Phân tích tư tưởng của nhân dân qua đoạn thơ: Những người vợ nhớ chồng… Những cuộc đời đã hóa sông núi ta trong Đất nước của Nguyễn Khoa Điềm
3437
1
0
9 trang
Polychlorinated biphenyls (PCBs) are a family of chemicalcompounds which do not exist in nature but which are manmade.Commercial mixtures are clear, pale yellow liquidsmanufactured by the replacement of hydrogen atoms on thebiphenyl molecule by chlorine. The reaction is controlledaccording to the percentage replacement of hydrogen andresults in a product which contain chlorobiphenyls with oneor, more usually, several chlorine atoms attached to eachmolecule.
Nội dung trích xuất từ tài liệu:
ENCYCLOPEDIA OF ENVIRONMENTAL SCIENCE AND ENGINEERING - PCBs AND ASSOCIATED AROMATICS
