• Phonetics and Speech Sciences
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• v.2 no.4
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• pp.67-74
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• 2010

The purpose of this study was to explore the cross-linguistic difference in the spectral movement pattern of American English and Korean vowels. Eight American vowels /a/, /e/, /$\varepsilon$/, /i/, /I/, /o/, /u/, and /$\mho$/, and five Korean vowels, /a/, /e/, /i/, /o/ and /u/ in a fricative-vowel environment produced by adult speakers of each language were analyzed. The spectral movement patterns of the first two formant frequency values were measured and analyzed. The results showed that Korean vowels had minimal spectral movement, both in F1 and F2 values, as compared to American English vowels. Moreover, no consistent direction of movement was found in the three corner Korean vowels, while American English vowels showed consistent direction of movement for each vowel of the same phonemic category.

• Bulletin of the Korean Chemical Society
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• v.15 no.12
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• pp.1038-1042
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• 1994

The amperometric responses of thiourea were studied in 0.1 M NaOH by flow injection analysis. D. C. amperometric and pulsed amperometric detection methods were applied for the determination of thiourea at novel metal electrodes such as Pt and Au. Triple-step potential waveforms were adopted in the pulsed amperometric detection. With an optimized pulsed waveform, the current for the oxidation of thiourea was examined with the variation of flow rate of carrier solution and with the change in the amount of sample injected. Gold working electrode turned out to be better in sensitivity and signal to noise ratio than Pt electrode in the pulsed amperometric detection of thiourea. Detection limit is estimated to be 5.33 ${\times}$ 10$^{-5}$ M with this detection method.

• Bulletin of the Korean Chemical Society
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• v.11 no.5
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• pp.386-390
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• 1990

Yttrium oxysulfide incoporated with europium has been prepared by direct heating the mixture of $Y_2O_3,\;Eu_2O_3,\;NaOH(or\;Na_2CO_3)$, and S. The reaction of the mixture at low temperatures and treatment at higher temperatures are studied. The formation of $Y_2O_2S$ is completed at lower temperature (ca. 500$^{\circ}C$) and incorporation of $Eu^{3+}$ into $Y_2O_2S$ lattice proceeds at higher temperature (above 1000$^{\circ}C$) along with crystal growth. Small amount of the unknown phase considered to be $Y_2O_2S_2$ is formed along with $Y_2O_2S$ in the temperature range from 400$^{\circ}C$ to 460$^{\circ}C$.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.6
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• pp.773-779
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• 1986

In this paper, we discuss fabrication and characteristics of the Vertical Double diffused MOS(VDMOS) transistor. The epi layers of starting wafers are 18~22\ulcorner in thickness and 8~12\ulcornercm in resistivity. The channel regions are defined through the self-aligned double diffusion process. The characteristics of the fabricated VDMOS are breakdown voltage of 240V, threshold voltage of 2V, on-resistance of 226\ulcornerand transconductance of 3x10**-3 mho.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.4
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• pp.347-355
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• 1986

The Sonakdong river is very important water source not only for agricultural water of Kimhae field but also for fishery water. Recently the middle and lower areas of the river have the tendency to be heavily contaminated by domestic sewage and agricultural chemicals. Fifty six water samples were collected from 8 stations from July to December in 1985 for the experiment (Fig. 1). To evaluate the water quality, pH, water temperature, electrical conductivity, chloride ion, nutrients ($NO^{-}_{2}-N,\;NO^{-}_{3}-N,\;NH^{+}_{4}-N,\;PO^{3-}_{4}-P,\;SiO_2-Si$), total coliform, fecal coliform, and fecal streptococcus were determined. Range and mean value of the samples were as follows; pH $6.3{\sim}9.4$, 7.91; water temperature $6.1{\sim}34.8^{\circ}C,\;23.88^{\circ}C$; electrical conductivity (from St. A to G) $1.575{\times}10^2{\sim}30.50{\times}10^2{\mu}{\mho}/cm,\;6.57{\times}10^2{\mu}{\mho}/cm$; chloride ion $23.5{\sim}14,300mg/l$, 770.0mg/l; nitrite-nitrogen $0.007{\sim}0.110mg/l$, 0.053mg/l; nitrate-nitrogen $0.001{\sim}1.638mg/l$, 0.649 mg/l; ammonia-nitrogen $0.017{\sim}4.200mg/l$, 0.497mg/l; phosphate-phoshorus $0.011{\sim}0.281mg/l$, 0.086mg/l; and silicate-silicious $2.4{\sim}6.5mg/l$, 4.43mg/l. Electrical conductivity and chloride ion of the station F(Chomanpo) were $2.676{\times}10^2{\mu}{\Omega}cm$ and 123.99mg/l which were lower than those of others. Among the analyzed nutrients, silicate-silicious concentration was the highest through all the samples. The bacterial density of the samples ranged $36{\sim}110,000/100ml$ for total coliform, $15{\sim}46,000/100ml$ for fecal coliform and $3.6{\sim}15,000/100ml$ for fecal streptococcus. The range and the mean of the TC/FC ratio were $3.0{\sim}9.6$, 5.51 and those of the FC/FS ratio were $1.1{\sim}9.2$, 6.19, respectively. On the other hand, fecal coliform was not detected in about $78\%$ of the water samples examined. Composition of coliform was $52\%$ Escherichia coli group, $3\%$ Citrobacter freundii group, $13\%$ Enterobacter aerogenes group and $31\%$ others.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.2
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• pp.152-157
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• 1991

Growth status, plant nutrition and soil chemical properties were investigated for lettuce, spring onion and red pepper grown under vinyl house near Yesan. Low Ca and Mg with high K in soil resulted in Ca deficiency with slight Mg insufficiency in Korean lettuce. In this soil pH was low and EC was extremely low. Spring onion(Allium wakegi) can not emerge or showed poor growth(50%) due to high EC(above 0.5m mho/cm) and low pH (below 6.2). Red pepper plant showed wilt disease probably due to low soil pH.

• Journal of Wetlands Research
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• v.4 no.1
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• pp.21-31
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• 2002

Vegetation structure and sediment properties were investigated in the Wondong wetland of the Nakdong-gang, Yangsan-city, Gyeongsangnam-do, Korea. The vegetation type was classified into eleven communities based on the actual vegetation map: Miscanthus sacchariflorus community, Salix nipponica community, Phragmites communis community, Zizania latiofolia community, Trapa japonica community, Hydrilla verticillata community, Hydrocharis dubia community, Digitaria sanguinalis community, Nelumbo nucifera community, Phragmites japonica community, and Salix matsudana for. tortuosa community. Among them, Distribution area of Miscanthus sacchariflorus community was largest as 12.4 ha (36.3%). The dominant vegetation type was Miscanthus sacchariflorus community based on phytosocialogical method, and it was classified into two subcommunities; Persicaria maackiana - Miscanthus sacchariflorus subcommunity and Hydrilla verticillata - Miscanthus sacchariflorus subcommunity. Ranges of the sediment properties such as pH, conductivity, organic matter, total nitrogen, and available phosphorus were 4.9~6.2, $23{\sim}423{\mu}mho/cm$, 0.37~11.16%, 0.02~0.36% and 0.14~0.38mg/100g, respectively. Percentages of the partical size of the sediment such as clay, silt, and sand were 5.0~27.0%, 6.7~31.3%, and 46.7~88.3%, respectively.

• Steel and Composite Structures
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• v.21 no.5
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• pp.1157-1182
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• 2016

A newly puzzle shape of crestbond rib shear connector is a type of ductile perfobond rib shear connector. This shear connector has some advantages, including relatively easy rebar installation and cutting, as well as the higher shear resistance strength. Thus, this study proposed a newly puzzle shape of crestbond rib with a "${\mho}$" shape, and its shear resistance behaviors and shear strengths were examined using push-out tests. Five main parameters were considered in the push-out specimens to evaluate the effects of shear resistance parameters such as the dimensions of the crestbond rib, transverse rebars in the crestbond dowel, concrete strength, rebar strength, and dowel action on the shear strength. The shear loading test results were used to compare the changes in the shear behaviors, failure modes, and shear strengths. It was found that the concrete strength and number of transverse rebars in the crestbond rib were significantly related to its shear resistance. After the initial bearing resistance behavior of the concrete dowel, a relative slip occurred in all the specimens. However, its rigid behavior to shear loading decreased the ductility of the shear connection. The cross-sectional area of the crestbond rib was also shown to have a minor effect on the shear resistance of the crestbond rib shear connector. The failure mechanism of the crestbond rib shear connector was complex, and included compression, shear, and tension. As a failure mode, a crack was initiated in the middle of the concrete slab in a vertical direction, and propagated with increasing shear load. Then, horizontal cracks occurred and propagated to the front and rear faces of the specimens. Based on the results of this study, a design shear strength equation was proposed and compared with previously suggested equations.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.7
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• pp.393-400
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• 2003

This paper discusses how to implement and verify a software model of the digital relay that can be added to real time digital simulator(RTDS) model library and is then subjected to the same outputs as the actual relay. The software model is stand-alone and can be used with real relays. It is also possible to conduct interactive real-time tests when the system effects of the relay action need to be investigated. The characteristics of mho type and the quadrilateral type, which is commonly used in recently developed relays, are modeled in this paper. Single circuit line and double circuit line system are used for model verification. The transmission lines are each 100 km in length and are modeled as distributed parameter lines but not frequency dependent. The transmission lines in the single circuit system are modeled as ideally transposed line. The mutual coupling data with the parallel line was taken account in the transmission lines for the double circuit system. The main CTs and PTs are included and operated in their linear region during the tests. For the purpose of testing the relay model accuracy the faults have been applied at various points on the protected line. Its accuracy is assessed against theoretical values.

• Journal of the Korean Electrochemical Society
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• v.15 no.3
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• pp.198-205
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• 2012

Carbon-supported manganese oxide composite were fabricated as an air cathode material for Li-air batteries by hydrothermal method. The composite materials of carbon and manganese oxide were investigated by the implementation of X-ray diffraction, FE-SEM and BET surface area measurer. The manganese oxide synthesized at $170^{\circ}C$ for 12 h has a rod like shape morphology with 40-50 nm long in size. A Lithium-air battery with coin type, of which electrodes are composed of cathode composite materials synthesized $170^{\circ}C$-12 h and lithium metal anode, reveals its first discharge capacity of 3,852 mAh/g and four discharge-charge cycles.