고레이놀즈수 유동 장치에서 Y형 이음의 유동 특성

박용철(Y.C. Park),윤현기(H.G. Yoon),서경우(K.W. Seo),지대영(D.Y. Chi),윤주현(J.H. Yoon) 한국전산유체공학회 2012 한국전산유체공학회 학술대회논문집 Vol.2012 No.5

In nuclear power plant, the reactor cooling system has maintained high-Reynolds-number flow above 1E+07 to cool a heat generated by the reactor. To minimize uncertainty for flow calibration, it is necessary to install a flow simulation system to maintain the high-Reynolds-number flow. Y-connection is selected to connect four (4) parallel high flow circulation pumps for minimizing system pressure loss. This paper describes the characteristics for Y-connection by computer flow simulation. It was confirmed through the results that the pressure loss of the Y-connection was lower than that of T-connection, and that the pressure loss of the connection was similar sixty degree (60°) and below of connection angle.

Analysis of Power Generation Efficiency and GHG Reduction Effect by Application of Low Temperature Catalyst and High Efficiency Dry Flue Gas Treatment System

( Y. S. Yoon ),( J. S. Bae ),( E. H. Kwon ),( H. Y. Park ),( T. W. Jeon ),( Y. K. Lee ) 한국폐기물자원순환학회(구 한국폐기물학회) 2018 한국폐기물자원순환학회 춘계학술발표논문집 Vol.2018 No.-

To achieve energy efficiency improvement is used to lower temperature for emission gas at catalyst inlet, or to reduce/stop using steam to reheat emission gas. Saved energy from this process can be used as power source in order to increase generation efficiency. Dry emission gas treatment, on the other hand, is the technology to increase generation efficiency by using highly efficient desalination materials including highly-responsive slaked lime and sodium type chemicals in order to comply with air pollution standards and reduce used steam volume for reheating emission gas. If dry emission gas is available, reheating is possible only with the temperature of 45℃ in order to expect generation efficiency by reducing steam volume for reheating. Retention energy of emission gas from combustion is calculated by emission gas multiplied by specific heat and temperature. In order to obtain more heat recovery from combustion emission gas, it is necessary to reduce not only exothermic loss from boiler facilities but emission calorie of emission gas coming out of boiler facilities. In order to reduce emission calorie of emission gas, it is efficient to realize temperature lowering for the emission gas temperature from the exit of heat recovery facility and reduce emission gas volume. When applying low temperature catalysts, the energy saving features from 0.03% to 2.52% (average 1.28%). When increasing the excess air ratio to 2.0, generation efficiency decreases by 0.41%. When the inlet temperature of the catalyst bed was changed from 210℃ to 180℃, greenhouse gas reduction results were 47.4, 94.8, 118.5, 142.2 thousand tons-CO₂/y, CH₄ was calculated to be 550.0, 1100.1, 1375.1, 1650.1 kg-CH₄/y, and N₂O was 275.0, 550.0, 687.6, 825.1 kg-N₂O/y. In the case of high efficiency dry flue gas treatment, reduction of greenhouse gases by the change of temperature 120~160℃ and exhaust gas 5,000 ~ 6,500 m³/ton is possible with a minimum of 355,461 ton/y of CO₂ and minimum 4,125 tons of CH₄/y to a maximum of 6,325 ton/y and N₂O to a minimum of 2,045 kg/y to a maximum of 3,135 kg/y.

200 GeV/핵자 유황이온과 핵건판핵의 충돌에 의해 생성된 헬륨 파쇄핵의 극한파쇄 연구

김동철,송진섭,윤천실,정성헌,박인곤,김종오,김철수,김태연,이승희,조재희,천병구,김재률,김준원,김태익,박명렬,장한일,임인택 慶尙大學校 기초과학연구소 1992 基礎科學硏究所報 Vol.8 No.-

고에너지 중이온 원자핵과 핵건판의 충돌에서, 200GeV/핵자 유황이온에 의해 생성된 파쇄 헬륨핵(Z=2)의 실험실계의 방출각 분포는 표적핵에 무관한 회귀공식. dN=exp[a+k exp(η-y_b)]d[exp(η-y_b)]로 잘 표현된다. 여기에서 의사신속도 η=-ln[tan(θ/2)]이고, y_b는 실험실계의 입사입자(^32S)의 신속도이다. 이 공식에 의한 적합에서 k=-0.057±0.008로 얻어진다. 즉, 핵건판과 고에너지 중이온의 충돌에서 파쇄 헬륨핵의 exp(η-y_b)의 분포는 "극한파쇄" 현상을 잘 설명하고 있다. The angular distribution of emission angle θ of helium (Z=2) produced in the collisions of incident particles of 200 GeV/nucleon ^32S in nuclear emulsion is well expressed by dN=exp[a+k exp(η-y_b)]d[exp(η-y_b)] where the pseudorapidity is η=-ln[tan(θ/2)], the laboratory system primary rapidity is y_b, and k=-0.057+0.008. The shape of this frequency of occurrence distributions in terms of exp(η-y_b) attests to the validity of the concept of "limiting fragmentation" for helium projectile fragments produced in the projectile fragmentation regions of heavy ion collisions in nuclear emulsion.

Zn ion의 영향에 따른 $(Y,\;Zn)_2O_3$:$Eu^{3+}$ 적색 형광체의 발광특성

송영현,문지욱,박우정,윤대호,Song, Y.H.,Moon, J.W.,Park, W.J.,Yoon, D.H. 한국결정성장학회 2008 한국결정성장학회지 Vol.18 No.6

본 연구에서는 자외선 영역에서 발광하는 우수한 특성의 적색 형광체를 얻기 위하여 고상 반응법으로 air 분위기에서 $1200^{\circ}C$에서 6시간 동안 열처리하여 $(Y,\;Zn)_2O_3$:$Eu^{3+}$를 Zn 이온의 농도 변화에 따라 실험하였다. $(Y,\;Zn)_2O_3$:$Eu^{3+}$를 XRD에 의해 비교 분석한 결과 주요 peak들이 JCPDS card(No. 41-1105)와 거의 일치하는 것을 확인하였다. 그러나 Zn 이온치 농도가 5 mol% 이상일 때 XRD에서 ZnO의 peak이 관찰되는 것을 확인 하였다. 이로 인하여 Zn 이온의 농도가 5 mol% 이하일 때 불순물 상 없이 $Y_2O_3$ 구조에 잘 고용되는 것을 확인하였다. $(Y,\;Zn)_2O_3$:$Eu^{3+}$의 발광 peak은 여기 흡수 영역인 ${\lambda}ex=254\;nm$를 기준으로 612 nm 영역에서 $Eu^{3+}$ 이온의 $^5D_0{\rightarrow}^7F_2$에 전형적인 에너지 천이에 의해 가장 강한 발광 peak을 나타내는 것을 확인하였으나 Zn 이온의 농도가 10 mo1% 이상일 때 갑자기 발광 peak이 현저히 감소하는 것을 확인하였고 최대의 발광 peak을 가질 때 형광체의 조성은 $(Y_{0.95},\;Zn_{0.05})_2O_3$:$Eu^{3+}_{0.075}$이였고 입자 size는 $0.4{\sim}3{\mu}m$로 확인되었다. To enhance the luminescence properties, the red phosphor composed of $(Y,\;Zn)_2O_3$:$Eu^{3+}$ as doping concentration of Zn ion is synthesized at $1200^{\circ}C$ for 6 hrs in air atmosphere by conventional solid reaction method. As a result of the red phosphor $(Y,\;Zn)_2O_3$:$Eu^{3+}$ is measured X-ray diffraction (XRD), The main peak is nearly corresponded to the same as JCPDS card (No. 41-1105). When the doping concentration of Zn ion is more than 5 mol%, However, the ZnO peak is showed by XRD analysis. Therefore, when the doping concentration of Zn ion is less than 5 mol%, the Zn ion is well mixed in $Y_2O_3$ structure without the impurity phases. The photoluminescence (PL) properties is shown as this phosphor is excited in 254 nm region and the highest emission spectra of $(Y,\;Zn)_2O_3$:$Eu^{3+}$ has shown in 612 nm region because of a typical energy transition ($^5D_0{\rightarrow}^7F_2$) of $Eu^{3+}$ ion. As the doping concentration of Zn ion is more than 10 mol%, the emission peak is suddenly decreased. when the highest emission peak as doping concentration of Zn ion is shown, the composition of this phosphor is $(Y_{0.95},\;Zn_{0.05})_2O_3$:$Eu^{3+}_{0.075}$ and the particle size analyzed by FE-SEM is confirmed from 0.4 to $3{\mu}m$.

1987년 한국에서 발생한 렙토스피라병의 혈청역학적 조사

이증훈,박영수,이우곤,김석용,정선식,우준희,박성광,박경희,송영욱,김선영,기정일,최두혁,강성귀,김주완,최강원,김우열,최명식,최인학,장우현,윤성열 대한감염학회 1988 감염 Vol.20 No.3

Human leptospirosis was an unfamiliar disease in Korea until 1984 that outbreak of leptospirosis occurred among farmers and soldiers after field works for harvesting rice. During that time, Lee and Jo confirmed the first Korean cases of leptospirosis by serological test, isolation of causative agent and autopy findings. Afterward several outbreaks occurred also during autumn especially after flood in every years and some characterisitcs of leptospirosis in Korea such as clinical manifestations, serotypes and seroepidemiological features has been revealed by many investigators. Because of the major mode of transmission between rodents and human is by direct contact with leptospiral urine of rodents or contaminated soil by the urine, leptospirosis in Korea has been primarily a disease of person in occupations heavily exposed to contaminated soil or infected urine such as farmer, army and etc. Therefore it seems that leptospirosis is one of the main communicable diseases to be controlled urgently in Korea, for an agricultural people account for almost half of total Korean people. For clarifying the seroepidemiological patterns of human leptospirosis in Korea by sex, month region and main reacting serovars of L. interrogans among acute febrile disease occurred in 1987, 1,773 patient's sers with acute febrile episodes were tested by microagglutination test using 19 representative strains of leptospiral serogroup as antigen. All of those sera were collected from 10 collaborative clinics located in Kyunggi, Kangwon, Chungbuk, Chungnam, Chonbuk, Chonnam province and Seoul. The results wee summerized as follows. 1) Among 1,773 sera of patients with acute febrile episodes, 219 (12.4%) were seropositive to L. interrogans, 487(27.5%) to R. tsutsugamushi, 241(13.6%) to R.typhi and 160(90.0%) to Hantaan virus. 2) Among seropositives to L.interrogans, the male outnumbered the female, 65% and 35%. 3) For age distribution, 26.9% of seropositives to L.interrogans were fifties, 19.6% were forties, 9.1% were sixties, 5.9% were thirties and 4.1% were twenties. 4) Eighty three percent of seropositives had occurred between September and October in 1987 with a peak in September. 5) Main leptospiral serovars reactive to patient's sera were Icterohaemorrhagiae(54.3%), Canicola(31.0%), CH-48(13.2%), Tarassovi(0.9%)and Cynopteri(0.5%). 6) For regional distribution, 65.8% of seropositives to L.interrogans were residents from Chonbuk, 12.3% were Chonnam, 7.3% were Chungnam, 5.5% were Kyunggi and 1.4% were Kangwon.

Intracellular Pools of Inositol Phosphates in NIH3T3 Cells Damaged with UV Light

Yoon, Y S,Shin, I C,Joe, C O,Kang, K W 한국유전학회 1990 Genes & Genomics Vol.12 No.4

The relationship between inositol phosphates metabolism and inhibition of DNA synthesis was examined. The DNA synthesis rate measured by the ³H-labeled thymidine incorporation into cellular DNA in NIH3T3 fibroblast treated with UV indicates that there exists a resting stage of DNA synthesis in cells exposed to UV light. Intracellular levels of inositol phosphates in cells were decreased within 5 minutes after UV treatment. The size of inositol-1,4,5-triphosphate pool in NIH3T3 cells was most sensitive to UV treatment. Competitive binding assay was carried out for the measurement of intracellular IP₃ contents based on the competition for the binding sites with lable and unIalled IP₃. Microsomal preparations from bovine adrenal cortex were used as binding protein. This study indicated that UV irradiation might indirectly affect DNA synthesis by impediment of inositol phosphate metabolism in the cells.

0.2% C강의 미세조직에 따른 3-body 연삭마멸 특성 연구

윤나래(N. R. Yoon),김종철(J. C. Kim),정영중(J. -Y. Jeong),권혁우(H. W. Gwon),김용석(Y. -S. Kim) 한국소성가공학회 2011 한국소성가공학회 학술대회 논문집 Vol.2011 No.5

Abrasive wear behavior of 0.2 wt. % C steel with different microstructures was studied. The steel was heat treated to obtain various microstructures under different conditions. Three-body abrasive wear tests were carried out using a ball-cratering abrasive wear tester at fixed load of 0.2 N. Sliding speed and wear distance adopted were 0.05 m/sec and 50 m, respectively. A bearing steel ball was utilized as a counterpart. SiC particles of size approximately 4 ㎛ were used as the abrasive medium. The slurry concentration and feed rate were 0.75 g/ml and 1.15 g/min, respectively. The wear crater was examined using SEM, FESEM, and a surface profilometer to investigate the wear mechanism of the steel. It was found that the abrasive wear resistance was proportional to initial hardness of the heat treated steel.

AZ31B 마그네슘 합금 판재성형 마찰거동 분석

권혁우(H. W. Kwon),윤나래(N. Yoon),김종철(J. C. Kim),정영중(Y.-J. Jeong),김용석(Y.-S. Kim) 한국소성가공학회 2011 한국소성가공학회 학술대회 논문집 Vol.2011 No.10

During sheet metal forming of Mg alloys, significant tribological problems such as wear, friction and galling occur. "Galling is the gross damage include scratching, grooving and plastic deformation of surfaces of metal sheet (or tools), which is associated with adhesive or stiction. When two surfcaces contact each other, a real contact will occur as asperities, and the contact forms as adhesive particle. The formation of the adhesive particle is one of major causes of the galling occuring at surfaces of the metal sheet and tools. In the present study, the galling characteristics between AZ31B Mg alloy sheets and tool steels (STD-11, STD-16) were evaluated. Reciprocative sliding test. Wear volume of the AZ31B alloy sheet and tool steels were calculated. Worn surfaces of the AZ31B sheet and tool steels were observed by SEM and EDS, and the topography of the survaces was obtained by a surface profilometer. Severe damage due to adhesive particles was observed on the AZ31B Mg alloy specimens. It is conformed that a material pick-up (adhesion) occurs almost instantaneously when asperities of the Mg alloy sheet and the too steels contact, which produces adhesive particles.

알루미늄판재 성형성 예측을 위한 평면이방성 해석기술 개발

김윤근(Y. G. Kim),정완진(W. J. Chung),김성태(S. T. Kim),문명수(M. S. Moon),윤정환(J. W. Yoon) 한국소성가공학회 2006 한국소성가공학회 학술대회 논문집 Vol.2006 No.5

Human Fas Ligand Expression on Pig Cells can Inhibit Xenogeneic Antibody-dependent Cell-mediated Cytotoxicity

K. W. Park,K. M. Choi,S. H. Kim,S. P. Hong,J. Y. Yoo,H. M. Choi,Y. C. Park,M. Y. Park,Y. J. Yoon,J. G. Seol 한국동물생명공학회(구 한국동물번식학회) 2008 발생공학 국제심포지엄 및 학술대회 Vol.2008 No.1