• Title/Summary/Keyword: excess

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Combustion Emission Characteristics on the Effect of Secondary Air Injection in Model Gas Turbine Combustor (모형 가스터빈 연소기의 2차공기 주입에 따른 연소배출특성)

  • 김규성;임경달;이도형
    • Journal of Ocean Engineering and Technology
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    • v.14 no.3
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    • pp.84-89
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    • 2000
  • The purpose of this study is to investigate the combustion emission characteristics by the effect of secondary air injection and variation of the excess air ratio in combustion field of model gas turbine combustor. For this purpose, mean temperature, CO, $CO_2$, $O_2$ and HC concentrations were measured by changing excess air ratio and secondary air injection. As a result of this study, mean temperature was decreased and CO, HC emission increased by increasing the excess air ratio of secondary air. Therefore, this results showed the secondary air injection effected strongly on the flame structure and combustion emission characteristics.

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Effect of MgO Content on Microstructural Evolution and Microwave Dielectric Properties of $Ba(Mg_{1/3}Ta_{2/3})O_3$ Ceramics (MgO 변화량에 다른 $Ba(Mg_{1/3}Ta_{2/3})O_3$ [BMT]계 세라믹스의 미세조직변화와 마이크로파 유전특성)

  • 이정아;김정주;이희영;김태홍;최태구
    • Journal of the Korean Ceramic Society
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    • v.31 no.11
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    • pp.1299-1306
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    • 1994
  • Effect of MgO content on microstructural evolution and microwave dielectric properties of Ba(Mg1/3Ta2/3)O3 system was investigated. MgO content was varied from 10 mol% deficiency to 10 mol% excess of stoichiometric composition, respectively. It was found that MgO-deficient specimen showed faster grain growth rate than stoichometric and MgO excess BMT system. Besides, sandwich type precipitates of Ba5Ta4O15 which was formed within the BMT grain, might lead to the anisotropic grain growth of BMT grain. On the contrary, in MgO excess specimen, BMT grain growth rate was retarded by precipitations of MgO phase in grain boundary. Besides, the Q values of MgO-deficient showed lower than MgO-excess due to precipitations of Ba5Ta4O15 within BMT grain.

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Dielectric properties of $Bi_{3.25}La_{0.75}Ti_3O_{12}$ thin films with Bi contents (Bi 첨가량에 따른 BLT 박막의 유전특성)

  • 김경태;김창일;강동희;심일운
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07a
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    • pp.371-374
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    • 2002
  • Bismuth lanthanum titanate thin films with excess Bi contents were prepared onto Pt/Ti/$SiO_2$/Si substrate by metalorganic decomposition (MOD) technique. The structure and morphology of the films were analyzed using X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. From the XRD analysis, BLT thin films show polycrystalline structure and the layered-perovskite phase was obtained over 10% excess of Bi contents. As a result of ferroelectric characteristics related to the Bi content of the BLT thin film, the remanent polarization and dielectric constant decreased with increasing over Bi content of 10 % excess. The BLT film with Bi content of 10% excess was measured to have a dielectric constant of n9 and dielectric loss of 1.85[%]. The BLT thin films showed little polarization fatigue test up to 3.5 x $10^{9}$ bipolar switching cycling.

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Effects of Secondary Air Injection in Combustion Field of Model Gas Turbine Combustor (모형 가스터빈 연소기에서 2차공기 주입이 연소장에 미치는 영향)

  • 김규성;임경달;이동형
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2000.04a
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    • pp.171-176
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    • 2000
  • This purpose of this study is to investigate the combustion emission characteristics on the effect of secondary air injection in combustion field of model gas turbine combustor changing excess air ratio. For this purpose, meantemperature, CO, CO2, O2 and HC concentration were measured by changing excess air ratio and secondary air injection. As a result of this study, meantemperature, CO2 emission was decreased and CO emission increased by increasing the excess air ratio of secondary air. therefore, This paper showed the effect of Secondary air injection on flame structure, combustion emission characteristics.

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Design and Performance Evaluation of Sludge Dewatering System based on Electrocoagulation and Electroosmosis (전기응집 및 전기탈수을 이용한 슬러지 탈수 성능평가 분석)

  • Shin, Hee-Soo;Yeo, Chang-Sin;Byun, Sang-Hyun;Lee, Jae-Keun
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.1992-1997
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    • 2003
  • This study is to develop the pretreatment for the excess and digested sludge by electro-coagulation and dewatering. Electrocoagulation is applied to excess and digested sludge before transferring to the piston type press for dewatering. Piston type filter press as a laboratory scale plant was used to estimate the dewaterability. MMD of excess sludge was increased from initial diameter of particles(34.16 ${\mu}m$) to the 87%(64.01 ${\mu}m$) after electrocoagulation. AI electrode is more effective than Fe electrode for the dewaterability of excess sludge. Electrodewatering after electrocoagulation as pretreatment makes the water content of sludge cake $50{\sim}60$ wt%.

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Research In Developing of Diagnosis Questionnaires on Cold, Heat, Deficiency and Excess (한열허실(寒熱虛實) 변증(辨證) 진단(診斷) 설문지의 개발에 대한 연구)

  • Cho, Hye-Sook;Bae, Geung-Mee
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.23 no.2
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    • pp.288-293
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    • 2009
  • This study was investigated developing of Diagnosis Questionnaires which were used by Oriental Medical hospital of Dong-Eui University. We analyzed the results of Questionnaires about 620 outpatients who had participated study of diagnosis Dong-Eui University from April 2006 to March 2007. Pretest score in outcome reliability were similar on Cold, Heat, Deficiency and Excess. In Diagnosis Questionnaires, the number of variables below applied to Cold was 13, Hot was 8, Deficiency was 9, Excess was 7.

Regenerated Power in Fixed voltage DC Electric Power Supply System (정전압 DC 급전시스템에서의 회생전력)

  • 정상기;이병송;정락교;박성혁;김국진
    • Proceedings of the KSR Conference
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    • 2001.10a
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    • pp.343-349
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    • 2001
  • In this study we examined the method to estimate numerically the amount of the regenerated power and the excess regenerated power produced in the DC electric power supply system for the urban light rail transit system. And their economic feasibilities are also studied. For this study DC electric power supply system is simulated and the numerical analysis of the regenerated power and the excess regenerated power are conducted. The study result on the sample system shows that the facility to consume the excess regenerated power or the inverting equipment to reuse the excess regenerated power in the electric substation is feasible economically.

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Study on the Impact of the Private Credit Excess on the Credit Risk under the Massive Capital Inflows

  • Kim, Jong-Hee
    • East Asian Economic Review
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    • v.20 no.3
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    • pp.391-423
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    • 2016
  • By examining the relationship between private credit growth and the possibility of credit risk while focusing on international capital in 21 countries over the period 2000:1Q-2015:2Q, this paper shows that the impact of private credit growth on credit risk is apparent under the high ratio of capital inflows, and its impact on credit risk in the seven Asian countries is even stronger. And the possibility of credit risk caused by private credit is mainly coming from portfolio inflows rather than direct inflows. Finally, portfolio inflows strengthen the positive relationship between credit excess and credit risk in Asian countries, and this trend is seen more in these after the global financial crisis. Taken together, the stronger positive relationship between credit excess and credit risk can be strengthen under the massive portfolio inflows in particular in the seven Asian countries such as Hong Kong, India, Indonesia, Korea, Malaysia, Singapore, and Thailand.

An Excess Carrier Lifetime Extraction Method for Physics-based IGBT Models

  • Fu, Guicui;Xue, Peng
    • Journal of Power Electronics
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    • v.16 no.2
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    • pp.778-785
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    • 2016
  • An excess carrier lifetime extraction method is derived for physics-based insulated gate bipolar transistor (IGBT) models with consideration of the latest development in IGBT modeling. On the basis of the 2D mixed-mode Sentaurus simulation, the clamp turn-off test is simulated to obtain the tail current. The proposed excess carrier lifetime extraction method is then performed using the simulated data. The comparison between the extracted results and actual lifetime directly obtained from the numerical device model precisely demonstrates the accuracy of the proposed method.

Generating efficiency and NOx emissions of a gas engine generator fuelled with biogas (바이오가스를 이용한 가스엔진 발전기의 발전효율 및 질소산화물 배출 특성)

  • Lee, Kyung-Taek;Cha, Hyo-Seok;Chun, Kwang-Min;Song, Soon-Ho
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.306-309
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    • 2009
  • Concern for new and renewable energy is growing globally. Biogas is one of the alternative fuels and consists of methane and carbon dioxide. It is difficult to achieve efficient engine operation due to a lower heating value of biogas compared to that of natural gas. In order to improve generating efficiency, finding an optimum point of ignition timing and excess air ratio is important. From this fact, generating efficiency and pollutant emissions of 2300cc gas engine generator operated by biogas as functions of ignition timings and excess air ratios were investigated in this study. As a test result, the generating efficiency of the gas engine generator using biogas was 27.34 % in the condition of the BTDC of $16^{\circ}$ and the excess air ratio of 1.4.

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