VictorJuiz/thesis huggingface dataset:
Resistive switching random access memory - device scaling in 3D architecture and integration with complementary metal oxide semiconductor
Keywords: Electrical Engineering.

The rapid development and proliferation of mobile devices, such as smartphones, has enabled quick and easy Internet access, providing various sensor data from those devices. Amid a plethora of data, there has been an increase in demand for higher density storage class memory (SCM), which has been met through feature size scaling. However, it is expected that mainstream memory technology - NAND Flash - going beyond the 1z nm technology node will face its ultimate scaling limit. Resistive random access memories (RRAM) based on metal oxide is widely considered one of the most prominent next-generation non-volatile memory (NVM) technologies. Its key attributes, including better endurance, retention, speed, low programming voltages, and 3D integration capacity, make it a promising candidate for future SCM. In the first part of this dissertation, I demonstrate ultimate vertical scaling for RRAM in the 3D architecture (3D-RRAM) by employing the atomically thin nature of graphene edge (~3 Å thick). In this architecture, RRAM cell is formulated at the intersection between the pillar electrode and graphene edge electrode. Our 3D-RRAM with graphene edge electrode shows drastic vertical scaling of an individual stack height, allowing our device to stack up to 200 layers, whereas NAND Flash products can only go several tens of layers. Graphene has an outstanding electrical property due to its superior sheet resistance per thickness, and our study by SPICE simulation suggests that our 3D-RRAM can achieve > 100 Gb array size. Our fabricated 2-layer of 3D-RRAM exhibits excellent electrical characteristics, such as high resistance values and good endurance. Moreover, the role of top electrode (TE) and bottom electrode (BE) is exchangeable with each other in our device depending on the initial device programming voltage polarity (the forming process), making it possible to monitor the movement of oxygen ions using Raman image analysis. Due to the low switching voltage in the reverse switching mode, we are able to achieve very low switching power consumption as compared to recently reported RRAMs. This work contributes to research and development of energy efficient, high density non-volatile memory, which is needed to meet the growing demands of storing and processing of data in future computing systems. The last chapter of this dissertation introduces the integration of RRAM on a CMOS logic platform. In this study, we show it is possible to build fully functional RRAMs starting from Si CMOS wafers from a commercial foundry and successfully integrate RRAM as a back end of line (BEOL) on the Si CMOS wafer. In this chapter, I present the architecture of a compact, one-transistor-two-RRAM (1T2R) array, with associated read/write scheme. This chapter describes the process flow of RRAM integration and reports on the evaluation of RRAMs in an array with a memory array test scheme. The development of CMOS-compatible RRAM is also covered in the final chapter.
Resource, development and tradition : explaining persistence and costs of intergenerational marital norms in South Korea
Keywords: Sociology.

This dissertation is comprised of an introduction and three independent papers that explore the themes of change and continuity in patrilineal marriage norms centered on patrilineal descent, patrilocal residence, and generational patriarchy in contemporary South Korea. Western European family with bilateral kinship and nuclear authority structure is taken as the default norm in the sociology of family literature, but extended family systems that embody a sex-generation hierarchy are much more common across the globe. Most extended family systems are based on patrilineality (recognition of descent only through the male links), which in turn is associated with patrilocality (residence with or near husband's kin) and generational patriarchy. Whether and to what extent the patrilineal family system has disintegrated or stayed resilient in the contemporary era is a critical issue to study, as it has important implications for gender inequality in most non-Western contexts. The three papers in this dissertation each address whether and how the traditionally patrilineal family system based on East Asian Confucianism has changed through the recent modernization processes in the context of South Korea. Collectively the findings demonstrate that although some features of the patrilineal family such as patrilocality have shifted towards bilateralism as a result of urbanization and the growing importance of economic resources, other structural aspects such as generational patriarchy and state support of the patrilineal family structure are not necessarily tied to economic development, and thus continue to be reproduced even after Korea has reached the economic status of a developed country. The findings have theoretical implications for studying family structure, economic development and gender inequality in other contexts with a patrilineal family system beyond Korea and East Asia.
Return to sender : photography, art, and the mail, 1845-1945
Keywords: Art and Art History.

This dissertation examines the historical relationship between photography and the postal service in the United States, tracing the aesthetic influence of the mail on photographic practice as both forms developed across the nineteenth and twentieth centuries. Since the early decades of photography, practitioners have relied on a burgeoning international postal system in order to send photographs, materials, and information about technological developments across long distances. The official announcement of the daguerreotype photographic process in 1839 occurred just six years before the landmark Postal Act of 1845, in which the United States Congress reduced postage rates to allow the mail to be, for the first time, a viable form of communication for the majority of Americans. Central to the history of photography though rarely discussed within it, this dissertation examines how the mail proved a key agent in the evolution of the photograph from a singular and costly object to a reproducible and disseminable image. Through the work of photographers Southworth & Hawes, William Henry Jackson, Anne Brigman, Alfred Stieglitz, John Gutmann, and Francesca Woodman, "Return to Sender" considers how American photographers have conceptualized transmission and communication as aspects, and even primary goals, of their work. In so doing, this dissertation seeks to reconsider traditional histories of photography predicated on the priorities of modernist formalism, instead framing the history of the photographic medium as one of transmission and exchange.
Revoking work permits of spouses of tech immigrant workers will reduce Silicon Valley’s competitive advantage
Keywords:  Department of Communication
visa
immigration
reform
Trump
H-4
Department of Communication and Journalism
Thesis

Last year, President Trump signed the “Buy American and Hire American” executive order that
argued for the need to protect the interests of United States workers. One of the decisions driven by
this executive order will be the implementation of a rule that will eliminate work authorization of
spouses of H-1B — or high-skilled visa holders. The decision threatens to upend the tech industry
at a time when Silicon Valley’s big companies — which rely on H-1B visa workers — are already
facing a labor shortage. If their spouses aren’t allowed to work, other countries with less-restrictive
visa policies will attract these skilled workers, opponents of the rule change say.
Revolution or Renaissance: The Effect of Chinese Leadership Transition on Foreign Policy
Keywords:  Stanford Global Studies
Stanford Global Studies
East Asian Studies
China
Leadership Transition
Foreign Outlook
Thesis

This thesis explores the impact of Chinese leadership transition on the contours of Chinese foreign policy. Much of the current literature on this topic has often dealt with Chinese leaders and their impact on foreign policy in silo, oftentimes forgetting that many of the foreign policy initiatives put forth by subsequent leaders have already been presented in the previous administration. This thesis explores the tenure of China’s three latest top leaders--Jiang Zemin, Hu Jintao and Xi Jinping--and compares the leadership of Xi against his two predecessors to assess how the process of leadership transition has had an impact on China’s foreign policy. By extension, this thesis also discusses and highlights the assumptions that we hold when discussing the Chinese political system and their implications for our understanding of the larger context of political leadership in China.
Ring-opening metathesis polymerization of substituted cyclopropenes
Keywords: Chemistry.

Life would not be possible without precise macromolecular sequence control. The ability of biological systems to encode information, transmit instructions, and catalyze chemical reactions relies on the proper ordering of monomeric units. While our synthetic capabilities may trail those nature has developed through billions of years of evolution, continued advances in polymer science have allowed ever greater control over polymer microstructures. Specifically, living polymerization techniques, such as ring-opening metathesis polymerization (ROMP), have given us the tools to synthesize polymers with defined molecular weights and narrow molecular weight distributions. While ROMP is typically driven by the release of ring strain, surprisingly little research has been performed on the polymerization of cyclopropenes (CPEs), the monocyclic olefin with the highest ring strain. We believed that the high strain energy of this class of monomers along with the ability to tune the steric environment through strategic substitutions would result in unique reactivity and potential to control monomer sequences. In building a library of CPEs capable of ROMP, we discovered a unique class of CPEs that only singly added to Grubbs third generation catalyst followed by no further homopolymerization. We have used this behavior to develop a system for perfectly alternating ROMP with CPEs and low-strain cyclic olefins. Further investigations have shown that this technique can be extended to incorporate other low-strain cycles, allowing for functionalities to be directly incorporated into the polymer backbone. Additionally, with these molecules in hand, we have been able to incorporate single functional units into a polymer backbone by addition of precisely one equivalent of monomer relative to catalyst. At first using this technique to synthesize telechelic polymers, we have successfully optimized this system to allow the incorporation of exactly one monomer into a ROMP polymer at any defined location along the backbone, giving unprecedented control over polymer sequence using via solution chemistry.
Risky hearts : Nigerian marketcraft in the global south
Keywords: Anthropology.

Since the 1990s, bustling markets across Asia and the Middle East have seen an uptick of thousands of African merchant travelers. This dissertation traces how these trans-continental manufacturing and commercial landscapes have been transformed by a key set of actors - a young mercantile generation from the massive petrostate of Nigeria. Drawn from 18 months of ethnographic fieldwork based primarily in the Nigerian megacity of Lagos, as well as eastern Nigeria and the contemporary African trade sites of Dubai (United Arab Emirates), Istanbul (Turkey), and Guangzhou (China), the dissertation analyzes how such south-south mobilities have transformed the politics of commercial space and nationalist imaginaries. First, the dissertation argues that such far-flung commercial mobilities are underpinned by highly decentralized and monopoly-resistant transnational market formations in Nigeria that are defensive against corporate and non-black foreign actors. I employ the concept of marketcraft to highlight the centrality of processes of security and protection in market formation, which are shaped by the affective orientations, ethics, and historical contingencies of the actors and politics that create them. Second, the dissertation examines how Nigerian merchants engage with ethno-regional politics and neo-secessionism upon return and how transnational south-south diasporic formations have transformed Nigerian social imaginaries and discourses of postcolonial political and economic sovereignty.
RNA structural regulation of reverse transcription initiation in HIV [electronic resource]
Keywords: Biophysics.

The process of reverse transcription in HIV is a crucial early step in the viral replication cycle and must take place before infection is complete. During this process, the viral single-stranded RNA genome is reverse transcribed into double-stranded DNA for incorporation into the host cell genome. HIV drug treatments that inhibit reverse transcription have been highly successful in treating and preventing infection. Understanding how this process is regulated on a molecular level is crucial for understanding how reverse transcription defects prevent viral replication. This work presents a series of biochemical and biophysical studies on the macromolecular components involved in regulating reverse transcription initiation in HIV.
Robotic mobility on small solar system bodies : design, control, and autonomy
Keywords: Mechanical Engineering.

In this thesis, we investigate the mobility challenges associated with robotic exploration of small solar system bodies, such as comets and asteroids. We open with a discussion on the surface environment of small bodies, and in particular, how their extremely weak gravity motivates hopping as a promising form of locomotion for long-distance traverses. We then propose an adaptable rover architecture called ``Hedgehog''---a minimalistic, internally-actuated, hopping rover designed for targeted mobility in such low-gravity environments. By applying internal torques to three mutually-orthogonal flywheels, the rover's chassis rotates, giving rise to ground reaction forces and various motion primitives, including long-range hopping, short precise tumbling, and small pose adjustments. We propose various models for analyzing the dynamics of these motion primitives and derive control laws for achieving desired motions. We then discuss various methods for conducting experiments in a reduced-gravity environment, including a custom six-degree-of-freedom laboratory test bed and parabolic flights. We validate our control laws in these test beds and demonstrate unprecedented motion accuracy for internally-actuated hoppers. Finally, we broaden our focus to general hopping platforms and consider various algorithmic tools for autonomous exploration. Specifically, we develop a suite of tools for motion planning, localization, and traversability analysis, with a careful attention on the various sources of model uncertainty and the complex dynamics of hopping trajectories. Despite the stochastic nature of bouncing dynamics, we demonstrate through high-fidelity simulations that a hopping rover can efficiently traverse highly irregular bodies that would otherwise be inaccessible to traditional rovers.
Role of CD47 in Clonal Expansion of Vascular Smooth Muscle Cells in Atherosclerosis
Keywords:  Department of Biology
Department of Biology
Stanford University
cardiovascular medicine
molecular biology
atherosclerosis
plaque
smooth muscle cells
clonal expansion
Thesis

Background
Cardiovascular disease claims more lives each year than all forms of cancer combined, and atherosclerosis, a form of cardiovascular disease, is the process of fatty deposit build-up in arterial cells to form atherosclerotic lesions. Recent studies show that vascular smooth muscle cells (SMCs) act as a cardiovascular risk factor independent of cholesterol levels, yet not much is known because SMCs tend to lose their lineage-specific markers during plaque progression, which results in the underestimation of SMC contribution to plaque expansion using traditional histology methods. For the same reason, little is known about SMC biology in atherosclerosis and in developing therapeutics to treat diseased SMCs in the plaques.
Methods and Results
To overcome this problem, a unique SMC lineage-tracing murine model carrying a "Rainbow" reporter was developed. When exposed to tamoxifen, this mouse underwent gene recombination and randomly expressed one of three colors - yellow, blue or red - exclusively in SMCs such that each cell and its descendants expressed the same color. Mice containing the "Rainbow" reporter were crossed with Apolipoprotein E knockout (ApoE-/-) mice, a murine model of atherosclerosis, to generate "Rainbow mice" for studying SMCs during atherosclerosis. Use of this model showed that SMCs underwent clonal expansion in the plaque. Flow cytometry analysis subsequently showed that diseased SMCs in the plaque from Rainbow mice expressed higher levels of the "don't eat me" molecule CD47 compared to that of healthy SMCs. SMCs from the plaque were also sorted to feed the phagocytes, and CD47high SMCs were found to be more resistant to efferocytosis. Then, Rainbow mice were fed with 18 weeks of high fat diet to induce atherosclerosis and were treated with control IgG or anti-CD47 antibody. The anti-CD47 antibody treated mice showed significantly reduced plaque size and SMC clonal expansion.
Conclusion
CD47 overexpression facilitated SMCs clonal expansion by allowing them to escape from efferocytosis. Ultimately, the use of an anti-CD47 strategy was potentially beneficial to help remove diseased SMCs from the plaque to decrease the size of the established plaque and lower the risk of heart attack and stroke.
The role of contacts and interfaces on the performance of perovskite solar cells
Keywords: Materials Science and Engineering.

With business as usual, our planet is expected to warm by over 4°C in the next 80 years. Those four degrees mean more chaotic weather, increased food scarcity, unprecedented flooding, and the many other impacts of global warming. To curtail these impacts requires a rapid expansion of carbon-free and renewable energy, and one promising source of that energy is perovskite solar cells -- a novel photovoltaic technology that despite its nascence has already surpassed power-conversion efficiencies of 22%. The halide perovskites of focus for solar applications are unique in their tolerance of many ionic defects. This property results in mixed electronic-ionic conduction, that requires new design rules and new models of understanding for perovskites used in solar cells. This work presents advances in understanding interfaces and optimizing contacts with the aim of closing the gap between the thin film properties of perovskites and their solar cell device efficiencies. First, I demonstrate how the presence of mobile ionic defects in perovskite solar cells changes the nature of perovskite-electrode interfaces, and therefore the impact of carrier-selective contacts on device performance. Translating this understanding of the impact of contact materials into contact design, I next present my results combining thermally evaporated organic molecules and atomic layer deposited vanadium oxide, to develop a contact with increased optical transparency and thermal stability for perovskite-silicon tandem solar cells. Finally, expanding on the impacts of ionic defects, I present a new understanding of photo-induced trap formation -- an energy loss-pathway that currently limits the power-conversion efficiency of many perovskite solar cells -- highlighting interfacial treatments as a pathway towards trap passivation and improved efficiency. Together, this work highlights the dynamic and impactful nature of perovskite interfaces, and how, by optimizing them, we can continue to advance the already remarkable efficiency of perovskite solar cells.
Role of Frizzled Conformational Changes and Membrane Composition in the Frizzled-Dishevelled Interaction
Keywords:  Department of Biology
Wnt signaling
Frizzled
Dishevelled
Structural Biology
Biochemistry
Thesis

The Wnt signaling pathway plays an essential role in embryonic development and the regulation of many physiological processes. Defects in Wnt signaling can contribute to a variety of diseases including cancer, diabetes, and familial exudative vitreoretinopathy, among others. In β-catenin-dependent “canonical” Wnt signaling, Wnt binds to a complex of the transmembrane receptors Frizzled (Fzd) and LRP5/6, which induces recruitment of the cytoplasmic scaffold protein Dishevelled (Dvl). Very little is known about the mechanism and function of Dvl recruitment to Fzd. It is unclear whether the PDZ or DEP domains of Dvl bind Fzd, and how local membrane environment may affect Fzd-Dvl binding. A major limitation of the previous work on Fzd-Dvl interaction is the use of Fzd peptides instead of purified protein. Here, we use purified Dvl2 and Fzd4 protein to better understand how the Fzd-Dvl interaction drives Wnt signaling. We show that both purified Dvl2 DEP and PDZ bind to purified Fzd4 in fluorescence polarization studies. To our knowledge, this is the first demonstration of Fzd-Dvl binding using purified full-length Fzd protein. We also aim to determine the effects of Fzd conformational changes on Dvl recruitment. We design Fzd mutants using known familial exudative vitreoretinopathy (FEVR) mutants and a homology model of Fzd4 based on the crystal structure of full-length Smoothened. Using a cell-based signaling assay, we provide evidence that Fzd undergoes a conformational shift during Wnt activation and that this activating conformation is necessary for β-catenin signaling. The abrogation of Wnt signaling seen in Fzd with cytoplasm-facing mutations provides additional support for the existence of a cytoplasmic docking site on Frizzled. Lastly, we investigate the effect of the local lipid environment on Fzd-Dvl binding. We show that purified Dvl2 PDZ does not interact with lipid nanodiscs, and that purified Dvl2 DEP and PDZ do not interact with liposomes. Our work is an important first step in elucidating the mechanism of Fzd-Dvl recruitment and activation of downstream signaling effectors.