• Macromolecular Research
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• v.14 no.4
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• pp.416-423
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• 2006

The dynamic mechanical thermal properties of poly(hexamethylene terephthalate) (PHT), poly(1,4-cyclohexylenedimethylene terephthalate) (PCT) and their P(HT-co-CT) random copolymers in the amorphous state were examined as a function of temperature and frequency. All the samples exhibited two main relaxation processes in the plot of tan ${\delta}$ versus temperature: the primary ${\alpha}$-relaxation associated with the glass transition and the secondary ${\beta}$-relaxation attributed to the local segmental motions of mostly cyclohexylene rings for PCT and to cooperative motions of methylene, carboxyl, and phenylene groups for PHT. Both ${\alpha}$- and ${\beta}$-relaxation temperatures increased with increasing CT content. The activation energy of the ${\alpha}$-relaxation increased with increasing CT content, whereas that of the ${\beta}$-relaxation decreased. The sub-glassy secondary ${\beta}$-relaxation processes of PCT and PHT were investigated in terms of the cooperativity of main-chain segmental motions.

• Phonetics and Speech Sciences
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• v.14 no.3
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• pp.27-40
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• 2022

This study identifies distinguishing features and variability of intonation patterns in Korean phonological phrases. Syllable count and segmental content, which are phonological conditions, of the intonation of phonological phrases were examined. Based on the four syllables, the intonation of a phonological phrase can be set to LHLH as the basic form, and syllable count acts as a condition for making a variation. The "3 syllables or less condition" changes the intonation from a curved line to a straight line. Variation occurs in pitch bandwidth and fluctuation according to segmental content. The first segment affects the phonological phrase formation bandwidth, and the following segment affects the pitch fluctuation. If the first segment has [+aspirate], [+tense], [+continuant], the intonation is formed in the high band, otherwise, it is formed in the low band. If the second or after segment in the intonation realized in the high band has [-aspirate], [-tense], [-continuant], the pitch is lowered to the lowest level of the low bandwidth. In the intonation realized in the low band, [+aspirate], [+tense], [+continuant] is blocked by the second descent of LHLH.

• 한국약용작물학회:학술대회논문집
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• 2012.05a
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• pp.247-248
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• 2012

• The International Journal of Costume Culture
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• v.5 no.2
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• pp.53-65
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• 2002

Morphology of polyester fiber was physically modified by solvent treatment. PET fiber was treated with N,N-dimethylformamide (DMF) at 100, 120, $140^{circ}C$ for 10 minutes without tension. The structural changes in the morphology of DMF-induced modified PET fiber were FTIR and SEM analysis. Also dyeing behavior of DMF-treated polyester fibers with various disperse dyes was studied to detect changes of amorphous area in fine structure. DMF treatment resulted in increases in total void content, degree of crystallinity, trans isomer content, chain folding, segmental mobility and molecular packing, but it resulted in decreases in amorphous orientation, intermolecular forces and individual void size through longitudinal shrinkage, lateral welling and removal of oligomers. Void-size distribution could be estimated from the dye uptake with various sizes of disperse dyes. In contrast to the large increases in dye uptake with small dye molecules, there is no and little dye uptake with the bulkiest dye, which means that void size is bigger or smaller than the volume of each dye. Diffusion rates of dye molecules showed increases. This dyeing study revealed that the disperse dyeing is very effective method for characterizing the internal morphology of polyester fiber.

• The Journal of Internal Korean Medicine
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• v.26 no.4
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• pp.912-917
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• 2005

Caroli's disease is a non-obstructive dilatation of the intrahepatic bile ducts. It is a rare congenital disorder that classically causes saccular ductal dilatation, which usually it segmental dilatation. Caroli's disease is associated with recurrent bacterial cholangitis and stone formation. A 57 years-old female inpatient suffering from cholangitis due to Caroli's disease was admitted at Wonkwang University Jeonju Oriental Medicine Hospital. The patient was treated with herbal medicine such as Yongdamsagan-tang and acupuncture. As result, there was improvement of symptoms. The process and content of treatment and the patient's recovery over general symptoms is described.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.1
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• pp.19-23
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• 2019

The PMMA (polymethyl methacrylate)/clay nanocomposites were synthesized by in situ radical polymerizations with different clay contents (3 and 7 wt%) using microwave heating. The nanostructure, optical, and thermal properties of the synthesized PMMA/clay nanocomposites were measured by XRD, TEM, AFM, UV-vis, and TGA. It was found that the intercalated- or exfoliated structure of PMMA/clay nanocomposites was strongly dependent on the content of clay. Thus, the imposition of microwave-assisted polymerization facilitated a delamination process of layered silicates to achieve exfoliation state of interlayer distance. The PMMA/3 wt% C10A nanocomposite with well-dispersed and exfoliated clay nano-layers showed the good optical transparency similar to pure PMMA in this study. The thermal decomposition rates of the PMMA/clay nanocomposites become to be lower compared to that of the pure PMMA, indicating the intercalated- or exfoliated inorganic silicate has high thermal stability. A possible reason is that the thermally segmental motion of PMMA polymer into inorganic silicate interlayer spacing has increased the thermal stability of the PMMA/clay nanocomposites.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.10a
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• pp.69-70
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• 1997

Polyimides and related polymers, when synthesized from aromatic monomers, have generally rigid chain structures resulting in a low gas permeability. The rigidity of polymer chains reduces the segmental motion of chains and works as a good barrier against gas transport. To overcome the limit of use as materials of gas separation membranes due to low gas permeability, block copolymers with the incorporation of flexible segments like siloxane linkage and ether linkage have been studied. These block copolymers have microphase-separated structures composed of microdomains of flexible poly(dimethylsiloxane) or polyether segments and of rigid polyimides segments. In case of rigid-flexible block copolymers, the characteristics of both phases for gas permeation are of great difference. The permeation of gas molecules occurs favorably through microdomains of flexible segments, whereas those of rigid segments hinder the permeation of gas molecules. Accordingly the increase of content of flexible segments in a rigid polymer matrix will increase the gas permeability of the membrane linearly. However, this prediction does not satisfy enough many experimental results and in particular the drastic increase of the permeability is observed in a certain volume fraction. It was proposed that the gas transport mechanism is dominated by diffusion rather than gas solubility in a certain content of flexible phase if solution-diffusion mechanism is adopted. However, the transition from solubility-dependent to diffusion-dependent cannot be explained by the understanding of mechanism itself. Therefore, we consider an effective chemical path which permeable phase can form in a microheterogenous medium, and percolation concept is introduced to describe the permeability transition at near threshold where for the first time a percolation path occurs. The volume fraction of both phases is defined as V$_{\alpha}$ and V$_{\beta}$ in block copolymers, and the volume of $\beta$ phase in the threshold forming geometrically a traversing channel is defined as V$_{\betac}$. The formation mechanism of shortest chemical channel is schematically depicted in Fig. 1.

• The Korean Journal of Food And Nutrition
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• v.28 no.3
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• pp.470-477
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• 2015

The purpose of this study was to perform a functional component analysis to optimize the recipes for Korean beef main bone area. To optimize the recipes for beef leg bone broth, beef feet broth and tail broth, the quality and physiochemical properties of the dishes were comparatived and investigated. Crude protein, crude fat and moisture showed significant differences among the beef leg bone broth, Beef feet broth and tail broth (p<0.001). All free amino acids showed significant differences, with the exception of cystine and tryptophan (p<0.05). All minerals showed significant differences (p<0.01). Na content was highest in the beef leg bone broth (211.77 mg/kg), followed by beef feet broth (254.40 mg/kg), and tail broth (134.93 mg/kg). Collagen was significantly different each dish (p<0.001), but chondroitin sulfate was not. And all nucleic acids showed significant differences.

• The Journal of Korean Association of Computer Education
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• v.20 no.4
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• pp.1-14
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• 2017

The purpose of this study was to compare the composition of the government guidelines for the educational curriculum of Japan announced in 2016 with the outline of the 2015 revised educational curriculum of Korea. To compare the composition of the national level curricula of the two countries, the composition systems and content details were analyzed along with the trends of emphasis placed on informatics education. The analysis indicated that as for the Japanese government's guidelines, it was suggested that the causes of revisions, and purposes and methods of fulfilling goals be added, and thus the appropriateness of the guidelines was emphasized. As for Korea's revised curriculum, a gap caused by segmental development of the outline and details of the curriculum were found in addition to errors in curricular composition and direction setting which were carried out without consideration to the transition time required or changes of subjects. To ensure sufficiency of the curricular contents and education reflecting the situations of each time phase, the necessity to improve the overall curricular framework was suggested. This study holds significance as it provides the introspective insight that the goals and directions of education cannot be set properly when the curricular framework is established without recognition of the contents.

• Bulletin of the Korean Chemical Society
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• v.9 no.6
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• pp.368-376
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• 1988

Transition metal PSSA ionomers containing Co(II), Ni(II), Cr(III), Ru(III), and Rh(III) are investigated by IR, Far-IR, UV-Vis and DSC. Reliable IR Spectroscopic criteria are established for assessing the degree of ion-exchange of PSSA ionomers and the local structures around metal cations in them. In the hydrated transition metal PSSA ionomers, the ionic groups are solvated by water molecules and there is no significant interactions between sulfonate group and metal cations. The visible spectra indicated that metal cations are present as [M$(H_2O)_6$]$^{n+}$ with Oh symmetry. Their $T_g$ values increase as the extent of ionic site concentration increases, but there is no direct dependence of $T_g$ on the nature of metal cations or their oxidation states. Thus, the water content in PSSA ionomer is found to have dominant influence on $T_g$ of hydrated transition metal PSSA ionomers. Dehydration of the hydrated transition metal PSSA ionomers results in direct interaction between ionic groups and significant color changes of the ionomers due to the changes of the local structures around metal cations. On the base of spectral data, their local structures are discussed. In case of dehydrated 12.8 and 15.8 mol % transition metal PSSA ionomers, no glass transition is observed in 25-$250^{\circ}C$ region and this is believed to arise from the formation of highly crosslinked structures caused by direct coordination of sulfonate groups of metal cations. In the 6.9 mol % transition metal PSSA ionomers, the glass transition is always observed whether they are hydrated or dehydrated and this is though to be caused by the sufficient segmental mobility of the polymer backbone.