Late Iron Age Ceramic Manufacturing along the Maritsa River in the Northwestern Rhodope Mountains. A Characterization from Emporion Pistiros

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Characterization of Si-MOSFETs for Terahertz Detection: Development for a Potential Future Astrophysical Sensor Technology

Terahertz (THz) commonly refers to a region of the electromagnetic spectrum with frequencies ranging between 0.1 to 10 THz (wavelengths of 3 mm to 30 μm). The technology available for detection and generation in this spectral region has been less developed than in the adjoining infrared and visible domains. For the astronomy community, THz observation provides information related to various phenomena including, for example, the study of cosmic microwave background radiation (CMBR), emission from proto-planetary disks, and planetary atmospheric remote sensing. Many molecules have emission and absorption spectral features in the THz regime whose observation provides the ability to extract information on chemical composition, abundances, and environmental conditions. Current detector technology utilized for THz astrophysics typically utilizes bolometers or kinetic inductance devices (KIDs) that must be cooled and are available in limited array size. Detectors that could be operated in a fashion similar to that available in the visible, both in format and array size, would be very welcome. Bow-tie antenna-coupled silicon metal oxide semiconductor field effect transistors (Si-MOSFETs) have shown promise in detecting THz radiation for terrestrial applications. They have been fabricated in array formats and scaling to formats of interest to astronomers is straightforward. However, the characterization of such devices is insufficient to determine if they could be operated and optimized to be useful in some astronomical applications. This dissertation presents the characterization and analysis of such bow-tie antenna-coupled Si-MOSFETs designed for detection near 0.2 THz. Design parameters for the Si-MOSFETs, such as antenna size and source region, were varied in devices manufactured using MOSIS foundry access. These devices were extensively tested in this work to determine the fabrication parameters providing optimal performance. An exploration of the detection mechanism for the devices and its consistency with the characterization results will also be presented. This characterization will include a study of the nonlinearity of these devices with incident power. The detector sensitivity and noise requirements for a small-scale space mission will be discussed and compared to the devices tested. Finally, a discussion on potential future development for these detectors will be provided

Interaction Graphs: Full Linear Logic

Interaction graphs were introduced as a general, uniform, construction of dynamic models of linear logic, encompassing all Geometry of Interaction (GoI) constructions introduced so far. This series of work was inspired from Girard's hyperfinite GoI, and develops a quantitative approach that should be understood as a dynamic version of weighted relational models. Until now, the interaction graphs framework has been shown to deal with exponentials for the constrained system ELL (Elementary Linear Logic) while keeping its quantitative aspect. Adapting older constructions by Girard, one can clearly define "full" exponentials, but at the cost of these quantitative features. We show here that allowing interpretations of proofs to use continuous (yet finite in a measure-theoretic sense) sets of states, as opposed to earlier Interaction Graphs constructions were these sets of states were discrete (and finite), provides a model for full linear logic with second order quantification

Development of carbon based optically transparent electrodes from pyrolyzed photoresist for the investigation of phenomena at electrified carbon - solution interfaces

The work presented herein describes fundamental investigations of carbon as electrode material by using the pyrolysis of photoresist to create an optically transparent material. The development of these carbon-based optically transparent electrodes (C-OTEs) enables investigations of molecular interactions within the electrical double layer, processes that are central to a wide range of important phenomena, including the impact of changes in the surface charge density on adsorption [1].;The electrochemical importance of carbon cannot be understated, having relevance to separations and detection by providing a wide potential window and low background current in addition to being low cost and light weight [2, 3]. The interactions that govern the processes at the carbon electrode surface has been studied extensively[2, 3]. A variety of publications from the laboratories of McCreery and Kinoshita provide in depth summaries about carbon and its many applications in electrochemistry.[2-4] These studies reveal that defects, impurities, oxidation, and a variety of functional groups create adsorption sites on carbon surfaces with different characteristics [1-4].;Our interest in C-OTEs was sparked by the desire to study and understand the behavior of individual molecules at electrified interfaces. It draws on our earlier development of Electrochemically Modulated Liquid Chromatography (EMLC) [5-10], which uses carbon as the stationary phase. EMLC takes advantage of changing the applied potential to the carbon electrode to influence the retention behavior of analytes. However, perspectives gained from, for example, chromatographic measurements reflect the integrated response of a large ensemble of potentially diverse interactions between the adsorbates and the carbon electrode. Considering the chemically and physically heterogeneous surface of electrode materials such as glassy carbon [3, 11], the integrated response provides little insight into the interactions at a single molecule level. To investigate individual processes, we have developed C-OTEs in order to couple electrochemistry with single molecule spectroscopy (SMS).;Like EMLC, the novel merger of SMS with electrochemistry is a prime example of how a hybrid method can open new and intriguing avenues that are of both fundamental and technological importance. We show that by taking the benefits of total internal reflection fluorescence microscopy (TIRFM) and incorporating carbon as electrode material observations central to the interactions between single DNA molecules and an electrified carbon surface can be delineated.;Using TIRFM while applying a positive potential to the electrode, individual molecules can be observed as they reversibly and irreversibly adsorb to the carbon surface. The positive potential attracts the negatively charged DNA molecules to the electrode surface. Dye labels on the DNA within the evanescent wave are excited and their fluorescence is captured by an intensified charge coupled device (ICCD) camera. Results are therefore presented regarding the interactions of lambda-DNA, 48,502 base pairs (48.5 kbp), HPV-16, 7.9 kbp, and a 1 kbp fraction of pBR322 DNA. In addition to the influence of molecular size on adsorption, the fabrication, characterization, and more conventional spectroelectrochemical applications of these novel C-OTEs are presented