• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 추계 학술논문 발표대회
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• pp.79-80
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• 2017

This study examined the effect that the amorphous metallic fibers had on the static mechanical properties and the impact resistance of cement composites to those of hooked steel fibers. The hooked steel fiber exhibited pull-out from the matrix after the peak flexural stress was attained, while the amorphous metallic fiber was not pulled out from the matrix, but was instead cut off. In terms of impact resistance, the amorphous metallic fiber reinforced cement composite was found to be more effective at resisting cracking than the hooked steel fiber reinforced cement composite. Therefore, amorphous metallic fiber should be used in fiber reinforced cement composite materials, and for structural materials, and for protection panels.

• 대한기계학회논문집
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• 제13권4호
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• pp.708-716
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• 1989

본 연구의 목적은 고속도 카메라로 촬영된 순간사진들로부터 액주면의 파장, 진폭, 파의 진행속도 및 교란의 성장속도 등을 측정하여 액주의 분열에 미치는 기류 및 액량의 효과를 구하였고, 또 이것을 선행 연구자들의 이론 및 실험과 비교분석하여 액주의 분열 기구를 밝히는 데 있다.

• 한국전기전자재료학회논문지
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• 제20권6호
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• pp.491-495
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• 2007

This paper has demonstrated the electrical properties of SiGe pMOSFETs fabricated on both bulk-Si and PD SOI substrates. Two principal merits, the mobility increase in strained-SiGe channel and the parasitic capacitance reduction of SOI isolation, resulted in improvements in device performance. It was observed that the SiGe PD SOI could alleviate the floating body effect, and consequently DIBL was as low as 10 mV/V. The cut-off frequency of device fabricated on PD SOI substrate was roughly doubled in comparison with SiGe bulk: from 6.7 GHz to 11.3 GHz. These experimental result suggests that the SiGe PD SOI pMOSFET is a promising option to drive CMOS to enhance performance with its increased operation frequency for high speed and low noise applications.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2004년도 춘계학술대회
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• pp.303-306
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• 2004

참멍게의 체액세포로부터 산추출 후, 조 추출물에서 천연항균소재를 개발하기 위해 먼저 멍게 조 추출액을 직접 Tricine-SDS PAGE를 통하여 주요 펩타이드들의 분자량의 범위를 살펴본 결과 6kDa 이하의 분자량의 펩타이드들이 다량 존재함을 알수 있었다. 펩타이드들의 size별 항균활성을 알아보기 위해 여러 사이즈의(100, 50, 30, 10 kDa)의 한외여과만으로 여과하여 그 여과액들의 specific 활성을 알아본 결과 여과막의 cut-off size에 상관없이 거의 인정한 specific activity를 가짐을 알 수 있었다. 멍게 조 추출액의 여러 미생물에 대한 항균 스펙트럼을 알아보기 위해 E.coli, P. aeruginosa, S. typhi, V. parahaemolyticus, L. monocytogenes, B. sutillus, S. aureus, S. mutans 균주들을 $10^5 CFU/ml$로 부터 4log 감소시키는 농도를 측정한 결과 각각 200, 50, 60, 10, 25, 30, 100, 100ppm 농도였으며, 대표적 상용화 항균 펩타이드인 Nisin과의 항균활성 비교 결과 비슷하거나 월등히 뛰어난 결과를 보여주었다. 또한 추출액의 열안정성을 측정하기 위해 $100^{\circ}C$에서 10분간 가열한 후 원액과의 항균력의 차이를 Radial diffusion assay로 알아본 결과 항균력의 차이가 거의 없음을 알 수 있었다.

• Korean Membrane Journal
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• 제3권1호
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• pp.17-23
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• 2001

Polyethersulfone (PES) and cellulose acetate (CA) ultrafiltration (UF) membranes having different molecular weight cut-off values were prepared by immersion precipitation method by changing the compositions of easting solution. Egg white solution was concentrated to volume concentration ratio 4 in tubular UF with membranes made of moderately hydrophobic PES and hydrophilic CA. The process Parameters such as pressure and fluid velocity were controlled in order to apply successfully for egg white solution and to investigate the pressure dependency. The resistance values were measured to investigate the fouling and concentration polarization effect on membrane performance. During concen- tration of egg white solution by UF, the fouling layer appeared to contribute little resistance to flux compared to that of polarized layer.

• Membrane and Water Treatment
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• 제9권2호
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• pp.87-94
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• 2018

The interactions of water soluble polymers with dye are studied by ultrafiltration using a molecular weight cut off of 10 KDa regenerated cellulose ultrafiltration membrane. Two water-soluble polymers, namely Poly (Sodium-4 Styrenesulfonate) (PSS) and Poly (Vinyl Alcohol) (PVA) were selected for this study. The effects of process parameters, such as, polyelectrolyte concentrations, transmembrane pressure, ionic strength and pH of solution on dye retention and permeation flux were examined. PSS enhanced ultrafiltration achieved dye retention as high as 99% as a result of complexation between polyanion containing aromatic groups and cationic dye. This result was confirmed by the red shift. The retention of dye decreases as the salt concentration increases, a high retention was obtained at pH above 4. However, in case of PVA, relatively low retention (50%) was observed. Ionic strength and pH has no significant effect on the removal of MB. The permeate flux depended slightly on polyelectrolytes concentrations, transmembrane pressure, salt concentration and pH.

• 한국가시화정보학회지
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• 제18권3호
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• pp.77-83
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• 2020

A uniflow cyclone has simple structure with a single channel in one direction. The one directional particle removal enables the uniflow cyclone to have compact size and low pressure drop. However, it has low collection efficiency compared to conventional cyclones. In this study, the effect of primary geometry on the performance of a uniflow cyclone with swirl vane is numerically investigated for the design of high performance uniflow cyclone. It is found that as the vortex finder diameter is increased, the pressure drop and the collection efficiency are decreased. Also, the same trend is predicted when the vortex finder height is increased. The best collection efficiency is predicted to be obtained when the vortex finder height is equal to the diameter of a cyclone. Reducing the body height by half will increase the pressure drop by 41%. When the body height is decreased, the collection efficiency is first increased and then decreased. The best collection efficiency is obtained when the body height is 4~5 times the cyclone diameter. Overall, the particle collection efficiency is highest when the Dν/D is equal to 0.3. But, the pressure drop is as high as 1592 Pa. Considering both collection efficiency and pressure drop, the best design is when Dν/D, Hν/D, and Hb/D are equal to 0.5, 1, and 5, respectively.

• Nuclear Engineering and Technology
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• 제54권8호
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• pp.2871-2876
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• 2022

The sensitivity of polymer-based capacitive relative humidity (RH) sensors after irradiation with neutrons, electrons and protons was measured. Degradation consists of the decreasing of the upper RH limit that can be measured. At the same time, low RH-level sensitivity is almost stable. After 30 krad of absorption dose, RH cut off is equal to 85% of max value, after 60 krad-40%. Degradation reduces after annealing which indicates high radiation sensitivity of the internal circuit in comparison to RH-sensing polymer film.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.301-302
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• 2023

In this study, we aimed to identify changes in fire resistance according to the type of sleeves used for pipe penetrations and to examine their accreditation of fire resistance performance and use them as basic data. The test results of fire resistance according to the type of sleeve used in non-metallic pipe facilities showed that the temperature on the support side was higher for sleeves with higher thermal conductivity. For the temperature on the surface of the pipes, in the case of galvanized steel plates, steel pipes, and structures without sleeves, the highest temperature was observed after the expansion of the firestop material for 46 to 53 minutes and then decreased. PVC sleeves showed a steady increase in temperature until 53 minutes, after which the temperature did not increase further. In addition, for non-metallic pipes, the effect of the type of sleeve on fire resistance is considered to be insignificant because the lower part (heating direction of the furnace) under the support structure is cut off to block the heat during the two-hour fire resistance test.

• 한국지반공학회논문집
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• 제21권1호
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• pp.43-50
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• 2005

고압분사주입공법은 지반개량, 차수벽, 흙막이벽, 기초 보강말뚝 등에 사용되고 있다. 고압분사주입공법은 사질토지반에 대해서는 지수목적으로, 연약한 점성토 지반에서는 지반강화를 위하여 사용되고 있다. 그러나 현재 국내에 적용되고 있는 경우의 대부분은 지반조건에 따른 강도증가 효과를 경험적으로 파악하여 설계에 적용하고 있는 실정이고 이에 대한 많은 연구가 진행되고 있다. 본 연구에서는 고압분사주입공법의 지반교란에의 효율성을 증대시킬 목적으로 공동현상(cavitation) 이론을 응용하고자 하였다. 그리고 이를 정량적으로 분석하기 위하여 공동현상(cavitation)을 적용한 경우와 적용하지 않은 경우에 대해 지반조건, 주입압력 및 주입시간 등을 변화시켜가며 점성토 및 사질토 모형지반에 대하여 그라우팅을 실시하였다. 시험결과 공동현상(cavitation)을 적용한 경우 점성토 및 사질토 지반 모두 좋은 결과를 보여, 실제 공법에 적용가능성이 높은 것으로 나타났다.