本論文研究目標為：1. 描述台灣股票市場中訂單簿（order book）的若干特徵。2. 分析訂單流 (order flow) 與訂單簿間交互作用的均衡關係。 3. 探討流動性消耗者與流動性提供者如何進出市場而維持市場機能。 本研究資料來自台灣證券交易所。台灣股市的市場結構迥異於世界其他大部分的市場，採取自動化、間斷時間 (auto-electronic, periodic call) 的撮和方式：單子全部集合在交易所的電腦系統中，依照價格優先、時間優先的原則，每隔45至60秒批次執行撮和。Handa及Schwartz (1996年) 指出，這種市場結構和其他連續撮和的市場有著根本上的不同，尤其是訂單流的匯總方式與市場結清價的形成過程，但目前較少有研究提及。 在過去的文獻中，1995年Biais、Hillion及Spatt以巴黎股市中CAC 40指數的成分股為樣本，首開訂單流與訂單簿間交互作用的研究。他們直接觀察並描繪訂單在各價位的分佈情形，發現當買賣價差 (bid-ask spread) 比較大或訂單簿比較薄（亦即市場流動性較差）時，接下來會有比較多的限價單(limit orders)進場提供流動性；相反地，當spread比較小的時候，接下來會有比較多的市價單(market orders)進場消耗流動性。雖然他們有注意到買賣單、限價單、市價單對價格推升或壓低的作用，但對於引發這些變化的因素卻沒有進一步的闡釋。 1998年，Handa、Schwartz及Tiwari清楚地指出，短暫價格波動 (short-term volatility) 在促進市場達到流動性均衡方面扮演關鍵的角色。由於有基於流動性動機而進場的投資人，此時市價單與限價單成交所造成的短暫價格波動正好補償限價單交易者所面臨的資訊不對稱風險，吸引限價單進場並提供流動性；而有立即性(immediacy)需求的投資人就會下市價單而消耗流動性。1999年，Foucault把Handa等人的推論發展為賽局模型，強化下單決策與價格形成的理論，並建議以訂單流的組成成分進行實證。 這些理論在2000年Ahn、Bae和Chan發表的研究中獲得實證的支持。該文以市場深度差作為市價單限價單組成成分的代理變數，首先驗證短暫價格波動的確是使市場達流動性均衡的重要因素：當價格向上波動，將吸引限價單流入市場提供流動性；而流動性的增加將減緩價格的波動。並進一步分析價格形成過程，發現若價格波動由賣方引發，則限價賣單為流動性提供者；若價格波動來自買方，則限價買單為流動性提供者。 本研究不同於前述研究之處，其一在於台灣股票市場結構的不同。因為所有的單子，不論是新進入或殘留的、不論是買還是賣，全部都集合在電腦系統中等待撮和，因此限價單不見得是流動性提供者，市價單也不見得是流動性消耗者。其二在於直接觀察訂單分佈情形，比Biais等人更深入研究訂單變化、比Ahn等人更清楚地分析變化的過程。 本論文將市場中的單子區分為新委託單(new orders)、殘留單(stale orders)及成交單(executed orders)三大類，取得每個撮和時點前、後買賣雙方在各價位的分佈和變化情形。結果發現，大部分的新委託單並沒有立即成交（約40%沒有立即成交）；成交單中殘留單與新委託單成交的比例在任何時間區間都遠高於新委託單互相成交的比例。也就是說，殘留單對市場流動性的均衡扮演關鍵的角色。

Beginning in the early 1990s several countries, including Australia, have pursued programs of deregulation and restructuring of their electricity supply industries. Dissatisfaction with state-run monopoly suppliers and a desire for increased competition and choice for consumers have been the major motivations for reform. In Australia, the historical, vertically-integrated, government-owned electricity authorities were separated into separate generation, transmission, distribution and retail sectors in each State and a competitive, wholesale market for electricity, the National Electricity Market (NEM) began operation in December 1998. The goal of deregulation was (and remains) increased competition in electricity supply, so that consumers may enjoy wider choice and lower prices. The first benefit has largely been delivered but it is arguable whether the second benefit of lower prices has been realised. Increased competition has come at the price of increased wholesale price volatility, which brings with it increased cost as market participants seek to trade profitably and manage the increase in price risk. In the NEM, generators compete to sell into a pool market and distributors purchase electricity from the pool at prices determined by demand and supply, on a half-hourly basis. These market-clearing prices can be extremely volatile. Electricity prices are generally characterised by significant seasonal patterns, on an intra-day, weekly and monthly basis, as demand and supply conditions vary. Prices are also characterised by strong mean-reversion and extremely high spikes in price. While long-run mean prices typically range between $30 and $45 per megawatt hour, prices can spike to levels above $9,000 or $10,000 per megawatt hour from time to time. These spikes tend to be sporadic and very short-lived, rarely lasting for more than an hour or two. Although infrequent, spikes are the major contributor to price volatility and their evolution and causes need to be investigated and understood. The purpose of this thesis is to investigate and model Australian electricity prices. The research work presented is mostly empirical, with the early analytical chapters focusing on investigating the presence and significance of seasonal factors and spikes in electricity price and demand. In subsequent chapters this work is extended into analysis of the underlying volatility processes and the interaction between extreme values in demand and price is specifically investigated. The findings of the thesis are that while the characteristics of strong seasonal patterns and spikes that are generally observed in similar electricity markets are present in the NEM in both price and demand, there is significant variation in their presence and effect between the regional pools. The study also finds that while time-varying volatility is evident in the price series there is again some variation in the way this is characterised between states. A further finding challenges the accepted wisdom that demand peaks drive price spikes at the extremes and shows empirically that price spikes are more likely to be caused by supply disruptions than extremes of demand. The findings provide useful insight into this highly idiosyncratic but economically important national market.

Thesis (M. Phil.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Multilayered aluminium alloy composites were produced by accumulative roll bonding (ARB) to very high strain to generate sheet materials consisting of either 32 or 64 alternating layers of Al and Al-0.3w.%Sc alloy. Based on the starting heat treatment condition of the Al(Sc) alloy and the roll bonding temperature, several different Al/Al(Sc) combinations were produced: (i) SSSS-ARB (Al(Sc) in the supersaturated condition; Tdef = 200 ???C; 32 layers); (ii) Aged-ARB (Al(Sc) in the artificially aged condition; Tdef = 200 ???C; 32 layers), and (iii) SSSS-ARB-HT (Al(Sc) in the SSSS condition; Tdef = 350 ???C; 64 layers). Regardless of the roll bonding conditions, Al(Sc) in the form of a dispersion of ultrafine Al3Sc particles strongly impedes structural changes during thermomechanical processing whereas Al readily undergoes extensive dynamic and static restoration. The major aim of the thesis is to understand the effect of initial microstructure and processing conditions on microstructural development in these multilayered Al/Al(Sc) composites. The microstructures were investigated mainly by backscatter electron (BSE) and ion channeling contrast (ICC) imaging in the DualBeam Platform and transmission electron microscopy (TEM) whereas the crystallographic nature of the microstructures were investigated by electron backscatter diffraction (EBSD) and the various diffraction techniques available in the TEM. The mechanical properties of the materials were investigated by hardness and tensile testing. The deformation microstructure and texture of these two alloy combinations were strongly influenced by both the initial heat treatment condition of the Al(Sc) alloy whereby large-scale shear bands are generated during rolling when a dispersion of fine Al3Sc particles is present in the Al(Sc) layers. The deformation mechanism of both SSSS-ARB and Aged-ARB was strongly controlled by the relative hardening behaviour of adjacent layers. In Aged-ARB, a higher magnitude of in-plane shear stress, exceeding the flow stress of Al(Sc), was operative at the interfaces between layers; this was shown to cause the shear banding in this material. All materials were annealed for up to 6h at 350 ??C. This extended annealing generated alternating layers of coarse grains (Al layers) and a recovered substructure (Al(Sc) layers) with the substantial waviness of the layers in both Aged-ARB and SSSS-ARB-HT being inherited from the as-deformed material. While the Al(Sc) layers remain unrecrystallized in all materials due to particle pinning effects, the Al layers underwent continuous and discontinuous recrystallization after low and high temperature roll bonding, respectively. Shear banding in Aged-ARB also resulted in a reduction in intensity of the rolling texture components and had a randomizing effect on the recrystallization texture of the Al layers. The Al/A(Sc) multilayered composites were found to conform to the classic inverse strength/ductility relationship and no significant improvement in ductility (for a given strength) was evident. The barriers to achieving an excellent combination of ductility and strength (i.e. toughness) in these materials were identified to be delamination of the layers, which can be largely reduced (or eliminated) by careful control of starting materials (heat treatment condition and thickness) as well as the processing parameters during ARB.

TRIP-assisted multiphase steels exhibit an excellent balance of strength and ductility, which makes them very attractive for the automotive industry. These remarkable mechanical properties can be attributed mainly to the continuous transformation of retained austenite into martensite during straining (TRansformation Induced Plasticity). The aim of this thesis was to clarify the interaction between the hot rolling conditions, the formation of microstructure, and the resulting mechanical properties. Various rolling simulation techniques were employed to determine how the composite microstructure is formed during the various steps of multi-stage thermomechanical processing. The interaction between deformation and phase transformation is highlighted, particularly from the viewpoint of the transformation texture.

The microstructures and performance of Ni-based alloys and Ni-WC (nickel-tungsten carbide) composite overlays deposited by plasma transferred arc welding have been studied. The Ni-alloy overlays had similar microstructures consisting of Ni dendrites, with interdendritic Ni-based eutectics, borides and carbides. Low hardness alloy overlays contained a smaller fraction of interdendritic phases relative to the high hardness alloys. The interdendritic regions make a significant contribution to the hardness since they are more than twice as hard as primary dendrites. The Ni-WC composites contained similar phases, however WC dissolution was observed leading to the formation of other carbides. Ni-alloys with low carbon and Cr content exhibited the lowest WC dissolution. The Ni-WC overlays produced using these dilute alloys generally performed better in ASTM G65 wear tests. This was likely due to the reduced dissolution which avoided formation of brittle secondary phases, maintaining a short mean free path between WC particles and allowing increased impact energy absorption. / Materials Engineering

Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: Dionisios G. Vlachos, Dept. of Chemical Engineering. Includes bibliographical references.

Thesis (M.S.)--Brigham Young University. Dept. of Mechanical Engineering, 2005. / Includes bibliographical references (p. 115-118).

The way in which the myocardium responds to its mechanical environment must be understood in order to develop reasonable treatments for congestive heart failure. The first step toward this understanding is to characterize and quantify the cardiac microstructure in healthy and diseased hearts. Myocardium has a laminar architecture made up of myolaminae, which are sheets of myocytes surrounded by a collagen weave. By enhancing the contrast between the myocytes and the surrounding collagen, the myocardium can be investigated and its laminar structure can be quantified. Many of the techniques that have been used to view the microstructure of the heart require the use of toxic or caustic chemicals for fixation or staining. An efficient imaging method that uses polarization microscopy and enhances the contrast between the collagen and myocytes while minimizing the use of harmful chemicals was developed in this research. Collagen is birefringent; therefore its visibility should be enhanced through polarization microscopy and image processing. The sheet angles were viewed directly by cutting slices of a rat septum perpendicular to the fiber angle. Images of different polarization combinations were taken and a region of interest was selected on the sample. Image processing techniques were used to reduce the intensity variation on the images and account for the variable gain of the camera. The contrast between the collagen and myocytes was enhanced by comparing adjusted images to the background and looking at a single image this comparison produced. Although the contrast was enhanced, the embedding media reduced the collagen signal and the enhancement was not as striking as expected.

Copper has become the metal of choice for metallization, owing to its high electrical and thermal conductivity, relatively higher melting temperature and correspondingly lower rate of diffusivity. Most of the current studies can get high strength copper thin films but on an expense of conductivity. This study proposes a technique to deposit high strength and high conductivity copper thin films on different silicon substrates at room temperature. Single crystal Cu (100) and Cu (111) have been grown on Si (100) and Si (110) substrates, respectively. Single crystal Cu (111) films have a high density of growth twins, oriented parallel to the substrate surface due to low twin boundary energy and a high deposition rate. The yield strengths of these twinned Cu films are much higher than that of bulk copper, with an electrical resistivity value close to that of bulk copper. X-ray diffraction, transmission electron microscopy and nanoindentation techniques were used to show that high density twins are sole reason for the increase in hardness of these thin films. The formation of growth twins and their roles in enhancing the mechanical strength of Cu films while maintaining low resistivity are discussed.