We fabricate and characterize Au nanoparticle-aggregated nanowires by using the nano meniscus-induced colloidal stacking method. The Au nanoparticle solution ejects with guidance of nanopipette/quartz tuning fork-base...We fabricate and characterize Au nanoparticle-aggregated nanowires by using the nano meniscus-induced colloidal stacking method. The Au nanoparticle solution ejects with guidance of nanopipette/quartz tuning fork-based atomic force microscope in ambient conditions, and the stacking particles form Au nanoparticle-aggregated nanowire while the nozzle retracts from the surface. Their mechanical properties with relatively low elastic modulus are in situ investigated by using the same apparatus.展开更多
采用多层感知器模型、随机森林模型为第一层子模型,极端树模型为第二层元模型,建立基于Stacking集成机器学习的波浪预报算法,并引入邻域平均法抑制在拐点处产生的数值震荡。以长江口外海2016年1-9月的风速和中国近海波高数据为数据源,...采用多层感知器模型、随机森林模型为第一层子模型,极端树模型为第二层元模型,建立基于Stacking集成机器学习的波浪预报算法,并引入邻域平均法抑制在拐点处产生的数值震荡。以长江口外海2016年1-9月的风速和中国近海波高数据为数据源,利用机器学习风速与有效波高之间的关系,将2016年10-11月的风速、波高数据用于预报结果的对比分析,预报前45 d R^2拟合优度达到0.97以上,平均误差最大值为0.08 m,平均相对误差最大值为0.05,预报结果与波浪谱模型结果趋势一致,准确度较高;预报结果后15 d误差增长较快,这与训练集数据中寒潮浪占比较少有关。展开更多
The influence of temperature on the hydrogen diffusion behavior in X80 pipeline steel during stacking for slow cooling was studied using electrochemical penetration method, the temperature field and the hydrogen diffu...The influence of temperature on the hydrogen diffusion behavior in X80 pipeline steel during stacking for slow cooling was studied using electrochemical penetration method, the temperature field and the hydrogen diffusion in this pipeline steel during stacking for slow cooling were simulated by ABAQUS finite element method （FEM） software. The results show that in this process there is a reciprocal relationship between the natural logarithm of hydrogen diffusion coefficient and temperature. The cooling rate decreases gradually with the increase of steel plate thickness. The hydrogen content is higher at high temperature （500-400 ℃） than that in low temperature region （300-100 ℃）. The FEM simulation results are consistent with the experimental ones, and the model can be used to predict the hydrogen diffusion behavior in industrial production of X80 pipeline steel.展开更多
The influence of carbon content on the stacking fault energy （SFE） of Fe-20Mn-3Cu twinning-induced plasticity （TWIP） steel was investigated by means of X-ray diffraction peak-shift method and thermodynamic modelin...The influence of carbon content on the stacking fault energy （SFE） of Fe-20Mn-3Cu twinning-induced plasticity （TWIP） steel was investigated by means of X-ray diffraction peak-shift method and thermodynamic modeling. The experimental result indicated that the stacking fault probability decreases with increasing carbon addition, the SFE increases linearly when the carbon content in mass percent is between 0.23 M and 1.41%. The thermody namic calculation results showed that the SFE varied from 22.40 to 29.64 mJ ~ m 2 when the carbon content in mass percent changes from 0.23 % to 1.41%. The XRD analysis revealed that all steels were fully austenitic before and after deformation, which suggested that TWIP effect is the predominant mechanism during the tensile deformation process of Fe-20Mn-3Cu-XC steels.展开更多
Implementation of novelγ/γ'Co-based superalloys with higher strength and improved creep durability is a challenging task for researchers.The lack of atomic-level understanding of plastic deformation behavior has...Implementation of novelγ/γ'Co-based superalloys with higher strength and improved creep durability is a challenging task for researchers.The lack of atomic-level understanding of plastic deformation behavior has seriously limited the exploration of the full capacity of Co-based alloys.We put forward a comprehensive study of generalized stacking fault energies by first principles to explore the effect of Ni and Al/W on the plastic deformation mechanism ofγ'precipitates in Co-based superalloys.It is found that alloying Ni and adjusting Al/W obviously change the dislocation glide and twinning nucleation in theγ'precipitates by altering the stable fault energies and the unstable fault energy barriers.Excessive addition of either Ni or W deteriorates the strength even the stability of alloys.The ratio of effective planar fault energy(ΔEp)bridges intrinsic energy barriers and various deformation mechanisms of superalloys at elevated temperatures.Except for alloying effects,the grain orientation also significantly governs the operation of the plastic deformation of superalloys.Our theoretical results agree with the available measurements and well capture the observed phenomena in experiments.展开更多
Molecular dynamics(MD) simulations are performed to investigate the effects of stress on generalized stacking fault(GSF) energy of three fcc metals(Cu, Al, and Ni). The simulation model is deformed by uniaxial tension...Molecular dynamics(MD) simulations are performed to investigate the effects of stress on generalized stacking fault(GSF) energy of three fcc metals(Cu, Al, and Ni). The simulation model is deformed by uniaxial tension or compression in each of [111], [11-2], and [1-10] directions, respectively, before shifting the lattice to calculate the GSF curve. Simulation results show that the values of unstable stacking fault energy(γusf), stable stacking fault energy(γsf), and unstable twin fault energy(γutf) of the three elements can change with the preloaded tensile or compressive stress in different directions.The ratio of γsf/γusf, which is related to the energy barrier for full dislocation nucleation, and the ratio of γutf/γusf, which is related to the energy barrier for twinning formation are plotted each as a function of the preloading stress. The results of this study reveal that the stress state can change the energy barrier of defect nucleation in the crystal lattice, and thereby can play an important role in the deformation mechanism of nanocrystalline material.展开更多
为提高元分类器的预测精度,在基于分类器类向量输出的Stacking算法基础上,提出一种基于熵权法的堆叠泛化算法E-Stacking (Stacking based entropy),对于基分类器的输出类别,引入一种熵权法ELFMF (label frequency and mistake frequency...为提高元分类器的预测精度,在基于分类器类向量输出的Stacking算法基础上,提出一种基于熵权法的堆叠泛化算法E-Stacking (Stacking based entropy),对于基分类器的输出类别,引入一种熵权法ELFMF (label frequency and mistake frequency based entropy)。通过考虑基分类器预测结果出现的频率及错误率,以及预测结果在各个类别中的分散度,增强多个元分类器成员之间的差异性,增加堆叠算法的泛化效果。实验结果表明,与传统及各种改进的Stacking算法相比,该算法有效提高了预测精度且更具有适用性。展开更多
基金supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIP) (No. 200983512)Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2013R1A6A3A03063900)the Brain Korea 21
文摘We fabricate and characterize Au nanoparticle-aggregated nanowires by using the nano meniscus-induced colloidal stacking method. The Au nanoparticle solution ejects with guidance of nanopipette/quartz tuning fork-based atomic force microscope in ambient conditions, and the stacking particles form Au nanoparticle-aggregated nanowire while the nozzle retracts from the surface. Their mechanical properties with relatively low elastic modulus are in situ investigated by using the same apparatus.
文摘采用多层感知器模型、随机森林模型为第一层子模型,极端树模型为第二层元模型,建立基于Stacking集成机器学习的波浪预报算法,并引入邻域平均法抑制在拐点处产生的数值震荡。以长江口外海2016年1-9月的风速和中国近海波高数据为数据源,利用机器学习风速与有效波高之间的关系,将2016年10-11月的风速、波高数据用于预报结果的对比分析,预报前45 d R^2拟合优度达到0.97以上,平均误差最大值为0.08 m,平均相对误差最大值为0.05,预报结果与波浪谱模型结果趋势一致,准确度较高;预报结果后15 d误差增长较快,这与训练集数据中寒潮浪占比较少有关。
文摘The influence of temperature on the hydrogen diffusion behavior in X80 pipeline steel during stacking for slow cooling was studied using electrochemical penetration method, the temperature field and the hydrogen diffusion in this pipeline steel during stacking for slow cooling were simulated by ABAQUS finite element method （FEM） software. The results show that in this process there is a reciprocal relationship between the natural logarithm of hydrogen diffusion coefficient and temperature. The cooling rate decreases gradually with the increase of steel plate thickness. The hydrogen content is higher at high temperature （500-400 ℃） than that in low temperature region （300-100 ℃）. The FEM simulation results are consistent with the experimental ones, and the model can be used to predict the hydrogen diffusion behavior in industrial production of X80 pipeline steel.
基金Item Sponsored by Industry-University Cooperation Major Program of Science and Technology Department of Fujian Province of China(2011H6012)Key Program of Science and Technology Department of Fujian Province of China(2011H0001)
文摘The influence of carbon content on the stacking fault energy （SFE） of Fe-20Mn-3Cu twinning-induced plasticity （TWIP） steel was investigated by means of X-ray diffraction peak-shift method and thermodynamic modeling. The experimental result indicated that the stacking fault probability decreases with increasing carbon addition, the SFE increases linearly when the carbon content in mass percent is between 0.23 M and 1.41%. The thermody namic calculation results showed that the SFE varied from 22.40 to 29.64 mJ ~ m 2 when the carbon content in mass percent changes from 0.23 % to 1.41%. The XRD analysis revealed that all steels were fully austenitic before and after deformation, which suggested that TWIP effect is the predominant mechanism during the tensile deformation process of Fe-20Mn-3Cu-XC steels.
基金financially supported by the National Natural Science Foundation of China(No.51601161)the Youth Innovation Fund Project of Xiamen(No.3502Z20206057)the Natural Science Foundation of Fujian Province of China(No.2020J01051)。
文摘Implementation of novelγ/γ'Co-based superalloys with higher strength and improved creep durability is a challenging task for researchers.The lack of atomic-level understanding of plastic deformation behavior has seriously limited the exploration of the full capacity of Co-based alloys.We put forward a comprehensive study of generalized stacking fault energies by first principles to explore the effect of Ni and Al/W on the plastic deformation mechanism ofγ'precipitates in Co-based superalloys.It is found that alloying Ni and adjusting Al/W obviously change the dislocation glide and twinning nucleation in theγ'precipitates by altering the stable fault energies and the unstable fault energy barriers.Excessive addition of either Ni or W deteriorates the strength even the stability of alloys.The ratio of effective planar fault energy(ΔEp)bridges intrinsic energy barriers and various deformation mechanisms of superalloys at elevated temperatures.Except for alloying effects,the grain orientation also significantly governs the operation of the plastic deformation of superalloys.Our theoretical results agree with the available measurements and well capture the observed phenomena in experiments.
基金supported by Australia Research Council Discovery Projects(Grant No.DP130103973)financially supported by the China Scholarship Council(CSC)
文摘Molecular dynamics(MD) simulations are performed to investigate the effects of stress on generalized stacking fault(GSF) energy of three fcc metals(Cu, Al, and Ni). The simulation model is deformed by uniaxial tension or compression in each of [111], [11-2], and [1-10] directions, respectively, before shifting the lattice to calculate the GSF curve. Simulation results show that the values of unstable stacking fault energy(γusf), stable stacking fault energy(γsf), and unstable twin fault energy(γutf) of the three elements can change with the preloaded tensile or compressive stress in different directions.The ratio of γsf/γusf, which is related to the energy barrier for full dislocation nucleation, and the ratio of γutf/γusf, which is related to the energy barrier for twinning formation are plotted each as a function of the preloading stress. The results of this study reveal that the stress state can change the energy barrier of defect nucleation in the crystal lattice, and thereby can play an important role in the deformation mechanism of nanocrystalline material.
文摘为提高元分类器的预测精度,在基于分类器类向量输出的Stacking算法基础上,提出一种基于熵权法的堆叠泛化算法E-Stacking (Stacking based entropy),对于基分类器的输出类别,引入一种熵权法ELFMF (label frequency and mistake frequency based entropy)。通过考虑基分类器预测结果出现的频率及错误率,以及预测结果在各个类别中的分散度,增强多个元分类器成员之间的差异性,增加堆叠算法的泛化效果。实验结果表明,与传统及各种改进的Stacking算法相比,该算法有效提高了预测精度且更具有适用性。
