• Korean Journal of Materials Research
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• v.10 no.12
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• pp.838-844
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• 2000

For the fabrication of titanium diboride($TiB_2$)- based cermet as applications of cutting tools and wear resistant materials, a binder metal with good mechanical properties and sinterability is essential. In this study, SUS316L was chosen for the binder metal to obtain a new $TiB_2$ cermet with superior hardness and toughness.$TiB_2$-SUS316L cermets were densified to relative density of more than 99% by pressureless sintering at temperature above $1650^{\circ}C$ The flexural strength was up to 1290MPa at 10vo1%SUS316L cermet in spite of the formation of $Fe_2$B phase during the sintering. The fracture toughness was obtained up to $6MPam^{1/2}$ with Victors hardness over 18Gpa. These hardness and fracture toughness combinations are better than those of conventional cermet. The high temperature strength remarkably decreased by the plastic deformations of SUS316L binder phase at nearby $800^{\circ}C$ .

• Food Science and Preservation
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• v.24 no.7
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• pp.965-974
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• 2017

This study was carried out to investigate the effect of particle size of naked oat flour (NOF) on physicochemical property and antioxidant activity. The NOF was passed through $250{\mu}m$ and $160{\mu}m$ size sieves to obtain three fractions (fraction A: $250{\mu}m$ or more, fraction B: $160-250{\mu}m$, and fraction C: $160{\mu}m$ or less). Moisture, crude protein, crude fat, and crude ash contents of NOF were 8.4, 15.7, 10.0, and 1.8%, respectively, and these contents were increased as the particle size of NOF decreased. The mineral and free amino acid contents of NOF also had a similar tendency. The contents of total starch, amylose, starch damage, total dietary fiber, ${\beta}$-glucan, total phenolics, and flavonoids in NOF were 56.4%, 21.4%, 11.7%, 11.0%, 4.7%, $237.8{\mu}g/g$ and $90.9{\mu}g/g$, respectively. As the particle size of NOF decreased, total starch, amylose, and starch damage contents increased, whereas total dietary fiber, ${\beta}$-glucan, total phenolic and flavonoid contents decreased. Also, three antioxidant activities of NOF were closely correlated with their total phenolics and flavonoids contents, showing high correlation coefficient values ($R^2=0.87$ and 0.81, respectively).

• Journal of the Korean Mathematical Society
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• v.41 no.4
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• pp.617-627
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• 2004

Let (equation omitted) denote the class of bounded linear Hilbert space operators with the property that $\midA^2\mid\geq\midA\mid^2$. In this paper we show that (equation omitted)-operators are finitely ascensive and that, for non-zero operators A and B, A (equation omitted) B is in (equation omitted) if and only if A and B are in (equation omitted). Also, it is shown that if A is an operator such that p(A) is in (equation omitted) for a non-trivial polynomial p, then Weyl's theorem holds for f(A), where f is a function analytic on an open neighborhood of the spectrum of A.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.2
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• pp.1-8
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• 1990

The unequal bit-error control of rate r=b/n binary convolutional code is analyzed. The error protection afforded to each digit of the viterbi decoded b-tuple information word can be different from that afforded to other digit. The property of the unequal protection can be applied for improvement of SNR in transmitting sampled data of DPCM system.

• Journal of the Optical Society of Korea
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• v.11 no.2
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• pp.51-54
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• 2007

A holographic demultiplexer aimed at producing low polarization dependence loss using a long period volumetric diffraction grating inside photopolymer has been reported and experimentally demonstrated. To obtain the long period gratings, two kinds of gratings are recorded by angle of $4^{\circ}\;and\;6^{\circ}$ corresponding to the polarization dependence property of below 0.5 dB. From the experimental results, we demonstrate the 0.8 nm-spaced 21 channel holographic demultiplexer with the polarization dependence loss of less than -0.38 dB, the channel uniformity of 0.495 dB, and the channel crosstalk of -13 dB.

• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3338-3342
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• 2012

Covalent functionalization of a $B_{12}N_{12}$ nano-cage with $CO_2$ molecule has been investigated using density functional theory in terms of energetic, geometric, and electronic property analyses. Results show that besides two physisorption configurations, $CO_2$ preferably tends to perform [2+2] addition on B-N bonds of the cluster which are shared between six-membered and four-membered rings, releasing energy of 14.99 kcal/mol for adsorption of the first $CO_2$ and of 15.45 kcal/mol for the second one (per each molecule). On the basis of calculated density of states, we have found that the electronic properties of the physisorbed $B_{12}N_{12}$ by $CO_2$ have not changed, while slight changes have been predicted in the functionalized cases. Present results might be helpful to provide an effective way to modify the $B_{12}N_{12}$ properties for further purifications and applications.

• Journal of the Korean Ceramic Society
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• v.28 no.5
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• pp.415-421
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• 1991

Influence of Li2O.4B2O3 frit addition on the microstructure and thermal expansion properties of $\beta$-eucryptite ceramics was studied. With 1.0~10.0wt% frit addition, sintering temperature range was enlarged and densified body was obtained. Thermal expansion was increased from -6.67$\times$10-6 $^{\circ}C$-1 of pure sintered body to 1.03$\times$10-6$^{\circ}C$-1 of 6 wt% added body, but this increasement was accompanied by inhibition of thermal expansion anisotropy, so that improved microcracking property.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.7
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• pp.546-551
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• 1998

$Mn{1-X}Fe{2+X}O_4, Mg_{1-X}Fe_{2+X}O_4$ (x=0.0, 0.025, 0.1, 0.2) for negative temperature coefficient (NTC) thermistor was prepared by calcination at $800^{\circ}C$ and sintering at form 1100 to $1250^{\circ}C$ with $50^{\circ}C$ intervals. The best linear property was obtained in the Mn-based sample sintered at $1200^{\circ}C$ with x=0.0 composition. Temperature coefficient of resistance, $\alpha$, was $-5.6%/^{\circ}C$ in the Mn-based sample, $-5.2%/^{\circ}C$ in the MM-based sample, and $-1.6%/^{\circ}C$ in the Mg-based sample. thermistor parameter, B, was in the range of 2665~7780 K. The results show the possibility that Mn-Ni-Co based thermistor could be substituted by the composition used in this study.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.407-410
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• 2000

(M $n_{l-x}$M $g_{l-x}$)F $e_{2+x}$ $O_4$(x=0.0, 0.025, 0.1, 0.2) for NTC(negative temperature coefficient) thermistor was prepared by calcining at 80$0^{\circ}C$ and sintering at from 1100 to 130$0^{\circ}C$ with 5$0^{\circ}C$ intervals while x was varied from 0.0 to 0.025, 0.1 and 0.2. The best linear property was obtained in the based specimen sintered at 120$0^{\circ}C$ with x=0.1 composition. Thermistor parameter, $B_{25~85^{\circ}C}$, was in the range of 5000~ 7300 [K]. Temperature coefficient of resistance, $\alpha$$_{25^{\circ}C}$, was -5.2 %/$^{\circ}C$. The results showed the possibility that Mn-Ni-Co based thermistor could be substituted by the composition used in this study was confirmed.med.d.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.995-997
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• 1998

The experimental optical cross-connect based on delivery and coupling switch features all-optical property. It consists of erbium-doped fiber amplifiers, arrayedwaveguide gratings, optical switches and optical combiners. In 4 channel wavelength division multiplexing with 1.6 nm spacing, the difference in power level among channels for output signals from the optical cross-connect was within 2 dB.