• Asian-Australasian Journal of Animal Sciences
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• v.19 no.3
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• pp.319-323
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• 2006

Heritabilities and genetic correlations of economic traits were estimated with a multiple-trait animal model on 5 different strains of Korea Native Chickens (KNC): Red Brown (RB), Yellow Brown (YB), Gray Brown (GB), Black (B) and White (W). The data used for this study were collected from the Daejeon branch of the National Livestock Research Institute and included 11,233 performance records and 12,729 individual animals. DFREML and SAS BASE/STAT packages were used to estimate genetic parameters and descriptive statistics. The estimated heritabilities for strain RB, YB, GB, B and W, respectively, for age at 1st egg were 0.24, 0.27, 0.12, 0.32 and 0.18; for body weight at first egg were 0.39, 0.43, 0.38, 0.52 and 0.57; for body weight at age of 270 days were 0.43, 0.51, 0.30, 0.52 and 0.67; for egg weight at first egg were 0.08, 0.13, 0.07, 0.06 and 0.07; for egg weight at age of 270 days were 0.37, 0.43, 0.22, 0.34 and 0.41; and for number of eggs laid by age of 270 days were 0.24, 0.25, 0.37, 0.36 and 0.30. The genetic and phenotypic correlations were also estimated.

• Korean Journal of Veterinary Service
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• v.33 no.3
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• pp.299-302
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• 2010

This study was conducted to determine the content of heavy metals in meats available on the Korean markets. Trace metals (Pb, As and Cd) were detected in 4 kinds, 172 samples by inductively coupled plasma-mass spectrometry (ICP-MS). The values of heavy metals in meats were as follows; In beef, mean (minimum~maximum) values of the heavy metals were Pb: 0.075 (0.020~0.190)mg/kg, As: 0.010 (0.001~0.050)mg/kg and Cd: 0.43(0.07~2.11)${\mu}g/kg$. In pork, mean (minimum~maximum) values of the heavy metals were Pb: 0.065 (0.012~0.171)mg/kg, As: 0.004 (ND~0.021)mg/kg and Cd: 0.43(0.08~1.09)${\mu}g/kg$. In chiken, mean (minimum~maximum) values of the heavy metals were Pb: 0.060(0.016~0.211)mg/kg, As: 0.008 (ND~0.042)mg/kg and Cd: 0.42 (0.02~3.80)${\mu}g/kg$. In duck, mean (minimum~maximum) values of the heavy metals were Pb: 0.070 (0.011~0.157)mg/kg, As: 0.005 (0.001~0.011)mg/kg and Cd: 0.87 (0.15~3.75)${\mu}g/kg$. This results will be used as a basic data for the future legislation on the regulation and control of heavy metal in meats.

• Communications of Mathematical Education
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• v.24 no.2
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• pp.283-300
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• 2010

It has been recognized for a long time that high school students have difficulty in properly interpreting the form $0^0$. The treatment of $0^0$ was still a subject of a slight controversy among mathematicians until relatively recently. Since the mathematics curriculum in high school does not provide the definite treatment of $0^0$, some students might be inclined to ask what the value of the form is. In this research, we review materials dealing with $0^0$ and analyze historically and mathematically the form, whose true meaning is an indeterminate form. We identify the reality of the mathematics education in high school by conducting simple surveys targeting some high school teachers and the students who graduated from high schools recently. Then we discuss, for teachers and pre-service teachers, how to teach the form $0^0$ in high school mathematics.

• Journal of the Korean Chemical Society
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• v.20 no.4
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• pp.260-265
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• 1976

The conductances of dilute solutions of LiCl, NaCl and KCl in a series of isopropanol-water mixtures were determined at $30^{\circ}C$. The values of equivalent conductance agreed well with Debye-Huckel-Onsager equation and the limiting equivalent conductance was greatly reduced as the isopropanol content of the solvent was increased in accord with predictions based on solvent viscosity and dielectric properties. Also, the limiting equivalent conductance increased in sequence ${\Lambda}_{0,LiCl} < {\Lambda}_{0,NaCl} < {\Lambda}_{0,KCl} in 0.0, 0.1 and 0.2 mole fraction isopropanol, but {\Lambda}_{0,LiCl} < {\Lambda}_{0,KCl} < {\Lambda}_{0,NaCl} in 0.3 mole fraction ispropanol. The maximum Walden product, {\Lambda}_{0{\eta}0}$ was found in 0.1 mole fraction isopropanol for all electrolytes.

• Journal of the Korean Magnetics Society
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• v.8 no.4
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• pp.203-209
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• 1998

Crystallographic and magnetic properties of single phase garnet $Y_{3-x}Bi_xFe_5O_{12}$ (x=0.0, 0.25, 0.5, 0.75, 1.0) were studied by using x-ray diffraction, Mossbauer spectroscopy and vibrating sample magnetometer (VSM). Ultra-fine polycrystalline cubic samples have been prepared by sol-gel method. The lattice constant increase linearly with increasing an amount of Bi. Annealing temperature was larger than 800 $^{\circ}C$ for the growth of a single-phase garnet powder. The second phase of garnet, $(BiFeO_3)$, was at 1000 $^{\circ}C$ for x=0.75, and 950 $^{\circ}C$ for x=1.00. From Mossbauer spectroscopy and VSM measurements, the magnetization and the coercivity were decreased and the Curie temperature $Y_{3-x}Bi_xFe_5O_{12}$(x=0.0, 0.25, 0.5, 0.75, 1.0) was slightly increased as increasing the Bi content.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.9
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• pp.728-732
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• 2011

In this study, piezoelectric and dielectric properties of Lead-free $0.97[(K_{0.5}Na_{0.5})(Nb_{0.97}Sb_{0.03})O_3]+0.03[(Bi_{0.5}K_{0.5})TiO_3]$ (abbreviated as 0.97NKNS-0.03BKT)ceramics synthesized by conventional solid-state reaction process were investigated as a function of $K_{5.4}Cu_{1.3}Ta_{10}O_{29}$ addition. The results indicated that the $K_{5.4}Cu_{1.3}Ta_{10}O_{29}$ addition significantly improved the sinterability, grain growth and piezoelctric properties of 0.97NKNS-0.03BKT ceramics. The optimum values as planar piezoelectric coupling coefficient ($k_p$= 0.355), piezoelectric constant ($d_{33}$= 207 pC/N) and mechanical quality factor ($Q_m$= 128) were obtained when 0.009KCT was added. The electromechanical coupling factor($k_p$) was slightly decreased according to the increasing temperature.

• Korean Journal of Veterinary Service
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• v.15 no.2
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• pp.144-149
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• 1992

The study was attempted to scrutinize the normal osmotic fragility of erythrocytes in domestic poultry such as chicken, quail and duck making a comparison with that in domestic mammalia such as dog and pig. Osmotic fragility of erythrocytes was determined on blood samples from 10 healthy adult animal in each species. Optical initial hemolysis of erytyrocytes occurred at $0.395{\pm}0.03%$ Nacl for chicken, $0.410{\pm}0.03%$ for duck, $0.440{\pm}0.02%$ for quail, $0.470{\pm}0.05%$ for dog and $0.560{\pm}0.03%$ for pig. Optical complete hemolysis of erytyrocytes occurred at $0.270{\pm}0.02%$ Nacl for chicken, $305{\pm0}.03%$ for duck, $0.360{\pm}0.02%$ for quail, $0.370{\pm}0.03%$ for dog and $0.455{\pm}0.03%$ for p. In other words, erythrocytes of poultry have stronger resistance to osmotic Iysis than that of mammalia, showing the strongest resistance In chicken among the tested poultry.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.320-323
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• 1997

The microwave dielectric properties of X Ba0-$0.15(Nd_{0.87}Bi_{0.13})_2O_3$-(0.85-X) $TiO_2$ ($X=0.13{\sim}0.17$) and 0.16Ba0-$0.15(Bi_xNd_{1-x})_2O_3-0.69TiO_2$ ($X=0.10{\sim}0.16$) ceramics were investigated. Dielectric constant, quality factor and temperature coefficient of resonant frequency of 0.16Ba0-$0.15(Nd_{0.87}Bi_{0.13})_2O_3-0.69TiO_2$ ceramics sintered at $1320^{\circ}C$ for 2 hours were 89.2, 1920(at 4GHz) and 5.2ppm/$^{\circ}C$, respectively.

• Journal of Ceramic Processing Research
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• v.23 no.3
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• pp.243-246
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• 2022

We report the synthesis of Sn-modified LiNi0.9Co0.05Mn0.05O2 cathode via a co-precipitation method. The key factor to enhancethe electrochemical performances of lithium ion batteries is to suppress the structural reconstruction because of the irreversibilityof the H2-H3 phase transition, resulting in rapid performance decay. The as-prepared Sn-modified LiNi0.9Co0.05Mn0.05O2 cathodedelivers an initial discharge capacity of 221.4 mAh g-1 with a high coulombic efficiency of 88.5 %. Moreover, it shows betterpolarization of 0.33 V and superior cycle stability of 98.8% after 58 cycles. These values are obviously higher than those ofpristine LiNi0.9Co0.05Mn0.05O2 cathode. Therefore, we can believe that Sn-modified LiNi0.9Co0.05Mn0.05O2 cathode is one of theeffective way for high-performance cathode material in lithium ion batteries.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.5 no.3
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• pp.88-96
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• 1972

1. The present paper deals with the contents of heavy metals such as mercury, cadmium, lead and copper in 17 species of edible seaweeds collected from Jumunjin, Pohang, Pusan, Chungmu, Yeosu and Wando areas. 2. The concentration of mercury in the air-dried seaweeds ranged from 0.02 to 0.52 ppm, as shown by the following species: 0.36ppm (0.09-0.50) in Enteromorpha spp., 0.25 ppm (0.14-0.31) in Undaria sp., 0.19 ppm (0.02-0.52) in Porphyra spp., and 0.10ppm (0.02-0.24) in Laminaria spp. in that order. If these concentrations are converted to the wet bases, they will be about 1/4 to 1/5 of the present levels. In general, the samples collected from the east coast showed relatively lower levels than those from the south coast. The mercury concentrations found in the Korean seaweeds are lower than the permissible levels reported. 3. The concentration of cadmium in the air-dried seaweeds ranged from 0.02 to 1.48 ppm, and the levels in the different species showed in the following order: 0.97 ppm (0.41-1.18) in Hizikia sp., 0.33 ppm (0.03-0.63) Undaria sp., and 0.32 ppm (0.04-0.67) in Porphyra spp. The concentration of cadmium in the samples on the wet bases become 1/4 to 1/5 of the present level. The laver Porphyra spp. collected from the east coast showed relatively lower levels than those of the cultured species along the south coast. All of the concentrations are still below than the permissible levels. 4. In general, lead concentration is 0.20-1.31 ppm which is lower than the permissible level. The concentration becomes about 0.05-0.3 ppm on the wet base. 5. Copper concentration ranged from 0.90-17.0 ppn on the dry base which is about 0.2-4.0 ppm on the wet base. It is interesting to note that the samples collected from Busan region showed relatively higher levels than those sampled from other regions.