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Advances in Applied Mathematics and Mechanics 2023年第2期15卷 468-484页

作者： Dang Thuy Dong Nguyen Thi Phuong vu hoai Nam Le Ngoc Ly Nguyen Van Tien vu Minh Duc Tran Quang Minh vu Tho Hung Nguyen Thi Huong Giang Faculty of Civil Engineering University of Transport TechnologyHanoi 100000Vietnam Graduate School of Advanced Science and Engineering Hiroshima University1-4-1 KagamiyamaHigashi-HiroshimaHiroshima 739-8527Japan Faculty of Fundamental Science for Engineering University of Transport TechnologyHanoi 100000Vietnam

The main aim of this paper is to present an analytical approach on the postbuckling for torsionally loaded sandwich carbon nanotube(CNT)reinforced cylindrical shells with the auxetic *** considered shells consist of three layers,external and internal CNT reinforced layers,and the auxetic lattice core made by isotropic *** homogenization model for honeycomb auxetic lattice core is utilized,and the equilibrium equations are formulated based on the nonlinear Donnell’s thin shell theory with von Karman geometrical *** three terms of deflection are considered,the Airy’s stress function and Galerkin’s method are utilized,the explicit expression of critical buckling of torsionally loaded shells and load-deflection expression of postbuckling states are *** effects of two carbon nanotube reinforced layers,the auxetic core layer,the volume fraction of carbon nanotube on the torsional buckling behavior are examined and remarked.

关键词： Nonlinear postbuckling carbon nanotube reinforced composite cylindrical shell torsion auxetic core

Some Optical, Electrical Properties of Lead Free KNN-CZN Ceramics

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Journal of Materials Science and Chemical Engineering 2020年第7期8卷 1-11页

作者： Phan Dinh Gio Truong Thanh Bau Ngo vu hoai Nguyen Quoc Nam Department of Physics University of Sciences Hue University Hue Vietnam

Lead free (1−x)K0.5Na0.5NbO3-xCa(Zn1/3Nb2/3)O3 (abbreviated KNN-xCZN) ferroelectric ceramics, with x = 0, 0.02, 0.04, 0.06, 0.08, 0.10, have been fabricated by the conventional solid-state reaction method. The effects of CZN content on the structure, microstructure and some optical, electrical properties of KNN-xCZN ceramics were studied in detail. The experimental results showed that the crystal structure of ceramics gradually transformed from orthorhombic phase into pseudo-cubic phase with doping of xCa(Zn1/3Nb2/3)O3. With increasing of the CZN concentration, the ceramic density increased and reached the highest value (4.29 g/cm3) at x = 0.08 mol, besides, the grain size of the ceramics decreased gradually, the microstructure more uniform, the grains are packed with clear grain boundaries, fewer pores, especially at x = 0.08 mol. With the dense and fine-grained microstructures, the optical transmission of the ceramics is strong, the ceramic sample with x = 0.08 mol exhibits stably high transmittance above 60% in the visible spectrum and the largest optical band gap energy (Eg = 3.0 eV) was obtained. The Curie temperature (TC) decreases when the concentration of CZN increases. The broadness of dielectric peaks around Tm indicated a diffusive phase transition for all compositions suggesting the relaxor-like behavior of KNN-xCZN ceramic systems.

关键词： Microstructure Optical Property Dielectric Ferroelectric KNN-xCZN

Evaluation of Interaction between Surface Water and Groundwater in the South of Hanoi City by Stable Isotope Technique

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Journal of Environmental Protection 2022年第11期13卷 870-880页

作者： Vo Thi Anh Tran Khanh Minh Ha Lan Anh Mai Dinh Kien vu hoai Dang Duc Nhan Institute for Nuclear Science and Technology Hanoi Vietnam

The δ18O and δ2H stable isotope techniques for studying properties of groundwater and surface help us to understand more clearly about the distribution and movement of groundwater in the South of Hanoi area. There were 68 water samples from the studying area and analyzed by a Liquid Water Isotope Analyzer (LWIA-24D). The stable isotope values of the groundwater from Pleistocene aquifers were range from -3.21‰ to -9.55‰ δ18O and -35.32‰ to -67.44‰ δ2H;rainwater from -8.18‰ to -4.13‰ δ18O and -61.19‰ to -17.93‰ δ2H;Red river water from -7.51‰ to -5.29‰ δ18O and -51.60‰ to -38.99‰ δ2H. Based on stable isotope characteristics, the results show that there was a relationship between surface water and groundwater in the South of Hanoi city. It is that groundwater recharges for river water in the dry season with 74%, and in the rainfall season groundwater is recharged from river with 87%.

关键词： Stable Isotopes Groundwater Surface Water River Water Precipitation Recharge

Using Isotope Technology for Surface Water Environment Research in Southern Hanoi

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Journal of Environmental Protection 2016年第8期7卷 1113-1118页

作者： Vo Thi Anh Tran Khanh Minh Trinh Van Giap Ha Lan Anh Nguyen Thanh Cong Nguyen Hong Thinh vu hoai Institute for Nuclear Science and Technology Hanoi Vietnam Vinh University Vinh Vietnam

The surface water in the southern of Hanoi capital is researched by identifying δ2H and δ18O stable isotopes together with EC, DO, BOD5, COD, TSS. Surface water samples for studying include the Red river, Nhue river and Kim Nguu river, Thanh Nhan lake, Yen So lake and Van Quan lake were collected in the dry season (April) and the rainy season (August) in 2015. The stable isotope analysis results showed that the δ18O values is a range from -42.53‰ to -64.05‰ and, the δ2H values is the range from -5.09‰ to -8.79‰ under global meteoric waterline (in the water vapor region). The δ2H results of the rivers and lakes in the dry season are more negative than the rainy season with a small difference. The δ18O results of lakes in the dry season are more negative than the rainy season, but the δ18O results of river in the dry season are more positive than the rainy season. The results of the EC, BOD, COD, DO, TSS analysis showed that surface water environment has changed clearly in the two seasons and the contamination level in the dry season is usually higher than the rainy season. The lakes and rivers strongly influenced by human activities led to seriously pollution are Van Quan lake and Yen So lake, Nhue river and Kim Nguu river.

关键词： Isotope Technology Surface Water Quality Change in Difference Seasons

Study the Changes in Soil Organic Carbon of Rice-Maize Cropping System in the Top Layer of Alluvisol Soil in Dan Phuong: A Study of C-13 Stable Isotope Composition (<i>δ</i><sup>13</sup>C)

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Journal of Environmental Protection 2019年第10期10卷 1361-1372页

作者： Nguyen Thi Hong Thinh vu hoai Ha Lan Anh Vo Thi Anh Truong Viet Chau Trinh Van Giap Tran Minh Tien Isotope Hydrology Laboratory Institute for Nuclear Science and TechnologyHanoiVietnam Soils and Fertilizers Research Institute HanoiVietnam

In this study, the experiments on field were conducted to examine the change in the content of soil organic carbon (SOC), its C-13 stable isotope composition (δ 13C) and some main physical, chemical parameters (soil moisture, pH, soil density, content of humic, fulvic, total N, total P, total K) in alluvial soil of Dan Phuong region—Vietnam at a depth of 0 - 30 cm when we changed the regime from 2 maize -1 rice crop to 2 rice - 1 maize crop per 1 year. In addition to analyzing the main parameters in soil, C content and its δ 13C value in parts of rice and maize (root, stem and leaf) were also analyzed to assess the contribution of plant residues on soil organic carbon content after harvest. The experiment was carried out in 2016-2017 on the field with the traditional farming method of local farmers along with the tropical monsoon weather conditions of the North-Vietnam. The results showed that SOC had positive correlation with total N, total P parameters and negative correlation with δ 13C values of soil samples at two layers (0 - 15 cm and 15 - 30 cm). The average of total dry biomass (stem, stump + roots and leaf parts) per 1 rice and 1 maize crop was 10.64 Mg/ha and 9.09 Mg/ha, respectively. The average of δ 13C value of rice (C3 plant) was -29.78‰ and its value of maize (C4 plant) was -12.61‰. The new plant (rice) contributes to the total soil organic carbon content from 11.31% to 44.14% at the 0 - 15 cm layer and from 6.55% to 11.31% at the 15 - 30 cm layer in one-year experiment period.

关键词： Soil Organic Carbon (SOC) C-13 Stable Isotope Maize and Rice Crop Soil Properties

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液压制动试验台机械系统的分析

机械设计与制造 2015年第8期 1-3,8页

作者：武氏怀秋宋锦春东北大学机械工程与自动化学院辽宁沈阳110819

火车液压制动试验台的制作目的是为了检测液压技术制动的可行性。火车液压制动试验台包括两主要系统:液压系统和机械系统。在这介绍机械系统的设计与分析。为了能够更加精确地确定上述试验台机械部分设计的实用性,即其的强度,刚度,抗变... 详细信息

火车液压制动试验台的制作目的是为了检测液压技术制动的可行性。火车液压制动试验台包括两主要系统:液压系统和机械系统。在这介绍机械系统的设计与分析。为了能够更加精确地确定上述试验台机械部分设计的实用性,即其的强度,刚度,抗变形的的能力是否能够满足试验台的正常工作的要求。作者采用现在分析能力最好的有限元分析软件ANSYS对试验台中的零件的结构,强度,变形等进行分析,以确定它们的性能,从而再加工成实物前确定该设计的可靠性以及可行性。

关键词：液压制动机械系统试验台静力学的分析 ANSYS分析软件

An isogeometric analysis approach for dynamic response of doubly-curved magneto electro elastic composite shallow shell subjected to blast loading

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Defence Technology（防务技术） 2024年第11期41卷 159-180页

作者： Pham Hoang Tu Tran Van Ke vu Khac Trai Le hoai Faculty of Automotive Engineering School of TechnologyVan Lang UniversityHo Chi Minh City 700000Viet Nam Faculty of Mechanical Engineering Le Quy Don Technical UniversityHanoi 100000Viet Nam Faculty of Engineering and Technology Nguyen Tat Thanh UniversityHo Chi Minh City 700000Viet Nam HUTECH Institute of Engineering HUTECH UniversityHo Chi Minh City 700000Viet Nam

For the first time, the isogeometric analysis(IGA) approach is used to model and analyze free and forced vibrations of doubly-curved magneto-electro-elastic(MEE) composite shallow shell resting on the visco-Pasternak foundation in a hygro-temperature environment. The doubly-curved MEE shallow shell types include spherical shallow shell, cylindrical shallow shell, saddle shallow shell, and elliptical shallow shell subjected to blast load are investigated. The Maxwell equation and electromagnetic boundary conditions are used to determine the vary of the electric and magnetic potentials. The MEE shallow shell's equations of motion are derived from Hamilton's principle and refined higher-order shear theory. Then, the IGA method is used to derive the laws of natural frequencies and dynamic responses of the shell under various boundary conditions. The accuracy of the model and method is verified through reliable numerical comparisons. Aside from this, the impact of the input parameters on the free and forced vibration of the doubly-curved MEE shallow shell is examined in detail. These results may be useful in the design and manufacture of military structures such as warships, fighter aircraft, drones and missiles.

关键词： IGA approach Free and forced vibration Doubly-curved MEE shallow shell Blast load

Structurally natural chitosan films decorated with Andrographis paniculata extract and selenium nanoparticles:Properties and strawberry preservation

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Food Bioscience 2023年第3期53卷 1630-1640页

作者： Quach Thi Thanh Huong Nguyen Thanh hoai Nam Bui Thanh Duy Hoang An Nguyen Duy Hai Hoang Thuy Kim Ngan Lam Thanh Ngan Tran Le hoai Nhi Dang Thi Yen Linh Tran Nhat Khanh Dang vu Anh Thu Huu Hieu Nguyen VNU-HCM Key Laboratory of Chemical Engineering and Petroleum Processing(Key CEPP Lab)Ho Chi Minh City University of Technology(HCMUT)268 Ly Thuong Kiet StreetDistrict 10Ho Chi Minh CityViet Nam Faculty of Chemical Engineering Ho Chi Minh City University of Technology(HCMUT)268 Ly Thuong Kiet StreetDistrict 10Ho Chi Minh CityViet Nam Vietnam National University Ho Chi Minh City Linh Trung WardThu Duc CityHo Chi Minh CityViet Nam University of Science(HCMUS-VNU) 227 Nguyen Van CuDistrict 5Ho Chi Minh CityViet Nam

In this study,selenium nanoparticles(SeNPs)were synthesized using Annona glabra leaf extract as a reducing *** addition,the solution-casting method was employed to prepare the food preservation film from the chitosan-Andrographis paniculata extract-selenium nanoparticles(CS-APE-Se).The effects of SeNPs with different contents(equivalent to 1,2,3,and 4%of chitosan mass)on fundamental properties and bioactivities of the films were also *** to the results,the prepared films possess good biodegradability after 30 days of ***,the antioxidant activity of the material was also investigated via free radical scavenging toward 2-diphenyl-1-picrylhydrazyl(DPPH)and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS),which showed the inhibition rate up to 45 and 82%,***,the antibacterial performance of the films was assessed against Staphylococcus aureus and Pseudomonas aeruginosa,which indicated the highest antibacterial capacity with the inhibition diameter of 18.1±0.03 and 19.25±0.01 mm,***,the coating of the CS-APE-Se films also effectively prevented physical damage and prolonged the shelf life of the strawberries by up to 10 *** aforementioned results demonstrated the potential for applying chitosan(CS)film in combination with Andrographis paniculata leaf extract and SeNPs as a secure alternative to the harmful chemicals currently used in food preservation.

关键词： Chitosan Food packing Andrographis paniculata Selenium nanoparticles

Agrobacterium-Mediated Transformation of Cry8db Gene in Vietnam Sweet Potato Cultivar

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Journal of Life Sciences 2015年第6期9卷 262-271页

作者： Pham Bich Ngoc vu Thi Lan Tran Thu Trang Nguyen hoai Thuong Le Thu Ngoc Chu Hoang Ha Le Tran Binh Institute of Biotechnology Vietnam Academy of Science and Technology 18-Hoang Quoc Viet Cau Giay Ha Noi 10000 Vietnam College of Science Thai Nguyen University Tan Thinh Thai Nguyen 23000 Vietnam University of Science and Technology of Ha Noi 18-Hoang Quoc Viet Cau Giay Ha Noi 10000 Vietnam

Sweet potato [Ipomoea batatas （L.） Lam.] is an important food crop in the world as well as in Vietnam. It is well known as a recalcitrant crop for gene transformation and tissue culture because of its genotype dependent in vitro responses. In present study, Agrobacterium-mediated transformation of cry8Db from Bacillus thuringiensis into KB 1 sweet potato variety has been studied. The C58cv strain carrying a pBl 121 backbone which contained cry8Db delta-endotoxin gene regulated under 35 S CaMV prom oter, and the selection marker gene, neomycin phosphotransferase （npt11） gene, was subjected for plant transformation. Callus induced from shoot tips and leaf explants were inoculated and cocultured with A. tumefaciens. The selection occurred during callus producing and plant regenerating steps. A total of 201 transgenic putative plant lines were produced, and 21 transgenic lines were positively confirmed by PCR and finalized by Southern blot. Four putative transgenic lines confirming a single copy of the crySEIb gene were transferred into soil pots in greenhouse. Biological activity evaluation for the insecticidal capacity of these transgenic lines under controlled conditions showed that the level of infestation by sweet potato weevils （Cylasformicarius） in untransformed plants was higher than that of transgenic lines.

关键词： Sweet potato Agrobacterium tumefaciens plant transformation cry8Db sweet potato weevil resistance cylas formicarius.

Ecoregional variations of aboveground biomass and stand structure in evergreen broadleaved forests

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Journal of Forestry Research 2020年第5期31卷 1713-1722页

作者： Tran Van Do Mamoru Yamamoto Osamu Kozan Vo Dai Hai Phung Dinh Trung Nguyen Toan Thang Lai Thanh Hai vu Thanh Nam Trieu Thai Hung Hoang Van Thang Tran Duc Manh Cao Chi Khiem vu Tien Lam Nguyen Quang Hung Tran Hoang Quy Pham Quang Tuyen Trinh Ngoc Bon Nguyen Thi Thu Phuong Ninh Viet Khuong Nguyen Van Tuan Dang Thi Hai Ha Tran Hai Long Dang Van Thuyet Dang Thinh Trieu Nguyen Van Thinh Tran Anh Hai Duong Quang Trung Nguyen Van Bich Dinh Hai Dang Pham Tien Dung Nguyen Huy Hoang Le Thi Hanh Phan Minh Quang Nguyen Thi Thuy Huong Hoang Thanh Son Nguyen Thanh Son Nguyen Thi Van Anh Nguyen Thi hoai Anh Pham Dinh Sam Hoang Thi Nhung Hoang Van Thanh Nguyen Huu Thinh Tran Hong Van Ho Trung Luong Bui Kieu Hung Research Institute for Sustainable Humanosphere Kyoto UniversityUjiKyotoJapan Silviculture Research Institute Vietnamese Academy of Forest SciencesNorth Tu LiemHanoiVietnam Center for Southeast Asian Studies Kyoto UniversityKyotoJapan Vietnamese Academy of Forest Sciences North Tu LiemHanoiVietnam Vietnam Administration of Forestry No.2 Ngoc HaBa DinhHanoiVietnam

Biotic and abiotic factors control aboveground biomass(AGB)and the structure of forest *** study analyses the variation of AGB and stand structure of evergreen broadleaved forests among six ecoregions of Vietnam.A data set of 1731-ha plots from 52 locations in undisturbed old-growth forests was *** results indicate that basal area and AGB are closely correlated with annual precipitation,but not with annual temperature,evaporation or hours of *** area and AGB are positively correlated with trees>30 cm *** areas surveyed(52.6%)in these old-growth forests had AGB of 100–200 Mg ha^-1;5.2%had AGB of 400–500 Mg ha^-1,and 0.6%had AGB of>800 Mg ha^-*** percent of the areas surveyed had stand densities of 300–600 ***^-1,and 64%had basal areas of 20–40 m^2 ha^-*** is an important factor influencing the AGB of old-growth,evergreen broadleaved forests in *** causing the loss of large-diameter trees(e.g.,>100 cm DBH)affects AGB but may not seriously affect stand density.

关键词： Aboveground biomass Carbon storage Climatic variables Ecoregion Edaphic variables Oldgrowth forest