1.Introduction Al-Zn-Mg-Cu alloy is a typical age-hardening aluminum alloy,its strength and toughness are significantly influenced by precipita-tion behavior.The nucleation mechanisms of precipitates in this alloy are...1.Introduction Al-Zn-Mg-Cu alloy is a typical age-hardening aluminum alloy,its strength and toughness are significantly influenced by precipita-tion behavior.The nucleation mechanisms of precipitates in this alloy are generally categorized into homogeneous and heterogeneous nucleation.Homogeneous nucleation relies on structural and energy fluctuations within the solution to generate the driving force necessary for direct nucleation.展开更多
Anti-structured defects bridge atom migration among heterogeneous sublattices facilitating diffusion but could also result in the collapse of ordered structure.Component distribution Ni（75）AlxV（25-x） alloys are in...Anti-structured defects bridge atom migration among heterogeneous sublattices facilitating diffusion but could also result in the collapse of ordered structure.Component distribution Ni（75）AlxV（25-x） alloys are investigated using a microscopic phase field model to illuminate relations between anti-structured defects and composition,precipitate order,precipitate type,and phase stability.The Ni（75）AlxV（25-x） alloys undergo single Ni3V（stage Ⅰ）,dual Ni3Al and Ni3V（stage Ⅱ with Ni3V prior;and stage Ⅲ with Ni3Al prior）,and single Ni3Al（stage Ⅳ） with enhanced aluminum level.For Ni3V phase,anti-structured defects（V（Ni1）,Niy,except V（Ni2）） and substitution defects（Al（Ni1）,Al（Ni2）,Alv） exhibit a positive correlation to aluminum in stage I,the positive trend becomes to negative correlation or smooth during stage Ⅱ.For Ni3 Al phase,anti-structured defects（Al（Ni）,Ni（Al）） and substitution defects（V（Ni）,V（Al）） have a positive correlation to aluminum in stage Ⅱ,but Ni（Al） goes down since stage Ⅲ and lasts to stage Ⅳ.V（Ni） and V（Al） fluctuate when Ni3Al precipitates prior,but go down drastically in stageⅣ.Precipitate type conversion of single Ni3V/dual（Ni3V＋Ni3Al） affects Ni3V defects,while dual（Ni3V＋Ni3Al）/single Ni3 Al has little effect on Ni3Al defects.Precipitate order swap occurred in the dual phase region affects on Ni3Al defects but not on Ni3V.展开更多
Abnormal conditions are hazardous in complex process systems, and the aim of condition recognition is to detect abnormal conditions and thus avoid severe accidents. The relationship of linkage fluctuation between moni...Abnormal conditions are hazardous in complex process systems, and the aim of condition recognition is to detect abnormal conditions and thus avoid severe accidents. The relationship of linkage fluctuation between monitoring variables can characterize the operation state of the system. In this study,we present a straightforward and fast computational method, the multivariable linkage coarse graining(MLCG) algorithm, which converts the linkage fluctuation relationship of multivariate time series into a directed and weighted complex network. The directed and weighted complex network thus constructed inherits several properties of the series in its structure. Thereby, periodic series convert into regular networks, and random series convert into random networks. Moreover, chaotic time series convert into scale-free networks. It demonstrates that the MLCG algorithm permits us to distinguish, identify, and describe in detail various time series. Finally, we apply the MLCG algorithm to practical observations series, the monitoring time series from a compressor unit, and identify its dynamic characteristics. Empirical results demonstrate that the MLCG algorithm is suitable for analyzing the multivariable linkage fluctuation relationship in complex electromechanical system. This method can be used to detect specific or abnormal operation condition, which is relevant to condition identification and information quality control of complex electromechanical system in the process industry.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.U21A20130 and 52475357).
文摘1.Introduction Al-Zn-Mg-Cu alloy is a typical age-hardening aluminum alloy,its strength and toughness are significantly influenced by precipita-tion behavior.The nucleation mechanisms of precipitates in this alloy are generally categorized into homogeneous and heterogeneous nucleation.Homogeneous nucleation relies on structural and energy fluctuations within the solution to generate the driving force necessary for direct nucleation.
基金Project supported by the Natural Science Basic Research Plan in Shaanxi Province of China(Grant No.2016JQ5014)the Fundamental Research Funds for the Central Universities,China(Grant No.3102014JCQ01024)+2 种基金the Research Fund of the State Key Laboratory of Solidification Processing(NWPU),China(Grant No.114-QP-2014)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20136102120021)the National Natural Science Foundation of China(Grant Nos.51474716 and 51475378)
文摘Anti-structured defects bridge atom migration among heterogeneous sublattices facilitating diffusion but could also result in the collapse of ordered structure.Component distribution Ni（75）AlxV（25-x） alloys are investigated using a microscopic phase field model to illuminate relations between anti-structured defects and composition,precipitate order,precipitate type,and phase stability.The Ni（75）AlxV（25-x） alloys undergo single Ni3V（stage Ⅰ）,dual Ni3Al and Ni3V（stage Ⅱ with Ni3V prior;and stage Ⅲ with Ni3Al prior）,and single Ni3Al（stage Ⅳ） with enhanced aluminum level.For Ni3V phase,anti-structured defects（V（Ni1）,Niy,except V（Ni2）） and substitution defects（Al（Ni1）,Al（Ni2）,Alv） exhibit a positive correlation to aluminum in stage I,the positive trend becomes to negative correlation or smooth during stage Ⅱ.For Ni3 Al phase,anti-structured defects（Al（Ni）,Ni（Al）） and substitution defects（V（Ni）,V（Al）） have a positive correlation to aluminum in stage Ⅱ,but Ni（Al） goes down since stage Ⅲ and lasts to stage Ⅳ.V（Ni） and V（Al） fluctuate when Ni3Al precipitates prior,but go down drastically in stageⅣ.Precipitate type conversion of single Ni3V/dual（Ni3V＋Ni3Al） affects Ni3V defects,while dual（Ni3V＋Ni3Al）/single Ni3 Al has little effect on Ni3Al defects.Precipitate order swap occurred in the dual phase region affects on Ni3Al defects but not on Ni3V.
基金supported by the National Natural Science Foundation of China(Grant No.51375375)
文摘Abnormal conditions are hazardous in complex process systems, and the aim of condition recognition is to detect abnormal conditions and thus avoid severe accidents. The relationship of linkage fluctuation between monitoring variables can characterize the operation state of the system. In this study,we present a straightforward and fast computational method, the multivariable linkage coarse graining(MLCG) algorithm, which converts the linkage fluctuation relationship of multivariate time series into a directed and weighted complex network. The directed and weighted complex network thus constructed inherits several properties of the series in its structure. Thereby, periodic series convert into regular networks, and random series convert into random networks. Moreover, chaotic time series convert into scale-free networks. It demonstrates that the MLCG algorithm permits us to distinguish, identify, and describe in detail various time series. Finally, we apply the MLCG algorithm to practical observations series, the monitoring time series from a compressor unit, and identify its dynamic characteristics. Empirical results demonstrate that the MLCG algorithm is suitable for analyzing the multivariable linkage fluctuation relationship in complex electromechanical system. This method can be used to detect specific or abnormal operation condition, which is relevant to condition identification and information quality control of complex electromechanical system in the process industry.
