Disclosed is a plasticizer composition which comprises an ester-based plasticizer and an ether compound and exhibits improved workability and heat loss in proportion to content of the ether compound. A peripheral transistor includes a lower electrode, a second inter-electrode insulating film and an upper electrode. The method comprises a first step to hold oil in the bearing gap, and a second step to locate the stopper on the peripheral wall being apart from the interface of the oil to fix the stopper by LASER welding. Providing cancellation in the subband of the relayed interference produces larger interference cancellation factors than those obtained in conventional broadband cancellation systems. The digital signature may be a private-key digital signature. In one embodiment, a smart tray for dispensing medicaments includes: a housing; an information storage device that maintains inventory information regarding medicament units in the tray; and a communication device to transfer the inventory information between the information storage device and an external computing apparatus to facilitate inventory maintenance.