• Steel and Composite Structures
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• v.48 no.4
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• pp.461-474
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• 2023

Concrete-filled steel tubes are among the most efficient compressive structural members because the strength of the concrete is enhanced given that the surrounding steel tube confines the concrete laterally and the steel tube is restrained with regard to inward deformation due to the concrete existing inside. Accurate estimations of the ultimate compressive strength of CFT are important for efficient designs of CFT members. In this study, an analytical procedure that directly formulates the interaction between the concrete and steel tube by considering the nonlinear Poisson effect and stress-strain curve of the concrete including the confinement effect is proposed. The failure stress of concrete and von-Mises failure yield criterion of steel were used to consider multi-dimensional stresses. To verify the prediction capabilities of the proposed analytical procedure, 99 circular CFT experimental data instances from other studies were used for a comparison with AISC, Eurocode 4, and other researchers' predictions. From the comparison, it was revealed that the proposed procedure more accurately predicted the ultimate compressive strength of a circular CFT regardless of the range of the design variables, in this case the concrete compressive strength, yield strength of the steel tube and diameter relative to the thickness ratio of the tube.

• Journal of Radiation Protection and Research
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• v.32 no.4
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• pp.134-139
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• 2007

In order to find out the Radioprotective effect of algin-oligosaccharide(AOS), this study, with a mouse of which whole frame irradiated by 3 Gy radiation once, measured caspase-3 and caspase-9 amid cell signaling connected to apoptosis in order to observe cell activation. In Caspase-3 and Caspase-9 test for observing cell activation, both of Caspase-3 and Caspase-9 showed highly increased O.D. value in the irradiation control group, while the whole groups treated with algin-oligosaccharide before or after irradiation indicated lower O.D. value than the irradiation control group, especially showed big difference in 7 day's treatment group of before irradiation (P<0.001). It confirmed that Caspase generation was restrained in AOS treatment group. Consequently, this study inquired into the fact that algin-oligosaccharide with superior antioxidant activity performed radiation protection by inducing restraint of Caspase generation and confirmed that natural product with less chemical toxicity was able to be applied as radioprotector.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.4
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• pp.772-781
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• 1998

The purpose of this study was to assess the sedative effect of intranasal spray with midazolam for management of the uncooperative 20 children aged from 24 months to 92 months who required extensive treatment. The patients were given randomly a dose of 0.2mg/kg of intranasal placebo, intranasal spray with midazolam, and intranasal drop with midazolam. All the children were restrained in a pediwrap and were monitored with pulse oximeter for assessing the pulse rate and peripheral oxygen saturation. According to Fukuta's behavior rating scale, behavior was checked for evaluation of the clinical sedative effect. The obtained results were as follows: 1. Behavior score of intranasal spray with midazolam was lower than intranasal drop with midazolam(P<0.01). 2. Pulse rate was a significant change as a function of dental procedure(P<0.001), however the peripheral oxygen saturation was not influenced significantly by either adiministration route of drug or dental procedure. Clinically, intranasal spray with midazolam were safe and effective sedation in young children undergoing pediatric dental procedures.

• The Journal of Pediatrics of Korean Medicine
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• v.29 no.2
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• pp.1-15
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• 2015

Objectives In the theory of Korean Medicine, Cicadae Periostracum (CP) has been used to treat skin diseases such as inflammatory dermatitis, tetanus and pruritus. CP can reduce heat and disperse wind. In prior studies, anti-allergic effect and anti-inflammatory effect of CP were reported. However, there has been no report regarding the correlation of CP and allergic contact dermatitis (ACD). This study was performed to show the effects of CP in ACD induced by 2,4-dinitrochlorobenzene (DNCB) in mice. Methods In this experiment, the effects of CP on biological changes were measured, such as changes in ear and spleen weight, ear and dorsum skin thickness, clinical aspect on the dorsum skin and histological changes. The effect of proliferation rate of splenocytes was also investigated in vitro and vivo study. Results In results, CP application (CPA) group and CP application and administration (CPAA) group were significantly restrained in ear weight gain and increase in ear and dorsum skin thickness compared to the control group. In addition, CPA and CPAA group showed diminished erythema, desquamation, bloodstain, and marks. Also, the histological assessment showed that CP treatement diminished thickness of epidermis, hyperkeratosis, pigmentation and parakeratosis. Conclusions In conclusion, these data suggest that CP can decrease symptoms of ACD.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.325-330
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• 2008

In this study 3- and 6-story flat plate structures designed only for gravity load are retrofitted with steel plates and braces and their seismic performances are evaluated to verify the effect of seismic retrofit. According to the analysis results obtained from nonlinear static analysis both the strength and stiffness are significantly enhanced as a result of the seismic retrofit. When buckling-restrained braces are used instead of conventional braces, the structures show more ductile behavior, especially in the 3-story structure.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.6
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• pp.1496-1502
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• 1994

The influences of spring position and spring stiffness on the critical force of a cantilevered beam subjected to a follower force are investigated. The spring attatched to the beam is assumed to be a translational one and can be located at arbitrary positions of the beam as it has not been assumed so far. The effects of transeverse shear deformation and rotary intertia of the beam are also included in this analysis. The charateristic equation for the system is derived and a finite element model of the beam using local coordinates is formulated through extended Hamilton's principle. It is found that when the spring is located at position less than that of 0.5L, the flutter type instability only exists. It is shown that the spring position approaches to the free end of the beam from its midpoint, instability type is changed from flutter to divergence through the jump phenomina according to the increase of spring stiffness.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.2
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• pp.176-184
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• 1996

The paper describes the vibration characteristics of the mechanical system consisting of a uniform Timoshenko beam with a guided mass and an elastic spring support. The free end of the beam does not rotate and the spring attatched to the guided mass is elastically restrained against translation. The guided mass is assumed to be a rigid body having a finite size, but not a mass point as it has been assumed so far. The effect of magnitudes, rotary inertia and the size of the guided mass on the vibration characteristics is fully investigated by the numerical simulation using FEM and experiment. In order to verify the eigenvalue sensitivity for considered system, comparison exact solutions with FEM is conducted, and a good agreement between two solutions is also highlighted.

• Journal of the Korean Society for Heat Treatment
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• v.3 no.1
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• pp.8-16
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• 1990

Effects of thermomechanical treatments(TMT) on the microstructures and mechanical properties in Al-2.27%, Li-1.28%, Cu-0.63%, Mg-0.12%, Zr alloy were investigated. The TMT process improved the tensile strength. Growth of ${\delta}^{\prime}$, S' and $T_1$ phases was restrained by TMT processes while the density of ${\delta}^{\prime}$, S' and $T_1$ phases was increased by TMT processes. The TMT treated specimens tend to fail in inter-subboundary mode. The increases of strength by the T-HA processes were compared to those of the T-AHA processes.

• Korean Journal of Pharmacognosy
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• v.7 no.2
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• pp.111-114
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• 1976

This study was aimed to investigate the effects of Ginseng ethanol extract on Diabetes induced by alloxan in comparison with that of insulin. The blood sugar, blood urea nitrogen, glutamic oxaloacetic transaminase and cholesterol were measured by spectrophotometry. The results were obtained as follows. 1. Ethanol extract of Ginseng increased the blood sugar level in normal rats. 2. Ethanol extract of Ginseng restrained the increase of blood sugar in diabetes induced by alloxan. 3. Ethanol extract of Ginseng acted to oppose a rapid decrease of blood sugar by insulin. 4. Blood urea nitrogen, glutamic oxaloacetic transaminase and cholesterol level in blood were not affected by Ginseng.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.657-662
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• 2000

This paper presents the results from experimental study that investigated to explore the load transfer characteristics of post-tensioning anchorage zones. The experimental program investigated the primary variables which affect the ultimate load, lateral strains and crack width: concrete compressive strength, details of reinforcement and shape of anchorage. Through this research, it was found that the governing factor of the ultimate load was not compressive cylinder strength but tensile splitting strength. Ultimate load was increased and lateral strain was decreased as the ratio of spiral increased because the lateral expansion of th concrete inside the spiral was restrained by the spiral. Furthermore, the shape of anchorage which can diminish the wedge effect of anchorage and disperse the anchorage force in various depths was more effective.