Advanced Magnetic Materials Produced by Using Rapid Quenching Technology

Nguyen Hoang Nghi,Nguyen Van Dung,Trinh Thi Thanh Nga,Bui Thi Khanh Nhung,Mai Thanh Tung,Nguyen Huu Tinh,Hoang Nhat Hieu,Bui Xuan Chien,Nguyen Thi Hong Tam 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.6

Amorphous alloys produced by using a rapid quenching technique are considered to be a precursor for producing nanosized and multiphase structures by precipitation (the top-down method). By using this technique, several new magnetic materials with different magnetic properties based on different physical mechanisms have been manufactured and investigated. Three new magnetic materials, a nanocrystalline soft magnetic material, a soft-hard permanent magnet and a Me-3d granular alloy with a GMR effect, what were prepared under local conditions, are presented and discussed in the experimental point of view. Amorphous alloys produced by using a rapid quenching technique are considered to be a precursor for producing nanosized and multiphase structures by precipitation (the top-down method). By using this technique, several new magnetic materials with different magnetic properties based on different physical mechanisms have been manufactured and investigated. Three new magnetic materials, a nanocrystalline soft magnetic material, a soft-hard permanent magnet and a Me-3d granular alloy with a GMR effect, what were prepared under local conditions, are presented and discussed in the experimental point of view.

Export-platform FDI and local industries

Huu Thanh Tam Nguyen,Malika Hattab-Christmann 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10

The development of regional economic integration at the end of the century lead to emergence and development of a particular foreign investment know as "export-platform direct foreign investment". This paper aims to examine impacts of this investment on Vietnamese export-oriented industries (during the period 2000-2006). Firstly, competition effect is negative on production of domestic firms. A rise of 10% of foreign firms" production share in an industry goes with a decrease of 5.9% of domestic firms one. Even so, it does not affect their demographic balance. Consequently, the net effect on local production is negative. The same rise of foreign finns" production share leads to a drop of 12.3% of local one. Then, the presence of MNF generates technological externalities on local production. If their staff steps up by 1%, local production increases by 1.6% ceteris paribus. Furthermore, these extern-alities will be higher in industries where foreign firms are numerous. They also are more important in industries where employees hired by domestic firms are qualified. However, their diffusion will be prevented if the technology used by these foreign firms is advanced. Then, these externalities on local production seem to be brought by technological spillovers on production of domestic firms because any ones are not found on demography of these firms. Lastly, with regard to this demography, MNF only facilitate entry of domestic firms in industries where they are sufficiently numerous or that qualification of worker recruited by domestic firms is sufficiently high.

Organic Photocatalysts Based on Dithieno[3,2-b:2',3'-d]pyrrole for Photoinduced Metal-Free Atom Transfer Radical Polymerization

Nhung Thanh Thi Truong,Tam Huu Nguyen,Bao Kim Doan,Le-Thu T. Nguyen,Tam Hoang Luu,Chau Duc Tran,Thiet Quoc Nguyen,Ha Tran Nguyen 한국고분자학회 2021 Macromolecular Research Vol.29 No.11

In this research, three organic photocatalysts, 4-(4H-dithieno[3,2-b:2',3'- d]pyrrol-4-yl)-N,N-diphenylaniline, 4-(pyren-1-yl)-4H-dithieno[3,2-b:2',3'-d]pyrrole and 4-(6b,10-dihydroperylen-3-yl)-4H-dithieno[3,2-b:2',3'-d]pyrrole have been successfully synthesized through C-N coupling reactions. The chemical structures and the optical properties of the obtained organic photocatalysts have been characterized via 1H NMR,13C NMR, elemental analysis, and UV-Vis spectroscopy. Next, these dithieno[3,2-b:2′,3′-d]pyrrole-based photocatalysts have been used for the polymerization of methyl methacrylate, 2-(dimethylamino)ethyl methacrylate and tert-butyl methacrylate monomers under 365 nm UV irradiation, resulting in (meth)acrylate polymers with controlled molecular weights and low polydispersity indexes.

A Facile Synthesis of WS2/g-C3N4 Composites with Improved Photocatalytic Activity

Huu Ha Tran,Duy Huong Truong,Thanh Tam Truong,Thi Xuan Dieu Nguyen,Ying-Shi Jin,김성진,Vien Vo 대한화학회 2018 Bulletin of the Korean Chemical Society Vol.39 No.8

Visible-light-driven photocatalysis has received considerable attention in the environmental treatment in recent years. In this paper, WS2/g-C3N4 composite photocatalysts with various contents of WS2 and g-C3N4 were synthesized by a facile method via heating the mixtures of tungstic acid and thiourea, and denoted as nWCN, where n is weight ratio of thiourea to tungstic acid. The composites were characterized by XRD, SEM, EDS, TEM, IR, Raman spectroscopy, XPS, TGA, and UV?vis DRS. The characterizations reveal that the composites contain WS2 nanosheets coated by g-C3N4 and the relative content of WS2 in the composites decreases with increasing amount of thiourea in the reaction mixtures. All the composites exhibited the better photocatalytic activity in degradation of methylene blue in aqueous solution than the single components, WS2, and g-C3N4. Among them, 7WCN sample performed the highest activity. A synergistic effect between WS2 and g-C3N4 in photocatalytic activity for the composites was observed.

A new hybrid sewage treatment system combining a rolled pipe system and membrane bioreactor to improve the biological nitrogen removal efficiency: A pilot study

Bach, Quang-Vu,Le, Van Tam,Yoon, Yong Soo,Bui, Xuan Thanh,Chung, Woojin,Chang, Soon Woong,Ngo, Huu Hao,Guo, Wenshan,Nguyen, Dinh Duc Elsevier 2018 Journal of Cleaner Production Vol.178 No.-

<P><B>Abstract</B></P> <P>A new hybrid pilot plant configuration based on a modularized rolled pipe system (RPS) combined with a submerged flat sheet membrane bioreactor (MBR) was investigated to enhance the sewage treatment and membrane performance. The system was operated under actual conditions for more than four months, that is, at a constant flow rate of 30 m³/d and with two internal recycling ratios. The results indicate that the hybrid system produces an excellent effluent quality and considerably mitigated membrane fouling. The average concentrations of SS, COD, TN, NH<SUB>4</SUB> <SUP>+</SUP>-N, NO<SUB>3</SUB> <SUP>−</SUP>-N, and PO<SUB>4</SUB> <SUP>3-</SUP>-P remained below 2.81, 8.29, 8.77, 0.15, 8.17, and 1.49 mg/L, respectively. It was estimated that the periodic chemical cleaning of the membrane could be extended to approximately six months. The MBR and RPS can virtually complete nitrification and denitrification, respectively. The highest average denitrification rate of the RPS is 116.95 mg NO<SUB>3</SUB>-N/(g MLVSS d), with a hydraulic retention time of 1.05 h. Therefore, the RPS–MBR hybrid system has potential to improve the sewage treatability. The emerging RPS technique can obtain high rates of denitrification coupled with a compact design, ease of installation, and small footprint.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A new hybrid sewage treatment system was explored. </LI> <LI> Excellent denitrification is achieved with the novel rolled pipe system. </LI> <LI> High rates of simultaneous nitrification and denitrification are obtained. </LI> <LI> The hybrid system performs well in removing organic and nitrogen compounds. </LI> <LI> The membrane fouling rate of the hybrid system is significantly low. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Phenothiazine Derivative as Organic Photocatalyst for Metal Free Atom Transfer Radical Polymerization

Hoan Minh Tran,Lan Ngoc Tan Phan,Thang Van Le,Thuy Thuy Truong,Tam Huu Nguyen,Khuong Tung Truong,Le-Thu T. Nguyen,Mai Thanh Phong,Ha Tran Nguyen 한국고분자학회 2019 폴리머 Vol.43 No.4

A novel organic photocatalyst, 4-(10H-phenothiazin-10-yl)-N,N-diphenylaniline (PDPA) has been successfully synthesized from triphenylamine and phenothiazine moiety via Buchwald-Hartwig C-N coupling. The chemical structure of catalyst was characterized via proton nuclear magnetic resonance (1H NMR) and the optical properties were investigated via UV-vis spectroscopy. The PDPA has been applied as an organic photocatalyst for metal free atom transfer radical polymerization (O-ATRP). The well-controlled molecular weights of polymethacrylates have been obtained with high yield of 95% and narrow polydispersity index (Đ).