• 한국염색가공학회지
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• 제11권2호
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• pp.27-37
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• 1999

Polypropylene(PP) films were treated with plasma glow discharge to produce peroxy radicals on the surfaces. The peroxy radicals formed on the PP film surfaces were subsequently used for the graft polymerization of acrylic acid and acrylamide in an aqueous solution by heating, respectively. Introduction of acrylic acid and acrylamide on the PP film could be confirmed by the observation of carbonyl and primary amine absorptions based on carboxylic acid and amide, respectively. And introduction of functional group could be confirmed by weight analysis and ESCA. The water contact angle(90$^{\circ}$) of PP film was constant, irrespective of elapsed time, while plasma-treated and functional monomer-grafted PP films were slowly increased with elapsed time, showing the rearrangement of surface polar groups in air condition. The water contact angle$(90^\circ)$ of PP film was decreased by the plasma treatment$(56^\circ)$ and further decreased by the grafting of acrylic acid$(34^\circ)$ and acrylamide$(37^\circ)$, indicating increased hydrophilicity of the modified surfaces. The water contact angle of plasma-treated PP film increased a little as time elapsing. The half-life periods of surface voltage on acrylic acid-(31sec) and acrylamide-grafted PP(42sec) were significantly decreased when compared to those on PP(950sec) and plasma-treated PP film(241sec). In the experiments using acid, basic and disperse dyes, absorbance and $\Delta{E}$ values of functional monomer-grafted PP films were significantly increased than that of oxygen plasma-treated one.

• 한국작물학회지
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• 제29권1호
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• pp.62-66
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• 1984

옥수수 변형단교잡종 채종재배에 있어서 웅주간파 ♂♀ 1 : 2, 2 : 4 등의 파종양식과 재식밀도가 종자친의 생육 및 채종량과 화분친의 웅수특성에 미치는 영향을 구명하고자 1983년 제천옥의 종자친 KS8/B68과 화분친 KS5를 공시하여 시험한 결과를 요약하면 다음과 같다. 1. 개화기 및 간장은 파종양식이나 재식밀도에 크게 영향을 받지 않았고 종자친의 착수고는 파종양식간에는 차이가 없었으나 재식밀도가 증가함에 따라 직선적으로 증가하였다. 2. 종자친의 100주당 수수는 10a당 종자친 3,500본에서는 파종양식간에 비슷하나 5,000본 이상에서는 2 : 4 재배보다 웅주간파나 1 : 2재배에서 많았으며 재식밀도 증가에 따라 파종양식에 관계없이 직선적으로 감소하였다. 수당입수는 파종양식간에는 차이가 없고 파종양식과 재식밀도의 상호작용도 유의하지 않았으나 재식밀도 증가에 따라 작아졌다. 100입중은 25g 내외로 처리간 차이가 없었다. 3. 화분친의 화분이 제한되지 않은 조건에서의 채종량은 웅주간파, 1 : 2재배, 2 : 4재배순으로 많은 경향이였고 10a당 종자 친 3,500본에서 5,000본으로 증가시킴에 따라 크게 증가하나 5,000본에서 6,500본으로 재식밀도 증가에 따른 채종량 증가는 크지 않았다. 4. 화분친의 웅수장과 웅수당 영화수는 1 : 2나 2 :4재배에 비하여 웅주간파 재배에서 작았고 재식밀도 증가에 따라 1 : 2 및 2 : 4재배에서는 크게 감소하였으나 2: 4재배에서는 유의하게 작아지지 않았다. 5. 변형단교잡종의 채종에는 1 : 2나 2 : 4재배의 10a당 종자친 5,000본 재식이 적합할 것으로 생각된다.

• Journal of Public Diplomacy
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• 제2권1호
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• pp.136-142
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• 2022

• The Korean Journal of Physiology and Pharmacology
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• 제7권4호
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• pp.211-215
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• 2003

To examine the localization pattern of phospholipase D2 (PLD2) in the pancreatic islet (the islet of Langerhans) depending on species, we conducted a morphological experiment in the rat and guinea pig. Since individual islets display a typical topography with a central core of B cell mass and a peripheral boundary of A, D, and PP cells, double immunofluorescent staining with a panel of antibodies was performed to identify PLD2-immunoreactive cells in the islets PLD2 immunoreactivity was mainly present in A and PP cells of the rat pancreatic islets. And yet, in the guinea pig, PLD2 immunoreactivity was exclusively localized in A cells, and not in PP cells. These findings suggest a possibility that PLD2 is mainly located in A cells of rodent pancreatic islets, and that the existence of PLD2 in PP cells is not universal in all species. Based on these results, it is suggested that PLD2 may play a significant role in the function of A and/or PP cells via a PLD-mediated signaling pathway.

• 한국터널지하공간학회 논문집
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• 제23권5호
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• pp.303-314
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• 2021

세그먼트 라이닝의 고품질/고강성/고강도화에 따라 세그먼트 라이닝을 터널의 최종 라이닝으로 삼는 경우가 증가하고 있다. 프리캐스트 콘크리트 라이닝은 현장타설 콘크리트에 비해 품질 및 강도가 높다. 역설적으로 이러한 점은 터널 내 화재 시 콘크리트의 손상을 더 크게 하는 요인이 된다. 본 연구에서는 PP 섬유와 같은 합성섬유를 이용한 내화방법에서 섬유함유량에 따라 세그먼트 라이닝의 화재저항성능을 파악하기 위한 시험을 수행하였다. 그 결과, PP섬유 1.5 kg/m³ 사용 시 관련 프로젝트에서 요구한 화재저항성능을 확보할 수 있음을 확인하였다. 더불어 유사한 함성섬유인 PET를 사용하였을 경우와 PP섬유의 결과를 비교한 결과, PP섬유가 PET섬유를 사용하였을 경우에 비해 더 좋은 화재저항성능이 나타냄을 알 수 있었다.

• 한국터널지하공간학회 논문집
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• 제21권3호
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• pp.433-452
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• 2019

본 연구는 구조용 합성섬유(PP섬유) 혼입량에 따른 숏크리트 보강성능과 적정한 평가방법에 관한 것으로, 강섬유($37.0kg/m^3$)와 구조용 합성섬유(PP섬유) 혼입량을 매개변수($5.0kg/m^3$, $7.0kg/m^3$, $9.0kg/m^3$)로 설정하여 숏크리트 압축강도, 휨강도 및 휨인성 시험을 수행하였다. 특히, 판상의 숏크리트 에너지 흡수능력을 평가하기 위하여 원형 패널 휨인성 시험(Road and Traffic Authority, RTA)을 수행하였다. 검토결과, 압축강도 및 휨강도는 강섬유 보강 숏크리트가 다소크나, 실질적인 숏크리트 보강성능를 나타내는 휨인성은 구조용 합성섬유(PP섬유) 보강 숏크리트가 큰 것으로 분석됨에 따라, 강섬유 보강 숏크리트 대비 동등 이상의 보강효과를 발휘하는 것으로 검토되었다. 또한, 구조용 합성섬유(PP섬유) 혼입량에 따른 휨인성 및 에너지 흡수능력 상관관계에 의하면, 보시편 휨인성 시험(KS F 2566)의 허용기준 3.0 MPa이하조건에서 에너지 흡수능력이 발휘(A등급: 2.55 MPa = 202J, B등급: 2.72 MPa = 282J, C등급: 3.07 MPa = 403J)되는 것으로 검토되었다. 국내 터널현장에서 보수적으로 측정되는 강도개념의 숏크리트 휨인성(>3.0 MPa)을 본 연구의 숏크리트 에너지 흡수능력 상관관계로 지보성능을 평가할 경우, 보다 실질적이고 신뢰도 높은 숏크리트 지보성능 평가가 가능할 것으로 판단된다.

• Journal of Applied Biological Chemistry
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• 제54권1호
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• pp.33-40
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• 2011

Ionizing radiation can be used to improve the color of green tea extract to brighter. As a result, the irradiated green tea extract can be applied easier and broader in food or cosmetic industry. To confirm the retention of the biological activities of the cosmetic products added with green tea polyphenols (PPs), the real cosmetic products including a skin lotion (PS) and an essence (PE) cream were manufactured. Irradiation also applied to the manufactured cosmetic products to see their improvement of color and changes of biological activity. The PP showed 72% of electron donating ability (EDA) at a 5 ppm concentration and the PS and PE containing 2% PP showed higher than 60%, which was similar inhibition activity to vitamin C. The inhibition of superoxide dismutase (SOD)-like activity of PP, PS, and PE were higher than 55% at a 500 ppm concentration and the inhibition of xanthine oxidase (XOase) were also higher than 65% at a 200 ppm concentration. The measurement of lipid oxidation by addition of $Cu^{2+}$ and $Fe^{2+}$ as prooxidants showed that PP and PS had higher metal chelating ability for $Fe^{2+}$ than that of PE and the ability increased by increase of polyphenol concentration isolated from green tea. The $Cu^{2+}$ chelating ability of PP and PS showed higher than 90% at a 200 ppm concentration. Therefore, it is concluded that addition of PP in manufacturing PS and PE retains its biological activities including EDA, inhibition of XOase and SOD-like activity, and metal chelating ability in the manufactured cosmetic products. In addition, irradiation of PS and PE improved color of the products containing PP brighter without any adverse changes in biological activity of the products.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.530-533
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• 1998

In this paper, a new scheme of a boosted voltage generator (BVG) is designed for low powr DRAM's. The designed BVG can supply stable $V_{pp}$ using a new circuit operting method. This method controls charge pumping capability by switching the supply voltage and ring oscillator frequency of driving circuit, so the BVG can save area and reduce the powr dissipation during $V_{pp}$ maintaining period. The charge pumping circuit of the BVG suffers no $V_{T}$ loss and is to be applicable to low-voltage DRAM's. $V_{pp}$ level detecting circuit can detect constant value of $V_{pp}$ against temperature variation. The level of $V_{pp}$ varies -0.55%~0.098% during its maintaining period. Charge pumping circuit can make $V_{pp}$ level up to 2.95V with $V_{cc}$ =1.5V. The degecting level of $V_{pp}$ level detecting circuit changes -0.34% ~ 0.01% as temperature varies from -20 to 80.deg. C. The powr dissipation during V.$_{pp}$ maintaining period is 4.1mW.W.1mW.

• ALGAE
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• 제37권4호
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• pp.265-279
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• 2022

The primary production (PP) by phytoplankton in marine ecosystems is essential for carbon cycling and fueling food webs. Hence, estimating the PP in the territorial sea of each country is a necessary step to achieving carbon neutrality. To estimate the PP in the territorial sea of the Republic of Korea from 2005 to 2021, we analyzed various physiochemical parameters, such as sea surface temperature (SST), Secchi depth, and concentrations of chlorophyll-a and nutrients in the seas of five regions, including the East Sea, West Sea, western South Sea, eastern South Sea, and the waters off Jeju Island. During the 17-year study period, the SST tended to increase, while the nutrient concentrations declined, except in the Jeju area. Overall, the PP did not show a specific temporal trend, but daily PP in the western South Sea was the highest among the five regions. Moreover, the maximum PP in the Korean territorial waters (76,450 km²) was estimated at 11,227 Gg C y^-1, which accounts for 0.03% of the global PP. The results may give insights into a better understanding of the PP, further resource utilization, and environmental sustainability in the studied region.

• Macromolecular Research
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• 제17권2호
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• pp.110-115
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• 2009

The electrical, morphological and rheological properties of melt and dry mixed composites of poly ethylene (PE)/graphite (Gr), polypropylene (PP)/Gr and PP/nickel-coated carbon fiber (NCCF) were investigated as a function of filler type, filler content and processing temperature. The electrical conductivities of dry mixed PP/NCCF composites were increased with decreasing processing temperature. For the melt mixed PP/NCCF composites, the electrical conductivities were higher than those of the melt mixed PE/Gr and PP/Gr composites, which was attributed to the effect of the higher NCCF aspect ratio in allowing the composites to form a more conductive network in the polymer matrix than the graphite does. From the results of morphological studies, the fillers in the dry mixed PP/NCCF composites were more randomly dispersed compared to those in the melt mixed PP/NCCF composites. The increased electrical conductivities of the dry mixed composites were attributed to the more random dispersion of NCCF compared to that of the melt mixed PP/NCCF composites. The complex viscosities of the PP/Gr composites were higher than those of the PP/NCCF composites, which was attributed to the larger diameter of the graphite particles than that of the NCCF. Furthermore, the fiber orientation in the 'along the flow' direction during melt mixing was attributed to the decreased complex viscosities of the melt mixed PP/NCCF composites compared those of the melt mixed PP/Gr composites.