• 한국전기전자재료학회논문지
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• 제35권4호
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• pp.311-321
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• 2022

The report reviews recent research efforts in demonstrating a computing system whose operation principle mimics the dynamics of biological neurons. The temporal variation of the membrane potential of neurons is one of the key features that contribute to the information processing in the brain. We first summarize the neuron models that explain the experimentally observed change in the membrane potential. The function of ion channels is briefly introduced to understand such change from the molecular viewpoint. Dedicated circuits that can simulate the neuronal dynamics have been developed to reproduce the charging and discharging dynamics of neurons depending on the input ionic current from presynaptic neurons. Key elements include volatile memristors that can undergo volatile resistance switching depending on the voltage bias. This behavior called the threshold switching has been utilized to reproduce the spikes observed in the biological neurons. Various types of threshold switch have been applied in a different configuration in the hardware demonstration of neurons. Recent studies revealed that the memristor-based circuits could provide energy and space efficient options for the demonstration of neurons using the innate physical properties of materials compared to the options demonstrated with the conventional complementary metal-oxide-semiconductors (CMOS).

• The Korean Journal of Ecology
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• 제28권3호
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• pp.135-139
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• 2005

서양등골나물의 휘발성 추출물에 포함된 terpenoid 화합물을 분리, 동정하였고, 주요 물질 4종에 대한 종자발아와 유식물 생장을 조사하였다. 서양등골나물 정유에 포함된 화합물의 수는 $\beta$-caryophyllene, $\alpha$-terpinenol, chamazulene, bornyl acetate, $\alpha$-pinene등 총 49종이었으며, 그 중 3종은 미확인되었다. 서양등골나물의 정유로부터 분리 확인한 휘발성 화학물질 중 다량 함유되어 있거나 중요한 성분으로 판명된 $\alpha$-pinene, bornyl acetate, linalool 및 terpinen-4-ol 등 4종의 물질에 대한 녹두의 발아 억제 효과를 조사하였다. linalool과 terpinen-4-ol에 의해서는 녹두의 종자가 전혀 발아하지 못하여 발아 억제효과가 매우 큰 것으로 보인다. 정유 내 화합물에 의한 녹두 유식물의 초기 생장 결과, $\alpha$-pinene과 bornyl acetate에 대한 묘조와 유근의 생장은 농도에 따라 점점 억제되었고, linalool과 terpinen-4-ol에 대해서는 실험구에서 생장 반응이 나타나지 않을 만큼 강하게 억제반응이 나타났다. 생체량에 있어서 $\alpha$-pinene의 경우 58 ${\mu}l$ 이상에서 유의한 영향을 미치고 있었으며, bornyl acetate의 경우에는 19 ${\mu}l$ 이상에서 감소하는 것으로 나타났으나 그 이후에는 통계적으로 유의한 차이를 나타내지는 않았다. 위의 결과를 종합해 볼 때, 정유 내에 포함된 서양등골나물의 알레로 화합물 중 생물검정에 사용된 $\alpha$-pinene, bornyl acetate, linalool과 terpinen-4-ol은 식물의 발아 억제 효과를 나타내는 주요한 물질 중 하나로 생각되며, 특히 linalool과 terpinen-4-ol은 다른 식물의 생장을 감소시키는 데 탁월한 효과가 있음을 알 수 있었다.

• 농업과학연구
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• 제38권4호
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• pp.723-730
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• 2011

To search for the new development of industrial application of woody plants, the chemical composition of the volatile constituents from woody plants (Evodia daniellii, Clerodendron trichotomum, Prunus padus, and Zanthoxylum ailanthoides) was determined by GC and GC/MS spectrometric analysis with the aid of NBS, Wiley Library and RI indice searches. The major constituents were t-ocimene from the leaves of E. daniellii, linalool from the leaves of C. trichotomum, benzaldehyde from the leaves and twigs of P. padus, ${\beta}$-thujene from the leaves of Z. ailanthoides, and 2-undecanone from the stems of Z. ailanthoides. These results suggested that the major volatile constituents of woody plants could be a useful lead compound in the development of functional materials for industrial application.

• Journal of the Optical Society of Korea
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• 제18권4호
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• pp.301-306
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• 2014

A porous silicon microcavity (PSMC) sensor has been made for vapors of solvent solutions, and a method has been developed in order to obtain simultaneous determination of two volatile substances with different concentrations. In our work, the temperature of the solution and the velocity of the air stream flowing through the solution have been used to control the response of the sensor for ethanol and acetone solutions. We study the dependence of the cavity-resonant wavelength shift on solvent concentration, velocity of the airflow and solution temperature. The wavelength shift depends linearly on concentration and increases with solution temperature and velocity of the airflow. The dependence of the wavelength shift on the solution temperature in the measurement contains properties of the temperature dependence of the solvent vapor pressure, which characterizes each solvent. As a result, the dependence of the wavelength shift on the solution temperature discriminates between solutions of ethanol and acetone with different concentrations. This suggests a possibility for the simultaneous determination of the volatile substances and their concentrations.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.117-121
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• 2001

The present study has been conflicted to verify the applicability of tire powder and food waste compost as biofilter materials to degrade volatile organic compounds. Batch and column tests were performed to determine the optimum ratio of tire powder to compost and the appropriate mixing type of two materials for removal of the selected VOCs, i.e., benzene, ethylbenzene, PCE, and TCE. According to batch tests, tire powder and compost mixture had faster removal rate than the compost. The biofilter column filled with tire powder and compost showed better VOC removal efficiency than that filled with only tire powder. In this study, the best removal rate was observed in the sandwich type column test of which the tire : compost weight ratio was 1:2

• 설비공학논문집
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• 제18권3호
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• pp.262-269
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• 2006

Formaldehyde and total volatile organic compounds (TVOC) from building materials have been known as main causes of IAQ problem in Newly-Constructed Multi-Family Houses. Because Multi-Family Houses are built in large quantities in a similar manner, inappropriate selection of building materials and method will detrimental affect IAQ. This research aims to identify major causes of Indoor Air Pollutants in Multi-Family Houses, by constructing Mock-Up & One-Room House. As a result, self leveling concrete, door, and furniture construction is a major cause of indoor formaldehyde increase, and tile bond is TVOC, and urethane water proof is Etylbenzene, and Xylene.

• 기계와재료
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• 제10권3호통권37호
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• pp.78-86
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• 1998

• 월간포장계
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• 통권332호
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• pp.77-93
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• 2020

• Bulletin of the Korean Chemical Society
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• 제34권7호
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• pp.2105-2110
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• 2013

Carbon-fiber-supported NiO catalytic filters for oxidation of volatile organic compounds were prepared by electroless Ni-P plating and subsequent annealing processes. Surface structure and crystallinity of NiO film on carbon fiber could be modified by post-annealing at different temperatures (500 and $650^{\circ}C$). Catalytic thermal decompositions of toluene over these catalytic filters were investigated. $500^{\circ}C$-annealed sample showed a higher catalytic reactivity toward toluene decomposition than $650^{\circ}C$-annealed one under same conditions, despite of its lower surface area and toluene adsorption capacity. X-ray diffraction and X-ray photoelectron spectroscopy studies suggest that amorphous structures of NiO on $500^{\circ}C$-annealed catalyst caused the higher reactivity for oxidation of toluene than that of $650^{\circ}C$-annealed sample with a higher crystallinity.

• 한국가구학회지
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• 제26권1호
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• pp.22-30
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• 2015

In order to prevent decay, distortion, bending, twist on wood products such as wooden furnitures, variety of coating materials were developed and used so far. The coating materials for wood finishing can be synthesized by natural resource or petroleum. However, these coating materials can cause contamination of indoor air quality due to emission of volatile organic compounds (VOCs). In this study, commercialized coating materials for wood finishing such as varnish, coat, and stain were evaluated on emission characteristics of VOCs. Among the varnish, eco-friendly products had about 15~46% lower TVOC emission ($1,042{\mu}g/m^2h{\sim}3,257{\mu}g/m^2h$, respectively, than typical product ($7,100{\mu}g/m^2h$). Natural resource based coating material showed lowest TVOC emission level. However, one of natural resource based waterborne stain showed higher TVOC emission level because waterborne stain already contained higher amount of natural VOC. Oil-based stain might not be suitable for indoor use on interior wall and furniture due to exceed amount of TVOC. Based on results, natural resource based coat or waterborne stain are recommenced to use on wood products.