Korea Kumho Petrochemical Co., Ltd.

Sungkyunkwan University

Kongju National University Industry-University Cooperation Foundation

Dong-Hwan Kim

Sang-woo Kim

Sang-Hyo Ryu

Yong-jun Lee

Sung-Ruyl Kwon

Min-ha Kim

Min-jun Kim

Kang-Seon Hwang

Jung-yoon Lee

Kil-hee Kim

Hyung-Song Lee

Hyeong-gook Kim

In a device for evaluating torsional structural performance of girder according to an embodiment of the present disclosure, a guide unit of a support member formed in a shape of an arc having its center that matches a shear center of the girder rotatably supports a rotating member, so that the shear center of the girder matches a center of torsion during clockwise or counterclockwise rotation of the rotating member, thereby measuring an accurate angle of twist and preventing an incident in which the rotating member escapes due to separation of a component by a rotational force.

Device for evaluating torsional structural performance of girder

The present invention relates to a method for evaluating an initial capacity of secondary batteries and, more specifically, to a method for evaluating an initial capacity of secondary batteries that involves mathematical operation of specific internal resistance components obtained from an equivalent circuit model of an impedance spectrum measured for a short time period instead of using direct discharge characteristics, thereby allowing selection of batteries having a different initial discharge characteristic.

Method for evaluating capacity of secondary battery using mathematical calculation of specific resistance components of equivalent circuit model fitted from impedance spectrum

Provided is a method of preparing a cathode material for lithium ion cell, which is designed to have the cycle characteristic enhanced and high initial discharge capacity, by synthesizing LiMn.sub.2 O.sub.4 powder having a stable spinel structure, vigorously agitating the powder in an aqueous solution of Li and Ni ions, dispersing the solution through a supersonic wave treatment, filtering it so as for the powder to adsorb the ions, and performing a heat treatment for doping the ions.

Method of preparing cathode material for lithium ion cell

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Daejeon, South Korea

Dong-Hwan Kim