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Crystallization Behavior of poly(trimethylene terephthalate) in a Confined Geometry (제한공간에서의 폴리(트리메틸렌 테레프탈레이트)의 결정화 거동)

  • 임정은;이종관;이광희
    • Polymer Korea
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    • v.27 no.4
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    • pp.293-298
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    • 2003
  • The development of the crystalline structure of poly(trimethylene terephthalate) (PTT) in a confined geometry was investigated with optical microscope, small angle light scattering, and X-ray diffraction. The rejected distance, which was represented in terms of the parameter $\delta$, played an important role in determining the morphological patterns of poly (ethylene terethphalate) (PET/PTT) blend. In case of stepwise crystallization, the crystallization of PTT commenced in the interspherulitic region between the grown PET crystals and proceeded until the interspherulitic space was filled with the PTT crystals. The spherulitic surface of the PET crtstals acted as the nucleation sites where the PTT molecules preferentially crystallized, leading to the formation of transcrystalline structure. As a result, a mixed morphological pattern was observed in the PTT-rich phase: one was a typical spherulitic texture and the other was a transcrystalline texture. Some of the molecular conformations of PTT, which could adopt in the absence of the space limitation, were probably forbidden in the interlamellar and/or interfibrillar regions of the PET spherulite. This constraint was responsible for difference in the crystallization and melting behavior of PTT between the intra and interspheulitic regions of PET.

Dyeability Improvement of Polypropylene Fibers by Poly(trimethylene terephthalate) Blending (I) -Preparation and Thermal Properties of PP/PTT Blend Films- (Poly(trimethylene terephthalate) 혼합에 의한 폴리프로필렌 섬유의 염색성 개선 (I) -PP/PTT 블렌드 필름의 제조 및 열적 특성-)

  • Park, Kyung-Chul;Ham, Myong-Jo;Kim, Young-Ho
    • Textile Science and Engineering
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    • v.47 no.3
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    • pp.198-204
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    • 2010
  • To improve the dyeability of polypropylene (PP) fibers, PP/poly(trimethylene terephthalate) (PTT) blend fibers with various PTT contents were prepared using a commercial pilot spinning apparatus. The PP/PTT blend fibers were melt-pressed at $260^{\circ}C$ and quenched in ice-water to form PP/PTT blend films, and the thermal properties of the blend films were analyzed. DSC analysis showed that the melting temperature of the PP in the blends was unaffected by PTT blending and that PP and PTT crystallized independently. However, the melt crystallization temperature ($T_{mc}$) increased slightly with increasing the PTT content in PP/PTT blends. Synchrotron WAXS analysis of the annealed PP/PTT blend films showed that the crystal structure of PP in the blend films was the $\alpha$-form irrespective of the presence of PTT. SEM showed that PTT existed as spherical particles in the PP/PTT blends and that the particle size increased with increasing PTT content, which indicates that PTT was immiscible with PP. This immiscibility helped enhance the dyeing properties of the blend PP fibers.

Respiratory Effort Monitoring Using Pulse Transit Time in Human (인체에서 맥파전달시간을 이용한 호흡노력 모니터링)

  • 정동근
    • Journal of Biomedical Engineering Research
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    • v.23 no.6
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    • pp.485-489
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    • 2002
  • In this study. respiratory efforts were monitored by the change of pulse transit time (PTT) which is related with the arterial pressure PTT is the time interval between the peak of R wave in ECG and the maximal slope point of photoplethysmogram(PPG). Biosignals, ECG and finger photoplethysmogram(PPG), were converted to digital data, and PTT was evaluated in personal computer with every heart beat. Results were presented as a graph using spline interpolation. The software was implemented in C$\^$++/ as a window-based application program. PTT was periodically changed according to airflow in resting respiration. In the resting respiration, PTT was changed according to the respiratory cycle. The amplitude of PTT fluctuation was increased by deep respiration, and increased by partial airway obstruction. These results suggest that PTT is responsible to respiratory effort which could be evaluated by the pattern of PTT change. And it is expected that PTT could be applied in the monitoring of respiratory effort by noninvasive methods, and is very useful method for the evaluation of respiratory distress.

PTT Service Interworking Between IMS Based Networks and P2P Overlay Networks

  • Tieu, Tuan-Hao;Kim, Younghan;Gim, Gwangyong
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.7 no.7
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    • pp.1638-1656
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    • 2013
  • The demand for multimedia streaming services is increasing rapidly. To meet this demand, there has been much research and many practical developments for providing multimedia services. A push-to-talk (PTT) service is one of the multimedia streaming services that have been deployed not only over IP multimedia subsystem (IMS) but also in peer-to-peer (P2P) overlay networks. The benefit of PTT has been demonstrated in the literature. However, the need for using PTT service in communication can be arbitrary among users, regardless what kind of PTT services they use. This demand does not support current PTT systems, so an expansion of PTT services still be limited. Moreover, the combination of PTT services in IMS and P2P networks will help operators to provide more scalable PTT services. Therefore, in this paper, we proposed a model to support PTT service interworking between IMS and P2P overlay networks. We also introduced our system design and some interworking service scenarios. We confirmed our architecture through implementation and testing.

Comparison of Two Methods for Heparin Sensitivity; Activated Partial Thromboplastin Time Assay using in vitro Heparin-spiked Sample and Anti-Xa Assay using in vivo Heparin-treated Sample

  • Koo, Bon-Kyung;Kwon, Eui-Hoon;Ryu, Kwang-Hyun;Yun, Jae-Won;Kim, Hee-Jin
    • Korean Journal of Clinical Laboratory Science
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    • v.43 no.4
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    • pp.133-137
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    • 2011
  • The monitoring of heparin therapy is using almost aPTT assay. This study is compare to estimating aPTT therapeutic range using in vitro heparin-spiked sample and aPTT therapeutic range using in vivo heparin-treated sample. Normal pooled plasma was collected from 20 healthy representative individuals. 11 concentration of heparinized plasmas from 0 U/mL to 1.0 U/mL at intervals of 0.1 U/mL made by addition of heparin to normal pooled plasma were measured aPTT. The aPTT therapeutic range was performed through correlation analysis between heparin level 0.2 to 0.4 U/mL and aPTT. 30 plasmas from patients on heparin therapy were measured aPTT and anti-Xa activity. The aPTT therapeutic range was performed through correlation analysis between anti-Xa activity 0.3 to 0.7 U/mL and aPTT. The aPTT therapeutic range corresponded by heparin level-vs-aPTT value regression analysis was 60.7 to 102.4 seconds. The aPTT therapeutic range corresponded by anti-Xa activity-vs-aPTT value regression analysis was 85.3 to 147.5 seconds. The validation of heparin sensitivity using in-vitro heparin sample was not considered. The establishing aPTT therapeutic range is recommended anti-Xa activity using in-vivo sample.

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Characterization of Nanofibrous and Microfibrous Web Fabricated Using Polyurethane-Impregnated Poly(trimethylene terephthalate) (Polyurethane 함침된 Poly(trimethylene terephthalate) 나노섬유 웹과 마이크로섬유 웹의 특성 분석)

  • Park, Ko Eun;Kang, Yun Ok;Park, Cho Hee;Nam, Young Sik;Kim, Jin Hong;Park, Won Ho
    • Textile Science and Engineering
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    • v.50 no.3
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    • pp.180-186
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    • 2013
  • Poly(trimethylene terephthalate) (PTT), a semi-crystalline polyester, has been used in many applications because of its good dyeability and good mechanical properties such as elasticity. Sorona (DuPont) and Corterra (Shell Chemicals) are some trade names of PTT. We describe herein a PTT nanofibrous web fabricated by electrospinning, which is a simple technique for generating nanofibers from a polymer solution and a melt. PTT pellets were dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) followed by electrospinning to yield PTT nanofibers with an average diameter of $900{\pm}97nm$. Then, the PTT nanofibrous web was impregnated with a polyurethane (PU) solution. The resulting material had better mechanical properties and also displayed a lower water contact angle than the PTT nanofibers because a relatively hydrophilic PU was coated onto the PTT nanofibrous web. Additionally, the pilling property of the PU-impregnated PTT nanofibrous web was enhanced by the induced welding among the PTT nanofibers because of PU impregnation. The air permeability of the PTT nanofibrous web was evaluated both before and after PU-impregnation. The results indicated that the PU-impregnated PTT nanofibrous web could be used in various industrial applications.

Time-dependent Properties of Partially Oriented Poly (trimethylene terephthalate)(PTT) Fibers (부분 배향된 Poly(trimethylene terephthalate)(PTT) 섬유의 시간에 따른 특성)

  • 손태원;김남훈;정민기;김영훈;김대선
    • Textile Science and Engineering
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    • v.40 no.3
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    • pp.213-223
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    • 2003
  • Time dependence of several properties such as mechanical, thermal, and structural properties of partially oriented PTT filaments was investigated. PTT was spun on a extruder and drawn to draw ratios 1.5, 2.0, 2.5 and 3.0, and the time-dependence of the properties of samples with different draw ratios was measured for a month. At lower draw ratio, it was found that the glass transition temperature increases and the endothermic peak by molecular relaxation occurs in the glass transition region with increasing ageing time. Similarly, the birefringence decreases with increasing ageing time at lower draw ratios. But for the PTT POY with a high draw ratio of about 3.0, the mechanical properties, birefringence, and thermal properties did not change with ageing time. It suggests that fiber structure of PTT POY can be stabilized at this draw ratio. Based on these result, it was concluded that the fiber structure of PTT POY could be stabilized if it is drawn lip to about DR 3.0.

The Comparison of PTT and Systolic Blood Pressure in a hemorrhaged Rat (출혈을 일으킨 흰쥐에서의 PTT와 수축기 혈압 비교)

  • Shim, Young-Woo;Lee, Ju-Hyung;Yang, Dong-In;Kim, Deok-Won
    • Proceedings of the IEEK Conference
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    • pp.138-140
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    • 2009
  • Hemorrhage shock occupies high rate in trauma patient's mortality and blood pressure is the variance that judges early diagnosis and the effect of remedy. Systolic blood pressure is related to pulse transit time(PTT). PTT means the time that is required to flow from the heart to peripheral artery. PTT is influenced from the length, cross section and stiffness of the blood vessels. It is hard to evaluate the correlation between systolic blood pressure and PTT because they are variable in human body. In this paper, we evaluated the correlation between the systolic blood pressure and PTT in normal and hemorrhage states using standardized rat. PTT is defined as the time differences between the R peak and the peak of pulse wave. The analyzed time differences of ECG and blood pressure are analyzed every 5minutes for 30 seconds when there is before and after bleeding. Before bleeding, systolic blood pressure and PTT are steadily preserved but when the bleeding comes started, systolic blood pressure is declined. However PTT was increased and decreased. Under the circumstance that the standardized rat is controlled by age, the length of the blood vessels, and any disease, it shows that PTT measurement using systolic blood pressure of bleeding is impossible.

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Characterization of Poly(trimethylene terephthalate) Nanofibrous and Microfibrous Web (Poly(trimethylene terephthalate) 나노 섬유 웹과 마이크로 웹의 특성분석)

  • Kang, Yun-Ok;Park, Cho-Hee;Nam, Young-Sik;Kim, Jin-Hong;Park, Won-Ho
    • Textile Science and Engineering
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    • v.47 no.6
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    • pp.399-405
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    • 2010
  • A nanofibrous web was fabricated by electrospinning poly(trimethylene terephthalate)(PTT). The PTT web with an average diameter of 290 nm was obtained by electrospinning from a 16%(w/v) PTT solution, whereas a PTT film was obtained from solution casting. The water contact angle of the PTT web was much higher than that of the PTT film because the web had a nanofibrous structure with a high surface area and surface roughness. The PTT film crystallized isothermally in the temperature range of $182-231^{\circ}C$ and exhibited a multiple melting phenomenon. The degrees of crystallinity of the PTT film and PTT web were 59.2 and $38.7^{\circ}C$ respectively. The crystallinity of the PTT web was lower than that of the PTT film because the web solidified rapidly by fast solvent evaporation during electrospinning. To increase the thickness of the web, the spinning solvent was changed to 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP). As a result, a nanofibrous web with average diameter of 900 nm and thickness of 0.36 mm was obtained under the same electrospinning conditions. The overall porosity of the nanofibrous web was higher than the microfibrous web. The tensile strength and tear strength of the microfibrous web was higher than those of the nanofibrous web, whereas the breaking elongation of the nanofibrous web is higher than that of the microfibrous web.

A Numerical Modelling for the Prediction of Phase Transition Time(Ice-Water) in Frozen Gelatin Matrix by Ohmic Thawing Process

  • Kim, Jee-Yeon;Park, Sung-Hee;Min, Sang-Gi
    • Proceedings of the Korean Society for Food Science of Animal Resources Conference
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    • pp.407-411
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    • 2004
  • Ohmic heating occurs when an electric current is passes through food, resulting in a temperature rise in the product due to the conversion of the electric energy into heat. The time spent in the thawing is critical for product sterility and quality. The objective of this study is to conduct numerical modelling between the effect of ohmic thawing intensity on PTT(phase transition time) at constant concentration and the effect of matrix concentrations on PTT at constant voltage condition. the stronger ohmic thawing intensity resulted in decreasing the PTT. High ohmic intensity causes short PTT. And the higher gelatin concentration, the faster increment of PTT. A numerical modeling was executed to predict the PTT influenced by the power intensity using exponential regression and the PTT influenced by gelatin concentration using logarithmic regression. Therefore, from this numerical model of gelatin matrix, it is possible to estimate exact values extensively.

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