• Title, Summary, Keyword: stoichiometric

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Experimental Study on Spray Characteristics of Piezo Injector Group-hole Nozzle for Common Rail Diesel Engine (커먼레일 디젤기관용 피에조 인젝터 그룹홀 노즐의 분무 특성에 관한 실험적 연구)

  • Sung, K.A.
    • Journal of the Korea Society For Power System Engineering
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    • v.12 no.5
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    • pp.14-19
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    • 2008
  • In order to meet stringent future emission regulations, especially to reduce Particulate Matter (PM) and NOX, stoichiometric diesel combustion technology with a piezo group-hole nozzle injector is being researched for reduction harmful emissions. A new nozzle layout, namely a group-hole nozzle, which has one group of small orifices with a wide spray included angle was investigated to improve the efficiency of stoichiometric diesel combustion. From this point of view, the group-hole nozzle suggested by Dense Co. is an attractive candidate method applicable to stoichiometric diesel combustion. The group-hole nozzle concept is to reduce the injector nozzle hole diameters without sacrificing spray penetration by closely locating two holes. Experimental studies have proven that the spray from group-hole nozzles have similar spray penetration to that of a single hole with equivalent overall nozzle hole area, but the spray drop sizes (SMD) are reduced, aiding vaporization and mixing.

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Operational Optimization of Anodic/cathodic Utilization for a Residential Power Generation System to Improve System Power Efficiency (가정용 연료전지 시스템의 전기 효율 향상을 위한 연료/공기 이용률 운전 최적화)

  • Seok, Donghun;Kim, Minjin;Sohn, Young-Jun;Lee, Jinho
    • Transactions of the Korean hydrogen and new energy society
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    • v.24 no.5
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    • pp.373-385
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    • 2013
  • To obtain higher power efficiency of Residential Power Generation system(RPG), it is needed to operate system on optimized stoichiometric ratios of fuel and air. Stoichiometric ratios of fuel/air are closely related to efficiency of stack, reformer and power consumption of Balance Of Plant(BOP). In this paper, optimizing stoichiometric ratios of fuel/air are conducted through systematic experiments and modeling. Based on fundamental principles and experimental data, constraints are chosen. By implementing these optimum values of stoichiometric ratios, power efficiency of the system could be maximized.

Growth and Variance of Properties Er2O3 Doped Near Stoichiometric LiNbO3Single Crystals by the Czochralski Method (Czochralski법으로 Er2O3이 첨가된 Near Stoichiometric 조성 LiNbO3 단결정의 성장 및 특성변화)

  • ;;;Masayuki Habu;Takeshi Ito;Masakimi Natori
    • Journal of the Korean Ceramic Society
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    • v.40 no.8
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    • pp.746-750
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    • 2003
  • Using the Czochralski method, Er$_2$O$_3$ doped near stoichiometric LiNbO$_3$ single crystals were grown 15~20 mm in diameter and 30-35 mm in length for Z-axis. Lattice constants were inspected by the X-Ray Diffractometer (XRD) and through Fourier Transform-Infrared Spectrophotometer (FT-IR), it observed absorption band. Also, the distributions of Er concentration were confirmed by the Electron Probe Micro Analysis (EPMA).

Estimation of Optimal Operation Conditions in Step Feed Processes Based on Stoichiometric Nitrogen Removal Reactions

  • Lee, Byung-Dae
    • Journal of the Korean Applied Science and Technology
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    • v.28 no.1
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    • pp.6-9
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    • 2011
  • Step feed process was analyzed stoichiometrically for the optimal operation conditions in this study. In case of optimal operation conditions, minimum R (sludge recycling) value, r (internal recycling ratio) value, and n (influent allocation ratio) value for the step feed process to acquire the maximum TN removal efficiency were identified by theoretical analysis. Maximum TN removal efficiency, based on stoichiometric reaction, can be obtained by controlling n value for the step feed process.

Catalytic and Stoichiometric Synthesis of Ferrocene-Containing Polyazamacrocycles and Chelating Bidentate Nitrogen Ligands

  • 김은진;권순철;심상철;김태정;정종화
    • Bulletin of the Korean Chemical Society
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    • v.18 no.6
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    • pp.579-584
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    • 1997
  • A series of ferrocene-containing chelating bidentate nitrogen ligands (1 & 2) and polyazamacrocycles (3 & 4) were prepared in high yields from the reaction of ferrocenecarboxaldehydes with corresponding diamines under various catalytic and stoichiometric reaction conditions. The stoichiometric condensation to form Schiff bases required the presence of MgSO₄in the reaction mixture as a water-absorbent. Employment of cyclic diamines such as 1,2-diaminocyclohexane and p-phenylenediamine in the reaction with 1,1'-ferrocenedicarboxaldehyde resulted in the formation of polymers in stead of the expected macrocycles. All these compounds were characterized by microanalytical and spectroscopic techniques. In one case, the structure of 3a was confirmed by X-ray crystallography.

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Optimization of Anodic/cathodic Utilization for a Residential Power Generation System (가정용 연료전지 시스템의 연료/공기 이용률 최적화)

  • Seok, Donghun;Kim, Minjin;Lee, Jinho
    • 한국신재생에너지학회:학술대회논문집
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    • pp.93.1-93.1
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    • 2011
  • To obtain higher power efficiency of Residential Power Generation System(RPG), it is needed to operate system on optimized stoichiometric ratio of fuel and air. In this paper, optimizing stoichiometric ratio of fuel/air is conducted through systematic experiments and modeling. Based on fundamental principles and experimental data, constraints are chosen. Using these stoichiometric ratios as decision variables, maximum power efficiency of system could be found. As a result of research, power efficiency of RPG system is improved.

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A Study on the Deposition Condition for Stoichimetric $\textrm{Ta}_2\textrm{O}_5$ Thin Films by DC Magnetron Reactive Sputtering Technique (DC Magnetron 반응성 스퍼터링 방법을 이용한 stoichiometric $\textrm{Ta}_2\textrm{O}_5$막의 증착조건에 관한 연구)

  • Jo, Seong-Dong;Baek, Gyeong-Uk
    • Korean Journal of Materials Research
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    • v.9 no.6
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    • pp.551-555
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    • 1999
  • The deposition condition to obtain stoichiometric $Ta_2$O\ulcorner films, which is still controversial, using magnetron reactive sputtering was studied. The films were deposited by varying $O_2$gas flow rate with sputtering power and Ar gas flow rate of 200W and 60 sccm fixed. At the conditions of $O_2$ gas flow rate over 20 sccm, amorphous Tantalum oxide films with the refractive index of 2.1 and dielectric constant of 25 were deposited. Among those films, the capacitors dielectric properties of the film deposited at the condition of $O_2$ gas flow rate 50 sccm was best, the leakage current was 1$\times$10\ulcornerA/$\textrm{cm}^2$ at the electric field strength of 0.5 MC/cm and the breakdown field strength was over 2.0 MV/cm. This result could be explained from the analysis comparing with a standard sample using RBS because the composition of the film deposited at this condition was closest to the stoichiometric $Ta_2$O\ulcorner. The result of XPS analysis convinced that this film was stoichiometric $Ta_2$O\ulcorner film. A maximum cathode voltage was observed when $O_2$gas flow rate was 30 sccm. This shows that the Schiller's proposition that one can obtain stoichiometric films at the condition of maximum cathode voltage is not correct and more oxygen than that of the maximum voltage condition is necessary to deposit the stoichiometric Ta$_2$O\ulcorner films.

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