Let Gn（C） be the sandwich semigroup of generalized circulant Boolean matrices with the sandwich matrix C and Gc（Jr~） the set of all primitive matrices in Gn（C）. In this paper, some necessary and sufficient condi...Let Gn（C） be the sandwich semigroup of generalized circulant Boolean matrices with the sandwich matrix C and Gc（Jr~） the set of all primitive matrices in Gn（C）. In this paper, some necessary and sufficient conditions for A in the semigroup Gn（C） to be primitive are given. We also show that Gc（Jn） is a subsemigroup of Gn（C）.展开更多
A third-generation horseradish peroxidase (HRP) biosensor has been developed by adsorbing HRP on multi-wall carbon nanotube (MWNTs) monolayer modified gold electrode surface. The assembly process was investigated by...A third-generation horseradish peroxidase (HRP) biosensor has been developed by adsorbing HRP on multi-wall carbon nanotube (MWNTs) monolayer modified gold electrode surface. The assembly process was investigated by electrochemical and spectroscopic techniques. Results showed that the immobilized HRP exhibited direct electrochemical behavior toward the reduction of H2O2. The resulting biosensor shows a fast amperometric response (<2 s) to H2O2. The linear response range was from 5.0×10-7～1.0×10-5 mol/L with a detection limit of 1.0×10-7mol/L. Moreover, the biosensor has a good reproducibility, and long-term stability.展开更多
The rotor initial unbalance of an aeroengine gas generator of turboshaft engine seriously affects rotor assembly process.To reasonably optimize rotor assembly process,the effect analyses of rotor initial unbalance of ...The rotor initial unbalance of an aeroengine gas generator of turboshaft engine seriously affects rotor assembly process.To reasonably optimize rotor assembly process,the effect analyses of rotor initial unbalance of single disc and combined discs on rotor dynamic characteristics are firstly implemented in respect of the dispersity of rotor initial unbalance.It is found that the most important factors contributing to rotor vibration are the unbalances of the first stage compressor disc and the second stage turbine disc.However,reducing the mass of two discs conflicts with the control of the whole gas generator rotor balance resulting from the unbalance increase of single components.Thus,we further analyze the key control factors of affecting rotor initial unbalance,and give the strict control measures of centrifugal impeller runout in the assembly process by adjusting the angle of central tie rod axis.The purpose of this measures to make the assembly process simpler and more effective for timely controlling rotor initial unbalance.The efforts of this study validate that the proposed method is workable for the rotor tightened by a central tie rod and possesses the significant meaning of practical application in engineering.展开更多
The status of material delivery of an automobile general assembly line is analyzed, and the technique to achieve the real-time tracking of assembly status information is proposed based on RFID（ Radio Frequency Identi...The status of material delivery of an automobile general assembly line is analyzed, and the technique to achieve the real-time tracking of assembly status information is proposed based on RFID（ Radio Frequency Identification）. Thus the consumption of line-side buffer is obtained dynamically, then the type and quantity of needed material are fed back to the subsystem of material handling; the algorithm for determining the best time departure time of delivery driver based on minimizing of total time penalty function is proposed. This approach makes the material amount of a single delivery trip maximized and improves the efficiency of delivery drivers significantly in the case of does not affect the assembly line normal throughput. Additionally, although this dynamic material handling method is developed for the automobile assembly plant, it should be pointed out that this method is also applicable to other mixed model assembly plants such as electronics, semiconductor and aerospace industry.展开更多
基金Supported by the National Natural Science Foundation of China(11071272,11101087)the Postdoctoral Science Foundation of China(2013M531785)+1 种基金the Natural Science Foundation of Fujian Province(2013J05006)the Foundation of Fuzhou University(2012-XQ-30)
文摘Let Gn（C） be the sandwich semigroup of generalized circulant Boolean matrices with the sandwich matrix C and Gc（Jr~） the set of all primitive matrices in Gn（C）. In this paper, some necessary and sufficient conditions for A in the semigroup Gn（C） to be primitive are given. We also show that Gc（Jn） is a subsemigroup of Gn（C）.
文摘A third-generation horseradish peroxidase (HRP) biosensor has been developed by adsorbing HRP on multi-wall carbon nanotube (MWNTs) monolayer modified gold electrode surface. The assembly process was investigated by electrochemical and spectroscopic techniques. Results showed that the immobilized HRP exhibited direct electrochemical behavior toward the reduction of H2O2. The resulting biosensor shows a fast amperometric response (<2 s) to H2O2. The linear response range was from 5.0×10-7～1.0×10-5 mol/L with a detection limit of 1.0×10-7mol/L. Moreover, the biosensor has a good reproducibility, and long-term stability.
文摘The rotor initial unbalance of an aeroengine gas generator of turboshaft engine seriously affects rotor assembly process.To reasonably optimize rotor assembly process,the effect analyses of rotor initial unbalance of single disc and combined discs on rotor dynamic characteristics are firstly implemented in respect of the dispersity of rotor initial unbalance.It is found that the most important factors contributing to rotor vibration are the unbalances of the first stage compressor disc and the second stage turbine disc.However,reducing the mass of two discs conflicts with the control of the whole gas generator rotor balance resulting from the unbalance increase of single components.Thus,we further analyze the key control factors of affecting rotor initial unbalance,and give the strict control measures of centrifugal impeller runout in the assembly process by adjusting the angle of central tie rod axis.The purpose of this measures to make the assembly process simpler and more effective for timely controlling rotor initial unbalance.The efforts of this study validate that the proposed method is workable for the rotor tightened by a central tie rod and possesses the significant meaning of practical application in engineering.
文摘The status of material delivery of an automobile general assembly line is analyzed, and the technique to achieve the real-time tracking of assembly status information is proposed based on RFID（ Radio Frequency Identification）. Thus the consumption of line-side buffer is obtained dynamically, then the type and quantity of needed material are fed back to the subsystem of material handling; the algorithm for determining the best time departure time of delivery driver based on minimizing of total time penalty function is proposed. This approach makes the material amount of a single delivery trip maximized and improves the efficiency of delivery drivers significantly in the case of does not affect the assembly line normal throughput. Additionally, although this dynamic material handling method is developed for the automobile assembly plant, it should be pointed out that this method is also applicable to other mixed model assembly plants such as electronics, semiconductor and aerospace industry.
