• Composites Research
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• v.17 no.6
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• pp.14-21
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• 2004

Failure process, mode and strength of unidirectional composite single lap bonded joints were investigated experimentally with respect to bonding methods, those are, co-curing with and without adhesive and secondary bonding. The co-cured joint specimens without adhesive had the largest failure strength. Progressive failures along the adhesive layer occurred in the secondary bonded specimens. In the co-cured specimens with adhesive film which had better material strength and adhesion performance, delamination failure occurred and the joint strengths were less than those of secondary bonded specimens. Delamination failure did not occur in the secondary bonded specimens because of earlier crack growth and progressive failure in the adhesive layer. Therefore, failure strength of composite bonded Joints were not always proportionate to material strength and adhesion performance of the adhesive due to the weakness of delamination in composite materials. The effects of surface roughness, bondline thickness and fillets were also studied on secondary bonded specimens.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.1 no.2
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• pp.73-79
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• 1968

The resolving capacities of xanthophyll pigments on thin-layers of Silica Gel, Hyflo super-Cel, and Micro-Cel C with varying concentrations of acetone in petroleum ether as the developing solvent were compared. The results showed that the resolving capacity of Micro-Cel C thin-layer was superior to others and satisfactory for the separation of leaf carotenoids in clearly separated six bands; carotenes, lutein-zeaxanthin, antheraxanthin, violaxanthin, an unidentified band, and neoxanthin, when it was developed with $13\%$ acetone-petroleum ether solution for 15 to 20minutes in an unsaturated chamber. Adhension of Micro-Cel C to glass was adequate without binder. Calcium sulfate used as a binder appeared to inactivate the resolving capacity of Micro-Cel C. Removing an about 0.2cm-wide layer on bo side of thin-layer slide helped to prevent 'edge effect' which gave tailing and faster solvent ascending along the side than the center. An adequate thickness of thin-layer was obtained when a 3 ml aliquot of the suspension in which l0g powdered Micro-Cel C was suspended in 75 ml distilled water was coated on a $2\times20cm$ glass slide.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.9 s.180
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• pp.2246-2251
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• 2000

Adhesive bonding repair methods has been used for a number of decades for construction of damaged structures. In order to evaluate the life of cracked aging aircraft structures, the repair technique which uses adhesively bonded boron/epoxy composite patches is being widely considered as a cost-effective and reliable method. But, this repair method contains many shortcomings. One of these shortcomings, debonding is major issue. When the adhesive shear stress increases, debonding is caused at the end of patch and plate interface. And this debonding is another defect except cracks propagation. In this paper, we assess safety at the cracked AI-plate repaired by Br/Epoxy composite patch. Firstly, from the view of fracture mechanics, reduction of stress intensity factors is determined by the variety of patch feature. Secondly, using the elastic analysis and finite element analysis, the distribution of adhesive shear stresses is acquired. Finally, The problem of how to optimize the geometric configurations of the patch has been discussed.

• Korean Journal of Food Science and Technology
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• v.19 no.2
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• pp.164-170
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• 1987

The microstructure, contents of pectic substances and textural properties of cell masses separated from cooked kindey bean and soybean were investigated. Cooked kidney bean could be easily separated to the individual cells, while soybean yielded mixture of individual cells and cell clusters. The break down of the middle lamella was observed, but cell wall was not injured . Separated cells from kidney bean were spherical, while those from soybean were long sack shape as observed in both optical microscope and SEM. Cooked soybean cell mass, which had higher content of pectic substances, showed higher cohesiveness and adhesiveness compared to kidney bean cell mass.

• The Korean Journal of Mycology
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• v.23 no.1 s.72
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• pp.61-70
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• 1995

The genus Armillaria is important because they produce Gastrodia tubers. Seventy two isolates of Armillaria were obtained from fruit bodies grown on decayed wood in Korea. Twenty four isolates from Pinus koraiensis were identified as A. ostoyae. Two isolates from G. elata growing in the field were identified as A. mellea. Seven isolates from Acer ginnala and Quercus spp. were identified as A. tabescens. Thirty nine isolates were identified as A. gallica. Armillaria gallica was isolated from Quercus spp., Ainus japonica, Vitis amurensis and Prunus sargentii. Armillaria spp. isolates were divided into four groups based on the cultural characteristics. Group II (A. gallica KNU-A110) was better than the other groups for mycelial growth and rhizomorph formation. Isolate KNU-A110 proved to be good for production of G. elata tubers. This fungus forms mycelial fan in the plant tissue and rhizomorphs in contact with G. elata tubers. Gastrodia spp. was found in thirteen sites in Kangweon province in Korea. The plants were divided into three different kinds based on stem color. Plants with stems of brownish orange and greyish yellow were identified as G. elata, and those with greyish green colored stems were identified as G. gracilis. Gastrodia was collected mainly from humus soils rich in leaf debris, and slopes facing south from mid-May to mid-July. Once the new tubers are formed from the ancestry tuber, the ancestry tuber begins to decay. The offspring tuber, apparently gaining nutrients through rhizomorphs, begins to grow in length and slowly to enlarge. It takes three years for the offspring tuber to become ancestry tuber.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.27 no.2
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• pp.63-70
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• 2021

As the government strengthens its policy of separating and discharging packaging materials, consumers are increasingly dissatisfied. In order to increase consumer participation in separate discharge policy of packaging materials, it is necessary to increase the willingness to participate by reducing potential consumer problems such as removal of packaging labels. This study conducted a survey of 300 consumers aged 14 and over who recycle and discharge directly from their homes. Ninety-nine percent of consumers said PET bottles are released separately. However, only 65% of consumers removed labels (attachment labels, shrink labels) and other materials (caps, vinyl coatings, tapes, handles, bases, etc.) during separate discharge process. Nearly 52% of consumers cited 'difficulty of separation' as the main reason for not removing labels and other materials. One-way ANOVA analysis showed that 'strong adhesion', 'removal initiation problem' and 'material strength' had high mean regardless of age, which are major factors impedes label removal. Using shrink labels with perforated lines rather than adhesive labels would be more beneficial to encouraging participation in separate discharge. However, if the shrink labels do not have perforated lines or are difficult to remove, adhesive labels are often easier to remove than shrink labels because of the strong cohesiveness of shrink labels. As a result, how easy it is for consumers to remove the label is more important than technological differences. In order to increase consumer participation in packaging material and label separations, improvements in structural design are needed along with the selection of materials that are easy to separate. This study is meaningful in examining consumer perceptions, deriving problems and suggesting directions for policy improvement.

• Korean Journal of Materials Research
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• v.7 no.7
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• pp.582-586
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• 1997

본 연구에서는 플라즈마 화학 증착법으로 기판에 따른 DLC 박막의 접착력 변화를 조사하였다. 박막의 분리가 발생하기 시작하는 경우의 두께를 임계두께로 정하여 스크래치 테스터로 측정된 임계하중과 더불어 박막의 잡착강도값으로 사용하였다. 다이아몬드상 탄소박막은 실리콘 기판에서 가장 우수한 접착력을 가지는 것으로 나타났으며, 크롬>티타늄>철>세라믹 기판의 순으로 접착력이 감소하였다. XPS, AES 분석을 사용하여 계면에서 결합구조와 결합형태 등을 관찰하여 접착력과의 관계를 조사하였다. 그 결과 다이아몬드상 탄소박막의 접착강도는 막/기판의 계면에서의 탄화물 형성에 영향을 받으며, 계면에서의 초기산화물층에 큰 영향을 받는것을 확인하였다.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2004.05a
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• pp.291-294
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• 2004

본 연구는 EPS 생성 유산균을 이용한 stirred 요구르트 제조의 기초 자료로 활용하고자 실시하였다. EPS 분리 실험결과에서 발효 온도가 낮을수록 더 많은 EPS가 생성하고, 발효 12시간과 24시간에 많은 EPS를 생성하는 것으로 관찰되었다. 점도는 EPS 함량과 무관하게 발효 시간이 증가할수록 증가하였으며, $40^{\circ}C$, 발효 30시간에 가장 높은 점도가 측정되었고, syneresis는 $37^{\circ}C$에서 30시간 발효한 요구르트가 가장 적은 것으로 관찰되었다. 경도와 접착성은 발효가 진행될수록 증가한 반면에 점착성과 탄력성은 발효가 진행될수록 감소하였으며, 관능검사 결과에서는 $37^{\circ}C$, 24시간 발효한 요구르트가 가장 높은 수치를 나타내었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.1681-1684
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• 2015

최근 소형 모바일 디바이스가 발달함에 따라 시간적, 공간적 제약이 없이 대량의 콘텐츠가 소비되고 있는 환경에서 콘텐츠 소비 만족도 및 몰입도를 측정하기 위해 사용자 피드백을 설문 조사하는 기존 방식은 비효율적이다. 왜냐하면 수작업에 의존하고 객관성이 결여된 데이터가 수집될 가능성이 있기 때문이다. 따라서 최근 연구에서는 EEG를 활용한 방법이 하나의 대안으로 제시되고 있다. 본 논문에서는 기존 설문조사 방식의 한계점을 보완하고 기존 EEG방식의 단점을 개선하기 위한 포터블 EEG를 활용하는 방법을 제안하였다. 소형 및 간편함을 확보하기 위하여 배터리 환경에 비 접착식 단일전극을 이용하여 EEG를 측정하고 주파수 분석을 통하여 집중력과 관련된 파형을 분리, 콘텐츠 몰입도를 점수화 하였다. 마지막으로 실험을 통해 앞서 산출한 점수와 콘텐츠의 흥미도가 비례관계에 있음을 증명하였다.

• Journal of Adhesion and Interface
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• v.14 no.2
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• pp.82-87
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• 2013

Preliminary studies on the synthesis of magnetic nanoparticles including nanoporous carbon materials have been done via a direct carbonization process from resol, ferric nitrate and triblock copolymer F127. The results show that the nanoporous magnetite/carbon ($Fe_3O_4$/carbon) with a low $Fe_3O_4$ content (1 wt%) possesses an ordered 2-D hexagonal (p6mm) structure, uniform nanopores (3.6 nm), high surface areas (up to 635 $m^2/g$) and pore volumes (up to 0.48 $cm^3/g$). Magnetite nanoparticles with a small particle size (10.2 nm) were confined in the matrix of amorphous carbon frameworks with superparamagnetic property (7.7 emu/g). The nanoporous magnetite/carbon showed maximum adsorption amount (995 mg/g) of ibuprofen after 24 h at room temperature. The nanoporous magnetite/carbon was separated from solution easily by using a magnet. The nanoporous magnetite/carbon material is a good adsorbent for hydrophobic organic drug molecules, i.e. ibuprofen.