• 기술사
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• 제43권6호
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• pp.27-30
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• 2010

Gyeongbu high-speed railway project which comprises the construction of the new line with 417.5km between Seoul and Busan is one of the biggest national projects with approx. 20-trillion-won project cost. The construction was started in June 1992 and afterward phase I (between Seoul and Daegu) was opened in April 2004 and phase II (between Daegu and Busan, 169.5km) is scheduled for opening in the end of October 2010. It is assured that the opening of the entire sections of Gyeongbu high-speed railway will significantly increase productivity and efficiency by improving the land utilization with the promotion of personal and material exchanges induced by the reduction of travel time between regions. Especially, Gyeongbu high-speed railway will be the opportunity to boost speed-up of Korea railway.

• 통상정보연구
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• 제7권3호
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• pp.97-111
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• 2005

This paper object is application of electronic Customers Relationship Management(e-CRM) for buyer This paper focuses on the possibility of the adaption of Escrow system in Local L/C opening and payment. The purposes of this study are to obtain efficiency and stability of Local L/C and to provide opportunity to accept trust of the transaction parties. The results of the study show that Escrow system is recommended when Local L/C opened, because Escrow system has the following merits: (1) Open system of internet can be used to Local L/C process. (2) Transaction process of Escrow system is very simple. (3) One stop transaction can be applied to all the process of local L/C.

• Macromolecular Research
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• 제14권4호
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• pp.424-429
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• 2006

The synthesis of a series of poly(POSS-NBE-b-MTD) copolymers was successfully accomplished, taking advantage of sequential, ring-opening, metathesis block copolymerization using $RuCl_2(=CHPh)(PCy_3)_2$ catalyst. By using cyclopentyl-POSS-norbornene (POSS-NBE) monomer as the first block in the block copolymer, living poly(POSS-NBE) with controlled molecular weight and narrow molecular weight distribution was produced. Then, poly(POSS-NBE-b-MTD) copolymers were successfully prepared, in which sequential monomer addition of methyltetracyclododecene (MTD) to the living poly(POSS-NBE) chain ends was utilized to achieve quantitative crossover efficiency. Characterization by $^1H$ NMR spectroscopy and GPC confirmed the high definition and structural integrity of the poly(PO$S-NBE-b-MTD) copolymers. Thermal properties-and morphologies of the POSS-containing block copolymer nanocomposites were also investigated by using thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and wide-angle X-ray scattering (WAXS).

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.362-366
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• 1987

The amount of inflowing Air into the boiler has controlled by manipulating the opening of valve, damper and vane, as fan operated by induction motor operats at constant speed, but these control methods are not efficient. Thus VVVf(Variable Voltage Variable Frequency) control of fan has selected to improve efficiency and to acquire power savings. Control system of Air Flow is affected by nonlinearity caused by load variation, vane opening, etc. The analysis of control parameter causing nonlinearity is needed to acquire optimal control and excellent transient response. This paper provides modeling of boiler with various load conditions and vane opening, and analysis of this system.

• Macromolecular Research
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• 제17권9호
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• pp.651-657
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• 2009

This study examined the optimum compositions of binder, photo-acid generator (PAG) and sensitizer for the cationic ring opening polymerization of 1,3-bis[2-(3-{7-oxabicyclo-[4.1.0]heptyl})]-tetramethyldisiloxane in the presence of polydimethylsiloxane with four epoxide moieties as a co-monomer. When diffractive efficiency (DE) values were compared quantitatively to analyze the effect of the binder on holographic photopolymerization, DE was affected by the viscosity of the binders and miscibility with the monomer mixture. Extremely low DE values were observed when the immiscible dimethyl silicone was used as a binder. Therefore, methylphenyl silicone, which is miscible with the monomer mixture, was used as the binder for further studies. The optimal conditions were a binder viscosity between 250 to 390 cP, and contents of the binder, PAG, and sensitizer were 75-125 wt%, > 6 wt% and 0.05 wt% to the total monomer mixture, respectively.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.140-141
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• 2022

CFD analysis was performed to analyze the temperature distribution of the inner space of the curing house according to blocking the opening of the gang-form with a tent in case of concrete pouring and heat curing of the apartment house during the winter season. If the gang-form opening is closed with a tent during internal heating using a hot air blower in the winter, the internal temperature rises compared to the non-reserved due to air-tightness of the curing spaces, and uniform temperature distribution can be ensured. In addition, it is possible to increase curing efficiency by reducing the amount of heat supplied and shortening the heating time.

• 수산해양기술연구
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• 제55권1호
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• pp.7-19
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• 2019

This study was conducted in order to improve opening efficiency of the miniaturized small-scale net for anchovy boat seine gear to reduce the fleet size. Field experiment was performed to observe geometry of nets by catcher boats. When the distance between the two ships was 150, 300 and 450 m and the speed of towing nets was 0.6, 0.9, and 1.2 kt, the vertical opening and actual opening of each part of the miniaturized small-scale net was as follows: the front part of the wing net, 6.8-9.5 m, 45-63%; the middle part of the wing net, 16.1-30.7 m, 34-65%; the entrance of the inside wing net, 21.6-41.2 m, 44-84%; the square and bosom, 17.4-34.0 m, 38-75%; the entrance of the body net, 16.5-29.4 m, 36-64%; the entrance of the bag net, 14.5-21.9 m, 70-106%; the flapper, 6.7-7.7 m, 81-83%, and the end of the bag net, 8.6-10.9 m, 64-81%. The tension of towing nets was measured to be 2,734-6,812 kg approximately, which indicates that the fleet can tow nets with 350 hp, the standard engine horse power. The fishing operation time was shortened comparing to existent net with the large-scale buoy attachment operation. It was also possible to operate the ship without fish detecting boat.

• 터널과지하공간
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• 제27권1호
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• pp.1-11
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• 2017

국내 지하 석회석 광산은 대부분 대단면 갱도로 개발되고 있으며 갱내통기는 주요 선풍기에 의한 통기방식보다는 자연통기 및 국부통기에 의존하고 있다. 국부통기는 국부선풍기와 풍관을 이용한 급배기 통기방식을 적용하고 있으나 대단면 갱도 특성과 갱내 굴진 운반장비의 디젤화에 따라 소요통기량이 대폭 증대하여 통기의 효율 및 경제성 확보가 주요과제로 대두되고 있다. 본 연구에서는 대단면 갱내 작업장 국부통기를 위한 선풍기 용량 최적화를 위하여 축류식 및 프로펠러 선풍기를 개발하여 갱내 승압력 및 통기효과를 비교 분석함을 목적으로 한다.

• 수산해양기술연구
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• 제57권4호
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• pp.271-282
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• 2021

This study aims to understand the opening efficiency of the finless porpoise escape guide net by the type of extension net that is the part to which the escape guide net is attached in stow net. To this end, extension nets were manufactured in full size and the net mouth area and towing tension were investigated according to the towing speed (0.2, 0.4, 0.6 and 0.8 m/s) and the type of extension net (25 mm net and raschel net) in the water tank. As a result, the net mouth area of the guide net was larger when the raschel net was used for the extension net than when the 25 mm net was used under all towing speeds. In addition, regardless of the type of extension net, the net mouth area reached about 80% of the maximum value at a towing speed of 0.4 m/s. In the field, fishing operation of stow net is performed only when the current speed is above 0.4 m/s. Therefore, the speed of 0.4 m/s was confirmed as a meaningful value to determine whether it is possible to operate. As a result of analyzing the relationship between the net mouth area of the guide net and the towing tension, it was confirmed that the difference in the net mouth area of the guide net according to the type of the extension net was due to the difference in the solidity ratio.

• Journal of Pharmaceutical Investigation
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• 제30권4호
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• pp.253-258
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• 2000

In order to design the oral vaccine delivery system, we prepared the alginate micro spheres containing GFP (green fluorescent protein) as a model drug by spray method. To optimize the preparation conditions of microspheres, we investigated the effects of various parameters including nozzle pressure, nozzle opening angle, and concentrations of sodium alginate and calcium chloride. The prepared microspheres were evaluated by measuring their sizes, loading efficiency, and morphology. The particle size of microspheres was affected by the concentration of sodium alginate and calcium chloride, nozzle pressure, and nozzle opening angle. As the concentration of sodium alginate increased, GFP loading efficiency and particles size of microsphere also increased. However, it was observed to be difficult to spray the sodium alginate solution with concentration greater than 1.5% (w/v), due to high viscosity. The pressure over $3\;kgf/cm^2$ didn't affect the size of particles. As a result, the spraying method enabled us to prepare microspheres for oral vaccine delivery system. In this study, microspheres prepared with 1% (w/v) sodium alginate had greater loading efficiency and better spherical shape.