• Polymer(Korea)
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• v.29 no.2
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• pp.190-197
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• 2005

Nanocomposites of three different polyesters with dodecyltriphenylphosphonium-montmorillonite $(C_{12}PPh-MMT)$ as an organoclay are compared with their thermal properties, mechanical properties, and morphologies. Poly (butylene terephthalate) (PBT), poly(ethylene terephthalate) (PET), and poly(trimethylene terephthalate) (PTT) were used as matrix polymers in the fabrication of polyester nanocomposite fibers. The variations of their properties with organoclay content in the polymer matrix and draw ratio (DR) are discussed. Transmission electron microscopy (TEM) micrographs show that some of the clay layers are dispersed homogeneously within the polymer matrix on the nano-scale, although some clay particles are agglomerated. We also found that the addition of only a small amount of organoclay is enough to improve the thermal stabilities and mechanical properties of the polyester nanocomposite fibers. Even polymers with low organoclay contents $(<5\;wt\%)$ were found to exhibit much higher strength and modulus values than pure polyester fibers. In the cases of all polyester hybrid fibers, the values of the tensile mechanical properties were found to decrease linearly with increasing DR. However, the initial tensile modulus of the PTT hybrid fibers were found to be independent of DR.

• Journal of Oral Medicine and Pain
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• v.32 no.4
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• pp.413-419
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• 2007

The aims of this study were to investigate the relationships among several types of thermal pain thresholds, and pressure pain thresholds. This study was designed to examine whether there were associations among different types of pain thresholds, and among different recording sites for each pain threshold measurement. Pain sensitivity thresholds including cold pain threshold (CPT), heat pain threshold (HPT), heat pain tolerance threshold (PTT), and pressure pain threshold (PPT) of 56 subjects with symptoms of temporomandibular disorders were measured on temporal muscle, masseter muscle, TMJ, and tibial areas. Thermal pain thresholds including CPT, HPT, and PTT did not show any gender differences. However, women showed significantly lower PPTs than men on all recording sites. Three thermal pain thresholds including CPT, HPT, and PTT showed weak to high correlations on all the recording sites (r= 0.324 to 0.754, p<0.05). PPTs did not show any significant correlations between each thermal pain threshold. The pain threshold of each recording site showed weak to high correlations in all pain threshold measures (r= 0.284 to 0.878, p<0.05). Our study demonstrated that thermal pain thresholds, and pain tolerance thresholds were significantly correlated, but did not show any correlation between thermal pain thresholds and pressure pain thresholds. There were relatively high correlations among the pain thresholds of different recording sites.

• Food Science and Preservation
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• v.21 no.5
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• pp.727-734
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• 2014

To investigate anti-thrombosis and anti-oxidation activities of the root of Arctium lappa L (RALL), which has been used as foodstuff and oriental medicine in Korea, the ethanol extract and its subsequent organic solvent fractions of the RALL were prepared. The yield of ethanol extraction was 10.94%, and the content of total polyphenol and total sugar of ethanol extract were 5.01 and 694.53 mg/g, respectively. The fraction yields of n-hexane, ethylacetate (EA), butanol and water residue were 1.62, 0.42, 5.98 and 85.38%, respectively. In anticoagulation activity assay, the ethanol extract of RALL did not show significant changes in thrombin time (TT), prothrombin time (PT) and activated partial thromboplastin time (aPTT), whereas the EA fractions showed 13 folds extended TT, PT, and aPTT respectively. Interestingly, the water residue showed strong activation effect against blood clotting factors with shortened aPTT, which might provide the evidence of coagulation agent of RALL in folk remedy. In anti-platelet aggregation assay, the activity of the ethanol extract and its fractions were comparable to that of aspirin. Especially the EA fraction showed 2-folds higher inhibitory activity than aspirin. In anti-oxidation activity assay, the EA fraction also showed strong in DPPH, ABTS and nitrite scavenging activity, and reducing power activity. The extract and fractions of RALL have ignorable hemolytic activity against human RBC up to 0.5 mg/mL concentration. Our results suggest that the EA fraction of RALL have potentials as safe and novel anti-thrombosis agent.

• The Journal of the Acoustical Society of Korea
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• v.32 no.3
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• pp.262-268
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• 2013

The performances of speech compression schemes appeared to be dependent on the response profiles to compressed stimuli and the features of individual languages to some extent. Although these response profiles were critical in comparing various compression outcomes, the related data were limited in number for Korean monosyllabic words. From the previous study, data from PNT (Preserving No Trait) compression was selected as a base set for comparison. In this study, the outcomes from PPT (Preserving Pitch Trait) and PTT (Preserving Time Trait) were analyzed under the same condition. Then, the properties of these three widely used representative compression schemes were quantitatively compared in normal hearing adults (N=20) for controlled Korean quintet digit sets (0 through 9). Results showed that PPT compression scheme exhibited the best perceptual performances for the Korean quintet digit sets in the final outcomes (PPT>PTT>PNT). The compression ratios of 50% performances were estimated as about 20%, 42%, and 44% for PPT, PTT, and PNT, respectively. The data indicated the influences of the salient psychoacoustic features of the three representative compressions on perceiving Korean monosyllabic digit words. This controlled procedure with monosyllabic quintet sets can evaluate efficiency and effectiveness of other compression schemes and may also contribute to diagnosing auditory processing disorders and fitting special hearing aids with compression issues.

• Journal of Biomedical Engineering Research
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• v.25 no.6
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• pp.605-609
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• 2004

Blood pressure (BP) is one of the important physiological parameters for diagnosing cardiovascula diseases by means of noninvasive method. Existing noninvasive methods for measuring arterial BP have to use cuff and difficult in measuring arterial BP continuously. Systolic blood pressure (SBP) and pulse transit time (PTT) have a kind of inverse relationship. We acquired PTT data when subjects were in relaxation and also after exercise. We performed the linear regression analysis for making the regression equations for each subject and the regression equation for all subjects. We compared the estimated SBP with the measured SBP to check the accuracy of our regression equations. From the result, the regression equations for each subject was appropriate according to the American National Standards Institute of the Association of the Advancement of Medical Instrument (ANSI/AAMI) which says that BP devices should have ±5mmHg mean of error and 8mmHg standard deviation of error. However, the regression equation for all subjects was not proper to ANSI/AAMI recommendation. The result means that, without cuff, we can continuously estimate each subject's SBP through PTT and indivisual calibration.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.68-71
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• 2003

Poly(trimethylene terephthalate)는 1941년 Caligo printing Ink 사의 Whinfield와 Dickson에 의해 PET와 함께 처음으로 그 중합방법이 보고 된 이래, 주원료인 1,3-propanediol의 생산가격이 너무 높아 지난 60년간 상업화 및 학문적 연구가 거의 이루어져 있지 않다. 미국의 Shell사와 독일의 Degussa(미국의 Dupont)에 의해 1,3-propanediol이 대량 생산되면서[1], PTT 섬유의 상업적 생산에 점점 관심이 집중되고 있다. 국내에서도 S사와 Shell의 공동연구에 의해 제품이 생산되는 둥 많은 연구가 진행중에 있기는 하지만, Poly(ethylene terephthalate)의 연구에 비한다면 아직 걸음마 단계의 기초 자료로 제품이 생산되고 있는 실정이다. (중략)

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.341-342
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• 2003

Poly(trimethylene 2,6-naphthalate)(PTN)은 dimethyl-2,6-naphthalene dicarboxylate(NDC)와 1,3-propanediol(PDO)로 합성된 polyester이다. 비록 PTN은 아직 상업화된 resin은 아니지만 Poly(trimethylene terephthalate)(PTT)와 비슷한 화학적 구조를 가지며 PTT 보다 높은 유리전이 온도(72$^{\circ}C$)를 나타내고 있으므로 다양한 분야에 응용될 수 있다. 특히 최근에 1,3-propanediol based polyester는 가스 차탄 특성이 우수하다는 것이 보고되었으며 PTN의 산소, 이산화탄소 등 가스 차단 특성은 poly(ethylene 2,6-naphthalete)(PEN)보다 우수한 것으로 보고되었다. (중략)

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.419-420
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• 2003

PET 섬유는 굴절률이 1.64로서 다른 섬유에 비해 높고 표면이 매끄러우며 몰흡광계수가 낮은 분산염료로 염색되기 때문에 섬유표면에서 가시광선의 반사율이 커서 염색된 후에도 색이 진하게 보이지 않는 결점이 있다. PET 섬유의 심색화법으로는 염료가 쉽게 침투할 수 있게 구조를 변화시키거나, 섬유를 개질하여 흡광성이 우수한 염기성 염료 등으로 염색을 하는 방법, 섬유표면에 요철구조를 만들고 저굴절율의 수지피막을 형성시켜 빛의 표면반사를 줄여주는 방법 등이 가능한 것으로 알려져 있다. (중략)

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.363-366
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• 2002

Poly(trimethylene terephthalate)(이하 PTT)는 1941년 Caligo Printing Ink 사의 Whinfield와 Dickson에 의해 PET와 함께 처음으로 중합방법이 보고[1]되었으나, 원료인 1,3-propanediol의 제조가격이 너무 높아 지난 60년간 상업화 및 학문적 연구가 거의 이루어지지 않았다. 최근 미국의 Shell사와 독일의 Degussa(현재 미국의 duPont)에 의해 1,3-propanediol이 대량생산되면서 PTT섬유의 상업적 생산에 점점 관심이 집중되고 있다. (중략)

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.41-44
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• 2002

블렌딩이나 공중합체의 합성은 한가지 또는 모든 구성성분 고분자의 단점을 보완하면서 효과적인 물성 발현을 위해 연구되어 왔다. 특히 방향족 폴리에스테르계 고분자들 사이에서는 PET/PEN, PEN/PHN, PBT/PBN, 또는 PET/PBT 등의 공중합체가 보고되고 있다[1-3]. 한편, poly(trimethylene terephthalate)(PTT)는 최근 섬유로 방사되어 카펫, 의류 등으로 응용된 이후 PTT를 주성분으로 하는 bicomponent 멜트블로운 부직포[4], 염색[5] 등의 연구가 활발히 이루어지고 있다. (중략)