• Applied Chemistry for Engineering
• /
• v.9 no.2
• /
• pp.177-184
• /
• 1998

The contact angle on powder hydrophobic polymer PMMA(polymethylmethacrylate), PVC(poly vinyl chloride) and hydrophilic metal aluminium was measured by wicking method on the base of Washburn equation for water, glycerol, formamide, diiodomethane, 1,1,2,2-tetrabromoethane, 1-bromonaphthalene, acetone, chloroform, benzene, ethanol, methanol, and for anionic surfactant SDS(sodium dodecyl sulfate) and cationic surfactant CATB(cetyl trimethylamonium bromide) aqueous solution with concentrations. The values of ${\gamma}_c$ estimated by Zisman plot and adhesion tension plot for contact angle with organic liquids, SDS, and CTAB aqueous solutions were 43.5, 28.3, and $36.2mNm^{-1}$ for PMMA and 44.2, 25.0, and $34.8mNm^{-1}$ for PVC, respectively. From the results, it was considered that wettability and characteristics of solid surface were transformed by adding surfactant. The surface free energy, ${\gamma}_s$ and its components of PMMA, PVC, and aluminium were determined using harmonic equation.

• Journal of architectural history
• /
• v.17 no.4
• /
• pp.65-82
• /
• 2008

The wooden pagoda sites which have been confirmed in Baekjae's former territory so far have flattened surface of the earth or foundation pert made by digging up the earth. In particular, the latter is found more often in the pagoda sites of Baekjae, which is essential and absolutely necessary because of the characteristics of pagoda structure. The wooden pagoda sites with foundation part made by digging up the earth under the stylobate are found at Yongjeongli ruined temple site of Woongjin area, and at Neung-sa temple site, Wangheung-sa temple site, Geumgang-sa temple site, and Mireuk-sa temple site of Sabi period. They are also observed at Hwanglyong-sa nine-storied wooden pagoda of Shilla and at Biin five-storied stone pagoda of early Goryeo. They are important data improving that the construction technologies of Baekjae continued to be applied to build stone or wooden pagodas, transcending time and space. Recently, the site assumed as a wood pagoda site of Hanseong area was examined in Gyeongdang sect ion of Pungnap mud fortification. If this is proved to be a real wooden pagoda site, this digging-up construction technology of foundation part ann be concluded to be a traditional engineering technology of Baekjae which was frequently used from Hanseong period to Sabi period. On the other hand, this digging-up construction technology of foundation part has been found only at pagoda sites and main building sites of temple ruins, and it helps examine their symbolism.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.26 no.3
• /
• pp.448-457
• /
• 2002

Heat treatment such as quenching of a high-temperature cylinder is being used on steel to produce high strength levels. Especially, the mist cooling with the high and uniform surface heat flux rate s expected to contribute for better products. The experimental mist cooling curve is produced for better understanding, and two distinct heat transfer regions are recognized from the cooling curve produced. It is shown that the liquid film evaporation dominated region follows the film boiling-dominated region as decreasing the temperature of test cylinder by mist flow. Based on the intuitive view from some previous investigations, a simplified model with some assumptions is introduced to explain the mist cooling curve, and it is shown that the estimation agrees well with our experimental data. In the meanwhile, it is known that the wetting temperature, at which surface heat flux rate is a maximum, increases with mass flow rate ratio of water to air ($\varkappa$ < 10). However, based on our experimental data, it is explained that there exists a critical mass flow rate ratio, at which the wetting temperature is maximum, in the range of 3 < $\varkappa$ < 130. Also, it is described that despite of the same value of $\varkappa$, the wetting temperature may increase with mist velocity.

• Polymer(Korea)
• /
• v.24 no.6
• /
• pp.869-876
• /
• 2000

In order to improve the cell-compatability of poly(L-lactide-co-glycolide) (75 : 25 by mole ratio of lactide to glycolide, PLGA) surfaces, the physicochemical treatments have been demonstrated. Chemical treatments were 70% perchloric acid. 50% sulfuric acid and 0.5 N sodium hydroxide solution and physical methods were corona and plasma treatment. The water contact angle of surface treated PLGA decreased from 73$^{\circ}$ to 50~60$^{\circ}$, i.e., increased hydrophilicity, due to the introduction of oxygen-containing functional group onto PLGA backbone by the measurement of an electron spectroscopy for chemical analysis. It could be observed that the adhesion and growth of fibroblast cell on physicochemically treated PLGA surfaces, especially perchloric acid treated PLGA surface, were more active than on the controt. In conclusion, it seems that surface wettability as hydrophilicity of PLGA plays an important role in cell adhesion, spreading and growth.

• Korean Journal of Medicinal Crop Science
• /
• v.21 no.1
• /
• pp.39-44
• /
• 2013

This study was conducted to identify the effect of shading and pinching on growth and acanthoside-D content of Acanthopanax divaricatus var. albeofructus and A. koreanum Nakai. Different pinching heights showed no significant differences in terms of plant growth and acanthoside-D content but higher values showed that pinching A. divaricatus at 60 cm and A. koreanum at 30 cm favored good growth and higher fresh weight in the shoots. The content of acanthoside-D was not significantly affected by pinching heights. Also, no significant difference in acanthoside-D content was found between the lower and upper part of plant in the first year. However it was much higher in the lower part than the upper part in the second year, which indicated that the content of acanthoside-D was comparatively high in the lower part where lignification is much advanced. Shading showed benefits in terms of growth of A. divaricatus while only 50%-shading was favorable for A. koreanum to achieve superior growth. Overall, results indicated that shading had favorably affected the growth of the 2 Acanthopanax species while no-shading is better if we opt to achieve higher acathoside D content.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.32 no.3
• /
• pp.310-316
• /
• 1987

A field experiment was conducted to find out the effects of liming(soil pH) and sources of N on growing characters and yield of burley tobacco. Treatments consisted of liming(nonliming, liming to soil pH5.5 and 6.5) as the main plot and N sources(compound fertilizer of containing 3.9% NH$_4$-N and 6.1% NH$_2$-N, NaNO$_3$,(NH$_2$)$_2$CO and (NH$_4$)$_2$SO$_4$as the sub-plot. The growth of vegetative growing stage of limed plots were delayed(to compare the nonlimed plot) by influence of alkali. When the source on N was NaNO$_3$ the growth of vegetative growing stage was unfavorable and the yellowing of lower leaves of maturing stage was rapid. The yield and value of cured leaf was increased by increasing the rate of Ca(OH)$_2$, but there was no significant differences among the source of N. The yield response to liming was greater when the source of N was (NH$_4$)$_2$SO$_4$ than that of any other plots.

• Journal of Korean Medical classics
• /
• v.13 no.1
• /
• pp.1-16
• /
• 2000

대태극적내용화재인신내응장하처간작태극적문제진행료고찰(對太極的內容和在人身內應將何處看作太極的問題進行了考察), 득도료여하결론(得到了如下結論). 1. 태극최조재주역계사전중유공자장태극제시위팔괘생성적기본원리(太極最早在周易繫辭傳中由孔子將太極提示爲八卦生成的基本原理), 지후(之後), 량한도당대적저일기간내(兩漢到唐代的這一期間內), 인위태극시창조만물적원시적혼돈지기(認爲太極是創造萬物的原始的混沌之氣), 중앙원기(中央元氣), 몰유분화위음양적기적개념(沒有分化爲陰陽的氣的槪念), 당시피해석위우주간최초적혼연일체적원기적사상점료주류(當時被解釋爲宇宙間最初的渾然一體的元氣的思想占了主流). 2. 주돈신작태극도설(周敦?作太極圖說), 최초제시료무극적개념(最初提示了無極的槪念), 지후(之後), 이주자위대표(以朱子爲代表), 송대적성리학자장태극해석위만물중적궁극지리(宋代的性理學者將太極解釋爲萬物中的窮極之理), 최초장태극해석위리(最初將太極解釋爲理). 3 한동석계승료금일부적삼극설(韓東錫繼承了金一夫的三極說), 이삼극적변화원리설명료태극(以三極的變化原理說明了太極).. 손일규(孫一奎), 조헌가(趙獻可), 장개빈등주장명문설(張介賓等主張命門說), 견지명문위태극(堅持命門爲太極), 인위저명문위우태극적본체수기작용적신장지간(認爲這命門位于太極的本體水起作用的腎臟之間), 동통제수화(同統制水火), 추동인체생명력적원천(推動人體生命力的源泉), 인차여철학상소론급적태극적개념유류사지처(因此與哲學上所論及的太極的槪念有類似之處). 4. 황원어주장적중기위태극설(黃元御主張的中氣爲太極說) 인위태극내창조생명적근원지기(認爲太極乃創造生命的根源之氣), 창조지후야불단공급생명(創造之後也不斷供給生命) 력적중기구유태극적속성(力的中氣具有太極的屬性). 재저일점상가이해석위수토합덕지공적위치(在這一点上可以解釋爲水土合德之空的位置), 대차환유대진일보적고찰(對此還有待進一步的考察). 5. 소동진주장적비위태극설인위비위십토(邵同珍主張的脾胃太極說認爲脾爲十土), 위생명통일적기초(爲生命統一的基礎), 인차응파타인위시무극위타(因此應把?認爲是無極爲妥). 6. 소강절주장적심위태극설인위만물중매일물도시일개태극(邵康節主張的心爲太極說認爲萬物中每一物都是一?太極), 구유태극적속성(具有太極的屬性), 심재오행중속화(心在五行中屬火), 위발동광명지처(爲發動光明之處), 인차이삼극적원리래간(因此以三極的原理來看), 이오토장태극수진행분열(以五土將太極水進行分裂), 지칠화적황극적위치급통치병주재만물적군주지위(至七火的皇極的位置及統治幷主宰萬物的君主之位). 7. 당종해주장적미분지란위태극지설(唐宗海主張的未分之卵爲太極之說), 장태극비유위계란적원시물질(將太極比喩爲鷄卵的原始物質), 란핵등(卵核等), 단정자여란자상결합(但精子與卵子相結合), 상미진행분열적상태위원시적혼륜지물(尙未進行分裂的狀態爲原始的渾淪之物), 위장분화위음양지처(爲將分化爲陰陽之處), 인차본인인위장기정위태극적상법최위첩절(因此本人認爲將其定爲太極的想法最爲貼切).

• Journal of Korean Association for Spatial Structures
• /
• v.11 no.4
• /
• pp.61-69
• /
• 2011

It is hard to predict the mechanical characteristics of discontinuous stone masonry structures with the use of by the static analysis method, because of irregularity of face stones and also due to randomness of backfill materials. Inversely, one can estimate the mechanical characteristics by comparing the natural frequencies between measured from the field tests and computed from the analytical models. The aim of this paper is to investigate the effectiveness and confidence of the computational modeling method of ancient stone arch bridges in Korea and to find the factors influencing their dynamic characteristics. The results revealed that the rigidity of spandrel walls and backfill materials are the most important factors influencing the natural frequencies of stone arch bridges, which are the critical for the stability of the stone arch structure.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.25 no.8
• /
• pp.1444-1452
• /
• 2001

Textile materials are frequently in contact with surfactant solutions during their manufacturing or finishing processes as well as cleaning processes in use. Liquid wetting, wicking and absorbency of textile materials, and the liquid properties, surface characteristics and pore geometry of textile materials, and the liquie-solid interactions, In this paper, 10 different nonionic surfactants, including Span 20, Twen 20, 40, 60, 80, 21, 61, 81, 65, 85, were used. The surfactants were characterized by their hydrophile-lipophile-balance (HLB) values, structures, and surface tensions. The 0.1g/dL and 1.0g/dL surfactant solutions, which were both above critical micelle concentration (CMC), were used to see the concentration effects on the wetting and absorbency of cotton fabrics. The wetting behavior and liquid retention properties of hydrophobic cotton fabrics with different nonionic surfactant solutions are reported. The contact angles are greatly decreased and the water retention values are greatly increased by adding most of the surfactants studied into the system. The extents of this effects are influenced by the characteristics of surfactants and its solutions. Hydrophilic surfactants which have low number of carbon atoms or unsaturated hydrophobe structures are more effective in improving the wetting and absorbancy of hydrophobic cotton fabrics. The water retention of hydrophobic cotton fabrics has positive relations with $cos{\theta}$, adhesion tension and work of adhesion. The 1.0g/dL surfactant solutions show similar, but slightly improved wetting and absorbency characteristics of hydrophobic cotton fabrics compared to the 0.1g/dL surfactant solutions.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.31 no.2
• /
• pp.123-128
• /
• 1986

The characteristics such as characters of seed, fruit and endosperm, development of embryo, dehisced and germination rate of seeds which harvested at 10 days intervals from 20 days to 60 days after pollination were determined to clarify the optimum time for seed production of ginseng. The sizes of length, width and thickness of fruits, seeds and endosperms investigated on 20 days after pollination were not largely different from those that harvested after 60 days. But the weights of fruits and seeds were increased along with the delay of harvesting time. The seeds which harvested from 30 to 60 days showed comparatively high dehisced and germinated rates, especially 40 days in dehisced rates and 50 days in germinated rates. The embryos were rapidly grown in early stage. Lengths of the embryo on 20 days after pollination were approximately grown to 30 ${\mu}{\textrm}{m}$. And after 30 days pollinated, embryos were not only more rapidly grown to 213 ${\mu}{\textrm}{m}$ but also cotyledon premodia were developed in this time and completely formed after 40 days.