• Corrosion Science and Technology
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• 제15권6호
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• pp.297-302
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• 2016

Water-based systems are dominating the coating market because of worldwide VOCs regulations. Research is focusing especially on waterborne polyurethane (WPU) because of its unique mechanical and chemical properties. However, commercial WPU consists of linear thermoplastic polymers with polar groups on the main chain, which do not perform as well as solvent-borne PU in a two-pack system. In this study, APTES were used as a chain crosslink agent to overcome commercial WPU's limited performance. WPUs synthesized by using a sol-gel process were evaluated with FT-IR, particle analysis, TGA, tensile tests, pull-off tests, SEM, and EIS. The results showed that WPUs with added APTES had better thermal stability, mechanical properties, and water resistance than did WPUs without added APTES. Consequently, the sol-gel process increased the crosslink density of WPUs and modified the WPU's own properties.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.127-128
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• 2021

Rigid urethane foam is widely applied because it is light and has superior insulation performance compared to insulation materials such as EPS or glass wool. However, it has the disadvantage of being vulnerable to fire. Therefore, in this study, before proceeding with the research to improve the fire resistance of the rigid polyurethane foam, we would like to investigate the change in density and thermal conductivity of the rigid polyurethane foam according to the change in the mixed weight of the main material and the curing agent. It was found that the density increased as the mixed weight increased. The thermal conductivity showed similar values overall. As for the density distribution, the central part was low and the outer part was high.

• Journal of Ginseng Research
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• 제36권1호
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• pp.1-15
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• 2012

The major commercial ginsengs are Panax ginseng Meyer (Korean ginseng), P. quinquifolium L. (American ginseng), and P. notoginseng (Burk.) FH Chen (Notoginseng). P. ginseng is the most commonly used as an adaptogenic agent and has been shown to enhance physical performance, promote vitality, increase resistance to stress and aging, and have immunomodulatory activity. These ginsengs contain saponins, which can be classified as dammarane-type, ocotillol-type and oleanane-type oligoglycosides, and polysaccharides as main constituents. Dammarane ginsenosides are transformed into compounds such as the ginsenosides $Rg_3$, $Rg_5$, and $Rk_1$ by steaming and heating and are metabolized into metabolites such as compound K, ginsenoside $Rh_1$, proto- and panaxatriol by intestinal microflora. These metabolites are nonpolar, pharmacologically active and easily absorbed from the gastrointestinal tract. However, the activities metabolizing these constituents into bioactive compounds differ significantly among individuals because all individuals possess characteristic indigenous strains of intestinal bacteria. To overcome this difference, ginsengs fermented with enzymes or microbes have been developed.

• Journal of Positioning, Navigation, and Timing
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• 제10권2호
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• pp.113-120
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• 2021

The Distance Measuring Equipment (DME) is a ground-based aircraft navigation system and is considered as an infrastructure that ensures resilient aircraft navigation capability during the event of a Global Navigation Satellite System (GNSS) outage. The main problem of DME as a GNSS back up is a poor positioning accuracy that often reaches over 100 m. In this paper, a novel approach of applying deep reinforcement learning to a DME pulse design is introduced to improve the DME distance measuring accuracy. This method is designed to develop multipath-resistant DME pulses that comply with current DME specifications. In the research, a Markov Decision Process (MDP) for DME pulse design is set using pulse shape requirements and a timing error. Based on the designed MDP, we created an Environment called PulseEnv, which allows the agent representing a DME pulse shape to explore continuous space using the Soft Actor Critical (SAC) reinforcement learning algorithm.

• 한국건축시공학회지
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• 제12권6호
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• pp.566-574
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• 2012

To address the problem of global warming, consumption of cement, the main material of concrete, should be decreased. Unfortunately, when industrial by-products are used in large quantities as admixture, the early age strength of concrete will be decreased, reducing its viability for use in concrete structures. Therefore, in this study, the application of an ionization accelerator and alkaline activator as addition agent of superplasticizer were investigated to secure a similar early age strength to that of normal concrete, thus increasing the viability of low cement concrete. Through the investigation, it was found that specimens that used a combination of Alkaline-activator (Na2Sio3) and ionization accelerator (Amine) had the highest early and long-age compressive strength. From this, we can determine an appropriate range of application of superplasticizer to improve early-age compressive strength of low cement concrete.

• 한국군사과학기술학회지
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• 제17권1호
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• pp.122-128
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• 2014

Remote fourier transform infrared(FTIR) chemical imaging detection system allows detection and identification of gases in the atmosphere from long distances. In this paper, the appropriate field of view(FOV) of the FTIR imaging system was examined and the main performance of the system for the interferometer was described. For the determination of the FOV, simulations of gas dispersion range were performed with the NBC reporting and modeling software(NBC-RAMS) developed by ADD. As a result, minimum 192 mrad of FOV was required for the remote FTIR imaging system to visualize chemical warfare agents dispersed in several hundred meters. At the same time, 0.75 mrad of instantaneous field of view(IFOV) for a linear interferometer proper to take a FOV for the chemical agent imaging.

• 한국환경과학회지
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• 제32권10호
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• pp.741-744
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• 2023

This study focused on high school laboratory research and the main purpose was to develop alternative additives for livestock waste and ammonia volatilization methods with high school students as participants and to provide information to business owners based on the results. Compared to the control groups, The bentonite and illite treatment groups had similar ammonia volatilization, pH, EC, and total nitrogen content. In particular, the alum and aluminum chloride mixed treatment group showed low pH and ammonia volatilization, and high EC and total nitrogen content for poultry litter. As a result, when focusing on high school laboratory research, the alum and aluminum chloride mixed agent treatment fulfilled its role as an alternative additive for ammonia reduction. In addition, this approach can be suggested as a method to solve difficulties in adapting to the field through a practical cooperative relationship with livestock farms.

• 감성과학
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• 제21권1호
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• pp.59-70
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• 2018

음성인식 기술의 비약적 발전으로 최근 몇 년 사이 대화형 에이전트는 스마트폰, 인공지능 스피커 등을 통해 널리 보급되었다. 음성인식 기술의 인식의 정확도는 인간의 수준까지 발전하였으나, 여전히 말의 의미나 의도를 파악하는 것과 긴 대화를 이해하는 것 등에는 한계를 보이고 있다. 이에 따라 사용자는 대화형 에이전트를 사용함에 있어 다양한 오류 상황들을 경험하고 있으며 이는 사용자 경험에 부정적인 영향을 미칠 수 있다. 또한, 목소리를 주 인터페이스로 하는 인공지능 스피커의 경우, 대화형 에이전트의 기능 및 한계에 대한 피드백의 부족은 지속적 사용을 저해하는 요소로 꼽히고 있다. 따라서 사용자가 대화형 에이전트의 기능 및 한계를 보다 잘 이해하고 오류 상황에서 부정적인 감정을 완화할 수 있는 방안에 대한 연구에 대한 필요성이 높으나, 아직 관련 연구는 미비한 실정이다. 이에 본 연구에서는 사회적 전략 중 '사전 양해'와 '사과'를 대화형 에이전트에 적용하고 이러한 전략이 사용자가 에이전트에 대해 느끼는 인식에 어떠한 영향을 미치는지 조사하였다. 이를 위해 사전 양해와 사과 여부를 나누어 사용자가 대화형 에이전트와 대화하는 데모 영상을 제작하였고, 실험참가자들에게 영상을 보여준 뒤 느끼는 호감도와 신뢰도를 설문을 통해 평가하도록 하였다. 총 104명의 응답을 분석한 결과, 문헌조사를 토대로 한 우리의 예상과는 상반되는 결과를 얻었다. 사전 양해는 오히려 사용자에게 부정적인 인상을 주었으며, 특히 에이전트에 대한 신뢰도에 부정적인 영향을 주었다. 또한 오류 상황에서의 사과는 사용자가 느끼는 호감도나 신뢰도에는 유의미한 영향을 미치지 않았다. 심층인터뷰를 통해 원인을 파악한 결과, 실험참가자들은 인공지능 스피커를 사람과 같은 인격체보다는 단순한 기계에 가깝다고 인식했기 때문에 인간관계에 작용하는 사회적 전략이 영향력을 발휘하지 못한 것으로 해석된다. 이러한 결과는 사용자가 에이전트를 얼마나 기계, 혹은 사람에 가깝게 인식하는지에 따라 오류 상황에 대한 에이전트의 대처 방식 또한 달라져야 함을 보여준다.

• Journal of Ginseng Research
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• 제35권2호
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• pp.209-218
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• 2011

Ginseng has been used as a general tonic agent to invigorate the human body as an adaptogenic agent. In a previous report, we have shown that ginseng contains a novel glycolipoprotein called gintonin. The main function of gintonin is to transiently enhance intracellular free $Ca^{2+}$ $[Ca^{2+}]_i$ levels in animal cells. The previous method for gintonin isolation included multiple steps using organic solvents. In the present report, we developed a simple method for the preparation of crude gintonin from ginseng root as well as stem and leaf, which produced a higher yield of gintonin than the previous one. The yield of gintonin was 0.20%, 0.29%, and 0.81% from ginseng root, stem, and leaf, respectively. The apparent molecular weight of gintonin isolated from stem and leaf through sodium dodecyl sulfate polyacrylamide gel electrophoresis was almost same as that from root but the compositions of amino acids, carbohydrates or lipids differed slightly between them. We also examined the effects of crude gintonin from ginseng root, stem, and leaf on endogenous $Ca^{2+}$-activated $Cl^-$ channel (CaCC) activity of Xenopus oocytes through mobilization of $[Ca^{2+}]_i$. We found that the order of potency for the activation of CaCC was ginseng root > stem > leaf. The $ED_{50}$ was $1.4{\pm}1.4$, $4.5{\pm}5.9$, and $3.9{\pm}1.1$ mg/mL for root, stem and leaf, respectively. In the present study, we demonstrated for the first time that in addition to ginseng root, ginseng stem and leaf also contain gintonin. Gintonin can be prepared from a simple method with higher yield of gintonin from ginseng root, stem, and leaf. Finally, these results demonstrate the possibility that ginseng stem and leaf could also be utilized for ginstonin preparation after a simple procedure, rather than being discarded.

• 한국자기학회지
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• 제25권3호
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• pp.67-73
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• 2015

본 연구는 철기(Fe based) $Fe_{73.5}Si_{13.5}B_9Nb_3Cu_1$ 나노결정 합금의 분말코어(powder core)의 연자기적 특성 향상을 위한 기초연구로서, 절연 코팅제의 첨가량 및 분말입도에 따른 투자율, 코어손실 및 DC 바이어스 특성을 주로 조사하였다. 우선 합금조성을 PFC 장치를 이용하여 비정질 합금리본을 제조한 후, 열처리, 미분쇄 및 분급하여 얻어진 합금분말에 절연 코팅제(PEI)의 첨가량을 0.5, 1.0, 2.0, 2.5 wt%로 변화시켜 $16ton/cm^2$으로 압축성형 및 결정화 열처리하여 제조한 토로이달 나노결정 분말코어($OD12.7mm{\times}ID7.62mm{\times}H4.75mm$)는 절연 코팅제 함량이 증가할수록 투자율은 감소하였지만, 코어손실 및 DC 바이어스 특성은 향상됨을 확인하였다. 이러한 이유는 합금분말 절연 코팅제 첨가량이 증가할수록 비정질 합금분말 입자가 적어져 분말코어의 성형밀도가 낮아지기 때문으로 추정되었으며, 절연 코팅제의 함량은 1 wt%가 가장 적합한 것으로 판단되었다. 또한 절연 코팅제 함량을 1 wt%로 고정하고, 합금분말의 입도에 따라 제조한 분말코어의 경우, 실효투자율 및 코어손실은 입도가 클수록 우수하였지만, DC 바이어스 특성은 인가자장이 증가함에 따라 더욱 나빠짐을 확인하였다. 그 이유는 합금분말 표면의 코팅층 두께 차이에 의한 절연효과, 잔류기공 혹은 분말코어의 성형밀도 차이 등에 기인하는 것으로 추정되었다.