• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.350-356
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• 1988

A pilot plant scale freeze dryer was designed and manufactured and its performance was tested. Freezing capacity of water vapor in the developed freeze dryer was 8㎏/batch and heating and defrosting methods were conduction and hot gas types, respectively. And exhausting time of vacuum pump was 7-8 minutes and temperature of cold trap was kept below $-50^{\circ}C$. In the freeze drying of fruits and vegetables, its optimum and maximum drying capacities were 2 and 4㎏/batch, respectively. Performance of the new freeze dryer was compared quite well with a foreign made freeze dryer.

• Korean Chemical Engineering Research
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• v.45 no.2
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• pp.149-154
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• 2007

Nanoimprint lithography (NIL) is useful technique because of its low cost and high throughput capability for the fabrication of sub-micrometer patterns which has potential applications in micro-optics, magnetic memory devices, bio sensors, and photonic crystals. Usually, a chemical surface treatment of the stamp is needed to ensure a clean release after imprinting and to protect the expensive original master against contamination. Meanwhile, adhesion promoter between resin and substrate is also important in the nanoscale pattern. In this work, we have investigated the effect of surface treatment using silane coupling agent as release layer and adhesion promoter for UV-Nanoimprint lithography. Uniform SAM (self-assembled monolayer) could be fabricated by vapor deposition method. Vapor phase process eliminates the use of organic solvents and greatly simplifies the handling of the sample. It was also proven that 3-acryloxypropyl methyl dichlorosilane (APMDS) could strongly improve the adhesion force between resin and substrate compared with common planarization layer such as DUV-30J or oxygen plasma treatment.

• Journal of Integrative Natural Science
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• v.5 no.4
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• pp.237-240
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• 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.

• Journal of the Korean Institute of Gas
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• v.17 no.6
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• pp.1-7
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• 2013

Internal pressure variation analysis and actual holding time test on ISO LNG tank containers which were made in Korea for the first time according to the special notification of ISO tank container manufacture have been conducted during the transport demonstration projects of the tank containers by tractor, train and ship. The internal pressure of the LNG tank container increased rapidly after LNG filling and dropped during moving the container. However, it was stabilized as time passed and followed the liquid-vapor equilibrium graph. In addition, actual holding time of the tank container was more than 20 days which was satisfied with the special notification of LNG tank container manufacture.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.41-43
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• 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
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• v.32 no.3
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• pp.461-467
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• 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.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.3
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• pp.209-216
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• 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.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.3
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• pp.294-302
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• 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
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• v.9 no.1_2
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• pp.22-25
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• 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.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.4
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• pp.124-131
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• 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.