• Korean Journal of Agricultural Science
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• v.25 no.1
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• pp.19-25
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• 1998

This study was conducted to develop an appropriate postharvest technique to extend the shelf-life of an early cultivar, 'Tsugaru' apples. The general quality of stored fruit was more affected by maturity at harvest than postharvest treatments. When firmness and internal quality were considered, fruits harvested at the medium stage of color development showed better results. Between postharvest treatments examined in this study, a simple polyethylene film(PE) wrapping (30um) was excellent on inhibition of weight loss but this treatment revealed no clear effect on other quality factors including firmness and acidity. Ethylene scrubber(ES) in polyethylene wrapping showed a positive effect on keeping fruit quality in general. Especially acid content was higher in fruit stored with PE + ES, thus, fruit seemed to be better in freshness. A physiological disorder was observed regardless postharvest treatments. The symptom was associated with incidence of pitting on surface and breakdown of the effected tissue. And much more symptoms were developed near the calyx end. Thus, future studies concerning 'Tsugaru' storage should include an examination of the optimum storage temperature.

• Applied Chemistry for Engineering
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• v.8 no.1
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• pp.76-83
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• 1997

Blends of thermotropic liquid crystalline polymer(TLCP) with poly(ethylene terephthalate) (PET) were prepared by the coprecipitation from a common solvent. The blends were processed through a capillary die at $287^{\circ}C$ to produce a monofilament. Morphology and mechanical, thermal properties of blends and composites were examined by differential scanning calorimetry(DSC), tensile test, optical microscopy and scanning electron microscopy. Crystallization kinetics of the blends were investigated by the isothermal DSC method. The Avrami analyses were applied to obtain the information on the crystal growth geometry and factors controlling the rate of crystallization. In the blends, liquid crystalline phase did not reveal any significant macrophase separation and thermal degradation at the processing temperature. From scanning electron micrographs of cryogenic fracture surfaces of extruded fibers, the TLCP domains were found to be more or less finely dispersed with $0.1{\mu}m$ to $0.2{\mu}m$ in size. Interfacial adhesion between the TLCP and matrix polymer was excellent. Tensile strength and modulus of TLCP/PET in-situ fiber composites were enhanced with increasing draw ratio and LCP content.

• Polymer(Korea)
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• v.30 no.2
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• pp.118-123
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• 2006

The effect of transesterification on the rheological properties in the melt reactive blending of poly(butylene terephthalate)(PBT) with poly(ethylene terephthalate)(PET) has been studied. The melt viscosity depression in PBT was found in PBT/PET blends due to the intrinsic low melt viscosity of PET compared to PBT. In addition, the thermal degradation in the melt blending and transesterification between two polyesters were considered as other factors fer the lowering of the melt viscosity in the blends. In the PBT/PET blends, calcium stearate was less effective than in PBT as a lubricant, however it accelerated both the thermal degradation and transesterification during melt blending. As a result, further melt viscosity drop was obtained in the reactive melt blending of PBT/PET.

• Food Science and Preservation
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• v.14 no.5
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• pp.511-515
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• 2007

'Ooishiwase' plum (Prunus salicina L.) fruits were harvested at three pre-climacteric stages of ripeness (stages 1, 2, and 3) and treated with 1-methylcyclopropene (1-MCP, $1\;{\mu}L/L$) for 24 hours at $10^{\circ}C$ before storage to evaluate the effectiveness of 1-MCP in extending shelf-life at $10^{\circ}C$. Ethylene production and respiration rates were significantly lower after 1-MCP treatment compared to those of control fruit, throughout the entire storage period. Also 1-MCP delayed plum softening and color changes. However the chemical 1-MCP had no effect on fruit soluble solid content changes, the preservative 1-MCP is an effective tool for quality improvement in plums, and extension of shelf life of the fruit and plums can safely be harvested at stage 3 of ripening, at which time the most desirable organoleptic attributes have been developed.

• 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.

• The Korean Journal of Rheology
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• v.5 no.2
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• pp.144-148
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• 1993

Nylon-6의 내충격성을 개선하기 위한 개질제로써 에틸렌-프로필렌 고무(EPR)와 에 틸렌-아크릴 에스터-무수말레산 공중합체(EAM)를 첨가한 nylon-6/EPR/EAM 블렌드 시스 템의 유변학적 특성을 24$0^{\circ}C$에서 조사하였다. 개질제중 EAM의 점도는 조성물 가운데 가장 낮음에도 불구하고 첨가량을 증가함에 따라 블렌드의 점도는 증가하였다. 또한 EPR(I)의 점 도가 EPR(II)의 점도보다 낮지만 EAM 함량이 증가함에 따라 nylon-6/EPR(I)/EAM의 점도 는 nylon-6/EPR(II)/EAM의 점도보다 높아지는 현상이 관찰되었다. 이러한 특성을 분산상의 morphology 변화와 전단력하에서 변형이 어려워지기 때문인 것으로 해석하였다.

• Journal of the Korean Ceramic Society
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• v.37 no.9
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• pp.921-926
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• 2000

에틸렌과 프로판가스로부터 Ni 및 Ni-Cu의 합금촉매를 사용하는 화학증착반응에 의해 제조한 나노탄소섬유에 충전재로 하고, 환경 친화적인 폴리비닐알코올을 매트릭스로 이용하여 복합재를 제조하여 전자파 차폐효능을 조사해 보았다. 전자파 차폐용 충전재의 중요한 물성치인 전기전도도는 나노탄소섬유의 반응조건에 따라 매우 민감하게 변했는데, 전체적으로 10000 psi 압력에서 4.2~29 S/cm 사이에 분포하였고 합금촉매보다도 순수한 Ni로 제조된 나노탄소섬유의 전기전도도 값이 높았다. 한편, 나노탄소섬유/폴리비닐알코올 복합재의 전기전도도는 Ni:Cu(7:3) 합금촉매에서 제조된 나노탄소섬유를 충전시켰을 때, 가장 높게 얻어져서 충전재의 전기전도도 외에도 비표면적이 중요한 변수임을 알 수 있었다. PVA 양에 대한 나노탄소섬유의 함량이 증가할수록 나노탄소섬유 복합재의 전기전도도는 기하급수적으로 증가했고, 110$0^{\circ}C$에서 1시간 동안 나노탄소섬유의 열처리를 통하여 복합재의 전기전도도는 5~7배 증가하였으며, 전자파 차폐율은 2~3 dB 정도 향상시킬 수 있었다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.2
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• pp.192-198
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• 2006

Treatment effects of grape fruit stem extracts (GFSE) containing trans-resveratrol on the storage property of fresh jujube (Zizyphus jujube) were investigated. Fresh jujubes were packed in different storage containers [polyethylene terephthalate (PET) and polyethylene (PE)], and treated with GFSE containing trans-resveratrol of 10, 30 and 50 ppm, respectively. The storage vessels filled with $N_2$ gas, and stored in refrigerator $(0{\pm}1^{\circ}C)$ during 18 weeks, and then quality characteristics during storage period were analysed. Ethylene gas increased until 8 weeks and decreased afterward. Decaying of jujube started at $6\~8$ weeks in control, but it did at 14 week storage for the fruits at $50\%$ maturity treated with 10 ppm of GFSE and packed in PE vessel. Soluble solid (Brix degree) and total acidity of fresh jujube slightly increased in all the treatments during storage period. Hardness slightly increased until 4 weeks and decreased afterward. Vitamin C content was at the highest content of $86.8\~273.4$ mg/100g for most of treatments at 2 weeks and decreased afterward. Storage stability was higher for $50\%$ maturity fruits than for the $70\%$ maturity, and higher for PE vessels than PET containers. Storage period of fresh jujube in this experiment ranges in $10\~12$ weeks for $50\%$ maturity fruits treated with 10 ppm of GFSE and packed in PE vessel.

• Korean Journal of Plant Resources
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• v.19 no.2
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• pp.331-335
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• 2006

This experiment was conducted to investigate the effect of deep sea water on fruit quality and yield of tomato. In the deep sea water treatments, fruit growth and weight were decreased as the concentration of deep sea water increased. Especially, the fresh weight of second truss was decreased significantly than first truss. Soluble solid content was increased significantly in higher concentration treatment especially at 30mM and 40mM treatment. That was increased more in the first than in the second truss fruits. Most of hexose in fruits were glucose and fructose. The reason of increased glucose and fructose contents was the decline of growth because of salinity stress by deep sea water treatment. however deep sea water treatment increased the lycopene content, especially in 20mM treatment. It is assumed that deep sea water treatment cause induction and promotion of ethylene. The higher concentration of deep sea water to the solution, the eater fruit quality improvement was noticed. However, proportional yield reduction accompanied concentration, 20mM deep sea water improved fruit quality without a significant yield reduction. The Re content was the highest among ginsenosides in all treatments. The contents total of ginsenosides in all treatments, except EC 8 treatment, was higher than those in the controlled treatment. The PT/PD value was 1.31 of the lowest in the EC 8 treatment and was 2.52 of the highest in the EC6 treatment. Rf contents in high increase was detected at all treated ginseng roots.

• Journal of Applied Biological Chemistry
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• v.61 no.1
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• pp.75-78
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• 2018

Ethephon is useful pesticide as ethylene precursor, which is an efficient plant hormone to produce functional secondary metabolites. However, the residual safety of ethephon was not studied on various crops. In here, the dissipation pattern of ethephon residue in soybean leaf was investigated both on the foliar and drenching applications. The biological half-lives of ethephon residues were 26.6, and 21.1 h on the once, and double foliar applications, respectively. Although the residue after three days from the final application was up to $60.6mg\;kg^{-1}$, the residue was below the limit of quantitation on the dried soybean leaf. In addition, drenching application of ethephon could increase the residue up to $36.3mg\;kg^{-1}$ after 20.1 h from the application, however, the treatment would not affect to the total phenol content significantly (p >0.01).