Abstract: Provided are a method for preparing a polyetherketoneketone and a polyetherketoneketone prepared thereby, wherein, at the time of a polymerization reaction, nitrogen gas is blown into a liquid reaction medium while stirring, thereby quickly removing hydrochloric acid, which is a by-product generated during the reaction, and preventing aggregation of resin particles, thus suppressing the generation of scales.

Abstract: The present disclosure relates to an organic electroluminescent device. The organic electroluminescent device of the present disclosure shows high luminous efficiency and good lifespan by comprising a specific combination of the plural kinds of host compounds and a specific hole transport compound.

Abstract: The present disclosure relates to a microorganism detection apparatus using a dielectrophoresis (DEP) force.

Abstract: Disclosed is a method for determining precoding matrix based on an open-loop MIMO scheme, which can enhance a diversity gain at a static communication environment or a low-mobility communication environment. The method for determining precoding matrix applies a first precoding matrix to downstream data to transmit the downstream data through a plurality of antennas, the first precoding matrix being selected from a codebook which comprises a plurality of precoding matrixes, and changes the first precoding matrix to a second precoding matrix per predetermined period, and applying the second precoding matrix to the downstream data to transmit the downstream data through the antennas. The second precoding matrix is a precoding matrix corresponding to an index which has been shifted by a certain value from an index of the first precoding matrix in a direction where an index of a precoding matrix increases, in the codebook.

Abstract: Disclosed is a method for determining precoding matrix based on an open-loop MIMO scheme, which can enhance a diversity gain at a static communication environment or a low-mobility communication environment. The method for determining precoding matrix applies a first precoding matrix to downstream data to transmit the downstream data through a plurality of antennas, the first precoding matrix being selected from a codebook which comprises a plurality of precoding matrixes, and changes the first precoding matrix to a second precoding matrix per predetermined period, and applying the second precoding matrix to the downstream data to transmit the downstream data through the antennas.