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Journal of Environmental Science and Engineering(B) 2017年第7期6卷 387-390页

作者： Le xuan Hung tran thanh Hoang Vu Ngoc Pi Mechanical Engineering Faculty Thai Nguyen University of Technology Thai Nguyen 23000 Vietnam Center for Technical Practice Thai Nguyen University of Technology Thai Nguyen 23000 Vietnam

Stabilization for Equal-Order Polygonal Finite Element Method for High Fluid Velocity and Pressure Gradient

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Computers, Materials & Continua 2020年第3期62卷 1109-1123页

作者： T.Vu-Huu C.Le-thanh H.Nguyen-xuan M.Abdel-Wahab Department of Electrical energy MetalsMechanical Constructions and SystemsFaculty of Engineering and ArchitectureGhent UniversityGhentBelgium Faculty of Civil Engineering Vietnam Maritime UniversityHai PhongVietnam Faculty of Civil Engineering and Electricity Ho Chi Minh City Open UniversityHo Chi MinhVietnam CIRTech Institute Ho Chi Minh City University of Technology(HUTECH)Ho Chi MinhVietnam Division of Computational Mechanics Ton Duc Thang UniversityHo Chi MinhVietnam Faculty of Civil Engineering Ton Duc Thang UniversityHo Chi MinhVietnam

This paper presents an adapted stabilisation method for the equal-order mixed scheme of finite elements on convex polygonal meshes to analyse the high velocity and pressure gradient of incompressible fluid flows that are governed by Stokes equations *** technique is constructed by a local pressure projection which is extremely simple,yet effective,to eliminate the poor or even non-convergence as well as the instability of equal-order mixed polygonal *** this research,some numerical examples of incompressible Stokes fluid flow that is coded and programmed by MATLAB will be presented to examine the effectiveness of the proposed stabilised method.

关键词： Polygonal finite element method fluid computation stokes equation mixed method local projection

Effect of Poly-Alkylene-Glycol Quenchant on the Distortion, Hardness, and Microstructure of 65Mn Steel

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Computers, Materials & Continua 2021年第6期67卷 3249-3264页

作者： Thi xuan tran xuan Phuong Nguyen Duong Nam Nguyen Dinh Toai Vu Minh Quang Chau Osamah Ibrahim Khalaf Anh Tuan Hoang Hanoi University of Science and Technology HanoiVietnam Ho Chi Minh City University of transport Ho Chi Minh CityVietnam Vietnam Maritime University HaiphongVietnam Industrial University of Ho Chi Minh City(IUH) Ho Chi Minh CityVietnam Al-Nahrain Nanorenewable Energy Research Center Al-Nahrain UniversityBaghdadIraq Ho Chi Minh city University of Technology(HUTECH) Ho Chi Minh CityVietnam

Currently,the 65Mn steel is quenched mainly by oil *** though the lower cooling rate of oil compared to water reduces the hardness of steel post quenching,the deforming and cracking of parts are often *** the other hand,the oil media also has the disadvantage of being ammable,creating smoke that adversely affects the *** poly alkylene glycol(PAG)polymer quenchant is commonly used for quenching a variety of steels based on its advantages such as non-ammability and exible cooling rate subjected to varying concentration and stirring *** article examines the effect of PAG polymer quenching solution(with concentrations of 10%and 20%)on deformation,hardness,and microstructure of C-ring samples made of 65Mn ***,the performance of PAG polymer quenchant is also compared with those of two common quenching solutions:Water and *** cooling in water,the C-ring samples had the largest deformation and 2 times higher than the results obtained when a 10%PAG solution was *** particular,similar levels of deformation on the C-ring samples were observed in both cases of 20%PAG solution and oil as the primary quenching ***,the hardness level measured between the sampled parts quenched in the 20%PAG solution appeared to be more uniform than that obtained from the oil-quenched *** study of the microscopic structure of steel by optical microscopy combined with X-ray diffraction showed that the water hardened sample exhibited cracks and comprised of two phases,martensite and retained *** to the results of Electron Back Scattering Diffraction(EBSD)analysis and backscattering electronic image(BSE),the content of austenite residue in the sample when the sample was cooled in PAG 10 and 20%solution was 3.21%and 4.73%,respectively and smaller than the measurements obtained from oil quenching ***,the 65Mn steel is cooled in 20%PAG solution for high hardness and more evenly distributed than when it is q

关键词： Polyethylene glycol electron backscattering diffraction quenching media cooling rate backscattering electronic image

Effects of the urban heat island and climate change on the growth of Khaya senegalensis in Hanoi,Vietnam

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Forest Ecosystems 2018年第4期5卷 516-529页

作者： Astrid Moser-Reischl Enno Uhl Thomas Rotzer Peter Biber tran van Con Nguyen thanh Tan Hans Pretzsch Chair for Forest Growth and Yield Science Center of Life and Food Sciences WelhenstephanTechnical University MunichHans-Carl-von-Carlowitz-Platz 285354 FreisingGermany Vietnamese Academy of Forest Sciences Dong Ngac CommuneTu Liem DistrictHanoiVietnam Tay Nguyen University 567 Le Duan StreeBuon Ma Thuot CityDak La ProvinceVietnam

Background: Recent projections expect that Vietnam will be affected most severely by climate change with higher temperatures, more precipitation and rising sea levels. Especially increased temperatures will worsen the situations in cities, amplifying the urban heat island effect. Green infrastructures, i.e. urban trees are a common rtool to improve the urban micro-climate for humans. Vital and well growing trees provide greatest benefits such as evaporative cooling, shading, air filtering and carbon storage. However, urban tree growth is often negatively affected by urban growing conditions such as high soil sealing with compacted tree pits providing small growing spaces with limited water, nutrient and oxygen supply, further warm temperatures and high pollution emissions. This study analyzed the growth of urban and rural African mahogany(Khaya senegalensis(Desr.) A. Juss.) trees in the city of Hanoi, Vietnam and the effects of the surrounding climate conditions on tree ***: The results showed that rural African mahogany trees grew better than trees situated in the city center, which is contrary to other results on tree growth of temperate and subtropical cities worldwide. Moreover tree growth was similar regardless of the time of growth. Other results regarding stem growth of African mahogany located in different areas of Hanoi(east, west, north, city center) revealed a better growth in the northern and western outskirts of the city compared to the growth of trees in the city ***: African mahogany trees in the urban centers of Hanoi showed a decreased growth compared to rural trees,which was likely induced by a low ground-water level and high pollution rates. In view of climate change and global warming, the decreased tree growth in the city center may also affect tree service provision such as shading and cooling. Those climate mitigation solutions are strongly needed in areas severely affected by climate change and global warming such as

关键词： African mahogany Dendrochronology Ecosystem services Urban tree growth

A Correlation Coefficient Approach for Evaluation of Stiffness Degradation of Beams Under Moving Load

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Computers, Materials & Continua 2019年第7期61卷 27-53页

作者： thanh Q.Nguyen Thao T.D.Nguyen H.Nguyen-xuan Nhi K.Ngo Laboratory of Applied Mechanics(LAM) Ho Chi Minh City University of TechnologyHo Chi Minh City740030Vietnam Saigon Hi-Tech Park Training Center Ho Chi Minh City715650Vietnam Ho Chi Minh City Department of transportation and Communication Ho Chi Minh City710100Vietnam CIRTECH Institute Ho Chi Minh City University of Technology(HUTECH)Ho Chi Minh City717349Vietnam Department of Physical Therapy Graduate Institute of Rehabilitation ScienceChina Medical UniversityTaichung40402Taiwan

This paper presents a new approach using correlation and cross-correlation coefficients to evaluate the stiffness degradation of beams under moving *** theoretical study of identifying defects by vibration methods showed that the traditional methods derived from the vibration measurement data have not met the needs of the actual *** show that the correlation coefficients allow us to evaluate the degree and the effectiveness of the defects on *** the same time,the cross-correlation model is the basis for determining the relative position of *** results of this study are experimentally conducted to confirm the relationship between the correlation coefficients and the existence of the *** particular,the manuscript shows that the sensitivity of the correlation coefficients and cross-correlation is much higher than the parameters such as changes in stiffness(EJ)and natural frequency values(Δf).This study suggests using the above parameters to evaluate the stiffness degradation of beams by vibration measurement data in practice.

关键词： Correlation coefficient cross-correlation vibration signal vibration amplitude frequency

Thermodynamic Simulation on the Change in Phase for Carburizing Process

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Computers, Materials & Continua 2021年第7期68卷 1129-1145页

作者： Anh Tuan Hoang xuan Phuong Nguyen Osamah Ibrahim Khalaf Thi xuan tran Minh Quang Chau Thi Minh Hao Dong Duong Nam Nguyen Ho Chi Minh city University of Technology(HUTECH) HoVietnam Ho Chi Minh city University of transport Ho Chi Minh cityVietnam Al-Nahrain University Al-Nahrain Nanorenewable Energy Research CenterBaghdadIraq Hanoi University of Science and Technology HanoiVietnam Industrial University of Ho Chi Minh City(IUH) Ho Chi Minh cityVietnam Vietnam Maritime University HaiphongVietnam

The type of technology used to strengthen the surface structure of machine parts,typically by carbon-permeation,has made a great contribution to the mechanical engineering industry because of its outstanding advantages in corrosion resistance and enhanced mechanical and physical ***,carbon permeation is considered as an optimal method of heat treatment through the diffusion of carbon atoms into the surface of alloy *** study presented research results on the thermodynamic calculation and simulation of the carbon permeability *** Fick’s law,the paper calculated the distribution of carbon concentration in the alloy steel after it is absorbed from the surface into the internal of the *** the SYSWELD software,an analysis was performed on the carbon permeability process to determine the distribution of carbon concentrations in 20CrMo steel that was then followed by a detailed analysis of the microstructure of the sample post the carburizing *** to the calculation results,the surface carbon content was 0.9%and steadily decreased into the *** 3 hours,the depth of the absorbent layer was measured at 0.5 mm for both the cylindrical and cubic *** analyzing the phase,the distribution of martensite phases such as ferrite/pearlite and residual austenite was also determined after the carburizing process.

关键词： Carburizing process 20CrMo steel thermodynamic analysis microstructure formation carbon concentration

First Record of Sphenomorphus incognitus (Thompson, 1912) (Squamata: Scincidae) from Vietnam with Some Notes on Natural History

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Asian Herpetological Research 2012年第2期3卷 147-150页

作者： Truong Quang NGUYEN Tung thanh tran Tao Thien NGUYEN Wolfgang BHME Thomas ZIEGLER Institute of Ecology and Biological Resources Vietnam Academy of Science and Technology Present address: Department of Terrestrial Ecology Cologne Biocenter University of Cologne Vinh Phuc College of Education 4. Vietnam National Museum of Nature Vietnam Academy of Science and Technology 5. Zoologisches Forschungsmuseum Alexander Koenig 6. AG Zoologischer Garten Kln

Sphenomorphus incognitus is recorded for the first time outside of China. The new locality record is from the Tay Yen Tu Nature Reserve in Bac Giang Province, northeastern Vietnam at elevations between 200–450 m. Based on the newly collected specimens, we present an expanded description and provide data on the natural history of this species in northern Vietnam.

关键词： new record Sphenomorphus incognitus Tay Yen Tu Nature Reserve Bac Giang Province Vietnam

Effects of lime treatment on the microstructure and hydraulic conductivity of Héricourt clay

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Journal of Rock Mechanics and Geotechnical Engineering 2014年第5期6卷 399-404页

作者： thanh Danh tran Yu-Jun Cui Anh Minh Tang Martine Audiguier Roger Cojean Mines ParisTech-Centre de Géosciences FontainebleauFrance Laboratoire Navier/CERMES Ecole des Ponts ParisTech6 et 8 Avenue Blaise Pascal77455 Marne-la-Vallée Cedex 2France Mines ParisTeche-Centre de Géosciences FontainebleauFrance

This study aims at evidencing the effects of lime treatment on the microstructure and hydraulic conductivityof a compacted expansive clay, with emphasis put on the effect of lime hydration and *** this purpose, evolutions of hydraulic conductivity were investigated for both lime-treatedand untreated soil specimens over 7 d after full saturation of the specimens and their microstructureswere observed at the end. Note that for the treated specimen, dry clay powder was mixed with quicklimeprior to compaction in order to study the effect of lime hydration. It is observed that lime hydration andmodification did not affect the intra-aggregate pores but increased the inter-aggregates pores size. Thisincrease gave rise to an increase of hydraulic conductivity. More precisely, the hydraulic conductivity oflime-treated specimen increased progressively during the first 3 d of modification phase and stabilisedduring the next 4 d which correspond to a short period prior to the stabilisation phase. The microstructureobservation showed that stabilisation reactions took place after 7 d. Under the effect of stabilisation,a decreasing hydraulic conductivity can be expected in longer time due to the formation ofcementitious compounds. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.

关键词： Clays Lime hydration Hydraulic conductivity Microstructure Temperature effect

Nutritional status of Vietnamese infants assessed by Fenton growth chart and related factors:A cross-sectional study

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Pediatric Investigation 2023年第4期7卷 254-262页

作者： Lieu Thu Thi Nguyen Cuong Danh tran Ha Thu Thi Nguyen Hai thanh Phan Linh Thuy Nguyen Huong Lan Thi Nguyen Anh Hoai Thi Ta Chau Quynh Thi Pho Khanh Nam Do Anh Kim Dang Huong Thi Le School of Preventive Medicine and Public Health Hanoi Medical UniversityHanoiVietnam Department of Nutrition National Hospital of Obstetrics and GynecologyHanoiVietnam Department of General Obstetrics National Hospital of Obstetrics and GynecologyHanoiVietnam Department of Nutrition and Dietetics Hanoi Medical University HospitalHanoiVietnam Queensland Alliance for Environmental Health Sciences(QAEHS) The University of QueenslandBrisbaneAustralia

Importance:Nutritional status of infants,measured by birth weight and length,is an essential factor in neonatal *** in newborns may lead to a higher risk of mortality,neurological and cognitive impairment,and poor language ***:This study aims to assess the nutritional status of infants and related factors regarding maternal anthropometric characteristics and medical ***:A cross-sectional study was conducted at the National Hospital of Obstetrics and Gynecology,Vietnam from May 2021 to May 2022 on 340 infants and *** birth weight was defined following the Intergrowth-21 *** was evaluated using the Fenton growth chart when the length was below the 10%percentile line of the gestational *** regression models were applied to identify factors associated with the nutritional status of ***:We found that 12.4%and 14.1%of infants in our study fell into stunted and underweight categories,*** of mothers over 35 years old,having a height lower than 150 cm or experiencing anemia during pregnancy were more likely to be stunted or have low birth *** albumin deficiency during pregnancy was strongly associated with the infant being underweight(odds ratio[OR]=2.8,95%confidence interval[95%CI]1.1–7.3).Newborns were more likely to be stunted if their mothers had a history of preterm birth(OR=3.3,95%CI 1.1–10.2).Interpretation:Maternal nutritional status is closely related to infant malnutrition,particularly in preterm *** the understanding of mothers regarding prenatal care,reproductive healthcare,adequate nutritional diet,and multi-micronutrient supplements during pregnancy is therefore important.

关键词： Fenton chart Infant Low birth weight Stunting Underweight

Association between the Phenotypes and Genotypes of Antimicrobial Resistance in Haemophilus parasuis Isolates from Swine in Quang Binh and Thua Thien Hue Provinces, Vietnam

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Engineering 2020年第1期6卷 40-48页

作者： Chao Nguyen Van Lijun Zhang Tam Vu Thi thanh Hung Pham Hoang Son Tuan tran Ngoc Qi Huang Rui Zhou State Key Laboratory of Agricultural Microbiology College of Veterinary MedicineHuazhong Agricultural UniversityWuhan 430070China Faculty of Animal Science and Veterinary Medicine University of Agricultural and ForestryHue UniversityHue 53000Vietnam Mientrung Institute for Scientific Research Vietnam Academy of Science and TechnologyHue 53000Vietnam Guangdong Provincial Key Laboratory of Marine Biology Shantou UniversityShantou 515063China Cooperative Innovation Center of Sustainable Pig Production Wuhan 430070China International Research Center for Animal Diseases The Ministry of Science and TechnologyWuhan 430070China

Haemophilus parasuis (H. parasuis) is one of the bacterial pathogens of great concern as it causes huge economic losses to the swine industry worldwide. One of the reasons why the control of H. parasuis has failed is the increase in antimicrobial resistance (AMR). The country of Vietnam has the second-largest pig production in Asia. However, there is still a lack of data about the AMR prevalence of H. parasuis in *** purpose of this study is to investigate the prevalence of AMR and analyze the association between AMR and AMR genes (ARGs). The H. parasuis strains used in this research were isolated from swine in the Quang Binh and Thua Thien Hue Provinces, Central Vietnam, as reported in our previous study. All of the strains were tested for AMR against 25 antibacterial agents using the broth microdilution method and for the presence of ARGs using the polymerase chain reaction (PCR) method. The tested strains were shown to have a high frequency of resistance to trimethoprim/sulfamethoxazole (94.6%), followed by resistance to colistin, chloramphenicol, gentamicin, penicillin, lincomycin, and amoxicillin. The most prevalent ARGs in these strains were blaTEM-1 (94.6%), int (76.8%), gyrA (58.9%), and rmtD (50.0%). Cefuroxime, chloramphenicol, and tobramycin resistances were strongly correlated with the presence of the ARGs blaROB-1 (odds ratio (OR) = 26.3, 95% confidence interval (CI) 2.7–255.7, p = 0.002), catl (OR = 25.1, 95% CI 2.4–258.9, p = 0.004), and strB (OR = 23.5, 95% CI 2.6–212.6, p = 0.001), *** study reveals for the first time the current situation of H. parasuis AMR in Central Vietnam, which is helpful for the clinical control of this disease, as well as for the development of policies and clinical practice guidelines to reduce AMR in swine production in Central Vietnam.

关键词： Haemophilus parasuis Antimicrobial resistance Antimicrobial resistance gene Vietnam