The article put focuses on clarifying the changes in urban space in Cu Chi district (Ho Chi Minh City) from 1997, when the first industrial park was established, to 2015. This process has changed the economic, social and cultural life of Cu Chi. From then on, the article aims to make a practical contribution to the assessment of the impact of urbanisation on the development of Cu Chi district.
{"title":"The change of urban space in Cu Chi district, Ho Chi Minh City in the urbanization process from 1997 to 2015","authors":"Tran Thanh Minh","doi":"10.56824/vujs.2021sh34","DOIUrl":"https://doi.org/10.56824/vujs.2021sh34","url":null,"abstract":"The article put focuses on clarifying the changes in urban space in Cu Chi district (Ho Chi Minh City) from 1997, when the first industrial park was established, to 2015. This process has changed the economic, social and cultural life of Cu Chi. From then on, the article aims to make a practical contribution to the assessment of the impact of urbanisation on the development of Cu Chi district.","PeriodicalId":447825,"journal":{"name":"Vinh University Journal of Science","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127334750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tran Trung Hieu, Dau Xuan Duc, Nguyen Hai Nam, Phan Thi Thuy, Tran Dinh Thang
From an ethyl acetate extract of the barks of Chukrasia tabularis, three compounds including one limonoid (tabularisin A), one flavonoid (quercetin), and one coumarin (scopoletin) were isolated by chromatographic methods. Their structures were comfirmed by analysis of spectroscopic data (ESI-MS, 1H-NMR, 13C-NMR, DEPT, HMBC, HSQC và COSY) and by comparison with the literature reports.
从板栗树皮的乙酸乙酯萃取物中分离得到1个类柠檬素(板栗素A)、1个类黄酮(槲皮素)和1个香豆素(东莨菪素)。通过光谱数据(ESI-MS, 1H-NMR, 13C-NMR, DEPT, HMBC, HSQC v COSY)分析和与文献报道的比较证实了它们的结构。
{"title":"Isolation and structure determination of compounds from ethyl acetate extract of Chukrasia tabularis","authors":"Tran Trung Hieu, Dau Xuan Duc, Nguyen Hai Nam, Phan Thi Thuy, Tran Dinh Thang","doi":"10.56824/vujs.2022nt20","DOIUrl":"https://doi.org/10.56824/vujs.2022nt20","url":null,"abstract":"From an ethyl acetate extract of the barks of Chukrasia tabularis, three compounds including one limonoid (tabularisin A), one flavonoid (quercetin), and one coumarin (scopoletin) were isolated by chromatographic methods. Their structures were comfirmed by analysis of spectroscopic data (ESI-MS, 1H-NMR, 13C-NMR, DEPT, HMBC, HSQC và COSY) and by comparison with the literature reports.","PeriodicalId":447825,"journal":{"name":"Vinh University Journal of Science","volume":"2016 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127422029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dang Van Trong, Le Tran Bao Tran, HO Thi Anh Thu, Nguyễn Thi Thuy, Chu Van Lanh
The dispersion characteristics of As2S3 solid-core photonic crystal fibers were investigated with the change of structural parameters including filling factor ( ) and lattice constant ( ). Photonic crystal fiber obtained diverse dispersion including all-normal and anomalous dispersion with two zero-wavelengths dispersion at all values of lattice constant investigated. The dispersion value increases when the lattice constant increases and the filling factor decreases. Photonic crystal fiber has a flat dispersion curve and closeness to the zero-dispersion curve in the long-wavelength range are advantages of this design. Based on the analysis of numerical simulation results, we have proposed two structures with optimal dispersion for the application of supercontinuum generation.
{"title":"Study on dispersion characteristics of square solid-core photonic crystal fibers with As2S3 substrate","authors":"Dang Van Trong, Le Tran Bao Tran, HO Thi Anh Thu, Nguyễn Thi Thuy, Chu Van Lanh","doi":"10.56824/vujs.2022nt5","DOIUrl":"https://doi.org/10.56824/vujs.2022nt5","url":null,"abstract":"The dispersion characteristics of As2S3 solid-core photonic crystal fibers were investigated with the change of structural parameters including filling factor ( ) and lattice constant ( ). Photonic crystal fiber obtained diverse dispersion including all-normal and anomalous dispersion with two zero-wavelengths dispersion at all values of lattice constant investigated. The dispersion value increases when the lattice constant increases and the filling factor decreases. Photonic crystal fiber has a flat dispersion curve and closeness to the zero-dispersion curve in the long-wavelength range are advantages of this design. Based on the analysis of numerical simulation results, we have proposed two structures with optimal dispersion for the application of supercontinuum generation.","PeriodicalId":447825,"journal":{"name":"Vinh University Journal of Science","volume":"167 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115416455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper proposes an approximate search algorithm to solve the student-internship allocation problem. The key idea of the algorithm is that in each iteration, each student unassigned to an enterprise will be assigned to an enterprise where the student ranks it highest, and it remains at maximum capacity. If the enterprise assigned to the student overcomes its capacity, then the enterprise will remove a student to whom it ranks the worst student to allow it not to overcome its capacity. Experimental results with randomly generated datasets show that our algorithm is efficient for the problem of large sizes.
{"title":"An approximate search algorithm for the student-internship allocation problem","authors":"Nguyen Quang Ninh, Dinh Van Nam, Hoang Huu Viet","doi":"10.56824/vujs.2022nt22","DOIUrl":"https://doi.org/10.56824/vujs.2022nt22","url":null,"abstract":"This paper proposes an approximate search algorithm to solve the student-internship allocation problem. The key idea of the algorithm is that in each iteration, each student unassigned to an enterprise will be assigned to an enterprise where the student ranks it highest, and it remains at maximum capacity. If the enterprise assigned to the student overcomes its capacity, then the enterprise will remove a student to whom it ranks the worst student to allow it not to overcome its capacity. Experimental results with randomly generated datasets show that our algorithm is efficient for the problem of large sizes.","PeriodicalId":447825,"journal":{"name":"Vinh University Journal of Science","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124895798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The IT-based management of training activities at universities has many inadequacies. According to the facilitation of comprehensive IT system application under digital transformation in education sector with the aim of smart-university driven model application, this paper provides a systematic view of a smart university, and analyses some issues related to IT-based training management, which supports Vietnamese universities to integrate smart-university driven management systems.
{"title":"IT-based smart-university driven management of higher education training activities","authors":"LE Van Tan","doi":"10.56824/vujs.2022ed11","DOIUrl":"https://doi.org/10.56824/vujs.2022ed11","url":null,"abstract":"The IT-based management of training activities at universities has many inadequacies. According to the facilitation of comprehensive IT system application under digital transformation in education sector with the aim of smart-university driven model application, this paper provides a systematic view of a smart university, and analyses some issues related to IT-based training management, which supports Vietnamese universities to integrate smart-university driven management systems.","PeriodicalId":447825,"journal":{"name":"Vinh University Journal of Science","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128416230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
VO Thi Minh Ngoc, Tran Viet Thanh, Chu Thi Hoai Sam, Le Tran Bao Tran, Dang Van Trong, Nguyễn Thi Thuy, Le Van Hieu, Chu Van Lanh
In this paper, we present a new design of solid-core photonic crystal fiber (PCF), a Ge20Sb5Se75 substrate with a hexagonal lattice structure. The fiber characteristics are studied in the long-wavelength range (from 1.5 µm to 7.0 µm). A full modal analysis and optical properties of designed photonic crystal fibers with lattice constant Λ and filling factor d/Λ are presented in terms of chromatic dispersion, effective refractive index, nonlinear coefficients, and confinement loss. All-normal and anomalous flat dispersion with high nonlinearity and low confinement loss are the outstanding advantages of these photonic crystalline fibers. From there, three optimal structures with Ʌ = 2.0 µm, d/Ʌ = 0.35; Ʌ = 2.5 µm, d/Ʌ = 0.3 and Ʌ = 3.0 µm, d/Ʌ = 0.3 are selected and analyzed in detail for application in supercontinuum (SC) generation.
{"title":"Optimization of optical properties of Ge20Sb5Se75-based photonic crystal fibers","authors":"VO Thi Minh Ngoc, Tran Viet Thanh, Chu Thi Hoai Sam, Le Tran Bao Tran, Dang Van Trong, Nguyễn Thi Thuy, Le Van Hieu, Chu Van Lanh","doi":"10.56824/vujs.2022nt16","DOIUrl":"https://doi.org/10.56824/vujs.2022nt16","url":null,"abstract":"In this paper, we present a new design of solid-core photonic crystal fiber (PCF), a Ge20Sb5Se75 substrate with a hexagonal lattice structure. The fiber characteristics are studied in the long-wavelength range (from 1.5 µm to 7.0 µm). A full modal analysis and optical properties of designed photonic crystal fibers with lattice constant Λ and filling factor d/Λ are presented in terms of chromatic dispersion, effective refractive index, nonlinear coefficients, and confinement loss. All-normal and anomalous flat dispersion with high nonlinearity and low confinement loss are the outstanding advantages of these photonic crystalline fibers. From there, three optimal structures with Ʌ = 2.0 µm, d/Ʌ = 0.35; Ʌ = 2.5 µm, d/Ʌ = 0.3 and Ʌ = 3.0 µm, d/Ʌ = 0.3 are selected and analyzed in detail for application in supercontinuum (SC) generation.","PeriodicalId":447825,"journal":{"name":"Vinh University Journal of Science","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130988388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
LE Thi Tuyet Hanh, Tran Thi Khanh Tung, Nguyen Vo Hoang
This study shows an attempt to investigate the listening problems encountered by English-major students from Vinh university and then explored whether there exist inter-relations between English listening activities and English listening tests. A questionnaire is administered and sent out to 193 English-major students and the follow-up interviews are conducted to specify the findings. The results indicate that the students struggled with listening skills due to three main sources: speakers, listeners and materials. In addition, the findings also reveal that English listening activities are mostly aligned with given English listening test items. Finally, pedagogical implications are proposed to help EFL students enhance their listening skills and teachers to adjust their teaching methods appropriately.
{"title":"Listening difficulties faced by EFL students and inter-relations between listening activities and tests","authors":"LE Thi Tuyet Hanh, Tran Thi Khanh Tung, Nguyen Vo Hoang","doi":"10.56824/vujs.2022ed12","DOIUrl":"https://doi.org/10.56824/vujs.2022ed12","url":null,"abstract":"This study shows an attempt to investigate the listening problems encountered by English-major students from Vinh university and then explored whether there exist inter-relations between English listening activities and English listening tests. A questionnaire is administered and sent out to 193 English-major students and the follow-up interviews are conducted to specify the findings. The results indicate that the students struggled with listening skills due to three main sources: speakers, listeners and materials. In addition, the findings also reveal that English listening activities are mostly aligned with given English listening test items. Finally, pedagogical implications are proposed to help EFL students enhance their listening skills and teachers to adjust their teaching methods appropriately.","PeriodicalId":447825,"journal":{"name":"Vinh University Journal of Science","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124161202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Le Tran Bao Tran, Dang Van Trong, Truong Thi Chuyen Oanh, Nguyễn Thi Thuy, Chu Van Lanh
In this research, new circular and hexagonal photonic crystal fibers (PCFs) filled with chloroform have been designed considering the difference in air hole diameters to optimize the characteristics of the fiber simultaneously. Effective mode area and confinement loss of five PCFs with optimal dispersion have been further studied to find the fiber with a great application value for supercontinuum generation (SCG). Generally, circular PCFs are dominant over hexagonal lattices because of their small effective mode area, low loss, and small dispersion. #CF1 fiber with a lattice constant (Ʌ) of 1.0 μm and filling factor (d1/Ʌ) of 0.65 has an all-normal dispersion with a low value of -1.623 ps/nm/km, a small effective mode area of 1.43 µm2, and a low loss of 2.472 dB/m at 0.945 µm. The effective mode area and confinement loss of #CF2 (Ʌ = 1.0 µm, d1/Ʌ = 0.7) are the smallest of proposed PCFs. #HF1 fiber (Ʌ = 1.0 µm, d1/Ʌ = 0.5) has a very flat dispersion curve in the 1-2 µm wavelength range and a rather small effective mode area. These are the most optimal fibers for two types of lattices, which are very suitable for near-infrared SCG.
{"title":"Comparison of effective mode area and confinement loss of chloroform-core photonic crystal fibers with circular and hexagonal lattices","authors":"Le Tran Bao Tran, Dang Van Trong, Truong Thi Chuyen Oanh, Nguyễn Thi Thuy, Chu Van Lanh","doi":"10.56824/vujs.2022nt13","DOIUrl":"https://doi.org/10.56824/vujs.2022nt13","url":null,"abstract":"In this research, new circular and hexagonal photonic crystal fibers (PCFs) filled with chloroform have been designed considering the difference in air hole diameters to optimize the characteristics of the fiber simultaneously. Effective mode area and confinement loss of five PCFs with optimal dispersion have been further studied to find the fiber with a great application value for supercontinuum generation (SCG). Generally, circular PCFs are dominant over hexagonal lattices because of their small effective mode area, low loss, and small dispersion. #CF1 fiber with a lattice constant (Ʌ) of 1.0 μm and filling factor (d1/Ʌ) of 0.65 has an all-normal dispersion with a low value of -1.623 ps/nm/km, a small effective mode area of 1.43 µm2, and a low loss of 2.472 dB/m at 0.945 µm. The effective mode area and confinement loss of #CF2 (Ʌ = 1.0 µm, d1/Ʌ = 0.7) are the smallest of proposed PCFs. #HF1 fiber (Ʌ = 1.0 µm, d1/Ʌ = 0.5) has a very flat dispersion curve in the 1-2 µm wavelength range and a rather small effective mode area. These are the most optimal fibers for two types of lattices, which are very suitable for near-infrared SCG.","PeriodicalId":447825,"journal":{"name":"Vinh University Journal of Science","volume":"473 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127552515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The decision to choose a destination of tourists is influenced by many factors. Conducting research on these factors is an urgent issue to evaluate accurately and objectively the factors affecting the choice of the destination of the tourist. In this research the Exploratory Factor Analysis (EFA) has been used to build a model to evaluate the factors afectting the choice of destination in Phan Thiet city of domestic tourists. The results show that there are 3 factors, including pulling and pushing motivation, price, publicity with different levels of impact. A number of suitable solutions to attract tourists to Phan Thiet have been developed.
{"title":"Analysis of factors affecting the decision to choose Phan Thiết City of domestic travelers","authors":"Nguyen Thi Binh","doi":"10.56824/vujs.2022sh08","DOIUrl":"https://doi.org/10.56824/vujs.2022sh08","url":null,"abstract":"The decision to choose a destination of tourists is influenced by many factors. Conducting research on these factors is an urgent issue to evaluate accurately and objectively the factors affecting the choice of the destination of the tourist. In this research the Exploratory Factor Analysis (EFA) has been used to build a model to evaluate the factors afectting the choice of destination in Phan Thiet city of domestic tourists. The results show that there are 3 factors, including pulling and pushing motivation, price, publicity with different levels of impact. A number of suitable solutions to attract tourists to Phan Thiet have been developed.","PeriodicalId":447825,"journal":{"name":"Vinh University Journal of Science","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131112063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Curriculum is an important factor when researching an educational model, a training institution or any content related to education. Understanding the curriculum comprehensively and deeply as well as grasping curriculum development trends will help educators have clearer orientations. The article focuses on clarifying the concept of curriculum, approaches to curriculum, classification of curriculum, phases of curriculum development, general elements of the curriculum framework and current trends in curriculum development.
{"title":"Curriculum and development trends","authors":"Pham Thi Le Quyen","doi":"10.56824/vujs.2022ed09","DOIUrl":"https://doi.org/10.56824/vujs.2022ed09","url":null,"abstract":"Curriculum is an important factor when researching an educational model, a training institution or any content related to education. Understanding the curriculum comprehensively and deeply as well as grasping curriculum development trends will help educators have clearer orientations. The article focuses on clarifying the concept of curriculum, approaches to curriculum, classification of curriculum, phases of curriculum development, general elements of the curriculum framework and current trends in curriculum development.","PeriodicalId":447825,"journal":{"name":"Vinh University Journal of Science","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125940471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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