Applied Mechanics and Materials Vols. 143-144

Abstract: A new system for measuring bridge deflections based on laser imaging process is introduced. Firstly, principle of this system is analyzed with geometrical optics theory. Secondly, hardwares of measuring system are illuminated in detail, and the key software problems are discussed, including laser spot center location and accurate control of motorized TV zoom lens. The laser spot center location is realized by using image fuzzy edge extraction algorithm and Hough transform algorithm. The accurate control of motorized TV zoom lens' motors is realized by using a control-driving card based on ISA bus. At last, the contrastive experiments are operated on a certain continuous steel bridge with this system and dial test indicator. The experimental results show that this system is equal precision with dial test indicator, and can get over defects of traditional measuring methods. The security and reliability is much higher relatively and the precision can match to the engineering requirement.

Abstract: Time-resolved circularly polarized pump-probe spectroscopy is used to study the carrier density dependence of the electron spin polarization dynamics in AlGaAs/GaAs multi quantum wells at room temperature. Experimental results show that the spin relaxation time increases with the carrier density, which is in conformity with D'yakonov-Perel relaxation mechanism.

Abstract: This paper proposes a frequency domain method to analyze the harmonics components of input current and ripple coefficients of output voltage in 12-pulse diode rectifier system. Based on frequency domain linearity and analysis of commutation, the dc side output voltage and input line current are divided into two segments, and then expressions of the input current and output voltage are obtained. Some simulation results about THD, power factor and ripple coefficient are shown to validate the correctness of the proposed method

Abstract: Activated sludge process is generally applied on biological wastewater treatment. The Activated sludge Model No.1 (ASM1) is a mathematical description of biochemical processes in the reactor for nitrogen and chemical oxygen demand removal. ASM1 model was used to simulate the concentrations of components in leaving water with single-stage completely mixed CSTR (continuously stirred tank reactor) assumed. According to the concentrations of components in entering water of published data, curve simulation results of SNH and SNo show that the nitrogen removal process follows the nitrification-denitrification principle. And the steady-state results of 10 kinds of selected components indicate the simulation of the components concentration of leaving water is relatively accurate,and the nitrogen removal effect is obvious. The simulation system can provide effective technical support for wastewater treatment of actual plant.

Abstract: The traditional method to introduce the design of big tree fractal graphics is to give fixed graphics in black color. In this paper, a new learning environment of triangle fractal graphics based on E-Learning is proposed, development of which is also introduced in detail. In this new learning environment, students can repeat drawing the colorful big tree fractal graphics with single color or random color, which may arouse the students' interests and attract their attentions. By the learning environment, the fractal limitation or fixed point can be seen, and two different kinds of big tree can be got when the IFS code is changed, which will do benefit to students' learning concepts of fractal graphics. By this new learning environment, it is very easy for students to grasp the programming procedure of fractal graphics, and understand the generation procedure and structure of triangle fractal graphics.

Abstract: Community is not only the cell of society, but also the basic component of city. To improve urban public disaster prevention and mitigation system must start from the safety construction of community. In the way of introducing the classification of urban community, summarize and analysis the public disaster prevention and mitigation resources in the community, sum up the relationship between public disaster prevention and mitigation resources and common disasters in community, construct evaluation system of community disaster prevention and mitigation resources. Using Analytic Hierarchy Process (AHP) and expert scoring, establish all evaluation indexes weight coefficient. Ultimately, assessing and grading single hazard prevention resources, on which base put forward an algorithm of overall evaluation of disaster prevention and reduction resources.

Abstract: The resources in cloud computing environment are dynamic and different tasks have varied demands for resources. Traditional way for task scheduling cannot effectively schedule the resources according to different QoS requirements. In order to adapt the dynamic task requirements and allocate the resources reasonably, in this paper, we propose seven specific indexes which can be integrated into three indexes called resource cost, load and completion time. At the same time, we establish the model of BP nerve network to evaluate resources by using VC++6.0 development tool and MATLAB simulation software. Experimentation shows that our model can successfully choose the optimal node and provide basis for resources scheduling

Abstract: The five-octave mill stochastic dynamics model was established, and then constructed the virtual rolling force excitation, converted random excitation into the rolling force deterministic harmonic excitation by taking advantage of pseudo-excitation method, finally the variance and power spectral density dynamic random changes in the roll gap was Obtained . The results show that the emergence degree of rolled-strip oscillation marks is proportional to random rolling force power spectral density, and in over the five-octave frequency, the roll gap’s dynamic variance no longer change.

Abstract: With railways, highways continues to build, expansion of tourism development and urban construction, to some extent destroyed the native geology, geomorphology, resulting in great loss of water and soil, geological disasters have occurred frequently, Slope became a common occurrence. Event of a slope collapse, landslides and mobility, not only nearby residents caused casualties and property losses, but also cause serious environmental impact. In this paper, combined with the actual example model, using ABAQUS software for slope stability were investigated by numerical simulation and result analysis, and development of rational treatment scheme. Through the study of the influence of the main factors for slope stability slope failure prevention, support reinforcement so as to provide a theoretical basis.

Abstract: As the most energy-saving hybrid system in the world, the full hybrid system has high research value. On the basis of the mechanical structural analysis of one new full hybrid system, studied its control strategy and analyzed the control algorithm for its power balance in the five working modes by means of simulated equivalent lever. It is hoped that this could provide technical support for the development of domestic full hybrid cars.