• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.3
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• pp.87-95
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• 2020

As an experimental study on the corrosion behavior of steel materials to which ATMS method using EIS was applied in concrete, immersion of Ca(OH)₂ saturated aqueous solution and NaCl aqueous solution simulating the environment inside concrete The corrosion behavior was tested. The equivalent circuit was derived through the analysis of the Nyquist plot, and the interfacial resistance and the polarization resistance of the Ca(OH)₂ aqueous solution were compared, and Al ATMS was the best interfacial resistance and Zn ATMS was the best polarization resistance. After burying ATMS steel material of cement mortar, the initial immersion impedance measurement value was the highest in the Zn ATMS test body in the impedance measurement by the immersion time by immersing it in the NaCl aqueous solution. Al ATMS test piece has the highest impedance and is highly reliable. This is because Al, which has a high ionization tendency, is continuously oxidized in a strong alkaline environment to form a film and protect the steel from permeation of chlorine ions.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.73-83
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• 2023

This study is a descriptive survey to develop a gamification e-learning class based on self-determination theory and to check its effectiveness. The data collection period was from March 1 to June 15, 2023, and 59 students at G University in G Metropolitan City were surveyed on class participation, learning immersion, and teaching presence before and after the course. IBM SPSS/Win 26.0 was used to analyze the collected data, and descriptive statistics, analysis of variance (ANOVA), and analysis of covariance (ANCOVA) were conducted. The results showed that the self-determination-based gamification class significantly improved students' class participation, learning engagement, and teaching presence (p<.05). An analysis of covariance (ANCOVA) was conducted to determine whether the general characteristics of the participants affected the results of the post-test, and gender affected the post-test results of learning engagement, with an effect of 7.9%. Based on the results of this study, it can be seen that self-determination-based gamification e-learning class is effective in improving learners' class participation, learning engagement, and teaching presence. As the demand for e-learning in universities is expanding, self-determination-based gamification e-learning classes should be developed in various fields of liberal arts and majors.

• Natural Product Sciences
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• v.9 no.4
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• pp.256-259
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• 2003

The pet ether extract of Caesalpinia pulcherrima, leaves was studied for its antinociceptive, anti-inflammatory and antipyretic property. The extract at doses of 50 and 200 mg/kg, p.o., significantly (p<0.05) reduced the number of writhing induced by acetic acid and inhibited the late phase (20-30 min) in formalin test in mice. The extract failed to increase the pain threshold level in tail immersion test in mice. In carrageenan induced paw edema in rats and in acetic acid induced increase in vascular permeability test in mice, the extract (50-600 mg/kg, p.o.) failed to produce any significant activity. While in cotton pellet granuloma test, the extract at doses of 200 and 600 mg/kg (p.o.) significantly (p<0.05) reduced the granuloma formation and was comparable to reference drug, dexamethasone. In ethylpheylpropiolate ear edema test 0.5 mg and 1 mg/ear application of extract significantly (p<0.05) inhibited ear edema. In yeast induced hyperthermia in rats, the extract did not produce any reduction in temperature. The results suggest that the extract acts peripherally to produce analgesic action and anti-inflammatory activity through steroidal mechanism.

• Natural Product Sciences
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• v.19 no.4
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• pp.311-315
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• 2013

Ribes fasciculatum (Saxifragaceae) has been widely used as a traditional medicine for the treatment of cough, antidote, cold, lacquer poison, and sore throat. In the present study, we evaluated the anti-nociceptive effects of ethyl acetate fraction of Ribes fasciculatum (ERF) in mice. Test results of tail-immersion test and hot plate test revealed that the ERF had strong anti-nociceptive activities on thermal nociception in a dose dependent manner, indicating ERF's anti-nociception on the central pain. Moreover, the acetic acid-induced chemical nociception was also significantly reduced by ERF treatment. This result shows that ERF may also work on the peripheral pain. We further performed formalin test to confirm ERF's anti-nociceptive properties and found that pain responses were significantly decreased by ERF treatment. Interestingly, in the combination test with naloxone, the analgesic activity of ERF was not changed, indicating that the opioid receptor was not involved in the ERF-mediated anti-nociception. These results indicate that ERF might be possibly used as a painkiller for the treatment of nociceptive pains.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.250-255
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• 2008

This study utilized a high speed lap-shear test to evaluate the mechanical behavior of Sn-37Pb/Cu and Sn-37Pb/Electroless Nickel immersion Gold under bump metallization solder joints under high speed loading and hence the drop reliability. The samples were aged for 120 h at different temperatures ($120^{\circ}C,\;150^{\circ}C,\;170^{\circ}C$) and afterward tested at different displacement rates (0.01 mm/s to 500 mm/s) to examine the effects of aging on the drop life reliability. The combination of the stress-strain graphs captured from the shear tests and identifying a fracture mode dominant in the samples for different strain rates leads us to conclude that the drop reliability of solder joints degrades as the aging temperature increases, possibly due to the role of the IMC layer. This study successfully demonstrates that the analysis based on a high speed lap-shear test could be critically used to evaluate the drop reliability of solder joints.

• Journal of Korea Foundry Society
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• v.36 no.2
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• pp.60-66
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• 2016

In this study, comparison of corrosion properties of the Mg-1.5Ge-1Zn (GZ21) alloy and Mg-9Al-1Zn (AZ91) alloy were investigated. The studied alloys were fabricated by permanent mold casting method. And the potentiodynamic test, hydrogen evolution test, immersion test and A.C Impedance test were carried out in a 3.5% NaCl solution with pH7.2 at room temperature to measure the corrosion properties. The microstructure of GZ21 alloy was composed of ${\alpha}-Mg$ and $Mg_2Ge$ phases and AZ91 alloy was composed of ${\alpha}-Mg$ and $Mg_{17}Al_{12}$ phases. From the test results, the corrosion property was improved by adding Ge. It seemed that the corrosion mechanism was changed from galvanic corrosion (AZ91) to filiform corrosion (GZ21).

• Journal of Industrial Technology
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• v.22 no.A
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• pp.161-168
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• 2002

Latex modified concrete is governed by both cement hydration and polymer film formation processes in its binder phase. Such the reactions are expected to improve the polymer-cement co-matrixes themselves and the bond between the cement hydrates and aggregates, and to improve the properties of hardened latex-modified concrete. The purpose of this study was to study the strength and chemical resistance of Rapid-setting latex modified concrete(RSLMC) with the main experimental variables such as latex content(0, 5, 10, 15, 20%) and water-cement ratio(36, 38, 40%) at latex content 15%. Water absorption test was earned out to estimate water permeability resistance. Chemical resistance test was carried out to measure the weight change and to observe the appearance of RSLMC immersion in hydrochloric acid, sulfuric acid, and calcium choloride.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.5
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• pp.17-23
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• 2011

Steel clapping plate is used to connecting rubber body in rubber dam. However, once the steel clapping plate corrodes, it may cause faults, such as the same problems experienced by typical reinforcing steel. This study evaluated the applicability of glass fiber reinforced polymer composite(GFRP) clapping plate as a substitute for steel clapping plate. Absorption and load test were conducted to evaluate the decrease in durability of GFRP clapping plate exposed to deterioration environments. In the durability test results, the absorption rate of GFRP clapping plate was appeared as 0.6~1.0% in 50 day of immersion time. Also, the fracture load decreased with accelerated degradation environment exposure. Moreover, the absorption rate in GFRP clapping plate increased as degradation progressed, reducing the fracture load.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.519-522
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• 2005

As this study is to test effects of chemical attack on deterioration of cement mortars using in crushed sand. Besides tests have been carried out with cement mortars by river sand and crushed sand by fine sand, cement mortars mix various proportions of slica fume and fly ash(up to $15\%$ and $50\%$ by weight for cement) were prepared and immersed in pure water, sodium sulfate solution, magnesium sulfate solution, seawater for 28days. Test on the change in the weight and compressive strength of cement mortars according to the duration of immersion time and the content of slica fume and fly ash was performed.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.118-123
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• 2007

본 논문에서는 증강현실 기반 제품 디자인 시, 논문 [1]에서 제안된 몰입감 향상 기법들에 대한 사용성 평가를 통해, 사용자에게 다차원 피드백(multimodal feedback)을 제공하는 것이 몰입감 향상에 어떠한 영향을 미치는가에 대해 알아본다. 우선 기존의 데스크톱 기반의 디자인 환경과 다차원 피드백을 가능하게 하는 증강현실 기반 디자인 환경과의 비교 후, 시각 피드백에 대한 사용성 평가로써 증강된 가상객체에 의해 가려진 손을 다시 보이게 함으로 얻게 되는 실재감 향상 정도와 사용자의 입력에 따른 컨텐츠의 시각적 맵핑의 적절성을 평가한다. 또한 청각 피드백에 대한 평가 기준으로써 시나리오 상의 상황에 따른 배경음/효과음 맵핑의 몰입감과 적절성을 평가한다. 마지막으로 촉각 피드백에 대한 평가로써, 물리적인 감각형 객체에 가상객체를 정합함으로써 얻게 되는 촉감과 시나리오 상의 이벤트에 따라 제시되는 진동-촉각 피드백에 의한 몰입감 향상 정도를 평가한다. 제시된 사용성 평가의 결과는 기존의 증강현실 기반 디자인 시스템의 몰입감을 향상 시키기 위한 구현에 있어, 고려될 수 있는 사항으로써 의미가 있다.