• Journal of the Korean Society for Heat Treatment
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• v.31 no.3
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• pp.104-110
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• 2018

The effects of heat treatment time and cooling method on microstructure and mechanical property of Cu-22wt%Sn alloy were discussed. ${\alpha}+{\delta}$ mixed phase structure was obtained in air-cooled specimens after heat treatment at 775, 750, and $700^{\circ}C$ for 1 hour. On the other hand, in water-cooled specimens, ${\alpha}+{\beta}^{\prime}$ martensite mixed phase was obtained. In the case of water-cooled specimens, the hardness value decreased with decreasing heat treatment temperature because the volume fraction of ${\alpha}$ phase with low hardness value increased as the heat treatment temperature decreased. In water-cooled specimen after heat treatment at $600^{\circ}C$, ${\gamma}^{\prime}$ martensite was formed instead of ${\beta}^{\prime}$ martensite. The hardness value of ${\gamma}^{\prime}$ martensite was lower than those of ${\beta}^{\prime}$ and ${\delta}$ phases.

• Transactions of the Korean Society of Mechanical Engineers
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• v.6 no.4
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• pp.353-360
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• 1982

The determination of the natural frequencies and mode shapes for thin conical shell is an important step not only in the investigation of the dynamic response of the composite structures such as missile cone, mose firings, but also in the analysis of the acoustic behavior of bells. A Rayleigh-Ritz procedure was used to determine the natural frequencies for a certain class of mode shapes of a thin conical shell built in on the edge with the smaller radius and free on the other edge. Both bending and extensional energy are included in the analysis. This paper described the experiments on the two natural frequencies which are present in association with two preferential modal directions, as a result of imperfection of the thin conical shell. Experimental work was conducted on two different bronze conical shells. One of these was specially designed to the effects of the adding distributed mass to the end of the conical shell. The other shells were identical in all dimensions except that of the thickness to the end of the conical shell. In this paper, the effect of a adding mass to a conical shell was investigated. Experimental result was that the magnitude of the natural frequency rate and the increase of depth of beat frequency depend upon the location of adding lumped mass on the surface of the conical shell.

• Journal of Fashion Business
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• v.20 no.3
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• pp.68-88
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• 2016

The purpose of this research is to investigate the characteristics of Chinese minority women's waistbands, in view of their lifestyle, costume, and symbolism. The research method combined literature research and case study. In the case study, this research targeted the secondary data of a total of 215 pieces from books, articles and the internet. A total of 5 pieces per each representative women's waistband of 43 minorities, excluding those who did not wear a waistband, we collected. We then quantitatively analyzed the form and decoration of the waistbands. As a result of considering the form, the waistbands of Chinese minorities per region were closely related to the costumes, mainly showing high similarity in respect to color and decoration. Moreover, the decorations of the waistbands were most often made from their own area's special products, such as silver, bronze, cotton, and linen, amongst other. The form and decoration of the Chinese minority women's waistbands were all connected with functionality, aesthetic impression, and symbolism, which can be said to be an important part of understanding Chinese minority costume culture. This research contributes to the development and preservation of Chinese minorities' costume culture by considering and analyzing unique costume factors besides giving excellent fashion design ideas for contemporary fashion.

• Journal of Energy Engineering
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• v.12 no.1
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• pp.17-22
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• 2003

The present study was conducted to obtain the fundamental knowledge on the manufacturing and operating characteristics of a small scale CPL (Capillary Pumped Loop) heat pipe. CPL heat pipes are able to transfer heat effectively at any orientation in a gravitational field over long distances. An experimental model with an evaporator of a circular plate shape was designed and manufactured and its operating performances were tested. A Bronze powder sintered metal plate of 3 mm thick and $\Psi$ 50 mm was used as wick and ethanol was used as working fluid. An experimental apparatus was set up to ascertain the operating conditions oi CPL at different heat load and an surrounding temperature at the condenser was maintained about 13$^{\circ}C$.

• Special Issue of the Society of Naval Architects of Korea
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• 2009.09a
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• pp.1-5
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• 2009

Recent growth in global economic situation has led dramatic increase in new buildings of large containerships. These increased new building orders have brought keen concerns of developing and improving the quality of design and increasing the productivity of the vessel in order to satisfy the ship Owner's various requirements. For the increment of productivity and quality of containership, the plastic type bearing pad of cargo hatch cover has been investigated intensively for years with the supplier of cargo hatch cover. The result of investigation showed that there are numbers of advantages for the Owner and Builder over the existing bronze bearing pads which are better corrosion resistance long life time, low friction coefficient, easy maintenance, easy installation, better production lead time and low maintenance cost.

• Journal of Conservation Science
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• v.22
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• pp.5-14
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• 2008

The effect of air pollutants coming from internal museum materials such as wood-based products and cements on metal corrosion have been investigated. The Oddy test and the Chamber test was employed as a corrosion test. The metal pieces after the Oddy test had different corrosion types caused by the internal museum materials. The most effective wood based product was 18T HS(E0) and 9mm plywood(F0,E0). Iron(Fe) and copper(Cu) also bronze of the Chamber test had corrosion caused by Formic acid, Acetic acid, and Acetaldehyde. The packing materials in high humidity had caused more corrosion on the surface of the metal pieces than in low humidity.

• Journal of the Korean Society of Food Culture
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• v.12 no.1
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• pp.11-16
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• 1997

The Nara Dynasty of Japan lasted from 710 to 784 A.D, which corresponds to the period of the Unified Shilla Kingdom of Korea. The Nara Dynasty enacted the 'Daiho Law and Ordinance' by referring to those of Tang Dynasty of China. Under these legal systems, the Ministries were defined, and foods were used for paying taxes or as currency. The characteristics of the dietary culture in Nara Dynasty were as follows. 1) They obtained food from rice and other grain farming, hunting and fishery. Rice was their main staple and was also used for preparing porridge and brewing wine. 2) Under the influence of Buddhism, meat was prohibited, and milks or dairy products were supplemented for improving malnutritional status. 3) They also used seasonings, spices and sweeteners to enhance the taste and produced medicines by extracting plants, animals and minerals. 4) While chopsticks were made of bamboo, willow, silver, shell, tree or bronze, such utensils as pan earthenware steamer, or charcoal pots were used for preparing meals. 5) Highly qualified utensils, made of porcelains painted with lacguetr, metal, glass, horn and stone, were produced as handcraft art wad developed. 6) Chinese style cousines and cooking methods were popular and various types of preserving techniques like drying or salting were used. Processed cookies were also developed. 7) Although flour was used mainly among noble class people, ordinary people also used it. The royal families ate milk products a lot and even fried foods. 8) One can say that Buddism exerted an influence on Vegetarianism from this era.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.6
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• pp.714-720
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• 2003

Due to the electric power shortage in summer season and regulation of freon refrigerant, the application of gas absorption refrigeration and hot water systems are considerably increasing trend. But, this system consists of condenser, heat exchanger, supply pipe and radiator etc. which are easily corroded by acidity and dissolved oxygen and gases. In result, this system occurs scale attachment and corrosion damage like pitting and crevice corrosion. In this study, electrochemical polarization test of heat exchanger tubing material (copper, aluminium brass, 30% cupronickel(30% Cu-Ni)) was carried out in 60% lithium bromide solution at $95^{\circ}C$. As a result of polarization test, corrosion behavior by impressed potential and local corrosion. such as galvanic corrosion, pitting corrosion behavior, of tubing materials was investigated. The main results obtained are as follows: (1) The effect of pitting and crevice corrosion control of 30% cupronickel in 60% LiBr solution at $95^{\circ}C$ is very excellent. (2) Dissimilar metal corrosion of 30% cupronickel coupling to aluminium bronze is the most sensitive. (3) Current density behavior of tube materials by impressed potential is high in order of copper > aluminium brass > 30% cupronickel.

• The Korean Journal of Quaternary Research
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• v.19 no.2
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• pp.13-17
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• 2005

The Khogno Khan mountain special protected area belongs to Khogno Khan subdistrict of Gurvanbulag district of Bulgan Province and is 46.9 sq.km. with its main feature being mountain forest zone. In this paper we present some results of research of the Anthropological and archaeological team of Mongolian Korean Joint research expeditions carryied out in Khogno Khan mountain special protected area from 27 July to 1 August, 2000. During archaeological reconnaissance we discovered around 27 localities of archaeological monuments belonging to different historical periods (from the Neolithic up to the Mongolian period, $13^{th}-17^{th}$ Century) in the territory of the Khogno Khan special protected area. Based on the results, we especially want to point out 1). The archaeological and historic monuments (from the Neolithic up to modern era) found in the Khogno Khan mountain and its surrounding area show that since the Neolithic period (around 8000 years ago) this area was occupied by the ancestors of Mongolians and it was used during subsequent historic periods on the one hand. 2). On the other hand the Khogno Khan mountain region was one area where there occurred intensive admixture between populations of Kurgan culture, Deerstone culture from the West Mongolia and the population of slab graves culture from Central and East Mongolia during Bronze and Early Iron Age. 3). Today the mountain is one of the area with a unique assemblage of archaeological monuments from different historic periods, what naturally seems like an open-air natural museum of Mongolian Prehistory.

• Journal of Conservation Science
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• v.16 s.16
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• pp.15-20
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• 2004

Two pieces of choson-Tongue(朝鮮通寶) minted at 1423 A.D. were analyzed by atomic absorption spectroscopy and neutron activation analysis. The measurement of lead isotope ratios was also carried out in order to predict the provenance of raw materials used for minting. The Chosen-Tongue was minted as bronze having the chemical compositions of $Cu\;90\%,\;Pb\;3\~4\%,\;Sn\;2\~3\%$, which were different from the typical composition of Chinese and Japanese coins. The results of lead isotope ratios showed that the provenance of raw materials used for minting had a possibility to be originated from South China. And application of statistical linear discriminant analysis (SLDA) to the provenance of lead used for minting of Chosen-Tongue was confirmed.