A STUDY ON THE DIFFICULTIES IN WRITING ARGUMENTATIVE ESSAYS OF ENGLISH-MAJORED SOPHOMORES AT TAY DO UNIVERSITY, VIETNAM

The research entitled “A study on the difficulties in writing argumentative essays of English-majored sophomores at Tay Do University” was conducted with the purpose of pointing out some common difficulties of sophomores in writing argumentative essays. The participants of this study were 90 English-majored sophomores of course 13, and two teachers who teach English language at Tay Do University. In this study process, questionnaire and interview were used as two instruments to collect the data. The results of the research would show that English majored sophomores met difficulties in term of linguistic competence (vocabulary, grammar and coherence), organization and development of an argumentative essay, and the lack of critical thinking. Article visualizations

Purification and Characterization of High Purity Nano Zirconia by Liquid-Liquid Extraction Using D2EHPA/p-Xylenes

In this paper, Zr(IV) nitrate solution decomposed from Viet Nam zircon concentrate was the source of zirconium extraction by liquid-liquid extraction (L.L.E). The FT-IR and UV-Vis spectra confirmed the extraction of Zr(IV) by D2EHPA/p-xylenes. There were four stages for the purification of impurities from the Zr matrix. First, the extraction of elements in 3.0 M HNO3 by 50% D2EHPA/p-xylenes was conducted. Second, two scrubbing cycles of impurities using 6.0 M HNO3, 76.5% of the total amount of Zr(IV) were retained in the organic phase, and 23.5% remained in the aqueous phase. Third, the stripping of a macro amount of zirconium from loaded D2EHPA has been effectively carried out using 1.5 M H2SO4 with a stripping efficiency of 99.6%. Fourth, concentrated ammonia was added to the solution Zr(IV) after stripping extraction to form precipitate for calcination at 550 °C for the final products. The refined products were characterized by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), EDS, XRF, and diffuse reflectance spectroscopy. The ZrO2 has high purity, is nanospherical, and has a uniform sphere-like morphology with small grain size of less than 30 nm and a bandgap value of about 3.30 eV