Abstract: A rail breakage detection device includes a first core part provided to a first cable connecting an electrical neutral point of an impedance bond that electrically connects a first rail and a second rail to the first rail, a second core part provided to a second cable connecting the electrical neutral point of the impedance bond to the second rail, a first coil wound around the first core part to generate a first electromotive force in accordance with a current variation occurring in the first cable, a second coil connected electrically to the first coil and wound around the second core part to generate a second electromotive force in accordance with a current variation occurring in the second cable, and a CPU to determine that the first or second rail is broken based on an electromotive force that is a sum of the first and second electromotive forces.

Abstract: A method can produce a divinyl ether compound having an alkylene skeleton from an alkanediol and acetylene at a rapid production rate and a high reaction yield. In the production method, a compound of formula (1) wherein R1 is an alkylene group having 4 to 20 carbon atoms, may be reacted with acetylene in the presence of an alkali metal catalyst to produce a compound of formula (2) and the reaction may be performed in the absence of a solvent.

Abstract: A method of purifying a divinyl ether compound having an alkylene skeleton may take place with low energy and in a simplified manner. Such a method for producing a divinyl ether compound may include: reacting a compound of formula (1) wherein R1 is an alkylene group having 4 to 20 carbon atoms, with acetylene by using an alkali metal catalyst; and purifying the divinyl ether compound of formula (2) which is obtained in the reacting, without an extraction.