• Title/Summary/Keyword: polar energy

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Surface Composition Change of UV/Ozone Modified Polypropylene (UV/오존에 의해 개질된 폴리프로필렌의 표면 조성 변화)

  • Kim, J.I.;Ryu, S.H.
    • Elastomers and Composites
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    • v.37 no.1
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    • pp.49-56
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    • 2002
  • Polypropylene is oxidized with UV/ozone as a function of UV treatment time and ozone flow rate and its surface characteristics are investigated using contart angle measurements and XPS. The aging behavior of oxidized surface is investigated under air, water and ethylene glycol as the aging media. Adhesion strength is also investigated using a lap shear test. Polar surface energy increases with increasing UV/ozone treatment time as well as ozone flow rate. No polar surface energy change is observed under water aging, while under air aging it decreases significantly within 2-3 days and reaches the close value as that of the untreated PP. Adhesion strength increases with increasing UV/ozone treatment time as well as ozone flow rate.

Polymer Layer Effects on Anchoring Strength and Surface Ordering in NLC, 5CB, by the Washing Process after Rubbing on the Polyimide Surfaces

  • Lee, S.K.;Lee, J.U.;Han, J.M.;Hwang, J.Y.;Seo, D.S.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.11a
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    • pp.506-509
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    • 2003
  • The liquid crystal (LC) aligning capabilities by the washing processes after rubbing on the two kinds of the rubbed polyimide (PI) surface were studied. The polar anchoring energy of 4-n-pentyl-4'-cyanobiphenyl (5CB) increased with the rubbing strength RS on the two kinds of the rubbed PI surface. The polar anchoring energy of 5CB on the rubbed PI surface with alkyl side chains is larger than the rubbed PI surface with CONH moiety. Also, the surface ordering of 5CB on the rubbed PI surface with alkyl side chains is larger than the rubbed PI surface with CONH moiety. Therefore, the surface ordering of 5CB strongly depends on the polymers and washing process.

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Photoionization of N,N,N',N'-Tetramethyl-p-phenylenediamine in Polar Solvents

  • Min Yeong Lee;Du Jeon Jang;Minyung Lee;Du-Jeon Jang;Dongho Kim;Sun Sook Lee;Bong Hyun Boo
    • Bulletin of the Korean Chemical Society
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    • v.12 no.4
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    • pp.429-433
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    • 1991
  • The photoinduced electron transfer reactions of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) in various polar solvents were studied by measuring time-resolved fluorescence. The temperature dependence on the fluorescence decay rate in acetonitrile, methanol, ethanol and buthanol was carried out to obtain the activation energy and Arrehnius factor for the photoinduced electron transfer reaction. It was found that as the dielectric constant of the solvent increases, the activation energy and the reaction rate increase. This implys that the Arrehnius factor is important in controlling the photoinduced electron transfer reaction rate. In water, TMPD exists in three forms (cationic, protonated and neutral forms) due to the high dielectric constant and strong proton donating power of water. The photoinduced electron transfer reaction was found to be very fast (< 50 ps) and also the long liverd component in the fluorescence decay profile attributable to the photoexcited protonated form of TMPD was observed. Probably, the reaction pathway and the reaction coordinate seem to be different depending on the solvents studied here.

The Trends and Outlook of Technology Development for Oil and Gas in the Arctic (북극 석유·천연가스 자원 기술개발 현황 및 전망)

  • Lim, Jong-Se;Shin, Hyo-Jin;Kim, Ji-Su;Jin, Young-Keun
    • Ocean and Polar Research
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    • v.36 no.3
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    • pp.303-318
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    • 2014
  • The rising global demand for energy resources may lead to greater interest in the Arctic region. Since it has various resources, such as oil and gas, and large potential as a strategic location in exploration and production (E&P), there is likely to occur island sovereignty issues between the five arctic costal states and other countries. While global warming has led to the opening of the Northeast Passage and the Northwest Passage, several obstacles may impede the development of this area such as the low temperature environment, infrastructure problems in a limited area, flow assurance, environmental regulations, etc. To overcome these problems, various techniques have been applied in the exploration, development, production, transportation, and environment fields and it seems to be made technical development in extreme environment. In this study, the E&P status of representative states and development technologies in the Arctic region have been summarized with regard to carrying out E&P related to drilling, development, production, and operation in oil and gas fields. Furthermore, environmental factors have been taken into account to enhance progress with regard to E&P and ensure sustainable development in the Arctic. On that basis, it will be possible to secure oil and gas field development, production technology and R&D infrastructure in the Arctic.

Demonstration of 10kw Wind Turbine System at the King Sejong Station (극한환경에서의 소형풍력발전 실증운전)

  • Kim, Seok-Woo;Kyong, Nam-Ho
    • Journal of the Korean Solar Energy Society
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    • v.26 no.4
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    • pp.25-30
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    • 2006
  • 10kW wind turbine has been successfully commissioned at the King Sejong station in April, 2006. The wind turbine installed is a part of the R&D program for developing a solid wind/diesel hybrid power control system for a remote area such as Antarctica. At the same time, the current research aims to develop an anti-icing and de-icing technologies for a small wind turbine rated under 50kW. Since its commissioning, the turbine has generated about 500kWh for 47days without any system faults. Although sufficient data have not been obtained yet, any trouble has not occurred in the wind/diesel hybrid system based on the current analysis. Concerning on the environmental impact by the wind turbine operation, the turbine is installed within the station boundary in order to meet the Madrid protocol. Therefore, wind turbine operation meets the international requirements for preservation of antarctic ecosystem.

Electrorheological Behavior of the Hollow PANI Sebacate Suspension upon Application of the Electric Field

  • Choi, Ung-Su;Lee, Sang-Soon
    • KSTLE International Journal
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    • v.10 no.1_2
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    • pp.13-16
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    • 2009
  • The electrorheological(ER) behavior of hollow polyaniline(PANI) sebacate suspension in silicone oil was investigated by varying the electric fields and shear rates, respectively. The hollow PANI sebacate susepnsion acted as a typical Bingham fluid caused by the polarizability of an amide polar group and showed shear yield stress due to the formation of chains upon application of an electric field. The shear stress for the hollow PANI sebacate suspension exhibited an electric field power of 1.24. On the basis of the experimental results, the newly synthesized hollow PANI sebacate suspension was found to be an anhydrous ER fluid.

Influence of Surface Treatment of Polyimide Film on Adhesion Enhancement between Polyimide and Metal Films

  • Park, Soo-Jin;Lee, Eun-Jung;Kwon, Soo-Han
    • Bulletin of the Korean Chemical Society
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    • v.28 no.2
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    • pp.188-192
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    • 2007
  • In this work, the effects of chemical treatment of polyimide films were studied by FT-IR, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and contact angles. The adhesion characteristics of the films were also investigated in the peel strengths of polyimide/aluminum films. The increases of surface functional groups of KOH-treated polyimide films were greatly correlated with the polar component of surface free energy. The peel strength of polyimides to metal substrate was also greatly enhanced by increasing the KOH treatment time, which can be attributed to the formation of polar functional groups on the polyimide surfaces, resulting in enhancement of the work of adhesion between polymer film and metal plate.

Monitoring on the Marine Environment and Phytoplankton of Kongsfjorden, Svalbard, Arctic (북극 스발바드섬 Kongsfjorden의 해양 환경 및 식물플랑크톤 모니터링 연구)

  • Kang, Sung-Ho;Kim, Yea-Dong;Kang, Jae-Shin;Yoo, Kyu-Cheul;Yoon, Ho-Il;Lee, Won-Cheol
    • Ocean and Polar Research
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    • v.25 no.2
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    • pp.213-226
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    • 2003
  • Kongsfjorden near Korean Arctic Station, Dasan, is a glacial fjord in the Svalbard archipelago, Arctic that is influenced by both Atlantic and Arctic water masses. During the Arctic field season August 2002, surface temperature, salinity, density, and phytoplankton biomass (chi a) was measured in Kongsfjorden. A total of 15 surface samples were collected for the phytoplankton related measurements. Chl a values ranged from 0.08 to 1.4mg chi a $m^{-3}$ (mean of 0.53mg chl a $m^{-3}$) in the overall surface stations. The highest values of the chi a concentrations (> 1.0mg chi a $m^{-3}$) were found near glacier in the northeastern part of Kongsfjorden. Nanoplanktonic (< $20{\mu}m$) phytoflagellates were important contributors for the increase of the chi a. The nano-sized phytoflagellates accounted for more than 90% of the total chi a biomass in the study area. Surface temperatures and salinities ranged from 2.5 to $7.18^{\circ}C$ (mean of $4.65^{\circ}C$) and from 22.55 to 32.97 psu (mean of 30.16 psu), respectively. The physical factors were not highly correlated with phytoplankton distribution. The character of surface water due to down-fjord wind was highly similar to phytoplankton distribution. Drifting ice, freshwater, and semdiment inputs from large tidal glaciers located in the inner part of Konsfjorden create steep physico- and biogeochemical environmental gradients along the length of this ford. The glacial inputs cause reduced biodiversity biomass and productivity in the pelagic community in the inner fjord. Primary production of benthic and pelagic microalgae is reduced due to the limited light levels in the turbid and mixed inner waters. The magnitude of glacial effects diminishes towards the outer fjord. Kongsfjorden is an important feeding ground fer marine mammals and seabirds. Especially, seabirds play the largest energy intake and also export nutrients for primary production of the marine microalgae. Kongsfjorden has received a lot of research attention as a site for exploring the impacts of climate changes. Dasan Station in Kongsfjorden will be an important Arctic site for monitoring and detecting future environmental changes.

Further Applications of Molecular Orbital Calculations for Solid HF According to Pseudolattic Method

  • Kim, Jin-Seog;No, Kyoung-Tai;Jhon, Mu-Shik
    • Bulletin of the Korean Chemical Society
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    • v.5 no.2
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    • pp.61-64
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    • 1984
  • The molecular orbital calculations for solid HF are performed by using the pseudolattice method considering the coulomb lattice sum. In order to obtain the reliable net atomic charges and lattice energy of one dimensional chains, the limited counting of interactions terms up to second neighbours for zig-zag chain and third neighbours for linear chain are sufficient in this calculation. In three dimensional solid HF, the contribution of interaction energy between non-hydrogen bonded neighbours to lattice energy is about 3.5% and the lattice energy of nonpolar structure is stablized by 2.05 kcal/mole compared with that of polar structure. And, this method is further tested and compared with the other methods.

Mechanical Properties of Acrylonitrile Functionalized Emulsion SBR/silica Compounds (아크릴로니트릴이 극성기로 도입된 유화중합 SBR/실리카 컴파운드의 기계적 물성)

  • Kim, Dong-Won;Seo, Byeong-Ho;Kim, Hee-Jeong;Paik, Hyun-Jong;Kang, Jong-Won;Kim, Won-Ho
    • Elastomers and Composites
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    • v.47 no.1
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    • pp.54-64
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    • 2012
  • Acrylonitrile was introduced in the emulsion SBR to increase compatibility between silica and rubber. AN-SBR/silica compounds showed faster vulcanization time and higher delta torque values than SBR 1721/silica compounds because interaction between nitrile group of AN-SBR and silanol group on the silica surface could make hydrogen bond that prevented adsorption of the accelerator on the silica surface, which improved the vulcanization reaction efficiency and enhanced the degree of crosslinking. AN-SBR/silica compound showed higher values in minimum torque than SBR 1721/silica compound during the vulcanization because AN-SBR has higher molecular weight than SBR 1721 in the raw material. When PEG was added to the SBR 1721 and AN-SBR compounds, vulcanization time was faster than SBR 1721 and AN-SBR compounds without PEG because PEG has a large number of ether linkages which show high compatibility with silanol group on the silica surface that prevented the adsorption of the accelerator and the ingredients on the silica surface, which improved the vulcanization reaction efficiency. In the mechanical properties, AN-SBR compounds showed higher modulus values at 100%, 300% than SBR 1721 compounds because interaction between nitrile group of AN-SBR and silanol group on the silica surface enhanced the degree of crosslinking. In the dynamic properties, AN-SBR compounds showed lower tan ${\delta}$ values at $0^{\circ}C$ than SBR 1721 compounds in accordance with the $T_g$ values. AN-SBR compounds showed lower tan ${\delta}$ values at $60^{\circ}C$ than SBR 1721 compounds because interaction between acrylonitrile and silica caused strong filler-rubber interaction that induced low energy dissipation by the filler-filler interaction.