Abstract: A fluid level measurement system using a buoyant body includes a guide part installed in a direction perpendicular to the bottom surface of a fluid storage tank, and provided with a space in which a fluid can move therein; a buoyant body inserted into the guide part, and configured to float along the surface of the fluid inside the guide part; and a measurement part coupled to the top end of the guide part, and configured to measure the level of the surface of the fluid inside the fluid storage tank by transmitting a signal toward the buoyant body in the inner space of the guide part and then receiving a signal reflected from the buoyant body.

Abstract: A thermal conduction vacuum gauge using a Peltier tip is provided. The vacuum gauge for measuring the pressure in a vacuum chamber includes: a signal generator that drives an electric current; an ammeter connected to the signal generator for measuring the current; a bridge circuit consisting of junctions of thermocouple wires, which is connected to the ammeter, wherein one junction of the dissimilar metallic wires is made in the form of a Peltier tip inserted into the vacuum chamber; and a lock-in amplifier connected to the two symmetrical points of the bridge circuit for detecting a voltage signal due to the temperature oscillation at the Peltier tip and thus measuring the pressure in the vacuum chamber.

Abstract: A thermal conduction vacuum gauge using a Peltier tip is provided. The vacuum gauge for measuring the pressure in a vacuum chamber includes: a signal generator that drives an electric current; an ammeter connected to the signal generator for measuring the current; a bridge circuit consisting of junctions of thermocouple wires, which is connected to the ammeter, wherein one junction of the dissimilar metallic wires is made in the form of a Peltier tip inserted into the vacuum chamber; and a lock-in amplifier connected to the two symmetrical points of the bridge circuit for detecting a voltage signal due to the temperature oscillation at the Peltier tip and thus measuring the pressure in the vacuum chamber.

Abstract: A method for forming a chromium oxide film on the surface of a stainless steel sample. The method includes: (a) placing a sample having stainless a steel surface into a vacuum furnace, evacuating the vacuum furnace to a pressure of 2×10−7 to 3×10−7 Torr, and heating the vacuum furnace to 450 to 600° C. at a rate of 5 to 10° C./min; (b) maintaining the vacuum furnace for 10 to 20 minutes at a temperature of 450 to 600° C. to remove foreign materials from the surface of the stainless steel sample and to extract chromium atoms from the stainless steel substrate; and (c) supplying oxygen to the vacuum furnace while maintaining the temperature until oxygen partial pressure reaches 1×10−9 to 2.5×10−7 Torr, so the extracted chromium atoms react with oxygen, producing a chromium oxide (Cr2O3) film on the surface of the stainless steel.