The primary focus of this thesis is to present a simple and practical implementation of an optimal-time response controller for multiphase interleaved dc-dc SMPS. This novel solution enables equal current sharing between phases not only in steady-state, but also during load transients, as well as bump-less transition between those two states. A digital voltage loop and multiple analog peak current programmed mode current loops are combined to implement a capacitor charge balance control algorithm with fairly simple hardware. This algorithm provides recovery from a disturbance in a single on-off switching action, which is performed in virtually the fastest possible time. The hybrid interface between the loops is provided through a structure combining a sample-and-hold circuit and a relatively slow successive-approximation DAC that provides control signals for all the loops in the system. Furthermore, for operation under light load conditions, the controller automatically switches into simply implemented pulse-frequency mode of operation.

Power-amplifier efficiency is a significant issue for the overall efficiency of most wireless system. Therefore, currently there are different kind of Switched mode power amplifiers are developed which are showing very high efficiency also at higher frequencies but all of these amplifiers are subjected to drive with the constant envelope signals. Whereas, for the increasing demand of high data rate transmissions in wireless communication there are some new modulation schemes are introduced and which are generating no more a constant envelope signal but a high peak to average power signal. Therefore, recently a new technique is proposed called the burst mode operation for operating the switched mode power amplifiers efficiently while driven by a high peak to average power signal.   The purpose of this master thesis work was to review the theory of this burst mode operation and some basic investigations of this theory on switched mode power amplifiers were performed in simulation environments. The amplifiers of class D, inverse D, DE and J are studied. The thesis work was mainly carried out by ADS and partly in MATLAB SIMULINK environment. Since this burst mode operation is a completely new technique therefore a new Harmonic balance simulation setups in ADS and Microwave Office are developed to generate the RF burst signals.   A Class J amplifier based on LDMOS technique is measured by a 16 carrier multi-tone signal having peak to average power ratio of 7 dB and achieved the drain efficiency of 50% with -30 dBc linearity at 946 MHz.

This thesis is an approach to improve a two-mode hybrid electric vehicle, which is currently under development by GM, with respect to fuel consumption. The study is not only restricted to the specific two-mode HEV but also presents results regarding parallel as well as serial HEV’s. GM whishes to verify if the online-based controller in the prototype vehicle utilizes the most of the HEV ability and if there is more potential to lower the fuel consumption. The purpose is that the results and conclusions from this work are to be implemented in the controller to further improve the vehicle’s performance. To analyze the behavior of the two-mode HEV and to see where improvements can be made, models of its driveline and components are developed with a focuson losses and efficiency. The models are implemented in MATLAB together with an optimization algorithm based on Dynamic Programming. The models are validated against data retrieved from the prototype vehicle and various cases with different inputs is set up and optimized over the NEDC cycle. Compensation for cold starts and NOx emissions are also implemented in the final model. Deliberate simplifications are made regarding the modeling of the power split’s functionality due to the limited amount of time available for this thesis. The optimizations show that there is potential to lower the fuel consumptionfor the two-mode HEV. The results are further analyzed and the behavior of the engine, motors/generators and battery are compared with recorded data from a prototype vehicle and summarized to a list of suggestions to improve fuel economy.

We comprehensively investigated the concentration effect of dispersed single-walled carbon nanotubes (SWCNTs) in polymer films for being a saturable absorber (SA) to stabilize the mode locking performance of the Erbium-doped fiber laser (EDFL) pulse through the diagnosis of its nonlinear properties of SA. The measured modulation depth was 1 to 4.5% as the thickness increased from 18 to 265 £gm. We obtained the stable pulse of the mode-locked EDFL (MLEDFL) when the full-width half-maximum (FWHM) decreased from 3.43 to 2.02 ps as the concentrations of SWCNTs SA increased from 0.125 to 0.5 wt%. At constant concentration of 0.125 wt%, the similar pulse shortening effect of the MLEDFL was also observed when the FWHM decreased from 3.43 to 1.85 ps was the thickness of SWCNTs SA increased from 8 to 100 £gm. In EDFL system, we vary group-velocity dispersion (GVD) with different cavity length to achieve optical pulse compression. We got the shortest pulsewidth was 713 fs, and the time-bandwidth product (TBP) was 0.345. An in-depth study on the stable mode-locked pulse formation employing SWCNTs SA, it is possible to fabricate the SWCNT films for use in high performance MLEDFL and utilization of many other low-cost nanodevices.

In this thesis, Rayleigh-mode and Sezawa-mode surface acoustic wave devices, and SMR-based (solidly mounted resonator, SMR) thin film bulk acoustic wave devices were employed to construct the UV sensors. The oscillators are composed of acoustic wave devices, high-frequency amplifier and matching networks. Due to the fact that the different acoustic wave devices are associated with the different propagating behaviors, electromechanical coefficient and resonance characteristics, they lead to the diversely sensing properties. Although Rayleigh-mode and Sezawa-mode SAW devices are both constructed by a ZnO sensing layer, they operate with different resonance behaviors and propagate with different phase velocities in the layered structures. Therefore, they result in different frequency shifts and sensitivities while illuminating UV light on the surface of ZnO thin films. As to the SMR device, the acoustic waves are confined within the ZnO piezoelectric layer sandwiched between two metal electrodes and then resonance as standing waves. In general, thin film bulk acoustic wave devices, which are SMR devices in this thesis, possess a higher operating frequency and better frequency response than those of SAW devices. Therefore, it is expected that UV sensors based on SMR devices will lead to an excellent performance. The Rayleigh-mode SAW-based UV sensors consisted of a 3£gm-thickness ZnO thin film for sensing UV light and a 2mm-thickness LiNbO3 substrate for generating surface acoustic waves in the ZnO/ LiNbO3 layered structure. Because surface acoustic waves travel along the surface within the depth of one wavelength, 32 £gm herein, most of them propagate in the LiNbO3 substrate. SAWs were perturbed slightly and consequently resulted in an unsatisfactorily maximum frequency shift of 63.75 kHz when a UV light intensity of 1250 £gW/cm2 was illuminated on the surface of ZnO thin film. Because ZnO films in this thesis are used as the sensing layer for UV light, we adjusted the sputtering parameter of deposition temperature to improve their crystalline properties and further enhance the sensitivity of ZnO/LiNbO3 layered SAW devices. Finally, the maximum frequency shift was raised to 264 kHz with the same UV light intensity using the deposition temperature of 400 ¢J. The ZnO thin films in the ZnO/Si layered structure were simultaneously employed as the piezoelectric layer for generating SAWs and the sensing layer for UV light. Therefore, all of the acoustic waves propagate within the ZnO thin films and are easier disturbed than the devices operated with the ZnO/LiNbO3 layered structure. This accounts for the relatively large frequency shift of 1017 kHz with the UV light intensity of 551 £gW/cm2. The ½ £f type SMR device was adopted to construct the UV sensor due to their better resonance characteristics than those of ¼ £f type. As can be seen from the results that SMR-based UV sensor presented better UV sensing properties compared with SAW-based UV sensors. The reasons for the considerable frequency shifts and sensitivities can be attributed to that SMR-based sensor possesses a shorter resonance wavelength and a larger electromechanical coefficient than those of SAW-based devices. Finally, the maximum frequency shift of 552 kHz can be obtained when the illumination intensity of UV light was 212 £gW/cm2.

In this thesis we use pulse shaping system to generate pulse train. Using empirical mode decomposition(EMD) and short-time Fourier transform(STFT) to analyze the signal of terahertz radiation. we use pulse shaping system to modulate the amplitude and phase of light which provide for pulse train generation. Compare with other method, first, our method will improve the stability of time delay control. Second this method is easier to control the time delay and number of pulse in the pulse train. In the past, people find the occur time of high frequency by observed the time domain of terahertz radiation directly, but if the occur time near the time of the peak power of terahertz radiation, we can¡¦t find out the occur time of high frequency. Using STFT can find out the relationship between intensity and time, but if the modes in signal have different width of frequency STFT have to use different time window to get the best frequency resolution and time resolution. However the time window with different width will have different frequency resolution, and the relationship between intensity and time will change with different frequency resolution, therefore using different frequency resolution will get different result, so we need a new signal analysis method. To solve this problem we use EMD to decompose different mode in the signal of terahertz radiation into different intrinsic mode function(IMF), and analyze the signal of terahertz by STFT to find the occur time of high frequency of terahertz radiation. Because the modes are separated in to different IMF, we can use STFT with the same time window. We expect this method applied to narrow-band frequency-tunable THz wave generation will be better.

The purpose of this thesis is to study the c-axis inclined ZnO films to produce dual-mode thin-film piezoelectric transducer. The cantilever beam vibration theory as a power generation mode in adopted to verify that the transducer is in suitable for the application in the environment for low-frequency vibration. In order to develop dual-mode thin-film piezoelectric transducer, this study uses radio-frequency magnetron sputtering method with off-axis growth to deposit ZnO films on Pt/Ti/stainless steel substrate(SUS304), the effects of deposition parameters on the characteristict of ZnO films are studied. Because zinc oxide thin-film is grown with c-axis tilt, so the piezoelectric transducer exhibits longitudinal-mode and shear-mode characteristics. The physical characteristics of ZnO thin films were obtained by the analyses of the scanning electron microscopy (SEM) and X-ray diffraction (XRD) to discuss the surfaces, cross section and crystallization of ZnO thin films. Finally, the vibration test equipment in used for the measurement of electrical properties. The open and loaded voltages of the transducers were obtained by the measurement system. The optimal deposition parameters for ZnO thin films are sputtering pressure of 5 mTorr, RF power of 150W, substrate temperature of room temperature and oxygen concentration of 50%, which were determined by physical characteristics and voltage analysis. Under the optimal parameters, the ZnO thin-films are deposited with maximum shear-mode and tilting angles of 35¢X.The transducer was one-sid loaded with a piece of metal of 0.5 g load to enhance the cantilever vibration amplitude. As the input vibration of 65 Hz and vibration amplitude of 1mm were set, the maximum output power was obtained. The maximum open circuit voltage of 19.4 V was obtained. When the output of the transducers was recetified and filtered through a 1NN5711 Schottky diode bridge rectifier and a 33nF capacitor, the maximum power of 2.05£gW/cm2 was achieved with the load resistance of 5M£[.

It is usually to see a large number of pipelines separating around the refineries, chemical and petro-chemical plants. The corrosion and erosion defects are unavoidable to occur in transporting pipe line. Especially, the maintain stuff usually find out breakage pipe or leaking liquid at elbowing pipe line because of the corrosion and erosion defects. So it is essential to examine these pipelines with an efficient method. The use of guided waves method is very attractive to solve this problem since guided wave could be excited at one circle on the pipeline and propagate over considerable distance. To choose guided wave torsion mode T (0, 1) as excitation mode because its group velocity doesn¡¦t change with frequencies. And the research analyzes the mode conversion that occurred when T (0, 1) mode propagated after the elbow pipe. The research also discusses the signal difference in different depth, circumferential distribution and axial length defects on the elbow pipe. The erosion defect usually occurs in the elbow pipe line and it would change with fluid velocity, causticity of fluid and flow direction. Therefore, the research designs the defects according to the character of erosion defect by finite element method software and simulates T (0, 1) mode propagating in the pipe line. Then this research extracts and analyzes the reflection signals from defects. In this guided wave experiment, the research manufactures the defect on elbow pipe. Because the erosion defect could be usually found at outer side of elbow pipe, artificial defect would be set there. And the elbow pipe is manufactured with different depth, circumferential distribution and axial length defect. The research would discuss the relationship between change of defect and reflection signal. By elbow pipe defect signals of simulation and experiment consequence, the different depth, circumferential distribution and axial length defect signals could be still distinguished. The signals with different axial length defect that received from straight pipe and elbow pipe are similar and are affected by signal constructive and destructive interference. So the research could get maximum and minimum defect signal amplitudes from one-fourth wavelength axial defect and half wavelength axial defect. Therefore, the axial length defect of elbow pipe could be estimated from defect signals and this consequence could help judge the level of damaged elbow pipe. T (0, 1) mode has better sensitivity to outside of the pipe than inside of the pipe. So the bigger signal amplitude could be received from the notch at outside of the pipe. In the process of wave propagation simulation, there are overlapping waveforms and mode conversions occur at elbow pipe. This situation causes the defect signals were amplified at elbow pipe. In practical detection, the misjudgments of amplified defect signals should be attended to.

This research investigated the characteristics of single-mode optical pulses generated with orthogonal-polarization optical feedback (OPF) in Fabry-Perot type semiconductor lasers. Single-mode pulse trains with a pulse frequency of 470 MHz and 3.76 GHz were observed. A modified model was proposed to solve the inconsistency between the experimental results and the computer simulations of Otsuka and Chern¡¦s model. These results also solve the problem of a round-trip feedback distance that is too short to enable the feedback system to be implemented, making this technology accomplishable in currently working systems. Furthermore, this investigation recovered and maintained a stable oscillation of every missing longitudinal mode in a hysteresis type mode-hopping gap of a semiconductor laser. A special feature of this method is that both the laser power and spectral purity are preserved during mode recovery and mode switching. The experimental results also reveal that the OPF effectively suppressed mode-hopping in semiconductor lasers and drove the laser into a stable single-mode state. Finally, this research employed OPF to suppress the intensity noise stimulated by coherent optical feedback in a semiconductor laser. At a coherent-feedback level as strong as ¡V14 dB, an OPF ratio of ¡V29 dB could return the laser to its primitive single mode from the multimode, yielding a spectral purity and relative intensity noise (RIN) even better than the solitary values. These discoveries constitute an important contribution to our understanding of applications of semiconductor lasers.

BACKGROUND Because the medical envirement continously progresses, all the people working in hospital or health department are concerned in the health issues. Although the Intergration Delivery System was used for management of respiratory care, but the medical quality still was suspected. Therefore, this study discusses what are the significantly related factors of plan or unplan extubation to elevate the quality of respiratory care. PURPOSE The purposes of this study are described bellow¡G 1.To predict the related factors of successful plan extubation. 2.To find the related factors of unplan extubation. 3.To discuss what are the causes of intubation. 4.To find the stand procedure of clinical path-way of ventilator weaning. MATERIAL This study collected data of ICU patient been used ventilator from october 2000 to october 2001. The method of analysis included Descriptive stastic analysis, Correlation, ANOVA, Stepwise regression, and Logistic regression. The data included characteristics of patient, clinical sign, ventilator setting, and the count of intubation days. RESULT 1.The plan extubation of conscious-clear patient is more successful than concious-unclear. 2.The successful extubation of CPPV mode is less than others. 3.Gender is a related factor of unplan extubation. 4.CO2 is postive correction with unplan extubation. 5.PSV mode is negative correction with unplan extubation. 6.CPPV mode is postive correction with unplan extubation. 7.Unplan extubation easily occurs in the early stage of intubation when the patient is unstable.