• 제목/요약/키워드: KOH activation

검색결과 216건 처리시간 0.031초

고분자 전구체로부터 합성된 활성탄소를 이용한 암모니아 흡착 (Ammonia Adsorption of Activated Carbons Synthesized from Polymeric Precursor)

  • Jung, Woo-Young;Park, Soo-Jin;Pak, Pyong-Ki
    • 한국섬유공학회:학술대회논문집
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    • 한국섬유공학회 2003년도 봄 학술발표회 논문집
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    • pp.311-312
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    • 2003
  • Activated carbons (ACs) are widely used in adsorption for the removal of gaseous and aqueous pollutants[1]. Although a wide range of carbonaceous materials can be converted into ACs, the coal and lingocellulosic materials are the most commonly used starting materials for the production of commercial ACs. Recently, there are a quite large number of studies regarding the preparation of ACs from various polymeric materials because of high carbon yield and low ash content In this work, ACs are prepared from polystyrene (PS) by chemical activation with potassium hydroxide and the effect of the KOH-to-PS ratio to adsorption of ammonia is investigated. (omitted)

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PVdF-PVP 복합결합제를 이용한 EDLC의 성능과 안정성 (Performance and Safety of EDLC of PVdF-PVP Mixed Binder)

  • 김경민;오호성;정세일;이용욱;강안수
    • 대한안전경영과학회:학술대회논문집
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    • 대한안전경영과학회 2001년도 춘계학술대회
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    • pp.319-324
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    • 2001
  • High surface area and high pore volume activated carbon was prepared by KOH activation of rice hull. The electrodes were fabricated by compounding the commercial and rice hull activated carbons with PVdF and PVdF-PVP mixed binders without addition of conductivity improver. The electrodes fabricated with rice hull activated carbon and PVdF-PVP mixed binders showed the best performance because the PVP played as a pore-forming agent. The electrode exhibited excellent electrochemical characteristics having 7.9 W.h/kg of energy density, 33.5 F/g of speific capacitance, 0.7 $\Omega$ of ESR and good efficiency of self-discharge compared with that fabricated with commercial activated carbons.

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Osteoclast-derived SLIT3 is a coupling factor linking bone resorption to bone formation

  • Koh, Jung-Min
    • BMB Reports
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    • 제51권6호
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    • pp.263-264
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    • 2018
  • We identified osteoclast-derived SLIT3 as a new coupling factor using fractionated secretomics. Coupling links bone resorption to bone formation. SLIT3 stimulated the recruitment and proliferation of osteoblasts into bone remodeling sites via activation of ${\beta}-catenin$. Autocrine signaling by SLIT3 also inhibited bone resorption by suppressing the fusion and differentiation of pre-osteoclasts. All mice lacking Slit3 or its receptor Robo1 showed an osteopenic phenotype with low bone formation and high bone resorption. A small truncated recombinant SLIT3 protein increased bone mass in an osteopenic mouse model. These results suggest that SLIT3 is a novel therapeutic target in metabolic bone diseases.

Kinetics and Mechanism of the Pyridinolysis of Aryl Cyclobutanecarboxylates in Acetonitrile

  • koh, Han-Joong;Han, Kwang-Lae;Lee, Hai-Whang;Lee, Ik-Choon
    • Bulletin of the Korean Chemical Society
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    • 제23권5호
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    • pp.715-720
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    • 2002
  • Kinetic studies of the reaction of Z-aryl cyclobutanecarboxylates with X-pyridines in acetonitrile at $55.0^{\circ}C$ have been carried out. The reaction proceeds by a stepwise mechanism in which the rate-determining step is the breakdown of the zwitterion ic tetrahedral intermediate, T $\pm$ . These mechanistic conclusions are drawn based on (i) the large magnitude of ${\rho}X$ and $\rhoZ$, (ⅱ) the positive sign of ${\rho}XZ$ and the larger magnitude of $\rhoXZ$ than normal SN2 processes, (ⅲ) a small positive enthalpy of activation, ${\Delta}H{\neq}$, and a large negative, ${\Delta}S{\neq}$, and lastly (iv) adherence to the reactivity-selectivity principle (RSP) in all cases.

열처리로불소화 및 활성화된 탄소나노튜브의 NO 가스센서 특성 (NO gas sensing properties of modified multi wall carbon nanotubes (MWCNTs) by thermal fluorination and activation)

  • 김민일;박미선;이세현;이영석
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2015년도 제46회 하계학술대회
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    • pp.1543-1543
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    • 2015
  • 반도체식 가스센서의 한계를 극복하기 위하여 열불소화 방법과 활성화 방법을 이용하여 NO 가스 감지용 가스센서를 제조하였으며, 각각의 특성을 평가하였다. 열불소화 처리된 탄소나노튜브는 열처리 온도에 따라 반도체적 성질이 p-type에서 n-type으로 변화한 후 다시 p-type으로 변화하였으며, 활성화 처리된 탄소나노튜브는 비표면적이 증가할수록 NO 감지에 따른 저항변화가 증가하였다. 저항변화율은 $200^{\circ}C$에서 불소화 처리된 탄소나노튜브가 가장 크게 나탔으나 응답시간을 고려할 경우 $600^{\circ}C$에서 불소화 및 6M의 KOH를 이용한 경우 가장 우수한 특성을 보였다.

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플라이애쉬와 메타카올린을 사용한 무기결합재의 개발 (Development of the inorganic which uses the Fly-ash and Meta-kaolin)

  • 정석조;추용식;이종규
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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    • pp.433-436
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    • 2005
  • The Fly-ash makes an Alumino-silicate gel when it mixes an alkali or a silicate solution. This Alumino-silicate gel is produced to the activation of an alkali silicate. And this act to the binder and makes a combine of particles. This study involved mechanical strengths of an Alumino-silicate Gel based the Fly-ash with an alkali solution. NaOH, KOH were utilized to an alkali solution. The alkali solution concentration was varied from 6 to 12M and the some added also the Meta-kaolin, Waterglass so that it made high the mechanical performance. Based on the experimental result, the compressive strengths increased as the quantity of the Meta-kaolin increased. And a mechanical strengths appeared according to the concentration of an alkali solution so that it was different. XRD, FT-IR have been used to characterize mechanical performance.

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Kinetics and Mechanism of the Pyridinolysis of Aryl Cyclopropanecarboxylates in Acetonitrile

  • Koh, Han-Joong;Kang, Suk-Jin;Kim, Cheol-Ju;Lee, Hai-Whang;Lee, Ik-Choon
    • Bulletin of the Korean Chemical Society
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    • 제24권7호
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    • pp.925-930
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    • 2003
  • Kinetic studies of the reaction of Z-aryl cyclopropanecarboxylates with X-pyridines in acetonitrile at 55.0 ℃ have been carried out. The reaction proceeds by a stepwise mechanism in which the rate-determining step is the breakdown of the zwitterionic tetrahedral intermediate, $T^{\pm}$. These mechanistic conclusions are drawn base on (i) the large magnitude of ρx and ρz, (ii) the positive sign of ρxz and the larger magnitude of ρxz than normal $S_N2$ processes, (iii) a small positive enthalpy of activation, Δ$H^≠$, and a large negative, Δ$S^≠$, and lastly (iv) adherence to the reactivity-selectivity principle (RSP) in all cases.

Poly(3,4-ethylenedioxythiophene) Electrodes Doped with Anionic Metalloporphyrins

  • 송의환;여인형;백운기
    • Bulletin of the Korean Chemical Society
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    • 제20권11호
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    • pp.1303-1308
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    • 1999
  • Conducting poly(3,4-ethylenedioxythiophene) (PEDT) films with metalloporphyrins incorporated as the counter ions were prepared by electropolymerization of the monomer in the presence of metal-tetra(sulfonatophenyl) porphyrin anions. Cathodic reduction of oxygen on the resulting conducting polymer films was studied. The overpotential for O2 reduction on electrodes with cobalt-porphyrin complex was significantly smaller in acidic solutions than on gold. In basic solutions, the overpotential at low current densities was close to those on platinum and gold. Polymer electrode with Co-complex yielded higher limiting currents than with Fe-complex, although the Co-complex polymer electrode was a poorer electrocatalyst for O2 reduction in the activation range of potential than the Fe counterpart. From the rotating ring-disk electrode experiments, oxygen reduction was shown to proceed through either a 4-electron pathway or a 2-electron pathway. In contrast to the polypyr-role-based electrodes, the PEDT-based metalloporphyrin electrodes were stable with wider potential windows, including the oxygen reduction potential. Their electrocatalytic properties were maintained at temperatures up to 80℃ in KOH solutions.

Pharmacology of novel vanilloid receptor antagonists

  • Park, Jin-Kyu;Yi, Jung-Bum;Koh, Hyun-Ju;Jeong, Yeon-Su;Lim, Kyung-Min;Moh, Joo-Hyun;Suh, Young-Ger;Oh, Uh-Taek;Kim, Hee-Doo;Park, Hyeung-Geun;Park, Young-Ho
    • 대한약학회:학술대회논문집
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    • 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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    • pp.251.1-251.1
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    • 2002
  • Capsaicin and analogues are valuable analgesic agents when administered to mammals. including humans. However. their pungency. hypothermia and the effects on the cardiovascular and respiratory systems through their general activation of primary afferents severely limit their use. So competitive antagonists have been pursued as a novel pharmacological agent for analgesics. rather than agonists. We have identified a new class of potent and selective vanilloid receptor (VR) antagonists. (omitted)

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Role of metabolism by flavin-containing monooxygenase in thioacetamide-induced immunosuppression

  • Lee, Jeong W.;Ki D. Shin;Shin W. Cha;Kim, Jong-C.;Kim, Eun J.;Sang S. Han;Tae C. Jeong;Woo S. Koh
    • 한국독성학회:학술대회논문집
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    • 한국독성학회 2001년도 International Symposium on Signal transduction in Toxicology
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    • pp.121-121
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    • 2001
  • Thioacetamide has been known to cause immune suppression. In this report we studied the role of metabolic activation by flavin-containing monooxygenase in the thioacetamide-induced immune response. To determine whether the metabolites of thioacetamide produced by flavin-containing monooxygenase result in the immunosuppression, methimazole, a flavin-containing monooxygenase inhibitor, was used to block the flavin-containing monooxygenase pathway.(omitted)

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