Applied Mechanics and Materials Vols. 55-57

Abstract: High silicon electrical steel prepared by EB-PVD was subjected to high temperature rapid thermal annealing and subsequent pack rolling. The phase composition and Fe configurations were characterized by X-ray diffraction and Mössbauer spectroscopy. The results show that the as-deposited, as-annealed and as-rolled samples mainly consist of DO₃ ordering phase and the as-deposited electrical steel is composed of six kinds of Fe sites corresponding to 333.8KOe, 319KOe, 302 KOe, 284 KOe, 249 KOe, 196 KOe, respectively, while the Fe site corresponding to 196 KOe hasn’t been found in the other two samples. Moreover, the other two samples show a larger Fe site occupancy corresponding to 284 KOe.

Abstract: Assignment problem is a combinatorial optimization problem.In this paper,a improved ant colony algorithm is proposed to solve the assignment problem.According to the rule of state-shift and strategty of updating pheromone, parameters of the ant colony Algorithm are optimized and changed,the best solution can be found rapidly,the simulative results show that the improvement strategies can well improve convergence speed and quality.

Abstract: Materialized view is an effective method for improving the efficiency of queries in data warehouse system, and the problem of materialized view selection is one of the most important decisions. In this paper, an algorithm was proposed to select a set of materialized views under maintenance cost constraints for the purpose of minimizing the total query processing cost; the algorithm adopts the dynamic penalty function to solve the resource constraints view selection. The experimental study shows that the algorithm has better solutions and high efficiency.

Abstract: The convolutive blind source separation (BSS) problem has been received much more attentions in recent years. This paper investigates a convolutive BSS algorithm via employing the time-delayed second-order statistics information and exact diagonalization without any a priori knowledge on the mixtures. This decorrelated second-order statistics and its multi-sample delayed copies, which form two positive-definite symmetry matrices, are obtained from whitened mixtures. By using a set of transforms such as Cholesky decomposition and singular value decomposition (SVD) to these two matrices, a unitary matrix is obtained and utilized to diagonalize them exactly. It attributes the estimates of source signals to this matrix. The similarity between the estimated and original signals is quantified by calculating their correlation coefficients (CC). For the mixtures of speech and noise, ItakuraSaito distance (ISD) is applied to measure the intelligibility of estimated speech signals. Better performance of the investigated algorithm is demonstrated in experimental results compared with the previous algorithm.

Abstract: The kinetics of the corrosion procession of Ni-Cr-Mo-Cu alloys designed by the formula APF=4Cr/ (2Mo+Cu) in NaOH solution have been investigated at the concentration range from 0.0025mol/cm³ to 0.015mol/cm³ and 20°C. It were developed that the kinetic parameters depend on the APF. It is discussed that the dependence of the corrosion resistance to NaOH solution on the APF.

Abstract: The corrosion resistance of Ni-Cr-Mo-Cu alloys designed by formula APF=4Cr/(2Mo+Cu) to aqueous depend on the APF is investigated. The cathodic current of corrosion reactions was expressed as the quantum electrochemical equation. It is discussed that the APF controls the corrosion resistance to aqueous.

Abstract: DC motors are important industrial products. Directly starting a DC motor will harm the motor and the dragged equipment. This article has designed a DC motor control equipment of soft starting, stopping and many protections functions resting on the DC motor control principle and PWM technology. The advantages of this equipment are starting the DC motor continuously and smoothly, low impact torque and impact current, easily controlled, good repeatability, and small volume.

Abstract: In order to improve the interface compatibility of wood fiber and the polylactic acid (PLA), the silane coupling agent to modify the wood fiber was chosen. The Modified Effect of silane coupling agent on the wood fiber is judged inrectly by feat of the modification of viscosity characteristic of the mixed system of wood fiber and the liquid paraffin. The dosage of the silane coupling agent influenced the modification effect the most is shown in the research, the modification temperature, stirring speed and the modification time are followed.

Abstract: Prepare composite materials with recycled fibers from waste newspaper and PLA by inject-molding process, and study on recycled fiber of the modified-property treatment of silane coupling agent and alkali deinking treatment influence properties of composite materials. It is found out that, recycled fibers under the modified-property treatment of silane coupling agent and under alkali deinking treatment can effectively improve compatibility between recycled fibers and PLA, and improve mechanical properties and water absorbency of composite materials.

Abstract: The main objective of this research is to study the reinforcement role of the adhesively bonded patches in the structure. In order to evaluate the mechanical behaviour of the structure reinforced with external patches, a shear lag model was adopted to investigate the load transfer from the host structure to the adhesively bonded patches. Closed-form solutions of the shear stress in the adhesive and longitudinal forces in the reinforcement patch and host structure were obtained. The theoretical predictions were validated with the numerical analysis using the finite element method. The effect of the adhesive on the load transfer was presented through a parametric study.