Abstract: A massive multiple-input multiple-output (MIMO) antenna apparatus and a heat dissipation device therefor are disclosed. The present disclosure according to at least one embodiment provides a massive MIMO antenna apparatus including a board, a first blowing unit, and a second blowing unit. The board has at least one board surface that holds a distributed arrangement of a plurality of heat-generating components, has a width and a length longer than the width, and includes a first section having a first amount of heat generation and a second section having a second amount of heat generation greater than the first amount of heat generation, the first section and the second section being partitioned along a length direction of the board.

Abstract: The present invention can provide light-colored magnetic particles having a zirconium oxide coating layer formed on a magnetic core, and having a silver coating layer formed on the zirconium oxide coating layer, and a part of the surface of the zirconium oxide coating layer is exposed to the outside, but chemical resistance is excellent, and thus the magnetic particles hardly cause a change of magnetic characteristics so as to be suitable for security elements.

Abstract: The present invention relates to a security device comprising a colloidal crystal which exhibits excellent visibility and is also easily manufactured. The security device, according to the present invention, comprises: a substrate; a groove part formed on the substrate; a colloidal crystal positioned in the groove part; and an aging film. The security device, according to the present invention, exhibits excellent security and visibility, and thus may be used for securities, credit cards, security cards, anti-forgery products, etc.

Abstract: The present invention relates to a security device comprising a colloidal crystal which exhibits excellent visibility and is also easily manufactured. The security device, according to the present invention, comprises: a substrate; a groove part formed on the substrate; a colloidal crystal positioned in the groove part; and an aging film. The security device, according to the present invention, exhibits excellent security and visibility, and thus may be used for securities, credit cards, security cards, anti-forgery products, etc.

Abstract: The present invention can provide light-colored magnetic particles having a zirconium oxide coating layer formed on a magnetic core, and having a silver coating layer formed on the zirconium oxide coating layer, and a part of the surface of the zirconium oxide coating layer is exposed to the outside, but chemical resistance is excellent, and thus the magnetic particles hardly cause a change of magnetic characteristics so as to be suitable for security elements.