Electrochemical Detection of TNT by Differential Pulse Adsorptive Stripping Voltammetry at Carbon Paste Electrode Modified by 1-Butyl-3-methylimidazolium Tetrafluoroborate

Ha Thi Thu Vu,Hanh Thi Vinh Le,Yen Thi Hai Pham,Hung Quoc Le,Phong Hong Pham 대한화학회 2016 Bulletin of the Korean Chemical Society Vol.37 No.3

Different kinds of materials for electrodes based on glassy carbon, carbon fibers, and modified by an ionic liquid (BMIMBF4) were used to determine 2,4,6-trinitrotoluene (TNT) in water environment by differential pulse adsorptive stripping voltammetry. The modified electrode based on BMIMBF4 showed a better performance than those based on the microelectrode and glassy carbon electrode (GCE) in term of sensitivity. The best performance was obtained with the ionic liquid-modified electrode with 80:10:10 (w/w/w) of the graphite powder/paraffin oil/BMIMBF4 composition in PBS, pH 8. The TNT concentration was linear in the range 1.5 to ~30 ppm for all studied electrodes (r = 0.9978) with a detection limit of 88.6 ppb using IL-CPE (ionic liquid-modified carbon paste electrode). This latter electrode was used to measure real samples taken from Red River, Vietnam. The recovery study for TNT in natural samples gave values from 99.7% to 103.3%. IL-CPE demonstrated long-term stability and reproducibility, with a relative standard deviation of 1.67%.

NecroX-5 prevents hypoxia/reoxygenation injury by inhibiting the mitochondrial calcium uniporter.

Thu, Vu Thi,Kim, Hyoung-Kyu,Long, Le Thanh,Lee, Sung-Ryul,Hanh, Tran My,Ko, Tae Hee,Heo, Hye-Jin,Kim, Nari,Kim, Soon Ha,Ko, Kyung Soo,Rhee, Byoung Doo,Han, Jin British Medical Association 2012 Cardiovascular research Vol.94 No.2

<P>Preservation of mitochondrial function is essential to limit myocardial damage in ischaemic heart disease. We examined the protective effects and mechanism of a new compound, NecroX-5, on rat heart mitochondria in a hypoxia/reoxygenation (HR) model.</P>

Biocompatible membrane from the natural rubber-grafted-(2-hydroxyethyl methacrylate) and its metal removal application

Thu Ha Nguyen,Thi Lan Pham,Anh Quan Cao,Tuan Anh Nguyen,Xuan Minh Vu,Thi My Hanh Le,Van Thuan Le,Seiichi Kawahara,Dai Lam Tran 한국고분자학회 2024 Macromolecular Research Vol.32 No.4

This study describes the preparation and characterization of a green and safe membrane based on a natural polymer for metal adsorption. Natural rubber-grafted-(2-hydroxyethyl methacrylate) with a special nanostructure was synthesized by graft copolymerization of 2-hydroxyethyl methacrylate (HEMA) onto the surface of natural rubber (NR) particles using tert-butylhydroperoxide/tetraethylenepentamine as initiators. Optimal conditions for achieving high conversion and grafting efficiency were identified. Characterization of the as-synthesized samples was performed using Fourier-transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, tensile measurement, swelling degree determination, and cytotoxicity testing. The results revealed that HEMA formed a nanoscale matrix surrounding NR particles, which improved the tensile strength, thermal resistance, and swelling degree of the as-prepared samples. Cytotoxicity testing demonstrated that the membrane was safe for human use, as it did not exhibit toxicity to Vero cells at concentrations up to 1024 μg/mL. Furthermore, the membrane displayed a high adsorption capacity toward Fe3+ and was well described by Koble-Corrigan isotherm model and the first–second-order kinetic equation. Moreover, the membrane demonstrated excellent recyclability maintaining its adsorption ability towards Fe3+ ions over five consecutive cycles. Overall, these findings may recommend the NR-HEMA membrane as a promising candidate for metal removal applications.

A Comparative Study on the Self-help Approach in Rural Development between Vietnam’s New Rural Development and Korea’s Saemaul Undong

Do Thu Trang,Nguyen Thi My Hanh,Vu Thu Trang 대외경제정책연구원 2016 East Asian Economic Review Vol.20 No.1

Vietnam’s “Doi Moi”, initiated in 1986, translated to high economic growth and rapid urbanization for the country, but also widened the gap between rural and urban areas. Vietnam’s National Target Program on New Rural Development for 2010- 2020 was aimed at developing the rural economy and improving the living standards of rural people, but after five years the urban-rural gap remains substantial. Two of the main reasons are the lack of investment capital and lack of effective ways to mobilize community involvement. In contrast, during the 1970s, rural areas in Korea experienced huge improvements under the “Saemaul Undong” movement. The program’s success at promoting sustainable development in Korea’s rural areas has inspired rural programs in other developing countries. In this paper, we compare and contrast the two movements to provide explanations for the different results between the two countries. Based on this analysis, and policy implications stemming from it, we recommend resource mobilization strategies to change villagers’ attitude and increase their involvement in Vietnam’s rural development movement, aligning with the inclusivity principle “people know, people discuss, people do and people check”.

Enhancing photoluminescence of Au – TiO₂ nanoparticles using Drude model

Diem Thi-Xuan Dang,Thi Hanh Thu Vu 한국전기전자학회 2017 전기전자학회논문지 Vol.21 No.3

The enhancement of photoluminescence of Au-TiO₂ nanoparticles by surface plasmon resonance has been studied extensively by experiment in recent years. For the purpose of optimizing the photoluminescence property of Au-TiO₂ nanoparticles, the manufacturing parameters related to the Au nanoparticles and TiO₂ nanoparticles need to be considered. In this paper, Drude model and Maier"s effective volume method are used to analyze the variation of the metal nanoparticle radius, separation between metal nanoparticle and dielectric molecule, and total absorption cross-section with original radiative efficiency on the photoluminescence property of Au-TiO₂ nanoparticles. The results show that to obtain the optimized enhancement factor for photoluminescence process, the size of Au nanoparticle is about 13 − 20 nm , the separation between Au nanoparticle and TiO2 molecule is about 5 −15 nm , the total absorption cross-section of TiO₂ molecules is about 1−100 nm2 and the original radiative efficiency of TiO₂ molecule is weak about 0.001− 0.1 . With these fabrication parameters, the photoluminescence property of Au-TiO₂ nanoparticles can be enhanced several thousand times compared to traditional TiO₂ nanoparticles.

Enhancing photoluminescence of Au - TiO₂ nanoparticles using Drude model

Dang, Diem Thi-Xuan,Vu, Thi Hanh Thu Institute of Korean Electrical and Electronics Eng 2017 전기전자학회논문지 Vol.21 No.3

The enhancement of photoluminescence of Au-$TiO_2$ nanoparticles by surface plasmon resonance has been studied extensively by experiment in recent years. For the purpose of optimizing the photoluminescence property of Au-$TiO_2$ nanoparticles, the manufacturing parameters related to the Au nanoparticles and $TiO_2$ nanoparticles need to be considered. In this paper, Drude model and Maier's effective volume method are used to analyze the variation of the metal nanoparticle radius, separation between metal nanoparticle and dielectric molecule, and total absorption cross-section with original radiative efficiency on the photoluminescence property of Au-$TiO_2$ nanoparticles. The results show that to obtain the optimized enhancement factor for photoluminescence process, the size of Au nanoparticle is about 13 - 20 nm, the separation between Au nanoparticle and $TiO_2$ molecule is about 5 -15 nm, the total absorption cross-section of $TiO_2$ molecules is about $1-100nm^2$ and the original radiative efficiency of $TiO_2$ molecule is weak about 0.001- 0.1. With these fabrication parameters, the photoluminescence property of Au-$TiO_2$ nanoparticles can be enhanced several thousand times compared to traditional $TiO_2$ nanoparticles.

A Laboratory-Scale Study of the Applicability of a Halophilic Sediment Bioelectrochemical System for in situ Reclamation of Water and Sediment in Brackish Aquaculture Ponds: Effects of Operational Conditions on Performance

( Hai The Pham ),( Phuong Ha Vu ),( Thuy Thu Thi Nguyen ),( Ha Viet Thi Bui ),( Huyen Thanh Thi Tran ),( Hanh My Tran ),( Huy Quang Nguyen ),( Byung Hong Kim ) 한국미생물생명공학회(구 한국산업미생물학회) 2019 Journal of microbiology and biotechnology Vol.29 No.10

Sediment bioelectrochemical systems (SBESs) can be integrated into brackish aquaculture ponds for in-situ bioremediation of the pond water and sediment. Such an in-situ system offers advantages including reduced treatment cost, reusability and simple handling. In order to realize such an application potential of the SBES, in this laboratory-scale study we investigated the effect of several controllable and uncontrollable operational factors on the in-situ bioremediation performance of a tank model of a brackish aquaculture pond, into which a SBES was integrated, in comparison with a natural degradation control model. The performance was evaluated in terms of electricity generation by the SBES, Chemical oxygen demand (COD) removal and nitrogen removal of both the tank water and the tank sediment. Real-life conditions of the operational parameters were also experimented to understand the most close-to-practice responses of the system to their changes. Predictable effects of controllable parameters including external resistance and electrode spacing, similar to those reported previously for the BESs, were shown by the results but exceptions were observed. Accordingly, while increasing the electrode spacing reduced the current densities but generally improved COD and nitrogen removal, increasing the external resistance could result in decreased COD removal but also increased nitrogen removal and decreased current densities. However, maximum electricity generation and COD removal efficiency difference of the SBES (versus the control) could be reached with an external resistance of 100 Ω, not with the lowest one of 10 Ω. The effects of uncontrollable parameters such as ambient temperature, salinity and pH of the pond (tank) water were rather unpredictable. Temperatures higher than 35℃ seemed to have more accelaration effect on natural degradation than on bioelectrochemical processes. Changing salinity seriously changed the electricity generation but did not clearly affect the bioremediation performance of the SBES, although at 2.5% salinity the SBES displayed a significantly more efficient removal of nitrogen in the water, compared to the control. Variation of pH to practically extreme levels (5.5 and 8.8) led to increased electricity generations but poorer performances of the SBES (vs. the control) in removing COD and nitrogen. Altogether, the results suggest some distinct responses of the SBES under brackish conditions and imply that COD removal and nitrogen removal in the system are not completely linked to bioelectrochemical processes but electrochemically enriched bacteria can still perform nonbioelectrochemical COD and nitrogen removals more efficiently than natural ones. The results confirm the application potential of the SBES in brackish aquaculture bioremediation and help propose efficient practices to warrant the success of such application in real-life scenarios.

Development of label-free electrochemical lactose biosensor based on graphene/poly(1,5-diaminonaphthalene) film

Binh Hai Nguyen,Binh Thanh Nguyen,Hanh Van Vu,Chuc Van Nguyen,Dzung Tuan Nguyen,Loc Thai Nguyen,Thu Thi Vu,Lam Dai Tran 한국물리학회 2016 Current Applied Physics Vol.16 No.2

In this work, a lactose biosensor was developed by co-immobilizing b-galactosidase (b-Gal) and glucose oxidase (GOx) on microelectrodes pre-modified with Pt/graphene/P(1,5-DAN) for estimation of lactose in dairy products to prevent lactose intolerance. The Pt microelectrode was modified with graphene and 1,5-polydiaminonaphthalene film. Graphene was synthesized by chemical vapor deposition on copper tape and manually transferred to the electrode surface. Polymeric P(1,5-DAN) was grafted on top of the graphene film by electropolymerization. Modified surface of the electrode was characterized by Raman spectra analysis, FE-SEM, AFM and cyclic voltammetry. The results indicated that deposition graphene film on electrode surface induced considerable enhancement in current signal, over 20 times as high as the uncoated electrode surface. The developed sensor was successfully used to determine lactose in model samples with sensitivity, correlation coefficient (R2) and limit of detection (LOD) estimated to be 1.33 mA/(mgml1), 0.995 and 1.3 mg/ml, respectively. The combined graphene and conductive P(1,5-DAN) could serve as a novel sensing platform on electrochemical sensors with superior sensitivity.

The recorded open-circuit voltage and fill factor achievement of a-Si:H p-i-n/HIT-type tandem solar cells by tuning up the crystalline in tunneling recombination junction layer

Kim, Sangho,Dao, Vinh Ai,Trinh, Thanh Thuy,Duy Phong, Pham,Park, Jinjoo,Thi Hanh Thu, Vu,Thuy Ngoc Thuy, Nguyen,Thi Thanh Giang, Ngo,Lee, Sunhwa,Yi, Junsin Institute of Physics 2019 Semiconductor science and technology Vol.34 No.6

<P>In this study, a recorded high open-circuit voltage (V<SUB>oc</SUB>) of 1.61 V and fill factor (FF) of 76.65% of a-Si:H p-i-n/heterojunction with intrinsic thin layer (HIT)-type multi-junction solar cells were achieved using grain size enlargement within the p-type <I>μ</I>c-Si:H layer in a p-type <I>μ</I>c-Si:H/n-type a-Si:H tunneling recombination junction (TRJ) layer. The p-type <I>μ</I>c-Si:H layer’s conductivity increased from 1.74?×?10<SUP>−4</SUP> to 0.1 S cm<SUP>−1</SUP> as the film’s crystallinity increased from 41.5% to 67.5%. The a-Si:H p-i-n/HIT-type multi-junction solar cells also benefited from the tuning up crystalline p-type <I>μ</I>c-Si:H layer, showing the increase of V<SUB>oc</SUB> and FF from 1.5 V and 49.88% to 1.61 V and 76.65%, respectively; while the short-circuit current density (9.38?±?0.2 mA cm<SUP>−2</SUP>) did not change significantly. These are the highest V<SUB>oc</SUB> and FF values achieved in a-Si:H p-i-n/HIT-type multi-junction solar cells, recently. From dark current-voltage analysis, it was deduced that the enhanced crystalline films could assist in suppressing carrier interference in the TRJ layer, thus reduces electric field distortion and mitigates recombination in the device. In summary, an enhanced crystalline p-type <I>μ</I>c-Si:H layer could be a viable option for ensuring an excellent TRJ layer, thus achieved high efficiency of inorganic/c-Si tandem solar cells. Using optimal condition with crystallinity of 74.1%, the photovoltaic parameters of the device yield V<SUB>oc</SUB>, J<SUB>sc</SUB> and FF of 1.51 V, 13.01 mA cm<SUP>−2</SUP> and 71.45%, which in turned giving an efficiency of 14.04% for a-SiGe:H p-i-n/HIT-type tandem solar cell.</P>