THU DAU MOT UNIVERSITY
Journal of Science

journal homepage: ejs.tdmu.edu.vn

ISSN 2615-9635

Aims and Scope

Thu Dau Mot University Journal of Science (EJS) is published by Thu Dau Mot University under the authorization of Ministry of Information and Communications to serve the interests of both Vietnam and international lectures and scientists associated with higher education, postgraduate training and scientific research for community. The aim is to publish high quality research papers in a variety of fields of social sciences, such as humanities, education and economics. The Journal, which is a forum for the presentation of innovative ideas, approaches, and research projects, facilitates knowledge exchange among lecturers, researchers, and education professionals. We accept submissions of articles which report new outcome of empirical research, review of the field, and discourse of scholarly debate. This is an online quarterly multi-discipline journal, which is schedules to be published on January 15, April 15, July 15 and October 15 of every year. The following areas of disciplines are to be covered in the Journal: (1) Natural Science, (2) Social Science & Humanities, (3) Technology Engineering, (5) Economics, (6) Management, (7) Education, and (8) Other areas in the development of high Education.

Current Issue
Students’ difficulties in learning English for specific purpose grammar at the People’s Police University
by Le Huong Hoa, Le Quang Truc (People’s Police University)
Article Info: Received 11 Nov. 2019, Accepted 24 Dec. 2019, Available online 15 Feb. 2020
Corresponding author: hoalehuong@yahoo.com (Le Huong Hoa PhD)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.001

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This study investigated grammatical difficulties encountered by students of the People’s Police University while learning grammar in ESP courses. The design included questionnaires to teachers and students, and classroom participant observations. The findings indicated that the student respondents only perceived four target features to be difficult to learn. The results also showed that the students’ perceptions of grammatical difficulty were influenced by several factors including the inherent complexity of rules, L1 transfer, students’ differences in language aptitude, students’ infrequency of practice, and teaching methodology. The findings will hopefully be useful for teachers and researchers with an interest in this line of research.

Key words: grammatical features, perceived, ESP grammar.

A study of fixed points and hopf bifurcation of hindmarsh-rose model
by Phan Van Long Em (An Giang university, Vietnam)
Article Info: Received 10 Sep. 2019, Accepted 20 Oct. 2019, Available online 15 Feb. 2020
Corresponding author: pvlem@agu.edu.vn (Phan Van Long Em PhD)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.002

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In this article, a class of Hindmarsh-Rose model is studied. First, all necessary conditions for the parameters of system are found in order to have one stable fixed point which presents the resting state for this famous model. After that, using the Hopf’s theorem proofs analytically the existence of a Hopf bifurcation, which is a critical point where a system’s stability switches and a periodic solution arises. More precisely, it is a local bifurcation in which a fixed point of a dynamical system loses stability, as a pair of complex conjugate eigenvalues cross the complex plane imaginary axis. Moreover, with the suitable assumptions for the dynamical system, a small-amplitude limit cycle branches from the fixed point.

 

Keywords: Hindmarsh-Rose model, fixed point, Hopf bifurcation, limit cycle

Assessment of the effects of organic solvent to the health of workers in Printer - case study of Fuji Seal Vietnam Company, in VSIP II industrial park, Binh Duong province
by Truong Quoc Minh, Nguyen Hien Than (Thu Dau Mot University, Vietnam)
Article Info: Received 03 Sep. 2019, Accepted 20 Nov. 2019, Available online 15 Feb. 2020
Corresponding author: minhtq@tdmu.edu.vn (Truong Quoc Minh M.A.)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.003

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ABSTRACT

The study was conducted at Fuji Seal Vietnam Co., Ltd. to examine the exposure and health risks of workers working in the printing and ink phase area when exposed to solvent vapor through the respiratory apparatus Toluene, Methyl Ethyl Ketone, Ethyl Acetate, Isopropyl Acohol. The results show that: During the monitoring period from July to November 2016, the amount of solvent vapor in the printing area and ink phase is quite high, at the highest Toluene printing area, it was 2.63 times higher than the standard equal to the health risk HQ male is 2.61 and HQ female is 3.37; Ethyl Acetate exceeded the highest of 4.34 times equal to the male HQ risk ratio of 4.29 and female HQ equal to 5.53; MEK exceeds 8.43 times equal to the health risk HQ male is 8.36 and HQ female is 10.79;  Isopropyl Acohol exceeds 8.4 times equal to the health risk HQ male is 8.33 and HQ female is 10.75; At the inking area, MEK exceeds 8.43 times equal to the health risk HQ male is 8.36 and HQ female is 10.79. From the calculated data - analysis, found that the health of workers working in the printing and inking areas had high risks, the ability of workers suffering from diseases such as headache, dizziness, skin damage,... and especially respiratory failure.

Key words: Fuji Seal Company, health risks, solvent vapor

Methylene orange handling of cock cake casted by H3Po4 chemicals
by Dao Minh Trung, Nguyen Thi Tuyet Ngan, Nguyen Thanh Quang, Le Thi Dao, Trinh Diep Phuong Danh (Thu Dau Mot University, Vietnam)
Article Info: Received 05 Nov. 2019, Accepted 20 Dec. 2019, Available online 15 Feb. 2020
Corresponding author: trungdm@tdmu.edu.vn (Dao Minh Trung PhD)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.004

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ABSTRACT

Survey of methylene orange wastewater treatment by activated carbon material prepared from macadamia husk with chemical activator H3PO4 shows that coal with the best methylene orange color treatment is achieved Optimal conditions such as pH = 5, coal dose 0.9 g/L and time 120 minutes. The results show that it is applicable to color wastewater treatment and the results are similar to other research results.

 

Key words: Activated carbon H3PO4, Macadamia, adsorption, Methylene Orange.

Investigation of Zn2+ heavy metal handling ability by macadamite activated by H3PO4
by Dao Minh Trung, Tran Phuoc Dong, Trinh Diep Phương Danh (Thu Dau Mot University, Vietnam)
Article Info: Received 30 Oct. 2019, Accepted 15 Dec. 2019, Available online 15 Feb. 2020
Corresponding author: trungtd@tdmu.edu.vn (Dao Minh Trung PhD)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.005

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ABSTRACT

Investigate the possibility of treating wastewater containing heavy metals Zn2+ with activated carbon material prepared from macadamia shell with chemical activating agent H3PO4, showing high efficiency of adsorption of Zn2+. The results of the study showed that activated carbon with H3PO4 activating agent has high adsorption capacity, capable of handling Zn2+ best at pH = 4.5, dosage 1.8 g/L and time is 120 minutes. . The results show similarities with other research results and are capable of treating wastewater containing heavy metals Zn2+.

 

Key word: Macadamia, metal processing, H3PO4, activated carbon

Survey of zinc metal processing capability with coal-chemistry activated carbon by chemical K2CO3
by Dao Minh Trung, Tran Thi Bich Tram, Le Thi Dao, Trinh Diep Phuong Danh (Thu Dau Mot University, Vietnam)
Article Info: Received 11 Nov. 2019, Accepted 24 Dec. 2019, Available online 15 Feb. 2020
Corresponding author: trungtd@tdmu.edu.vn (Dao Minh Trung PhD)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.006

| PDF

ABSTRACT

Seed coat macadamia preparation of activated carbon with chemical agent K2CO3 from macadamia shells as per ratio: K2CO3: distilled water = 1:1:10ml, optimal temperature condition 6500C and burning time 60 minutes. Efficiency removal of zinc (II) in wastewater efficiency (53.42%) with the concentration of 25ppm, conducted a survey at pH = 4.5 with 1.8g/l of carbon, treated in 100 minutes. Survey results have similarities with other studies and are applicable to application removal of zinc (II) in wastewater.

 

Key words: Activated carbon, adsorbed Zn2+, K2CO3, Macadamia

Application of simulation in 3D space to teaching and science research
by Ngo Bao (Thu Dau Mot University, Vietnam)
Article Info: Received 30 Nov. 2019, Accepted 15 Jan. 2020, Available online 15 Feb. 2020
Corresponding author: baon@tdmu.edu.vn (Ngo Bao M.A.)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.007

| PDF

ABSTRACT

This article introduces the general issues and benefits of simulation in teaching and scientific research. Thereby, the author illustrates by making 3D drawings, assemblies, videos simulating machine structures for teaching Theoretical mechanics, Construction machine subjects and the author's studies in the mechanical field.

The application of simulation in teaching is to create videos by using Solidworks software, simulating the operating principle of machine structures. After that, show the videos to the students, excite them and make the lesson lively. And the simulation application in scientific research is mentioned as the way to use 3D drawings and simulation videos to preview the research results, promptly fix the wrong places. Since then, the research is quick, cost reduction is not worth it.

The results of this paper are to point out the unique benefits that contribute positively to simulation in teaching and in scientific research.

 

Key words: cranes, figures, hoists, schemas, simulations

Students’ difficulties in learning English for specific purpose grammar at the People’s Police University
by Le Huong Hoa, Le Quang Truc (People’s Police University)
Article Info: Received 11 Nov. 2019, Accepted 24 Dec. 2019, Available online 15 Feb. 2020
Corresponding author: hoalehuong@yahoo.com (Le Huong Hoa PhD)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.001

| PDF

This study investigated grammatical difficulties encountered by students of the People’s Police University while learning grammar in ESP courses. The design included questionnaires to teachers and students, and classroom participant observations. The findings indicated that the student respondents only perceived four target features to be difficult to learn. The results also showed that the students’ perceptions of grammatical difficulty were influenced by several factors including the inherent complexity of rules, L1 transfer, students’ differences in language aptitude, students’ infrequency of practice, and teaching methodology. The findings will hopefully be useful for teachers and researchers with an interest in this line of research.

Key words: grammatical features, perceived, ESP grammar.

A study of fixed points and hopf bifurcation of hindmarsh-rose model
by Phan Van Long Em (An Giang university, Vietnam)
Article Info: Received 10 Sep. 2019, Accepted 20 Oct. 2019, Available online 15 Feb. 2020
Corresponding author: pvlem@agu.edu.vn (Phan Van Long Em PhD)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.002

| PDF

In this article, a class of Hindmarsh-Rose model is studied. First, all necessary conditions for the parameters of system are found in order to have one stable fixed point which presents the resting state for this famous model. After that, using the Hopf’s theorem proofs analytically the existence of a Hopf bifurcation, which is a critical point where a system’s stability switches and a periodic solution arises. More precisely, it is a local bifurcation in which a fixed point of a dynamical system loses stability, as a pair of complex conjugate eigenvalues cross the complex plane imaginary axis. Moreover, with the suitable assumptions for the dynamical system, a small-amplitude limit cycle branches from the fixed point.

 

Keywords: Hindmarsh-Rose model, fixed point, Hopf bifurcation, limit cycle

Assessment of the effects of organic solvent to the health of workers in Printer - case study of Fuji Seal Vietnam Company, in VSIP II industrial park, Binh Duong province
by Truong Quoc Minh, Nguyen Hien Than (Thu Dau Mot University, Vietnam)
Article Info: Received 03 Sep. 2019, Accepted 20 Nov. 2019, Available online 15 Feb. 2020
Corresponding author: minhtq@tdmu.edu.vn (Truong Quoc Minh M.A.)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.003

| PDF

ABSTRACT

The study was conducted at Fuji Seal Vietnam Co., Ltd. to examine the exposure and health risks of workers working in the printing and ink phase area when exposed to solvent vapor through the respiratory apparatus Toluene, Methyl Ethyl Ketone, Ethyl Acetate, Isopropyl Acohol. The results show that: During the monitoring period from July to November 2016, the amount of solvent vapor in the printing area and ink phase is quite high, at the highest Toluene printing area, it was 2.63 times higher than the standard equal to the health risk HQ male is 2.61 and HQ female is 3.37; Ethyl Acetate exceeded the highest of 4.34 times equal to the male HQ risk ratio of 4.29 and female HQ equal to 5.53; MEK exceeds 8.43 times equal to the health risk HQ male is 8.36 and HQ female is 10.79;  Isopropyl Acohol exceeds 8.4 times equal to the health risk HQ male is 8.33 and HQ female is 10.75; At the inking area, MEK exceeds 8.43 times equal to the health risk HQ male is 8.36 and HQ female is 10.79. From the calculated data - analysis, found that the health of workers working in the printing and inking areas had high risks, the ability of workers suffering from diseases such as headache, dizziness, skin damage,... and especially respiratory failure.

Key words: Fuji Seal Company, health risks, solvent vapor

Methylene orange handling of cock cake casted by H3Po4 chemicals
by Dao Minh Trung, Nguyen Thi Tuyet Ngan, Nguyen Thanh Quang, Le Thi Dao, Trinh Diep Phuong Danh (Thu Dau Mot University, Vietnam)
Article Info: Received 05 Nov. 2019, Accepted 20 Dec. 2019, Available online 15 Feb. 2020
Corresponding author: trungdm@tdmu.edu.vn (Dao Minh Trung PhD)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.004

| PDF

ABSTRACT

Survey of methylene orange wastewater treatment by activated carbon material prepared from macadamia husk with chemical activator H3PO4 shows that coal with the best methylene orange color treatment is achieved Optimal conditions such as pH = 5, coal dose 0.9 g/L and time 120 minutes. The results show that it is applicable to color wastewater treatment and the results are similar to other research results.

 

Key words: Activated carbon H3PO4, Macadamia, adsorption, Methylene Orange.

Investigation of Zn2+ heavy metal handling ability by macadamite activated by H3PO4
by Dao Minh Trung, Tran Phuoc Dong, Trinh Diep Phương Danh (Thu Dau Mot University, Vietnam)
Article Info: Received 30 Oct. 2019, Accepted 15 Dec. 2019, Available online 15 Feb. 2020
Corresponding author: trungtd@tdmu.edu.vn (Dao Minh Trung PhD)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.005

| PDF

ABSTRACT

Investigate the possibility of treating wastewater containing heavy metals Zn2+ with activated carbon material prepared from macadamia shell with chemical activating agent H3PO4, showing high efficiency of adsorption of Zn2+. The results of the study showed that activated carbon with H3PO4 activating agent has high adsorption capacity, capable of handling Zn2+ best at pH = 4.5, dosage 1.8 g/L and time is 120 minutes. . The results show similarities with other research results and are capable of treating wastewater containing heavy metals Zn2+.

 

Key word: Macadamia, metal processing, H3PO4, activated carbon

Survey of zinc metal processing capability with coal-chemistry activated carbon by chemical K2CO3
by Dao Minh Trung, Tran Thi Bich Tram, Le Thi Dao, Trinh Diep Phuong Danh (Thu Dau Mot University, Vietnam)
Article Info: Received 11 Nov. 2019, Accepted 24 Dec. 2019, Available online 15 Feb. 2020
Corresponding author: trungtd@tdmu.edu.vn (Dao Minh Trung PhD)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.006

| PDF

ABSTRACT

Seed coat macadamia preparation of activated carbon with chemical agent K2CO3 from macadamia shells as per ratio: K2CO3: distilled water = 1:1:10ml, optimal temperature condition 6500C and burning time 60 minutes. Efficiency removal of zinc (II) in wastewater efficiency (53.42%) with the concentration of 25ppm, conducted a survey at pH = 4.5 with 1.8g/l of carbon, treated in 100 minutes. Survey results have similarities with other studies and are applicable to application removal of zinc (II) in wastewater.

 

Key words: Activated carbon, adsorbed Zn2+, K2CO3, Macadamia

Application of simulation in 3D space to teaching and science research
by Ngo Bao (Thu Dau Mot University, Vietnam)
Article Info: Received 30 Nov. 2019, Accepted 15 Jan. 2020, Available online 15 Feb. 2020
Corresponding author: baon@tdmu.edu.vn (Ngo Bao M.A.)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.007

| PDF

ABSTRACT

This article introduces the general issues and benefits of simulation in teaching and scientific research. Thereby, the author illustrates by making 3D drawings, assemblies, videos simulating machine structures for teaching Theoretical mechanics, Construction machine subjects and the author's studies in the mechanical field.

The application of simulation in teaching is to create videos by using Solidworks software, simulating the operating principle of machine structures. After that, show the videos to the students, excite them and make the lesson lively. And the simulation application in scientific research is mentioned as the way to use 3D drawings and simulation videos to preview the research results, promptly fix the wrong places. Since then, the research is quick, cost reduction is not worth it.

The results of this paper are to point out the unique benefits that contribute positively to simulation in teaching and in scientific research.

 

Key words: cranes, figures, hoists, schemas, simulations

Quality assurance in Vietnam’s higher education: Insights into past and present challenges
by Nguyễn Văn Hiệp (Thu Dau Mot University)
Article Info: Received 15 Aug. 2019, Accepted 24 Sep. 2019, Available online 15 Oct. 2019
Corresponding author: hiepvn@tdmu.edu.vn (Prof. Nguyễn Văn Hiệp)
Doi:

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Vietnam higher education has attempted innovations in increased efforts to integrate well into the world’s education. One of the most prominent innovative activities is quality assurance. Adopting a historical approach, this paper presents the Vietnam higher education quality assurance renovating process including three phases: the centrally planned economy period (1954–1986), the reform period (1986–2000) and the international integration period (2000–2017). At each stage, it is referred to the perspective, the system, the mechanism, and the achievements of Vietnam higher education quality assurance. By taking a historical stance, the paper presented the continued advance of higher education management, the role and significance of quality assurance as an integration commitment of Vietnam education in the context of globalization.
Keywords: higher education, quality assurance, training, Vietnam
Southeast region of Vietnam - Space identification through administrative boundary
by Phạm Văn Thịnh (Thu Dau Mot University)
Article Info: Received 18 Aug. 2019, Accepted 26 Sep. 2019, Available online 15 Oct. 2019
Corresponding author: thinhpv@tdmu.edu.vn (MA. Phạm Văn Thịnh)
Doi:

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The Southeast region, in prehistory and protohistory, established the space of Dong Nai archeological culture. Since the 16th to 17th centuries, the Southeast had been discovered by the Vietnamese people, in which they established sovereignty and administrative structure. Over three centuries of formation and development, the Southeast region has created many changes in geographic names and administrative structures as required by the historical context of each period. This article presents the overview of the administrative restructuring process in the Southeast region in some important historical milestones during the development process hereof. With the presentation of administrative structures in the Southeast region, the article contributes to systemizing the historical periods of formation and development of the region. It also opens further dialogues for the study of historical and cultural characteristics of the Southeast region.

Keywords: administrative structure, Gia Dinh Department, prehistory and protohistory, Southeast region

The Southeast of Vietnam as a cultural zone and roles of culture - people in the sustainable development of the region
by Trần Ngọc Thêm (University of Social Sciences and Humanities, VNU-HCM)
Article Info: Received 15 Aug. 2019, Accepted 24 Sep. 2019, Available online 15 Oct. 2019
Corresponding author: ngocthem@gmail.com (Prof. Dr.Sc. Trần Ngọc Thêm)
Doi:

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The Southeast plays a very important role in Vietnam’s economic development. Although social science researchers are well located in the Southeast, there remains a paradox that the Southeast culture has not been sufficiently researched into. Applying the method of culture zoning based on three-dimensional change of Subject - Space - Time developed by the author, the article concludes that the Southeast is a separate cultural zone besides the Southwest and lists some typical characteristics of Southeast in terms of the cultural elements (focusing on the organizational culture) and the system of cultural personality characteristics of Vietnamese people in the Southeast. The analysis of Human Development Index (HDI) of Southeast shows that this development is unbalanced and unsustainable. To achieve the balance and sustainability, the Southeast needs to focus on investing in the cultural and human development; reduce the village community and replace it with the social community; minimize the rural nature, agriculture, farmers and enhance the urban civilization, industrial culture and citizens.

Keywords: cultural zone, roles of culture, sustainable development, Southeast

 
Occupation-based social structure in Binh Duong Province, 1999-2009
by Bùi Thế Cường (Thu Dau Mot Universtiy), Vũ Mạnh Lợi (Vietnam Academy of Social Sciences)
Article Info: Received 10 Aug. 2019, Accepted 30 Sep. 2019, Available online 15 Oct. 2019
Corresponding author: cuongbuithe@yahoo.com (Prof. Cuong Bui The)
Doi:

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Binh Duong has rapidly transformed during the period 1999-2009, from a agricultural province to industrial one. The paper explores the shift of occupationbased social structure of Binh Duong during that period. Using the data sets of Census 1999 and 2009, the paper analyses the evolution of the occupational figure in Binh Duong by ten occupational categories and four occupational strata, and the differences in this figure by residence, gender, ethnic, and religious variables. Findings show that the occupational structure of Binh Duong is more developed than the one of the Southern Key Economic Zone. Its change in rural areas is more significant than in urban areas. There are not considerable differences by gender, ethnicity, and religiousness. The findings are suggestive for a further analysis using the data set of Census 2019 on the evolution of occupational figures in Binh Duong during the previous twenty years (1999-2019).

Keywords: Binh Duong, occupational structure, occupation-based social structure, occupational strata, social structure

 
Cultural practices of the Khmer in Binh Duong - Historical particularism approach
by Trần Hạnh Minh Phương (Thu Dau Mot University)
Article Info: Received 15 Aug. 2019, Accepted 24 Sep. 2019, Available online 15 Oct. 2019
Corresponding author: phuongthm@tdmu.edu.vn (Dr. Trần Hạnh Minh Phương)
Doi:

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In 2014, Binh Duong has 2.885 the Khmer people, being the second largest ethnic minority compared to the Hoa people. They have contributed to the multi-ethnic culture of Binh Duong. Hundreds of works on the Khmer in the Mekong Delta considered their culture as a typical of Theravada Buddhist culture in Vietnam but this proposition is not suitable for the Khmer community in An Binh, Phu giao district who is this object of this study. By qualitative data sources from in-depth interviews, participant observations and approach to the historical particularism, this study documented the cultural characteristics of the Khmer in An Binh and analyzed the factors that make culture of the Khmer in An Binh different from the culture of the Khmer in the Mekong Delta. Natural conditions and socio-historical context make the cultural practices of the Khmer in An Binh more similar to the culture of the ethnic groups in the Central Highlands than the Khmer culture in the Mekong delta, especially, customs and folk beliefs.

Keywords: the Khmer culture, the Khmer in Binh Duong, cultural practices

Interpretations about Hoa Anh state
by Nguyễn Văn Giác (Thu Dau Mot University)
Article Info: Received 15 Aug. 2019, Accepted 24 Sep. 2019, Available online 15 Oct. 2019
Corresponding author: vanjack.nguyen@gmail.com (PhD. Nguyễn Văn Giác)
Doi:

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On the basis of coordinating the sources of history materials from Vietnam and China, together with the latest archaeological achievements of Ho citadel, the article has delineated territory, confirmed the chronology frame with the Kings of this kingdom in relation to post-Champa Empire. It is from the aftermath of Vijaya, the two parts of Aryaru (Phu Yen) and Kauthara (Khanh Hoa) belong to Hoa Anh Kingdom, in which, Le Thanh Tong is crowned as Ban La Tra Duyet; the rebellion of this King is the cause for the second conquest, formally taking Ling Chan/ Da Bia as the landmark; Trai A Ma Phat Am is designated as Hoa Anh’s King on the remaining land of Kauthara, but immediately incorporated into Panduranga, forming the state of postChampa.

Keywords: Hoa Anh kingdom, Da Bia mountain, Maha Ban La Tra Duyet, post-Champa