• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.6
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• pp.699-705
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• 1985

Heat transfer characteristics in terms of the tube wall-temperature and the enthalpy have been investigated utilizing ribbed (rifled) tubes in order to enhance heat transfer performance. Considerations were given for the cases of smooth tubes in order to compare with the case of ribbed tubes. The tilt angle of the experimental tubes are from 0.deg. to 90.deg. , in order to simulate the boiler water tubes having 15.deg.-90.deg. inclined angle in boiler nose and studded tubes (burner zones), Natural convection and forced convection (Re=1810) conditions were considered in the experiments. The experimental results for the effect for the tube inclination through a natural convection and forced convection are presented and it is shown that ribbed tubes permit an appreciable increase in heat transfer coefficients and consequently it means substantial reductions in boiler water wall tubes and heat exchanger surface areas.

• Journal of the Korean Society of Costume
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• v.23
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• pp.151-168
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• 1994

The purpose of this study is to examine all kinds of Kwanmo of Kokuryo. The results are as follows . There are nine kinds of Kwanmo in Kokuryo : Kun(건), Chaik ( 책), Jeolpoong(절풍), Sogol (소골), Jowookwan (조익관), Rakwan (라관), Kagkwan(각관), Rip(립) and Jumdongkwan (금동관), Kun(건) is a piece of cloth which covers hair. There are two types of kun(건) : Hari band type and entire head cover type. Chaik(책) was originated in China , but people of Kokuryo didn't wore chinese Chaik (책) as it was. They created unique shape of their own. Jeolpoong (절풍) is the cone-shaped knwanmo which is chiefly made of leather. In the early period it was worn by the nobility , but gradually trickcled down common people's Kwanmo. Sogol(소골) is the cone -shaped Kwanmo which is made of silk and decorated with gold and silver. Only the nobility wore it, Jowookwan(조익관) is the knwanmo decorated with natural bird feather or metallic feather. Mainly it was worn by the nobility in hunting , Besides, worriors, diplomats, dancers and musicians wore it. Rakwan (나관) was worn by the highest class. There were three kinds of Rakwan (나관) : Baekrakwan(백나관). Cheongrakwan (청나관) and Birakwan (비나관). The king of Kokuryo wore BAekrakwan (백나관). It was simlar ini shape to chines Mookwan (무관). Kagkwan (각관) was the kwanmo unique to Kokuryo. It was used by the nobility . Rip (립)was originated on purpose to protect people form the sunshine or rain. There were two kinds of Rip(립) ; Bangrip (방립) and Pyungyangja(평량자). The former was used by the nobility, the lattr was used by common people in hunting . The Kwanmo which was decorated with gold and silver developed into Kumdongkwan(금동관). The Kwanmo which is similar to Kumkwan (금관) of Baekje and Shilla has been shown in Kaimachong (가마총) 무 dJumdongkwan(금동관) was excavated in the ancient tombs of Kokuryo.