Semiconductor fabrication is a manufacturing sequence with hundreds of sophisticated unit operations and it is always challenged by strategy development for ensuring the yield of defect-free products.In this paper,an ...Semiconductor fabrication is a manufacturing sequence with hundreds of sophisticated unit operations and it is always challenged by strategy development for ensuring the yield of defect-free products.In this paper,an advanced control strategy through integrating product and process control is established.The proposed multiscale scheme contains three layers for coordinated equipment control,process control and product quality control.In the upper layer,online control performance assessment is applied to reduce the quality variation and maximize the overall product performance （OPP）.It serves as supervisory control to update the recipe of the process controller in the middle layer.The process controller is designed as an exponentially weighted moving average （EWMA） run-to-run controller to reject disturbances,such as process shift,drift and tool worn out,that are exerted to the op-eration.The equipment in the process is individually controlled to maintain its optimal operational status and maximize the overall equipment effectiveness （OEE）,based on the set point given by the process controller.The ef-ficacy of the proposed integrated control scheme is demonstrated through case studies,where both the OPP （for product） and the OEE （for equipment） are enhanced.展开更多
A wet impact crusher was used to breakdown waste printed circuit boards （PCB＇s） in a water medium. The relationship between the yield of crushed product and the operating parameters was established. The crushing me...A wet impact crusher was used to breakdown waste printed circuit boards （PCB＇s） in a water medium. The relationship between the yield of crushed product and the operating parameters was established. The crushing mechanism was analyzed and the effects of hammerhead style, rotation speed, and inlet water volume on particle size distribution were investigated. The results show that the highest yield of -1 ＋ 0.75 mm sized product was obtained with an inlet water volume flow rate of 5.97 m3/h and a smooth hammerhead turning at 1246.15 r/rain. Cumulative undersize-product yield curves were fitted to a nonlinear function： the fitting correlation coefficient was greater than 0.998. These research results provide a theoretical basis for the highly effective wet crushing of PCB＇s.展开更多
Biomass in the form of nutshell, hay of catkin, wheat straw and linseed residue in particles have been pyrolyzed in laboratory scale fixed bed reactor which yielded liquid oil, solid char and gas. The variation of oil...Biomass in the form of nutshell, hay of catkin, wheat straw and linseed residue in particles have been pyrolyzed in laboratory scale fixed bed reactor which yielded liquid oil, solid char and gas. The variation of oil yield for different biomass feedstock with reactor bed temperature and feed size is presented in this paper. A maximum liquid yield of 55 wt% of dry feedstock is obtained at an optimum temperature of 500℃ for a feed size of 300-600μm with a running time of 55 min for nutshell as the feedstock while the minimum liquid oil yield is found to be 30 wt% of feedstock at an optimum temperature of 400℃ for a feed size of 2.36 mm with a running time of 65 min for linseed residue as the feedstock. A comparison on the product yields is highlighted in this study. The pyrolysis liquid products are characterized and compared for some of the fuel properties like HHV （higher heating value）, viscosity, density and specific gravity.展开更多
Along with the vigorous development of the markel economy, the transactions in the market are also increasingly frequent. In all kinds of market transactions, there are more or less inIbrmation asynunetry phenomena. A...Along with the vigorous development of the markel economy, the transactions in the market are also increasingly frequent. In all kinds of market transactions, there are more or less inIbrmation asynunetry phenomena. Asynmaetric information makes supply chain unable to give a real reaction to the relationship between market supply and demand, and the personnel in the channels of supply chain are unable to make the optimal pricing, so that the overall profits are affected. Therefore, asymmetric information should be controlled within the normal range, for the purpose of ensuring the normal operation and healthy development of the market transactions.展开更多
文摘Semiconductor fabrication is a manufacturing sequence with hundreds of sophisticated unit operations and it is always challenged by strategy development for ensuring the yield of defect-free products.In this paper,an advanced control strategy through integrating product and process control is established.The proposed multiscale scheme contains three layers for coordinated equipment control,process control and product quality control.In the upper layer,online control performance assessment is applied to reduce the quality variation and maximize the overall product performance （OPP）.It serves as supervisory control to update the recipe of the process controller in the middle layer.The process controller is designed as an exponentially weighted moving average （EWMA） run-to-run controller to reject disturbances,such as process shift,drift and tool worn out,that are exerted to the op-eration.The equipment in the process is individually controlled to maintain its optimal operational status and maximize the overall equipment effectiveness （OEE）,based on the set point given by the process controller.The ef-ficacy of the proposed integrated control scheme is demonstrated through case studies,where both the OPP （for product） and the OEE （for equipment） are enhanced.
基金financially supported by the National Natural Science Foundation of China for Creative Research Groups Science Foundation (No.50921002)the National Natural Science Foundation of China (Nos.50574094 and 51074156)+2 种基金the China Postdoctoral Science (No.20090461153)the China Postdoctoral Science Foundation funded projects in particular (No.201003607)the Key Laboratory for Solid Waste Management and Environment Safety Open Foundation (No.swmes-2010-08)
文摘A wet impact crusher was used to breakdown waste printed circuit boards （PCB＇s） in a water medium. The relationship between the yield of crushed product and the operating parameters was established. The crushing mechanism was analyzed and the effects of hammerhead style, rotation speed, and inlet water volume on particle size distribution were investigated. The results show that the highest yield of -1 ＋ 0.75 mm sized product was obtained with an inlet water volume flow rate of 5.97 m3/h and a smooth hammerhead turning at 1246.15 r/rain. Cumulative undersize-product yield curves were fitted to a nonlinear function： the fitting correlation coefficient was greater than 0.998. These research results provide a theoretical basis for the highly effective wet crushing of PCB＇s.
文摘Biomass in the form of nutshell, hay of catkin, wheat straw and linseed residue in particles have been pyrolyzed in laboratory scale fixed bed reactor which yielded liquid oil, solid char and gas. The variation of oil yield for different biomass feedstock with reactor bed temperature and feed size is presented in this paper. A maximum liquid yield of 55 wt% of dry feedstock is obtained at an optimum temperature of 500℃ for a feed size of 300-600μm with a running time of 55 min for nutshell as the feedstock while the minimum liquid oil yield is found to be 30 wt% of feedstock at an optimum temperature of 400℃ for a feed size of 2.36 mm with a running time of 65 min for linseed residue as the feedstock. A comparison on the product yields is highlighted in this study. The pyrolysis liquid products are characterized and compared for some of the fuel properties like HHV （higher heating value）, viscosity, density and specific gravity.
文摘Along with the vigorous development of the markel economy, the transactions in the market are also increasingly frequent. In all kinds of market transactions, there are more or less inIbrmation asynunetry phenomena. Asynmaetric information makes supply chain unable to give a real reaction to the relationship between market supply and demand, and the personnel in the channels of supply chain are unable to make the optimal pricing, so that the overall profits are affected. Therefore, asymmetric information should be controlled within the normal range, for the purpose of ensuring the normal operation and healthy development of the market transactions.
