Chongqing, China
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Huang H.,ChongqingUniversity | Guo T.,Chongqing University | Li P.,Chongqing University | Sun Z.-W.,Chongqing University
WCTE 2016 - World Conference on Timber Engineering | Year: 2016

Chuan-Dou style wood construction is one of the most widely used structure types in Chinese history. There were some common failure modes been found after some major earthquake events in past few decades, it is urgent to study its aseismic mechanism and retrofitting methods to guide engineering practice. This paper presents the experimental results of low-cyclic reversed loading tests on two full-scale Chuan-Dou style wood frames. Seismic behaviors, such as hysteretic curves, skeleton curves, degeneration of strength and rigidity, deformation capacity and energy dissipation capacity, are summarized, experimental results shows that there is significant pinching phenomenon in the hysteresis curves, Chuan-Dou style wood frames exhibit reasonable energy dissipation capacity and deformation capability, but stiffness of mortise-tenon joints is low and its stiffness degrade significantly after subsequent load cycles, which induced large deflection of wood frames. Finally, some suggestions were presented to improve the seismic performance of Chuan-Dou style wood construction.

Liu Y.,National Key Laboratory of Gas Disaster Detecting | Liu Y.,China Coal Technology and Engineering Co. | Liu Y.,ChongqingUniversity | Wen G.,National Key Laboratory of Gas Disaster Detecting | And 6 more authors.
Disaster Advances | Year: 2012

The mechanical property of gas-filled coal is a fundamental research in the field of gas disaster prevention. The original gas-filled coal is a typical non-uniform and multiphase medium, which is composed of the porous solid skeleton with non-uniform spatial distribution, free gas in the pore and the quasi-liquid adsorption gas presented in the pore surface. Changes of behaviors and mechanical performance are very complex. In order to describe the physical and mechanical properties of gas-filled coal from the perspectives of mathematics and mechanics, we established a meso-statistical damage constitutive model of gas-filled coal adopting the research method of meso-damge mechanics and proposed the solving approach to model parameters by using acoustic emission data obtained from meso-mechanical experiments of gas-filled coal. The model was established fully considering the characteristics of solid and gas coupling of gas-filled coal based on Weibull theory and Mohr-Coulomb rule and the effective stress principle of solid-gas coupling of gas-filled coal was taken into account. Advantages of this model are: reflecting the properties of microscopic inhomogeneous and nonlinear deformations, combining damage variable and damage evolution equation with acoustic emission, which provides a comparatively clear physical engineering background.

Liu J.H.,Guizhou Normal University | Wang H.T.,ChongqingUniversity
European Physical Journal B | Year: 2015

Topological quantum phase transitions are numerically investigated in a spin-1/2 dimerized and frustrated Heisenberg chain by using infinite matrix product state representation with the infinite time evolving block decimation method. Quantum fidelity approach is employed to detect the degenerate ground states and quantum phase transitions. By calculating the long-range string order parameters, we find two topological Haldane phases characterized by two long-range string orders. Also, continuous and discontinuous behaviors of von Neumann entropy show that phase transitions between two topological Haldane phases are topologically continuous and discontinuous quantum phase transitions. For the topologically continuous phase transition, the central charge at the critical point is obtained as c = 1, which means that the topologically continuous quantum phase transition belongs to the Gaussian universality class. © 2015, EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.

Sun W.,ChongqingUniversity | Shao M.,ChongqingUniversity | Ren H.,University of Minnesota | Xiao D.,ChongqingUniversity | And 5 more authors.
Journal of Physical Chemistry C | Year: 2015

A type of relay station for electron transfer in proteins, three piece five electron bonding, is introduced in this paper, which is also first proposed here. The ab initio calculations predict the formation of S:II ∴S虠S∴II:S resonance binding with an aromatic ring located in the middle of two sulfur containing groups, which may participate in electron hole transport in proteins. These special structures can lower the local ionization energies to capture electron holes efficiently and may be easily formed and broken because of their proper binding energies. In addition, the UV vis spectra provide evidence of the formations of the three piece five electron binding. The cooperation of three adjacent pieces may be advantage to promote electron transfer a longer distance. © 2015 American Chemical Society.

Lin M.,ChongqingUniversity | Chen S.,Chongqing University
IEEE Transactions on Consumer Electronics | Year: 2013

Because NAND flash memory provides the outof-place update scheme to address its erase-before-write hardware constraint, garbage collection policy is included in the flash-aware file systems and flash translation layer (FTL) to reclaim garbage and obtain free space. In this paper, an efficient and intelligent garbage collection policy is proposed for NAND flash-based consumer electronics, which is called EIGC. EIGC introduces an efficient grey prediction model for forecasting the future I/O workload during the next garbage collection operation execution time interval and determines the number of victim blocks that should be selected for evicting according to the predicted I/O workload. In order to reduce the cleaning cost in terms of the cost for copying the valid pages to the free space of NAND flash memory and improve the degree of wear leveling, an efficient victim block selection scheme is included in the proposed EIGC policy. Trace-driven simulations show that the proposed EIGC policy is superior to the state-of-the-art policies in terms of the number of copy operations, the number of erase operations, and the degree of wear leveling. © 2013 IEEE.

Yu X.G.,ChongqingUniversity | Hu L.,ChongqingUniversity | Gao C.,ChongqingUniversity | Wu G.L.,ChongqingUniversity
Advanced Materials Research | Year: 2014

The effect of the limestone on the strength of the foam concrete is studied in this paper. The dry density of the foam concrete used in this experiment is 500 kg/m3 , which is largely used in foam concrete for heat preservation in building. The experimental results reveal that the content of the limestone has great influence on the 3 d, 7 d and 28 d compressive strength and flexural strength of the foam concrete, but the fineness of the limestone has little influence on the 3 d, 7 d and 28 d compressive strength and flexural strength of the foam concrete, when the specific surface area is in the range of 210 cm2 /g-440 cm2 /g. © (2014) Trans Tech Publications, Switzerland.

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