Abstract: The heat-conducting resin sheet according to an aspect of the present invention comprises a thermally conductive plate-shaped particle, a thermally conductive spherical particle, and a resin, wherein the heat-conducting resin sheet has a thermal conductivity of 5 W/m·K or more and a 30% compressive strength B of 1500 kPa or less as measured at a compression rate of 1.0 mm/min. Furthermore, a volume ratio of the thermally conductive plate-shaped particle to the thermally conductive spherical particle (volume of thermally conductive plate-shaped particle/volume of thermally conductive spherical particle) is 30/70 to 90/10, and the total volume of the thermally conductive plate-shaped particle and the thermally conductive spherical particle is 30 to 90% by volume. According to the present invention, there can be provided a heat-conducting resin sheet that is excellent in the thermal conductivity and flexibility and can suppress the increase in the stress even when compressed quickly.

Abstract: In a quadrupole mass spectrometer which includes four parallel rod electrodes between opposite pairs of which overlapping voltages.+-.(U+V cos .omega. t) are applied (where U: a continuous voltage and V cos .omega. t: a radio-frequency voltage) and which effects mass-analysis by an electric field formed within the four parallel rod electrodes, at least one parameter of U, V and .omega. has two different values, and the values are changed over to select the first stable region or the second stable region, the first stable region being nearest to the original point and the second stable region being next near to the original point on the a - q plane (where a:ordinate, q:abscissa) showing "stability diagram", and the ions being able to pass through the four parallel electrodes under the conditions of the first and second stable regions, where the variable a=8eU/mr.sub.O.sup.2 .omega..sup.2, q=4eV/mr.sub.O.sup.2 .omega..sup.