• 한국세라믹학회지
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• 제28권11호
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• pp.908-916
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• 1991

The characteristics of the carbonized and calcined products made from coal tar pitch coke and coal tar pitch, were investigated in the aspect of the manufacture of isotropic graphite with high density. The mesophase from the pitch was rapidly formed at higher heat-treatment temperature between 410$^{\circ}C$ and 450$^{\circ}C$, where the insolubes in the pitch accelerated the rate of nucleation and growth of the mesophase. The benzene insolubles and the quinoline insolubes were increased as the heat treatment temperature and the heat-treatment time increased. The ratio of benzene insolubles and quinoline solubles (BI/QS) was decreased as the heat-treatment temperature was higher and maintained to be nearly constant regardless of heat-treatment time at fixed heat treatment temperature. The bulk density of the calcined carbon was linearly proportional to the ratio of quinoline solubes to volatile matter in the green coke. Anisotropic ratio of electrical resistance was measured to be between 0.98 and 1.10.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1995년도 제12회 음성통신 및 신호처리 워크샵 논문집 (SCAS 12권 1호)
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• pp.123-126
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• 1995

The waveform coding are concerned with simply preserving the wave shape of speech signal through a redundancy reduction process. In the case of speech synthesis, the wave form coding with high quality are mainly used to the synthesis by analysis. However, because the parameters of this coding are not classified as either excitation and vocal tract parameters, it is difficult to applying the waveform coding to the synthesis by rule. In this paper, we proposed a new pitch alteration method that can change the pitch period in waveform coding by using scaling the time-axis and compensating the spectrum. This is a time-frequency domain method that is preserved in the phase components of the waveform and that has a little spectrum distortion with 2.5% and less for 50% pitch change.

• 말소리와 음성과학
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• 제4권1호
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• pp.55-65
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• 2012

In this study, the prosodic disambiguation of the syntactic attachment differences was investigated in relation to the effect of lexical bias. Speech materials were composed of N1-conj-N2-PP phrases such as "walkers and runners with dogs." The results show that the use of durational pattern is dominant over the pitch pattern to differentiate the attachment differences. The characteristic pitch contour was the rise and fall over N1 and N2 in the high attachment. The pitch contour in the low attachment was the rise and fall over N2 and N3 although the frequency of such patterns was lower for the low attachment case. For the durational pattern, the lengthening in the N2 region plays a significant role in the disambiguation of the syntactic attachments. The interaction between the lexical bias and the syntactic attachment was not statistically significant in the duration data.

• 음성과학
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• 제1권
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• pp.27-38
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• 1997

The differences in French Intonation between French and Korean learners can be applied to French intonation education. One native French speaker and three native Korean speakers who learned French language at High school were selected for this study. The subjects spoke test phrases based on the different syntactic structures. High-Speed speech Analysis system(RILP) was used for this experiment. The different intonation curves were showed at the end of phrase and at the beginning of phrase between French and Korean learners. At the end of phrases, French intonation appeared to have increasing and decending pitch contours in the case of wh-question, exclamation and finality. However, Korean learner's intonation showed only increasing pitch contours. At the beginning of phrase, French intonation shows decending pitch contours in the case of minor continuation and command. In contrast, Korean learner's intonation appeared to have increasing pitch contours. The new intonation training system using PC can have great effect on education of French as a second language.

• International Journal of Aeronautical and Space Sciences
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• 제9권1호
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• pp.66-75
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• 2008

In this work, we explore the feasibility of roll-pitch-yaw integrated autopilots for high angle-of-attack missiles. An investigation of the aerodynamic characteristics of a surface-to-air missile is presented, which reveals the strong effects of cross coupling between the longitudinal and lateral dynamics. Robust control techniques based on $H_{\infty}$ synthesis are employed to design roll-pitch-yaw integrated autopilots. The performance of the proposed roll-pitch-yaw integrated controller is tested in high-fidelity nonlinear five-degree-of-freedom simulations accounting for kinematic cross-coupling effects between the lateral and longitudinal channels. Against nonlinearity and cross-coupling effects of the missile dynamics, the integrated controller demonstrates superior performance when compared with the controller designed in a decoupled manner.

• 사상체질의학회지
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• 제18권3호
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• pp.75-93
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• 2006

1. Objectives and Methods Sasang Constitutional Medicine is the original Korean Medicine. The purpose of this study was to objectify the diagnosis of Sasang Constitution. 212 Women's sentences were analyzed into 228 factors like Pitch, APQ, Shimmer, Octave and Energy, etc. Women's sentences were classified into 3 categories: total group, under 54 years old group and over 55 years old group. 2. Results 1) In Total group Soyangin's Center feq.(3) was significantly high compared with Taeyangin and Taeumin groups. Taeumin's Pitch2 was significantly high compared with Soeumin and Taeyangin groups. Taeyangin's Pitch S.D. was significantly high compared with Soyangin group. Taeyangin's Octave6 was significantly high compared with Soeumin group. There were no significant differences among constitutional groups in APQ and Shimmer segment. On the point of Energy, Taeyangin's G Tot E(1), G# Tot E(1), G dev.(1), G# dev.(1), G Tot E(2), G# Tot E(2), G dev.(4) and G# dev.(4) were significantly high compared with other groups. Soyangin's A#S.D.(2) was significantly high compared with Taeyangin group. Taeyangin's A#S.D.(3) was significantly high compared with Taeumin group. Taeyangin's F S.D.(5), F# S.D.(5) and Max Average were significantly high compared with Soeumin group. Taeumin's Peak3 and Peak4 were significantly high compared with Taeyangin group. Taeumin's PeakValue1 was significantly high compared with Soeumin group. Taeyangin's PeakValue2 was significantly high compared with Soeumin group. Taeyangin's PeakValue3 and PeakValue5 were significantly high compared with Other groups. 2) In Under 54 years old group, there were no significant differences among constitutional groups in APQ, Shimmer and Octave segment. Taeumin's Center freq.(2) was significantly high compared with Taeyangin and Soyangin groups. Taeumin's Pitch(2) and Pitch(3) were significantly high compared with Taeyangin and Soeumin groups. Taeyangin's and Taeumin's Pitch S.D. were significantly high compared with Soyangin group. Taeyangin's and Soyangin's Octave2 were significantly high compared with Taeumin group. On the point of Energy, Taeyangin's and Soyangin's A# S.D.(2) were significantly high compared with Soeumin group. Taeyangin's and Soyangin's G# dev.(1), G# dev.(2) were significantly high compared with Taeumin group. Taeyangin's and Taeumin's F# S.D.(3) were significantly high compared with Soeumin group. Taeyangin's and Soyangin's Max Average were significantly high compared with Soeumin group. Taeumin's Peak3 was significantly high compared with Taeyangin and Soeumin groups. Taeyangin's and Taeumin's PeakValue2 were significantly high compared with Soeumin group. Taeyangin's and Soeumin's PeakValue3 were significantly high compared with Taeumin group. Taeyangin's and Soyangin's PeakValue5 were significantly high compared with Soeumin group. Taeyangin's and Soyangin's PeakValue9 were significantly high compared with Taeumin group 3) In Over 55 years old group, there were no significant differences among constitutional groups in Pitch, APQ, and Peak segment. Soeumin's F Shimmer(1) and F Shimmer(2) were significantly high compared with Taeyangin and Taeumin groups. Soeumin's G# Shimmer(1) and G# Shimmer(2) were significantly high compared with Soyangin group. Taeyangin's Octave5 and Octave6 were significantly high compared with Soeumin group. On the point of Energy, Soyangin's C S.D., F# S.D.(1), F# S.D.(2) and G dev.(2) were significantly high compared with other groups. Soyangin's F# S.D.(3) was significantly high compared with Taeumin and Soeumin groups. Taeyangin's and Taeumin's G# S.D.(2) and G# S.D.(3) were significantly high compared with Soyangin group 3. Conclusions From above result, there is the possibility of efficient standard guide for constitution diagnosis by analysis of voice

• Korean Chemical Engineering Research
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• 제58권1호
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• pp.142-149
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• 2020

본 연구에서는 인조흑연의 낮은 이론용량을 개선하기 위하여 음극소재로서 흑연/실리콘/피치 복합소재의 전기화학적 성능을 조사하였다. 구형의 인조 흑연 표면을 polyvinylpyrrolidone (PVP) 양친성 물질로 코팅한 후 실리카를 성장시켜 흑연/실리카 소재를 합성하였으며, 석유계 피치 코팅과 마그네슘 열 환원법을 통해 흑연/실리콘/피치 복합소재를 제조하였다. 흑연/실리콘/피치 복합소재의 전극은 poly(vinylidene fluoride) (PVDF), carboxymethyl cellulose (CMC), polyacrylic acid (PAA) 바인더에 따라 제조하였으며, 다양한 전해액과 첨가제를 이용하여 전지를 조립하였다. 흑연/실리콘/피치 복합소재는 X-ray diffraction (XRD), scanning electron microscope (SEM)와 thermogravimetric analyzer (TGA)를 통해 물리적 특성을 분석하였으며, 전기화학적 특성은 충 방전 사이클, 율속, 순환전압전류, 임피던스 테스트를 통해 조사하였다. 흑연/실리콘/피치 복합소재는 흑연 : 실리카 : 피치 = 1 : 4 : 8일 때 높은 사이클 안정성을 보였다. PAA 바인더를 사용하여 제조된 전극은 높은 용량과 안정성을 보였으며, EC:DMC:EMC 전해액을 사용하였을 때 719 mAh/g의 높은 초기 용량과 우수한 사이클 안정성 나타내었다. 또한 vinylene carbonate (VC) 첨가시에 2 C/0.1 C 일 때 77% 용량 유지율과 0.1 C/0.1 C 일 때 88% 용량 회복을 나타냄을 확인하였다.

• 한국세라믹학회지
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• 제34권9호
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• pp.963-968
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• 1997

Coal tar pitch was used to study the effect of the pyrolysis conditions to produce mesophase pitch used as a matrix precursor for carbon/carbon composites. The pyrolysis conditions were presented in all cases that the total pressure was 1 atm and the first stage temperature was changed from 25$0^{\circ}C$ to 34$0^{\circ}C$ to remove the low molecular weight compounds in the pitch, and then, heated to 40$0^{\circ}C$ to form anisotropic mesophase as the second stage temperature. The first stage temperature was very affected to form resulting anisotropic mesophase pitch. The resulting mesophase pitches show a significantly increased anisotropic contents upto 30$0^{\circ}C$. However, the contents of mesophase were decreased above 30$0^{\circ}C$. It was the reason that the first stage temperature had been control the number of free radicals to react the aromatic compounds in the pitch to form high molecular weight compound. Therefore, the two stage pyrolysis method could be very effectively used to control various contents of anisotropic polyaromatic mesophase compared to continuous to continuous heating method.

• Journal of Preventive Medicine and Public Health
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• 제30권1호
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• pp.145-155
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• 1997

Interview survey and dermatological examination have been performed to investigate the health problems of workers continuously exposed to coal-tar pitch. The phototoxicity of coal-tar pitch was confirmed by the photopatch tests for six healthy adults. The main results are followings; 1. There was no special history of allergic diseases in both the exposed and non-exposed group. 2. The frequency of the phototoxic dermatosis and the coal-tar acne in the exposed group was significantly greate.(p<0.05) than that of the control group. In the exposed group, the phototoxic dermatosis and the coal-tar acne were observed in nine workers(90%) and seven workers(70%), respectively. However, those, disease were not observed in the control group. 3. Five results(83%) were positive to the photopatch test for coal-ta. pitch 48 hours after UVA irradiation. But the lesion was subsiding 72 hours after UVA irradiation. 4. Malignant cancers were not reported among workers ever exposed to coal-tar pitch. In conclusion, it appears that workers exposed to coal-tar pitch have high risks of phototoxic dermatosis and coal-tar acne. A health policy should be provided to prevent phototoxic dermatosis among coal-tar pitch workers. More studies are required to determine malignancy.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.264-267
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• 2003

Pitch measurements of 150 nm pitch one-dimensional grating standards were carried out using an contact mode atomic force microscopy(C-AFM) with a high resolution three-axis laser interferometer. It was called as 'Nano-metrological AFM' In Nano-metrological AFM, Three laser interferometers were aligned well to the end of AFM tip. Laser sources of the three-axis laser interferometer in the nano-metrological AFM were calibrated with an I$_2$-stablilzed He-Ne laser at a wavelength of 633 nm. So, the Abbe error was minimized and the result of the pitch measurement using the nano-metrological AFM has a traceability to the length standard directly. The uncertainty in the pitch measurement was estimated in accordance with the Guide to the Expression of Uncertainty in Measurement(GUM). The Primary source of uncertainty in the pitch-measurements was derived from repeatability of pitch-measurement, and its value was approx 0.186 nm. Expanded uncertainty(k=2) of less than 5.23 nm was obtained. It is suggested that the metrological AFM is a useful tool for the nano-metrological standard calibration.