In this letter,Fe_2O_3 UFP(Ultrafine Particles)hydrosol and organosol with high third order optical nonlinear susceptibility(3)have been reported for the first time. The surfacial modification of Fe_2O_3 UFP with dode...In this letter,Fe_2O_3 UFP(Ultrafine Particles)hydrosol and organosol with high third order optical nonlinear susceptibility(3)have been reported for the first time. The surfacial modification of Fe_2O_3 UFP with dodecylbenzenesulfonate ions(DBS)can enhance the nonlinear optical response through interfacial confinement of electron motion. The involved mechanism is discussed.展开更多
It is proved experimentally that the relaxation and complex electrochemical oscillations could be induced by inserting external resistors in the electrochemical systems in which bistability could be found.FeH2SO4 syst...It is proved experimentally that the relaxation and complex electrochemical oscillations could be induced by inserting external resistors in the electrochemical systems in which bistability could be found.FeH2SO4 system,in which the Fe electrode exhibited bistability within the potential range of 0.309 V～0.406V(vs.SCE),was chosen in our experiments.When the applied potential was 0.340 V and no external resistor was inserted,no oscillations could be observed.While the applied potential was kept at 0.340 V and an appropriate external resistor was connected in series to the electrochemical system,relaxation or complex oscillations appeared.Upon the external resistance increased,the amplitude of the oscillations decreased gradually.The inducement of electrochemical oscillations is helpful to understand the mechanism of the metals dissolution and passive,and to control the dynamic behavior of some electrochemical systems.展开更多
目的基于BP神经网络具有自学习、自训练和输出预测的功能,将其应用于热喷涂过程中的参数优化问题。方法依托高效能超音速等离子喷涂系统实验平台,以Fe基合金粉末为喷涂材料,将等离子喷涂中的主气流量、电功率和喷涂距离作为模型输入,涂...目的基于BP神经网络具有自学习、自训练和输出预测的功能,将其应用于热喷涂过程中的参数优化问题。方法依托高效能超音速等离子喷涂系统实验平台,以Fe基合金粉末为喷涂材料,将等离子喷涂中的主气流量、电功率和喷涂距离作为模型输入,涂层沉积速率和硬度作为模型输出,不断调整隐含层节点个数,最终建立3-7-2网络结构的BP神经网络以优化工艺参数。利用优化出的工艺参数制备Fe基合金涂层,测试其性能,并计算误差。结果神经网络优化出的最优喷涂工艺参数为:主气流量96L/min,电功率56 k W,喷涂距离95 mm。采用该工艺参数制备涂层,涂层增厚实测平均值为360μm,硬度为672HV0.3,而模型的预测值分别为332μm和611HV0.3,与预测值的相对误差分别为7.8%和9.1%。结论 BP神经网络对等离子喷涂参数优化问题的拟合精度比较高,误差在可以接受的范围之内。将BP神经网络运用于热喷涂工艺参数的优化具有科学性和可操作性。展开更多
基金This project is sponsored by National Science Fundation.
文摘In this letter,Fe_2O_3 UFP(Ultrafine Particles)hydrosol and organosol with high third order optical nonlinear susceptibility(3)have been reported for the first time. The surfacial modification of Fe_2O_3 UFP with dodecylbenzenesulfonate ions(DBS)can enhance the nonlinear optical response through interfacial confinement of electron motion. The involved mechanism is discussed.
文摘It is proved experimentally that the relaxation and complex electrochemical oscillations could be induced by inserting external resistors in the electrochemical systems in which bistability could be found.FeH2SO4 system,in which the Fe electrode exhibited bistability within the potential range of 0.309 V～0.406V(vs.SCE),was chosen in our experiments.When the applied potential was 0.340 V and no external resistor was inserted,no oscillations could be observed.While the applied potential was kept at 0.340 V and an appropriate external resistor was connected in series to the electrochemical system,relaxation or complex oscillations appeared.Upon the external resistance increased,the amplitude of the oscillations decreased gradually.The inducement of electrochemical oscillations is helpful to understand the mechanism of the metals dissolution and passive,and to control the dynamic behavior of some electrochemical systems.
文摘目的基于BP神经网络具有自学习、自训练和输出预测的功能,将其应用于热喷涂过程中的参数优化问题。方法依托高效能超音速等离子喷涂系统实验平台,以Fe基合金粉末为喷涂材料,将等离子喷涂中的主气流量、电功率和喷涂距离作为模型输入,涂层沉积速率和硬度作为模型输出,不断调整隐含层节点个数,最终建立3-7-2网络结构的BP神经网络以优化工艺参数。利用优化出的工艺参数制备Fe基合金涂层,测试其性能,并计算误差。结果神经网络优化出的最优喷涂工艺参数为:主气流量96L/min,电功率56 k W,喷涂距离95 mm。采用该工艺参数制备涂层,涂层增厚实测平均值为360μm,硬度为672HV0.3,而模型的预测值分别为332μm和611HV0.3,与预测值的相对误差分别为7.8%和9.1%。结论 BP神经网络对等离子喷涂参数优化问题的拟合精度比较高,误差在可以接受的范围之内。将BP神经网络运用于热喷涂工艺参数的优化具有科学性和可操作性。
