• 폴리머
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• 제32권3호
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• pp.270-275
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• 2008

고무재료의 피로균열 성장특성은 고무제품의 강도와 내구성을 평가하는 매우 중요한 요소이다. 본 연구에서는 자체 제작한 피로균열 성장 측정기를 이용하여 충전제 종류에 따른 EPDM의 피로균열 성장특성을 고찰하였다. 피로균열성장은 진동수와 측정온도에 영향을 받았으며, 진동수가 증가함에 따라 균열성장속도는 감소하였고 온도가 증가함에 따라 균열성장속도는 증가하였다. 충전된 EPDM의 인열에너지와 균열성장속도의 상관관계는 지수법칙을 따랐으며, 충전제의 함량이 증가함에 따라 균열성장속도가 감소하였다. 또한, 실리카로 충전된 EPDM이 카본블랙으로 충전된 EPDM에 비해 더 우수한 피로저항 특성을 보였다. 실리카로 충전된 경우, 균열성장속도는 30 phr까지 감소하다가 그 이후 다시 증가하였다. 미충전 시편의 피로 파괴단면 SEM 사진에서 작고 유연한 파괴자국들이 관찰되었으며, 실리카가 충전된 시편의 단면에서는 보강효과로 인하여 인열 형태가 불규칙 적이고 비교적 거친 표면이 관찰되었다.

• 한국자기학회지
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• 제25권5호
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• pp.144-148
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• 2015

스피넬 결정구조를 지니는 $CoMn_2O_4$ 박막을 증착하였으며 이들 박막의 물리적 특성을 후열처리 이전과 이후로 비교 조사하였다. 증착온도인 $720^{\circ}C$보다 낮은 $700^{\circ}C$에서의 후열처리 과정 이후, 열처리 이전의 불분명했던 tetragonal 결정구조가 분명하여졌으며 이는 곧 표면상태의 변화로도 관측되었다. 자성특성의 경우 약 100 K에서 다결정 형태의 벌크에서는 측정할 수 없었던 상전이가 관측되었다. 상전이온도 이상의 온도에서는 전형적인 강자성 특성을 보이는 반면 상전이온도 이하에서는 페리자성 특성을 보였다. 특히 열처리 이후에는 페리자성 특성은 매우 뚜렷하여졌다. 이와 같은 결과는 후열처리과정이 $CoMn_2O_4$ 박막의 물리적 특성을 결정짓는데 필수적임을 의미한다.

• Journal of Biosystems Engineering
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• 제39권4호
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• pp.318-323
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• 2014

Purpose: This study was carried out to predict the growth period and fresh weight of sprouts grown in a cultivator designed to grow sprouts under optimal conditions. Methods: The temperature, light intensity, and amount of irrigation were controlled, and images of seed sprouts were acquired to predict the days of growth and weight from pixel counts of leaf area. Broccoli, clover, and radish sprouts were selected, and each sprout was cultivated in a 90-mm-diameter Petri dish under the same cultivating conditions. An image of each sprout was taken every 24 hours from the 4th day, and the whole cultivating period was 6 days, including 3 days in the dark. Images were processed by histogram inspection, binary images, image erosion, image dilation, and the overlay image process. The RGB range and ratio of leaves were adjusted to calculate the pixel counts for leaf area. Results: The correlation coefficients between the pixel count of leaf area and the growth period of sprouts were 0.91, 0.98, and 0.97 for broccoli, clover, and radish, respectively. Further, the correlation coefficients between the pixel count of leaf area and fresh weight were 0.90 for broccoli, 0.87 for clover, and 0.95 for radish. Conclusions: On the basis of these results, we suggest that the simple image acquisition system and processing algorithm can feasibly estimate the growth period and fresh weight of seed sprouts.

• Journal of Microbiology and Biotechnology
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• 제19권6호
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• pp.560-565
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• 2009

We isolated nine endophytic fungi from the roots of salt-stressed soybean cultivar Daewonkong and screened them for growth-promoting secondary metabolites. Of all fungal isolates, P-4-3 induced maximum growth promotion of waito-c rice and soybean. Analysis of the culture filtrate of P-4-3 showed the presence of physiologically active gibberellins $GA_1$, $GA_3$, $GA_4$, and $GA_7$, along with physiologically inactive $GA_{15}$ and $GA_{24}$. The plant growth promotion and gibberellin-producing capacity of P-4-3 was much higher than wild-type Gibberella fujikuroi, which was taken as the control during the present study. The fungal isolate P-4-3 was identified as a new strain of Scolecobasidium tshawytschae through the morphological characteristics and phylogenetic analysis of 18S rDNA sequence. Gibberellins production and plant growth promoting ability of genus Scolecobasidium was reported for the first time in the present study.

• Fisheries and Aquatic Sciences
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• 제20권10호
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• pp.24.1-24.8
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• 2017

The experiment was conducted to investigate the effects of different algae in diet on growth, survival, and interleukin-10 productions of sea cucumber. At first, a 9-week feeding trail was conducted to evaluate the growth performance and survival of the sea cucumber fed one of the six experimental diets containing ST (Sargassum thunbergii), UL (Ulva lactuca), UP (Undaria pinnatifida), LJ (Laminaria japonica), SS (Schizochytrium sp.), and NO (Nannochloropsis oculata) in a recirculating aquaculture system. The result showed that survival was not significantly different among the dietary treatments, and the specific growth rate (SGR) of sea cucumber fed the UL diet ($1.58%d^{-1}$) was significantly higher than that of sea cucumber fed the other diets (P < 0.05), except for the LJ and NO diets. Secondly, interleukin (IL)-10 gene expression was determined where mice splenocytes were stimulated with $10{\mu}g\;ml^{-1}$ of sea cucumber extracts for 2 h. The result showed that IL-10 gene expression levels were significantly increased in UL, LJ, and NO diets fed sea cucumber extracts compared to other experimental diets. The results suggest that dietary inclusion with Ulva lactuca, Laminaria japonica, and Nannochloropsis oculata algae may improve the growth of juvenile sea cucumber and could upregulate IL-10 gene expression in mice splenocytes. Such detailed information could be helpful in further development of more appropriate diets for sea cucumber culture.

• 한국토양비료학회지
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• 제43권4호
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• pp.514-521
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• 2010

지속가능한 친환경농업을 위해서는 비료와 함께 식물생장촉진 미생물 또는 생장조절물질을 적절히 혼합 사용하는 것이 바람직하다. 본 연구에서는 Methylobacterium oryzae CBMB20의 근권토양접종과 메탄올 엽면살포에 따른 고추의 생육촉진 효과를 유기질 비료의 시용 수준별로 조사하였다. M. oryzae CBMB20의 근권토양접종과 메탄올 엽면살포는 각기 고추생육을 증대시켰다. 또한 이들을 동시에 혼합 처리하였을 경우에는 고추의 생장촉진 효과가 더욱 현저하게 나타났다. M. oryzae CBMB20의 근권토양접종과 메탄올 엽면살포에 따른 고추 생장촉진 효과는 유기질 비료의 시용수준이 낮은 경우에 더욱 현저하게 나타났다. M. oryzae CBMB20와 메탄올을 혼합 처리한 경우 권장시비수준 100%와 300% 처리 사이에 고추생육과 수량에서 유의성 있는 차이가 없었다. 시비량이 지나치게 많을 경우 생장촉진제의 처리효과를 거둘 수 없으며, 적정한 시비 수준에서 M. oryzae CBMB20와 메탄올을 혼합 처리함으로써 고추를 비롯한 작물의 생장과 수량을 유지하면서도 시비량을 크게 줄일 수 있을 것으로 판단된다.

• Asian Journal of Innovation and Policy
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• 제6권1호
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• pp.94-110
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• 2017

This paper approaches knowledge capital as social infrastructure and analyzes its impact on economic growth. To this end, we constructed a panel dataset for 120 countries for the years 2000-2014 and estimated the economic growth function using the panel analysis. As proxies for knowledge capital, we used the R&D expenditure per capita and the number of patent applications per thousand people in each country, both measured in stock. Economic growth was measured in terms of real GDP per capita and real value added per capita at the industry level. The empirical findings demonstrate that knowledge capital accumulated in a society significantly promotes economic growth. Especially R&D stock increases real value added per capita in all industries-not only manufacturing, but also services and agriculture-implying substantial inter-industry spillover effects. The findings of this study suggest that knowledge capital boosts economic growth as core social infrastructure.

• 한국환경복원기술학회지
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• 제2권1호
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• pp.66-71
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• 1999

Main concern is to figure out the growth response of Pinus densiflora to hydrologic conditions in the central Korea. Continuous measurements were carried out with six trees with dendrometers in the Chungbuk National University experimental forest (Wolak-san) during 1995~1996. Surrounding hydrological conditions reflected by the solar radiation, air temperature, precipitation, soil water were included in measurements. Their effects on the biological response of trees was investigated and expressed as response functions. With these response functions, tree growth model was developed. Soil water availability was more related to the tree growth than air temperature. Limited number of biological measurements with dendrometer could permit determination of dynamics of radial tree growth to the hydrological conditions. Tree growth model could be used to check and revise the statistical transfer function of dendrohydrology.

• Preventive Nutrition and Food Science
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• 제16권4호
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• pp.386-389
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• 2011

Previous studies have confirmed that fermented whey produced by Leuconostoc mesenteroides CJNU 0147 or Lactobacillus casei CJNU 0588 display bifidogenic growth stimulator (BGS) activity. The present study sought to determine if the strain itself can improve the growth of bifidobacteria in co-cultures. In reinforced clostridial medium (RCM), both strains stimulated the growth of a Bifidobacterium lactis strain during the exponential phase and also stimulated the growth during almost all growth phases in whey broth. Fermented whey containing viable Leu. mesenteroides CJNU 0147 and L. casei CJNU 0588 cells maintained viability of the B. lactis strain stored at $10^{\circ}C$ in MRS broth. Viable cell count of the B. lactis strain without the fermented whey was decreased to 5.6 log cfu/mL after 15 days, whereas that of the strain with the fermented whey was slightly increased to 7.1 log cfu/mL as compared with initial viable cell count of 6.9 log cfu/mL.

• 한국직업건강간호학회지
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• 제25권3호
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• pp.141-147
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• 2016

Purpose: The objective of this study is to identify the effects of self-esteem and problem focused coping on post-traumatic growth among police officers. Methods: The data were collected from the 137 police officers in ten police offices of G city in July 2014. The collected data were analyzed for descriptive statistics, t-test, ANOVA, Pearson's correlation coefficient, and hierarchical regression using the SPSS/WIN 18.0 program. Results: Post-traumatic growth was positively correlated with self-esteem and problem focused coping. Self-esteem and problem focused coping had a significant effects on post-traumatic growth. The explained variance for post-traumatic growth was 19.0%. Conclusion: To improve post-traumatic growth of police officers, strategies to increase self-esteem and problem focused coping are needed.