• Korean Journal of Microbiology
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• v.42 no.1
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• pp.19-25
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• 2006

This study was undertaken to develop PCR primers for the identification and detection of Streptococcus mutans (by)using species-specific forward and universal reverse primers. These primers targeted the variable regions of the 16S ribosomal RNA coding gene (rDNA). The primer specificity was tested against 11S. mutans strains and 10 different species (22 strains) of oral bacteria. The primer sensitivity was determined by testing serial dilutions of the purified genomic DNA of S. mutans ATCC $25175^T$. The data showed that species-specific amplicons were obtained from all the S. mutans strains tested, which was not observed in the other species. The direct and nested PCR could detect as little as 2 pg and 2 fg of the chromosomal DNA from S. mutans ATCC $25175^T$, respectively. This shows that the PCR primers are highly sensitive and applicable to the detection and identification of S. mutans.

• Journal of the Korean Chemical Society
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• v.30 no.1
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• pp.33-39
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• 1986

The x-values of nonstoichiometry chemical formulas, Sm$O_{1.5+x}$ and Zr$O_{2+x}$, have been measured in temperature range from 500$^{\circ}$C to 1000$^{\circ}$C under oxygen pressure of 2 ${\times}10^{-1}$ to 1 ${\times}10^{-5}$ atm by gravimetric method. The enthalpies of formation of defect in samarium sesquioxide and zirconium dioxide decrease with decreasing oxygen pressure and are all positive. The 1/n values calculated from the slopes of the plots of log x vs. log $PO_2$ increase with temperature and are positive values which mean the higher oxygen pressure dependence at higher temperature. From x-values and thermodynamic data, it is found out that the nonstoichiometric defect is fully ionized metal vacancy. The conduction mechanisms of the systems are also discussed with respect to the nonstoichiometric compositions.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.10
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• pp.1308-1318
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• 2010

The purpose of this study was to evaluate the effect of replacing soybean meal with treated castor meal with (CMT) or without lime (CMNT) on the nutrient intake, performance, carcass characteristics, and yield of commercial cuts of beef cattle from a feedlot. Thirty male, castrated, crossbreed zebu cattle were used in the study, with an average initial weight of $360{\pm}30.27\;kg$. Five animals were used as a control group and were slaughtered at the beginning of the experiment; the remaining animals (n = 25) were distributed in random blocks (repetitions), with body weight as the criterion for block assignment. The animals were fed a diet containing 65% corn silage and 35% of concentrate on dry matter (DM) basis. Five diets consisted of four levels of soybean meal (SM) substituted with CMT (0, 33, 67 and 100%) on a DM basis and a diet with 100% of SM replaced with CMNT. At the end of the experiment, all animals were slaughtered, and their gastrointestinal tracts were emptied to determine their empty body weights (EBW). No significant effects were observed (p>0.05) for the substitution of soybean meal with CMT on intake of dietary nutrients, the average daily body weight gain (ADG) or EBW gain (EBWG). In spite of greater (p<0.05) ricin intake for the diet containing CMNT (3.06 mg/kg BW) compared to the CMT diet (0.10 mg/kg BW/d), there were no effects (p>0.05) on intake of dietary nutrients, ADG or EBWG. The average intake of DM and the ADG were 10,664.63 and 1,353.04 g/d, respectively. Regarding carcass characteristics, only carcass yield in relation to body weight was linearly reduced (p<0.05) upon substitution of SM by CMT. There was no effect (p>0.05) of the substitution of SM by CMT or CMNT on the yield of carcass basic cuts. CMT prices that are higher than 85% of the SM price do not economically justify the use of CMT. For CMT prices between 20 and 80% of the SM price, the optimal level was 67% substitution, while for prices below 15% of the SM price, the optimal level was 100% substitution with CMT. It can be concluded that treated castor meal with 6% lime can totally replace soybean meal in beef cattle diets.

• Bulletin of the Korean Chemical Society
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• v.25 no.6
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• pp.852-858
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• 2004

Crystal structures of lanthanide complexes with NTA (NTA = nitrilotriacetate) are reported. The complexes of $[Ln(NTA)_2{\cdot}H_2O]^{3-}$ (Ln = Sm, Eu, Gd, Tb and Ho) crystallize in the orthorhombic space group Pccn. In the structures, the trivalent lanthanide ions are completely encapsulated via coordination to the two nitrogen atoms and the six carboxylate oxygen atoms of the two NTA ligands, and one water oxygen atoms. The complexes form a slightly distorted capped-square-antiprism polyhedron. Of the complexes, $[Eu(NTA)_2{\codt}H_2O]^{3-}$,\;[Tb(NTA)_2{\cdot}H_2O]^{3-}\;and\;[Dy(NTA)_2{\cdot}H_2O]^{3-}$ excited at the 325 He-Cd line produce very characteristic luminescence features, arising mostly from the f ${\to}$ f transitions. The absolute quantum yields of these complexes are determined at room temperature. Surprisingly, the $[Dy(NTA)_2{\cdot}H_2O]^{3-}$ complex is more luminescent than the $[Eu(NTA)_2{\cdot}H_2O]^{3-}\;and\;[Tb(NTA)_2{\cdot}H_2O]^{3-}$ complexes.

• Bulletin of the Korean Chemical Society
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• v.17 no.4
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• pp.321-324
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• 1996

Sr1+xSm1-xFeO4-y solid solutions with a composition range 0.00 ≤x≤1.00 have been prepared at 1200 ℃ in air under normal atmospheric pressure. All the solutions exhibit the K2NiF4-type structure of tetragonal system. Mohr salt analysis shows that the mole ratio of Fe4+ ion to Fe3+ ion or the τ value increases with the x value. Nonstoichiometric chemical formulas have been formulated from the x, τ, and y values. Electrical conductivity was measured in the temperature range of 173-373 K under atmospheric air pressure. The conductivities of each sample are varied within the semiconductivity range. The conductivity at constant temperature increases steadily with x value and activation energies are varied from 0.14 to 0.32 eV. The conduction mechanism of the ferrite system may be proposed as a hopping model of conduction electrons between the mixed valence states. The Mossbauer spectrum for the composition of x=0.00 shows a six line pattern by which the existence of Fe3+(I.S.=0.32 mm/sec) can only be identified. The spectra for the compositions of x=0.50 and 1.00 presents broad single line patterns showing a mixed valence state.

• Journal of Appropriate Technology
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• v.7 no.2
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• pp.151-161
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• 2021

The application of appropriate technologies in a developing country is an opportunity to introduce green technology which may lead people to imagine a better life. This point is at the intersection of appropriate technology and sustainable development. This research focuses on Hatphain village where there is no clean water, sewage system, or power lines. Two environmental technologies (an unpowered water purification system, Ongdalsaem and an eco-toilet system, BeeVi toilet) were introduced, based on the concepts of the environmental self- sustainable village and feces Standard Money (fSM). We found that the Ongdalsaem was effective in reducing the concentration of nitrogen and lead in the water in Hatphain. The BeeVi water-free toilet was installed, allowing urine and feces to be separated and used as compost. We strived to spread ideas of sustainability using new eco-circulation experiences and encouraging learning about environmental technology through practical and playing facilities that residents managed themselves.

• Journal of the Korea Convergence Society
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• v.8 no.10
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• pp.75-84
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• 2017

The purpose of this study is to identify the relationships among Social maturity(SM), Self-directed learning(SDL) and Self-concept of professional nursing(SCPN), and influencing factors of SCPN of nursing students. The survey was performed on 221 nursing students in two universities. Data were collected using a structured questionnaires and analysed with PASW 22.0. Study findings revealed that SCPN has a significant correlation with SM and SDL. Major satisfaction(${\beta}=.179$), Meaning on nursing(${\beta}=.274$), SM(${\beta}=.118$) and SDL(${\beta}=.211$) about SCPN were significant predictive variables. This variables accounted for 34.4% of the variance in SCPN. The findings indicate the necessity of developing educational programs to enhance nursing students's SM and SDL for increasing positive SCPN.

• Journal of the Korean Ceramic Society
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• v.39 no.3
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• pp.222-225
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• 2002

Microwave dielectric properties of the layered and functionally graded materials (FGMs) of $Mg_{0.93}Ca_{0.07}TiO_3$ (MCT) and $(Ca_{0.3}Li_{0.14}Sm_{0.42})TiO_3$(CLST) were investigated as a function of the volume ratio of two components. Dielectric constant was decreased with an increase of the volume ratio of MCT which had a lower dielectric constant thant CLST. For the layered FGMs specimens, the difference of thermal expansion coefficients between two components induced thermal strain to dielectric layers, which was confirmed by the plot of ${\Delta}$k (X-ray diffraction peak width0 versus k (scattering vector) using the double-peak Lorentzian function, f(x). Quality factor of the specimens was affected by the thermal strain of dielectric layer, especially MCT layer. For the specimen with the volume ratio of MCT/CLST = 2, the qulaity factor of the specimen showed a minimum value due to the maximum thermal strain fo MCT layer.

• Journal of Magnetics
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• v.21 no.1
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• pp.25-28
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• 2016

In the present study, bulk anisotropic nanocrystalline $SmCo_5$ magnets were prepared by hot deformation. The effect of deformation temperature on the texture and magnetic properties are presented, based on which the mechanism of plastic deformation and texture formation during the hot deformation process is discussed. Our analyses reveal that deformation temperature is one of the most important parameters that determine the texture of $SmCo_5$ grains. We suggest that diffusion creep plastic deformation occurs during hot deformation, which is very sensitive to the energy gain provided by an increase in temperature.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.9
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• pp.43-49
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• 1998

The deep hole drilling has an increasing demands because of its wide range applications and its good productivity. The BTA drills are capable of machining for having a large length to diameter ratio in single pass to higher degree of accuracy and surface finish. It's really necessary that the investigation for the deep hole drilling by the BTA drill because its required quality should be satisfied with single pass. This thesis deal with the experimental results obtained during single tube BTA system machining on SM55C steel for different machining conditions. The results of the investigation on the optimum cutting condition selecting and tool life reveals as follows. (1) The optimum cutting condition was cutting speed, V = 42 m/min and feed speed. F = 90 mm/min and the tool life was about 10 meters. (2) Surface roughness was $12\mum$ and the roundness was less using $16mum$single edge BTA drill in testing cutting condition.