No description available.

Large trucks may have an integrated microwave oven, or a driver may add oneas a standalone solution, to allow heating food during long-haul transports. If a crash occurs with an item inside the oven, it may thrust against the door with such force that it opens from the inside. The goal of this thesis work is to develop a concept for a universally applicable solution that prevents flying parts from within the oven on a crash, as that presents a safety hazard for anyone inside the cabin. The thesis work was conducted according to a stage gate process, which included four phases: Context, Ideation, Concept Development, and Concept Design. It includes interviews, company visits, literature searches, design methodology, concept comparisons and computer aided design. The thesis work concludes with three concepts, all of which are locking solutions that are applied externally onto a microwave oven. They include a bolt latch, a solenoid lock, and a bolt latch integrated with the oven’s door button. All solutions traverse the transition area between door and panel.

Monolithic passively mode-locked colliding pulse semiconductor lasers generating pico- to sub-picosecond terahertz optical pulse trains are promising sources for future applications in ultra-high speed data transmission systems and optical measurements. However, in the absence of external synchronization, these passively mode-locked lasers suffer from large amplitude and timing jitter instabilities resulting in broad comb linewidths, which precludes many applications in the field of coherent communications and signal processing where a much narrower frequency line set is needed. In this dissertation, a novel quantum dot based coupled cavity laser is presented, where for the first time, four-wave mixing (FWM) in the monolithically integrated saturable absorber is used to injection lock a monolithic colliding pulse mode-locked (CPM) laser with a mode-locked high-Q ring laser. Starting with a passively mode-locked master ring laser, a stable 30 GHz optical pulse train is generated with more than 10 dB reduction in the RF noise level at 20 MHz offset and close to 3-times reduction in the average optical linewidth of the injection locked CPM slave laser. The FWM process is subsequently verified experimentally and conclusively shown to be the primary mechanism responsible for the observed injection locking. Other linear scattering effects are found to be negligible, as predicted in the orthogonal waveguide configuration. The novel injection locking technique is further exploited by employing optical hybrid mode-locking and increasing the Q of the master ring cavity, to realize an improved stabilization architecture. Dramatic reduction is shown with more than 14-times reduction in the photodetected beat linewidth and almost 5-times reduction in the optical linewidth of the injection locked slave laser with generation of close to transform limited pulses at ~ 30 GHz. These results demonstrate the effectiveness of the novel injection locking technique for an all-on-chip stability transfer and provides a new way of stabilizing monolithic optical pulse sources for applications in future high speed optical networks.

No description available.

This thesis discusses low-power wireline receivers with particular focus on clocking circuitry and architectures. These clocking solutions can be used for a 1-D partial response channel as well as for a conventional DC coupled channel. The receiver front end for a 1-D channel requires more consideration to recover an NRZ signal from the received narrow pulses. Two possible solutions are presented. First, a full-rate detection technique is presented, where the speed is limited by the settling time of a latch circuit which has to be less than 1 UI. Second, a novel demuxing technique is introduced. It is demonstrated through theory, simulation and measurement results that the half-rate architecture can improve maximum achievable speed by a factor of 1.6. The distribution and alignment of high-frequency clocks across a wide bus of links is a signi¯cant challenge in modern computing systems. A low power clock source is demonstrated by incorporating a bu®er into a cross-coupled oscillator. Because the load is isolated from the tank, the oscillator can directly drive 50-Ohm impedances or large capacitive loads with no additional bu®ering. Using this topology, a quadrature VCO (QVCO) is implemented in 0.13 um digital CMOS. The QVCO oscillates at 20 GHz, consumes 20 mW and provides 12% tuning range. Injection locked oscillators (ILOs) are an attractive clocking tool for low-power area- e±cient wireline receivers. In this work, we explored their use as a clock deskew element, a clock recovery unit and a programmable jitter lter. A study of both LC and ring ILOs indicates signi¯cant variation in their jitter tracking bandwidth when used to provide large phase shifts. By selectively injecting di®erent phases of a quadrature-LC or ring VCO, this problem is obviated resulting in reduced phase noise. First, an ILO based half-rate clock recovery technique is presented, which can be used for AC coupled links where low frequency signal components are attenuated by the channel. The nonlinear path comprises a hysteresis latch that recovers the missing low frequency content and a linear path that boosts the high frequency component by taking advantage of the high pass channel response. By optimally combining them, the front-end recovers NRZ signals up to 13 Gb/s burning only 26 mW in 90 nm CMOS. A simple theory and simulation technique for ILO-based receivers is discussed. The clock recovery technique is veried with experimental results at 5-10 Gb/s in 90 nm CMOS consuming 70 mW and acquiring lock within 1.5 ns. Second, a clock forwarded 65nm CMOS receiver uses two ILOs to frequency- multiply, deskew, and track correlated jitter on a pulsed clock forwarded from the transmitter. Di®erent data rates and latency mismatch between the clock and data paths are ac- commodated by a jitter tracking bandwidth that is controllable up to 300MHz. Each receiver consumes 0.92 pJ/bit operating at 7.4 Gb/s and has a jitter tolerance of 1.5 UI at 200MHz.

This thesis discusses low-power wireline receivers with particular focus on clocking circuitry and architectures. These clocking solutions can be used for a 1-D partial response channel as well as for a conventional DC coupled channel. The receiver front end for a 1-D channel requires more consideration to recover an NRZ signal from the received narrow pulses. Two possible solutions are presented. First, a full-rate detection technique is presented, where the speed is limited by the settling time of a latch circuit which has to be less than 1 UI. Second, a novel demuxing technique is introduced. It is demonstrated through theory, simulation and measurement results that the half-rate architecture can improve maximum achievable speed by a factor of 1.6. The distribution and alignment of high-frequency clocks across a wide bus of links is a signi¯cant challenge in modern computing systems. A low power clock source is demonstrated by incorporating a bu®er into a cross-coupled oscillator. Because the load is isolated from the tank, the oscillator can directly drive 50-Ohm impedances or large capacitive loads with no additional bu®ering. Using this topology, a quadrature VCO (QVCO) is implemented in 0.13 um digital CMOS. The QVCO oscillates at 20 GHz, consumes 20 mW and provides 12% tuning range. Injection locked oscillators (ILOs) are an attractive clocking tool for low-power area- e±cient wireline receivers. In this work, we explored their use as a clock deskew element, a clock recovery unit and a programmable jitter lter. A study of both LC and ring ILOs indicates signi¯cant variation in their jitter tracking bandwidth when used to provide large phase shifts. By selectively injecting di®erent phases of a quadrature-LC or ring VCO, this problem is obviated resulting in reduced phase noise. First, an ILO based half-rate clock recovery technique is presented, which can be used for AC coupled links where low frequency signal components are attenuated by the channel. The nonlinear path comprises a hysteresis latch that recovers the missing low frequency content and a linear path that boosts the high frequency component by taking advantage of the high pass channel response. By optimally combining them, the front-end recovers NRZ signals up to 13 Gb/s burning only 26 mW in 90 nm CMOS. A simple theory and simulation technique for ILO-based receivers is discussed. The clock recovery technique is veried with experimental results at 5-10 Gb/s in 90 nm CMOS consuming 70 mW and acquiring lock within 1.5 ns. Second, a clock forwarded 65nm CMOS receiver uses two ILOs to frequency- multiply, deskew, and track correlated jitter on a pulsed clock forwarded from the transmitter. Di®erent data rates and latency mismatch between the clock and data paths are ac- commodated by a jitter tracking bandwidth that is controllable up to 300MHz. Each receiver consumes 0.92 pJ/bit operating at 7.4 Gb/s and has a jitter tolerance of 1.5 UI at 200MHz.

Metallosupramolecular self-assembly has fast expanded as a field due to the possibility for relatively facile construction of large assemblies through reversible non-covalent interactions, compared to their more synthetically challenging covalent counterparts. Not least, it provides a fast and often quantitative route to the construction of three-dimensional structures with a cavity. These internal spaces have been shown to be effective for a variety of applications, including but not limited to catalysis, drug delivery, use as a noncovalent protecting group, a separations material etc. Thermodynamic processes, with the inherent advantages of atom efficient, high-yielding reactions, usually control these systems. However this can also be a double-edged sword, with these systems susceptible to changes to specific ambient conditions, and are thus often not kinetically stable. Herein, we report the expansion of a method utilising the one electron oxidation of high spin d7 cobalt(II) to low spin d6 cobalt(III) as a molecular locking mechanism as part of the assembly process. This allows for the formation of species under thermodynamic control in the CoII manifold, with the kinetic stability of these assemblies in the oxidised CoIII and has been used to synthesise a variety of tetrahedra and helicates with a series of bis-bidentate N,N’-chelate ligands, which have shown to be stable away from their thermodynamically preferred conditions for long periods of time. These containers can be made both water and organic soluble via counteranion exchange, and a series of guests have been shown to bind in the tetrahedral species. Alongside on going biological viability tests, these guests show promise for a variety of applications including fluorescent tagging and radio-diagnostic agents. Novel switching methods have also been demonstrated for transformations between these species going both energetically down and up hill.

The detection for phase locking in a forced oscillator with dual attractors and ill-defined phase structure is hard until a quantitative approach was constructed for detecting phase locking via stroboscopic method. We study the route to weak phase locking in a chaotic system ¡§Chua oscillator¡¨ with complex attractor structure by analyzing the stroboscopic points. The onset of weak phase locking detected by using this statistical approach and the critical coupling strength calculated by conditional Lyapunov exponent are matched well. Detailed structure of phase locking intensity is described by the Arnold tongue diagram. Moreover, we apply this approach on three hyper-chaotic systems with multi-scroll attractor, including hyper-chaotic Rössler system, hyper-chaotic Lorenz system, and modified MCK oscillator. The weak phase locking between hyper-chaotic system and a periodic or a chaotic driving force is observable following the condition of stroboscopic point concentration.

This thesis endeavors to develop a new locking method for a twisted morphing wing spar. The conventional wing has to have hinges and a discontinuous surface. These cause air separation that decreases aerodynamic performance. Unlike this old concept, the new airfoil comprises a square cross section spar into the wing blade. Twisting the spar changes the airfoil?s angle of attack to control lifting and thrust force without a discontinuous surface. A nastic actuator generates shear stress for twisting the spar. A thermoplastic polymer locks the twisted shape. Applying heat and solidifying the polymer makes the beam lock into the twisted position even after removing the shear stress. This concept was evaluated by computer simulation and an experiment with a prototype construction. The analysis with 5m long spar shows that +450Pa shear stress generated +2 degrees twist and maximum 1.49MN/m spring constant at the spar tip. This spring constant helps a designer select the locking material, Ultem. The analysis proves that the Ultem film?s shear spring constant is high enough to hold the aluminum spar?s spring back. Physical experiment conditions might differ from computer simulation because environmental limitations might be present. The prototype spar has to be less than 300mm long to fit in an electric oven. Tension made the beam twist and baked it with locking material. When the polymer softened, the beam was taken from the oven and cooled. The solidified locking material held the spar at twisted status. The observation shows no detectable spring back after removing tension. Analytic solution also presents no spring back in twisting the prototype section spar. The FEA of the section spar verifies the physical experiment results. As a normal polymer, the Ultem shows stress relaxation. The load drop affects deceasing elastic modulus. Subsequently, the Ultem is able to lock the twisted spar even after the relaxation.

Quadrature LO signal is a key element in many of the RF transceivers which tend to dominate today’s wireless communication technology. The design of a quadrature LC VCO with better phase noise and lower power consumption forms the core of this work. This thesis investigates a coupling mechanism to implement a quadrature voltage controlled oscillator using indirect injection method. The coupling network in this QVCO couples the two LC cores with their super-harmonic and it recycles its bias current back into the LC tank such that the power consumed by the coupling network is insignificant. This recycled current enables the oscillator to achieve higher amplitude of oscillation for the same power consumption compared to conventional design, hence assuring better phase noise. Mathematical analysis has been done to study the mechanism of quadrature operation and mismatch effects of devices on the quadrature phase error of the proposed QVCO. The proposed quadrature LC VCO is designed in TSMC 0.18 μm technology. It is tunable from 2.61 GHz - 2.85 GHz with sensitivity of 240 MHz/V. Its worst case phase noise is -120 dBc/Hz at 1 MHz offset. The total layout area is 1.41 mm^2 and the QVCO core totally draws 3 mA current from 1.8 V supply.