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Enhanced catalytic performance of Cr-inserted hydrotalcites in the liquid oxidation of styrene
Nguyen Tien Thao,Le Thi Kim Huyen 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.73 No.-
Chromium(III) ions were inserted in magnesium hydroxide layers via co-precipitation route. In the low-chromium content sample, Cr(III) ions are present mostly at octahedral sites of metal hydroxide layers,while some Cr(VI) species formed on the external surface of the high-chromium content catalyst. The Cr-doped metal hydroxide layer ions play as active sites for the oxidation of styrene with H2O2 at a lowtemperature. The insertion of chromium(III) in the brucite-like sheets enhanced catalytic stability ofcatalysts in the oxidation of styrene. The Cr-doped hydrotalcites showed a good activity (50–60%), andhigh selectivity to benzaldehyde (80–85%) at room temperature.
Loc My Thi Nguyen,Tien-Trung Nguyen,Thanh Thi Nghiem,Hien Thu Thi Le,Thao Phuong Thi Trinh,Thuan Van Pham,Thanh Chi Nguyen,Linh Khanh Hoang,Trung Tran 한국과학학술지편집인협의회 2020 Science Editing Vol.7 No.1
In the context of the need to ensure appropriate signalling of the publication of high-quality, international-calibre publications in Vietnam, as well as new policies to improve the quality and effectiveness of scientific research in Vietnam, it is practical to investigate the possibility of developing a national open access database (NOAD). This study aims to answer the question of whether it is necessary to establish a NOAD in Vietnam. We used document analysis to evaluate issues related to NOADs. The results of this study show the complexity, lack of consistency, and difficulty in obtaining practical statistics and assessing research and scientific records in Vietnam today. Furthermore, the findings of this study imply that it is necessary to establish a NOAD of scientific research in Vietnam. The information in this report can be used to develop a NOAD for Vietnam in particular, and for any country that lacks one in general.
Hong Khanh Dieu Nguyen,Toan Dang Nguyen,Dung Ngoc Hoang,Duc Sy Dao,Thao Tien Nguyen,Limphirat Wanwisa,Lan Linh Hoang 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.2
Hydrotalcite-like compound containing metal cations such as Mg2+, Al3+ and Ni2+ was characterized using Ni K-edge EXAFS and in situ Ni K-edge XANES techniques for clarifying its bonding environment around Ni2+ sites and structure changes during calcination from room temperature to 550 oC, respectively. At the fixed molar ratio of Mg/Ni/Al of 2/1/1, the results obtained from EXAFS analysis showed a slight blue shift before and after the calcination at 550 oC and a reduction in white line peak; the best fits of the two samples revealed tiny change in coordination number about 7 for Ni-O path but considerable difference for Ni-Mg(Al) path from about 4.5 to 9.5, confirming a modification from brucite like to mixed oxide structure. On the other hand, bond distances of the Ni-O and Ni-Mg paths nearly fixed at about 2.06 Å to 3.0 Å reflected stability of the cationic bond order on each plane, but partial collapse and decomposition of the interlayer formed by water molecules and anion CO3 2− after the calcination. Linear combination fit extracted from the in situ Ni K-edge XANES also confirmed the changes along with the calcination such as slow and fast decreases of brucite fraction at 150 oC and 330 oC, respectively, in corresponding to the mixed oxide fraction increases. The achieved bonding structures were also applied to explain acid-base occurrence of the hydrotalcite-like material, especially the acid sites generated by different static charges along with the bonds. The explanation was illustrated by NH3-TPD method.
Nguyen Thanh Tien,Pham Thi Bich Thao,Le Tuan 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.64 No.11
We propose a modification of the interface roughness (IFR) scattering form factor in intersubbandtransitions. We properly derived a formula for the form factor for IFR scattering in terms of theintegrals of the envelope wave functions. This new form factor has a more global natural than theold one (proposed by Ando) and may be suitable for a wide range of applications. In this paper,we calculate and compare the absorption linewidths by applying of the old form factor and thenew one. Different from previous calculations, for the same surface profile (, ), the interfaceroughness scattering absorption linewidth calculated with the new form factor is twice as great asthat calculated with the old one. Our numerical calculations may better explain the experimentalresults for the well-width dependence of the intersubband absorption linewidth.
Tien Duong Vu,Hyung-Jeong Yang,Luu Ngoc Do,Thao Nguyen Thieu 한국스마트미디어학회 2016 스마트미디어저널 Vol.5 No.1
In recent decades, the study of human brain function has dramatically increased thanks to the advent of Functional Magnetic Resonance Imaging. This is a powerful tool which provides a deep view of the activities of the brain. From fMRI data, the neuroscientists analyze which parts of the brain have responsibility for a particular action and finding the common pattern representing each state involved in these tasks. This is one of the most challenges in neuroscience area because of noisy, sparsity of data as well as the differences of anatomical brain structure of each person. In this paper, we propose the use of appropriate discriminant methods, such as Fisher Discriminant Ratio and hypothesis testing, together with strong boosting ability of Adaboost classifier. We prove that discriminant methods are effective in classifying cognitive states. The experiment results show significant better accuracy than previous works. We also show that it is possible to train a successful classifier without prior anatomical knowledge and use only a small number of features.
Recovering Incomplete Data using Tucker Model for Tensor with Low-n-rank
Thao Nguyen Thieu,Hyung-Jeong Yang,Tien Duong Vu,Sun-Hee Kim 한국콘텐츠학회 2016 International Journal of Contents Vol.12 No.3
Tensor with missing or incomplete values is a ubiquitous problem in various fields such as biomedical signal processing, image processing, and social network analysis. In this paper, we considered how to reconstruct a dataset with missing values by using tensor form which is called tensor completion process. We applied Tucker factorization to solve tensor completion which was built base on optimization problem. We formulated the optimization objective function using components of Tucker model after decomposing. The weighted least square matric contained only known values of the tensor with low rank in its modes. A first order optimization method, namely Nonlinear Conjugated Gradient, was applied to solve the optimization problem. We demonstrated the effectiveness of the proposed method in EEG signals with about 70% missing entries compared to other algorithms. The relative error was proposed to compare the difference between original tensor and the process output.
Recovering Incomplete Data using Tucker Model for Tensor with Low-n-rank
Thieu, Thao Nguyen,Yang, Hyung-Jeong,Vu, Tien Duong,Kim, Sun-Hee The Korea Contents Association 2016 International Journal of Contents Vol.12 No.3
Tensor with missing or incomplete values is a ubiquitous problem in various fields such as biomedical signal processing, image processing, and social network analysis. In this paper, we considered how to reconstruct a dataset with missing values by using tensor form which is called tensor completion process. We applied Tucker factorization to solve tensor completion which was built base on optimization problem. We formulated the optimization objective function using components of Tucker model after decomposing. The weighted least square matric contained only known values of the tensor with low rank in its modes. A first order optimization method, namely Nonlinear Conjugated Gradient, was applied to solve the optimization problem. We demonstrated the effectiveness of the proposed method in EEG signals with about 70% missing entries compared to other algorithms. The relative error was proposed to compare the difference between original tensor and the process output.
Vu, Tien Duong,Yang, Hyung-Jeong,Do, Luu Ngoc,Thieu, Thao Nguyen THE KOREAN INSTITUTE OF SMART MEDIA 2016 스마트미디어저널 Vol.5 No.1
In recent decades, the study of human brain function has dramatically increased thanks to the advent of Functional Magnetic Resonance Imaging. This is a powerful tool which provides a deep view of the activities of the brain. From fMRI data, the neuroscientists analyze which parts of the brain have responsibility for a particular action and finding the common pattern representing each state involved in these tasks. This is one of the most challenges in neuroscience area because of noisy, sparsity of data as well as the differences of anatomical brain structure of each person. In this paper, we propose the use of appropriate discriminant methods, such as Fisher Discriminant Ratio and hypothesis testing, together with strong boosting ability of Adaboost classifier. We prove that discriminant methods are effective in classifying cognitive states. The experiment results show significant better accuracy than previous works. We also show that it is possible to train a successful classifier without prior anatomical knowledge and use only a small number of features.
Tran, Phuong Thao,Dat, Nguyen Tien,Dang, Nguyen Hai,Van Cuong, Pham,Lee, Suhyun,Hwangbo, Cheol,Van Minh, Chau,Lee, Jeong-Hyung Elsevier 2019 Phytomedicine Vol.55 No.-
<P><B>ABSTARCT</B></P> <P><B>Background</B></P> <P>Many bone-related diseases such as osteoporosis and rheumatoid arthritis are commonly associated with excessive activity of the osteoclast. Ganomycin I (GMI), a meroterpenoid isolated from Vietnamese mushroom <I>Ganoderma lucidum</I>, possesses a variety of beneficial effects on human health. However, its impact and underlying mechanism on osteoclastogenesis remain unclear. In the present study, we investigated the effect of GMI on RANKL-induced osteoclast formation in mouse BMMs and RAW264.7 cells.</P> <P><B>Methods</B></P> <P>BMMs or RAW264.7 cells were treated with GMI followed by an evaluation of cell viability, RANKL-induced osteoclast differentiation, actin-ring formation, and resorption pits activity. Effects of GMI on RANKL-induced phosphorylation of MAPKs as well as the expression levels of NFATc1 and c-Fos were evaluated by Western blot analysis. Expression levels of osteoclast marker genes were evaluated by Western blot analysis and reverse transcription-qPCR.</P> <P><B>Results</B></P> <P>GMI significantly inhibited RANKL-induced osteoclast differentiation by decreasing the number of osteoclasts, osteoclast actin–ring formation, and bone resorption in a dose-dependent manner without affecting cell viability. At molecular level, GMI inhibited the RANKL-induced phosphorylation of ERK, JNK, and p38 MAPKs, as well as the expression levels of c-Fos and NFATc1, which are known to be crucial transcription factors for osteoclast formation. In addition, GMI decreased expression levels of osteoclastogenesis specific marker genes including c-Src, CtsK, TRAP, MMP-9, OSCAR, and DC-STAMP in RANKL-stimulated BMMs.</P> <P><B>Conclusion</B></P> <P>Our findings suggest that GMI can attenuate osteoclast formation by suppressing RANKL-mediated MAPKs and NFATc1 signaling pathways and the anti-osteoclastogenic activity of GMI may extend our understanding of molecular mechanisms underlying biological activities and pharmacological use of <I>G. lucidum</I> as a traditional anti-osteoporotic medicine.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>