• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.3
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• pp.187-192
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• 2017

This paper presents an ongoing study to develop a novel pressure sensor by means of a Nano Carbon Piezoresistive Composite (NCPC). The sensor was fabricated using the 3D printing process. We designed a miniaturized cantilever-type sensor electrode to improve the pressure sensing performance and utilized a 3D printer to build a small-sized body. The sensor electrode was made of 2 wt％ MWCNT/epoxy piezoresistive nano-composite, and the sensor body was encapsulated with a pipe plug cap for easy installation to any pressure system. The piezoresistivity responses of the sensor were converted into stable voltage outputs by using a signal processing system, which is similar to a conventional foil strain gauge. We evaluated the pressure-sensing performances using a pressure calibrator in the lab environment. The 3D-printed cantilever electrode pressure sensor showed linear voltage outputs of up to 16,500 KPa, which is a 200％ improvement in the pressure sensing range when compared with the bulk-type electrode used in our previous work.

• Journal of Bio-Environment Control
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• v.16 no.2
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• pp.151-156
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• 2007

This work was conducted to investigate the important rooting factors through comparative analysis of a physiological differentiation after layering treatment using four apple rootstocks of different rooting abilities; M.26, M.9, O.3, and Mo.84. Mo.84 showed the highest rooting rate in from rootstocks, while O.3 was the lowest. Mo.84 also found to have the highest indole-3-acetic acid (IAA) content, although the fluctuation of IAA contents was not consistent with layering treatment. In contrast, abscisic acid (ABA) content of Mo.84 which showed highest rooting was lowest among rootstocks regardless of layering treatment. And ABA contents of all rootstocks were decreased after layering treatment than before layering treatment. O.3 which showed poor rooting rate revealed lowest in boron content. Carbohydrate/nitrogen (C/N) ratio of Mo.84 was the highest in all rootstocks. Therefor, we assumed that he IAA contents in layering treated rootstocks were not seemed to be a major rooting factor, but the changes in ABA contents and boron levels limit rooting in dwarf apple rootstocks.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.7 s.112
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• pp.762-768
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• 2006

To address the need for new intelligent sensing of systems, this study presents a novel strain sensor based on piezoresistivity of carbon nanotube (CNT) and its nanocomposites. Fabrication and characterization of the carbon nanocomposite material are discussed and an electrical model of the CNT strain sensor was derived based on electrochemical impedance spectroscopy analysis and strain testing. The dynamic response of the sensor on a vibrating beam was simulated using numerical analysis and it was compared with experimental test. The simulation showed good agreement with the strain response of the actual sensor.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.930-935
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• 2006

To address the need for new intelligent sensing of systems, this study presents a novel strain sensor based on peizoresistivity of carbon nanotube (CNT) and its nanocomposites. Fabrication and characterization of the carbon nanocomposite material are discussed and an electrical model of the CNT strain sensor was derived based on electrochemical impedance spectroscopy analysis and strain testing. The dynamic response of the sensor on a vibrating beam was simulated using numerical analysis and it was compared with experimental test. The simulation showed good agreement with the strain response of the actual sensor.

• Journal of Drive and Control
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• v.13 no.1
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• pp.43-48
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• 2016

This paper presents a preliminary study on the pressure sensing characteristics of smart nano composites made of MWCNT (multi-walled carbon nanotube) to develop a novel pressure sensor. We fabricated the composite pressure sensor by using a solution casting process. Made of carbon smart nano composites, the sensor works by means of piezoresistivity under pressure. We built a signal processing system similar to a conventional strain gage system. The sensor voltage outputs during the experiment for the pressure sensor and the resistance changes of the MWCNT as well as the epoxy based on the smart nano composite under static pressure were fairly stable and showed quite consistent responses under lab level tests. We confirmed that the response time characteristics of MWCNT nano composites with epoxy were faster than the MWCNT/EPDM sensor under static loads.

• Journal of The Korean Society of Grassland and Forage Science
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• v.28 no.2
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• pp.89-98
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• 2008

The purpose of this study was to suggest the basic data for establishment of wildflower pastures. The experimental design includes two treatments: Native wildflower pasture (NWP, Kentucky bluegrass + native wildflower 8 species) and Introduced wildflower pasture (IWP, Kentucky bluegass + introduced wildflower 24 species). The field trials were carried out on the experimental pastures plots at Chungnam National University throughout from Sep. 2006 to Dec. 2007. The results obtained are as fellows: In terms of the flower color in the wildflower pastures, the IWP was found more various than the NWP. But such problems as seasonal distribution and continuity were raised and moreover the time of flowering depended mainly upon the spring season. Even though the flower color in the NWP did not show up its variousness, seasonal distribution and continuity were found comparatively satisfactory. To perennially maintain the botanical composition, the variousness of wildflower species are found important after examining locally the beginning rearing and flowering characteristics of wildflowers as well as the basic turfgrass. Moreover, when the wildflower pastures was constructed in autumn, since most of the introduced wildflower were annuals, it maintained various botanical composition before wintering, but after wintering the botanical composition were found simplified due to the winter tolerance. The NWP did not show any problems in the winter tolerance but it could not make the botanical composition diversified. Accordingly, to maintain the wildflower pasture for many years, diversifying wildflower species based upon perennials including annuals seems to be good.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.39-39
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• 2020

호박(Cucurbita spp.)은 박과 호박속 식물로 원산지는 열대 남아메리카로 추정되며 1년생 혹은 다년생 초본으로서 우리나라를 포함한 전 세계에서 널리 분포하고 있다. 호박은 비타민A와 비타민C가 풍부하고 이뇨작용 효과가 탁월해 피부를 좋게 하고 부기를 빼주는 것으로 보고되고 있다. 본 연구에서는 농업유전자원센터에서 보유한 호박속 자원의 내력과 형태적인 특성을 그룹화하여 자원 활용을 위한 기초자료를 제공하고자 하였다. 농업유전자원센터에서 보유한 호박속 등록자원은 총 5종(C.pepo, C. moschata, C.maxima, C.argyrosperma, C .ficifolia) 1,640자원으로 주요 원산지는 한국 589자원(35.9%), 미국 122자원(7.4%), 러시아 79자원(4.8%), 멕시코 49자원(4.2%), 터키 56자원(3.4%)이었으며 국내 원산의 경우 강원도에서 수집된 자원이 66자원으로 가장 많았다. 전체 1,640 자원 중 재래종은 733자원(44.7%)을 차지하였으며 다음으로는 육성품종이 133자원(8%)으로 많았다. 생장형이 조사 된 301자원 대부분이 덩굴성이며 준왜성 16자원, 왜성 14자원이 있었다. 호박은 과실 모양과 색, 잎 모양, 줄기 모양 등 생육 특성이 매우 다양하게 조사 되었으며 과경 등 몇 가지 특징은 완벽하지 않지만 종(species)을 구분하는 간이적인 지표로 사용되는 것으로 조사되었다. 흰가루병 저항성 자원은 조사 된 1,170 자원 중 우리나라 재래종인 참호박(IT104575)을 포함한 7자원이 조사되었다. 293개 자원의 과실당도는 2.2~15.4brix까지 다양했으며 당도 12brix 이상 자원은 IT200650을 포함하여 6자원이 조사되었다. 본 연구에서 조사된 호박속 자원의 내력 및 생육 특성은 육종소재의 기초 정보로서 이용되고 있으며 자원 내력정보의 보완, 형질과 기능성 물질 분석 등 추가적인 연구를 통해 연구소재의 기초 정보로서 활용의 가치가 더 커질 것으로 보인다.

• Journal of Sensor Science and Technology
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• v.30 no.6
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• pp.388-394
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• 2021

The conventional microelectromechanical system (MEMS) process has been used to fabricate sensors with high costs and high-volume productions. Emerging 3D printing can utilize various materials and quickly fabricate a product using low-cost equipment rather than traditional manufacturing processes. 3D printing also can produce the sensor using various materials and design its sensing structure with freely optimized shapes. Hence, 3D printing is expected to be a new technology that can produce sensors on-site and respond to on-demand demand by combining it with open platform technology. Therefore, this paper reviews three standard 3D printing technologies, such as Fused Deposition Modeling (FDM), Direct Ink Writing (DIW), and Digital Light Processing (DLP), which can apply to the sensor fabrication process. The review focuses on strain/load sensors having both sensing material features and structural features as well. NCPC (Nano Carbon Piezoresistive Composite) is also introduced as a promising 3D material due to its favorable sensing characteristics.

• Journal of Astronomy and Space Sciences
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• v.21 no.4
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• pp.383-390
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• 2004

We describe the in-flight sensitivity calibration of the Far ultraviolet Imaging Spectrograph (FIMS, also known as SPEAR) onboard the first Korean science satellite, STSAT-1, which was launched in September 2003. The sensitivity calibration is based on a comparison of the FIMS observations of the hot white dwarf G191B2B, and two O-type stars Alpha-Cam, HD93521 with the HUT (Hopkins Ultraviolet Telescope) observations. The FIMS observations for the calibration targets have been conducted from November 2003 through May 2004. The effective areas calculated from the targets are compared with each other.

• Journal of Plant Biotechnology
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• v.32 no.3
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• pp.181-186
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• 2005

This work was conducted to evaluate the effects of rooting on tissue cultured M.9 (Malus domestica Bork. cv, tcM.9) after layering in field. We investigated an appearance period of first root in shoot, rooting ratio, contents of indole-3-acetic acid (IAA), abscisic acid (ABA), inorganic matters, sugars, and lignin in rooting areas of stems by layering. First root in shoot of tcM.9 and natural M.9 appeared 25 and 30 days after layering (DAL), respectively. Rooting ratio was much higher in tcM.9 than in natural M.9. The content of IAA was higher in tcM.9 than in natural M.9 before layering, but it was reversed at 20 and 30 DAL. In contrast, the content of ABA was much higher in natural M.9 than in tcM.9 in case of both before and 10 and 20 DAL. The contents of N, B, Mn, and Zn were significantly higher in tcM.9 than in natural M.9 both before and 10 and 20 DAL. The contents of sugars in tcM.9 had the similar pattern of the contents of inorganic materials. There were statistically significant differences in the contents of sucrose and glucose at 30 DAL as well as the content of maltose at 20 and 30 DAL. The content of lignin was significantly higher in tcM.9 than in natural M.9 before layering and 10 and 30 DAL while there was no difference 20 DAL. Therefore, improvement of rooting ability in the tissue cultured root stock M.9 might be due to the changes of inorganic matters or lignin rather than that of sugars and hormones.