| 摘要 |
FIELD: seismology. ^ SUBSTANCE: seismograph has permanent magnets secured to the base and arranged symmetrically with respect to the direction of rolling of the inertia mass. Some magnets are mounted above the inertia mass, the others are below the inertia mass which is made of a magnetically soft material. The polarity of the top and bottom magnets is the same in space. The inner sides of the magnets are spaced to provide free oscillation of the inertia mass. ^ EFFECT: increased period of the natural oscillation. ^ 1 dwg |
