Abstract: A content usage management system 1 comprises a user terminal 200a using a content as a digital production and a server 100 managing usage of the content in the user terminal 200a over a communication network 300; wherein the sever 100 includes a user right information DB 120 that memorizes right information regarding a usage right of the content entitled to a user who uses the terminal 200a and a content information generation unit 170 that generates LT which is right information indicating a part of usage right entitled to the user based upon a request from the user and that sends the LT to the sever terminal 200a; and the user terminal 200a includes a communication unit that receives the LT sent from the server 100 and a license information processing unit 260 that controls usage of the content according to the usage right indicated on the received LT.

Abstract: The mail gateway generates an identifier for each of attached files included in the e-mail addressed to a user and held in the mail server, and notifies the mail terminal belonging to the user of a list of generated IDs. When the user selects attached files that the user wants to attach to the e-mail from the list of IDs that is notified from the mail gateway, the mail gateway constructs e-mail including the selected attached files and the mail server transmits the constructed e-mail to receivers' addresses thereof.

Abstract: An explosion-proof battery includes a cover unit fit into an open portion of a cylindrical cup-like casing. The cover unit is electrically connected to a lead tab extended from an electricity generating unit installed in the casing. The cover unit includes a metal terminal plate of relatively high rigidity, a pressure sensitive plate in the form of a metal plate having relatively high flexibility and vulnerability, a fixing plate of insulating material, an electrical conductive member including an upwardly projecting portion and a base portion, and a ring-shaped gasket of insulating material. The terminal plate and the fixing plate have respective vent holes. The electrical conductive member and the pressure sensitive plate are connected to each other at a connecting portion on the projecting portion of the conductive member by welding. A tip end portion of the lead tab is connected to the base portion of the conductive member.

Abstract: An electric double layer capacitor has a pair of polarized electrodes in the form of electrode bodies each comprising a porous sintered body, and a pair of current collectors for collecting electric charges stored in the polarized electrodes, the current collectors being in the form of electrically conductive films. The electrically conductive films have surfaces dissolved by a solvent and joined to the electrode bodies with dissolved portions of the electrically conductive films being present in pores of the electrode bodies. The polarized electrodes and the current collectors are held in stable contact with each other, with a reduced contact resistance therebetween. The electric double layer capacitor thus has a small internal resistance.