• Journal of the Korean Magnetics Society
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• v.15 no.1
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• pp.17-20
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• 2005

The influence of $O_2$ partial pressure on saturation mgnetization, coercivity, anisotropy field and effective permeability (over 1GHz) of as-deposited Co-Fe-Al-O thin films, which were fabricated by RF magnetron reactive sputtering method, were investigated. The $Co_{69.9}Fe_{20.5}A_{14.4O_{5.2}$ thin film fabricated at $O_2$ partial pressure of 4% exhibits the best magnetic softness with saturation magnetization 4${$pi}$Ms of 18.1 kG, coercivity of 0.82 Oe, anisotropy field ($H_k$) of Oe, and effective permeability (${\mu}_{eff}$) about 1,024 above 1 GHz. the electrical resistivity of Co-Fe-Al-O thin films were increased with increasing $O_2$ partial pressure, the electrical resistivity of $Co_{69.9}Fe_{20.5}A_{14.4O_{5.2}$ thin film with the best soft magnetic properties was 560.7 ${\mu}{\Omega}$am. Therefore, It is assumed that the good soft magnetic properties of $Co_{69.9}Fe_{20.5}A_{14.4O_{5.2}$ thin film results from high electrical resistivity and large anisotropy field.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.4
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• pp.89-95
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• 2013

In this work, the evaluation of swirl nozzle injector performance was conducted by investigating effective area ($A_{eff}$), injection mass ($m_{inj}$), injection rate ($Q_{inj}$), and injection delay ($t_{delay}$) under various test conditions. To achieve these, fuel injection analysis system which was composed of fuel supply system, injection system, and control system was installed. At the same time, the swirl nozzle that had 12 orifice hole with $120^{\circ}$ injection angle was used in this work. It was revealed that the difference of injection mass ($m_{inj}$) between base and swirl nozzle injector increased as the injection pressure ($P_{inj}$) and energizing duration ($t_{eng}$) decreased under the same test conditions. The maximum injection rate ($Q_{inj}$) of swirl nozzle injector was higher than base nozzle injector about 2~5%. The injection performance of swirl nozzle was better than base nozzle at low injection pressure ($P_{inj}$) and short energizing duration ($t_{eng}$) conditions.

• Tribology and Lubricants
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• v.6 no.1
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• pp.36-51
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• 1990

A parametric study of the thermal effects of a half-circumferential grooved journal bearings under aligned and misaligned conditions has been carried out by solving numerically the coupled Reynolds and energy equation system. Five different sets of boundary conditions for the energy equation have been used which include mixing between recirculating oil and inlet oil and a contraction ratio for the cavitation region. The effects of changes of the inlet oil temperature and pressure, the wall temperature and the L/D ratio have also been examined. For the range of parameters found in internal combustion engines, the mixing effectiveness at the groove and the resulting final mixture temperature have been found to be as important as the wall temperature and the heat transfer rate. The variability of the temperature, though, has been shown to smooth out the peaks of both pressure and friction during misaligned condition Distributions of friction and pressure in the oil are also examined which may be useful in attempts to reduce friction without reducing load. Results for an axial grooved bearing are also presentsed for comparision purpose.

• Korean Journal of Food Science and Technology
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• v.27 no.6
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• pp.827-833
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• 1995

Temperature distribution tests for a water cascading horizontal retort utilizing superheated water with overpressure as a heating medium were carried out under three different loading conditions, that is, empty(P-0), half-fully(P-3000) and fully(P-6000) loaded operating conditions. Tank volume and full loading capacity of sterilizer used for this study were about 5,900 liter and 1,140 kg(6000 pouches having 190 g weight each), respectively. Set point condition for sterilization was $122^{\circ}C$, 23 minutes and pressure was maintained in the range of $1.8{\sim}2.0\;kg/cm^2$ during sterilization. For each experiment, time-temperature data and F values were obtained from temperature microprocessor($F_0$ monitor). There were significant variations in the temperature distribution at different positions in the sterilizer. The temperature distribution was also affected by the pouch loading condition significantly. The application of the temperature distribution test to a product (retort pouched curry sauce) was conducted at the fully(P-6000) loading condition. Although heat transfer parameters($f_h\;and\;f_c$), and F values were varied with the position of sterilizer, sensory evaluation showed that the temperature distribution of the sterilizer used in this study didn't affect the quality of retorted curry sauce.

• The Journal of Korean Medicine
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• v.30 no.3
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• pp.98-105
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• 2009

Objective: Increased aortic and carotid arterial augmentation index (AI) is associated with the risk of cardiovascular disease. The most widely used approach for determining central arterial AI is by calculating the aortic pressure waveform from radial arterial waveforms using a transfer function. But how the change of waveform by applied pressure and the pattern of the change rely on subject's characteristics has not been recognized. In this study, we use a new method for measuring radial waveform and observe the change of waveform and the deviation of radial AI in the same position by applied pressure. Method: Forty-six non-patient volunteers (31 men and 15 women, age range 21-58 years) were enrolled for this study. Informed consent in a form approved by the institutional review board was obtained in all subjects. Blood pressure was measured on the left upper arm using an oscillometric method, radial pressure waves were recorded with the use of an improved automated tonometry device. DMP-3000(DAEYOMEDI Co., Ltd. Ansan, Korea) has robotics mechanism to scan and trace automatically. For each subject, we performed the procedure 5 times for each applied pressure level. We could thus obtain 5 different radial pulse waveforms for the same person's same position at different applied pressures. All these processes were repeated twice for test reproducibility. Result: Aortic AI, peripheral AI and radial AI were higher in women than in men (P<0.01), radial AI strongly correlated with aortic AI, and radial AI was consistently approximately 39% higher than aortic AI. Relationship between representative radial AI of DMP-3000 and peripheral AI of SphygmoCor had strongly correlation. And there were three patterns in change of pulse waveform. Conclusion: In this study, it is revealed the new device was sufficient to measure how radial AI and radial waveform from the same person at the same time change under applied pressure and it had inverse-proportion to applied pressure.

• Korean Journal of Food Science and Technology
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• v.28 no.1
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• pp.105-108
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• 1996

Microbial and sensory changes during storage at $4^{\circ}C$ of Angelica keiskei juice pressurized at $5700\;kg_f/cm^2$ for 7 min, an optimum process condition suggested from the previous study, were investigated. Pseudomonas, which is responsible for putrefaction of refrigerated food, was totally inactivated by pressurization. E. coli and coliform bacteria were also completely inactivated. According to the sensory evaluation data, high hydrostatic pressure does not change sensory characteristics of freshness, sweetness and bitterness (P<0.05). However, after 8 day storage at $4^{\circ}C$, pressurized Angelica keiskei juice showed higher freshness than untreated control. These results indicated that the high hydrostatic pressure can be used as an effective process method for preserving Angelica keiskei juice.

• Journal of The Korean Society of Clinical Toxicology
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• v.21 no.2
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• pp.117-127
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• 2023

Purpose: No consensus currently exists regarding the maximal pressure of hyperbaric oxygen (HBO₂) therapy performed within 24 hours of acute carbon monoxide (CO) poisoning. This study aimed to evaluate the difference in therapeutic effects according to the first HBO₂ pressure (3.0 atmospheres absolute [ATA] vs. 2.8 ATA). Methods: We used prospectively collected registry data on CO poisoning at a tertiary academic hospital in the Republic of Korea. Adult patients with acute CO poisoning treated with HBO₂ within 24 hours after arrival at the emergency department and without the use of additional HBO₂ after 24 hours between January 2007 and February 2022 were included. Data from 595 patients were analyzed using propensity score matching (PSM). Patients with mild (non-intubated) and severe (intubated) poisoning were also compared. Neurocognitive outcomes at 1 month after CO poisoning were evaluated using the Global Deterioration Scale combined with neurological impairment. Results: After PSM, the neurocognitive outcomes at 1-month post-CO exposure were not significantly different between the 2.8 ATA (110 patients) and 3.0 ATA (55 patients) groups (p=1.000). Similarly, there was also no significant difference in outcomes in a subgroup analysis according to poisoning severity in matched patients (165 patients) (mild [non-intubated]: p=0.053; severe [intubated]: p=1.000). Conclusion: Neurocognitive sequelae at 1 month were not significantly different between HBO₂ therapy pressures of 2.8 ATA and 3.0 ATA in patients with acute CO poisoning. In addition, the 1-month neurocognitive sequelae did not differ significantly between intubated and non-intubated patients.

• Molecular & Cellular Toxicology
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• v.1 no.2
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• pp.116-123
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• 2005

The application of high pressure on cellular morphology, proliferation and protein expression of Jurkat cells (human T lymphocyte cell line) has been extensively investigated. In the present study, we manufactured a novel pressure chamber that modulates 5% $CO_{2}$, temperature and pressure (up to 3 ATA). Jurkat cells was incubated 2 ATA pressure and analyzed cellular morphology and growth using an electron microscopy and MTT assay. The cells showed the morphological changes in the cell surface, which appeared to cause a severe damage in cell membrane. The growth rate of the cells under 2 ATA pressure decreased as cultured time got increased. Furthermore, a long term exposure of high pressure on Jurkat cells may act as one of the important cellular stresses that leads to inducing cell death. Cellular proteomes were separated by 2-dimensional electrophoresis with pH 3-10 ranges of IPG Dry strips. And many proteins showed significant up-and-down expressions with hyperbaric pressure. Out of all, 10 spots were identified significantly using matrix-assisted laser desorption/ionization-time of fight (MALDI-TOF) mass spectrometry. We and found that 9 protein expressions were decreased and one protein, heat shock protein HSP 60, was increased in Jurkat cells under 2 ATA. Identified proteins were related to lipid metabolism and signal transduction.

• Journal of the Korean Society of Physical Medicine
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• v.12 no.3
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• pp.79-84
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• 2017

PURPOSE: The purpose of this study is to examine how task-oriented training focused on lower extremity strengthening can affect mobility function and postural stability. METHODS: The study's subjects included 10 children with cerebral palsy: 7 girls and 3 boys between the ages of 4 and 9 whose Gross Motor Functional Classification System (GMFCS) level was I or II. Their functional mobility was gauged using the Gross Motor Function Measurement (GMFM), and their postural stability was evaluated using a force platform. Participants received task-oriented training focused on lower extremity strengthening for 5 weeks. The study used a paired t-test to investigate the difference in mobility function and postural stability of children with cerebral palsy before and after the lower extremity strengthening exercise. RESULTS: The GMFM dimensions D (standing) (p<.02) and E (walking) (p<.001) improved significantly between the pre-test and post-test. A significant increase in the posturographic center of pressure (CoP) shift and surface area of the CoP were found overall between the pre-test and post-test (p<.001). CONCLUSION: The present study provides evidence that an 8-week task-oriented training focused on strengthening the lower extremities is an effective and feasible strategy for improving the mobility function and postural stability of children with cerebral palsy.

• Physical Therapy Korea
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• v.27 no.2
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• pp.126-132
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• 2020

Background: Augmented somatosensory feedback stimulates the mechanoreceptor to deliver information on bodily position, improving the postural control. The various types of such feedback include ankle-foot orthoses (AFOs) and vibration. The optimal feedback to mitigate postural sway remains unclear, as does the effect of augmented somatosensory feedback on muscle co-contraction. Objects: We compared postural sway and ankle muscle co-contraction without feedback (control) and with either of two forms of somatosensory feedback (AFOs and vibration). Methods: We recruited 15 healthy subjects and tested them under three feedback conditions (control, AFOs, vibration) with two sensory conditions (eyes open, or eyes closed and the head tilted back), in random order. Postural sway was measured using a force platform; the mean sway area of the 95% confidence ellipse (AREA) and the mean velocity of the center-of-pressure displacement (VEL) were assessed. Co-contraction of the tibialis anterior and gastrocnemius muscles was measured using electromyography and converted into a co-contraction index (CI). Results: We found significant main effects of the three feedback states on postural sway (AREA, VEL) and the CI. The two sensory conditions exerted significant main effects on postural sway (AREA and VEL). AFOs reduced postural sway to a level significantly lower than that of the control (p = 0.014, p < 0.001) or that afforded by vibration (p = 0.024, p < 0.001). In terms of CI amelioration, the AFOs condition was significantly better than the control (p = 0.004). Vibration did not significantly improve either postural sway or the CI compared to the control condition. There was no significant interaction effect between the three feedback conditions and the two sensory conditions. Conclusion: Lower-extremity devices such as AFOs enhance somatosensory perception, improving postural control and decreasing the CI during static standing.