• Journal of Korean Neurosurgical Society
• /
• 제50권3호
• /
• pp.209-215
• /
• 2011

Objective : The authors investigated the changes of cortical sensorimotor activity in functional MRI (fMRI) and functional recovery in spinal cord injury (SCI) patients who had been treated by bone marrow cell transplantation. Methods : Nineteen patients with SCI were included in this study; ten patients with clinical improvement and nine without. The cortical sensorimotor activations were studied using the proprioceptive stimulation during the fMRI. Results : Diagnostic accuracy of fMRI with neurological improvement was 70.0% and 44.4% for sensitivity and specificity, respectively. Signal activation in the ipsilateral motor cortex in fMRI was commonly observed in the clinically neurological improved group (p-value=0.002). Signal activation in the contralateral temporal lobe and basal ganglia was more commonly found in the neurological unimproved group (p-value<0.001). Signal activation in other locations was not statistically different. Conclusion : In patients with SCI, activation patterns of fMRI between patients with neurologic recovery and those without varied. Such plasticity should be considered in evaluating SCI interventions based on behavioral and neurological measurements.

• 한국재료학회지
• /
• 제18권10호
• /
• pp.552-556
• /
• 2008

Modified thermal annealing was applied to the activation of the polycrystalline silicon films doped as p-type through implantation of $B_2H_6$. The statistical design of experiments was successfully employed to investigate the effect of rapid thermal annealing on activation of polycrystalline Si doped as p-type. In this design, the input variables are furnace temperature, power of halogen lamps, and alternating magnetic field. The degree of ion activation was evaluated as a function of processing variables, using Hall effect measurements and Raman spectroscopy. The main effects were estimated to be furnace temperature and RTA power in increasing conductivity, explained by recrystallization of doped ions and change of an amorphous Si into a crystalline Si lattice. The ion activation using rapid thermal annealing is proven to be a highly efficient process in low temperature polycrystalline Si technology.

• 멤브레인
• /
• 제7권4호
• /
• pp.183-190
• /
• 1997

Composite membranes were prepared by the deposition of pentafluoropyridine(PFP) or pentafluorotoluene(PFT) plasma films onto porous Celgard and nonporous poly(dimethylsiloxane) [PDMS] films. Gas permeation measurements for the composite membranes were made in the temperature range of 35$^{\circ}$C to 75 $^{\circ}$C and the solubilities in plasma polymers were measured using a Cahn Microbalance. The permeability coefficients of plasma polymers obeyed the Arrhenius relationship fairly wall. Activation energies for permeation in the plasma films increased with the size of penetrant molecules. The activation energy of plasma polymers was much lower than that of commonly used perfluoropolymers. This difference was proved to be attributable to the much lower heat of solutions of the plasma polymers compared to perfluoropolymers. The diffusion activation energies were comparable with each other.

• 대한통합의학회지
• /
• 제6권4호
• /
• pp.91-100
• /
• 2018

Purpose : The study investigated the effects of Pilates exercise on strengthening trunk muscles of females who perform such exercise for the purpose of comparing activation of trunk muscles that contact while performing Pilates motions between females with or without at least 8 weeks of Pilates experience. Methods : The study investigated 10 females with at least 8 weeks of Pilates experience in the past 6 months (experienced group) and 10 healthy females without Pilates experience (non-experienced group). The study used basic Pilates postures involving hip abduction, lift, and leg swing motions as the measurement postures in comparing the activation of muscles used for stabilization, such as the rectus abdominis, external oblique abdominal, and transverse abdominis & internal oblique abdominal muscles. Surface electromyography was used for measuring muscle activation, and the measurements targeted activation of the rectus abdominis, external oblique abdominal, transversus abdominis, and internal oblique abdominal muscles. Results : The study results showed that, as compared to the non-experienced group, the experienced group had significantly higher muscle activation in the transverse abdominis and internal oblique abdominal muscles during hip abduction (p<.05) and significantly higher muscle activation in the rectus abdominis, external oblique abdominal, and transverse abdominis & internal oblique abdominal muscles during lift and leg swing motions (p<.05). Conclusion : Pilates exercise performed over a long period can be recommended as an effective exercise method that can increase the activation of trunk muscle, and especially, repeated performance of highly difficult motions can increase muscle activation even more, which can help promote spinal stabilization, prevent pain, and improve performance of activities of daily living.

• 한국전기화학회:학술대회논문집
• /
• 한국전기화학회 2002년도 연료전지심포지움 2002논문집
• /
• pp.211-218
• /
• 2002

In this study, Pt/Pd (1.1), PtPd (2:1) and PtPd (3:1) binary catalysts and Pt/Ru/Pd (5:4:1) ternary catalyst were designed. The catalysts were synthesized by impregnation method using $NaBH_4$ as a reducing agent. A good catalyst for methanol oxidation requires low on-set potential, stable durability and low activation energy. In order to investigate the catalytic activity for the methanol oxidation, electrochemical measurements such as cyclic voltammetry and chronoamperometry were peformed in sulfuric acid with/without methanol solution. In order to calculate the activation energy of the reaction, electrochemical measurements were also tested at different temperatures. For investigation of the structural analysis such as particle size and alloying, X-ray diffraction and transmission electron microscopy analysis were used. In order to identify the role of the Pd and to determine the composition of the surface of the Pt/Pd nanoparticles, X-ray photoelectron spectroscopy (XPS) analysis was investigated. The XPS spectra of Pd showed that Pd appears only as a metallic state in the binary catalysts. The chemical states of Pt in PtPd catalysts are both metallic and oxidative. Polarization curves and power density data were obtained by testing the DMFC unit cell performance of PtPd and PtRuPd catalysts. These data showed that Pt/Pd (2:1) and Pt/Ru/Pd (5:4:1) have better performance than Pt and Pt/Ru, respectively.

• 열처리공학회지
• /
• 제18권5호
• /
• pp.312-317
• /
• 2005

The precipitation process in Cu-0.2 wt.%Cr-0.05 wt.%Zr alloys has been studied by electrical electrical resistivity measurements. The kinetics of precipitation could be well described by Johnson-Mehl-Avrami equation, $f(t)=1-\exp(-kt^n)$. The values of n were found to be in the range of 0.36~0.42 at first stage and 1.3~1.6 at second stage. The activation energy was determined by cross-cut method and was 80~89 kJ/mol. The value is similar to the energy for the migration of either a vacancy or a vacancy-solute complex through the lattice.

• 대한물리의학회지
• /
• 제12권1호
• /
• pp.1-8
• /
• 2017

PURPOSE: This study was to determine the changes of abdominal muscles activation according to the heel contact methods of stair ascent in healthy young adults. METHODS: 33 healthy young subjects (mean age: $26.37{\pm}9.72$ years, age range: 20-32 years) volunteered under two conditions. They were performed stair ascent with heel contact and without heel contact. The effects of heel contact methods were assessed using the surface electromyography (sEMG) analysis during stair ascent for activation of abdominal muscles (internal oblique; IO, transverse abdominis; TrA, external oblique; EO rectus abdominis; RA). The interventions were conducted over three trials in each method, and measurements were performed on each subject by one examiner in three trials. RESULTS: Our results revealed that there were significantly greater increase in the EMG activation of IO and TrA muscles in the performance of stair ascent with heel contact (p<.05) compared to those of stair ascent without heel contact. The results also showed that there were greater decrease in the ratio of abdominal muscle activation in those of stair ascent with heel contact compared with stair ascent without heel contact. CONCLUSION: These findings demonstrated that the method of stair ascent with heel contact would suggest positive evidence for improving activation of abdominal muscles.

• KIEE International Transactions on Electrophysics and Applications
• /
• 제2C권6호
• /
• pp.281-286
• /
• 2002

The temperature accelerated dielectric breakdown strength of on-wafer low-k dielectric polymer films with thicknesses ranging from 94 nm to 1141 nm is investigated by using the current-voltage characteristic measurements with MIS structures. The temperature dependence of dielectric strength is demonstrated to be Arrhenious for all thicknesses. However, the activation energy is found to be strongly thickness dependent. It follows an exponential relationship rather than being a single value, i.e., the activation energy increase significantly as film thickness increases for the thickness below 500 nm, but it is almost constant for the thickness above 500 nm. This relationship suggests that the change of the activation energy corresponding to different film thickness is closely related to the temperature dependence of the electron trapping/detrapping process in polymer thin films, and is determined by both the trapping rate and the detrapping rate. Thinner films need less energy to form a conduction path compared to thicker films. Hence, it leads to smaller activation energy in thinner films, and the activation energy increases with the increase in film thickness. However, a nearly constant value of the activation energy is achieved above a certain range of film thickness, indicating that the trapping rate and detrapping rate is almost equal and eventually the activation energy approaches the value of bulk material.

• 한국광물학회지
• /
• 제18권4호통권46호
• /
• pp.237-248
• /
• 2005

[ $Mg_{2}SiO_{4}{-}$ ]스피넬에서 올리빈으로의 역상변이에 대한 고온 X-선 회절실험 결과, 진공상태에서 가열하였을 때 상변이가 일어나며, 일정한 온도에서 스피넬상으로부터 올리빈상이 시간이 경과하면서 성장하는 것으로 보아 상변이 메커니즘은 '핵생성 및 성장' 형태인 것으로 판단된다. 스피넬 상으로부터 올리빈 상으로 역상변이 할 때의 활성화 에너지를 구하기 위해 $Mg_{2}SiO_{4}{-}$스피넬 시료에 대한 상변이 실험을 진공 및 고온($1023\∼1116\;k$)에서 시행하였다. 올리빈 상에 대해 '주어진 시간에 따른 비분율법'을 이용하여 활성화 에너지 값을 결정하였다. 아브라미 방정식을 이용하여 계산한 결과, n값은 대체로 온도가 증가함에 따라 매우 넓은 영역에서 동반 상승하는데, 이러한 현상은 '핵생성 및 성장' 메커니즘이 아마도 온도에 종속적이지 않느냐 하는 것을 제시해주고 있다. 상대적으로 낮은 온도에서는 $Mg_{2}SiO_{4}{-}$스피넬은 핵이 생성된 자리가 포화된 후, 새로운 결정상이 표면에서 성장을 시작하고 시간이 지남에 따라 내부 쪽으로 옮아가는 것으로 판단된다. 그러나 고온에서, 성장은 핵이 생성된 자리가 포화되고 난 후 표면뿐만 아니라, 내부에서도 동시에 시작되는 것으로 보인다.

• 감성과학
• /
• 제11권4호
• /
• pp.637-644
• /
• 2008

감성을 인식하고 반응하는 감성컴퓨터를 개발하기 위한 감성인식에 대한 연구가 활발하다. 본 연구는 2차원으로 정의한 감성을 측정하기 위해서 시간에 따른 생리신호의 반응 변수를 정의하고 그 변수로 인한 감성을 구분하고자 하였다. 10명의 대학생에게 16장의 감성을 유발시킬 수 있는 이미지를 제시하였다. 그리고 자율신경계 반응으로 ECG(electrocardiogram), PPG(photoplethysmogram), GSR(Galvanic skin response), RSP (respiration), 그리고 SKT(skin temperature)를 측정하였다. 본 연구는 자율신경계 반응에 대해 Delay, Activation, Half recovery 그리고 Full recovery로 이루어진 TDP(Time Dependent Parameters)를 정의하고 감성을 구분할 수 있는지에 대한 통계적 유의성을 검증하였다. 그 결과, TDP가 감성을 구분할 수 있는 유의미한 변수로 확인하였고 특징적 경향을 보임을 알 수 있었다. 그러므로 본 연구는 TDP가 감성 인식을 위한 유효한 변수일 가능성을 보였다.