• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.266-272
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• 1997

In order to investigate the compression and decompression properties of cucumber, radish, garlic, ginger and potato, edible parts of samples were prepared to size of ${\Phi}\;5\;mm{\times}H\;5\;mm$, and force deformation relationship during application and removal of force were observed. Compositions of sample and cell characteristics were measured, and correlations between them were investigated. Deformation rate was large in initial stage of compression and decreased afterward, but the reverse trends were observed in the decompression. The time and deformation to 9 N were large of 5.30 sec and 1.344 mm in potato, and small of 4.62 sec and 0.896 mm in garlic, respectively. Force(y)-deformation(x) curve between compression and decompression were clearly showed hysteresis loop and relationship of x and y were as follows: y=esp (a+b log(x)). The maximum work was $3.888{\sim}5.099{\times}10^{-3}\;J$ for potato in compression and $2.09{\times}10^{-3}\;J$ for garlic in decompression. Irrecoverable work were large as $77{\sim}96%$ in cucumber, radish and potato, and small as $36{\sim}42%$ in garlic. Compression deformation were large as $1.016{\sim}1.344\;mm$ in potato, and small as $0.656{\sim}0.896\;mm$ in garlic. Degree of elasticity were large as $0.756{\sim}0.777$ in garlic, and small as $0.301{\sim}0.465$ in radish and potato. Compression and decompression characteristic values were showed high correlation with moisture, viscosity of juice, ceil size, density and regularity.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.8
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• pp.757-764
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• 2015

Mathematical modeling of focal plane compensation device in the small earth-observation satellite camera has been conducted experimently for compensation of micro-vibration disturbance. The PZT actuators are used as control actuators for compensation device. It is quite difficult to build up mathematical model because of hysteresis characteristic of PZT actuators. Therefore, the compensation device system is assumed as a $2^{nd}$ order linear system and modeled by using MATLAB System Identification Toolbox. It has been found that four linear models of compensation device are needed to meet 10% error in the input frequency range of 0~50Hz. These models describe accurately the dynamics of compensation device in the 4 divided domains of the input frequency range of 0~50Hz, respectively. Micro-vibration disturbance can be compensated by feedback control strategy of switching four models appropriately according to the input frequency.

• Structural Engineering and Mechanics
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• v.83 no.3
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• pp.305-326
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• 2022

To realize the recycling utilization of waste concrete and alleviate the shortage of resources, 11 specimens of steel reinforced recycled concrete (SRRC) filled circular steel tube columns were designed and manufactured in this study, and the cyclic loading tests on the specimens of columns were also carried out respectively. The hysteretic curves, skeleton curves and performance indicators of columns were obtained and analysed in detail. Besides, the finite element model of columns was established through OpenSees software, which considered the adverse effect of recycled coarse aggregate (RA) replacement rates and the constraint effect of circular steel tube on internal RAC. The numerical calculation curves of columns are in good agreement with the experimental curves, which shows that the numerical model is relatively reasonable. On this basis, a series of nonlinear parameters analysis on the hysteretic behaviors of columns were also investigated. The results are as follows: When the replacement rates of RA increases from 0 to 100%, the peak loads of columns decreases by 7.78% and the ductility decreases slightly. With the increase of axial compression ratio, the bearing capacity of columns increases first and then decreases, but the ductility of columns decreases rapidly. Increasing the wall thickness of circular steel tube is very profitable to improve the bearing capacity and ductility of columns. When the section steel ratio increases from 5.54% to 9.99%, although the bearing capacity of columns is improved, it has no obvious contribution to improve the ductility of columns. With the decrease of shear span ratio, the bearing capacity of columns increases obviously, but the ductility decreases, and the failure mode of columns develops into brittle shear failure. Therefore, in the engineering design of columns, the situation of small shear span ratio (i.e., short columns) should be avoided as far as possible. Based on this, the calculation model on the skeleton curves of columns was established by the theoretical analysis and fitting method, so as to determine the main characteristic points in the model. The effectiveness of skeleton curve model is verified by comparing with the test skeleton curves.