DCA-MOD 법에 의한 High $J_c$ YBCO 박막의 제조

김병주,김혜진,이금영,이종범,김호진,이희균,홍계원,Kim, Byeong-Joo,Kim, Hye-Jin,Yi, Keum-Young,Lee, Jong-Beum,Kim, Ho-Jin,Lee, Hee-Gyoun,Hong, Gye-Won 한국초전도학회 2006 Progress in superconductivity Vol.8 No.1

High $J_c\;YBa_2Cu_3O_x$ superconducting films were fabricated by MOD method using fluorine-free dichloroacetic acid(DCA) as chelating solvent for preparing precursor solution. Coating solutions were prepared by dissolving Y-, Ba- and Cu-acetates in DCA solvent followed by drying in rota vapor to obtain the blue gel that is diluted in methanol and 2-methoxyethanol for adjusting the cation concentration. DCA-MOD precursor solution was coated on a single crystal(001) $LaAlO_3(LAO)$ substrate by a dip coating method with a speed of 25 mm/min. Coated films were calcined at lower temperature up to $500^{\circ}C$ in flowing oxygen atmosphere with a 7.2% humidity. Conversion heat treatment was performed at various temperatures of $780{\sim}810^{\circ}C$ for 2 h in flowing Ar gas containing 1000 ppm oxygen with a humidity of 9.45%. SEM observations showed that films have very dense microstructures for the films prepared at the temperature higher than $800^{\circ}C$ regardless of diluting solvent; methanol or 2-methoxyethanol. X-ray diffraction analysis showed that YBCO grains grew with a (001) preferred orientation. A High critical current density($J_c$) of 1.28 $MA/cm^2$(@77 K and self-field) was obtained id. the YBCO film prepared using 2-methoxyethanol as a solvent.

대동맥 축착증 -2례 보고-

김병주,이홍균,Kim, Byeong-Ju,Lee, Hong-Gyun 대한흉부심장혈관외과학회 1984 Journal of Chest Surgery (J Chest Surg) Vol.17 No.3

Coarctation of the Aorta is a congenital constriction of aorta of varying degree, usually located at or near the aortic ismuth with frequent associations of other cardiac anomalies. Various modes of surgical corrections, such as resection and end-to-end anastomosis, graft interposition, angioplasty using prosthetic patch or subclavian flap have been used according to the status of coarctation and age of the patient. We have experienced two cases of surgically treated coarctation of the aorta, one of which was preductal coarctation with hypoplastic aortic arch and ventricular septal defect in a 4 year old boy, and the other case was juxtaductal type with aortic regurgitation. Subclavian flap angioplasty with additional pulmonary artery banding procedure was done in the first case and wedge resection with end-to-end anastomosis and aortic valve replacement [St. Jude valve, 23mm] 20 days later of first operation in the other case. The first case developed massive tarry stool on 3rd POD, probably due to mesenteric arteritis with resultant bowl ecrosis, and expired the next day. Recovery was uneventful with the second case.

이동 로봇을 위한 온라인 동시 지도작성 및 자가 위치 추적 알고리즘

김병주,Kim, Byung-Joo 한국데이터정보과학회 2011 한국데이터정보과학회지 Vol.22 No.6

본 연구에서는 실제 환경에 적용 가능한 지능형 자율 이동 방법을 개발하기 위해 위치정보를 사용하지 않고 지도 작성이 가능한 지능형 이동 알고리즘을 제안한다. 제안한 알고리즘은 온라인으로 동작하면서 위치 정보를 사용하지 않고 지도 작성이 가능 할 뿐 아니라 현실 세계에 적용 가능하기 위해 많은 계산량을 요구하지도 않는다. 이는 이동 로봇의 실세계 주행과 같은 대용량의 이미지 처리가 필요한 경우에는 매우 유용하게 사용될 수 있다. 토이 자료와 대용량 자료에 대해 제안한 알고리즘을 적용한 결과 기존의 방법에 비해 적은 메모리와 새로운 입력에 대해 고유공간을 새로 계산하지 않아도 되어 로봇의 현실세계의 주행에도 문제가 없는 것으로 판단되었다. In this paper we propose an intelligent navigation algorithm for real world problem which can build a map without localization. Proposed algorithm operates online and furthermore does not require many memories for applying real world problem. After applying proposed algorithm to toy and huge data set, it does not require to calculate a whole eigenspace and need less memory compared to existing algorithm. Thus we can obtain that proposed algorithm is suitable for real world mobile navigation algorithm.

보행 편의성 분석을 위한 3차원 실내지도 기반의 시뮬레이션 기술 개발

김병주,강병주,유소영,권재현,KIM, Byung-Ju,KANG, Byoung-Ju,YOU, So-Young,KWON, Jay-Hyoun 한국지리정보학회 2017 한국지리정보학회지 Vol.20 No.3

정시성이 보장된 도시철도에 대한 수송 의존도가 높아짐에 따라 수송 능력 뿐만 아니라 이용객의 편의성이 중요시 되고 있다. 이에 본 연구에서는 도시철도역사의 개선 및 신규 역사 건설 시 이동속도, 환승거리와 같은 보행 환경을 사전에 정량적으로 평가하기 위한 시뮬레이터를 개발하였다. 시뮬레이터는 3차원 실내지도 저작 모듈과 보행 알고리즘을 수행하는 모듈로 구성되어 있다. 3차원 실내지도 저작 모듈에서는 3차원 공간 모델링, 네트워크 생성 및 평가 결과 표출 등의 기능을 수행하며, 보행 알고리즘에서는 경로탐색, 통행량 배정, 종합서비스 수준 평가 등의 기능이 있다. 이러한 기능의 핵심적인 부분은 공간정보 DB와 동적 통행정보 DB를 유기적으로 연결하여, 전후 상황 등 다양한 시나리오의 적용과 분석을 반복적으로 수행할 수 있다는 점이다. 또한, 향후 시뮬레이터의 활용 방안 제시를 위해 실제 운영 중인 역사를 대상으로 Test-Bed를 구축하고, 역사통행로의 개선 전 후의 보행 속도를 분석하여 개선 효과에 대한 정량적 지표를 산출하였으며, 향후 추가적인 분석을 위한 DB의 확장 가능성에 대해 논의하였다. Increasing transportation dependence on the metro system has lead to the convenience of passengers becoming as important as the transportation capacity. In this study, a pedestrian simulator has been developed that can quantitatively assess the pedestrian environment in terms of attributes such as speed and distance. The simulator consists of modules designed for 3D indoor map authoring and algorithmic pedestrian modeling. Module functions for 3D indoor map authoring include 3D spatial modeling, network generation, and evaluation of obtained results. The pedestrian modeling algorithm executes functions such as conducting a path search, allocation of users, and evaluation of level of service (LOS). The primary objective behind developing the said functions is to apply and analyze various scenarios repeatedly, such as before and after the improvement of the pedestrian environment, and to integrate the spatial information database with the dynamic information database. Furthermore, to demonstrate the practical applicability of the proposed simulator in the future, a test-bed was constructed for a currently operational metro station and the quantitative index of the proposed improvement effect was calculated by analyzing the walking speed of pedestrians before and after the improvement of the passage. The possibility of database extension for further analysis has also been discussed in this study.

비등유로의 압력강하 불안정성에 대한 실험적 고찰

김병주,신광섭,Kim, B.J.,Shin, K.S. 대한설비공학회 1993 설비공학 논문집 Vol.5 No.3

The characteristics of pressure-drop oscillations(PDO) in boiling channel are studied experimentally. The effects of initial and boundary conditions on PDO are investigated in terms of oscillation period and amplitude. The period and amplitude of PDO are increased with the increase in the compressible volume in surge tank and heat input. However the amplitude of PDO is decreased with fluid temperature under low subcooling condition. Higher initial insurge flowrate resulted in almost invariant oscillation period but lower amplitude. At higher heat input the oscillation of heater wall temperature is significant, whose period is the same as that of pressure-drop instability.

비등유로의 압력강하 요동특성

김병주,신광섭,Kim, B.J.,Shin, K.S. 대한설비공학회 1995 설비공학 논문집 Vol.7 No.1

Characteristics of pressure-drop oscillations(PDO) in a boiling channel were studied numerically and compared with experimental data. Effects of initial and boundary conditions on PDO were investigated in terms of oscillation period and amplitude. The period and amplitude of PDO increased with increasing of the compressible volume in the surge tank and the heat input. PDO occurred within the specific range of the fluid temperature, at which oscillation period and amplitude diminished rapidly with the increase of the fluid temperature. The increase of the loss coefficient in fluid supply line resulted in slightly longer oscillation period and larger amplitude. Numerical results showed good agreement with the experimental data.

리튬브로마이드 수용액 유하액막의 흡수과정에 대한 근사 해법 : 증기 유동의 영향

김병주,이찬우,Kim, B.J.,Lee, C.W. 대한설비공학회 1997 설비공학 논문집 Vol.9 No.2

Film absorption involves simultaneous heat and mass transfer in the vapor-liquid system. In the present work, the absorption process of water vapor by an aqueous soluton of LiBr flowing inside of the vertical tube was investigated. The continuity, momentum, energy and diffusion equations for the solution film and vapor were formulated in integral forms and solved numerically. The model could predict the film thickness, the pressure gradient, and the heat and mass transfer rate. Particularly the effects of vapor flow conditions on the absorption process were investigated in terms of the vapor Reynolds number. As the vapor Reynolds number increased, the shear stress at the vapor-solution interface also increased. Consequently solution film became thinner at higher vapor flowrate under the co-currentflow condition. Thinner film was capable of higher heat transfer to the wall and leaded to higher absorption rate of the water vapor into the solution film.

질산염 전구체 원료로 Ex-situ 공정에 의한 GdBCO 박막 제조

김병주,이철선,이종범,이재훈,문승현,이희균,홍계원,Kim, Byeong-Joo,Lee, Chul-Sun,Lee, Jong-Beom,Lee, Jae-Hun,Moon, Seung-Hyun,Lee, Hee-Gyoun,Hong, Gye-Won 한국초전도학회 2011 Progress in superconductivity Vol.13 No.2

Many research groups have been manufacturing coated conductor by various processes such as PLD, MOD, and MOCVD, but the methods with production cost suitable for wide and massive application of coated conductor did not develop yet. Spray pyrolysis method adopting ultrasonic atomization was tried as one of the possible option. GdBCO precursor films have been deposited on IBAD substrate by spray pyrolysis method at low temperature and converted to GdBCO by post heat treatment. Ultrasonic atomization was used to generate fine droplets from precursor solution of Gd, Ba, and Cu nitrate dissolved in water. Primary GdBCO films were deposited at $500^{\circ}C$ and oxygen partial pressure of 1 torr. After that, the films were converted at various temperatures and low oxygen partial pressures. C-Axis oriented films were obtained IBAD substrates at conversion temperature of around $870^{\circ}C$ and oxygen partial pressures of 500 mtorr ~ 1 torr in a vacuum. Thick c-axis epitaxial film with the thickness of 0.4 ~ 0.5 ${\mu}m$ was obtained on IBAD substrate. C-axis epitaxial GdBCO films were successfully prepared by ex-situ methods using nitrate precursors on IBAD metal substrate. Converted GdBCO films have very dense microstructures with good grain connectivity. EDS composition analysis of the film showed a number of Cu-rich phase in surface. The precursor solution having high copper concent with the composition of Gd : Ba : Cu = 1 : 2 : 4 showed the better grain connectivity and electrical conductivity.

DCA-MOD 법으로 YBCO 박막 제조시 하소열처리의 승온속도 효과

김병주,김혜진,조한우,권연경,유정희,이희균,홍계원,Kim, Byeong-Joo,Kim, Hye-Jin,Cho, Han-Woo,Kwon, Youn-Kyung,Ryu, Jung-Hee,Lee, Hee-Gyoun,Hong, Gye-Won 한국초전도학회 2007 Progress in superconductivity Vol.8 No.2

High $J_c\;YBa_2Cu_3O_{7-x}$ superconducting films have been fabricated $LaAlO_3(100)$ substrate by MOD method using dichloroacetic acid(DCA) as chelating solvent for preparing precursor solution. Heating rate was varied in order to optimize the calcination heat treatment condition in DCA-MOD method. Coated films were calcined at lower temperature up to $500^{\circ}C$ in flowing humid oxygen atmosphere. The heating rate was calcined from $13.3^{\circ}C/min\;to\;0.28^{\circ}C/min$. Conversion heat treatment was performed $800^{\circ}C$ for 2 h in flowing Ar gas containing 1000 ppm oxygen with a humidity of 9.45%. Surface and cross sectional SEM microstructures showed that particle sizes were increased with heating rate at a calcination step. The amount of pores was increased with heating rate in the calcined films. Dense microstructure and sharp texture were developed in an YBCO films after conversion heat treatment. A high critical current density (Jc) of $1.26MA/cm^2$ (@77 K and self-field) was obtained for the YBCO film which was prepared with a heating rate of $0.28^{\circ}C/min$.

만성 B형 간염 바이러스 감염 환자에서 혈청 Cytokine에 관한 연구

김병주,마재숙,황태주,Kim, Byung-Ju,Ma, Jae-Sook,Hwang, Tai-Ju 대한소아소화기영양학회 1998 Pediatric gastroenterology, hepatology & nutrition Vol.1 No.1

목 적: 혈청 B형 간염 바이러스 표면 항원(HBsAg)이 양성인 만성 보유자 35명에서 혈청 Th1계 싸이토카인(IL-2, TNF-${\alpha}$ 및 IFN-${\gamma}$)과 Th2계 싸이토카인(IL-4와 IL-10)을 측정하여 만성 B형 간염 바이러스 감염 환자의 병태에 따른 싸이토카인의 변화를 구명하고자 하였다. 방 법: 대조군은 항 HBs 항체 양성인 정상 소아 7명이었고 환자군 35례중 HBeAg 양성군은 20례, 항 HBe 항체 양성군은 15례이었으며 간 조직검사를 시행한 19례중 만성 지속성 간염은 10례, 만성활동성 간염은 9례이었다. 말초 정맥혈로부터 혈청을 분리하여 aminotransferase, B형 간염 바이러스 표지자 검사 및 ELISA로 싸이토카인(IL-2, TNF-${\alpha}$, IFN-${\gamma}$, IL-4 및 IL-10)을 측정하였다. 결 과: 1) HBe 항원 양성인 환자에서 항 HBe 항체 양성인 환자에 비해 그리고 만성 활동성 간염 환자에서 지속성 간염 환자에 비해 의의 있게 혈청 AST와 ALT치가 높았다. 2) HBe 항원 양성인 환자에서 항 HBe 항체 양성인 환자에 비해 IL-10이 의의 있게 높았다. 3) 만성 활동성 간염 환자에서 지속성 환자에 비해 통계학적인 의의는 없었으나 측정한 모든 싸이토카인이 높은 경향을 보였다. 4) 혈청 아미노전이 효소치가 100 U/L 이상인 환자에서 IL-2, TNF-${\alpha}$, IFN-${\gamma}$ 및 IL-10이 높은 경향을 보였고 혈청 아미노전이 효소치가 정상인 환자에서 효소치가 높은 환자에 비해 IL-4가 높은 경향을 보였다. 결 론: Th2계 싸이토카인인 IL-10의 증가는 간염의 활성도보다는 HBe 항원의 지속성과 관련이 있고 Th1계의 싸이토카인인 IL-2, TNF-${\alpha}$ 및 IFN-${\gamma}$는 간염의 활성도 증가와 관련이 있음을 시사하였다. Purpose: The aim of this study was to clarify the serum cytokine pattern in patients with chronic HBV infection in terms of their clinical state. Methods: Intravenous blood samples were taken from 35 patients who were seropositive for HBsAg for at least 6 months and 7 healthy controls. Samples were initially tested for serum aminotransferases and serologic markers for hepatitis B virus by EIA. Serum levels of interleukin(IL)-2, tumor necrosis factor-alpha (TNF-${\alpha}$), interferon-gamma (IFN-${\gamma}$), IL-4, and IL-10 were measured by ELISA. Results: Among 35 patients, seropositive for HBeAg was 20 and for anti-HBe was 15. The histologic diagnosis of 19 patients underwent liver biopsy were chronic persistent hepatitis (CPH) in 10 and chronic active hepatitis (CAH) in 9. Serum IL-10 level in patients seropositive for HBeAg was significantly higher than that in patients seropositive for anti-HBe (p<0.05). All measured cytokine levels in patients with CAH were higher than those of patients with CPH. High values of all measured cytokines except IL-4 were seen in patients with AST and ALT > 100 U/L. High level of IL-4 was seen in patients with normal aminotransferase levels. Conclusion: These results were thought to indicate that anti-inflammatory Th2-like cytokine (IL-10) production in chronic HBV infection is related to circulating HBeAg rather than activity of hepatitis and that Th1 cytokines seem to be associated with the increasing activity of hepatitis.