• Journal of the Korean Applied Science and Technology
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• v.33 no.1
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• pp.136-142
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• 2016

The influences of fluorescence, scattering, and flocculation in random media were interpreted for the scattered fluorescence intensity and wavelength, it has been studied the molecular properties by the spectroscopy of laser induced fluorescence(LIF). The effects of optical properties in scattering media have been found by the optical parameters(${\mu}_s$, ${\mu}_a$, ${\mu}_t$). Flocculation is an important step in many solid-liquid separation processes and is widely used in Photodynamic therapy. The interactions of several colloid particles can come into play which have major effect on the flocculation and LIF process. We measured scattering and fluorescence spectra of the sample in vitro as function of distance from lase source to detector. The value of scattering coefficient ${\mu}_s$ is and ${\beta}$-carotene were measured as larger values(I, ${\delta}$) by means of closer distance from source to detector.

• Korean Institute of Interior Design Journal
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• v.24 no.5
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• pp.99-107
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• 2015

The purpose of this study is to analyze the change of visual stimulus of users to the space through the experiment of EEG and the satisfaction of users depends on the lighting. To do that, the results measured with EEG experiment focusing on Beta ${\beta}$ were compared to each other to figure out difference in the changes of the activation of human brain on lighting's situation as the lighting off and on in the same space. The difference in the results was verified according to the characteristic of users which classified with 4 types of the spatial sensitivities. The results of this study are as following. Firstly, the spacial sensitivity of user is to communicate well with the different senses with stimulus through interaction among the elements. At this time, the brain plays a major role in build the spacial sensitivity of users as the place to make form. Secondly, there are the differences in the activation of brain depends on lighting situation even in the same space. The stimulus into the brain became generally stronger in images with lighting on than off. Especially, the response in the occipital lobe which connected with the visual center turn out strongly in the image of 'modern natural'. Because the visual stimulus interact well with the bright color, the reflectional texture and the rough texture painted the dark color. Thirdly, the satisfaction of users changed with lighting in the space. But we could know that the satisfaction of users isn't be related to the visual stimulus through the results of this study. Finally, there isn't the difference in the activation degree of brain according to the characteristic which are preference of users into 4 types of the spatial sensitivity through the results came from ANCOVA(analysis of covariance) with SPSS Program 22.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.6
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• pp.537-545
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• 2009

In this paper, new parameters were developed to estimate the depth of anesthesia during a general anesthesia using EEG. Power spectral density(PSD) analysis was used for these parameters because EEG became slow wave during anesthesia. The new parameters were DTR, ATR, TDR, ADR, BTR and BDR applied to PSD. These parameters were compared with SEF which is conventionally used at clinic and confirmed clinical value. As the results, DTR, ATR, TDR, ADR among parameters were not useful compared with SEF but BTR and BDR is valuable for clinic. 15 patents, at pre-operation BDR the value is $265.36{\pm}25.29$, at induction the value is $129.23{\pm}34.92$, at operation the value is $154.99{\pm}38.34$, at awaked the value is $283.83{\pm}39.80$ and at post-operation the value is $234.80{\pm}23.46$. Also at pre-operation BTR value is $183.38{\pm}13.59$, at induction the value is $104.09{\pm}25.11$, at operation the value is $115.38{\pm}23.42$, at awaked the value is $190.33{\pm}23.31$ and at post-operation the value is $172.38{\pm}19.08$. Trend of BDR and BTR is similar to change of SEF, so two parameters are useful. to estimate the depth of anesthesia.

• New Physics: Sae Mulli
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• v.68 no.12
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• pp.1374-1377
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• 2018

We achieved 95% visibility in the Hong-Ou-Mandel interference experiment while we achieved only 56% visibility in a previous report. We used a 120 mW 405 nm single-mode continuous wave laser, a 5-mm-thick type-1 ${\beta}$-barium borate single crystal, standard Hong-Ou-Mandel interferometer optics, two avalanche photodiode single-photon counters, and a homemade coincidence counting unit. The photon collection unit was the key difference between the present study and the previous study. In the present experiment, we used single-mode optical fibers for photon collection, which suppressed accidental coincidence between-different mode photons by acting as a spatial filter because of its core size being much smaller than a multi-mode fiber.

• Journal of the Korean earth science society
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• v.38 no.1
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• pp.24-34
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• 2017

The westerly waves generation is described in the advanced earth science textbook used at high school as follows: as westerly wind approaches and blows over large mountains, the air flow shows wave motions in downwind side, which can be explained by the conservation of potential vorticity. However, there has been no case study showing the phenomena of the mesoscale westerly waves with observational data in the area of small mountains in Korea. And thus the wind speed and time persistency of westerly winds along with the width and length of mountains have never been studied to explain the generation of the westerly waves. As a first step, we assured the westerly waves generated in the downwind side of Sobaek mountains based on surface station wind data nearby. Furthermore, the critical or minimum wind velocity of the westerly wind over Sobaek mountains to generate the downwind wave were derived and calcuated tobe about $0.6m\;s^{-1}$ for Sobaek mountains, which means that the westerly waves could be generated in most cases of westerly blowing over the mountains. Using surface station data and 4-dimensional assimilation data of RDAPS (Regional Data Assimilation and Prediction System) provided by Korea Meteorological Agency, we also analyzed cases of westerly waves occurrence and life cycle in the downwind side of Sobaek mountains for a year of 2014. The westerly waves occurred in meso-${\beta}$ or -${\gamma}$ scales. The westerly waves generated by the mountains disappeared gradually with wind speed decreasing. The occurrence frequency of the vorticity with meso-${\beta}$ scale got to be higher when the stronger westerly wind blew. When we extended the spatial range of the analysis, phenomena of westerly waves were also observed in the downwind side of Yensan mountains in Northeastern China. Our current work will be a study material to help students understand the atmospheric phenomena perturbed by mountains.

• Journal of Acupuncture Research
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• v.29 no.5
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• pp.1-16
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• 2012

Objectives : The purpose of this study was to examine the effects of manual acupuncture at the $LI_4$, $ST_{36}$ and $LR_3$ on Electroencephalogram(EEG) of patients with stroke. Methods : 32 channel EEG measurement was carried out in 35 Stroke patients(23 males and 12 females). EEG was measured for 21 minutes(made up of 7 sessions, 1 session means 3 minutes time interval) including 15 minutes(5 sessions) of acupuncture time. Power spectrum analysis was used as a measure of complexity. Statistical analysis was performed using Linear mixed model and DUNNETT's multiple comparison. Results : The results were as follows; 1. EEG amplitude was reduced during acupuncture except electrodes PG1 and PG2. 2. There was a notable change during 6~9 minutes after needling in ${\delta}{\cdot}{\beta}{\cdot}{\gamma}$ wave, and during 6~9 minutes after needling in ${\Theta}{\cdot}{\alpha}$ wave. Overall, during 6~9 minutes after needling. 3. TP8 is a common significant electrode among five wave forms. Conclusions : These results suggest that TP8 could be typical electrodes and change of EEG compared to baseline happens most often during 6~9 minutes after manipulated acupuncture at the $LI_4$, $ST_{36}$ and $LR_3$ of patients with stroke.

• Restorative Dentistry and Endodontics
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• v.25 no.3
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• pp.435-445
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• 2000

The purpose of this study was to compare the leakage of four different obturation techniques in conjunction with immediate apical barrier of ${\beta}$-tricalcium phosphate(TCP) in teeth with open apex. Eighty single-rooted human premolar teeth were prepared and sectioned horizontally, so maximum diameter in apex was 4mm. Apical defects that were similar to open apex, were created with #1/2 round bur and SF104R bur. The apical foramen were opened to a size 80 file extended 3mm beyond the apex. The teeth were placed into the oasis block soaked saline to simulate periapical tissue often associated with pulpless teeth and received apical barriers consisting of TCP followed by obturation using lateral condensation technique, vertical condensation technique, continuous wave technique and thermoplasticized gutta-percha injection technique. Two unobturated teeth served as positive and negative controls. Teeth were immersed in resorcinol-formaldehyde resin for S days at $4^{\circ}C$, and the resin was allowed to polymerize completely for 4 days at room temperature. Teeth were then sectioned horizontally at 1.5mm(level 1), 2.5mm(level 2) and 3.5mm(level 3) from the apex, and examined under a stereomicroscope at ${\times}40$ magnification. The photographs were taken at ${\times}40$ magnification of the filling in each level and scanned. The leakage length in tooth/resin interface was measured at each of the three levels. Each ratio of leakage was obtained by calculating the ratio of the leakage length of canal wall infiltrated with resin to the total length of the canal and was analyzed statistically(One-way ANOVA and Scheffe test). The result were as follows : 1. At the level 1, there was the least leakage in the thermoplasticized gutta-percha injection technique group(group 4), but there was statistically significant(p<0.05). 2. At the level 2, there was the least leakage in the thermoplasticized gutta-percha injection technique group(group 4), and the most leakage in the continuous wave technique group(group 3). There was statistically significant difference between the thermoplasticized gutta-percha injection technique group and the continuous wave technique group(p<0.05). 3. At the level 3, there was the least leakage in the thermoplasticized gutta-percha injection technique group(group 4), but there were no statistically significant differences between other groups(p>0.05). These results suggest that thermoplasticized gutta-percha injection technique which had 1mm apical gutta-percha matrix after the formation of TCP apical barrier, can demonstrate favorable apical sealing.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.127-132
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• 2019

This study examined the change in the attention of University students after being given Transcranial Direct Current Stimulation (tDCS). The participants were divided randomly into two group (tDCS vs. Control). tDCS was applied to 37 university students ($23.08{\pm}3.33years$). The tDCS group was applied 2 mA, for 13 minutes twice over a 26 minute period ($n_1=19$). The control ($n_2=18$) was not applied after padding and was applied twice for 13 minutes over a 26 minute period. This study was conducted from September 3 to 28, 2018 and three times a week for a total of four weeks. The electroencephalogram was confirmed to affect attention. tDCS showed significant improvement in the results in the sensory motor rhythm wave (p<0.01, 95% CI: -1.955, -0.459), middle beta wave (p<0.05; 95% CI: 0.027, 0.943), and power ratio (p<0.01, 95% CI: -1.764, -0.315). The results showed that tDCS application increased the attention ability significantly. These results can be applied to attention deficit disorder (ADHD) patients and college students.

• Journal of Biomedical Engineering Research
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• v.19 no.1
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• pp.81-90
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• 1998

Electromagnetic waves may induce various effects on nervous tissues either by thermal or non-thermal mechanisms. This paper intoduces a method to evalute the non-thermal effect to central nervous system by measuring the EEGs of the rabbits treated by nimodipine before exposed to weak microwave field. 20 rabbits were divided into 2 groups and their EEGs were measured after their head section were exposed to 2,450 MHz microwave with the power density of 10 dBm and 20 dBm respectively for 10 minutes and compared with those of the 3rd group of 10 rabbits which were not exposed. The 4th group of 10 rabbits were intravenously given with nimodipine before exposed to 20 dBm field to determine whether this drug would reverse the EEGs changes induced by weak microwave irradiation. As field poser exceeded 20 dBm although no significant physiological changes were observed, total induced EEGs power was remarkably decreased suggesting the presence of CNS activation. Using Fourier analysis on the EEGs signal it was found that remarkable decrease in delta band and increase in the alpha and beta bands in a significant manner(P<0.05) compared to control group. The changes were, however, not reversed by nimodipine-treatment. The effects may be pure thermal in nature because no significant change has been observed in nimodipine treated rabbits.

• 한국해양학회지
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• v.30 no.6
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• pp.565-583
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• 1995

We have used a nonlinear quasi-geostrophic model to study effects of lateral friction and bottom topography on the motion of warm eddies. The two empirical orthogonal functions of the stream function, accounting for the vertical structure, represent the barotropic and first baroclinic dynamic modes. This model is integrated 360 days on a 1000 km ${\times}$ 1000 km domain with a resolution of 10 km ${\times}$ 10 km including both the thermocline and idealized topography of the East Sea. Prescribed inflow through the Korea Strait is compensated by outflow through the Tsugaru Strait. The balance between the nonlinear advection term and the planetary ${\beta}$-effect tends to make northward movement of warm eddy over a flat bottom. The motion of a warm eddy over a sloping topography can be dominated by the nonlinear advection, while nonlinearity plays a secondary role over a flat topography. For eddies dispersing over topography, the nonlinear tendency is a function of time. For a strong warm eddy, northward propagation can occur. For intermediate strength of eddies one might expect a balance between the nonlinear term and the topographic ${\beta}$-effect. As nonlinearity decreases with eddy dispersion, southward motion along the slope may occur by such as a topographic Rossby wave. Our numerical simulations have confirmed the importance of lateral friction on eddy motions, in such a way that the northward penetration of the warm eddy increases drastically by the decrease of the lateral friction. The northward motion of warm eddy can be prevented by reducing the Reynolds number sufficiently. We have also demonstrated the crucial role of topographic effects in the eddy motion process.