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- Creators: Barrett, The Honors College
Description
This thesis is a qualitative research study that focuses on siblings of children with Autistic Spectrum Disorder (ASD). Even though it is expected that having a child with ASD in the family will influence the whole family including siblings of the child with ASD, the sibling population is rarely included in research related to children with ASD, and there is only limited services available for them. This exploratory study (n=6) is aimed at better understanding the siblings' lives in their family settings in order to identify the siblings' unmet needs and determine how they have been influenced by the child with ASD. This study is also aimed at identifying the most appropriate support for the siblings to help them cope better. The study followed the Resiliency Model of Family Stress, Adjustment, and Adaptation and a narrative theory approach. An in-depth interview with the parents was conducted for the study, so the findings reflect the parents' perception of the siblings. All the themes emerged into two categories: life in the family setting and supports. The findings indicate that the families are striving for balance between the siblings and the children with ASD, but still tend to focus more on the children with ASD. Also, the families tend to have autonomous personal support systems. The parents tend to perceive that these personal support systems are good enough for the siblings; therefore, the parents do not feel that formal support for the siblings was necessary. As a result of the findings, recommendations are made for the organizations that work with individuals with ASD to provide more appropriate services for the families of children with ASD, including siblings. Also, recommendations are made for future studies to clarify more factors related to the siblings due to the limitation of this study; the siblings' lives were reflected vicariously via the parents.
ContributorsJeong, Seong Hae (Author) / Marsiglia, Flavio F (Thesis advisor) / Ayers, Stephanie (Committee member) / Adams, James (Committee member) / Arizona State University (Publisher)
Created2013
Description
Electromigration in metal interconnects is the most pernicious failure mechanism in semiconductor integrated circuits (ICs). Early electromigration investigations were primarily focused on aluminum interconnects for silicon-based ICs. An alternative metallization compatible with gallium arsenide (GaAs) was required in the development of high-powered radio frequency (RF) compound semiconductor devices operating at higher current densities and elevated temperatures. Gold-based metallization was implemented on GaAs devices because it uniquely forms a very low resistance ohmic contact and gold interconnects have superior electrical and thermal conductivity properties. Gold (Au) was also believed to have improved resistance to electromigration due to its higher melting temperature, yet electromigration reliability data on passivated Au interconnects is scarce and inadequate in the literature. Therefore, the objective of this research was to characterize the electromigration lifetimes of passivated Au interconnects under precisely controlled stress conditions with statistically relevant quantities to obtain accurate model parameters essential for extrapolation to normal operational conditions. This research objective was accomplished through measurement of electromigration lifetimes of large quantities of passivated electroplated Au interconnects utilizing high-resolution in-situ resistance monitoring equipment. Application of moderate accelerated stress conditions with a current density limited to 2 MA/cm2 and oven temperatures in the range of 300°C to 375°C avoided electrical overstress and severe Joule-heated temperature gradients. Temperature coefficients of resistance (TCRs) were measured to determine accurate Joule-heated Au interconnect film temperatures. A failure criterion of 50% resistance degradation was selected to prevent thermal runaway and catastrophic metal ruptures that are problematic of open circuit failure tests. Test structure design was optimized to reduce resistance variation and facilitate failure analysis. Characterization of the Au microstructure yielded a median grain size of 0.91 ìm. All Au lifetime distributions followed log-normal distributions and Black's model was found to be applicable. An activation energy of 0.80 ± 0.05 eV was measured from constant current electromigration tests at multiple temperatures. A current density exponent of 1.91 was extracted from multiple current densities at a constant temperature. Electromigration-induced void morphology along with these model parameters indicated grain boundary diffusion is dominant and the void nucleation mechanism controlled the failure time.
ContributorsKilgore, Stephen (Author) / Adams, James (Thesis advisor) / Schroder, Dieter (Thesis advisor) / Krause, Stephen (Committee member) / Gaw, Craig (Committee member) / Arizona State University (Publisher)
Created2013
Description
Western landscape photography helped to create an imaginative perception of a new nation for Americans. Early nineteenth-century photographers captured a vision of uncharted terrain that metaphorically fulfilled a two-fold illusion: an untouched Eden and a land ready and waiting for white settlement. The sublime and picturesque experiences of the West provided artists a concept that could be capitalized upon by employing various forms of manipulation. In the twentieth-century, the role of landscape photography evolved as did the advancement of the West. Images of wilderness became art and photographers chose to view the western landscape differently. Some focused more sharply and critically on the relationship between the land and the people who lived on it. The influential exhibition in 1975, New Topographics: Photographs of a Man-altered Landscape presented work that showed a landscape altered, marked by power lines, houses, and fences. The West as Eden no longer existed. Today, photographers continue to examine, image, and experience western land anew. In this thesis I examine the relationship of contemporary landscape photography and the role of the West, guided by an analysis that traces the history of American ideologies and attitudes toward natural land. The artists I have chosen recognize landscape not as scenery but as the spaces and systems people inhabit, and use manipulative strategies that emphasize an artificial character of the West. Their work elicits antecedent mythologies, pictorial models, and American ideologies that continue to perpetuate internationally.
ContributorsHerden, Nicole (Author) / Fahlman, Betsy (Thesis advisor) / Serwint, Nancy (Committee member) / Klett, Mark (Committee member) / Arizona State University (Publisher)
Created2013
Description
Organic optoelectronic devices have remained a research topic of great interest over the past two decades, particularly in the development of efficient organic photovoltaics (OPV) and organic light emitting diodes (OLED). In order to improve the efficiency, stability, and materials variety for organic optoelectronic devices a number of emitting materials, absorbing materials, and charge transport materials were developed and employed in a device setting. Optical, electrical, and photophysical studies of the organic materials and their corresponding devices were thoroughly carried out. Two major approaches were taken to enhance the efficiency of small molecule based OPVs: developing material with higher open circuit voltages or improved device structures which increased short circuit current. To explore the factors affecting the open circuit voltage (VOC) in OPVs, molecular structures were modified to bring VOC closer to the effective bandgap, ∆EDA, which allowed the achievement of 1V VOC for a heterojunction of a select Ir complex with estimated exciton energy of only 1.55eV. Furthermore, the development of anode interfacial layer for exciton blocking and molecular templating provide a general approach for enhancing the short circuit current. Ultimately, a 5.8% PCE was achieved in a single heterojunction of C60 and a ZnPc material prepared in a simple, one step, solvent free, synthesis. OLEDs employing newly developed deep blue emitters based on cyclometalated complexes were demonstrated. Ultimately, a peak EQE of 24.8% and nearly perfect blue emission of (0.148,0.079) was achieved from PtON7dtb, which approaches the maximum attainable performance from a blue OLED. Furthermore, utilizing the excimer formation properties of square-planar Pt complexes, highly efficient and stable white devices employing a single emissive material were demonstrated. A peak EQE of over 20% for pure white color (0.33,0.33) and 80 CRI was achieved with the tridentate Pt complex, Pt-16. Furthermore, the development of a series of tetradentate Pt complexes yielded highly efficient and stable single doped white devices due to their halogen free tetradentate design. In addition to these benchmark achievements, the systematic molecular modification of both emissive and absorbing materials provides valuable structure-property relationship information that should help guide further developments in the field.
ContributorsFleetham, Tyler Blain (Author) / Li, Jian (Thesis advisor) / Alford, Terry (Committee member) / Adams, James (Committee member) / Arizona State University (Publisher)
Created2014
Description
The history of jade in many ways reflects the evolution of Chinese civilization, encompassing its entire history and geographical extent and the many cultural traditions associated with the various regions that have finally been brought together in the unity of present-day China. The archaic jade collections investigated in this thesis, from an archaeological point of view, primarily consist of pieces from the late Neolithic through early historic era, named the "Jade Age" by academics. Although well-researched museum catalogues of archaic Chinese jades have been widely published by major museums in the United States, they are mostly single collection oriented. It is, then, necessary to conduct research examining the overall picture of collecting practices in the U.S. Given the proliferation of fake early jades, this study will provide an essential academic reference for researchers, students, and the present art market. This thesis seeks to explore how shifting tastes, political climates, and personal ambitions, as well as various opportunities and personalities, were instrumental factors in shaping these important collections of archaic Chinese jades in the U.S. today.
ContributorsWang, Yijing (Author) / Brown, Claudia (Thesis advisor) / Fahlman, Betsy (Committee member) / Baker, Janet (Committee member) / Schleif, Corine (Committee member) / Arizona State University (Publisher)
Created2014
Description
Organic light emitting diodes (OLEDs) are a promising approach for display and solid state lighting applications. However, further work is needed in establishing the availability of efficient and stable materials for OLEDs with high external quantum efficiency's (EQE) and high operational lifetimes. Recently, significant improvements in the internal quantum efficiency or ratio of generated photons to injected electrons have been achieved with the advent of phosphorescent complexes with the ability to harvest both singlet and triplet excitons. Since then, a variety of phosphorescent complexes containing heavy metal centers including Os, Ni, Ir, Pd, and Pt have been developed. Thus far, the majority of the work in the field has focused on iridium based complexes. Platinum based complexes, however, have received considerably less attention despite demonstrating efficiency's equal to or better than their iridium analogs. In this study, a series of OLEDs implementing newly developed platinum based complexes were demonstrated with efficiency's or operational lifetimes equal to or better than their iridium analogs for select cases.
In addition to demonstrating excellent device performance in OLEDs, platinum based complexes exhibit unique photophysical properties including the ability to form excimer emission capable of generating broad white light emission from a single emitter and the ability to form narrow band emission from a rigid, tetradentate molecular structure for select cases. These unique photophysical properties were exploited and their optical and electrical properties in a device setting were elucidated.
Utilizing the unique properties of a tridentate Pt complex, Pt-16, a highly efficient white device employing a single emissive layer exhibited a peak EQE of over 20% and high color quality with a CRI of 80 and color coordinates CIE(x=0.33, y=0.33). Furthermore, by employing a rigid, tetradentate platinum complex, PtN1N, with a narrow band emission into a microcavity organic light emitting diode (MOLED), significant enhancement in the external quantum efficiency was achieved. The optimized MOLED structure achieved a light out-coupling enhancement of 1.35 compared to the non-cavity structure with a peak EQE of 34.2%. In addition to demonstrating a high light out-coupling enhancement, the microcavity effect of a narrow band emitter in a MOLED was elucidated.
In addition to demonstrating excellent device performance in OLEDs, platinum based complexes exhibit unique photophysical properties including the ability to form excimer emission capable of generating broad white light emission from a single emitter and the ability to form narrow band emission from a rigid, tetradentate molecular structure for select cases. These unique photophysical properties were exploited and their optical and electrical properties in a device setting were elucidated.
Utilizing the unique properties of a tridentate Pt complex, Pt-16, a highly efficient white device employing a single emissive layer exhibited a peak EQE of over 20% and high color quality with a CRI of 80 and color coordinates CIE(x=0.33, y=0.33). Furthermore, by employing a rigid, tetradentate platinum complex, PtN1N, with a narrow band emission into a microcavity organic light emitting diode (MOLED), significant enhancement in the external quantum efficiency was achieved. The optimized MOLED structure achieved a light out-coupling enhancement of 1.35 compared to the non-cavity structure with a peak EQE of 34.2%. In addition to demonstrating a high light out-coupling enhancement, the microcavity effect of a narrow band emitter in a MOLED was elucidated.
ContributorsEcton, Jeremy David (Author) / Li, Jian (Thesis advisor) / Adams, James (Committee member) / Alford, Terry (Committee member) / Arizona State University (Publisher)
Created2014
Description
Organic light emitting diodes (OLEDs) is a rapidly emerging technology based on organic thin film semiconductors. Recently, there has been substantial investment in their use in displays. In less than a decade, OLEDs have grown from a promising academic curiosity into a multi-billion dollar global industry. At the heart of an OLED are emissive molecules that generate light in response to electrical stimulation. Ideal emitters are efficient, compatible with existing materials, long lived, and produce light predominantly at useful wavelengths. Developing an understanding of the photophysical processes that dictate the luminescent properties of emissive materials is vital to their continued development. Chapter 1 and Chapter 2 provide an introduction to the topics presented and the laboratory methods used to explore them. Chapter 3 discusses a series of tridentate platinum complexes. A synthetic method utilizing microwave irradiation was explored, as well as a study of the effects ligand structure had on the excited state properties. Results and techniques developed in this endeavor were used as a foundation for the work undertaken in later chapters. Chapter 4 introduces a series of tetradentate platinum complexes that share a phenoxy-pyridyl (popy) motif. The new molecular design improved efficiency through increased rigidity and modification of the excited state properties. This class of platinum complexes were markedly more efficient than those presented in Chapter 3, and devices employing a green emitting complex of the series achieved nearly 100% electron-to-photon conversion efficiency in an OLED device. Chapter 5 adapts the ligand structure developed in Chapter 4 to palladium. The resulting complexes exceed reported efficiencies of palladium complexes by an order of magnitude. This chapter also provides the first report of a palladium complex as an emitter in an OLED device. Chapter 6 discusses the continuation of development efforts to include carbazolyl components in the ligand. These complexes possess interesting luminescent properties including ultra-narrow emission and metal assisted delayed fluorescence (MADF) emission.
ContributorsTurner, Eric (Author) / Li, Jian (Thesis advisor) / Adams, James (Committee member) / Alford, Terry (Committee member) / Arizona State University (Publisher)
Created2014
Description
In this thesis, I investigate the anatomical excesses represented in the works of Jean-Auguste-Dominique Ingres. In recent years, art historical scholarship on Ingres has multiplied after being quiescent for much of the twentieth century, as contemporary scholars perceive the unusual contradictions in his works. I introduce the concepts of pathological versus imaginary distortions. Pathological distortions are distortions that represent diseased bodies, such as the goiters in many of Ingres's female figures, whereas imaginary distortions are not anatomically possible, such as the five extra vertebrae in the Grande Odalisque. Ingres employed both of these types of these distortions in his bodies, and I discuss how these two types of distortions can be read differently.
My thesis is that Ingres employed extended anatomical variations-in his paintings, most notably in his female figures, for several reasons: to reconcile his anxiety about originality while remaining within the tradition of Classicism and "disegno," to pay homage to his predecessors who were also the masters of line, and to highlight his command of line and drawing. Though Ingres has never been a strictly Neoclassical artist in the Davidian tradition, the Romantic elements of his work are underlined further by these anatomical variations.
My thesis is that Ingres employed extended anatomical variations-in his paintings, most notably in his female figures, for several reasons: to reconcile his anxiety about originality while remaining within the tradition of Classicism and "disegno," to pay homage to his predecessors who were also the masters of line, and to highlight his command of line and drawing. Though Ingres has never been a strictly Neoclassical artist in the Davidian tradition, the Romantic elements of his work are underlined further by these anatomical variations.
ContributorsEpstein, Danya (Author) / Codell, Julie F. (Thesis advisor) / Gully, Anthony (Committee member) / Fahlman, Betsy (Committee member) / Arizona State University (Publisher)
Created2015
Description
The turmoil that China endured during the twentieth century triggered a series of social and political revolutions. As China struggled to resolve domestic questions of dynasticism or democracy and nationalism or communism, Western industrialization and imperialism dragged China rapidly into the globalizing world. Likewise, Chinese painting had to confront the West, as Chinese artists dealt with the twentieth-century version of the recurring question of modernizing Chinese painting for its times: how does one reconcile an ancient painting tradition with all the possibilities Western interactions introduced? This dissertation focuses on one artist's lifelong struggle, often overlooked, to answer this question. By examining C. C. Wang (1907-2003) and his life in art, this case study reveals broader truths about how twentieth century Chinese diaspora painters, such as Wang, modernized the tradition of Chinese ink painting.
Wang's reputation as a connoisseur of ancient Chinese painting has overshadowed his own artwork, creating a dearth of research on his artistic development. Using public and private sources, this dissertation applied stylistic analysis to track this development. The analysis reveals an artist's lifelong endeavor to establish a style that would lift the Chinese painting tradition into a modern era, an endeavor inspired by modern Western art ideas and a desire to play a role in the larger movement of elevating Chinese painting. The argument is made that these efforts establish Wang as an influential twentieth century Chinese ink painter.
To clarify Wang's role within the broader movement of Chinese diaspora painters, this dissertation employs a comparison study of Wang with such established twentieth century ink painting artists as Zhang Daqian, Liu Guosong, and Yu Chengyao. It is
asserted that the 1949 diaspora forced this cohort of artists to adjust their style and to transcend traditional Chinese painting by integrating newly-salient ideas from Western art, particularly the abstract movement. Meanwhile, the essential Chinese identity in their art collectively became more significant. The solidarity of purpose and identity is a distinctive part of the answer this group of twentieth century Chinese diaspora painters proposed to their generation's inherited challenge of enriching the tradition.
Wang's reputation as a connoisseur of ancient Chinese painting has overshadowed his own artwork, creating a dearth of research on his artistic development. Using public and private sources, this dissertation applied stylistic analysis to track this development. The analysis reveals an artist's lifelong endeavor to establish a style that would lift the Chinese painting tradition into a modern era, an endeavor inspired by modern Western art ideas and a desire to play a role in the larger movement of elevating Chinese painting. The argument is made that these efforts establish Wang as an influential twentieth century Chinese ink painter.
To clarify Wang's role within the broader movement of Chinese diaspora painters, this dissertation employs a comparison study of Wang with such established twentieth century ink painting artists as Zhang Daqian, Liu Guosong, and Yu Chengyao. It is
asserted that the 1949 diaspora forced this cohort of artists to adjust their style and to transcend traditional Chinese painting by integrating newly-salient ideas from Western art, particularly the abstract movement. Meanwhile, the essential Chinese identity in their art collectively became more significant. The solidarity of purpose and identity is a distinctive part of the answer this group of twentieth century Chinese diaspora painters proposed to their generation's inherited challenge of enriching the tradition.
ContributorsHua, Ming (Author) / Brown, Claudia (Thesis advisor) / Baker, Janet (Committee member) / Fahlman, Betsy (Committee member) / Arizona State University (Publisher)
Created2014
Description
This thesis focuses on the theoretical work done to determine thermodynamic properties of a chalcopyrite thin-film material for use as a photovoltaic material in a tandem device. The material of main focus here is ZnGeAs2, which was chosen for the relative abundance of constituents, favorable photovoltaic properties, and good lattice matching with ZnSnP2, the other component in this tandem device. This work is divided into two main chapters, which will cover: calculations and method to determine the formation energy and abundance of native point defects, and a model to calculate the vapor pressure over a ternary material from first-principles. The purpose of this work is to guide experimental work being done in tandem to synthesize ZnGeAs2 in thin-film form with high enough quality such that it can be used as a photovoltaic. Since properties of photovoltaic depend greatly on defect concentrations and film quality, a theoretical understanding of how laboratory conditions affect these properties is very valuable. The work done here is from first-principles and utilizes density functional theory using the local density approximation. Results from the native point defect study show that the zinc vacancy (VZn) and the germanium antisite (GeZn) are the more prominent defects; which most likely produce non-stoichiometric films. The vapor pressure model for a ternary system is validated using known vapor pressure for monatomic and binary test systems. With a valid ternary system vapor pressure model, results show there is a kinetic barrier to decomposition for ZnGeAs2.
ContributorsTucker, Jon R (Author) / Van Schilfgaarde, Mark (Thesis advisor) / Newman, Nathan (Committee member) / Adams, James (Committee member) / Arizona State University (Publisher)
Created2011