EFFECT OF AGE ON THE LEVEL OF SERUM ALKALINE PHOSPHATASE ACTIVITY OF JAPANESE BLACK STEERS

Sekine, J.,Udagawa, K.,Morita, Z.,Oura, R. Asian Australasian Association of Animal Productio 1989 Animal Bioscience Vol.2 No.2

The level of serum alkaline phosphatase activity was determined in 7 Japanese Black steers at different ages. The isoenzyme activity of non-bone origin was estimated using a heat-inactivation technique. The activity of serum alkaline phosphatase (SALP, K-A unit) decreased as age (AGE, mo.) increased: SALP = 14.15 - 0.17 (${\pm}\;0.03$) AGE, r = -0.81, P<0.01, $S.E.\;{\pm}\;0.28$. The variation of the activity was greater in younger age than the older. The temperature of $58^{\circ}C$ for the treatment of heat inactivation of bovine serum appeared to be suitable. The percentage of heat inactivated enzyme activity negatively correlated with age and positively with the level of serum alkaline phosphatase activity. The activity of SALP of non-bone origin was inferred to stay at about constant level irrespective of age and that of bone origin decreased with age.

극소전계전자방출 전류밀도 검출을 위한 센싱 시스템 개발

류정탁,K., Oura,김연보 대구대학교 정보통신연구소 2003 情報通信硏究 Vol.1 No.2

본 연구에서 개발된 전계전자방출 측정 시스템은 FE(field emission) 디바이스 전체에 대한 전기적 특성을 평가할 수 있을 뿐만 아니라 극미소한 영역에 대한 전계적 특성도 측정할 수 있다. 따라서 FE 디바이스의 물리적 및 전기적 특성을 보다 정밀하게 마이크로 단위로 평가할 수 있어 우수한 FE 디바이스의 개발 및 개선에 큰 도움을 줄 수 있다. 또한 이 극소전계전자방출 측정 시스템은 FE 디바이스가 전계에 의해 방출하는 전류밀도를 2차원적 및 3차원적으로 표시가 가능하므로 FE 디바이스의 특성을 직관적으로 평가할 수 있다. In this research, we developed the electric field electron emission measurement system of new form. This system can measure electric field characteristic about a microscopic area as well as all over area of a field emission (FE) device. Therefore, this system can give big help in development and improvement of more superior FE device because of measurement capacity for physical and electric property of FE device about a microscopic area. Also, we can intuitionally evaluate FE device characterization, because this system displays possible two-dimensional and three-dimensional current density emitted from FE device by electric field.

RF 마그네트론 스퍼터링법으로 성장된 Amorphous carbon 각막의 전계전자방출

김연보,류정탁,K. Oura 한국전기전자재료학회 2001 전기전자재료학회논문지 Vol.14 No.3

Using RF magnetron sputtering, amorphous carbon(a-C) thin films as electron filed emitter were fabricated. these a-C thin films were deposited on Si(001) substrate at several temperatures. The field electron emission property of these a-C thin films was estimated by a diode technique. As the result, we observed that the field emission properties of the films were changed singnificantly with the substrate temperature and structural features of a-C film. The field emission properties were promoted by higher substrate temperatures. Furthermore N-doped a-C film exhibits more field emission property than that of undoped a-C film. These results are explained as change of surface morphology and structural properties of a-C film.

질소 플라즈마처리에 의한 a-C 박막의 전계방출특성 변화에 관한 연구

Ryu, Jeong-Tak,Lee, K.Y.,Honda, S.,Katayama M.,Oura, K. 한국전기전자재료학회 2004 전기전자재료학회논문지 Vol.17 No.12

Amorphous carbon (a-C) films have been deposited on Si(100) substrate using RF magnetron system in order to investigate the electron field emission properties. The a-C films were treated by $N_2$ gas plasma at room temperature. Surface morphologices and structural properties of the a-C films before and after $N_2$ plasma treatment were observed by scanning electron microscopy and Raman spectroscope, respectively. Structural properties and surface morphology of the a-C films were changed by $N_2$ plasma treatment. The emission properties can be improved by the plasma treatment according to the contents of nitrogen on the a-C films which is varied by plasma treatment time. Before the plasma treatment, the a-C films are found to have a threshold field of 14 V/$\mu$m, but the a-C film treated by $N_2$ plasma for 30 min exhibit threshold field as low as 6.5 V/$\mu$m.

(A) Study on low temperature growth of carbon nanofibers for field emission display /

Ikuno, T.,김연보,Oura, K.,류정탁,Katayama, M. 大邱大學校 情報通信硏究所, 2002 情報通信硏究 Vol.1 No.1

PECVD에 의해 작성된 탄소계 박막의 전계전자방출특성에 대한 증착온도 의존성에 관한 연구

류정탁,백양규,이형주,M. Katayama,K. Oura 한국진공학회 2003 Applied Science and Convergence Technology Vol.12 No.1

본 논문에서는 혼합가스 없이 메탄가스만을 사용하여 RF PECVD 방법으로 성장시킨 a-C 박막의 전계전자방출특성을 조사하였다. 또한 본 논문은 박막의 표면형태와 결정들의 결합구조가 어떻게 전계전자방출에 영향을 미치는가에 관하여 보고된다, a-C 박막의 전계전자방출특성은 증착온도에 크게 의존함이 확인되었다. 실온에서 성장된 카본박막의 문턱전압은 20 V/$\mu\textrm{m}$이었다. 그러나 증착온도가 $500^{\circ}C$로부터 $600^{\circ}C$로 증가함에 따라 문턱전압은 17 V/$\mu\textrm{m}$에서 10 V/$\mu\textrm{m}$으로 감소하였으며 $800^{\circ}C$에서는 문턱전압이 B V/$\mu\textrm{m}$로 크게 개선되었다. 박막의 표면형태, 구조적인 특징과 전계전자방출특성의 관계를 조사하기 위해서 라만 스펙트럼과 주사형전자현미경 (scanning electron microscopy : SEM)을 사용하였다. 박막의 물리적, 화학적, 특성은 증착온도에 매우 의존하며 이들 특성들은 전계전자방출특성에 큰 영향을 미친다는 사실을 발견했다. Using RF plasma enhanced chemical vapor deposition, amorphous carbon films were grown in pure methane plasma. Field electron emission of these films were examined at a function of deposition temperature. It was found that the electron emission current of the sample prepared at deposition temperature above $600^{\circ}C$ was considerably improved. The film grown at deposition temperature of $800^{\circ}C$ had the best threshold field of 8 V/$\mu\textrm{m}$ in this experiment. According to the results of Raman spectroscopy. growth of graphite crystallites was promoted with higher deposition temperatures. Moreover the surface morphology was abruptly changed at deposition temperature above $600^{\circ}C$. We discuss the field electron emission characteristics of amorphous carbon films with regard to the structural feature and surface morphology.

RF-PECVD를 이용한 순수메탄 플라즈마에서 성장된 탄소계 박막의 제작 및 특성

조경제,류정탁,백양규,T.IKUNO,S.HONDA,K.OURA,이상윤 한국물리학회 2002 새물리 Vol.44 No.2

Amorphous carbon films were fabricated in a pure methane plasma by using radio frequency plasma-enhanced chemical vapor deposition. The surface morphology and the roughness of the films were examined as functions of the substrate temperature by using atomic force microscopy (AFM). We found that the roughness of the films improved considerably for substrate temperatures higher than 500 $^\circ$C. From the AFM and Raman spectroscopy results, growth of graphite crystallites was promoted by high substrate temperatures. Furthermore, the surface morphology abruptly changed at substrate temperatures over 600 $^\circ$C. These results can be explained as the characteristics of amorphous carbon films with regard to the surface morphology and the structural features. 비정질 탄소 박막을 RF-PECVD(Radio Frequency Plasma Enhanced Chemical Vapor Deposition) 를 이용한 순수 메탄 플라즈마에서 제작하였다. 기판 온도의 변화에 따른 박막에 대한 표면 형태와 거칠기는 AFM(Atomic Force Microscopy)에 의해서 조사하였다. 본 연구에서 박막의 표면 형태는 기판 온도 600 $^\circ$C 에서 급격하게 변화되었으며 AFM에 의한 표면 거칠기의 정도도 큰 변화가 보였다. AFM 과 Raman spectroscopy 결과로부터 기판 온도가 높을수록 박막은 그라파이트화 되어 갔다. 이러한 결과로부터 비정질 탄소 박막의 표면형태와 구조적 특성에 관하여 설명하였다.

나노입자가 내장된 기능성 박막의 제작과 전자소자 특성

류정탁(Jeong Tak Ryu),T. Ikuno,S. Honda,M. Katayama,K. Oura 한국산업정보학회 2006 한국산업정보학회논문지 Vol.11 No.4

나노입자가 내장된 기능성 박막의 제작과 전자소자 특성

Ryu, Jeong-Tak,Ikuno, T,Honda, S.,Katayama, M.,Oura, K. 한국산업정보학회 2006 한국산업정보학회논문지 Vol.11 No.4

본 논문에서는 DC 플라즈마와 금속유기물을 사용하여 CNF의 저온 합성에 성공하였다. 합성된 CNTs는 기판의 위치에 따라 매우 다른 특성 차이가 보였다. CNT는 일반적으로 직경 100 nm, 길이 $10{\mu}m$의 특성을 가진다. CNT의 형태적 특성들은 전계전자방출특성에 큰 영향을 준다는 사실을 본 연구를 통해 알 수 있었다. 따라서 CNF의 합성에 의한 CNF 구조적 특성은 전자소자응용면에서 매우 중요한 역할을 한다. Carbon nanofibers have synthesized a low temperature using DC Ar plasma and Fe-Phthalocyanine, and a characteristic difference of the synthesized CNF according to the location of the substrate was investigated. The carbon nanofibers had about 100nm diameter and up to $10{\mu}m$ length. These were grown in random orientation. There are two shapes in the CNFs, screw and straight line shapes. Furthermore, we found the selective growth of nanofibers on the scratched substrates. The density of CNFs synthesized on the position (a) were higher than that synthesized on the position (b) [See the Fig. 2]. Also, the length of CNFs was different. In the shape, CNFs with screw and straight line shape were synthesized in the position (a), but. only CNFs with straight line shape were synthesized in the position (b). The difference have an important effect on the field emission characteristics.