英语翻译30 seconds of 4.5% to 5.5% O2 followed by 30 seconds of 21% O2 for 8 h/d during the daytime那个O2 就是氧气的意思

英语翻译30 seconds of 4.5% to 5.5% O2 followed by 30 seconds of 21% O2 for 8 h/d during the daytime那个O2 就是氧气的意思
英语翻译
30 seconds of 4.5% to 5.5% O2 followed by 30 seconds of 21% O2 for 8 h/d during the daytime
那个O2 就是氧气的意思

英语翻译30 seconds of 4.5% to 5.5% O2 followed by 30 seconds of 21% O2 for 8 h/d during the daytime那个O2 就是氧气的意思
4.5％至5.5％的氧气30秒,接着, 21％的氧气30秒, 每天8小时（8 hour/day）,在日间
这一句该分拆来看：
30 seconds of 4.5% to 5.5% O2
followed by
30 seconds of 21% O2
for 8 h/d during the daytime
猜这是说每天在日间时间,8小时的供氧气分量及每节的时长.
h/d = hour/day 时/天