This dissertation describes experimental studies of the superconducting proximity effect in single-crystal Pb, Sn, and Zn nanowires of lengths up to 60 um, with both ends of the nanowires in contact with macroscopic electrodes that are either superconducting (Sn or Pb) or non-superconducting (Au). The Pb, Sn, and Zn nanowires are fabricated using a template-based electrochemical deposition method. Electric contacts to the nanowires are formed in situ during electrochemical growth. This method produces high transparency contacts between a pair of macroscopic electrodes and a single nanowire, circumventing the formation of oxide or other poorly conducting interface layers. Extensive analyses of the structure and the composition of the nanowire samples are presented to demonstrate that (1) the nanowires are single crystalline and (2) the nanowires are clean without any observable mixing of the materials from the electrodes. The nanowires being investigated are significantly longer than the nanowires with which electrode-induced superconductivity was previously investigated by other groups. We have observed that in relatively short (~6 um) Sn and Zn nanowires, robust superconductivity is induced at the superconducting transition temperatures of the electrodes. When Sn and Pb nanowires are in contact with a pair of Au electrodes, superconductivity is suppressed completely. For nanowires of 60 um in length, although the suppression of superconductivity by Au electrodes is only partial, the induced superconductivity at the higher transition temperatures of the electrodes remains full and robust. Therefore, an anomalous superconducting proximity effect has been observed on a length scale which far exceeds the expected length based on the existing theories of the proximity effect. The measured current-voltage characteristic of the nanowires reveals more details such as hysteresis, multiple Andreev reflection, and phase-slip centers. An interesting relation between the proximity effect and the residual-resistance-ratio of the nanowires has also been observed. Possible mechanisms for this proximity effect are discussed based on these experimental observations.

In this paper, single mode buried optical waveguides based on hybrid sol-gel glasses and PECVD oxide were fabricated. Two different buried waveguide devices are investigated, and their optical characteristics are characterized. The first buried waveguide was obtained by etching a shallow trench on SiON layer. Then sol-gel material used as the guiding layer was deposited onto the layer and cured in proper conditions. Finally, the waveguides were completed by coating a sol-gel top cladding layer onto the guiding layer. The propagation loss of the waveguide is 0.59dB/cm at £f=1310nm. The second buried waveguide was fabricated by etching a trench of 5£gm on SiON layer and then burying sol-gel material into the trench.Proximity printing was used to define the waveguide core on sol-gel films.The waveguide was packaged for measurement after coating a UV glue on top of the core layer. The propagation losses of this waveguide device are 0.6dB/cm and 0.57dB/cm for TE and TM polarized lights. The coupling losses are 2.21dB and 2.41dB for TE and TM lights.

The Switched Reluctance Motor (SRM) inherits a simple and reliable structure with an economical manufacturing cost. The DC power output supplies the unipolar converter to control the pulses sent to SRM. Thus, the velocity and torque are controllable for various velocity commands, and the SRM is gaining more and more applications on high torque requirement field with constant power. This paper proposes a DSP based hybrid sensor for switched reluctance motor with easy implementation. The current transducer is used to monitor the energized current and proximity sensors for rotor salient. The signals are then fed back to DSP. This design will improve the performance of SRM to operate more smoothly.

Robertson and Bowlby (1952) found that prolonged separations from the mother lower the extent to which infants seek proximity to their mother. Although prolonged separations are no longer common today, some infants experience extremely long hours of nonmaternal care, which may lead them to seek less proximity to their mother. I examined this hypothesis using data from the National Institute of Child Health and Development: Early Child Care and Youth Development Study (N = 1,281). A series of regression analyses revealed that infants’ hours of nonmaternal care at 4 to 6, 7 to 9, and 10 to 12 months, but not at 1 to 3 or 13 to 15 months, were associated with their proximity-seeking behavior in the Strange Situation at 15 months. Using a polynomial regression analysis, I further found a cubic relation between the number of nonmaternal care hours at 7 to 9 months and infants’ proximity-seeking behavior. Specifically, proximity-seeking behavior rapidly declined during two time periods: when infants spent from 0 to 10 hours per week in nonmaternal care and when they spent over 60 hours per week in nonmaternal care. I also found that mothers’ and nonmaternal caregivers’ sensitivity was associated with infants’ proximity-seeking behavior, and proximity-seeking behavior predicted young children's ability to control their behavior and also the amount of time that they were able to focus their attention on their mother or their experimenter during a developmentally challenging task at 36 months. Findings reported in this dissertation highlight the important role of proximity-seeking behavior in the attachment relationship formed with the caregiver during infancy and the development of self-control and attention during the preschool years. / text

First discovered by Holm and Meissner in 1932, the superconducting proximity effect has remained a subject of experimental and theoretical interest. In recent years, it has been proposed that proximity effect in a semiconductor with large g-factor and spin-orbit coupling could lead to exotic phases of superconductivity. This thesis focuses on proximity effect in one of the prime semiconductor candidates -- InAs nanowires. The first set of experiments investigates the superconducting phase-dependent tunneling spectrum of a proximitized InAs quantum dot. We observe tunneling resonances of Andreev bound states in the Kondo regime, and induce quantum phase transitions of the quantum dot ground state with gate voltage and phase bias -- the latter being the first experimental observation of its kind. An additional zero-bias peak of unknown origin is observed to coexist with the Andreev bounds states. The second set of experiments extends upon the first with sharper tunneling resonances and an increase in the device critical field. By applying an external magnetic field, we observe spin-resolved Andreev bound states in proximitized InAs quantum dots. From the linear splitting of the tunneling resonances, we extract g-factors of 5 and 10 in two different devices. The third set of experiments utilizes a novel type of epitaxial core-shell InAs-Al nanowire. We compare the induced gaps of these nanowires with control devices proximitized with evaporated Al films. Our results show that the epitaxial core-shell nanowires possess a much harder induced gap -- up to two orders of magnitude in sub-gap conductance suppression as compared to a factor of five in evaporated control devices. This observation suggests that roughness in S-N interfaces plays a crucial role in the quality of the proximity effect. The fourth set of experiments investigates the gate-tunability of epitaxial half-shell nanowires. In a half-shell nanowire Josephson junction, we measure the normal state resistance, maximum supercurrent, and magnetic field-dependent supercurrent interference patterns. The gate dependences of these independent experimental parameters are consistent with one another and indicate that an InAs nanowire in good ohmic contact to a thin sliver of Al retains its proximity effect and is gate-tunable. / Physics

We present three criteria for compactness in the context of apartness spaces and Bishop-style constructive mathematics. Each of our three criteria can be summarised as requiring that there is a positive distance between any two disjoint closed sets. Neat locatedness and the product apartness give us three variations on this theme. We investigate how our three criteria relate to one another and to several existing compactness criteria, namely classical compactness, completeness, total boundedness, the anti-Specker property, and Diener's neat compactness.

Every year, more than a million people are diagnosed with colorectal cancer (CRC) that develops in the large intestine. It is one of the most studied cancers in the world but still more knowledge about how this cancer develops and acts is needed in order to use more effective ways to treat CRC. Autophagy is a vital mechanism in cells that is also suggested to maintain cancer cell survival. In normal cells, it plays an important role by removing damaged cells and organelles as well as eliminating pathogens. Under metabolic stress this mechanism is induced to provide enough nutrients and energy for the cell to survive. Cancer cells are exposed to greater environmental stress than normal cells and therefore, cancer cells exhibit higher levels of autophagy suggesting it to be a crucial mechanism for their survival. Gaining a deeper understanding of this essential mechanism and its activation might provide new insights and improved treatments for the fight against colorectal cancer. In situ Proximity Ligation Assay (PLA) is a protein detection method that enables sensitive and specific detection of proteins and protein-protein interactions (PPIs) in cell lines and tissue samples. The method uses simultaneous recognition of two independent antigens on a protein or protein complex together with a rolling circle amplification (RCA) to form a rolling circle product (RCP) on top of the target. By using fluorescent oligonucleotides, RCP can be visualized and is seen as a bright spot that enables sensitive detection of the target at single-molecule resolution. The aim of this study was to develop assays to detect endogenous molecular events known to be biomarkers of autophagy in situ in order to study autophagy mechanism in CRC patient samples. We focused our research on two PPIs that were known to interact when autophagy is induced. The first investigated interaction was between microtubule-associated protein 1A/1B- light chain 3 (LC3) and sequestome-1 (SQSTM1), an interaction that occurs during autophagy initiation. The second interaction was between B-cell lymphoma 2 (Bcl-2) and Bcl-2/adenovirus E1B 19-kDa interacting protein 3 (BNIP3) that takes place during hypoxia-induced autophagy. To study whether these PPIs can be used as a detection method to monitor autophagy, we used a well- established cell model based on serum starvation and CoCl2 - an hypoxic mimetic- treatment of the intestinal cancer cell line Caco-2 in comparison to normal culture condition. According to isPLA quantification, detection of both PPIs was distinctly higher in treated cells compared to untreated cells giving promising results and suggesting that they can be potentially used as suitable assays to monitor these biomarkers of autophagy. For development of an improved protein detection method that enables the study of several PPIs simultaneously in a tissue sample (In situ Multiplexing), we conjugated directly a short oligonucleotide strand to the primary antibodies. These formed proximity probes could later be used in in situ for multiplexing.

In the "Internet of Things" (IoT), the things will be able to sense, communicate, and interact. They will also exchange data, information and knowledge, and locate themselves and other things that surround them. In order to be able to interact, the things need to recognize that they are in proximity of other things. It is anticipated that the most widespread components of the IoT will be passive radio frequency identification (RFID) tags because they are inexpensive and provide automatic identification. However, passive RFID tags are not capable of performing complex operations, such as proximity detection and localization, which will be required in future networks. In this thesis, we describe existing problems with current RFID systems and survey potential solutions for localization and proximity detection. Then we present a new RFID device called "Sense-a-Tag" (ST) that can passively detect and decode backscattered signals from tags in its proximity. There have already been an attempt to use this device for tracking. However, detailed analysis of the performance of the ST especially for proximity detection has not been performed yet. We show that when STs are added to a standard RFID system, the problems of proximity detection and localization with RFID tags can readily be solved. Then we applied ST-based system for identifying people and object interactions. The potential uses of ST as an augmented device for IoT applications are discussed in this thesis. Advantages and limitations of an ST based RFID system have been investigated in details for each application. Results obtained from real experiments illustrate that an ST-based RFID system is feasible for proximity detection applications. In addition, a special software is developed in C\# to process the data and run a localization algorithm based on proximity detection information. The same software has been used for tracking people's activity. Different scenarios have been considered in the experiments. We tried to consider majority of factors that might affect the accuracy in the experiments including: angle and distance between the reader/ST and tags, timing in sending queries, presence of human body, etc. The simulations based on real experiments and results illustrates that an ST-based RFID system can be a realistic solution for proximity detection and localization for Location Positioning systems (LPS) and activity monitoring in future IoT.

Zugl.: Stuttgart, Univ., Diss., 2005

Regensburg, Univ., Diss., 2008.