Dalat University Journal of Science / Tạp chí khoa học Đại học Đà Lạt
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HYDROGEN DEFECTS ON THE SURFACE OF LEAD-FREE FERROELECTRIC NaBiTiO MATERIALS
Get PDFHydrogen atomic chemisorption and adsorption at all possible vacancy sites on the surface of perovskite Na0.5Bi0.5TiO3 (110) were explored using calculations from density functional theory. Our calculations reveal that a pristine Na0.5Bi0.5TiO3 (110) surface can exhibit direct and indirect transitions characterized by optical bandgaps of 2.68 eV and 2.75 eV, respectively. The density of states of the Na0.5Bi0.5TiO3 (110) surface indicates predominant electron transitions from O-2p valence bands to Ti-3d and Bi-6p conduction bands in the low-energy range. Hydrogen substitution at vacancies can induce magnetism, whereas hydrogen adsorption enhances both the magnetism and conductivity of the surface system. In particular, the charge density reveals electron transfer between cations and hydrogen atoms, providing insight into the variations in hydrogen bonding properties in these surface systems. These observations expand our understanding of hydrogen chemisorption and adsorption on defect sites, providing a novel avenue for investigating and potentially developing environmentally friendly multiferroic materials for advanced electronic devices
RECONSTRUCTION OF DIVACANCY IN ZIGZAG-BUCKLED SILICENE NANORIBBONS
Get PDFIn this study, we use a tight binding model to investigate structural and electronic changes in zigzag-buckled silicene nanoribbons (ZBSiNRs) with two vacancies at different positions. We divide the defects into two categories based on a difference in geometric properties. The results show that the first- and second-order interaction parameters of two atoms of the same type play an important role in the electronic properties of this material. Vacancies near the edge have a stronger effect than those near the center of the ribbons. We further show that each type of divacancy will give a different result under the influence of a perpendicular electric field. This is a favorable condition for controlling the conductive state of materials in future applications in the semiconductor and thermoelectric industries
A REVISIT OF VIETNAM-INDIA CULTURAL DIPLOMACY ACTIVITIES (2016–2021) AND ITS PROSPECTS
Get PDFThis article traces the evolution of Vietnam-India cultural relations between 2016 and 2021. The methodology of qualitative research design, data collection, and thematic and textual analysis are used to shed light on the rise of Vietnam’s and India’s cultural diplomacy. The article describes the substantial development in Vietnam-India cultural diplomacy between 2016 and 2021 with clear evidence of cultural events. Based on the closely examined process of India-Vietnam cultural relations and the national policies of Vietnam and India, the author provides an outlook for these bilateral cultural ties in the future
BEHAVIOR OF THE NGUYEN DYNASTY FOR TEACHERS IN SOUTHERN VIETNAM
Get PDFThis article examines the educational policies and cultural behavior of the Nguyen Dynasty toward teachers in the South to answer the following questions: What were the policies for establishing schools in the South? What was the purpose of the Nguyen Dynasty in regulating teachers and students? What were the differences in behavior of the Nguyen Dynasty toward Southern teachers compared with other localities? What were the similarities and differences between public and private schools in the South? To answer these questions, we collect and document bibliographic sources. Using methods of comparison, analysis, and synthesis, we outline the process of implementing educational policies in general, policies to manage teachers in the South in particular, and assess the role of teachers and teacher standards in improving the quality of education during the Nguyen Dynasty. In addition, this article also compares the differences in the behavior of the Nguyen Dynasty toward teachers in public and private schools in different localities and provides comments and assessments on the cultural behavior of the Nguyen Dynasty toward teachers in the feudal South
CAMELLIA HOABINHENSIS (THEACEAE: SECT. CHRYSANTHA), A NEW YELLOW-FLOWERED SPECIES FROM NORTHERN VIETNAM
Get PDFA new species, Camellia hoabinhensis (section Chrysantha, Theaceae), is described and illustrated based on specimens collected from a lowland forest on limestone hills in Hoa Binh Province, northern Vietnam. The species is characterized by its small habit to 4.5 m tall, large flowers 9.0–9.5 cm in diameter with 18–19 light yellow petals, and hairy filaments, ovaries, and styles. A comparison of the new species with similar species, C. euphlebia, C. impressinervis, C. phanii, and C. velutina, is provided. The IUCN conservation status of the proposed species is Data Deficient (DD)
A LOOK BACK ON THE VERSE OF PHAN VĂN TRỊ AFTER 130 YEARS
Get PDFPhan Văn Trị (潘文值1830–?) was a prominent writer in Cochinchina in the late nineteenth century. He achieved the rank of senior bachelor (舉人 cử nhân) in the Confucian court examination at a young age but never joined the imperial bureaucracy. Despite living an agrarian life as a layman, he was popular all over Cochinchina for his talent in poetry creation. When the three provinces of Eastern Cochinchina were taken by the French, Phan Văn Trị led a patriotic writing movement against Tôn Thọ Tường (尊壽祥) and his idea of surrendering to the colonizers. Phan Văn Trị was famous for his polemical poems, object poems, and pastoral poems. This article provides a brief literature review of Phan Văn Trị’s writings, describes the condition of his texts, and evaluates his poetry
SECONDARY TEACHERS’ AND STUDENTS’ PERCEPTIONS OF DISTANCE EDUCATION IN SCIENCE: FOCUS ON LEARNER-CENTERED, ACTION-ORIENTED, AND TRANSFORMATIVE LEARNING
Get PDFThe shift from conventional, face-to-face classroom teaching to distance education is a complex process that brings various challenges. To better understand the impact of this transition, the researchers examined the perceptions of secondary science teachers (n = 42) and students (n = 137). Specifically, the study focused on evaluating learner-centered, action-oriented, and transformative learning – referred to as LCAOT learning – in science distance education. The researchers developed a 26-item, 4-point Likert scale questionnaire that was distributed online to the target respondents. Additionally, the researchers interviewed teachers and students and analyzed various documents, such as self-learning modules and learners’ activity sheets, to triangulate the survey data. The findings revealed that the principles of LCAOT learning were apparent in science distance education and exemplified through tools such as the Know, Want to Know, and Learned charts and personal journals. The study also revealed that teachers and students faced challenges during the transition to distance education, including inadequate equipment and poor internet connectivity. However, they responded to these challenges by using various means of communication, collaborating with peers, and exploring new roles and identities. The researchers recommend using the developed instrument and continuing to evaluate the effectiveness of teaching strategies employed in distance education in science, as well as further studies on the impact of LCAOT learning on students’ academic achievement
TRENDS IN THE SCIENTIFIC LITERATURE ON THE LEAGILE SUPPLY CHAIN: BIBLIOMETRIC AND CITATION CONTEXT ANALYSES
Get PDFLeagile is a hybrid of conventional lean and agile approaches intended to eliminate specific constraints and capacity limitations and enable agility in highly competitive business environments. Interest in incorporating lean and agile into the supply chain has grown in recent years, as shown by the growing number of scientific publications on this topic. This topic has garnered significant interest across a wide range of academic disciplines; however, a comprehensive study of the literature in this field has not yet been conducted. Therefore, the present study aims to provide a state-of-the-art summary of leagile supply chain issues that concern researchers. To do so, we use a bibliometric method, combined with citation context analysis, to evaluate data extracted from Scopus peer-reviewed articles published between 1999 and March 2023. Data analytic techniques, including citation analysis, co-citation analysis, and co-word (co-occurrence) analysis, are used. Using rigorous bibliometric and visualization tools, the results show the current status of the research problem, its impact, and suggestions for future work to address research gaps, such as a problem in an area of research that has been answered incompletely or insufficiently. The findings suggest that researchers in unexplored research areas in the ASEAN region include green supply chain strategies, supply chain risk management influenced by lean and agile strategies, and comparative analyses among ASEAN countries. These areas offer promising avenues for future research, contributing to regional competitiveness and performance enhancement
RETRACTED: THE ISSUE OF FEMININITY IN THE SHORT STORY COLLECTION OF THE WIND FLOWS THROUGH BY LE MINH KHUE
No full textRetraction Notice
Retraction: Kieu, T. U. (2023). The issue of femininity in the short story collection of The Wind Flows Through by Le Minh Khue. Dalat University Journal of Science, 13(4), 32-47. https://doi.org/10.37569/DalatUniversity.13.4.1053(2023)
This article has been retracted at the request of the Editor-in-Chief due to duplicate publication. In September 2023, the Dalat University Journal of Science (DLU-JOS) became aware that the article had previously been published elsewhere by the same author. This matter may have arisen from the practice of submitting identical studies nearly simultaneously, either in the same or another language, to two journals. We have reason to believe that this issue was due to the author’s inadvertent error rather than research misconduct.
In accordance with the international guidelines established by the Committee on Publication Ethics, of which the DLU-JOS is a member, we have determined that these are grounds for retraction.
The author has agreed to the retraction of the paper.
The DLU-JOS regrets this incident and extends its apologies to its readers
ASSESSMENT OF THE HEALTH AND ECOLOGICAL RISKS CAUSED BY FUNGICIDES IN CHRYSANTHEMUM CULTIVATION BY ENVIRONMENTAL IMPACT QUOTIENT
Get PDFThis study uses the Environmental Impact Quotient (EIQ) to assess the health and ecological risks caused by fungicides used in chrysanthemum cultivation upstream of Xuan Huong Lake, Da Lat city. Survey results reveal that 134 farmers use 21 fungicides with 18 active ingredients on a total area of 35.2 hectares. In all, 18 fungicides with an EIQ at the level of “unlikely to be hazardous” (EIQ < 25) are used on about 95% of the acreage, and 3 fungicides with an EIQ of “slightly hazardous” (25 < EIQ < 50) are used on the rest of the area. The Field Use EIQ of fungicide was rated very low in only 8.2% of the survey area and moderate in 48%. Areas with high and very high ratings account for 3% and 41%, respectively. Using fungicides according to the instructions can reduce the Field Use EIQ values in cultivated areas by 38% and return areas with high and moderate ratings to a low rating. Therefore, it is necessary to instruct farmers on the safe use of fungicides and to recommend those with low EIQ values for chrysanthemum cultivation