http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
등척성 운동 시 요추의 각도에 따른 중앙주파수와 토크의 특성
박경희,권오윤,장근,강성재,김영호 한국전문물리치료학회 2001 한국전문물리치료학회지 Vol.8 No.2
Fatigue is the decline in force produced as a result of prolonged muscle activity. Localized muscle fatigue can be identified by a shift toward low in the frequency components of the EMG signal, typically represented by a fall in the median frequency. Previous studies show that a shortened muscle developes a higher fatigue than elongated muscles. The purpose of this study was to investigate the time-related change of median frequency and torque during maximal isometric back extension exercises at different exercise angles (0˚, 12˚, 36˚, 72˚). Twenty healthy subjects (mean age = 24.35 ± 2.70) were evaluated in this study. Median frequency was extracted from the EMG signals by fast Fourier transform (FFT). Initial median frequency and the slope of median frequency change over time were computed from linear regression analysis. Pearson's product moment correlation was used to quantify the relationship between scope of median frequency and torque. The results were as follows: 1) Significant differences in y-intercepts of torque regression equation with respect to exercise angle were shown. However, there were no differences in the slopes of the median frequency and torque, and y intercept of the median frequency among exercise angles. 2) There was no significant correlation between slope of median frequency and torque. 3) But there was moderate correlation between median frequency and torque at each exercise angle. In conclusion, the exercise angle during maximal isometric back extension exercise is not a direct effect on slope of median frequency and torque. But results showed that median frequency and torque shift were highly correlated in all subjects.
수은화합물이 마우스 복강대식세포와 EMT-6 세포에 미치는 효과
고대하,염정호,기노석,오경재,권근상,김성엽,김남송 大韓産業醫學會 1996 대한직업환경의학회지 Vol.8 No.2
Balb/c 마우스의 복강대식세포 및 유선암에서 기원한 EMT-6 세포를 배양하는 조건에 여러농도의 수은을 첨가하여 nitrite와 nitrate 생성의 변화를 관찰한 결과는 다음과 같다. 복강대식세포 및 EMT-6 세포가 생성하는 nitrite와 nitrate 양은 배양시작 12시간째의 생성량에 비해 24시간 후에는 2배, 36시간 후에는 3배의 농도로 측정되어 된다. 이때 nitrite와 nitrate 농도사이에는 매우 높은 상관관계를 나타냈다. 수은첨가에 따라 nitrite 및 nitrate 생성량은 용량의존적 관계로 현저한 감소를 보이며, 24시간 또는 36시간 후의 세포생존률도 역시 수은농도에 비례하여 감소되는데, 복강대식세포의 생존률이 EMT-6 세포의 생존률보다 더욱 큰 폭으로 감소하였다. 이상의 결과로 배양조건에 수은의 첨가로 인하여 nitrite 및 nitrate 생성량이 감소하는 바 수은이 면역세포의 대사과정에 영향을 주어 nitric oxide 생 성능을 억제시키며, 결국 세포성 면역을 저하시키는 것으로 사료된다. The effect of treatment of mercury chloride on the nitrite and nitrate synthesis was observed in peritoneal macrophages from Balb/c mice and EMT-6 cells in vitro. The cells were cultured in Dulbecco's modified Eagle's medium (DMEM) with cytokines. Amounts of nitrite and nitrate in the culture media after 24 and 36 hours of culture were about 2-fold, 3-fold of those measured after 12 hours respectively. There were very close associations between the amounts of nitrite and nitrate measured in the culture media, according to culture time. The survival rate of peritoneal macrophages was significantly decreased by mercury chloride added into the media in dose-dependent manner, however the survivals of EMT-6 cells were not influenced by mercury chloride concentration in media. Nitrite and nitrate syntheses were dose-dependently decreased by mercury chloride added in culture media. These results reported here suggest that the disorder of cell mediated immunity by mercurials could be related to the inhibition of nitric oxide synthesis which seems to be caused by the inhibition of metabolism of cells.
Kwon, Oh Kuen,Jeon, Hong Tae,Hwang, Ho Jung,Kang, Jeong Won American Scientific Publishers 2011 Journal of nanoscience and nanotechnology Vol.11 No.1
<P>Resonant frequencies of cantilevered (8,8)(3,3) double-walled carbon nanotube (DWCNT) resonators are investigated via classical molecular dynamics simulation. The interwall van der Walls forces as a nonlinear function had a great effect on noncoaxial vibration of DWCNT resonators. Bandwidths of DWCNT resonators with short outer walls were similar with each other irregardless to the structural difference. The frequency trends of DWCNT resonators with short outer wall were affected by the outer wall length. The vibration of the DWCNT resonator with short outer wall was very closely related to the vibration of the inner CNT in the stripped region.</P>
Molecular Dynamics Simulations of a C60 Molecule Adsorbed on Sinusoidal Graphene Nanoflake.
Kwon, Oh Kuen,Kang, Jeong Won,Kim, Ki-Sub,Park, Jungcheol American Scientific Publishers 2015 Journal of nanoscience and nanotechnology Vol.15 No.7
<P>We have investigated the motion of a C60 molecule absorbed on sinusoidal graphene nanoflake (GNF) via molecular dynamics simulations. Since C60 deposited on sinusoidal GNF is favorable on energetic grounds, the C60 molecule moved toward one of the valleys of sinusoidal GNF without energy barrier. So no sooner the C60 molecule was deposited on the sinusoidal GNF, then the C60 molecule immediately began to move toward the valley of the sinusoidal GNF Since the position of the C60 molecule can be changed by externally applied force fields and has a binding energy of 0.754 eV in the valley of sinusoidal GNF, the sinusoidal C60/GNF can be applied to a switchable nonvolatile memory device. This work provides the probability of alternative 'bucky shuttle' memory based on the sinusoidal C60/GNF hybrid nanostructure.</P>
Oh Kuen Kwon,이준하,Jungchul Park,Ki-Sub Kim,Jeong Won Kang 한국물리학회 2013 Current Applied Physics Vol.13 No.2
A tunable graphene-nanoribbon (GNR)-resonator was investigated via classical molecular dynamics simulations. Resonance frequencies increased with increasing externally applied gate-force and axialstrain, and could be tuned above several hundred GHz. Tunable resonance frequencies achieved from the gate force were higher than those achieved from the axial-strain. The operating frequencies of GNRresonators without axial-strain or with small axial-strains were most widely tuned by the gate, and almost linearly increased with increasing mean deflection. As the axial strain increased, the tunable ranges of the GNR-resonators were exponentially decreased, although the operating frequencies increased. GNR-resonators without axial-strain could be applied to wide-range-tuners, whereas GNRresonators with high axial-strain could be applied to high-frequency-fine-tuners.
Oh-Kuen Kwon,Myung-Sik Son,Ho-Jung Hwang 한국진공학회(ASCT) 1999 Journal of Korean Vacuum Science & Technology Vol.3 No.1
This paper presents a newly enhanced damage model in Monte Carlo (MC) simulation for the accurate prediction of 3-Dimensional (3D) as-implanted impurity and point defect profiles induced by ion implantation in (100) crystal silicon. An empirical electronic energy loss model for B, BF₂, As, P, and Si self implants over the wide energy range has been proposed for the ULSI device technology and development. Our model shows very good agreement with the SIMS data over the wide energy range. In the damage accumulation, we considered the self-annealing effects by introducing our proposed non-linear recombination probability function of each point defect for the computational efficiency. For the damage profiles, we compared the published RBS/channeling data with our results of phosphorus implants. Our damage model shows very reasonable agreement with the experiments for phosphorus implants.
Kwon, Oh-Kuen,Son, Myung-Sik,Hwang, Ho-Jung The Korean Vacuum Society 1999 Journal of Korean Vacuum Science & Technology Vol.3 No.1
This paper presents a newly enhanced damage model in Monte Carlo (MC) simulation for the accurate prediction of 3-Dimensional (3D) as-implanted impurity and point defect profiles induced by ion implantation in (100) crystal silicon. An empirical electronic energy loss model for B, BF2, As, P and Si self implant over the wide energy range has been proposed for the ULSI device technology and development. Our model shows very good agreement with the SIMS data over the wide energy range. In the damage accumulation, we considered the self-annealing effects by introducing our proposed non-linear recomvination probability function of each point defect for the computational efficiency. For the damage profiles, we compared the published RBS/channeling data with our results of phosphorus implants. Our damage model shows very reasonable agreement with the experiments for phosphorus implants.
Molecular Dynamics Simulation Study of a Nanogun Based on a Partially Unzipped Carbon Nanotube
Kwon, Oh-Kuen,Park, Joon Hoon,Kim, Ki-Sub,Kang, Jeong Won American Scientific Publishers 2016 Journal of nanoscience and nanotechnology Vol.16 No.11
<P>We used classical molecular dynamics simulations to investigate a nanogun formed by the ejection of a C-60 fullerene from a partially unzipped single-walled carbon nanotube (SWCNT). This nanogun can be refilled, and could serve as a key building block for nanoelectromechanical devices. Our simulations show that the preadsorbed C-60 fullerene in the interior of the unzipped SWCNT regionis smoothly encapsulated into either region of the zipped SWCNT. In order to launch the C-60 fullerene through the muzzle of the partially unzipped SWCNT, the C-60 fullerene should overcome two energy barriers: a first energy barrier of 1.1 eV, when the C-60 fullerene escapes from the zipped SWCNT to the unzipped part; and a second energy barrier of 2.6 eV, when the C-60 fullerene is completely ejected from the partially unzipped SWCNT. High muzzle velocities of the C-60 fullerene were achieved, of 0.25 km/s to 0.97 km/s. These results can be useful for the understanding of new molecular machines.</P>