Abstract: A novel semiconductor is provided. The semiconductor includes a first component, a second component, and an instruction portion. The first component includes a first memory circuit having a function of storing first setting information in a state where power is supplied, and a second memory circuit having a function of storing the first setting information in a state where power is not supplied. The second component includes a third memory circuit having a function of storing second setting information in a state where power is supplied, and a fourth memory circuit having a function of storing the second setting information in a state where power is not supplied. The instruction portion has a function of controlling whether power is supplied to each of the first component and the second component. Each of the second memory circuit and the fourth memory circuit includes a transistor including a metal oxide in a semiconductor layer where a channel is formed.

Abstract: A semiconductor device with a novel structure is provided. The semiconductor device includes a register. The register includes a flip-flop and a plurality of data retention circuits. The flip-flop includes a first transistor in which a semiconductor layer including a channel formation region is silicon, an input terminal of the flip-flop is electrically connected to each of output terminals of the data retention circuits, and an output terminal of the flip-flop is electrically connected to each of input terminals of the data retention circuits. The data retention circuits include a second transistor in which a semiconductor layer including a channel formation region is an oxide semiconductor, and when the second transistor is in a non-conduction state, the data retention circuits have a function of retaining a potential corresponding to data corresponding to a plurality of tasks.

Abstract: A cleaning tool includes: a head; and a cleaning body wrapped around the head. The head includes: a head body; and a projection that projects from the head body. The projection is retractable relative to the head body. The head may further include an elastic member that restores a positional relationship between the projection and the head body.

Abstract: A method of dewaxing a vegetable oil which comprises adjusting the temperature of a vegetable oil containing a wax to allow the wax to crystallize and subjecting the temperature-adjusted oil to filtration by means of a porous membrane having a critical surface tension (.gamma.c) of less than 33 dynes/cm and having an average pore diameter of 0.05 to 5 .mu.m, thereby selectively permeating the vegetable oil through the membrane while separating the wax from the vegetable oil. The process of the present invention is useful not only for dewaxing a vegetable oil but also for removing a wax together with a phospholipid, a free fatty acid and water from a crude vegetable oil.