• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.408-411
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• 1995

Microstructure and magnetic properties of $Fe-Nd_{13.5}-Co_{15}-B_{6-8}Ga_{0-1}-Zr_{0.2-1}$ alloys during HDDR process were studied. $ZrB_{2}$ phase was detected and identified by X-Ray diffraction. Influence of Ga, Zr and Ga+Zr additions on phase relations at different stages of HDDR process was studied by X-ray diffraction and magnetic measurements.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.3
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• pp.1035-1041
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• 2012

This paper examines the effects of fundamental variables on stock returns. Therefore, the major purpose of this study is to identify fundamental variables having a systematical effect on the stock return. The paper uses panel data analysis. We find that the results of regressions say that firm size, book-to-market ratio(B/M), earning-to-price ratio(E/P), cash flow-to-price ratio(C/P) can explain the differences in average returns across stocks.

• JSTS:Journal of Semiconductor Technology and Science
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• v.8 no.4
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• pp.289-294
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• 2008

A 77 GHz 3-stage low noise amplifier (LNA) employing one common source and two cascode stages is developed using $0.13{\mu}m$ CMOS process. To compensate for the low gain which is caused by lossy silicon substrate and parasitic element of CMOS transistor, positive feedback technique using parasitic inductance of bypass capacitor is adopted to cascode stages. The developed LNA shows gain of 7.2 dB, Sl1 of -16.5 dB and S22 of -19.8 dB at 77 GHz. The return loss bandwidth of LNA is 71.6 to 80.9 GHz (12%). The die size is as small as $0.7mm\times0.8mm$ by using bias line as inter-stage matching networks. This LNA shows possibility of 77 GHz automotive RADAR system using $0.13{\mu}m$ CMOS process, which has advantage in cost compared to sub-100 nm CMOS process.

• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.280-285
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• 2014

In order to evaluate the insulation deterioration in the stator windings of five gas turbine generators(137 MVA, 13.8 kV) which has been operated for more than 13 years, diagnostic test and AC dielectric breakdown test were performed at phases A, B and C. These tests included measurements of AC current, dissipation factor, partial discharge (PD) magnitude and capacitance. ${\Delta}I$ and ${\Delta}tan{\delta}$ in all three phases (A, B and C) of No. 1 generator stator windings showed that they were in good condition but PD magnitude indicated marginally serviceable and bad level to the insulation condition. Overall analysis of the results suggested that the generator stator windings were indicated serious insulation deterioration and patterns of the PD in all three phases were analyzed to be internal, slot and spark discharges. After the diagnostic test, an AC overvoltage test was performed by gradually increasing the voltage applied to the generator stator windings until electrical insulation failure occurred, in order to determine the breakdown voltage. The breakdown voltage at phases A, B and C of No. 1 generator stator windings failed at 28.0 kV, 17.9 kV, and 21.3 kV, respectively. The breakdown voltage was lower than that expected for good-quality windings (28.6 kV) in a 13.8kV class generator. In the AC dielectric breakdown and diagnostic tests, there was a strong correlation between the breakdown voltage and the voltage at which charging current increases abruptly ($P_{i1}$, $P_{i2}$).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.165-166
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• 2006

Boron phosphide thin films were prepared on the glass substrate from boron and phosphorous alkoxide precursors by sol-gel processing. Boron phosphide sol with equivalent ratio $(CH_3O_3)B$ : $C_{18}H_{15}P$ = 13 : 2 was selected. Films spin-coated at 4000 rpm for 30 s were coated uniformly. Decomposition and crystallization behavior were examined using DSC/TGA and XRD. The films were sintered at 250, 300 and $400^{\circ}C$. It was determined that crystal structure has a rhombohedral phase. The microstructure of thin film was observed using SEM. Thin films approximately showed a visible ray transmittance of 85 %.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.67.1-67.1
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• 2003

Three new guaianolide type of sesquiterpene lactones, 8${\alpha}$-angeloyloxy-1${\alpha}$-hydroxy-3${\alpha}$,4${\alpha}$-epoxy-5${\alpha}$, 7${\alpha}$H-10(14), 11(13)-guaiadien-12,6${\alpha}$-olide (1), 8${\alpha}$-methylbutyryloxy-1${\alpha}$-hydroxy-3${\alpha}$, 4${\alpha}$-epoxy-5${\alpha}$, 7${\alpha}$H-10(14),11(13)-guaiadien-12,6${\alpha}$-olide (2), and 8${\alpha}$-isovaleryloxy-1${\alpha}$-hydroxy-3${\alpha}$, 4${\alpha}$-epoxy-5${\alpha}$, 7${\alpha}$H-10(14),11 (13)- guaiadien-12,6${\alpha}$-olide (3), together with six known sesquiterpenes, artemisolide (4), 3-methoxytanapartholide (5), deacetyllaurenobiolide (6), moxartenolide (7), arteminolide B (8), and arteminolide D (9) were isolated by bioassay-guided fractionation using the NF-kB mediated reporter gene assay system. (omitted)

• Applied Biological Chemistry
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• v.17 no.2
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• pp.125-137
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• 1974

The chemical structure of glycolipid of Selenomonas ruminantium cell wall was to be elucidated. The bacterial cells were treated in hot TCA and the glycolipid fractions were extracted by the solvent $CHCl_3\;:\;CH_3OH$ (1 : 3). The extracted glycolipids fraction was further separated by acetone extraction. The acetone soluble fraction was named as the spot A-compound. The acetone insoluble but ether soluble fraction was named as the spot B-compound. These two compounds were examined for elucidation of their chemical structure. The results were as follows: 1. The IR spectral analysis showed that O-acyl and N-acyl fatty acids were linked to glucosamine moiety in the spot A-compound. However in the spot B-compound in addition to O and N-acyl acids phosphorus was shown to be attached to glucosamine. 2. It was recognized by gas liquid chromatography that spot A compound contained beta-OH $C_{13:0}$ fatty acid in predominance in addition to the fatty acid with beta-OH $C_{9:0}$, whereas the spot B compound was composed of the predominant fatty acid of beta-OH $C_{13:0}$ with small amount of beta-OH $C_{9:0}$. 3. According to the paper chromatographic analysis of hydrazinolysis products of the spot A compound, a compound of a similar Rf value as the chitobiose was recognized, which indicated a structure of two molecules glucosamine condensed. The low Rf value of the hydrazinolysis product of the spot B-compound confirmed the presence of phosphorus attached to glucosamine. 4. The appearance of arabinose resulting from. ninhydrin decomposition of the acid hydrolyzate of the spot A compound indicated that the amino group is attached to $C_2$ of glucosamine. 5. The amount of glucosamine in the N-acetylated spot A compound decreased in half of the original content by the treatment. with $NaBH_4$, indicating that there are two molecules of glucosamines in the spot A compound. The presence of 1, 6-linkage between two molecules of glucosamine was suggested by the Morgan-Elson reaction and confirmed by the periodate decomposition test. 6. By the action of ${\beta}-N-acetyl$ glucosaminidase the N-acetylated spot A compound was completely decomposed into N-acetyl glucosamine, whereas the spot B compound was not. This indicated the spot A compound has a beta-linkage. 7. When phosphodiesterase or phosphomonoesterase acted on $^{32}P-labeled$ spot B compound, $^{32}P$ was not released by phosphodiesterase, but completely released by phosphomonoesterase. This indicated that one phosphorus is linked to glucosamine moiety. 8. The spot A compound is assumed to have the following chemical structure: That is glucosaminyl, ${\beta}-1$, 6-glucosamine to which O-acyl and N-acyl fatty acids are linked, of which the predominant fatty acid is beta-OH $C_{13:0}$ fatty acid in addition to beta-OH $C_{9:0}$ fatty acid 9. The spot B compound is likely to have the linkage of $glucosaminyl-{\beta}-1$, 6-glucosamine to which phosphorus is linked in monoester linkage. Furthermore both O-acyl and N-acyl fatty acids contained beta-OH $C_{13:0}$ fatty acid predominantly in addition to beta-OH $C_{9:0}$ fatty acid.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.1
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• pp.1-7
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• 1998

A total of 120 pigs $(L\;{\times}\;LW\;{\times}\;D)$ averaged 14.16 kg of body weight were reared under six dietary treatments to evaluate the effects of amino acid supplementation on their performances. Treatments were 1) 18% CP diet (control); 2) 15% CP+0.28% Lys (B, 15L); 3) B+0.06% Met (15LM); 4) B+0.13% Thr (15LT) ; 5) B+0.06% Met+0.13% Thr (15LMT); 6) B+0.06% Met+0.13% Thr+0.05% Trp (15LMTT). Each treatment had 4 replicates with 5 pigs per replicate. The daily weight gains were statistically similar in 15LMT, 15LMTT and control groups. Threonine and methionine supplementation resulted in improved growth performance and nutrient digestibilities, while tryptophan supplementation had little beneficial effect. However, the best feed conversion was found in the control group. Dry. matter and CP digestibilities were improved in the 15LMT and 15LMTT groups. Gross energy, crude fat and phosphorus digestibilities were not affected by the treatment. Among the 15% CP groups, nitrogen digestibility showed the tendency to be increased as the more synthetic amino acids were added. Dry matter and nitrogen excretions were significantly reduced by feeding low protein, amino acid fortified diets, while phosphorus excretion was not influenced. Essential amino acids digestibility was higher in 15LT, 15LMT and 15LMTT groups and lower in the control. The 15LT group showed the best lysine digestibility, and methionine digestibilities were higher in all treated groups than control one. Threonine digestibilities higher in 15LT 15LMT, and 15LMTT than the control. The result shows that threonine and methionine should be added to the diet containing 15% CP diet, fortified with lysine to get same performance of 18% CP diet.

• Microbiology and Biotechnology Letters
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• v.20 no.3
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• pp.271-279
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• 1992

Genomic DNA of Bacillus stearothemzophilus, which expressed alkalophilic and thermophilic xylanases, was partially digested with HindIII, cloned into pBR322, and subsequently transferred into the Escherichra coli HB101 cells. Three among 5, 000 transformants screened formed clear zones around their colonies. From the functional clones, three recombinant plasmids (pMG11, pMG12 and pMG13) had been isolated, and they were identified to carry the same 4 kb HindIII fragment originated from B. stearothemzophilus which was responsible for the xylanase activity. pMGl3, however, had the foreign DNA of opposite orientation compared to the other two recombinant plasmids. This recombinant plasmid gave much lower xylanase activity. B. stearothermophilus was observed to produce at least three xylanase activities as evidenced by the PAGE-xylan zymogram. The xylanase from E. coli HB101/pMG12 was judged to correspond to the largest among the three B. stearothermophilus xylanases observed in the zymogrom. The enzyme hydrolyzed xylooligosaccharides larger than xylotriose and degraded xylan to produce xylobiose and xylotriose as major products. The xylanase was considered to have trans-xylosidase activity, too.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.3
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• pp.60-68
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• 2008

This work describes a re-configurable 10MS/s to 100MS/s, low-power 10b two-step pipeline ADC operating at a power supply from 0.5V to 1.2V. MOS transistors with a low-threshold voltage are employed partially in the input sampling switches and differential pair of the SHA and MDAC for a proper signal swing margin at a 0.5V supply. The integrated adjustable current reference optimizes the static and dynamic performance of amplifiers at 10b accuracy with a wide range of supply voltages. A signal-isolated layout improves the capacitor mismatch of the MDAC while a switched-bias power-reduction technique reduces the power dissipation of comparators in the flash ADCs. The prototype ADC in a 0.13um CMOS process demonstrates the measured DNL and INL within 0.35LSB and 0.49LSB. The ADC with an active die area of $0.98mm^2$ shows a maximum SNDR and SFDR of 56.0dB and 69.6dB, respectively, and a power consumption of 19.2mW at a nominal condition of 0.8V and 60MS/s.