• Proceedings of the Materials Research Society of Korea Conference
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• 1994.11a
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• pp.1-1
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• 1994

;The electronic state calculations for various types of ceramic materials have beell performed by the use of $DV-X\;{\alpha}$ cluster method. The molecular orbital levels and wave functions for model clusters have been computed to study the electronic properties ami chemical bonding of the ceramics. For ${\beta}-sialon(Si_{6-z}Al_zO_zN_{8-z})$ which is a high temperature structural material based on ${\beta}-Si_3N_4$, we have made model cluster calculations to estimate the strength of chemical bonding between atoms by the Mulliken population analysis. It is found that the covalent bonding between Si and N atoms is very strong in pure ${\beta}-Si_3N_4$, but the covalency around solute atom is considerably weakened when Si atom is substituted by AI. This tendency is enhanced by an additional substitution of oxygen atom for N. The result calculated can well explain the experimental data of changes in mechanical properties such as the reductions of Young's modulus and Vickers hardness with increment of z-value in ${\beta}-sialon$. Various model clusters for transition metal oxides which show many interesting physical and chemical properties have also been calculated. High-valent perovskite-type iron oxides EMFe0_3E(M=Ca and Sr) possess very interesting magnetic and chemical properties. In these oxides, iron exists as $Fe^{4+}$ state, but the experimental measurement of Mossba~er effect suggests that disproportionation $2Fe^{4+}=Fe^{3+}+Fe^{5+}$ takes place for $CaFe0_3$ at low temperatures. The model cluster calculations for these compounds indicated the existence of considerably strong covalent bonding of Fe-O. The calculations of hyperfine interaction at iron neucleus show very good agreement with the experimental Mossbauer measurements. The result calculated also implies that the disproportionation reaction is strongly possible by assuming the quenching of breathing phonon mode at low temperatures.tures.

• Korean Journal of Acupuncture
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• v.29 no.3
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• pp.467-475
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• 2012

Objectives : The aim of this study was to examine the effects of Acupuncture at the GV20 and GV22 on normal human beings using power spectrum analysis. Methods : Electroencephalogram(EEG) power spectrum exhibits site-specific and state-related differences in various frequency bands. 8 channels Background Electroencephalogram (EEG) was carried out in 30 subjects(24 females and 4 males). Results : In ${\delta}$(theta) band, the power values decreased significantly at the 8-channel average value(p=0.03) and especially at T3(p=0.02), T4(p=0.001) and P3(p=0.03). In ${\alpha}$(alpha) band, the power values have no significant changes. In ${\beta}$(beta)band, the power values increased significantly at the 8-channel average value (p=0.02) and especially at T4(p=0.003), P3 (p= 0.03) and P4(0.02). In ${\beta}/{\delta}$(beta/theta) ratio, the value increased significantly at the 8-channel average value(p=0.002) and especially at Fp2(p=0.05), F4(p=0.007), T3(0.012), T4(0.005), P3 (0.007) and P4(0.03) Conclusions : Through this data, we conclude that acupuncture at the GV20 and GV22 on normal human beings could have possibility to awake the cerebral cortex by the functional mechanism.

• Korean Journal of Optics and Photonics
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• v.5 no.3
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• pp.349-355
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• 1994

Superrsolution of an optical imaging system, which resolves $\epsilon_O$ (half width of the square top amplitude impulse function) less than the Rayleigh's resolution limit $\epsilon_R$, is theoretically treated by using the diffraction theory, and an experimental system is proposed. Initially superresolution is stated as an inverse problem, and an integral equation is derived as a function of parameter $\beta$, which is positive. The integration is numerically carried out for the given aperture and those given values of $\beta$, which is 1, 5, 10, 15, and 20. 1/2$\times$FWHM's of the amplitude impulse functions are meassured for the cases of diffrent value of {J and in the case of $\beta=5$, the half-width already approaches to $\epsilon_O=0.1$,urn, which is, in the case of the present work, one fifth of the Rayleigh's resolution limit. It is found both the pupil function and the phase of the Huygens wave are to be modified, and theories of the pupil function modulation plate and the phase modulation hologram plate are also presented. The result obtained may be useful in ultrafine optical lithography.graphy.

• Applied Biological Chemistry
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• v.19 no.4
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• pp.243-247
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• 1976

A potent intracellular-lipid-producing yeast, Rhodotrorular glutinis var. glutinis sw-17 was studied on the production of carotenoids after shaking the cultures for 8 days at $25^{\circ}C$. The pigments were extracted with solvents and chromatographed with columns for its isolation. The carotonoids were identified by their positions on the column, and by their light-absorption curves. Close agreement was obtained between the absorption maxima of the isolated pigments and published literature values. The characteristic wave length maxima and the extinction values used for quantitative determination. The caroteniod pigments produced by the yeast were composed of torularhodin(28.52%), torulene(38.16%), neurosporene(1.49%), ${\gamma}-carotene(9.88%)$, ${\beta}$-zeacarotene(2.0%), ${\beta}-carotene(19.95%)$ and ${\delta}-carotene(trace)$.

• Journal of Preventive Medicine and Public Health
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• v.52 no.6
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• pp.366-376
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• 2019

Objectives: The relationships among discrimination, social support, and mental health have mostly been studied in minorities, and relevant studies in the general population are lacking. We aimed to investigate associations between discrimination and depressive symptoms in Korean non-minority young adults, considering the role of social support. Methods: In total, 372 participants who completed the psychological examinations conducted in the third wave of the Jangseong High School Cohort study were included. We used the Everyday Discrimination Scale to evaluate perceived discrimination and the Beck Depression Inventory-II to measure depressive symptoms. Social support was measured by the Multidimensional Scale of Perceived Social Support. Multivariate linear regression was conducted to investigate associations between discrimination and depression, along with the effect modification of social support. We stratified the population by gender to investigate gender differences. Results: Perceived discrimination was significantly associated with depressive symptoms (${\beta}=0.736$, p<0.001), and social support was negatively associated with depression (${\beta}=-0.245$, p<0.001). In men, support from friends was the most influential factor (${\beta}=-0.631$, p=0.011), but no significant effect modification was found. In women, support from family was the most influential factor (${\beta}=-0.440$, p=0.010), and women with higher familial support showed a significantly diminished association between discrimination and depression, unlike those with lower family support. Conclusions: Discrimination perceived by individuals can lead to depressive symptoms in Korean young adults, and this relationship can may differ by gender and social support status.

• Journal of the Korea Convergence Society
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• v.9 no.11
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• pp.443-454
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• 2018

The purpose of this convergence study was to evaluate and to identify predictors of health-related quality of life(HRQoL) of families with cancer survivor(FCS) focusing on the comparison of families with cancer patient(FCP) receiving treatments. The research was conducted with the data for 153 FCS and 115 FCP taken from the 6th wave of the Korea National Health and Nutrition Examination Survey. The independent variables included socio-demographic, health related, psychological and social factors. The data were analyzed by hierarchical multiple regression analysis using SPSS/WIN 18.0. The results showed different patterns of predictors on the HRQoL of FCS and FCP. In FCS, the statistically significant factors were stress(${\beta}=-.192$, p<.05) and exclusion from economic activities(${\beta}=-.191$, p<.05). Therefore, families of cancer patients also need appropriate interventions for each stage of the disease.

• Journal of People, Plants, and Environment
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• v.22 no.4
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• pp.355-364
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• 2019

This study was conducted to find out the effects of agro-healing activities and strolling on the physiological conditions of patients with chronic metabolic diseases. A total of 11 subjects participated in agro-healing activities, and their average age was 49.6±11.3. Changes in their salivary cortisol were compared and analyzed before and after participating in the agro-healing activity program, and it was found that the stress hormone decreased after participating in the program. Differences in brain wave between before and after participating in agro-healing activities and strolling were measured, and the ratio of alpha to high beta (RAHB) of subjects increased in most of the measured points after participating in agro-healing activities. In addition, the increase in the value in the temporal lobe (T3) that controls mortor skills and occipital lobe (O2) that controls visual functions indicates that the activities were effective in improving relaxation and stability. The relative low beta (RLB) power spectrum of subjects also statistically significantly decreased in the right occipital lobe (O2) that controls visual functions, the relative mid beta (RMB) and relative high beta (RHB) power spectrum decreased in the left temporal lobe (T3) and the right occipital lobe (O2). These results indicate that the activities were effective in improving relaxation under no stress and tension. The systolic and diastolic blood pressure of subjects after participating in agro-healing activities decreased from the prehypertension level to the normal level. These results indicate that horticultural activities and visual elements in healing farms, such as agro-healing activities and strolling, have positive impacts on patients with chronic metabolic diseases accompanied with diabetes or high blood pressure by increasing the brain activity and psycho-physiological conditions of participants.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.1
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• pp.124-130
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• 2017

This study is aimed to find out whether there is difference in the physiological change of a human body according to the illumination and color of interior space or not and to specify the effect of the condition of illumination and color, respectively on the attention. In order to do so, White and Green were selected for colors and 4,000k, 5,000k, and 6000k were done for color temperature, and then attention was identified. Examining the results, the more color temperature increased, the more attention improved (P < 0.05), and in the case of EEG, ${\alpha}$ wave decreased while performing the task of attention (P < 0.01), and ${\beta}$ wave decreased more in Green than White in color condition, and it increased more in 4,000k than 5,000k and 6,000k (p < 0.05) in color temperature condition. To sum up, color condition didn't contribute to the attention much, in the case of color temperature, when it is 6,000k, it is judged that it helped to improve attention. It is considered that relaxation contributed to improving attention, as ${\beta}$ wave and sympathetic nerve decreased in 6,000k (p < 0.05). It is judged that the relaxation of tensions which happened due to a beta wave and the reduction of sympathetic nervous system activity in 6,000k, a condition of high color temperature, contributed to the improvement of concentration. In further researches, it is intended that a test will be conducted for the subjects of different ages, and the correlation between color temperature and color stimulation and the influence of them on human body would be observed in subdivided, various test conditions through various color temperature and color stimulation.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.5-9
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• 2000

The visual evoked potential was electrophysiological method for the identify of the EEG response on visual cortex. This test was objective test method on the eye function. This study was used the visual evoked potential for the objective color test. The subjects was a normal color function in Korean adults. The test condition was performed on the differens distance and illumination. According to convergence condition of color vision target. On the appearance of EEG wave of visual stimulation on visual cortex. The most EEG wave style was delta wave, and the next amount wave form was beta wave and theta wave, and the least EEG wave form was alpha wave. The histogram of amplitude of EEG wave form was almost non-Gaussian shape, and the phase diagram of amplitude was almost all linear shape. On the kinds of color vision target, the frequency of EEG wave style appeared a similar results.

• Ocean Systems Engineering
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• v.3 no.2
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• pp.149-165
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• 2013

Tension leg platforms (TLP's) are highly nonlinear due to large structural displacements and fluid motion-structure interaction. Therefore, the nonlinear dynamic response of TLP's under hydrodynamic wave loading is necessary to determine their deformations and dynamic characteristics. In this paper, a numerical study using modified Morison Equation was carried out in the time domain to investigate the influence of nonlinearities due to hydrodynamic forces and the coupling effect between all degrees of freedom on the dynamic behavior of a TLP. The stiffness of the TLP was derived from a combination of hydrostatic restoring forces and restoring forces due to cables and the nonlinear equations of motion were solved utilizing Newmark's beta integration scheme. The effect of wave characteristics was considered.