• 한국식품과학회지
• /
• 제20권3호
• /
• pp.350-356
• /
• 1988

식품 산업에서 이용도가 높을 뿐 아니라 외국 의존도가 높은 진공동결건조기를 reverse enginerring 하여 국산화 개발한 후 그 성능을 시험하였다. 새로 개발한 진공동결건조기는 1 batch 당 8kg의 수증기를 응결시킬 수 있으며, 전도가열에 의해 열판 온도를 $80^{\circ}C$까지 올릴 수 있고 제상방법은 hot gas 방식을 취했다. 진공펌프의 배기시간은 $7{\sim}8$분, cold trap의 온도는 $-50^{\circ}C$까지 유지할 수 있었으며, 잔공동결건조기의 최적 건조능력은 과채류의 경우 batch 당 2kg 정도이며 최고 4kg 까지 건조시킬 수 있었다. 개발한 진공동결건 조기와 기존의 외국산 진공동결건조기를 이용$(^{5,6})$하여 당근을 동결건조시킨 경우 양 장치간에 별 차이는 없었으며, 각 식품의 진공동결건조 특성은 각 식품의 초기 수분 함량 및 초기성상에 영향을 받는 것으로 나타났다.

• Korean Chemical Engineering Research
• /
• 제45권2호
• /
• pp.149-154
• /
• 2007

나노임프린트 공정기술은 나노구조물이 패턴된 스템프(혹은 몰드)를 이용하여 적절한 기판 위에 나노구조물을 복제하여 패턴을 전사하는 기술이다. 효과적인 나노임프린트 공정을 위해서는 몰드의 이형처리뿐 아니라 반대쪽의 기질과 레지스트 사이에 접착력 증가(adhesion promoter) 처리가 매우 중요한 역할을 한다. 본 연구에서는 자기조립 실란커플링제의 기상증착을 이용하여 나노임프린트 공정에서 사용되는 접착 증가막 및 표면처리 방법을 비교 분석 하였다. 이를 위해서 평탄화층(DUV-30J), 산소 플라즈마 처리, 실란커플링제 자기조립막이 비교되었다. 실란커플링제 자기조립막이 형성된 실리콘 표면은 전체적으로 나노 두께의 균일한 막이 형성되며 임프린트시 구조물들을 정밀하게 전사하였으며 3-acryloxypropyl methyl dichlorosilane(APMDS)을 이용한 자기조립막(SAMs) 처리가 평탄화층과 산소 플라즈마 처리보다 강한 접착력을 가지고 있어 나노임프린트 공정에 적합함을 알 수 있었다.

• 통합자연과학논문집
• /
• 제5권4호
• /
• pp.237-240
• /
• 2012

In this study, PEDOT thin films polymerized with Iron(III)tosylate ($Fe(PTS)_3$) and grown on atomically smooth and highly dense 3-aminopropyltriethoxysilane self-assembled monolayer (APS-SAM) surfaces by VPP method have been investigated. PEDOT thin films were synthesized on APS self-assembled $SiO_2$ wafer surface at two different concentrations (20 wt% and 40 wt%) and growth time (3 and 30 minutes), and then their sheet resistance were measured and compared. PEDOT thin films grown with 20 wt% $Fe(PTS)_3$ oxidant are highly conductive when compared with the film grown with 40 wt% $Fe(PTS)_3$, as ascertained by the measured sheet resistance values down to 0.06 ${\Omega}/cm$. It clearly suggests that 20 wt% is more effective oxidant concentration for VPP than 40 wt% even though the film grown with 40 wt% oxidant has better quality than the film with 20 wt% $Fe(PTS)_3$ does.

• 한국가스학회지
• /
• 제17권6호
• /
• pp.1-7
• /
• 2013

이 논문에서는 특례기준에 따라 국내에서 최초로 제작하고 검사한 LNG 탱크 컨테이너를 이용하여 육상 및 해상 운송 시연사업을 하고, 탱크 컨테이너를 운송할 때 탱크 컨테이너 내부에 충전된 LNG의 압력변화와 탱크 컨테이너의 실제 압력유지기간을 측정하였다. 탱크 컨테이너 내부의 압력은 충전 직후에는 급속하게 상승하고, 탱크 컨테이너를 이동할 때 급속히 하강하나, 일정시간이 경과한 후에는 기액평형상태 그래프의 온도-압력 변화와 일치함을 확인하였다. 또한, 탱크 컨테이너의 실제 압력유지기간은 특례기준에서 규정한 20일 이상을 만족함을 확인하였다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
• /
• pp.41-43
• /
• 2004

Plasma polymerized para-xylene ($PP_PX$) deposited by plasma-enhanced chemical vapor deposition (PECVD) was used as the barrier layer on the polyethylene terephthalate (PET) substrate to improve lifetime of the flexible organic light-emitting diodes (FOLEDs). The $PP_PX$ barrier layer deposited on top of the PET substrate with plasma power of 30 W at deposition pressure of 0.2 torr showed transmittance spectra good enough to be applied in FOLED on PET substrates. FOLEDs with the $PP_PX$ barrier layer (barrier-FOLEDs) showed similar I-V and B-V characteristics to FOLEDs without the $PP_PX$ layer (control-FOLEDs). The lifetime of barrier-FOLED was two times longer than that of the control-FOLED. With $PP_PX$ passivation layers, lifetimes of both control and barrier-FOLEDs were improved by more than 4 times. These results show that PECVD deposited $PP_PX$ layers can be used as barrier layers for FOLEDs on plastic substrates as well as passivation layers for general OLEDs.

• Journal of Advanced Marine Engineering and Technology
• /
• 제32권3호
• /
• pp.461-467
• /
• 2008

It was studied the effect of a pre-deposited ultrathin Al layer as part of a buffer layer for the growth of GaN. AlN buffer layers were deposited on a Si(111) substrate using an RF sputtering technique, followed by GaN using hydride vapor phase epitaxy (HVPE). Several atomic layers of Al were deposited prior to AlN sputtering and the samples were compared with the others grown without pre-deposition of Al. And it was also studied the influence of AlN buffer layer thickness on the growth of GaN. The peak wavelength of the photoluminescence (PL) was varied with increasing the thickness of the GaN and AlN layers. The optimum thickness of AlN on a Si(111) substrate with an ultrathin Al layer was about $260{\AA}$. Scanning electron microscope (SEM) images showed coalescent surface morphology and X-ray diffraction (XRD) showed a strongly oriented GaN(0002) peak.

• 대한기계학회논문집A
• /
• 제32권3호
• /
• pp.209-216
• /
• 2008

The application of focused ion beam (FIB) depends on the optimal interaction of the operation parameters between operating parameters which control beam and samples on the stage during the FIB deposition process. This deposition process was investigated systematically in C precursor gas. Under the fine beam conditions (30kV, 40nm beam size, etc), the effect of considered process parameters - dwell time, beam overlap, incident beam angle to tilted surface, minimum frame time and pattern size were investigated from deposition results by the design of experiment. For the process analysis, influence of the parameters on FIB-CVD process was examined with respect to dimensions and constructed shapes of single and multi- patterns. Throughout the single patterning process, optimal conditions were selected. Multi-patterning deposition were presented to show the effect of on-stage parameters. The analysis have provided the sequent beam scan method and the aspect-ratio had the most significant influence for the multi-patterning deposition in the FIB processing. The bitmapped scan method was more efficient than the one-by-one scan type method for obtaining high aspect-ratio (Width/Height > 1) patterns.

• 대한기계학회논문집B
• /
• 제22권3호
• /
• pp.294-302
• /
• 1998

Ignition characteristics of a vertical solid fuel plate with block have been investigated experimentally. For low radiant heat flux, ignition does not occur in a vertical solid fuel plate without block. In the case with the block on a vertical fuel plate, however, ignition can occur by increasing the residence time and the time to absorb the incident radiation flux by fuel vapor in gas phase. The ignition occurs below block and the point varies according to the block location and the block height. As the block height increases, the block locates at higher position, and the hot wall temperature increases, the ignition delay time decreases. Also as the initial temperature of fuel plate rises, the ignition delay time of the solid fuel plate decreases. The temperature distribution of solid fuel plate with block is nearly proportional to the radiant heat flux distribution. Therefore, the effect temperature by natural convection heat transfer is of the same order as that of inhibition of temperature increase by pyrolysis.

• KSTLE International Journal
• /
• 제9권1_2호
• /
• pp.22-25
• /
• 2008

This paper investigated the wetting and adhesion property of undulated DLC film with surface morphology controlled for a reduced real area of contact. The undulated DLC Films were prepared by 13.56 MHZ radio frequency plasma enhanced chemical vapor deposition (r.f. PECVD) by using nanoscale Cu dots surface on a Si (100) substrate. FE-SEM, AFM analysis showed that the after repeated deposition and plasma induced damage with Ar ions, the surface was nanoscale undulated. This phenomenon changed the surface morphology of DLC surface. Raman spectra of film with changed morphology revealed that the plasma induced damage with Ar ions significantly suppressed the graphitization of DLC structure. Also, it was observed that while the untreated flat DLC surfaces had wetting angle starting ranged from $72^{\circ}$ and adhesion force of 333ni. Had wetting angle the undulated DLC surfaces, which resemble the surface morphology of a cylindrical shape, increased up to $104^{\circ}$ and adhesion force decreased down to 11 nN. The measurements agree with Hertz and JKR models. The surface undulation was affected mainly by several factors: the surface morphology affinity to cylindrical shape, reduction of the real area of contact and air pockets trapped in cylindrical asperities of the surface.

• 한국자동차공학회논문집
• /
• 제15권4호
• /
• pp.124-131
• /
• 2007

The numerical study on behavior of impinging spray from high-pressure swirl injector under various ambient temperatures was performed by using spray vaporization model and spray-wall impingement model implemented in modified KIVA code, and these spray models were estimated by comparison with experimental results. To compute the spray-wall impingement process, the Gosman model, which is based on the droplet behavior after impingement determined by experimental correlations, was used. The modified Abramzon and Sirignano model, that includes the effects of variable thermodynamic properties and non-unitary Lewis number in the gas film, was adapted for spray vaporization process. The exciplex fluorescence measurements were also conducted for comparison. The experimental and numerical analysis were carried out at the ambient pressures of 0.1 MPa and at the ambient temperature of 293 K and 473 K, and the spray characteristics, such as spray-wall impingement process, gas velocity field, SMD and vapor concentration, were acquired. It was found that the impinging spray develops active and SMD is small at vaporization conditions.