[en] Currently, the situation of titanium exploitation and processing in Vietnam is facing difficulties. Titanium mining and processing activities only stop in the field of beneficiation, which doesn't have technology for deep processing of Ilmenite concentrate. There have been many studies on the preparation of TiO₂ from ilmenite concentrate by different methods such as sulfate method, alkali resolution method, ammonium fluoride resolution method ... which have been done in Vietnam. However, most of these solutions have the disadvantages of generating large amounts of wastewater, incurring an additional iron recovery process, and high ammonium fluoride recirculation costs due to additional concentration steps. To reduce costs and expand the line of titanium oxide products of satisfactory quality for pigments and titanium metal production materials, titanium fluoride sublimation technology - the dry method should be researched to reduced wastewater volume and reduced ammonium fluoride recirculating concentration cost. Therefore, the implementation of a scientific and technological research project and processing of ilmenite concentrate using fluoride technology to separate titanium fluoride to produce white TiO₂ powder in Vietnam is urgent and completely suitable for the real situation domestic economy.

[en] By embedding a thin ZnO layer sandwiched between the hole transport and photoactive layers, organic solar cells (OSC) based on poly(3-hexylthiophene) (P3HT) were prepared by spincoating. UV–vis spectra of the composite films showed that ZnO exhibited a suitable buffer layer that could block holes movement throughout the heterojunction of ITO/ZnO. The enhancement in the fill factor (FF) of the buffer-OSC (BOSC) is attributed to the presence of nanoheterojunctions of ZnO/PCBM and ZnO/ITO. For the normal temperature, the increase of the open-circuit potential and short-circuit current resulted in an overall increase of the energy conversion efficiency. Comparing to OSCs without buffer layer (WOSC), the laminar structure of ITO/ZnO/P3HT/PCBM/Li/Al cells possess a much larger photovoltaic energy conversion efficiency, namely 2.12% (for BOSC) compared to 1.75% (for WOSC). (paper)

[en] It is shown that an effective (nonrenormalizable) coupling of lepton multiplets to scalar triplets in the 331 model with sterile/exotic neutrinos, can be a good way for generating neutrino masses of different types. The method is simple and avoids radiative/loop calculations which, sometimes, are long and complicated. Basing on some astrophysical arguments it is also stated that the scale of SU(3)_L symmetry breaking is at TeV scale, in agreement with earlier investigations. Or equivalently, starting from this symmetry breaking scale we could have sterile/exotic neutrinos with mass of a few keV's which could be used to explain several astrophysical and cosmological puzzles, such as the dark matter, the fast motion of the observed pulsars, the re-ionization of the Universe, etc