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Smart windows with tunable optical transmittance to electrical-, thermal-, mechanical stimuli offer promising solutions for energy saving application in the field of novel building, vehicles, agriculture, etc. Among which, the thermal responsive smart window arouses great interest due to its passive response, without introducing external energy. Numerous studies have been conducted, yet several critical challenges remain unresolved, including undesired transition temperature, slow transition in temperature span, low transparency at clear state, and limited optical modulation capability.The phase changing polymer shows extraordinary thermal responsive optical switching capability base on melting and crystallization. By introducing another distinguishable phase into the established phase changing polymer network to create refractive index matching and mismatching, the optical modulation is achieved at different temperature stage.I developed a series of thermal responsive smart window materials based on side chain crystallizable phase changing polymer, to accomplish smart windows with tunable transition temperature ranging from 32 °C to 45 °C, ultra-high low-temperature visible transmittance above 91%, and excellent optical modulation capability higher than 80%.Chapter 1 outlined the background of the imperative for smart window of modulating solar radiation, for energy conservation purposes.In Chapter 2, I introduced a thermal responsive phase changing polymer (TPCC), which was synthesized from hydrophilic and hydrophobic monomer blends. The phase transition of the semicrystalline polymer led to a refractive index drop, effectuating light scattering and facilitating optical modulation across the solar spectrum. The transition temperature for this smart window was designed to be 32 °C.In Chapter 3, I presented a semicrystalline polymer with exceptional transparency between 20 °C to 60 °C. By employing such polymer as the functional thermal responsive material, a high transmitted state of the smart window was achieved, with transmittance varying from 91.4% at 20 °C to 2.7% at 50 °C. The transition temperature for this smart window design was around 42 °C.In Chapter 4, based on the previous transparent semicrystalline polymer, I enhanced the smart window performance by introducing glass beads to realize a controllable light scattering. A high contrast in optical transmittance between 96.8% and 3.2% was achieved, signifying its capability of optical tuning.These materials demonstrated the viability of using such semicrystalline polymers for smart window applications to address a high capability of optical modulation >80% with a more desirable transition temperature between 32 °C and 45 °C. A total low-temperature transparency and wavelength selected modulation could be further achieved by material selection and refractive index tuning cooperate with the established materials.

This dissertation aims to address the lack of transcultural and historical perspective in the study of the Chinese term shishi and its role in the contemporary literature among the current scholarship. To begin with, the study traces the origin and genealogical development of shishi as a literary concept. It concludes that although it was initially invented as a translation for the Western term “epic,” the connotation of shishi was then greatly expanded and modified by Chinese intellectuals and should be understood as a unique aesthetic paradigm for evaluating literary works and inspiring writers, especially in terms of the criticism and the creation of historical fiction. Guided by the craving for building a unified identity for the newborn nation with literary works inspired by communist ideology, the revolutionary historical novel from the “Seventeen-Year Era” (1949-1966) becomes the embodiment of the classic ideas of shishi: heroism and optimistic belief in social progress. With the revolutionary era coming to an end, the orthodox historical narrative was challenged by writers and critics who began to implement new and alternative methods of representing and reconstructing past events and memories, which leads to the renovation and diversification of shishi. With a combination of textual analysis and historical interpretation, this study shall examine the works of six writers with varied and distinctive features from the 1980s to the present and demonstrate their contribution to the continued relevance and vitality of shishi in Chinese literature. The final lesson is, instead of sustaining a static and definitive view of shishi, we should recognize and embrace its dynamic and plural natures, and its ability to adapt and innovate.

As an important part in the process of hydraulic fracturing, fracturing fluid flowback after fracturing will directly affect the productivity of the fractured wells. It is of great significance to carry out optimization research on the flowback working system of fracturing fluid (the time of flowback beginning and the size of flowback nozzles) to enhance the efficiency of fracturing. At present, researches on optimization model of fracturing fluid flowback have taken into account the effects of fracturing fluid loss and proppant reflux, while ignoring the effects of proppant sedimentation. A new calculation model of proppant regurgitation velocity has been established in recent years, but it is rarely used in the research of flowback working system. This study innovatively integrated the calculation model of modified proppant sedimentation velocity obtained through experiments, the new calculation model of critical proppant regurgitation velocity, and the wellhead pressure calculation model to form a comprehensive flowback model of fracturing fluid. Then coupled with the flowback criteria of quickly flowback, reducing proppant reflux, and maintaining proppant settlement degree (ratio of proppant settlement distance to crack height) less than 60%, an optimization model of fracturing fluid flowback is constructed and realized by MATLAB software programs. The optimization model were verified by four fractured wells in DaQing Oilfield. The effects of reservoir permeability, reservoir porosity, fracturing fluid density, and proppant particle size on wellhead pressure drop, fracturing fluid flowback rate, and proppant settlement degree were calculated and analyzed by using the above flowback model. The verification results show that the simulated wellhead pressure and flowback flowrate are in good agreement with the actual dataset, with the average errors of 11.9% and 11.6% respectively, which proves the accuracy of the flowback optimization model. Parametric analysis shows that, with the increase of reservoir permeability and reservoir porosity, the wellhead pressure drop velocity increases. When the permeability increases from 1mD to 5mD, the flowback rate of fracturing fluid and proppant settlement degree are reduced by 12.3% and 69.8% respectively. When the porosity increases from 9% to 36%, the proppant settlement degree fall by 25.2%. Moreover, the flowback rate of fracturing fluid decreases linearly and the proppant settlement degree increases linearly with the increase of fracturing fluid density; and the proppant settlement degree increases by 3.5 times when the proppant particle size increases from 0.25 mm to 1.65 mm. Therefore, choosing smaller fracturing fluid density and smaller proppant particle size can ensure higher fluid flowback efficiency and lower proppant settlement degree.