원관 주위의 대류 열전달에 대한 원둘레 방향의 열전도의 영향

이승홍,이억수,정은행 釜山大學校生産技術硏究所 1997 生産技術硏究所論文集 Vol.53 No.-

원관축의 수직방향으로 유체가 유동하는 경우에, 가열되는 수평 원관 주위에서 원둘레 (θ)방향으로 비대칭적으로 균일하지 않게 온도가 분포하기 때문에 원둘레 방향으로의 전도 열전달이 존재하고 비균일 대류 열전달 현상이 생긴다. 본 연구에서는 공기와 물을 작동유체로 하고 직교 유동내에 있는 수평 원관의 열전달 실험에서 국소 대류 열전달에 대한 원둘레 방향 열전도의 영향에 대하여 연구하였다. 에너지 방정식에서 유도된 무차원 수가 반경방향에 대한 원둘레 방향의 열전도의 영향을 나타내는 무차원 수로 사용되었다. 4가지 모델을 직접 전기저항 가열방식으로 가열하고, 원관 표면의 온도를 직접 측정하여 2차원 온도분포의 경계조건으로 사용하여 원관의 단면 내부에서 2차원 온도분포 T(r,θ) 를 보여준다. With uniform heat generation in a horizontal cylindrical heater placed in a cross flow boundary condition, heat flow that is conducted along the wall of the heater creates a non-isothermal surface temperature and heat flux distribution. In the present investigation, the effects of circumferential wall heat conduction on convection heat transfer is investigated for the case of forced convection around horizontal cylinder in cross flow of air and water. Non-dimensional conjugation parameter which can be deduced from the governing energy differential equation should be used to express the effect of circumferential wall conduction heat transfer. Two-dimensional temperature solutions T(r,θ) distribution is presented. The influence of circumferential wall heat conduction is demonstrated on graph of local Nusselt number.

원관 주위의 전도 열전달과 공기의 대류 열전달

이승홍,이억수 釜山大學校生産技術硏究所 1997 生産技術硏究所論文集 Vol.52 No.-

가열되는 원관에 대하여 수직방향에서 공기가 유동할 경우, 원관의 주위 온도를 측정, 분석함으로서, 원관 주위의 강제 대류 열전달에 대한 원주(θ)방향으로 전도 열전달의 영향을 연구하였다. 실린더의 내벽에서 일정한 열유속을 반경(r)방향으로 공급하면, 대류에 의한 원형 실린더 주위의 비대칭적인 온도분포 때문에, 열은 전도에 의해서 원관을 통하여 원주(θ)방향으로 전도 열전달이 존재하고, 실린더 주위로 대류에 의한 대류 열전달이 동시에 일어난다. 기하학적으로 유사한 표면과 경계조건에 대해서, 전도 열전달율은 원관의 열전도계수와 두께에 의존하고 그리고 고체 원관의 벽면을 통하여 발생하는 전도 열전달이 대류 열전달에 미치는 영향은 유체의 열전도계수와 반경의 크기에도 영향을 받는다. 복합 무차원 계수 가 원주방향의 전도 열전달의 대류 열전달에 관한 영향을 나타내는 계수로 사용되었다. 국소 열전달율과 국소 대류 열전달계수에 대한 원주방향의 전도 열전달의 영향은 복합 무차원계수 K*가 작을 경우에 매우 큰 영향을 주고 있음이 발견되었다. The influence of circumferential wall heat conduction on convection heat transfer is investigated for the case of forced convection around a circular tube in cross flow of air by measurements of surface temperature of circular tubes. Keeping uniform heat generation from the inner surface of the cylinder in radial direction, heat is transferred by wall conduction in the circumferential (θ) direction due to the asymmetric nature of the temperature distribution of the cylinder and by convection around the perimeter of the cylinder simultaneously. The wall heat conduction rate depends on conductivity of the tube and size of the tube thickness and the effect of wall conduction on convection heat transfer also depends on conductivity of the fluid and size of the tube radius for geometrically similar surfaces and cross flow conditions. A non-dimensional conjugation parameter has been used to express the effect of the circumferential wall heat conduction. The significant effects of wall conduction on the local convective heat transfer rate and local convective heat transfer coefficients around a circular tube is found when value of the conjugation parameter k* becomes smaller.

수평평판의 층류 막응축에서 압력의 영향

이억수(Euk-Soo Lee),이승홍(Sung-Hong Lee) 대한기계학회 2008 大韓機械學會論文集B Vol.32 No.12

Laminar film condensation of saturated vapor in forced flow over a flat plate is analysed. The problem is formulated as exact boundary-layer solution and integral approximate solution. From numerical solutions of the governing equations, it is found that the energy transfer by convection and the effect of inertia term in the momentum equation in negligibly small for low pressure but quite important for high pressure. The condensate rate, liquid-vapor interfacial shear stress and local heat transfer are strongly dependent on the reduced pressure Pr and the modified Jacob number Ja/Pr.

PDT 말뚝용 모르타르의 개발 및 현장적용

허억준(Hur, Euk Jun),신병우(Shin, Byung Woo),채수근(Chai, Soo Geun),김성수(Kim, Seong Soo) 한국콘크리트학회 2007 한국콘크리트학회 학술대회 논문집 Vol.2007 No.5

22q11 Deletion Syndrome을 동반한 정신분열병 1예

방수영,김창윤,주연호,서을주,유한욱 大韓神經精神醫學會 2003 신경정신의학 Vol.42 No.4

It has been well known that 22q deletion syndrome (22qDS), encompasses several genetic syndromes associated with microdeletions at chromosome 22q11.2 became relatively generally identified in the 1990s through the availability of specialized chromosomal studies, and it includes such syndromes as velocardiofacial syndrome (VCFS), DiGeorge syndrome (DGS), Shprintzen syndrome, CATCH 22. The syndrome is characterized by distinctive dysmorphology, congenital heart disease, athymia, parathyroid disease, other congenital diseases, learning difficulties and various psychiatric illnesses. This syndrome is a common genetic condition often accompanied by mild cognitive impairment. Learning difficulties and anger outburst are also common in adolescence with this syndrome, In addition, a prevalence of major psychiatric disorders in adults' individuals are high, especially schizophrenia, schizoaffective disorder, bipolar disorder and other psychiatric illnesses, including simple or social phobia, depression, obsessive-compulsive disorder. We report a patient with facial dysmorphology, cleft lip and palate, ventricular septal defect, borderline IQ, poor impulse control and psychotic symptoms who was diagnosed schizophrenia and 22qDS by FISH analysis which finds 22q11.2 microdeletion.

Synthesis and characterization of heteroleptic titanium MOCVD precursors for TiO₂ thin films

Kim, Euk Hyun,Lim, Min Hyuk,Lah, Myoung Soo,Koo, Sang Man The Royal Society of Chemistry 2018 Dalton Transactions Vol.47 No.7

<P>Heteroleptic titanium alkoxides with three different ligands, <I>i.e.</I>, [Ti(O<SUP>i</SUP>Pr)(X)(Y)] (X = tridentate, Y = bidentate ligands), were synthesized to find efficient metal organic chemical vapor deposition (MOCVD) precursors for TiO2 thin films. Acetylacetone (acacH) or 2,2,6,6-tetramethyl-3,5-heptanedione (thdH) was employed as a bidentate ligand, while <I>N</I>-methyldiethanolamine (MDEA) was employed as a tridentate ligand. It was expected that the oxygen and moisture susceptibility of titanium alkoxides, as well as their tendency to form oligomers, would be greatly reduced by placing multidentate and bulky ligands around the center Ti atom. The synthesized heteroleptic titanium alkoxides were characterized both physicochemically and crystallographically, and their thermal behaviors were also investigated. [Ti(O<SUP>i</SUP>Pr)(MDEA)(thd)] was found to be monomeric and stable against moisture; it also showed good volatility in the temperature window between volatilization and decomposition. This material was used as a single-source precursor during MOCVD to generate TiO2 thin films on silicon wafers. The high thermal stability of [Ti(O<SUP>i</SUP>Pr)(MDEA)(thd)] enabled the fabrication of TiO2 films over a wide temperature range, with steady growth rates between 500 and 800 °C.</P>

ds RNA 추출방법에 의한 원내감염 원인균으로서의 Rotavirus의 가능성조사

서억수,이상화,설성용,조동택 慶北大學校 醫科大學 1989 慶北醫大誌 Vol.30 No.4

Rotavirus에 의한 급성 장염이 원내감염에 의하여 유발될 수 있는가를 조사하기 위하여 D병원 소아과에 1989년 10월에 각종의 질병으로 입원한 61명으로부터 대변을 채취하여 적정수의 검체가 모이면 rotavirus의 double stranded RNA를 추출하여 agarose로 전기영동을 하였다. 임상적 진단에 의해 human rotavirus 감염증으로 인한 장염으로 판명된 입원환자 7명중 3명으로부터 rotavirus 특유의 dsRNA genome을 검출할 수 있었다. 초기진단이 rotavirus 감염증과 무관한, 폐렴을 주소로 입원한 생후 10개월된 환자에서도 rotavirus genome을 입원후 6일째 3회 설사한 변에서 검출할 수 있었다. 이 환자가 입원한 병실은 rotavirus로 인한 장염으로 입원한 환자들이 동일 병실에 수용된 적이 있었다. 초기 임상진단과 rotavirus의 발병에 이르는 잠복기를 감안할 때 이 경우는 rotavirus가 원내감염의 원인균이 되었음을 강력히 시사한다. For the study of molecular epidemiology of ratovirus as a possible agent on nosocomial infections, a total of 61 stool specimen was obtained from patients with various kinds of diseases who were admitted to the pediatric ward at a teaching Hospital during October, 1989. The stool specimens were tested throught the method of the extraction of ds-RNA followed by agarose gel electrophoresis. We could detect the rotavirus specific ds-RNA genomes from the three stool sepciments among 7 patients whose clinical diagnosis were human rotavirus gastroenteritis. A 10 month-old infant whose primary diagnosis was pneumonia and unrelated to the rotavirus infection developed three episodes of diarrhea at the 6th admission day, and rotavires genomes were also detected from the diarrheal specimen. This infant was admitted to the same room where the patients with human rotavirus gastroenteritis had admitted previously. Considering the clinical diagnosis at admission and incubation period of the rotavirus gastroenteritis, this case of rotavirus infection strongly suggested a typical nosocomial infection.

C-BAND WLAN용 SiGe HBT MMIC 이중평형형 상향주파수 혼합기

서정욱(Jung-Euk Seo),정병희(Byung-Hee Jung),오영수(Young-Soo Oh),채규성(Kyu-Sung Chae),김창우(Chang-Woo Kim) 대한전자공학회 2003 대한전자공학회 학술대회 Vol.2003 No.7

평판의 층류 막응축에서 복합열전달에 대한 근사해

이억수,Lee Euk-Soo 한국마린엔지니어링학회 2005 한국마린엔지니어링학회지 Vol.29 No.5

Liquid film thickness in laminar film condensation for flow over a flat plate generally is so thin that both fluid acceleration and thermal convection within the liquid film can be neglected. An integral solution method is proposed to solve the conjugate problems of laminar film condensation and heat conduction in a solid wall. It is found that approximate solutions of the governing equations involve four physical parameters to describe the conjugate heat transfer problem for laminar film condensation. It is shown that the effects of interfacial shear. mass transfer and local heat transfer are strongly dependent on the thermo-physical properties of the working fluids and the Jacob number.

전기자동차 모터구동용 전력변환장치(PCU) 설계 및 구현

김말수(Mal-Soo Kim),김승모(Seung-Mo Kim),허남억(Nam-Euk Huh),오승진(Seung-Jin Oh),남광희(Kwang-Hee Nam) 전력전자학회 2012 전력전자학술대회 논문집 Vol.2012 No.11