Three- and four-arm poly(ethylene oxide) (PEOs) fractions have been synthesized to investigate the molecular shape dependence on polymer crystallization, melting, and annealing behaviors. Each arm in these star PEOs has a molecular weight (MW) of 2220 (M a = 2220) and has been coupled using 1,3,5-benzene tricarbonyl trichloride and 1,2,4,5-benzene tetracarboxylic acid. Molecular parameters have been characterized via vapor pressure osmometry, gel permeation chromatography, light scattering, and Fourier transfer infrared spectroscopy. The coupling agents containing phenylene groups act as chemical defects at the center of the molecule. Diffusion in the melt of these star PEOs as measured by nuclear magnetic resonance shows that at constant temperature the self-diffusion slows down with an increase in the number of arms. Wide-angle X-ray diffraction (WAXD) experiments indicate that these star PEOs possess monoclinic crystal structures identical to those of linear PEOs, implying that the coupling agents are rejected from the crystals. The overall crystallization rate of the star PEOs decreases with increasing crystallization temperature (T c) and number of arms. On the basis of synchrotron small-angle X-ray scattering (SAXS) experiments, it has been found that during the initial isothermal crystallization at low undercoolings (Δ T's) the long period gradually decreases with increasing time before reaching a thickness corresponding to the summation of the thicknesses of the crystals with an extended arm length and two layers consisting of the coupling agent and the uncrystallized PEO arm. The final crystals possess the regular overall molecular conformations. At high Δ T's, the long period remains constant both during and after crystallization with no observed thinning process. Only irregular overall molecular conformations in these crystals can be expected. The dependence of the final long period on T c, as determined by SAXS, is remarkably similar to the melting temperature response to T c obtained via differential scanning calorimetry (DSC). The annealing effect has been examined for samples crystallized at 32 °C, subsequently heated to 50 °C, and isothermally annealed for various periods of time. A partial melting upon heating and recrystallization during annealing can be identified based on the combined experimental results obtained from DSC, WAXD, and SAXS methods.

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This study aims to improve the performance of identifying grammatical functions between an adnoun clause and a noun phrase in Korean. The key task is to determine the relation between the two constituents in terms of such functional categories as subject, object, adverbial, and appositive. The problem is mainly caused by the fact that functional morphemes, which are considered to be crucial for identifying the relation, are frequently omitted in the noun phrases. To tackle this problem, we propose to employ the Support Vector Machines(SVM) in determining the grammatical functions. Through an experiment with a tagged corpus for training SVMs, the proposed model is found to be useful.