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Zhou X.-J.,Beijing Forestry University | Zhou X.-J.,Beijing Center for Physical and Chemical Analysis | Li K.,Beijing Forestry University | Fan H.,Beijing Forestry University | And 4 more authors.
Beijing Linye Daxue Xuebao/Journal of Beijing Forestry University | Year: 2015

We applied soxhlet extraction to obtain seed oil of 17 kinds of germplasm from 11 different areas of China, belonging to five varieties of the genus Perilla and then used GC-MS to analyze the amounts of oil as well as the composition and relative amounts of fatty acids. Fourteen fatty acids were indentified from P. frutescens seed oil. These were divided into two groups of six high level (0.8%) and eight low level (≤0.2%) amounts of fatty acids. For the first time 14-methyl-hexadecanoic acid (C17:0), 18 carbon diene acid (C18:2n3) and 23 carbon acid (C23:0) were reported in P. frutescens oil. The relative amount of α-linolenic acid was the highest with a range of 51.92% to 62.98%. Certain metabolic conversion relationships were detected among α-linolenic, linoleic and oleic acids. The results calculated with an external standard method for the amount of fatty acids in P. frutescens seeds implies that P. frutescens var. frutescens, among the five varieties investigated, is preferable as the raw material for P. frutescens oil, given its high rate of oil rate and its amount of α-linolenic acid. ©, 2015, Beijing Forestry University. All right reserved. Source

Ren F.,Northeast Petroleum University | Chen S.,Northeast Petroleum University | Yao Z.,Beijing Industrial Technician College
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2013

A flexible drill string in horizontal well was simplified as an axial load of elongated flexible beam. Nonlinear dynamic equations were established about the geometric large deformation, transverse vibration average equations of the beam were received by using the method of multiple scales. Due to the rotation speed and the axial force had the same role in the average equation, so nonlinear dynamic responses were analyzed by changing the rotating speed in the average equations. The bifurcation graphs for first and second order modes and phase diagram of different speeds were given. The analysis results show that the whole responses of system has gone through the process of cycle-chaos-twice the cycle, along with the response amplitudes there are jumping phenomena, and the amplitude of the rotating flexible beam actually is not infinite, but limited value in the resonance condition. Therefore, when the axial force changes, vibration of the flexible beam can be controlled by controlling its rotation speed quantitatively and qualitatively. Source

Yao M.,Beijing University of Technology | Zhang W.,Beijing University of Technology | Yao Z.,Beijing Industrial Technician College
Journal of Vibration and Acoustics, Transactions of the ASME | Year: 2015

This paper investigates the complicated dynamics behavior and the evolution law of the nonlinear vibrations of the simply supported laminated composite piezoelectric beam subjected to the axial load and the transverse load. Using the third-order shear deformation theory and the Hamilton's principle, the nonlinear governing equations of motion for the laminated composite piezoelectric beam are derived. Applying the method of multiple scales and Galerkin's approach to the partial differential governing equation, the four-dimensional averaged equation is obtained for the case of principal parametric resonance and 1:9 internal resonance. From the averaged equations obtained, numerical simulation is performed to study nonlinear vibrations of the laminated composite piezoelectric beam. The axial load, the transverse load, and the piezoelectric parameter are selected as the controlling parameters to analyze the law of complicated nonlinear dynamics of the laminated composite piezoelectric beam. Based on the results of numerical simulation, it is found that there exists the complex nonlinear phenomenon in motions of the laminated composite piezoelectric beam. In summary, numerical studies suggest that periodic motions and chaotic motions exist in nonlinear vibrations of the laminated composite piezoelectric beam. In addition, it is observed that the axial load, the transverse load and the piezoelectric parameter have significant influence on the nonlinear dynamical behavior of the beam. We can control the response of the system from chaotic motions to periodic motions by changing these parameters. Copyright © 2015 by ASME. Source

Lv F.,Beijing University of Chemical Technology | Liang H.,Beijing University of Chemical Technology | Yuan Q.,Beijing University of Chemical Technology | Li C.,Beijing Industrial Technician College
Food Research International | Year: 2011

The aim of this study was to evaluate the antimicrobial efficacy of selected plant essential oil (EO) combinations against four food-related microorganisms. Ten EOs were initially screened against Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Saccharomyces cerevisiae using agar disk diffusion and broth dilution methods. The highest efficacy against all the tested strains was shown when testing the oregano EO. EOs of basil and bergamot were active against the Gram-positive bacteria (S. aureus and B. subtilis), while perilla EO strongly inhibited the growth of yeast (S. cerevisiae). The chemical components of selected EOs were also analyzed by GC/MS. Phenols and terpenes were the major antimicrobial compounds in oregano and basil EOs. The dominant active components of bergamot EO were alcohols, esters and terpenes. For perilla EO, the major active constituents were mainly ketones. The checkerboard method was then used to investigate the antimicrobial efficacy of EO combinations by means of the fractional inhibitory concentration index (FICI). Based on an overall consideration of antimicrobial activity, organoleptic impact and cost, four EO combinations were selected and their MIC values were listed as follows: oregano-basil (0.313-0.313 μl/ml) for E. coli, basil-bergamot (0.313-0.156 μl/ml) for S. aureus, oregano-bergamot (0.313-0.313 μl/ml) for B. subtilis and oregano-perilla (0.313-0.156 μl/ml) for S. cerevisiae. Furthermore, the mechanisms of the antimicrobial action of EO combinations to the tested organisms were studied by the electronic microscopy observations of the cells and the measurement of the release of cell constituents. The electron micrographs of damaged cells and the significant increase of the cell constituents' release demonstrated that all EO combinations affected the cell membrane integrity. © 2011 Elsevier Ltd. Source

Ren F.,Northeast Petroleum University | Chen S.,Northeast Petroleum University | Yao Z.,Beijing Industrial Technician College
Applied Mechanics and Materials | Year: 2012

This paper studies the complex transverse vibration behavior of drill string. The drill string was simplified as flexible rotation beam, and drill string of complex load was simplified for flexible rotation beam system. The nonlinear dynamic equations of flexible rotation beam is established and the complex dynamic response of flexible rotation beam in resonance case is analyzed by using method of nonlinear dynamics method. Research result show that the chaotic responses are sensitive to the revolving speed, the nonlinear oscillation of drilling string can be controlled by changing the rotating speed. This study has guiding significance to keep sidewall stability in the process of horizontal wells of sidetrack, improve the drilling rate and reduce the cost of the drilling. © (2012) Trans Tech Publications, Switzerland. Source

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