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Nano Research 2020年第3期13卷 775-784页

作者： ngoc minh tran Soeun Jung Hyojong Yoo Department of Materials Science and Chemical Engineering Hanyang UniversityAnsanGyeonggi-do15588Republic of Korea

Advanced hybrid nanomaterials(nanohybrids)with unique tailored morphologies and compositions have been used for the target-oriented catalysts due to the structural or supportive properties of each moiety and the synergistic properties of the individual *** rational design and development of nanohybrids by integrating highly porous silica into a nano metal-organic framework(NMOF)are expected to enable unique nanospace engineering in the resulting systems to optimize their utility in the target ***,we report the design and fabrication of advanced nanohybrids composed of dendritic fibrous nanosilica(DFNS)and DFNS/gold(DFNS/Au)hybrids as the core and zinc-based NMOF(Zn-NMOF)as the shell(DFNS@Zn-NMOF)through a solution-based *** combined fibrous morphology of DFNS and micropores of NMOF can be directly employed for nanospace engineering in the resulting multi-compositional and hierarchical systems in a controllable *** DFNS/Au dots@Zn-NMOF nanohybrid shows improved catalytic performance in the Knoevenagel condensation reaction,attributed mainly to the cooperative effect stemming from the suitably organized configurations of each component.

关键词： nanohybrids nanospace engineering dendritic fibrous nanosilica nano metal-organic framework cooperative catalytic performance

Fabrication of zinc-based coordination polymer nano-cubes and post-modification through copper decoration

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Nano Research 2018年第11期11卷 5890-5901页

作者： ngoc minh tran Hien Duy Mai Hyojong Yoo Department of Chemistry Hallym University Chuncheon Gangwon-do 24252 Republic of Korea

Coordination polymer particles (CPPs) with a high degree of porosity and multi-functional reaction sites are promising for diverse applications. The integration of open sites favorable for the post-modification of CPPs presents a unique opportunity for the rational design of inorganic materials with target-oriented functions. Herein, we report a shape-controllable synthetic protocol for zinc-based coordination polymer nanocubes (Zn-CPNs). In the synthesis, 2,6-bis[(4-carboxyanilino)carbonyl] pyridine ([N3]) ligand is employed as an efficient shape-directing modulator to control the size and shape of Zn-CPNs. More importantly, the [N3] ligand provides metal binding sites suitable for the decoration of other functional metals such as copper ions. The copper-modified Zn-CPNs (Cu_Zn-CPNs) show good activities in a heterogeneous catalytic reaction.

关键词： zinc-based coordination polymer nanocubes shape-directing modulator size and shape controls post-modification heterogeneous catalytic reaction

Building the ARIMA Model for Forecasting the Production of Vietnam’s Coffee Export

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Journal of Applied Mathematics and Physics 2024年第4期12卷 1237-1246页

作者： Duy Quang Phung Quoc Thang Trinh Quang Truong Do Ngan Giang Nguyen Van Ha Nguyen Gia Khiem Ngo Thi minh ngoc tran Faculty of Technology and Data Science Foreign Trade University Hanoi Vietnam School of Economics and International Business Foreign Trade University Hanoi Vietnam

Coffee is a significant industry, accounting for 3% of Vietnam’s GDP, with annual export turnover consistently exceeding USD 3 billion. Despite global economic challenges affecting purchasing power at various times, Vietnam’s coffee exports in December 2023 continued to surge, reaching the highest level in the past 9 months at 190,000 tons, a 59.3% increase compared to November 2023, but still a slight 3.5% decrease from the same period last year. The export turnover reached USD 538 million, a 51% increase from November 2023 and a 26.4% increase from the same period last year. Therefore, forecasting the coffee export volume holds significant importance for coffee producers nationwide. This research employs the Box-Jenkins method to construct an ARIMA model for forecasting Vietnam’s coffee export volume based on annual data published by the General Statistics Office. Results indicate that among the models considered, the ARIMA(1, 1, 2) model is the most suitable. The study also provides short-term forecasts for Vietnam’s coffee export volume. However, the current model is limited to forecasting and is not yet optimized, as the assumed linearity in the model is a simplification.

关键词： ARIMA Forecasting Coffee Export Volume Data Science

BTEX pollution caused by motorcycles in the megacity of HoChiminh

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Journal of Environmental Sciences 2013年第2期25卷 348-356页

作者： tran Thi ngoc Lan Pham Anh minh University of Science Vietnam National University227 Nguyen Van CuHoChiMinh 70000Vietnam

Monitoring of benzene, toluene and xylenes （BTEX） was conducted along with traffic counts at 17 roadside sites in urban areas of HoChiminh. Toluene was the most abundant substance, followed by p,m-xylenes, benzene, o-xylene and ethylbenzene. The maximum observed hour-average benzene concentration was 254 μg/m3 . Motorcycles contributed to 91% of the traffic fleet. High correlations among BTEX species, between BTEX concentrations and the volume of on-road motorcycles, and between inter-species ratios in air and in gasoline indicate the motorcycle-exhaust origin of BTEX species. Daily concentrations of benzene, toluene, ethylbenzene, p,m-xylenes and o-xylene were 56, 121, 21, 64 and 23 μg/m 3 , respectively. p,m-xylenes possess the highest ozone formation potential among the BTEX family.

关键词： air pollution benzene BTEX HoChiminh motorcycle exhaust

Kriging-based reliability analysis of the long-term stability of a deep driftconstructed in the Callovo-Oxfordian claystone

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第5期13卷 1033-1046页

作者： ngoc-Tuyen tran Duc-Phi Do Dashnor Hoxha minh-ngoc Vu Gilles Armand Univ.Orléans Univ.ToursINSA CVLLaméEA 7494France Andra R&D Division92298Chatenay-MalabryFrance

Callovo-Oxfordian(COx)claystone has been considered as a potential host rock for geological radioactive waste disposal in France(Cigéo project).During the exploitation phase(100 years),the stability of drifts(***/alveoli)within the disposal is assured by the liner,which includes two layers:concrete arch segment and compressible *** latter exhibits a significant deformation capacity(about 50%)under low stress(<3 MPa).Although the response of these underground structures can be governed by complex thermo-hydro-mechanical coupling,the creep behavior of COx claystone has been considered as the main factor controlling the increase of stress state in the concrete liner and hence the long-term stability of ***,by focusing only on the purely mechanical behavior,this study aims at investigating the uncertainty effect of the COx claystone time-dependent properties on the stability of an alveolus of Cigéo during the exploitation *** describe the creep behavior of COx claystone,we use Lemaitre’s viscoplastic model with three parameters whose uncertainties are identified from laboratory creep *** the reliability analysis,an extension of a well-known Kriging metamodeling technique is proposed to assess the exceedance probability of acceptable stress in the concrete liner of the *** open-source code Code_Aster is chosen for the direct numerical evaluations of the performance *** Kriging-based reliability analysis elucidates the effect of the uncertainty of COx claystone on the long-term stability of the concrete ***,the role of the compressible material layer between the concrete liner and the host rock is also highlighted.

关键词： Reliability analysis Kriging metamodeling Time-dependent behavior Compressible material Callovo-Oxfordian(COx)claystone Long-term stability

Evaluation of the calibration factors of neutron dose rate meters in a 241Am–Be neutron field

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Nuclear Science and Techniques 2019年第9期30卷 18-23页

作者： Thiem ngoc Le Sy minh Tuan Hoang Quynh ngoc Nguyen Hoai-Nam tran Institute for Nuclear Science and Technology VINATOM 179 Hoang Quoc Viet Hanoi Vietnam Institute of Fundamental and Applied Sciences Duy Tan University Ho Chi Minh City Vietnam

Calibrations were performed for three types of neutron ambient dose equivalent rate meters, i.e., Aloka TPS-451C (Hitachi), KSAR1U.06 (Baltic Scientific Instruments), and Model 12-4 (Ludlum), using a standard field of a 241Am–Be source. The measured total neutron ambient dose equivalent rates, H*(10)' tot, were analyzed to obtain the direct neutron ambient dose equivalent rates, H*(10)' dir, using the ISO 8529-2-recommended generalized- fit method, semiempirical fit method, and reducedfitting method (RFM) fit methods. The calibration factor (CF), defined as the ratio between the conventional true value of the neutron ambient dose equivalent rates in a free field, H*(10)' FF, and H*(10)' dir, was evaluated as one of the important characteristics of the neutron meters in the present work. The fitting results show that the H*(10)' dir values of the meters are in good agreement within the theoretical data within 4%. The averaged CFs of the three neutron meters were evaluated as 0:99 ± 0:01, 1:00 ± 0.03;and 0:99 ± 0:08, respectively. The largest standard uncertainty of these values was determined to be approximately 18.47%(k =1). The standard uncertainty of the CFs obtained using the RFM method was less than 4.23%(k=1), which is the smallest uncertainty among the three methods.

关键词： Neutron meter Calibration factor ^241 Am–Be source

Fabrication and Characterization of Multi-layer Heat Mirror with Photocatalytic Properties

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Chinese Physics Letters 2009年第11期26卷 152-155页

作者： tran Le Tuan tran Huu Chi Nguyen Dac ngoc Son Luu minh Nam Hoang Dinh Quan Nguyen Department of Applied Physics College of Natural Science National University of He Chi Mirth City 227 Nguyen Van Cu District 5 Ward 4 He Chi Minh City Vietnam Department of Chemical Engineering College of Technology National University of He Chi Minh City 168 Ly Thuong Kiet District 10 Ho chi Minh City Vietnam

A novel TiO2（5）/TiO2（buffer）/Ti（4）/Ag（3）/Ti（2）/TiO2（1） multi-layer film coating with corning glass is designed and fabricated by a dc magnetron sputtering method as a renovation of the well-known TiO2/Ti/Ag/Ti/TiO2 system in order to obtain a heat mirror system with photocatalytic properties due to sufficient thickness of the Ti02 layer. The outer TiO2 layer is fabricated in two steps, possibly claimed as two layers TiO2（5） and TiO2（buuer）, among which TiO2（buffer） the 70-nm-thick layer deposited in poor oxygen effectively minimizes the oxidation toward its neighbor Ti（4） layer. The optimal total thickness of the TiO2（5） and TiO（buffer） di-layer is found to be 300nm to yield a highly photo-catalytic property of the film without affecting the optical properties considerably. This multi-layer film can transmit light of above 75-85% in the visible spectrum （380 ≤ λ≤ 760 nm） and reflect radiation of above 90% in the infrared spectrum （ λ≥760 nm）. Such multi-layer coatings are strongly recommended not only as promising transparent heat mirrors but also as photo-catalytic films for architectural window coatings.

关键词： Condensed matter: electrical magnetic and optical Surfaces interfaces and thin films Chemical physics and physical chemistry

Sediment transport trends and cross-sectional stability of a lagoonal tidal inlet on the Central Coast of Vietnam

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International Journal of Sediment Research 2019年第4期34卷 322-334页

作者： Do minh Duc tran Thanh Tung Patrick Mc Laren tran ngoc Anh Dinh Thi Quynh Faculty of Geology VNU University of Science Vietnam National University Faculty of Marine and Coastal Engineering Thuyloi University Sed Trend Analysis Limited 4. Faculty of Meteorology Hydrology and Oceanography VNU University of Science Vietnam National University

Lagoonal tidal inlets are a typical morphology of the Central Coast of Vietnam. Recently, navigation channels in these inlets have become increasingly threatened by siltation. This study analyses the relations between sediment distribution and transport trends(using the technique of Sediment Trend Analysis-STAs) in the lagoonal system of the De Gi inlet and then proposes appropriate countermeasures against sand deposition in the navigation channel. The STA identified three types of transport trends in the De Gi inlet, namely dynamic equilibrium, net accretion, and net erosion. Processes associated with the tidal prism have resulted in trends of sediment transport and deposition across the flood and ebb tidal shoals, which maintain a present cross-sectional area of about 1000 m~2. However, longshore sediment transport from north to south resulting from northeast waves cause additional sand deposition in the channel. In addition, the effects of refraction associated with a nearby headland and jetty also increase sedimentation. These processes provide the main reasons for sediment deposition in the De Gi inlet. Short term and regular dredging helps to maintain the navigation channel. A system comprised of three jetties(north, south, and weir) is necessary to ensure the longterm cross-sectional stability of the navigation channel.

关键词： Lagoon Tidal inlet Sediment Trend Analysis (STA) Tidal prism Cross-sectional stability

Random vibration analysis of FGM plates subjected to moving load using a refined stochastic finite element method

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Defence Technology（防务技术） 2024年第4期34卷 42-56页

作者： ngoc-Tu Do Trung Thanh tran Faculty of Mechanical Engineering Hanoi University of IndustryHanoiViet Nam Faculty of Mechanical Engineering Le Quy Don Technical UniversityHanoiViet Nam

The article introduces a finite element procedure using the bilinear quadrilateral element or four-node rectangular element(namely Q4 element) based on a refined first-order shear deformation theory(rFSDT) and Monte Carlo simulation(MCS), so-called refined stochastic finite element method to investigate the random vibration of functionally graded material(FGM) plates subjected to the moving *** advantage of the proposed method is to use r-FSDT to improve the accuracy of classical FSDT, satisfy the stress-free condition at the plate boundaries, and combine with MCS to analyze the vibration of the FGM plate when the parameter inputs are random quantities following a normal distribution. The obtained results show that the distribution characteristics of the vibration response of the FGM plate depend on the standard deviation of the input parameters and the velocity of the moving ***, the numerical results in this study are expected to contribute to improving the understanding of FGM plates subjected to moving loads with uncertain input parameters.

关键词： FGM Moving load R-FSDT Q4 element Monte Carlo simulation Random vibration

Prevalence and outcomes of neonates with severe COVID-19:An observational study at Children’s Hospital 1 in Ho Chi minh City,Vietnam

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Asian Pacific Journal of Tropical Medicine 2024年第9期17卷 392-399,I0001页

作者： Phung Nguyen The Nguyen tran Thanh Thuc Nguyen Thanh Hung Ngo ngoc Quang minh Dang Quoc Duy tran minh Nhut Nguyen Hoang Dung tran Nguyen Ai Nuong Dinh Nguyen Cam Tu Department of Pediatrics University of Medicine and Pharmacy at Ho Chi Minh cityHo Chi Minh CityVietnam Children’s Hospital 1 Ho Chi Minh CityVietnam Pediatric Department School of MedicineVietnam National University Ho Chi Minh CityVietnam

Objective:To evaluate the impact of the severe COVID-19 pandemic on neonates and develop strategies to improve their ***:We conducted an observational cross-sectional study at Children's Hospital 1(CH1)from July 25,2021,to May 31,*** neonates who had fever or respiratory symptoms or were born from mothers with COVID-19 and had a positive RT-PCR SARS-CoV-2 result would be *** classified neonates with COVID-19 into 2 groups:mild/moderate and severe for *** between groups were analyzed using Fisher's exact test/Chi-square test for categorical variables and Student's t-test/Wilcoxon Rank Sum test for continuous ***:This study included 88 newborns who had positive RT-PCR SARS-CoV-2 *** severity COVID-19 rate among neonatal cases was found to be 13.6%(12/88),with a corresponding mortality rate of 1.1%(1/88).All severe cases showed lung abnormalities as evident on chest X-ray *** addition to respiratory symptoms,a higher incidence of gastrointestinal manifestations,such as vomiting and diarrhea,was observed in the severe group,indicating a compelling *** administration of anticoagulant and anti-inflammatory drugs in the study group resulted in a satisfactory outcome with no significant ***:The COVID-19 pandemic has had a substantial impact on the well-being of *** management of COVID-19 in this population presents significant challenges.

关键词： COVID-19 Neonate Anti-inflammatory Anticoagulant