Abstract: A trisilylamine preparation apparatus includes: a reactor in which a trisilylamine synthesis reaction occurs; a reactant supply pipe for supplying reactants to the reactor; a trisilylamine discharge pipe for discharging trisilylamine from the reactor; a reactor heating means for heating the reaction space of the reactor; and a gaseous by-product discharge pipe for discharging a gaseous by-product from the reactor. The reaction space of the reactor is maintained at a temperature that is lower than the decomposition temperature of a reaction by-product generated during the synthesis reaction, the reactor heating means heats the reaction space of the reactor to a temperature that is higher than or equal to the decomposition temperature after trisilylamine is discharged through the trisilylamine discharge pipe, and the gaseous by-product discharge pipe discharges a gaseous by-product comprising a pyrolysate of the reaction by-product, generated through pyrolysis by means of the reactor heating means.

Abstract: An image projection apparatus according to an embodiment of the present invention senses the distance to an image projection area to which an image is projected, and determines an image projection state including a state of at least one of the image projection area and a space between the image projection apparatus and the image projection area, on the basis of the sensed distance. The image projection apparatus projects an image onto the image projection area on the basis of the determined image projection state.

Abstract: An image projection apparatus according to an embodiment of the present invention senses the distance to an image projection area to which an image is projected, and determines an image projection state including a state of at least one of the image projection area and a space between the image projection apparatus and the image projection area, on the basis of the sensed distance. The image projection apparatus projects an image onto the image projection area on the basis of the determined image projection state.

Abstract: The present invention relates to a system and method for providing prepaid telecommunication services. More particularly, prepaid telephone calls can be made by users without entering any access code, if such calls are made from telephone numbers previously registered in the telecommunication system in connection with valid access codes. Prepaid telephone calls can also be made from non-registered telephone numbers after providing the telecommunication system with a valid access code.

Abstract: The present invention relates to a system and method for providing prepaid telecommunication services. More particularly, prepaid telephone calls can be made by users without entering any access code, if such calls are made from telephone numbers previously registered in the telecommunication system in connection with valid access codes. Prepaid telephone calls can also be made from non-registered telephone numbers after providing the telecommunication system with a valid access code.

Abstract: The present invention relates to a system and method for providing prepaid telecommunication services. More particularly, prepaid telephone calls can be made by users without entering any access code, if such calls are made from telephone numbers previously registered in the telecommunication system in connection with valid access codes. Prepaid telephone calls can also be made From non-registered telephone numbers after providing the telecommunication system with a valid access code.

Abstract: The present invention relates to a system and method for providing prepaid telecommunication services. More particularly, prepaid telephone calls can be made by users without entering any access code, if such calls are made from telephone numbers previously registered in the telecommunication system in connection with valid access codes. Prepaid telephone calls can also be made from non-registered telephone numbers after providing the telecommunication system with a valid access code.

Abstract: The present invention relates to a system and method for providing prepaid telecommunication services. More particularly, prepaid telephone calls can be made by users without entering any access code, if such calls are made from telephone numbers previously registered in the telecommunication system in connection with valid access codes. Prepaid telephone calls can also be made from non-registered telephone numbers after providing the telecommunication system with a valid access code.

Abstract: The present invention relates to a system and method for providing prepaid telecommunication services. More particularly, prepaid telephone calls can be made by users without entering any access code, if such calls are made from telephone numbers previously registered in the telecommunication system in connection with valid access codes. Prepaid telephone calls can also be made from non-registered telephone numbers after providing the telecommunication system with a valid access code.

Abstract: The present invention relates to a system and method for providing prepaid telecommunication services. More particularly, prepaid telephone calls can be made by users without entering any access code, if such calls are made from telephone numbers previously registered in the telecommunication system in connection with valid access codes. Prepaid telephone calls can also be made from non-registered telephone numbers after providing the telecommunication system with a valid access code.