Advanced Materials Research Vols. 472-475

Abstract: Based on the coupled mode theory and the FORTRAN software, study are carried out for the frequency response in a coaxial Bragg reflector with gradual change ripples. Results show that the characteristics of frequency response in the positive gradual change or the negative gradual change ripples coaxial Bragg reflector are the agreement, and the bandwidth of the coaxial Bragg reflector with gradual change ripples can be expanded as the gradual angle augmenting when the incident mode is Single-mode and lower frequency; When the incident mode is Coupled-mode and higher frequency, the bandwidth of the operating mode and the spurious mode also all can be expanded as the gradual angle augmenting, but the negative gradual change ripples can get higher frequency than the positive gradual change when the gradual angles are same; and the residual side-lobes of the frequency response also can be effectively suppressed. These characteristics of a gradual change ripples coaxial Bragg reflector are favorable to improvement of the performance as a reflector or a filter in its applications.

Abstract: The extended finite element method (XFEM) provides an effective tool for analyzing crack problems.The control equations and the weak form can be established through balance equations ,boundary condition, geometry equations,etc.After the establishment of stiffness matrix,the crack problems can be solved by XFEM conveniently.

Abstract: Reservoir capacity is a very important parameter for reservoir. This paper discusses the use of contour lines to establish digital elevation model (DEM) of reservoir, and to calculate reservoir capacity to improve the accuracy of the capacity calculation through the method that uses digital elevation model.

Abstract: Distributed geometric features such as adjacent auxiliary holes with certain tolerance requirements are common geometry to be machined in many complex structural components. The machining sequencing decision of such features has high impact on the machining efficiency of the part. This paper conducted an algorithm to generate optimal machining sequence of the distributed holes in a machined part by using simulated annealing. The procedures of the algorithm were introduced. Distributed holes machining of an example part has been considered in the paper to exam the algorithm to find an optimal machining sequence of the holes in the row blank operation. The impacts of algorithm parameters on the results such as the starting annealing temperature, temperature coefficient and iterations are studied. Comparisons of the machining route before and after optimization were performed. According to the optimized sequencing, total distance and transfer time of cutting tools were greatly shortened. Therefore, the machining sequencing optimization of distributed holes can raise the machining efficiency in practice and has great significance.

Abstract: The paper presents a fitness formula which is adopted to calculate the steel ball temperature uniform distribution time in the annealing process, analyses the steel ball temperature distribution in the process of heating. After the heat conduction equation of the steel ball is deduced, the spherical bessel function is adopted to solve it. The temperature distribution series solution is obtained. Using this formula, the steel ball temperature uniform distribution time of the different radius is calculated in the process of annealing. The result shows that the steel ball temperature uniform distribution time is the quadratic function of the steel ball radius. The time and radius data is adopted to deduce a second-order fitness polynomial. The steel ball temperature distribution is obtained in the different position. The steel ball temperature uniform distribution time is calculated by the fitness formula and the temperature distribution series one. The error between them is only 0.03%. The fitness formula can be used to calculate the steel ball temperature uniform distribution time. The change of the steel ball surface temperature is more severe than the internal. It often results in the crack of the steel ball in the annealing process.

Abstract: Constant-temperature drying tests for cotton straw under different conditions were performed with an integrated thermal analyzer, and the influence of different drying conditions on the drying process was analyzed. The process was divided into preheating stage, constant-rate drying stage, and decelerating drying stage. Regression analysis was conducted for drying curves at the latter two stages, and then the drying time at the critical point was determined. Regression equations of drying rate at these stages were produced. Research results showed that the decelerating drying stage of cotton straw included two decelerating intervals, and the best ending point of the drying of the cotton straw that had an initial moisture content of 56.1% and a drying temperature of 100°Cwas 600s, thus providing experimental data and reference for research on drying technology of straws.

Abstract: For developing carbon based adsorbents for hydrogen storage, Staram PCTPro E&E was employed and activated carbon SAC-02 having specific surface area about 2074m2/g was selected to measure isotherms of hydrogen adsorption respectively from temperature range 77.15K-110.15K and 253.15K-293.15K. Isosteres of hydrogen adsorption on the activated carbon was then plotted to determine the isosteric heat of hydrogen adsorption, and temperature dependent of Henry law constants were further applied to set the limit isosteric heat of adsorption at zero surface coverage. Results show that the isosteric heat of adsorption is about 3.6-5.4kJ/mol with a mean value 4.38kJ/mol at zero surface coverage. Results also reveal that adsorption isosteres of adsorption data at different temperature regions bring about a different isosteric heat of adsorption due to the variation in contributions from thermal motion of adsorbate molecules. Conclusions are drawn that adsorption isosteres on the adsorption data in correspondence with the lowest and highest temperatures of the hydrogen storage system should be carried out to determine the isosteric heat of adsorption for effectively managing the thermal effect.

Abstract: This paper mainly focuses on the work principle of pulverized coal direct-fired stove aiming to obtain the process and characteristics of thermal gas furnace. The pulverized coal created in the drying process can be captured directly in the internal system, which can deal with such problems as storage and transport, especially the environment protection problem such as dusty flying. Pulverized coal stove can be promoted in the lignite quality-improving project based on the data collected from the production field.

Abstract: In view of the HVAC and fan-coil system utilizing geothermal water whose temperature range is from 60°C to 85°C,the objective function of system has been established. The temperature parameters of all levels and the optimum recharge temperature of geothermal water are obtained by using MATLAB software. At the end of the paper, supply-water temperature of load side influencing on the price and coefficient of performance of high temperature heat pump have been analyzed in theory.

Abstract: The hidden unit number of RBF neural networks directly influences the performances of the whole net. A new strategy to prune the hidden units based on the singular value decomposition (SVD) of matrixes is proposed in the paper. At the basis of a structure involving enough more hidden units, the paper analyzes the outputs corresponding to some training samples with the SVD method and finds out the internal relations of them, then removes redundant ones according to the contribution rate of every hidden unit to the whole network, simplifies the structure of RBF neural network at last. The optimized network has strong generalization ability with simpler structure. At the end of this paper the new strategy is successfully used in the main steam system modeling of power plant and confirmed by simulation experiments.