• Korean journal of applied entomology
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• v.45 no.3 s.144
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• pp.363-369
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• 2006

Effects of three packing materials and exposure time on the mortality of Plodia interpunctella and Tribolium castaneum were studied using $CO_{2}-modified$ atmosphere control. Materials used were triple layered craft paper (KKK), triple layered craft paper with one laminate coating layer (KLK), and triple layered craft paper with one HD film coating layer (KHK). In the test balls (${\phi}1.2\;m$) containing 85% $CO_{2}-modified$ atmosphere, concentration of $CO_{2}$ in small packing envelopes ($9.8{\times}9.8cm$) made of the materials after one day was higher in KKK ($26.67{\pm}0.58%$) than KLK ($23.33{\pm}0.58%$) or KHK ($20.67{\pm}0.58%$). Both P. interpunctella and T. castaneum showed higher mortality in KKK than in either KLK or KHK Similar results were obtained by larger space ($9{\times}4{\times}3m$) and packing volume (20 kg) studies. The effect of the packing materials was clearer on T. castaneum more tolerant to $CO_{2}$ than P. interpunctella. Regression of the insect mortality on cumulative concentration time (${\int}_{0}^{t}c{\times}tdc{\approx}{\sum}concentration{\times}time$) was highly significant. Control of P. interpunctella and T. castaneum by $CO_{2}-modified$ atmosphere were discussed in relation to packing materials, cumulative concentration time of $CO_{2}$ and food products.

• Proceedings of the KWS Conference
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• 2010.05a
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• pp.80-80
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• 2010

전자제품의 소형화, 경량화, 고집적화가 심화됨에 따라 전자제품을 구성하는 회로의 미세화 또한 요구되고 있다. 이러한 요구는 경성회로기판 (rigid printed circuit board, RPCB) 뿐만 아니라 연성회로기판 (flexible printed circuit board, FPCB) 에도 적용되고 있으며 이에 대한 많은 연구 또한 이루어지고 있다. 연성회로기판은 일반적으로 절연층을 이루는 폴리이미드 (polyimide, PI)와 전도층을 이루는 구리로 이루어져 있다. 폴리이미드는 뛰어난 열적 화학적 안정성, 우수한 기계적 특성, 연속공정이 가능한 장점을 가지고 있으나, 고온다습한 환경하에서 높은 흡습성으로 인해 전도층을 이루는 구리와의 접합특성이 저하되는 단점 또한 가지고 있다. 또한 전도층을 이루는 구리는 고온다습한 환경하에서 산화 발생이 용이하기 때문에 접합특성의 감소를 야기할 수 있다. 따라서 본 연구에서는 고온다습한 조건하에서 sputtering and plating 공정을 통해 순수 Cr seed layer를 가지는 연성회로기판의 seed layer의 두께와 시효시간의 변화로 인해 발생하는 접합특성의 변화를 관찰하고 분석하였다. 본 연구에서는 두께 $25{\mu}m$의 일본 Kadena사(社)에서 제작된 폴리이미드 상에 sputtering 공정을 통해 순수 Cr으로 이루어진 각각 두께 100, 200, $300{\AA}$의 seed layer를 형성한 후 전해도금법을 이용, 두께 $8{\mu}m$의 구리 전도층을 형성한 시료를 사용하였다. 제작된 시료는 고온다습한 환경하에서의 접합 특성의 변화를 관찰하기 위하여 $85^{\circ}C$/85%RH 항온항습 조건하에서 각각 24, 72, 120, 168시간 동안 시효처리 한 후, Interconnections Packaging Circuitry (IPC) 규격에 의거하여 접합강도를 측정하였다. 시료의 전도층은 폭 3.2mm 길이 230mm의 패턴을 가지도록, 절연층은 폭 10mm, 길이 230mm으로 구성되었으며 이를 50.8mm/min의 박리 속도로 각 시편당 8회의 $90^{\circ}$ peel test를 실시하였다. 파면의 형상과 화학적 조성을 분석하기 위해 SEM (Scanning electron microscope)과 EDS (Energy-dispersive X-ray spectroscopy)를 사용하였으며, 파면의 조도 측정을 위해 AFM (Atomic force microscope)을 사용하였다. 또한 계면의 화학적 결합상태를 분석하기 위해 XPS (X-ray photoelectron spectroscopy)를 통해 파면을 관찰 분석하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.6
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• pp.567-573
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• 2015

This paper aims to evaluate the variation in the mechanical properties of carbon/epoxy composites under in situ low- and high-temperature environments. In situ low- and high-temperature environments were simulated with temperature ranging from $-40^{\circ}C$ to $220^{\circ}C$ using an environmental chamber and furnace. The variation in the mechanical properties of the composites was measured for longitudinal and transverse tensile properties, in-plane shear properties and interlaminar shear strength. Under the low temperature of $-40^{\circ}C$, all mechanical properties increased moderately compared to the baseline properties measured at room temperature. The changes in the longitudinal tensile properties decreased moderately with increasing temperature. However, transverse tensile properties, in-plane shear properties and interlaminar shear strength each showed a significant drop due to the glass transition behavior of the matrix after $140^{\circ}C$. Notably, the tensile property value near $100^{\circ}C$ increased compared to baseline property value, which was an unusual occurrence. This behavior was a direct result of post-curing of the epoxy resin due to its exposure to high temperature.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.6
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• pp.971-976
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• 2002

Effect of storage temperature and packing method on the changes in pH, acidity, the levels of lactic acid bacteria, volume expansion of packages and the colorness during the fermentation of kakdugi (diced radish kimchi) were investigated. The fermentation characteristics were greatly influenced by the temperature. The pH of kakdugi fermented at 15$^{\circ}C$ was 4.10 at 3 days, while the pH of kakdugi fermented at $0^{\circ}C$ was 4.03 at 18 days. The acidity of kakdugi fermented at $0^{\circ}C$ very slowly increased compared to that of the kakdugi fermented at 15$^{\circ}C$, 1$0^{\circ}C$ or 5$^{\circ}C$. The required days to reach the acidity of 0.6% (optimally ripened state) were 6 days at 15$^{\circ}C$, 7 days at 1$0^{\circ}C$, 18 days at 5$^{\circ}C$ and 30 days at $0^{\circ}C$. Despite of different fermentation temperature, the numbers of Leuconostoc sp. in optimally ripened kakdugi were similar. However, Lactobacillus sp. in kakdugi fermented at $0^{\circ}C$ was the smallest in number. Also, the volume expansion of aluminum pack was the lowest in kakdugi fermented at $0^{\circ}C$. Both pH and acidity of the kakdugi fermented in different packing condition did not show any difference at 1$0^{\circ}C$ for 20 days, however, the color of the kakdugi was affected by a packing method. Aluminium laminate package in which Ca(OH)$_2$ Pack stuck inside resulted in decolorization of kakdugi compared with aluminum package without Ca(OH)$_2$ pack or plastic jar. It showed the lowest redness and the highest lightness and yellowness. These results indicated that fermentation at $0^{\circ}C$ could increase storage period of kakdugi with minimum growth of Lactobacillus sp., and plastic jar might relieve the problem of volume expansion and decolorization of kakdugi.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.75-75
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• 2009

연성회로기판은 일반적으로 절연체를 이루는 폴리이미드와 전도체를 이루는 구리로 구성되어 있다. 폴리이미드는 뛰어난 열적 화학적 안정성, 기계적 특성, 공정성 등의 장점으로 인해 연성회로기판의 절연체로서 제안되었지만 전도체를 이루는 구리와의 접합 특성이 우수하지 않기 때문에 많은 연구가 현재까지 진행되고 있고, 그 결과 연성회로기판의 접합 특성에 많은 개선이 이루어짐과 동시에 다양한 공정 방법이 제안되고 있다. 하지만 고온다습한 환경에서 사용될 경우 폴리이미드의 높은 흡습성과, 구리와 seed layer의 산화 문제로 인해 접합 특성이 저하된다는 단점 또한 가지고 있다. 따라서 본 연구를 통해 고온다습한 조건하에서 seed layer가 80Ni/20Cr 합금으로 구성된 연성회로기판의 seed layer의 두께와 시효시간으로 인해 발생하는 접합 신뢰성의 차이를 관찰하였다. 본 연구에서는 두께 $25{\mu}m$의 폴리이미드 위에 각각 100, 200, $300{\AA}$ 두께의 80Ni/20Cr의 합금 조성을 가지는 seed layer를 스퍼터링 공정을 통해 형성한 후 전해도금법을 이용하여 $8{\mu}m$ 두께의 구리 전도층을 형성하였다. 접합 특성 평가를 위해 ICP 규격에 따라 전도층 패턴을 폭 3.2mm, 길이 230mm로 시편을 제작하여 50.8mm/min의 이송 속도로 각 시편당 8회의 $90^{\circ}$ peel test를 실시하였다. 또한 $85^{\circ}C$/85% 항온항습 조건하에서 각각 24, 72, 120, 168시간 동안 시효 처리 후 같은 방법으로 연성회로기판의 접합 특성을 평가하였다. 파면의 형상과 조성을 분석하기 위해 SEM (Scanning electron microscope)과 EDS (Energy-dispersive X-ray spectroscopy)를 사용하였으며, 파면의 조도 측정을 위해 AFM (Atomic force microscope)을 사용하였다. 또한 파면의 잔여물 분석을 위해 EPMA (Energy probe microanalysis)를 사용하였고 계면의 화학적 결합상태를 분석하기 위해 XPS (X-ray photoelectron spectroscopy)를 통해 파면을 분석하였다.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.21 no.1
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• pp.75-81
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• 1985

The tensile and dielctric strength of the epoxied resin with bi-directional woven glass fibers with a laminate of two layers(G-10) are studied, and the test parameter is the angle between fiber orientation and the tensile axis. The obtained results may be summaried as follows: 1) when the angle between fiber orientation and tensile axis was varied from 0$^{\circ}$ to 45$^{\circ}$ the yield and fracture stresses have a tendency to decrease with increase in the angle. Especially, the decrease rates in the yield and fracture stresses are changed remarkably in the range of 0$^{\circ}$ to 15$^{\circ}$. 2) The fracture strain has showed the maximum value when the angle between fiber orientation and tensile axis is 45$^{\circ}$, and showed the rapid rate of change from 15$^{\circ}$ to 45$^{\circ}$. 3) For the sample with same angle between fiber orientation and tensile axis the maximum dielectric strength under compressive stress is decreased with increase in tensile stress, when the compressive stress is increased as a parameter of tensile stress. 4) When the angle between fiber orientation and tensile axis is 45$^{\circ}$, the dielectric strength showed the worst value, as the mechanical strength did.

• Journal of the Korean Geotechnical Society
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• v.27 no.12
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• pp.107-116
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• 2011

Rigid soil containers (or rigid boxes) are often used for 1g shaking table tests. The rigid boxes, however, do not accurately simulate the amplification of ground acceleration and phase difference of seismic motion in the model ground due to the confinement of shear deformation and the reflection of seismic wave at the box walls. Laminar soil containers (or laminar shear boxes) can simulate the free field motion at convincingly superior accuracy than the rigid ones. In this study, the soft ground is modeled for both types of boxes and is subjected to seismic loading using a 1g shaking table. The comparison of the results using the two types of soil containers illustrates that, in case of the rigid box, the ground acceleration shows non uniform distribution and the phase synchronization of input motion. Whereas, the dynamic behavior of the laminar shear box shows good agreement with the free field behaviors such as the amplification of ground acceleration and the occurrence of phase difference.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.1
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• pp.1-14
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• 2005

Statement of problem. Among the physical properties of adhesion luting cement, the aspect that requires the most important factor is the degree of solubility and water sorption. Dissolution or an inadequate due to excessive water sorption inside the oral cavity compromises the while concurrently increasing the susceptibility to secondary dental caries. Susceptibility to dissolution and difficulty of removing remnant cement from the gingival sulcus have hindered the use of dental resin cement in the clinical practice, but the improved characteristics of newer generation resin cements have interest in and enabled resin cements to be widely used in adhesion of fixed prosthesis, such as laminate veneers and all-ceramic crowns. Purpose. The purpose of this study is to compare and analyze the degrees of solubility and water sorption of a variety of resin cements widely used for clinical purposes with different curing methods. Material and methods. Self-curing resin cements, $Avanto^{(R)}$, $C&B^{TM}$ CEMENT and Superbond C&B cements comprised group 1, 2 and 3. The dual-curing resin cements $Panavian^{TM}$ F, $Calibra^{(R)}$ and $Variolink^{(R)}$ II were divided into groups 4, 5, and 6, respectively. The investigation was carried out using disc-shaped specimens as specified by ANSI/ADA Specification No. 27. The degree of water sorption, water solubility and lactic acid solubility of each test group was analyzed statistically leading to the following conclusion. Results. The degree of water sorption was shown to increase in the following order : group 6, 5, 4, 2, 1 and 3. There were significant differences between the water sorption of each group. Results of the degree of water solubility were shown to increase in the following order : group 6, 5, 4, 2, 1 and 3. Statistically significant differences were found between each group, with the exception of groups 1 and 3. Finally, the degree of lactic acid solubility was found to increase in the following order : group 6,5,4,2,3 and 1. Significant differences were found between each group. In general dual-curing resin cements displayed substantially lower values than self-curing resin cements with regard to water sorption, water solubility, and lactic acid solubility. Conclusions. From the results of this study, dual-curing resin cements show a significantly lower degree of water sorption and solubility than their self-curing counterparts. Clinically, when selecting resin cements, the product with a lower degree of water sorption and solubility are preferred. The results of this study indicate that the use-of dual-curing resin cements is preferable to self-curing cements.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.21 no.1
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• pp.19-26
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• 2015

The carton for liquid products are divided into 'gable top carton' and 'aseptic carton'. Currently, these packages are being recycled in the toilet tissue manufacturing process. The recycling of the carton aluminium laminate is the most important problem facing the recycling procedure of the carton packages due to the reduction in quality of recycled materials. The polymer structure with synthetic resins being used mainly in beverage packaging is also one of the important factors for the procedure for its recycling. The objective of this study was to investigate the package material and structure of the carton for liquid products through marketing research and suggest the supplementation in the work processes of production, use, and recycling. The results represent to improve the recycling profit and the quality of recycled materials when a laminated aluminium of carton for liquid products is replaced to the transparent polymer film. The improvement of the sorting and recycling process may help their recycling efficiencies. In addition, the limited use of synthetic resin molded packaging and increase of wood-pulp collection rate will provide the improvement of the recycling profit and the quality of recycled materials.

• Korean Journal of Food Science and Technology
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• v.37 no.1
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• pp.142-146
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• 2005

Soy protein isolate (SPI) film was laminated with corn zein or wheat gluten to improve functional properties. Both SPI/corn zein-laminated film (Film B) and SPI/wheat gluten-laminated film (Film C) showed increased tensile strength by 150%, compared to control (Film A). Film C showed significant 253% increase in percentage elongation. Water vapor permeability (WVP) of Films B and C decreased slightly compared to Film A. Solubility values of Films B and C were lower than that of Film A. Hunter color values of Films A and C were not significantly different, while Film B showed yellowness due to presence of corn zein. These results suggest SPI/wheat gluten-laminated film is suitable as packaging material.