• Advances in nano research
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• v.8 no.4
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• pp.323-333
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• 2020

In recent years, there has been an upsurge for the usage of buckling restrained braces (BRB) rather than ordinary braces, as they have evidently performed better. If the overall brace buckling is ignored, BRBs are proven to have higher energy absorption capacity and flexibility. This article aims to deliberate an economically efficient yet adequate type of all-steel BRB, comprised of the main components as in traditional ones, such as : (1) a steel core that holds all axial forces and (2) a steel restrainer tube that hinders buckling to occurr in the core; there is a more practical detailing in the BRB system due to the elimination of a filling mortar. An investigation has been conducted for the proposed rectangular-tube core BRB and it is hysteric behavioral results have been compared to previous researches conducted on a structure containing a similar plate core profile that has the same cross-sectional area in its core. A loss of strength is known to occur in the BRB when the limiting condition of local buckling is not satisfied, thus causing instability. This typically occurs when the thickness of the restrainer tube's wall is smaller than the cross-sectional area of the core plate or its width. In this study, a parametric investigation for BRBs with different formations has been performed to verify the effect of the design parameters such as different core section profiles, restraining member width to thickness ratio and relative cross-sectional area of the core to restrainer, on buckling load evaluation. The proposed BRB investigation results have also been presented and compared to past BRB researches with a plate profile as the core section, and the advantages and disadvantages of this configuration have been discussed, and it is concluded that BRBs with tubular core section exhibit a better seismic performance than the ones with a plate core profile.

• Journal of Haehwa Medicine
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• v.10 no.1
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• pp.489-494
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• 2001

To determine the preventive effect of Samulanshintang (SA) on stress, we investigated the physiological change of rats which were applied immobilization stress. For immobilization stress, rats were placed in restrainer for 12 hours a day for 3 days. During application of stress, body weight of rats was measured. After sacrifice, 4 organs were taken for measurement of organ weight. Brain was homogenated and its catecholamine and serotonin contents were measured with HPLC. In our study, stress mainly induced increase of concentration of neurotransmitters in brain without other significant physical change of rats. SA inhibited stress induced changes of neurotransmitter content in brain.

• Journal of Society of Preventive Korean Medicine
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• v.5 no.2
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• pp.114-121
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• 2001

To elucidate the preventive effect of oriental medicine Gami-Ondamtang(GO) on stress, we investigated the physiological change of rats which were applied immobilization stress. For immobilization stress, rats were placed in restrainer for 12 hours a day for 3 days. During application of stress, body weight of rats was measured. After sacrifice, 8 organs were taken for measurement of organ weight. Brain was sectioned into 4 parts that are Frontal Cortex, Corpus Striatum, Hypothalamus and Hippocampus. Each part was homogenated and its catecholamine and serotonin contents were measured with HPLC. In our study, stress mainly induced increase of concentration of neurotransmitters in brain without other significant physical change of rats. GO inhibited stress induced changes of neurotransmitter content in brain.

• Environmental Analysis Health and Toxicology
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• v.14 no.3
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• pp.127-133
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• 1999

To elucidate the preventive effect of oriental medicine Gungchi -hwadamsun (GH) on stress, we investigated the physiological change of rats which were applied immobilization stress. For immobilization stress, rats were placed in restrainer for 12 hours a day for 3 days. During application of stress, body weight of rats was measured. After sacrifice, 8 organs were taken for measurement of organ weight. Brain was sectioned into 4 parts that are Frontal Cortex, Corpus Striatum, Hypothalamus and Hippocampus. Each part was homogenated and its catecholamine and serotonin contents were measured with HPLC. In our study, stress mainly induced increase of concentration of neurotransmitters in brain, but had mild effect on other physical function of rats. GH inhibited stress induced changes of neurotransmitter content in brain.

• Steel and Composite Structures
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• v.13 no.5
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• pp.423-436
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• 2012

In this study total of six buckling-restrained braces (BRBs) were manufactured using a square steel rod as a load-resisting core member and a hollow steel tube as restrainer to prevent global buckling of the core. The gap between the core and the tube was filled with steel rods as filler material. The performances of the proposed BRB from uniaxial and subassemblage tests were compared with those of the specimens filled with mortar. The test results showed that the performance of the BRB with discontinuous steel rods as filler material was not satisfactory, whereas the BRBs with continuous steel rods as filler material showed good performance when the external tubes were strong enough against buckling. It was observed that the buckling strength of the external tube of the BRBs filled with steel rods needs to be at least twice as high as that of the BRBs filled with mortar to ensure high cumulative plastic deformation of the BRB.

• Environmental Analysis Health and Toxicology
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• v.13 no.3_4
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• pp.143-149
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• 1998

To elucidate the preventive effect of Danchisoyosan (DS) on stress, we investigated the physiological change of rats which were applied immobilization stress. For immobilization stress, rats were placed in restrainer for 12 hours a day for 3 days. During application of stress, body weight of rats was measured. After sacrifice, 8 organs were taken for measurement of organ weight. Brain was sectioned into 4 parts that are Frontal Cortex, Corpus Striatum, Hypothalamus and Hippocampus. Each part was homogenated and its catecholamine and serotonin contents were measured with HPLC. In our study, stress mainly induced increase of concentration of neurotransmitters in brain without other significant physical change of rats. DS inhibited stress induced changes of neurotransmitter content in brain.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.5
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• pp.23-32
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• 2007

The goal of this study is to perform several bending tests on a shape memory alloy bar and to analyze the characteristics of the bending behavior. The other goal is to verify the seismic performance of an SMA bar bending application. Single and double bending tests were conducted with varying loading speeds and maximum displacement. The loading and the unloading stiffness were estimated from the force-displacement curves and the equivalent damping ratio of each test was also assessed. In single bending, the SMA bar showed the stiffness hardening after the displacement of 32 mm. It is assumed that this phenomenon is due to the stress-induced-martensite hardening. The increasing loading speed did not influence on the stiffness of the single bending SMA bar. The stiffness of the double bending bar is about 5 times of that of the single bending. This study introduced a seismic application of SMA bending bars as seismic restrainers for bridges and showed its practicality. SMA bars in bending are used for seismic restrainers in a three-span-simply-supported bridge. They showed the effectiveness to reduce the responses of the bridge and the applicability for a seismic restrainer. The significance of this study is to provide basic knowledge of SMA bending and its seismic applications.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.4
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• pp.352-357
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• 2012

The ground resonance instability of a helicopter with bearingless main rotor hub were investigated. The ground resonance instability is caused by an interaction between the blade lag motion and hub inplane motion. This instability occurs when the helicopter is on the ground and is important for soft-inplane rotors where the rotating lag mode frequency is less than the rotor rotational speed. For the analysis, the bearingless rotor was composed of blades, flexbeam, torque tube, damper, shear restrainer, and pitch links. The fuselage was modeled as a mass-damper-spring system having natural frequencies in roll and pitch motions. The rotor-fuselage coupling equations are derived in non-rotating frame to consider the rotor and fuselage equations in the same frame. The ground resonance instabilities for three cases where are without lead-lag damper and fuselage damping, with lead-lag damper and without fuselage damping, and finally with lead-lag damper and fuselage damping. There is no ground resonance instability in the only rotor-fuselage configuration with lead-lag damper and fuselage damping.

• Journal of the Korean Applied Science and Technology
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• v.28 no.3
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• pp.259-266
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• 2011

Caffeic acid is a kind of phytochemicals occurred in coffee, which is worked as a carcinogenesis restrainer and antioxidants on the human body. In this study, as one type of caffeic acid derivatives, methoxypolyethylene glycol caffeate(MPC) was synthesized by the esterification between caffeic acid and methoxypolyethylene glycol with N,N'-dicyclohexyl carbodiimide, 4-dimethylamino pyridine. The synthesized product was confirmed by using FT-IR and $^1H$-NMR, thin-layer chromatography. And these compound was investigated as antioxidant, Tyrosinase hindrance and skin moisturizers. In the free radical scavenging study, antioxidant effect of MPC was averagely high than the red ginseng extract that be used as a natural antioxidants. The result of Tyrosinase anti-activity test was better than embryo bud of rice extract at low concentration. At the iNOS anti-activity tested by using Raw 264.7 cell, and confirmed anti-inflammatory function. For the MPC handled with sodium lauryl sulfate, was tested for the skin moisture content and skin moisture loss.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.905-910
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• 2004

Vibration characteristics of the FIV test loop for the Flow-Induced Vibration(FIV) study of a PWR partial(5x5) fuel assembly are investigated by the Finite Element(FE) analysis and the modal test. For the FE analysis, 3-D beam element is used for the pipes and the test section and mass element used for the valves and flanges. The 'U' restrainer stiffness determined by numerical simulation is used for the FE model. The result of the FE analysis is compared with that of the modal test. The higher mode similarity between the test and analysis is observed in a few low modes. After that, the mode similarity reduce as the mode goes high. It is concluded that the first to the third vibration modes are observed at the lower parts of the 6 inches restoring line, followed by a local mode at the test section, and the natural frequencies of the modes are 22.4 Hz, 26.0 Hz, 27.5 Hz and 31.4 Hz.