1,720,992 research outputs found
Steady-state Rheological Parameters Test of the Vertical Rotating Viscometer
No full text本研究主要以數學理論推導再配合實驗分析數據、檢定參數，目的是了解在垂直旋轉式流變儀中穩態流體之流變關係，理論方面由賓漢流體模式作為本構關係式，將流體分為強剪層與弱剪層，在穩態二維不可壓縮的假設下，應用長波理論並正規化控制方程式與邊界條件進行尺度分析簡化方程式，計算求得各變數之第零階解，推導得到流體在垂直旋轉式流變儀中的流變參數檢定公式，並使用該檢定式研究高嶺土漿體在流變儀中的流變特性，最後分析得到的結果，希望能對未來土石流相關研究有所幫助。實驗方面流變儀中高嶺土漿體流況會受到體積、轉速、濃度影響，觀察高嶺土溶液在垂直旋轉式流變儀的運動型態並記錄流變參數檢定所需相關數據，實驗體積分為6000ml、9000ml、12000ml三種，濃度範圍為20%~50%，轉速範圍從3.5rpm 到43rpm ，流況分類依據為艾(2009)研究中對高嶺土溶液運動型態的定義。實驗結果分析顯示，高嶺土漿體在流變儀中的流變參數會與高嶺土溶液的重量百分濃度呈正相關，不同的實驗體積並不影響流變參數，運動型態分析上，較大的體積流況的穩定與不穩定分界點出現在較高的濃度，最後根據流變參數檢定式繪出最大流深、最大流深角度、密度、半徑、降伏剪應力之無因次關係圖，以供參數檢定工作之使用
Novel Aromatic Polyimide-Nanocrystalline-Titaniaybrid Optical Films with High Refractive Index
No full text芳香族聚醯亞胺是眾所皆之的高熱安定性及高折射率材料，因此在學術研究及光電元件的應用上十分廣泛，但是其應用性受限於低溶解度及難熔性。導入羥基於聚醯亞胺結構中是一個重要的方法，不僅可以有效地提升溶解度，並且提供了有機及無機材料鍵結的反應位置。由於有機/無機混成材料較其單一材料具有機械性質、熱性質、及光學性質上的提昇效果，因此近年來已逐漸受到重視及研究。本論文的研究目標為設計與合成出新穎的高分子/二氧化鈦混成材料並探討其在光學膜上的應用，進而製作出色淡、透明性、高折射率光學膜。第二章中，首先合成兩種新型含羥基的二胺單體2,3-bis(4-amino-3-hydroxyphenoxy)naphthalene 及2,7-bis(4-amino-3-hydroxyphenoxy)naphthalene，並聚合出兩系列新穎的可溶性聚醯亞胺。具有羥基的聚醯亞胺與四丁基鈦可進一步藉由控制有機/無機莫耳比例成功地製備有機/無機混成光學材料。此光學薄膜(100-500 nm)的折射率可由二氧化鈦含量自由地調控(n介於1.67-1.99)。更進一步，我們成功合成出二氧化鈦含量達50 %的光學厚膜，此光學厚膜(20-30 μm)的折射率及二氧化鈦含量皆高過於至今的所有文獻。此系統的光學厚膜亦具有高撓曲性、高機械強度、出色的熱性質、低熱膨脹係數、高折射率，及可見光區的高穿透度。 在第三章中，導入六氟基團於具有羥基的聚醯亞胺中，更有效地增加了材料的溶解度。一系列的高折射率及高光學透明性的聚醯亞胺-二氧化鈦混成光學材料也成功地合成，其光學薄膜(100-1000 nm)的折射率可由二氧化鈦含量自由地調控(1.61-1.99)。此有機/無機光學厚膜(20-30 μm)亦具有高撓曲性、高機械強度、出色的熱性質、低熱膨脹係數、高折射率，及可見光區的高穿透度。Aromatic polyimides are well known as excellent heat-resistant and high refractive index materials which have been widely investigated and applied for optoelectronic devices. However, their applicability has been limited because of the normally insolubility and infusibility in the fully imidized form. The incorporation of hydroxyl groups on the backbones of the polyimides was an important strategy to ensure the solubility and provided the reactive sites for organic-inorganic bonding. Composites that consist of polymer–inorganic hybrid materials have recently attracted considerable interests due to their enhanced mechanical, thermal, optical properties compared to the corresponding individual inorganic or polymer component. The research goals of this thesis were design and synthesis of novel polymer/titania hybrid materials and investigated their applications in optical films. Furthermore, the lower colorness, high optical transparency, and high refractive index optical films could also be prepared.hapter 2 included two series of novel soluble polyimides with hydroxy-substituted which were synthesized from the new diamines, 2,3-bis(4-amino-3-hydroxyphenoxy)naphthalene and 2,7-bis(4-amino-3-hydroxyphenoxy)naphthalene, with various commercial tetracarboxylic dianhydrides, respectively. High refractive index polyimide–titania hybrid optical films were successfully prepared from the soluble hydroxy-substituted polyimides and titanium butoxide by controlling the organic/inorganic molar ratio. The tunable refractive index (1.67-1.99) of hybrid thin films (100-500 nm) could be obtained by controlling titania content. Moreover, the thick titania hybrid films could also be achieved even with the relatively high titania content as high as 50 wt%. To the best of our knowledge, the refractive index and titania content are the highest to date among the polymer–titania hybrid optical films (20-30 µm in thickness). All these obtained hybrid thick films revealed excellent thermal properties with low CTE, good mechanical properties and flexibility, high refractive index, and good optical transparency in the visible region.hapter 3 showed the effective approach of improving the solubility of aromatic polyimides by incorporation of the hexafluoroisopropylidene (6F) and hydroxyl groups into polymer backbone. High refractive index and optical transparency polyimide–titania hybrid optical films were also successfully prepared. The refractive index (1.61-1.99) of hybrid thin films (100 nm-1000 nm) could be obtained by tuning titania content, and the hybrid thick films (20-30 µm) also exhibited enhanced mechanical properties and good flexibility, excellent thermal properties with lower CTE, high refractive index, and good optical transparency in the visible region.TABLE OF CONTENTSBSTRACT (in English)………………………………….…………….. iBSTRACT (in Chinese)……………………………………….…….....iiiABLE OF CONTENTS………………………………………….…….. ivIST OF TABLES………………………...…………………….……… ixIST OF FIGURES…………………………………………………….. xiHAPTER 1………………………………………………………….......1HAPTER 2…………………………………………………………….44HAPTER 3……………………………………..………………….....109HAPTER 1eneral Introduction.1 HIGH PERFORMANCE POLYMERS……………………………........................2.1.1 Preparation of Aromatic Polyimides ...............................................................4.1.2 Modification of Aromatic Polyimides.............................................................6.1.3 Modification of PI by Incorporation of Hydroxyl Group................................9.1.4 Modification of PI by Incorporation of Naphthalene....................................10.2 HIGH REFRACTIVE INDEX MATERIALS........................................................11.3 FUNCTIONAL HYBRID ORGANIC-INORGANIC NANOCOMPOSITES......16.3.1 Background of Sol-gel Chemistry..................................................................20.3.2 Titania Based Hybrid Nanocomposites..........................................................24.3.3 Hydrothermal Crystallization…………………………..................................25.3.4 Titania-Polyimide Hybrids………………………….......................................27.4 OPTICAL AFFECT OF HYBRID NANOCOMPOSITES......................................33.5 RESEACH MOTIVATION……………………………….......................................34EFERENCES AND NOTES.......................................................................................35HAPTER 2acile Preparation for Nanocrystalline-Titania Hybrids From Hydroxy-Containing Polyimide: Novel Flexible PI-TiO2 Optical Films with High Refractive Index, Good Optical Transparency, and Excellent Thermally Dimensional StabilityBSTRACT OF CHAPTER 2.......................................................................................45.1 INTRODUCTION....................................................................................................46.2 EXPERIMENTAL SECTION...................................................................................49 2.2.1 Materials...........................................................................................................49 2.2.2 Monomer Synthesis.........................................................................................49 2,3-bis(3-benzyloxy-4-nitrophenoxyl)naphthalene (2,3-2)............................49 2,3-bis(4-amino-3-hydroxyphenoxy)naphthalene (2,3-3)…..........................50 2,7-bis(3-benzyloxy-4-nitrophenoxyl)naphthalene (2,7-2)............................51 2,7-bis(4-amino-3-hydroxyphenoxy)naphthalene (2,7-3)..............................51 2.2.3 Polymer Synthesis...........................................................................................57 2.2.4 Preparation of the Films..................................................................................59 2.2.5 Preparation of Polyimide-Titania Hybrid Films.............................................59 2.2.6 Preparation of Titania Films (TP100)……………….....................................65 2.2.7 Measurements.....................................................................................................65.3 RESULTS AND DISCUSSION..................................................................................67 2.3.1 Monomer Synthesis........................................................................................67 2.3.2 Polymer Synthesis...........................................................................................68 2.3.3 Polymer Properties............................................................................................73asic Characterization..................................................................................73ptical Properties.........................................................................................76 2.3.4 Hybrid Properties..............................................................................................79tructural characterizations…………...........................................................79hermal Properties…...................................................................................81orphology Analyses...................................................................................89ptical Properties.........................................................................................97ultilayer antireflection coatings...............................................................104.4 SUMMARY............................................................................................................106EFERENCES AND NOTES.....................................................................................107HAPTER 3ew Approaching for Organic-Inorganic Hybrids Based on Hydroxy-Containing 6F-Polyimide: Novel Flexible PI-TiO2 Optical Films with High Optical Transparency, Tunable Refractive Index, and Excellent Thermal StabilityBSTRACT OF CHAPTER 3....................................................................................110.1 INTRODUCTION.................................................................................................111.2 EXPERIMENTAL SECTION...............................................................................114 3.2.1 Materials..........................................................................................................114.2.2 Polymer Synthesis...........................................................................................114 3.2.3 Preparation of Polyimide-Titania Hybrid Films...........................................114 2.2.6 Preparation of Titania Films (TP100)………………...................................118 2.2.7 Measurements...................................................................................................118.3 RESULTS AND DISCUSSION...............................................................................120 3.3.1 Polymer Synthesis........................................................................................... 120 3.3.2 Polymer Properties........................................................................................122asic Characteristion..................................................................................122 3.3.3 Hybrid Properties............................................................................................124tructural characterizations……….............................................................124hermal Properties….................................................................................124orphology Analyses..................................................................................131ptical Properties.......................................................................................137ultilayer antireflection coatings...............................................................144.4 SUMMARY............................................................................................................146EFERENCES AND NOTES.....................................................................................147 LIST OF TABLESHAPTER 1.1 Some Typical Aromatic High Performance Polymers............................................3.2 Commercially Available Aromatic Polyimides.......................................................5.3 Some Soluble Aromatic Polyimides.......................................................................8.4 Refractive Index and Absorption Coefficients at Three Different Wavelengths in The Visible Range for Some Inorganic Materials................................................14.5 Components, Synthesis Method and RI of Some Metal Oxide–Polymer Nanocomposites with High RI……......................................................................15.6 Properties of Conventional Organic and Inorganic Components.........................19.7 Electronegativity (χ), Coordination Number (N), and Degree of Unsaturation (N - Z) of Some Metals (Z=4)…………………........................................................20HAPTER 2.1 Reaction Composition and Properties of The 2,3-PHIc Hybrid Films...............62.2 Reaction Composition and Properties of The 2,7-PHIc Hybrid Films...............63.3 Inherent Viscosities and Elemental Analysis of Polyimides................................69.4 Inherent Viscosities and GPC Data of Polyimides..............................................72.5 Solubility of Polyimides......................................................................................74.6 Thermal Properties of Polyimides.......................................................................75.7 Thermal Properties of 2,3-PHIc Hybrid Materials.............................................83.8 Color Coordinates and Cutoff Wavelength (λo) from UV-Vis Spectra of 2,3-PHIc Hybrid Materials ……………………………...…...………………103HAPTER 3.1 Reaction Composition and Properties of the 6FPI Hybrid Films......................116.2 Inherent Viscosity and GPC Data of Polyimide.................................................120.3 Solubility of Polyimide........................................................................................123.4 Thermal Properties of 6FPI Hybrid Materials...................................................126.5 Color Coordinates and Cutoff Wavelength (λo) from UV-Vis Spectra of 6FPI Hybrid Materials……………………………………………………………….........143IST OF FIGURESHAPTER 1.1 The different types pf hybrid materials...................................................................17.2 Selected interactions typically applied in hybrid materials and their relative strength………………………………......................................................................18.3 Schematics of size control in in situ composite synthesis....................................18.4 Polymerization behavior of aqueous silica...........................................................22.5 The images and the crystal structures of anatase, rutile and brookite..................24.6 Reaction scheme for hydrothermal crystallization of anatase...............................26.7 Thickness and refractive index of the sol-gel titania film at different annealing temperatures, green dots are thickness, and purple triangles are refractive index at 632.8 nm……………………………………………………………………...26.8 Left: Reaction scheme for the preparation of the aminoalkoxysilane capped PMDA–titania films; right: refractive index, extinction coefficeint versus titania fraction.................................................................................................................29.9 The synthetic procedure used to produce TiO2/BTDA–DMMDA......................30.10 Left: flow chart of the procedures to prepare the PI/TiO2 hybrid films;right: TEM photographs and selected-area electron diffraction(SAED) patterns…………...31.11 Left: Chemical structures of monomers and polymers; right: steps involved in the synthesis of polymer-trapped titania nanoclusters……………………………...31.12 Semi-alicyclic sulfur-containing PAA and silica-modified anatase TiO2…........32.13 (a) Reaction scheme for the preparation of the carboxylic acid end groups PI–titania films; (b) refractive index (c) UV-Vis-NIR absorption spectra….…...32.14 Scheme of light scattering loss for traditional composites and nanocomposites.............................................................................................................33HAPTER 2.1 (a) 1H NMR and (b) 13C NMR spectra of compound 2.3-2 in DMSO-d6...........53.2 (a) 1H NMR and (b) 13C NMR spectra of compound 2.3-3 in DMSO-d6...........54.3 (a) 1H NMR and (b) 13C NMR spectra of compound 2.7-2 in DMSO-d6...........55.4 (a) 1H NMR and (b) 13C NMR spectra of compound 2.7-3 in DMSO-d6...........56.5 The photo of high refractive index, flexible, and good transparent polyimide (2,3-PHIc)-nanocrystalline-titania (2,3TP50) hybrid optical films (thickness=20~30 μm)………………………………………………………….64.6 The photo of high refractive index, flexible, and good transparent polyimide (2,7-PHIc)-nanocrystalline-titania (2,7TP50) hybrid optical films (thickness=20~30 μm)...........................................................................................64.7 The FTIR spectrum of (a) 2,3-PI (without OH) (b) 2,3-PHIc..............................70.8 The FTIR spectrum of 2,7-PHIc.........................................................................71.9 Transmittance UV-visible spectra of 2,3-PHI (thickness:1-3 μm)………….....77.10 Variation of the refractive index of 2,3-PHI........................................................78.11 Variation of the refractive index of 2,7-PHI………………………...…..….….78.12 FTIR spectra of the studied films (a) 2,3-PHIc (b) 2,3TP50……......…..……..79.13 FTIR spectra of the studied films (a) 2,3-PHIc (b) 2,3TP50……......…..……..80.14 TGA thermograms of 2,3-PHIc hybrid materials in N2......................................84.15 TGA thermograms of 2,3-PHIc hybrid materials in air………............................84.16 TGA thermograms of 2,7-PHIc hybrid materials in N2......................................85.17 TGA thermograms of 2,7-PHIc hybrid materials in air………............................85.18 DSC curves of the 2,3-PHIc hybrid at a heating rate of 10 oC/min under a nitrogen flow………………………………………...........................................86.19 TMA curve of 2,3TP10 with a heating rate of 10 oC/min……………….…......87.20 (a) Storage modulus and (b) Tan delta curves of 2,3-PHIc hybrid materials......88.21 SEM image of the 2,3-PHIc hybrid materials (a)2,3TP50 (coat on glass) (b)2,3TP70 (coat on glass) (c)2,3TP50 (film) (d) 2,3-PI (without OH)&TiO2(30%).................................................................................................90.22 SEM image of the 2,7-PHIc hybrid films coated on glass (a) 2,7TP50(film, thickness20~30 μm) (b) 2,7TP70(coat on glass, thickness100~500 nm)............92.23 AFM of the 2,3TP50 hybrid films coated on glass (a) phase images (b) height images; 2,3TP70 hybrid films coated on glass (c) phase images (d) height images..................................................................................................................93.24 AFM of the 2,7TP50 hybrid films coated on glass (a) phase images (b) height images; 2,7TP70 hybrid films coated on glass (c) phase images (d) height images..................................................................................................................94.25 TEM images of the 2,3-PHIc hybrid materials (a) 2,3TP50 and (b) 2,3TP70...95.26 XRD patterns of the 2,3-PHIc and 2,3TP10-2,3TP70 hybrid materials……....96.27 Variation of the refractive index of the 2,3-PHIc hybrid materials 2,3TP0-TP100,with wavelength.The insert figure shows the variation of refractive index with titania content....................................................................99.28 Variation of the refractive index of the 2,7-PHIc hybrid materials 2,7TP0-TP100,with wavelength.The insert figure shows the variation of refractive index with titania content..................................................................100.29 Transmittance UV-visible spectra of 2,3-PHIc and 2,7-PHIc (thickness: 1-3 μm)…………………………………………………………………...……….101.30 Transmittance UV-visible spectra of 2,3-PHIc hybrid materials (thickness: 0.1-0.5 μm)…………………………………………………………………... 102.31 Transmittance UV-visible spectra of 2,3-PHIc hybrid materials (thickness: 20-30 μm)………...………………………………………………….………..102.32 Variation of the reflectance with wavelength: (a) optical glass and (b) the three-layer anti-reflection coating. The insert figure shows the structure of the three-layer anti-reflection coating. ……………………………….…………..105HAPTER 3.1 The photo of high transparent, flexible, and refractive index polyimide (6FPI)-nanocrystalline-titania (6TP50) hybrid optical films (thickness:20~30 μm).......................................................................................................................117.2 FTIR spectra of the studied films (a) 6FPI (b) 6TP50.......................................121.3 TGA thermograms of 6FPI hybrid materials in N2............................................127.4 TGA thermograms of 6FPI hybrid materials in air........................................ ...128.5 TMA curve of 6TP30 with a heating rate of 10 oC/min.................................... 129.6 (a) Storage modulus and (b) Tan delta curves of 6FPI hybrid materials...........130.7 SEM image of the 6FPI hybrid materials (a) 6TP50 (film) (b) 6TP70 (coat on glass).....................................................................................................................133.8 AFM of the 6TP50 hybrid films coated on glass (a) phase images (b) height images; 6TP70 hybrid films coated on glass (c) phase images (d) height images.................................................................................................................134.9 TEM images of the 6FPI hybrid materials (a) 6TP50 and (b) 6TP70..............135.10 XRD patterns of the 6FPI and 6TP10-6TP70 hybrid materials........................136.11 Variation of the refractive index of the 6FPI hybrid materials 6TP0-TP100, with wavelength.The insert figure shows the variation of refractive index with titania content............................................................................................................ ...139.12 Variation of the extinction coefficients of the polyimide-titania hybrid films in the range of 300 –800 nm……………………………………………….... ......140.13 Transmittance UV-visible spectra of 6FPI hybrid materials (thickness: 0.1-1.0 μm)..................................................................................................................... 141.14 Transmittance UV-visible spectra of 6FPI hybrid materials (thickness: 20-30 μm)………………………………………………………………….................142.15 Variation of the reflectance with wavelength: (a) optical glass and (b) the three-layer anti-reflection coating. The insert figure shows the structure of the three-layer anti-reflection coating......................................................................14
Sulfation and Carbonation of Basic Oxygen Furnace Slag/Ca(OH)2 Sorbents at High Temperatures.
No full text本研究以微分固定床反應器探討燃煤廢氣成分(SO2、CO2、O2、H2O和NOx)對氫氧化鈣(HL)、轉爐爐石(BOFS)以及HL/BOFS(9/1)吸收劑在高溫下的硫酸化與碳酸化反應之影響。
各吸收劑硫酸化反應轉化率隨反應溫度(750-950℃)和SO2(1000-5000ppm)上升而上升。Ca(OH)2和HL/BOFS(9/1)吸收劑之轉化率大約相同，皆高於BOFS。與Ca(OH)2或BOFS在二氧化硫/氧氣/氮氣中反應的結果比較，水氣單獨加入反應氣體中、水氣與氮氧化物同時加入，以及在氮氧化物存在時增加氧氣濃度，皆明顯促進氫氧化鈣之硫酸化反應，其餘氣體組成條件則無影響；對BOFS而言，單獨加入氮氧化物，以及高濃度水氣(20%)與二氧化碳同時存在時，會明顯降低其硫酸化反應，但其餘氣體組成條件則有助益。
氫氧化鈣最佳碳酸化溫度為600℃。提高二氧化碳濃度(13%~80%)能促進碳酸化反應。在600℃、13%CO2和5%O2反應1分鐘與1小時的轉化率分別為0.88和0.93；BOFS在相同條件下反應1小時轉化率為0.24。NOx會輕微抑制氫氧化鈣碳酸化反應，但當氮氧化物與水氣同時加入時，或單獨加入水氣時則無影響。添加氮氧化物對BOFS碳酸化無影響，而水氣存在時有輕微促進作用。二氧化硫與二氧化碳同時存在下，降低反應溫度(600~750℃)、降低SO2濃度和提高CO2濃度，明顯降低硫酸化轉化率、提升碳酸化轉化率。在600℃、13%CO2、5%O2和1000ppmSO2下反應10分鐘後，Ca(OH)2的碳酸化和硫酸化轉化率分別為0.91和0.07，BOFS為0.24和0.07，HL/BOFS為0.78和0.03。The effects of compoments of flue gas generated from coal combustion on the sulfation and carbonation reactions of Ca(OH)2(HL), basic oxygen furnace slag(BOFS), and HL/BOFS(9/1) sorbents at high temperatures were studied using a differential fixed-bed reactor.
The sulfation rate for each sorbent increased with increasing reaction temperature(750-950℃) and SO2 concentration(1000-3000ppm). The conversions for Ca(OH)2 and HL/BOFS(9/1) were about the same and higher than that for BOFS.For Ca(OH)2, compared to the case of reaction under SO2/O2/N2 mixture, adding H2O alone, or adding H2O and NOx simultaneously, or increasing the O2 concentration(from 5% to 20%) when NOx was added enhanced the sulfation reaction, while the other gas compositions had little effect. For BOFS, adding NOx alone, or increasing H2O concentration(from 10% to 20%) when both H2O and CO2 were added inhibited the sulfation reaction, while the other gas compositions had enhancing effects.
The optimum carbonation temperature was 600℃for Ca(OH)2. The carbonation conversion increased as CO2 concentration (13%-80%) increased. Conversions of 0.88 and 0.93 were achieved when Ca(OH)2 reacted at 600℃,13% CO2, 5% O2 for 1min and 1h, respectively. An 1h conversion of 0.24 was achieved when BOFS was carbonated at same conditions. The presence of NOx slightly inhibited the carbonation of Ca(OH)2, while the precence of H2O or H2O/NOx had little effect. For the carbonation of BOFS, the presence of NOx had little effect and the presence of H2O had a slight enhancement effect. When both SO2 and CO2 were present, the carbonation conversion increased and the sulfation conversion decreased significantly with decreasing reaction temperature (600-750℃) or SO2 concentration (1000-5000ppm) and with increasing the CO2 concentration. The carbonation and sulfation conversions achieved for a sorbent reacted at 600℃,13% CO2, 5% O2 and 1000ppm SO2 for 10min were 0.91 and 0.07 for Ca(OH)2, 0.24 and 0.07 for BOFS, and 0.78 and 0.03 for HL/BOFS, respectively
Real-Time Physics-Based Human Legs Balancing Simulation
No full text本論文提出了一個嶄新的動作合成問題，根據上半身的動作軌跡產生出對應的下半身運動軌跡，並且讓這個動作在物理模擬引擎運算的時候可以令整個身體維持平衡，而為了解決這個問題，我們利用增強式學習，讓電腦能夠在不斷的進行嘗試之後找到一個最好的策略來應付不同的上半身運動軌跡。當一個上半身的運動軌跡進入到我們系統，首先會對這個只有上半身的動作進行一次簡單的物理模擬，藉此從中擷取出這個動作的一些特徵，再輸入事前已經訓練好的類神經網路模型，而這個網路模型所得到的響應就會是我們下半身相對應動作的特徵，之後再經過一個轉換演算法將下半身動作的特徵轉換成動作軌跡，將這個動作軌跡與原本的上半身動作軌跡結合起來同時驅動的話，就是我們最後所得到的動畫。利用增強式學習讓電腦自行學習出平衡的策略方法，可以讓我們不需要過度的花費時間在尋找及調整以往利用最佳化方法時所需的目標函數以及限制函數，並且這種方法也比較符合人類在初學一個新的動作時大腦及身體在運作的方式。In this thesis we propose a new motion synthesis problem. For an upper body movement as input, system generates a corresponding lower body movement. When they animate at the same time in a physical simulation software, the human model should maintain body balance. To solve this problem, we try to use reinforce learning to let computer find the best control policy during iteratively testing and improving to adjust different upper body movement. When set an upper body movement as system input, first we execute a physical simulation for the upper-body-only movement to extract features of the movement. Then we pass these to a learned neural network model. The responses of the model is the features of corresponding lower body movement. We use a decoding algorithm to transfer output features to the lower body movement trajectory. In the last, we animate upper and lower body movement at the same time, it will be the final animation. This method makes us not to cost too much time in searching or revising objective and constraint function in traditional optimization methods. Also, the method is much like a human start to learn a new movement or skill
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
- …
