A remaining capacity equalizing device is provided having an inductance connected to a reference node of a battery pack and first and second switching elements. The reflector element is also adapted to direct the optical signal toward the data storage medium. 5, and magnetic head which is mounted on an integrated circuit suspension so that a total inductance is reduced to be not more than 65 nH and having a magnetic core which is not more than 35 m of length, wherein a part of the magnetic core being formed by a magnetic film having a resistivity exceeding at least 50 cm or by a multilayer film consisting of a magnetic film and an insulating film. The piston member is preferably provided with a single seal gasket that prevents leakage of gas towards the outside through the sliding coupling of the piston member within the respective guide bushing. The methods involve adsorbing the analytes to a substrate under a plurality of different selectivity conditions, and detecting the analytes retained on the substrate by desorption spectrometry The methods are useful in biology and medicine, including clinical diagnostics and drug discovery.