To investigate the cage stability of high-speed oil-lubricated angular contact ball bearings, a dynamic model of cages is developed on the basis of Gupta’s and Meeks’ work. The model can simulate the cage motion und...To investigate the cage stability of high-speed oil-lubricated angular contact ball bearings, a dynamic model of cages is developed on the basis of Gupta’s and Meeks’ work. The model can simulate the cage motion under oil lubrication with all six degrees of freedom. Particularly, the model introduces oil-film damping and hysteresis damping, and deals with the collision contact as imperfect elastic contact. In addition, the effects of inner ring rotational speed, the ratio of pocket clearance to guiding clearance and applied load on the cage stability are investigated by simulating the cage motion with the model. The results can provide a theoretical basis for the design of ball bearing parameters.展开更多
Effects of nano SbSbS4particles on contact fatigue life of a steel ball were evaluated on a self-made ball-rod contact fatigue tester. The anti-fatigue mechanisms of SbSbS4 additive were analyzed by means of SEM and E...Effects of nano SbSbS4particles on contact fatigue life of a steel ball were evaluated on a self-made ball-rod contact fatigue tester. The anti-fatigue mechanisms of SbSbS4 additive were analyzed by means of SEM and EDAX. It was shown that, when the grease contained SbSbS4, contact fatigue life was improved compared with that of base grease. Nanoparticle absorption action, nanoparticle infiltration action, and extreme pressure and anti-friction performance, explained why SbSbS4 increased the contact fatigue life of the steel ball tested.展开更多
Rotor systems supported by angular contact ball bearings are complicated due to nonlinear Hertzian contact force. In this paper, nonlinear bearing forces of ball bearing under five-dimensional loads are given, and 5-D...Rotor systems supported by angular contact ball bearings are complicated due to nonlinear Hertzian contact force. In this paper, nonlinear bearing forces of ball bearing under five-dimensional loads are given, and 5-DOF dynamic equations of a rigid rotor ball bearing system are established. Continuation-shooting algorithm for periodic solutions of the nonlinear non-autonomous dynamic system and Floquet multipliers of the system are used. Furthermore, the bifurcation and stability of the periodic motion of the system in different parametric domains are also studied. Results show that the bifurcation and stability of period-1 motion vary with structural parameters and operating parameters of the rigid rotor ball bearing system. Avoidance of unbalanced force and bending moment, appropriate initial contact angle, axial load and damping factor help enhance the unstable rotating speed of period-1 motion.展开更多
A pathogenic bacterium （S636）, identified as Streptococcus iniae, was isolated from turbot （Scophthalrnus maximus） in 2005. We immunized turbot with formalin-killed S. iniae four times （on days 1, 14, 21, and 28...A pathogenic bacterium （S636）, identified as Streptococcus iniae, was isolated from turbot （Scophthalrnus maximus） in 2005. We immunized turbot with formalin-killed S. iniae four times （on days 1, 14, 21, and 28） by intraperitoneal inoculation. After each vaccination, we obtained serum samples and isolated the lymphocytes from the peripheral blood, spleen, pronephros, and mesonephros. We measured surface Ig-positive （sIg＋） lymphocytes and serum antibody levels from these organs using flow cytometry and enzyme-linked immunosorbent assay （ELISA）, respectively, using monoclonal antibodies against turbot immunoglohulin. We confirmed that the antibody reacted with both the surface and plasma Ig by confocal laser scanning microscopy and electron microscopy. The percentage of sIg＋ in the lymphocytes increased following each successive vaccination. The mean percentage increased from 31.96% （control） to 37.49%, 38.36%, 42.9%, and 51.63% in the peripheral blood; from 27.09% to 36.63%, 36.81%, 39.28%, and 46.0% in the spleen; from 22.2% to 28.99%, 29.21%, 32.83%, and 41.58% in pronephros; and from 18.12% to 22.17%, 22.45%, 25.69%, and 31.68% in the mesonephros. The ELISA results were consistent with these results. Both the total and specific antibody levels increased with each vaccination. The mean OD value of the specific antibody assay increased from 0.094, to 0.269, 0.283, 0.333, and 0.421; for total antibody the mean OD value increased from 0.133, to 0.292, 0.323, 0.413, and 0.527.展开更多
基金Supported by National Key Technology Research and Development Program of China during the 11th Five-Year Plan Period (No. JPPT-115-189)National Natural Science Foundation of China (No. 50975033)
文摘To investigate the cage stability of high-speed oil-lubricated angular contact ball bearings, a dynamic model of cages is developed on the basis of Gupta’s and Meeks’ work. The model can simulate the cage motion under oil lubrication with all six degrees of freedom. Particularly, the model introduces oil-film damping and hysteresis damping, and deals with the collision contact as imperfect elastic contact. In addition, the effects of inner ring rotational speed, the ratio of pocket clearance to guiding clearance and applied load on the cage stability are investigated by simulating the cage motion with the model. The results can provide a theoretical basis for the design of ball bearing parameters.
基金Sponsored by State Key Laboratory of Solid Lubrication Opening Foundation(Grant No.0303).
文摘Effects of nano SbSbS4particles on contact fatigue life of a steel ball were evaluated on a self-made ball-rod contact fatigue tester. The anti-fatigue mechanisms of SbSbS4 additive were analyzed by means of SEM and EDAX. It was shown that, when the grease contained SbSbS4, contact fatigue life was improved compared with that of base grease. Nanoparticle absorption action, nanoparticle infiltration action, and extreme pressure and anti-friction performance, explained why SbSbS4 increased the contact fatigue life of the steel ball tested.
基金Supported by National Natural Science Foundation of China (No.50905061)the Fundamental Research Funds for Central Universities
文摘Rotor systems supported by angular contact ball bearings are complicated due to nonlinear Hertzian contact force. In this paper, nonlinear bearing forces of ball bearing under five-dimensional loads are given, and 5-DOF dynamic equations of a rigid rotor ball bearing system are established. Continuation-shooting algorithm for periodic solutions of the nonlinear non-autonomous dynamic system and Floquet multipliers of the system are used. Furthermore, the bifurcation and stability of the periodic motion of the system in different parametric domains are also studied. Results show that the bifurcation and stability of period-1 motion vary with structural parameters and operating parameters of the rigid rotor ball bearing system. Avoidance of unbalanced force and bending moment, appropriate initial contact angle, axial load and damping factor help enhance the unstable rotating speed of period-1 motion.
基金Supported by the National Basic Research Program of China (973 Program, No 2006CB101806)the High Technology Research and Development Program of China (863 Program,No 2006AA100306)the National Natural Science Fundation of China (No 30771648)
文摘A pathogenic bacterium （S636）, identified as Streptococcus iniae, was isolated from turbot （Scophthalrnus maximus） in 2005. We immunized turbot with formalin-killed S. iniae four times （on days 1, 14, 21, and 28） by intraperitoneal inoculation. After each vaccination, we obtained serum samples and isolated the lymphocytes from the peripheral blood, spleen, pronephros, and mesonephros. We measured surface Ig-positive （sIg＋） lymphocytes and serum antibody levels from these organs using flow cytometry and enzyme-linked immunosorbent assay （ELISA）, respectively, using monoclonal antibodies against turbot immunoglohulin. We confirmed that the antibody reacted with both the surface and plasma Ig by confocal laser scanning microscopy and electron microscopy. The percentage of sIg＋ in the lymphocytes increased following each successive vaccination. The mean percentage increased from 31.96% （control） to 37.49%, 38.36%, 42.9%, and 51.63% in the peripheral blood; from 27.09% to 36.63%, 36.81%, 39.28%, and 46.0% in the spleen; from 22.2% to 28.99%, 29.21%, 32.83%, and 41.58% in pronephros; and from 18.12% to 22.17%, 22.45%, 25.69%, and 31.68% in the mesonephros. The ELISA results were consistent with these results. Both the total and specific antibody levels increased with each vaccination. The mean OD value of the specific antibody assay increased from 0.094, to 0.269, 0.283, 0.333, and 0.421; for total antibody the mean OD value increased from 0.133, to 0.292, 0.323, 0.413, and 0.527.
