• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.1
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• pp.38-42
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• 2005

B$_2$O$_3$ added Ba(Mg$_{1}$3/Nb$_{2}$3/)O$_3$ (BBMN) ceramics were not sintered below 900 $^{\circ}C$. However, when CuO was added to the BBMN ceramic, it was sintered even at 850 $^{\circ}C$. The amount of the $Ba_2$B$_2$O$_{5}$ second phase decreased with the addition of CuO. Therefore, the CuO additive is considered to react with the B$_2$O$_3$ inhibiting the reaction between B$_2$O$_3$ and BaO. Moreover, it is suggested that the solid solution of CuO and B$_2$O$_3$ might be responsible for the decrease of the sintering temperature of the specimens. A dense microstructure without pores was developed with the addition of a small amount of CuO. However, a porous microstructure with large pores was formed when a large amount of CuO was added. The bulk density, the dielectric constant ($\varepsilon$$_{r}$) and the Q-value increased with the addition of CuO but they decreased when a large amount of CuO was added. The variations of those properties are closely related to the variation of the microstructure. The excellent microwave dielectric properties of Qxf = 21500 GHz, $\varepsilon$$_{r}$ = 31 and temperature coefficient of resonance frequency($\tau$$_{f}$) = 21.3 ppm/$^{\circ}C$ were obtained for the Ba(Mg$_{1}$3/Nb$_{2}$3/)O$_3$+2.0 mol%B$_2$O$_3$+10.0 mol%CuO ceramic sintered at 875 $^{\circ}C$ for 2 h.h.2 h.h.

• Journal of Biomedical Engineering Research
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• v.23 no.3
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• pp.189-196
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• 2002

Transdermal drug delivery offers an alternative method to the conventional oral and injection delivery method. Its advantages include its ability to deliver drugs directly into systemic circulation. However, there have been restrictions in its application to deliver drugs because of the skin's barrier function. In this study, we try to combine a Sonophoresis and oxygen Pressure method in order to increase the Permeability of the skin. we used water as the compound and by utilizing the skin impedance method. we measured the hydration Permeability of skin Ultrasound was applied using a sonicator(Solcare-U1000. Solco, Korea) operating at a frequency of 1MHz. oxygen Pressure was applied using a compressor(Oxyjet-Pointer, Nora Bode. Germany) operating at a pressure of 2Bar/cm2. Experiment was performed in vivo for 42 People. We divided the subjects into four smaller groups. A different transdermal drug delivery method was applied for each group on the back of their hand. We measured the skin impedance variations on the hand. during a 20-minute time Period. The control group did not show any significant increase or variation of skin impedance to water. In comparison to the control group(Passive diffusion) the hydration Permeability of the ultrasound group and the oxygen Pressure group was approximately 25 and 30 times higher consecutively. Futhermore, the hydration permeability of the combination of ultrasound and oxygen Pressure group was about 70-fold higher in comparison to the control group(passive diffusion) . The results reveal that a combination of ultrasound and oxygen Pressure will significantly enhance transdermal water transport compared when only one of them is used.

• Journal of Astronomy and Space Sciences
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• v.14 no.2
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• pp.330-346
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• 1997

Korea Multi-Purpose Satellite I (KOMPSAT-I, the first multi-purpose Korean satellite) will be launched in the third quarter of 1999, which is operated on the sun-synchronous orbit for cartography, ocean color monitoring, and space environment monitoring. The main mission of Electro-Optical Camera(EOC) which is one of KOMPSAT-I sensors is to provide images for the production of scale maps of Korea. EOC collects panchromatic imagery with the ground sample distance of 6.6m at nadir through visible spectral band of 510~730nm. For determining KOMPSAT-I crossing time over Korea, this study examines the diurnal variation of solar and atmospheric variables that can exert a great influence on the EOC imagery. The results are as follows: 1) After 10:30 a.m. at the winter solstice, solar zenith angle is less than $70^{\circ}$ and expected flux of EOC spectral band over land for clear sky is greater than about $2.4mW/cm^2$. 2) For daytime the distribution of cloud cover (clear sky) shows minimum (maximum) at about 11:00 a.m. Although the occurrence frequency of poor visibility by fog decreases from early morning toward noon, its effect on the distribution of clear sky is negligible. From the above examination it is concluded that determining KOMPSAT-I crossing time over Korea between 10:30 and 11:30 a.m. is adequate.

• Journal of Energy Engineering
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• v.21 no.2
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• pp.152-157
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• 2012

Due to the global warming and energy exhaustion, energy efficiency improvement of construction is recognized the stream of times. To improve the efficiency of the building, in order to energy saving, passive elements should be applied. Then the first step be supposed that applying the new standards about the insulation boundary. The current insulation boundary standards are not reasonable as well as does not divide the purposes. As a result, energy is being wasted and many civil complaints are also occurred. To improve these problems, applying the insulation boundary need to divide the heating and non-heating and subdivide the purpose of construction. In this study, accurate real heating and air conditioning areas are presented that work on the new insulation boundary of purposes and applicable standards. This proposed, by the real heating and air conditioning areas, insulation boundary of purposes, matching the reasonable capacity and load of equipment, by working on standards by optimal maintenance can be energy saving, to present guidelines that environment improvement of actual residents as well as energy saving be expected.

• Korean Journal of Applied Biomechanics
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• v.17 no.4
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• pp.115-125
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• 2007

Grould Reaction force(GRF) is important in human movements and GRF measurements are one of the most frequently used tool in biomechanical studies. In the studies of the golf swing motion, people refer to GRF as weight transfer. A successful golf swing motion requires many segments activation sequences which are controled by the nerve system. Due to the inter- and intra-individual variability of the human movement and the movement strategies, reliability of the measurements are important in human movement studies. Previous golf researches were based on group studies and certain events' values were analyzed. The purposes of this study were to determine the number of trials for the reliable golf swing GRF data collection, to reveal the variability level of the meaningful components of the golf swing GRF, and to classify the types of the golf swing GRF patterns. Twenty three male professional golfers($26.4{\pm}6.6$ years, $174.3{\pm}5.2\;cm$, $71.3{\pm}6.5\;kg$) signed an informed consent form prior to participation in this study. GRFs of driver swings were collected with Kistler 9285 force platform and 9865A amplifier, and calculated by the KwonGRF program(Visol, Korea). Sampling frequency was 1080 Hz. GRF data were trimmed from 1.5 s prior to the impact to 0.5 s after the impact. The number of trials for the reliable GRF collection was determined when the change in floating mean overs the 25 % of the standard deviation of that variable. Variabilities of the variables were determined by the coefficient of variation(CV) of 10 %. The types of GRF patterns were determined by visual inspection of the peak GRF shapes. The minimum number of trials for the reliable golf swing GRF data collection was five. Ten-trial seems more conservative. The value of the peak GRF was more reliable than the value of the impact GRF. The CV of the peak GRF and impact GRF were 7.4 %, 15.2 %, respectively. Because of the +/- sigh of the peak GRF appearance time, it was impossible to calculate CV of the peak GRF appearance time. Golf swing GRF patterns were classified as sing peak type, double peak type, and plateau peak type. This classification suggests the presence of the different golf swing weight transfer strategies.

• Toxicological Research
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• v.22 no.4
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• pp.417-422
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• 2006

Cytogenetic and hematological analysis was performed in peripheral blood obtained from cattle bred in the high background radiation areas (HBRA, Goesan-gun, Cheongwon-gun, Boeun-gun) and a control area. The frequencies of gamma-ray induced micronuclei (MN) in the cytokinesis-blocked (CB) lymphocytes at several doses were measured in 3 cattle. An estimated dose of radiation was calculated by a best fitting linear-quadratic model based on the radiation-induced MN formation from the bovine lymphocytes exposed in vitro to radiation over the range from 0 mGy to 1,969 mGy. The measurements performed after irradiation showed dose-related increases in the MN frequency in each donors. The results were analyzed using a linear-quadratic model with a line of best fit of $y=(0.0583{\pm}0.0137)D+(0.0366{\pm}0.0081)D^2+(0.0093{\pm}0.0015)$ (y=number of MN/CB cells and D=irradiation dose in Gy). MN rates per 1,000 CB lymphocytes of cattle from the Goesan-gun, Cheongwon-gun, Boeun-gun and the control area were $6.50{\pm}2.72,\;9.00{\pm}4.50,\;10.89{\pm}4.23\;and\;9.60{\pm}4.70$, respectively. The MN frequencies of CB lymphocytes from cattle bred in 4 areas mean that the values are within the background variation in this experiment. The MN frequencies and hematological values were similar regardless of whether the cattle were bred in the HBRA or the control area.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.4
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• pp.239-244
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• 2015

Each biological tissue has endemic electrical characteristics owing to various differences such as those in cellular arrangement or organization form. The endemic electrical characteristics change when any biological change occurs. This work is a preliminary study surveying the changes in the electrical characteristics of biological tissue caused by radiation exposure. For protection aganinst radiation hazards, therefore the electrical characteristics of living tissue were evaluated after development of the automatic control measurement system using LabVIEW. No alteration of biological tissues was observed before and after measurement of the electrical characteristics, and the biblogical tissues exhibited similar patterns. Through repeated measurements using the impedance/gain-phase analyzer, the coefficient of variation was determined as within 10%. The reproducibility impedance phase difference in electrical characteristics of the biological tissue did not change, and the tissue had resistance. The absolute value of impedance decreased constantly in proportion to the frequency. It has become possible to understand the electrical characteristics of biological tissues through the measurements made possible by the use of the developed. automatic control system.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.16 no.3
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• pp.135-140
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• 2016

Purpose: Galactose is metabolized to galactose-1-phosphate by galactokinase (GALK), galactose-1-phosphate uridyltransferase (GALT) and UDP-galactose-4-epimerase (GALE), and galactosemia occurs when each enzyme is deficient. In Korea, unlike foreign countries, classic galactosemia is rare and transient galactosemia due to GALK hyperactivity is reported, but studies on frequency, clinical significance, and genetic variation are lacking. In this study, we analyzed the clinical characteristics of patients with galactosemia due to GALK hyperactivity. Methods: We investigated 85 patients who had an elevated galactose level in the neonatal screening test without deficiency of enzymes at Department of Pediatrics, Seoul & Bucheon Soonchunhyang University Hospital from January 2008 to June 2016. We investigated the level of galactose, galactose-1-phosphate, GALK and duration of galactose normalization, and analyzed the correlation between GALK elevation and galactose, galactose-1-phosphate and duration of galactose normalization. And the levels of galactose, galactose-1-phosphate, and duration of galactose normalization were compared between the galactose-free formula feeding group and non-feeding group. Results: Mean age of visit was $26.7{\pm}16.1days$. Duration of galactose normalization was $35.3{\pm}20.5days$. Mean galactose level was $18.5{\pm}7.3mg/dL$ in the neonatal screening and follow-up galactose level in serum was $2.3{\pm}5.4mg/dL$. The mean value of galactose-1-phosphate was $6.0{\pm}4.7mg/dL$ and the mean GALK level was $3.84{\pm}1.28{\mu}mol/Hr/gHb$. There was no significant correlation between GALK levels and galactose levels in the neonatal screening test (P=0.351), and we analyzed the correlation between GALK levels and follow-up galactose levels in serum, there was no significant correlation (P=0.101). There was a significant correlation between GALK levels and galactose-1-phosphate (P=0.015), and the correlation between GALK levels and duration of galactose normalization was not statistically significant (P=0.176). 49% of the patients were fed galactose-free formula, and 45% were not. Galactose and galactose-1-phosphate levels in the neonatal screening test were statistically significantly higher (P=0.004, 0.034) in using galactose-free formula group. Duration of galactose normalization was not related to the use of galactose-free formula (P=0.266, 0.249). Conclusion: Galactosemia due to GALK hyperactivity seems to be a temporary phenomenon and may not require galactose restriction. More research is needed on the role of the nuclear protein, racial traits and genetic variations in Korean patients.

• Journal of Preventive Medicine and Public Health
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• v.14 no.1
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• pp.111-116
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• 1981

Economic development of Korea brought rapid progress and expansion of her industries. Accordingly, number of workers who have been exposed to hazardous metals are increasing. For better understanding the significance of on the job human metal pollution, a total of 22 solderers among autoworkers and 28 controls among medical students was purposively selected as samples of the study. From their blood, concentrations of cadmium and lead were measured with atomic absorption spectrophotometer, and to compare with statistical indices of controls those of solderers were sumarized as follows. 1. Each frequency distribution of cadmium and lead concentration in blood of solderers was more positively skewed showing non-Gausian distribution. 2. Interindividual variation of lead concentration in blood of solderers was markedly revealed. 3. Each mean of cadmium and lead concentration in blood of solderers was higher than that of controls(Cd;p<0.01, Pb;p<0.01). 4. Relative ratio of cadmium concentration in blood of solderers to that of controls was 1.36 by arithmatic mean and 1.39 by geometric mean. Relative ratio of lead concentration in blood of solderers to that of controls was 1.53 by arithmatic mean and 1.30 by geometric mean. 5. It was shown that concentration of lead is slightly correlated with that of cadmium both in solderers and controls(solderers; p<0.1, controls;p<0.1).

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.3
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• pp.504-511
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• 2010

Diabetes is a disease that contains a high concentration of glucose in blood and due to defects in either insulin secretion or insulin action. Although the distinctive causes and factors of diabetes have not been clarified, the genetic factors are suggested as a main susceptibility until now. SNP (Single Nucleotide Polymorphism), as the most common genetic variation, has an influence on personal susceptibility for diseases. A nonsynonymous SNP, which changes the amino acid of the protein and its function, is especially important. Therefore, this study hypothesized that there are associations between specific SNPs of the targeted genes. Transcription factor 7-like 2 (TCF7L2) and fat mass and obesity associated (FTO) genes were selected as target genes from the results of genome-wide association and other related research studies. Second, four nonsynonymous SNPs (three in TCF7L2 and one in FTO gene) were selected as target SNPs by using public database of NCBI (National Center for Biotechnology Information). The recruited personnel was classified into three subgroups of diabetes, impaired fasting glucose (IFG) and normal groups. The individual genotypes of each group were analyzed by resequencing. None of genetic variations at four targeted SNP sites was revealed in all samples of this study. However, this study found two new SNPs that were not reported in TCF7L2 gene. One is synonymous SNP, which is heterozygous of C/T and no amino acid change of asparagine/asparagines, was located at c1641 and found in one normal person. Another is nonsynonymous SNP, which is heterozygous of G/A, was located at c1501 and found in two samples. This new discovered nonsynonymous SNP induce the amino acid change from alanine to threonine. Moreover, this new nonsynonymous SNP was found among two persons, one of whom was a diabetes patient and the other one was a person at boundary between IFG and normal, suggesting that this variant might be associated with IFG or diabetes. Even if there is a limitation of sample number for statistical power, this study has an importance due to the discovery of new SNPs. In the future study, a large sample number of diabetes cohort will be needed to investigate the frequency and association with new discovered SNP.