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Tian X.,Shandong Polytechnic University | Li C.X.,Industry Weapon
Applied Mechanics and Materials | Year: 2013

Consider the rod on elastic foundation. Its discrete model is the simply connected spring-mass system with partial mass connected to the ground. The inverse mode problem of constructing the physical elements of the system from two eigenpairs, the spring stiffness of the system is considered. The necessary and sufficient conditions for constructing a physical realizable system with positive mass and stiffness elements are established. If these conditions are satisfied, the rod on the elastic foundation may be constructed uniquely. The numerical methods and examples are given finally. © (2013) Trans Tech Publications, Switzerland. Source


Tian X.,Shandong Polytechnic University | Li C.X.,Industry Weapon
Applied Mechanics and Materials | Year: 2013

Consider the simply connected spring-mass system with partial mass connected to the ground. The inverse mode problem of constructing the physical elements of the system from two eigenpairs, the grounding spring stiffness and total mass of the system is considered. The necessary and sufficient conditions for constructing a physical realizable system with positive mass and stiffness elements are established. If these conditions are satisfied, the grounding spring-mass system may be constructed uniquely. The numerical methods and examples are given finally. © (2013) Trans Tech Publications, Switzerland. Source


Bian L.,Northwest University, China | Yang J.,Northwest University, China | Yang J.,Industry Weapon | Sun Y.,Northwest University, China
Biomedical Chromatography | Year: 2015

Monosialotetrahexosylganglioside (GM1), one of glycosphingolipids containing sialic acid, plays particularly important role in fighting against paralysis, dementia and other diseases caused by brain and nerve damage. In this work, a simple and highly efficient method with high yield was developed for isolation and purification of GM1 from pig brain. The method consisted of an extraction by chloroform-methanol-water and a two-step chromatographic separation by DEAE-Sepharose Fast Flow anion-exchange medium and Sephacryl S-100 HR size-exclusion medium. The purified GM1 was proved to be homogeneous and had a purity of >98.0% by high-performance anion-exchange and size-exclusion chromatography. The molecular weight was 30.0kDa by high-performance size-exclusion chromatography and 1546.9Da by electrospray ionization mass spectrometry. The chromogenic reaction by resorcinol-hydrochloric acid solution indicated that the purified GM1 showed a specific chromogenic reaction of sialic acid. Through this isolation and purification program, ~1.0mg of pure GM1 could be captured from 500g wet pig brain tissue and the yield of GM1 was around 0.022%, which was higher than the yields by other methods. The method may provide an alternative for isolation and purification of GM1 in other biological tissues. © 2015 John Wiley & Sons, Ltd. Source


Wang F.S.,Northwestern Polytechnical University | Ding N.,Industry Weapon | Liu Z.Q.,Northwestern Polytechnical University | Ji Y.Y.,Northwestern Polytechnical University | Yue Z.F.,Northwestern Polytechnical University
Composite Structures | Year: 2014

Ablation damage characteristic of carbon fiber/epoxy composite laminate suffered from lightning strike was studied by the coupled thermal-electrical-structural analysis and element deletion. Residual strength of composite laminate after lightning strike ablation was globally predicted by Hashin criterion. Results show that lightning ablation effects decrease with the increasing electrical conductivity or specific heat, while thermal conductivity has little influence on them. Residual strength of composite laminate is generally greater than 80% and decreases with the increasing peak current or ratio of time to the maximum current and that to 50% of the maximum current under static tensile load. The work can provide detailed technical support for lightning damage evaluation and residual strength prediction of aircraft carbon fiber/epoxy composite laminates in theory, which is seldom reported compared with lightning test researches available up to now. © 2014 Elsevier Ltd. Source


Tian X.,University of Science and Technology of China | Li C.-X.,Industry Weapon
Progress in Civil, Architectural and Hydraulic Engineering - Selected Papers of the 4th International Conference on Civil, Architectural and Hydraulic Engineering, ICCAHE 2015 | Year: 2016

The effects of adding spring to a beam on its frequencies are investigated for cantilever beam. Consider two systems: cantilever beam and the same cantilever beam added additional spring. By using two natural frequencies of each system, we identify the structural parameter of the original system. The method is nondestructive. The stiffness of the additional springs is known. Given the natural frequencies of each system, the stiffness of the additional springs and the total mass of the beam, the bending rigidity and density of cantilever beam are reconstructed. The solution of the problem is given and the conditions for the construction of the beam are derived. It is not iterative and therefore demands a modest computational effort. © 2016 Taylor & Francis Group, London. Source

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