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Yong-Won Lee,Robert Kantor 서울대학교 언어교육원 2015 語學硏究 Vol.51 No.3
The main purposes of the current study are to: (a) examine the interactional effects among test-takers, tasks, and raters, as well as the main effects of these facets, in an ESL writing test consisting of both integrated and independent writing tasks and (b) thereby identify additional sources of score variability and error in the rating of test-taker responses. A total of 162 test-takers with 29 different L1 backgrounds participated in the study, each of whom took the same six writing tasks, which included 3 Listening-Writing (LW), 2 Reading-Writing (RW), and 1 Independent Writing (IW) tasks. Each of the essays was rated by each of the 6 trained raters to obtain a completely-crossed data matrix for the test-takers, tasks, and raters. A computer program, FACETS (Linacre, 1998), was used to calibrate the test-takers, tasks, and raters and conduct interaction analysis on 970 essays. Results of the analyses revealed that raters seemed to be having slight difficulty in maintaining a consistent level of severity across all of the 6 tasks and that a close inspection of the rating patterns of selected test-takers demonstrated the usefulness of interaction analysis in pinpointing particular combinations of facet elements with unusual interaction patterns. The implications of these findings for writing assessment are discussed along with the avenues for further investigation.
Park, Seung Koo,Farris, Richard J.,Kantor, Simon W. The Korean Fiber Society 2004 Fibers and polymers Vol.5 No.2
In order to assess the potential of the hydroxy-containing polyamic acid (PHAA) synthesized from 3,3'-dihydroxy benzidine and pyromellitic dianhydride for a fire-safe polymer, the cyclization pathway of PHAA has been investigated using a model compound prepared from 2-aminophenol and phthalic anhydride. The reaction was monitored. by $^1{H-nuclear}$ magnetic resonance. N-(2-hydroxyphenyl) phthalamic acid is converted to N-(2-hydroxyphenyl) phthalimide at ca. 175$^{\circ}C$, showing endothermic reaction. The imide structure is rearranged to the benzoxazole structure over ca. $400^{\circ}C$. These results are similar with that of PHAA. According to pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) data, water and carbon dioxide are released during the cyclization and rearrangement reaction. One DMAc molecule is complexed with one carboxyl acid group in PHAA, which accelerates the imidization process to release more easily the flame retardant, water.
Synthesis and Cyclization of Aromatic Polyhydroxyamides Containing Trifluoromethyl Groups
Baik, Doo-Hyun,Kim, Hae-Young,Simon W. Kantor The Korean Fiber Society 2002 Fibers and polymers Vol.3 No.3
Polyhydroxyamides derivatized with trifluorormethyl ether and trifluoromethyl ester groups were investigated as possible candidates for a new flame retardant polymer. Model compounds for these derivatized polyhydroxyamides were synthesized and their cyclization chemistry was investigated. The model compound study revealed that trifluorornethyl ester group containing model compounds can cyclize on heating, while trifluoromethyl ether group containing model compounds cannot. The non-fluorinated ether and ether derivatives behaved similarly. The trifluoromethyl ester derivatized polyhydroxyamides were synthesized according to the procedures for the model compounds. TGA characterization revealed that the fluorinated polymers have nearly same thermal stability as the underivatized PHA after cyclization.