미세 연소기 개발 (III) - 감광 유리를 이용한 마이크로 엔진의 제작 -

이대훈,박대은,윤준보,윤의식,권세진,Lee, Dae-Hoon,Park, Dae-Eun,Yoon, Joon-Bo,Yoon, Eui-Sik,Kwon, Se-Jin 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.12

Micro engine that includes Micro scale combustor is fabricated. Design target was focused on the observation of combustion driven actuation in MEMS scale. Combustor design parameters are somewhat less than the size recommended by feasibility test. The engine structure is fabricated by isotropic etching of the photosensitive glass wafers. Electrode formed by electroplating of the Nickel. Photosensitive glass can be etched isotropically with almost vertical angle. Bonding and assembly of structured photosensitive glass wafer form the engine. Combustor size was determined to be 1 mm scale. Movable piston is engraved inside the wafer. Ignition was done by nickel spark plug which was electroplated with thickness of 40 ${\mu}{\textrm}{m}$. The wafers were bonded by epoxy that resists high temperature. In firing test due to the bonding method and design tolerance pressure buildup by reaction was not confirmed. But ignition, flame propagation and actuation of micro structure from the reaction was observed. From the result basement of design and fabrication technology was obtained.

형상 축소된 연소기의 열손실 및 소염해석 모델

이대훈,권세진,Lee, Dae-Hoon,Kwon, Se-Jin 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.7

Down scaled combustor undergoes increased heat loss that results in incomplete combustion or quenching of the flame as a consequence. Therefore, effect of enhanced heat loss should be understood to design a MEMS scale combustion devices. Existing combustion models are inadequate for micro combustors because they were developed for analysis of regular scale combustor where heat loss can be ignored during the flame propagation. In this research a combustion model is proposed in order to estimate the heat loss and predict quenching limit of flame in a down scaled combustor. Heat loss in the burned region is expressed in a convective form as a product of wall surface area, heat transfer coefficient and temperature difference. Comparison to the measurements showed satisfactory agreement of the pressure and temperature drop. Quenching is accounted for by introducing a correlation of quenching parameter and heat loss. The present model predicted burnt fraction of gases with reasonable accuracy and proved to be applicable in thermal design of a micro combustor.

PET/PTT/Rayon 스테이플 혼방직물의 역학적 특성

이대훈,최규락,나미희,차희철,Lee, Dae-Hoon,Choi, Kue-Lak,Na, Mi-Hee,Cha, Hee-Chul 한국섬유공학회 2012 한국섬유공학회지 Vol.49 No.2

The mechanical properties and strain at applied loads for PET/PTT (polyester/poly trimethylene terephthalate)/rayon staple blended fabrics, PET/rayon blended fabrics, and PET/rayon containing PU fabrics were studied. The result of the research shows that PET/PTT/rayon staple blended fabrics have higher bending and shear properties than other fabrics in cases regarding the weft direction. Elastic recovery above a 30% strain of PET/PTT/rayon staple blended fabrics is larger than that of other fabrics. PET/PTT/rayon staple blended fabrics are easily extensible at the small as well as the large deformation region.

효소종류에 따른 불등풀가사리 유래 다당류의 이화학적 특성 및 생리활성

이대훈,홍주헌,Lee, Dae-Hoon,Hong, Joo-Heon 한국식품저장유통학회 2017 한국식품저장유통학회지 Vol.24 No.3

본 연구에서는 불등풀가사리 유래 다당류의 기능성식품소재로의 활용성을 향상시키고자 불등풀가사리에 5종의 상업용 효소를 처리한 다음 분리된 다당류의 이화학적 특성 및 생리활성을 조사하였다. 효소 분해 구간의 다당 수율은 52.8-66.4%로 무처리 구간 50.6%에 비해 유의적으로 증가하였다. 이화학적 특성으로 총당 및 단백질 함량은 각각 71.04% 및 7.22%, uronic acid 및 sulfate 함량은 23.18 g/100 g 및 28.27%로 효소 분해를 통해 증가하였다. DPPH radical 소거활성 및 FRAP에 의한 항산화 활성은 23.10% 및 $218.50{\mu}M$을 나타내어 무처리 구간에 비해 항산화 활성이 우수하였으며, L132 세포 사멸에 대한 보호효과는 viscozyme 효소처리 구간($1{\mu}g/mL$)에서 $H_2O_2$를 처리한 구간 대비 세포 보호효과는 85.64%로 세포 활성이 증가하여 높은 세포 보호효과를 나타내었다. NO 생산량은 viscozyme 효소 처리구간 $5{\mu}g/mL$ 농도에서 $32.13{\mu}M$ 함량을 나타내어 LPS 대비 90% 높은 생성량을 나타내었으며, 4종의 암세포(A549, SNU719, HeLa 및 MCF7) 생존율은 $25{\mu}g/mL$농도에서 각각 69.57%, 61.06%, 52.74% 및 68.64%의 유의적으로 낮은 암세포 생존율을 나타내었다. 따라서 불등풀가사리의 효소 분해를 통해 다당의 이화학적 특성 및 생리활성이 향상됨에 따라 기능성 식품소재 로 다양하게 활용 가능할 것으로 사료된다. In this study, the biological activities and physicochemical properties of polysaccharides from Gloiopeltis furcata were investigated. Polysaccharides were isolated by enzymes treatment (celluclast, flavourzyme, papain, termamyl, viscozyme) followed by ethanol precipitation and lyophilization. The yield of polysaccharides by enzymes treatment group were 52.8-66.4%. The major constituents in viscozyme treatment group were total sugar (71.04%), protein (7.22%), uronic acid (23.18 g/100 g), and sulfate (28.27%), respectively. The DPPH radical scavenging activity and ferric reducing antioxidant potential of the viscozyme treatment group at 5 mg/mL were 23.10% and $218.50{\mu}M$, respectively. The protective effects against $H_2O_2$-induced cytotoxicity in L132 cell of viscozyme treatment group at $1{\mu}g/mL$ was 85.64%. The viscozyme treatment group increased the production of nitric oxide (NO) in a dose-dependent manner. The antitumor activity of viscozyme treatment group (at $25{\mu}g/mL$) in A549, HeLa, SNU719 and MCF7 was 69.57%, 52.74%, 61.06% and 68.64%, respectively. All of data showed that the biological activities and chemical characteristics of enzymes treatment group are higher than that of the control group. The polysaccharides isolated from Gloiopeltis furcata investigated herein are useful as functional materials agents.

불등풀가사리 다당류의 분자량에 따른 이화학적 품질특성 및 피부 주름 개선 효과

이대훈,홍주헌,Lee, Dae-Hoon,Hong, Joo-Heon 한국식품저장유통학회 2017 한국식품저장유통학회지 Vol.24 No.5

본 연구는 불등풀가사리로부터 분리된 조다당류와 산가수분해된 다당류의 분자량에 따른 이화학적 품질특성과 항산화 활성 및 피부 주름 개선 효과를 확인하였다. 산가수분해 분자량별 다당류의 수율은 100 kDa 이상에서 29.6%로 가장 높았으며, 10 kDa 이하에서 10.4%로 가장 낮았다. 이화학적 특성으로 총당, uronic acid, sulfate 함량은 100 kDa 이상에서 각각 85.82%, 32.85 g/100g 및 39.04%로 조다당에 비해 증가하였다. 색도은 분자량이 증가함에 따라 L 값, a 값 및 b 값이 감소하였으며, 점도는 분자량이 높을수록 증가하였다. ORAC 활성은 100 kDa 이상에서 $180.07{\mu}M$을 나타내어 조다당 $34.70{\mu}M$에 비해 항산화활성이 우수하였다. L132 세포 사멸에 대한 보호효과는 $H_2O_2$ 처리 구간대비 분자량 100 kDa 이상($0.5-5{\mu}g/mL$)에서 87.34-103.85%로 세포 활성이 증가하여 세포 보호효과를 나타내었다. MMP-1 활성은 세포에 UVB를 조사한 후 분자량 100 kDa 이상 $0.05-0.5{\mu}g/mL$ 농도에서 69.67-100.87%의 저해 활성을 나타내었다. 또한, pro-collagen 생합성 역시 UVB를 조사한 후 분자량 100 kDa 이상 $0.05-0.5{\mu}g/mL$ 농도에서 64.91-77.80%의 합성능을 나타내어 농도 의존적으로 증가하는 것을 확인하였다. 따라서, 불등풀가사리 유래 산가수분해된 다당류의 분자량에 따른 주름 개선 효과를 통해 피부 항노화 기능성 소재로 다양하게 활용 가능할 것으로 사료된다. In this study, the physicochemical properties and anti-wrinkle effect of polysaccharides with different molecular weights from Gloiopeltis furcata were investigated. Crude polysaccharides were isolated by viscozyme treatment followed by ethanol precipitation and lyophilization. Crude polysaccharides were hydrolyzed by acid (0.1 N HCl) and the molecular weight fractions were generated by centrifugal filter (<10 kDa, 10 to 100 kDa, and 100 kDa>). The yield of polysaccharides with different molecular weight fractions was 8.4-39.6%. The major constituents in molecular weight fractions were total sugar (81.37-85.82%), uronic acid (27.89-32.85 g/100 g), sulfate (33.38-39.04%), and protein (0.35-3.16%) The L, a, and b value of the 100 kDa group were decreased, but viscosity increased. The oxygen radical absorbance capacity of the 100 kDa group at $180.07{\mu}M$ was the highest among groups. The protective effects of 100 kDa group at 0.5 and $5{\mu}g/mL$ against $H_2O_2$-induced cytotoxicity in L132 cell were 87.34% and 103.85%, respectively. The matrix metalloproteinase-1 activity of 100 kDa group decreased in a dose-dependent manner. The pro-collagen synthesis activity of 100 kDa group at $0.05-0.5{\mu}g/mL$ was 64.91-77.80%. The polysaccharides with different molecular weights from Gloiopeltis furcata investigated herein are useful as a potential candidate for cosmedical materials.

Li-ion 전지 성능 개선을 위한 플라즈마 기술 응용

이대훈,허민,Lee, Dae-Hun,Heo, Min 재료연구소 2010 機械와 材料 Vol.22 No.3

최근 아이폰, 아이패드 등으로 대표되는 소형 가전의 보급이 확대되고 있으며 hybrid 및 plug-in 전기자동차가 주목을 받으면서 2차 전지 기술에 대한 시장과 기술의 관심이 높아지고 있다. 2차 전지 기술은 기본적으로 전기 화학과 재료 분야 연구자들의 역할이 중요하지만 생산 및 공정이라는 관점에서 기계공학 연구자들이 기여할 부분들이 많이 있다. 본 논고에서는 특히 플라즈마 기술을 이용, 2차 전지의 성능 개선 및 혁신을 위한 기술적 접근 가능성에 대해 살펴보고 몇 가지 가능한 연구 주제들을 제시하고자 한다.

난류 예혼합 화염에서의 프랙탈 차원의 통계적 특성

이대훈,권세진,Lee, Dae-Hun,Gwon, Se-Jin 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.1

With the introduction of Fractal notation, various fields of engineering adopted fractal notation to express characteristics of geometry involved and one of the most frequently applied areas was turbulence. With research on turbulence regarding the surface as fractal geometry, attempts to analyze turbulent premised flame as fractal geometry also attracted attention as a tool for modeling, for the flame surface can be viewed as fractal geometry. Experiments focused on disclosure of flame characteristics by measuring fractal parameters were done by researchers. But robust principle or theory can't be extracted. Only reported modeling efforts using fractal dimension is flame speed model by Gouldin. This model gives good predictions of flame speed in unstrained case but not in highly strained flame condition. In this research, approaches regarding fractal dimension of flame as one representative value is pointed out as a reason for the absence of robust model. And as an extort to establish robust modeling, Presents methods treating fractal dimension as statistical variable. From this approach flame characteristics reported by experiments such as Da effect on flame structure can be seen quantitatively and shows possibility of flame modeling using fractal parameters with statistical method. From this result more quantitative model can be derived.

에어젯 정방사의 기하학적 구조와 역학적 성질간의 관계

이대훈,김의화,이승미,Lee, Dae-Hun,Kim, Ui-Hwa,Lee, Seung-Mi 한국섬유공학회 1989 한국섬유공학회지 Vol.26 No.5

The microscopic structure of the yarn was observed in order to clarify the reason why the mechanical properties of the air-jet spun yarns differ from those of the ring or opened rotor yarns. Some structural parameters of the yarns were obtained by the tracer fibre technique. Zonal distributions of the constituent fibres were derived and the orientation density functions of the fibres in the several yarns were introduced by the statistical method. The distributions of the polar angle in all yarns have a good correlation with the radial direction of yarns, but those of azimuthal angles were random. It was observed microscopically that the air-jet spun yarns were constituted of the false twisted fibres, fasciated fibres, wrapping fibres and fuzz although their fractions will be changed by the spinning parameters. The most of the fibres in air-jet spun yarns are oriented to the yarn axis. Therefore the constituent fibres contact each other more closely, so that the yarn bulkiness decreases. The relative initial modulus of air-jet spun yarns is lower than that of ring or open-end rotor yarns and it is ascribed to the distribution of polar angles of the fasciated fibres in the air-jet spun yarns.

에어젯 정방사의 구조와 역학적 성질

이대훈,전붕수,김승진,Lee, Dae-Hun,Jeon, Bung-Su,Kim, Seung-Jin 한국섬유공학회 1990 한국섬유공학회지 Vol.27 No.8

미세 연소기 개발(I) - 소형 연소기 환경에서의 연소 특성 -

이대훈,최권형,권세진,Lee, Dae-Hun,Choe, Gwon-Hyeong,Gwon, Se-Jin 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.1

Combustion phenomena in a sub-millimeter scale combustor have been investigated. To evaluate scale effect on flame propagation characteristics, a cylindrical combustion chamber with variable depth was built in-house. The combustor was charged with premixed gas of hydrogen and air and ignited electronically. A piezo electric pressure transducer recorded transient pressure after the ignition. Measurements were made at different test conditions specified with chamber depth and initial pressure as parameters. Visual observation was made through a quartz glass window on top side of the combustion chamber using high speed digital video camera. From the pressure data, available work was estimated and compared with energy input required for stable ignition. The preliminary results suggested that the net thermal energy release is sufficient to generate power and enables a combustor of the size in the present study to be used as the energy source of a micro power devices .