BaTiO₃PTC 소자와 진공 열증착된 Al 전극의 접촉 특성

권혁주,전본근,이재성,이용수,이용현 경북대학교 센서기술연구소 1992 센서技術學術大會論文集 Vol.3 No.1

Coevaporation에 의한 cd₁-xZn_(x)S 박막 제작 및 특성에 관한 연구

李載亨,李虎烈,朴鏞冠,申成浩,申載爀,朴光子 성균관대학교 1998 학술회의지원논문목록집 Vol.1998 No.-

In this paper, structural optical and electrical properties of Cd_(1-x)Zn_(x)S thin films prepared by coevaporation method were studied. Also, effects of ZnS mole ratio(x) to CdS on properties of thin film Cd_(1-x)Zn_(x)S/CdTe solar cells were investigated. When the ZnS mole ratio was less than 0.85, the crystal structure of Cd_(1-x)Zn_(x)S films was hexagonal with the c axis aligned perpendicular to the substrate. For x>0.85, however, the Cd_(1-x)Zn_(x)S films were grown with cubic zincblende structire. As the ZnS mole ratio increased the lattice constant of Cd_(1-x)Zn_(x)S films rapidly increased with ZnS mole ratio. The open circuit voltage of Cd₁xZnxS/CdTe solar cells increased with x due to reducing of the electron affinity difference between Cd₁xZnxS and CdTe films. However, the increase of series resistance due to the high resistivity of Cd_(1-x)Zn_(x)S films results on reducing conversion efficiency.

인스텝 슛팅 동작에 대한 운동학적 분석

이용구,김무영,이한혁,조현영 한국스포츠리서치 2003 한국 스포츠 리서치 Vol.20 No.1

The purpose of this study was to investigate the kinematic variables of the lower extremity during the Soccer In-step shooting motion. To conduct an investigation, five soccer players(skill group) and five students(less-skill group) in the high school were participate in this study. They were videotaped using three video cameras with the frame rate being 60㎐. This data was then reducted to 3D coordinates using the DLT(direction linear transformation)method. It was concluded that; Medio-lateral(X) displacement of the skill group was larger than that less-skill group and antero-posterior(Y) displacement of the skill group was smaller than that less-skill group. Velocity transfer of the skill group was more effectiveness than less skill group. The sequence of the maximal joint velocity of the kicking leg was the hip, knee, and ankl joint. It is considered very important that the sequence of the laximal joint velocity is from the proximal to the distal in order to increase the foot velocity at the impact. Trunk angle of the skill group was smaller than that less-skill group. And then ankle joint angle of the skill group was larger than that less-skill group.

The effect of cooling rate on electrical properties of ZnO varistor for Fire Alarm Circuit

Lee,Duck-Chool,Kim,Yong-Hyuk,Chu,Soon-Nam 한국화재소방학회 1996 한국화재소방학회논문지 Vol.10 No.4

본 연구에서는 화재 감지 회로 등에 사용되는 ZnO 바리스터의 제조과정중 냉각 속도가 전기적 특성에 미치는 영향에 대하여 조사한 것이다. 냉각 속도의 변화에 따른 시편의 미세구조, 전압-전류 특성, 복합임피던스 측정을 하였다. 냉각 속도 <TEX>$200^{\circ}$</TEX>/h에서 비오옴계수나 바리스터 동작 전압의 최대치를 나타내었다. 이것은 냉각과정 중 형성된 결정입계에 성질에 의존됨을 알았다. 복합임피던스는 100Hz-13MHz의 주파수 범위에서 측정하였으며, 반원의 특성을 검토한 결과 결정립이나 결정입계의 저항이 냉각 속도에 크게 의존되고 있음을 확인하였다. The aim of the present study is to find out the effect of cooling rate on the electrical behavior of ZnO varistors. The microstructure, 1-V characteristics and complex impedance spectra were investigated under the change of cooling rates. It is found that at cooling rate <TEX>$200^{\circ}$</TEX>/h, nonlinearity and breakdown voltage reached a maximum value which may show that good intergranular layer is formed as a results of proper cooling rate. Complex Impedance spectras were measured as a function of frequency range 100Hz to 13MHz to determine grain and grainboundary resistance. The semicircles were attributed to the dependence of grain and grainboundary resistance on cooling rates.

요중 비소농도와 N-acetyl-β-D-glucosaminidase 농도와의 관련성 평가

이용찬,임동혁,엄상용,김용대,김헌 충북대학교 의과대학 충북대학교 의학연구소 2010 忠北醫大學術誌 Vol.20 No.1

Purposes: This study was performed to evaluate the possibility of impairment of renal tubular function by exposure to inorganic arsenic of low concentration. Materials and methods: Study subjects were 867 individuals (365 men and 502 women) who resided around abandoned mine areas in Chungbuk Province, Republic of Korea. Information about the life style, drinking water type, seafood intake, and mine working history was gathered, and urinary arsenic concentration and N-acetyl-β-d-glucosaminidase (NAG) activity were measured. The correlation between arsenic concentration and urinary NAG activity was tested in groups classified according to urinary NAG activity and seafood consumption prior to urine sampling. Results: No statistically significant difference in urinary arsenic concentrations was observed between different gender and age groups. The participants those who ate seafood within three days before the urinary sample showed a higher mean urinary arsenic concentration than those who did not. In a correlation analysis between natural logarithm of urinary arsenic concentrations and that of urinary NAG activities, no statistical significance was found in a total sample as well as within a gender group. In a group with the urinary arsenic concentrations higher than the geometric mean and the urinary NAG activities higher the geometric mean, the correlation coefficient between two variables was 0.182 and significant. (p-value<0.05) Conclusions: It is suggested that renal tubular damage could be induced by non-occupational exposure to low level inorganic arsenic. 연구목적 : 본 연구는 폐금속광산 주변지역 주민들을 대상으로, 저농도 비소노출에 의하여 신세뇨관 기능이상이 유발될 수 있는지를 평가하는 것을 목적으로 시행하였다. 대상 및 방법 : 충청북도에 소재하고 있는 폐금속광산의 주변에 거주하는 주민 867명을 대상으로 직접 면접조사를 실시하였다. 대상자의 소변을 채취하여 요중 비소농도와 요중 N-acetyl-β-D-glucosaminidase (NAG) 활성을 측정하였고, 조사대상자를 역학적 변수에 따라 구분하여 두 변수 사이의 상관관계를 분석하였다. 결과 : 소변시료를 채취하기전 3일 이내에 해산물을 섭취한 사람들의 요중 비소농도는 그 기간동안 해산물을 섭취하지 않은 사람들의 농도에 비하여 유의하게 높았다. 조사 대상자들의 요중 NAG 농도의 평균값은 남녀차이가 없었으나, 65세 미만 대상자와, 표본을 채취하기 전 3일 이내에 해산물을 섭취한 사람들의 요중 NAG 활성도의 평균값은 그렇지 않은 사람들에 비하여 유의하게 낮았다. 요중 비소농도가 기하평균 이상이고, 요중 NAG 활성이 기하평균 이상인 군에서 두 변수의 상관관계가 0.182 로 유의하였다. 결론 : 정상범위의 비소 노출이라도 요중 비소농도가 8.28 μg/g creatinine을 초과하는 경우에는 미세한 신장손상을 유발할 가능성이 있으며, 해산물을 섭취함으로써 체내에 흡수되는 비소는 이러한 신독성이 거의 없다.

뇌졸중 후 치매환자에서 도네피질(아리셉트^(?))이 인지기능 및 일상생활 수행능력, 삶의 질에 미치는 효과

이상열,장혁,송재은,조성옥,류정미,이미경,조진호,신용일 圓光大學校 醫科學硏究所 2008 圓光醫科學 Vol.23 No.1

Background: This study evaluated the efficacy of administering Donepezil(Aricept^(?)) for improving cognitive function, activities of daily living, and quality of life in patients with post-stroke dementia. Methods: Patients(n=99; mean age, 69.89 years; 48.5% men) with post-stroke dementia, according to criteria of the DSM-IV and MRI, were treated with donepezil 5mg/day or 10mg/day during 24 weeks. They were examined using Mini-mental Status Examination(MMSE), Chinical Dementia Rating(CDR), Barthel Activities of daily living(B-ADL), Instrumental Activities of daily living(I-ADL), Short Form 36 Health Survey-Korean(SF-36-K), and Geriatric Depression Scale(GDS) at before treatment and 24 weeks after treatment. Results: The 97 patients completed the trial. At 24 weeks, they showed significant improvement in MMSE(p<0.001), CDR(p<0.001), B-ADL(p=0.002), I-ADL(p<0.001), and SF-36-K(p=0.003) except GDS(p=0.288). Donepezil was well tolerated. There was no withdrawal due to adverse events. Conclusion: This results demonstrate that donepezil was beneficial in improving the cognitive function, activities of daily living, and quality of life in patients with post-stroke dementia and was well toleraetd.

뇌자도 측정을 위한 저잡음 Nb SQUID 센서의 설계 및 제작

이용호,권혁찬,김진목,이상길,임청무,박용기,박종철 경북대학교 센서기술연구소 1998 센서技術學術大會論文集 Vol.9 No.1

We report on the design, fabrication and performances of a low-noise Nb SQUID sensor for neuromagnetic measurements. The main features of the developed sensor are i) large flux-to-voltage transfer, making the SQUID readout electronics simple, and ii) use of the integrated planar pickup coil to eliminate the environmental magnetic field noises. The magnetic field noise of the developed SQUID sensor is below 5 fT/√Hz at 100 Hz, which is low enough to be used in neuromagnetic measurements.

마이크로 컨트롤러를 이용한 지능구조물의 진동제어시스템 개발

황재혁,홍의표,이원석,최용훈 한국항공대학교 항공우주산업기술연구소 2003 航空宇宙産業技術硏究所 硏究誌 Vol.13 No.-

본 논문에서는 유연구조물의 진동을 제거하기 위하여 압전 세라믹(PZT)을 감지기와 작동키로 이용하였다. 진동을 제거하기 위한 제어 방법은 위치 되먹임 제어와 속도 되먹임 제어 두가지 방법을 사용하였다. 위치 되먹임 제어는 구조물의 각 지점의 위치를 감지해 내고 이를 역으로 걸어 주는 것이고 속도 되먹임 제어는 유연부착물의 각 지점에서의 속도에 대한 정보를 역으로 걸어 주는 것이다. 즉, 압전 감지기의 감지 전압을 이용해서 속도 되먹임 제어를 할 수 있다. 적용된 두 제어 방법 모두 개회로일 때 보다 좋은 성능을 나타내었다. 그러나 위치 되먹임 제어가 스필오버(spill-over)가 심했고 속도 되먹임 재어보다 정착시간(Settling Time)이 더 길었다. 본 실험에서는 속도 되먹임 제어가 적은 에너지로도 위치 되먹임 제어보다 좋은 성능을 보였다. 제어시스템을 구축하기 위해서 마이크로 컨트롤러를 사용한 제어보도를 설계하고 제작하였다. 제어 보드에 사용된 마이크로 컨트롤러는 Intel 80c196ke를 사용하였으며 마이크로 컨트롤러의 A/D, D/A 기능을 보완하기 위해서 A/D, D/A 보드를 제작하였으며, 사용자 편의와 원거리 제어를 위해서 사용자 보드를 제작하였다. 본 실험에서 제작한 제어 보드는 본 실험에 쓰인 외괄보 뿐만 아니라 압전 세라믹을 이용한 모든 구조물의 능동진동제어에 쓰인 수 있도록 제작되었다.

염산증기 흡입에 의해 발생한 화학성 폐렴 1예

장재혁,원경준,권세훈,하성일,권용은,이승일,윤성호 朝鮮大學校 附設 醫學硏究所 2007 The Medical Journal of Chosun University Vol.32 No.2

A 38-year-old man with dyspnea admitted to the emergency department after exposure to hydrochloric acid in pharmaceutical product manufacturer. Crackle was auscultated in both lung fields in initial physical examination. Chest radiograph showed consolidation and diffuse parenchymal infiltration in both lung fields. Arterial blood gas analysis showed severe hypoxia. This patient was treated by mechanical ventilation, corticosteroid, antibiotics and bronchodilators and was improved completely in a week after the admission. The authors report a rare case of chemical pneumonitis caused by hydrochloric acid.

자동차용 컨트롤 링크 업셋 용접부의 용접성 및 피로강도 향상에 관한 유한요소 해석

조해용,권혁홍,이봉규 한국공작기계학회 2001 한국생산제조학회지 Vol.10 No.6

This study is concerned with Finite Element Analysis on welded part of control link for automobile. For analysis, control link was modeled into two parts, ring and rod. Heating condition, temperature distributions and fatigue fracture strength were analyzed using "HEAT Ⅲ" and "ENDURE" module of NISA Ⅱ. Metal flow in the process of welding was simulated by DEFORM^TM 2D. The analyzed results were compared with experimental inspection. Quality of welded part was able to be improved by controlling metal flow in the process of welding by increase the friction constant of ring part. Heat transfer analysis and flow simulations were in good agreement with welding experiments.