Abstract: The present invention provides a method of recovering a (meth)acrylic acid ester, which comprises the steps of: (a) carrying out an esterification reaction between an alcohol and (meth)acrylic acid in the presence of a catalyst to obtain a (meth)acrylic acid ester, wherein a byproduct is generated together with the (meth)acrylic acid ester; and (b) subjecting the byproduct generated in step (a) to a reaction with a catalyst and water in a reactor, wherein the water is fed into the reactor in order that water content exceeds 0 wt % but is 10 wt % or less in the reactor based on the total weight of reactants comprising the byproduct, the catalyst and the water, and thereby separating the (meth)acrylic acid, the alcohol and the (meth)acrylic acid ester contained in the byproduct from the byproduct to obtain the (meth)acrylic acid, the alcohol and the (meth)acrylic acid ester as a recovered product.

Abstract: An antenna apparatus allows for internal impedance matching by employing an internal matching device therein. The antenna apparatus includes a board body formed of a dielectric material and having a flat structure. The antenna apparatus also includes an antenna device disposed on an upper surface of the board body, and the internal matching device disposed on a lower surface of the board body. The antenna device extends from a feed point and has a first impedance. The internal matching device is connected to the antenna device and has a second impedance used for matching the first impedance with a reference impedance. The antenna device and the internal matching device resonate at the reference impedance in a specific frequency band when a voltage is supplied through the feed point.

Abstract: A multi-band antenna apparatus using a multiple frequency band is provided. The apparatus includes a substrate body formed in a flat plate structure having a preset thickness and in which at least one dielectric plate is stacked, a power supply line, disposed at the substrate body and connected to an external power source, for forming an electromagnetic field when power is supplied from the external power source, a radiation line, separated from the power supply line using the dielectric plate as the boundary in the substrate body, for forming an overlapping area overlapped with the power supply line along one axis through at least a portion, and for resonating in a frequency band determined according to the overlapping area when the electromagnetic field is formed, and a ground plate disposed in at least one an upper ground area and a lower ground area of the substrate body, for grounding the radiation line by contacting with the radiation line.

Abstract: The present invention provides a method of recovering a (meth)acrylic acid ester, which comprises the steps of: (a) carrying out an esterification reaction between an alcohol and (meth)acrylic acid in the presence of a catalyst to obtain a (meth)acrylic acid ester, wherein a byproduct is generated together with the (meth)acrylic acid ester; and (b) subjecting the byproduct generated in step (a) to a reaction with a catalyst and water in a reactor, wherein the water is fed into the reactor in order that water content exceeds 0 wt % but is 10 wt % or less in the reactor based on the total weight of reactants comprising the byproduct, the catalyst and the water, and thereby separating the (meth)acrylic acid, the alcohol and the (meth)acrylic acid ester contained in the byproduct from the byproduct to obtain the (meth)acrylic acid, the alcohol and the (meth)acrylic acid ester as a recovered product.

Abstract: A multi-band antenna apparatus using a multiple frequency band is provided. The apparatus includes a substrate body formed in a flat plate structure having a preset thickness and in which at least one dielectric plate is stacked, a power supply line, disposed at the substrate body and connected to an external power source, for forming an electromagnetic field when power is supplied from the external power source, a radiation line, separated from the power supply line using the dielectric plate as the boundary in the substrate body, for forming an overlapping area overlapped with the power supply line along one axis through at least a portion, and for resonating in a frequency band determined according to the overlapping area when the electromagnetic field is formed, and a ground plate disposed in at least one an upper ground area and a lower ground area of the substrate body, for grounding the radiation line by contacting with the radiation line.

Abstract: An antenna apparatus allows for internal impedance matching by employing an internal matching device therein. The antenna apparatus includes a board body formed of a dielectric material and having a flat structure. The antenna apparatus also includes an antenna device disposed on an upper surface of the board body, and the internal matching device disposed on a lower surface of the board body. The antenna device extends from a feed point and has a first impedance. The internal matching device is connected to the antenna device and has a second impedance used for matching the first impedance with a reference impedance. The antenna device and the internal matching device resonate at the reference impedance in a specific frequency band when a voltage is supplied through the feed point.