Dissertations / Theses on the topic 'Temperature-dependent'
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Sansom, Ahmos. "Spreading gravity currents with temperature-dependent viscosity." Thesis, University of Nottingham, 2000. http://eprints.nottingham.ac.uk/14140/.
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The spreading of a fluid under gravity has many important industrial and geophysical applications and has been the focus of much research. Variations in the thermal properties of the fluid have often been neglected. This thesis introduces a series of models incorporating fluids having temperature-dependent viscosity and vertical cross-sectional profile of small aspect ratio to show the important effects that cooling can have on the flow field. The numerical results show features that are commonly observed in experiment and lava dome growth, such as plateauing and fingering.
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Therrien, Corie L. "Conservational implications of temperature-dependent sex determination." Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2008r/therrien.pdf.
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Yang, Yun. "Temperature dependent PCDD/PCDF product distributions from phenols." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/20182.
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Fuller, Jason C. "Temperature dependent control of community energy storage devices." Pullman, Wash. : Washington State University, 2010. http://www.dissertations.wsu.edu/Thesis/Spring2010/j_fuller_042310.pdf.
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Thesis (M.S. in electrical engineering)--Washington State University, May 2010.Title from PDF title page (viewed on July 15, 2010). "School of Electrical Engineering and Computer Science." Includes bibliographical references (p. 71-75).
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Huang, Yan, and 黃燕. "Temperature dependent hall effect: studies ofGaN on sapphire." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B42577068.
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Falasco, Gianmaria, Manuel V. Gnann, Daniel Rings, Dipanjan Chakraborty, and Klaus Kroy. "Effective time-dependent temperature in hot Brownian motion." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-183309.
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Chiu, Kwong-Shing Kevin. "Temperature dependent properties and microvoid in thermal lagging /." free to MU campus, to others for purchase, 1999. http://wwwlib.umi.com/cr/mo/fullcit?p9962510.
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Falasco, Gianmaria, Manuel V. Gnann, Daniel Rings, Dipanjan Chakraborty, and Klaus Kroy. "Effective time-dependent temperature in hot Brownian motion." Diffusion fundamentals 20 (2013) 63, S. 1-2, 2013. https://ul.qucosa.de/id/qucosa%3A13640.
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Lu, Yang. "Temperature dependent visco-elastoplastic evaluation of flexible pavements." Thesis, London South Bank University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.618649.
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Hai, Md. "Minimizing temperature dependent spectral shift in SOI DPSK demodulators." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104852.
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Silicon on insulator (SOI) photonic devices are becoming popular due to their compatibility with complementary metal oxide semiconductor (CMOS) technology. Over the last five years, we have seen several practical demonstrations of high-speed optical modulators, switches, filters designed on SOI platform. Some of these devices were made utilizing one fundamental property of light: Interference. However, interference-based SOI devices show disastrous spectral phase shift with temperature change which result in the necessity of integrating active temperature control circuits to stabilize them. In this work we present a 50 Gb/sec SOI Mach-Zehnder interferometer (MZI) differential phase shift keying (DPSK) demodulator which exhibits over 90% improvement in thermal stability with 0.05 nm/C of its spectral profile compared to 0.9 nm/C for a noncompensated demodulators. Our proposed method is a fully passive way of minimizing temperature dependant spectral shift in DPSK demodulators, which employs the waveguide engineering method. A full analytical approach to address the problem is derived first, which is followed by extensive numerical simulations to find out the exact device dimensions. Through this, we present a step by step approach to design the demodulator by achieving required waveguide geometry. After we get the design values of our device parameters we calculate the spectral shift with temperature change by our customized computer program and observe improved performance of the device with temperature change. With the values of design variables, we fabricate our device through Canadian Microelectronics Corporation (CMC). The waveguide width of our device varies from 280 nm to 450 nm at different stage of the device while its height was fixed to 220 nm. For thermally non-compensated demodulator, waveguide width was 450 nm throughout the device. Both thermally compensated and non-compensated demodulators are built on the same chip. Experimental result of the fabricated device is presented and we compare different performance metric of the demodulator with and without the proposed temperature compensation technique.La recherche sur les composantes photoniques en silicium sur isolant (SOI) est devenue populaire en raison de leur compatibilité avec la technologie des semi-conducteur en métal complémentaire d'oxyde (CMOS). Pendant les cinq dernières années, nous avons vu plusieurs démonstrations pratiques de modulateurs optiques à grande vitesse, de commutateurs, et de filtres en SOI. Certaines de ces composantes utilisent une propriété fondamentale de lumière : l'interférence. Pourtant, les composantes en SOI à base d'interférence montrent un changement de phase spectral désastreux avec le changement de température qui s'ensuit d'une nécessité d'intégrer des circuits de contrôle actifs de température pour les stabiliser. Dans ce travail nous présentons un interféromètre Mach-Zehnder (MZI) en SOI à 50 Gb/sec pour la modulation de phase différentielle (DPSK). Le démodulateur a une stabilité thermale de 0.05 nm/0C qui est 90% meilleure que les démodulateurs non-compensés qui eux ont un profil spectral de 0.9 nm/0C. Notre méthode propose une façon complètement passive de minimiser l'effet de la température sur le changement spectral des démodulateurs DPSK. Une approche analytique complète suivi pardes simulations numériques permettent de définir les dimensions exactes du démodulateur. Nous présentons la géométrie due démodulateur. En utilisant les paramètres obtenus, nous calculons le changement spectral avec le changement de température en utilisant notre programme informatique conçu pour observer la performance du démodulateur. Le démodulateur a été fabriqué par la société de microélectrique Canadian (CMC). La largeur de la guide d'onde du démodulateur varie de 280 nm 450 nm et la hauteur est fixe à 220 nm. Pour le démodulateur non-compensé, la largeur du guide d'onde est 450 nm. Les démodulateurs tant compensés que non-compensés sont construits sur le même fragment. Les résultats expérimentaux sont présentés et nous comparons les différentes performances du démodulateur avec et sans la technique de compensation proposée.
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Yang, Weixuan. "Temperature-dependent homogenization technique and nanoscale meshfree particle methods." Diss., University of Iowa, 2007. http://ir.uiowa.edu/etd/147.
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Covey-Crump, Elizabeth Margurite. "Temperature-dependent changes in the regulation of plant respiration." Thesis, University of York, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.423779.
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Huang, Yan. "Temperature dependent hall effect studies of GaN on sapphire /." Click to view the E-thesis via HKUTO, 2002. http://sunzi.lib.hku.hk/hkuto/record/B42577068.
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Fujita, Takahiro. "Temperature-dependent tensile and shear response of graphite/aluminum." Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/101371.
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The thermo-mechanical response of unidirectional P100 graphite fiber/6061 aluminum matrix composites (vf = 0.47) was investigated at four temperatures: -150°F, +75°F, +250°F and +500°F, using test methods developed at Virginia Tech. Two types of tests, off-axis tension and Iosipescu shear, were used to obtain the desired properties. Good experimental-theoretical correlation was obtained for Exx, vxy and G₁₂. It is shown that E₁₁ is temperature independent, but E₂₂, v₁₂ and G₁₂ generally decrease with increasing temperature. Compared with rather high longitudinal strength, very low transverse strength was obtained for the graphite/aluminum. The poor transverse strength is believed to be due to the low interfacial bond strength in this material. The strength decreases significantly with increasing temperature. The tensile response at various temperatures is greatly affected by the residual stresses caused by the mismatch in the coefficients of thermal expansion of fibers and matrix. The degradation of the aluminum matrix properties at higher temperatures has a deleterious effect on composite properties. The composite has a very low coefficient of thermal expansion in the fiber direction.M.S.
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Bonnell, Elizabeth Ann. "Temperature Dependent Behavior of Optical Loss from Hydrogen Species in Optical Fibers at High Temperature." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/78132.
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This study reports on the behavior of silica based optical fibers in a hydrogen environment at high temperatures. The hydrogen response in the form of optical loss in the wavelength range of 1000-2500 nm of a germanium doped graded index 50/125 graded index fiber was examined in the temperature range of 20–800 °C. When the fiber was exposed to hydrogen at 800 °C two absorption bands appeared: ~1390 nm assigned to the first overtone of the hydroxyl stretch and ~2200 nm band with complex assignments including the combination mode of the fundamental hydroxyl stretch with SiO4 tetrahedral vibrations and the combination mode of SiOH bend and stretch. The growth rate of the 1390 nm band fits the solution to the diffusion equation in cylindrical coordinates while the 2200 nm band does not. Absorption for both bands persisted as the fiber is cooled to room temperature. Temperature dependent behavior was observed in that as temperature increases from room temperature, the absorption intensity decreases and band shifts slightly to longer wavelengths. Temperature dependence is repeatable and reversible. However, if no hydrogen is present in the environment at temperatures greater than 700 °C, the 1390 nm band will permanently decrease in intensity, while the 2200 nm band does not change. Changes in the structure of the glass appear to be causing this temperature dependent behavior. Other necessary conditions for structural changes to cause this temperature dependent behavior are examined.Master of Science
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Mills, Robert Jeffrey. "Surface Orientation Dependent Corrosion Damage and Temperature Dependent Mechanical Property Degradation of Sensitized AA5083-H116 Alloys." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/85689.
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This study relates the sensitization process microstructural changes of 5083-H116 to its resulting corrosion resistance and mechanical performance. Alcoa 5083-H116 was sensitized in an environmental chamber at 100°C for up to ~1500 hours and 150°C up to ~2000 hours, revealing different degrees of sensitization based on exposure times. Microstructural characterization was conducted on etched sensitized samples. Additionally, samples were subjected to accelerated corrosion scenarios for subsequent microstructural examination and subsequent mechanical (tension and tensile creep) testing. To connect the laboratory studies to the field exposure, Novelis 5083-H116 was sensitized at 100°C; dog bone samples were created and exposed for two years in a beach environment to investigate possible sensitization and corrosion effects. It was found that the sensitization at 100°C and 150°C of Alcoa 5083-H116 led to recrystallization from the asreceived (AR) state of the material (3 mg/cm²). The degree of sensitization of 61 mg/cm² recrystallized the grain size the most from the AR state. The higher sensitization temperature of 150°C caused higher thickness loss and mass-loss rates (MR) for the intergranular corrosion (IGC) susceptible sensitization levels. Accelerated corrosion on different surface orientations led to different corrosion mechanisms (parallel IGC vs. perpendicular IGC). While 5083-H116 material corroded on the rolled surface led to a uniform exfoliation damage on 150°C sensitization exposure, the 100°C rolled surface only exhibited pitting corrosion damage. The through plate thickness corrosion damage, however, exhibited a corrosion susceptible-resistant-susceptible (CSRS) pattern. Mechanical properties were assessed for the various conditions in terms of room temperature tension testing and elevated temperature creep tests. Sensitization affected yield strength but did not play a role in ultimate tensile strength. The presence of corrosion damage lowered yield strength and ultimate tensile strength of the IGC susceptible sensitized 5083-H116, with the through thickness corrosion damage reducing the properties more than corrosion of the rolled surface. Material sensitized at 150°C and then corroded had a greater reduction in room temperature mechanical properties. Creep testing was performed at elevated temperatures, and it was found the solely sensitized 5083-H116 at 100°C or 150°C behaved the same as as-received 5083-H116. When corrosion damage was introduced, creep rupture times and secondary creep rates were changed. Once the corroded section area was accounted for, no significant difference in Larson-Miller parameters was observed.Ph. D.
Aluminum is frequently replacing steel in the hulls of U.S. and Australians naval ships. It is preferred because of its lower density than steel and higher corrosion resistance which reduces the need to paint topside surfaces. However, when aluminum alloys that are used in ship construction are exposed to elevated temperatures, the corrosion resistance ca be considerably decreased. Furthermore, fire resistance is always a concern on naval ships. Accordingly, we are interested in predicting how aluminum ships that may have previously corroded respond to fires. In this study, a laboratory technique was used to speed up the corrosion process of these ship hull aluminum alloys. Some samples were thermally exposed in the laboratory for microscopic analysis, corrosion testing, and subsequent mechanical testing. To connect the laboratory studies to the field exposure, thermally exposed samples were placed on a beach for two years to investigate further environmental damages. It was found that the laboratory thermal exposure weakened the aluminum alloy. The thermally exposed alloys were weakened to the corrosion process. Different surfaces of the thermally exposed plates had different corrosion damage mechanisms. Mechanical properties were assessed for the various conditions in terms of room temperature tension testing and elevated temperature creep tests. Thermal exposure affected yield strength (the ability of the material to stretch) but did not play a role in ultimate tensile strength (maximum strength prior to breaking). The presence of corrosion damage lowered yield strength and ultimate tensile strength of the corrosion susceptible thermally exposed alloy. Creep testing (constant applied stress testing) was performed at elevated temperatures (representative of fire damage scenarios), and it was found that the solely thermally exposed alloy behaved the same as as-received alloy in terms of failure mechanisms. When corrosion damage was introduced, creep rupture times (time until material fails by breaking into two pieces) was reduced. Once the corrosion damage was accounted for, mechanical properties could be more accurately represented, and failure times (conditions in the alloy needs to be replaced on ships) were predicted for the alloy.
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Lee, Sheng-Chiang. "Measurements of doping dependent microwave nonlinearities in high-temperature superconductors." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/1372.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2004.Thesis research directed by: Physics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Schildmeyer, Andrew Joseph. "Temperature and time dependent behaviors of a wood-polypropylene composite." Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/Summer2006/a%5Fschildmeyer%5F072006.pdf.
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Robert, Kylie Anne. "Temperature-dependent sex determination in the viviparous lizard Eulamprus tympanum." University of Sydney. Biological Science, 2003. http://hdl.handle.net/2123/557.
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Abstract There are a remarkable variety of sex determination systems among different animal taxa. In most animals, sex is determined chromosomally. Although in an increasing number of animals sex determination has been found to be influenced primarily by the environment. Species with genotypic sex determination (GSD) have their sex determined at the time of fertilization, by genetic factors alone and those with environmental sex determination (ESD) have their sex determined by environmental factors that act after fertilization. Temperature-dependent Sex Determination (TSD), whereby the sex of the developing embryos depends on the temperature at which they develop is widespread in oviparous reptiles and occurs in all crocodilians, marine turtles and tuatara examined to date and is common in many freshwater turtles and lizards. SECTION ONE Temperature-dependent sex determination (TSD) was never expected to occur in viviparous reptiles, as thermoregulation by pregnant females would result in relatively stable gestation temperatures. Temperature-dependent sex determination and viviparity goes against all the basic assumptions that TSD occurs in oviparous reptiles where temperatures within a nest vary widely. However, skewed sex ratios as a result of incubation temperature indicated the possibility of TSD in the viviparous lizard Eulamprus tympanum. In my first experiments I show the first recorded case of a viviparous reptile with TSD. The developing embryos of the viviparous skink E. tympanum are subject to TSD, with gestation temperature having a highly significant effect on sex and warmer temperatures giving rise to male offspring (Chapter 1). Sex is fully determined at the time of birth and can be differentiated histologically into testes or ovaries (Chapter 2). The morphology and histological characteristics of the gonads of neonatal E. tympanum resulting from the treatment temperatures described in chapter 1 illustrate that sex in E. tympanum is easily distinguished at the time of birth and corresponds with the presence or absence of hemipenes. Males are histologically characterised by an elongated gonad consisting of seminiferous tubules with either no cortical epithelium or, if present at all, in a very thin band. If they are present, M�llerian ducts, showing signs of degeneration, are attached to the kidney by a shortened mesosalpinx. Females are histologically characterised by an irregularly shaped gonad consisting of a thick cortical epithelium that occasionally contains oocytes. The M�llerian ducts are obvious structures attached to the kidney by a fibrous mesosalpinx. The presence or absence of hemipenes is a reliable technique for determining sex in newborn E. tympanum. Sex determination is easiest to perform on neonates within the first few days of birth as hemipenes become increasingly difficult to evert as neonates age, however, with practice they are easily identified without full eversion. SECTION TWO The thermal biology of E. tympanum in the field is restricted by both the thermal properties of their habitat (Chapter 3) and behavioural modifications when faced with a predation threat (Chapter 4). The available temperatures in the field suggest that TSD is biologically relevant in the species and not just a laboratory artefact; E. tympanum can attain mean selected temperatures achieved in the laboratory but the proportion of time at the temperature is restricted. Females actively thermoregulate in the field, although they are restricted in their efficiency of thermoregulation by environmental constraints, for example, microhabitat structure, weather conditions, predator avoidance and social ranking. The highly territorial nature and high densities of E. tympanum present in Kanangra Boyd National Park potentially force less dominant individuals into less favourable habitats that are significantly cooler. An important point is that gravid females in more favourable habitats in the period encompassing the middle third of development (the assumed sex determining period) are selecting higher temperatures, with lower variance and have greater thermoregulatory efficiency than during the rest of pregnancy, therefore, thermoregulating more precisely during this thermosensitive period (Chapter 3). Chemosensory cues provide important information on the risk of predation. Hence, chemoreception is a common mechanism used by many species to detect the presence of, and subsequently respond to, a potential predator. The perceived risk of predation may force retreat to sub-optimal conditions, forcing a trade-off between the risk of predation and the ability to acquire resources. The basking regime maintained by gravid female E. tympanum, can directly alter sex ratios of offspring produced through temperature-dependent sex determination (Chapter 1). The avoidance of predator scents may restrict basking ability and in turn alter the sex of offspring produced. I measured responsiveness to chemical cues using tongue flicks as an indicator of chemical discrimination in females of different reproductive condition. I then measured activity and basking behaviour of gravid and non-gravid females in experimental enclosures in the presence of various chemical stimuli to determine if basking opportunity is compromised by the presence of a predator scent. Females respond differently depending upon reproductive condition, with gravid females responding most significantly to a predator scent. Activity, basking frequency, and time spent in the open (basking duration) are significantly reduced in gravid females in the presence of a predator stimulus. Under laboratory conditions, gravid females modify their behaviour and forego the opportunity to bask when there is a perceived predation risk (Chapter 4). SECTION THREE As female viviparous reptiles can regulate the temperature of the embryo by maternal temperature selection (Chapter 1), the occurrence of TSD in E. tympanum opens the possibility for females to select the sex of offspring. Reproducing females may benefit by facultatively adjusting their investment into sons over daughters or vice versa, in response to population wide shifts in adult sex ratios. Female E. tympanum, can manipulate the sex of their offspring in response to sex imbalances in the population using temperature-dependent sex determination (Chapter 5). When adult males are scarce, females produce male-biased litters and when adult males are common, females produce female-biased litters. The cues used by a female to assess the adult population are not known, but presumably depends upon the female�s experience throughout the breeding season and is the subject of further investigation (Chapter 6). The maternal manipulation of offspring sex ratio in E. tympanum suggests a selective advantage of temperature-dependent sex determination. Any facultative sex ratio response needs to recognise the scarcity of one sex in order to overproduce that sex in the next generation; offspring sex ratio will vary inversely with adult sex ratio. Maternal sex allocation in E. tympanum is linked with population (or adult) sex ratio (Chapter 5), and one of the mechanisms by which females recognise an imbalance may be linked to visual recognition of males (Chapter 6). Females maintained throughout pregnancy without any male stimulus produce entirely male offspring (Chapter 5). In contrast females exposed to male stimulus produce both sexes (Chapter 5). Females respond differently to varying degrees of male stimulus and visual recognition of males in a population may be more important than chemoreception. In the absence of visual cues, females produce more male offspring, even when chemosensory cues are present (Chapter 6). The study system presented here offers many advantages over oviparous species with TSD, due to E. tympanum being relatively short lived and fast maturing. Thus, the fitness consequences over multiple generations as a result of gestation can be investigated. Viviparity allows maternal control of embryonic temperature during gestation and a means of maternal sex allocation. Until now the maternal side of TSD and sex allocation has been where the mother deposits her eggs and the allocation of sex steroid hormones at oviposition, both of which have been difficult to study. The work presented and the study system itself should inspire great interest in TSD and viviparous reptiles.
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Li, Jing Adela, and 李晶. "Temperature-dependent toxic effects of selected chemicals on marine organisms." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/211051.
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Anthropogenically driven climate change not only results in rising of sea temperature but also leads to more frequent and longer-lasting cold and heat waves. Meanwhile, coastal marine ecosystems are constantly challenged by increasing threats of chemical pollution. Temperature and chemical stressors can jointly affect the livelihood of marine organisms, but their combined effects are still poorly understood. Therefore, this study aimed to investigate the effects of thermal stress and chemical exposure on the marine medaka Oryzias melastigma, copepod Tigriopus japonicus and rotifer Brachionus koreanus. The four selected chemical contaminants included copper sulphate pentahydrate (Cu), dichlorophenyltrichloroethane (DDT), triphenyltin chloride and copper pyrithione. It was hypothesized that marine organisms are more susceptible to chemical exposure at both cold and warm extremes.
In vivo acute ecotoxicity tests were conducted over a wide temperature range to ascertain the relationship between thermal stress and chemical toxicity. For O. melastigma larvae, the lowest toxicity occurred at an optimum temperature range; the chemical toxicity further increased with temperature increase or decrease from this optimum, and exacerbated at extremely low and high temperatures. For T. japonicus and B. koreanus, the chemical toxicity generally increased with increasing temperature. Such inter-species dissimilarities were possibly due to differences in the uptake route, detoxification mechanism, avoidance behaviour and physiological response between the fish and the copepod or rotifer.
Experiments were conducted to evaluate the temperature-dependent physiological and biochemical responses, and thermal tolerance of O. melastigma larvae. The growth in the fish larvae showed an inverse and negatively skewed V-shape relationship with temperature, with a significant reduction in performance at both low and high thermal extremes. A mismatch between demand and supply of oxygen and energy under extremely cold and warm conditions was probably the primary cause of growth inhibition and metabolic impairment, leading to a temporary adaptation by a shift to anaerobiosis and an induction of heat shock proteins (HSPs).
Temperatures at both cold and warm extremes increased toxicities of DDT and Cu to O. melastigma larvae, resulting in restricted growth and interrupted oxygen consumption rate. The fish larvae modulated their metabolic pathway and produced stress proteins (i.e., HSPs and metallothioneins) for adaptation to the combined stress. However, such responses were disrupted by combinations of thermal extremes, in particular high temperature, and high chemical concentration. Most importantly, both DDT and Cu exposure significantly reduced the thermal tolerance of the fish larvae.
The interacting effect of temperature and Cu was also investigated on T. japonicus. The results showed that their combined effect could significantly reduce the survival, lengthen the developmental time and change the sex ratio of the copepod. Transcriptions of several stress-related genes (i.e., glutathione reductase, glutathione S-transferases and HSPs) in the adult T. japonicus were significantly affected by the joint-effect of temperature and Cu exposure, implying that these genes played essential roles in protecting the cellular integrity against the stresses.
This study advanced the understanding on the temperature-dependent toxicity of chemical contaminants to marine organisms, and provided valuable information and empirical models for deriving water quality criteria of chemical contaminants at various temperatures.published_or_final_version
Biological Sciences
Doctoral
Doctor of Philosophy
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Dodd, Keela L. "The molecular biology of temperature-dependent sex determination in reptiles." Birmingham, Ala. : University of Alabama at Birmingham, 2007. https://www.mhsl.uab.edu/dt/2008r/dodd.pdf.
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Thesis (Ph. D.)--University of Alabama at Birmingham, 2007.Additional advisors: Asim Bej, Gene Hines, Douglas Watson, Douglas Weigent. Description based on contents viewed Oct. 2, 2008; title from PDF t.p. Includes bibliographical references.
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Robert, Kylie. "Temperature-dependent sex determination in the viviparous lizard, Eulamprus tympanum." Connect to full text, 2003. http://hdl.handle.net/2123/557.
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Thesis (Ph. D.)--University of Sydney, 2004.Title from title screen (viewed 5 May 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Biological Sciences, Faculty of Science. Degree awarded 2004; thesis submitted 2003. Appendices contains published articles co-authored by Robert. Includes bibliographical references. Also available in print form.
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Peuravaara, P. (Petri). "Temperature-dependent chemical shift in the aqueous solution of xenon." Master's thesis, University of Oulu, 2017. http://urn.fi/URN:NBN:fi:oulu-201705232035.
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At standard pressure, the chemical shift of Xe-129 in an aqueous solution of xenon exhibits a maximum as a function of temperature at 311 K, which is in contrast to the well-known density maximum of water at 277 K. In the present work, this phenomenon is studied by means of a molecular dynamics simulation, where the xenon chemical shift is computed quantum-chemically for snapshots of the simulation trajectory. Also, a simple semianalytical model is developed in which the water around the xenon atom is interpreted to form a shell of uniform density. Both approaches are found to be able to qualitatively reproduce the maximum. In addition, the chemical shift in the semianalytical model is seen to result as a product of the local water density around the xenon and a term corresponding to the xenon-water collision energetics. The latter term can be seen to shift the location of the maximum up in temperature, as compared to the temperature of maximum density.
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Ndaba, Cynthia Reitumetse. "Entropy analysis in a channel flow with temperature dependent viscosity." Thesis, University of Limpopo (Turfloop Campus), 2007. http://hdl.handle.net/10386/956.
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Thesis (M.Sc. (Applied Mathematics)) --University of Limpopo, 2007The thermodynamic irreversibility in any fluid flow process can be quantified through entropy analysis. The first law of thermodynamics is simply an expression of the conservation of energy principle. The second law of thermodynamics states that all real processes are irreversible. Entropy generation is a measure of the account of irreversibility associated with the real processes. As entropy generation takes place, the quality of energy (i.e. exergy) decreases. In order to preserve the quality of energy in a fluid flow process or at least to reduce the entropy generation, it is important to study the distribution of the entropy generation within the fluid volume. In this dissertation, the inherent irreversibility in the flow of a variable viscosity fluid in both a closed channel and an open channel is investigated. The channel is assumed to be narrow, so that the lubrication approximation may be applied and the fluid viscosity is assumed to vary linearly with temperature. Both the lower and the upper surfaces of the channel are maintained at different temperature. The simplified form of governing equations is obtained and solved analytically using a perturbation technique. Expressions for fluid velocity and temperature are derived which essentially expedite to obtain expressions for volumetric entropy generation numbers, irreversibility distribution ratio and the Bejan number in the flow field. In chapter 1, a historic background of the study is highlighted. Both closed and open channels problem are investigated in chapters 2 and 3. In chapter 4, generally discussion on the overall results obtained from the investigation is displayed together with possible areas of future research work.
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Van, Sickle Austin Reed. "Temperature Dependent Optical Properties of Silicon Quantum Dot/Polymer Nanocomposites." Thesis, North Dakota State University, 2012. https://hdl.handle.net/10365/26619.
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The photoluminescent properties of silicon quantum dots embedded in a stabilizing polymer matrix are relevant to a number of potential applications of these unique nanomaterials such as drug delivery, temperature sensing, and photovoltaics. Aspects of how these photoluminescent properties change with respect to variations in such parameters as excitation intensity, polymer interactions, particle size and particle polydispersity are investigated here. Improving the photostability and understanding the nature of how this is achieved will be critical for realizing the potential of silicon quantum dots in a number of applications. Improvements in photoluminescent stability related to fluorescence intermittency, radiative lifetime, emitted intensity, and wavelength shifts are shown to be due to decreased exposure to oxygen, increased particle packing, decreased temperature, and increased monodispersity of the quantum dots.
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Zhao, Lu. "Temperature-dependent Regulation of Sugar Metabolism During Cold Stress Responses." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1483361544085616.
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Hirsch, Michael Robert. "Temperature dependent fretting damage modeling of AISI 301 stainless steel." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/52975.
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Prediction of fatigue damage due to fretting is complex due to the number of influential factors and the competitive interaction between wear and fatigue. The majority of current fretting damage modeling approaches are limited to narrow ranges of conditions where little competition between damage mechanisms occurs. Recent models which account for damage interaction are largely phenomenological in nature and are still limited to a narrow range of applicability. A method to characterize and model the level of fatigue damage due to fretting was developed in this work to address the shortcomings of the current methods available by extending the range of conditions captured and enhancing the physical basis of the damage model.
Baseline material properties for thin sheets of AISI 301 stainless steel in the full hard condition were determined as a function of temperature through tensile tests, fatigue tests, and metallography. Fretting experiments were performed for contact between 301 stainless steel and each ANSI A356 aluminum and AISI 52100 steel. Fretting experiments were performed over a range of material combinations, normal forces, displacement amplitudes, atmospheres, and temperatures. Subsequent characterization of the damage due to fretting was performed to determine the level of wear and fatigue damage incurred for each condition tested.
A finite element model of the experiment was created to determine the cyclic stress-strain behavior and local frictional energy dissipation for each condition. Fatigue damage metrics were evaluated to determine the effects of the contact conditions on the driver for fatigue damage. A new model for fatigue damage due to fretting was developed which incorporates the wear behavior to describe the effect of wear on the level of fatigue damage caused by fretting. The level of fatigue damage is influenced using a function of frictional energy dissipation and wear rate to account for differences in wear mechanisms and changes in the severity of wear caused by changes in oxidation behavior and mechanical properties which result from changes in temperature or contacting materials.
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Smith, Daniel J. "Rapid determination of temperature-dependent parameters for the crystal viscoplasticity model." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/43670.
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Thermomechanical fatigue life prediction is important in the design of Ni-base superalloy components in gas turbine engines and requires a stress-strain analysis for accurate results. Crystal viscoplasticity models are an ideal tool for this stress-strain analysis of Ni-base superalloys as they can capture not only the anomalous yielding behavior, but also the non-Schmid effect, the strain rate dependence, and the temperature dependence of typically large grained directionally-solidified and single crystal alloys. However, the model is difficult to calibrate even for isothermal conditions because of the interdependencies between parameters meant to capture different but similar phenomena at different length scales, many tied to a particular slip system. The need for the capacity to predict the material response over a large temperature range, which is critical for the simulation of hot section gas turbine components, causes the determination of parameters to be even more difficult since some parameters are highly temperature dependent. Rapid parameter determination techniques are therefore needed for temperature-dependent parameterizations so that the effort needed to calibrate the model is reduced to a reasonable level.
Specific parameter determination protocols are established for a crystal viscoplasticity model implemented in ABAQUS through a user material subroutine. Parameters are grouped to reduce interdependencies and a hierarchical path through the groups and the parameters within each group is established. This dual level hierarchy creates a logical path for parameter determination which further reduces the interdependencies between parameters, allowing for rapid parameter determination.
Next, experiments and protocols are established to rapidly provide data for calibration of the temperature-dependencies of the viscoplasticity. The amount of data needed to calibrate the crystal viscoplasticity model over a wide temperature range is excessively large due to the number of parameters that it contains which causes the amount of time spent in the experimentation phase of parameter determination to be excessively large. To avoid this lengthy experimentation phase each experiment is designed to contain as much relevant data as possible. This is accomplished through the inclusion of multiple strain rates in each experiment with strain ranges sufficiently large to clearly capture the inelastic response.
The experimental and parameter determination protocols were exercised by calibrating the model to the directionally-solidified Ni-bas superalloy DS-CM247LC. The resulting calibration describes the material's behavior in multiple loading orientations and over a wide temperature range of 20 °C to 1050 °C. Several parametric studies illustrate the utility of the calibrated model.
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Maw, Toby. "The temperature dependent phases of some 3d transition element Heusler alloys." Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/9641.
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The full characterisation of the compound series Cr2VX (X = Al, Si, Ga, Ge) is reported. X-ray and neutron diffraction measurements were performed along with electrical resistivity and magnetisation measurements on each compound. It is found that Cr2VAl crystallises in the disordered Heusler A2 structure with space group Im3 ̅m and this structure remains stable between 5K and 1223K. Contrary to this, the other compounds in the series crystallise in a partially ordered A15 structure with space group Pm3 ̅n. These compounds are shown to behave more like pseudo binary systems of composition X3Y such as Cr3X and V3X than Heusler systems of composition X2YZ. Each compound acts metallically and has magnetic properties consistent with those of weak Pauli paramagnetic materials. It is suggested that the size of the unit cell is the dominant factor for these compounds whether they crystallise into either the A2 or the A15 structure. This is investigated with the high temperature characterisation of the compound series Cr2VGa1-xAlx (x = 0, 0.25, 0.5, 1). Structural phase transformations are identified and characterised using a combination of high temperature neutron diffraction and electrical resistivity measurements. The results of these measurements show that the phase transformations involve displacive, order disorder and diffusion based processes. Furthermore, they reveal the existence of a metastable intermediate phase with a tetragonal unit cell and space group P4 ̅2c. The compound series Cr2-xFexVAl (x = 0, 0.5, 1.5, 2) was investigated to better understand the nature of the magnetic properties observed within this group of alloys. The magnetisation of each compound was measured with a SQUID magnetometer. At high temperature, weak Pauli paramagnetic behaviour retained for each compound. However, at low temperature an up-turn can be seen in the magnetisation of the compounds containing Fe such that their susceptibility has a logarithmic relationship with temperature. Neutron diffraction measurements show that the Fe rich and Cr rich compounds form the ordered L21 and disordered A2 Heusler structures, respectively. However, no evidence was found of a structural change at low temperatures to activate the change in magnetic response. Finally, the structural ordering of the compound series Ni2-xMn1+xGa is explored using high temperature electrical resistivity measurements. Increasing Mn content is shown to decrease the order disorder transition temperatures due to increased levels of atomic disorder. This affects a sample s state of atomic order after heat treatment, which is usually performed by quenching samples from 800ºC. Therefore, it is an important influence on the compound s reported magnetic and martensitic transitions particularly for Mn rich samples.
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Jumani, Sajit Satish. "An Invertible Open-Loop Nonlinear Dynamic Temperature Dependent MR Damper Model." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/32664.
Full textAbstract:
A Magnetorheological damper is a commonly used component in semi-active suspensions that achieves a high force capacity and better performance than a passive system, without the added expense and power draw of a fully active system, all while maintaining failsafe performance. To fully exploit the capabilities of an MR Damper, a high fidelity controller is required that is simple and easy to implement, yet does not compromise the accuracy or precision needed in many high-performance applications. There is a growing need for this level of operation, and this proposed work addresses these requirements by creating an empirically derived invertible model that enables the development of more accurate command signals by capturing the effect of temperature on a MR Damperâ s performance capabilities. Furthermore, this solution is specifically tailored for real-time application and does not require force feedback. Thus it requires low computation power and minimizes end-user cost by eliminating the need for additional high cost sensors such as load cells. A notable observation that resulted from the development of this proposed model was the difference in behavior between on and off states. Additionally a unique behavior was recognized with respect to the transition between high speed and low speed damping. For validation, the proposed model was compared against experimental data as well as an industry standard Spencer model; it produced excellent results in both cases with minimal error.Master of Science
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Bulmer, John Simmons. "Temperature and Frequency Dependent Conduction Mechanisms Within Bulk Carbon Nanotube Materials." Wright State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=wright1290546481.
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Wei, Yahan. "Iron- and Temperature-Dependent Regulation of Shigella Dysenteriae Virulence-Associated Factors." Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1478519844517268.
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Leyva-Ramos, Elisa. "The temperature dependent photochemistry of aryl azides and aryl diazo compounds /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487267024997622.
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Brandt, Josef. "Temperature Dependent Size Exclusion Chromatography for Investigating Thermoreversibly Bonding Polymer Systems." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-207589.
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Polymers capable of thermally controlled reversible bonding reactions are promising candidates for stimuli responsive materials, as required for self-healing or drug delivery materials. In order to investigate how the dynamic reactions can be controlled, effective analytical tools are demanded that are capable of analyzing not only the polymers but can also monitor the respective bonding reactions. Herein, we employ size exclusion chromatography in a newly developed temperature dependent mode (TD SEC) for the in situ characterization of polymers that undergo retro Diels-Alder (rDA) reaction at temperatures higher than 60 °C. Monitoring the evolution of the molar mass distribution of the polymers during the rDA reaction and evaluating the data quantitatively gives detailed information about the extent of the reaction and allows elucidating structural parameters that can be used for controlling the polymers debonding behavior.
In contrast to spectroscopic techniques, TD SEC analyzes only the size of the polymers, hence the polymers do not need to fulfill any particular requirements (e.g. presence of detectable functional groups) but only need to be soluble in the TD SEC, which makes the method universally applicable. Side effects that might bias the results are minimized by using a high temperature chromatograph that allows performing the analysis in a broad temperature range (60 – 200 °C) and in different solvents. Thus, the analysis can be performed under the exact conditions that are required for the bonding reactions and an in situ image is provided.
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Emer, Sherri Ann. "Temperature-Dependent Sex Determination in Manouria Emys Emys, The Asian Forest Tortoise." Digital Archive @ GSU, 2007. http://digitalarchive.gsu.edu/biology_theses/11.
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Captive husbandry programs in zoos have documented nesting behavior and have successfully hatched Manouria emys emys, but data on sex determining mechanisms and sex ratios are absent. A total of 30 M. e. emys eggs were artificially incubated at five different temperatures in constant humidity. Mean incubator temperatures were 24.99°C, 25.06°C, 27.18°C, 28.00°C, and 30.79°C. Incubation duration ranged from 60 days to 92 days, and hatching success was 50%. Sex determined by histology and laparoscopy resulted in male differentiation at low temperatures (24.99°C, 27.18°C) and female differentiation at high temperatures (30.79°C). Pivotal temperature was estimated to be 29.29°C. The following investigation into temperature-dependent sex determination (TSD), including its presence or absence, pattern, and pivotal temperature, has implications for studies of adaptive significance of reproductive behaviors and of chelonian phylogenetic history. Additionally, the proposed study can provide foundations for conservation management decisions, and for captive breeding programs.
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Speriatu, Lucian M. "Temperature dependent mechanical properties of composite materials and uncertainties in experimental measurements." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0011370.
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Yeom, Sin Hea. "TEMPERATURE-DEPENDENT TUNABLE PHOTOLUMINESCENCE PROPERTIES OF CARBON NANODOTS DERIVED FROM POLYETHYLENE GLYCOL." UKnowledge, 2014. http://uknowledge.uky.edu/chemistry_etds/46.
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Fluorescent carbon dots (C-dots) are well known for their low cell-cytotoxicity, biocompatibility, low preparation cost, excitation dependent photoluminescence, and excellent photostability. Typically, raw C-dots have low quantum efficiency and thus researchers have been utilizing biocompatible polymers such as polyethylene glycol (PEG) as a passivation agent in order to increase fluorescence signal. In this work, we report fluorescent self-passivated carbon nanodots (CNDs) synthesized from PEG by using it as a carbon source as well as a passivating agent. Importantly, the addition of graphene quantum dots (GQDs) during the synthesis of self-passivated CNDs can tune photoluminescence property. The results of bioimaging and cytotoxicity test of self-passivated CNDs hold promises for biomedicine applications.
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Zheng, Li. "Temperature-dependent visco-elastic-plastic analysis of permanent deformation in bituminous pavements." Thesis, London South Bank University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259911.
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In this project the deformation behaviour of a rolled asphalt mixture is investigated, and the influence of temperature on the deformation mechanism of the mixture is assessed, based on a series of uniaxial creep and creep recovery experiments conducted under compressive stress and controlled temperature. Firstly, the experiments were conducted for various temperature levels, loading time, and number of load applications. It is found that the total strain consists of the elastic, plastic, viscoelastic and viscoplastic strain components. The temperature and number of load cycles hardly affects the elastic strain, but the plastic increases with temperature and decreases with number of load applications at constant stress levels. The timedependent (viscoelastic and viscoplastic) and the instant (elastic and plastic) deformation reduced respectively to viscoelastic and elastic deformation components at low temperature. Secondly the relationship between the total strain and the variables, time, temperature, stress and number of cycles are successfully modelled mathematically. After this, the model is introduced into the finite element method. Also an approximate approach for permanent deformation in a flexible pavement is presented and a non-linear finite element program "CEPVP" with consideration of the pavement temperature profile was devised. The calculation was conducted using program `CVEVP". It was found that there was a great agreement between the computation and the test. Finally, a general comparison of program 'CVEVP' and package ANSYS was conducted. Considering the effects of mechanical parameters of bituminous materials, time of loading, thickness of asphalt and granular layers and environmental temperature, calculation of permanent deformation of bituminous pavement was carried out using program `CVEVP'. Some findings were concluded. For example, it was found that the plastic properties of asphalt mixture are the important factor in calculating the permanent deformation of flexible pavements, particularly at the upper end of the temperature spectrum.
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Wheeler, Jeanette. "Temperature-dependent butterfly dynamics." Master's thesis, 2010. http://hdl.handle.net/10048/1546.
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Climate change is currently a central problem in ecology, with far-reaching effects on species that may be diffcult to quantify. Ectothermic species which rely on environmental cues to complete successive stages of their life history are especially sensitive to temperature changes and so are good indicators of the impacts of climate change on ecosystems. Based on data collected in growth experiments for the alpine butterfly Parnassius smintheus (Rocky Mountain Apollo), a novel mathematical model is presented to study developmental rate in larval insects. The movement of an individual through larval instars is treated as a discrete-time four-outcome Bernoulli process, where class transition and death are assigned temperature-dependent probabilities. Transition and mortality probabilities are estimated using maximum likelihood estimation techniques. This adult emergence model is then integrated into a reproductive success model, and multi-year implications of climate change on the population dynamics of P. smintheus are explored.Applied Mathematics
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Yu-ChunChiu and 邱宇君. "Temperature-dependent magnetic organic semiconductors." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/d642gp.
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碩士國立成功大學
光電科學與工程學系
105
Magnetic organic semiconductor thin films composed of pentacene molecules and Ni atoms were fabricated via molecular beam epitaxy and electron beam deposition under different deposition temperatures. When deposition temperature was increased, pentacene molecules and Ni atoms could obtain sufficient kinetic energy, facilitating Ni atoms to be at preferable positions among pentacene molecules. Through Raman spectroscopy analyses of Ni-doped pentacene films, we observed the existence of electronic coupling between the 2p orbital of pentacene molecules and 3d orbital of Ni atoms. Furthermore, the electronic coupling would be enhanced strongly after applied an external magnetic field to the Ni-doped pentacene film. The topographies of different pentacene films, which could be observed from atomic force microscopy (AFM), were dissimilar. Magnetic properties of Ni-doped pentacene films were examined via magnetic-field-dependent magnetization, M-H, at the room temperature. The models of magnetic transition, magnetic transmission bridge, were proposed to explain the remnant magnetization of the magnetic organic semiconductor thin film.
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Lin, Kun-Zheng, and 林坤政. "Temperature-dependent Raman scattering of ZnSeO." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/65299621851060405488.
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碩士國立中央大學
物理學系
101
The oxygen concentrations of ZnSe1-xOx alloys studied in this thesis are in the range of 1.5%x11.6%. Because of the limited oxygen solubility, Nabetani had proposed that ZnSeO alloy composition up to 6.4%. Our highest concentration up to 11.6%.In our previous study indicate the results of photoluminescence (PL) indicate that the relationship between band gap and oxygen composition can be well described in the framework of band anti-crossing model (BAC model). However, the full width of half maxima (FWHM) of signals becomes broader and the intensities become weaker in the higher O concentration range. These results indicate that the crystal structures may have changed. Thus we investigated the crystal structure via Raman spectrum. In 10K Raman scattering experiments, the phonon frequency is influenced by strain and effective mass. With ZnSe mixes O, the phonon frequency become slower than ZnSe, but when oxygen concentration higher than 9.3%, the frequency is dominated by effective mass. The phonon frequency becomes faster. In temperature-dependent Raman scattering, we can find as the oxygen concentration increases, the anharmonic effect will increase. Besides, the FWHM of LOZnSe becomes broader than ZnSe. In the end, we will discuss optical phonon life time. When increasing the oxygen concentration, the life time will become shorter than ZnSe.
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Huang, Chiyi, and 黃繼億. "Temperature Dependent Photorefractive Properties of BaTiO3." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/38699030082241633952.
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Chen, Ming Chung, and 陳明聰. "Temperature-dependent Optical Properties in BaTiO3." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/04350186823093495271.
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碩士中原大學
物理學系
87
Photorefractive crystals have emerged as the best candidate for storing large amount of optical image information. According to the Band Transport model, photorefraction results from absorption at impurity level inside crystals. Thus an understanding of impurity levels within a photorefractive crystal will facilitate further optimization of imputity doping as well as further understanding of photorefraction. However, at room temperature most impurity levels are broadband and may overlap with another impurity level spectrum. Thus it requires lowering he temperature in order to separate each individual impurity absorption spectrum. The purpose of this investigation is to study absorption spectroscopy and photorefractive effect for BaTiO3 at low temperature. As we will show later that lowest temperature that we were able to acquire absorption spectra was too high to produce sufficient narrow-band spectra. However, we did discover accidentally another temperature-dependent effect for extraordinary refractive index in BaTiO3. The main obstacle for obtaining low temperature absorption spectra was that we were unable to prevent the crystal to become multiple domains during the cooling down process. This in turn was due to the fact that there is a phase transition, which should take place at 278K. Based on our observation(using its optical transmission as a criteria) the transition tool place at about 255K. This reduction of phase transition temperature has provided us with sufficient temperature window to investigate temperature-dependent two-wave mixing phenomenon. The results reveal that the lower the temperature was the longer it took to remove gratings. We suggest that this fact may be due to the reduction of thermal excitation of carriers. Its exact mechanism, however, requires further investigation. A very interesting result in this study is that the extraordinary index in BaTiO3 is highly sensitive to the temperature variation. Although the temperature-induced grating may eventually disappear as temperature become stable, the fact that the incident beam often become a heating source by itself suggests that we may have to include the impact of temperature-induced grating in considering the effect for photorefractive gratings in BaTiO3 , especially, in the transient regime.
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Cho, Yun-Ting, and 卓筠庭. "Temperature dependent photodesorption of CO ices." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/95572r.
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碩士國立中央大學
物理學系
107
Vacuum ultraviolet (VUV) photon induced non-thermal desorption of solid phase molecules has been applied to explain the massive amount of gas phase CO in cold dense clouds and in the interstellar region. According to previous studies, the photodesorption yield decreases with higher deposition temperatures. Muñoz Caro et al. (2016) tried to explain the change in the photodesorption yield by the structure and spontelectric field of CO ices. However, their results indicate that there are also other physical properties that affect the variation of the photodesorption yield with the deposition temperature. VUV induced photodesorption of CO ices is described as due to desorption induced by electronic transition, which is desorption caused by the transfer of energy from excited molecules to surface molecules. However, the model does not contain a detailed description of how energy transfer in CO ices occurs. In this work, we introduce an absorption cross section of CO ices, and examine how the energy amplitude and energy transfer depth vary as a function of the deposition temperature, to explain the effect of the deposition temperature on the photodesorption yield of CO ices.
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Yen, Shih-Chiang, and 顏世強. "Temperature dependent Photoluminescence spectrum of ZnO." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/00070505091034578831.
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Lin, Sung-I., and 林松毅. "Temperature-dependent photoluminescence of InAs quantum dots." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/57284173444943442937.
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Abozaid, Hesham. "Temperature Dependent Sex Determination In Zebrafish (Danio rerio)." Thesis, 2012. http://hdl.handle.net/11858/00-1735-0000-0006-AB49-9.
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Li, Yen-Chi, and 李彥其. "Temperature-dependent Hall measurement on undoped GaN epilayer." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/98405530657372519600.
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碩士國立中山大學
物理學系研究所
92
The temperature-dependent Hall measurement was performed on the undoped GaN thin films grown by molecular beam epitaxy. The mobility and electron density were obtained by the T-dependent ( 4.2K~300K ) Hall measurement at magnetic field 300mT. Since the Hall coefficient is the ratio of the perpendicular electric field to the product of current density and magnetic field, we calculate the mobility and electron density to get the temperature-dependent mobility and electron density curves. We change the N/Ga ratio on the epilayer of two samples and analysis the mobility and carrier density against temperature. The sample growth procedure were (1)nitridation for 60 min, with ,at .(2) low temperature GaN buffer layer growth for 2 min, with ,at , and (3)high temperature GaN epilayer growth for 3hr, at . The N/Ga ratio of the samples are 30 and 35.
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Wang, Bin. "MEMS-based temperature-dependent characterization of biomolecular interactions." Thesis, 2012. https://doi.org/10.7916/D8J390NZ.
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Biomolecular interactions are of fundamental importance for a wide variety of biological processes. Temperature dependence is a ubiquitous effect for biomolecular interactions as most biological processes are thermally active. Understanding the temperature dependence of biomolecular interactions is hence critical for a wide variety of applications in fundamental sciences and drug discovery and biotherapeutics. Micro-Electro-Mechanical Systems (MEMS) technology holds great potential in facilitating temperature-dependent characterization of biomolecular interactions by providing on-chip microfluidic handling with drastically reduced sample consumption, and well-controlled micro- or nanoscale environments in which biomolecules are effectively manipulated and analyzed. This thesis is focused on various MEMS-based devices for temperature-dependent characterization of biomolecular interactions. Biomolecular interactions can occur with biomolecules in solution or with either the target or receptor molecules immobilized to a solid surface. For surface-based biomolecular interactions, we first present microcantilever-based characterization of biomolecular affinity binding with in-situ temperature sensing, using a demonstrative system of platelet-derived growth factor (PDGF) and an inhibitory ligand. The temperature-dependent kinetic and equilibrium binding properties are determined. In addition, a microfluidic approach for temperature-dependent biomolecular behavior with single-molecule resolution is also presented. Using a platform that combines microfludic sample handling, on-chip temperature control, and total internal reflection fluorescence (TIRF) microscopy, we have studied the temperature dependence of the structural dynamics of transfer RNA (tRNA) translocation through ribosome in protein synthesis. For solution-based biomolecular interactions, we mainly focus on calorimetry, a technology that directly measures heat evolved in biological processes. We first present a MEMS differential scanning calorimetric (DSC) sensor integrating highly sensitive thermoelectric sensing and microfluidic handling for thermodynamic characterization of biomolecules. We have characterized the unfolding of protein (e.g. lysozyme) at minimized sample consumption with thermodynamic properties determined, including the specific heat capacity, molar enthalpy change, and melting temperature. In addition, we also present the development of a variant of standard DSC, temperature-modulated DSC (AC-DSC), on a MEMS device for thermodynamic characterization of biomolecules. Preliminary results again with lysozyme unfolding at optimum modulation frequencies have been presented with thermodynamic properties determined. Furthermore, we have developed a MEMS isothermal titration calorimeter (ITC) integrating thermally isolated calorimetric chambers, on-chip passive mixing, and environmental temperature control, for temperature-dependent characterization of biomolecular interactions. We have characterized the interactions of 18-Crown-6 and barium chloride, as well as ribonuclease A and cytidine 2'-monophosphate, in a 1-µL volume with low concentrations (ca. 2 mM). Thermodynamic properties, including the stoichiometry, equilibrium binding constant, and enthalpy change, are also determined.
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Yu, Tsu-Hsiang, and 喻祖祥. "Disorder Dependent Debye Temperature in Al100-xTix Alloy." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/60066473564670278666.
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碩士國立交通大學
電子物理系所
100
We have prepared a series of disorder system sample which are Al100-xTix bulks with x varying from 0 to 5 by a standard arc-melting method. The resistivities of these bulks were measured from 10 to 500 K. The room temperature resistivities for our samples vary from 2.7 cm (pure) to 4.7 cm (5% doped). Comparing our measured results with Bloch-Grüneisen and electron-phonon-impurity interference theories, we have extracted Debye temperature from 425 down to 364 K. The measured resistances are well described by the Bloch-Grüneisen law between 100 and 500 K. In low temperature regime, leading to disordered, the electron-phonon-impurity interference effect contributes significantly to the measured resistivities.