AE에 의한 용사코팅 부식재의 박리해석

김귀식,손창환,홍용의,현창해 제주대학교 공과대학 첨단기술연구소 2003 尖端技術硏究所論文集 Vol.14 No.2

This paper is to investigate the adhesiveness between substrate and coating layer and the effect of corrosion by acoustic emission method in tensile loading. The used powders are Zn and Al. There are coated on brass alloy substrate, respectively. AE signals of Zn and A1 coating layer increase drastically in strain 2%. but that of Zn specimen have more than that of Al specimen. When the specimens axecuted under 3.5% NaCl solution for 500 hours, the salt solution penetrated into the surface of the substrate through pore of the coating layer. Corrosion production formed on the surface of substrate. The adhesiveness between coating layers is weaken by the polarization and corrosion itself. The AE events, count and energy of corroded coating specimens decreased in comparison with specimens without corrosion. Especially Zn specimen deoreased more than Al specimen in strain 2%.

흡착법을 이용한 어유의 탈취

김귀식,배태진 한국생명과학회 2003 생명과학회지 Vol.13 No.3

어유의 탈취장치 대신 컬럼에 활성탄, 활성 알루미나, 실리카겔, 대나무 숯 등 흡착제를 단독 혹은 적당한 비율로 혼합하여 충진시켜 탈색과 동시에 탈취시킴으로서 효율적인 탈취효과를 검토하였다. 대멸치유의 탈검효과는 수산 30%를 어유 100 ml에 대하여 18 ml첨가한 것이, 탈산은 수산화 나트륨을 2.5%로 하여 $40^{\circ}C$에서 30분간 처리한 것이 효과적이었다. 탈취의 경우 흡착제(활성탄, 활성알루미나, 실리카겔)를 농도별로 단독 첨가할 경우는 실리카겔30% 첨가가, 그리고 흡착제를 혼합하여 첨가할 경우는 활성알루미나 30%와 실리카겔 10% 혼합 첨가가 가장 우수하였으나 흡착제에 녹차분말 2%를 첨가할 경우 큰 효과가 없었다. 대멸치유의 탈검, 탈산 및 탈취 후의 주요지방산 조성은 16:0, 20:5n-3, 18:1n, 16:1n-7, 22:6n-3 및 18:0이었다. 대멸치 정제유에 $\alpha$-tocopherol를 첨가하여 $25^{\circ}C$에서 40일간 저장시 산화 안정성은 대조구는 20일까지 항산화제를 첨가한 경우는 30일까지라 생각되며 $\alpha$-tocopherol 0.02%첨가보다 0.01% 첨가가 더 효과적이었다. Instead of deodorization appararus of fish oil, an adsorbent such as activated charcoal, activated alumina, silicagel, bamboo charcoal was packed in column alone or mixed with preparative ratio, and then test the effective deodorization with bleaching. In the progress of degumming, the effective method was 18 ml of 2.5% oxalic acid per 100m1 of crude large anchovy oil. The optical condition to deacidified was treating for 30 min at $40^{\circ}C$ with 2.5% sodium hydroride solution. The effective deodorization was added with 3% silicagel under the alone treating adsorbent, and mixed treating was 30% activated alumina and 10% silicagel but added to green tea powder was not effective. The major fatty acid of total lipid were 16:0, 20:5n-3, 18:1n-9, 16:1n-7 and 22:6n-3 after treatment of degumming, deacidfication and deodorizing in the large anchovy oil. The oxidative stability of refined anchovy oil added to $\alpha$-tocopherol was validated 20 days under the control, and 30 days in the case of $\alpha$-tocopherol. The 0.01% $\alpha$-tocopherol was more effective than 0.02% $\alpha$-tocopherol.

초・중・고등학생의 인공지능 윤리의식의 성차 분석

김귀식,신영준 경북대학교 과학교육연구소 2021 科學敎育硏究誌 Vol.45 No.1

The purpose of this study is to analyze the gender differences of elementary, junior high, and high school students in the artificial intelligence ethics awareness (hereinafter referred to as AIEA). This is a study to investigate whether there is a gender difference in the AIEA, and if so, when the gender difference will occur. This study was conducted with 198 elementary school students (98 female students, 100 male students), 265 middle school students (166 female students, 99 male students), and 114 high school students (58 female students and 56 male students) in I Metropolitan City. The results are as follows: First, a gender difference in the AIEA between all boys and girls was confirmed. Second, the gender difference in the AIEA tended to be solidified as the school age increased from elementary school to middle school and high school. Third, female students at all stages of elementary school, junior high school, and high school are not yet very reliable in artificial intelligence, and there is a greater concern about non-discrimination than boys. It turns out that they have a negative position on permission to enter the territory. Fourth, the interaction effects of school age and gender have been identified in ‘stability and reliability,’ and in ‘permit and limit’ categories. Taken together, these results show that an educational strategy that approaches the gender equality perspective of the educational program is necessary so that there will be no gender difference in the AIEA during artificial intelligence education activities. 이 연구의 목적은 인공지능 윤리의식에 대한 초등학교, 중학교, 고등학교 학생들의 성차를 분석하는 것이다. 과연 인공지능 윤리의식에 성차가 존재하는지, 존재한다면 언제부터 성차가 발생하는지를 알아보기 위한 연구이다. 본 연구는 I 광역시 초등학생 198명(여학생 98명, 남학생 100명), 중학생 265명(여학생 166명, 남학생 99명), 고등학생 114명(여학생 58명, 남학생 56명)을 대상으로 실시하였다. 본 연구 결과는 다음과 같다. 첫째, 전체 남학생과 여학생 사이의 인공지능 윤리의식의 성차가 확인되었다. 둘째, 인공지능 윤리의식의 성차는 초등학교에서 중학교, 고등학교로 학령이 높아질수록 확고해지는 경향이 있었다. 셋째, 초등학생, 중학생, 고등학생 모든 단계에서 여학생은 아직 인공지능에 대한 신뢰성이 그리 높지 않고, 차별 금지에 대한 우려가 남학생에 비해 크며, 예술 등의 분야에서 인공지능의 인간 영역에의 진입 허용에 대해 부정적인 입장을 가지고 있는 것으로 파악되었다. 넷째, 학령과 성별의 상호 작용 효과는 안정성 및 신뢰성, 그리고 허용과 한계 범주에서 확인되었다. 이러한 결과들을 종합해 볼 때, 인공지능 교육 활동 시 인공지능 윤리의식에 성차가 생기지 않도록 교육 프로그램을 양성 평등적으로 접근하는 교육적 방안이 필요하다고 할 수 있다.

마찰조건에 따른 원통형 강편의 자유단조 해석

정동원,김귀식 濟州大學校 工科大學 産業技術硏究所 1998 尖端技術硏究所論文集 Vol.9 No.2

Finite Element Method is applied to the determination of the deformed bulge profile and strain distribution during upset forming of cylindrical billets. From the results of simulation, The bulging along the z-axis becomes more severe with increasing height reduction and with increasing friction at the die-material interface. The present method can be used for the simple prediction of the deformed shape and strain distribution in upset forging of cylindrical billets with dissimilar frictional conditions at the die-material interface.

Ni-4.5%Al 피복강재의 마모특성

고장권,김성익,오맹종,김귀식 濟州大學校工科大學産業技術硏究所 1997 尖端技術硏究所論文集 Vol.8 No.1

The pin-on-disk type wear testing machine was manufactured using a personal computer, load cell and reduction motor. The tribological properties of Ni-4.5%Al coating steel by flame spray were investigated using this test machine. The experimental result has shown that the wear amount of coating steel was remarkably decreased than the S45C material. In the lubrication environment the wear amount was much less. The friction coefficient of S45C and coating material was respectively 0.4, 0.29 in the air, and it has respectively shown 0.18, 0.24 in the lubrication. Increase of load didn't have effect on the change of the friction coefficient at all.

아연피복강재의 부식피로 균열성장특성

현창해,오맹종,현경수,김귀식 濟州大學校工科大學産業技術硏究所 1996 尖端技術硏究所論文集 Vol.7 No.1

Corrosion fatigue crack growth behaviors of Zinc coating steel, SGH41, in 3% NaCl aqueous solution was investigated with a hydraulic fatigue testing machine. A hydraulic fatigue test machine was manufactured using a personal computer, a proportional valve one, a hydraulic system. Corrosion fatigue crack growth rates of SGH41 is reduced than that of the uncoated steel by anti-corrosion effect of zinc. Paris rule, da/dN=C(ΔK)? is applied about the relation between the stress intensity factor range, ΔK, and crack growth rate, da/dN, of both the coated specimen and the uncoated one. Where the slope of the correlation, m, is 2.24 for the coated specimen and 3.66 for the uncoated one. The corrosion sensitivity, (da/dN)corr/(da/dN)air, of the coated specimen was smaller than that of the uncoated specimen.

아연피복강재의 부식피로 균열성장특성

김귀식,현창해,현경수,오맹종 濟州大學校 産業技術硏究所 1996 산업기술연구소논문집 Vol.7 No.1

Corrosion fatigue crack growth behaviors of Zinc coating steel, SGH41, in 3% NaCl aqueous solution was investiged with a hydraulic fatigue testing machine. A hydraulic fatigue test machine was manufactured using a personal computer, a proportional valve one, a hydraulic system. Corrosion fatigue crack growth rates of SGH41 is reduced than that of the uncoated steel by anti-corrosion effect of zinc. Pans rule, da/dN=C(ΔK)^(m) is applied about the relation between the stress intensity factor range, ΔK, and crack growth rate, da/dN, of both the coated specimen and the uncoated one. Where the slope of the correlation, m, is 2.24 for the coated specimen and 3.66 for the uncoated one. The corrosion sensitivity, (da/dN)_(corr)/(da/dN)_(air), of the coated specimen was smaller than that of the uncoated specimen.

비닐하우스 작물용 자동방제 시스템 개발

임종환,강승균,김귀식 濟州大學校工科大學産業技術硏究所 1995 尖端技術硏究所論文集 Vol.6 No.-

An automatic spraying system has been developed that can be applied to the prevention and extermination of damage by blight and harmful insects for crops in a vinyl plastic house. The system consists of three parts; a nozzle carriage, controller, and pumping system. The nozzle carriage moves along a mono-rail equipped above the ground, which conveys lots of nozzles to spry agricultural chemicals over crops. The controller governs the speed and direction of the nozzle carriage as well as the action of the pumping system. In connection with the spraying system, we also suggest the guidelines for designing the pumping system.

Random 진동하중을 받는 구조물용 재료의 피로파괴에 대한 기초적 연구

김귀식,조성배 濟州大學校 工科大學 産業技術硏究所 1990 産業技術硏究報告 Vol.1 No.-

This paper was to investigate a fatigue damage of structural material under service loading. random loading. This examined irregular factors (α) , wave counting methods and equivalent load amplitudes about three random loading waves generated by a personal computer. Results obtained are follows. 1. It is greatly different of counting results between range and rainflow cycle counting methods applied wide band spectrum, but it is similar those applied narrow band one. 2. A Equivalent load amplitude, Leq. is obtained from m. the index of Paris' rule on a constant load amplitude test, and the result of cycle counting. Here. m is larger, Leq is greater. 3. In relation between irregular factor(α) and the cycle count method, when α is near 1.0 Leq calculated by rainflow method is similarly that by range one, but when α is lower than 0.99. the former is large rather than the latter.

플라즈마용사 TiO₂코팅 강재의 음향방출 특성

김귀식,박경석,홍용의 제주대학교 산업기술연구소 1999 尖端技術硏究所論文集 Vol.10 No.2

In this paper, adhesiveness of plasma thermal sprayed coating steels is investigated through AE(acoustic emission) in loading a tensile. AE parameters used are event, count, energy and peak amplitude. The powders used for the coating are nickel aluminum composite powder Ni-4.5wt.%Al (BOND ) and titanium dioxide powder TiO2 (TOP). Test specimens are BOND, TOP and BT(BOND + TOP) that are sprayed on carbon steel(S45C) by plasma thermal spray. In the tensile testing, the process and occurrence of the exfoliation of the sprayed coating layer can be estimated by AE. Characteristics of AE parameters, such as event, count, amplitude and energy, on the layer exfoliation have all the similar aspects. The exfoliation of BOND specimen occurs from 16% tensile strain to fracture point, TOP specimen does from 1% to 5%, and BT specimen does from 6% to 11%.