• Carbon letters
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• v.25
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• pp.78-83
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• 2018

Pyrolyzed fuel oil (PFO) and coal tar was blended in the feedstock to produce pitch via thermal reaction. The blended feedstock and produced pitch were characterized to investigate the effect of the blending ratio. In the feedstock analysis, coal tar exhibited a distinct distribution in its boiling point related to the number of aromatic rings and showed higher Conradson carbon residue and aromaticity values of 26.6% and 0.67%, respectively, compared with PFO. The pitch yield changed with the blending ratio, while the softening point of the produced pitch was determined by the PFO ratio in the blends. On the other hand, the carbon yield increased with increasing coal tar ratio in the blends. This phenomenon indicated that the formation of aliphatic bridges in PFO may occur during the thermal reaction, resulting in an increased softening point. In addition, it was confirmed that the molecular weight distribution of the produced pitch was associated with the predominant feedstock in the blend.

• Speech Sciences
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• v.13 no.1
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• pp.55-66
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• 2006

A purpose of this study is to investigate the acoustic characteristics of English stress produced by the two groups of South Kyungsang (henceforth, SK) Korean speakers: high-proficiency and low-proficiency with reference to English native speakers. Another purpose is to compare results from the high- and low-proficiency SK Korean subjects with those of the native speakers, and to provide an analytical account of how approximate the high-proficiency SK Korean subjects' production is to the native speakers' and how different the low-proficiency SK Korean subjects' is from the native speakers'. Results indicated that the native speakers' main strategy used in producing stressed syllables was duration while the high-proficiency SK Korean subjects' was predominantly pitch-oriented. The low-proficiency SK Korean subjects' pitch patterns showed regularity, emphasizing the penultimate syllable with pitch. In comparing duration among the three groups, both groups of the SK Korean subjects became more even in their duration values for each syllable as the structure of the word or the sentence became more complex.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.356-359
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• 2007

Continuing improvements in integrated circuit chip density and functionality have mostly contributed toward a very large-scale integrated circuit(VLSI) and display device. In order to test (pass or fail) all of the high integrated semiconductor chip and display device, fine pitch probes are used. Fine pitch probes are manufactured by electroforming process of a Ni alloy in an electrolytic bath. In this paper, we expect that the electric field in bath with the Finite Element Method and applying the FEM result. So, we can obtained the probes that have high aspect ratio of 10 : 1

• Phonetics and Speech Sciences
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• v.6 no.4
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• pp.53-65
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• 2014

The current research examines whether pitch contour shapes in North Kyungsang pitch accent contrasts provide a phonetic dimension for phonological discreteness in a mimicry task. Two pitch accent continua resynthesized were created for HH vs. HL and HH vs. LH. To confirm a phonetic dimension for accounting for pitch accent categories in North Kyungsang Korean, the mimicries of speakers of two dialects (i.e., North Kyungsang & South Cholla) were compared. One of the findings showed that, for North Kyungsang speakers, the range of mean f0 peak times was a phonetic dimension undergoing a continuous shift within a stimulus continuum for both HH vs. HL and HH vs. LH. On the other hand, for South Cholla speakers, there were no apparent shifts around categorical boundaries for either HH vs. HL or HH vs. LH. Regarding individual mimicries on f0 peak timing, there are many variations. For HH vs. LH, three North Kyungsang speakers showed a discrete pattern reflecting a shift in phonological categories, but for HH vs. HL, there was no such distinction showing a categorical shift, though there were statistically significant differences for two speakers. Interestingly, one of the North Kyungsang speakers showed a continuous phonetic dimension for both HH vs. HL and HH vs. LH. Lastly, the f0 valley timing did not exhibit a discrete or gradient phonetic dimension for speakers of either dialect. On the basis of these results, what is interesting is that the tonal target such as high tone in North Kyungsang pitch accent categories within the autosegmental-metrical (AM) theory may be realized within individual cognitive systems for representing the interaction of perception and production.

• Journal of the Korean Ceramic Society
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• v.35 no.9
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• pp.974-980
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• 1998

This study is concerned with the production of carbon fiber reinforced carbon(C/C) with polyaromatic mesophase pitch as matrix precursor and with the investigation of friction-wear characteristics in ambient air using a constant speed type of friction tester. The main problem in using the polyaromatic mesophase as the matrix precursor is the high viscosity which may limit the complete impregnation of the fiber preform in the vacuum. To solve these problems two dimensional carbon fiber fabrics were infiltrated with meso-phase pitch in the pitch impregnator. After the impregnation and the heat treatment process. C/C com-posites were characterized by density porosity to monitor the influence of high pressure and temperature. It showed that the bulk density was increased and the apparent porosity and the density increasing rate was reduced as repeating the impregnation the carbonization and the heat treatment. The friction-wear charac-teristics of C/C composites were investigated by measuring the average friction coefficient and the specific wear rate as functions friction speed and friction pressure using a constant speed type of friction tester. C/C composite4s showed the average friction coefficient to be reduced as increasing the friction speed and the friction pressure.

• Speech Sciences
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• v.10 no.3
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• pp.187-209
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• 2003

In this paper, we examine if the lexical information of the verb and its noun object affects the pitch accent patterns of the verb phrase focus. Three types of verb-object combinations with different semantic weights are discussed: when the verbs have optional direct objects, when the objects have the greater semantic weight relative to verbs, and when the verbs and the objects have equal semantic weight. Argument-structure-based works note that the pitch accent location in a focused phrase is closely related to the argument structure and contextual information. For example, it has been argued that contextually new noun objects receive accent while given noun objects don't. Contrary to nouns, verbs can be accented or not in verb phrase focus regardless of whether they are given information or new information (Selkirk 1984, 1992). However, the production experiment in this paper shows that the accenting of verbs is not fully optional, but influenced by the lexical semantic information of the verbs. The accenting of noun objects with given information is possible and the deaccenting of new noun objects also occurs depending on the lexical information of the noun objects. The results demonstrate that in addition to argument structure and information by means of context sentences, the lexical semantic information of words influences the pitch accent location in focused phrase.

• Speech Sciences
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• v.15 no.3
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• pp.145-156
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• 2008

The goal of this study was to investigate acoustic and physiologic characteristics of two phonation types of 'Khoomei' which is a traditional singing style of people who live around the Altai mountains or Mongolia region. It can be produced two pitches simultaneously - high melody pitch can be perceived along with a low drone pitch. Sygyt and kargyraa styles are the most popular and identifiable styles and they can be recognized as the different sounds depending on the method of voice production. Two trained Mongolians participated and have used at least 5 - 6 years. The characteristics of this voice production were measured by using flexible fiberscope, Stroboscopy, Lx Speech studio, Spead, and Doctor Speech. In Sygyt style, very high vocal fold closure (71.50%) with both true and false vocal folds contact and strong breathing support was observed. They also showed that tongue height and harmonics were increased (around 10dB) with resonance cavity movement. In contrast, it was found that Kargyraa sound had very low pitch with relaxed stomach, less laryngeal tension and lower vocal fold contact (69.50%) than hard Sygyt style sound without raising the tongue during phonation. 'Khoomei' phonation can be made by strong contact of both true and false vocal folds and by increasing the harmonics as well.

• Proceedings of the KSLP Conference
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• 2003.11a
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• pp.144-145
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• 2003

고심도의 청각장애를 가진 아동의 음성은 높은 음도와 강도, 과비음 등 건청 아동과는 매우 다른 특성을 나타낸다. 그 중에서 초분절적인 요소에 속하는 억양은 청각장애 아동의 경우 단조롭고 높낮이 변화가 크지 않아서 의미전달에 어려움을 주는 중요한 요소이다. 청력손실이 고심도인 경우 수술을 하게 되면 청각적 수용능력을 높일 수 있어, 최근 부각되고 있는 인공 와우 이식수술을 받은 아동 또한 이러한 억양에서의 문제는 완전히 해결 받지 못하고 있다. 따라서 이 연구에서는 인공 와우 이식수술을 받은 청각장애 아동이 건청 아동과 억양에서 어떠한 차이를 드러내는지에 대해 알아보고자 하였다. (중략)

• Speech Sciences
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• v.4 no.1
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• pp.35-46
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• 1998

In this paper production and perception data were examined to discover what acoustic features are used in distinguishing wh-questions and yes/no-questions. Production data show that the two question types are distinguished by different accentual phrasing, pitch ranges in wh-phrases, and initial lenis stop voicing of the first syllable in verb phrases. Perception data by synthetic intonation show that the two question types are distinguished by the width of pitch ranges between the first and the second syllable in wh-phrases. Initial lenis stop voicing of the first syllable in verb phrases produces a strong effect on the perceptual discrimination of the two question types.

• Phonetics and Speech Sciences
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• v.5 no.4
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• pp.121-128
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• 2013

In Korean, wh-question and indefinite yes-no questions have the same morphemic and syntactic structure. In speech, however, these two types of questions are distinguished by a prosodic difference. In this study, we examined if Chinese Korean leaners can distinguish between these two types of questions in production and if they can correctly perceive the different meaning of a question based on the prosodic information. For this purpose, we analysed two types of interrogative sentences produced by 5 native speakers and 15 Chinese Korean language leaners. The results show that the 5 Korean native speakers produce two types of questions by a salient prosodic difference, i.e., difference of prosodic structure, different pitch range of wh-phrase and indefinite phrase, and different boundary tone. However, for the 15 Chinese speakers, the two types of questions were not distinguished by the same prosodic features but in the perception analysis they were able to distinguish between the two types of questions easily.