Based on the theory of air supply jet, the conception and theory of the air quality and the drain contamination efficiency, the results achieved by comparing the circular cross section wall jet with the plane wall jet...Based on the theory of air supply jet, the conception and theory of the air quality and the drain contamination efficiency, the results achieved by comparing the circular cross section wall jet with the plane wall jet were following: firstly, within the limitation of the ventilation distance at the tunnel heading in a coal mine, there were a better air quality and a higher efficiency of drain contamination with application of the plane wall jet ventilation. Secondly, there was a advantage to improve the air quality of the workers breathing area with mounting the air supply outlet on the top but not on the side of the tunnel heading.展开更多
A digital predistorted class-F power amplifier （PA） using Cree GaN HEMT CGH40010 operating at 2. 12 GHz is presented to obtain high efficiency and excellent linearity for wideband code-division multiple access （ WC...A digital predistorted class-F power amplifier （PA） using Cree GaN HEMT CGH40010 operating at 2. 12 GHz is presented to obtain high efficiency and excellent linearity for wideband code-division multiple access （ WCDMA ） applications. Measurement results with the continuous wave （CW） signals indicate that the designed class-F PA achieves a peak power-added efficiency （PAE） of 75. 2% with an output power of 39.4 dBm. The adjacent channel power ratio （ACPR） of the designed PA after digital predistortion （DPD） decreases from -28. 3 and -27. 5 dBc to -51.9 and -54. 0 dBc, respectively, for a 4-carrier 20 MHz WCDMA signal with 7. 1 dB peak to average power ratio （PAPR）. The drain efficiency （DE） of the PA is 37. 8% at an average output power of 33. 3 dBm. The designed power amplifier can be aoolied in the WCDMA system.展开更多
文摘Based on the theory of air supply jet, the conception and theory of the air quality and the drain contamination efficiency, the results achieved by comparing the circular cross section wall jet with the plane wall jet were following: firstly, within the limitation of the ventilation distance at the tunnel heading in a coal mine, there were a better air quality and a higher efficiency of drain contamination with application of the plane wall jet ventilation. Secondly, there was a advantage to improve the air quality of the workers breathing area with mounting the air supply outlet on the top but not on the side of the tunnel heading.
基金The National Natural Science Foundation of China(No.60702163)the National Science and Technology Major Project(No.2010ZX03007-002-01,2011ZX03004-003)
文摘A digital predistorted class-F power amplifier （PA） using Cree GaN HEMT CGH40010 operating at 2. 12 GHz is presented to obtain high efficiency and excellent linearity for wideband code-division multiple access （ WCDMA ） applications. Measurement results with the continuous wave （CW） signals indicate that the designed class-F PA achieves a peak power-added efficiency （PAE） of 75. 2% with an output power of 39.4 dBm. The adjacent channel power ratio （ACPR） of the designed PA after digital predistortion （DPD） decreases from -28. 3 and -27. 5 dBc to -51.9 and -54. 0 dBc, respectively, for a 4-carrier 20 MHz WCDMA signal with 7. 1 dB peak to average power ratio （PAPR）. The drain efficiency （DE） of the PA is 37. 8% at an average output power of 33. 3 dBm. The designed power amplifier can be aoolied in the WCDMA system.
