• 펄프종이기술
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• 제45권2호
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• pp.13-20
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• 2013

In this study, two biodegradable polymer(PLA, PBS) emulsions were treated on agricultural packaging paper such as fruit bagging paper. Water-repellency, mechanical properties, and SEM image with thermal aging were measured on the emulsion treated fruit bagging paper. Biodegradable polymers(such as poly lactic acid, poly butylene succinate) emulsion treated fruit bagging paper had higher water-repellency and strength than other water-repellent(such as acrylic repellent, linseed oil and paraffin wax) treated fruit bagging paper. According to FE-SEM results of polymer emulsion coated fruit bagging paper, the colloidal particles of emulsion after thermal treatment (looks like being) were adhered to the fibers. Thus, using biodegradable polymer emulsion is expected to protect a fruit for a long time.

• Journal of Welding and Joining
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• 제35권3호
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• pp.15-20
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• 2017

In this paper, two types of assemblies using CNT-filled SACAs (with 0.03 wt% CNTs and without CNT) were prepared to investigate the influence of carbon nanotubes (CNTs) on the reliability properties of solderable anisotropic conductive adhesives (SACAs) with a low-melting-point alloy (LMPA). Two types of reliability test including thermal shock (TS: -55 to $125^{\circ}C$, 1000 cycles) and high-temperature and high-humidity (HTHH: $85^{\circ}C$, 85% RH, 1000 h) tests were conducted. The SACA assemblies with and without CNTs showed stable electrical reliability properties due to the formation of wide and stable metallurgical interconnection between corresponding metallizations by the molten LMPA fillers. Although the mechanical pull strength of CNT-filled SACA assemblies was decreased after thermal aging (because of the excessive layer growth and planarization of the IMCs), the CNT-filled SACA with 0.03wt% CNTs showed enhanced mechanical reliability properties compared with the SACA assemblies no CNTs. This enhancement in mechanical performance was due to the reinforcement effect of the CNTs. These results demonstrate that CNTs within the CNT-filled SACAs can improve the reliability properties of CNT-filled SACAs joints due to their superior physical properties.

• 한국임상수의학회지
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• 제24권2호
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• pp.201-207
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• 2007

The teat cup liner compounds with improved physical property were developed using tri-polymer blend of natural rubber(NR), ethylene propylene diene monomer rubber(EPDM) and butyl rubber, and the changes of the physical properties of compounds were measured under various conditions such as standard, thermal, alkaline detergent and acid solutions aging conditions. The hardness of the new teat cup liner compound 1 was 50 and that of the compound 2 was 51 under standard condition. The tensile strength and elongation of the new compound 1 were $154kgf/cm^2$ and 675% under the standard condition, respectively. Also, those of the new compound 2 were 180 kgf/cm and 634% under the same condition. Their hardness were increased about $2{\sim}6%$ and the tensile strength and elongation were decreased about 10% under the $25^{\circ}C$ water and detergent solutions. Even though the new teat cup liner compounds exhibited so much decreased tensile properties under the $105^{\circ}C$ thermal aged condition, they sustained more stable aged physical properties including tensile strength and elongation than those of imported teat cup liner materials. Consequently, the new teat cup liner compounds would give prolonged lift cycle if they are used as a teat cup liner product.

• Nuclear Engineering and Technology
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• 제51권5호
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• pp.1365-1372
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• 2019

The effects of Y and Ti on the microstructure stability and tensile properties of the reduced activation ferritic/martensitic steel have been investigated. The addition of Y and Ti affected the prior austenite grain size due to the pinning of the inclusions. Ti addition of 0.008 wt% to the steel was intended to promote the precipitation of nano-sized carbides with a high resistance to coarsening. 8Ti14Y exhibited a higher yield strength and a lower DBTT than the other alloys due to the fine grain size and additional precipitation hardening by (Ti, Ta)-rich MX. After thermal exposure at $550^{\circ}C$ for 1500 h, yield strength was dropped significantly in exposed 0Ti13Y. On the contrary, a lower reduction of YS was observed in 8Ti14Y. The $M_{23}C_6$ in 0Ti13Y and 8Ti14Y and MX in 25Ti14Y and 39Ti15Y coarsened seriously during ageing, which could be responsible for the reduction of the tensile properties of alloys.

• 대한안전경영과학회지
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• 제23권3호
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• pp.83-88
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• 2021

Recently, due to the aging of workers and the weakening of the labor base in the automobile industry, research on quality inspection methods through ICT(Information and Communication Technology) convergence is being actively conducted. A lot of research has already been done on the development of an automated system for quality inspection in the manufacturing process using image processing. However, there is a limit to detecting defects occurring in the automotive sunroof sealer application process, which is the subject of this study, only by image processing using a general camera. To solve this problem, this paper proposes a system construction method that collects image information using a infrared thermal imaging camera for the sunroof sealer application process and detects possible product defects based on the SVM(Support Vector Machine) algorithm. The proposed system construction method was actually tested and applied to auto parts makers equipped with the sunroof sealer application process, and as a result, the superiority, reliability, and field applicability of the proposed method were proven.

• 품질경영학회지
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• 제51권4호
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• pp.735-749
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• 2023

Purpose: The purpose of this study is to derive solutions and prevent similar cases from occurring by analyzing the causes of cracks found in temperature cycling tests of rocket motor. Methods: By combining the results of the current state confirmation test, non-destructive test, domestic and foreign rocket motor comparison test, cutting test, and adhesion test according to the number of times to apply mold release agent, a Cause and Effect Diagram analysis was performed to derive the cause of cracks. Results: Through this study, 26 factors that could cause cracking in rocket motors during temperature cycling tests were identified. Through various additional test results, a total of five causes were identified, including chemical and structural design of the joint between the propellant and stress relief insert, omission of procedure in the manufacturing procedures, natural aging due to temperature, and load accumulation due to temperature changes. The fundamental cause was confirmed to be insufficient consideration of the release properties of the propellant and stress relief insert. Conclusion: During the design process, it was confirmed that this could be solved by structurally or chemically designing the insert so that it does not combine with the propellant, or by applying a mold release agent during the manufacturing process.

• 분석과학
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• 제30권5호
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• pp.279-286
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• 2017

범죄현장에서 자주 발견되는 감열지의 표면에 남겨진 잠재지문의 압인순서 결정은 지문의 경시 변화 및 지문 나이의 연구와 밀접한 관계가 있으며, 수사에 있어서 추가적인 정보를 제공할 수 있다. 이를 위한 예비실험으로 2가지의 압인 압력과 시간(second)으로 감열지(일반 영수증과 팩스종이)상에 유류한 시료지문을 1~7일의 경과 후에 일(day)별로 iodine fuming법으로 현출하였다. 가시화된 지문의 이미지를 농도계 이미지 분석을 통하여 압인순서와 상관관계가 있을 수 있는 융선의 평균 면적값의 변화를 분석하였다. 감열지 용지의 종류에 따른 큰 차이는 나타나지 않았으나 3일차까지는 지문 융선의 면적값은 점점 증가하거나 유사한 경향을 보였고 4일에서 7일차까지 점진적으로 감소하였다. 6일과 7일차 지문의 면적값은 1일차의 대략 1/2 이하였다. 또한 겹 지문을 실험 한 경우 6일차, 7일차 경우에는 1~3일차의 지문과의 큰 선명도 차이를 보여 육안 구별가능성을 보였다. 추후 압인 조건에 대한 추가적인 실험은 현재의 방법이 지문의 감열지상 압인순서 결정에 가치 있는 방법임을 증명할 수 있을 것이다.

• 마이크로전자및패키징학회지
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• 제12권2호
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• pp.95-103
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• 2005

42Sn-58Bi 솔더(이하 wt.$\%$에 의한 표기)와 무전해 Ni-P/치환 Au under bump metallurgy (UBM) 간의 계면 반응을 intermetallic compound (IMC)의 형성과 성장, UBM의 감소, 그리고 범프 전단강도의 영향 관점에서 시효 처리 전 후에 어떠한 변화가 생기는 지를 알아보고자 하였다. 치환 Au 층을 $5{\mu}m$ 두께의 무전해 Ni-P ($14{\~}15 at.\%$ P)위에 세 가지 각기 다른 두께, 즉 $0{\mu}m$(순수한 무전해 Ni-P UBM), $0.1{\mu}m$, $1{\mu}m$로 도금하였다. 그 후 42Sn-58Bi 솔더 범프를 세 가지 다른 UBM 구조에 스크린프린팅 방식으로 형성하였다. 범프 형성 직후에는 세 가지 다른 UBM구조에서 솔더와 UBM 사이에 공통적으로 $Ni_3Sn_4$ IMC (IMC1) 만이 형성됐다. 하지만, 이를 $125^{\circ}C$에서 시효 처리를 할 경우 특이하게 Au를 함유한 UBM 구조에서는 $Ni_3Sn_4$ 위로 또 다른 4원계 화합물 (IMC2)이 관찰되었다. 원자 비로 $Sn_{77}Ni{15}Bi_6Au_2$인 4원계 화합물로 확인되었다. $Sn_{77}Ni{15}Bi_6Au_2$ 층은 솔더 조인트의 접합성에 매우 치명적인 영향을 미쳤다. 시효 처리를 거친 Au를 함유한 UBM 구조에서 솔더 범프의 전단 강도 값은 시효 처리 전에 비해 $40\%$ 이상의 감소를 보였다.

• 한국식품영양과학회지
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• 제20권5호
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• pp.447-454
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• 1991

쇠고기 단백질 소화에 미치는 마늘의 영향을 검토하기 위해 마늘첨가량, 숙성기간에 따른 효소소화율 및 소화저해물질(Trypsin Inhibitor, TI)의 변화를 실험하였다. 또한 효소 가수분해물의 gel여과 및 가용성부분의 질소량을 정량하여 단백질의 구조 변화를 확인하였으며, 소화율과 아미노산조성 결과를 토대로 예측소화율(Predicted Digestibility, P-dig.), 계산단백효율비(Computed Protein Efficiency Ratio, C-PER) 및 분별계산단백효율비(Discriminant Computed Protein Efficiency Ratio, DC-PER)를 계산하여 단백질 품질을 평가하였다. 쇠고기단백질 소화율은 첨가되는 생마늘량에 약간 영향을 받으나 최적 참가량은 첨가 후의 가열조건에 의하여 결정된다($96{\pm}1^{\circ}C$, 20분 가열시 쇠고기 : 마늘=100g : 12g, 60분 가열시 쇠고기 : 마늘=100g : 3g) 열변성된 쇠고기에 대한 생마늘의 효과는 없고, 날쇠고기육의 소화에는 생마늘의 효과만 인정되며 이미 가열된 쇠고기육의 소화에는 영향을 미치지 못하였다. 날쇠고기를 $4~6^{\circ}C$에서 숙성시켰을 때, 최대의 소화율을 나타내는 시간은 마늘 첨가량에 따라 달라 날쇠고기 100g에 마늘 3g을 첨가할 경우에는(A) 8시간, 12g일 경우에는(B) 12시간이었다. 마늘과 함께 숙성시킨 쇠고기육은 (A)의 경우 $96{\pm}1^{\circ}C$에서 80분, (B)의 경우 20분 정도 가열했을 때 최대소화율을 나타내었다. Four-enzyme으로 가수분해한 숙성시료에는 2,200 dalton 정도의 저분자량의 peptid가 생성되어 소화가 용이함을 확인했으며, 가용성부분도 소화율에 비례하여 증가하였다. 효소소화율에 비례하여 C-PER은 증가하여 C-PER 2.14(날쇠고기)에서 2.50(마늘과 함께 숙성시킨 시료)로 품질이 개선되었다.

• 한국의류학회지
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• 제44권4호
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• pp.776-787
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• 2020

This study investigated physiological and subjective responses to different types of firefighter station uniforms made with various designs and materials. Six healthy males participated in this study that consisted of 20 min of rest, 30 min of treadmill exercise, and 30 min of recovery in a hot and humid environment (34℃ and 65%RH). The experimental clothing conditions were as follows. 1) a fitted T-shirt and trouser made of 100% polyester (FC-Uniform), and 2) flame retardant T-shirts made of acrylic and cotton as well as trousers with aramid and polyester, designed for overfitting (Control). There were no significant differences in the body temperature, and sweat rate between the two conditions; however, the heart rate with the FC-Uniform was significantly lower than Control (p=.025). The clothing microclimate temperature at the chest of the FC-Uniform was significantly lower than the Control (p=.037), and a difference of 1℃ was maintained until the recovery was complete. There were no significant differences in the subjective responses; however, participants experienced a humidity sensation faster with FC-Uniform in the recovery phase. The results indicate that changes in the design and material of firefighter station uniforms may have a positive influence on reducing the thermal stress of firefighters.