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.

DCA-MOD 방법으로 제조된 YBCO 박막의 미세조직에 미치는 열처리 효과

김병주,김혜진,조한우,유석구,유정희,이희균,홍계원,Kim, Byeong-Joo,Kim, Hye-Jin,Cho, Han-Woo,Yu, Seok-Koo,Ryu, Jung-Hee,Lee, Hee-Gyoun,Hong, Gye-Won 한국초전도학회 2007 Progress in superconductivity Vol.9 No.1

[ $YBa_2Cu_3O_{7-{\delta}}$ ] films have been prepared on $LaAlO_3$ (100) single-crystal substrates by a metalorganic deposition using dichloroacetate precursors (DCA-MOD). Calcination conditions were varied in order to optimize the microstructure and the superconducting properties of YBCO film. Coated films were calcined at various temperatures ranging from $400{\sim}700^{\circ}C$ in flowing humid oxygen atmosphere. Ramping rate to calcination tempertures was $2.22^{\circ}C/min$. Conversion heat treatment was performed at $800^{\circ}C$ for 2 h in flowing Ar gas containing 1000 ppm oxygen with a humidity of 9.45%. Observations of surface and cross sectional SEM microstructure showed that the particle size in the calcined film increased in the range of 100-200 nm with heating rate and the calcination temperature. SEM EDS analysis showed that 13 a/o of chlorine was contained in the calcined film. It was also observed that the porosity increased with the heating rate and temperature. Porous microstructure was developed when YBCO films were prepared using porous calcined film. Dense microstructure and high $J_c$ over $1\;MA/cm^2$ was obtained when calcination was carried out at the temperature of $500^{\circ}C$ with a heating rate of $2.22^{\circ}C/min$.

부산시립박물관 소장 철판 갑옷의 보존복원처리

김병주,Kim, Byeong-Ju 국립문화재연구소 1988 保存科學硏究 Vol.9 No.-

질산염 전구체 원료로 분무 열분해 방법에 의한 YBCO 박막 증착

김병주,홍석관,김재근,이종범,이희균,홍계원,Kim, Byeong-Joo,Hong, Seok-Kwan,Kim, Jae-Geun,Lee, Jong-Beom,Lee, Hee-Gyoun,Hong, Gye-Won 한국초전도학회 2010 Progress in superconductivity Vol.12 No.1

Y123 films have been deposited on $LaAlO_3$ (100) single-crystal and IBAD substrates by spray pyrolysis method using nitrate precursors. Ultrasonic atomization was adopted to decrease the droplet size, spraying angle and its moving velocity toward substrate for introducing the preheating tube furnace in appropriate location. A small preheating tube furnace was installed between spraying nozzle and substrate for fast drying and enhanced decomposition of precursors. C-axis oriented films were obtained on both LAO and IBAD substrates at deposition temperature of around $710{\sim}750^{\circ}C$ and working pressures of 10~15 torr. Thick c-axis epitaxial film with the thickness of $0.3{\sim}0.6\;{\mu}m$ was obtained on LAO single-crystal by 10 min deposition. But the XRD results of the film deposited on IBAD template at same deposition condition showed that the buffer layers of the IBAD metal substrate was affected by long residence of metal substrate at high temperature for YBCO deposition.

실시간 침입탐지 시스템에 관한 연구

김병주,Kim, Byoung-Joo 한국정보통신학회 2005 한국정보통신학회논문지 Vol.9 No.1

인공지능, 기계학습 및 데이터마이닝 기법들을 침입탐지 시스템에 적용하는 연구가 활발히 진행되고 있다. 그러나 많은 연구가 공격패턴의 분류를 위한 분류기(classifier)의 학습 알고리즘 성능 개선에 목적을 두고 있다. 그리고 이러한 학습 알고리즘은 대부분 일괄처리(batch) 방식으로 동작하여 실시간 침입탐지 시스템의 적용에는 적합하지 못하다. 본 논문에서는 실시간 침입탐지 시스템을 위한 점증적 특징 추출 기법과 분류가 가능한 실시간 침입탐지 시스템을 제안한다. 제안된 방법을 KDD CUP 99 자료에 적용한 결과 실시간 기법임에도 불구하고 일괄처리 방식과 비슷한 결과를 나타내었다. Applying artificial intelligence, machine learning and data mining techniques to intrusion detection system are increasing. But most of researches are focused on improving the performance of classifier. These classifiers are performed by batch way and it is not proper method for realtime intrusion detection system. We propose an incremental feature extraction and classification technique for realtime intrusion detection system. Applying proposed system to KDD CUP 99 data, experimental result shows that it has similar capability compared to batch way intrusion detection system.

사서교사의 역할에 대한 인식연구

김병주,Kim Byong Ju 한국문헌정보학회 1989 한국문헌정보학회지 Vol.17 No.-

The school library plays very important and central role for the fullfillment of educational objective in the process of implementing the school curriculum. And the media specialist known as teacher-librarian is. primarily responsible for the successful operation and effective management of the media center. It is true that effectiveness of the school library depends greatly on the cooperative coordination among teacher-librarian, teacher and principal in addition to the strong support and effective supervision of school district authority, specifically, supervisor of school library program. The successful program therefore is influenced by their perception of the teacher-librarian's role. The purpose of this study was to investigate the teacher-librarian's. educational role perceived by teacher-librarian, teacher, principal and school district supervisor. A standard task model describing both the management and educational functions and expectations of teacher-librarian was proposed after studying the relevant current standards of four countries. Serveral hypotheses were made regarding role perception and a survey instrument was designed based on this proposed task model and the results of the literature review to validate the hypotheses. The questionnaires were mailed out and the returned questionaires were analyzed by SPSS computer routine. The major findings are summarized as follows: 1) There was difference of the role perception among teacher-librarian, teacher, principal and district supervisor at the significance level of p<0.001 for both management and educational functions of teacher­librarian. The mean score of the teacher-librarian was highest among four groups and the score for the educational function tasks were lower than that of management function tasks. 2) The positive correlation exists at the significance level of p<0.001 between the role perception and the attitude toward changing social trends such as acceptance of new technology, need for better communication and information. 3) The positive correlation exists at the significance level of p<0.001 between the role perception and the view on the curriculum and teaching method.

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.

복셀 맵을 이용한 단백질 표면 원자의 발견 알고리즘

김병주,김구진,성준경,Kim, Byung-Joo,Kim, Ku-Jin,Seong, Joon-Kyung 한국정보처리학회 2012 정보처리학회논문지 A Vol.19 No.2

본 논문에서는 단백질 분자로부터 표면 원자를 효율적으로 발견하는 알고리즘을 제안한다. 표면 원자란, 주어진 probe solvent $P$가 단백질 분자와 충돌하지 않고 접한다고 가정할 때, $P$와 접할 수 있는 원자의 집합을 의미한다. 단백질 분자를 구성하는 원자들은 반데르바스 반경을 갖는 구의 집합으로 표현되며, probe solvent 역시 구로 대응된다. $P$의 반경에 대해 분자의 오프셋 곡면을 구하여 표면 원자를 발견하는 알고리즘을 제안한다. 제안된 알고리즘은 각 구의 오프셋 곡면에 대해 복셀 맵(voxel map)을 구성하여 효율적으로 분자의 오프셋 곡면을 구하며, GPU (graphic processor unit)를 활용한 병렬처리를 수행하여 최대 6,412개의 원자를 갖는 분자에 대해 42.87 millisecond 내에 표면 원자를 발견한다. In this paper, we propose an efficient method to extract surface atoms from a protein molecule. Surface atoms are defined as a set of atoms who can contact given probe solvent $P$, where $P$ does not collide with the molecule. The atoms contained in the molecule are represented as a set of spheres with van der Waals radii. The probe solvent also is represented as a sphere. We propose a method to extract the surface atoms by computing the offset surface of the molecule with respect to the radius of $P$. For efficient computation of the offset surface of a molecule, a voxel map is constructed for the offset surfaces of the spheres. Based on GPU (graphic processor unit) acceleration, a data parallel algorithm is used to extract the surface atoms in 42.87 milliseconds for the molecule containing up to 6,412 atoms.

대학의 납입금 책정을 위한 몇 가지 제언

김병주,Kim, Byeong-Ju 한국대학교육협의회 1994 大學敎育 Vol.72 No.-

여타의 재원이 매우 경직되어 있는 우리 대학의 재정구조에서 납입금 책정 문제는 대단히 중요하다. 이 문제는 단순히 대학 교육비 총액과 추가소요교육비를 추정하여 이 중에서 납입금 부담분만을 산출해 내는 것만으로 끝나지 않는다. 여기에는 대학재정 전반은 물론 대학교육 및 그를 둘러싸고 있는 사회 전반이 관련되어 있다. 대학납입금의 적정 인상률은 물가 상승률이나 인건지 인상률, 각종 교육여건의 개선계획, 다른 재원의 확보가능성은 물론, 여론이나 학생들의 반발, 정부의 물가정책, 학부모 부담능력 등을 고려하여 결정된다. 개별대학들은 이러한 점을 충분히 인식하고 자체적인 교육비 분석, 대학재정 운영의 투명성 확보, 인근대학과의 협력, 대학납입금 예고제의 활용 등을 통하여 합리적이고 적정한 납입금을 책정할 수 있다.

대학재정 확충방안

김병주,Kim, Byeong-Ju 한국대학교육협의회 2007 大學敎育 Vol.150 No.-

부존자원이 부족한 우리나라에서 그간 발전의 원동력이 되어온 것은 바로 "교육"이다. 최근 우리나라의 고등교육재정 부족에 대한 우려의 목소리가 높다. 대학의 경쟁력이 곧 국가의 경쟁력으로 이어지는 현대 사회에서 각 대학의 경쟁력 강화를 위해 재정 투자의 확대와 재정 투자의 효율성에 대한 요구가 각계각층에서 이어지고 있다. 이에 우리나라 고등교육재정 현황 및 재정 부족에 대한 원인과 문제점을 짚어보고, 이를 확충하기 위한 방안에는 어떠한 것들이 있는지 살펴보기로 한다.