Advanced Materials Research Vols. 418-420

Abstract: The RF applications like voltage controlled oscillators, tunable filters, resonators etc., requires variable capacitors in their design. This paper presents a novel micro variable capacitor consisting of fixed plate and moveable plate which is suspended by ‘S’ type springs. Micro variable capacitor can be electrostatically actuated via applied voltage to change the capacitance between the plates. The capacitance changes from15 pF to 22.5pF while applied voltage ranges from 0 to pull-in voltage. And micro variable capacitor based on glass Substrate was fabricated by simple micro electromechanical systems (MEMS) technology.

Abstract: A mathematical model of fractal interpolation surface is introuduced in this paper. A calculation to fractal dimension of the messy point data is proposed and used to get appropriate vertical scale factor to construct precise blank residue model. Fractal dimensions of different fractal interpolation surfaces with different vertical scale factor are different. The relationship between vertical scale factor and fractal dimension is obtained through calculating fractal dimensions of tested surfaces which are created by fractal interpolation with different vertical scale factor.

Abstract: Malaysia is one of the world pineapple producers besides Thailand, Philippine, Indonesia, Brazil and South Africa. The government encourage farmers to have more production to meet increasing demand for export. Most of the pineapple production activities is still in manual process and rely on labor workers. In this paper, we proposed a system that can be used in production house to automatically detect the maturity index of pineapple. We implement image processing method to determine the maturity of a pineapple based on yellowish skin color. Binary ellipse mask has been used for extracting region of interest (ROI) as well as morphology normalized RGB to filter out the background and unwanted pixel image. Finally, linear method using threshold values has been selected to classify the maturity index. 910 pineapple images has been used at the development and testing stage and we obtained promising result with 94.29% good classification rate.

Abstract: The finite element models of extruded sealing ring which had the same installation specifications but different structure sizes of sections were established, and the results from finite element analyses of the axial stiffness of these models were compared, then, an excellent characteristic of the shape of sealing ring on axial stiffness was found.

Abstract: The 3D model of gear with asymmetric profile and double pressure angles is built by the autodesk inventor software. It is imported and analyzed by the ANSYS software. Then each order natural frequencies and mode shapes are obtained. So resonance and harmful mode shapes can be avoided, and dynamic performances of gear with asymmetric profile and double pressure angles is improved. This paper has a certain reference value for the dynamic design of other types of gears.

Abstract: Nd₃Fe₅O₁₂ crystallites were prepared by a hydrothermal method using Nd(NO₃)•6H₂O Fe(NO₃)•9H₂O and Bi(NO₃)₃•5H₂O as raw materials. XRD, SEM and PPMS were used to analyzed crystal phase, morphology and magnetism of the crystallites, respectively. XRD result showed that the crystallites present cubic garnet phase without impure phase; SEM result showed that the crystallites are composed of rhombic dodecahedron grains with a very even with size of 10 μm. Moreover, magnetism of the crystallites was studied. The crystallites present intense antiferromagnitsm.

Abstract: To adjust temperature as the requirement of process curve, an intelligent control system of temperature was designed. In the system, the fuzzy rule was used to adjust parameters of PID controller. Adjusted PID controller was used to control the change of temperature. The system can avoid the disadvantages of common PID, such as, long setting time, wide overshoot, and acquire better control characteristic. It were expatiated that principle and method of control. The hardware structure and the software flow chart were also introduced.

Abstract: Ethylene oxide (EO) is an important organic chemical material, and Silver catalyst is an important petrochemical catalyst and is regarded as the core of EO/EG production process. The catalyst's performance is the major factor that directly determines the economic efficiency of commercial production of ethylene oxide. In this paper, we will introduce the development and application of YS silver catalysts developed by Beijing Research Institute of Chemical Industry, SINOPEC.

Abstract: The effect of different austempering holding times on the hardness and impact toughness of 0.254% niobium alloyed austempered ductile iron was investigated in this study. Molten ductile iron was prepared in an induction furnace with capacity of 60kg. Samples with dimension of 300m x Ø25mm in form of Y block double cylinder was constituted and solidified samples were then machined in accordance to ASTM E23 for impact test specimens. Samples were ground and polished before Rockwell hardness test was conducted. Austempering heat treatment process with austenitizing temperature of 900°C for 1 hour and austempering temperature of 350°C for 1 hour, 2 hours and 3 hour holding times were then carried out. The results from this research indicated that austempering the sample for 1 hour resulted in significant improvement of the impact toughness values but increasing the austempering holding time deficiently reduced the values. On the contrary, the hardness of niobium alloyed austempered ductile iron continues to increase with respect to longer austempering holding times.

Abstract: A novel phase-shifted Soft-switching converter is presented in this thesis，which is based on the Tou structural, groundwork of summarization of the development of lower Electronics in recent years and lucubration in theoretical basis of modern high frequency soft switching power convert technique and analysis of operation principle, characteristic of the circuit and inherent drawbacks of traditional phase-shifted Soft-switching converter. Explicit description of main circuit topology, operation principle, characteristic of the circuit of the novel phase-shifted Soft-switching converter as well as the simulation analysis with the PSPICE software is proposed. The main works that I did: The design involves calculation of transformer, inductor and capacitance in main circuit, parameter selection of each element and realization of control circuit. Electric circuit Tou structural is verified by emulation experiment. The electric circuit reduces availably switch exhaust of traditional soft switch transformation electric circuit. The experiment proved to the possibility of the reformed prefect. The experiment has important reference value to improved soft switch transformation.