• Journal of Sensor Science and Technology
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• v.24 no.1
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• pp.41-46
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• 2015

In this work, pure hierarchical ZnO structure was prepared using a simple hydrothermal method, and Ag nanoparticles doped hierarchical ZnO structure was synthesized uniformly through photochemical route. The reduced graphene oxide (rGO) has been synthesized by typical Hummer's method and reduced by hydrazine. Prepared Ag/ZnO nanostructures are uniformly dispersed on the surface of rGO sheets using ultrasonication process. The synthesized samples were characterized by SEM, TEM, EDS, XRD and PL spectra. The average size of prepared ZnO microspheres was around $2{\sim}3{\mu}m$ and showed highly uniform. The average size of doped-Ag nanoparticles was 50 nm and decorated into ZnO/rGO network. The $C_2H_2$ gas sensing properties of as-prepared products were investigated using resistivity-type gas sensor. Ag/ZnO-rGO based sensors exhibited good performances for $C_2H_2$ gas in comparison with the Ag/ZnO. The $C_2H_2$ sensor based on Ag/ZnO-rGO had linear response property from 3~1000 ppm of $C_2H_2$ concentration at working temperature of $200^{\circ}C$. The response values with 100 ppm $C_2H_2$ at $200^{\circ}C$ were 22% and 78% for Ag/ZnO and Ag/ZnO-rGO, respectively. In additions, the sensor still shows high sensitivity and quick response/recovery to $C_2H_2$ under high relative humidity conditions. Moreover, the device shows excellent selectivity towards to $C_2H_2$ gas at optimal working temperature of $200^{\circ}C$.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.3
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• pp.343-350
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• 2022

In recent years, nanomaterials, such as nano-silica, carbon nanotubes, and graphene oxide (GO), have been suggested to improve the properties of the interfacial transition zone (ITZ) between aggregates and cement pastes, which has most adversely affected the strength of quasi-brittle concrete. Among the nanomaterials, GO with superior dispersibility has been reported to be effective in improving the properties of ITZ of normal-strength concrete by forming interfacial chemical bonds with Ca²⁺ ions abundant in ITZ. In this study, the effect of GO on the properties of ITZ in the high-strength mortar was elucidated by calculating the change in hydration heat release, ITZ thickness, and the porosity around ISO sand, which was obtained with isothermal calorimetry tests and scanning electron microscope image analysis, respectively.

• Journal of the Korean Society of Costume
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• v.15
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• pp.47-54
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• 1990

Kyu-Soo Park wrote the book "Gur Ga Jap Bok Ko" (Proposition for Household Casuals) around A.D. 1865. He was a widely-learned man and a proponent of Korean self-consciou-seness like his fellow Pragmafist against then prevailing Chinese influence, which had already penetrated deeply into ordinary life style. According to this fact we can see not only the general dress-cystoms but the new customs of some high-birth People with evident self-consciouseness like him at that time. For example, they wore "Sim Eui" and "Bok Gun" as the dress of their ordinary life in spite of the general dress custom wearing the "Do Po" (Traditional Korean full-dress attire) and "Gat" (Traditional cylindrical Korean hat) as an ordinary or a ceremonial dress irrespective of rank at that time. Women wore an overcoat with "Chima" and "Jur. Go Ri" instead of the shortened "Jur, Go Ri" and buttock exagerating "Chima" largely popular at that time too. And also wore "So Eui" instead of "won Sam" or "Dang Eui" prevailing for the psychological resemblance of higher ranking group. Male yougnsters wore "Sa Gyu Sam" as an ordinary life dress and Girls wore "Chima and Jur Go Ri".

• Journal of The Korean Astronomical Society
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• v.37 no.4
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• pp.289-294
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• 2004

The main sources of interstellar dust are believed to be dust envelopes around AGB stars. The outflowing envelopes around the long period pulsating variables are very suitable place for massive dust formation. Oxygen-rich silicate dust grains or carbon-rich dust grains form in the envelopes around AGB stars depending on the chemical composition of the stellar surface. The dust grains expelled from AGB stars get mixed up and go through some physical and chemical changes in interstellar medium. There are similarities and differences between interstellar dust and dust grains in AGB stars. The mass cycle in the Galaxy may be best manifested by the fact that the dust grains at various regions have many similarities and understandable differences.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.2
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• pp.132-143
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• 1992

This paper presents a method in order to calculate the vortex distribution, the streak-line and the time-line around the flat and the cambered otter board in two dimensional flow using the discrete vortex method, and to calculate C sub(L) and C sub(D) of the otter boards varied with the passage of time by the numerical simulation using the Blasu's formula. The results obtained are summarized as follows: 1. Flow pattern around the otter boards calculated by the discrete vortex method was resembled closely that of the visualized photograph. 2. C sub(L) and C sub(D) calculated by the numerical simulation was very similar to the model test. 3. The circulation direction around the otter boards and the action direction of the shearing force can be recognized from the time-line around the otter boards. 4. Flow speed in the back side of the otter boards was faster than that in the front side, and the difference of the flow speed in both side of the cambered otter boards was about 1.3 times greater than that of the flat otter boards. 5. The clockwise vortex was generated in the trailing edge, and the counter-clockwise vortex was generated the leading edge of the otter boards. And they were shown the shape of Karman's vortex varied with the passage of time.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.1
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• pp.30-35
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• 2000

The experimental study on the lift-off height of diffusion flames was conducted to investigate the damage of swirl-coaxial injector used in $GO_2$/kerosene rocket engine during initial stage of ignition. To investigate the causes of damage and to prevent further damage of the injector, experimental injector was designed and hot fire tests were performed with varying propellant momentum ratio($\frac{Momentum of {GO_2}}{Momentum of Kerosene}$) from 1 to 12. In experimental coaxial injector, kerosene is sprayed from the central nozzle with swirl and $GO_2$ sprayed around the kerosene nozzle in the direction parallel to the axis of combustion chamber. Chamber pressure are close to the atmospheric condition. Lift-off height was measured by still images from camcoder and average values were used as data.

• Journal of the Korean Society of Costume
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• v.33
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• pp.73-88
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• 1997

In old Korea from the 4th century of 6th cen-tury the lapels of You and upper garment folded slightly. It had tight sleeves and its length was not long reaching to the hips. but from the 7th century the sleeve of You became wider and its length became longer, Chinese You folded very deeply across the breast and its sleeve was tight. The length of Chinese You was short too strectching out to the hips. From the 5th century the sleeve of the Chinese You became wider Chinese trousers with wide crotch appeared in the 4th century during the time when Ezst Jin Dyn-asty ruled China. The upper garments with the wide sleeve was common by the 7th century in China. What is specially noteworthy is that Short-dalnyung appeared in the 5th ∼6th century. In old Korea strings were used to tie the bottoms of the trousers. Trousers with tight crotch did not need the strins. korean trousers with wide lines were narrower than the Chinese trousers at the bottom and it was not necessary to use the strings for people to put them on In China there were both of wide trousers and tight trousers. People tied trousers around the kness with the strings in the formal places but they did not tied the trousers with the strings when they wore the ordinary clothes. Chinese trousers were very wide just like a skirt and they were much wider than wide Korean trousers.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.06a
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• pp.253-254
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• 2014

In offshore, various external forces such as wind force, wave force and impulsive breaking wave force act on offshore structures. Many researches about this forces are published. Kim and Cao(2008) published researche on wave force of vertical cylinder. Kim and Go(2013) performed research on the subgrade reaction by external forces. Among this forces, impulsive breaking force is more massive than other forces, especially. Therefore, the studies about impulsive breaking wave forces have been carried out. Chun and Shim(1999) analyzed dynamic behavior of cylindrical pile subjected to impulsive breaking wave force. In this study, when the impulsive breaking wave force acts on the offshore wind turbine, the subgrade reaction acting on the mono-pile of the offshore wind turbine is calculated by p-y curve. The calculation is carried out to the multi-layered.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.579-584
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• 2003

In this study, anisotopic yield function is proposed for the numerical analysis of reinforced tunnel ground with grouting. For this, material properties of the reinforced ground both by equilibrium as well as kinematic condition along the interface and by the mean field theory of Eshelby (1957) and Zhao (1990) are compared with each other and, as a result, the advantage/disadvantage of the proposed models are summarized. Finally, reinforced ground around tunnel with grouting is analyzed numerically. A new anisotropic yield function model is shown to be more reliable than the previous one and the predicted result is agreeable with the experimental data available.

• Journal of the Korean Society of Costume
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• v.50 no.8
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• pp.113-128
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• 2000

This essay examines the costumes for gods and priests in ancient Mesopotamia as they are depicted in various documents and artifacts of the period, and it is part of an ongoing project that studies the process in which the religious costumes, the means of religious communication, of ancient Mesopotamia had evolved. The study shows that the religious costunmes in ancient Mesopotamia have following characteristics. 1. The costumes for gods are the same as those for men, including warp-around skirts, tierd skirts, shawls, and tunics. However, there are some differences : costumes for gods include such distinguishing features as aprons and long tassels. 2. Both wear stylized headpieces that indicate their divinity and have long hair and long beard. 3. As for shoes, the Sumerian and Babilonian gods go barefoot, but the militant Assyrian gods wear sandals. 4. Sumerian and Babilonian figures do not have much, but the Assyrian gods wear various ornaments including earrings and bracelets that emphasize their muscular physique. 5. Priests wear weird skirts or wrap-around skirts but no top. They have shaved hair to indicate their role as purifiers, but some of them have long beards.