Abstract: The present invention is intended for providing a system and method of detecting a forest gap occurring in a city and monitoring a change in the forest gap. Thus, disclosed is the present invention comprising: a data input unit configured to input and receive LiDAR survey data; a pre-processing unit configured to remove a noise from the LiDAR survey data and classify each of point cloud data; a modeling unit configured to generate a canopy height model with respect to the point cloud data classified as the trees; a forest gap classification unit; and a forest gap change measurement unit.

Abstract: A device installed between a surface of a coating bath and an air knife equipment to produce a hot dip metal coated steel sheet to form a non-oxidation atmosphere in a surface of a coated steel sheet ascending from the coating bath, the device comprising: lower gas discharge bars spaced apart from the surface of the coating bath by a predetermined distance and discharging a non-oxidation gas in a direction of the surface of the coating bath along the surface of the coated steel sheet; a side cover extending upwardly slopingly in a direction of the coated steel sheet from the sides of the lower gas discharge bars; and upper gas discharge bars formed at an upper end of the side cover and discharging a non-oxidation gas downwardly.

Abstract: The device of the present invention can enhance the quality of surface appearance through a nitrogen curtain section facilitating oxidation suppressing at a lower end portion of an air knife to suppress an oxide from being generated from an upper portion of a coating bath and block adsorption of the oxide to the surface of a coated layer. This device includes lower gas discharge bars spaced apart from the surface of the coating bath by a predetermined distance and discharging a nitrogen gas in a direction of the surface of the coating bath along a circumference of the coated steel sheet; a side cover extending upwardly slopingly in a direction of the coated steel sheet from the sides of the lower gas discharge bars; and upper gas discharge bars formed at an upper end of the side cover and discharging a nitrogen gas downwardly.

Abstract: Disclosed is a method for producing a zinc-aluminum-based alloy-coated steel sheet with superior workability and corrosion resistance by coating a base zinc-aluminum-based alloy-coated steel sheet in a coating bath comprising 35 to 55% by weight of zinc, 0.5 to 3% by weight of silicon, 0.005 to 1.0% by weight of chromium, 0.01 to 3.0% by weight of magnesium, 0.001 to 0.1% by weight of titanium, and the balance of aluminum and inevitable impurities.

Abstract: Disclosed is a method for producing a zinc-aluminum-based alloy-coated steel sheet with superior workability and corrosion resistance by coating a base zinc-aluminum-based alloy-coated steel sheet in a coating bath comprising 35 to 55% by weight of zinc, 0.5 to 3% by weight of silicon, 0.005 to 1.0% by weight of chromium, 0.01 to 3.0% by weight of magnesium, 0.001 to 0.1% by weight of titanium, and the balance of aluminum and inevitable impurities. With the method, it is possible to produce a zinc-aluminum-based alloy-coated steel sheet which exhibits superior workability through control of an intermetallic compound layer (Zn—Al—Si—Cr) and formation of AlCr2 due to Cr component present in the coating layer, reduces detachment of the coating layer and cracks of coating occurring during molding, exhibits superior corrosion resistance even after processing and has considerably superior corrosion resistance due to Mg2Si alloy phase and inhibition of oxide film formation.