Abstract: A positive electrode active material including a first lithium composite oxide particle including a secondary particle formed by aggregation of one or more primary particles, and a coating oxide occupying at least a part of at least one of surfaces of the secondary particle, grain boundaries between the primary particles, or surfaces of the primary particles, the positive electrode active material satisfying an equation of 1.3?a/b?3.0, wherein a represents a max peak intensity at 2theta=44.75° to 44.80° and b represents a max peak intensity at 2theta=45.3° to 45.6° in X-ray diffraction (XRD) analysis using Cu K? radiation.

Abstract: A memory system may include: a memory device configured to store first training information and second training information representing different training patterns; and a memory controller configured to: perform a first training operation on the memory device based on the first training information, and perform, when a result of the first training operation is out of a predetermined range, a second training operation on the memory device plural times based on the second training information.

Abstract: Disclosed is a bulletproof panel that can replace glass of a vehicle, an elevator, a meeting room, a ticket booth, or the like. The bulletproof panel includes a base layer, a reinforcing layer provided on each of opposite sides of the base layer, and an adhesive layer provided on the base layer and each of the reinforcing layers and made of a UV-curable urethane resin. The bulletproof panel is characterized in that when the panel is impacted by a bullet, the base layer breaks and absorbs a rotational force of the bullet, while the reinforcing layers provided on respective opposite sides of the base layer suppress broken pieces of the base layer from scattering. Thus, the bulletproof panel can exhibit an excellent bulletproof effect because the bullet is fixed in the base layer and does not penetrate therethrough, while preventing broken pieces generated by the bullet from scattering.