目的探讨分析高性能战斗机飞行员+Gz耐力选拔方法及结果。方法采用横断面研究方法,采集1743名飞行员的+Gz耐力选拔数据,对选拔方法、合格率及其与年龄、飞行时间的关系进行了分析和探讨。结果高性能战斗机飞行员在进行+Gz耐力选拔时,允...目的探讨分析高性能战斗机飞行员+Gz耐力选拔方法及结果。方法采用横断面研究方法,采集1743名飞行员的+Gz耐力选拔数据,对选拔方法、合格率及其与年龄、飞行时间的关系进行了分析和探讨。结果高性能战斗机飞行员在进行+Gz耐力选拔时,允许采用HP动作的呼吸方式,没有严格控制肌肉紧张用力。1743名飞行员中有1569人的+Gz耐力达到4.25 G持续10 s,合格率为90.0%。飞行员选拔合格率与年龄(r=0.891,P=0.000)及飞行时间(r=0.9281,P=0.004)存在着显著相关性。到达+Gz耐力终点时,有39.3%的飞行员发生视力变化,近意识丧失(G-induced almost loss of consciousness,A-LOC)发生率为1.7%,加速度导致的意识丧失(G-induced loss of consciousness,G-LOC)发生率为2.6%。结论在新型载人离心机上完成的高性能战斗机飞行员+Gz耐力选拔合格率高,较少的+Gz暴露次数、规范的呼吸方式和未控制肌肉紧张用力可能是高合格率的重要原因。展开更多
The way of neutral point to earth via full compensation arc suppression coil can solve the problem of residual current compensation in coal mine power network effectively. Based on the analysis on the grounding curren...The way of neutral point to earth via full compensation arc suppression coil can solve the problem of residual current compensation in coal mine power network effectively. Based on the analysis on the grounding current detection results of Xieqiao coal mine, the conclusion that harmonic component of grounding current is dominated by higher harmonics with complex harmonic sources in coal mine power network system was obtained. The influences of harmonic source type and fault point position on harmonic voltage and harmonic current were analyzed theoretically. The influences of earthed fault feeder detection result and the estimation errors of parameters to earth on residual current compensation were analyzed. A new thought of residual current prediction and the selections of model method and control method were proposed on this basis. The simulation results prove that harmonic amplitudes of zero sequence voltage and zero sequence current are determined by harmonic source type as well as fault point position in coal mine power network, and also prove that zero sequence voltage detection can avoid the unstable problem of coal mine power network system caused by undercompensation of capacitive current. Finally, the experimental device of full compensation arc suppression coil is introduced.展开更多
文摘目的探讨分析高性能战斗机飞行员+Gz耐力选拔方法及结果。方法采用横断面研究方法,采集1743名飞行员的+Gz耐力选拔数据,对选拔方法、合格率及其与年龄、飞行时间的关系进行了分析和探讨。结果高性能战斗机飞行员在进行+Gz耐力选拔时,允许采用HP动作的呼吸方式,没有严格控制肌肉紧张用力。1743名飞行员中有1569人的+Gz耐力达到4.25 G持续10 s,合格率为90.0%。飞行员选拔合格率与年龄(r=0.891,P=0.000)及飞行时间(r=0.9281,P=0.004)存在着显著相关性。到达+Gz耐力终点时,有39.3%的飞行员发生视力变化,近意识丧失(G-induced almost loss of consciousness,A-LOC)发生率为1.7%,加速度导致的意识丧失(G-induced loss of consciousness,G-LOC)发生率为2.6%。结论在新型载人离心机上完成的高性能战斗机飞行员+Gz耐力选拔合格率高,较少的+Gz暴露次数、规范的呼吸方式和未控制肌肉紧张用力可能是高合格率的重要原因。
基金The financial support from the National Natural Science Foundation of China (No. 51107143)
文摘The way of neutral point to earth via full compensation arc suppression coil can solve the problem of residual current compensation in coal mine power network effectively. Based on the analysis on the grounding current detection results of Xieqiao coal mine, the conclusion that harmonic component of grounding current is dominated by higher harmonics with complex harmonic sources in coal mine power network system was obtained. The influences of harmonic source type and fault point position on harmonic voltage and harmonic current were analyzed theoretically. The influences of earthed fault feeder detection result and the estimation errors of parameters to earth on residual current compensation were analyzed. A new thought of residual current prediction and the selections of model method and control method were proposed on this basis. The simulation results prove that harmonic amplitudes of zero sequence voltage and zero sequence current are determined by harmonic source type as well as fault point position in coal mine power network, and also prove that zero sequence voltage detection can avoid the unstable problem of coal mine power network system caused by undercompensation of capacitive current. Finally, the experimental device of full compensation arc suppression coil is introduced.
