• Title/Summary/Keyword: Activated energy

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Specific Capacitance Characteristics of Electric Double Layer Capacitors with Phenol Based Activated Carbon Fiber Electrodes and Aqueous Electrolytes (페놀계 활성탄소섬유 전극과 수용성 전해질을 사용하는 전기이중층 캐패시터의 비축전용량 특성)

  • Kim, Jong Huy;An, Kay Hyeok;Shin, Kyung Hee;Ryoo, Min Woong;Kim, Dong Kuk
    • Applied Chemistry for Engineering
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    • v.10 no.6
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    • pp.814-821
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    • 1999
  • The specific capacitance characteristics of the electric double layer capacitors(ELDC) which were made of phenol based activated carbon fiber(ACF) electrodes. Also the effect of aqueous electrolytes on the cell performance has been investigated with respect to different specific surface areas of electrodes and different kinds of aqueous electrolytes. It has been shown that larger surface area and pore size, higher conductivity of electrodes, and higher ion mobility of electrolytes have better specific capacitances. It has been found that heat treatment at $1200^{\circ}C$ and $CO_2$ post-activation at $900^{\circ}C$ of the electrode are effective to improve the specific capacitance over 145F/g and 165F/g, respectively. The EDLC showed high efficiency and long cycle life over 30000 cycles.

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A Study on the Thermal Adsorption and Desorption Characteristics of Industrial Odorants using Activated Carbon (활성탄을 이용한 산업체 악취물질의 열적 흡탈착 연구)

  • Kim, Joo Yeon;Rhee, Young Woo;Han, Mun Hee
    • Korean Chemical Engineering Research
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    • v.50 no.3
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    • pp.551-555
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    • 2012
  • Desorption reaction characteristics of the commercial activated carbons which were used for the removal of industrial odorants were investigated. BET specific surface area was analyzed to investigate the chemicophysical property of activated carbon. Adsorptivity of activated carbon was estimated by iodine number. Thermogravimetric analyzer (TGA) was used to investigate the desorption characteristics. Activation energies and reaction orders for reaction characteristics according to adsorption and desorption of activated carbons were estimated by employing the Friedman method and Freeman-Carroll method. Adsorptivity of reprocessed activated carbons were significantly lower than that of fresh activated carbons. In this study, it was found that the activation energies were 15.9~23.4 kJ/mol in Friedman method and 22.7~33.8 kJ/mol in Freeman-Carroll method.

Removal of Sulfur Compounds from Anaerobic Digestion Gas (혐기성 소화 가스로부터 황화합물의 제거)

  • Choi, Do-Young;Jang, Seong-Cheol;Ahn, Byoung-Sung;Choi, Dae-Ki
    • Applied Chemistry for Engineering
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    • v.19 no.1
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    • pp.31-36
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    • 2008
  • In hydrogen production for fuel cell by reforming ADG, sulfur compounds, odorant in ADG, are detrimental to reforming catalyst and fuel cell electrodes. We prepared alkali metal impregnated activated carbon to remove sulfur compounds in ADG by adsorption. The sulfur breakthrough adsorption capacity was changed depending on the oxygen concentration and relative humidity. Oxygen 0.2 vol% and RH 90% showed the highest sulfur breakthrough capacity. Adsorption characteristics of $H_2S$ on KI impregnated activated carbon were evaluated using dynamic adsorption method in a fixed bed. Based on the results, adsorption tower was designed and field-tested.

The Patent Analysis of Thermally Activated Delayed Fluorescence Materials (열 활성 지연 형광(TADF) 재료의 특허 분석)

  • Jo, Dae Seong;Sung, Min Jae;Kim, Min Ho;Choi, Seung Chul
    • Journal of the Semiconductor & Display Technology
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    • v.18 no.1
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    • pp.105-111
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    • 2019
  • The TADF (Thermally Activated Delayed Fluorescence)-based OLED patents were analyzed and 4410 of patents were selected at the first step. And 975 patents were screened at second step. Finally, 39 key patents were selected. Patent qualitative analysis was performed in these patents to find which of the four property (lifetime, efficiency, color purity, driving voltage) of TADF was improved. Also, the variation of the hosts and dopants in patented TADF material were surveyed and their combination was analyzed. According to the analysis of the variation and the combination, some of TADF compounds were used as an assistant dopant to transfer energy. In addition, it tended to transfer energy by forming exciplex that shows TADF characteristics. These were similar to the mechanism of the introduced hyper fluorescence and could solve the inherent TADF problems. Finally, patent citation network was illustrated to visualize the patent citations and citations relationship of the major applicants in the current TADF-based OLED technology. The leading patent applicant organization was revealed as Idemitsu Kosan, Semiconductor Energy Laboratory, UDC, Princeton University, Merck and Nippon Steel & Sumikin Chemical, which had lots of reference patents 559, 524, 477, 310, 258, and 167, respectively.

Evaluation of Properties and Fabrication of Tubular Supports Segmented-in-Series Solid Oxide Fuel Cell (SOFC) (세그먼트 SOFC 관형 세라믹 지지체의 제작 및 특성 평가)

  • Yun, Ui-Jin;Lee, Jong-Won;Lee, Seung-Bok;Lim, Tak-Hyoung;Park, Seok-Joo;Song, Rak-Hyun;Shin, Dong-Ryul;Han, Kyoo-Seung
    • Transactions of the Korean hydrogen and new energy society
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    • v.21 no.3
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    • pp.214-219
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    • 2010
  • In this study, we fabricated tubular ceramic support for segmented-in-series solid oxide fuel cell (SOFC) by using CSZ(CaO-stabilized $ZrO_2$) as main material and activated carbon as pore former. Thermal expansion properties of ceramic support with different amounts of activated carbon were analyzed by using dilatometer to decide a suitable sintering temperature. The tubular ceramic supports with different amounts of activated carbon (5, 10, 15wt.%) were fabricated by the extrusion technique. After sintering at $1100^{\circ}C$ and $1400^{\circ}C$ for 5h., cross section and surface morphology of tubular ceramic support were analyzed by using SEM image. Also, the porosity, mechanical property, gas permeability of tubular ceramic supports was measured. Based on these results, we established the suitable fabrication technique of tubular ceramic support for segmented-in-series SOFC.

Supercapacitors using Pure Single-walled Carbon Nanotubes

  • Tanaike, Osamu;Futaba, Don N.;Hata, Kenji;Hatori, Hiroaki
    • Carbon letters
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    • v.10 no.2
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    • pp.90-93
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    • 2009
  • The excellent and characteristic capacitor performance of pure single-walled carbon nanotubes (SWNTs), which differ from conventional activated carbon electrodes, is reported. SWNTs with little bundling showed higher specific capacitance than activated carbons. High operating voltage can be expected for pure SWNTs without metal contamination and graphene edge structure.

A Study on the Autoignition of Granulated Activated Carbon with Change of Oxygen Concentration (산소농도 변화에 따른 입상활성탄의 자연발화에 관한 연구)

  • 목연수;최재욱;류동현;최일곤;김상렬
    • Journal of the Korean Society of Safety
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    • v.10 no.2
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    • pp.84-91
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    • 1995
  • The characteristics of critical spontaneous ignition of granulated activated carbon were investigated In atmospheres of differing oxygen concentration. At the same concentration the larger vessels yielded the lower critical spontaneous ignition temperature. At the same vessel, as the concentration of oxygen was reduced, Ignition occurred later and at higher ambient temperature, and critical spontaneous ignition temperature increased. The apparent activation energy calculated from the Frank-Kamenetskii's ignition theory appeared to be the slight different value respectively and the mean apparent activation energy was 19850㎈/㏖.

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A method for properties evaluation of activated charcoal sorbents in iodine capture under dynamic conditions

  • Magomedbekov, Eldar P.;Obruchikov, Alexander V.
    • Nuclear Engineering and Technology
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    • v.51 no.2
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    • pp.641-645
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    • 2019
  • Experimental equipment for studying the sorption properties of iodine sorbents using radioactive methyliodide has been developed. The sorption capacity index ${\alpha}$ is proposed as a criterion parameter for assessing the quality of impregnated activated charcoals. It was found that this parameter does not depend on the dynamic conditions during the sorbent test. It was shown that values of the sorption capacity index allow to recommend iodine sorbents for industrial gas cleaning processes.