Abstract: The present disclosure relates to a high energy density lithium secondary battery having significantly improved high-temperature storage characteristics and lifespan characteristics, which are problematic when a silicon-based negative electrode active material is applied. Specifically, a lithium secondary battery according to an exemplary embodiment includes a positive electrode; a negative electrode facing the positive electrode and including a silicon-based negative electrode active material; and a non-aqueous electrolyte containing a non-aqueous organic solvent including a di-fluoro-based organic solvent and a lithium salt, wherein a content of the di-fluoro-based organic solvent is 5 to 20 vol % with respect to a total volume of the non-aqueous organic solvent.

Abstract: An anode for a secondary battery includes an anode current collector, a first anode active material layer disposed on at least one surface of the anode current collector and including a first anode active material that includes a first silicon composite oxide, and a second anode active material layer disposed on the first anode active material layer and including a second anode active material that includes a second silicon composite oxide. Each of the first silicon composite oxide and the second silicon composite oxide includes a metal. A BET specific surface area of each of the first silicon composite oxide and the second silicon composite oxide is in a range from 2.0 m2/g to 6.5 m2/g.

Abstract: Provided is a method of measuring eccentricity of a blind via hole formed in a printed circuit board including an inner-layer board and an outer-layer board that are bonded by thermocompression bonding. The method includes acquiring, by a microscope camera, an image by photographing a marker which is formed on a surface of the outer-layer board and a blind via hole which is exposed upward through a marker hole formed in a center of the marker with a microscope camera, and measuring, by computing equipment connected to the microscope camera, eccentricity indicating a separation distance and a separation direction from central coordinates of the marker hole to central coordinates of the blind via hole using a distance between an end point of the marker hole and an end point of the blind via hole which are included in the image.

Abstract: Provided is a method of measuring eccentricity of a blind via hole formed in a printed circuit board including an inner-layer board and an outer-layer board that are bonded by thermocompression bonding. The method includes acquiring, by a microscope camera, an image by photographing a marker which is formed on a surface of the outer-layer board and a blind via hole which is exposed upward through a marker hole formed in a center of the marker with a microscope camera, and measuring, by computing equipment connected to the microscope camera, eccentricity indicating a separation distance and a separation direction from central coordinates of the marker hole to central coordinates of the blind via hole using a distance between an end point of the marker hole and an end point of the blind via hole which are included in the image.

Abstract: Provided is a method of measuring uniformity of a signal line pattern formed on a printed circuit board.