• 한국도로학회논문집
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• 제17권5호
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• pp.67-73
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• 2015

PURPOSES : This study was conducted to derive the optimum mixing ratio of phosphorescent pigment for the development of phosphorescent line marking. METHODS: In this study, we utilized a literature review and case study methodology, to describe the domestic and foreign state of practice for the production and mixing of phosphorescent pigment for use in line marking. The optimal mixing ratio was derived by comparing the reduction in luminance over time for the various phosphorescent pigment mixing ratios identified in the literature. In addition, performance and construction characteristics were analyzed using field testing techniques. RESULTS : The results were as follows: 1) the results of the luminance performance standards tests showed that all of the phosphorescence test specimens satisfied the phosphorescent fire protection standard. As the phosphorescent pigment mixing ratio increased, the luminance value increased, 2) the luminance reduction rate was minimum at the mixing ratio of 50%. However, when compared to a mixing ratio 40%, a small difference was recorded, the luminance reduction rate from the mixing ratio of 40% is judged as being converged. Therefore, in view of the economic efficiency, it was determined that the optimal mixing ratio was 40%, 3) as a result of construction on the field, a mixing ratio of 40% was found to have a higher luminance value than the general line marking for up to three hours after sunset, 4) it was found that the phosphorescent line markings without glass beads spraying had a higher luminance value than the phosphorescent line markings with glass beads spraying. CONCLUSIONS : Through the results of the basic experiments of the line markings obtained by blending a phosphorescent pigment, the results could be applied to play an important role in the development of phosphorescent line marking paint technology and in establishing application planning for on-site construction characteristics.

• 대한기계학회논문집B
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• 제28권10호
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• pp.1178-1183
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• 2004

The purpose of this study was to investigate the influence of compression ratio on engine performance in a LPG(Liquefied Petroleum Gas) engine converted from a diesel engine. In ordor to determine the ideal compression ratio, a variable compression ratio 4-cylinder engine was developed. Retrofitting a diesel engine into a LPG engine is technically very complicated compared to a gasoline to LPG conversion. The cylinder head and the piston crown were modified to bum LPG in the engine. Compression ratios were increased from 8 to 10 in an increment of 0.5, the ignition timing was controlled to be at MBT(Minimum Spark Advance for Best Torque) for each case.

• 한국환경과학회지
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• 제18권6호
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• pp.595-601
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• 2009

The effects of the cation-to-anion resin ratio and bed depth on ion exchange performance of mixed-bed were studied at ultralow solution concentration. Breakthrough curves were experimentally obtained for NaCI solution as functions of resin ratio and bed depth. The bed depth affects the pattern of the sodium breakthrough curve but not the chloride breakthrough curve in beds because of the selectivity difference. Resin selectivity determines the shape of breakthrough curves, Some sodium and chloride breakthrough curves crossed at a point as a function of resin ratio. The lower cation-to-anion resin ratio showed the higher effluent concentration or treated volume of the crossover point regardless of the total resin weight.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.879-882
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• 1997

This paper aims to clarify the effect of the sol-gel sintered alumina grain and the PbO content of binder on the performance of the vitrified alumina stone for superfinishing the ball bearing race with the vitrified alumina superfinishing stone. The main conclusions obtained were as follows. The stone that contain 8- 11% PbO in binder shows the highest grinding ratio, and increasing or decreasing the PbO contents causes lower grinding ratio. When superfinishing with the stone using the 45% fused alumina and 55% sol-gel sintered alumina grain, the grinding ratio becomes the best, the other ratio of grain contents shows lower performance. With increasing the bending strength of stone, the grinding ratio becomes larger. The roughness of the finished surface is the lowest in case of using the stone of the above mentioned conditions.

• Structural Engineering and Mechanics
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• 제60권6호
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• pp.953-977
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• 2016

Modern performance-based design methods require ways to determine the factual behavior of structures subjected to earthquakes. Drift ratio demands are important measures of structural and/or nonstructural damage of the structures in performance-based design. In this study, global drift ratio and interstory drift ratio demands, obtained by nonlinear time history analysis of three generic RC frames using code-compatible ground motion record sets, are statistically evaluated. Several ground motion record sets compatible with elastic design spectra defined for the local soil classes in Turkish Earthquake Code are used for the analyses. Variation of the drift ratio demands obtained from ground motion records in the sets and difference between the mean of drift ratio demands calculated for ground motion sets are evaluated. The results of the study indicate that i) variation of maximum drift ratio demands in the sets were high; ii) different drift ratio demands are calculated using different ground motion record sets although they are compatible with the same design spectra; iii) the effect of variability due to random causes on the total variability of drift ratio demands is much larger than the effect of variability due to differences between the mean of ground motion record sets; iv) global and interstory drift ratio demands obtained for different ground motion record sets can be accepted as simply random samples of the same population at %95 confidence level. The results are valid for all the generic frames and local soil classes considered in this study.

• 디지털융복합연구
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• 제10권2호
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• pp.73-82
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• 2012

본 논문은 중소기업을 대상으로 재무구조가 기업의 경영성과에 미치는 영향에 대하여 연구함을 목적으로 한다. 이를 위해 경인지역 소재 중소기업 562개 업체를 대상으로 '09년 비유동자산구성비율, 기업규모 및 부채비율을 각각 독립변수로, 매출액영업이익률 및 자기자본순이익률을 각각 종속변수로 정하여 이들의 상관관계를 실증적으로 분석하였는바, 전반적으로 재무구조는 경영성과에 긍정적인 영향을 미치는 것으로 분석되었다.

• 한국자동차공학회논문집
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• 제11권6호
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• pp.1-6
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• 2003

The engine performance and combustion characteristics of methanol blended fuel in a multiple-point electronic control gasoline engine were discussed on the basis of experimental investigation. The effects of methanol blending fuel on combustion in cylinder were investigated under various conditions of engine cycle and blending ratio. The results showed that the engine performance was influenced by the methanol blended ratio. The results showed that the engine performance was influenced by the methanol blending ratio and the variations of operating conditions of test engine. The increase of blended fuel brought on the improvement of emission characteristics such as THC, CO, and NOx concentration. The effect of methanol blended fuel on the fuel consumption rate and the other characteristics of performance were discussed.

• 대한전기학회논문지:전력기술부문A
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• 제54권8호
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• pp.401-409
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• 2005

This paper describes a feasibility analysis result of STATCOM application for the Jeju-Haenam HVDC system. The Jeju-Haenam HVDC system is one of the typical HVDC system interconnected with the low short-circuit-ratio AC system, which is vulnerable to the commutation failure due to the AC voltage variation. STATCOM has been considered as an effective reactive-power compensator to increase short-circuit-ratio of the interconnected AC system. In this study, a simulation model of Jeju-Hacnam HVDC system with STATCOM was developed using PSCAD/EMTDC. The developed simulation model was utilized to analyze the dynamic performance analysis of Jeju-Haenam HVDC system with STATCOM. The analysis results show that STATCOM can improve the dynamic performance of Jeju-Haenam HVDC system, such as load-change recovery performance and fault recovery performance.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 춘계학술대회 논문집
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• pp.320-323
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• 2009

추진기관의 개발과정에서는 추진제의 조성개발, 온도에 따른 성능분석, 내열재 삭마상태 등 여러가지 고려사항이 있다. 노즐 확장비에 따른 추진기관의 성능분석 또한 이러한 과정 중에 하나로 추진기관의 성능을 결정짓는 중요한 요소이다. 추진기관에 대한 해석 후 실제 모타를 제작 시험하여 이를 검증하였다.

• 동력기계공학회지
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• 제17권1호
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• pp.58-63
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• 2013

The aerodynamic performance of double inlet sirocco fan is strongly dependent upon the design factors of impeller and scroll. In this paper, the change of scroll size was adopted to investigate the aerodynamic performances of double inlet sirocco fan and indoor PAC. Especially, a scroll expansion angle and a cut-off clearance ratio were considered to change the scroll size. In addition, the installation depth between double inlet sirocco fan and indoor PAC was considered. As a result, the total pressure efficiency of double inlet sirocco fan shows about 62%~73% according to the change of scroll expansion angles. Moreover, the flowrate performance of indoor PAC is the best at the condition of a scroll expansion angle of 8°, an installation depth of 15 mm and a cut-off clearance ratio of 8%.