• Journal of the Korean Applied Science and Technology
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• v.21 no.4
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• pp.300-305
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• 2004

High-solid coatings were prepared by blending of previosly synthesized acrylic resins and hexamethylene diisocyanate-trimer and curing it at room temperature. The characterization of the films of the prepared coatings was performed. The impact resistance, cross-hatch adhesion, $60^{\circ}$specular gloss, and heat resistance of the films proved to be good, and the pencil hardness and drying time proved to be slightly poor. Especially, there was a remarkable improvement in the heat resistance. This improvement may stem from the regular arrangement of ethyl groups introduced into the acrylic resin. As a result of Rigid-body pendulum visco-elasticity measurement, dynamic $T_g$ values of cured films increased with dynamic $T_g$ values.

• Journal of the Korean Wood Science and Technology
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• v.47 no.2
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• pp.200-209
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• 2019

To improve the water resistance of melamine-urea-formaldehyde (MUF) resins, different levels of blocked polymeric 4,4 diphenyl methane diisocyanate (B-pMDI) were blended with MUF resins to prepare B-pMDI/MUF hybrid adhesives, and their adhesion performances were evaluated for the surface lamination of fancy veneer on plywood. FT-IR spectra showed that the de-blocked -NCO groups reacted with the -OH of hydroxymethyl groups of the MUF resins to form urethane bonds at 2% B-pMDI/MUF, which was detected before and after their hydrolysis. The mass loss after the hydrolysis consistently decreased as the B-pMDI level increased, indicating an improvement in the water resistance. As the B-pMDI level increased, the activation energy of hybrid adhesives decreased, which improved the reactivity of the hybrid adhesives. Additionally, the water resistance improvement of the hybrid adhesives increased the tensile shear strength of the surface laminated plywood in semi-water proof and water-proof by 23 % and 8 %, respectively, at 2% B-pMDI level. This was likely due to the urethane linkages in the hybrid adhesives. However, the formaldehyde emission from plywood panels bonded with the hybrid adhesives increased in the dry state, indicating incomplete curing of the hybrid adhesives.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.5
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• pp.139-146
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• 2023

In this study, compressive strength and adhesion strength were measured as repair materials to evaluate the mechanical and electrical properties of compression and shear specimens with self-sensing repair materials. As a result of the experiment, the strength improvement rate of the compression test specimen was higher than the section enlargement area ratio, but the shear test specimen did not show an improvement in strength as much as the section enlargement area ratio. Compression experiments under load showed high correlation between FCR-Strain and FCR-Stress, confirming self-sensing performance. However, the shear test did not show as much correlation as the compression test. Accordingly, it is judged that the self-sensing repair material is suitable for the compression member on which the compression load acts in the building.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.3
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• pp.247-258
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• 2023

This study aims to investigate the enhancement of water resistance and improvement in adhesion to the skin by combining dextrin palmitate and isopropyl titanium triisostearate coating materials with titanium dioxide. Due to the recent increase in consumers who enjoy outdoor activities, the demand for sunscreen with excellent water resistance is increasing. Prior research was conducted with O/W, Pickering, and W/O/W multiple formulations, but there was a limit to water resistance. The purpose of this study is to develop a complex inorganic powder that can improve water resistance and increase adhesion to the skin to solve this problem. First, we combined dextrin palmitate and isopropyl titanium triisostearate coating materials to form a composite with titanium dioxide. The coating of the inorganic powder was confirmed using FE-SEM and FT-IR analysis. The composite exhibited significantly higher in vitro water resistance compared to other formulations. The hydrophobicity of the coated inorganic powder was compared by measuring the contact angles. When the coated inorganic powder was applied to the W/O sunscreen formulation and the non-coated inorganic powder was applied to the W/O sunscreen formulation as a control, the SPF of the sunscreen containing the coated inorganic powder was higher. These results were the same when observed with a UV camera. Finally the adhesion of the coated inorganic powder to the skin was assessed by applying it to a foundation product. In vivo study, it was observed that the product formulated with the coated powder exhibited less smudging compared to the foundation product formulated with the non-coated powder. The developed inorganic powder in this study demonstrated excellent adhesion to the skin, providing a superior sensory experience, as well as enhanced hydrophobicity and remarkable water resistance effects. In the future, the result of this study is expected to help develop various sunscreen products to improve water resistance.

• Journal of Gastric Cancer
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• v.12 no.4
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• pp.249-253
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• 2012

Chronic abdominal pain remains a challenge to all known diagnostic and treatment methods with patients undergoing numerous diagnostic work-ups including surgery. However, the surgical treatment of patients with chronic intractable abdominal pain is controversial. There has been no discussion of the indications for adhesiolysis in cases of obstruction or strangulation of the bowel, and adhesiolysis by laparotomy has never gained acceptance as a treatment modality for chronic abdominal pain. One of the reasons for this lack of acceptance is the high complication rate during and after adhesiolysis. Laparoscopic surgery has been accepted as a technique for diagnostic and therapeutic procedures in general surgery. Laparoscopy allows surgeons to see and treat many abdominal changes that could not otherwise be diagnosed. Here we report two cases of successful symptomatic improvement through laparoscopic adhesiolysis for chronic abdominal pain without intestinal obstruction after total gastrectomy.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.167.2-167.2
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• 2016

금(Au) 및 금의 합금도금은 주로 극히 얇고 색상만 나타내는 정도의 장식용으로 많이 사용되고 있으나 단순한 장식품뿐만 아니고 스마트폰, 정보통신 서버, 전자기기, 자동차, 전지용에도 널리 사용되고 있다. 특히 로켓공업이나 인공위성의 와곽부, 엔진에는 필수적이다. 현재 미국의 금도금액 85%는 전자부품과 인공위성(NASA) 등의 공업용에 사용되고 있다. 금도금의 이용가치는 주로 내식성이며 전기저항이 작고 열전도성이 뛰어나 전기접전부에 필수적으로 사용해야만 한다. 또한 2007년 유럽의 RoHS규정에 의해 피부에 접촉하는 팔찌, 귀걸이, 목걸이, 반지 등의 디자인 액세서리 제품에 있어서도 종래의 6가 크롬이나, 납, 수은, 카드뮴 사용이 금지되었다. 종래의 산성, 알칼리성, 중성 금도금에서는 주로 시안(Cyan) 기반의 전처리 탈지액이 사용되고 있어 작업환경에도 유해하며 생산성 감소로 이어지고 있다. 이에 전해 금도금 전처리 탈지공정을 개선함으로써 품질불량 20%감소와 함께 작업환경 개선으로 생산성 30%향상을 기대할 수 있다.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2000.05a
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• pp.146-152
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• 2000

As an improvement in the standard of living and economic growth the demand for air conditioning equipment is increasing rapidly. Nowadays air conditioning equipments are being used for industry large building house and car. Thess equipments was concentrated on improving heat efficiency of economic aspects while they design heat exchanger for cooling and heating,. These air conditioning equipments using heat exchanger cause a discomfort to user due to generating mist at the beginning of operating. Therefore the user demand air of high class and quality. In this experimental study to acquire elementary data for development of heat exchanger which be able to supply air of high quality that is to say possess a restraint effect of mist generation. We estimate an effect on cooling plate kind supply air velocity supply air temperature cooled plate temperature and supply air relative humidity which have an influence on outlet air condition of heat exchanger.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.10
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• pp.1005-1013
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• 2009

In this paper, the performance improvement of a decentralized brake system for railway rolling stocks is investigated. In order to verify the effectiveness of the decentralized brake system, it is compared to the truck unit brake system which has only one control unit per a truck. The adaptive sliding mode control scheme is used to realize a robust anti-slip brake control system. Through computer simulations, it is verified that the decentralized brake system has better braking performance than the truck unit brake system.

• Journal of Chest Surgery
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• v.15 no.1
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• pp.129-135
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• 1982

Congenital pericardial defect is a rare anomaly, which was first described by M. Columbus in 1559. Four hundred years later the first clinical diagnosis was reported by Ellis et al. The congenital pericardial defect Is usually asymptomatic and Is found Incidentally at thoracotomy and autopsy, but it appears that partial absence of pericardium Is not Innocuous because of sudden death due to herniation of a portion of heart. We experienced congenital left pericardial defect in 20 year old female who was diagnosed as left ventricular aneurysm before operation. This patient complained of dyspnea on exertion and anterior chest discomfortness. Physical examination revealed Grade II pansystolic murmur on the 3rd and 4th intercostal space left sternal border. There were specific abnormal findings on the chest plain film, EKG, ultrasonography, and left ventriculography. On 9th July 1981, an operation was performed and found the left partial pericardial defect through which a large portion of left ventricle was herniated Into left pleural space. The method of operation was removal of adhesion and widening of the pericardial defect to avoid Incarceration. After operation, we observed marked Improvement of symptoms and disappearance of cardiac murmur.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.441-444
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• 2007

In this paper, the resonance characteristics of ZnO-based film bulk acoustic resonator (FBAR) devices with high-quality multi-layer reflectors are proposed. The ultrathin Cr film $(300\;\AA-thick)$ between $SiO_2$ film and W film is formed by a sputtering-deposition in order to enhance the adherence at their interfaces. The resonance frequency was observed to vary with the number of the reflectors. This seems to be attributed to the change in the effective thickness of the ZnO film. Also, increasing the number of layers has led to a significant improvement of the series/parallel quality factor.