스피넬 구조의 전이금속산화물의 전자구조 계산

송현철,박기택 국민대학교 2003 기초과학연구소 논문집 Vol.22 No.-

국소밀도 근사를 이용한 범밀도 함수법을 기초로 한 Full Potential Linear Augmented Plane Wave(FLAPW) 방법을 이용하여 spinel 구조를 갖는 MnFe₂O₄, CoFe₂O₄, FeCr₂O₄의 전자구조 및 자기적 성질을 연구하였다. 그리고 LDA+U 방법을 사용하여 LDA 방법과의 비교를 수행하였다. 계산 결과 MnFe₂O₄에서 Fe 원자는 high spin 상태를 보여 주지 않았다. 이러한 문제는 LDA 계산에서, 특히 철산화물에서 Fe 원자와 O 원자 사이의 결합이 너무 강해 일어 나는 것으로 보여진다. 이러한 문제점을 해결하기 위해 강상관 관계를 가진 철 산화물에서의 개선된 방법이 요구되고 있다. CoFe₂O₄는 정스피넬 구조로 계산을 한 결과 LDA 방법에서는 4.2μ_B, LDA+U 방법에서는 7μ_B의 자기 모멘트를 가졌다. FeCr₂O₄는 절연체 성질을 보이는데 LDA계산을 통한 결과는 금속 성질을 보였다. 이것은 얀-텔러 변환을 고려한 계산을 통하여 절연체의 성질을 설명할 수 있으며, 또 다른 원인으로는 불충분한 전자상관관계를 LDA+U 계산을 통하여 절연체적 성질을 얻어낼 수 있었다. We have studied electronic structures and magnetic properties of MnFe₂O₄, CoFe₂O₄, FeCr₂O₄with spinel structure using Full Potential Linearized Augmented Plane Wave(FLAPW) method based on LDA and LDA+U method. LDA and LDA+U calculation results show that Fe atom does not show high spin state in MnFe₂O₄. It seems to be strong hybridization between Fe and 0 atoms in LDA and LDA+U calculation. It needs improved method in iron oxides with strong correlation. CoFe₂O₄is known to have a inverse spinel structures. The results of calculation with normal spinel structure shows magnetic moment of 4.2μa in LDA, 7μa in LDA+U method. FeCr₂O₄ is insulator, but the LDA calculation result shows the metallic nature. It could be explained by Jahn-Teller effect. However the other factor of insulating nature comes from the Coulomb interaction between electrons. The calculation result of LDA+U shows the insulating gab and orbital ordering of 3y^2-r^2d orbital character.

부하 불평형을 고려한 능동전력피터 성능 연구

이택기,박현식 안성산업대학교 2000 論文集 Vol.32 No.-

This paper presents the performance of a active power filter(APF) system in unbalanced load. The unbalanced load leads to negative sequence of current, and this makes 120㎐ ripple in dc-link voltage and increase the rating of APF. Thus, the separation of negative sequence was performed in synchronous reference frame and it was controlled to flow into supply network. The validity of this scheme is investigated through experimental results for a prototype APF system rated 10kVA.

C-반응성단백과 가장 관련 있는 대사증후군 대사이상 항목

손중천,김범택,이득주,최현국,정현주,김광민 대한비만학회 2003 The Korean journal of obesity Vol.12 No.1

연구배경: C-반응성단백 (이하 CRP)은 심혈관질환의 예후인자 및 독립적 위험인자이다. 대사증후군은 복부비만, 고혈압. 당대사이상 및, 지질대사이상과 같은 관상동맥질환 위험인자들이 동시에 나타나는 증후군을 말한다. 저자들은 18세 이상의 성인 남녀에서 CRP와 대사증후군 대사이상 항목과의 상관관계를 연구하였다. 방법: 2002년 4월부터 10월까지 일개 대학병원 건강증진센터에 내원한 수진자 2772명 중 염증성질환이 의심되는 577명을 제외한 총 2195명을 대상으로 하였다. 신체계측과 혈압측정, 혈액검사를 실시하였다. 통계적 분석은 남녀를 구분하여 대사증루군의 대사이상 항목의 군집성에 따른 CRP값에 대해 ANOVA 검정을 시행하였고, 각 대사이상 항목들과 연령을 독립변수로 하여 회귀분석을 실시하였다. 결과: CRP는 남성에서 0.10 (±0.004) mg/dL, 여성에서 0.08 (±0.003) mg/dL로 남성이 여성보다 유의하게 높았다(p<0.001). 남녀 모두에서 CRP가 대사증후군 군에서 대사증후군이 없는 군보다 유의하게 높았다. 대사증후군의 대사이상 항목 수가 증가할수록 CRP값이 증가하는 양상을 보였다(P for trend<0.001). 남녀 모두에서 허리둘레 (남성 R²=0.132, 여성 R²=0.166)가 가장 높은 설명력을 보였다. 결론: 18세 이상의 성인 남녀 모두에서 CRP는 대사증후군 대사이상 항목들과 유의한 상관관계를 보였다. 대사이상 항목중 허리둘레가 CRP 수치와 상관관계가 가장 높았다 Background: C-reactive protein has been known as an independent risk factor and prognostic factor for cardiovascular diseases. Metabolic syndrome is a sum of coronary risk factors such as abdominal obesity, elevated blood pressure, hypertension, glucose intolerance and abnormalities in lipid level. The previous studies showed limited relationships between CRP and the risk factors in metabolic syndrome. We investigated the relationships between CRP and the risk factors in metabolic syndrome in adult men and women over 18 years old. Methods: This study included 2772 people. 577 people of them found to have inflammatory disease excluded. The anthropometry and blood pressure were measured. High sensitive CRP, Lipid profiles, WBC, and ESR were assessed. Results: CRP in Men (0.10 (±0.004) mg/dL) was significantly higher than that in women (0.08 (±0.003) mg/dL)(P<0.001). In both genders, CRP was significantly higher in people who have metabolic syndrome than in people who don't. As the number of risk factors increased, CRP was significantly increased (P for trend < 0.001). Waist circumference showed the greatest correlation with CRP in men and women (men; R²=0.132, women; R²=0.166) Conclusion: CRP was correlated with risk factors in metabolic syndrome in men and women over 18 years old. Of the risk factors waist circumference was most correlated with CRP.

전위된 관절내 종골 골절의 수술적 치료 후 방사선학적 계측치와 임상 결과와의 관계

손홍문,임만택,문현식 朝鮮大學校 附設 醫學硏究所 2004 The Medical Journal of Chosun University Vol.29 No.3

Objectives: The purpose of our study was to evaluate the relationship between radiographic parameters and clinical results after operative treatment of the displaced intra-articular calcaneal fractures. Materials and Methods: We analyzed 35 patients of unilateral displaced intraarticular calcaneal fractures who had been treated by operative treatment. At the last follow up, we measured the radiographic parameters including Bohler angle, Gissane angle, heel height, calcaneal length, talocalcaneal angle, talar declination angle, and subtalar incongruity between normal and affected site. Clinical results were measured by Creighton-Nebraska Health Foundation Assessment Score (CNH). And then the correlation between the radiographic parameters and the clinical results were analysed by Pearson correlation method. Results: The average difference between normal and affected site were Bohler angle 15˚ (0-35), Gissan angle 6.5˚(0-20), heel height 4.7mm (1-12), calcaneal length 2.0mm (0-7), talocalcaneal angle 5.5˚(1-19), talar declination angle 2.2˚(0-8), calcaneal width 4.0mm (1-9), subtalar incongruity 0.54mm (0-2.5). The correlation coefficients between radiographic parameters and CNH score were Bohler angle 0.066 (p=0.75), Gissane angle 0.038 (p=0.829), heel height 0.019 (p=0.916), calcaneal length 0.091 (p=0.386), talocalcaneal angle 0.059 (p=0.737), talar declination angle 0.118 (p=0.501) , calcaneal width 0.250 (p=0.291), and subtalar incongruity 0.784 (p=0.002) respectively. Among the all radiographic parameters, The subtalar incongruity shows strong linear correlation with clinical results. Conclusion: We suggested that the subtalar incongruity was significantly correlated with the' clinical results after operative treatment of the displaced intraarticular calcaneal fractures.

청각장애인의 슬부 등속성 근력에 관한 연구

장명재,이택현 경희대학교 체육과학연구소 1997 體育學論文集 Vol.25 No.-

The purpose of this study was to investigate and compare knee Isokinetic muscular strength of deaf and normal population. For this purpose, 32 subjects(8 untrained deaf, 8 trained deaf, 8 deaf national athlete, 8 untrained normal) were selected. The results were as followings. 1.The peak torque in time of flexion 60˚/sec(right, left) showed great significant difference(p<.001). 180˚/sec 5, 25 repetitions(left) showed great significant difference(p<.01) and 240˚/sec(right) showed significant differences(p<.05). The peak torque in time of extension 60˚/sec(left) showed great significant difference(p<.07),60˚/sec(right), 180˚/sec 5 repetitions(left),25 repetitions(right. left) and 240˚/sec(right, left) showed significant difference(p<.05). And the others showed no significant difference. The peak torque%body weight in time of flexion 60˚/sec(right) showed great significant difference(p<.01), 60˚/sec(left) showed significant difference(p<.05). The peak torque%body weight in time of extension 60˚/sec(left), 180˚/sec 25 repetitions(left). 240˚/sec(right) showed significant difference(p<.05), 240˚ /sec(left) showed great significant difference(p<.01). And the others showed no significant difference. 3.The total work(BWR)%BW in time of flexion 60˚/sec(1eft) showed significant difference(P<.05). The total work(BWR)%BW in time of extension 60˚/sec(left), 180˚/sec 25 repetitions(left), 240˚/sec(left) showed significant difference(p<.05), And the others showed no significant difference. 4.The average power(BWR)%BW in time of flexion 60˚/sec(right, left) showed great significant difference(p<.01). The average power(BWR)%BW in time of extension 60˚/sec(left), 240˚/sec(left) showed great significant difference(P<.01). 240˚ /sec(right) showed significant difference(P<.05). And the others showed no significant difference. 5.The endurance ratio in time of extension 180˚/sec 25 repetitions(left), 240˚/sec(left) showed significant difference(p<.05). And the others showed no significant difference.

Vitamin D status and its associations with rheumatoid arthritis in Korean women : the Korean National Health and Nutrition Examination Survey 2008–2014

Taeck-Hyun Lee,Woo Sung Jin,Juwon Park,Hyun-Hee Choi,Eun Jin Bae 한국운동재활학회 2016 JER Vol.12 No.6

제14회 아시안게임 남자농구 경기의 승,패 요인 분석

최현희(Hyun Hee Choi),이택현(Taeck Hyun Lee),이종희(Jong Hee Lee),송종국(Jong Kook Song) 한국사회체육학회 2005 한국사회체육학회지 Vol.0 No.24

두 가지 유형의 트레드밀 걷기운동이 만성 편마비인의 보행능력에 미치는 영향

최현희 ( Hyun Hee Choi ),이택현 ( Taeck Hyun Lee ),장명재 ( Myoung Jei Chang ) 대한스포츠의학회 2009 대한스포츠의학회지 Vol.27 No.2

In the present study, the effects of a combination of modified speed-dependent treadmill walking exercise (MSTWE) and body weight support treadmill training (BWS) on the gait of ambulatory chronic hemiparetic stroke patients were investigated. Ambulatory chronic hemiparetic stroke patients in Seoul were examined over a period of 12 weeks (n=28) in a randomized, repeated-measure pilot study. Participants were divided into two group: the MSTWE group, and the MSTWE+BWS group. 13 subjects were enrolled in the MSTWE group and 15 subjects in the MSTWE+BWS group. Treatment outcome assessments were made based on the 10 m gait test. After 12 weeks of MSTWE or MSTWE+BWS 3 times/week, most of the subjects who participated in MSTWE and MSTWE+BWS showed significant restoration in gait speed and stride. Based on the results of the present study, it can be suggested that both of MSTWE and MSTWE+BWS can be used in functional rehabilitation and MSTWE+BWS can be more effective in restoration of stride in chronic hemiparetic stroke patients.

Intensity- and duration-dependence of the treadmill exercise on nitric oxide synthase expression in the hippocampus of rats

Lee Taeck-Hyun(이택현),Jang Mi-Hyeon(장미현),Shin Min-Chul(신민철),Chang Hyun-Kyung(장현경),Lim Baek-Vin(임백빈),Choi Hyun-Hee(최현희),Kim Hong(김홍),Kim Mal-Soon(신말순),Kim Young-Pyo(김영표),Kim Chang-Ju(김창주) 대한스트레스학회 2002 스트레스硏究 Vol.10 No.1

차량용 앞유리 열선의 잠재고장에 대한 고찰

임현택(Hyun-Taeck Lim),위신환(Shin-Hwan Wei),김규로(Gyu-Ro Kim) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.신뢰성 No.-