• Journal of Advanced Marine Engineering and Technology
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• v.36 no.4
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• pp.484-489
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• 2012

The objective of this work presented here was focused on analysis of particulate matter and nitrogen oxide characteristics in ESC test mode from heavy-duty diesel engine installed on-road vehicles applicable to prime propulsion engine for marine vessels. The authors confirmed that a large quantity particulate matter were emitted in high power density condition, nitrogen oxide characteristics were dependent on exhaust gas temperature. Particulate matters were reduced by 1/100~1/1,000 times in post DPF with test modes but filtration efficiency was decreased in the engine power fluctuation. In the case of the high speed and power condition, the exhaust level of particulate matters was increased according to increment of temperature of gas flowing into DPF. The orders of magnitude for particle concentration levels from the analysis of size distribution of particulate matters of test engine was different. Both emitting nano-sized particles below 100nm regardless of DPF and non-DPF.

• Korean Journal of Food Science and Technology
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• v.27 no.6
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• pp.839-844
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• 1995

Appropriate types and concentrations of starch-based fat replacers which are low-pH stable, shear resistant and heat stable were selected to develop reduced-fat mayonnaise without affecting taste, texture and emulsion stability. Four kinds of commercial fat replacers [Neutral DR (DR), Stellar 100X (SX), Sta Slim 150 (SS) and N-Lite L (NL)] were thermally activated after appropriately hydrated and applied to mayonnaise formulation. For each fat replacer, eight recipes having various ratios of soybean oil/fat replacer(95/5 to 60/40) were formulated and compared with standard formulation(100% soybean oil) using rheological and sensory evaluations. All tested starch pastes showed pseudoplastic behavior, time-dependent thixotropic gel characteristics. The increasing order of pseudoplasticity and yield stress was RM, NL, SS and ST. The hardness and adhesiveness of each fat replacer-added mayonnaise was increased in the same order as above. Formulated mayonnaise which contained higher ratio of fat replacer showed lower values in hardness and adhesiveness. ST at up to 25% oil replacement exhibited the highest oil replacing ability among four replacers. ST-added mayonnaise also exhibited the highest sensory score and emulsion stability among all products including standard formula. The high sensory score in spreadability of RM-added mayonnaise well reflected the consistent index of RM paste. Use of fat replacers reduced oily odor and greasy aftertaste of mayonnaise.

• Journal of Sensor Science and Technology
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• v.11 no.2
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• pp.102-110
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• 2002

The chemical and mechanical characteristics of a new surface modifier, dichlorodimethysilane (DDMS, $(CH_3)_3SiCl_2$), for stiction-free polysilicon surfaces are reported. The main strategy is to replace the conventional monoalkyltrichlorosilane(MTS, $RSiCl_3$) such as octadecyltrichlorosilane (ODTS) or 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS) with dialkyldichlorosilane (DDS, $R_2SiCl_2$) with twit short chains, especially DDMS. DDMS, with shorter chains in aprotic media, rapidly deposits on the chemically oxidized polysilicon surface at room temperature and successfully prevents long cantilevers of 3 mm in length from in-use as well as release stiction. DDMS-modified polysilicon surfaces exhibit satisfactory hydrophobicity, long term stability and thermal stability, which are comparable to those of FDTS. DDMS as an alternative to FDTS and ODTS provides a few valuable advantages; ease in handling and long-term storage in solution, low temperature-dependence and low cost. In addition to the new modifier molecule, the simplified process of direct release right after washing the modified surface with isooctane was proposed to cut the processing time.

• Journal of Energy Engineering
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• v.18 no.2
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• pp.108-113
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• 2009

An experimental study of jet impingement on aluminum foam mounted on the surface with constant heat flux is conducted with the presentation of the heat transfer rate measured when jet impinges normally to a flat plate. Effects of pore density, foam thickness and Reynolds number on the heat transfer are analyzed. Experimental results show that the significant enhancement in Nu is obtained when the aluminum foam is mounted on the heated plate and that the increase in the heat transfer due to the porous material insertion is dominated by both the increase in the heat transfer area and the decrease in the momentum flux resulted from the pressure drop.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.489-489
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• 2013

AF 코팅은 유리나 플라스틱과 같은 기재 표면을 특수 처리하여 지문과 같은 오염물질의 부착방지와 오염물질이 부착되더라도 쉽게 제거 가능하도록 하는 기술이다. 전자, 자동차, 건축, 섬유, 철강분야 등에 활용 가능한 중요기술로 박막의 발수 발유 기능을 부여하는 표면처리 기술이고, 코팅방법에는 진공증착, 스핀코팅, 딥코팅, 플로우 코팅, 스프레이 코팅 등이 있으며, 경화 방법이나 접촉각 등의 특성이 반영된다. 터치패널 등의 지문부착방지 기술은 불소계와 비불소계 재료로 구분할 수 있지만 지문을 쉽게 지울 수 있고, 오염 방지 기능과 내구성이 있으며, 우수한 광학특성을 유지하는 것이 과제라 할 수 있다. 그리고 항균성을 부여하는 기술도 개발되고 있다. 이런 터치패널의 강화유리에 AF 코팅한 제품은 핸드폰 글래스에 처음 적용하면서부터 실생활에 도입이 시작되고 있다. 이러한 AF 코팅을 스퍼터링 법을 이용하여 증착 시켰다. 기존에는 E-beam을 이용한 증착 방식이 주를 이루었지만, 스퍼터링 법을 이용함으로써 박막의 균일화 및 대량생산이 가능해졌다. 따라서 이 연구에서는 기존의 E-beam 방식과 sputtering 공정 중 ion source에 의한 전처리의 유무에 따른 박막의 특성을 비교하였다. 내부식성, 내마모성 시험을 거친 후, 접촉각을 측정하여 알아보았으며, 박막의 건전성 및 균일성은 FE-SEM을 이용하여 관찰하였다. 실험용 장비가 아닌 실제 생산장비인 직경 1,400 파이의 장비를 이용하여 증착하였으며 염수분무 및 내마모 시험 후, 기존 접촉각의 ${\pm}5^{\circ}$ 내외임을 확인 할 수 있었고, 박막의 건전성 또한 뛰어남을 알 수 있었다.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.141.2-141.2
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• 2016

디스플레이, 센서 등 전자소자는 소형화 단계를 지나 인체 부착형 소자로의 발전을 요구하고 있다. 인체 부착을 위해서는 민감한 피부에 장시간 부착시 무해성과 탈부착의 자유로움이 요구되기에 기존의 화학물질을 활용한 접착 방식에서 개코도마뱀 또는 딱정벌레 발바닥에서 영감을 얻은 자연모사형 건식 접착 방식에 대한 연구가 활발하게 진행되고 있다. 폴리머를 이용하여 자연모사형 마이크로/나노구조 형성은 기계적으로 가공된 금형 몰딩과 후처리를 통한 매우 복잡한 공정이 요구된다. 본 연구에서는 이러한 복잡한 공정을 단순화하기 위해서 폴리머 소재에 플라즈마를 활용한 나노구조를 형성하는 방법을 소개하고자 하며, 건식 접착용 폴리머 소재(PMMA, PDMS)에 따른 표면구조 변화와 표면에너지 변화에 대한 연구를 수행하였다. 플라즈마 표면처리를 위해서 본 연구실에서 자체 개발한 선형이온소스를 활용하였으며 입사에너지, 노출시간, 사용가스에 따른 표면형상 변화를 주사전자현미경을 활용하여 관찰하였다. 또한 처리조건에 따른 표면에너지 변화를 확인하기 위해 물접촉각 변화를 측정하였다. PMMA는 입사에너지, 노출시간이 증가함에 따라 쉽게 나노기둥구조가 형성되었으나, 과도한 입사에너지 또는 노출시간에서는 표면구조가 에칭되면서 무너지는 것이 관찰되었다. 또한 PDMS는 동일한 조건에서 주름구조 형태를 보였으며 노출시간이 증가할수록 주름구조의 간격이 늘어남을 확인하였다. 본 연구 결과를 통해 나노 구조를 쉽게 제어할 수 있는 PMMA가 피부 부착형 접착 패치에 응용이 가능할 것으로 기대된다.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.408-411
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• 2010

본 논문에서는 의약품, 음료수병 등 액체용기에 부착이 가능하며, 주변 유전체에 의한 성능열화가 적고 소형으로 바코드를 대신하여 용기에 부착이 가능한 플렉시블 RFID 특수태그 안테나를 제안하였다. 제안된 태그 안테나는 PET 기판 위에 미앤더 기법으로 제작되어 제작 및 대량 생산에 용이하며, 범용 RFID의 사용주파수 (860~960MHz)를 만족시키고, 주변 유전물의 영향으로 인한 성능변화를 최소화할 수 있도록 설계하였다. 제안된 태그 안테나는 본체 중앙부에 T 정합회로를 사용하고 미앤더 구조와 직선 구조의 보조선로 2개를 본체 상단에 삽입하여, 캐패시티브 결합을 이용해 태그칩과의 임피던스 공액정합이 쉽게 이루어지도록 하였다. 또한 2개의 보조선로가 각각 다른 부착물체의 유전율에 상호 보완적으로 전류를 유기시 키도록 하여 주변 유전 물질의 영향에 의한 반사손실을 만족하도록 하였다. 본 태그의 성능은 송신출력 20dBm, 안테나 이득 6dBi인 리더 안테나를 사용하였을 때 자유공간에서는 3.5m, 유리 부착 시 2.61m, 액체가 든 유리병 부착 시 2.51m 의 인식거리 성능을 보였다.

• Tuberculosis and Respiratory Diseases
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• v.43 no.2
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• pp.210-220
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• 1996

Background : Neutrophils or monocytes separated in vitro by the adherence to plastic surface are known to be activated by surface adherence itself and subsequent experimental data might be altered by surface adherence. In the process of surface adherence, adhesion molecules have a clear role in intracellular signal pathway of cellular activation. Human alveolar macrophages(HAM) are frequently purified by the adherence procedure after bronchoalveolar lavage. But the experimental data of many reports about alveolar macrophages have ignored the possibility of adhesion-induced cellular activation. Method : Bronchoalveolar lavage was performed in the person whose lung of either side was confirmed to be normal by chest CT. With the measurement of hydrogen peroxide release from adherent HAM to plastic surface and non-adherent HAM with or without additional stimulation of phorbol myristate acetate(PMA) or N-formyl-methionyl-leucyl-phenylalanine (fMLP), we observed the effect of the adherence to plastic surface. We also evaluated the effect of various biological surfaces on adhesion-induced activation of HAM. Then, to define the intracellular pathway of signal transduction, pretreatment with cycloheximide, pertussis toxin and anti-CD11/CD18 monoclonal antibody was done and we measured hydrogen peroxide in the culture supernatant of HAM. Results : 1) The adherence itself to plastic surface directly stimulated hydrogen peroxide release from human alveolar macrophages and chemical stimuli such as phorbol myristate acetate(PMA) or N-formyl-methionyl-leucyl-phenylalanine(fMLP) colud not increase hydrogen peroxide release in these adherent macrophages which is already activated. 2) PMA activated human alveolar macrophages irrespective of the state of adhesion. However, fMLP stimulated the release of hydrogen peroxide from the adherent macrophages, but not from the non-adherent macrophages. 3) HAM adherent to A549 cell(type II alveolar epithelium-like human cell line) monolayer released more hydrogen peroxide in response to both PMA and fMLP. This adherence-dependent effect of fMLP was blocked by pretreatment of macrophages with cycloheximide, pertussis toxin and anti-CD18 monoclonal antibody, Conclusion : These results suggest that the stimulatory effect of PMA and fMLP can not be found in adherent macrophage because of the activation of human alveolar macrophage by the adherence to plastic surface and the cells adhered to biologic surface such as alveolar epithelial cells are appropriately responsive to these stimuli. It is also likely that the effect of fMLP on the adherent macrophage requires new protein synthesis via G protein pathway and is dependent on the adhesion between alveolar macrophages and alveolar epithelial cells by virtue of CD11/CD18 adhesion molecules.

• Journal of the Korea Concrete Institute
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• v.21 no.3
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• pp.275-282
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• 2009

The effects of surface treatment method of reinforcing fiber on the bonding strength between carbon fiber reinforced polymer rebar (CFRP rebar) and high strength concrete have been evaluated in this study. The structural PVA fiber is coated with a proprietary hydrophobicoiling agent and crimped type polyolefin based structural synthetic fiber is deformed with a geometrical modification were used for the reinforcing fiber. The compressive tests have been performed to evaluate the strength property of high strength concrete depending on the surface treatment method of fiber. The bonding property between the high strength concrete and the CFRP rebar was evaluated by means of direct bonding test. The test results indicated that the surface treatment method of fiber effect on the bonding behavior of high strength concrete and CFRP rebar. Also, as the development and propagation of splitting cracks were controled by adding fibers into the high strength concrete, the bonding behavior, bond strength and relative bonding strength of CFRP rebar and high strength concrete were significantly improved.

• Journal of Biosystems Engineering
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• v.24 no.6
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• pp.479-486
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• 1999

A measurement method for the deposition amount of spray, using tracer and spectrophotometer was developed. Food colors was selected as tracer, because it was cheep and easily treatable. Using NIRS(Near Infrared Reflection Spectrophotometer), regression curves between absorbance spectrum and concentration of the tracer were obtained. Yellow food colors showed the peak of spectrum at 452nm, and absorbance of peak showed a tendency to increase as concentration increased. Also, the possibility of concentration control by heating was investigated.