• 한국전기전자재료학회논문지
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• 제32권3호
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• pp.223-228
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• 2019

We fabricated a printed Ag:CNT film as a liquid sensor for the detection of HNS (hazardous and noxious substances) in seawater. The paste required for printing was prepared using Ag powder, MWCNTs (multi-walled carbon nanotubes), and an organic binder. The heat treatment process for binder removal was optimized. In order to confirm that the sensor was operational, the resistance change characteristics in brine (3.5%) and methanol (99.8%) were assessed at $20^{\circ}C$. EDL (electrical double layer) formation and redox reactivity were confirmed as the most important reactions affect each electrical property of sensor in brine and methanol. From these results, it was determined that printed Ag:CNT film can be applied as a sensor to detect HNS in seawater.

• Composites Research
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• 제35권2호
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• pp.86-92
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• 2022

본 연구에서는 접착제를 구성하는 분자 결합 구조의 차이가 열가소성 복합재의 계면 특성에 미치는 영향을 판단하기 위해 진행되었다. 고온 오븐 접합 공정을 이용하여 carbonfiber/polyetherketoneketone(CF/PEKK) 열가소성 복합재료를 융합 접합, polyetheretherketone(PEEK), polyetherimide(PEI) 접착제 접합하였다. 그리고 lap 전단 강도 시험과 디지털 광학 현미경과 주사 전자 현미경을 이용한 파단면 분석, FTIR 분석을 수행하였다. 그 결과, 접착제 접합은 CF/PEKK와 접착제를 구성하는 주요 결합기인 에테르기, 케톤기, 이미드기의 결합이 증가한 인터페이즈를 형성하여 접착 강도를 강화시켰다. 그리고, 에테르기와 케톤기를 더 많이 함유한 PEEK를 사용하는 것이 더 강한 결합력을 갖는 인터페이즈를 형성하여, 복합재의 접착 강도를 향상시켰다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.2278-2282
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• 2010

The regulation involved with railway vehicles is defined by law to protect customer and fundamental safety. The persisting period of domestic railway vehicles in general are 25~30years. Expired railway vehicles are disused in various way. The railway vehicles are consists of recyclable various materials, but there is no standardization or calculating method related with railway vehicles to make disuse scenario. In this study, performed to get a recycling ratio about major materials of domestic subway railway vehicles using ISO 22628 which is Road vehicles-Recyclability and recoverrability method. This research provide foundation for further researches, standardization of EoL stage and recycling railway vehicle.

• International Journal of Advanced Culture Technology
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• 제10권1호
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• pp.42-46
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• 2022

To cultivate talented people with creative and convergent thinking skills to live in the era of the 4th industrial revolution, the national curriculum of Korea is gradually emphasizing convergence education and software education. To meet the demands of the times, this paper suggests subject-convergent teaching-learning materials for educating core principles of Support Vector Machines, especially targeting elementary learners. Based on analysis of the national curriculum, achievement standards of three subjects are integrated. After printable worksheets for traditional face-to-face classes had developed, they were transformed to online interactive worksheets for non-face-to-face classes. The teaching-learning materials are expected to promote the growth of the learners' academic motivation and knowledge.

• 한국압력기기공학회 논문집
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• 제13권1호
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• pp.75-83
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• 2017

This study investigated deformation behavior of major nuclear structural materials under cyclic loading conditions via cyclic stress-strain test. The cyclic stress-strain tests were conducted on SA312 TP316 stainless steel and SA508 Gr.3 Cl.1 low-alloy steel, which are used as materials for primary piping and reactor pressure vessel nozzle respectively, under cyclic load with constant strain amplitude and constant load amplitude at room temperature (RT) and $316^{\circ}C$. From the results of tests, the cyclic hardening and softening behavior, stabilized cyclic stress-strain behavior, and ratcheting behavior of both materials were investigated at both RT and $316^{\circ}C$. In addition, appropriate considerations for cyclic deformation behavior in the structural integrity evaluation of major nuclear components under excessive seismic condition were discussed.

• 한국표면공학회지
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• 제45권5호
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• pp.206-211
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• 2012

Process analysis was carried out during deposition of MgO by inductively coupled plasma assisted reactive magnetron sputtering in Ar and $O_2$ ambient. At the initiation of Mg sputtering with bipolar pulsed dc power in Ar ambient, total pressure showed sharp increase and then slow fall. To analyse partial pressure change, QMS was used in downstream region, where the total pressure was maintained as low as $10^{-5}$ Torr during plasma processing, good for ion source and quadrupole operation. At base pressure, the major impurity was $H_2O$ and the second major impurity was $CO/N_2$ about 10%. During sputtering of Mg in Ar, $H_2$ soared up to 10.7% of Ar and remained as the major impurity during all the later process time. When $O_2$ was mixed with Ar, the partial pressure of Ar decreased in proportion to $O_2$ flow rate and that of $H_2$ dropped down to 2%. It was understood as Mg target surface was oxidized to stop $H_2$ emission by Ar ion sputtering. With ICP turned on, the major impurity $H_2$ was converted into $H_2O$ consuming $O_2$ and C was also oxidized to evolve CO and $CO_2$.

• 한국식생활문화학회지
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• 제25권5호
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• pp.607-614
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• 2010

Changes in major volatile odor components (VOC) and sensory properties of kimchi during ripening for 4 days were investigated, and major VOCs of the raw materials of kimchi were also analyzed. Seven of eight major VOCs of kimchi originated mainly from garlic, while one originated from ginger. During 4 days of kimchi ripening, the amount of ethanol, which was substantially higher than that of other VOCs, increased continuously but decreased slightly on the fourth day. The amount of diallyl disulfide decreased during ripening, while that of allyl mercaptan decreased on the first day and increased slightly thereafter. The amount of methyl allyl sulfide, diallyl sulfide, and methyl trisulfide increased continuously during ripening, while that of dimethyl disulfide and methyl propyl disulfide increased until the second day and decreased thereafter. Scores of overall acceptability, taste, and odor for kimchi ripened for 2 days were significantly higher than those of other samples (p<0.05). The correlation between scores of overall acceptability and the amount of dimethyl disulfide or methyl propyl disulfide was higher than that of other VOCs.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1991년도 가을 학술발표회 논문집
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• pp.146-151
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• 1991

In recent years a reasonable supply and demand plan of construction materials which is based upon an accurate forecast has been greatly required to prevent construction works from delaying and slapdash. To meet an above requirement, a short-term forecasting system of construction materials, in this paper, is established, which is approached in engineering aspect and emerged from conventional forecasting systems. The major considerations in setting up this system are the distributed lag of consrection business indicators and seasonal variations in consumption of constuction materials.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.83-84
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• 2018

3D printing technology can be applied to various industries, and is trapped by major technologies that change existing manufacturing processes. 3D printing materials must satisfy designability, economy and productivity, and building materials are required to have strength and economy secured technology. 3D printing technology of construction field can be divided into structural materials and internal and external materials, and is mainly done by extruding and adapting. Particularly when it is applied as an exterior materials, it is mainly applied to an unstructured exterior materials and high accuracy is required. The exterior materials can be used as a cement composite materials, it is suitable also for a lamination type, and the role of a cement base bonding material is important. In this research, we developed a cementitious base binder applicable as a 3D printing exterior materials, confirmed density and strength characteristics for application as an exterior materials, a flame retardancy test for improving the fire resistance of buildings and confirmed its possibility.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.116-117
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• 2019

3D printing technology can be applied to various industries, and is trapped by major technologies that change existing manufacturing processes. 3D printing materials must satisfy designability, economy and productivity, and building materials are required to have strength and economy secured technology. 3D printing technology of construction field can be divided into structural materials and internal and external materials, and is mainly done by extruding and adapting. Particularly when it is applied as an exterior materials, it is mainly applied to an unstructured exterior materials and high accuracy is required. The exterior materials can be used as a cement composite materials, it is suitable also for a lamination type, and the role of a cement base composite material is important. In this research, we developed a cementitious base binder applicable as a 3D printing exterior materials, confirmed high temperature strength characteristics for application as an exterior materials of buildings and confirmed its possibility.