Abstract: The present invention relates to a method for purifying key intermediates of Citalopram, i.e. 4-[4-(dimethylamino)-1-(4-fluorophenyl)-1-hydroxybutyl]-3-hydroxymethylbenzonitrile and a salt thereof. The method comprises dissolving crude 4-[4-(dimethylamino)-1-(4-fluorophenyl)-1-hydroxybutyl]-3-hydroxymethylbenzonitrile (compound of formula I containing formaldehyde impurity) with an organic solvent, adding a washing solution, controlling the temperature, stirring, leaving to stand for layering, and removing the aqueous layer, so as to obtain a purified organic solution of 4-[4-(dimethylamino)-1-(4-fluorophenyl)-1-hydroxybutyl]-3-hydroxymethylbenzonitrile. The method provided by the present invention can effectively remove aldehyde group-containing impurities in the intermediate. The method of the present invention has the advantages of simple operation, cheap raw materials and mild conditions, and is suitable for large-scale industrial production.

Abstract: The present invention provides a two-stage stiffness type elastomer combined device, including at least one small-stiffness elastic element and a large-stiffness elastic element, wherein the small-stiffness elastic element is arranged in an elastomer pre-compression device and is serially arranged with the large-stiffness elastic element under the action of a pre-compression load F1. The device has combined stiffness being hard at first and then becoming soft and is used as an elastic axle box suspension device of a railway vehicle, effectively solving the contradiction that a linear snaking critical operation speed of the vehicle and curve passing performance of the vehicle cannot be compromised.

Abstract: The present invention provides a variable stiffness positioning device for a railway vehicle bogie axle box. The variable stiffness positioning device includes a vertical elastomer arranged between the top face of an axle box bearing saddle and the bottom surface of a guide frame of a side fame, and a longitudinal elastomer arranged between the axle box bearing saddle and the front and back side faces of the guide frame of the side fame, the longitudinal elastomer is provided with at least one small-stiffness elastic element and a large-stiffness elastic element, and the small-stiffness elastic element is arranged in an elastomer pre-compression device and is serially arranged with the large-stiffness elastic element under the action of a pre-compression load F1.

Abstract: The present invention provides a variable stiffness positioning device for a railway vehicle bogie axle box. The variable stiffness positioning device includes a vertical elastomer arranged between the top face of an axle box bearing saddle and the bottom surface of a guide frame of a side fame, and a longitudinal elastomer arranged between the axle box bearing saddle and the front and back side faces of the guide frame of the side fame, the longitudinal elastomer is provided with at least one small-stiffness elastic element and a large-stiffness elastic element, and the small-stiffness elastic element is arranged in an elastomer pre-compression device and is serially arranged with the large-stiffness elastic element under the action of a pre-compression load F1.

Abstract: The present invention provides a two-stage stiffness type elastomer combined device, including at least one small-stiffness elastic element and a large-stiffness elastic element, wherein the small-stiffness elastic element is arranged in an elastomer pre-compression device and is serially arranged with the large-stiffness elastic element under the action of a pre-compression load F1. The device has combined stiffness being hard at first and then becoming soft and is used as an elastic axle box suspension device of a railway vehicle, effectively solving the contradiction that a linear snaking critical operation speed of the vehicle and curve passing performance of the vehicle cannot be compromised.