• Title, Summary, Keyword: TMS

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Power Quality Measurement for LED-based Green Energy Lighting Systems (LED 기반 그린에너지 조명시스템을 위한 전력품질 측정)

  • Yu, Hyung-Mo;Choi, Jin-Won;Choe, Sangho
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.2
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    • pp.174-184
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    • 2013
  • For the successful R&D and deployment of LED-based green energy lighting systems, the real-time power quality measurement of both various non-linear power signals including pulse waveform, spike waveform, etc and the undesired-signals including harmonics, sag, swell, etc is required. In this paper, we propose a low-cost power quality measurement (PQM) method for low- (60Hz-several KHz) to high-frequency (several tens KHz) power signals, which are generated by green-energy lighting systems, and implement a PQM testbed using TI TMS320F28335 MCU. The proposed algorithm is programmed using C in the CCS (Code Composer Studio) 3.3 environment and is verified using test signals generated by an arbitrary signal generator, NF-WF1974. In the implemented testbed, we can measure various non-linear current signals that LED SMPS generates, analyze harmonics by fast Fourier transform, and test sag, swell, and interruption using wavelet transform.

Determination of plasma ketone body following oximation-trimethylsily| derivatization using gas chromatography-mass spectrometry selected ion monitoring (혈장 중 케톤체의 옥심-TMS 유도체화 후 GC-MS/SIM을 이용한 분석)

  • Yoon, Hye-Ran
    • Analytical Science and Technology
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    • v.29 no.1
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    • pp.49-55
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    • 2016
  • A ketone body (acetoacetic acid, β-hydroxybutyric acid, and acetone) increases from blood or urine when bio-energy dependence pays more fatty acid than glucose. However, in case oxidation of fat is greater than the capacity of the citric acid cycle the fatty acid oxidation is made from acetoacetyl CoA to acetoacetate then, again form β-hydroxyburytic acid to acetone, the diffusion take place into the blood. Enzymes that oxidize ketone body in the brain and nerve tissue blood ketone dody is increased during prolonged fasting, brain used it as energy. In this study, we developed the rapid two step derivatization method for sensitive detection of the ketone body by GC-MS/SIM. The plasma was deproteinized and then the hydroxy and carboxyl groups of ketone body are subjected to extraction and drying then, keto-group were derivatized with hydoxylamine at 60℃ for 30 min for oximation. Then it was trimetyl-silylated with BSTFA at 80℃ for 30 min and analyzed using a GC-MS. The linear ranges were in between 0.001 μg/mL and 250 μg/mL for β-hydroxy butyrate, and acetoacetate. The method detection limits were below 0.1 pg over each target compound determined. The mean recoveries (%) of target compounds were ranged from 88.2 % to 92.3 % at 1 µg/mL, from 89.5 % to 94.8 % at 10 μg/mL, with RSD of 6.3-9.4 %. This method could be applied to quantification of ketone bodies which are seen in the keto-acidosis in children and adults from a variety of diseases that cause ketones in the blood and urine.

Effect of Coagulants on the Behavior of Ultra Fine Dust in a Coal Firing Boiler (석탄 화력 보일러에서의 응집제 이용에 따른 초미세먼지 거동)

  • Ryu, Hwanwoo;Song, Byungho
    • Applied Chemistry for Engineering
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    • v.31 no.1
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    • pp.84-89
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    • 2020
  • Particulate matters of PM2.5, particularly focusing on 0.1~1 ㎛ decrease the efficiency of dust-collector due to the brownian-motion. This study is to verify the effect of coagulant on the particle size distributions of potassium and PM2.5. The activated coagulant was spayed to the coal fired fluidized bed combustion boiler by the weight ratio of 1,200 : 1 = coal : coagulant, and the size distributions of captured particles at both the cyclone (FP) and electrostatic precipitator (EP) were measured. As the result of XRP analysis, the potassium content of FP increased to 13.33% (averagely from 1.65% to 1.87%) and, in EP at 17.68% (averagely from 1.65% to 2.03%). And it was confirmed by the particle size distribution analyzer and SEM image analysis that the distribution rates of PM2.5 decreased at 89.53% on average in FP, and at 88.57% in EP. The total dust concentration (mg/㎥) confirmed by tele-monitering system (TMS) decreased during the primary test from 2.6 to 1.7~1.9 and also the secondary test from 2.9 to 1.7~1.9.

A Study on Transcranial Magnetic Electrode Simulation Using Maxwell 3D (Maxwell 3D를 이용한 경두개 자기 전극 시뮬레이션에 관한 연구)

  • Lee, Geun-Yong;Yoon, Se-Jin;Jeong, Jin-hyoung;Kim, Jun-Tae;Lee, Sang-sik
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.12 no.6
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    • pp.657-665
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    • 2019
  • In this study, we conducted a study on the transcranial magnetic electrode, a method for the study of dementia and muscle pain, a neurodegenerative disease caused by an aging society, which is becoming a problem worldwide. In particular, transcranial magnetic electrodes have been studied to improve their ability to be deteriorated by dementia symptoms such as speech, cognitive ability, and memory by outputting magnetism deep into the brain using coils on the head epidermis. In this study, simulation was performed using Maxwell 3D program for the design of coil, the core of transcranial magnetic electrode. As a result of the simulation comparison between the coil designed by the previous research and the coil through the research and development, the output was found to be superior to the conventional designed coil. The graphs of the coil outputs of B-Field and H-Field are found to be symmetrical, but the symmetry between each coil is pseudo-symmetrical and not accurate. Based on these results, an experiment was conducted to confirm whether the output of the head epidermis through both coils is possible. In the magnitude field of the reverse-coil 2-coil analysis, the maximum output was 3.3920e + 004 H [A_per_meter], and the vector field showed the strongest magnetic field around 35 to 165 degrees. It was confirmed that the magnetic output canceled due to the magnetic output. In the case of the forward 2-coil, a maximum of 3.2348e + 004H [A_per_meter] similar to the reverse coil was observed, but in the case of the vector field, the magnetic output regarding the forward output and the head skin output was confirmed. However, when the height change in the output coil, the magnetic output was reduced.

Optimization of Analytical Methods for Octacosanol in Related Health-functional Foods with GC-MS (GC-MS를 이용한 건강기능식품 중 옥타코사놀 분석법 개발 연구)

  • Lee, Jin Hee;Oh, Mi Hyune;Lee, Kyung Jin;Kim, Yang Sun;Keum, Eun Hee;Park, Ji Eun;Cho, Mee Hyun;Seong, Min Hye;Kim, Sang A;Kim, Mee hye
    • Journal of Food Hygiene and Safety
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    • v.33 no.4
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    • pp.266-271
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    • 2018
  • The Ministry of Food and Drug Safety (MFDS) is amending its test methods for health-functional foods (dietary food supplements) to establish regulatory standards and specifications in Korea. In this regard, we continue our research on developing analytical methods for the items. Octacosanol is the major component of polycosanol and is a high-molecular-mass primary fatty alcohol, obtained from sugar cane wax. Previous researchers have shown that octacosanol can lower cholesterol and has antiaggregatory properties, cytoprotective uses, and ergogenic properties for human health. Recently, octacosanol products have been actively introduced into the domestic market because of their functional biological activity. We have developed a sensitive and selective test method for octacosanol that the TMS derivatives by means of gas-chromatographic-tandem mass spectrometry (GC-MS). The trimethylsilyl ether derivative of the target analyte showed excellent chromatographic properties. The procedure was validated in the range of $12.5{\sim}200{\mu}g/L$. Standard calibration curves presented linearity with the correlation coefficient ($r^2$) > 0.999, and the limits of detection (LOD) and limits of quantitation (LOQ) were $4.5{\mu}g/L$ and $13.8{\mu}g/L$, respectively. The high recoveries (92.5 to 108.8%) and precision (1.8 to 2.4%) obtained are in accordance with the established validation criteria. Our research can provide scientific evidence to amend the octacosanol test method for the Health-Functional Food Code.

Effects of electromagnetic stimulation on neurogenesis and neuronal proliferation in rat hippocampal slice culture (실험 쥐 해마조직배양에서 전자기 자극이 신경조직발생 및 증식에 미치는 영향)

  • Kim, Deok-Soo;Choi, Eung Sang;Chae, Soo Ahn
    • Clinical and Experimental Pediatrics
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    • v.49 no.5
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    • pp.558-564
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    • 2006
  • Purpose : Transcranial electromagnetic stimulation(TMS) is a noninvasive method which stimulates the central nervous system through pulsed magnetic fields without direct effect on the neurons. Although the neurobiologic mechanisms of magnetic stimulation are unknown, the effects on the brain are variable according to the diverse stimulation protocols. This study aims to observe the effect of the magnetic stimulation with two different stimulation methods on the cultured hippocampal slices. Methods : We obtained brains from 8-days-old Spague-Dawley rats and dissected the hippocampal tissue under the microscope. Then we chopped the tissue into 450 µm thickness slices and cultured the hippocampal tissue by Stoppini's method. We divided the inserts, which contained five healthy cultured hippocampal slices respectively, into magnetic stimulation groups and a control group. To compare the different effects according to the frequency of magnetic stimulation, stimulation was done every three days from five days in vitro at 0.67 Hz in the low stimulation group and at 50 Hz in the high stimulation group. After N-methyl-D-aspartate exposure to the hippocampal slices at 14 days in vitro, magnetic stimulation was done every three days in one and was not done in another group. To evaluate the neuronal activity after magnetic stimulation, the $NeuN/{\beta}$-actin ratio was calculated after western blotting in each group. Results : The expression of NeuN in the magnetic stimulation group was stronger than that of the control group, especially in the high frequency stimulation group. After N-methyl-D-aspartate exposure to hippocampal slices, the expression of NeuN in the magnetic stimulation group was similar to that of the control group, whereas the expression in the magnetic non-stimulation group was lower than that of the control group. Conclusion : We suggest that magnetic stimulation increases the neuronal activity in cultured hippocamal slices, in proportion to the stimulating frequency, and has a neuroprotective effect on neuronal damage.

Brazing characteristics of $ZrO_2$ and Ti-6Al-4V brazed joints with increasing temperature (브레이징 온도 변화에 따른 $ZrO_2$와 Ti-6Al-4V의 접합 특성)

  • Kee, Se-Ho;Park, Sang-Yoon;Heo, Young-Ku;Jung, Jae-Pil;Kim, Won-Joong
    • The Journal of Korean Academy of Prosthodontics
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    • v.50 no.3
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    • pp.169-175
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    • 2012
  • Purpose: In this study, brazing characteristics of $ZrO_2$ and Ti-6Al-4V brazed joints with increasing temperature were investigated. Materials and methods: The sample size of the $ZrO_2$ was $3mm{\times}3mm{\times}3mm$ (thickness), and Ti-6Al-4V was $10mm(diameter){\times}5mm(thickness)$. The filler metal consisted of Ag-Cu-Sn-Ti was prepared in powder form. The brazing sample was heated in a vacuum furnace under $5{\times}10^{-6}$ torr atmosphere, while the brazing temperature was changed from 700 to $800^{\circ}C$ for 30 min. Results: The experimental results shows that brazed joint of $ZrO_2$ and Ti-6Al-4V occurred at $700-800^{\circ}C$. Brazed joint consisted of Ag-rich matrix and Cu-rich phase. A Cu-Ti intermetallic compounds and a Ti-Sn-Cu-Ag alloy were produced along the Ti-6Al-4V bonded interface. Thickness of the reacted layer along the Ti-6Al-4V bonded interface was increased with brazing temperature. Defect ratios of $ZrO_2$ and Ti-6Al-4V bonded interfaces decreased with brazing temperature. Conclusion: Thickness and defect ratio of brazed joints were decreased with increasing temperature. Zirconia was not wetting with filler metal, because the reaction between $ZrO_2$ and Ti did not occur enough.

Statistically Analyzed Effects of Coal-Fired Power Plants in West Coast on the Surface Air Pollutants over Seoul Metropolitan Area (통계적 기법을 활용한 서해안 화력발전소 오염물질 배출에 따른 수도권 지표면 대기오염농도 영향의 분석)

  • Ju, Jaemin;Youn, Daeok
    • Journal of the Korean earth science society
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    • v.40 no.6
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    • pp.549-560
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    • 2019
  • The effects of the coal-fired power plant emissions, as the biggest point source of air pollutants, on spatiotemporal surface air pollution over the remote area are investigated in this study, based on a set of date selection and statistical technique to consider meteorological and geographical effects in the emission-concentration (source-receptor) relationship. We here proposed the sophisticated technique of data processing to separate and quantify the effects. The data technique comprises a set of data selection and statistical analysis procedure that include data selection criteria depending on meteorological conditions and statistical methods such as Kolmogorov-Zurbenko filter (K-Z filter) and empirical orthogonal function (EOF) analysis. The data selection procedure is important for filtering measurement data to consider the meteorological and geographical effects on the emission-concentration relationship. Together with meteorological data from the new high resolution ECMWF reanalysis 5 (ERA5) and the Korea Meteorological Administration automated surface observing system, air pollutant emission data from the telemonitoring system (TMS) of Dangjin and Taean power plants as well as spatio-temporal air pollutant concentrations from the air quality monitoring system are used for 4 years period of 2014-2017. Since all the data used in this study have the temporal resolution of 1 hour, the first EOF mode of spatio-temporal changes in air pollutant concentrations over the Seoul metropolitan area (SMA) due to power plant emission have been analyzed to explain over 97% of total variability under favorable meteorological conditions. It is concluded that SO2, NO2, and PM10 concentrations over the SMA would be decreased by 0.468, 1.050 ppb, and 2.045 ㎍ m-3 respectively if SO2, NO2, and TSP emissions from Dangjin power plant were reduced by 10%. In the same way, the 10% emission reduction in Taean power plant emissions would cause SO2, NO2, and PM10 decreased by 0.284, 0.842 ppb, and 1.230 ㎍ m-3 over the SMA respectively. Emissions from Dangjin power plant affect air pollution over the SMA in higher amount, but with lower R value, than those of Taean under the same meteorological condition.