• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.2
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• pp.86-93
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• 2016

Performance tests of a 75-tonf liquid rocket engine turbopump were conducted. The performance of sub-components - two pumps and a turbine - and their power matching were measured and examined firstly near the design speed under the LN2 and kerosene environment. In the real propellant - LOX and kerosene - environment tests, design and off-design performance of turbopump were fully verified in regime of the rocket engine operation. During the off-design performance tests, turbopump running time was set longer than the engine operating time to verify the pump operability and set the pump inlet pressure close to design NPSHr to investigate pump suction capability in parallel. It has been found that developed-turbopump satisfied all of the engine required performances.

• Korean Journal of Agricultural Science
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• v.19 no.2
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• pp.201-237
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• 1992

본(本) 연구(硏究)는 1992년(年) 2월(月)부터 동년(同年) 8월(月)까지 한국(韓國)의 농어촌진흥공사(農漁村振興公社)(RDC)와 말레시아의 KTA기술용역단간(技術用役團間)의 기술제휴하(技術提携下)에 아세아개발은행(亞細亞開發銀行)의 기술협력기금(技術協力基金)에 의(依)한 말레지아북부(北部) Terengganu 농촌개발제(農村開發第)2단계사업(段階事業)의 타당성조사연구(妥當性調査硏究) 결과(結果) 중 말레시아정부(政府)의 경제정책방향(經濟政策方向), 농업개발(農業開發) 및 사업(事業)의 경제적(經濟的) 재무적(財務的) 타당성(妥當性)만을 발췌(拔萃)하여 본(本) 논문(論文)에 수록(收錄)하였다. 본(本) 농촌개발사업지구(農村開發事業地區)는 말레시아의 북동(北東)쪽에 위치(位置)하고 있는 Terengganu State의 Setiu-Besut양(兩) Distict가 포함(包含)되는데 경제적(經濟的)으로 가장 낙후(落後)된 지역(地域)으로 매년(每年) 행사(行事)처럼 찾아오는 홍수(洪水)때문에 농경지(農耕地)를 집약적(集約的)으로 경작(耕作)하지 못함으로써 지역농민(地域農民)들은 빈곤(貧困)에서 벗어나지 못하고 있고 침수기간중(浸水期間中)에는 지역(地域)의 경제활동(經濟活動)은 물론(勿論) 교통(交通)마저 불통(不通)되고 농촌하부구조(農村下部構造)의 손실(損失)은 물론(勿論) 사회경제적(社會經濟的)인 손실(損失)이 크며 Setiu River의 하구(河口)가 침전(沈澱)되어 어선(漁船)의 출입(出入)이 점점(漸漸) 곤란(困難)해지므로써 어민(漁民)들의 생계(生計)에도 위협(威脅)을 주는 지역(地域)이다. 따라서 본(本) 타당성(妥當性) 조사연구(調査硏究)의 근본적(根本的)인 목적(目的)은 농촌(農村)의 빈곤(貧困)을 타파(打破)하기 위하여 (1) 홍수(洪水)를 방지(防止)하고, 배수(排水) 및 관개개선(灌漑改善)을 하며, 하구(河口)를 개발(開發)하여 어민(漁民)들의 생산활동(生産活動)을 돕고 지역주민(地域住民) 및 농민(農民)들의 경제활동(經濟活動) 및 농업생산성(農業生産性)을 제고(提高)시키며 (2) 환경보호(環境保護) 및 관리(管理)를 통(通)하여 지역주민(地域住民)에게 쾌적(快適)한 농촌생활환경(農村生活環境)을 제공(提供)하고 생태계(生態系)의 변화(變化)를 방지(防止)하며 (3) 다각적(多角的)인 영농활동(榮農活動)을 통(通)하여 지역농민(地域農民)의 소득(所得)을 극대화(極大化) 할 수 있는 개발(開發)의 기본구상(基本構想)과 이에 대한 기술적(技術的) 경제적(經濟的) 타당성(妥當性)을 구명(究明)하는 것이다. 본(本) 사업지역(事業地域)의 총면적(總面積)은 9,500ha이며 이는 4,680ha의 기설지구(旣設地區)의 개보수관개사업(改補修灌漑事業)과 500ha의 과수단지(果樹團地), 200ha의 채소단지(菜蔬團地), 500ha의 옥수수단지(團地), 250ha의 엽연초생산단지(葉煙草生産團地), 2,760ha의 오일팜 및 고무나무단지에 소, 염소 및 양(洋)을 사육(飼育)하는 종합적(綜合的)인 농촌개발(農村開發)로서 농가(農家)의 농업소득제고(農業所得提高)에 큰 기여(寄與)를 하게 되며 Setiu강(江)의 유역(流域) 4,090ha에 대한 홍수경감대책(洪水輕減對策)으로 지역주민(地域住民)의 생활안정(生活安定) 및 교통(交通), 관광(觀光), 사회경제적(社會經濟的) 생산활동(生産活動)을 촉진(促進)하는 사업(事業)을 하게된다. 본(本) 사업(事業)의 공사기간(工事期間)은 1993년(年)부터 5개년간(個年間)이며 총사업비(總事業費)는 외화(外貨) 2천만불(千萬弗)을 포함(包含)하여 5천(千) 5백만불(百萬弗)로 추정(推定)되었다. 년간사업수익(年間事業收益)은 사업(事業)의 완전운영기간(完全運營期間)인 2003년(年)을 기준(基準)으로 할 때 15,541백만불(百萬弗)로 추정(推定)되었으며 사업(事業)의 내구기간(耐久期間)은 30년(年)으로서 2023년(年)까지 생산(生産)이 계속(繼續)될 것이다. 본(本) 사업(事業)의 전체재무수익율(全體財務收益率)은 22.49%이며 경제적(經濟的) 수익률(收益率)은 19.30%로 경제적(經濟的)인 타당성(妥當性)이 매우 높음을 알 수 있다. 모든 사업(事業)이 계획(計劃)대로 성공적(成功的)으로 추진(推進)될 경우 사업지역내(事業地域)의 몽리농가(蒙利農家) 4,000호(戶)가 큰 혜택(惠澤)을 보게되고 농촌(農村)의 빈곤수준(貧困水準)(Poverty Line)은 현재(現在)의 36%에서 18%수준(水準)으로 경감(輕減)될 것이 기대(期待)되고 있다.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.3
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• pp.557-568
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• 2005

The aim of this study was to evaluate the resistance to degradation and to compare the wear resistance characteristics of four esthetic restorative materials in an alkaline solution(0.1N NaOH). The brands studied were MetafilCX(Sun medical, Japan) Solitaire 2(Heraeus Kulzer, USA), Composan LCM(Promedica, Germany), DenFil(Vericom, Korea). The results were as follows: 1. The mass loss of each brand was 0.74~7.94% and highest value in Metafil($7.94{\pm}0.39%$). 2. The sequence of the degree of degradation layer depth was in descending order by Metafil, Solitaire 2, DenFil, Composan LCM. There were significant differences between Metafil and the others(p<0.05). 3. The sequence of the Si loss was in descending order by Metafil, Solitaire 2, Composan LCM, DenFil. There were significant differences among the materials(p<0.05). 4. On SEM, destruction of bonding between matrix and filler and on CLSM, the depth of degradation layer of specimen surface was observed. 5. The sequence of maximum wear depth was in descending order by Metafil, Solitaire 2, Composan LCM and DenFil. There were significant differences among the materials(p<0.05). 6. The correlation coefficient between Si loss and degradation layer depth (r=0.491, p<0.05) and Vicker's hardness number and maximum wear depth (r=-0.942, p<0.05) were relatively high. These results indicate that hydrolytic degradation and wear may consider as a evaluation factors of composite resins.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1981.05a
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• pp.3.2-3
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• 1981

This paper was attemped to analize 55 cases of fiberoptic bronchoscopy during period of 3 years from Feb. 1978 till Feb. 1981 in Chung Ang University hospital. The results were as follow; 1) In age distribution; Most common age group was 5th decade (15 cases, 27.2%) and the other age groups showed relatively even distribution. 2) The ratio of male to female was 3 to 1. 3) The chief complaints were presented in following order; cough (52%), hemoptysis(25%), dyspnea(23.6%), chest pain(18%), chest disomfort(9%). 4) Direct smear of bronchoscopic aspiration material; Not found 33 cases (60%) were most common finding. In the founded bacteria Gram positive cocci 2 cases (3.6%), Gram negative cocci 2 cases (3.6%), Gram positive bacilli 1 cases (1.8%), Gram negativebacilli 2 cases (3.6%), mixed form 15 cases(27.2%) were presented. 5) Bacterial culture of bronchoscopic aspiration material; No growth 28 cases (50.9%) were most common finding. In the bacterial growth, alpha hemolytic streptococci 10 cases (18.2%), Neisseria group 7cases(12.7%), Klebsiella 2 cases (3.6%), Pseudomonas 2 cases (3.6%), mixed culture 6 cases (10.9%) were presented, 6) The diagnosis of bronchoscopic appearance, laboratory exam., and pathologic exam. of biopsed specimen were 21 cases (38.1%) primary carcinoma of bronchus, 8 cases (14.5%) pulmonary tuberculosis, 7 cases (12.7%) bronchitis in orders.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.3
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• pp.21-29
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• 2016

In this paper, we developed a flexible transparent capacitive pressure sensor which can recognize X and Y coordinates and the size of force simultaneously by sensing a change in electrical capacitance. The flexible transparent capacitive pressure sensor was composed of 3 layers which were top electrode, pressure sensing layer, and bottom electrode. Silver nanowire(Ag NW)/poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) hybrid film was used for top and bottom flexible transparent electrode. The fabricated capacitive pressure sensor had a total size of 5 inch, and was composed of 11 driving line and 19 sensing line channels. The electrical, optical properties of the Ag NW/PEDOT:PSS and capacitive pressure sensor were investigated respectively. The mechanical flexibility was also investigated by bending tests. Ag NW/PEDOT:PSS exhibited the sheet resistance of $44.1{\Omega}/square$, transmittance of 91.1%, and haze of 1.35%. Notably, the Ag NW/PEDOT:PSS hybrid electrode had a constant resistance change within a bending radius of 3 mm. The bending fatigue tests showed that the Ag NW/PEDOT:PSS could withstand 200,000 bending cycles which indicated the superior flexibility and durability of the hybrid electrode. The flexible transparent capacitive pressure sensor showed the transmittance of 84.1%, and haze of 3.56%. When the capacitive pressure sensor was pressed with the multiple 2 mm-diameter tips, it can well detect the force depending on the applied pressure. This indicated that the capacitive pressure sensor is a promising scheme for next generation flexible transparent touch screens which can provide multi-tasking capabilities through simultaneous multi-touch and multi-force sensing.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.2
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• pp.1-14
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• 2012

The purpose of this study is to derive a desirable riverfront construction plan to me for the activities of citizens through the evaluation and analysis of the urban riverfront space from the perspective of universal design. Therefore, previous studies were examined in order to induce evaluation tools that bhve been grafted from the universal design concept; in addition, a field survey was conducted in Shincheon, Daegu, which was selected as the study target, in order to induce problems and improvement directions from the perspective of universal design. The major results can be summarized as follows. (1) In the 'fairness' aspect, all the items such as installation of integrated functional signage, showing pictures, symbols, foreign language signs, and restroom entrances signage were determined to be 'All Unsuitable' for all sections; and therefore, it is necessary to improve the fairness of usage for everybody. (2) In the 'Functionality(Usability)' aspect, all items such as installation of bicycle paths beside access roads, installation of integrated functional signs, and night light signs were determined to be 'All Unsuitable' for all sections; therefore, it is necessary to improve the functionalities of these facilities. (3) In the 'Convenience' aspect, all items such as the installation of bicycle parking areas, continuous rest facilities, and back and ann support(handles) at resting facilities were determined to be 'All Unsuitable' for many sections; therefore, it is necessary to improve these facilities for the convenience of usage. (4) In the 'Information(Recognizability)' aspect, all items such as showing pictures, symbols, foreign languages and installation of night light signs, and restroom entrances signage were determined to be 'All Unsuitable' for all sections; therefore, it is necessary to improve the recognizability to minimize misunderstandings and confusion. (5) In the 'Safety' aspect, all items such as the installation of safe pedestrian paths in parking areas, using anti-slip and shock absorption materials on restroom floors, and the continuous installation of pedestrian paths that are separate from bicycle paths were determined to be 'All Unsuitable' for all sections; therefore, it is necessary to improve the safety to prevent accidents. (6) In the 'Amenity' aspect, access roads, parking areas, hygiene facilities, convenience facilities, and waterside facilities for many sections were determined to be 'All Unsuitable'; therefore, it is necessary to conduct more concentrated hygiene management. (7) In the 'Accessibility(Mobility)' aspect, all items such as the installation of safe pedestrian paths in parking areas, and continuous pedestrian paths that are separate from bicycle paths were determined to be 'All Unsuitable' for all sections; therefore, it is necessary to improve the accessibility to provide safety and convenience. (8) In the 'Durability' aspect, access roads, parking areas, rest facilities, convenience facilities, fitness facilities, and waterside facilities were determined to be 'All Unsuitable' for many sections, therefore, it is necessary to improve sunken or damaged areas by inspecting facilities by section.

• Journal of Conservation Science
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• v.31 no.1
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• pp.37-46
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• 2015

In the case of adhesives & restoration agents currently being used for the preservation treatment of ceramics and earthenware, epoxy type, cellulose type and cellulose type are mainly being used. However, they are showing various problems such as re-detachment from severe contraction, color change from yellowing, work inconvenience of staining on tools and hand during usage and irreversibility. For the purpose of solving the issues of yellowing and irreversibility of epoxy resin being used to restore ceramics, urethane synthetic resin with low yellowing excellent reversibility has been developed in this study. The adhesive strength of urethane resin that has been developed has excellent properties with 2.07MPa for undiluted solution, which is 1.5 times higher than that of existing material EPO-$TEK301^{(R)}$ 1.21MPa. The result of workability measurement showed that the wear rate of urethane resin (in Talc 50wt%) was 1.09%, which was somewhat higher than that of existing material Quick $Wood^{(R)}$ (1.02%). In addition, its wear rate is two times higher than that of $EPO-TEK301^{(R)}$ (0.41%) and $L30^{(R)}$ (0.39%), thereby showing an advantage in its forming process compared to existing materials. As for the advantage of urethane resin of reversibility experiment, 12 hours after acetone, ethyl alcohol deposition, urethane resin and filler talc were dissolved 100% while showing powdering phenomenon. Compared to 0% reversibility of existing epoxy resin, it has much superior reversibility. The result of UV rays experiment to evaluate its durability showed that ${\Delta}E^*ab$ color change value based on undiluted solution of urethane resin was 2.76 before & after UV rays exposure, which was a decrease by about 7-20 times compared to that of existing resin, thereby minimizing the issue of heterogeneity.

• Economic and Environmental Geology
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• v.47 no.6
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• pp.563-569
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• 2014

Ruby is one of the most favor colored gem, for beautiful red tone, be high in scarcity value. However, rubies with high quality are produced in restricted regions, such as in Thailand, Sri Lanka, Myanmar, and Tanzania etc., and they have been gradually exhausted by mining for a long period. Therefore, improving qualities of low level rubies with various treatments is arising an alternative way to obtain better rubies. Gemological and mineralogical properties of the natural ruby from Tanzanian were studied with heat treatments. Those characteristics were compared between only heat and adding flux materials under heating. Tanzanian raw rubies were applied a heat treatment ($1,600^{\circ}C$ for 6 hours). However, chromameter and UV-Vis analyses found that a simple heat treatment is inappropriated for the Tanzanian ruby. Although $Cr^{3+}$ containing for red color in the ruby increased with heat treatment, the ruby displays dark medium red because of Fe in the ruby as a form of $Fe_2O_3$. The low transparency after heat treatment is attributed to the recrystallization of $SiO_2$ which has a low melting point. Chromameter confirmed adding Pb-containing flux under heating greatly improves the clarity and color of Tanzanian rubies with micro-fractures and cavities on the surface. EMPA results show that Pb as an additive fills the cavities and cracks on raw Tanzanian rubies during the heat treatment. As a rewult of it, the quality of the Tanzanian ruby raw dramatically improved. These results indicate that the heat treatment with an additive (Pb in this study) is an effective way to obtain better quality of the Tanzanian ruby. Consequently, this study suggests a suitable method to improve the properties of the Tanzanina ruby. The result of this study would provide useful information to upgrade the qualities of similar gem stones such as corundum and sapphire.

• Korean Journal of Agricultural and Forest Meteorology
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• v.2 no.4
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• pp.156-166
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• 2000

This study was carried out to provide the information on seasonal variations of water content under highway asphalt pavements which influence on the dynamic behaviour and durability of pavements, and to assess the correlation between water content and soil or meteorological factors. Total eight sites for water content measurement which included fives sites in Kyungbu, two sites in Honam, and one site in Youngdong Highway were selected considering the variations in geology, topology and meteorology factors over all the country. Water contents under asphalt pavements were measured up to 170 cm depth every two week for total 13 months of August 1992 through September 1993 using neutron moisture meter(CPN-503DR). The range of water content ($\theta$$_{w}$) at the upper soils of above 50 cm depth was 7~12% and was not quite different regardless of sites, except for Iseo site. However, soil water contents below 60 or 70 cm depth were significantly different between the measurement sites, that is, the lowest water content was 5% at Kyungsan site and the highest water content was 20% at Iseo site. For all the sites, seasonal variations in water content during the experimental period were little, their range was within only 1 to 4%. Seasonal variations of water content in original or cutting area, which were 4% more or less, were slightly larger than in bedding areas, which were below 2%. Water contents under asphalt pavements had statistically significant positive correlations with silt and clay content in soil, but there were little correlations between water content and meteorological factors such as precipitation, relative humidity, mean air temperature, and wind velocity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4602-4609
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• 2013

In summer and winter, the difference between the temperature during the day and that during the night is high, which leads to various problems during concrete placement, such as cracks and defects in the concrete as well as low durability and strength. Although nuclear power plant concrete is widely used for placement in all seasons, particular attention must be paid to its quality during the summer. Therefore, we evaluated the effects of a cooling method for mixing water, which is a commonly used hot weather precooling method, and the use of a retarder, on the characteristics of Nuclear Power Plant concrete. In the cooling method for mixing water, cold water at 5 was used, with 50% of the water content consisting of ice flakes. The effects of using a retarder were evaluated by reviewing the characteristics of the cement at the unset stage and after hardening. To evaluate the characteristics of the unset cement, we measured the slump, air volumes, setting times, and pressure strengths after hardening. Furthermore, we measured the heat of hydration at different temperatures; the loss of heat was minimized using insulation. Both the slump time and the complete ageing time of the air volume were found to be 120 min at $20^{\circ}C$ and 40 min at $40^{\circ}C$. In the case when the cooling method for mixing water was used and in the case when a retarder was used, the initial and final sets by penetration resistance were delayed, and the delay decreased with increasing air temperature. For the heat of hydration, the cooling method for mixing water not only lowered the maximum temperature but also delayed its attainment. However, the use of a retarder had no effect on the maximum temperature. Moreover, in the early ages (e.g., 3 and 7 days), the pressure strength of the concrete was lower than that of plain cement. However, the strength of 28-day concrete met the standard construction specifications.