This paper presents an optimized SRAM that is repairable and dissipates less power. To improve the yield of SRAMs per wafer,redundancy logic and an E-FUSE box are added to the SRAM and an SR SRAM is set up. In order t...This paper presents an optimized SRAM that is repairable and dissipates less power. To improve the yield of SRAMs per wafer,redundancy logic and an E-FUSE box are added to the SRAM and an SR SRAM is set up. In order to reduce power dissipation,power on/off states and isolation logic are introduced into the SR SRAM and an LPSR SRAM is constructed. The optimized LPSR SRAM64K × 32 is used in SoC and the testing method of the LPSR SRAM64K × 32 is also discussed. The SoC design is successfully implemented in the Chartered 90nm CMOS process. The SoC chip occupies 5. 6mm× 5. 6ram of die area and the power dissipation is 1997mW. The test results indicate that LPSR SRAM64K ×32 obtains 17. 301% power savings and the yield of the LPSR SRAM64K × 32s per wafer is improved by 13. 255%.展开更多
In this paper, silt sediment is considered to be Bingham body, which is made up of coarse and fine particles in front of a hydraulic gate. The coarse and fine particles provide friction and shear stress in the course ...In this paper, silt sediment is considered to be Bingham body, which is made up of coarse and fine particles in front of a hydraulic gate. The coarse and fine particles provide friction and shear stress in the course of opening the gate. They constitute together the adhesion force of the sediment. Based on this viewpoint, this paper puts forward a formula for the effect of silt sediment on the lifting force. The formula includes gate weight, down-suction force, sealing rubber friction, plus-weight, water-column pressure, plus-silted-sediment weight and rolling(or sliding)-bearing friction. Finally, the verification results show that the formula has certain reliability and the calculation accuracy can meet the need of practical engineering.展开更多
Given the problem of harmful gas discharge in unsealing coal mining faces, we numerically simulated the process of change of gas flows and movements, We have pointed out that, at the moment of unsealing a closed stope...Given the problem of harmful gas discharge in unsealing coal mining faces, we numerically simulated the process of change of gas flows and movements, We have pointed out that, at the moment of unsealing a closed stope, the gas discharge is naturally divided into two parts, i.e., the discharge of gas in the working face and that in the goaf, because of the difference in the spatial medium. The absolute volume of gas discharged has a tendency to decrease from its initial peak value to a final stable value. The rate of decrease and the time needed to reach a stable discharge are related to the scale of the mining stope. The discharge of gas from the working face is closely related to the amount of air distributed in the air return way. The most important thing in unsealing a stope is to have the initial peak volume of gas discharged well under control. A commonly used method in solving this problem is at first to use a small amount of air and then increasing it gradually. Our study shows that, by extracting gas from the upper corner, we can use a large volume of air at first in order to shorten considerably the discharge time and improve efficiency, thereby making mining, activitv safer.展开更多
Rotating speed is a critical parameter affecting the performance of rotor gyroscopes. Rotor gyroscopes must operate at the rated rotating speed. To shorten the start time of the ball-disk rotor gyroscope, this paper p...Rotating speed is a critical parameter affecting the performance of rotor gyroscopes. Rotor gyroscopes must operate at the rated rotating speed. To shorten the start time of the ball-disk rotor gyroscope, this paper presents a new design of the drive system for a ball-disk rotor gyroscope. The drive system is monitored by a microeontroUer. First, the microcontroller generates a sine pulse width modulation signal to drive the permanent magnet rotor. Second, the position of the rotor is detected according to the back electromotive force in the non-energized coil. Third, a piecewise closed-loop control algorithm is implemented to keep the angular acceleration of the rotor within the safe range automatically during the acceleration process and when running at a constant speed. This control algorithm can avoid rotor stalling due to loss of steps. Experimental result shows that with the help of adaptive quick-start technique, the start time of the device can be shortened by up to 36.6%.展开更多
文摘This paper presents an optimized SRAM that is repairable and dissipates less power. To improve the yield of SRAMs per wafer,redundancy logic and an E-FUSE box are added to the SRAM and an SR SRAM is set up. In order to reduce power dissipation,power on/off states and isolation logic are introduced into the SR SRAM and an LPSR SRAM is constructed. The optimized LPSR SRAM64K × 32 is used in SoC and the testing method of the LPSR SRAM64K × 32 is also discussed. The SoC design is successfully implemented in the Chartered 90nm CMOS process. The SoC chip occupies 5. 6mm× 5. 6ram of die area and the power dissipation is 1997mW. The test results indicate that LPSR SRAM64K ×32 obtains 17. 301% power savings and the yield of the LPSR SRAM64K × 32s per wafer is improved by 13. 255%.
基金Supported by Shandong Province Outstanding Young Scientist Award Fund(No.BS2014SF016)the National Natural Science Foundation of China(No.50979067)+1 种基金Ludong University Doctor Introduction Foundation(No.LY2014026 and No.LY2014028)the Open Research Fund Program of State Key Laboratory of Water Resources and Hydropower Engineering Science(No.2012B104)
文摘In this paper, silt sediment is considered to be Bingham body, which is made up of coarse and fine particles in front of a hydraulic gate. The coarse and fine particles provide friction and shear stress in the course of opening the gate. They constitute together the adhesion force of the sediment. Based on this viewpoint, this paper puts forward a formula for the effect of silt sediment on the lifting force. The formula includes gate weight, down-suction force, sealing rubber friction, plus-weight, water-column pressure, plus-silted-sediment weight and rolling(or sliding)-bearing friction. Finally, the verification results show that the formula has certain reliability and the calculation accuracy can meet the need of practical engineering.
基金Project 50574038 supported by the National Natural Science Foundation of Chinathe Scientific Research Foundation of Liaoning Technical University (No.2004-241)
文摘Given the problem of harmful gas discharge in unsealing coal mining faces, we numerically simulated the process of change of gas flows and movements, We have pointed out that, at the moment of unsealing a closed stope, the gas discharge is naturally divided into two parts, i.e., the discharge of gas in the working face and that in the goaf, because of the difference in the spatial medium. The absolute volume of gas discharged has a tendency to decrease from its initial peak value to a final stable value. The rate of decrease and the time needed to reach a stable discharge are related to the scale of the mining stope. The discharge of gas from the working face is closely related to the amount of air distributed in the air return way. The most important thing in unsealing a stope is to have the initial peak volume of gas discharged well under control. A commonly used method in solving this problem is at first to use a small amount of air and then increasing it gradually. Our study shows that, by extracting gas from the upper corner, we can use a large volume of air at first in order to shorten considerably the discharge time and improve efficiency, thereby making mining, activitv safer.
基金Project supported by the National Basic Research Program of China （No. 2012CB934104）, the National Natural Science Foundation of China （No. 61474034）, the Natural Science Foundation of Heilongjiang Province of China （No. F201418）, and the Fundamental Research Funds for the Central Universities, China （Nos. HIT.NSRIF. 2014040 and HIT.NSRIF.2013040）
文摘Rotating speed is a critical parameter affecting the performance of rotor gyroscopes. Rotor gyroscopes must operate at the rated rotating speed. To shorten the start time of the ball-disk rotor gyroscope, this paper presents a new design of the drive system for a ball-disk rotor gyroscope. The drive system is monitored by a microeontroUer. First, the microcontroller generates a sine pulse width modulation signal to drive the permanent magnet rotor. Second, the position of the rotor is detected according to the back electromotive force in the non-energized coil. Third, a piecewise closed-loop control algorithm is implemented to keep the angular acceleration of the rotor within the safe range automatically during the acceleration process and when running at a constant speed. This control algorithm can avoid rotor stalling due to loss of steps. Experimental result shows that with the help of adaptive quick-start technique, the start time of the device can be shortened by up to 36.6%.
