• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.9
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• pp.788-793
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• 2002

The glass-electroceramics were composed of glass composition(CaO, $SiO_2$, $B_2$ $O_3$) and electroceramic composition(BaO, N $d_2$ $O_3$, B $i_2$ $O_3$ and Ti $O_2$) Their dielectric properties have been investigated as a function of sintering temperature and glass contents. In the ceramics composed of 0.16BaO-0.15(N $d_{0.87}$,B $i_{0.13}$)$_2$ $O_3$-0.69Ti $O_2$with glass ［EG-2782］ 3wt% addition and sintered at 108$0^{\circ}C$ for 2h, we could obtain microwave properties of dielectric constant $\varepsilon$$_{r}$ = 80.1, quality factor Q $\times$f = 810(at 3.5 GHz) and temperature coefficient of resonant frequency $\tau$$_{f}$ = -1.3 ［ppm/$^{\circ}C$］. These experimental results show that dielectric constant and temperature coefficient of resonant frequency could be estimated by empirical equations involving the rule of mixture.e.

• Journal of The Korean Association For Science Education
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• v.16 no.4
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• pp.451-460
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• 1996

The ethical issue is one of the most important themes in both science and environmental education. Especially related to the right of other species, animal dissection has been brought about two contradictory attitudes. In spring 1996, a survey was conducted to assess the status of animal dissection in secondary schools and the awareness of 94 biology teachers and 422 secondary students toward animal dissection. And the meaning of animal dissection in biology class was discussed in terms of environmental education. The findings were as follows: First, most of students(96.6%) had participated once or twice to animal dissection experiments(eg. fish, frog, shellfish, cuttlefish and chicken). And about half of teachers (57.4$\sim$64.9%) and some students(41.9%) felt ethical conflict in animal dissection. Second, many teachers(81.0%) and students(87.1%) thought that animal dissection was effective method to achieve the goal of biology education, but they needed more consideration on the respect for life in animal dissection experiment. Third, many teachers(88.3%) had students, who objected to animal dissection, participate obligatorily or passively. Fourth, teachers and students thought that audio-visual media such as video(teachers 63.5%, students 39.7%), computer simulations(teachers 31.7%, students 28.1%) and models(teachers 22.2%, students 24.1%) could be effective as alternatives. These findings suggest that animal dissection experiment, although it is needed to achieve the goal of biology education, requires careful consideration on the rights of animal and the respect for life, and alternatives for students who object to animal dissection in biology class.

• Current Photovoltaic Research
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• v.3 no.1
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• pp.16-20
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• 2015

Ag addition in chalcopyrite materials is known to lead beneficial changes in aspects of structural and electronic properties. In this work, the effects of Ag alloying of $Cu(In,Ga)Se_2$-based solar cells has been investigated. Wide bandgap $(Ag,Cu)(In_{1-x},Ga_x)Se_2$ (x = 0.75~0.8) films have been deposited using a three-stage co-evaporation with various Ag/(Ag+Cu) ratios. With Ag alloying the $(Ag,Cu)(In_{1-x},Ga_x)Se_2$ (x~0.8) films were found to have greater grainsize and film thickness. Device were also fabricated with the $(Ag,Cu)(In_{1-x},Ga_x)Se_2$ (x~0.8) films and their J-V and quantum efficiency measurements were carried out. The highest-efficiency $(Ag,Cu)(In_{1-x},Ga_x)Se_2$ solar cell with Eg > 1.5 eV had an efficiency of 12.2% with device parameters $V_{OC}=0.810V$, $J_{SC}=21.7mA/cm^2$, and FF = 69.0%.

• Korean Journal of Community Nutrition
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• v.5 no.2
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• pp.185-192
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• 2000

As the percentage of the elderly in the population increases, research to identify the nutritional and health status of the elderly, to understand the factors influencing on them, and to delay aging have been done actively. It is necessary for these studies to be longitudinal. This study was carried out to assess the change of health-related habits such as dietary behaviors and smoking, alcohol drinking and exercising habit, and health status between previous study(1991/1994) and post study(1998) for middle-aged men and women living in Chonju. For the present study, the data of 63 pairs(23 men and 40 women) were analyzed. They were 11 men and 12 women followed up from 82 men and 100 women surveyed in 1994. Mean ages in the 1991/4 and 1998 studies were 53.6y(range 42-63y) and 59.0y(range 46-72y) respectively. The survey was conducted with interview using a questionnaire including dietary behaviors and health-related habits, and anthropometric measurement and blood test for analyzing biochemical indices in 1991/4 and 1998. To understand these changes over time, $\chi$$^2$-statistics, t-test and paired t-test were analyzed with an SAS package program. As people age, there were significantly decreases in the proportions to eat lightly salted foods and drink alcohol. Significant longitudinal increases in triceps skin fold thickness, ${\gamma}$-GPT and HDL-cholesterol and significant decrease in hemoglobin value were noted over time in both men and women. In addition a significant decrease in blood glucose level was noted over time in women. Weight, blood glucose and total cholesterol increased significantly with age in those had had breakfast regularly or those had not used more slat at the table in the past. From this study, were found out the subjects of this study had relatively desirable health-related habits. But as improper health-related habits are likely to result in inappropriate health status(eg, increase in WHR, triglyceride, total cholesterol and LDL-cholesterol), it is recommended that nutrition education in necessary as soon as possible to meet the health elderly.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.204.2-204.2
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• 2013

Wide band gap II-VI semiconductors have attracted the interest of many research groups during the past few years due to the possibility of their applications in light-emitting diodes and laser diodes. Among the II-VI semiconductors, ZnO is an important optoelectronic device material for use in the violet and blue regions because of its wide direct band gap (Eg ~3.37 eV) and large exciton binding energy (60 meV). F-doped ZnO (FZO) and undoped ZnO thin films were grown onto quartz substrate by the sol-gel spin-coating method. The doping level in the solution, designated by F/Zn atomic ratio of was varied from 0 to 5 in 1 steps. To investigate the effects of the structure and optical properties of FZO thin films were investigated using X-ray diffraction (XRD), UV-visible spectroscopy, and photoluminescence (PL). In the XRD, the residual stress, FWHM, bond length, and average grain size were changed with increasing the doping concentration. For the PL spectra, the high INBE/IDLE ratio of the FZO thin films doping concentration at 1 at.% than the other samples.

• Korean journal of food and cookery science
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• v.5 no.1
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• pp.1-8
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• 1989

The study on the change of general properties of Kagdugi during dfermentation reveals that around the third day of fermentation, optimum for good flavor, the pH decreased to around or below 4 while the acidity increased gradually. The relative amount of thiocyanate in the radish Kimchi homogenate decreased to 73% after 1 day and after 3 days to 32% of control. And the content of indolylmethyl glucosinolate and total myrosinase activity in the tissue of radish Kimchi decreased gradually and on 3rd day to 25% and 4% of control, respectively. On the other hand the concentration of ascorbic acid in the radish Kimchi was found to vary around 1mM. Based on these results, the gradual decline of thiocyanate formation in the radish Kimchi homogenate is concluded to be caused by the gradual decomposition of indolylmethyl glucosinolate and the decline of myrosinase activity, which are directly affected by the change of pH during fermentation.

• Journal of radiological science and technology
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• v.39 no.2
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• pp.135-142
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• 2016

The purpose of this study is to evaluate propriety of using SID 180cm at Chest PA examination and to find effect of geometrical cause to the image. XGEO-GC80, INNOVISION-SH, CXDI-40EG detector and a chest phantom designed self-production was used for this study. Images were acquired at SID 180cm with changing the factor OID as 0, 75 and 83mm and were analyzed by Centricity Radiography RA1000 PACS system. Statistical program was used the SPSS (Version 22.0, SPSS, Chicago, IL, USA), p-value(under 0.05) was considered to be statistically significant. In OID 0 mm was enlarged about 2.7~3.5 mm than the actual degree of the HS, BS of phantom in all equipments. Compared with the calculated magnification has been expanded 1.6~2.8% when viewed. The OID 75 mm with OID 83 mm was extended from the CS and BS 6~8 mm range. Compared to the calculated values, the measured values are expanded from 6.1 to 7.9%. CS and BS according to the OID change showed a statistically significant difference (p<0.05) among each group, the post-analysis only OID 0 mm group appeared as an independent group, 75 mm and 83 mm are separated in the same group It was. But had no statistically significant difference could change depending on the OID (p>0.05), post-mortem analysis showed, both in the same group. Heart sizes appears larger than actual size 6~8 mm at chest PA examination which is enlarged 6.1~7.9% more than the actual theoretical value. We can find magnification of the image because of the increase of the OID due to technical limitations between cover of standing detector and the image plate. so we suggest to have occurred between them when considering the need to adjust the equipment installed by the SID to match the characteristics of the equipment.

• Korean Journal of Food Science and Technology
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• v.38 no.1
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• pp.104-108
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• 2006

Water extracts of Jehotang were evaluated for their growth-promoting effects on Bifidobacterium longum, Lactobacillus sp., L. acidophilus, and Clostridium perfringens. Addition of Jehotang water extract to modified EG media at 0.1 mg/mL increased growths of B. longum, Lactobacillus sp., and L. acidophilus, with 1.8-fold increase in growth of L. acidophilus compared to that of control. Studies on these strains by agar diffusion method showed Lactobacillus sp. and L. acidophilus were activated by addition of Jehotang extract at 10 mg/disc. Proliferation responses of mice splenocytes and Peyer's patch cells to ConA by LPS-stimulation at 500 mg/kg B.W./day Jehotang extract were investigated in vitro. Upon treatment of 1 mg/mL Jehotang water extract to mice, proliferations of splenocytes and Peyer's patch cells increased 1.4- and 1.6-fold compared to control, respectively. In mice administered Jehotang extract, production of intestinal secretory IgA (sIgA) increased 2.4-fold compared to control. These results indicate water extract of Jehotang stimulated intestinal immune system of mice. In mice treated with Jehotang extract, production of lymphocytes was 4% lower, whereas those of granulocytes and platelets were 4% and slightly higher than control, respectively.

• Korean Journal of Animal Reproduction
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• v.20 no.2
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• pp.119-126
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• 1996

This study was carried out to determine the optimal condition for successful and efficient c cryopreservation of zygotes, 1-cell embryos, using EFS40 which was 40% (v/v) ethylene glycol diluted in DPBS medium containing 30% Fic-oll (w/v) and 0.3 M sucrose. After mouse zygote produced by IVF was vitrified by two freezing methods, the post-warming survival rates of 1-cell zygotes were assessed as cleavage to the 2-cell stage and development into the hatching blastocysts at 5 day. In the one-step method, when embryos were directly exposed to the vitrification solution at 25$^{\circ}C$ for 1 min., survival and development rates of zygotes were 85.5% and 31.9% In the two-step method, embryos were equilibrated with a dilute 20% EG for 1, 3, 5 min. before 1 min. exposure to EFS40, re-spectively. However, the rates of development (17.7, 3.3, 0%) were lower than that of one-step method. The highest survival rate (95.9%) was obtained by one-step method which exposes embryos in EFS40 for 30 sec. In this condition, 63. 8% of cleaved 2-cell developed into hatching blastocysts. In the cell number of Total and ICM using differential labelling technique, there are no significant differences in the cell number of Total and ICM between blastocysts devel oped in vitrified-thawed embryos (63.2${\pm}$16.9, 1 13.5${\pm}$4.0) and control balstocysts (54.0${\pm}$15.2, 1 12.3${\pm}$4.6). Therefore, these results show that mouse zygotes can be successfully cryopreserved by a simple vitrification method although developmental rates of vitrified embryos were reduced. In conclusion, this proposed vitrifi cation procedures can be useful in the cryopreservation of mouse IVF zygotes.

• Journal of the Korean institute of surface engineering
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• v.41 no.5
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• pp.226-231
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• 2008

Titanium and its alloy have been widely used in dental implant and orthopedic prostheses. Electrochemical characteristics of dental implant in the various simulated body fluids have been researched by using electrochemical methods. Ti-6Al-4V alloy implant was used for corrosion test in 0.9% NaCl, artificial saliva and simulated body fluids. The surface morphology was observed using scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX). The electrochemical stability was investigated using potentiosat (EG&G Co, 263A). The corrosion surface was observed using scanning electron microscopy (SEM). From the results of potentiodynamic test in various solution, the current density of implant tested in SBF and AS solution was lower than that of implant tested in 0.9% NaCl solution. From the results of passive film stability test, the variation of current density at constant 250 mV showed the consistent with time in the case of implant tested in SBF and AS solution, whereas, the current density at constant 250mV in the case of implant tested in 0.9% NaCl solution showed higher compared to SBF and AS solution as time increased. From the results of cyclic potentiodynamic test, the pitting potential and |$E_{pit}\;-\;E_{corr}$| of implant tested in SBF and AS solution were higher than those of implant tested in 0.9% NaCl solution.