Synthetic aperture radar (SAR) is theoretically based on uniform rectilinear motion. But in real situations, the flight cannot be kept in a uniform rectilinear motion due to many factors. Therefore, the motion compens...Synthetic aperture radar (SAR) is theoretically based on uniform rectilinear motion. But in real situations, the flight cannot be kept in a uniform rectilinear motion due to many factors. Therefore, the motion compensation is needed to achieve the high-resolution image. This paper proposes an improved motion information sensor (MIS)-based on global navigation statellite system (GNSS) and strapdown inertial navigation system (SINS) for SAR motion compensation. MIS can provide the long-term absolute accuracy, and the short-term high relative accuracy during SAR imaging. Many issues related to MIS, such as system design, error models and navigation algorithms, are stressed. Experimental results show that MIS can provide accurate navigation information (position, velocity and attitude) to meet the requirements of SAR motion compensation. Especially, MIS is suitable for the case: the accuracy of airplane master inertial navigation system is too low or not configured.展开更多
For multiple grid-connected inverters with active filter function,it makes sense to regulate every unit to output maximum active power from photovoltaic arrays,as well as eliminate the harmonic due to the non-linear l...For multiple grid-connected inverters with active filter function,it makes sense to regulate every unit to output maximum active power from photovoltaic arrays,as well as eliminate the harmonic due to the non-linear loads connected to the electric networks.Naturally,a centralized control coordination strategy was proposed for the purpose of high facility utilization,good harmonic compensation ability and unwanted overcompensation condition.Based on a vector decoupling control scheme and generalized instantaneous reactive power theory,the solution was to allocate the harmonic eliminating task for every inverter according to the instantaneous power margin of each.The grid current always keeps sinusoidal in spite of non-linear load change and output active power change for any inverter.The simulation results validate the efficacy of the proposed coordination strategy.展开更多
The new dust removal technical route using the carbon-granular bed filter, packed of carbon particles with appropriate grade derive from an online-process vibration sieve, to replace the traditional baggy filter had b...The new dust removal technical route using the carbon-granular bed filter, packed of carbon particles with appropriate grade derive from an online-process vibration sieve, to replace the traditional baggy filter had been developed successfully for capturing the micro-carbon dusts produced from pulverization of petroleum coke, and the green close loop of carbon materials is thus completed in the combined pulverizing and classifying system and pulverized carbon dust removal process. The high dust removal efficiency greater than 99%, low outlet dust concentration less than 100mg·m-3, low pressure drop through dust filtration chamber less than 980Pa, simple and easy design, and flexible and stable operation were achieved also with the carbon-granular bed filter in both bench and industrial scale operations.展开更多
Distribution systems operators are often confronted with declined power quality, which can cause substantial economical losses. The problem analyzed in paper concerns thyristor controlled direct current motor used for...Distribution systems operators are often confronted with declined power quality, which can cause substantial economical losses. The problem analyzed in paper concerns thyristor controlled direct current motor used for ski-lift in ski resort as a source of disturbances with negative impact on sensitive electric equipment, which is then unable to operate correctly. To solve mentioned problems, series of measurements of voltage quality parameters were carried out according to the respective valid standards. Crucial power quality parameters necessary for parallel power active filter design were then analyzed. Power active filter compensates power factor and filters characteristic current harmonics. After power active filter was put into operation, power quality problems were eliminated. Payback period is estimated up to four years.展开更多
Since novel optoelectronic devices based on the peculiar behaviors of the tunneling probability, e.g., resonant tunneling devices (RTD) and band-pass filter, are steadily proposed, the analytic transfer matrix (ATM) m...Since novel optoelectronic devices based on the peculiar behaviors of the tunneling probability, e.g., resonant tunneling devices (RTD) and band-pass filter, are steadily proposed, the analytic transfer matrix (ATM) method is extended to study these devices. For several examples, we explore the effect of the scattered subwaves on tunneling; it is shown that the resonant or band-pass structures in tunneling probability are determined by the phase shift results from the scattered subwaves.展开更多
文摘Synthetic aperture radar (SAR) is theoretically based on uniform rectilinear motion. But in real situations, the flight cannot be kept in a uniform rectilinear motion due to many factors. Therefore, the motion compensation is needed to achieve the high-resolution image. This paper proposes an improved motion information sensor (MIS)-based on global navigation statellite system (GNSS) and strapdown inertial navigation system (SINS) for SAR motion compensation. MIS can provide the long-term absolute accuracy, and the short-term high relative accuracy during SAR imaging. Many issues related to MIS, such as system design, error models and navigation algorithms, are stressed. Experimental results show that MIS can provide accurate navigation information (position, velocity and attitude) to meet the requirements of SAR motion compensation. Especially, MIS is suitable for the case: the accuracy of airplane master inertial navigation system is too low or not configured.
基金Project(51107111)supported by the National Natural Science Foundation of China
文摘For multiple grid-connected inverters with active filter function,it makes sense to regulate every unit to output maximum active power from photovoltaic arrays,as well as eliminate the harmonic due to the non-linear loads connected to the electric networks.Naturally,a centralized control coordination strategy was proposed for the purpose of high facility utilization,good harmonic compensation ability and unwanted overcompensation condition.Based on a vector decoupling control scheme and generalized instantaneous reactive power theory,the solution was to allocate the harmonic eliminating task for every inverter according to the instantaneous power margin of each.The grid current always keeps sinusoidal in spite of non-linear load change and output active power change for any inverter.The simulation results validate the efficacy of the proposed coordination strategy.
基金the Fujian Provincial Science and Technology Council Grant (No. 2001H043).
文摘The new dust removal technical route using the carbon-granular bed filter, packed of carbon particles with appropriate grade derive from an online-process vibration sieve, to replace the traditional baggy filter had been developed successfully for capturing the micro-carbon dusts produced from pulverization of petroleum coke, and the green close loop of carbon materials is thus completed in the combined pulverizing and classifying system and pulverized carbon dust removal process. The high dust removal efficiency greater than 99%, low outlet dust concentration less than 100mg·m-3, low pressure drop through dust filtration chamber less than 980Pa, simple and easy design, and flexible and stable operation were achieved also with the carbon-granular bed filter in both bench and industrial scale operations.
文摘Distribution systems operators are often confronted with declined power quality, which can cause substantial economical losses. The problem analyzed in paper concerns thyristor controlled direct current motor used for ski-lift in ski resort as a source of disturbances with negative impact on sensitive electric equipment, which is then unable to operate correctly. To solve mentioned problems, series of measurements of voltage quality parameters were carried out according to the respective valid standards. Crucial power quality parameters necessary for parallel power active filter design were then analyzed. Power active filter compensates power factor and filters characteristic current harmonics. After power active filter was put into operation, power quality problems were eliminated. Payback period is estimated up to four years.
基金supported by the State Key Laboratory of Advanced Optical Communication Systems and Networks (Grant No. 2008SH05)
文摘Since novel optoelectronic devices based on the peculiar behaviors of the tunneling probability, e.g., resonant tunneling devices (RTD) and band-pass filter, are steadily proposed, the analytic transfer matrix (ATM) method is extended to study these devices. For several examples, we explore the effect of the scattered subwaves on tunneling; it is shown that the resonant or band-pass structures in tunneling probability are determined by the phase shift results from the scattered subwaves.
