• Korean Journal of Agricultural Science
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• v.38 no.2
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• pp.205-212
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• 2011

The potential factors for quality loss of cleaned fresh ginseng and technology to be associated with the improvement of marketability through pre-packaging fumigation were examined. Major microorganisms isolated from fresh ginseng included Botrytis cinerea, and Erwinia sp. Others such as Cylindrocarpon sp., Fusarium spp., Pennicilium spp., Bacillus spp. were also found at relatively low frequency. The bacterial density of vacuum packaged fresh ginseng rapidly increased during simulated marketing. Little correlation between bacterial growth and package swelling was found. In order to improve packaging method of fresh ginseng, pre-packaging treatment of 2-phenylethyl alcohol (PE, 100 uL/L, 4 hr) was examined. The fumigation treatment effectively inhibited the growth of bacteria density and also effective on keeping firmness of ginseng root, especially in cortical portion. The internal gas compositions of plastic container packaged for ginseng were approximately ranged between 6 to 8% $O_2$and 3 to 4% $CO_2$. The $O_2$ level of fumigation treatment was lower than control whereas $CO_2$ level was higher. The upsurge of ethylene evolution I day after simulated marketing was found only in fumigation treatment but it returned to ordinary level at day 2. The sucrose content of 2-PE treatment was significantly reduced at 5 days after simulated marketing but reducing sugars like glucose and fructose remained at higher level. The difference in sugar levels was reduced after 10 days of simulated marketing. The decay of fresh ginseng began at the lateral or fine root, which is weak to physical damage, in general. The epidermis was more damaged. Plastic container packaging with PE fumigation could be an alternative to vacuum packaging, which allows an aerobic environment and prevents anaerobic respiration. Further study of pre-package fumigation is required to improve technology of fresh ginseng marketing.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.441-447
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• 1999

Changes in flavor characteristics of roasted coffee in 6 package models during storage were investigated by GC/MS analysis and sensory evaluation to establish the criteria of the shelf-life of the roasted coffee in three flavor quality-'fresh', 'satisfying' and 'minimally acceptable' levels. In direct headspace method of GC/MS, 47 volatile compounds were analyzed and the light volatile compounds were reduced sharply at initial stage of storage and faster in the package with air. The correlation between % retention of 2,3-butanedione and overall aroma of roasted coffee showed good linear-relation, of which correlation coefficient (R) were from 0.999 to 0.904 depending on package models, indicating that 2,3-butanedione would be an index chemical for evaluating the freshness of roasted coffee. In sensory evaluation of 6 package models during storage, roasted whole beans (RB) and roasted and ground (RG) coffee in air-package were preserved in 'fresh quality' for $0.5{\sim}1$ week, 'satisfying quality' for $2{\sim}3$ weeks and 'minimally acceptable quality' for 12 weeks, while roasted whole beans in valve-package and roasted and ground coffees in vacuum-package, nitrogen-package and oxygen absorbent-package were preserved in 'fresh quality' for $2{\sim}4$ weeks, 'satisfying quality' for $12{\sim}24$ weeks and 'minimally acceptable quality' for 52 weeks. The oxygen absorbent-package was slightly less effective than other three methods.

• Korean Journal of Food Science and Technology
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• v.28 no.1
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• pp.190-196
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• 1996

Kimchi vacuum packaged in PET/AI/PE pouch was stored at $0^{\circ}C\;and\;10^{\circ}C$ to evaluate the effect of vacuumizing conditions on quality changes. The quality of kimchi during storage was investigated in terms of pH, titratable acidity, color, viable counts of lactic acid bacteria including Leuconostoc and Lactobacilli and sensory properties. Titratable acidity and pH were not significantly different for the vacuum degrees. Color index (L b/a) values of crushed kimchi juice decreased exponentially and remained constant during storage, but the resulting color change was not affected by the vacuum degrees. Viable counts of lactic acid bacteria and sensory scores exhibited no significant difference among the kimchi of different vacuum degrees. Consequently, the vacuum degree in packaging of kimchi seemed to influence little on quality of kimchi. For enhancing the commercial value of vacuum packaged kimchi products, it would be appropriate to produce a slight vacuum, eliminating the head space, within packages.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.873-878
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• 2000

Semiconductor packaging technology is changed rapidly according to the trends of the micro miniaturization of multimedia and information equipment. For I/O limitation and fine pitch limitation, DIP and SOP/QFP are replaced by BGA/CSP. This is one of the surface mount technology(SMT). Solder ball is bumped n the die pad and connected onto mounting board. In ball bump formation, vacuum suction type ball alignment process is widely used, However this type has some problems such as ionization, static electricity and difficulty of fifo(first-input first-out) of solder balls. Seesaw type is reducing these problems and has a structural simplicity and economic efficiency. Ball cartridge velocity and ball aligned plate angle are Important variables to improve the ball alignment Process. In this paper, seesaw-type CSP solder ball loader is developed and the optimal velocity and plate angle are proposed.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.13 no.3_4
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• pp.97-102
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• 2007

A Korean seasoned meat product, seasoned bulgogi was developed in processing and packaging for improved convenience and extended shelf life. The optimal process conditions were found to consist of aging for $20{\sim}30$ hours at $5^{\circ}C$ and air heating for 20 minutes at $210^{\circ}C$ Aging of 24 hours could attain soft texture with little change in pH, color and total aerobic bacterial count. Appropriate drip level could be achieved at air heating of 20 minutes at $210^{\circ}C$, while the air heating at $180^{\circ}C$ could not give suitable level of texture. Modified atmosphere packaging of 60% $CO_2$ and 40% $N_2$ could preserve the product significantly better compared to control of air package and vacuumed package.

• Korean Journal of Food Science and Technology
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• v.30 no.5
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• pp.1179-1183
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• 1998

Effects of gamma irradiation on beef spoilage were investigated by determination of the peroxide value, TBA value and total volatile basic nitrogen for 10 days at $4^{\circ}C$ or $25^{\circ}C$ after gamma irradiation up to 5 kGy in air or vacuum package. The total lipid contents were $4.4{\sim}4.7%$ and were not significantly changed by gamma irradiation up to 5 kGy. The peroxide value and thiobarbituric acid value increased with the elapse of the storage period. The level of lipid oxidation was higher at $25^{\circ}C$ than at $4^{\circ}C$ and higher in air package than in vacuum package and increased depending on the incremental irradiation doses level. Volatile basic nitrogen showed a lower content in the vacuum packaged samples irradiated at $3{\sim}5\;kGy$ than in non-irradiated samples over the storage period.

• Food Science and Preservation
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• v.20 no.3
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• pp.317-322
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• 2013

This study was conducted to investigate the effects of pretreatment and different packaging methods on the physicochemical properties of cold vacuum-dried peaches. All the dried peach samples were stored such as $N_2$ gas substitution, vacuum and passive packaged with polyethylene (PE) film and oriented polypropylene (OPP)/aluminum (Al)/PE film at $40^{\circ}C$ for 50 days. The weight change, pH, soluble solids content, titratable acidity, soluble solid-acid ratio (SS/TA), delta E, browning degree and phenolic compounds were analyzed. The weight change and pH were lower in the 0.1% vitamin C-treated group and were significantly lowest in the vacuum-treated OPP/AL/PE. The soluble solids content and the SS/TA were higher in the non-treated groups than in the vitamin C-treated groups. According to the packaging methods, the $L^*$ values were higher in the vacuum, $N_2$ gas and passive package, in that order. In addition, the browning degree and the delta E value were lower in the pretreated groups and significantly lowest in the vacuum-treated OPP/AL/PE with 0.1% vitamin C group. The phenolic compounds were high for the pretreated groups, according to the packaging methods (vacuum > $N_2$ gas> passive), and the OPP/AL/PE was significantly higher than the PE. These results suggest that different packaging materials and pretreatment methods affected the quality of the dried peaches, and the vacuum-OPP/AL/PE film packaging group showed a high quality.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.808-810
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• 2002

Higher current-rating and improved thermal performance are being sought for existing medium-voltage vacuum circuit breakers(VCB) in order to meet market needs which require to be compact and downsized. In this paper, thermal performance of medium voltage vacuum circuit breaker was investigated through experiments and numerical analysis. We changed several major parameters of current-rating and heat sink affecting on thermal behaviors in the breaker and observed the results. To predict the temperature distribution in complex three-dimensional (3-D) VCB components and gas, the commercial package was used to simulate conjugate heat transfer. Although some assumptions and simplifications were introduced to simulate the model, results from the computational model were in good agreement with actual temperature rise measurements obtained from experiments.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.127.2-127.2
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• 2016

연구된 Si위의 흡착원자들의 확산 메커니즘들에 비해 Ge 표면에서의 확산 메커니즘은 잘 알려져 있지 않다. 최근 연구에 따르면, 수소가 덮인 Ge(110) 표면에서 그래핀 결정 핵생성은 비등방적이며, 낟알 둘레없이 웨이퍼 크기로 성장시킬 수 있음을 보였다. 본 연구에서는 VASP(Vienna Ab-initio Simulation Package)의 NEB(Nudged Elastic Band) 방법을 이용하여 수소가 덮인 Ge(110) 표면과 청결한 표면에서 탄소원자의 확산 과정과 확산에 따른 에너지 장벽을 계산 하였다. 계산 결과 수소가 덮인 표면에서의 탄소원자 확산은 체인 방향으로 각각 3.29 eV, 2.67 eV의 에너지 장벽을 가지고 청결한 표면에서는 탄소원자가 게르마늄 연결을 치환하며 확산한다. 이때 에너지 장벽은 0.82 eV이고 치환된 게르마늄이 확산할 때는 각각 0.64 eV, 0.59 eV의 에너지 장벽을 넘어야 한다. 결과적으로 수소가 덮인 표면에서보다 청결한 표면에서 탄소 확산 에너지 장벽이 낮으며, 청결한 표면에서는 탄소가 게르마늄을 치환하고 치환된 게르마늄이 확산할 확률이 높음을 알 수 있었다.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.127.1-127.1
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• 2016

Si은 값싸고 넓은 시설기반을 갖추고 있어, 발전산업에서 태양광소자의 주원료로 널리 사용된다. 하지만 Si은 간접 띠틈을 Si의 특성을 개선하기 위해 최근 Si에 특정한 결함을 넣어 직접 띠틈으로 바꿔 광효율을 높이려는 시도가 있다. 2015년 초 Si단결정[111]으로 Seiwatz-chain 형태의 결함이 있다면 결함이 있는 Si(111)에 직접 띠틈이 생길 것 이라고 이론적으로 예상했다. 이러한 구조의 제작방법으로 Ca/Si(111)과 Si(111)을 접합 후 가열하여 Ca을 빼내는 방법을 제시했다[1]. 본 연구에서는 이 제작방법 외에 Ca/Si(111)-$2{\times}1$ 표면에서[2] 에피성장으로 결함이 유지된 Si단결정 형성가능성을 제일원리 계산을 통해 연구했다. 제일원리 계산방법으로는 VASP(Vienna Ab-initio Simulation Package)를 이용하였다. Si원자 한개, 두 개, 세 개가 흡착될 경우 원자당 흡착에너지는 각각 3.73 eV, 3.73 eV, 3.91 eV 였다. 따라서 Si원자는 무리형태로 흡착될 것으로 예상되어 결함을 유지하며 단결정으로 성장하기는 어려울 것으로 보인다.