Abstract: A method for manufacturing a catalyst support includes: heat-treating a crystalline carbon support in a temperature range from 700° C. to 1100° C. under a vapor atmosphere to increase a specific surface area of the carbon support; and applying a magnetic field to the increased specific surface area of the carbon support to remove an impurity.

Abstract: A method for manufacturing a catalyst support includes heat-treating a crystalline carbon support in a temperature range from 700° C. to 1100° C. under a vapor atmosphere to increase a specific surface area of the carbon support; and applying a magnetic field to the increased specific surface area of the carbon support to remove an impurity.

Abstract: A hi-fi audio device for reproducing and outputting a hi-fi sound source, the hi-fi audio device including: an operation unit configured to operate the hi-fi audio device; and a power supply unit comprising: an alternating current (AC) power supply unit configured to rectify alternating current supplied from an external power supply into first direct current and supply the first direct current to the operation unit; and a battery unit configured to supply second direct current to the operation unit, wherein the operation unit receives the first direct current and drives the hi-fi audio device when the operation does not reproduce a sound source, and receives the second direct current and drives the hi-fi audio device while the operation unit reproduces the sound source, and while the sound source is reproduced, the supply of the first direct current to the operation unit is blocked.

Abstract: A hi-fi audio device for reproducing and outputting a hi-fi sound source, the hi-fi audio device including: an operation unit configured to operate the hi-fi audio device; and a power supply unit comprising: an alternating current (AC) power supply unit configured to rectify alternating current supplied from an external power supply into first direct current and supply the first direct current to the operation unit; and a battery unit configured to supply second direct current to the operation unit, wherein the operation unit receives the first direct current and drives the hi-fi audio device when the operation does not reproduce a sound source, and receives the second direct current and drives the hi-fi audio device while the operation unit reproduces the sound source, and while the sound source is reproduced, the supply of the first direct current to the operation unit is blocked.

Abstract: A preparation method of a hollow carbon sphere includes preparing a hollow carbon sphere including fine pores by using mold particles and a material including metal-phthalocyanine. The prepared hollow carbon sphere has a carbon shell surface including fine pores, and the hollow carbon sphere may be impregnated with sulfur to prepare a carbon shell-sulfur composite and may be utilized as an anode material of a lithium-sulfur secondary battery. The carbon-sulfur composite material may improve extremely low electrical conductivity of sulfur, confine sulfur and lithium polysulfide originated from sulfur in the carbon shell in which fine pores are distributed to prevent lithium polysulfide having an extended chain structure from being dissolved in an electrolyte, minimize a shuttle reaction, reduce an overcharge amount between charging and discharging, and improve performance of a secondary battery.

Abstract: A volatile organogallium compound of formula(I), an azidodialkylgallium complexed with a hydrazine derivative, can form a GaN film having no nitrogen defects by a metal organic chemical vapor deposition(MOCVD): R1R2(N3)Ga.(R3HNNR4H)  (I) wherein, R1 and R2 are each independently C1-5 alkyl; and R3 and R4 are each independently hydrogen or C1-5 alkyl.