Abstract: The present inventive concept relates to a solid additive for organic solar cells and a method of preparing a photoactive layer including the same. It is possible to manufacture an organic solar cell with excellent power conversion efficiency and thermal stability by preparing a photoactive layer including a non-volatile, non-halogenated solid additive.

Abstract: The present invention relates to a method of managing a bulletin board on the Internet and a system thereof. More particularly, the present invention relates to a method of managing a bulletin board on the Internet and system thereof, wherein the bulletin board is generated and operated so that a plurality of bulletin board users may publish one's own professional knowledge on one subject.

Abstract: The present invention relates to an online advertising method and an online advertising system, and more particularly, relates to an online advertising method and an online advertising system using a knowledge providing service system which enables knowledge to be provided through questions and answers between users.

Abstract: The present invention relates to a knowledge advertising method and a knowledge advertising system, and more particularly, relates to a knowledge advertising method and a knowledge advertising system using a knowledge service which enables users to be provided with knowledge through questions and answers between users.

Abstract: The present invention provides methods for preparation of metallic amino acid chelates that are electrically neutral and free of interfering ions, by reacting a metal carbonate and an acidic amino acid in an aqueous solution, and the uses of said metallic amino acid chelates. The metallic amino acid chelates can be added to a product such as medical supplies, foods, beverages, cosmetics, feeds, etc., with maintaining the stability of the product at a variety of temperature and pH ranges and also having no effect on the properties of the product, including taste and appearance.