In order to develop innovative solutions in science and technology, Japan Science and Technology Agency (JST) has published J-GLOBAL knowledge (JGk), which provides papers, patents, researchers' information, technological thesaurus, and scientific data, which have been accumulated by JST since 1957 as Linked Open Data. The total of all datasets surpasses 15.5 billion triples, and the JGk website provides a SPARQL endpoint to access the datasets. This paper describes several issues on schema design to construct such a large-scale Linked Data, and methods for linking to external datasets like DBpedia. Finally, we indicate performance problems and the future works.