• Structural Engineering and Mechanics
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• v.78 no.5
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• pp.637-649
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• 2021

Great efforts have been conducted to investigate the seismic performances of the arch and rectangular underground structures, however, the differences between seismic responses of these two types of underground structures, especially the vault radian influencing the seismic responses of arch structures are not clarified. This paper presents a detailed numerical investigation on the seismic responses of arch underground structures with different vault radians, and aims to illustrate the rule that vault radian affects the seismic responses of underground structures. Five arch underground structures are built for nonlinear soil-structure interaction analysis. The internal forces of the structural components of the underground structures only under gravity are discussed detailedly, and an optimum vault radian for perfect load-carrying functionality of arch underground structures is suggested. Then the structures are analyzed under seven scaled ground motions, amounting to a total of 35 dynamic calculations. The numerical results show that the vault radian can have beneficial effects on the seismic response of the arch structure, compared to the rectangular underground structures, causing the central columns to suffer smaller axial force and horizontal deformation. The conclusions provide some directive suggestions for the seismic design of the arch underground structures.

• Korean Journal of Optics and Photonics
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• v.10 no.3
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• pp.259-264
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• 1999

The relationship is derived for color CRT display system between the spectral radian existence emitted and digital inputs. The amount of spectral radiant existence depends on the characteristics of the video board, electric circuits, and CRT as well as digital inputs. Especially, the function of this relationship changes as the amplifier gain and offset voltage of electric circuits. In this study, we set the test display system on the optimum state which satisfies gun independence characteristics by using the contrast and the brightness controls of display. Temporal stability, special uniformity, and color distinction of CRT display system are evaluated at the optimum state. Also contrasts in dark room and illuminated room are compared.