The combined effects of different overload ratios（OLRs）and nitriding process on fatigue crack growth（FCG）were analyzed.Steel compact tension specimens made of AISI 4140 steel were subjected to the plasma nitrifica...The combined effects of different overload ratios（OLRs）and nitriding process on fatigue crack growth（FCG）were analyzed.Steel compact tension specimens made of AISI 4140 steel were subjected to the plasma nitrification process using agas mixture of 50% N2 and 50% H2 at 500℃for 2h.Structural properties of the samples were studied by scanning electron microscopy,optical microscopy,microhardness testing and digital imaging.Plasma nitriding slowed down FCG,but the crack growth retardation caused by the overload was reduced when the OLR was 2.0and 2.5.Nitriding did not take effect when the OLR was 1.5and 3.0.展开更多
In this paper, a novel scheduling mechanism is proposed to handle the real-time overload problem by maximizing the cumulative values of three types of tasks： the soft, the hard and the imprecise tasks. The simulation...In this paper, a novel scheduling mechanism is proposed to handle the real-time overload problem by maximizing the cumulative values of three types of tasks： the soft, the hard and the imprecise tasks. The simulation results show that the performance of our presented mechanism in this paper is greatly improved, much better than that of the other three mechanisms： earliest deadline first （EDF）, highest value first （HVF） and highest density first （HDF）, under the same conditions of all nominal loads and task type proportions.展开更多
文摘The combined effects of different overload ratios（OLRs）and nitriding process on fatigue crack growth（FCG）were analyzed.Steel compact tension specimens made of AISI 4140 steel were subjected to the plasma nitrification process using agas mixture of 50% N2 and 50% H2 at 500℃for 2h.Structural properties of the samples were studied by scanning electron microscopy,optical microscopy,microhardness testing and digital imaging.Plasma nitriding slowed down FCG,but the crack growth retardation caused by the overload was reduced when the OLR was 2.0and 2.5.Nitriding did not take effect when the OLR was 1.5and 3.0.
基金supported by the Shanghai Applied Materials Foundation (Grant No.06SA18)
文摘In this paper, a novel scheduling mechanism is proposed to handle the real-time overload problem by maximizing the cumulative values of three types of tasks： the soft, the hard and the imprecise tasks. The simulation results show that the performance of our presented mechanism in this paper is greatly improved, much better than that of the other three mechanisms： earliest deadline first （EDF）, highest value first （HVF） and highest density first （HDF）, under the same conditions of all nominal loads and task type proportions.
