Abstract: An embodiment of the present specification provides a method for preparing a catalyst for preparing a carbon nanotube, comprising: (a) dissolving a main catalyst precursor, a support precursor, a cocatalyst precursor and a precipitation inhibitor in a solvent to prepare a precursor solution; and (b) pyrolyzing the precursor solution by spraying the precursor solution into a reactor, wherein a mole fraction of the precipitation inhibitor to the cocatalyst precursor is 0.1 to 1.5.

Abstract: An X-ray imaging apparatus includes an imaging device configured to capture a camera image of a target; a controller configured to stitch a plurality of X-ray images of respective divided regions of the target to generate one X-ray image of the target; and a display configured to display a settings window that provides a GUI for receiving a setting of an X-ray irradiation condition for the respective divided regions, and display the camera image in which positions of the respective divided regions are displayed.

Abstract: Provided are a chromium catalyst precursor, an ethylene oligomerization catalyst including the same, and a method of preparing an ethylene oligomer using the same. More particularly, a chromium catalyst precursor which may oligomerize ethylene with high activity and high selectivity in spite of not using methylaluminoxane (MAO) or modified-methylaluminoxane (MMAO), an oligomerization catalyst including the same, and a method of preparing an ethylene oligomer using the same are provided.

Abstract: Provided are a social network service system and a social network service method using the same. The social network service system includes a communication terminal configured to transmit an upload image that is photographed through a camera module or is included in the communication terminal together with information data for social networking, and a management server configured to receive the upload image and the information data for social networking from the communication terminal and to store the received upload image and the received information data for social networking, wherein the management server selects music information suitable for the upload image and stores the music information together with the upload image.

Abstract: Disclosed herein is a system for providing lyrics for a plurality of digital audio files. The system includes at least one terminal, a server, and a database server. The terminal selects a digital audio file among the digital audio files, and transmits tag information to receive lyrical data assigned to the selected digital audio file. The server retrieves the lyrical data, which is assigned to the selected digital audio file, using the tag information on the digital audio file transmitted from the terminal, and transmits the lyrical data to the terminal. The database server transmits the lyrical data in response to a request from the server and previously stores lyrical data in which lyrics are synchronized with digital audio files.