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  • Vietnam National University Journal of Science  (48)
  • 1
    Online Resource
    Online Resource
    One-step Synthesis of Molybdenum Oxide/graphene Composites
    Vietnam National University Journal of Science ; 2021
    In:  VNU Journal of Science: Mathematics - Physics Vol. 37, No. 1 ( 2021-03-12)
    Details
    In: VNU Journal of Science: Mathematics - Physics, Vietnam National University Journal of Science, Vol. 37, No. 1 ( 2021-03-12)
    Abstract: We herein introduce a new approach to synthesize MoO2/graphene composites via plasma-enhanced electrochemical exfoliation process. Our samples were prepared by electrifying graphite rods in (NH4)2Mo7O24 solution under a DC voltage of 70V. By controlling the experimental parameters such as the initial ratio of [Mo7O24]2– precursor, the current and time, we can modify the size and the size distribution of MoO2 nanoparticles on graphene sheets. The composites were characterized with Scanning Electron Microscopy, Transmission Electron Microscopy, X-ray Diffraction and Raman Spectroscopy.  
    Type of Medium: Online Resource
    ISSN: 2588-1124 , 2615-9341
    URL: Article
    DOI: 10.25073/2588-1124/vnumap.4521
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2021
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  • 2
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    Proposed Modeling of Online Exam-Proctoring: The Case of University of Education (VNU-UED)
    Vietnam National University Journal of Science ; 2022
    In:  VNU Journal of Science: Education Research ( 2022-12-08)
    Details
    In: VNU Journal of Science: Education Research, Vietnam National University Journal of Science, ( 2022-12-08)
    Abstract: Digital transformation in education proposed many changes in term of the formation and paradigm of teaching, assessment and evaluation in all aspects. The ability to integrate online platforms, tools, and technology solutions to increase interactivity and personalization etc. considers new opportunities and challenges for the application of online (remote) assessment and supervision platforms. As a phenomenon of online learning mode the online proctored examinations (OPE) have been considered one of the foremost online proctoring options that share the features of a real examination (paperless) in higher education institutions (HEIs) with a proctor observing examinations remotely. In teaching practice today, with online learning tendency the online proctoring (OP) interest rises for some time and accelerated by COVID-19 pandemic. Many of these online learning programs also include online assessment (online exams) that raise some of the issues and challenges associated with plagiarism and academic integrity in general. One of the ways to deal with some of these challenges is the adoption of online proctoring tools for online assessment.
    Type of Medium: Online Resource
    ISSN: 2588-1159 , 2615-9325
    URL: Article
    DOI: 10.25073/2588-1159/vnuer.4724
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2022
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  • 3
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    Synthesis of Micro/nano Urchin-like VO2 Particles and Its Decolorization of Methylene Blue
    Vietnam National University Journal of Science ; 2019
    In:  VNU Journal of Science: Mathematics - Physics Vol. 35, No. 3 ( 2019-09-13)
    Details
    In: VNU Journal of Science: Mathematics - Physics, Vietnam National University Journal of Science, Vol. 35, No. 3 ( 2019-09-13)
    Abstract: Micro/nano urchin-like VO2 particles were synthesized successfully by hydrothermal method. Vanadium pentoxide (V2O5), oxalic acid (C2H2O4) and sodium dodecyl sulfate (SDS) surfactant were used as reagents for the synthesis of VO2. In this article, we have reported the synthesis procedure of VO2 nanorods and micro/nano urchin-like VO2 structure and evaluating the methylene blue (MB) adsorption properties. Morphology and particle size of VO2 were observed by FE-SEM. The phase formation of VO2 was studied by XRD. Raman spectroscopy was also used for characterization of VO2. Micro/nano urchin-like VO2 structure was showed good MB adsorption properties that have potential applications in dye-contaminated water treatments.
    Type of Medium: Online Resource
    ISSN: 2588-1124 , 2615-9341
    URL: Article
    DOI: 10.25073/2588-1124/vnumap.4343
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2019
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  • 4
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    Application of 1H DOSY NMR in Measurement of Polystyrene Molecular Weights
    Vietnam National University Journal of Science ; 2020
    In:  VNU Journal of Science: Natural Sciences and Technology Vol. 36, No. 2 ( 2020-06-25)
    Details
    In: VNU Journal of Science: Natural Sciences and Technology, Vietnam National University Journal of Science, Vol. 36, No. 2 ( 2020-06-25)
    Abstract: In this work, we studied the applicability of diffusion ordered nuclear magnetic resonance spectroscopy (DOSY NMR) as an alternative method in determination of polystyrene molecular weight. DOSY NMR spectroscopy allows measuring the diffusion coefficient of molecule which directly depend on hydrodynamic radius and so on, average molar mass in weight (Mw). By using commercial polystyrene (PS) standards, an external calibration curve was established. Based on the excellent linear correlation between diffusion coefficient (logD) and molecular weight (logM), the molecular weight of polystyrene can be predicted using the following equation . The validation was done by comparing with the Mw value obtained by gel permeation chromatography within less than 5% deviation. From the diffusion coefficient, some property of polystyrene in solution, such as Flory coefficient and polymer-solvent interaction, were also studied. The Flory coefficient confirmed that chloroform is a good solvent for PS.
    Type of Medium: Online Resource
    ISSN: 2588-1140 , 2615-9317
    URL: Article
    DOI: 10.25073/2588-1140/vnunst.4917
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2020
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  • 5
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    Designing and Teaching Experiments in Chapter 1: Matter and Energy Metabolism - Biology 11
    Vietnam National University Journal of Science ; 2021
    In:  VNU Journal of Science: Education Research Vol. 37, No. 2 ( 2021-06-22)
    Details
    In: VNU Journal of Science: Education Research, Vietnam National University Journal of Science, Vol. 37, No. 2 ( 2021-06-22)
    Abstract: This study is carried out with the aim of designing several experiments for teaching chapter 1 - Matter and Energy Metabolism - Biology 11 as well as evaluating the effectiveness of using experiments in teaching practical competencies-oriented development. We have used various methods such as theoretical research, investigation, consultation, and pedagogical experiment to obtain objective and comprehensive results. The data are then analyzed by the highly reliable mathematical - statistical software. The results obtained in the pedagogical experiment show that using experiment in combination with other active teaching methods has initially brought about effectiveness. Experiments not only help students deepen their knowledge, but also help them build up and develop their practical competence. Therefore, the design and teaching experiments in teaching Biology is an extremely necessary for a highly effective learning.
    Type of Medium: Online Resource
    ISSN: 2588-1159 , 2615-9325
    URL: Article
    DOI: 10.25073/2588-1159/vnuer.4494
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2021
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  • 6
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    Synthesis of CeO2 -Pr2O3 Composites Applying for the Growth of Paramignya trimera
    Vietnam National University Journal of Science ; 2023
    In:  VNU Journal of Science: Natural Sciences and Technology ( 2023-09-03)
    Details
    In: VNU Journal of Science: Natural Sciences and Technology, Vietnam National University Journal of Science, ( 2023-09-03)
    Abstract: In this paper, CeO2-Pr2O3 composites were successfully fabricated using solid-phase heating and by varying the mass ratio of CeO2-Pr2O3 (CP-11, CP-12, CP-13). These synthesized materials have been characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM) and infrared spectroscopy (IR) and Energy-Dispersive X-ray spectroscopy (EDX). The obtained results showed that CeO2-Pr2O3 materials affected the growth of Paramignya compared to the control sample. The growth of Paramignya trimera achieved the best result under investigation region when the mass of CeO2/Pr2O3 is 1:2.
    Type of Medium: Online Resource
    ISSN: 2588-1140 , 2615-9317
    URL: Article
    DOI: 10.25073/2588-1140/vnunst.5550
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2023
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  • 7
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    Fish Species Composition in Hau River Basin at Hau Giang Province
    Vietnam National University Journal of Science ; 2018
    In:  VNU Journal of Science: Natural Sciences and Technology Vol. 34, No. 1 ( 2018-03-23)
    Details
    In: VNU Journal of Science: Natural Sciences and Technology, Vietnam National University Journal of Science, Vol. 34, No. 1 ( 2018-03-23)
    Abstract: This study was conducted from December 2015 to November 2016 at 44 sampling sites in the Hau River Basin at Hau Giang Province. The analysis results recorded 125 fish species belonging to 19 Orders and 46 families. The fish species composition was more diverse in wet season (119 species) than that in dry season (101 species). Of 19 orders, Cypriniformes, Siluriformes, Anabatiformes, Perciformes and Gobiformes had the highest number of species recorded during wet and dry seasons. The fish species composition had higher diversity in the ecological region regulated by east sea tide than the ecological region regulated by west sea tide and the contiguous ecological region. Keyword Rish species composition, Hau Giang, Hau river References [1] Vũ Vi An, Đoàn Văn Tiến, Lâm Phước Khiêm & Nguyễn Nguyễn Du, Đánh giá sản lượng khai thác của ngư dân vùng Đồng bằng sông Cửu Long, Tuyển tập Nghề cá sông Cửu Long, 428-436, 2011.[2] Mai Đình Yên, Nguyễn Văn Trọng, Nguyễn Văn Thiện, Lê Hoàng Yến & Hứa Bạch Loan, Định loại cá nước ngọt Nam bộ, Nxb Khoa học và Kỹ thuật, Hà Nội, 1992.[3] Trương Thủ Khoa & Trần Thị Thu Hương, Định loại cá nước ngọt vùng Đồng bằng sông Cửu Long, Tủ sách Đại học Cần Thơ, Cần Thơ, 1993.[4] Đoàn Văn Tiến & Mai Thị Trúc Chi, Quan Trắc sản lượng cá đánh bắt ở Đồng bằng sông Cửu Long, Hội thảo quốc gia về phát triển thủy sản vùng hạ lưu sông Mekong, Việt nam, Nxb Nông nghiệp, 2005.[5] Trần Đắc Định, Koichi, S., Nguyễn Thanh Phương, Hà Phước Hùng, Trần Xuân Lợi, Mai Văn Hiếu & Kenzo, U., Mô tả định loại cá Đồng bằng sông Cửu Long, Việt Nam, Nxb Đại học Cần Thơ, Cần Thơ, 2013.[6] Viện Quy hoạch thủy lợi miền Nam, Quy hoạch xây dựng thủy lợi tỉnh Hậu Giang đến năm 2020 và tầm nhìn đến năm 2030 (Tập 1 Báo cáo tổng hợp), Thành phố Hồ Chí Minh, 2012.[7] Phạm Nhật, Vũ Văn Dũng, Đỗ Quang Huy, Nguyễn Cử, Lê Nguyên Ngật, Nguyễn Hữu Dực, Nguyễn Thế Nhã, Võ Sĩ Tuấn, Phan Nguyên Hồng, Nguyễn Văn Tiến, Đào Tấn Hổ, Nguyễn Xuân Hòa, Nick Cox & Nguyễn Tiến Hiệp, Sổ tay hướng dẫn điều tra và giám sát đa dạng sinh học, Nxb Giao thông vận tải, Hà Nội, 2003.[8] Pravdin, I. F., Hướng dẫn nghiên cứu cá (Phạm Thị Minh Giang dịch), Nxb Khoa học và Kỹ thuật, Hà Nội, 1973.[9] Nguyễn Văn Hảo & Ngô Sỹ Vân, Cá nước ngọt Việt Nam, Nxb Nông Nghiệp, Hà Nội, 2001.[10] Nguyễn Văn Hảo, Cá nước ngọt Việt Nam, Nxb Nông nghiệp, Hà Nội, 2005.[11] Nguyễn Văn Hảo, Cá nước ngọt Việt Nam, Nxb Nông nghiệp, Hà Nội, 2005.[12] Rainboth, W. J., Fishes of the Cambodian Mekong, FAO, Roma, 1996.[13] Froese, R. & Pauly, D., FishBase, World Wide Web electronic publication, 2017, truy cập ngày 10/06/2017. www.fishbase.org[14] Nguyễn Ngọc Anh, 2016. Hạn - mặn lịch sử 2016 ở Đồng bằng sông Cửu Long: bài học kinh nghiệm và những giải pháp ứng phó, Tạp chí Khoa học và Công nghệ Việt Nam, Hà Nội, 19/01/2018, http://www.khoahocvacongnghevietnam.com.vn/khcn-trung-uong/13123-han-man-lich-su-2016-0-dong-bang-song-cuu-long-bai-hoc-kinh-nghiem-va-giai-phap-ung-pho.  
    Type of Medium: Online Resource
    ISSN: 2588-1140 , 2588-1140
    URL: Article
    DOI: 10.25073/2588-1140/vnunst.4723
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2018
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  • 8
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    Enhancing Poly(3,4-ethylenedioxythiophene) Polystyrene Sulfonate (PEDOT:PSS) Conductivity by Dimethyl Sulfoxide (DMSO) Dopant
    Vietnam National University Journal of Science ; 2023
    In:  VNU Journal of Science: Mathematics - Physics Vol. 39, No. 1 ( 2023-03-27)
    Details
    In: VNU Journal of Science: Mathematics - Physics, Vietnam National University Journal of Science, Vol. 39, No. 1 ( 2023-03-27)
    Abstract: Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), a type of conducting polymer has caught lots of attraction from scientists for its excellent properties as low-cost, non-toxic, etc. This also is a potential material for various applications as transparent electrodes, flexible and stretchable devices, thus improving the electrical properties of this polymer plays an important role. Among various methods such as post-treatment, doping with glycerol, and d-sorbitol herein, DMSO was chosen as an additive to enhance the conductivity of PEDOT:PSS. The results, including the increase in the films conductance according to the rise of DMSO dopant ratio from 0 to 2, good transmittance and surface morphology were clearly presented. This will be the platform for the further study of the utilization of PEDOT:PSS in various potential optoelectronic devices in the future.  
    Type of Medium: Online Resource
    ISSN: 2588-1124 , 2615-9341
    URL: Article
    DOI: 10.25073/2588-1124/vnumap.4785
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2023
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  • 9
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    Góp phần nghiên cứu tổng hợp một số N-(ω-azidoalkyl)isatin thế từ các isatin thế và không thế
    Vietnam National University Journal of Science ; 2022
    In:  VNU Journal of Science: Natural Sciences and Technology Vol. 38, No. 1 ( 2022-03-15)
    Details
    In: VNU Journal of Science: Natural Sciences and Technology, Vietnam National University Journal of Science, Vol. 38, No. 1 ( 2022-03-15)
    Abstract: Tóm tắt: Các dẫn xuất azide của isatin là các chất đầu cần thiết cho phản ứng click để tạo ra dị vòng 1,2,3-triazole. Các dẫn xuất N-(ω-bromoalkyl)isatin cần cho chuyển hoá được tổng hợp từ phản ứng thế nucleophile của các isatin tương ứng với các dibromoalkane thích hợp. Một số N-(ω-azidoalkyl)isatin có chứa nhóm thế hoặc không thế ở vòng benzene đã được tổng hợp bằng phản ứng của các N-(ω-bromoalkyl)isatin tương ứng đã tổng hợp được với natri azide. Phản ứng được thực hiện trong DMF khan với sự có mặt của KI với vai trò chất xúc tiến. Hiệu suất sản phẩm đạt được 30−85%. Abstract: Azide derivatives of isatins were the needed initial materials for click chemistry in order to form 1,2,3-triazoles. N-(ω-Bromoalkyl)isatins were prepared by nucleophilic reaction of (un)substituted isatins with appropriate dibromoalkanes. Some ω-azidoalkylisatins were synthesized by reaction of corresponding ω-bromoalkylisatins with sodium azide. The reactions were performed in dry DMF as solvent in the presence of KI as promotive agent. Product yields achived 30−85%.
    Type of Medium: Online Resource
    ISSN: 2588-1140 , 2615-9317
    URL: Article
    DOI: 10.25073/2588-1140/vnunst.5174
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2022
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  • 10
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    Uvaria clementis (Merr.) Attan., I. M. Turner and R. M. K. Saunders (Annonaceae), a New Record for the Flora of Vietnam
    Vietnam National University Journal of Science ; 2022
    In:  VNU Journal of Science: Natural Sciences and Technology ( 2022-10-15)
    Details
    In: VNU Journal of Science: Natural Sciences and Technology, Vietnam National University Journal of Science, ( 2022-10-15)
    Abstract: The genus Uvaria Juss. is distinguished other genus of Annonaceae especially: Stellate or caespitose hairs, flowers bisexual opposite to leaves, flower are solitary or cymose. Sepal 3, valvate,… Uvaria clementis (Merr.) Attan., I.M. Turn & R.M.K Saunders distributed from  Malaysia, Indonesia, Brunei to Thailan, Campuchia,… The specimen which collected at Dongnai province and saved at The Hebarium National Instiute of Medicinal Materialis is newly recorded for the flora of Vietnam. This study, we are described, illustrated and notes on taxonomy of Uvaria clementis Teaching and scientific research are two main.
    Type of Medium: Online Resource
    ISSN: 2588-1140 , 2615-9317
    URL: Article
    DOI: 10.25073/2588-1140/vnunst.5261
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2022
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