縮粒子濾餅性質之動態解析 ----- 153
5-2-1 理論背景 --------------------------- 153
5-2-2 動態模擬所需數據及模擬程序 ----------163
5-3 實驗裝置、物料及方法 --------------- 167
5-3-1 過濾實驗裝置 ----------------------- 167
5-3-2 實驗物料 --------------------------- 170
5-3-3 實驗方法 --------------------------- 172
5-4 實驗及分析結果與討論 --------------- 175
5-4-1 恆壓過濾 --------------------------- 175
5-4-1-1 實驗結果 --------------------------- 175
5-4-1-2 恆壓過濾實驗之動態分析結果 --------- 181
5-4-2 恆率過濾 --------------------------- 189
5-4-2-1 實驗結果 --------------------------- 190
5-4-2-2 恆率過濾實驗之動態分析結果 ----- 193
5-4-3 恆壓與恆率過濾操作下之濾餅性質比較 199
5-4-4 以動態模擬所得濾性值預測過濾行為 --- 203
5-5 結論 ------------------------------- 208
第六章 總結 ---------------------------------------- 210
符號說明 --------------------------------------------- 212
參考文獻 --------------------------------------------- 217
中英對照 --------------------------------------------- 229
附錄 ------------------------------------------------- 232
A. 實驗用物料特性 --------------------- 232
B. 實驗設備細目及校正曲線 ------------- 240
C. 單一軟粒子壓縮模式之詳細推導過程 --- 250
D. 二維平面規則堆積中粒子間孔隙度之估計法
------ 258
E. 以動態模擬所得濾性值預測過濾行為之方法
------ 26
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
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