To ensure Class 4 and Class 3B laser beams do not escape from laser laboratory or medical facilities, including hospital theatres, certified laser blocking material should be installed. Ordinary curtains are rarely capable of stopping a laser beam and specially designed certified laser blocking material must be used (certified to IEC/EN 60825-4).
Also, production facilities using Class 1 lasers, which are Class 4 under service conditions, may require ceiling-mounted curtains to allow other work to continue safely in the same room during service…
英國鐵路公司如何推動凈零排放
It would be better if the trains had good coverage of the country. Large areas have no easy connection and so cars (or buses?) and lorries are still...