Abstract: The present invention provides a crime prevention structure for a steel door. A steel door comprises an indoor panel, an outdoor panel, a sound-insulating core filled in a space formed between inner surfaces of the panels, and a high hardness metal plate that is thicker than plate thickness of the panels wherein the metal plate is provided between the sound-insulating core and an entire inner surface area, except sections for mounting door components, of at least one of the panels. In one preferred aspect, the metal plate is provided at the entire inner surface area, except portions for mounting door components, of the indoor panel.

Abstract: The hothouse for cultivation according to the present invention relates especially to a hothouse for cultivation enclosed with transparent members, wherein reflexion plates are provided on the northern side for reflecting the sunlight toward the soil surface inside the hothouse, and also to a hothouse enclosed with transparent members, wherein the hothouse comprises a shutter which can be opened and closed freely, and is switchable between two types of hothouses which are a hothouse composed only of the transparent members and a double hothouse comprising a heat insulation space between the shutter completely closed and the transparent members, so that the heat of the sunlight received by the hothouse for cultivation is most effectively used and kept in the hothouse.