| 1. | Beijing hanzhiyuan electronics co . ltd is a sino - holland high - tech joint - venture majoring in the researching , manufacturing and marketing of piezoelectric ceramic transformer and power supply , a highly professional and innovative company 北京汉之源公司为中荷合资的高新技术企业,主要经营业务是研发生产销售压电陶瓷变压器及 |