Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 15 of 15 for “"Frequency detuning"”.
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Energy Harvesting toward the Vibration Reduction of Turbomachinery Blades via Resonance Frequency Detuning
… blade vibrations, namely resonance frequency detuning. In contrast with the bulk of energy harvesting research, this effort is not focused on maximizing the power output of the system, but rather providing the low power levels required by resonance frequency detuning. The demands of …
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Determination of Frequency-Based Switch Triggers for Optimal Vibration Reduction via Resonance Frequency Detuning
Resonance frequency detuning (RFD) is a piezoelectric-based vibration reduction approach that applies to systems experiencing transient excitation through the system*s resonance—for example, turbomachinery experiencing changes in rotation speed, such as on spool-up and spool-down. This technique …
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Numerical investigation of the fluidelastic instability of two-phase flow in a parallel triangular tube array
… region, they are not tuned to a single natural frequency, a case known as frequency detuning. The presented work inspects the effect of frequency detuning and the key parameters controlling its influence. In this study, a model based on Computational Fluid Dynamics was proposed to simulate the …
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Injection Current Modulated Parity-Time Symmetry in Coupled Semiconductor Lasers
… spatial separation between the two lasers, the frequency detuning, and the coupling strength. We find that the experimental data agrees with the predictions from the theoretical model confirming the intensity behaviors of the lasers, and the monotonic change in PT-threshold as a function of …
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Numerical modeling of nonlinear mode interaction in semiconductor lasers and amplifiers to generate slow/fast light
… complex permittivity of the probe wave, if the frequency detuning between the two waves falls into the spectral range of parametric interaction. Consequently, in the vicinity of a strong driving wave (mode), the optical parameters such as the phase index, group index, linewidth, and the gain of …
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Performance characteristics on patch antenna with sar reduction using artificial magnetic conductor (amc) for wban applications
… better performance antenna for less impact of frequency detuning, by improving FBR, high radiation efficiency and reduce SAR for WBAN application. Conventional patch antennas are adopted since they can be low weight, low profile and easy to integrate with the device. Having these unique …
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Comparative Study of Forward and Diffusely Scattered Light in a Coherently Prepared Ultracold Rubidium Gas
… length, control field intensity, and probe field frequency detuning. Storage and retrieval of slow light pulses was achieved for the forward scattering (transmission) channel, but was not observed unambiguously in the diffusely scattered (fluorescence) channel.</p>
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Synchronization in Coupled Opto-thermal Silicon MEMS Limit Cycle Oscillators
… cycle oscillations, self-synchronization, and frequency entrainment to an external drive. In this work, we chart the behavior of silicon MEMS oscillators that are nominally 40 µm long and 205 nm thick, mechanically coupled, and opto-thermally driven by a continuous-wave helium-neon laser. …
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Properties and applications of the photorefractive material Ce:KNSBN
… than that by the argon-ion laser. The Doppler frequency detuning technique is first, to our knowledge, applied in the SPPC CAT configuration. The SPPC reflectivity is enhanced and the uniformity of the reflectivity is improved by this technique.
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Coherent two photon excitation within an extended cloud of Rubidium 85 for the purposes of atomic interferometry and cooling
… offer advantages such as insensitivity to frequency detuning or a higher number of photon momenta which can be imparted for each spontaneous emission event making them promising candidates for the optical cooling of particles with more general energy level structures. In order to …
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Analysis and practical considerations in implementing multiple transmitters and receivers for wireless power transfer via coupled magnetic resonance
… resonant coil coupling is also shown. Resonant frequency detuning due to nearby metallic objects is observed and the extent of how much tuning can be done is demonstrated. A practical power line synchronization technique is proposed to synchronize all transmit coils. This reduces additional …
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Enhanced Modulation Dynamic Performance of Optically-Injected Widely-Tunable Semiconductor Lasers
… in terms of the achievable speed and improved frequency chirping behaviour under the direct modulation regimes using external light for optical injection-locking (OIL). It is demonstrated that modulation performance of free running (FR) widely tunable lasers strongly depends on the tuned lasing …
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Non-Hermitian Whispering Gallery Mode Optical Microresonators and Their Applications
… communications, microlasers, opto-mechanics, frequency comb, and cavity quantum electrodynamics. Recently, WGM microresonators have proven to be an excellent platform to study non-Hermitian physics, due to the ease with which non-Hermiticity can be controlled via gain-loss distribution and …
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Computations of fully nonlinear three-dimensional wave-body interactions
… we identify that the second-order difference-frequency interaction between surface waves and body motions is the key mechanism for the excitation of unstable resonant motions. Fully nonlinear simulations are conducted to study the development of large-amplitude body motions and investigate …
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Wireless, Battery-Free, High-Sensitivity 5G RF Energy Harvesters for Next Generation IoT Sensor Tags
… various energy-harvesting technologies, radio frequency (RF) energy harvesting has emerged as a promising solution for powering IoT devices. By harvesting energy from ambient RF signals in licensed frequency bands, RF energy-harvesting systems eliminate the need for batteries and allow for …