• Title/Summary/Keyword: ${\omega}-3$

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Mapping of Underground Geological Boundaries overlain by Conductive Overburden: Application of TEM Soundings (TEM 탐사에 의한 간척지내 전도성 표층 하부 지질 구성 파악)

  • Hwang, Hak-Soo;Moon, Sang-Ho
    • The Journal of Engineering Geology
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    • v.21 no.3
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    • pp.213-219
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    • 2011
  • Transient/time-domain electromagnetic (TEM) soundings were carried out on reclaimed land, since the TEM sounding has good resolution of a conductive and thin overburden. The reclamation material is marine clay dredged from the seafloor, which is currently undergoing consolidation in the upper part of the dredged layer. The conductivity of the marine-origin clay is generally more than 0.3 S/m. The aim of the TEM sounding was to determine the depths of weathered and soft rocks overlain by thick and conductive overburden. The TEM responses were measured at delay times of 0.050-20.575 ms with a $30{\times}30$ m coincident loop array. Data from the TEM inversion and core logging indicate that the resistivities of the conductive overburden are less than 2 ${\Omega}$-m, while those of the weathered and soft rocks are 10-20 and 70 ${\Omega}$-m, respectively. The depth to weathered rock is 26-58 m and the depth to soft rock is 46-75 m.

Mechanical Evaluation of Posterior Dynamic Omega-wire Stabilization System (후방 요추 극돌기간 유동적 오메가형 스프링 고정재의 역학적 평가)

  • Lee, Yeon-Soo;Song, Geun-Soo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.36 no.11
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    • pp.1099-1104
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    • 2012
  • The study investigates the mechanical deformation of a newly developed screwless omega-wire dynamic system for stabilization of the spine. The omega-wire spring stabilization system was tested under tension, compression, and dynamic compressive fatigue loads. In addition, its bending deformation was compared to that of a spiral-wire spring system using FEA. A model whose hanger inter-center distance is 60 mm showed an ultimate tensile stress of 3981.7 N at a displacement of 3.61 mm and an ultimate compressive load of 535.6 N at a displacement of 2.16 mm. Under fatigue loading of 5 Hz with 10 N/1 N, it did not show any failure over 5 million cycles, and the displacement was restricted to 8-9 mm. In the FEA, the omega-wire spring system showed more flexible bending features than did the spiral-wire spring system.

Quantitative analysis of anthraquinones in Polygonum multiflorum Thunberg (하수오(何首烏)의 안트라퀴논 함량분석)

  • Lee, Hye-Won;Park, So-Young;Choo, Byung-Kil;Chae, Sung-Wook;Lee, A-Yeong;Kim, Ho-Kyoung
    • Korean Journal of Oriental Medicine
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    • v.13 no.3
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    • pp.157-163
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    • 2007
  • Objective: Polygonum multiflorum Thunberg (Polygonaceae) has been traditionally used as a tonic and the purgative in China and Korea. The genus Polygonum is a source of a wide range of phenolic compound, flavanoids, anthraquinones, stilbenes and tannins. In this study, three anthraquinones were isolated and quantitative determination of anthraquinones from P multiflorum has been developed for quality standardization. Methods : Three anthraquinone derivatives were isolated from a methanol extract of the radix of P. multiflorum by the chromatographic separation. Their structures were identified as emodin, physcion and ${\omega}$-hydroxyemodin on the basis of spectral data (MS, lH-NMR, 13C-NMR) and chemical analysis. HPLC analysis was performed to determine the contents of emodin, physcion, chrysophanol, rhein and ${\omega}$-hydroxyemodin in P. multiflorum from different specimens were collected from twenty Korean markets. Results: According to the results, the contents of emodin, physcion, chrysophanol, rhein and ${\omega}$-hydroxyemodin were 0.145%, 0.434%, 0.016%, 0.026%, 0.030% by HPLC, respectively. Conclusions : In these results, we have determined the contents of emodin, physcion, chrysophanol, rhein and ${\omega}$-hydroxyemodin in P. multiflorum, respectively. We hope that this study will contribute to the standardization and quality control of herbal medicine.

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Segmental Bioelectrical Impedance Analysis(SBIA) for Determining Body Composition (부위별 생체 전기 임피던스법을 이용한 체성분 분석에 관한 연구)

  • 차기철;손정민;김기진;최승훈
    • Korean Journal of Community Nutrition
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    • v.2 no.2
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    • pp.179-186
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    • 1997
  • A new bioelectrical impedance method has been developed and evaluated. The electrodes; were made of stainless steel and electrical interfaces were created by an upright subject gripping hand electrodes and stepping onto foot electrodes. Eight tactile electrodes were in contact with surfaces of both hands and feet; thumb, palm and fingers, front sole, and rear sole. Automatic on-off switches were used to change current pathways and to measure voltage differences for target segments. Segmental body resistances and whole body resistance(RWHOLE)were measured in 60 healthy subjects. Segmental resistances of right arm(RRA), left arm(RLA), trunk(RT), right leg(RRL) and left leg(RLL)were310.0$\pm$61.6$\Omega$, 316.9$\pm$64.6$\Omega$, 25.1$\pm$3.4$\Omega$, 236.8$\pm$31.2$\Omega$ and 237.6$\pm$30.4$\Omega$, respectively. Individual segmental impedance indexes(Ht2/RRA, Ht2/RT, and Ht2 /RLA) were closely related to lean body mass(LBM)as measured by densitometry ranged from r=0.925 to 0.960. Ht2/(RRA+RT+RLA) predicted LBM slightly better(r=0.969) than the traditional index, Ht2/RWHOLE(r=0.964), supporting the accuracy of the segmental measurement. A multiple regression equation utilizing Ht2/RRA, Ht2/RT and Ht2/RRL predicted LBM with r=0.971. Ht2/RRA term of the regression contributed to more than 40$\%$ of the LBM prediction, indicating that lean mass of arm represented whole body LBM more closely than other body segments. The new bioimpedance method was characterized by upright posture, eight tactile electrodes, segmental measurements and utilization of electronic switches in comparison with the traditional method. The measurement with this new method was extremely reproducible, quick and easy to use.

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헬리콘 플라즈마의 연구 현황

  • 엄세훈;장홍영
    • Proceedings of the Korean Vacuum Society Conference
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    • 2000.02a
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    • pp.183-183
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    • 2000
  • Aigrain에 의해 Helicon이라는 이름이 명명된 이후, helicon은 저온의 금속과 같은 높은 전도도(conductivity)를 갖는 매질이나 강한 자기장이 걸려있는 plasma를 전파해 나가는 저주파 전자기장을 지칭해왔다. 이온화된 개스에서 이러한 전자기장은 전자 공명 주파수(electron cyclotron frequency)와 이온 공명 주파수(ion cyclotron frequency) 사이의 주파수로 전파하며 전리층 (ionosphere)을 통과하며 발생하는 가청 주파수 영역대의 음조가 강하하는 현상에 의해 low-frequency whistler라고도 불린다. Helicon wave plasma는 Boswell에 의해 처음 발생된 후, 높은 이온화율(~100%)로 인해 많은 연구가 이루어져 왔다. 1985년에 Chen은 helicon plasma의 높은 이온화율을 설명하기 위해 Landaudamping을 제시하였다. 이러한 설명은 1997년에 Shamrai에 의해 TG mode가 도입되기 전까지 직접적인 실험결과 없이 helicon plasma 발생의 mechanism으로 받아들여졌다. shamrai의 이론에 의하면 정전기파(electrostatic wave)는 plasma의 표면(surface)에서 강하게 감쇄되어 energy를 전달하게 된다. Cho는 radial density 분포가 외각보다 중심이 높을 경우 TG wave의 power 전달이 중심에서 일어날 수 있음을 계산하였다. Helicon plasma의 특성은 높은 이온화율에 의한 높은 밀도($\geq$1012cm3), 1-2 kW의 rf power에서 상대적으로 낮은 전자 온도( 4eV), $\omega$ci $\omega$LH<$\omega$ $\omega$ce $\omega$pe 영역대의 주파수, 자기장 50-1200 Gauss, 압력 1-10 mTorr로 특정지을 수 있다. 이러한 외부분수들의 조건에 k라 helicon plasma는 여러 종류의 mode로 존재한다. Degeling은 이러한 mode의 변화를 capacitive mode, inductive mode, 그리고 helicon mode(wave mode)의 세가지 부분으로 구분하였다. Helicon plasma가 갖는 높은 이온화율은 여러 가지 응용으로의 가능성을 가지고 있다. 그 예로 plasma processing, plasma wave에 의한 입자 가속, 그리고 가스 레이저 활성 매질 발생 등이 있다. 특히 plasma processing의 경우 helicon plasma는 높은 밀도, 비교적 낮은 자기장, remote operation 등이 가능하다는 점에서 현재 연구가 활발히 진행되고 있다. 상업용으로도 PMT와 Lucas Signatone Corp.에 서 helicon source가 제작되었다. 또한 높은 해리율을 이용하여 저유전 물질인 SiOF의 증착에서 적용되고 있다. 이 외에도 다수의 연구결과들이 발표되었다.

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Comparative Studies on Immobilized Invertase on Sepharose and Phenoxyacetyl Cellulose (Sepharose와 Phenoxyacetyl Cellulose에 고정화 시킨 Invertase에 관한 비교 연구)

  • Choi, Choon-Soon;Jeon, Moon-Jin;Byun, Si-Myung
    • Korean Journal of Food Science and Technology
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    • v.12 no.3
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    • pp.176-181
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    • 1980
  • Yeast invertase was immobilized on the 2 kinds of matrices : one is an indirectly coupled enzyme to the cyanogen bromide activated Sepharose by using ${\omega}-aminohexyl$ group as an extension arm, and the other is a tightly adsorbed enzyme on the modified hydrophobic cellulose derivative which has a phenoxyacetyl group as a linkage. The enzyme preparation coupled on Sepharose retained 26.0% of the original activity against sucrose as a substrate, while the preparation immobilized on phenoxyacetyl cellulose retained 72.9% . The immobilized invertase preparation on ${\omega}-aminohexyl$ Sepharose showed the optimal pH 4.5, optimal temperature $60^{\circ}C$, activation energy $5,941\;cal/mole{\cdot}deg$ and Km' 22.2 mM against sucrose, while the preparation adsorbed on phenoxyacetyl cellulose showed the optimal pH 4.0, optimal temperature $60^{\circ}C$, activation energy $7,769\;cal/mole{\cdot}deg$ and Km' 69.9 mM.

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Biotransformation of Dehydroparadols by Aspergillus niger

  • Lee, Sang-Sup;Lee, Woo-Young
    • Archives of Pharmacal Research
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    • v.18 no.6
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    • pp.458-461
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    • 1995
  • +To prove uniqueness of allylic alcohol formation from ${\alpha},{\beta}-unsaturated$ ketones by mammal enzymes, a metabolic pattern of dehydroparadols, non-pungent synthetic analogs of shogaol by Aspergillus niger was examined. Two biotransformation products of a dehydroparadol, 1-(4hydroxy-3-methoxyphenyl)-non-1-en-3-one were accumulated in the culture broth of A. niger. They were characterized as 1-(4-hydroxy-3-methoxyphenyl)-non-1-en-9-01-3-one and 1-(4-hydroxy-3-methoxyphenyl)-nonan-9-o1-3-one by UV, NMR and mass spectroscopic analyses. Accumulation of allylic alcohol metabolites was not observed.

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IMPROVED MULTIPLICITY RESULTS FOR FULLY NONLINEAR PARABOLIC SYSTEMS

  • Jung, Tacksun;Choi, Q-Heung
    • Korean Journal of Mathematics
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    • v.17 no.3
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    • pp.283-291
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    • 2009
  • We investigate the existence of multiple solutions (${\xi},{\eta}$) for perturbations of the parabolic system with Dirichlet boundary condition $$(0.1)\;\begin{array}{lcr}{\xi}_t=-L{\xi}+g_1(3{\xi}+{\eta})-s{\phi}_1-h_1(x,t)\;in\;{\Omega}{\times}(0,\;2{\pi}),\\{\eta}_t=-L{\eta}+g_2(3{\xi}+{\eta})-s{\phi}_1-h_2(x,t)\;in\;{\Omega}{\times}(0,\;2{\pi}).\end{array}$$ We show the existence of multiple solutions (${\xi},{\eta}$) for perturbations of the parabolic system when the nonlinearity $g^{\prime}_1,\;g^{\prime}_2$ are bounded and $3g^{\prime}_1(-{\infty})+g^{\prime}_2(-{\infty})<{\lambda}_1,\;{\lambda}_n<3g^{\prime}_1(+{\infty})+g^{\prime}_2(+{\infty})<{\lambda}_{n+1}$.

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Synthesis of ITO Nano-Particles by SAS Method and Preparation for Conductive PET Film with Multi-Layers (SAS법을 이용한 ITO 나노입자의 합성과 적층 도포된 PET 도전필름의 제조)

  • Yun, Sang-Ho;Kim, Moon-Sun;Lee, Hee-Dai;Kim, Chul Kyung
    • Applied Chemistry for Engineering
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    • v.19 no.1
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    • pp.37-44
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    • 2008
  • The multi-layer PET film of ITO/ATO was prepared by a wet coating method to obtain the transparent film with a high conductance at low cost. ITO nano-particles were synthesized by a SAS method at 15 MPa and $50^{\circ}C$, where optimized rate of In/Sn was 65. Average diameter and resistivity of ITO obtained from SAS are $15{\pm}2nm$ and $4{\times}10^4{\Omega}{\cdot}cm$. Coating solution was prepared at pH 10. Roughness (Ra), resistivity, and transmissivity of ATO film on PET are 9 nm, $5.5{\times}10^6{\Omega}{\cdot}cm$, and 91%. The multi-layered film of ITO/ATO was obtained by solution including 0.1, 0.5, 1.0, and 2.0 ITO wt% on ATO layer. Roughness (Ra) of multi-layered film with 0.1, 0.5, 1.0, and 2.0 ITO wt% is 4, 10, 12, and 16 nm, respectively. Corresponding resistivity with an increasing ITO concentration is $3.7{\times}10^6$, $2.4{\times}10^6$, $8{\times}10^5$, and $2{\times}10^5{\Omega}{\cdot}cm$. Transmissivity of ITO/ATO film decreases as 89, 88, 86, and 82% with an increasing ITO concentration as 0.1, 0.5, 1.0, and 2.0 wt%.

Effect of External Resistance on Electrical Properties of Two-Chamber type Microbial Fuel Cells (이형반응기 미생물연료전지의 전기적 특성에 미치는 외부저항의 영향)

  • Lee, Myoung-Eun;Jo, Se-Yeon;Chung, Jae-Woo;Song, Young-Chae;Woo, Jung-Hui;Yoo, Kyu-Seon;Lee, Chae-Young
    • Journal of Korean Society of Environmental Engineers
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    • v.33 no.3
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    • pp.167-173
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    • 2011
  • The Effects of external resistance on electrical properties such as current density, power density and coulombic efficiency were investigated in two-chamber type MFCs using a ferricyanide as reducing agent. A stable electricity was produced when a constant time elapsed after innoculation of mixed cultures into the anode compartment; voltages from 0.13 to 0.16 V was measured at $50{\Omega}$ of external resistance. When the external resistance was increased, the current density decreased and the power density rapidly increased and then slowly decreased. Big variation of electrical properties was observed in high-current density region due to the concentration loss related with substrate consumption in repeated experiments changing the external resistance. The maximum power density ($175.8mW/m^2$) and coulombic efficiency (46.1%) were obtained at $100{\Omega}$ of the external resistance which is nearest with the internal resistance ($134{\Omega}$) of MFC system.