You can Google it. but my shake i Bookmarked these links may this will help for you too,
for learn ui5 refer these,
http://scn.sap.com/community/developer-center/front-end/blog/2013/12/11/what-is-openui5-sapui5
http://scn.sap.com/docs/DOC-31625
http://allthatjs.com/2012/02/23/getting-started-with-sapui5/
for Gateway refer these,