http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
한만갑,최국선,이재욱 한국자원공학회 2008 한국자원공학회지 Vol.45 No.2
The scarcity of raw materials from rare metals holds significant conflict potentials as global demand increases rapidly. In this study, we carried out several analysis on patent documents for the preparation of high purity materials from rare metals. The patents including abstracts, claims and drawings from 1976 up to 2006 were surveyed and 1,000 patents were collected finally. The patents were investigated as to countries, assignees, technologies and rare metal elements. Furthermore, we carried out the comparative analysis for technological level of assignee countries with United States patents. The top 5 assignee countries are Japan, United States, Korea, Germany and the United Kingdom. Especially Japan and United States play important role in this area as holding 775 patents.