2. Some cities in our country arrange to try to sound the air defense alarm on a certain day every year. The test usually lasts 15 minutes, and sounds in the order of air raid alarm, emergency alarm and disarming alarm. One is to mourn the people killed in the air raid in the city, the other is to test the civil air defense equipment, and the third is to carry out national defense education.
3. Air defense warning is mainly used for disaster prediction and emergency notification in emergency rescue and disaster relief and sudden accidents, and used for civil air defense in wartime. It is the basic means for people's governments at all levels to carry out civil air defense command and organize personnel evacuation, and it is an alarm sounded when the city is threatened by air strikes to remind people to pay attention to air defense.
4. Alarms can be divided into three types: electric alarm, electroacoustic alarm and manual alarm. The electric alarm is the main device of the alarm, and the electroacoustic alarm which converts electric energy into sound consists of the host power amplifier and the speaker. Manual alarm is a supplementary early warning device for electric alarm and electroacoustic alarm.
Extended data:
1. Wanxian Massacre, also known as Wanxian "Ninth Five-Year Massacre", took place in Wanxian County, Sichuan Province (now Wanzhou District, Chongqing). 1On September 5th, 926, British imperialist warships shelled Wanxian County, Sichuan Province, killing 604 soldiers and civilians in China, injuring 398 others, destroying more than 1,000 houses and causing property losses of about 20 million yuan.
2. On September 7th, 1926, Yang Sen called people from all walks of life in Wanxian County to discuss the aftermath of the tragedy. It is decided to turn Guanshan (cemetery) in Wanxian County into a martyrs' cemetery in the Ninth Five-Year Plan, set up an office in the Ninth Five-Year Plan Park, and build a library in the Park in the Ninth Five-Year Plan (opened on April 5, 1928). 1928165438+1October 15. Wanxian Commercial Port Bureau decided to build the Ninth Five-Year Plan Monument in the Ninth Five-Year Plan Park.
Three, the general air defense alarm equipment is set on the roof of the city building, and is managed by the security department of the army or the streets, enterprises and institutions.
(1) Early evacuation refers to the planned evacuation of urban residents, materials, factories and facilities. When the country predicts and detects that war will break out, before the country declares a state of war, according to the mobilization order issued by the country or the war zone.
(2) Emergency evacuation refers to the planned evacuation of urban residents during the period from the declaration of a state of war to the outbreak of war.
(3) Emergency evacuation, usually refers to the evacuation covert action carried out within 24 hours before the first air raid or during the air raid interval. When organizing emergency evacuation, it is necessary to make overall arrangements, allocate and use civil air defense fortifications with emphasis, and organize various guarantees according to terrain conditions, population size and density, and layout of fortifications. And the principle of overall consideration and key protection.
References:
Baidu Encyclopedia-Air Defense Alert