In this thesis, the relation between the fractal structure and the performance of the antennna is discussed. From the simulation and theoretical analysis , we can conclude that the 10dB impedance bandwidth of the monopole decreases when the iteration level of the fractal structure increases . Then we use the fractal structure to design the LTCC antenna. We design and manufacture an LTCC antenna for WLAN IEEE 802.11a. The simulation and measured results are analyzed and discussed. Finally, we provide a new method which can reduce the cross polariztion level. And this method is used to reduce the cross polarization of the monopole using the second iteration level of the Minkowski curve. It is shown that the method does work from the measurement. This method can reduce the cross polarization of the fractal antenna and hence find more application in communication systems.

Three subjects on the organic light-emitting diodes (OLEDs) have been studied. First, We inserted a NPB¡GAlq3 mixed layer between these two NPB and Alq3 layers to decrease the holes mobility and improve the combined efficiency between the holes and electrons. After inserting the NPB¡GAlq3 layer, the current density of the device( ITO/ MTDATA¡]5 nm¡^/ NPB¡]60-Y¡^nm¡^/NPB¡GAlq3 (Z wt%)(Y nm) / Alq3¡]60 nm¡^/ LiF(0.7 nm)/ Al(180 nm)) is decreased obviously. This result suggests that NPB¡GAlq3 layer could delay the holes mobility. The optimum concentration in our device is 30 wt% while the total thickness is 30nm. Then we combined NPB and Rubrene to obtaine white emission and fabricate a white organic light emitting diode (WOLED). The structure of WOLEDs is ITO/ MTDATA/ NPB/ NPB:Rubrene/ TPBI/ LiF/ Al. By change the concentration of NPB:Rubrene layer, the WOLED can emit white light. We can get the maximum luminance efficiency of 9.0 cd/A at 20.8mA/cm2 with 1 wt%. And the device emit greenish-white. In order to get higher efficiency and pure light WOLED, we use the grading structure to prepare OLED. The structures are device A: ITO/ MTDATA(5nm)/ NPB(10nm)/ NPB:Rubrene1%(25nm)/ NPB:Rubrene 0.5%(25nm)/ TPBI(60nm)/ LiF(0.7nm)/Al (180nm); device B: ITO/ MTDATA(5nm)/NPB(10nm)/NPB:Rubrene2%(17nm)/ NPB:Rubrene1% (17nm)/NPB:Rubrene0.5%(17nm)/TPBI(60nm)/ LiF(0.7nm)/ Al (180nm) We get the maximum luminance of 17270 cd/m2 and 24280 cd/m2 , respectively and the optimum efficiency of 16.1 cd/A and 18.5 cd/A, respectively. The CIE coordinate of the device is x=0.35, y=0.36, which is identical to white light.

Various proteins with specific properties and functions exist in organisms, they perform all important biochemical activities. The biochemical functions of proteins are determined by their structures. One of the most important issues in the life science is to predict the three-dimensional structures with protein sequences, and then to deduce their biochemical functions. To predict protein structure precisely will accelerate biochemical research. However, it is a challenge task to obtain the real structure of a protein. The objective of this study is to develop a protein structure prediction methodology based on a structure-known protein (such as the proteins in the PDB database), where the two protein sequences are extremely similar. Some folding algorithms, such as U-fold and S-fold, have been developed to predict protein structures. However, the folding algorithms work on a grid lattice, which is very different from the real structure of a protein. Here we use the curve fitting technique, such as B-splines, to convert the lattice model and a real structure to the same domain, that is, the curve. We therefore perform curve (structure) alignment on them. The curve alignment can also be used to evaluate the similarity between two structures. By the experimental results, our protein structure prediction method performs well when we get two protein sequences with similarity that is not too high.

Abstract The Projected Shell Model has been applied to the Isotones even (odd -odd) mass nuclei La; odd (odd - even)mass Ce, and odd (odd - even)mass Nd nuclei, to investigate the high-spin superdeformed phenomena. The theoretical calculated transition energy E£^, kinetic moment of inertia J(1) ,and dynamic moment of inertia J(2) are compared with experimental data. High-spin superdeformed nuclei behave like rigidbody ,the physical meaning .show a large gap at N=73¡BZ=58 and Z=60.

Plant luteoviral RNA viruses employ -1 frameshifting for the production of P1 and P1-P2 fusion proteins important for viral replication. Luteoviral pseudoknots are characterized by three adenosines in the 3' side of loop L2 known to be important for maintaining frameshifting efficiency and pseudoknot stability. A proposed P1-P2 mRNA pseudoknot from sugarcane yellow leaf virus (ScYLV) was of interest since it contained two adenosine to cytidine substitutions in L2. Functional analysis shows that the in vitro frameshifting efficiency is greater (~15%) than any other luteoviral pseudoknot. The NMR-derived solution structure of the ScYLV RNA pseudoknot shows that C25 is looped out of the triplex structure and the 3' most L2 cytidine (C27) and A24 form cis Watson-Crick/sugar-edge interactions with C14 and C15 in stem S1, respectively. Thus, the ScYLV pseudoknot maintains a similar triple helical architecture as other luteoviral pseudoknots. Surprisingly, the frameshifting efficiency of the C27A ScYLV pseudoknot is decreased by ~8 fold relative to wild-type ScYLV. The solution structure of the C27A ScYLV RNA exhibits a global fold similar to the wild-type RNA; however, distinct hydrogen bonding interactions at the helical junction are observed. Specifically, C8+ in the C8+ major groove base triple moves ~2.3 relative to the accepting (G12-C28) base pair relative to the WT RNA. New NMR experiments have been developed and/or applied to confirm Watson-Crick base pairs and tertiary structural interactions in the PEMV-1 and ScYLV pseudoknots by direct observation of trans hydrogen bond scalar couplings. In addition, intrabase couplings in cytidine and adenosine have been measured, providing a valuable tool for the assignment of amino and N3/N1 resonances in RNA. Finally, thermodynamic analysis of the pairwise coupling between the major groove and minor groove tertiary structural hydrogen bonds at the helical junction have been investigated by monitoring the thermal unfolding of WT, dC14, C27A, and dC14/C27A RNAs as a function of pH. Favorable pairwise coupling characterized the WT ScYLV and BWYV RNAs, while unfavorable coupling characterized the poorly functional C27A ScYLV RNA. The implications of these structural, functional, and thermodynamic findings on the mechanism of frameshift stimulation is discussed.

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In state-of-the-art software library, such as Standard Template Library (STL) , they support a number of data models, for example, set, map, sequence, etc. Since graph data processing is widely used in combinatorial processing and optimization programs, in this research, we designed software implementation of a condition-based graph structure recognition method. This design consists of four kinds of condition functions specific to graph structures, control functions of structure recognition operation flow, and programming interface to facilitate programs writing various efficient graph structure recognition programs. We implemented a software library of this graph structure recognition method to support program design containing graph data and processing.

<p>Measurements of partial discharges are commonly used to diagnose the insulation system in high voltage components. Traditionally a single xed frequency of the applied voltage is used for such measurements as in the Phase Resolved Partial Discharge Analysis (PRPDA) technique. With the Variable Frequency Phase Resolved Partial Discharge Analysis (VF-PRPDA) technique the frequency of the applied voltage is instead variable. This technique provides more information about the condition of the insulation than the PRPDA technique. To extract the extra information a physical understanding of the frequency dependence of partial discharges is necessary.</p><p>In this thesis partial discharges in cylindrical cavities in polycarbonate are measured using the VF-PRPDA technique in the frequency range 10 mHz { 100 Hz. It is studied how the cavity diameter and height inuence the frequency dependence of partial discharges. Insulated cavities are compared with cavities bounded by an electrode. It is shown that from measurements at variable applied frequency it is possible to distinguish between cavities of di erent dimensions and between insulated and metal bounded cavities.</p><p>A two-dimensional eld model of partial discharges in a cylindrical cavity is developed. The sequence of discharges in the cavity is simulated by use of the eld computation program FEMLABR. Discharges are modeled with a voltage and current dependent streamer conductivity and are simulated dynamically to obtain charge and current consistency. It is shown that the frequency dependence of partial discharges is signi - cantly inuenced by the statistical time lag and by the two dielectric time constants related to charge movements on the cavity surface and in the bulk insulation. Simulation results are used to interpret the frequency dependent partial discharge activity in a cylindrical cavity.</p>

Th. doct.--ciècies humanes i socials--Universitat de Barcelona, 1994. / Le livret d'accompagnement comprend un résumé en catalan et en anglais ainsi que le sommaire de la thèse microfichée.

Diss.--Philosophische Fakultät III--Universität Regensburg, 1999. / Bibliogr. p. 275-283. Index.