A multivariate method for fault diagnosis and process monitoring is proposed. This technique is based on a statistical pattern(SP) framework integrated with a self-organizing map(SOM). An SP-based SOM is used as a cla...A multivariate method for fault diagnosis and process monitoring is proposed. This technique is based on a statistical pattern(SP) framework integrated with a self-organizing map(SOM). An SP-based SOM is used as a classifier to distinguish various states on the output map, which can visually monitor abnormal states. A case study of the Tennessee Eastman(TE) process is presented to demonstrate the fault diagnosis and process monitoring performance of the proposed method. Results show that the SP-based SOM method is a visual tool for real-time monitoring and fault diagnosis that can be used in complex chemical processes.Compared with other SOM-based methods, the proposed method can more efficiently monitor and diagnose faults.展开更多
Circular aperture antenna recently has been regarded as a nature source to generate high power radio orbital angular momentum (OAM) in millimeter (mm) wave; however, the radiation pattern was not investigated. Theoret...Circular aperture antenna recently has been regarded as a nature source to generate high power radio orbital angular momentum (OAM) in millimeter (mm) wave; however, the radiation pattern was not investigated. Theoretical derivation of radiation pattern of circular aperture OAM antenna is conducted to evaluate the performance. Extensive simulations verify the validity of the theoretical result. Furthermore, performance of such antenna excited by orthogonal TE and TM modes is compared, which shows the potential application for TEgl mode to create pure OAM g-1 mode in a practical system, providing guidance for generation of twisted radio waves in mm-wave bands.展开更多
2022年5月,欧亚大陆中高纬度地区出现了“三极子”型的异常表面气温(Surface air temperature,SAT),东欧和东北亚偏冷,欧亚大陆中北部偏暖,是2000年以来5月最明显的一次气温异常。基于多种资料和方法,本文探讨了此次“三极子”型异常气...2022年5月,欧亚大陆中高纬度地区出现了“三极子”型的异常表面气温(Surface air temperature,SAT),东欧和东北亚偏冷,欧亚大陆中北部偏暖,是2000年以来5月最明显的一次气温异常。基于多种资料和方法,本文探讨了此次“三极子”型异常气温的特点和成因。结果表明:“三极子”型异常SAT在5月15—27日期间最显著,与“三极子”型的异常大气环流密切相关,偏暖(冷)处受到了异常高(低)压和异常偏南(北)风的影响,欧亚大陆中北部(东欧)还受到了异常下沉(上升)运动和净热通量正(负)异常的影响,东北亚较弱的异常环流可能是该处SAT异常较弱的原因。比较不同物理过程对三极子各区域SAT异常的贡献,发现异常温度平流(异常经向风对气候态温度的平流)在“三极子”型异常SAT的形成中贡献最大,贡献率分别为40.5%、18.7%和17.7%。“三极子”型异常环流与两支波列有关。里海以北和中纬度北大西洋东部分别在5月9—10日和15—17日期间有与低层辐合异常和高层辐散异常相关的异常上升运动,导致降水异常偏多。线性斜压模式结果证明,降水导致的潜热释放在对流层形成的异常热源可以激发出欧亚大陆上的“三极子”型环流。展开更多
基金Project(2013CB733605)supported by the National Basic Research Program of ChinaProject(21176073)supported by the National Natural Science Foundation of ChinaProject supported by the Fundamental Research Funds for the Central Universities,China
文摘A multivariate method for fault diagnosis and process monitoring is proposed. This technique is based on a statistical pattern(SP) framework integrated with a self-organizing map(SOM). An SP-based SOM is used as a classifier to distinguish various states on the output map, which can visually monitor abnormal states. A case study of the Tennessee Eastman(TE) process is presented to demonstrate the fault diagnosis and process monitoring performance of the proposed method. Results show that the SP-based SOM method is a visual tool for real-time monitoring and fault diagnosis that can be used in complex chemical processes.Compared with other SOM-based methods, the proposed method can more efficiently monitor and diagnose faults.
文摘Circular aperture antenna recently has been regarded as a nature source to generate high power radio orbital angular momentum (OAM) in millimeter (mm) wave; however, the radiation pattern was not investigated. Theoretical derivation of radiation pattern of circular aperture OAM antenna is conducted to evaluate the performance. Extensive simulations verify the validity of the theoretical result. Furthermore, performance of such antenna excited by orthogonal TE and TM modes is compared, which shows the potential application for TEgl mode to create pure OAM g-1 mode in a practical system, providing guidance for generation of twisted radio waves in mm-wave bands.
文摘2022年5月,欧亚大陆中高纬度地区出现了“三极子”型的异常表面气温(Surface air temperature,SAT),东欧和东北亚偏冷,欧亚大陆中北部偏暖,是2000年以来5月最明显的一次气温异常。基于多种资料和方法,本文探讨了此次“三极子”型异常气温的特点和成因。结果表明:“三极子”型异常SAT在5月15—27日期间最显著,与“三极子”型的异常大气环流密切相关,偏暖(冷)处受到了异常高(低)压和异常偏南(北)风的影响,欧亚大陆中北部(东欧)还受到了异常下沉(上升)运动和净热通量正(负)异常的影响,东北亚较弱的异常环流可能是该处SAT异常较弱的原因。比较不同物理过程对三极子各区域SAT异常的贡献,发现异常温度平流(异常经向风对气候态温度的平流)在“三极子”型异常SAT的形成中贡献最大,贡献率分别为40.5%、18.7%和17.7%。“三极子”型异常环流与两支波列有关。里海以北和中纬度北大西洋东部分别在5月9—10日和15—17日期间有与低层辐合异常和高层辐散异常相关的异常上升运动,导致降水异常偏多。线性斜压模式结果证明,降水导致的潜热释放在对流层形成的异常热源可以激发出欧亚大陆上的“三极子”型环流。
