• Elastomers and Composites
• /
• 제54권3호
• /
• pp.232-240
• /
• 2019

A superabsorbent hydrogel (SAH) can absorb and retain water weighing more than a hundred times of their dry weight because of their three-dimensional hydrophilic structure. To fabricate an SAH, itaconic acid (IA) and vinyl sulfonic acid (VSA) were subjected to radical polymerization in an aqueous solution, wherein IA and VSA were neutralized, and then, a crosslinker and a thermal initiator were added in sequence. The structure of poly(IA-co-VSA) was characterized using attenuated total reflectance Fourier-transform infrared spectroscopy. We also studied the changes in the absorption properties of the SAH composites according to the polymerization temperature, degree of neutralization, type and content of the initiator used, and type and content of the crosslinker used. Thus, we could determine the effects of some synthetic factors on the absorption properties of the SAH.

• Journal of information and communication convergence engineering
• /
• 제20권1호
• /
• pp.65-72
• /
• 2022

With the mark of the fourth industrial revolution, the smart factory is evolving into a new future manufacturing plant. As a human-machine-interactive tool, augmented reality (AR) helps workers acquire the proficiency needed in smart factories. The valuable data displayed on the AR device must be delivered intuitively to users. Current AR applications used in smart factories lack user movement calibration, and visual fiducial markers for position correction are detected only nearby. This paper demonstrates a marker-based object detection using perspective projection to adjust augmented content while maintaining the user's original perspective with displacement. A new angle, location, and scaling values for the AR content can be calculated by comparing equivalent marker positions in two images. Two experiments were conducted to verify the implementation of the algorithm and its practicality in the smart factory. The markers were well-detected in both experiments, and the applicability in smart factories was verified by presenting appropriate displacement values for AR contents according to various movements.

• 한국정보기술학회 영문논문지
• /
• 제9권2호
• /
• pp.41-54
• /
• 2019

The cinema circuit is facing a digital, network, and mobile age, which expands non-theater accessibility to movies. Application platforms are situated as the most competitive business model that provide digital content such as games, music, books, and movies. Consumers can acquire content-related information not just offline, but online as well. Therefore, item information provided by application platforms is required. The information provided by application platforms consists of richly descriptive information such as storyline summary, consumer reviews, and related articles, while non-descriptive normative information covers data such as sales ranking, release date, genre, rental or purchase cost, domestic/foreign classification, consumer rating, number of consumer ratings, film rating, and so on. In this study, we surveyed and analyzed statistically the correlation between real-time sales ranking and other comparable non-descriptive information.

• 한국재료학회지
• /
• 제30권4호
• /
• pp.184-196
• /
• 2020

In this study, effects of carbon and nickel on microstructure and low temperature Charpy impact properties of HSLA (high strength low alloy) steels are investigated. To understand the complex phase transformation behavior of HSLA steels with high strength and toughness before and after welding processes, three kinds of HSLA steels are fabricated by varying the carbon and nickel content. Microstructure analysis, low temperature Charpy impact test, and Vickers hardness test are performed for the base metals and CGHAZ (coarse-grain heat affected zone) specimens. The specimens with the lowest carbon and nickel content have the highest volume fraction of AF, the lowest volume fraction of GB, and the smallest GB packet size. So, the low temperature Charpy absorbed energy of the CGHAZ specimen is the highest. The specimens with increased carbon and nickel content have the lowest volume fraction of AF, the highest volume fraction of GB, and the largest GB packet size. So, the low temperature Charpy absorbed energy of the CGHAZ specimen is the lowest.

• 한국식품저장유통학회지
• /
• 제19권5호
• /
• pp.652-658
• /
• 2012

수확시기에 따른 제주산 가공용 감귤의 이화학적 특성과 hesperidin함량을 검토하였다. 수확시기가 늦어짐에 따라 가용성 고형물의 함량이 증가되는 경향을 보였으며, 당산비도 증가하는 경향을 보였다. 이는 pH의 변화와 비슷한 경향을 보였다. 그러나, 적정산도는 약간 감소하는 경향을 보였다. 색도를 측정한 결과, L, b값과 탁도는 수확시기가 늦어질수록 약간 감소하는 경향을 보였으나, a값은 수확시기가 늦어질수록 약간 증가하는 경향을 보였다. 백탁현상의 주요원인이 되는 hesperidin함량은 수확시기가 늦어짐에 따라 감소하는 경향을 보였다. 이는 빠르게 수확한 과즙을 이용하여 가공품을 제조 시 혼탁이 적을 것으로 예상된다.

• 한국분말재료학회지
• /
• 제27권4호
• /
• pp.311-317
• /
• 2020

In this study, the effects of Co content on the microstructure and Charpy impact properties of Fe-Cr-W ferritic/martensitic oxide dispersion strengthened (F/M ODS) steels are investigated. F/M ODS steels with 0-5 wt% Co are fabricated by mechanical alloying, followed by hot isostatic pressing, hot-rolling, and normalizing/tempering heat treatment. All the steels commonly exhibit two-phase microstructures consisting of ferrite and tempered martensite. The volume fraction of ferrite increases with the increase in the Co content, since the Co element considerably lowers the hardenability of the F/M ODS steel. Despite the lowest volume fraction of tempered martensite, the F/M ODS steel with 5 wt% Co shows the highest micro-Vickers hardness, owing to the solid solution-hardening effect of the alloyed Co. The high hardness of the steel improves the resistance to fracture initiation, thereby resulting in the enhanced fracture initiation energy in a Charpy impact test at - 40℃. Furthermore, the addition of Co suppresses the formation of coarse oxide inclusions in the F/M ODS steel, while simultaneously providing a high resistance to fracture propagation. Owing to these combined effects of Co, the Charpy impact energy of the F/M ODS steel increases gradually with the increase in the Co content.

• 융합정보논문지
• /
• 제10권9호
• /
• pp.251-261
• /
• 2020

본 연구의 목적은 전 세계적인 한류의 열풍으로 K-beauty의 관심이 높아지고, 뷰티산업 종사자들도 유튜브 헤어미용 콘텐츠를 시청하며 최신 트랜드를 교류하고 있어 유튜브 콘텐츠의 이용동기와 신뢰도, 만족도, 지속이용의도의 관계를 살펴 보고, 향후 뷰티 종사자의 콘텐츠 소비 또는 제작 시 필요한 시사점을 제시하기 위함이다. 분석방법은 빈도분석, 요인분석, 신뢰도분석, 상관관계분석, 다중회귀분석 등을 하였고, 그 결과 콘텐츠 이용동기, 신뢰도, 만족도, 지속이용의도 간 상호 정(+)의 상관관계가 나타났고, 콘텐츠 이용동기가 유튜브 콘텐츠 만족도, 지속이용의도에 통계적 유의하게 정(+)의 영향이 나타났으며, 콘텐츠 신뢰도가 유튜브 콘텐츠 만족도와 지속이용의도에 통계적 유의하게 정(+)의 영향을 나타나는 것을 알 수 있었다. 따라서 콘텐츠에 대한 질적 향상을 통해 차별화 된 유튜브 콘텐츠 개발 및 제작으로 뷰티산업 발전에 기여할 수 있는 계기가 되길 바란다.

• 공업화학
• /
• 제25권5호
• /
• pp.463-467
• /
• 2014

본 연구에서는 팽창흑연의 함량 변화를 달리하여 제조한 팽창흑연/에리스리톨 복합체의 열적거동에 관하여 고찰하였다. 팽창흑연이 도입된 팽창흑연/에리스리톨 복합체의 표면 및 구조특성은 scanning electron microscope (SEM), transmission electron microscope (TEM), 그리고 X-ray diffraction (XRD)를 이용하여 관찰하였으며, 열적특성은 differential scanning calorimetry (DSC)와 thermal conductivity (TC)를 이용하여 분석하였다. 실험 결과 팽창흑연의 함량이 증가함에 따라 팽창흑연/에리스리톨 복합체의 열전도도가 증가하였으며, 반면에 잠열은 팽창흑연의 존재 하에 약간 감소하였다. 결론적으로 팽창흑연은 상변이 물질의 높은 열 전달성능 및 열 저장능력을 향상시키는데 적합한 소재라 판단된다.

• The Plant Pathology Journal
• /
• 제33권3호
• /
• pp.264-275
• /
• 2017

The spent mushroom substrate (SMS) of Lentinula edodes that was derived from sawdust bag cultivation was used as materials for controlling Phytophthora blight disease of pepper. Water extract from SMS (WESMS) of L. edodes inhibited mycelial growth of Phytophthora capsici, suppressed Phytophthora blight disease of pepper seedlings by 65% and promoted growth of the plant over 30%. In high performance liquid chromatography (HPLC) analysis, oxalic acid was detected as the main organic acid compound in WESMS and inhibited the fungal mycelium at a minimum concentration of 200 mg/l. In quantitative real-time PCR, the transcriptional expression of CaBPR1 (PR protein 1), CaBGLU (${\beta}$-1,3-glucanase), CaPR-4 (PR protein 4), and CaPR-10 (PR protein 10) were significantly enhanced on WESMS and DL-${\beta}$-aminobutyric acid (BABA) treated pepper leaves. In addition, the salicylic acid content was also increased 4 to 6 folds in the WESMS and BABA treated pepper leaves compared to water treated leaf sample. These findings suggest that WESMS of L. edodes suppress Phytophthora blight disease of pepper through multiple effects including antifungal activity, plant growth promotion, and defense gene induction.

• 멤브레인
• /
• 제31권6호
• /
• pp.456-470
• /
• 2021

본 연구에서는 비용매 유도 상분리법을 이용하여 폴리에테르이미드 계열의 중공사형 분리막을 제조하였다. 제조된 중공사막의 모폴로지 조절을 위해 첨가제로는 THF, Ethanol, LiNO₃를 사용하였다. 또한 높은 수소분리막의 개발을 위해 모폴로지와 기체투과성능을 특성평가를 통해 방사조건을 최적화하였다. 그 결과 THF의 함량이 증가할수록 수소/이산화탄소 선택도가 증가하였다. 하지만 trade-off 관계로 인하여 투과율은 감소하였다. Ethanol을 첨가하였을 때는 finger-like 구조를 나타냈고, LINO₃를 첨가하였을 때 Sponge 구조를 보였다. 특히, PDMS 코팅층을 최적화한 중공사막의 경우, 투과율은 40 GPU, 수소/이산화탄소 선택도는 5.6을 나타냈다.