HNUE Journal of Science Hanoi National University of Education
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BUILDING A RUBRIC FOR ASSESSING MATHEMATICAL COMMUNICATION COMPETENCE IN GRADE 5 STUDENTS
Get PDFMathematical communication competence is a core component of mathematical competence, helping students to receive, construct, and express mathematical thinking effectively and accurately. However, in reality, primary school teachers still have difficulty in assessing students\u27 mathematical communication competence, including 5th graders, leading to an ineffective impact on the teaching process to develop students\u27 mathematical communication competence. Based on the understanding of theories of mathematical communication competence and the requirements presented in the 2018 National Mathematics Education Curriculum, this article presents a rubric for assessing mathematical communication competence in grade 5 students. This assessment tool is designed to help teachers accurately assess the mathematical communication competence of grade 5 students.Mathematical communication competence is a core component of mathematical competence, helping students to receive, construct, and express mathematical thinking effectively and accurately. However, in reality, primary school teachers still have difficulty in assessing students\u27 mathematical communication competence, including 5th graders, leading to an ineffective impact on the teaching process to develop students\u27 mathematical communication competence. Based on the understanding of theories of mathematical communication competence and the requirements presented in the 2018 National Mathematics Education Curriculum, this article presents a rubric for assessing mathematical communication competence in grade 5 students. This assessment tool is designed to help teachers accurately assess the mathematical communication competence of grade 5 students
SYNTHESIS AND OPTICAL PROPERTIES OF NITROGEN-DOPED CARBON QUANTUM DOTS
Get PDFNitrogen-doped carbon quantum dots (N-CQDs) were successfully synthesized using a hydrothermal method at 150°C for 3 hours, with glucose and urea serving as the carbon and nitrogen precursors, respectively. The resulting N-CQDs, which had an average particle size of 3.60 ± 0.57 nm, exhibited blue fluorescence with an emission peak approximated 485.5 nm when excited at 370 nm. The photoluminescence intensity of the N-CQDs was pH-dependent, reaching its maximum at pH 5.0. Fourier transform infrared spectroscopy analysis revealed that the surface of the N-CQDs contained functional groups with carbon, nitrogen, and oxygen bonds, which contributed to their excellent water solubility and strong blue photoluminescence (quantum yield of 23%). These properties indicate that N-CQDs have high potential for applications in bioimaging and biosensing.Nitrogen-doped carbon quantum dots (N-CQDs) were successfully synthesized using a hydrothermal method at 150°C for 3 hours, with glucose and urea serving as the carbon and nitrogen precursors, respectively. The resulting N-CQDs, which had an average particle size of 3.60 ± 0.57 nm, exhibited blue fluorescence with an emission peak approximated 485.5 nm when excited at 370 nm. The photoluminescence intensity of the N-CQDs was pH-dependent, reaching its maximum at pH 5.0. Fourier transform infrared spectroscopy analysis revealed that the surface of the N-CQDs contained functional groups with carbon, nitrogen, and oxygen bonds, which contributed to their excellent water solubility and strong blue photoluminescence (quantum yield of 23%). These properties indicate that N-CQDs have high potential for applications in bioimaging and biosensing
EXISTENCE AND LONG-TIME BEHAVIOR OF SOLUTIONS TO A CLASS OF DOUBLY NONLINEAR PARABOLIC EQUATIONS INVOLVING WEIGHTED p-LAPLACIAN OPERATORS
Get PDFIn this paper, we study the existence, uniqueness, and long-time behavior of global weak solutions to a class of doubly nonlinear degenerate parabolic equations involving weighted p-Laplacian operators in bounded domains with homogeneous Dirichlet boundary conditions. The global existence and uniqueness of weak solutions are established by combining compactness arguments with the theory of monotone operators. Furthermore, we analyze the asymptotic dynamics of the system and prove the existence of a compact global attractor by employing the theory of global attractors in bi-spaces.In this paper, we study the existence, uniqueness, and long-time behavior of global weak solutions to a class of doubly nonlinear degenerate parabolic equations involving weighted p-Laplacian operators in bounded domains with homogeneous Dirichlet boundary conditions. The global existence and uniqueness of weak solutions are established by combining compactness arguments with the theory of monotone operators. Furthermore, we analyze the asymptotic dynamics of the system and prove the existence of a compact global attractor by employing the theory of global attractors in bi-spaces
RESEARCH ON THE TECHNOLOGICAL PARAMETERS OF ORANGE RAKIA PRODUCTION
Get PDFThis research aims to identify the technological parameters involved in the production of rakia from Ha Giang oranges. The fermentation must was prepared by adding the disinfectant and antioxidant K2S2O5 at a concentration of 150 mg/L to ensure the sterility and stability of the orange juice for the subsequent fermentation stage. Using the native yeast strain Saccharomyces cerevisiae HB2 isolated from oranges, the factors influencing the fermentation process were determined, including fermentation temperature of 30oC, initial total soluble solids after adding sugar of 20°Bx, initial yeast cell density of 8.5 x 106 CFU/mL, and pH of 4.1. At the pilot scale of 5 liters, after fractional distillation and the removal of 3% ethanol from the head and 3% from the tail fractions, the resulting heart fraction had an alcohol concentration of 53% vol. After dilution to a final alcohol concentration of 35% vol by distilled water, the finished rakia had a characteristic orange aroma. The sensory score achieved was 18.16, which is in the ‘good’ category.This research aims to identify the technological parameters involved in the production of rakia from Ha Giang oranges. The fermentation must was prepared by adding the disinfectant and antioxidant K2S2O5 at a concentration of 150 mg/L to ensure the sterility and stability of the orange juice for the subsequent fermentation stage. Using the native yeast strain Saccharomyces cerevisiae HB2 isolated from oranges, the factors influencing the fermentation process were determined, including fermentation temperature of 30oC, initial total soluble solids after adding sugar of 20°Bx, initial yeast cell density of 8.5 x 106 CFU/mL, and pH of 4.1. At the pilot scale of 5 liters, after fractional distillation and the removal of 3% ethanol from the head and 3% from the tail fractions, the resulting heart fraction had an alcohol concentration of 53% vol. After dilution to a final alcohol concentration of 35% vol by distilled water, the finished rakia had a characteristic orange aroma. The sensory score achieved was 18.16, which is in the ‘good’ category
SYNTHESIS, STRUCTURAL STUDIES AND ACETYLCHOLINESTERASE INHIBITION ACTIVITY OF SOME (E)-2-METHOXY-3-NITRO-4-(3-OXO-3-ARYLPROP-1-EN-1-YL)PHENYL ACETATES
Get PDFA semi-synthetic process from vanillin (isolated from vanilla) was developed to obtain new esters with potential inhibitory activity against the acetylcholinesterase (AchE.). 2-Nitrovanillin was synthesized from vanillin byesterification, nitration, and hydrolysis reactions. Four chalcones were synthesizedby acid-catalyzed condensation reaction of 2-nitrovanillin and methyl aryl ketone. The identity of 2-nitrovanillin and four chalcones was confirmed by thin-layer chromatography compared with the known compounds. Subsequent esterification of the chalcones with acetic anhydride yielded four new derivatives of (E)-2-methoxy-3-nitro-4-(3-oxo-3-(aryl)prop-1-en-1-yl)phenyl acetate. The structures ofthe four new compounds were elucidated by 1H NMR and 13C NMR spectra. Thefour compounds were evaluated for their inhibitory activity against AChE. and three of them exhibited significant activity.A semi-synthetic process from vanillin (isolated from vanilla) was developed to obtain new esters with potential inhibitory activity against the acetylcholinesterase (AchE.). 2-Nitrovanillin was synthesized from vanillin byesterification, nitration, and hydrolysis reactions. Four chalcones were synthesizedby acid-catalyzed condensation reaction of 2-nitrovanillin and methyl aryl ketone. The identity of 2-nitrovanillin and four chalcones was confirmed by thin-layer chromatography compared with the known compounds. Subsequent esterification of the chalcones with acetic anhydride yielded four new derivatives of (E)-2-methoxy-3-nitro-4-(3-oxo-3-(aryl)prop-1-en-1-yl)phenyl acetate. The structures ofthe four new compounds were elucidated by 1H NMR and 13C NMR spectra. Thefour compounds were evaluated for their inhibitory activity against AChE. and three of them exhibited significant activity
ULTIMATE BOUNDS OF RAPIDLY TIME-VARYING SYSTEMS: AN AVERAGING APPROACH
Get PDFThis paper addresses the problem of state bounding for rapidly time-varying linear systems with bounded disturbances. Based on an averaging method and Lyapunov scheme, we derive an explicit bound on the time-scale parameter for which an explicit form of asymptotic bound of solutions is obtained. An application in fast switching systems is presented to illustrate the effectiveness of the analysis results.This paper addresses the problem of state bounding for rapidly time-varying linear systems with bounded disturbances. Based on an averaging method and Lyapunov scheme, we derive an explicit bound on the time-scale parameter for which an explicit form of asymptotic bound of solutions is obtained. An application in fast switching systems is presented to illustrate the effectiveness of the analysis results
THE THERMODYNAMIC CONTACT ANGLE IN THE PREWETTING PHASE OF A BINARY BOSE-EINSTEIN CONDENSATE MIXTURE
Get PDFTo investigate the prewetting state of a Bose-Einstein condensate (BEC) mixture adsorbed on an optical hard wall at zero temperature, we consider a system in which condensate 1 coexists with condensate 2 with the chemical potential held fixed. Using the double parabola approximation (DPA) and solving the coupled Gross-Pitaevskii equations, we derive an analytical expression for the thermodynamic contact angle based on Youngs equation. Although the resulting formula is not algebraically simple, it reveals that complete wetting can occur before the bulk coexistence point is reached, indicating the presence of a continuous (second-order) prewetting transition. Our findings are in agreement with theoretical predictions in the literature and emphasize that the wetting film thickness grows smoothly without a discontinuous jump. This work provides useful guidance for the design of experiments aimed at observing wetting phenomena in Bose-Einstein condensates.To investigate the prewetting state of a Bose-Einstein condensate (BEC) mixture adsorbed on an optical hard wall at zero temperature, we consider a system in which condensate 1 coexists with condensate 2 with the chemical potential held fixed. Using the double parabola approximation (DPA) and solving the coupled Gross-Pitaevskii equations, we derive an analytical expression for the thermodynamic contact angle based on Youngs equation. Although the resulting formula is not algebraically simple, it reveals that complete wetting can occur before the bulk coexistence point is reached, indicating the presence of a continuous (second-order) prewetting transition. Our findings are in agreement with theoretical predictions in the literature and emphasize that the wetting film thickness grows smoothly without a discontinuous jump. This work provides useful guidance for the design of experiments aimed at observing wetting phenomena in Bose-Einstein condensates
PRELIMINARY STUDY OF SPECIES COMPOSITION AND DISTRIBUTION OF BEETLES (INSECTA: COLEOPTERA) IN DU GIA COMMUNE, DU GIA NATIONAL PARK - DONG VAN KARST PLATEAU, TUYEN QUANG PROVINCE
Get PDFThis study investigated the species composition and distribution of beetles across three habitats in Du Gia commune, located within Du Gia National Park - Dong Van Karst Plateau, Tuyen Quang Province. The study employed a direct survey of beetles across three habitats, conducted over three sampling periods. A total of 39 beetle species, belonging to 10 families and 33 genera, were recorded. The family Coccinellidae contained the highest number of taxa, with 13 species (33.33%) and 10 genera (30.30%). Three families, Phalacridae, Ptinidae, and Scarabaeidae, had the lowest number, each with one species (2.56%) and one genus (3.03%). The distribution of beetle species varied among habitats. The natural forest habitat supported the highest diversity, with 38 species (97.45%) recorded; followed by the grassland and shrub habitat on the mountainside with 34 species (87.18%); and the agricultural land and fruit tree habitat with 24 species (61.52%). The composition of beetle species also varied across survey phases. Phase 1 (October 2024) yielded the highest species richness, with 39 species recorded (100%); Phase 2 (January 2025) with 21 species (53.85%); and Phase 3 (March 2025) with 35 species (89.74%).This study investigated the species composition and distribution of beetles across three habitats in Du Gia commune, located within Du Gia National Park - Dong Van Karst Plateau, Tuyen Quang Province. The study employed a direct survey of beetles across three habitats, conducted over three sampling periods. A total of 39 beetle species, belonging to 10 families and 33 genera, were recorded. The family Coccinellidae contained the highest number of taxa, with 13 species (33.33%) and 10 genera (30.30%). Three families, Phalacridae, Ptinidae, and Scarabaeidae, had the lowest number, each with one species (2.56%) and one genus (3.03%). The distribution of beetle species varied among habitats. The natural forest habitat supported the highest diversity, with 38 species (97.45%) recorded; followed by the grassland and shrub habitat on the mountainside with 34 species (87.18%); and the agricultural land and fruit tree habitat with 24 species (61.52%). The composition of beetle species also varied across survey phases. Phase 1 (October 2024) yielded the highest species richness, with 39 species recorded (100%); Phase 2 (January 2025) with 21 species (53.85%); and Phase 3 (March 2025) with 35 species (89.74%)
PUBLIC SPEAKING ANXIETY AND STRATEGIES TO OVERCOME THROUGH PUBLIC SPEAKING SKILL TRAINING
Get PDFPublic speaking is recognized as one of the most essential skills in the 21st century, playing a crucial role in assessing students’ speaking abilities and overall communication competence. This is especially important for EFL university students, who face significant challenges in mastering public speaking. This study aims to investigate the causes of public speaking anxiety and examine the effects of workshops on improving students\u27 public speaking skills. Data were collected through questionnaires with 135 university students in Can Tho city. The findings indicate that the strategies introduced in workshops have a positive impact on students’ public speaking abilities, with fear of negative evaluation identified as the primary source of anxiety. The study also provides pedagogical implications for lecturers and school administrators.Public speaking is recognized as one of the most essential skills in the 21st century, playing a crucial role in assessing students’ speaking abilities and overall communication competence. This is especially important for EFL university students, who face significant challenges in mastering public speaking. This study aims to investigate the causes of public speaking anxiety and examine the effects of workshops on improving students\u27 public speaking skills. Data were collected through questionnaires with 135 university students in Can Tho city. The findings indicate that the strategies introduced in workshops have a positive impact on students’ public speaking abilities, with fear of negative evaluation identified as the primary source of anxiety. The study also provides pedagogical implications for lecturers and school administrators
RESEARCH ON THE STATUS OF LABOR IMMIGRATION IN BAC NINH PROVINCE
Get PDFVận dụng các phương pháp nghiên cứu truyền thống trong địa lí kết hợp với phương pháp điều tra xã hội học, nhóm tác giả đã khảo sát thực trạng nhập cư lao động trên địa bàn tỉnh Bắc Ninh. Kết quả cho thấy số lượng lao động di cư đến Bắc Ninh trong những năm gần đây đã tăng lên nhanh chóng, đưa địa phương này trở thành một trong những tỉnh có tỉ suất nhập cư cao nhất cả nước. Lao động nhập cư vào Bắc Ninh hầu hết trong độ tuổi khá trẻ, tham gia vào nhiều ngành nghề khác nhau nhưng đa số làm việc trong các khu công nghiệp và hầu hết có mức thu nhập cao hơn so với trước đây. Tuy nhiên, lực lượng lao động nhập cư đông đảo ở đây vẫn có tỉ lệ chưa qua đào tạo khá cao, và còn gặp nhiều khó khăn về điều kiện sinh sống, làm việc.Using traditional research methods in geography combined with sociological investigation, the authors surveyed the current situation of labor immigration in Bac Ninh province. The results show that the number of migrant workers to Bac Ninh in recent years has increased rapidly, making this locality one of the provinces with the highest immigration rate in the country. Migrant workers to Bac Ninh are mostly young, participating in many different occupations, mostly in industrial zones, and have higher incomes than before. However, the large immigrant labor force here still has a high rate of untrained labor and still faces many difficulties in living and working conditions