Abstract: An acceleration generator 20 includes: a moving member (21, 25) that performs a periodic translational motion along a particular straight line; a first operating part (24) that applies a first force that varies in magnitude depending on the relative position thereof with respect to the moving member to the moving member in a direction parallel to the particular straight line; and a second operating part (27) that applies a second force that varies in magnitude depending on the relative position thereof with respect to the moving member to the moving member in a direction parallel to the particular straight line. The moving member performs a translational motion in which the acceleration thereof in the positive direction and the acceleration thereof in the negative direction are asymmetric in one period.

Abstract: An acceleration generator 20 includes: a moving member (21, 25) that performs a periodic translational motion along a particular straight line; a first operating part (24) that applies a first force that varies in magnitude depending on the relative position thereof with respect to the moving member to the moving member in a direction parallel to the particular straight line; and a second operating part (27) that applies a second force that varies in magnitude depending on the relative position thereof with respect to the moving member to the moving member in a direction parallel to the particular straight line. The moving member performs a translational motion in which the acceleration thereof in the positive direction and the acceleration thereof in the negative direction are asymmetric in one period.

Abstract: An acceleration generator 20 includes: a moving member (21, 25) that performs a periodic translational motion along a particular straight line; a first operating part (24) that applies a first force that varies in magnitude depending on the relative position thereof with respect to the moving member to the moving member in a direction parallel to the particular straight line; and a second operating part (27) that applies a second force that varies in magnitude depending on the relative position thereof with respect to the moving member to the moving member in a direction parallel to the particular straight line. The moving member performs a translational motion in which the acceleration thereof in the positive direction and the acceleration thereof in the negative direction are asymmetric in one period.

Abstract: A method for machining a board includes forming a backup board, supporting the board by the backup board and machining the board while the board is supported by the backup board. The backup board has a fibrous layer and a surface layer formed on one side of the fibrous layer, the surface layer being in contact with the board during said supporting machining the board. The backup board is formed by: forming an impregnated fibrous mat by impregnating a thermosetting adhesive into a fibrous mat of the kenaf fibers, the kenaf fibers; forming the fibrous layer having a density of about 600-900 kg/m3 by curing the impregnated fibrous mat; forming a resin paper by impregnating a thermosetting resin into a paper; and forming the surface layer on said one side of the fibrous layer by curing the resin paper.

Abstract: An acceleration generator 20 includes: a moving member (21, 25) that performs a periodic translational motion along a particular straight line; a first operating part (24) that applies a first force that varies in magnitude depending on the relative position thereof with respect to the moving member to the moving member in a direction parallel to the particular straight line; and a second operating part (27) that applies a second force that varies in magnitude depending on the relative position thereof with respect to the moving member to the moving member in a direction parallel to the particular straight line. The moving member performs a translational motion in which the acceleration thereof in the positive direction and the acceleration thereof in the negative direction are asymmetric in one period.

Abstract: A backup board for use in a machining process includes a fibrous layer, at least one side of the fibrous layer being provided with a surface layer adhered and laminated thereon, wherein the surface layer is made of a cured paper impregnated with a thermosetting resin. The fibrous layer has a density of about 600˜900 kg/m3 and includes kenaf fibers adhered together by impregnating a thermosetting adhesive into a fibrous mat of the kenaf fibers, the kenaf fibers having an average length of about 10˜200 mm and an average diameter of about 10˜300 ?m.