해양탐지체계 성능향상을 위한 합성고분자 기반 기능성 코팅제 개발

홍순국(Hong, Soon-Kook) 해군사관학교 해양연구소 2019 海洋硏究論叢 Vol.52 No.-

Lignin, which can be easily derived from the wood components, now widely have been studied for anti-bacterial and anti-microbial applications owing to its innate properties, ease flexibility and low cyto-toxicity. For potential applications of lignin-based materials for coating and protective layers of marine detection systems, its physico-chemical and biological properties must be studied. In this research, anti-bacterial and anti-microbial behaviors of both alkali and kraft lignins were studied by measuring the physical properties upon dissolution in organic solvent and investigating the anti-bacterial and anti-microbial characteristics using E. coli as a model system. The optimal concentrations of both alkali and kraft lignins were found to be 2 mg/mL for alkali lignin and 3 mg/mL for kraft lignin. The introduction of both lignins showed 10~30 % cyto-toxicity. Such a coating material can offer novel strategies to achieve the enhanced capability of marine detection system.

저 Pb Sn-5%Pb-1.5%Ag-x%In계 솔도 합금의 특성에 관한 연구

홍순국,주철홍,강정윤,김인배,Hong, Sun-Guk,Ju, Cheol-Hong,Gang, Jeong-Yun,Kim, In-Bae 한국재료학회 1998 한국재료학회지 Vol.8 No.11

Pb의 환경오염 문제를 발생하지 않는 저농도 Pb 솔도합금을 개발하기 위하여, 새로운 Sn-5%Pb-1.5%Ag-x%In계 합금 조성을 설계하고, 이 합금의 융점, 젖음성, 상분석, 경도, 인장강도, 드로스성을 평가하여, Sn-37%Pb 솔더오 대체 가능성을 타진하였다. Sn-37%Pb 솔도 합금의 Pbdldhs 용출농도는 국제규제치인 3ppm보다 훨씬 적은 0.46ppm이었고, 환경문제를 유발하지 않는 것으로 확인되었다. 이 합금계의 융점은 $183-192^{\circ}C$이고, 응고온도범위도 $5^{\circ}C$내외로 매우 좁았다. 젖음성은 In의 첨가양에 따라 큰 차이가 거의 없었으며, Sn-375Pb와 비슷하였다. 융점 및 젖음성 측면에서 Sn-37%Pb와 대체 가능한 것으로 판단되었다. 경도는 Sn-37%Pb의 약 1.5배이고, 인장강도는 Sn-37%Pb의 것보다 높고, In의 첨가량에 따라 증가하였지만, 연신율은 감소하였다. In이 1% 첨가된 합금에서는 수지 상정 경계에 Ag3Sn과 Pb가 정출되고, 3% 이상에서는 $Ag_3Sn$과 $Ag_3In$ 및 Pb가 정출되었다. 드로스 생성속도는 Sn-37%Pb 합금이 Sn-5%Pb-1.5%Ag 합금보다 빠르고, In을 첨가할수록 느리고 2%의 In을 첨가한 합금은 180분에서도 거의 드로스가 발생하지 않았다. This work designed Sn-5%Pb-1.5%Ag-x%In solder alloy to develop the solder alloy with low Pb content. This solder alloy doesn't cause environmental pollution. and this study reviewed the probability of replacement of Sn-37%Pb solder as evaluation of melting range, wettability. microstructure, microhardne'ss, tensile strength, drossability of this new solder alloys. The level of international regulation in dissolution amount of Pb ion was 3ppm. But dissolution amount of Pb ion in Sn-5%Pb solder alloy confirmed not to threat the global environmental is 0.46ppm. The melting range of this solder alloy was $183-192^{\circ}C$. Also the range of solidification was very narrow within $5^{\circ}C$. The wettability was similar to Sn-37%Pb solder, and the effect of amount of In addition of wettability couldn't be founded. The probability of replacement in the melting range and wettability is very high. And microhardness of this solder alloy was 1.5 times of conventional type solder. Tensile strength of new solder alloys was a little high than that of conventional type solder. With increasing amount of In% addition, tensile strength was increased, but elongation was decreased. The solder alloy of l%In addition revealed AgSn and Pb on dendrite microstructure boundary, and $Ag_3Sn$, $Ag_3In$ and Pb were revealed on it at the solder alloy of 3% In addition. The drossability was superior to Sn-37%Pb solder alloy and the solder alloys of 2% In addition was not generated for 3hrs.

극한 환경에서 급속발열과 장기내구성을 가지는 CNT 필름 개발

홍순국(Hong, Soon-Kook) 해군사관학교 해양연구소 2018 海洋硏究論叢 Vol.51 No.-

Carbon nanotube (CNT) composites widely have been studied for resistive heating applications (such as de-icing unit, patternable micro heaters and water heater) owing to their light-weight properties, flexibility and rapid heating. For mass product of CNT composite as resistive heating element applications, the change of electrical resistance with different temperature must be studied. In this research, resistive heating behavior of CNT/Polydimethylsiloxane (PDMS) composite film were studied by measuring the change in electrical resistance under temperature from -40 ℃ to 100 ℃. The CNT/PDMS composite film showed 25 % resistance change from -40 ℃ to 100 ℃. The polymer coefficient of thermal expansion (CTE) is an important factor to consider in the design of CNT composites as a heating unit. The CNT/PDMS composite is appropriate for de-icing application and flexible heating element owing to the lower degree of electrical resistance change.

군용 수중 운동물체의 성능강화를 위한 초소수성 나노 패터닝 기술

홍순국(Soon-Kook Hong),이기영(Ki-Young Lee) 한국해양공학회 2013 韓國海洋工學會誌 Vol.27 No.2

A superhydrophobic surface means that the contact angle between the solid surface and a water droplet is more than 150°. Materials with a superhydrophobic surface have a self?cleaning function because of the Lotus effect, in which water is not absorbed by the material but rolls off of it. If such a Lotus effect can be applied to the surface of underwater vessels, submarines, torpedos, and so on, enhanced vessels can be made based on this lubricant effect reducing the friction coefficient for the liquid. Because polymer composites can be easily applied in various nanotechniques, they are more advantageous than conventional materials like iron in terms of a superhydrophobic surface. Furthermore, a superhydrophobic surface bring enhanced anticorrosion and ecotechnology because no paint is needed on underwater vessels.

안정 동위원소비를 이용한 농촌하천유역 질산성 질소의 오염원 추정

홍영진 ( Hong Young Jin ),권순국 ( Kwun Soon Kuk ),홍성구 ( Hong Seong Gu ) 한국농공학회 2001 韓國農工學會誌 : 전원과 자원 Vol.43 No.4

Pollution sources and their environmental contributions were investigated to select the best management practices for the effective control of water quality. The nitrogen isotope mass ratio was determined to estimate the nitrate sources and their contribution Sampling sites were chosen by calculating effluent loads at each watershed. Two liters each of the surface water samples were collected from four sites at Bokha river and two sites at Gwanri river. They were sequentially prepared through distillation method and analyzed using an isotope ratio mass spectrometer(IsoPrime EA). As revealed by the experimental values obtained, the mass ratio values(□ ¹⁵N) of watersheds with a large amount of nonpoint sources were less than +5%, an indication that the samples were influenced by chemical fertilizers. However, watersheds with large amount of point sources were influenced not only by chemical fertilizers but also by animal and municipal wastes. The mass ratio values of samples generally decreased during rainy days. But, during dry days, the mass ratio values well-reflected the nitrate sources the condition of watersheds. Through this study, the nitrogen isotope mass ratio has been found to be useful for estimating nitrate sources and their contribution to the rural watersheds

국내 노인복지관 내 운동프로그램 개선방안에 관한 연구

홍순국(Hong, Soon-Gook),김준홍(Kim, June-Hong),전태원(Jun, Tae-Won) 한국사회체육학회 2016 한국사회체육학회지 Vol.0 No.65

The main purpose of this study is to suggest directions of operating exercise programs for elderly at local senior welfare centers as well as the methods to improve their qualities by analyzing the programs themselves and their participants. We analyzed subjects (n=108) who had taken parts in 17 exercise programs out of 68 social education programs for approximately four months. Participating in these programs at the center resulted in somewhat positive outcomes in the elderly, but these programs did not provide sufficient levels of intensity nor plentiful types of exercises to overcome negative effects of aging. Based on this result with the information provided, we drew a conclusion that it is recommended to have resistance and aerobic exercises in equal portions when establishing these exercise programs. In addition, we recommend that systematic consultations and managements of exercise programs be provided to individuals based on their results from the preliminary examinations performed with scientific methods. Moreover, given limitations in spaces, it is needed for instructors to have assistants or to use visual aids to enhance efficiency of their classes, while providing frequent feedbacks on the level of intensity that is appropriate for each individual and additional information regarding their proper dietary plans.

무인수상정 열습효과로 인한 탄소복합재의 층간전단강도 저하에 관한 연구

홍순국(Soon-Kook Hong) 한국해군과학기술학회 2022 Journal of the KNST Vol.5 No.2

농촌하천 유역의 주 오염원 추적을 위한 안정성 동위원소 질량비 분석

홍영진 ( Hong Young Jin ),김철성 ( Kim Chul Sung ),권순국 ( Kwun Soon Kuk ) 한국농공학회 1999 한국농공학회 학술대회초록집 Vol.1999 No.-

It has been acknowledged that fertilizer and animal waste have different ratio of ¹⁵N/¹⁴N which is presented as a symbol of δ ¹⁵N, and that the values of δ ¹⁵N for fertilizer and animal waste are placed less than +8%₀ and higher than +10%₀, respectively. By this reason, the demarcation range for the source nitrogen mass ratio is between +8 %₀ and + 10 %₀. In this study, we would suggest a possible method to trace the major pollution basis using 'the nitrogen isotope analysis method for management of water quality.

농촌유역의 질소 오염원과 기여도 해석을 위한 δ ¹⁵N 분석

홍영진 ( Hong Young Jin ),권순국 ( Kwun Soon Kuk ) 한국농공학회 2000 한국농공학회 학술대회초록집 Vol.2000 No.-

It has been acknowledged that fertilizer, natural soil nitrogen and animal waste, municipal waste have different mass ratio of nitrogen which is presented as a symbol of δ ¹⁵N. and that the values of δ ¹⁵N for fertilizer and natural soil nitrogen and animal waste are placed less than +5‰ and higher than +10‰, respectively. thus, Nitrogen pollution sources and contribution can be interpreted in watershed through δ ¹⁵N analysis and then, analysis is performed with Kjeldhl-Dumas method. In this study, The values of δ ¹⁵N are between +1.46‰ and +8.97‰, and the nitrate concentration is placed less than 3.31mg/L and higher than 0.19mg/L, respectively. Thus, this watershed is noncontamination area at the present time. But as a result of δ ¹⁵N, contribution of natural soil nitrogen be discovered in this watershed, presently.

신증후출혈열에 대한 임상적 관찰

홍순국,Hong, Soon-Kuk 한국생명보험의학회 1987 保險醫學會誌 Vol.4 No.1