Cylindrical dielectric waveguides such as the optical fiber and photonic crystal fiber are very important passive devices in optical communication systems. There are many kinds of commercial software and methods of simulation at present. In this thesis, we proposed the following four methods to analyze arbitrarily profiled cylindrical dielectric waveguides: The first two methods are modified from published work while the last two methods are entirely developed by ourselves. 1. Cylindrical ABCD matrix method: We take the four continuous electromagnetic field components as main variables and derive the exact four-by-four matrix (with Bessel functions) to relate the four field vector within each homogeneous layer. The electromagnetic field components of the inner and outer layer can propagate toward one of the selected interface of our choice by using the method of ABCD matrix. We can then solve for the £]-value of the waveguide mode with this nonlinear inhomogeneous matrix equation. 2. Runge-Kutta method: Runge-Kutta method is mostly used to solve the initial value problems of the differential equations. In this thesis, we introduce the Runge-Kutta method to solve the first-order four-by-four nonlinear differential equation of the electromagnetic field components and find the £]-value of the cylindrical dielectric waveguides in a similar way depicted in method one. 3. Coupled Ez and Hz method: It uses the axial electromagnetic filed components to solve cylindrical dielectric waveguides. The formulation is similar to cylindrical ABCD matrix method, but it requires less variables then cylindrical ABCD matrix method. The numerical solution obtained from this method is most stable, but it is more complicated to derive harder to write the program. 4. Simple basis expansion method: The simple trigonometric functions (sine or cosine) are chosen as the bases of the horizontal coupled magnetic field equation derived from the second-order differential equation of the transverse magnetic field components. We do not select the horizontal coupling electric field because the normal component of the electric field is discontinuous on the interface. But the normal and tangential components of the magnetic field are continuous across the interfaces. The modal solution problem is converted to a linear matrix eigenvalue-eigenvector equation which is solved by the standard linear algebra routines. We will compare these four numerical methods with one another. The characteristics and advantage as well as the disadvantage of each method will be studied and compared in detail.

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Liquid crystal display is the most valuable and universal produce of the electric monitor presently and it will into the stage of stable. In the future, the reliability is more important and also will be gradually the key point of index. Most of studies about the reliability of the back light module that concentrate on the thermal effect, there are seldom researches corresponding to the humidity and time effect. Therefore, we emphasize thermal, humidity and time factor for optical performance influence of the back light module in this thesis. We also used the experimental design of Taguchi method to determine the most important factor and development the basic for the reliability of the back light module. According to the result, the changing of the temperature influence the optical performance is the most.

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The research is of aluminide and silicide coating layer on 310 stainless steel by the pack cementation method. We use TEM,SEM,OM,X-ray instruements to analysis the coating layer.We find the aluminide layer good to protect substrate. The aluminide layer to resist oxidiation is better than silicide.We believe the method of the pack cementation will be developed very well in the future

A turbomolecular pump (TMP) with good performance must have higher compress ratio and higher pumping speed. At the same time, the performance of turbomolecular pump depends on blade geometries and the rotational speed. When design the blade of Turbomolecular Pump, the blade geometries including, the blade angle, the blade spacing, the blade chord, the spacing-chord ratio, the tip diameter, the root diameter, and the number of blades and as well as the rotational speed of the rotor must be considered. In this paper the simulation for gas molecular behavior is obtained by the Monte Carlo method. Therefore, a Maxwellian distribution of particles at the inlet and outlet of the flow region and diffuse reflection for the particles that collide with the walls are assumed. Models of this type have been applied to the two-dimensional case. The most important result is to compare the performance between turbomolecular pumps with curve style and plane style of blades. Furthermore, that direct multi-stage simulation (DMS) by Monte Carlo method is used in this paper. The compression ratio multiplication (CRM) method is the improved due to the considering the change of velocity distribution of molecular at the adjacent stages. From results of the simulation, the effect upon the geometric parameters of the blades and the arrangement in the multi-stage are concluded, that are very useful in designing the turbomolecular.

This paper uses a finite element code¡©DEFORM 3D¡ªto simulate the plastic deformation behavior in extrusion processes of heat sink for CPU. The relationships between the loading, strain, velocity distribution, and formability of the extruded product as well as the extrusion conditions are discussed. Furthermore, this research will propose a criterion for the die design of heat sink and to prove the validity of this proposed criterion by the experiments.

Inverse problems arise in many branches of natural science, medicine and engineering involving the recovery of a whole function given only a finite number of noisy measurements on functionals. Such problems are usually ill-posed, which causes severe difficulties for standard least-squares or maximum likelihood estimation techniques. These problems can be solved by a method of regularization. In this dissertation, we study various problems in the method of regularization. We develop asymptotic properties of the optimal smoothing parameters concerning levels of smoothing for estimating the mean function and an associated inverse function based on Fourier analysis. We present numerical algorithms for an approximated method of regularization estimator computation with linear inequality constraints. New data-driven smoothing parameter selection criteria are proposed in this setting. In addition, we derive a Bayesian credible interval for the approximated method of regularization estimators.

Over the past three decades, coalbed methane (CBM) has moved from a mining hazard and novel unconventional resource to an important fossil fuel that accounts for approximately 10% of the U.S. natural gas production and reserves. The expansion of this industry required development of different drilling, completion and stimulation practices for CBM in specific North American basins, owing to the complex combinations of geologic settings and reservoir parameters encountered. These challenges led to many technology advances and to development of CBM drilling, completion and stimulation technology for specific geologic settings. The objectives of this study were to (1) determine which geologic parameters affect CBM drilling, completion and stimulation decisions, (2) identify to the engineering best practices for specific geologic settings, and (3) present these findings in decision charts or advisory systems that could be applied by industry professionals. To determine best drilling, completion and stimulation practices for CBM reservoirs, I reviewed literature and solicited opinions of industry experts through responses to a questionnaire. I identified thirteen geologic parameters (and their ranges of values) that are assessed when selecting CBM drilling, completion and stimulating applications. These are coal thickness, number of seams, areal extent, dip, depth, rank, gas content, formation pressure, permeability, water saturation, and compressive strength, as well as the vertical distribution of coal beds and distance from coal reservoirs to fracture barriers or aquifers. Next, I identified the optimum CBM drilling, completion and stimulating practices for specific combinations of these geologic parameters. The engineering best practices identified in this project may be applied to new or existing fields, to optimize gas reserves and project economics. I identified the best engineering practices for the different CBM basins in N.A and combined these results in the form of two decision charts that engineers may use to select best drilling and completion practices, as well as the optimal stimulation methods and fluids for specific geologic settings. The decision charts are presented in a Visual Basic Application software program to facilitate their use by engineers.