Moving double-sided mirror

Figure 5.15. Construction of an interferometer manufactured by On-Line Technologies. Radiation hits the beamsplitter (A) and is reflected to a cube-comer retroreflector (D) onto one side of a moving doubie-sided mirror (C). The beam that is transmitted through the beamspiitter is reflected from a fixed mirror (B) to the other side of the moving double-sided mirror (C). (Reprodueed from [5], by permission of John Wiley Sons, Ltd. copyright 2002.)...

As discussed in Section 8.2 (Fig. 8.3), interparticle and wall friction, force dissipation from particle to particle, and sliding under shear cause differences in density distribution in a compact that is produced in a die with one-sided compression by one of the punches. To obtain a somewhat more uniform structure, compaction can be carried out by both punches. If both move at the same rate and for the same stroke length, thus exerting identical forces, and assuming uniform filling of the die, a mirror image of the density distributions that were shown in Fig. 8.3 (Section 8.2) develops along a neutral plane which, under those conditions, is located in the middle of the compact. Machines that operate in this manner may be identified as presses with double pressure (see also below). 

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