• Current Applied Physics
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• v.18 no.11
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• pp.1196-1200
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• 2018

We have experimentally demonstrated circular polarization generation from linear polarized soft X-ray at synchrotron by adopting a thin magnetic film polarizer. Polarizer is composed of Co/Pt multilayer with a perpendicular magnetic anisotropy, which allows us to easily accommodate without needing any tilting angle into the measurement setup since the circular polarization is generated for the X-ray with normal incidence and transmission. Generated circular polarization is examined by observing magnetic domain features based on the X-ray magnetic circular dichroism, where~11% of circular component is estimated compared to the case of full circular polarization.

• Journal of Magnetics
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• v.11 no.2
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• pp.61-65
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• 2006

The physical origin of complex dynamic domain configuration in nonequilibrium magnetic systems with mesoscopic length scales has been studied. An increasing complexity in the spatial feature of the evolution is found to accompany the increasing reversal speed, when a ferromagnetic element is driven by progressively faster switching fields applied antiparallel to the initial magnetization direction. As reversal rates approach the characteristic precession frequencies of spin fluctuations, the thermal energy can boost the magnetization into local configurations which are completely different from those experienced during quasistatic reversal. The sensitive dependence of the spatial pattern on switching speed can be understood in terms of a dynamic exchange interaction of thermally excited spins; the coherent modulation of the spins is strongly dependent on the rise time of switching pulses.

• Journal of Electrical Engineering and Technology
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• v.6 no.1
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• pp.128-132
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• 2011

In this paper, two automatic mesh generation algorithms are presented. The methods seek to optimize mesh density with regard to geometries exhibiting both fine and coarse physical structures. When generating meshes, the algorithms attempt to satisfy the conditions on the maximum mesh spacing and the maximum grading ratio simultaneously. Both algorithms successfully produce non-uniform meshes that satisfy the requirements for finite-difference time-domain simulations of microwave components. Additionally, an algorithm successfully generates a minimum number of grid points while maintaining the simulation accuracy.

• Proceedings of the Korean Magnestics Society Conference
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• 2017.05a
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• pp.53-54
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• 2017

Direct observation of the DW dynamics in a bifurcated wire reveals that the propagation is via the splitting of DW at the junction, resulting in individual DW in each branch. The DMI induced DW tilting leads to quasi-selective propagation through the network structure, with favored branch determined by the tilting angle of the DW surface. This results in the DW in the individual branches having different depinning fields. Our work shows that by tuning the DMI constant in a material, selective DW motion through a network can be achieved.

• Structural Engineering and Mechanics
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• v.90 no.4
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• pp.429-434
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• 2024

In the current work, the effect of rotation and mechanical force on a nonlocal micropolar thermoelastic solid with temperature-dependent properties was discussed using Erigen's nonlocal thermoelasticity theory. The problem is resolved using Laplace transforms and Fourier series. For the nonlocal and local parameters, the physical fields have been illustrated. The numerical inversion approach is used to acquire the resulting fields in the physical domain. Based on numerical analysis, the effects of rotation, the modulus of elasticity's dependency on temperature, and nonlocal, mechanical force are examined on the physical fields.

• Journal of the Korean Society of Radiology
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• v.15 no.4
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• pp.499-505
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• 2021

In this study, HRV signals are analyzed to compare the autonomic nervous system activity of non-pregnant women and pregnant women. 99 disease-free pregnant women and 27 non-pregnant women from W Hospital participated in the study. The acquired HRV signals were used by the program to perform time domain analysis and frequency domain analysis. The measured values were statistically analyzed for differences between pregnancy periods through a one-way ANOVA. In the results, SDNN and RMSSD in time domain analysis had significantly higher results in early pregnancy and non-pregnant women compared to mid- and late pregnancy. In frequency domain analysis, LF and HF had significantly higher values for pregnancy and non-pregnancy compared to midand late-term, but there was no significant difference between VLF and LF/HF. his means that as pregnancy progresses, the ability to control autonomous nerves decreases in the middle and late stages of pregnancy and increases physical fatigue and mental fatigue. Therefore, the longer the pregnancy period, the more special care is needed to maintain mental and physical stability of pregnant women.

• Physical Therapy Rehabilitation Science
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• v.11 no.2
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• pp.154-164
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• 2022

Objective: The purpose of this study is to select a cognitive training game that can evaluate five cognitive domains and to study their validity with existing cognitive evaluation tools. Design: Methods: Delphi survey was conducted through the 2nd questionnaire for 30 experts to select games suitable for training 5 cognitive domains. Five cognitive training games and Mini Mental State Examination - Korea(MMSE-K), and cognitive impairment screening test(CIST) were conducted for 82 elderly in the community. Pearson correlation analysis was performed to find out the correlation of the three tests. The ROC curve was used to calculate the selection criteria for the game results for the screening evaluation of the presence or absence of mild cognitive impairment. Results: The coefficient of variation to evaluate the stability of the Delphi survey was less than 0.50 in most game items. The 'correct answers' and 'level' of the five final selected game items showed a statistically significant positive correlation with the CIST and MMSE-K scores. CIST score and 'time' of all game items except 'number making_time' showed a statistically significant negative correlation. Conclusions: The validity of the cognitive training program using smart devices was evaluated, and the criteria for classifying the cognitive domain and distinguishing the presence or absence of cognitive impairment were confirmed.

• Journal of Preventive Medicine and Public Health
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• v.44 no.4
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• pp.149-156
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• 2011

Objective: The purpose of the present study was to examine the relationship between the use of senior center and health-related quality of life in Korean older adults. Methods: A questionnaire survey was conducted to two types of older adults who lived in Busan, Korea: 154 older adults who used a senior center and 137 older adults who did not use a senior center. The Korean version of short-form 36-item health survey was administered to assess the health-related quality of life. Demographic variables were obtained from a questionnaire. These were gender, age, family status, marital status, education, monthly income, present illness, body mass index and physical activity. Results: The 8-domain scales of physical function and role-physical were significantly higher in the users of the senior center compared with the non-users (F=4.87, p=0.027 and F=7.02, p=0.009, respectively). The 8-domain scales of vitality was also significantly higher in the users of the senior center compared with the non-users (F=7.48, p=0.007). Conclusions: The present study showed that the users of the senior center have higher physical function, role-physical and vitality compared with the non-users. These findings suggest that although the results are unable to specify causal relationships using the senior center may lead to some improvement in health-related quality of life.

• Nuclear Engineering and Technology
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• v.56 no.2
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• pp.745-752
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• 2024

A method for gamma/neutron event classification based on frequency-domain analysis for mixed radiation environments is proposed. In contrast to the traditional charge comparison method for pulse-shape discrimination, which requires baseline removal and pulse alignment, our method does not need any preprocessing of the digitized data, apart from removing saturated traces in sporadic pile-up scenarios. It also features the identification of neutron events in the detector's full energy range with a single device, from thermal neutrons to fast neutrons, including low-energy pulses, and still provides a superior figure-of-merit for classification. The proposed frequency-domain analysis consists of computing the fast Fourier transform of a triggered trace and integrating it through a simplified version of the transform magnitude components that distinguish the neutron features from those of the gamma photons. Owing to this simplification, the proposed method may be easily ported to a real-time embedded deployment based on Field-Programmable Gate Arrays or Digital Signal Processors. We target an off-the-shelf detector based on a small CLYC (Cs2LiYCl6:Ce) crystal coupled to a silicon photomultiplier with an integrated bias and preamplifier, aiming at lightweight embedded mixed radiation monitors and dosimeter applications.

• Korean Journal of Adult Nursing
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• v.22 no.2
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• pp.211-220
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• 2010

Purpose: This study was done to identify the relationship of trait anger, health state, physical symptoms. and general characteristics to physical symptoms and to identify factors affecting physical symptoms of elderly in urban areas. Methods: The research design for this study was a descriptive survey design using a convenience sampling. Elders (n=276), who agreed to participate in this study completed a self-reporting questionnaire. The collected data were analyzed by descriptive statistics, t-test, ANOVA, Pearson's correlation coefficients, and multiple regression. Results: Study participants reported low trait anger (M=18.61), physical symptoms (M=7.15), and moderate health state (M=3.30). The 45.4%of variance in physical symptoms was significantly explained by emotional function health state (${\beta}$=-.284, p=.013), which is one of the sub-domain of the elderly health state, and trait anger (${\beta}$=3.841, p<.001). Conclusion: Findings of this study provide that the most important factors in explaining physical symptoms for the elders in Korea were emotional function health state and trait anger. Based on the findings of this study, further nursing practice and nursing research for the elders with physical symptoms should be focused on emotional support.