Abstract: A lithium ion secondary battery that can operate in a high-temperature environment of 85° C. The lithium ion secondary battery includes a positive electrode active material that can store and release lithium ions Li?, a positive electrode binder that binds the positive electrode active material, a negative electrode active material that can store and release lithium ions Li+, a negative electrode binder that binds the negative electrode active material, and an electrolytic solution containing an organic solvent and an imide-based lithium salt. The negative electrode active material is previously doped with lithium ions. The positive electrode binder has a Hansen solubility parameter-based relative energy difference (RED) value of more than 1 with respect to the electrolytic solution.

Abstract: In order to suppress the amount of time needed for the start-up of a microwave tube carried out when voltage fed from a power source has decreased, while avoiding increase in scale of a power storage unit, this power supply device includes: a power supply unit that supplies power fed from the power source to the microwave tube that is provided with a cathode, a heater for heating the cathode, an anode, and a collector; a power storage unit that stores the fed power and, if the voltage of the fed power decreases, supplies stored power that is power obtained by the power storing, to the microwave tube; and a power supply switching unit that, if the voltage of the fed power decreases, stops supplying the stored power to the anode and does not stop supplying the stored power to the heater.

Abstract: Proposed are the welding conditions under which welds are always stably formed such that the difference in hardness between flash-butt welds and rail base metal and the deflection in a bending test are in better ranges. A plurality of pieces of rail base metal are joined via welds formed by flash-butt welding, where the rail base metal has a chemical composition containing C: 0.60 to 1.20 mass %, Si: 0.10 to 1.50 mass %, Mn: 0.10 to 1.50 mass %, and Cr: 0.10 to 1.50 mass %, with the balance being Fe and inevitable impurities, and the flash-butt welding is performed with an amount of welding heat input of 1.50×105 kA2×sec or more and 4.50×105 kA2×sec or less.