Distribution of the Tax Burden across Companies in Vietnam: The Issue of Corporate Tax Avoidance

Kien Trung TRAN(Kien Trung TRAN ) 한국유통과학회 2023 유통과학연구 Vol.21 No.6

Study on sintering process of woodceramics from the cashew nutshell waste

Kieu Do Trung Kien,Phan DinhTuan,Toshihiro Okabe,Do Quang Minh,Tran Van Khai 한양대학교 세라믹연구소 2018 Journal of Ceramic Processing Research Vol.19 No.6

In this study, the sintering mechanism of woodceramics (WCs) from cashew nut shell waste (CNSW) was studied by analyzingchemical reactions and structural changes during the sintering process of of CNSW powder, liquefied wood and green bodiesof WCs at 900 oC for 60 minutes in the CO2 atmosphere. The chemical and structural properties of the products wereinvestigated by X-ray diffraction (XRD), Raman spectroscopy, Fourier Transform Infrared (FTIR), and scanning electronmicroscope (SEM). The results showed that the decomposition reactions of liquefied wood and CNSW occurred simultaneouslyto form the hard carbon and the soft carbon at high temperature. The sintering mechanism of WCs has been presented.

Power Control in the Dynamic Wireless Charging of Electric Vehicles

Nguyen Thi Diep,Nguyen Kien Trung,Tran Trong Minh 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

This paper proposes a new power control method which is able to control the varying charging power according to the state of charge of the battery in the dynamic wireless charging of electric vehicle. The advantage is that the dual-side wireless communication is avoided. A dual-loop primary controller is proposed to regulate the charging power which only employs the primary side controller. The information on system parameters and the coupling coefficients are required. However, in the dynamic wireless charging the coupling coefficients change continuously. This paper also presents the coupling coefficients estimation method from the primary side. The simulation and experimental results validate the feasibility of the proposed control method. A 1.5 kW dynamic charging prototype is constructed. The experimental results show that the output power is adjustable in dynamic charging process with error less than 0.2% and the system maximum efficiency from dc source to the optimal load reaches 89.5%.

Factors Influencing Business Efficiency of Steel Firms: Evidence from Vietnam

Nguyet Minh NGUYEN,Kien Trung TRAN 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.1

This study aims to identify and analyze the impact of internal factors on business efficiency of steel firms in Vietnam. The article uses data collected from the financial statements of 26 steel firms operating in Vietnam between 2012 and 2019. With the application of E-view software in quantitative analysis to build regression models on the table data (panel data), and the study has built a regression model identifying the relationship and impact level of internal factors affecting business efficiency of steel firms in Vietnam. In the study, the dependent variable is business efficiency, determined by the profit after tax on the firm’s assets. The independent variables are firm size, growth rate, capital structure, ratio of long-term assets, receivables management, and solvency. The research results show that the four factors of firm size, growth rate of assets, receivables management, and solvency have a positive impact on business efficiency, while two factors including capital structure and ratio of long-term assets do not affect business efficiency of enterprises. The results of this article are very useful for corporate executives in general and for financial managers in particular, helping managers make the right financial decisions for the company to promote business efficiency of the company.

Factors Affecting Capital Structure of Listed Construction Companies on Hanoi Stock Exchange

Nguyet Minh NGUYEN,Kien Trung TRAN 한국유통과학회 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.11

The aim of this article is to determine the influence of factors on the capital structure of construction companies listed on the Hanoi Stock Exchange. The data of the article were collected and calculated from the financial statements of 54 construction companies listed on Hanoi Stock Exchange from 2012 to 2019. With the application of E-view software in quantitative analysis to build panel data regression model (panel data), the article has built a regression model to determine the relationship of intrinsic factors affecting the capital structure of construction companies listed on Hanoi Stock Exchange. In the study, dependent variable is capital structure, determined by the debt-toequity ratio. Profitability, coefficient of solvency, size, loan interest rate, structure of tangible assets, and growth are independent variables. The results showed that the two factors of growth and firm size positively affect the capital structure, the profitability factor has the opposite effect on capital structure. Factors of short-term debt solvency, average loan interest rate and tangible asset structure have no correlation with capital structure. The findings of this article are useful for business administrators, helping business managers make the right financial decisions to make capital structure decisions in their own conditions.

Effect of composition on the ability to form SiC/SiO2-C composite from rice husk and silica gel

Do Quang Minh,Tran Van Khai,Huynh Ngoc Minh,Nguyen Vu Uyen Nhi,Kieu Do Trung Kien 한양대학교 세라믹연구소 2021 Journal of Ceramic Processing Research Vol.22 No.2

Rice husk is a waste product of agricultural production of rice. Every year, the agricultural production of Vietnam emits about10 million tons of rice husks. Rice husks are usually treated by burning method or discharged into rivers, causing manynegative impacts on the environment. In this study, the rice husk/silica gel ratio components were investigated to form SiC/SiO2-C composite in a CO2 environment at 1000 oC for 60 min. The products after pyrolysis were determined SiC, SiO2, andfree C contents according to ISO 21068-2: 2008 standards. The functional groups and mineral composition of composites wereanalyzed by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The microstructure and elementdistribution of them were observed by scanning electron microscope (SEM) and Energy-dispersive X-ray (EDX) mapping. Theresults showed that the optimum rice husk/silica gel ratio to form SiC/SiO2-C was 1.4/1. The sample after pyrolysis hadchemical composition including 14% SiC, 63% SiO2, 23% free C (%wt.) and the phase composition including amorphouscarbon, β-SiC, 6H-SiC, 4H-SiC, cristobalite. Composite SiC/SiO2-C can apply to advanced friction systems. This can be seenas an effective method to treat rice husk waste and improved the economic value of rice plants.

Maximum Efficiency in the Dynamic Wireless Charging Systems of Electric Vehicles

Nguyen Thi Diep,Nguyen Kien Trung,Tran Trong Minh 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

This paper proposes a maximum transfer efficiency control method in the dynamic wireless charging systems of electric vehicles. A secondary-side controller is proposed to keep the optimal load impedance which is varied according the receiver position. This paper also presents the coupling coefficients estimation method from the secondary side. The simulation and experimental results validate the feasibility of proposed control method. A 1.5 kW dynamic charging prototype is constructed. The simulation and experiment results show that the proposed control method improves 6% on the transfer efficiency in the case of 30% misalignment in the dynamic wireless charging system.

Controllable synthesis of MoS₂/graphene low-dimensional nanocomposites and their electrical properties

Long, Le Ngoc,Thi, Pham Tan,Trung Kien, Pham,Trung, Pham Thanh,Ohtani, Masataka,Kumabe, Yoshitaka,Tanaka, Hirofumi,Ueda, Shigenori,Lee, Hyoyoung,Thang, Phan Bach,Khai, Tran Van Elsevier 2020 APPLIED SURFACE SCIENCE - Vol.504 No.-

<P><B>Abstract</B></P> <P>In this study, a novel hydrothermal route has been developed for the synthesis of MoS<SUB>2</SUB>/graphene composite with controllable structures, in which ammonium molybdatetetrahydrate, as-prepared graphene oxide (GO), and thioacetamide were used as staring materials. Effects of Mo<SUP>4+</SUP>-to-C precursor ratios and crystalline time on the structures, components and morphologies of MoS<SUB>2</SUB>/graphene were investigated. MoS<SUB>2</SUB>/graphene samples were characterized using XRD, FESEM, HRTEM, FTIR, Raman spectroscopy, HAADF-STEM/EDS, HXPES and electrical measurements. The results show that petal-like MoS<SUB>2</SUB> nanostructures with ultrathin petals (~1–10 layers) and coexistence of 1T- and 2H-MoS<SUB>2</SUB> phases can be synthesized on graphene surface in a short time (~2 h). Comparison of crystallization conditions, we found that the crystallization time had a significant effect on the size of the MoS<SUB>2</SUB> nanopetals. The shorter the reaction time is, the thinner the petal-like MoS<SUB>2</SUB> nanoscale is. On the other hand, by adjusting the ratios of Mo<SUP>4+</SUP>to C (denoted as: MoS<SUB>2</SUB>/C (1:2), MoS<SUB>2</SUB>/C (3:2), MoS<SUB>2</SUB>/C (2.5:1) and MoS<SUB>2</SUB>/C (3:1)), different MoS<SUB>2</SUB>/graphene architectures including “sandwich-liked”, “layer–by–layer” and “anchored” can be obtained. On the basis of these results, a possible growth mechanism of MoS<SUB>2</SUB>nanopetals on GO was proposed. Interestingly, the as-synthesized material depicts its memristive behavior through the Volt-Ampere characteristics, suggesting a potential application in logic memory devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel hydrothermal route has been developed for the synthesis of MoS<SUB>2</SUB>/graphene composite with controllable structures. </LI> <LI> The effects of Mo<SUP>4+</SUP>-to-C precursor ratios and crystalline time on properties of MoS<SUB>2</SUB>/graphene were investigated by FESEM, HRTEM, XRD, FTIR, Raman spectroscopy, HAADF-STEM/EDS and HXPES. </LI> <LI> The memristive properties of the MoS<SUB>2</SUB>/graphenenanocomposite were presented. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Micropropagation from root segments to improve seedling quality in Chinese foxglove crops

Thanh Loan Pham,Van Huy Nguyen,Thi Le Thu Hoang,Thi Tam Tien Ha,Trung Kien Tran,Xuan Duong Vu,Phi Bang Cao,Quang Trung Nguyen 한국식물생명공학회 2020 JOURNAL OF PLANT BIOTECHNOLOGY Vol.47 No.3

This is the first study to establish a complete protocol for micropropagation of Rehmannia glutinosa from root segments. The study involved investigating the effect of plant growth regulators on in vitro shoot regeneration and rooting and identifying substrates supporting survival and growth performance of ex vitro seedlings. A Murashige and Skoog (MS) medium containing 30 g/L sucrose for shoot induction and 0.2 mg/L indole-3-acetic acid (IAA), 1 mg/L 6-benzylaminopurine (BAP), and 1 g/L polyvinylpyrrolidone (PVP) for shoot multiplication resulted in the highest number of shoots per explant and shoot height. Applying a medium containing 0.5 mg/L IAA and 1 g/L PVP yielded optimal rooting of the shoots grown in vitro. Compost enriched with microbial inoculants and perlite enhanced seedling growth better than that with organic biofertilizer-free substrates (soil and sand). We recommend the continuous production of micropropagated R. glutinosa seedlings from root segments under the aforementioned conditions as a possible propagation technique for crops of this species.

Impact of Community Attachment and Resident's Support on Destination Sustainability: Evidence from Spiritual and Community Destination in Vietnam

THAN, Trong Thuy,KIEU, Thi Phuong Hoa,PHAM, Thi Anh Duong,HOANG, Thi Cam Van,TRAN, Thi Hau,NGUYEN, Huu Doan,DAO, Trung Kien Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.8

This study investigates the influence of community involvement on the destination sustainability for community destinations and spiritual destinations in Vietnam. Community involvement is measured by two constructs, which are community attachment and residents' support. A structural questionnaire consisting of 41 observation variables measured on a 5-point Likert scale was used to survey households who live in a spiritual destination in An Giang province and three community destinations in Lang Son province with the help of local tour guides and Youth Union. 168 out of 200 responses collected were valid for multivariate data analysis. The results of confirmatory factor analysis (CFA) and structural equation modeling (SEM) reveal three main findings. Firstly, community attachment has a direct effect on both perceived benefits and destination sustainability. Secondly, while residents' support has a direct effect on perceived benefits, it indirectly affects destination sustainability. Finally, community destinations have a higher level of sustainability than the spiritual destination. Based on those findings, this study proposed three suggestions for local authorities, policymakers, and residents to improve the sustainable development of their local tourism destinations, including (1) diversifying local tourism products, (2) encouraging the community participation in tourism development programs, and (3) increasing in the expected benefits in local tourism development policies.