• Physical Therapy Korea
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• v.11 no.3
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• pp.19-24
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• 2004

The purposes of this study were to analyze gait patterns of patients with chronic lumboscaral radiculopathy and to investigate gait parameters which can reflect a functional deficit in relation to the level of lumbosacral radiculopathy. The study population consisted of 25 patients of chronic lumbosacral radiculopathy and 25 healthy control subjects. Conventional physical examinations and three-dimensional gait analyses were performed on all participants. The data were analyzed using an independent sample t-test. The results were as follows: (1) In the patients' group, cadence, walking velocity, stride length and double support time were less than in the control group (p<.05). (2) In the patients' group, maximum flexion of hip, maximum flexion of loading response, maximum flexion of swing phase on the knee and maximum plantar flexion of pre-swing were less than the control group (p<.05). Using three-dimensional gait analysis, we could identify specific gait parameters to reflect a functional deficit related to the level of lumbosacral radiculopathy.

• The Journal of Korean Physical Therapy
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• v.18 no.3
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• pp.1-7
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• 2006

Purpose: This study was performed to determine the difference or temporal-spatial gait asymmetry ratio according to static pelvic inclination level in hemiplegic patients. Methods: The subjects were 25 hemiplegic patients who was experienced stroke on MCA territory. Gait parameters and static pelvic inclination were recorded by $GAITRite^{(R)}$ system and radiologic PACS. The subjects were divided into three group according to static pelvic inclination. In the group I, the subjects have static pelvic inclination below $58^{\circ}$. The group II has $58^{\circ}{\sim}62^{\circ}$ or static pelvic inclination and the group m has over $62^{\circ}$ or static pelvic inclination. The data or three groups were analysed with ANOVA. Results: In comparison or single support time asymmetry ratio among 3 groups, the score or group II was significantly higher than the other groups(p<0.05). But the swing time asymmetry ratio was not significant(p>0.05). Conclusion: Asymmetry ratio of single support time was statistically significant by static pelvic inclination level. But asymmetry ratio or group II was the highest among three groups. It means that the patients or normal range of pelvic inclination was showed the most asymmetry or gait. And swing time asymmetry ratio was not significant among three groups. Even if the patient has normal ranged static pelvic inclination, it doesn't suggest that the patient has low gait asymmetry.

• Journal of the Korean Society of Physical Medicine
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• v.2 no.2
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• pp.161-171
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• 2007

Purpose : The purpose of this study was to evaluate the effect of footwear on gait in older adults. Methods : The footwear consists of loafer with fixation and mule and slipper without fixation. Twenty one female older adults voluntarily participated in this study. Each participant walked on the gait system GAITRite and measured temporal-spatial gait parameters. And the participants wore loafer, mule, slipper randomly. We measured stance time, swing time, heel-to-heel BOS, double support time, velocity, cadence, FAP as temporal-spatial gait parameters. Results : Three gait parameters showed significant difference statistically among 7 gait parameters. The stance time increased as loafer, mule, barefoot, slipper orderly. And there was a significant difference statistically (p<.05). The swing time increased as slipper, barefoot, mule, loafer orderly. And there was a significant difference statistically(p<.05). And the heel-to-heel BOS increased as barefoot, loafer, mule, slipper orderly. And there was a significant difference statistically(p<.05) according to footwear type. Conclusion : The footwear type with high stability like loafer is considered better than footwear type with low stability like mule and slipper for the elderly.

• Journal of Sensor Science and Technology
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• v.31 no.1
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• pp.41-44
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• 2022

In this study, we have fabricated and characterized vertical double-gate (DG) InGaAs tunnel field-effect-transistors (TFETs) with Al₂O₃/HfO₂ = 1/5 nm bi-layer gate dielectric by employing a top-down approach. The device exhibited excellent characteristics including a minimum subthreshold swing of 60 mV/decade, a maximum transconductance of 141 µS/㎛, and an on/off current ratio of over 10³ at 20℃. Although the TFETs were fabricated using a dry etch-based top-down approach, the values of DIBL and hysteresis were as low as 40 mV/V and below 10 mV, respectively. By evaluating the effects of constant voltage and hot carrier injection stress on the vertical DG InGaAs TFET, we have identified the dominant charge trapping mechanism in TFETs.

• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.900-906
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• 2024

The Passively-Cooled Molten Salt Fast Reactor (PMFR) is one of the advanced design concepts of the Molten Salt Fast Reactor (MSFR) which utilizes a natural circulation for the primary loop and aims to attain a long-life operation without any means of fuel reprocessing. For an extended operation period, it is necessary to have enough fissile material, i.e., high excess reactivity, at the onset of operation. Since the PMFR is based on a fast neutron spectrum, direct implementation of a burnable absorber concept for the control of excess reactivity would be ineffective. Therefore, a localized moderator concept that encircles the active core has been envisioned for the PMFR which enables the effective utilization of a burnable absorber to achieve low reactivity swing and long-life operation. The modified PMFR design that incorporates a moderator and burnable absorber is presented, where depletion calculation is performed to estimate the reactor lifetime and reactivity swing to assess the feasibility of the proposed design. All the presented neutronic analysis has been conducted based on the Monte Carlo Serpent2 code with ENDF/B-VII.1 library.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.168-168
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• 2006

Low-operating voltage organic field-effect transistors (OFETs) have been realized with high dielectric constant (${\kappa}$) polymer such as cyanoethylated poly vinyl alcohol (CR-V, ${\kappa}=12$). Since the $high-{\kappa}$polymers are likely to contain water and ionic impurities, large hysteresis and considerable leakage current are frequently observed in OFETs. To solve these problems, we cross-linked the CR-V by using a cross-linking agent. Cross-linked CR-V dielectrics showed high dielectric constant of 11.1 and good insulating properties, resulting in a high capacitance ($81nF/cm^{2}$ at 1MHz) at 120 nm of dielectric thickness. Pentacene FETs with cross-linked CR-V dielectrics exhibited high carrier mobility ($0.72\;cm^{2}/Vs$), small subthreshold swing (185 mV/dec) and little hysteresis at low-operating voltage (${\Leq}-3V$).

• ETRI Journal
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• v.30 no.4
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• pp.612-614
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• 2008

A novel linear switched termination active cross-coupled low-voltage differential signaling (LVDS) transceiver operating at 1.5 GHz clock frequency is presented. On the transmitter side, an active cross-coupled linear output driver and a switched termination scheme are applied to achieve high speed with low current. On the receiver side, a shared pre-amplifier scheme is employed to reduce power consumption. The proposed LVDS transceiver implemented in an 80 nm CMOS process is successfully demonstrated to provide a data rate of 6 Gbps/pin, an output data window of 147 ps peak-to-peak, and a data swing of 196 mV. The power consumption is measured to be 4.2 mW/pin at 1.2 V.

• The Journal of Korean Physical Therapy
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• v.21 no.2
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• pp.79-85
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• 2009

Purpose: This study examined the characteristics of gait in patients with chronic low back pain. Methods: The subjects were out-patients suffering from chronic low back pain at the department of physical therapy, B hospital in Seoul. Gait analysis was performed by dividing the subjects into two groups. The study and control group comprised 15 chronic low back pain patients and 14 healthy people, respectively. Gait analysis was performed using a VICON 512 Motion Analysis System to obtain the spatio-temporal and kinematic parameters. Results: First, there was a significant difference in the spatio-temporal parameters between the two groups (p<0.05). Second, the study group showed significant differences in the kinematic parameters during the stance phase (p<0.05). Third, there were significant differences in kinematic parameters in the study group during the swing phase (p<0.05). Conclusion: The gait pattern of patients with chronic low back pain is characterized by more rigid patterns. Compared to the control group, there was a decrease in the spatio-temporal parameters and kinematic parameters in patients with chronic low back pain. These findings are expected to play a role as basic data and to form a rehabilitation program for low back pain patients.

• Clean Technology
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• v.17 no.4
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• pp.389-394
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• 2011

A compact adsorption-based process for removal of carbon dioxide and nitrogen from natural gas has been discussed. Among the adsorption-based processes, especially, the pressure swing adsorption (PSA) process has been a suitable unit operation for the purification and separation of gas because of low operation energy and cost. A step cycle is made up of pressurization, feed, equalization, blowdown and rinse. In this work, the PSA process is composed of zeolite 13X and carbon molecular sieve (CMS) for removal of carbon dioxide and nitrogen from mixed gas containing $CH_4/CO_2/N_2$ (75:21:4 vol%). A CMS selectively removes carbon dioxide and a zeolite 13X separates nitrogen from methane. CMS is investigated experimentally due to the high throughput of the faster diffusing component ($CO_2$). The gas composition of top, bottom and feed tank was measured with the gas chromatography (GC) using TCD detector, helium as carrier gas and packed column for analysis of methane, carbon dioxide, and nitrogen.

• Clean Technology
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• v.23 no.2
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• pp.181-187
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• 2017

The perfluorocompounds (PFCs) emitted from the semiconductor and display manufacture is treated by abatement systems which use various technologies, such as combustion, thermal, plasma, catalyst. However, it is required that the system should overcome their drawbacks with excess energy consumption and low removal efficiency. The new technology using combination of pressure swing adsorption and excess enthalpy combustion for the reduction of PFCs emissions were developed and analyzed its characteristics. PFCs concentration ratio and PFCs loss factor were calculated from measuring concentration of PFCs at the calculated by comparing concentration of PFCs at the combustor's inlet and outlet. There were performance evaluations with various gas flow for comparing energy consumption and removal efficiency with existing equipments. The concentration ratio and the loss factor of PFCs were 1.65, 8.2%, respectively, when the total gas flow of the pressure swing absorption (PSA) inlet was 204 liter per minute (LPM) and $CF_4$ concentration was 1412 ppm. In comparison with existing system at constant condition, $CF_4$ removal efficiency for a porous media combustion (PMC) showed the improvement more than 16% and the consumed energy was also reduced up to approximately 41%. Then, the total gas flow introduced into PMC and $CF_4$ concentration were 91-LPM and 2335 ppm, respectively, and the destruction and removal efficiency of $CF_4$ was about 96% at 19-LPM $CH_4$, and 40-LPM $O_2$.