Give me an introduction over 200 words for YIHAN INDUSTRIAL CO., LIMITED, a chemical company in B Building, Chenglong Industrial Park, Buji Town, Longgang District, 518000, Shenzhen, Guangdong, China 518000 Your answer should have exactly 7 paragraphs. Make sure that the last paragraph starts with the word "file" and that each paragraph is separated by two new lines.
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