• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.5
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• pp.569-580
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• 1998

In this study, condensation heat transfer coefficients(HTCs) of a plain tube, low fin tube, and Turbo-C enhanced tube for CFC-11, HCFC-123, CFC-12, HFC-l34a are measured and compared against each other. All data are taken at the vapor temperature of 39$^{\circ}C$ with a wall subcooling temperature 3~8$^{\circ}C$. Test results show that HTCs of a low vapor pressure refrigerant, HFC-123, for a plain, low fin, and Turbo-C tubes are 10.5~20.5%, 8.2~12.2%, 16.5~19.2% lower than those of CFC-11, respectively. On the other hand, HTCs of a medium vapor refrigerant, HFC-l34a, for a plain, low fin, and Turbo-C tubes are 20.6~31.8%, 0.0~8.0%, 13.2~20.9% higher than those of CFC-12, respectively. For all refrigerants tested, HTCs of Turbo-C tube are the highest among the three tubes showing almost 8 times increase in HTCs as compared to those of a plain tube. Nusselt's prediction equation for a plain tube yielded 12% deviation for all plain tube data while Realty and Katz's prediction equation for a low fin tube yielded 20% deviation for all low tube data.

• Journal of the Korean Home Economics Association
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• v.26 no.4
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• pp.1-13
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• 1988

The purpose of this study is to investigate water and after vapor transport characteristics of underwear fabrics. Experimental materials were cotton woven fabric and cotton knitted fabric, nylon tricot (untreated and hydrophilic finished) and cotton/polyester/cotton triple layer. Cotton knitted fabric have three types of knit structure (interlock, rib, plain stitch) and knit with either 38's or 60's combed yarn. And cotton woven fabric have plain weave with 60's combed yarn. As experimental methods, vapor cup test, dynamic method, vertical wicking test and transplanar uptake test were used. The results are as follows. 1) In cotton specimens, the order of water vapor transpiration (wvt) was plain > rib > interlock in the same yarn diameter. The knit fabric of thinner yarn showed the better wvt among the same knit structure. 2) In cotton specimens, the order of water absorbency was interlock > rib > plain in the same yarn diameter. the knit fabric of thicker yarn showed the better absorbency among the same knit structure. 3) When knit fabric (60's plain) is compared with woven fabric 960's plain), knit fabric showed faster rate of wvt, more amount of uptake and slower rate of water uptake than woven fabric did. 4) When compared untreated nylon with hydrophilic finished nylon, hydrophilic finished nylon showed much more water absorbency than untreated nylon did, but showed same rate of wvt. 5) The water transport characteristics of triple layer underwear fabric showed that the thinner and the lighter one, the better wvt and absorbency did.

• Journal of the Korea Institute of Building Construction
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• v.22 no.5
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• pp.431-439
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• 2022

In this study, Neutralized red mud(LRM+S) at a pH of 6-8 was prepared by adding sulfuric acid to liquefied red mud(LRM) at a pH of 10~12. After adding LRM and LRM+S to the cement paste, the hydration heat, compressive strength, and hydration products were examined. The observed accumulated hydration heat revealed that the calorific value of the cement paste with LRM was low and its and peak was delayed when compared with that of plain cement paste(referred to as Plain), whereas the calorific value of the cement paste with LRM+S was similar to that of Plain. At the age of 28 days, the compressive strength of the cement paste with 20% LRM was 55% of the strength of Plain. Using X-ray diffraction, it was determined that the cement paste with 20% LRM exhibited a Ca(OH)₂ peak after 3 days, whereas the cement paste with 20% LRM+S and Plain exhibited a Ca(OH)₂ peak after an hour. Thus, the strength degradation of cementitious materials was improved by adding neutralized red mud prepared by adjusting the pH of highly alkaline LRM with sulfuric acid.

• Journal of Korean Medical classics
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• v.26 no.4
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• pp.203-221
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• 2013

Objectives : The Major Essentials of Huangdi's Internal Classics Plain Questions (黃帝內經素問大要, MEHP) is one of the late-Chosun's literate physician Lee Gyoojoon (李圭晙, 1885-1923)'s main work, which is known to have logically proofread the Huangdi's Internal Classics Plain Questions (黃帝內經素問, HP). This study aims to examine two elements of the text: (1) the types of MEHP currently in circulation; (2) the types of publications of HP to be the MEHP's original script. Methods : In this study, basically bibliographical analyses of the form and contents was utilized about the types of MEHP and HP. However, to compare the sentences and phrases between prints, I've used 20 examples that Qian Chaochen (钱超尘) had proposed in his preceding studies. Also, regarding Lee Wonse (李元世)'s proofreading on the MEHP in 1999, I've used interviews of his students. Results : First, I've discovered that there are three versions MEHP in circulation: the woodblock printed version; Lee Wonse's handwritten version; Lee Wonse's proofreading version; and confirmed that Lee's proofreading version should be regarded as good version of MEHP. Also, I've discovered the possibility of other types of printed versions of the MEHP in existence, which is considered Lee's handwritten version's original draft. Second, I've confirmed that the original script of HP, which Lee Gyoojoon utilized for MEHP, is indeed not Gu Congde (顧從德) printed version HP, however, is the Chosun's bureau for military drill (訓練都監) printed version HP. Conclusion : Through this study, I've provided strong evidence that Lee Gyoojoon's MEHP is a unique and original research completed within the traditional realm of Korean medicine, which possesses the universality of Eastern Asian medicine represented by Huangdi's Internal Classics (黃帝內經).

• Journal of the Korean Society of Costume
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• v.58 no.1
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• pp.9-16
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• 2008

Six of the Imdang tombs containing remains with imprints of ancient fabrics and textiles were investigated. Within the tombs, a total of 120 pieces of imprinted fabrics and textiles were investigated, all of which belongs to $5{\sim}6C$ Shilla period. All of the hemp textiles examined exhibited similar characteristics found in ancient hemp textiles: they were woven by plain weave technique with s-twist threads. The examined silk could be categorized into plain woven silk, cho, and double woven brocade, all of them made with non-twisted threads and degummed silk. The density of the plain woven silk ranged from 39 threads to 144 threads. Cho was also found, which showed similar characteristics to those of Gaya and Bakjae tombs. One piece of 2/1 twill weave on plain ground and 12 pieces of double woven brocade were found and their average density was $97.4{\times}33.4/cm$ with denser warp than weft. The various thickness of the threads were observed in the examined plain braid. The silk with twining technique showed thicker warp than weft. This is similar to the techniques of fabrics found in the King Muryeoung's Tomb of the Bakjae period. Fabrics with the purple-like color were observed in the some of the double woven brocades and also on the plain woven silk imprinted on the remains. The purple-like color was revealed to be purple with a tint of violet. The two tombs from which the imprinted fabrics with purple-like color were found belonged to top-class social level of the Shilla period, which informs that the purple color was used exclusively for the people of higher social status. The floss silk was found between the double woven brocade and plain woven silk of the belt, which is an important evidence that the floss silk was used for stuffing in the early 6th century.

• Journal of the Korean Society of Costume
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• v.33
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• pp.41-54
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• 1997

The objectives of this study were to find out the relationships between clothing style pre-ferences and self-image and to examine the differences in clothing style preferences ac-cording to marital status educational level and social stratification of women. The drawings of clothing style were designed referring to the catalogues for spring/summer of 1996 and printed by computer 6 styles of suit corresponding to clothing image were selected. Style A is a brown suit decorated with scarf style B a grey suit with stripes C a yellow suit with printed pattern D a grey and beige suit E a chanel suit decorated with corsage and F a blue suit with pleated skirt. The self-image was separated to the actual self-image and the ideal self-image. Samples were 226 women(ages 18 to 37) in Seoul Korea. The results of the study were the followings. 1. Clothing images of 6 styles were estimated; Style A was plain conservative formal and gentle image ; B masculine solid actual dark and plain image; C feminine romantic bright and splendid image; D actual ordinary un-fashionable and plain image; E feminine ten-der romantic and non-active image ; F indi-vidual fshionable open casual sprightly and active image. 2. There were significant relationships be-tween clothing style preferences and realistic self-image. The women who considered them-selves as masculine preferred style B mascu-line and plain image. The women feminine and conservative preferred style E feminine and tender image. The women not to follow the fshion preferred style D ordinary and plain image. The women informal and open pre-ferred the style F casual and active image. 3. There were significant relationships be-tween clothing style preferences and ideal self-image. The women who wanted to be-tween clothing style preferences and ideal self-image. The women who wanted to be con-sidered themselves as feminine and conserva-tive preferred style E feminine and tender im-age. The women who wanted gentle and con-servative preferred style D ordinary and plain image. The women who wanted sprightly pre-ferred the style F casual and active image. 4. There were significant differences in clothing style preferences according to marital status educational level and social stratifi-cation. The women with more eduacation pre-ferred the splendid and the plain image at the same time. The upper class preferred feminine image and lower class casual and active image.

• Journal of Korea Water Resources Association
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• v.31 no.5
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• pp.515-528
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• 1998

A quasi-two-dimensional model for simulating the flood plain flow is developed. The model consists, in general, of a multiply-connected network which combines the main channel and two-dimensional flood plain cells. The main channel flow is described by the Saint Venant equations for one-dimensional unsteady flow, and the flood plain flow by the cell continuity and river-or weir-type stage-discharge relations between flood plain cells. The implicit algorithm for unsteady flow in looped channel network is extended to incorporate the flood plain flow. To verify the performance of the model, it is applied to three test problems, and sensitivities to various model parameters are analyzed. It turns out that the present model gives more accurate result than that by Cunge (1975) as the shape of cross section becomes more complex and irregular. Not only the inundation of water from the main channel but the return flow from the flood plain is successfully simulated.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.8
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• pp.656-663
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• 2002

Flow condensation heat transfer coefficients (HTCs) of R22, R134a, R407C, and R410A were measured on horizontal plain and microfin tubes. The experimental apparatus was composed of three main parts; a refrigerant loop, a water loop and a water/glycol loop. The test section in the refrigerant loop was made of both a plain and a microfin copper tube of 9.52 mm outside diameter and 1.0 m length. The refrigerant was cooled by passing cold water through an annulus surrounding the test section. Tests were performed at a fixed refrigerant saturation temperature of $40^{\circ}C$ with mass fluxes of 100, 200, and 300 kg/$m^2s$. Test results showed that at similar mass flux the flow condensation HTCs of R134a were similar to those of R22 for both plain and microfin tubes. On the other hand, HTCs of R407C were lower than those of R22 by 11~l5% and 23~53% for plain and microfin tubes respectively. And HTCs of R410A were similar to those of R22 for a plain tube but lower than those of R22 by 10~21% for a microfin tube. In general, HTCs of a microfin tube were 2.0~3.0 times higher than those of a plain tube.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.6
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• pp.1727-1733
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• 2015

In the present study, the heat transfer performance of dimpled double-pipe heat exchangers for fuel cells that are utilized as cooling systems of fuel cells was studied. In addition, to comparatively analyze the heat transfer performance of dimpled double-pipe heat exchanger for fuel cells, plain double-pipe heat exchangers were also studied. Experimental results were derived on changes in the Reynolds numbers of the cooling water flowing in dimpled and plain double-pipe heat exchangers and changes in the heat flux of the air. Thereafter, to verify the reliability of the experimental results, the theoretical overall heat transfer coefficients and the experimental overall heat transfer coefficients were comparatively analyzed and the following results were derived. The heat transfer rate lost by the hot air and that of the heat transfer rate obtained by the cooling water were well balanced. The experiments of plain double-pipe heat exchangers and dimpled double-pipe heat exchangers were conducted under normal conditions and the theoretical overall heat transfer coefficient and the experimental overall heat transfer coefficient coincided well with each other. In both plain double-pipe heat exchangers and dimpled double-pipe heat exchangers, heat transfer rates increased as the cooling water flow velocity increased. Under the same experimental conditions, the heat transfer performance of dimpled double-pipe heat exchangers was shown to be higher by 1.2 times than that of plain double-pipe heat exchangers.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.10
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• pp.1343-1350
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• 2000

The evolutionary structure of tip vortices has been investigated with a two-dimensional LDV system for a plain and a slotted blade, respectively. To analyze the effect of slots which bypasses a part of main stream into the tip face, velocity profiles, vortex sizes, their displacements and turbulence intensities during one revolution of the rotor were measured by the phase averaging process. For the comparison of circumferential velocity components of the plain blade and the slotted blade, the peak values of the slotted blade were lower than those of the plain blade, and axial velocity components of the slotted blade were considerably larger than those of the plain blade. The slotted rotor blade enlarged the core size and made the vortex delayed compared with those of the plain blade at the same wake ages. Turbulence profiles had peaks inside the core radii and decayed gradually in the radial direction of vortex coordinate. Also, using a quasi 3-D LDV measurement technique the budget of turbulence kinetic energy was analyzed in radial direction of the vortex core.