In this thesis, we investigated charge carrier properties of two series of organic semiconductors with time of flight measurement. Charge carrier mobility is calculated in different electron filed and fitted to Poole-Frenkel model. In the first part, we investigated carrier properties of pyrrole derivatives .The mea- surement result of pyrrole derivatives with different functional group indicate that trans- port properties may effected by this different functional group and the bonding position. There have two different type of transport properties that is single transport and bipolar transport. In addition, carrier mobility have more than two order difference with this different functional group. Finally, we investigated carrier properties of anthracene derivatives. The measure- ment result indicate that the intermolecular aggregation can be solved by synthesizing another functional group to form polymer. This method not only perform excellent thin film stability but also keep bipolar transport property after synthesizing.

The aromatic amino acid hydroxylases phenylalanine hydroxylase (PheH), tyrosine hydroxylase (TyrH) and tryptophan hydroxylase (TrpH) utilize tetrahydropterin and molecular oxygen to catalyze aromatic hydroxylation. All three enzymes have similar active sites and contain an iron atom facially coordinated by two histidines and a glutamate. The three enzymes also catalyze the benzylic hydroxylation of 4- methylphenylalanine. The intrinsic primary and ?-secondary isotope effects for benzylic hydroxylation and their temperature dependences are nearly identical for the three enzymes, suggesting that the transition states, the tunneling contributions and the reactivities of the iron centers are the same. When molecular oxygen and the tetrahydropterin are replaced by hydrogen peroxide (H2O2), these enzymes catalyze the hydroxylation of phenylalanine to form tyrosine and meta-tyrosine with nearly identical second order rate constants. When the H2O2-dependent reaction is carried out with cyclohexylalanine or 4-methylphenylalanine, the products are 4-HO-cyclohexylalanine and 4-hydroxymethylphenylalanine, respectively. These experiments provide further evidence that the intrinsic reactivities of the iron centers in these enzymes are the same. Wild-type PheH and the uncoupled mutant protein V379D exhibit normal and inverse isotope effects, respectively, with deuterated phenylalanines. When the reaction is monitored by stopped-flow absorbance spectroscopy, three steps are visible. The first step is the reversible binding of O2, the second step is 5-7 fold faster than the turnover number, setting a limiting value for the rate constant for O2 activation, and the last step is non-enzymatic. There is no burst in the pre-steady state formation of tyrosine. These results are consistent with formation of the new C-O bond to form tyrosine as the ratelimiting step of the reaction. The reaction of TrpH with both tryptophan and phenylalanine was studied by stopped-flow absorbance spectroscopy and rapid-quench product analysis. With either amino acid as substrate, four steps can be distinguished. The first step is the reversible binding of O2 to the Fe(II) center; this results in an absorbance signature with a maximum at 420 nm. This O2 complex decays with a rate constant that is 18-22 fold faster than the turnover number with either amino acid, setting a the lower limit for the rate constant for O2 activation. The rate constant for the third step agrees well with the pre-steady state of formation of 5-hydroxytryptophan or tyrosine from rapid-quench product analysis. The rate constant for the fourth step agrees well with the turnover number. Overall, these results show that O2 activation is fast and turnover with each amino acid is limited by hydroxylation and release of a product, with the former step being about 4-fold faster than the latter.

Low drop out (LDO) voltage regulators are widely used for post regulating the switching ripples generated by the switched mode power supplies (SMPS). Due to demand for portable applications, industry is pushing for complete system on chip power management solutions. Hence, the switching frequencies of the SMPS are increasing to allow higher level of integration. Therefore, the subsequent post-regulator LDO must have good power supply rejection (PSR) up to switching frequencies of SMPS. Unfortunately, the conventional LDOs have poor PSR at high frequencies. The objective of this research is to develop novel LDO regulators that can achieve good high frequency PSR performance. In this thesis, two PSR improvement methods are presented. The first method proposes a novel power supply noise-cancelling scheme to improve the PSR of an external-capacitor LDO. The proposed power supply noise-cancelling scheme is designed using adaptive power consumption, thereby not degrading the power efficiency of the LDO. The second method proposes a feed forward ripple cancellation technique to improve the PSR of capacitor-less LDO; also a dynamically powered transient improvement scheme has been proposed. The feed forward ripple cancellation is designed by reusing the load transient improvement block, thus achieving the improvement in PSR with no additional power consumption. Both the projects have been designed in TSMC 0.18 μm technology. The first method achieves a PSR of 66 dB up to 1 MHz where as the second method achieves a 55 dB PSR up to 1 MHz.

Low Dropout Regulators (LDOs) are extensively used in portable applications like mobile phones, PDAs and notebooks. These portable applications demand high power efficiency and low output voltage ripple. In addition to these, the radio circuits in these applications demand high power supply rejection (PSR). The output voltage of a conventional DC/DC converter (generally switched mode) has considerable ripple which feeds as input to these LDOs. And the challenge is to suppress these ripples for wide range of frequencies (for radio units) to provide clean supply. Enhanced buffer based compensation is proposed for the fully on-chip CMOS LDO which stabilizes the loop for different load conditions as well as improve the power supply rejection (PSR) until frequencies closer to open loop‟s unity-gain frequency. The stability and PSR are totally valid even for load capacitor varying from 0 to 100 pF. The proposed capacitor-less LDO is fabricated in On-Semi 0.5 μm fully CMOS process. Experimental results confirm a PSR of -30 dB till 420 KHz for the maximum load current of 50mA. The load transients of the chip shows transient glitches less than 90 mV independent of output capacitance.

The transient analysis of large-scale systems is often difficult even when the systems belong to the simplest M/M/n type of queues. To address analytical difficulties, previous studies have been conducted under various asymptotic regimes by suitably accelerating parameters, thereby establishing some useful mathematical frameworks and giving insights into important characteristics and intuitions. However, some studies show significant limitations when used to approximate real service systems: (i) they are more relevant to steady-state analysis; (ii) they emphasize proofs of convergence results rather than numerical methods to obtain system performance; and (iii) they provide only one set of limit processes regardless of actual system size. Attempting to overcome the drawbacks of previous studies, this dissertation studies the transient analysis of large-scale service systems with time-dependent parameters. The research goal is to develop a methodology that provides accurate approximations based on a technique called uniform acceleration, utilizing the theory of strong approximations. We first investigate and discuss the possible inaccuracy of limit processes obtained from employing the technique. As a solution, we propose adjusted fluid and diffusion limits that are specifically designed to approximate large, finite-sized systems. We find that the adjusted limits significantly improve the quality of approximations and hold asymptotic exactness as well. Several numerical results provide evidence of the effectiveness of the adjusted limits. We study both a call center which is a canonical example of large-scale service systems and an emerging peer-based Internet multimedia service network known as P2P. Based on our findings, we introduce a possible extension to systems which show non-Markovian behavior that is unaddressed by the uniform acceleration technique. We incorporate the denseness of phase-type distributions into the derivation of limit processes. The proposed method offers great potential to accurately approximate performance measures of non-Markovian systems with less computational burden.

Azo-Dye Doped Liquid Crystal (DDLC) is a developed material which can be used to fabricate optical shutter, displays, etc. In this thesis, we presents of the transient grating on a planar aligned DDLC. The effect of various polarizations of writing and probing beams, and of temperature on the transient grating are examined. Then, we propose a model to explain the result. Through this study, we understand the factors that determine the light-induced aligning Dye effect on nematic liquid crystals.

The energy wave scattering method (EWS method) makes use of transmission lines and junctions to model the systems, and switches physical quantities to be energy wave variables then simulates the dynamic response of the systems, finally switches the analyzed results from energy wave variables back to physical quantities. Although using EWS method to simulate the dynamic response of structures is still on the initial stage, figuring out the time domain problems as example as transient analysis is suitable for use. Transient analysis is an important segment of dynamic analysis, it needs more extensive mathematics and newer method of calculation. Probably the EWS method is a workable and typical way. The study tries to use the EWS method to simulate the dynamic response of mutildegree of freedom systems, the response are due to different factors such as initial condition factors, damping factors and external force factors else. Let the simulated results display as displacement-time figures and displacement tables, and compared the results from lumped method or the finite element software-ANSYS with system characteristics by the figures and time domain displacements by the tables. On the whole, the simulated results almost matched with the analytical lumped methods. From the results of the study could confirm the feasibility that using the EWS method to simulate the dynamic response of mutildegree of freedom systems, and further tested and verified the applications of the EWS method on the dynamic analysis.

The thesis includes two aspects. The first part includes designs and optical study of electro-absorption modulator structures. Three structures are designed near 1.5

Chemical vapor deposition is an important thin film process for the fabrication of TFT-LCD(Thin-Film-Transistor Liquid Crystal Display), the heat transfer coefficient on the substrate is the important influence parameter in the manufacturing process. For this reason, the main object of this thesis is to set up a temperature measurement system of transient thermochromatic liquid crystals. Furthermore, an experimental is carried out in the present study to investigate the characteristics of heat transfer resulting from a low speed air jet impinging onto a rectangular substrate confined in a vertical rectangular chamber. Finally, empirical equations are proposed to correlate the effect of Reynolds number¡BSeparation distances and Ratio of outlet.

The main advantage of wavelet transform relative to its Fourier analysis counterpart is its suitability to deal with transient signals. Furthermore, wavelet packet transform has very good frequency analytic ability with the result that it is developing in very fast speed and widespread researched and used in industry and academia. We study the characteristics of fiber optic sensors by applying wavelet transform. Hence, in this paper, the traditional Fourier analysis is taken as a basis, and the wavelet packet analysis is taken as a comparison. The major objects include: (1) calibration of hydrophones; (2) vibration measurement. In calibration of hydrophones, the experimental results show a 2.72 dB re V/£gPa inaccuracies and a 5.3 dB re V/£gPa standard deviation by Fourier analysis, but 0.5 dB inaccuracies and 1.6 dB re V/£gPa standard deviation by wavelet packet analysis. It shows that the wavelet packet analysis has better analytic ability than that of traditional Fourier analysis. In vibration measurement, we utilize FBG interferometers to measure stable vibration. The experimental results denote that wavelet packet analysis has excellent frequency analytic ability as Fourier analysis. Besides, in obtaining transient characteristic signals induced by falling stones, the results appear that wavelet packet analysis has better resolution and identification capability relative to Fourier analysis.