• Title/Summary/Keyword: Radical intensity

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An Experimental Study on Flame Structure and Combustion Characteristics of Turbulent Diffusion Flame(II) (난류확산화염의 화염구조와 연소특성에 관한 실험적 연구(2))

  • Choe, Byeong-Ryun;Jang, In-Gap;Choe, Gyeong-Min
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.3
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    • pp.1050-1060
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    • 1996
  • Recently, attention has been paid to the flame diagnostic by noncontact methods which dose not deform the flame shape. One of them is a method which is using the radical luminous intensity. Generally, this diagnostic method using radical luminous has been investigated its reliability by applying to laminar flame. This study, however, investigated each radical luminous signals through stocastical analysis like auto-correlation, cross-correlation, phase and coherence which were acquired from measuring radical luminous intensity of OH, CH, $O_{2}$, radicals in turbulent diffusion flame. To compare radical luminous intensity in flame with temperature, ion current and concentration , radious distribution of each properties was investigated and considered. In radical luminous intensity, correlation in the reaction zone of flame was higher than in correlation in combusted gas zone. And radious distribution of radical luminous intensity was corresponded with radious distribution of temperature, ion current and concentration. The result of the study confirms that a radical luminous flame diagnosis is possible in the turbulent diffusion flame.

An Experimental Study on Flame Structure and Combustion Characteristics of Turbulent Diffusion Flame(III) (난류확산화염의 화염구조와 연소특성에 관한 실험적 연구)

  • Jang, In-Gap;Choe, Gyeong-Min;Choe, Byeong-Ryun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.7
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    • pp.2326-2336
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    • 1996
  • So most practical combustor is considered to the swirl flame, it is very important to examinate swirl flame structure and combustion characteristics. Recently, attention has been paid to the flame diagnostic by radical luminous intensity. For swirl flame structure and combustion characteristic, reverse flow boundary, temperature, ion current and radical luminous intensity were measured in the double-coaxial swirl combustor which was used principle of multi-annular combustor. This study had three experimental condition, S-type, C-type, SC-type. S-type and C-type flames were formed recirculation zone, but SC-type flame wasn't formed. C-type flame had two recirculation zone. The position with maximum value of ion current and CH-radical, temperature and OH-radical had similarity distribution almost. Therefore, it is possible that the macro structure of flame was measured by radical luminous intensity in the high intensity of turbulent combustion field which was formed by swirl.

Combustion Characteristics of Model Gas Turbine Combustor -Radical Luminous Intensity and Local Equivalence Ratio Measurement- (모형 가스터빈 연소기의 연소특성 -라디칼 자발광강도와 국소당량비계측에 대하여-)

  • 최병륜;김태한
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.4
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    • pp.1064-1071
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    • 1994
  • There are three active radicals which become to the scale of flame diagnostics at the flame front. They are OH, CH and $C_2$ radical. For this, optical measurement system which could monitor simultaneously the luminous waves of three radicals, was constructed. These were analyzed statistically into the cross correlation, coherence and phase. Through such an statistical treatment, combustion characteristics was investigated at the primary zone of gas turbine combustor. The local equivalence ratio was predicted with the ratio of luminuous intensity between CH and $C_2$ radical. This result was matched up to the equivalence ratio calculated from gas composition within 5% error. In general, equivalence ratio was said to be 1.0 at flame front, but it could be increased up to about 1.2 depending on the degree of swirl intensity in case of changing properly the air amount of primary zone.

Extracorporeal High Intensity Focused Ultrasound Therapy (체외강력집속초음파치료)

  • Han, Sang-Suk
    • The Journal of the Korean bone and joint tumor society
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    • v.11 no.1
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    • pp.17-24
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    • 2005
  • Local treatment for tumors has developed from extended radical surgery to function preserving surgery on the basis of modern biology. With the development of minimally invasive technique, it changed to be minimal-invasive surgery. And nowadays technical revolution made non-invasive surgery possible with appearance of several kinds of non-surgical knives such as gamma knife, cyber knife, and HIFU (high intensity focused ultrasound) knife. In this article, history, HIFU machine and treatment procedure, histological change and its mechanism, clinical applications, advantage, disadvantage, and future prospect of extracorporeal high intensity focused ultrasound therapy using HIFU knife will be reviewed.

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Frequency, Intensity and Daily Life Distress of Urinary Dysfunction in Women with Cervical Cancer after Radical Hysterectomy (근치적자궁절제술을 받은 자궁경부암 여성의 배뇨장애 빈도, 강도 및 일상생활 불편감)

  • Chun, Nami;Noh, Gie Ok;Song, Hyun Ju;Kim, Sang Hee
    • Journal of Korean Academy of Nursing
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    • v.46 no.3
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    • pp.400-408
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    • 2016
  • Purpose: This study was done to identify frequency, intensity of urinary dysfunction and daily life distress in women after a radical hysterectomy for cervical cancer. Methods: One hundred and fifty seven women who had undergone a radical hysterectomy and one hundred and sixty five women as healthy controls completed questionnaires on intensity of urinary dysfunction and daily life distress caused by urinary dysfunction. Results: Women with cervical cancer showed higher frequency of urinary dysfunction than healthy controls. Major urinary dysfunction for women with cervical cancer in order of frequency were night-time incontinence (odds ratio=10.39, p<.001), difficulty in starting urination, weak urine stream and sense of incomplete emptying of bladder. The highest score on intensity was difficulty in starting urination, followed by urgency, weak urine stream, daytime frequency and sense of incomplete emptying. Night-time incontinence was the urinary symptom causing the most daily life distress for cervical cancer women followed by difficulty in starting urination, urgency, sense of incomplete emptying, and night-time frequency. Conclusion: Results suggest that nurses should address the potential postoperative urinary complications and develop long term interventions to decrease urinary dysfunction and daily life distress for women who have had a radical hysterectomy for cervical cancer.

A Study of Electron Paramagnetic Resonance of Sugar Irradiated X-ray (X-선에 조사된 설탕의 전자 상자성 공명 연구)

  • Ok, Chi-Il;Son, Phil-Kook;Heo, Kyoung-Chan;Shon, Jong-Gi;Lee, In;Kim, Jang-Whan
    • Journal of radiological science and technology
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    • v.23 no.2
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    • pp.39-42
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    • 2000
  • When ordinary sugar is exposed to ionizing radiation, a number of free radical are created in sugar, and Electron Paramagnetic Resonance (EPR) signal appears from the sugar because of the paramagnetic property of free radical. In this paper, EPR signal intensity has been measured in x-ray irradiated sugar for various absorbed doses, irradiated dose up to 50 Gy. The EPR intensity signals are increased as the x-ray irradiation increases. Also, the fading value decreased to about 3% in 30day after the irradiation. Therefore, the sugar is a useful material for emergency dosimeter as the free radical dosimetry with the EPR equipment.

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Observation of Rotational Cooling of CN($B^2{\Sigma}^+$) Radical Generated in a Supersonic Expansion

  • Lee, Sang-Kuk;Choi, Iek-Soon;Kim, Un-Sik
    • Bulletin of the Korean Chemical Society
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    • v.15 no.5
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    • pp.353-356
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    • 1994
  • The $CN(B^2{\Sigma}^+)$ radical was produced in a jet using an electric dc discharge of the precursor $CH_3CN$ with inert carrier gases. The rotationally resolved Fourier transform emission spectra of the 0-0 band of the $(B^2{\Sigma}^+{\to}X^2{\Sigma}^+)$ transition of CN have exhibited different distribution of the intensity for the carrier gases He and Ar, respectively. From the analysis of intensity distribution in the spectra, the mechanism for rotational cooling process of CN radical in a supersonic expansion has been suggested.

Study on the Measurement of Emission Spectrum and Reaction Mechanism of OH Radical in the Nitrogen Corona Discharge System for Removal of $NO_x$ in Flue Gas (배연가스의 $NO_x$제거용 코로나 방전장치에서 OH 발광 스펙트럼 측정 및 관련 반응 연구)

  • Park, Chul-Woung;Hahn, Jae-Won;Shin, Dong-Nam
    • Journal of the Korean Society of Combustion
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    • v.4 no.1
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    • pp.27-38
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    • 1999
  • We constructed a wire-cylinder type pulsed corona discharge system for $NO_x$ removal, which was operated in room temperature. A emission spectrometer was built with a boxcar averager and monochrometer equipped with photo-multiplier tube detector. The sensitivity of the emission spectrometer was greatly improved by synchronizing the emission spectrometer with pulsed corona discharge system using a triggered spark-gap switch. $N_2$ spectrum($c^3{\Pi}_u{\rightarrow}X^1{\Sigma}_g{^+}$) was measured in the range of 300 - 450 nm and oxidizing OH radical emission($A^2{\Sigma}^+{\rightarrow}X^2{\Pi}$) was measured in case $N_2$ was supplied with water bubbling. As wet gas composition of inlet $N_2$ supplied in the discharge system increased, the intensity of OH emission was increased and saturated at wet gas composition 50%. We also investigated additive effect of $C_2H_4,\;H_2O,\;H_2O_2$ on the intensity of OR emission and $NO/NO_2/NO_x$ reduction and analysed the related reaction mechanism in corona discharge process. $H_2O_2$ additive increased the intensity of OH emission and $NO/NO_x$ reduction.

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Experimental Investigation on premixed combustion Characteristics with suction & blow fans (송풍기와 폐풍기를 이용한 연소기내의 부분 예혼합화염 연소 특성에 관한 실험적 연구)

  • Kang, B.K.;Oh, S.H.
    • Proceedings of the KSME Conference
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    • 2001.11b
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    • pp.143-148
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    • 2001
  • We measured emission indices for $NO_x$, CO, temperature and radical characteristics for partially premixied flames formed by suction & blow fans air condition. At sufficiently high levels of partial premixing a double flame structure consisting of a rich premixed inner flame and outer diffusion flame was established similar to that previously observed in premixed flames. $NO_x$, Temperature, CO values were experimented with approximately constant air flow rate and decreasing equivalence ratios. The reduction in $NO_x$ and temperature at suction condition as compared with that for blow condition was approximately 20%, but on the contrary, CO emission was increased. In addition, We measured temperature distributions and found that temperature increased continuously with increasing partial premixing. We also estimated CH, $C_2$ radical intensity. CH and $C_2$ radicals provide evidence that, for the present measurement, CH and $C_2$ radicals intensity was associsated with their premixed component. And we observed stronger $C_2$, CH radicals intensity at suction conditions than blow conditions.

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Experimental Investigation on Premixed Combustion Characteristics with Suction & Blow Fans (Suction과 blow fan을 이용한 연소기내의 부분 예혼합화염 연소 특성에 관한 실험적 연구)

  • Kang, Ki-Bal;Kim, Dong-Il;Oh, Sang-Heun
    • Journal of the Korean Society of Combustion
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    • v.7 no.2
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    • pp.15-23
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    • 2002
  • We measured emission indices for $NO_x$, CO, temperature and radical characteristics for partially premixied flames formed by suction & blow fans air condition. At sufficiently high levels of partial premixing a double flame structure consisting of a rich premixed inner flame and outer diffusion flame was established similar to that previously observed in premixed flames. $NO_x$, Temperature. CO concentration were experimented with approximately constant air flow rate and decreasing equivalence ratios. The reduction in $NO_x$, and temperature at suction condition as compared with that for blow condition was approximately 20%, but on the contrary, CO emission was increased. In addition, We measured temperature distributions and found that temperature increased continuously with increasing partial premixing. We also estimated CH, $C_2$ radical intensity. CH and $C_2$ radicals provide evidence that, for the present measurement, CH and $C_2$ radicals intensity was associsated with their premixed component. And we observed stronger $C_2$, CH radicals intensity at suction conditions than blow conditions.

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