Trains and elevators, as usual, let the phone signal quality is poor. To help solve this problem, the Federal Institute of Technology Lausanne (EPFL) A team of researchers using 200mw green laser processing train car glass, while maintaining the insulation performance situation, enhance cell phone signal quality. According to the researchers, said one third of the energy used to train cabin cool or heat, of which 3% of the energy through the car window dissemination. To assist thermal insulation, double-glazed windows are often equipped with compartments thin metal coating with the light, but reflects heat away, thus using a minimum of energy to maintain the desired temperature. These coatings will enhance the energy efficiency of four.
http://www.everyonetobuy.com/200mw-green-laser-pointer-adjustable-flashlight-burning-match.html
Unfortunately, this is not only metal coating reflects heat, but also hinder the cell phone signal. Since the railway vehicle is made of a metal, a metal coating on the windows effectively convert them into a Faraday cage to prevent electromagnetic signal into the cause of bad cell phone signal quality. Standard solution to this problem is to install a signal relay device in the car, but this means using more energy and more money to install and maintain. Another way is to change the EPFL metal coating, making the window more selective, allowing centimeter-sized electromagnetic wave through the barrier in the micron size of the heat wave.
http://www.everyonetobuy.com/high-powered-20000mw-blue-laser-pointer-pen.html
The researchers used a high-precision 20000mw blue laser removal of metal coating thickness of 2.5%, and a specific pattern engraved naked eye can not see, and let the light through electromagnetic waves, but still block the heat. According to EPFL he said that the prototype has passed the Swiss BLS Lötschberg Railway (BLS) field test to prove the success of this approach.

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