• Title/Summary/Keyword: Air Chemistry

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A New Species and Five New Records of Talaromyces (Eurotiales, Aspergillaceae) Belonging to Section Talaromyces in Korea

  • Thuong T. T. Nguyen;Hyang Burm Lee
    • Mycobiology
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    • v.51 no.5
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    • pp.320-332
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    • 2023
  • Talaromyces is a genus within the phylum Ascomycota (class Eurotiomycetes, order Eurotiales, family Trichocomaceae). Many species in this genus are known to produce diverse secondary metabolites with great potential for agricultural, medical, and pharmaceutical applications. During a survey on fungal diversity in the genus Talaromyces in Korea, six strains were isolated from soil, indoor air, and freshwater environments. Based on morphological, physiological, and multi-locus (ITS, BenA, CaM, and RPB2) phylogenetic analyses, we identified five previously unrecorded species in Korea (T. brevis, T. fusiformis, T. muroii, T. ruber, and T. soli) and a new species (T. echinulatus sp. nov.) belonging to section Talaromyces. Herein, detailed descriptions, illustrations, and phylogenetic tree are provided.

Effect of Cobalt Loading on the Performance and Stability of Oxygen Reduction and Evolution Reactions in Rechargeable Zinc-air Batteries

  • Sheraz Ahmed;Joongpyo Shim;Gyungse Park
    • Journal of the Korean Chemical Society
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    • v.68 no.2
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    • pp.87-92
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    • 2024
  • The commercialization of rechargeable metal-air batteries is extremely desirable but designing stable oxygen reduction reaction (ORR) catalysts with non-noble metal still has faced challenges to replace platinum-based catalysts. The nonnoble metal catalysts for ORR were prepared to improve the catalytic performance and stability by the thermal decomposition of ZIF-8 with optimum cobalt loading. The porous carbon was obtained by the calcination of ZIF-8 and different loading amounts of Co nanoparticles were anchored onto porous carbon forming a Co/PC catalyst. Co/PC composite shows a significant increase in the ORR value of current and stability (500 h) due to the good electronic conductive PCN support and optimum cobalt metal loading. The significantly improved catalytic performance is ascribed to the chemical structure, synergistic effects, porous carbon networks, and rich active sites. This method develops a new pathway for a highly active and advantageous catalyst for electrochemical devices.

A Numerical Study on the Combustion Characteristics for Stoker Type Incinerator with Various Injection Type of Secondary Air (2차 공기 주입방식에 따른 스토커형 소각로의 연소특성에 관한 수치해석적 연구)

  • Jung, Jin;Kim, Chang-Nyeong;Cho, Young-Min
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.10
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    • pp.835-842
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    • 2003
  • A three dimensional numerical analysis has been conducted for a stoker type incinerator which has the capacity of 1.5 ton/hr. The objective of the present study is to predict the effects of swirl induced by secondary air and to find an optimal operating condition of the incinerator. In this study, combustion characteristics such as distributions of temperature, velocity and concentration of each species have been examined with various injection types of secondary air and with different flow rates of secondary air in the incinerator. It is found that the secondary air injection on the combustion process makes the path of fluid particle longer in the combustor and enhances the mixing between air and combustion gas by arousing a swirl. Therefore, the injection type of secondary air can be an important key in the design process of incinerator.

Estimation of Fugitive Emission of Organic Hazardous Air Pollutants from Oil Refinery Industry (석유정제산업에서의 유기성 유해대기오염물질의 비산배출량 산정)

  • Yang, Sung-Bong;Yu, Mee-Seon;Lee, Young-Joon;Yoo, Eun-Jin;Choi, Sung-Hyun
    • Journal of Korean Society for Atmospheric Environment
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    • v.24 no.2
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    • pp.229-237
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    • 2008
  • Hazardous air pollutants emitted from the oil refinery plant were surveyed from 1993 US and 2005 Korean TRI data. Toluene, xylene, methanol, MTBE and n-hexane, relatively large in amount of fugitive emission, are considered as candidates of newly designated HAPs in Korea. The sealed oil pump, one of equipments among fugitive sources in the crude oil distillation tower was examined for the estimation of amounts of annual HAPs emissions according to several calculation methods using registered emission factors. Emission rates showed to be decreased with following calculation factors; average emission factor>pegged emission factor>concentration emission factor>correlation equation. Annual emission amounts of benzene, toluene, xylene. ethyl benzene and nhexane from the distillation tower were estimated and amounts of these HAPs calculated with TVOC concentrations obtained from LDAR program and correlation equations showed only 6% of those from using concentration factors.

Characterization of Spironaphthooxazine Derivative Thin Films for Optical Memory

  • Kang, Young-Soo;An, Sang-Do;Jang, Ju-Seog;Kim, Byung-Kyu;Kim, Yong-Joo
    • KIEE International Transactions on Electrophysics and Applications
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    • v.11C no.3
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    • pp.49-52
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    • 2001
  • The derivatives of spironaphthooxazine gause photoisomerization when they are illuminate with UV light. We investigated the photoisomerization of spironaphthooxazine derivatives for holographic memory. Langmuir-Blodgett (LB) films contain amphiphile spironaphthooxazine derivatives which can be applied in molecular devices by a change of molecular level energy and a refractive index. In order to investigate the photoisomerization of spironaphthooxazine derivatives at the air/water energy and a refractive index. In order to investigate the photoisomerization of spironaphthooxazine derivatives at the air/water interfaces, spironaphthooxazine derivatives with side alkyl chains were synthesized. The films of the spironaphthooxazine derivatives were characterized by the measurement of UV/vis spectroscopy, Brewster Angle Microscopy (BAM) and Atomic Force Microscopy (AFM). The monolayers of the spironaphthooxazine derivatives mixed with stearic acid were stable at the air/water interface and visualized by the measurement of BAM. The spironaphthooxazine derivative monolayers on the glass surface showed the maximum efficiency of diffraction as 0.99% by the measurement of holography.

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Detection of Volatile Alcohol Vapors Using Silicon Quantum Dots Based on Porous Silicon (다공성 실리콘을 근거한 실리콘 양자점을 이용한 휘발성 알콜 증기의 감지)

  • Cho, Bomin;Um, Sungyong;Jin, Sunghoon;Choi, Tae-Eun;Yang, Jinseok;Cho, Sungdong;Sohn, Honglae
    • Journal of Integrative Natural Science
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    • v.3 no.2
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    • pp.117-121
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    • 2010
  • Silicon quantum dots base on photoluminescent porous silicon were prepared from an electrochemical etching of n-type silicon wafer (boron-dopped<100> orientation, resistivity of 1~10 ${\Omega}-cm$) and used as a alcohol sensor. Silicon quantum dots displayed an emission band at the wavelength of 675 nm with an excitation wavelength of 480 nm. Photoluminescence of silicon quantum dots was quenched in the presence of alcohol vapors such as methanol, ethanol, and isopropanol. Quenching efficiencies of 21.5, 32.5, and 45.8% were obtained for isopropanol, ethanol, and methanol, respectively. A linear relationship was obtained between quenching efficiencies and vapor pressure of analytes used. Quenching photoluminescence was recovered upon introducing of fresh air after the detection of alcohol. This provides easy fabrication of alcohol sensor based on porous silicon.

Investigation of NOx Formation Charateristics in Multi Air Staged Spray Combustor (공기 다단 분무연소기의 NOx 발생특성에 관한 실험적 연구)

  • Kim, Han-Seok;An, Guk-Yeong;Kim, Ho-Geun;Baek, Seung-Ok
    • 연구논문집
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    • s.31
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    • pp.23-43
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    • 2001
  • An experimental investigation on the reduction of nitrogen oxide emission from swirling, turbulent diffusion flames was conducted using multi air staged combustor, The combustor utilizes swirler to dampen fuel/air mixing, allowing an extended residence time for fuel pyrolysis and fuel-N conversion chemistry in an locally fuel-rich environment prior to burnout. This process also allow to reduce thermal NOx formation to lessen the temperature of reaction zone. The aerodynamic process therefore emulates the conventional staged combustion process, but without the need for the physically separate fuel-rich and -lean stages. Parametric studies on the ratios of each staged air and droplet size were carried out the feasibility of fuel/air mixing for low NOx combustion with diesel and pyridine mixed diesel fuel oil.

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