• Korean Journal of Agricultural Science
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• v.29 no.1
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• pp.15-23
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• 2002

The percentage of watercore occurrence harvested on Nov. 6 (commercial harvest season) was over 80% but fruits seemed not to reach climacteric stage on the basis of ethylene evolution. The occurrence ratio and severity of watercore gradually decreased with the increase of preshipment storage for 2 months. The level of soluble solids did not show a clear tendency during preshipment storage but flesh firmness, fresh weight, and acidity gradually decreased. Although the overall quality of fruit reduced along with the increase of preshipment storage duration after exposure to retail condition at ambient temperature for 1 week, plastic film wrapping (PE 30 um) as well as plastic film wrapping plus ethylene scrubbing had a benefit on keeping freshness of fruit even after retail condition. Waxed fruit showed excellent appearance but browning disorder was developed. Results indicated that moisture barrier such as plastic film wrapping and ethylene removal have a great potential on keeping freshness of fruit during export which required long-term transport under low humidity environment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1882-1888
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• 2008

Effects of 1-MCP(1-methylcyclopropene) on the postharvest life and fruit quality of cucumber 'Baekdadaki' were investigated. Cucumber were held at room and cold chamber($10^{\circ}C$) treated with several concentrations of 1-MCP. Physico-chemical characteristics such as fresh weight and firmness were greatly varied during storage, and the treatment with I-MCP(500ppb) showed the minimal loss of the values at harvest. The peel b value representing a senescence process was higher investigated in 1-MCP(250 and 1,000ppb treatment, and led to the apparent yellowing and softening after cold storage for 15 days. 1-MCP(500ppb) showed lower decay rate and better marketability of cucumber than other treatments after cold storage for 15 days. The respiration rate was higher found in cucumber treated with 1-MCP(250ppb) than in other treatment. Ethylene evolution was most detected in cucumber treated with 1-MCP(1000ppb) after room storage for 6 days. 1-MCP did not affect the production of ethylene in cucumber during room and cold storage.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.367-370
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• 2006

This paper deals with the modeling and simulation of the internal flowfield in a valveless airbreathing pulse detonation engine (PDE) currently under experimental development at the U.S. Naval Postgraduate School. The system involves no valves in the airflow path, and the isolation between the inlet and combustor is achieved through the gasdynamics in an isolator. The analysis accommodates the full conservation equations in axisymmetric coordinates, and takes into account variable properties for ethylene/oxygen/air system. Chemical reaction schemes with a single progress variable are implemented to minimize the computational burden. Detailed flow evolution during a full cycle is explored and propulsive performance is calculated. Effect of initiator mass injection rate is examined and results indicate that the mass injection rate should be carefully selected to avoid the formation of recirculation zones in the initial cold flowfield. Flow evolution results demonstrate a successful detonation transmission from the initiator to the combustor. However, strong pressure disturbance may propagate upstream to the inlet nozzle, suggesting the current configuration could be further refined to provide more efficient isolation between the inlet and combustor.

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.145-148
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• 2011

The thermal behavior of lithiated Si anodes has been investigated using differential scanning calorimetry (DSC). In particular, the effect of Si particle size on the thermal stability of a fully lithiated Si electrode was investigated. For DSC measurements, a lithiated Si anode was heated in a hermetically sealed high-pressure pan with a polyvinylidene fluoride (PVDF) binder and a 1 M $LiPF_6$ solution in an ethylene carbonate (EC)-diethyl carbonate (DEC) mixture. The thermal evolution around $140^{\circ}C$ increases with lithiation and with decreasing particle size; this phenomenon is attributed to the thermal decomposition of the solid electrolyte interface (SEI) film. Exothermic peaks, following a broad peak at around $140^{\circ}C$, shift to a lower temperature with a decrease in particle size, indicating that the thermal stability of the lithiated Si electrode strongly depends on the Si particle size.

• Macromolecular Research
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• v.17 no.11
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• pp.879-885
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• 2009

A macroazoinitiator (MAI) containing a poly(ethylene glycol) (PEG) segment was intercalated in the gallery of sodium montmorillonite (Na-MMT). Acrylic monomers were polymerized using this MAI intercalated in Na-MMT to prepare the acrylic copolymer nanocomposite (AN), which is a multiblock copolymer composed of two segments, an acrylic copolymer and PEG intercalated in Na-MMT (Na-MMT/PEG). When AN was used to modify the reactive hot melt polyurethane adhesive (RHA), the acrylic copolymer segment and Na-MMT/PEG synergistically enhanced the initial bond strength evolution and reduced the set time, even when the amount of Na-MMT in RHA was < 1 wt%. The viscosity of RHA increased and the tensile properties of the cured RHA film decreased due to modification with AN. These variations were more evident as the Na-MMT content in AN was increased.

• Food Science and Preservation
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• v.6 no.2
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• pp.153-160
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• 1999

This study was carried out to investigate the production of C$_2$H$_4$ and CO$_2$, and the change of flesh firmness and peel color in 'Fuji' apples during CA storage. ACC oxidase activity was more inhibited by the low O$_2$ concentration, and the low level of internal C$_2$H$_4$ in apples was maintained under the low O$_2$ conditions during 8 months storage. Especially, the level of internal C$_2$H$_4$ in apples was maintained below 1 ppm during storage under 1% O$_2$+1% CO$_2$ at 0$^{\circ}C$, and not much changed for 7 days in air at 20$^{\circ}C$ after storage. The influence of CO$_2$ on the C$_2$H$_4$ production was dependent on the O$_2$ concentration. Increasing of CO$_2$ concentration with 3% O$_2$ decreased the C$_2$H$_4$ Production during storage, but that with 1% O$_2$increased. Internal C$_2$H$_4$ concentration and the rate of CO$_2$ evolution in apples showed the close correlation. Internal CO$_2$ concentration of apples was positively related to the rate of CO$_2$ evolution and maintained the lower level in 1% O$_2$+1% CO$_2$ than the other conditions during storage but nu different in the increment after storage. The relationship between C$_2$H$_4$ and CO$_2$ production was exhibited in CA and the short-term air stored apples, but not in the long-term air stored apples. Loss of flesh firmness and green color in apples was more less in storage condition retarded effectively the production of C$_2$H$_4$ and CO$_2$.

• Horticultural Science & Technology
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• v.29 no.3
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• pp.224-231
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• 2011

Effects of 1-methylcyclopropene (1-MCP) treatment and controlled atmosphere (CA) storage was analyzed for the export quality of 'Fuji' apples after 8-month storage. Apples were harvested from two orchards located in different regions at relatively late stage of maturity for long-term storage. Fruit were treated with 1 ${\mu}L{\cdot}L^{-1}$ 1-MCP and then stored in $0^{\circ}C$ air or CA with 1.5 kPa $O_2$ and < 1.0 kPa $CO_2$ for 8 months. To simulate poststorage export process such as 2-week refrigerated container shipment plus 7-day local distribution, fruit were put in $0^{\circ}C$ air storage for additional two weeks and then on the shelf for 7 days at $20^{\circ}C$. Both the 1-MCP treatment and CA storage reduced respiration and ethylene evolution after storage and shipping simulation, and successfully maintained titratable acidity and flesh firmness even after the export process. In 'Fuji' apples harvested after adequate stage of maturity for long-term storage, however, 1-MCP treatment alone seemed not to be satisfactory for the maintenance of sensorial fruit texture for export market. CA storage or 1-MCP treatment/CA storage combination program should be applied for lately harvested 'Fuji' apples exported after eight months storage.

• Horticultural Science & Technology
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• v.30 no.4
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• pp.400-408
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• 2012

Effects of initial controlled atmosphere (CA) treatment on quality maintenance of 'Fuji' apples were assessed and compared with 1-methylcyclopropene (1-MCP) treatment and continuous CA storage. Apples were harvested twice at different maturity, treated with 1 ${\mu}L{\cdot}L^{-1}$ 1-MCP and then stored for 8 months at $0^{\circ}C$ under 3 conditions: air, CA for the first month followed by air (initial CA), and continuous CA (full CA). CA storage was performed with 1.5 kPa $O_2$ and < 1.0 kPa ($N_2$ balance). Following long-term storage, export simulation, refrigerated shipment and local distribution, were performed by holding apples at $0^{\circ}C$ for 2 weeks and on the shelf at $20^{\circ}C$ for 7 days. Both the application of 1-MCP and CA storage reduced ethylene production and respiration rates. Initial CA storage was also effective on reducing the metabolism although the effects were not as noticeable as full CA. Full CA storage with or without 1-MCP treatment maintained titratable acidity, flesh firmness, and sensory quality at the acceptable to excellent level even after the export simulation following 8-month storage regardless of harvest maturity. In contrast, effects of initial CA storage were limited to the maintenance of firmness and texture in early-harvested apples. Overall results indicated that harvest maturity is the critical factor for export fruit quality after long-term storage when separate treatment of initial CA storage or 1-MCP treatment is applied as a postharvest program.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.4
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• pp.432-442
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• 2011

Anodized tubular $TiO_2$ electrodes (ATTEs) with three noticeably different lengths are prepared to determine their optimum length for the photo-driven activity in the reaction of Cr(VI) reduction and hydrogen evolution. The ATTEs with ethylene glycol have longer $TiO_2$ tubes (7-15.6 ${\mu}m$) than those with hydrfluoric acid (0.6-0.8 ${\mu}m$). These samples, which differ only in the length of the tubes, with a wall thickness of ca. 20 nm, consist mainly of an anatase crystalline phase after heat treatment at $650^{\circ}C$, since the anatase crystallites at the tube walls do not undergo transformation into rutile phase, due to the constraints imposed by the wall thickness. Among them, the medium size (ca. 8 ${\mu}m$) tubes provide the optimum conditions, irrespective of the light intensity, which is explained in terms of the correlation between the amount of photons and the adsorbed electron acceptors and their location. Photocatalytic Cr(VI) reduction leads to ca. 60% reduction of Cr(VI) even under 1 sun irradiation with the medium-sized anodized $TiO_2$ tubes, but only ca. 20% with the short- and long-sized tubes. For hydrogen evolution, tubes longer than 8 ${\mu}m$ do not exhibit better performance with any light intensity.

• Journal of Practical Agriculture & Fisheries Research
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• v.12 no.1
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• pp.53-62
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• 2010

This study was designed to examine whether 'Hongro' apples packaged with natural calcium-coated package papers was fresher maintained than fruit held in not-packaged tray, and whether postharvest physiology of the fruits was affected by calcium-coated papers, or not. The summarized results were as follows; Soluble solids contents and firmness of fruit were higher room temperature(20~25℃) after 4 week and 14 week in cold storage(0~1℃) by calcium-coated package papers. but total acid contents in juice and Hunter a value of peel were trended to decrease in room temperature and cold storage. Weight loss of fruit, decay fruit and CO₂ evolution were decreased by calcium and wax-coated package papers in room temperature storage condition. Also, excellent fruits increased. Ethylene evolution in fruit were not different by package paper and storage condition.