• Title, Summary, Keyword: anti-stokes emission

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Experimental Study on Flame Structure and Temperature Characteristics in a Lean Premixed Model Gas Turbine Combustor

  • Lee Jong Ho;Jeon Chung Hwan;Chang Young June;Park Chul Woong;Hahn Jae Won
    • Journal of Mechanical Science and Technology
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    • v.19 no.6
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    • pp.1366-1377
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    • 2005
  • Experimental study was carried out in an atmospheric pressure, laboratory-scale dump combustor showing features of combustion instabilities. Flame structure and heat release rates were obtained from OH emission spectroscopy. Qualitative comparisons were made between line-integrated OH chemiluminescence image and Abel-transformed one. Local Rayleigh index distributions were also examined. Mean temperature, normalized standard deviation and temperature fluctuations were measured by coherent anti-Stokes Raman spectroscopy (CARS). To see the periodic behavior of oscillating flames, phase-resolved measurements were performed with respect to the pressure wave in the combustor. Results on system damping and driving characteristics were provided as a function of equivalence ratio. It also could be observed that phase resolved temperatures have been changed in a well-defined manner, while its difference between maximum and minimum reached up to 280K. These results would be expected to play an important role in better understanding of driving mechanisms and thermo-acoustic interactions.

A case report of a clinically diagnosed advanced lung cancer patient after treatment with Gunchilgyebok-Jung (건칠계복정으로 치료한 임상적 진행성 폐암 환자 1례)

  • Park, So jung;Kang, Hwi joong;Park, Ji hye;Cho, Chong kwan;Yoo, Hwa seung
    • Journal of Korean Traditional Oncology
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    • v.20 no.1
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    • pp.23-29
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    • 2015
  • Objective : This case report presents the effects of Gunchilgyebok-Jung to a patient who was clinically diagnosed with advanced lung cancer. Methods : The study involved a 74-year-old male patient clinically diagnosed with advanced (stage III) lung cancer by chest computed tomography (CT) and positron emission tomography. The patient had two masses (11.32 mm and $23.03mm{\times}35.34mm$) in the right upper lobe of the lung and in the mediastinum respectively. Gunchilgyebok-Jung commonly used for its anti-tumor and anti-inflammatory effect is composed of Rhus verniciflua stokes and Guizhifuling wan extracts. We prescribed Gunchilgyebok-Jung at a dosage of 1 g three times a day for 50 days. Results : After the administration of Gunchilgyebok-Jung, a decrease in tumor size to 10.69 mm and $22.71mm{\times}34.21mm$ on chest CT was observed. A numerical rating scale (NRS) showed an improvement in symptoms from points 7-8 to 3-4. Conclusion : This study suggests that Gunchilgyebok-Jung may have considerable anti-tumor and immunopotentiating activity in lung cancer without any adverse effects.

Phase-resolved CARS Temperature Measurements in a Lean Premixed Gas Turbine Combustor (2);Effect of equivalence ratio on phase-resolved gas temperature (CARS를 이용한 희박 예혼합 가스터빈 연소기내 온도 측정 (2);당량비가 위상별 온도에 미치는 영향)

  • Lee, Jong-Ho;Moon, Gun-Feel;Park, Chul-Woong;Hahn, Jae-Won;Jeon, Chung-Hwan;Chang, Young-June
    • 한국연소학회:학술대회논문집
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    • pp.103-108
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    • 2003
  • The effect of equivalence ratio and fuel/air mixing quality on the phase-resolved gas temperatures at different phases of the oscillating pressure cycle was experimentally investigated. An atmospheric pressure, optically accessible and laboratory-scale dump combustor operating on methane with heat release rate of 1.59kW was used. Temperature measurements were made using coherent anti-Stokes Raman spectroscopy (CARS) at several spatial locations for typical unstable combustion conditions. Analysis was conducted using parameters such as phase-resolved averaged temperature, normalized standard deviation and temperature probability distribution functions (PDFs). Also the probability on the occurrence of high temperature (over 1900K) was investigated to get the information on the perturbation of equivalence ratio and NOx emission characteristics. It was shown that most of temperature histograms exhibit Gaussian profile which has short breadth of temperature fluctuation at equivalence ratio of 0.6, while beta profile was predominant for the cases of other equivalence ratios (${\Phi}$=0.55, 0.50). The characteristics on the occurrence of high temperature also displayed periodic wave form which is very similar to the pressure signal. And the amplitude of this profile goes larger as the fuel/air mixing quality become poorer. These also provided additional information on the perturbation of equivalence ratio at flame as well as NOx emission characteristics.

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Upconversion Mechanisms in $Tm^{3+}$-doped Glasses under 800 nm Excitation (800nm 파장 여기관에 의한 $Tm^{3+}$첨가 유리내 상향 전이 현상 기구)

  • Jeong, Hoon;Chung, Woon-Jin;Heo, Jong
    • Journal of the Korean Ceramic Society
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    • v.37 no.2
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    • pp.111-116
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    • 2000
  • 700nm red emission(3F3longrightarrow3H6) in Tm3+ ion with 800 nm(3H6longrightarrow3H4) excitation via upconversion process has been reported only in host materials which have low phonon energies such as halide crystals. However, we observed 700nm and 480nm(1G4longrightarrow3H6) upconverted emission with 800nm excitation in several oxide glasses which has never reported. With spectroscopic analyses and lifetime measurements of each nergy level of Tm3+ ion doped in various oxide glasses, following mechanisms are suggested. For red upconversion, upconversion mechanism changed with Tm3+ concentration. While direct excitation up to 3F3 level via anti-Stokes excitation was dominated at low concentration, two-step excitation via 3H6longrightarrow3H4 and 3F4longrightarrow3F3 transitions was dominated at high concentration. For blue upconversion, two step excitation mechanism up to 1G4 level was suggested as follows : electrons are exciated up to 3H5 with direct excitation with pumping light up to 3H4 followed by multiphonon relaxation, and then additional reabsorption of pumping light excites electrons up to 1G4.

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Phase-Resolved CARS Temperature Measurement in a Lean Premixed Gas Turbine Combustor (II) -Effect of Equivalence Ratio on Phase-Resolved Gas Temperature- (CARS를 이용한 희박 예혼합 가스터빈 연소기내 온도 측정 (II)-당량비가 위상별 온도에 미치는 영향-)

  • Lee Jong Ho;Jeon Chung Hwan;Park Chul Woong;Hahn Jae Won;Chang Young June
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.10
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    • pp.1193-1201
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    • 2004
  • The effect of equivalence ratio and fuel/air mixing quality on the phase-resolved gas temperatures at different phases of the oscillating pressure cycle was experimentally investigated. An atmospheric pressure, optically accessible and laboratory-scale dump combustor operating on methane with heat release rate of 1.59kW was used. Temperature measurements were made using coherent anti-Stokes Raman spectroscopy (CARS) at several spatial locations fur typical unstable combustion conditions. Analysis was conducted using parameters such as phase-resolved averaged temperature, normalized standard deviation and temperature probability distribution functions (PDFs). Also the probability on the occurrence of high temperature (over 1900K) was investigated to get the information on the perturbation of equivalence ratio and NOx emission characteristics. It was shown that most of temperature histograms exhibit Gaussian profile which has short breadth of temperature fluctuation at equivalence ratio of 0.6, while beta profile was predominant for the cases of other equivalence ratios (${\Phi}$=0.55, 0.50). It was also shown that phase-resolved averaged temperature oscillated in phase with pressure cycle, while normalized standard deviations which represent temporal turbulent intensity of temperature showed nearly constant value around 0.1. The characteristics on the occurrence of high temperature also displayed periodic wave form which was very similar to the pressure signal. And the amplitude of this profile went larger as the fuel/air mixing quality became poorer. These also provided additional information on the perturbation of equivalence ratio at flame as well as NOx emission characteristics.

Optical Diagnostics of Nanopowder Processed in Liquid Plasmas

  • Bratescu, M.A.;Saito, N.;Takai, O.
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.17-18
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    • 2011
  • Plasma in liquid phase has attracted great attention in the last few years by the wide domain of applications in material processing, decomposition of organic and inorganic chemical compounds and sterilization of water. The plasma in liquid is characterized by three main regions which interact each - other during the plasma operation: the liquid phase, which supply the plasma gas phase with various chemical compounds and ions, the plasma in the gas phase at atmospheric pressure and the interface between these two regions. The most complex region, but extremely interesting from the fundamental, chemical and physical processes which occur here, is the boundary between the liquid phase and the plasma gas phase. In our laboratory, plasma in liquid which behaves as a glow discharge type, is generated by using a bipolar pulsed power supply, with variable pulse width, in the range of 0.5~10 ${\mu}s$ and 10 to 30 kHz repetition rate. Plasma in water and other different solutions was characterized by electrical and optical measurements. Strong emissions of OH and H radicals dominate the optical spectra. Generally water with 500 ${\mu}S/cm$ conductivity has a breakdown voltage around 2 kV, depending on the pulse width and the repetition rate of the power supply. The characteristics of the plasma initiated in ultrapure water between pairs of different materials used for electrodes (W and Ta) were investigated by the time-resolved optical emission and the broad-band absorption spectroscopy. The deexcitation processes of the reactive species formed in the water plasma depend on the electrode material, but have been independent on the polarity of the applied voltage pulses. Recently, Coherent anti-Stokes Raman Spectroscopy method was employed to investigate the chemistry in the liquid phase and at the interface between the gas and the liquid phases of the solution plasma system. The use of the solution plasma allows rapid fabrication of the metal nanoparticles without being necessary the addition of different reducing agents, because plasma in the liquid phase provides a reaction field with a highly excited energy radicals. We successfully synthesized gold nanoparticles using a glow discharge in aqueous solution. Nanoparticles with an average size of less than 10 nm were obtained using chlorauric acid solutions as the metal source. Carbon/Pt hybrid nanostructures have been obtained by treating carbon balls, synthesized in a CVD chamber, with hexachloro- platinum acid in a solution plasma system. The solution plasma was successfully used to remove the template remained after the mesoporous silica synthesis. Surface functionalization of the carbon structures and the silica surface with different chemical groups and nanoparticles, was also performed by processing these materials in the liquid plasma.

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Efficient Triplet-triplet Annihilation-based Upconversion in Vegetable Oils (식물성 오일에서 구현되는 삼중항-삼중항 소멸법에 의한 Upconversion 분석)

  • Shin, Sung Ju;Choe, Hyun Seok;Park, Eun-Kyoung;Kyu, Hyun;Han, Sangil;Kim, Jae Hyuk
    • Applied Chemistry for Engineering
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    • v.27 no.6
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    • pp.639-645
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    • 2016
  • We herein report efficient triplet-triplet annihilation upconversion (TTA-UC) achieved in various non-toxic and non-volatile vegetable oils as a UC media using platinum-octaethylporphyrin (PtOEP) and 9,10-diphenylanthracene (DPA) as a sensitizer and acceptor, respectively. Green-to-blue UC was readily achieved from PtOEP/DPA solution in vegetable oils with the quantum yield of 8% without any deoxygenation process. The UC efficiency was found to be significantly dependent on the contents of unsaturated hydrocarbon in vegetable oils and viscosity of the solution, as well. Though the Stern-volmer constant and quantum yield in vegetable oils were measured to be lower than those measured in the deaerated organic solvent, the quenching efficiency was still high enough to be 93%. In the sunflower oil, the UC threshold intensity ($I_{th}$) was approx. $100mW/cm^2$, which is far larger than the sunlight intensity, but we believe that the UC achieved in non-toxic and air-saturated media was still highly applicable to nontraditional visualization techniques such as bioimaging.