• 한국작물학회지
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• 제34권4호
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• pp.434-439
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• 1989

벼 어린모의 육묘온도별 최소 육묘일수를 구명하고 육묘온도, 육교일수 및 배유제거유무에 따른 이앙후 초기생육을 조사한 결과를 요약하면 다음과 같다. 1. 벼 어린모 육묘시 육묘오도에 따른 최소 육묘일수를 맷트형성정도를 기준으로 보면 20/12$^{\circ}C$ 서/ 야)에서는 10일, 25/18$^{\circ}C$에서는 8일, 30/2$0^{\circ}C$에서는 6일어었다. 2. 벼 어린모 육묘시 유교온도에 따른 최소 육묘일수의 묘생육을 보면 초자은 8~12cm, 엽수(불완전엽 제외)는 1.5~1.7엽, 지상부 건물중은 개체당 6.9~7.5mg, 배유양분잔존율은 32~36%이었다. 3. 벼 어린모 육묘시 육묘온도에 따른 최소 육묘일수의 적산온도는 육묘온도에 따라 다소 다르나 150~17$0^{\circ}C$의 범위이었다.

• 한국소음진동공학회논문집
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• 제23권2호
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• pp.112-122
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• 2013

Recently the construction of stations under railway lines and railway sections passing through central area of cities are increasing, calling for an urgent establishment of countermeasures against railway vibration and its subsequent second-phase noise. Of technology developed up to now, the most efficient countermeasure is the floating slab track, a track system isolated from the sub-structure by springs. Unfortunately, however, the system design technology and technology for key components have not yet developed in Korea. As such, in this study, the analysis and design technology of floating slab track and its vibration isolator technology can be achieved. In preparation for future demands, it is expected to raise awareness for the need of technology self-support and to make a meaningful contribution to mitigating vibration and noise produced by the next-generation high-speed railway.

• 공학논문집
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• 제8권1호
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• pp.31-50
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• 2006

수축은 콘크리트에 균열을 발생시키는 경우도 있다. 일반적 조건하에서는 콘크리트의 건조를 피할 수 없으며 건조가 일어나면 수축이 생기므로 대부분의 콘크리트 적용분야에서는 실제로 이와 같이 균열발생을 고려하여야 한다. 균열이 발생한 콘크리트는 균열이 없는 콘크리트에 비하여 강도가 약하고 투과성이 크며 화학적 침식의 영향을 받기 쉽다. 또 재령의 경과에 따라 경량기포콘크리트의 강도발현은 기포제의 종류, 물과 시멘트와의 비, 양생조건 및 기간 등과 같은 인자에 의존하고 있다. 경량기포콘크리트의 강도가 높으면 높을수록 수축에 의하여 균열이 발생할 가능성이 감소한다. 그러므로 온돌구조용으로의 경량기포콘크리트의 강도는 소포율과 시멘트의 건조수축과의 균열저감효과에 크게 의존된다.

• 한국기계가공학회지
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• 제7권2호
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• pp.72-77
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• 2008

In this study, we propose and develop PDMS-based modular actuators. The microactuator which looks like a small insect uses thermal expansion power of the PDMS (polydimethylsiloxane; $sylgar^{(R)}$ 184 silicone elastomer). The PDMS-based microactuator provides a large displacement due to a high thermal expansion coefficient (approximately 310ppm). The microacruator with 1mm length $350{\mu}m$ width is optimized by using a numerical analysis. The shape of the PDMS actuatoris variously designed. They are placed at several positions to find the optimal position that provides a high transformation ratio. The PDMS-based microactuators are fabricated using a conventional micromaching technique. The fabricated microactuator is heated using a hot-plate. The actuator displacement is measured as a function of temperature from $27^{\circ}C$ to $300^{\circ}C$. The experimental results are compared to the simulation result. When heating temperature up to $300^{\circ}C$ is applied to the PDMS actuator, each V-groove-shaped joint is actuated $30{\mu}$ mat $300^{\circ}C$. Anotherdesign of the microactuator has a maximum displacement of about 656mm.

• 환경생물
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• 제22권1호
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• pp.184-191
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• 2004

To investigate bacteria with algalytic activities against Anabaena cylindrica when water blooming occurs and to study enzyme profiles associated with alga-lytic activity, various bacterial strains were isolated from surface waters and sediments in eutrophic lakes or reservoirs in Korea. Among 178 isolates, only nine isolates exhibited lytic abilities against A cylindrica on the agar plates, and then the isolate AK-13 was selected as the strongest in lysing the cyanobacterium A. cytindrica. The strain AK-13 was characterized and identified as Sinorhizobium sp. based on fatty acid methyl ether profiles and 16S rDNA sequence. According to the results of the enzyme assays, in the strain An-13 of Sinorhizobium sp., alginase, amylase, proteinase (caseinase and gelatinase), carboxymethyl-cellulase (CMCase), laminarinase, and lipase was produced, namely CMCase, laminarinase and protease were highly active. None of glycosidase was produced. Therefore, enzyme systems of Sinorhizobium sp. AK-13 were very complex to degrade cell walls of A. cylindrica. The peptidoglycans of A. cylindrica mat be hydrolyzed and metabolized to a range of easily utilizable monosaccharides or other low molecular weight organic substances by Sinorhizobium sp. AK-13.

• 한국재료학회지
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• 제27권9호
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• pp.471-476
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• 2017

In order to improve the high temperature oxidation resistance and lifespan of mat type porous carbon insulation, SiC was coated on carbon insulation by solution coating using polycarbosilane solution, curing in an oxidizing atmosphere at $200^{\circ}C$, and pyrolysis at temperatures up to $1200^{\circ}C$. The SiOC phase formed during the pyrolysis process was converted into SiC crystals as the heat treatment temperature increased, and a SiC coating with a thickness of 10-15 nm was formed at $1600^{\circ}C$. The SiC coated specimen showed a weight reduction of 8.6 % when it was kept in an atmospheric environment of $700^{\circ}C$ for 1 hour. On the other hand, the thermal conductivity was 0.17 W/mK, and no difference between states before and after coating was observed at all.

• Journal of Power Electronics
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• 제19권5호
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• pp.1074-1086
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• 2019

This paper presents the design and implementation of an improved cascaded multilevel inverter topology with asymmetric DC sources. This experimental inverter topology is a stand-alone system with simulations and experiments performed using resistance loads. The topology uses four asymmetric binary DC sources that are independent from each other and one H-bridge. The topology was simulated using PSIM software before an actual prototype circuit was tested. The proposed topology was shown to be very efficient. It was able to generate a smooth output waveform up to 31 levels with only eight switches. The obtained simulation and experimental results are almost identical. In a 1,200W ($48.3{\Omega}$) resistive load application, the THDv and efficiency of the topology were found to be 1.7% and 97%, respectively. In inductive load applications, the THDv values were 1.1% and 1.3% for an inductive load ($R=54{\Omega}$ dan L=146mH) and a 36W fluorescent lamp load with a capacitor connected at the dc bus.

• The Journal of Asian Finance, Economics and Business
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• 제9권10호
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• pp.85-96
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• 2022

CEO duality and its impact on firm performance represent one of the most contentious issues in both academia and business. This study, therefore, aims to examine the moderating role of CEO duality in the relationship between intellectual capital Efficiency (human, structural, relational, Capital Employed, and Innovation) and firm performance (earnings per share and Tobin's Q) among Jordanian companies. The study sample consists of services listed companies on Amman Stock Exchange. The study used panel data for the period 2014-2018 with a sample size of 230 observations. SPSS software was used to analyze the collected data. The regression results indicate a significant relationship between, IC and firm performance. When CEO Duality is incorporated into the model as a moderator, there is an increase in the R² by 7.9%. The findings from this study expand the theoretical underpinning of corporate governance research by identifying the performance implications of CEO duality within the Jordanian context. It also contributes significantly to the literature review about the current status of the practices taken in the intellectual capital components efficiency among companies listed on the Amman Stock Exchange. Findings from this study also provide contributions to the concerned policymakers such as the Ministry of Finance, Securities Commission, and Amman Stock Exchange in Jordan, to improve the current policies related to intellectual capital efficiency.

• 한국식품영양학회지
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• 제35권6호
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• pp.543-551
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• 2022

There has been increased interest in lignans due to their potential effect in reducing the risk of developing several diseases. To evaluate lignan contents, sensitive and accurate methods should be developed for their quantification in food. The present study aimed to validate a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of 5 lignans: lariciresinol (Lar), matairesinol (Mat), pinoresinol (Pin), secoisolariciresinol (Seco), and syringaresinol (Syr). The validation included selectivity, linearity, recovery, accuracy, and precision. The method was proved to be specific, with a linear response (R²≥0.99). The limits of detection were 0.040~0.765 ㎍/100 g and the limits of quantification were 0.114~1.532 ㎍/100 g. Recoveries were 90.588~109.053% for black sesame powder. Relative standard deviations of repeatability and reproducibility were below 5%. Total lignan contents of roasted coffee bean, oat, and blacksoy bean were 105.702 ㎍/100 g, 78.965 ㎍/100 g, and 165.521 ㎍/100 g, respectively. These results showed that LC-MS/MS analysis would be effective in producing acceptable sensitivity, accuracy, and precision in five lignan analyses.

• 한국버섯학회지
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• 제21권3호
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• pp.83-87
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• 2023

The importance of biocomposites has increased owing to the changes in global consumption trends and rapid climate change. Technologies using mushroom mycelium cultivation, and molding methods for mycelial application have gained attention as potential strategies for producing eco-friendly composites. Currently, mushroom mycelia are used as raw materials for food and cosmetics; however, research on their utilization as biocomposite materials is limited. Therefore, the potential for the development of mushroom mycelium-related products and technologies is high. This review analyzes the domestic and international patent application trends related to the technologies for composite (packaging, insulation, adhesives, and leather) and food (substitute for meat) materials using mushroom mycelium, as an eco-friendly biocomposite material, to provide objective patent information that can further research and development (R&D) in this field.