Abstract: Provided is a method for preparing an oligomer including: supplying a monomer stream and a solvent stream to a reactor to perform an oligomerization reaction to prepare a reaction product; supplying a discharge stream from the reactor including the reaction product to a separation device and supplying a lower discharge stream from the separation device to a settling tank; adding an organic flocculant to the settling tank to settle and remove a polymer and supplying the lower discharge stream from the separation device from which the polymer is removed to a high boiling point separation column; and removing a high boiling point material from the lower portion in the high boiling point separation column and supplying an upper discharge stream including an oligomer to a solvent separation column.

Abstract: Disclosed herein are a self-powered type handrail sterilizing device and a device for collecting visitor information using the same. The self-powered type handrail sterilizing device includes: a housing having an opening fastened to a handrail of an escalator or a moving walk; a power unit installed at an inner side of the housing to convert a rotational motion depending on driving of the handrail into power; and a ultraviolet lamp module installed on an inner surface of the opening of the housing and configured to irradiate sterilizing light to the handrail through the power of the power unit.

Abstract: Disclosed herein are a self-powered type handrail sterilizing device and a device for collecting visitor information using the same. The self-powered type handrail sterilizing device includes: a housing having an opening fastened to a handrail of an escalator or a moving walk; a power unit installed at an inner side of the housing to convert a rotational motion depending on driving of the handrail into power; and a ultraviolet lamp module installed on an inner surface of the opening of the housing and configured to irradiate sterilizing light to the handrail through the power of the power unit.