Abstract: A positive electrode active material for a lithium secondary battery has a mixture of microparticles having a predetermined average particle size (D50) and macroparticles having a larger average particle size (D50) than the microparticles. The microparticles have the average particle size (D50) of 1 to 10 ?m and are at least one selected from the group consisting of particles having a carbon material coating layer on all or part of a surface of primary macroparticles having an average particle size (D50) of 1 ?m or more, particles having a carbon material coating layer on all or part of a surface of secondary particles formed by agglomeration of the primary macroparticles, and a mixture thereof. The macroparticles are secondary particles having an average particle size (D50) of 5 to 20 ?m formed by agglomeration of primary microparticles having a smaller average particle size (D50) than the primary macroparticles.

Abstract: A positive electrode for a lithium secondary battery includes a positive electrode collector, a first positive electrode active material layer formed on the positive electrode collector and includes a first positive electrode active material, and a second positive electrode active material layer formed on the first positive electrode active material layer and includes a second positive electrode active material. The first positive electrode active material and the second positive electrode active material include a lithium nickel-cobalt-based oxide in which an amount of nickel among total metallic components excluding lithium is 80 atm % or more, the first positive electrode active material has a molar ratio of nickel to cobalt of 18 or more, and the second positive electrode active material has a molar ratio of nickel to cobalt of less than 18.

Abstract: An electrode includes an electrode active material, wherein the electrode active material layer includes an electrode active material, polyvinylidene fluoride, and a conductive agent, wherein the conductive agent includes a carbon nanotube structure in which 2 to 5,000 single-walled carbon nanotube units are bonded to each other, and the carbon nanotube structure is included in an amount of 0.01 wt % to 0.5 wt % in the electrode active material layer. A secondary battery including the same, and a method of preparing the electrode are also provided.

Abstract: A positive electrode active material for a lithium secondary battery comprising lithium transition metal oxide particles having a core-shell structure which includes a core portion and a shell portion disposed on a surface of the core portion. Wherein, the average crystallite size of the core portion is smaller than an average crystallite size of the shell portion and an amount of nickel among total transition metals included in the core portion and the shell portion is 80 atm % or more. A positive electrode active material, which suppresses decomposition of an electrolyte solution and occurrence of micro cracks of the positive electrode active material during charge and discharge by forming an average crystallite size of a core portion of the high-nickel positive electrode active material smaller than an average crystallite size of a shell portion, and a method of preparing the same.

Abstract: A focus ring and a method for manufacturing the same. The focus ring include a first ring made of a first material, a second ring covered by the first ring, wherein the second ring is made of a second material different from the first material, and a fastening member configured to couple the first ring to the second ring. The fastening member includes a through-part configured to pass through the second ring and a buried part buried in a lower portion of the first ring. The through-part has a first diameter, and the buried part has a second diameter greater than or equal to the first diameter.

Abstract: The present invention relates to a test socket heating module and a device test apparatus including the same, and more particularly, to a test socket heating module for performing a high-temperature test on a device, and a device test apparatus including the same. The present invention discloses a test socket heating module (200) including: a support plate (210) installed to be spaced apart a distance from a bottom surface of a test board (100) which is provided with one or more test sockets (20) for performing a test on a device (10) mounted on the test sockets; and one or more heater units (220) which are coupled to the support plate (210) between the test board (100) and the support plate (210), and heat the corresponding test sockets (20), respectively.

Abstract: Methods, devices, and systems are provided herein related to a connection management server connected to a signaling server, a push server, at least one home device, and at least two smart devices. The connection management server includes a connection management request receiver for receiving a video call connection request or a user switching request. A connection management request transmitter is also included for transmitting a connection state releasing request to the home device and the first smart device, for transmitting a video call push notification transmission request to the push server upon the video call connection request, and for transmitting a user switching push notification transmission request to the push server upon the user switching request. A group manager is also included for managing, in a group, smart device identity corresponding to a push notification sent from the push server.

Abstract: Methods, devices, and systems are provided herein related to a connection management server connected to a signaling server, a push server, at least one home device, and at least two smart devices. The connection management server includes a connection management request receiver for receiving a video call connection request or a user switching request. A connection management request transmitter is also included for transmitting a connection state releasing request to the home device and the first smart device, for transmitting a video call push notification transmission request to the push server upon the video call connection request, and for transmitting a user switching push notification transmission request to the push server upon the user switching request. A group manager is also included for managing, in a group, smart device identity corresponding to a push notification sent from the push server.

Abstract: A truss-reinforced spacer grid and a method of manufacturing the same are provided, in which truss members having a small diameter are woven to form a truss structure surrounded by an external plate, and the truss structure is joined to the external plate to thereby improve the strength of the mechanical structure. The truss-reinforced spacer grid includes a truss structure in which horizontal trusses formed by horizontally weaving a plurality of truss members are vertically disposed at regular intervals, and an external plate is joined with ends of the horizontal trusses and surrounds the truss structure.

Abstract: A spacer grid for nuclear fuel rods includes a plurality of unit spacer grids stacked one on top of another. Each unit spacer grid includes a plurality of unit spacer grid straps disposed at regular intervals in a row, and a plurality of fixing grid straps connected to respective opposite ends of the unit spacer grid straps so as to fix the unit spacer grid straps. Each unit spacer grid strap has convexities alternating with each other on opposite sides thereof at regular intervals, and at least one of the convexities has a diameter greater than the others. The unit spacer grids are rotated in one direction by a 90 or 180 degree angle when being stacked.

Abstract: An intermediate end plug assembly for a segmented fuel rod can stably support the fuel rod to the end of its cycle even if an interval between the fuel rods becomes narrow due to application of a dual-cooled fuel rod, and reduce excess vibration induced by flows of interior and exterior channels of the dual-cooled fuel rod for obtaining high burnup and output. To this end, the fuel rod has a segmented structure so as to make its length short. A lower intermediate end plug includes at least one channel hole, through which a coolant flows into an internal channel of the fuel rod, so that a possibility of causing departure from nuclear boiling ratio (DNBR) of the dual-cooled fuel rod is reduced.

Abstract: A spacer grid for nuclear fuel rods includes a plurality of unit spacer grids stacked one on top of another. Each unit spacer grid includes a plurality of unit spacer grid straps disposed at regular intervals in a row, and a plurality of fixing grid straps connected to respective opposite ends of the unit spacer grid straps so as to fix the unit spacer grid straps. Each unit spacer grid strap has convexities alternating with each other on opposite sides thereof at regular intervals, and at least one of the convexities has a diameter greater than the others. The unit spacer grids are rotated in one direction by a 90 or 180 degree angle when being stacked.

Abstract: A truss-reinforced spacer grid and a method of manufacturing the same are provided, in which truss members having a small diameter are woven to form a truss structure surrounded by an external plate, and the truss structure is joined to the external plate to thereby improve the strength of the mechanical structure. The truss-reinforced spacer grid includes a truss structure in which horizontal trusses formed by horizontally weaving a plurality of truss members are vertically disposed at regular intervals, and an external plate is joined with ends of the horizontal trusses and surrounds the truss structure.

Abstract: A porous plenum spacer is inserted into the plenum of a dual-cooled fuel rod having concentric inner and outer cladding tubes. The porous plenum spacer includes a hollow cylindrical body inserted into the annular space between the inner and outer cladding tubes. The hollow cylindrical body includes a plurality of through-holes formed in an outer circumference thereof or at least one groove formed in one of outer and inner circumferences thereof in a lengthwise direction. Pores formed by the through-holes or the grooves of the hollow cylindrical body of the porous plenum spacer are allowed to secure a space containing fission gas inevitably generated by a nuclear reaction.

Abstract: An intermediate end plug assembly for a segmented fuel rod can stably support the fuel rod to the end of its cycle even if an interval between the fuel rods becomes narrow due to application of a dual-cooled fuel rod, and reduce excess vibration induced by flows of interior and exterior channels of the dual-cooled fuel rod for obtaining high burnup and output. To this end, the fuel rod has a segmented structure so as to make its length short. A lower intermediate end plug includes at least one channel hole, through which a coolant flows into an internal channel of the fuel rod, so that a possibility of causing departure from nuclear boiling ratio (DNBR) of the dual-cooled fuel rod is reduced.