Université Frères Mentouri - Constantine 1
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- Écrit par Redaction Web 1
- Catégorie : Articles à Lire
- Publication : 9 juin 2015
- Affichages : 3609
In July 2010, the Chinese government sent a chill through the world's high-technology industries when it announced a 37% cut in export quotas for rare-earth elements — a group of 17 metallic elements that are essential ingredients in display screens, low-energy lighting, high-powered lasers and a host of other twenty-first-century products.