The Effect of the Ratio of C45 Carbon to Graphene on the Si/C Composite Materials Used as Anode for Lithium-ion Batteries

Hoang Anh Nguyen,Thi Nam Pham,Le Thanh Nguyen Huynh,Tran Ha Trang Nguyen,Viet Hai Le,Nguyen Thai Hoang,Thi Thom Nguyen,Thi Thu Trang Nguyen,Dai Lam Tran,Thi Mai Thanh Dinh The Korean Electrochemical Society 2024 Journal of electrochemical science and technology Vol.15 No.2

Due to its high theoretical capacity, Silicon (Si) has shown great potential as an anode material for lithium-ion batteries (LIBs). However, the large volume change of Si during cycling leads to poor cycling stability and low Coulombic efficiency. In this study, we synthesized Si/Carbon C45:Graphene composites using a ball-milling method with a fixed Si content (20%) and investigated the influence of the C45/Gr ratio on the electrochemical performance of the composites. The results showed that carbon C45 networks can provide good conductivity, but tend to break at Si locations, resulting in poor conductivity. However, the addition of graphene helps to reconnect the broken C45 networks, improving the conductivity of the composite. Moreover, the C45 can also act as a protective coating around Si particles, reducing the volume expansion of Si during charging/discharging cycles. The Si/C45:Gr (70:10 wt%) composite exhibits improved electrochemical performance with high capacity (~1660 mAh g^-1 at 0.1 C) and cycling stability (~1370 mAh g^-1 after 100 cycles). This work highlights the effective role of carbon C45 and graphene in Si/C composites for enhancing the performance of Si-based anode materials for LIBs.

The Effectiveness of Financial Sources for Climate Change in Vietnam

Thi Nhung NGUYEN(Thi Nhung NGUYEN ),Minh Hoa NGUYEN(Minh Hoa NGUYEN ),Thi Phuong Anh VU(Thi Phuong Anh VU ),Thi Hoang Anh DO(Thi Hoang Anh DO ) 한국유통과학회 2023 The Journal of Asian Finance, Economics and Busine Vol.10 No.1

This research aims to give information about the current situation of five financial sources for climate change in Vietnam, including (i) the State budget used by ministries; (ii) the State budget used by provinces; (iii) Bilateral funds; (iv) Multilateral funds; and (v) Private funds, and then classify them in line with the effectiveness. The working paper’s secondary data on spending on CC-related activities, collected from reports of six ministries and 29 provinces, show that the State budget has been crucial in subsidizing CC-related activities in Vietnam. Moreover, domestic investment has accounted for a major part of the total expenditure of ministries and provinces for climate change. In addition, by using primary data collected from surveys sent to twelve experts from 5 groups, such as researchers, practical experts, managers of private funding organizations (such as banks and enterprises), managers of international funding organizations and beneficiaries, and then analyzing the data through the AHP method, the study shows that all climate finance sources in Vietnam are still not very effective. However, private sector funds are considered the most effective financial source for responding to climate change.

Effect of salicylic acid and yeast extract on curcuminoids biosynthesis gene expression and curcumin accumulation in cells of Curcuma zedoaria

Nguyen Hoang Loc,Truong Thi Phuong Lan,Nguyen Duc Huy,Nguyen Ngoc Luong,Hoang Tan Quang,Trinh Huu Tan,Le Thi Anh Thu,Nguyen Xuan Huy 한국식물생명공학회 2019 JOURNAL OF PLANT BIOTECHNOLOGY Vol.46 No.3

The aim of this study is to evaluate the effect of yeast extract (YE) and salicylic acid (SA) on the expression of curcuminoid-biosynthesis genes (CzDCS and CURS1-3), and accumulation of curcumin in Curcuma zedoaria cell cultures. The results showed that, in cells treated with YE or SA, the expression levels of curcuminoid genes were 1.14- to 3.64-fold higher than the control (untreated cells), in which the YE exhibited a stronger effect in comparison with SA. Curcumin accumulation also tended to be similar to gene expression, curcumin contents in YE- or SA-treated cells were 1.61- to 2.53-fold higher than the control. The SA treatment at the fifth day of culture stimulated the curcumin accumulation and expression in all four genes compared to that at the beginning. While the YE treatments gave different results, the CzCURS1 and CzCURS3 genes were expressed strongly in cells that were treated at the beginning. However, the CzDCS and CzCURS2 genes showed the opposite expression pattern, they were activated strongly in the treatments at day five of the culture. However, the content of curcumin reached its maximum value on the fifth day of culture in all investigations.

Applications of Magnetite Nanoparticles for Water Treatment and for DNA and Cell Separation

Nguyen Hoang Hai,Nguyen Chau,Nguyen Hoang Luong,Nguyen Thi Van Anh,Phan Tuan Nghia 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.3

Magnetic nanoparticles with a diameter of 15 nm prepared by using the coprecipitation method have been applied to enforce the sedimentation of the solid waste, to adsorb the arsenic ions in water, to increase the DNA concentration by using a magnetic eld for the electrochemical DNA sensor and to separate the helper CD4+ T cells to determine the number of the cells in blood. A combination of magnetic nanoparticles and alum makes the solid waste in water under a magnetic field aggregate a dozen times faster than under the gravity alone. A concentration of 0.1 mg/l of arsenic in water was reduced to a value lower than the permissible concentration of 0.01 mg/l after few minutes of stirring. The particles functionalized with 3-aminopropyl triethoxysilane were used to enrich the DNA of the Herpes virus, which extended the sensitivity of an electrochemical sensor down to a concentration lower than nM/l. The particles coated with fluorescent-labeled antiCD4 antibody were used to count the helper CD4+ T cells. The fluorescence signals of the particle/cell system were two times stronger than those of the uorescence antiCD4 cell system. This can be used for the treatment of an HIV-infected patient with a simple fluorescent microscope. Magnetic nanoparticles with a diameter of 15 nm prepared by using the coprecipitation method have been applied to enforce the sedimentation of the solid waste, to adsorb the arsenic ions in water, to increase the DNA concentration by using a magnetic eld for the electrochemical DNA sensor and to separate the helper CD4+ T cells to determine the number of the cells in blood. A combination of magnetic nanoparticles and alum makes the solid waste in water under a magnetic field aggregate a dozen times faster than under the gravity alone. A concentration of 0.1 mg/l of arsenic in water was reduced to a value lower than the permissible concentration of 0.01 mg/l after few minutes of stirring. The particles functionalized with 3-aminopropyl triethoxysilane were used to enrich the DNA of the Herpes virus, which extended the sensitivity of an electrochemical sensor down to a concentration lower than nM/l. The particles coated with fluorescent-labeled antiCD4 antibody were used to count the helper CD4+ T cells. The fluorescence signals of the particle/cell system were two times stronger than those of the uorescence antiCD4 cell system. This can be used for the treatment of an HIV-infected patient with a simple fluorescent microscope.

Optimization of the eco-friendly synthesis of graphene oxide from graphite using Plackett–Burman and Box–Behnken models for industrial production orientation

Phuc Nguyen Thien,Giang Nguyen Thi Huong,An Vu Nguyen Thien Truong,Nam Nguyen Thanh Hoai,Anh Ly Duc,Nguyen Huynh Cam,An Hoang,Phong Mai Thanh,Hieu Nguyen Huu 한국탄소학회 2023 Carbon Letters Vol.33 No.2

In this study, graphene oxide (GO) was synthesized by the improved Hummers’ method. The degree of oxidation from graphite (Gi) to GO was determined through interlayer spacing calculated from X–ray diffraction. Besides, the effect of KMnO4:Gi ratios (X1), H2SO4 volume (X2), oxidation temperature (X3), oxidation time of stage 1 (X4), and oxidation time of stage 2 (X5) was screened by the Plackett–Burman model. The simultaneous impact of three factors that influenced the degree of oxidation (X1, X2, and X3) was studied by the Box–Behnken experimental model of response surface methodology to achieve suitable conditions for the GO synthesis process. The characterization of GO product was investigated via the modern analytical methods: X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, UV–Vis spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. In addition, the study was also carried out on a pilot scale for orientation in industrial application with the yield of 14 g/batch.

Uptake of arsenic and heavy metals by native plants growing near Nui Phao multi-metal mine, northern Vietnam

Ha, Nguyen Thi Hoang,Ha, Nguyen Thi,Nga, Tran Thi Huyen,Minh, Nguyen Ngoc,Anh, Bui Thi Kim,Hang, Nguyen Thi An,Duc, Nguyen Anh,Nhuan, Mai Trong,Kim, Kyoung-Woong Elsevier 2019 Applied geochemistry Vol.108 No.-

<P><B>Abstract</B></P> <P>Phytoremediation is a plant-based, environment-friendly, and cost-effective technology that can be potentially used to remediate contaminated media. This study was conducted to evaluate the phytoextraction and phytostabilization potential, two common techniques of phytoremediation, of 21 plant species growing naturally at the largest tungsten (W) mine in Vietnam—the second largest production of W in the world. The average concentrations in different soil fractions were in the following order: residue > organically complexed, Fe- and Mn oxide-bound > carbonate bound > exchangeable. The total concentrations of arsenic (As), cadmium (Cd), copper (Cu), and zinc (Zn) in the soil varied by 34–3390, 4.87–81.6, 14.3–2080, and 21.9–370 mg/kg, respectively. The concentrations of As, Cd, Cu, and Zn in the shoots ranged 0.71–2400, 0.05–5.55, 4.81–249, and 13.3–380 mg/kg-DW, respectively. The concentrations of As and Cd in all soil samples and Cu in 70% of soil samples collected around the mine fluctuated within 2–227, 3–54, and up to 21-folds higher than the maximum allowable limit for agricultural soils in Vietnam (QCVN 03-MT:2015/BTNMT). The results indicated that hyperaccumulation levels (mg/kg-DW) were obtained for only As in <I>Pityrogramma calomelanos</I> (2400) and <I>Pteris vittata</I> L. (1860). Based on the recorded hyperaccumulation levels, translocation and accumulation factors, biomass, and fast growth of these plants, <I>P. calomelanos</I> and <I>P. vittata</I> were considered to be promising native plants for the phytoextraction of As contaminated soils. <I>Bidens pilosa</I> L. also has great potential for phytostabilization of mining soils contaminated with As and heavy metals.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Soils near multi-metal (W–F–Cu–Au–Bi) mine were contaminated with As, Cd, Cu. </LI> <LI> Arsenic in shoots were in order of Fern > Monocotyledonae > Dicotyledonae. </LI> <LI> <I>Pityrogramma calomelanos</I> and <I>Pteris vittata</I> L. suggested for phytoextraction of As. </LI> <LI> <I>Bidens pilosa</I> L. suggested for the phytostabilization of mining contaminated soils. </LI> </UL> </P>

The extraction of lignocelluloses and silica from rice husk using a single biorefinery process and their characteristics

Ngoc Thuy Nguyen,Nhat Thong Tran,Tan Phat Phan,Anh Thu Nguyen,My Xuyen T. Nguyen,Nguyen Ngan Nguyen,Young Ho Ko,Dai Hai Nguyen,Tran T.T. Van,DongQuy Hoang 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.108 No.-

While the efficient usage of biomass waste can significantly help in addressing environmental issues,there are only a few reports that discuss about processing such waste effectively at a low-cost. Such challengearises from the strong association between the components biomass. In this study, an abundantagricultural byproduct, rice husk (RH), was used as the starting resource. A simple biorefining processof alkaline peroxide treatment followed by acid precipitation and ethanol extraction was performed onRH to obtain cellulose, hemicellulose, lignin, and silica. The chemical structures, morphologies, andphysic-chemical properties of the separated components were identified through a wide range of characterizationapproaches. The final products obtained from of this process were (i) bundles of fiber-likecellulose with a fiber width of 6 mm and (ii) small particles of hemicellulose and lignin with nonuniformshapes. The lignocelluloses products had over 90 wt% carbon with 52.28% crystalline ratio. Meanwhile, the other products comprising hemicelluloses, lignin, and silica were amorphous. The outcomeof this study contributes to expanding and developing the simple and efficient conversion processof biomass waste into sustainable value-added materials. It is crucial to reduce the environmental impactby using renewable materials as the new building block resources for synthetic chemicals.

A Combination of Independent Component Analysis, Relative Wavelet Energy, and Support Vector Machine for Mental State Classification

Hoang-Anh T. Nguyen,Huy-Hoang Tran,Thang T. Vu,T.T. Quyen Bui 제어로봇시스템학회 2016 제어로봇시스템학회 국제학술대회 논문집 Vol.2016 No.10

Mental state classification is an important step for realizing a control system based on electroencephalography (EEG) signals which could benefit a lot of paralyzed people including the locked-in or Amyotrophic Lateral Sclerosis. Considering that EEG signals are nonstationary and often contaminated by various types of artifacts, classifying thoughts into correct mental states is not a trivial problem. In this work, our contribution is that we present and realize a novel model which integrates different techniques: Independent component analysis (ICA), relative wavelet energy, and support vector machine (SVM) for the same task. We applied our model to classify thoughts in two types of experiment whether with two or three mental states. The experimental results show that the presented model outperforms other models using Artificial Neural Network, K-Nearest Neighbors, etc.

Magnetic Properties of Bulk Nd50Co10Fe30Al10-xVx Alloys

Hoang Duc Anh,Cao Xuan Huu,Nguyen Chau,Nguyen Hoang Luong 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5

This paper presents the results of study on the structure and the properties of the bulk Nd50Co₁0Fe₃0Al₁0xVx (x = 0, 2, 4, 6, 8, 10) alloys prepared by arc-melting and suction cast- ing with water cooling. The cast surfaces of the samples are partly crystalline and the amorphous volume fraction increases with distance into cast samples. With increasing V content, the crys- tallization volume fraction increases and for x = 10, the alloy is fully crystallized. In general, the melting temperature increases, but Ms and Hc decrease with V content. The Curie temperature increases clearly from 430 K (x = 0) to 512 K (x = 10). Thermomagnetic measurements of all samples done in low elds indicate the existence of the Hopkinson effect, which shows a coherent rotation magnetization and a strong reduction of the magnetic anisotropy in partly crystallized sam- ples. The eld-cooled (FC) and the zero field-cooled (ZFC) curves measured in low elds reveal an obvious separation from each other at low temperatures, pointing to the existence of a cluster-glass state. The cluster-glass fraction decreases with increasing V content in the samples. This paper presents the results of study on the structure and the properties of the bulk Nd50Co₁0Fe₃0Al₁0xVx (x = 0, 2, 4, 6, 8, 10) alloys prepared by arc-melting and suction cast- ing with water cooling. The cast surfaces of the samples are partly crystalline and the amorphous volume fraction increases with distance into cast samples. With increasing V content, the crys- tallization volume fraction increases and for x = 10, the alloy is fully crystallized. In general, the melting temperature increases, but Ms and Hc decrease with V content. The Curie temperature increases clearly from 430 K (x = 0) to 512 K (x = 10). Thermomagnetic measurements of all samples done in low elds indicate the existence of the Hopkinson effect, which shows a coherent rotation magnetization and a strong reduction of the magnetic anisotropy in partly crystallized sam- ples. The eld-cooled (FC) and the zero field-cooled (ZFC) curves measured in low elds reveal an obvious separation from each other at low temperatures, pointing to the existence of a cluster-glass state. The cluster-glass fraction decreases with increasing V content in the samples.

ĐÁNH GIÁ KHẢ NĂNG LÀM LÀNH VẾT BỎNG TRÊN CHUỘT CỦA HYDROGEL TỪ AgNP-CHITOSAN-CURCUMIN

Hoang Ngoc Anh Nhan,Nguyen Ba Trung,Giang Thi Kim Lien,Truong Thi My Phuong,Ho Kha Vinh Nhan,Pham Xuan Anh 한국베트남학회 2023 베트남연구 Vol.21 No.1

Skin burn is one of the major causes of morbidity and mortality in burn patients due to its susceptibility to infection. The disruption of the epidermal barrier, combined with the denaturation of proteins and lipids, provides a fertile environment that is rich in bacterial nutrients for microbial growth, making it significantly prone to infection. This study aimed to formulate a thermoresponsive hydrogel containing silver nanoparticles (300 ppm), oligo chitosan 2%, and curcumin (0.1%) in the polymer pluronic F127 matrix with a final concentration of 13% to effectively promote the healing of skin wounds. The prepared thermoresponsive hydrogel was investigated for its physical and chemical stability, gelation temperature, and chemical composition. In addition to in vitro antibacterial activity against Staphylococcus aureus found in burn infections, in vivo burn healing and antibacterial activities were also investigated and compared with those of a commercial product using burn-induced infected wounds in mice. The formulation showed antibacterial activity with effective values for wound healing properties, as shown in vivo and by histopathological studies. This study also demonstrates that the thermoresponsive hydrogel was successful as an antibacterial and burned wound-healing transdermal drug delivery system.