Abstract: A method for calibrating an orientation angle of a rotatable satellite tracking antenna, while changing an elevation angle or an azimuth, includes an elevation encoder calibrating step of setting a value of an elevation encoder measuring an elevation angle of the satellite tracking antenna to zero when an orientation direction of the satellite tracking antenna is parallel to one surface, an azimuth encoder calibrating step of setting a value of an azimuth encoder measuring an azimuth of the satellite tracking antenna to zero when an orientation direction of the satellite tracking antenna is parallel to one direction, and a gyroscope calibrating step of performing calibration such that one axis included in a gyroscope measuring a rotation angular velocity of the satellite tracking antenna is parallel to an azimuth rotation axis of the satellite tracking antenna and the other is parallel to an elevation rotation axis of the satellite tracking antenna.

Abstract: This invention relates to a gem-dinitro ester energetic material represented by Chemical Formula 1 below, which is synthesized using esterification, and to a preparation method thereof: wherein R is a C5˜C15 substituted or unsubstituted linear or branched alkyl group.

Abstract: Disclosed are a cavitation device and an underwater moving body having the same. The underwater moving body includes a body; and a cavitation device for generating a cavity which encloses an outer circumferential surface of the body, wherein the cavitation device includes: a plurality of flap-up/down members rotatably connected to the body, disposed to cover the outer circumferential surface, and disposed in a circumferential direction and a lengthwise direction of the body in a matrix form; and a pressing module for flapping up the flap-up/down members such that the cavity is generated, as the flap-up/down members being rotated are inclined from the outer circumferential surface. Under this configuration, the cavitation device can freely generate a partial cavity or a super cavity on the surface of the underwater moving body. Furthermore, a ventilation module for forming a ventilated cavity may be coupled to the cavitation device.

Abstract: A heat-flux gage, a manufacturing method and a manufacturing device thereof which are improved from circular foil heat-flux gage disposed in ASTM E511 comprise: a cylindrical body having a receiving space therein, and a foil mounting hole on one end thereof; a foil including a heat absorption surface, an inner surface facing the heat absorption surface, and a radiant side surface connecting the heat absorption surface and the inner surface, wherein the inner surface faces toward the receiving space and the radiant side surface is contacted to a side surface of the foil mounting hole; a foil lead wire connected on a center of the inner surface of the foil; a body lead wire connected to an opposite end of the foil mounting hole on the cylindrical body; and a filler filled in the inner receiving space, to prevent the foil lead wire from being damaged by fixing the foil lead wire.

Abstract: There is an ion mobility spectrometer(IMS) comprising a ion drift tube comprising a reaction region, a shutter grid, a drift region and a collector; an inlet for introducing a carrier gas into the reaction region; and an ionization source in the reaction region, wherein flexible PCBs (printed circuit board) are fixed onto the surface of the ion drift tube to develop electric fields along the axis of the reaction region and the drift region for the movement of ions generated in the reaction region to the collector.

Abstract: A compactable composite explosive consisting of 90 weight % to 95 weight % of a raw explosive material being RDX, 5 weight % to 10 weight % of ethylene vinyl acetate copolymer resin containing vinyl acetate in a content of 10 % to 20 % and 0 weight % to 0.5 weight % of dioctyl adipate (D.O.A.) or graphite. This composite explosive is usable as a main charge or a booster of a highly precise arms system. The invention also provides a method for producing a compactable composite explosive, which comprises the steps of dissolving a binder of ethylene vinyl acetate copolymer resin in a solvent of toluene to prepare a solution, injecting the solution into RDX dispersed in a water, forming a granular product from the obtained mixture, distilling primarily the product, *adding toluene into the product, and distilling secondarily the product. The amount of added toluene is 1.0 time to 3.0 times the amount of the binder measured after the primary distillation.

Abstract: A manufacturing method for the production of aluminum-lithium alloys at low cost is disclosed which includes enclosing lithium with aluminum by means of a cold extrusion of pure lithium and melting the aluminum-sealed lithium ingots in an ambient atmospheric condition. The extrusion process can be simply performed in air as well as in an inert atmosphere at room temperature. The atmospheric melting of aluminum-lithium alloys is performed by immersing and agitating aluminum-sealed lithium ingots beneath the surface of molten aluminum with a graphite plunger.