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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
441

Effect of Coated Material on Cu Wire Bonding in IC Package

Jhuang, Yun-Da 04 September 2012 (has links)
Wire bonding has been used in integrated circuit packaging for many decades because of its high reliability and performance. The most common metal used has been gold, but with the surge in commodity prices of gold in recent years, copper wire is now used to altered gold wire for cost saving. Many challenges have to be solved to meet its application requirement; coating is one of the applications. In this study, a 3D coated copper wire and coated Al pad is built by finite element method to simulate ultrasonic bonding and thermosonic bonding. To consider the effect of coated material to stress and strain field on ultrasonic bonding and the effect of coated material to temperature field on thermosonic bonding. Then use the Taguchi experiment method to discuss the effect on Cu-Ball and Al pad under different coated material and thickness combination. The results show that with coated material on Al pad or copper wire could reduce more than 48% of effective plastic strain after the bonding process, it obviously reduce the Al splash phenomenon in copper wire bonding. But the coated material such like palladium and nickel which have lower thermal conductivity would resist the heat transfer. And the Taguchi experiment method shows that the most effective way to reduce the effective stress during impact stage and ultrasonic vibration stage is to increase the thickness of palladium and nickel respectively, and when the thickness of coated material Au reached 0.01£gm could increase the temperature of Cu-Ball and Al pad mostly.
442

On the use of cheap talk in hypothetical product valuation: a field experiment

Silva, Andres 15 May 2009 (has links)
Experimental willingness to pay (WTP) studies can be classified as hypothetical or non-hypothetical. In a hypothetical study, such as conjoint analysis, a subject does not need to make a real economic commitment. In contrast, in a non-hypothetical task such as in experimental auctions, a subject may need to actually buy the product. Subjects in hypothetical studies tend to overstate their true WTP. Consequently, researchers need to correct hypothetical values to obtain reliable WTP estimates. Recently, incentive-aligned and cheap talk approaches have been proposed as ways to correct for hypothetical bias. In a hypothetical task, a cheap talk script explicitly reminds the subject about the hypothetical nature of the task and its expected consequences. In an incentive-aligned task (non-hypothetical), subjects are randomly selected to physically buy the product. The objective of our study is to assess and compare the reduction of hypothetical bias in consumers’ willingness to pay for novel products by applying a generic, short, and neutral cheap talk script in a retail setting. To accomplish this objective, we employ non-hypothetical, hypothetical, and hypothetical with cheap talk treatments in our experimental design. We conducted our experimental retail study using conjoint analysis and open-ended elicitation mechanisms, utilizing Becker DeGroot Marshak (BDM) mechanism for the incentive-aligned treatments. Consistently in both elicitation mechanisms, using seemingly unrelated and random-effect Tobit techniques, we find that our cheap talk script is effective in eliminating the hypothetical bias. As expected, the hypothetical WTP values are significantly higher than the non-hypothetical values but the hypothetical values with cheap talk are not significantly different from incentive-aligned or non-hypothetical estimates. In addition, we find that open-ended estimates are significantly higher than conjoint analysis estimates and that emotions and familiarity can have significant impacts on WTP estimates.
443

Three essays on the effect of information on product valuation

Brummett, Robert George 15 May 2009 (has links)
Benefits and consequences of controversial products are debated in the public arena for the protection of consumers and to evaluate the market decisions made by industry and government. The food industry continues to develop new foods as well as processes to bring food to the market. Some of these processes bring to issue the safety of the products or the impact on the market, workers, or environment. Such controversial products or processes include BSE (mad cow disease), genetically modified organisms (GMO), antibiotics, pesticides, carbon monoxide modified atmosphere packaging, and food irradiation. This thesis sets out with the objective of understanding, developing, and utilizing methodologies similar to those used in other contingent valuation studies to evaluate how consumers are influenced by varying information using food irradiation as a focus subject. Food irradiation is a technological food process that continues to be debated and much information favoring and opposing it is readily available to the public, making it a suitable subject about which to study information effects and consumer acceptance. To accomplish this objective, consumers were surveyed in grocery stores in the state of Texas during the spring of 2006. As irradiated foods are not currently widely available, a hypothetical product, irradiated mangoes, was used to elicit information from survey participants. The survey was comprised of two parts. First general information regarding consumer knowledge and trust of food irradiation as well as willingness to pay (WTP) was collected. Second, varying information regarding food irradiation (positive, negative, or mixed) was presented and questioning was reaccomplished. Evaluation of the survey data was made in three papers, each comprising its own chapter in this thesis. The first paper evaluates consumers’ initial trust and knowledge of food irradiation and how these factors interact with information in changing WTP. The second paper assesses responses for a “cheap talk” effect. Cheap talk is informing consumers of the existence of hypothetical bias in studies of this type with the goal being to reduce this bias to real life response equivalence. The third paper evaluates not only WTP, but also how consumer trust is affected by varying forms of information.
444

Study on Single and Double Pumped Cr4+:YAG Crystal Fiber ASE Light Sour ce ¡V Simulation and Experiment

Huang, Yu-Chia 14 July 2004 (has links)
Owing to the increasing demand on the telecommunication bandwidth and the advent of the OH--free dry fiber developed by Lucent Technology, a new transmission bandwidth for the fiber optical communication which is centered around 1400 nm has been created in recent years. However, the corresponding light sources, optical amplifiers and other devices needed in the new transmission window are still under development. This thesis is to dissert with respect to the Cr4+:YAG crystal fiber based ASE (amplified spontaneous emission) light sources which emit light with broadband wavelengths from around 1200 nm to 1600 nm. Our previous study showed that side-pumping configuration can achieve a maximum ASE power of 0.65 mW with a pump power of 11 W at 980 nm in wavelength, whereas the end-pumping configuration successfully generated an optimum ASE power of 2.45 mW with a pump power of 11 W using a 1064-nm Yb fiber laser. This thesis reviewed the Cr4+:YAG material and studied on the single and double-pumping configuration of ASE light source, numerical simulations of the L-I curve of both configurations, and of the emission and the gain spectrum of the material, plus the introductions of the experiments needed for the simulations will be reported.
445

Analysis and Experimental Investigation on Energy Consumption of a Science and Technology Museum

Fan, Jia-wei 31 May 2005 (has links)
In this study, buildings in southern Taiwan area were selected to perform full-scale energy auditing experiment so that the energy consumption of each building can be analyzed comparatively. The result of experimental investigation and computer simulation were compared analytically with good accuracy obtained. The result can further facilitate as the design guide and energy indexes to be adapted in the national building energy code in the future
446

The study of framing and anchoring effect on Internet buyers' purchasing intention and price estimates

Wu, Chin-Shan 25 July 2005 (has links)
Internet has become a new form of mass media since its commercialization in early 1990¡¦s. While the transaction platform moves from bricks-and-motar to Internet, potential factors that influence consumers¡¦ purchase decisions changed. Because they cannot touch the product and interact with sales person, Internet buyers can only make decisions based on information presented on web pages. Under this circumstance, how the presentation of information such as advertisement and product description influence consumers¡¦ buying decision is an important issue. When the information is presented in different ways, people might make biased decisions. This study conducts four laboratory experiments which aim to investigate two decision biases in e-commerce context: framing effect and ancoring effect. The first two experiments focus on the framing effect and the last two experiments focus on the anchoring effect. Framing effect refers to the situation in which people¡¦s buying intention is influenced by different framing messages. Anchoring effect center on the situation in which people¡¦s price estimates are influenced by different anchor points presented in web pages. Three different kinds of framing messages which are formed by combining the attribute framing, goal framing and risky choice framing message and positive and negative presentation are considered in the first two experiments. Moreover, the subjects were assigned into two groups in different level of intrinsic self-relevence to understand whether it plays the moderating role in framing effect. In anchoring effect, in addition to the influence of high and low anchor points on subjects¡¦ price estimates, we also consider the moderating role of the operation of anchor points (one-way/two way), the reinforcement of anchor points (normal/intensified), and the relevancy between anchor and target (relevant/unrelevant). The results indicated that attribute framing effect is stable and is not influenced by subjects¡¦ level of intrinsic self-relevance, whereas the occurrence of goal framing effect and risky choice framing effect depends on the participants¡¦ level of intrinsic self-relevance. For subjects low in intrinsic self-relevance are more influenced by framing message and thus results in different buying intention or choices than those high in intrinsic self-relevance. This study also test and verify the robustness of anchoring effect. Estimaes made by participants in high and low anchor conditions is significantly different no matter the anchor is manipulated in one-way or two-way. In addition, the result of anchoring experiment supports the argument that the relevancy between anchor and target is important for the occurrence of anchoring effect. The moderating effect of anchor reinceforcement depends on the anchor was operated in one-way or two way condition. Anchoring effect is stable despite that the anchor is manipulated in normal or intensified condition when the anchor is manipulated in two-way. On the other hand, when the anchoring effect is manipulated in one-way condition, the anchor reinceforcement plays the role the moderator. Anchoring effect can be observed only when the anchor point is reinforced by appearing for three times. This study serves as a foundation for future study in e-commerce area. The procedures and experimental designs in this study can be either replicated or modified with a different sample to gather further evidence for the results discovered. Further, it can benefit practitioners in improving the design of e-commerce interfaces in real world applications.
447

The Experimental Investingation of Residual Strength and Stiffness in Carbon/PEEK APC-2 Composite Laminates

Wu, Chang-He 27 June 2001 (has links)
ABSTRACT AS-4 carbon fibers reinforced polyetheretherketone (PEEK) composite materials have been widely used in aerospace industry because of longer fatigue life, high specific stiffness and strength. The thesis is aimed to investigate the residual strength, residual stiffness and mechanical properties of thermoplastic AS-4/PEEK composite laminates subjected to tension-tension (T-T) cyclic loading at room temperature. We adopt modified diaphragm forming method by controlling temperature, pressure, vacuum and time conditions according to the obtained beast curing process to form composite laminates of low crystallinity, transcrystallinity and good fiber / matrix interfaces. Two common type of laminates are used, such as cross-ply [0/90]4S and quasi-isotropic [0/+45/90/-45]2S. Static tension test is performed to measure the elastic modulus and ultimate strength. And T-T fatigue test is conducted with maximum stress of 60% and 80% ultimate strength to find the residual strength and stiffness. Then, through the observation of failure surfaces of composite laminates we understand the failure initiation and mechanism by Scanning Electron Microscope (SEM). The results of experiment can be concluded as follows. The ultimate strength, elastic modulus and fatigue strength of cross-ply composite laminates are larger than those of quasi-isotropic. As centrally notched, the net area of the specimen is reduced, the ultimate strength and fatigue strength of composite materials are lower. The residual strength, adopted to describe the damage process, is monotonically decreasing with increasing of applied cycles. It is found that the residual strength of cross-ply laminates is larger than that of quasi-isotropic laminates. However, the residual stiffness has little change with increasing of applied cycles.
448

Die Kollagenmatrix archäologischer Funde im Vergleich zu künstlich gealterten Ledermustern historischer Gerbverfahren

Trommer, Bernhard 14 July 2009 (has links) (PDF)
Ausgangspunkt der wissenschaftlichen Arbeit bildet eine Recherche historischer Leder- und Gerbarten. Die Quellen wurden auf ihren technologischen Wahrheitsgehalt überprüft. Dazu wurden über 30 Rezepturen historischer Gerbarten entwickelt und halbtechnisch erprobt. Im Ergebnis entstanden Referenzleder, welche analysiert und experimentell auf ihr Alterungs- und Abbauverhalten untersucht wurden. Die klassischen Methoden der Lederprüfung, die Elektronenstrahlmikroskopie (SEM/ EDX), die UV- und FT-IR-Spektroskopie, RP-HPLC- sowie die DSC-Analyse wurden für die Untersuchung der Referenzleder benutzt und weiterentwickelt. Die Erkenntnisse aus Recherche, technologischer Rekonstruktion, Simulation und Analyse wurden an archäologischen Lederfunden evaluiert. Das Alter der untersuchten Funde umfaßt eine Zeitspanne von 100 bis 3.300 Jahren. Bei der Wahl der Objekte wurde auf ein unterschiedliches Fundortmilieu Wert gelegt, um die Auswirkungen typischer Standortbedingungen auf die Ledermatrix zu erforschen.
449

Préparation de l'expérience ATLAS auprès du futur grand collisionneur de protons LHC : performances du calorimètre électromagnétique et potentiels pour la physique du quark top

Hubaut, F. 29 March 2007 (has links) (PDF)
Ce mémoire présente une synthèse des travaux que j'ai effectués depuis 7 ans pour la préparation de l'expérience ATLAS, devant fonctionner auprès du futur grand collisionneur de hadrons du CERN, le LHC, qui entrera en service en 2008.
450

Elevers inställning till NO och Teknik i år 4-6 / Pupil’s attitude to natural science and technology in grade 4-6

Magnusson, Linda January 2007 (has links)
<p>Syftet med examensarbetet var att undersöka vilken inställning elever har till NO och teknik. I undersökningen användes enkäter som är utformade som intervjublad, med öppna svarsfrågor, vilket gör att det är elevernas tankar som framkommer i svaren. Det är 320 elever från fyra olika skolor i årskurserna 4-6, som är med i studien. Detta för att resultat mellan skolor skulle kunna jämföras. Av resultaten framgår att de flesta eleverna har en positiv inställning till NO och teknik. De kommer med bra svar till varför de tror att ämnena är viktiga i undervisningen. Men de har också svårt att skilja på om de har NO eller teknik i undervisningen. Det är ingen större skillnad mellan skolorna på svaren från eleverna. Vi måste uppmärksamma eleverna på när NO respektive teknik sker i undervisningen och relatera ämnena till vardagslivet, så eleverna får förståelse för när de kan använda det de lär sig. Vilket kan göra att elevernas motivation och intresse ökar för dessa.</p>

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