Computational Simulation of Comb-plate Expansion Joints

A finite element model of the expansion Joints’ common damages of a novel comb-plate by using the finite element software ABAQUS is presented in this paper. The mechanical behavior of expansion Joints is analyzed to verify the weak parts of it. The research results provide a reference for the design of the comb-plate expansion Joints

Statistical Properties of Multiple Optical Emission Components in Gamma-Ray Bursts and Implications

Well-sampled optical lightcurves of 146 gamma-ray bursts (GRBs) are complied from the literature. Multiple optical emission components are extracted with power-law function fits to these lightcurves. We present a systematical analysis for statistical properties and their relations to prompt gamma-ray emission and X-ray afterglow for each component. We show that peak luminosity in the prompt and late flares are correlated and the evolution of the peak luminosity may signal the evolution of the accretion rate. No tight correlation between the shallow decay phase/plateau and prompt gamma-ray emission is found. Assuming that they are due to a long-lasting wind injected by a compact object, we show that the injected behavior favors the scenarios of a long-lasting wind after the main burst episode. The peak luminosity of the afterglow onset is tightly correlated with Eiso, and it is dimmer as peaking later. Assuming that the onset bump is due to the fireball deceleration by the external medium, we examine the Gamma_0-Eiso relation and find that it is confirmed with the current sample. Optical re-brightening is observed in 30 GRBs in our sample. It shares the same relation between the width and the peak time as found in the onset bump, but no clear correlation between the peak luminosity and Eiso as observed in the onset bumps is found. Although its peak luminosity also decays with time, the slope is much shallower than that of the onset peak. We get L t^{-1}_{p}$, being consistent with off-axis observations to an expanding external fireball in a wind-like circum medium. The late re-brightening may signal another jet component. Mixing of different emission components may be the reason for the observed chromatic breaks in different energy bands.Comment: 10 pages, 5 figures, to be published by IJMPD (Proceedings of "The Third Galileo - Xu Guangqi meeting", Beijing, October 11-15, 2011

Analysis on the Symbolic Effect of Calligraphy Landscape of Tourism Scenic Spots: The Case of China

Calligraphy landscape is a kind of special cultural landscape and symbols with Chinese characteristics, and has become an important type of tourism landscape in scenic spots. This paper takes calligraphy landscape of two famous tourism scenic spots in Guilin city of China as a study case, measures its symbolic effect with 5-point Likert scale. The result shows that calligraphy landscape receives high cognition and appreciation interest from tourists. Calligraphy landscape has certain symbolic effect on tourists in the dimensions of calligraphy appreciation, cultural symbol and landscape metaphor. Significant differences of symbolic effect of calligraphy landscape exist in the dimension of calligraphy appreciation, but not in the dimensions of cultural symbol and landscape metaphor. Symbolic effect research of calligraphy landscape provides theoretical guidance to revealing the relationship among people’s sense of place, environmental behavior and calligraphy landscape. The study has practical reference significance for designing calligraphy landscape and creating cultural atmosphere in tourism scenic spot

Origin of Scaling Behavior of Protein Packing Density: A Sequential Monte Carlo Study of Compact Long Chain Polymers

Single domain proteins are thought to be tightly packed. The introduction of voids by mutations is often regarded as destabilizing. In this study we show that packing density for single domain proteins decreases with chain length. We find that the radius of gyration provides poor description of protein packing but the alpha contact number we introduce here characterize proteins well. We further demonstrate that protein-like scaling relationship between packing density and chain length is observed in off-lattice self-avoiding walks. A key problem in studying compact chain polymer is the attrition problem: It is difficult to generate independent samples of compact long self-avoiding walks. We develop an algorithm based on the framework of sequential Monte Carlo and succeed in generating populations of compact long chain off-lattice polymers up to length $N=2,000$. Results based on analysis of these chain polymers suggest that maintaining high packing density is only characteristic of short chain proteins. We found that the scaling behavior of packing density with chain length of proteins is a generic feature of random polymers satisfying loose constraint in compactness. We conclude that proteins are not optimized by evolution to eliminate packing voids.Comment: 9 pages, 10 figures. Accepted by J. Chem. Phy

Study of an Improved Fuzzy Direct Torque Control of Induction Motor

The conventional direct torque control will inevitably produce torque ripple because of its way of flux estimates. For the purpose of handling this problem, a new control strategy was presented in this paper. This strategy combined subdivides control with voltage vector and fuzzy logic control in traditional direct torque control. In this model, the fuzzy logic combined the phase angle of the flux, the flux error and torque error as fuzzy variables and classified these fuzzy variables, in order to optimize the choice of voltage space vector, and the same time the traditional PID regulator is replaced by a fuzzy regulator. Simulation results show that, a great improvement torque responses , a great reduction of torque ripples is achieved and the strategy has a better dynamic and steady performance, especially in low-speed area

Study on coalface stray current safety early warning based on ANFIS

AbstractBy analyzing the DC traction supply system in coal mine, we confirmed the following four parameters to be the characteristic parameters of workface stray current safe early warning, that is, the leakage current of contacting line, resistance of insulating splint, the distance between workface and subtraction substation and the stray voltage of contacting line. After that, we developed a safety early warning model of coal mining workface stray current danger grade with ANFIS as its core, choosing data sets measured online to do the training and early warning of safe early warning model. Results indicate that the model can be able to complete safety early warning of workface stray current. Besides, a monitoring and early warning system of stray current was introduced