• 제목/요약/키워드: formation temperature

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퇴적층에서의 가스 하이드레이트 생성 특성 (Formation characteristics of gas hydrate in sediments)

  • 이재형;이원석;김세준;김현태;허대기
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2005년도 춘계학술대회
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    • pp.630-633
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    • 2005
  • Some gases can be formed into hydrate by physical combination with water under appropriate temperature and pressure condition. Besides them, it was found that the pore size of the sediments can affect the formation and dissociation of hydrate. In this study, formation temperatures of carbon dioxide and methane hydrate have been measured using isobaric method to investigate the effects of flow rates of gases on formation condition of hydrate in porous rock samples. The flow rates of gases were controlled using a mass flow controller. To minimize Memory effect, system temperature increased for the dissociation of gas hydrates and re-established the initial saturation. The results show that the formation temperature of hydrate decreases with increasing the injection flow rate of gas. This indicates that the velocity of gas in porous media may act as kinds of inhibitor for the formation of hydrate.

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Genetic studies of Baculovirus used as a microbial pesticide

  • Lee, Hyung-Hoan
    • 한국미생물생명공학회:학술대회논문집
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    • 한국미생물생명공학회 1979년도 추계학술대회 심포지움
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    • pp.248.1-248
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    • 1979
  • Sixteen temperature-sensitive mutants of Autographa californica nuclear polyhedrosis virus were isolated. Several interesting phenotypes were observed. A large proportion of the mutants were un-able to form polyhedral occlusion bodies at the nonpermissive temperature (32.5C). At 32.5C, one mutant formed plaques in which the cells lacked polyhedra. Another mutant type was defective in the production of progeny extracellular nonoccluded virus and produced a plaque consisting of only a single cell containing polyhedra at 32.5C. One mutant was defective in plaque formation, progeny nonocluded virus formation, and polyhedra formation at 32.5C. Several mutants produced nonocluded virus but failed to produce plaques or polyhedra at 32.5C. Other phenotypes were also distinguished. Complementation analyses, performed by either measuring the increase in extracellular non-ocludedvirus formation or by oberving polyhedra formation in mixed infections at 32.5C, indicated the presence of 15 complementation groups. A high frequency of recombination was observed. Four of the mutants were found to be host dependent in their temperature sensitivity for polyhedra formation.

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온도와 광도가 톨루엔-NOx-공기 혼합물의 광산화 반응에 미치는 영향의 비교 (Comparison of Temperature and Light Intensity Effects on the Photooxidation of Toluene-NOx-Air Mixture)

  • 주옥정;배귀남;최지은;이승복;김영성;문길주;윤순창
    • 한국대기환경학회지
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    • 제23권3호
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    • pp.353-363
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    • 2007
  • To differentiate temperature effect from the light intensity effect on the formation of secondary products during the photooxidation of toluene-$NO_x$-air mixtures, steady-state air temperature was changed from $20^{\circ}C\;to\;33^{\circ}C$ at the same light intensity of $0.39min^{-1}$ in an indoor smog chamber. Smog chamber consisted of 64 blacklights and a $5.8m^3$ reaction bag made of Teflon film. Air temperature was controlled by an air-conditioning system. The starting time for rapid conversion of NO to $NO_2$ was slightly delayed with decreasing air temperature. In contrast to light intensity effect, the ozone formation time and the ozone production rate were insensitive to air temperature. Although the formation time for secondary organic aerosols was not changed, the particle number concentration increased with temperature. However, the newly formed secondary organic aerosol mass at lower temperature was higher than that at higher temperature. Since light intensity significantly affected the starting time and quantity of ozone and aerosol formation, it is considered that the temperature could contribute partly the quantity of aerosol formation during the photooxidation of toluene-$NO_x$-air mixtures.

TCE (trichloroethylene)으로부터 클로로벤젠과 클로로페놀의 생성특성 (Formation Characteristics of Chlorobenzenes and Chlorophenols from TCE)

  • 김은미;심영숙;이우근
    • 한국대기환경학회지
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    • 제18권2호
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    • pp.149-159
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    • 2002
  • The objective of this study was to evaluate the formation characteristics of CBs and CPs from TCE, aliphatic compound. The experiment was carried out in a fixed reactor during 30 min under the oxidation condition at the range of temperature, 300~$700^{\circ}C$. MSWI fly ash was used as catalyst in this study. Total amount of CBs formed greater magnitude than that of CPs overall range of reaction temperature. It is proposed that the formation of CPs was caused from hydroxylation of CBs. According to increasing temperature to $600^{\circ}C$, the yield of CBs and CPs increased but significantly decreased at $700^{\circ}C$. It is suggested that decomposition rate was faster than formation rate at the high temperature. In the homologue distribution of CBs, DCBs were major products at 30$0^{\circ}C$ and the amount of higher chlorinated compound increased to $600^{\circ}C$. Because they were formed by chlorination of lower chlorinated compounds. In case of CPs, the amount of DCPs was 90% of total amounts in both thermal formation and catalytic reaction. On the other hand it was clearly observed that the chlorination rate in catalytic reaction was higher than in thermal formation with TCE only.

크랙에 의한 고온 초전도체 테이프의 임계전류 특성변화 (The variation of critical current by the formation of crack in a high-temperature superconducting tape)

  • 박을주;설승윤
    • 한국초전도ㆍ저온공학회논문지
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    • 제4권1호
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    • pp.73-77
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    • 2002
  • The variation of critical current by the formation of crack in a high temperature super-conducting tape was studied by experimental and numerical analyses. The current-voltage relation of HTS tape is measured by the four-point measurement method. Numerical analyses are used to solve two dimensional heat conduction equation, considering the temperature distribution. By comparing current-voltage relation of experimental and numerical results, the validity of numerical method is verified.

동축류 확산화염의 매연생성에 미치는 연료에 첨가된 산화제의 영향 (Effects of Oxidant Addition to Fuel on Soot Formation of Laminar Diffusion Flames)

  • 이원남
    • 한국연소학회지
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    • 제3권1호
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    • pp.11-19
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    • 1998
  • The influence of oxidant addition on soot formation is investigated experimentally with ethylene, propane and mixture fuel co-flow diffusion flames. Oxidant addition into fuel shows the increase of integrated soot volume fractions for ethylene, ethylene/ethane and ethylene/methane mixture flames. However, the increase of integrated soot volume fraction with oxidant addition was not significant for propane and ethylene/propane mixture flames. This discrepancy is explained with $C_2\;and\;C_3$ chemistry at the early stage of soot formation process. The oxidant addition increases the concentration of $C_3H_3$ in the soot formation region, and therefore, enhances soot formation process. A new soot formation rate model that includes both dilution effect and chemical effect of oxygen is suggested to interpret the increase of integrated soot volume fractions with oxidant addition into ethylene. Also, the role of adiabatic flame temperature for the chemical effect of oxygen addition into fuel was reviewed. The influence of oxidant or diluent addition into fuel on soot formation process are the fuel dilution effect, the adiabatic flame temperature altering effect and/or the chemical effect of oxygen. Their relative importance could change with fuel structure and adiabatic flame temperature.

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Experimental study of the frost formation on the cryogenic flat plate with temperature distribution

  • Fujimatsu, Kiyoto;Tanatsugu, Nobuhiro;Sato, Tetsuya
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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    • pp.657-664
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    • 2004
  • In this study, a fundamental experiment was carried out to investigate the frost formation on a cryogenic flat plate with/without temperature distribution from 230K to 160K under the convective flow. The effects of mixing ethanol as a condensable substance were also researched. From the test results, when surface temperature at the upstream is 230K, mass flux is high. On the other hand, when surface temperature at the downstream is 160K, mass flux is low. The degree of improvement to restrain frost formation by ethanol mixing is relatively larger at the upstream than at the downstream.

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Slag-Quartz-$Na_2$$CO_3$계의 Foam형성에 관한 연구 (A Study on Foam Formation of Slag-Quartz-$Na_2$$CO_3$ System)

  • 박현수;김종희;천성순
    • 한국세라믹학회지
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    • 제13권3호
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    • pp.21-27
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    • 1976
  • Foam formation of Slag-Quartz-$\textrm{Na}_2\textrm{CO}_3$ system was investigated. The foaming agent used was sulphide and sulphate compounds which are present in the slag. The microstructures and x-ray analysis of foam slag, the effect of composition and particle size of slag on the formation temperature, and foam size and distribution of slag foam were studied. The Increment of $\textrm{Na}_2\textrm{O}$ in the slag batch composition decrease the initial foam formation temperature and enhance the foam growth. The formation of temperature and soaking time had pronounced effect on the foam growth and increasing the glass phase in the slag foam.

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Irradiation-induced BCC-phase formation and magnetism in a 316 austenitic stainless steel

  • Xu, Chaoliang;Liu, Xiangbing;Xue, Fei;Li, Yuanfei;Qian, Wangjie;Jia, Wenqing
    • Nuclear Engineering and Technology
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    • 제52권3호
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    • pp.610-613
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    • 2020
  • Specimens of austenitic stainless steel were irradiated with 6 MeV Xe ions to two doses of 7 and 15 dpa at room temperature and 300 ℃ respectively. Then partial irradiated specimens were subsequently thermally annealed at 550 ℃. Irradiation-induced BCC-phase formation and magnetism were analyzed by grazing incidence X-ray diffraction (GIXRD) and vibrating sample magnetometer (VSM). It has been shown that irradiation damage level, irradiation temperature and annealing temperature have significant effect on BCC-phase formation. This BCC-phase changes the magnetic behavior of austenitic stainless steel. The stress relief and compositional changes in matrix are the driving forces for BCC-phase formation in austenitic stainless steel during ion irradiation.

Temporal Variation of Air Temperature in Ice-Valley at Milyang in Association with Ice Formation

  • Lee, Soon-Hwan;Hwang, Soo-Jin
    • 한국지구과학회지
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    • 제28권5호
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    • pp.598-602
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    • 2007
  • A long-term in situ observation was carried out in the Ice-valley at Milyang in order to explain the factors and processes associated with the summertime ice formation. The variation of temperature inside Ice-valley in relation with ice formation in summer time was found to depend on precipitation rate in spring and cold air sinking in autumn and winter. The rate of temperature rising tends to correspond to sensible heat release depending on the precipitation amount at the freezing location. The reason of the cold air accumulation in a talus in the Ice-valley is the cold air sinking over the surface of talus due to the occurrence of outside clod air mass and the accumulated cold air from autumn to spring flow outside at the bottom of talus. The out-flowing cold air can result in the ice formation in the hot summer.