• Phonetics and Speech Sciences
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• v.6 no.2
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• pp.55-64
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• 2014

This study measured formant bandwidths of profound hearing impaired children and examined the characteristics of their articulation. For this study, 10 cochlear implanted children(CI), 10 hearing aid children(HA) and 10 normal hearing children(NH) were asked to read 7 Korean vowels(/ɑ, ʌ, o, u, ɯ, i, ɛ/). The subjects' readings were recorded by NasalView and analyzed by Praat. The analysis of the formant bandwidths explains the degree of vocal fold opening and the characteristics of radiation. Through the analysis of formant bandwidth, we can see that the hearing-impaired maintain vocal fold tension when they speak high vowels and characteristics of radiation. Narrower B1 means better maintain vocal fold tension, wider B2 means more front and wider B3 means the rounder lips. CI's B1 was widest and NH's was narrowest. And females' B1 was wider than males'. Among vowels, B1 of /a/ was widest, and B1 of /i/ was narrowest. In the case of B2, HA and NH's B2 was wider than CI's. Females' B2 was wider than males'. And B2 of /i/ was widest, and B2 of /ʌ/ was narrowest. In the case of B3, NH's was widest, and CI's was narrowest. Males' was wider than females'. Among vowels, B3 of /o/ was widest, and B3 of /ɛ/ was narrowest. As a result, first, through the analysis of B1, we can find that NH and males could better maintain vocal fold tension than the hearing-impaired or females, and all children articulate /i/ with vocal fold tension than other vowels. Second, through the analysis of B2, NH and HA articulate vowels with the weaker rounded than CI does. And females articulate vowels with the weaker rounded than males do. Third, through the analysis of B3, NH articulate vowels with the rounder than HA or CI do, and males articulate vowels with the rounder than females do. Through the results, we can expect that the analysis of formant bandwidth will be applied to the therapy of articulation for the hearing-impaired with hearing aids or cochlear implant.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.12
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• pp.1300-1310
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• 2003

In this paper, the performance of a multicarrier CDMA system using adaptive modulation and adaptive subchannel allocation scheme is analyzed in Rayleigh fading channel. The proposed adaptive modulator consists of modulation schemes using QPSK 16 QAM, 64 QAM and 256 QAM and constellations are pointed by Gray code. In addition, the threshold of the analysis is average E$\_$b//N$\_$o/ when the BER is 1 %. In the multicarrier system with adaptive subchannel allocation scheme, each DS waveform of user is transmitted over the K subchannels with the biggest fading among L subchannels. In case of the proposed system, total 4 subchannels are used and data are transmitted over 2 subchannels with the biggest fading, which results in the threshold of each channels is 5.2 dB, 9 dB, 13.2 dB and 8.4 dB, 12.2 dB, 16.3 dB. In the case of proposed system, the BER of 10$\^$-3/ is satisfied if average E$\_$b//N$\_$o/ is 8.1 dB. This is increased performance of 12.9 dB in comparison with conventional system. The BPS according to average channel is needed average E$\_$b//N$\_$o/ of about 15 dB in 7 bit. In the case of subchannel error, the BER of 10$\^$-3/ is 13.6 dB and is declined about 5.5 dB.

• Journal of Magnetics
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• v.9 no.2
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• pp.27-33
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• 2004

Magnetic properties of $Nd_4Fe_{77.5}B_{18.5}$ compound in term of exchange coupling between $Nd_2Fe_{14}B$ and $Fe_3B$ magnetic nano crystals in melt spun powders were characterized by varying the quenching speed in mass production line. The exchange coupled phenomenon was characterized as functions of nano crystal size and volume fraction of each magnetic phase which was possible by employing Henkel plot (${\delta}M$) and refined Mossbauer spectroscopy. The optimized magnetic properties obtained from the present volume production line were: $B_r= 11.73 kG,{_i}H_c/ = 3.082 kOe$, and $(BH)_{max} = 12.28 MGOe.$ The volume fraction of each magnetic phase for those conditions giving the grain size of 10 nm were ${\alpha}-Fe; 4.2%, Fe_3B; 60.1 %$, and $Nd_2Fe_{14}B; 35.7%$. The superior magnetic properties in the $Nd_2Fe_{14}Fe_3B$ based nanocomposites were confirmed to be dependant on the volume fraction of $Fe_3B$.

• Journal of the Korean Chemical Society
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• v.47 no.6
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• pp.591-596
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• 2003

Aminothienopyridazines 1a, b and aminothienocoumarin 2 condensed with DMFDMA to yield amidines 3a, b and 4. These compounds reacted with N-phenylmaleimide to yield 9 and 10. On the other hand reacting 3a, b, 4, 18, 19 and 20 with maleic anhydride afforded only the formylated derivatives 5a, b, 6, 21, 22 and 23 respectively. The reaction of 3a, b with diethyl fumarate afforded 11, formed most likely via hydrolysis of the amidine 14 during working up the reaction mixture. Irradiation of N-phenylmaleimide in microwave oven afforded [2+2] and [2+2+2] cycloaddition product.

• Journal of the Korean Chemical Society
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• v.55 no.1
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• pp.7-13
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• 2011

As an aid towards improving the treatment of exchange and correlation effects in electronic structure calculations, it is desirable to have a clear picture of concepts of exchange-correlation functionals in computational calculations. For achieving this aim, it is necessary to perform different theoretical methods for many groups of materials. We have performed hybrid density functional theory (DFT) methods to investigate the density charges of atoms in rings and cages of carbon nanotube. DFT methods are engaged and compared their results. We have also been inclined to see the impression of exchange and correlation on nuclearnuclear energy and electron-nuclear energy and kinetic energy. With due attention to existence methods, B3P86, B3PW91, B1B96, BLYP and B3LYP have used in this work.

• The Korean Journal of Food And Nutrition
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• v.7 no.2
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• pp.95-99
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• 1994

In order to investigate the fatty acid composition of Korean pumpkins, this study was designed. Three samples of Korean pumpkins, A(yellowish ripe), B(unripe, 30 days old) and C(unripe, 20 days old) were used for fatty acid analysis by gas chromatography. The results were as follows : Pumkin C, B and A showed 10, 12 and 15 kinds of fatty acids, respectively. In case of palmitic acid(C16:0), pumpkin C, B and A showed 22.5%, 22.9% and 26.6%, respectively. In case of u linolenic acid(C18:3), pumpkin C, B and A showed 22.6%, 23.6% and 44.8%, respectively. In case of palmitoleic acid(Cl6:1), pumpkin C. B and A showed 12.4%, 10.1% and 0.5%, respectively. In case of oleic acid(C18:1), pumpkin C. B and A showed 9.2%, 7.7% and 2.8%, respectively, In case of stearic acid(C18:0), pumpkin C, B and A showed B.S%, 3.7% and 3.5%, respectively. The ratio of P/S was 1.4, 1.6 and 1.9 for sample C, B and A, respectively. The ratio of w-3/w-6 was 1.1, 0.9 and 2.6 for sample C, B and A, respectively. Through this study, the ripe pumpkin(sample A) was thought to be good enough in nutritional aspects of fatty acids, particularly a-linoleic acid, Cl8 : 3(u-3) series.

• Proceedings of the Korean Ceranic Society Conference
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• 2000.10a
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• pp.70.1-70
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• 2000

• Kyungpook Mathematical Journal
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• v.53 no.3
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• pp.341-348
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• 2013

In this paper, the concept of supra $b$-irresolute maps is introduced and several properties of it is investigated. Furthermore, the notion of supra $b$-connectedness is defined and researched by means of supra $b$-separated sets.

• Korean Journal of Food Science and Technology
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• v.42 no.3
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• pp.361-367
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• 2010

Bacterial contamination of cooked rice was analyzed to evaluate the microbial safety. Thirty raw rice samples were collected in Korea and cooked in an electric rice cooker. Mesophilic aerobe, food-poisoning Bacillus cereus group, and their toxin genes were determined on cooked rice. The percentage of total mesophilic aerobe based on 1-3 log CFU/g was 27% among the samples. Bacillus spp. in MYP selective medium was similar to the number of mesophilic aerobe, whileas Bacillus spp. was detected in most samples after enrichment. Thirty-seven isolates from 30 cooked rices were identified as B. thuringiensis, B. cereus, B. valismortis, B. pumilus, B. coagulans, B. licheniformis, Geobacillus stearothermophilus, and Brevibacillus laterosporus. Twenty isolates (54%), more than half of the isolates, were B. thuringiensis while nine (27%) were identified as B. cereus. All B. thuringiensis isolates possessed non-hemolytic toxin genes and interestingly, seven B. cereus among nine isolates possessed emetic toxin genes. More B. thuringiensis was present on the cooked rice than B. cereus and most B. cereus possessed emetic toxin genes rather than diarrheal toxin genes. Therefore, food-borne outbreak due to B.cereus on the cooked rice kept at room temperature might be examples of emetic food-poisoning.

• Membrane Journal
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• v.19 no.3
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• pp.228-236
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• 2009

ABA type triblock copolymer of poly(hydroxyl ethyl acrylate )-b-polystyrene-b-poly(hydroxyl ethyl acrylate), i.e. PHEA-b-PS-b-PHEA, was synthesized throughatom transfer radical polymerization (ATRP). This block copolymer was thermally crosslinked with 4,5-imidazole dicarboxylic acid (IDA) via the esterification between the -OH groups of PHEA in block copolymer and the -COOH groups of IDA. Upon doping with ${H_3}{PO_4}$ to form imidazole-${H_3}{PO_4}$ complexes, the proton conductivity of membranes continuously increased with increasing ${H_3}{PO_4}$ content. The PHEA-b-PS-b-PHEA/IDA/${H_3}{PO_4}$ polymer membrane with [HEA]:[IDA]:[${H_3}{PO_4}$]=3:4:4 exhibited a maximum proton conductivity of 0.01 S/cm at $100^{\circ}C$ under anhydrous conditions. Thermal gravimetric analysis (TGA) shows that the PHEA-b-PS-b-PHEA/IDA/${H_3}{PO_4}$ complex membranes were thermally stable up to $350^{\circ}C$, indicating their applicability in fuel cells.