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A Study on the PP/PS Blends with Nylon 6 Reactive Compatibilizers (Nylon6계 반응 상용화제에 의한 PP/PS 블렌드에 관한 연구)

  • 서성식;이기윤;김성희;김동철;이승구
    • Polymer(Korea)
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    • v.26 no.1
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    • pp.71-79
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    • 2002
  • RPP(maleic-anhydride grafted PP)and OPS(oxazoline grafted PS) do not react to each other, and thus show immiscibility. In this study, Nylons was added to RPP/OPS blend systems, as a reactive compatibilizer for enhancing the miscibility of the blends. When Nylon6 was added to the blends of RPP and OPS, RPP/Nylon6/OPS was produced. The effects of the molar ratio of Nylon6 on the RPP-Nylon6-OPS reaction were studied. Torque test and FT-IR analysis have been carried out to investigate the reaction of RPP/Nylon6/OPS system. The reaction torgue ratio and reaction efficiency show the maximum values at 1 : 0.66 : 1 and 1 : 1 : 1 (in moles) for RPP/Nylon6/OPS. In the RPP/Nylon6/OPS blends, their mechanical properties were changed with the molar ratio of Nylon6 and showed the highest value at molar ratio of 1.5. Physical properties and compatibility of RPP/Nylon6/OPS were compared with those of PP/Nylon6/OPS. Consequently, RPP/Nylon6/OPS plays a proper role as a reactive compatibilizer to the PP/PS blend system.

부성기체 $SF_6$Gas의 방전특성과 고기압 $SF_6$Gas중에서의 impulse corona에 관한 소고

  • 서국철
    • 전기의세계
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    • v.25 no.6
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    • pp.45-48
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    • 1976
  • 과거 수십년간 전력계통의 절연에 쓰여 온 공기에 대치하여 근년 고기압 SF$_{6}$gas에 의한 gas절연 방식이 급속도로 진전되고 있으며 거기에 수반하여 SF$_{6}$gas의 방전특성 해명이 초고압 장 gap영역에서 급선무로 되어 있다. 또한 초고압송전에 대응하는 각종 전력기기 cable등의 고기압 절연이 실용화 하게 되었으며 신뢰도가 높고 합리적인 gas 절연기기의 설계를 목표로 부성기체 특히 고기압 SF$_{6}$gas의 절연파괴 특성의 연구가 진행되고 있다. 고기압 SF$_{6}$gas는 높은 파괴 전체를 가지므로 극히 적은 원인으로도 절연 특성에 영향을 미치며 공기, 질소등 기체와는 매우 다른 방전 특성을 나타낸다. 여기서는 SF$_{6}$gas의 특이한 방전 특성과 고기압 SF$_{6}$gas 중에서의 impulse corona의 특성을 고찰하려고 한다.

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Evaluation of the Neural Fiber Tractography Associated with Aging in the Normal Corpus Callosum Using the Diffusion Tensor Imaging (DTI) (확산텐서영상(Diffusion Tensor Imaging)을 이용한 정상 뇌량에서의 연령대별 신경섬유로의 변화)

  • Im, In-Chul;Goo, Eun-Hoe;Lee, Jae-Seung
    • Journal of the Korean Society of Radiology
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    • v.5 no.4
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    • pp.189-194
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    • 2011
  • This study used magnetic resonance diffusion tensor imaging (DTI) to quantitatively analyze the neural fiber tractography according to the age of normal corpus callosum and to evaluate of usefulness. The research was intended for the applicants of 60 persons that was in a good state of health with not brain or other disease. The test parameters were TR: 6650 ms, TE: 66 ms, FA: $90^{\circ}$, NEX: 2, thickness: 2 mm, no gap, FOV: 220 mm, b-value: $800s/mm^2$, sense factor: 2, acquisition matrix size: $2{\times}2{\times}2mm^3$, and the test time was 3 minutes 46 seconds. The evaluation method was constructed the color-cored FA map include to the skull vertex from the skull base in scan range. We set up the five ROI of corpus callosum of genu, anterior-mid body, posterior-mid body, isthmus, and splenium, tracking, respectively, and to quantitatively measured the length of neural fiber. As a result, the length of neural fiber, for the corpus callosum of genu was 20's: $61.8{\pm}6.8$, 30's: $63.9{\pm}3.8$, 40's: $65.5{\pm}6.4$, 50's: $57.8{\pm}6.0$, 60's: $58.9{\pm}4.5$, more than 70's: $54.1{\pm}8.1mm$, for the anterior-mid body was 20's: $54.8{\pm}8.8$, 30's: $58.5{\pm}7.9$, 40's: $54.8{\pm}7.8$, 50's: $56.1{\pm}10.2$, 60's: $48.5{\pm}6.2$, more than 70's: $48.6{\pm}8.3mm$, for the posterior-mid body was 20's: $72.7{\pm}9.1$, 30's: $61.6{\pm}9.1$, 40's: $60.9{\pm}10.5$, 50's: $61.4{\pm}11.7$, 60's: $54.9{\pm}10.0$, more than 70's: $53.1{\pm}10.5mm$, for the isthmus was 20's: $71.5{\pm}17.4$, 30's: $74.1{\pm}14.9$, 40's: $73.6{\pm}14.2$, 50's: $66.3{\pm}12.9$, 60's: $56.5{\pm}11.2$, more than 70's: $56.8{\pm}11.3mm$, and for the splenium was 20's: $82.6{\pm}6.8$, 30's: $86.9{\pm}6.4$, 40's: $83.1{\pm}7.1$, 50's: $81.5{\pm}7.4$, 60's: $78.6{\pm}6.0$, more than 70's: $80.55{\pm}8.6mm$. The length of neural fiber for normal corpus callosum were statistically significant in the genu(P=0.001), posterior-mid body(P=0.009), and istumus(P=0.012) of corpus callosum. In order of age, the length of neural fiber increased from 30s to 40s, as one grows older tended to decrease. For this reason, the nerve cells of brain could be confirmed through the neural fiber tractography to progress actively in middle age.

Fail-over Mechanisms based on Anycast for Stable IPv6 Recursive DNS Services (안정적인 IPv6 리커시브 DNS 서비스를 위한 애니캐스트 기반의 실패 복구 방안 연구)

  • Suh, Yu-Hwa;Kim, Kyung-Min;Shin, Yong-Tae;Song, Kwang-Ho;Kim, Weon;Park, Chan-Ki
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.2B
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    • pp.108-117
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    • 2007
  • Recursive DNS is configured as primary or secondary DNS on user PC and performs domain name resolution corresponding user's DNS query. At present, the amount of DNS traffic is occupied high rate in the total internet traffic and the internet traffic would be increased by failure of IPv6 DNS queries and responses as IPv6 transition environment. Also, existing Recursive DNS service mechanisms is unstable on malicious user's attack same as DoS/DDoS Attack and isn't provide to user trust DNS service fail-over. In this paper, we propose IPv6 Recursive DNS service mechanisms for based on anycast for improving stability. It is that fail-over Recursive DNS is configured IPv6 Anycast address for primary Recursive DNS's foil-over. this mechanisms increases reliability and resiliency to DoS/DDoS attacks and reduces query latency and helps minimize DNS traffic as inducing IPv6 address.

[$(3aR^*,6aS^*)$-6a-Hydroxy-Asymmetric Synthesis of cyclopenta[b]pyrrole-3a-carboxylate and Determination of Its Stereostructure via NMR Spectrum ($(3aR^*,6aS^*)$-6a-Hydroxy-cyclopenta[b]pyrrole-3a-carboxylate의 부제합성 및 NMR 스텍트럼을 통한 입체구조의 결정)

  • Kwon, Soon-Kyoung;Park, Myoung-Suk;Seo, Won-Jun
    • YAKHAK HOEJI
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    • v.38 no.5
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    • pp.544-554
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    • 1994
  • Pyrrolidine-2,3-dione derivative A was synthesized from oxalylation of chiral enamine Ba. The stereostructure of its major diastereomer $(A_{maj})$ was determined as octahydro-2,3-dioxo-6aS-hyd roxy-1-(1S-methoxycarbonyl-2-phenylethyl)-cyclopenta[b]pyrrole-3aR-carboxylic acid ethyl ester Aa by means of NMR spectrum. This result implied that the asymmetric carbon-carbon bond forming reaction occurred preferentially at the ${\beta}-face$ of Ba.

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A study of Frequency Distributions by the Action styles (작업환경에서 오는 시력분포 및 고찰)

  • Kang, Hyang Nyeo;Kim, Sung Tae
    • Journal of Korean Ophthalmic Optics Society
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    • v.5 no.2
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    • pp.99-105
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    • 2000
  • The classifying distribution by the action style was opticion 100, photoartist 100, college student 100 for the simple myopic 35%, for the simple myopic astigmatism 2%, for the compound myopic astigmatism 30.6% for the mixed astigmatism 62.6% for the compound hyperopic astigmatism 37.4% for the ratio of emmetropia 22.4% respectively. The retractive erroreye were -0.50~-2.00Dptr for the simple myopia 14%, -2.00~-6.00Dptr 16%, -6.00Dptr 5%, C-0.25(90.180)~C-2.00DptrAxis(90, 180) 2% for the simple myopicastigmatismS-0.25C-0.25DptrAxis(90, 180)~S-1.00C-1.00DptrAxis (90, 180) 22.6%, S-1.00C-1.00 DptrAxis (90, 180)~S-2.00C-2.00DptrAxis(90, 180) 8% for the compound myopic astigmatism. S+0.25C -0.25DptrAxis(90, 180)~S+2.00C-2.00DptrAxis(90,180) 6.2% for the mixed astigmatism. S+0.25C+0.25DptrAxis(90,180)~S+1.00C+1.00DptrAxis(90,180) 3.4%, S+1.00C+1.00DptrAxis(90,180)~S+2.00C+2.00DptrAxis(90,180) 0.34% for the compound hyperopic astigmatism.

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Shape Design Optimization of Disk Seal in $SF_6$ Gas Safety Valve ($SF_6$ 가스 안전밸브 디스크 시일의 최적설계에 관한 연구)

  • 김청균;조승현
    • Tribology and Lubricants
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    • v.20 no.5
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    • pp.231-236
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    • 2004
  • Sulfur Hexafluoride, S $F_{6}$ is widely used for leak detection and as a gaseous dielectric in transformers, condensers and circuit breakers. S $F_{6}$ gas is also effective as a cleanser in the semiconductor industry. This paper presents a numerical study of the sealing force of disk type seal in S $F_{6}$ gas safety valve. The sealing force on the disk seal is analyzed by the FEM method based on the Taguch's experimental design technique. Disk seals in S $F_{6}$ gas safety valve are designed with 9 design models based on 3 different contact length, compressive ratio and gas pressure. The calculated results of Cauchy stress and strain showed that the sealing characteristics of Teflon $^{ }$PTFE is more effective compared to that of FKM(Viton), which is related to the stiffness of the materials. And also, the contact length of the disk seal is important design parameter for sealing the S $F_{6}$ gas leakage in the safety valve.afety valve.

발효식품에서 분리된 젖산균으로 제조한 발효소시지의 특성

  • Park, U-Mun;Choe, Won-Hui
    • Bulletin of Food Technology
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    • v.10 no.1
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    • pp.102-114
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    • 1997
  • 발효식품에서 분리한 젖산균인 Lactobacillus plantarum(NFS #6-6과 S #3)의 발효소시지에서 starter culture로의 이용가능성을 알아보기 위하여 상업용 혼합 starter culture인 SL(Staphylococcus carnosus+ Lactobacillus pentosus)을 비교구로하여 발효소시지를 제조하고 그 특성을 상호 비교하였다. 발효 및 숙성 중 변화에서 starter culture의 종류에 관계없이 최종 43~45%의 수분이 증발되었다. PH는 SL 처리구가 가장 낮은 4.3 수준이었으며 수분활성도 역시 0.88로 SL 처리구가 가장 낮았다. 색도에서 적색도는 SL 처리구보다 NFS #6-6과 S #3 처리구가 더 높았으며 텍스쳐, 지방산, 그리고 유리아미노산의 변화에서 starter culture에 따른 차이점은 없었다. 관능평가시 색깔에서는 NFS #6-6 처리구가 SL 처리구에 비하여 낮았으나 향기, 맛, 텍스쳐와 기호도에있어서는 SL과 비슷한 결과를 나타내었다. 유산균수는 발효 2일째 급격히 증가하는 추세($10^8 cfu/g이상)였으나 S #3과 NFS #6-6이 더욱 빠른 성장을 보였으며 Step. aureus는 모든 처리구에서 검출되지 않았다. 장내세균의 경우 SL 처리구에 비하여 우수하여 S #3 처리구는 3일째, NFS #6-6 처리구는 8일째부터 검출되지 않았으며 Listeria 역시 SL처리구보다 우수한 억제력을 나타내었다.

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Preparation of CdS-pillared $H_4Nb_6O_7$ and Photochemical Reduction of Nitrate under Visible Light Irradiation

  • Tawkaew, Sittinun;Fujishiro, Yoshinobu;Uchida, Satoshi;Sato, Tsugio
    • The Korean Journal of Ceramics
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    • v.6 no.1
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    • pp.43-46
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    • 2000
  • $H_4Nb_6/O_{17}$/CdS nanocomposites which intercalated CdS particles, less than 0.8nm thickness, in the interlayer of $H_4Nb_6/O_{17}$ were prepared by the successive ion exchange reactions of $H_4Nb_6/O_{17}$ with $Cd^{2+}$ and $C_3H_7NH_3_+$, followed by the reaction with $H_2S$ gas. $H_4Nb_6/O_{17}$/CdS photocatalytically reduced $NO_3$ ̄ to $NO_2$ ̄ and $NH_3$in the presence of sacrificial hole acceptor such as methanol under visible light irradiation (wavelength>400nm), although unsupported CdS showed no noticeable photocatalytic activity for $NO_3$ ̄ reduction. The catalytic activity of $H_4Nb_6/O_{17}$/CdS greatly enhanced with co-doping of Pt particles in the interlayer.

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Effect of Molecular Weight of Chitosan on Flocculation of Suspended Solids in Rhodamine 6G-Sodium Dodecyl Sulfate System (키토산 분자량에 따른 Rhodamine 6G-Sodium Dodecyl Sulfate계의 응집효과에 관한 연구)

  • Kim, Sung Hyun;Nah, Jae Woon;Oh, Jeong Sun;Song, Ki Dong
    • Journal of the Korean Chemical Society
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    • v.42 no.6
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    • pp.672-678
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    • 1998
  • Chitin was extracted from crab shell of Portuns triberculatus and deacethylated to yield chitosan with various molecular weights. The absorption and the fluorescence spectra of Rhodamine 6G(Rh 6G)-sodium dodecyl sulfate(SDS) and Rh 6G-chitosan systems were obtained. From the spectra, we observed that the absorption and the fluorescence intensity of Rh 6G-SDS system decreased when S/D(the concentration of SDS to that of Rh 6G ratio) was below or at 32, while they increased when S/D was above 32. From the suspended solid(SS) removal rate and the transmittance of Rh 6G-SDS-chitosan system, we found that when S/D ratio was 32 its flocculating behaviour was much stronger than Rh 6G-SDS system. As the concentration and the molecular weight of chitosan increased, we also found that S/D range was extended from 32 to 100. With increasing the molecular weight of chitosan, the SS removal rate increased around pH 2~9 but decreased remarkably at pH>12.

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