고온 초전도체 Y₁Ba₂Cu₃O에서 Y의 Sm 치환 효과

김채옥,김필수,김의훈,김재욱 漢陽大學校 基礎科學硏究所 1992 基礎科學論文集 Vol.11 No.-

고온 초전도체 Y₁Ba₂Cu₃O??에서 Y를 Sm으로 치환시켰을 때의 수송 임계 전류밀도와 저항의 측정은 각각 77K와 80-160K범위의 온도에서 조사되었다. 그리고 X-선 회절 분석 및 적외선 투과율 측정은 실온에서 수행되었으며, 시료들은 고상 반응법에 의해서 제조되었다. 한편 치환양이 증가함에 따라서 정상상태에서의 저항값은 증가하는 경향을 보였고, 93K 근처에서 초전도 전이온도 Tc를 갖고 있으며, 치환양에 따라 거의 변화지 않았다. 적외선 투과율 측정결과 날카로운 peak들은 472.78~618.53㎝-1범위에 있었다. 이것은 특이할 정도로의 low-lying plasmalike edge와 낮은 에너지의 전자적인 여기가 존재함을 나타내는 것이다. 수송임계 전류밀도는 43.3~123.9A/㎠ 범위에 있었다. 전이온도 Tc에 상자성 불순물의 영향이 거의 없는 것으로 보아 123phase에서 Y가 고온 초전도성에 주된 역할을 하지 않음을 알 수 있었다. The measurements of the transport critical current density and resistivity of high Tc superconductor Y₁Ba₂Cu₃O?? were made at 77K and in the range of 80~160K. X-ray pellet diffraction and IR transmittance measurements were carried out at room tempemature. The samples in which Y is replaced by Sm were prepared by solid state reaction. As substitution content increased, the normal state resistivity was increased and the superconducting transition temperature Tc near 93K did not change significantly with the substitution content. From the infrared transmittance measurements many sharp peaks were observed in the range of 472.78~618.53㎝?. It indicates that unusual low-lying plasmalike edge and low energy electronic excitation exist. The values of transport critical current densities were in the range of 43.3~123.9A/㎠. From the observation of no significant change in Tc with mangetic rare earth impurities, it could be concluded that Y plays no crucial role in the high Tc superconduction mechanisms at the 123 phase.

유도 허벅다리걸기 기술발휘 시 받기의 자세와 저항수준에 따른 중심변인 분석 사례연구(Ⅱ)

김의환,김성섭,정재욱 한국운동역학회 2005 한국운동역학회지 Vol.15 No.1

E. H. KIM, S. S. KIM, C. W. CHUNG. A Case Study on Center of Gravity Analysis when Performing ilchimata by Posture and Voluntary Resistance Levels of Uke in Judo[ II]. Korean Journal of Sport Biomechanics, Vol. 15, No. 1, pp. 237.-257, 2005. It was to study as a following-research of "A Case Study on Center of Gravity(COG) Analysis when Performing Uchimata(inner thigh reaping throw) by Posture and Voluntary Resistance Levels(VRL) of Like in Judo[1]". The purpose of this study was to analyze the COG variables when performing uchimata(inner thigh reaping throw) by two postures and voluntary resistance Jevels(VRL) of uke(reciver) in Judo. The subjects, who were one male judoka(YH) for 1992 Barcelona Olympic Games Olympian(silver medalist), and one male trainee; Y.I.University representative member (SDK), and were filmed on two S-VHS 16mm video cameras(60fields/sec.) through 3-dimensional motion analysis methods, that postures of uke were shizenhontai (straight natural posture) and jigohontai(straight defensive posture), VRL of uke were 0% and 100%, respectively. The kinematical variable was COG variable, distance of COG, and distance of resultant COG between uke and tori(the thrower), velocity and acceleration of COG. The data of this study collection were digitized by SIMI Motion Program computed the mean values and the standard deviation calculated for each variables. When performing uchinwta according to each posture and VRL of uke and classifying. From the data analysis and discussion, the conclusions were as follows : 1. Displacement of COG Subject YH, COG was the highest in kuzushi(balance -breaking), vertical COG was low when following in tsukuri(positioning; set-up), kake(application; execution), and COG was pattern of same character each postures and resistance, respectively. Subject SDK, COG was low from kumikata(engagement positioning) to kake, and COG was that each postures and resistance were same patterns, respectively. Subject YH, SDK, each individual, postures and resistance, vertical COG was the lowest in kake phase, when performing. 2. Distance of COG between uke and tori The distance of COG between uke and tori when performing, subject YH was 0.64-0.70cm in kumikata, 0.19-0.28cm in kake, and SDK was 0.68-0.72cm in kumikata, 0.30-0.42 cm in kake. SDK was wider than YH. 3. Distance of resultant COG between uke and tori The distance of resultant COG between uke and tori when performing, subject YH was 0.27-0.73cm from kumikata to kake. and SDK was 0.14-0.34cm in kumikata, 0.28- 0.65cm in kake. Jigohontai(YH:0.43-0.73cm,SDK:0.59-0.65cm) was more moved than shizenhontai(YH:0.27-0.53cm, SDK: 0.28- 0.34cm). 4. Velocity of COG The velocity of COG when performing uchimata, subject YH was fast anterior-posterior direction in kuzushi, ant-post. and vertical direction fast in tsukuri and kake. SDK was lateral, ant.-post. and vertical direction in kuzushi, ant.-post. and vertical direction in tsukuri and ant.-post. direction in kake, respectively. 5. Acceleration of COG The acceleration of COG when performing uchimata, The trend of subject YH was showed fast vertical direction in kuzushi and tsukuri, ant-post. and vertical direction fast in kake. The trends of SDK showed lateral direction in kuzushi, lateral and ant.-post. direction in tsukuri and ant.-post direction in kake, respectively.

유도 업어치기 패턴에 따른 하지의 운동학적 분석

김의환,정재욱,강선영,윤현 龍仁大學校 武道硏究所 2002 武道硏究所誌 Vol.13 No.1

The purpose of this investigation was to analyze the changes of the lower limbs angle, when performing Morote-Seoinage(M.S.N.:two arm shoulder throw) in judo who was 5 females university representative judokas of light weight category in judo, and filmed on video cameras(60field/s). The data of this study digitizied by KWON3D 2.1 program computed the average and standard deviation calculated individual 5 trials with Programing Lab view 6i. From the data analysis & discussion, the following conclusions were drawn : 1) A pattern : Right vknee angle was flextion and extension Kuzushi phase and flexed in Tsukuri to Kake phase. Light knee angle flexed in the whole phase. Right·Light hip angle weren't difference changle of angle. 2) B pattern : R. knee angle had flextion and extension in Kuzushi phase and flexed in Tsukuri to kake phase. Light knee angle slowly flexed in the whole phase. Suddenly, flexed in Kake 1·2 stage. Right hip angle raised flextion and extension in Kuzushi phase and suddenly flexed in Tsukuri to Kake phase. Light hip angle slowly raised in the whole phase. 3) C pattern : C pattern was larger than A, B pattern's change of Right knee angle, this time angle was 30.4˚. Light knee angle was flextion in the whole phase. Right hip angle flexed in Kuzushi phase and largely extended, again flexed. Light hip angle firstly flexed and extended, flexed on the Tsukuri to Kake phase.

유도 전방회전낙법 동작의 키네메틱 분석

김의환,윤현,정재욱 龍仁大學校 武道硏究所 2003 武道硏究所誌 Vol.14 No.1

The purpose of this study was to analyze kinematic variable at the time of Judo obstacle forward rolling breakfall. To do so, three dimensional kinematic variable at the time of Judo forward rolling breakfall motions was calculated on five model males of Y university, and, time C. O. G. variable were established. That was standardized using cubic spline interpolation based on the maximum motions time by calculating average value and standard deviation per each factor. As a result of this analysis, I reached following conclusion. 1. Time variable At the time of Judo forward rolling breakfall motions, the total required time was 0.93 seconds, and to describe per phase: at the second phase, air phase, 0.50 seconds(54%): at the third phase, completion phase, 0.36 seconds(38%); and the first phase, take-off phase, 0.08(8%) seconds. 2. C. O. G. variable Left(0.01m)·front(0.26m)·up(0.13m) moved at take-off phase, and left(0.09m)·front(1.46m)·up(0.32m) moved at air phase, and left(0.15m)·front(3.79m)·down(0.71m) moved at breakfall phase. In conclusion, all the subjects conducted bending and stretching exercise and made the center move for jumping higher at take-off phase, assumed motions to keep balance at air phase, and assumed motions for widening base surface by lowering the center and extending the joint of the knee to reduce an impact and assume stable posture at breakfall phase.

고온 초전도체 REBa₂Cu₃O(RE=Yb, Y, Eu, Nd)의 초전도성에 관한 연구

김채옥,김재욱 漢陽大學校 基礎科學硏究所 1992 基礎科學論文集 Vol.11 No.-

고온 초전도체 REBa₂Cu₃O??(RE=Yb, Y, Eu, Nd)의 시료들을 제조하여 결정구조와 적외선 투과율 실험을 상온에서 수행하였고, 온도에 따른 전기 저항의 변화와 자화를 측정하였다. RE의 이온 반경이 증가할수록 초전도체의 전이온도 범위가 커지며, 이는 적외선 투과율 실험에서 Cu-O mode에 의한 frequency의 증가하는 것과 일치됨이 관찰되었다. 자기 임계 전류밀도는 10³~10⁴A/㎠범위에 있었다. 고온 초전도체 REBa₂Cu₃O??에서는 희토류 자성 불순물이 전이온도 Tc에 크게 영향을 주지 않았다. High Tc superconductor REBa₂Cu₃O??(RE=Yb, Y, Eu, Nd)were prepared by solid state reaction. X-ray pellet diffraction and IR transmittance measurements were conducted at room temperature. Also the temperature dependence of the electrical resistance and magnetization was determined. The width of the transition between the normal and the superconduction state was observed to be broader as the radii of the ions. This result agrees with the observed increase in the frequency of transmission due to Cu-O modes. Magnetic critical current densities ranged from 10³~10⁴A/㎠. The localized rare earth magnetic impurities did not affect significantly the transition temperature(Tc) of high Tc superconductor REBa₂Cu₃O??(RE=Yb, Y, Eu, Nd).

핀층의 두께변화에 따른 NiO/NiFe/Cu/NiFe Spin-Valve Sandwiches의 자기저항 특성

김채옥,김재욱 漢陽大學校 自然科學硏究所 1997 自然科學論文集 Vol.16 No.-

NiO 반강자성 박막을 이용한 spin-valve sandwiches 박막을 제작하여 NiO 반강자성층에 인접되어 있는 핀층의 두께변화에 따른 스핀밸브 박막의 구조와 자기저항 특성을 조사하였다. 핀층의 두께가 증가함에 따라 NiFe(111)과 NiO(111)의 XRD피이크의 강도가 커짐을 알 수 있었다. NiO기저층과 인접한 NiFe 자성층이 강한 교환이방성 결합을 함으로써 보자력이 작은 표면 NiFe 자성층은 7∼20Oe 범위에서 자화반전이 유도되어 저자장에서 민감한 자기저항 변화를 나타냈다. NiO/NiFe/Cu/NiFe 박막은 핀층의 두께변화에 따라 3.3∼3.5%의 자기저항비와 2%/Oe 이상의 큰 자장감응도를 보였다. Structural, magnetic and magnetoresistive properties in spin-valve sandwiches with various thickness of pinned layer in contact with the antiferromagnetic NiO film were investigated. The intensities of NiFe(111) and NiO(111) XRD peak were increased with increasing pinned layer thickness. The NiFe layer in contact with the NiO film was pinned by strongly exchange-biased coupling and the free NiFe layer at the film surface induced a sharp change in the magnetoresistance ratio in the range of 3.3∼3.5% and a field sensitivity above 2%/Oe with various thickness of pinned layer.

일부 출판업 VDT 작업자들의 근골격계질환 자각 증상 호소율과 관련요인에 관한 연구

채창호,김영욱,이철호,김정일,김준연,이세훈 가톨릭대학산업의학센타 산업의학연구소 2003 韓國의 産業醫學 Vol.42 No.2

Objectives: This study was conducted to investigate the relationship between the self-reported musculoskeletal symptom prevalence and related factors among some VDT workers in publishing industries. Methods: The 201 study subjects consist of 130 VDT workers comprised of 59 edition workers and 71 data entry workers, and 71 Non-VDT workers. The study subjects were surveyed with structured self-reported questionnaire. Results: The prevalence of self-reported musculoskeletal symptom were 39.2% at neck, 36.2% at back and waist, 30.8% at shoulder, 25.4% at hand and wrist and 9.2% at arm on VDT workers. In logistic regression analysis. Type of VDT(data entry worker) work was related factor of musculoskeletal symptom prevalence at neck, shoulder, arm, back and waist, hand and wrist. VDT working time and working condition were related factors at back and waist. At neck, shoulder, hand and wrist, sex was one of the related factors. Conclusion: Our finding revealed that sex and type of VDT work were main related factors of musculoskeletal symptom prevalence in study subjects.

T1 전송로의 고장 상태 감시를 위한 연구

김세영,이채욱 大邱大學校 科學技術硏究所 1995 科學技術硏究 Vol.2 No.2

Although the number of subscribers for mobile communication is geometrically increasing, T1 transmission line is not able to be sensed because it does not have a visible and audible function when it is down. For this reason, it has caused serious problems in the development of mobile communication. While finding out the cause for trouble, moreover, the technician dispatch is causing various problems such as the waste of expenses and labor and noncontrol of troubles. To solve these problems, this study was conducted by suggesting and devising the monitoring unit using the multi T1 monitor. As the result of this study, it was possible to early find out not only trouble of the T1 transmission line but also its down and recovery times, and to easily control its trouble time.

용매변화에 따른 Polypyrrole 필름의 가공 및 특성

김채옥,김재욱 漢陽大學校 自然科學硏究所 1997 自然科學論文集 Vol.16 No.-

도데실벤젠슬포닉산과 나프탈렌슬포닉산을 도판트로 사용하여 여러가지 유기용매(m-cresol, chloroform, NMP, DMSO 등)로 용해시켜 폴리피롤 free standing 필름을 제조하였고 이들 필름의 흡수 스펙트라, 결정성 및 전기전도도에 대하여 조사하였다. UV-VIS/NIR 스펙트라에서 도데실벤젼슬포닉산을 도판트로 사용한 폴리피롤은 금속적 특성인 free carrier tail 현상이 m-cresol과 chloroform의 유기용매에서만 나타났으나 나프탈렌슬포닉산을 도판트로 사용한 경우는 m-cresol, chloroform, NMP, DMSO 등의 모든 용매에서 free carrier tail 현상이 나타났다. 도데실벤젠슬포닉산과 나프탈렌슬포닉산을 도판트로 사용하였을 때의 용매 변화에 따른 free standing 필름의 결정성 변화는 볼 수 없었다. 또한 도데실벤젠슬포닉산과 나프탈렌슬포닉산을 도판트로 사용한 폴리피롤 필름들의 전기전도도의 값은 유기용매 변화에 따라 각각 0.01∼55/cm와 0.01∼0.65/cm의 범위에 있었다. Polypyrrole free standing films cast from dodecylbenzensulfonic acid(DBSA) and naphthalenesulfonic acid(NSA) dopant were prepared by various solvents(m-cresol, chloroform, NMP, DMSO, etc). The properties of these film such as absorbance spectra, crystallinity and electrical conductivity were investigated. From the UV-VIS/NIR absorbance spectra, the HDBSA doped polypyrrole films cat from m-cresol and chloroform solvents showed the free carrier tail phenomena. Also the DSA doped polypyrrole films cast from all solvents showed the free carrier tail phenomena. For thecases of the HDBSA doped polypyrrole films, the degrees of crystallinity were not changed with various solvents. The values of conductivity in the HDBSA and NSA doped polypyrrole films cast from various solvents were in the range of 0.01∼5S/cm and 0.01∼0.6S/cm, respectively.

한국인에서 CC-SIT와 비교한 KVSS Test의 임상적 유용성 평가 : 예비연구 Pilot study

김진국,장현종,임채형,남태욱,심대보 건국대학교 의과학연구소 2003 건국의과학학술지 Vol.13 No.-

Background and Objectives: Sniffin' Sticks test is the test of nasal chemosensory performance based on pen-like odor dispensing devices. KVSS(Korean Version of Sniffin' Sticks) Test was developed as the "Korean olfactory test" using the odorants which are familiar to Korean. Authors evaluated the clinical validity of KVSS Test compared with CC-SIT (Cross-Cultural Smell Identification Test) in Korean. Materials and Methods: The subjects of this study were 25 normosmic volunteers who were divided into five groups according to age. Each group was 5 normosmic volunteers. And they consisted of 12 men and 13 women. KVSS Test and CC-SIT were used for the evaluation of olfactory function. Results: Our study showed the negative correlation between age and olfactory function test (CC-SIT score, KVSS Test I score and KVSS Test II score). Normosmia rate of KVSS Test was more higher than that of CC-SIT. Also KVSS Test had more familiar items for Koreans compared with that of CC-SIT. CC-SIT score and KVSS Test score showed showed the positive corrclation. And each test revealed high reliability in test-retest evaluation. Conclusion: The KVSS Test can be used as an olfactory function test for Koreans.