• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.875-876
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• 2010

• Journal of Mechanical Science and Technology
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• v.14 no.9
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• pp.928-934
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• 2000

This paper describes a method developed for the simulation of ring pack lubrication characteristic in an internal combustion engine. In general, the quantity of oil supply for piston ring lubrication may be insufficient in filling the entire volume formed at the interference between the piston ring and the cylinder liner. Thus the oil starvation condition should be considered in analyzing piston ring lubrication. In order to reasonably estimate the amount of oil left over on the cylinder liner, the flow rate at the posterior portion of the interface should be calculated with an adequate boundary condition that confirms flow continuity condition. In this analysis, oil starvation and open-end boundary conditions are considered at the inlet and outlet of the piston rings. The lubrication characteristic of each piston ring is obtained by an iterative method with sequential steps. It is revealed that piston rings are operated under oil starvation in most operating cycles and the result under these conditions are quite different from that with the fully-flooded assumption.

• Food Science and Preservation
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• v.24 no.7
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• pp.898-907
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• 2017

This study was aimed to test harvest time effect with polyethylene (PE) film liner, 1-methylcyclopropene (1-MCP) and aminoethoxyvinylglycine (AVG) treatments on fruit quality attributes in 'Sangjudungsi' persimmon fruit during cold storage. The fruits were harvested 10 days earlier in 2016 than the mature harvest time in 2015. The ethylene production was significantly lower in early harvested fruits than in mature harvested ones. Flesh firmness was maintained higher in 1-MCP treated fruit than in other treatments during cold storage. The rate of fruit weight loss was significantly inhibited by PE film liner treatment during storage, regardless of harvest time. 1-MCP treatment showed less change in fruit peel color variables ($L^*$ and $b^*$) from the calyx-end and equatorial regions during cold storage, compared with those from the control and PE film treatments. The incidence rate of fruit decay and softening was higher in PE film treated fruits than in the other treatments. However, there was no decay detected in AVG treated fruit. The early harvested fruits were maintained higher flesh firmness, compared with mature harvested fruits. Nevertheless, the mature harvested fruits showed much higher soluble solids content, the redness (Hunter a value) of the fruit peel and respiration rate, compared with early harvested fruits. Furthermore, the rate of weight loss in the fruit was remarkably inhibited in the PE film treatment.

• Journal of Surface Science and Engineering
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• v.23 no.1
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• pp.34-43
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• 1990

Al-Si piston alloys such as AlS10CuMg have been anodized to examine apossibility of forming a hard film aat relatively higher temperatures compard with those in conventional sulfuric acid processes. Three types of electrolytes have been employed in this study ; electrolyte A(15% H2SO4, $0^{\circ}C$), electrolyte B(12% H2SO4, 1% oxalic, $10^{\circ}C$), electrolyte C(tartaric acid 125g/L+oxalic 75g/L+aluminum sulfate 225g/L, $25^{\circ}C$). Hard anodisine process in electrolyte B at a current density of 1.54A/dm2 produced a harder film of VHN 396 at a relatibely low film forming voltage compared with those obtained in other electrolyte at equivalent current density. A liner relationship between hardness and abrasion resistance exists for Al-Si piston alloys. The hardness of anodized film decreasees with increasing silicon content in Al-Si alloys and also with bath temperature. The film hardeness of Na-modified alloy os higher than that of P-modified alloy due to its finer microstructre. The film on the silicon phase in Al-Si alloys is observed to be formed by lateral growth of oxide film nucleated at surroundings.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.6
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• pp.870-879
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• 2000

An experimental investigation is conducted to improve a slot film cooling system which can be used for the cooling of gas turbine combustor liner. The tangential slots are constructed of discrete holes with different injection types which are the parallel, vertical, and combined to the slot lip. The investigation is focused on the coolant supply systems of normal-, parallel-, and counter-flow paths to the mainstream direction. A naphthalene sublimation technique has been employed to measure the local heat/mass transfer coefficients in a slot with various injection types and coolant feeding directions. The velocity distributions at the exit of slot lip for the parallel and vertical injection types are fairly uniform with mild periodical patterns with respect to the hole positions. However, the combined injection type increases the nonuniformity of flow distribution with the period equaling twice that of hole-to-hole pitch due to splitting and merging of the ejected flows. The secondary flow at the lip exit has uniform velocity distributions for the parallel and vertical injection types, which are similar to the results of a two-dimensional slot injection. In the results of local heat/mass transfer coefficient, the best cooling performance inside the slot is obtained with the vertical injection type among the three different injection types due to the effect of jet impingement. The lateral distributions of Sh with the parallel- and counter-flow paths are more uniform than the normal flow path. The averaged Sh with the injection holes are $2{\sim}5$ times higher than that of a smooth two-dimensional slot path.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.9
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• pp.1251-1255
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• 2006

To improve the water resistance and physical properties of soy protein isolate (SPI)-coated paper, effects of concentrations of soy protein isolate and plasticizer were examined. Physical properties such as elongation strength (ES), elongation rate (E), water vapor permeability (WVP), and water solubility (WS) were evaluated. The film made from 5% soy protein isolate (SPI) and 40% glycerol (plasticizer) suggested a good application for a film preparation. SPI coated paper showed the highest ES (21.62 MPa) and the lowest WVP $(2.06ng{\cdot}m/m^2{\cdot}s{\cdot}Pa)$ and WS (1.17%). This study suggested that soy protein isolate (SPI) can be used as a coating material for the coated paper to improve the water resistance.

• Journal of the Korean Graphic Arts Communication Society
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• v.20 no.1
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• pp.91-101
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• 2002

An acid amplifier is defined as an acid-generating agent which is decomposed autocatalytically to produce new strongly acidic molecules in a non-liner manner, The addition of the acid amplifiers to conventional chemically amplified photoresists consisting of photoacid generators and acid-sensitive polymers result in the improvement of photosensitivity due to the amplified generation of catalytic acid molecules as a result of the decomposition of acid amplifiers. We synthesized and evaluated 1-hydroxy-4-tosyloxy cyclohexane(AA-1) and 1,4-ditosyloxy cyclohexane(Ah-2) as novel acid amplifiers. The acid amplifiers(AA-1, AA-2) showed reasonable thermal stability for resist processing temperature. As estimated by the sensitivity curve, tort-butyl methacrylate homopolymer(ptBMA) film doped with AA-1 or 2 exhibited much higher photosensitivity than ptBMA film without AA-1 or 2. And AA-1 showed higher effect than AA-2 on enhancing photosensitivity of ptBMA film.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.299-302
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• 2000

RTD temperature sensor is a thermoresistor which uses the liner dependence of the resistance of the sensing material on the temperature, and has good stability and sensibility, so it can be used in highly precise temperature measurement. In this study RTD sensor was fabricated using Pt thin film. The Pt thin film was deposited on alumina using DC-Sputter, and annealed with various temperature. Through the experiments of XRD, AFM, 4-point probe, the surface structure of the thin film with annealing conditions and their effects on the electrical resistance were investigated. RTD with serpentine pattern was fabricated using Lift-off and resistance-temperature characteristics were studied.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05b
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• pp.38-41
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• 2001

In this work, we have been studied the characteristics of each nitride film for the optimization of PMD(pre-metal dielectric) liner nitride process, which can applicable in the recent semiconductor manufacturing process. The deposition conditions of nitride film were splited by PO (protect overcoat) nitride, baseline, low hydrogen, high stress and low hydrogen, respectively. And also we tried to catch hold of correlation between BPSG(boro-phospho silicate glass) deposition and densification. Especially, we used FTIR area method for the analysis of density change of Si-H bonding and Si-NH-Si bonding, which decides the characteristics of nitride film. To judge whether the deposited films were safe or not, we investigated the crack generation of wafer edge after BPSG densification, and the changes of nitride film stress as a function of RF power variation.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.5
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• pp.105-113
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• 2000

In order to clarify the final process of oil consumption, the distribution and flow of oil through each ring were visualized by induced fluorescence method. Motoring and firing test were performed in a single cylinder research engine with transparent cylinder liner. The appropriate calibration techniques were used to solve the unstability of induced light intensity as well as to know the relation of the oil film thickness and output signal. Oil behavior was also observed at dynamic state by high speed CCD camera. By analyzing the oil film thickness converted from the photographed image, it was observed that the main route of oil transport through each ring is the end gap under the usual operating condition, low engine speed and low load condition. Oil film thickness is observed to be irregular and tend to move in a body horizontally at a given piston land. And it is also found that oil flows through oil ring gap so quickly that it can be observed in a single cycle, but it flows so slowly through top and 2nd compression rings that it takes quite a long time to detect the flow.