Advanced Materials Research Vol. 462

Abstract: A systematic approach is introduced to infer surface structure of visible object surfaces using grid coding in this paper. The visualized object, which has surface of a terrain-like shape, is assumed to derive from data field of gird points defined by orthogonal division and data acquisition. Parametric surface is used to spatially represent the data for analysis. Central difference technology is presented to tessellate the curved surface and generate view-dependent multi-resolution models, which has excellent performance in real-time applications. Besides, an algorithm for data pre-processing is presented. The approach presented here also adapts to data acquired in realistic scene, which can be a virtual reality application. Comparing to previous methods, the method presented in this paper provides good flexibility in various applications. It works well in real-time graphic application while has good visual quality.

Abstract: A particle filtering equalization algorithm with unknown noise variance is presented based on the optical particle sampling using the optical importance function. The optical importance function with unknown noise variance is deduced by analytically integrating out the noise variance as a nuisance parameter. And the posterior distribution of noise variance is derived recursively based on its prior distribution. Moreover, the optical particle sampling using the optical importance function is introduced to alleviate the degeneracy phenomenon so that a re-sampling step is avoided in the method. Numerical simulations show that the degeneracy problem of the proposed algorithm is alleviated greatly, and the proposed algorithm attains an approximate performance to the one with known noise variance.

Abstract: In thin-film thickness wideband monitoring system,in order to eliminate error accumulation effect of layers which have been deposited on layer which will be deposited, the thin-film optical constants of layers deposited must be achieved.Utilizing transmittance spectral curve which has been measured, Simulated Annealing Algorithm is applied on inversion of optical constants n,k,d.For the purpose of increasing optimization speed and algorithm efficiency,the algorithm is improved, exponent dropping temperature rate varies with acceptance probability P ;The finding range of new value is controlled adaptively according to acceptance rate when the dropping temperature is t,then the algorithm is applied on the example that is membrane ZnS is deposited on the substrate of quartz glass , n,k,d are obtained in a shorter time by optimization and their values are satisfying.

Abstract: The changes in flow channel area and convergence-expanding nozzle help to flow rate of natural gas to the sound speed, also increase diameter to accelerate flow velocity and finally reach transonic flow condition. At this point, the temperature drop makes saturated water in natural gas condenses into droplets, generates swirl around the delta-wing, realize gas-water separation. This paper concentrates on Flent6.1 software process gas flow around a delta wing simulation, explains expansion angle and attack angle of delta-wing, determines a reasonable delta-wing attack angle is 10°, pipeline expansion angle is 0.29°, and obtains velocity vector, mach number, total pressure, static temperature and other flow field details of the attack angle and expansion angle, which lay foundation for production and application of the technology.

Abstract: This document modified the basic genetic algorithm three important operator—selection operator, mutation operator, crossover operator drawing from competition, selection, and fitness niche adjustment idea. Take the unbalanced magnetron sputtering deposition of DLC films on Si substrate as a research sample. When fitting wavelength range is 300 ~ 1500nm, select a point every 1nm, the fitting lasting time is no more than 6s. Fitting results contrast to ellipsometer’s fitting results; the error is less than 2%. Experiments show that: the adaptive modified is effective in preventing the "premature" phenomenon, searched the global optimal, reduces the requirements on the operator to set the initial value on the fitted model and is effectiveness to fit thin film optical constants.

Abstract: In this study, optical fiber probes were fabricated by combination of electric arc discharge and chemical etching techniques. Size of tips diameters fabricated using different etching solutions were observed. When the optical fibers were pulled and heated by the electric arc discharge using a fusion splicer, fiber tips with few microns in diameter were obtained. To minimize the tips diameter, the pulled fiber probes were etched vertically for 10 minutes using two different etching solutions namely 49% HF and HF buffer solution (49% HF and 40% NH4F) with ratio of 2:1. A thick overlayer was added on top of the HF solution to prevent dangerous vapors escape to the environment. When the tapered part of the pulled fiber (FP1) was dipped into 49% HF solution, the diameter of tip was slightly decreased from 4.41μm to 1.31μm with etching rate of 5.17x10^-3 μms-1. When the pulled fiber (FP2) was etched into HF buffer solution, the etching rate was increased up to 52.35% with the etching rate of 10.85x10^-3μms-1. The tip diameter was reduced from 7.01μm to 468.9 nm in diameter. Combination of “heat and pull” technique with chemical etching by using HF buffer solution produced fiber probe with small tip diameter.

Abstract: By doing research on the optical characteristics of TFEL panel, a driver circuit controlled by Field-Programmable Gate Array(FPGA) is designed. This design adopts an unsymmetrical way to lighten the panel which is different from the custom symmetrical hybrids. The availability of this unsymmetrical structure improves the stability when the system is on the high-voltage condition, prolongs the service life of the driver circuit, and significantly reduces the costs of a TFEL display system.

Abstract: It analyzes in detail the influence factor of voltage of proton exchange membrane fuel cell (PEMFC) when load changes sudden by the lumped modeling developed. The partial pressure of hydrogen and oxygen can be expressed using the ideal gas law equation, and ohmic loss, activation loss and concentration losses are accounted, it is assumed that both operating factor of hydrogen and mixture ratio of hydrogen and oxygen are constant. Based on the above, the dynamic lumped model of PEMFC is proposed. The correctness of model is verified by comparing the experiment data with simulation result of model. The research about lumped model has important significance to the research of the distributed generation network in various performances.

Abstract: Based on finite element Method a dynamic mathematical model is established, and the simulation of stress distribution around the defects of single crystal nickel-based superalloysis also established with ANSYS. Results show that the creep lifetimes and plasticity of the single crystal nickel based superalloys are obviously decreased by microstructure defects. During high temperature creep, the stress isoline near the holes region displays the feature of the acetabuliform distribution, and possesses the bigger stress value at 45 angle direction relative to the applied stress axis. That results in the  phase transformed into the rafted structure at 45 angle direction relative to the applied stress axis, and the circular holes defects are elongated into the ellipse in shape along the direction parallel to the applied stress axis. During creep, a smaller value of the stress distribution displays in the up and down regions of the circular holes, and the maximum value of the stress distribution exhibits the apices region in the sides of the hole.