• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.241-241
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• 2007

We fabricated SmBCO coated conductors(CCs) on IBAD-MgO templates using co-evaporation method. IBAD-MgO templates consist of PLD-LMO/epi-MgO/IBAD-MgO/Ni-alloy and showed good in-plane texture of below FWHM 7 degree. Evaporation rates of Sm, Ba, and Cu were precisely controlled to get the optimum composition ratio after deposition process. To optimize the oxygen partial pressure of reaction region, wide range of the partial pressure was investigated from 1 mTorr to 15 mTorr. By reducing the oxygen partial pressure to 5mTorr, (103)grains in SmBCO layer have been increased. On the other hand, there were only (001)grains in SmBCO layer deposited at 15 mTorr $O_2$. Deposition temperature was also investigated from $600^{\circ}C\;to\;800^{\circ}C$ to make high Ic SmBCO CCs. SmBCO on IBAD MgO template showed that the Ic increased gradually at higher growth temperature to $800^{\circ}C$, which the highest Jc and Ic is $2.6\;MA/cm^2$ and 500 A/cm-w., respectively.

• The Journal of the Petrological Society of Korea
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• v.9 no.3
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• pp.121-141
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• 2000

Granitic and pophyroblastic gneisses are widely distributed in the Seungju-Suncheon area, the southwestern part of the Sobacksan Massif. Two groups of metamorphic P-T conditions are recognized from granitic gneiss. $622-760^{\circ}C/6.2~7.4\;kbar$(Group I) are estimated from garnet cores and samples with weak retrograde metamorphism. $606~785^{\circ}C/3.7~5.4\;kbar$(Group II) are estimated from garnet rims which have lower pyrope and higher spessartine contents due to the effect of retrograde metamorphism. The metamorphic P-T conditions estimated from porphyroblastic gneiss are $489~669^{\circ}C$, 2.1~4.8 kbar which are similar to the P-T conditions of Group II in the granitic gneiss. The whole rock-garnet Sm/Nd isotopic ages determined from granitic and porphyroblastic gneisses are, respectively, $1417{\pm}52\;Ma\;and\;1421{\pm}14\;Ma$. These date indicate that intermediate-P/T type metamorphism represented by Group I may have occurred between the intrusion of granite gneiss and the intrusion of porphyroblastic gneiss(between 1890 Ma~2120 Ma) and two gneisses experienced low-P/T type metamorphism after the intrusion of porphyroblastic gneiss at 1417~1421 Ma.

• The Journal of the Petrological Society of Korea
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• v.5 no.2
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• pp.135-141
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• 1996

La-Ce method is one of new geochronological methods developed recently. La and Ce are one of the rare earth elements, and, with Sm-Nd system. La-Ce system is very useful in understanding the evolution processes of crust and mantle. In this paper, I introduce the basic concept of the La-Ce method, and apply it in clarifying LREE pattern of source material of leuco-granitic gneisses from the Imweon area, Kangwon-do, and K-rich granite from the Anshan area in Liaoning Province, NE China. Sm-Nd data on the Anshan K-rich granites give an age of $3.16{\pm}0.06$ Ga($2{\sigma}$), with initial $^{143}Nd/^{144}Nd$=$0.50846{\pm}0.00005$ (${\epsilon}_{Nd}$=-1.5). On the basis of Ce and Nd isotopic ratio, leucogranitic gneiss and K-rich granite has been fractionated from the source material which had had similar to CHUR (chundritic uniform reservoir). And the initial ${\epsilon}_{Nd}$ value suggest that the crustal formation age of the Liaoning Province area, NE China was early Archean.

• Progress in Superconductivity and Cryogenics
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• v.10 no.1
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• pp.52-56
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• 2008

According to the improvement of HTS conductor, HTS tapes which have the high current capacity have been recently researched in several nations. For large power application, AC loss is the most important issue in the development of AC superconducting power devices because it is closely related to the system operation efficiency. In 1st generation wire of HTS conductor, BSCCO, AC loss is too large to use for power application. Also, It is well known in recently years that YBCO CC, the 2nd generation wire, has also too much AC loss to apply to AC power devices. There are many trials to develop the new HTS wire having the low AC loss around the world. In this research, we present the measurment result of magnetization losses in SmBCO coated conductors. We measured the magnetization loss generated by perpendicularly exposed external magnetic field and compared with the analytic value of the strip model. Also, we presented the results compared with measured magnetization loss of an YBCO coated conductor.

• Current Research on Agriculture and Life Sciences
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• v.12
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• pp.57-68
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• 1994

This experiment was conducted to isolate the mutants from S118 and to investigate the physiological characteristics of R. japonicum mutants. The results obtained were as follows; Based on nodulation and acetylene reduction, nodulation of rhizobia was divided into 4 groups, i.e. slow-nodulation, earlier-nodulation, infrequent-nodulation and non-nodulation. At 5% significant level, the growth of inoculated plant with SM255 was bad, but that of HP277 was good. Root-hairs curling was induced by strains S118 and HP277 on soybean, but not by strain SM255. S118 and SM255 were found to be slow-gorwers and produced alkali, whereas strain HP277 was fast-grower and produced acid in YEM broth. In litmus milk reaction, all strains indicated alkaline reaction, and serume-zone was induced weakly by HP277. All of the strains tested in this experiment utilized sucrose. HP277 and LP268 utilized xylose, whereas S118 and SM255 did not. SM255 showed bad growth in nitrogen carriers however utilization of $Ca(NO_3)_2{\cdot}4H_2O$ by HP277 was possible at 25mM and 10mM level. To compare with S118, the protein band of SM255's cell protein electrophoresis was not developed at 0.62 Rm position.

• Environmental Engineering Research
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• v.12 no.2
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• pp.55-63
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• 2007

PCDD/Fs monitoring was carried out to estimate the contamination level in soil samples taken in the vicinity of the various incinerators throughout South Korea from July 2003 to December 2004. The levels ranged from N.D. to 130.39 pg I-TEQ/g (d.w.) with an average concentration of 11.38 pg I-TEQ/g (d.w.). The level of PCDD/Fs in this study is similar to that of other countries. Overall, the highest mean concentration in the soil was found at 250 m from the stack. In addition, the flue gases were analyzed in order to obtain the congener profiles of the PCDD/Fs emitted from the incinerators. The concentration of I-TEQ in the flue gas ranged from 0.33 to 21.5 ng TEQ/$Sm^3$. These levels were much lower than the concentration stipulated in the Korean emission criterion(40 ng TEQ/$Sm^3$ until 2005). The comparison of the congener patterns using cluster analysis showed that the incinerators and PCP are sources of PCDD/Fs in the soil samples according to the sampling point, but the possibility of unidentified combustion sources and vehicles exists in the case of complex industrial regions.

• Journal of the Korean Society for Heat Treatment
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• v.20 no.5
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• pp.237-242
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• 2007

Friction coefficient of SM45C steel was surprisingly reduced with $H_2S$ and $C_3H_8$ gas during plasma sulf-nitriding. During the plasma sulf-nitriding, 100-700 sccm of $H_2S$ gas and 100 sccm of $C_3H_8$ gas were added and working pressure and temperature were 2 torr, $500-550^{\circ}C$, respectively. As $H_2S$ gas amount increased over 500 sccm, flake-like structures were developed on top of the nitriding layer and grain size of the nitriding layer were about 100 nm. The friction coefficient for the sample treated plasma sulf-nitriding under $N_2-H_2S$ gas was 0.4 - 0.5. The structure became more finer and amorphous-like along with $N_2-H_2S-C_3H_8$ gas and the nano-sized surface microstructures resulted in high hardness and significantly low friction coefficient of 0.2.

• Journal of the Korean Chemical Society
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• v.43 no.3
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• pp.257-263
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• 1999

Ln-macrocyclic([20]DOTA) complexes, [Ln([20]DPTA)(NO_{3})(H_{2}O)](NO_{3})_{2} \cdotxH_{2}O{Ln(III)=Pr, Sm, Gd, Dy}, which had been synthesized from 2, 6-diformyl-p-cresol(DFPC), was placed in methanol for 2 days, and $[Ln([20]DPTA)(NO_{3})(CH_{3}OH)]^{2+}$ was formed. The equilibrium constants(L) for the substitution of coordinated $CH_{3}OH$ in the Ln-[20]DOTA complexes by various auxiliary ligands, $L_{a}(=monodentate ligands; pyridine, imidazole, triethylamine, diethylamine, piperidine) were determined spectroscopically at $25^{\circ}C$ and 0.1M. The pKa of auxiliary ligand is in the order of pyridine < imidazole < triethylamine < diethylamine < piperidine, however the K has shown the trend of pyridine < imidzole < diethylamine < piperidine < triethylamine.

• Bulletin of the Korean Chemical Society
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• v.22 no.1
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• pp.25-29
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• 2001

Nucleophilic substitution reactions of O-imidomethyl derivatives of phenols with OH- were studied theoretically using the semiempirical AM1 and Solvation Model 2.1 (SM2.1) methods in the gas phase and aqueous solution, respectively. In the gas phase, the two reaction paths, in which the imide (1a) or phenol (1b) is functioning as a leaving group, can occur competitively. In contrast, in aqueous solution, path (1b) becomes more favorable than (1a) because the transition states (TS) of path (1b) are more stabilized by solvent. Differences in solvation energies are caused by the structural differences of TS, i.e., the TS via path (1b) is more dissociative than that via path (1a). Therefore we conclude that the solvent effects play an important role in the hydrolysis of O-imidomethyl derivatives of phenols. However, reactivity is dependent on the acidities of both the imide and the phenol fragments since the ρz values vary progressively from 4.2 (Z' = I) to 2.5 (Z' = IV) as the acidities of imide increase. These are in good agreement with the experimental results.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.4
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• pp.255-261
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• 2007

Soil aggregates, resulting from physico-chemical and biological interactions, are important to understand carbon dynamics and material transport in soils. The objective of this study is to investigate stable macro-aggregate (> 0.25mm diameter) in wet sieving (SM) and their relation to soil properties in 15 sites. The clay contents of soils were ranged from 1% to 33%, and their land uses included bare and cultivated lands of annual upland crops, orchard, and grass. Undisturbed 3 inch cores with five replicates were sampled at topsoil (i.e., 0- to 10-cm depth), for analyzing SM and physico-chemical properties, after in situ measurement of air permeability. SM of sandy soils, with clay content less than 2%, was observed as 0%. Except the sandy soils, SM of soils mainly depended on land uses, showing 27%~35% in soils with annual plants such as vegetable and corn, 51% in orchard, and 75% in grass. This sequence of SM is probably due to the different strength of soil disturbance like tillage with different land uses. SM had significant correlation with cation exchange capacity, organic matter content, sand, clay, silt, bulk density, and exchangeable potassium (K) and magnesium (Mg), whereas fluctuating properties with fertilization such as pH, EC, and water soluble phosphorus weren't significantly correlated to the SM. Particularly, exchangeable calcium (Ca) had significant relation with SM, only except soils with oversaturating Ca. This study, therefore, suggested that SM could perceive different land uses and the change of soil properties in soils, necessarily considering soil textures and Ca over-saturation.