As water rises, locals use a makeshift pedestrian bridge to help them supply and evacuate in the Hunza River Valley in northern Pakistan.
巴基斯坦北部罕萨河谷，由于水势上涨，当地人利用一座临时搭建的桥帮助他们获取给养和疏散人员。
2
The working processes of the frequency-tracking phase-shift PWM controlled full bridge power supply load series resonant type DBD ozone generation power system are analyzed.
系统的分析了频率跟踪移相PWM控制全桥供电的串联谐振负载式DBD型臭氧发生器电源系统的工作过程。
3
A half bridge switching mode power supply (SMPS) based on PWM technology is introduced.