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Lee, Yun-Mi
- 건강소식
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- v.35 no.8
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- pp.12-13
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- 2011
기온이 높고 습한 여름이면 불면증이나 수면장애를 호소하는 사람이 많다. 또한, 스트레스, 불안감 등으로 인한 심리적인 이유로 밤에 잠 못 이루는 사람들도 많다. 수면을 위해 수면제를 먹는 것은 일시적인 도움은 될 수 있으나 수면제 장가복용으로 이어질 수 있다. 음주는 오히려 수면을 방해할 뿐이고 샤워를 하는 것도 수면에 방해될 뿐이다. 그렇다면 수면을 돕는 색채와 명화의 도움을 받아보는 것은 어떨까.
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Jeong, Chul Hee;Lee, Sang Woo
- Transactions of the Korean Society of Mechanical Engineers B
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- v.23 no.3
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- pp.419-430
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- 1999
Measurements of local blowing ratio and ammonia-diazo flow visualizations have been conducted for a shower-head film cooling on a first-stage turbine stator. In this study, six rows of normal holes are drilled symmetrically on the semicircular leading edge of a simulated blunt body. The measurements show that for an average blowing ratio based on freestream velocity, M, of 0.5, local average mass flow rate through the first two rows of the holes is less than those through the second and third two rows of the holes, and the fraction of mass flow rate through the first two rows to total mass flow rate has a tendency to increase with the increment of M. The flow visualizations reveal that the injection through the first two row results in inferior film coverage even In the case of M = 0.5, meanwhile the row of holes situated at farther downstream location provides higher film-cooling performances for all tested M. This is because film-cooling effectiveness depends on local mainflow velocity at the hole location as well as the mass flow rate through each row.
https://doi.org/10.22634/KSME-B.1999.23.3.419 인용 PDF

Jeong, Chul-Hee;Lee, Sang-Woo
- Transactions of the Korean Society of Mechanical Engineers B
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- v.24 no.2
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- pp.177-187
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- 2000
Measurements of temperature fields and film-cooling effectiveness have been conducted for a shower-head film cooling on the leading edge of a blunt body, which simulates a first-stage turbine stator. In this study, three injection cases are employed for an average blowing ratio based on freestream velocity, M, of 0.5, 1.0 and 1.5. Two (Case 1), four (Case 2) and six (Case 3) rows of normal holes are symmetrically drilled on the three tested circular-cylinder leading edges. The measurements show that regardless of M, the film-cooling effectiveness increases as the injection row is situated at farther downstream location. In Case 1, the film-cooling effectiveness is highest for M = 0.5 and lowest for M = 1.5. On the contrary, in Case 3, the film-cooling effectiveness is highest for M = 1.0 and lowest for M = 0.5. When M = 0.5, the film coverage by the first row of the injection holes deteriorates as the number of the injection row increases. In particular, the film-cooling effectiveness due to the injection through the first row of the holes in Case 3, has a nearly zero value.
https://doi.org/10.22634/KSME-B.2000.24.2.177 인용 PDF

Moon, Keun-Hwan;Oh, Ji-Sung;Cho, Jung-Tae;Lee, Jung-Pyo;Moon, Hee-Jang;Sung, Hong-Gye;Kim, Jin-Kon
- Proceedings of the Korean Society of Propulsion Engineers Conference
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- 2010.11a
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- pp.479-483
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- 2010
In this paper, a study for hybrid rocket combustion with cylindrical multi-port grain and swirl injector was performed to take advantage of regression rate. Change of the regression rate in the multi-port grain the placement of a swirl Injector experiments were performed. The results of multi-port grain using swirl injector were showed that the regression rate was increased compare with the shower head type injector.
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