• 한국방사선학회논문지
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• 제9권7호
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• pp.467-471
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• 2015

본 연구에서는 L-tube insertion 환자의 흉부 AP 검사 시 tube tip이 환자의 자세나 방사선 조사각에 의해 왜곡되는 정도를 파악하고 정확한 임상정보를 제공하기 위해 검사 시 정확한 tube 각도를 유지하여 영상의 질을 높이고자 하는데 있다. 실험 장비로 SHIMADZU사의 ELMO-T6S를 사용하였으며, Chest phantom의 표면에 1 mm 간격의 눈금격자를 부착한 L-tube를 부착하여 실험을 하였다. 실험영상의 영상 획득 조건은 90 kVp, 4 mAs, SSD 120 cm로 하여 영상을 획득하였다. Phantom position은 table에서 supine, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$로 변화시키고 각 position마다 Head 방향과 Feet 방향으로 수직, ${\pm}5^{\circ}$, ${\pm}10^{\circ}$, ${\pm}15^{\circ}$ 촬영을 하여 영상을 획득하였다. 본 실험 결과로 L-tube tip의 위치는 환자의 자세와 방사선 입사각에 따라 달라지며 환자의 position이 30, 45, $60^{\circ}$일 때 보다 supine 일 때 tip의 위치변화가 적은 것으로 나타났다. 흉부 방사선 검사를 통해 L-tube tip의 정확한 위치를 보고자 할 때 잘못 된 입사각에 의한 영상의 왜곡이 발생하지 않도록 환자의 자세나 입사각을 조정해야 하며, 해당 시술을 확인하는데 정확한 평가 지표로 이용될 수 있도록 임상에서 업무를 수행하는 방사선사들의 세심한 노력이 필요할 것으로 사료된다.

• 한국기계가공학회지
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• 제12권5호
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• pp.149-156
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• 2013

The performances of solar collectors with single and double evacuated tube were experimentally compared. The solar collector with single evacuated tube using surface treatment in this study consists of radiation fin, heat pipe, absorber plate, glass tube, cap and regulating valve, and so on. Surface treatment was conducted for heat pipe and absorber plate with black chrome plating and copper black coating. As the results, the performance of solar collector with single evacuated tube using surface treatment showed good results compared that of double evacuated tube. Absorber plate played a positive role in performance and showed increase of about 28%. Further performance depends on vacuum degree and vacuum degree has to be considered economical efficiency in solar collector.

• 설비공학논문집
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• 제11권6호
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• pp.808-814
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• 1999

Pool boiling performance of a metal-formed enhanced tube for a flooded refrigerant evaporator was experimentally investigated. Tests were performed for three different refrigerants(R-11, R-123, R-l34a), at two different saturation temperatures $4.4^{\circ}C \;and \;26.7^{\circ}C$ .Heat flux was varied from 10㎾/$m^2\;to\ 50㎾/$m^2$. Compared with the heat transfer coefficients of the smooth tube, the heat transfer coefficients of the enhanced tube were 6.6 times higher for R-11, 6.0 tines higher for R-123 and 3.5 times higher for R-l34a. The enhancements are comparable with those of foreign products. The heat transfer coefficients of R-l34a were higher than those of R-11 and R-123, either for the enhanced tube or for the smooth tube. At $4.4^{\circ}Csaturation temperature, however, the heat transfer coefficients of R-l34a were approximately the same as those of R-11, The effect of the saturation pressure on the boiling performance was similar to that of the smooth tube - the heat transfer coefficient increases as the saturation pressure increases.

• International Journal of Air-Conditioning and Refrigeration
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• 제8권2호
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• pp.23-28
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• 2000

In this study, pool boiling performance of a structured enhanced tube for a flooded refrigerant evaporator was experimentally investigated. Tests were performed for three different refrigerants(R-11, R-123, R-l34a). Compared with the heat transfer coefficients of the smooth tube, the heat transfer coefficients of the enhanced tube were 6.6 times larger for R-11, 6.0 times larger for R-123 and 3.5 times larger for R-l34a, which are comparable with the performance of foreign products. The heat transfer coefficients of R-l34a was higher than those of R-11 or R-123, both for the enhanced tube and for the smooth tube. At 4.4$^\circ$C saturation temperature, however, the heat transfer coefficients of R-l34a was approximately the same as those of R-11. The effect of the saturation pressure on the boiling performance was similar to that of the smooth tube-the heat transfer coefficient increased as the saturation pressure increased.

• 설비공학논문집
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• 제10권5호
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• pp.569-580
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• 1998

In this study, condensation heat transfer coefficients(HTCs) of a plain tube, low fin tube, and Turbo-C enhanced tube for CFC-11, HCFC-123, CFC-12, HFC-l34a are measured and compared against each other. All data are taken at the vapor temperature of 39$^{\circ}C$ with a wall subcooling temperature 3~8$^{\circ}C$. Test results show that HTCs of a low vapor pressure refrigerant, HFC-123, for a plain, low fin, and Turbo-C tubes are 10.5~20.5%, 8.2~12.2%, 16.5~19.2% lower than those of CFC-11, respectively. On the other hand, HTCs of a medium vapor refrigerant, HFC-l34a, for a plain, low fin, and Turbo-C tubes are 20.6~31.8%, 0.0~8.0%, 13.2~20.9% higher than those of CFC-12, respectively. For all refrigerants tested, HTCs of Turbo-C tube are the highest among the three tubes showing almost 8 times increase in HTCs as compared to those of a plain tube. Nusselt's prediction equation for a plain tube yielded 12% deviation for all plain tube data while Realty and Katz's prediction equation for a low fin tube yielded 20% deviation for all low tube data.

• 한국자원식물학회지
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• 제3권2호
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• pp.123-128
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• 1990

In every reciprocal crosses of self pollination, interspecific pollination through ordinary stigma pollination of L. longiflorum and $L.{\;}{\times}{\;}elegans$, pollen vigorously germinated in stigma, and pollen tube was growing. But, 5 days after pollination, pollen tube stopping their growth in the same style as was observed in the cross of self pollination and interspecific pollination. Intrastylar pollination of $L.{\;}{\times}{\;}elegans$ and L. longiflorum passed stylar cannal through the basal part of styles. But, pollen tube that was growing to the ovule of the ovary was extremely small. In morphogical observation of ovary 10 days after pollination, it was observed, that every reciprocal crosses of L. longiflorum ${\times}$ L. ${\times}$ elegans was fertilized through intrastylar pollination, so that this technique was used to overcome cross incompatibilities.lities.

• 한국표면공학회지
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• 제41권1호
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• pp.38-42
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• 2008

316L stainless steel welding tube was electrolytically polished and the inner surface characteristics of the tube were tested. Electro-polishing variables such as current, voltage, concentration of electrolyte and electropolishing time were changed to seek for optimum condition. These makes a optimum conditions for the electro-polishing as 4000 A, 9 V, 1.7 specific gravity of electrolyte, and 30 minute of electro-polishing time. It makes the surface roughness as Ra < $0.25{\mu}m$. XPS test resulted as the ratio of CrO/FeO equals or more to 3/1. AES test resulted as the thickness of CrO film of $38{\AA}$. DTA test resulted as the tube did not react with $N_2,\;H_2\;and\;O_2$ gas below 1073K. As summarize above results, the electro- polished 316L stainless steel welding tube satisfied the conditions to apply as a pipeline for semi- conductor production facility and clean room.

• 대한기계학회논문집B
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• 제29권7호
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• pp.854-860
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• 2005

Pool boiling heat transfer characteristics of R-134a were investigated in titanium plain and low finned tubes. The diameter of test tube was 15.88 mm and the fin density was 33 fpi. Tests were conducted at saturation temperatures of $20^{\circ}C$ and $30^{\circ}C$. Heat fluxes varied from 5000 W/$m^2$ to 50,000 W/$m^2$ based on surface area of the plain tube. The pool boiling heat transfer coefficients of the titanium horizontal plain tube are lower than those of the copper plain tube by $8.2\%$. The boiling heat transfer coefficients of the low finned tube are averagely higher than those of the plain tubes by $34\%$. The average deviation of the Slipcevic correlation from the present data for the low finned tube is $20\%$.

• 설비공학논문집
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• 제3권4호
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• pp.222-230
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• 1991

Conjugate heat transfer by steady laminar natural convection from a conducting tube with two vertical axial fins has been studied by a finite difference numerical procedure under basic conditions; $Ra=10_6$, Pr = 5 and $L_F=0.15$. The maximum local tube Nusselt number appears at ${\theta}=140^{\circ}$ for $L_F=0.06$, at ${\theta}=130^{\circ}$ for $L_F=0.30$ and at ${\theta}=120^{\circ}$ for $L_F=0.30$, $L_F=0.06$, respectively. The maximum mean Nusselt number shows at $L_F=0.18$ for the downward fin and at $L_F=0.12$ for the upward fin. Therefore the optimized fin length is $L_F{\approx}0.15$ under these conditions. At $L_F=0.15$, the mean Nusselt number by increasing Rayleigh number is remarkably increased for downward fin and then is slowly increased except for downward fin, it by increasing Prandtl number is apparently increased at $Pr{\leq}2$, and slightly increased at Pr>2.

• 성인간호학회지
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• 제13권1호
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• pp.136-147
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• 2001

Dysphagia is common and serious problem in intracerebral hemorrhage patients. Nasogastric-tube intubation is an important method for dysphagic patients who have an intracerebral hemorrhage. But many discomforts develope in patients with a nasogastric-tube. Therefore, it is necessary to decide when to remove the tube and as early as possible. The purpose of this study is to decide the applying time of training program to facilitate deglution for dysphagic patients who have intracerebral hemorrhage. Among the 343 patients with intracerebral hemorrhage who had been admitted to P-university hospital from April, 1994 to December, 1998, the medical record of the 110 patients with nasogastric tube were reviewed retrospectively. Results from the study were as follows: 1. Nasogastric tube insert duration of improved patients was a mean of 23.2 days 2. When a L-tube was inserted and removed, the L.O.C. of improved patients was $2.6{\pm}0.8$(in the midst of stupor or a semicoma),$1.9{\pm}0.5$(close to drowsy), respectively. This was signifcantly different(P=0.000). 3. When a L-tube was inserted and removed, GCS of improved patients was $9.3{\pm}2.9$, $12.1{\pm}2.2$ respectively. This was significantly different (P=0.000). 4. The duration of nasogastric tube insertion was the longest when in a stupor(L.O.C), 6~8 points(GCS).