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Liping Wang,Zhaokun Zhang,Zhufeng Shao 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.2
This paper presents a 3-RPaS (R and S denote the revolute and spherical joint, pa denotes the parallelogram) parallel manipulator with two-rotational-degrees-of-freedom (2R1T) and one-translational-degree-of-freedom motion. By introducing parallelograms and an innovative driving module, the 3-RPaS manipulator can change the transmission path of the driving and reaction forces, and achieves 27 actuation modes. The kinematic performance of the manipulator under different actuation modes is analyzed with the indices that are defined based on matrix orthogonal degree. Comparative analysis indicates that the kinematic performance of the manipulator varies significantly in different actuation modes. A reasonable selection of actuation modes can effectively improve the kinematic performance and eliminate singularities. The concept of optimal actuation mode and the implementation approach of actuation mode conversion are discussed and analyzed for kinematics promotion. The kinematic performance of the manipulator is greatly improved with optimal actuation modes, without changing the topology structure and dimensional parameters.
Nematicidal effect of volatiles produced by Trichoderma sp.
Zhongshan Yang,ZeFen Yu,,Liping Lei,Zhenyuan Xia,Li Shao,Ke Qin Zhang,Guo Hong Li 한국응용곤충학회 2012 Journal of Asia-Pacific Entomology Vol.15 No.4
Trichoderma is an important biocontrol agent that produces metabolites harmful to nematodes. We investigated the volatile organic compounds (VOCs) of Trichoderma sp. YMF 1.00416 and examined their abilities to kill nematodes. Chemical investigations of the VOCs from this strain led to the isolation and identification of three metabolites: a new compound, 1β-vinylcyclopentane-1α,3α-diol (1) and two known metabolites, 6-pentyl-2H-pyran-2-one (2) and 4-(2-hydroxyethyl)phenol (3). Nematicidal activity assays showed that compound 2 was nematicidal, and killed >85% of Panagrellus redivivus, Caenorhabditis elegans,and Bursaphelenchus xylophilus in 48 h at 200 mg/L in a 2 mL vial. Our results will help identify new nematicides.