• Title/Summary/Keyword: Vietnam National University

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Microstructure and Magnetic Properties of Au-doped Finemet-type Alloy

  • Le, Anh-Tuan;Kim, Chong-Oh;Ha Nguyen Duy;Chau Nguyen;Tho Nguyen Duc;Lee, Hee-Bok
    • Journal of Magnetics
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    • v.11 no.1
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    • pp.36-42
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    • 2006
  • In this report, we demonstrate a comprehensive analysis of the effects of Au addition on the microstructure and magnetic properties of $Fe_{73.5}Si_{13.5}B_{9}Nb_{3}Au_1$ Finemet-type alloy. It was found that the as-quenched alloys were the amorphous state and turned into nanocrystalline state under heat treatments. The DSC analysis indicates that the sharply exothermal peak corresponding to the crystallization of the $\alpha-Fe(Si)$ was observed at $547-579^{\circ}C$ depending on the heating rates, which is little higher than that of original Finemet (542-$570{^{\circ}C}$, respectively). Besides, the thermomagnetic result confirmed that the full substitution of Cu by Au with the single phase structure in the M(T) curve along cooling cycle. Ultrasoft magnetic properties of the nanocrystallized samples were significantly enhanced by the proper annealing such as the increase of permeability and the decrease of the coercivity. The optimum annealing condition was found at the annealing temperature of $540^{\circ}C$ and the increase of the annealing time up to 90 min.

The Impact of Corporate Social Responsibility on Brand Value and Financial Performance: Evidence from Bancassurance Service Providers in Vietnam

  • NGUYEN, Xuan Hung;DANG, Thuy Quynh;DINH, Thi Thao Quyen;DO, Phuong Thanh;PHAM, Thu Uyen;MAI, Duc Duong
    • The Journal of Asian Finance, Economics and Business
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    • v.9 no.6
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    • pp.183-194
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    • 2022
  • The objective of this article is to assess the impact of corporate social responsibility (CSR) implementation on Corporate Brand Value (CBV) and Corporate Financial Performance (CFP). At the same time, the article examines the mediated role of CBV on the relationship between CSR implementation and CFP. In-depth interviews and observation techniques were used in this article on 4 experts to collect qualitative information. Quantitative analysis was based on primary data obtained from 454 employees working at enterprises providing Bancassurance services. The article uses various models of Cronbach's Alpha coefficient, Exploratory Factor Analysis (EFA), Confirmatory Factor Analysis (CFA), and Structural Equation Analysis (SEM) using SPSS 22.0 and AMOS 20.0 software. In addition, a 5-point Likert scale is used to measure observed variables. Research results show that CBV plays an intermediate role in the relationship between CSR implementation and CFP. At the same time, the implementation of CSR toward communities, customers, and workers directly impacts CBV and CFP. The article draws a new conclusion; there is no relationship found between the implementation of CSR and CFP. The result proposes implications for the state and Bancassurance service providers to develop and implement CSR-related policies and activities to enhance their brand value and financial performance.

Influencing Factors of the International Payment Service Quality at Joint Stock Commercial Bank for Investment and Development of Vietnam

  • TRAN, Thi-Thu;NGO, Thi Quynh-Anh;CUNG, Thi Ngoc-Anh;NGUYEN, Thi-Giang;VU, Dang-Duong;NGUYEN, Phi-Hung;TSAI, Jung-Fa
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.10
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    • pp.241-254
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    • 2020
  • International payment is an essential part of the economy, which is beneficial to both commercial banks and trading enterprises. Moreover, service quality, which has been a key point of discussion for decades, relates to customer satisfaction. This study aims to investigate the factors influencing international payment service quality at the Join Stock Commercial Bank for Investment and Development of Vietnam (BIDV) from 2015 through 2019. This research deploys both quantitative and qualitative methods to discuss the effects of these components. Statistical data was examined through different tests, including reliability analysis, correlation, and regression analysis by SPSS 16.0. The authors obtain and analyze 157 valid responses from customer surveys, then by applying an integration SERVPERF and PSQM model, identify five main components: Reliability, Tangibles, Assurance, Convenience, and Responsiveness, which explain how the customer perceives the service quality of international payment activities at BIDV. The results show that these five factors have a positive relationship with service quality, in which, Reliability has the most significant impacts on service quality level. Besides, the findings not only contribute to the literature but also give some practical implications for BIDV to improve its international payment service quality and help them to obtain customer satisfaction in the fast-changing environment.

ROBUSTLY SHADOWABLE CHAIN COMPONENTS OF C1 VECTOR FIELDS

  • Lee, Keonhee;Le, Huy Tien;Wen, Xiao
    • Journal of the Korean Mathematical Society
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    • v.51 no.1
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    • pp.17-53
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    • 2014
  • Let ${\gamma}$ be a hyperbolic closed orbit of a $C^1$ vector field X on a compact boundaryless Riemannian manifold M, and let $C_X({\gamma})$ be the chain component of X which contains ${\gamma}$. We say that $C_X({\gamma})$ is $C^1$ robustly shadowable if there is a $C^1$ neighborhood $\mathcal{U}$ of X such that for any $Y{\in}\mathcal{U}$, $C_Y({\gamma}_Y)$ is shadowable for $Y_t$, where ${\gamma}_Y$ denotes the continuation of ${\gamma}$ with respect to Y. In this paper, we prove that any $C^1$ robustly shadowable chain component $C_X({\gamma})$ does not contain a hyperbolic singularity, and it is hyperbolic if $C_X({\gamma})$ has no non-hyperbolic singularity.

Integrated Applications of Microalgae to Wastewater Treatment and Biorefinery: Recent Advances and Opportunities

  • Nguyen, Van Tuyen;Limjuco, Lawrence A.;Lee, Kisay;Dang, Nhat Minh
    • Applied Chemistry for Engineering
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    • v.33 no.3
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    • pp.242-257
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    • 2022
  • Microalgae is becoming a vital component for a circular economy and ultimately for sustainable development. Herein, recent developments in different outcomes of microalgae for wastewater treatment and biorefinery were reviewed. From its primary function as a third-generation resource of biofuel, the usage of microalgae has been diversified as an integral element for the CO2 sequestration and production of economically valuable products (e.g., pharmaceuticals, animal feeds, biofertilizer, biochar, etc.). Principles and recent challenges for each microalgae application were presented to suggest a motivation for future research and the direction of development. The integration of microalgae within the concept of the circular economy was also discussed with various routes of microalgae-based biorefinery.

General Local Transformer Network in Weakly-supervised Point Cloud Analysis (약간 감독되는 포인트 클라우드 분석에서 일반 로컬 트랜스포머 네트워크)

  • Anh-Thuan Tran;Tae Ho Lee;Hoanh-Su Le;Philjoo Choi;Suk-Hwan Lee;Ki-Ryong Kwon
    • Annual Conference of KIPS
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    • 2023.11a
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    • pp.528-529
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    • 2023
  • Due to vast points and irregular structure, labeling full points in large-scale point clouds is highly tedious and time-consuming. To resolve this issue, we propose a novel point-based transformer network in weakly-supervised semantic segmentation, which only needs 0.1% point annotations. Our network introduces general local features, representing global factors from different neighborhoods based on their order positions. Then, we share query point weights to local features through point attention to reinforce impacts, which are essential in determining sparse point labels. Geometric encoding is introduced to balance query point impact and remind point position during training. As a result, one point in specific local areas can obtain global features from corresponding ones in other neighborhoods and reinforce from its query points. Experimental results on benchmark large-scale point clouds demonstrate our proposed network's state-of-the-art performance.

Facial Manipulation Detection with Transformer-based Discriminative Features Learning Vision (트랜스포머 기반 판별 특징 학습 비전을 통한 얼굴 조작 감지)

  • Van-Nhan Tran;Minsu Kim;Philjoo Choi;Suk-Hwan Lee;Hoanh-Su Le;Ki-Ryong Kwon
    • Annual Conference of KIPS
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    • 2023.11a
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    • pp.540-542
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    • 2023
  • Due to the serious issues posed by facial manipulation technologies, many researchers are becoming increasingly interested in the identification of face forgeries. The majority of existing face forgery detection methods leverage powerful data adaptation ability of neural network to derive distinguishing traits. These deep learning-based detection methods frequently treat the detection of fake faces as a binary classification problem and employ softmax loss to track CNN network training. However, acquired traits observed by softmax loss are insufficient for discriminating. To get over these limitations, in this study, we introduce a novel discriminative feature learning based on Vision Transformer architecture. Additionally, a separation-center loss is created to simply compress intra-class variation of original faces while enhancing inter-class differences in the embedding space.

Continuous Behavior of Using Food Delivery Mobile Applications in Vietnam after Covid-19 Pandemic

  • Ha Thu, LUONG;Nhi Lan, DAO;Trang Thu, NGUYEN;Uyen Thu Thi, LA;Na Thi Le, TRAN;Hoa Thi, DUONG
    • Journal of Distribution Science
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    • v.21 no.3
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    • pp.47-60
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    • 2023
  • Purpose: During and after Covid-19 pandemic, technology has emerged as a key factor in supporting the recovery of the economy and the rise of living standards. This study examines seven factors affecting the intention of food delivery apps usage, which include Performance Expectancy, Effort Expectancy, Social Influence, Hedonic Motivation, Price Value, and Habit, and how much influence they have on the customers' behavioral continuance of food delivery apps after Covid-19 Pandemic. Research methodology: This research is a quantitative descriptive research with 473 qualified respondents from 550 respondents collected. Besides using the UTAUT2 model (Venkatesh et al., 2012), Information Quality was added to give a better explanation for the consumers' intention towards continuance behavior using food delivery apps. The collected data is then processed using SPSS 22.0. Results: Habit factors and Information Quality factors have significant positive effects on promoting food delivery apps usage intention, which in turn influences continuance behavior. In addition, Habit factors and Information Quality factors together have an effect of 48.57% on Behavioral Intention. Conclusion: The result proves that positive habits and food information quality can increase the usage intention towards the behavioral continuance of consumers. Higher usage frequency can be improved by increasing these two factors.

Facile synthesis of ZnBi2O4-graphite composites as highly active visible-light photocatalyst for the mineralization of rhodamine B

  • Nguyen, Thi Mai Tho;Bui, The Huy;Dang, Nguyen Nha Khanh;Ho, Nguyen Nhat Ha;Vu, Quang Huy;Ngo, Thi Tuong Vy;Do, Manh Huy;Duong, Phuoc Dat;Nguyen, Thi Kim Phuong
    • Korean Journal of Chemical Engineering
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    • v.35 no.12
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    • pp.2442-2451
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    • 2018
  • Novel highly active visible-light photocatalysts in the form of zinc bismuth oxide ($ZnBi_2O_4$) and graphite hybrid composites were prepared by coupling via a co-precipitation method followed by calcination at $450^{\circ}C$. The asprepared $ZnBi_2O_4$-graphite hybrid composites were tested for the degradation of rhodamine B (RhB) solutions under visible-light irradiation. The existence of strong electronic coupling between the two components within the $ZnBi_2O_4$-graphite heterostructure suppressed the photogenerated recombination of electrons and holes to a remarkable extent. The prepared composite exhibited excellent photocatalytic activity, leading to more than 93% of RhB degradation at an initial concentration of $50mg{\cdot}L^{-1}$ with 1.0 g catalyst per liter in 150 min. The excellent visible-light photocatalytic mineralization of $ZnBi_2O_4-1.0graphite$ in comparison with pristine $ZnBi_2O_4$ could be attributed to synergetic effects, charge transfer between $ZnBi_2O_4$ and graphite, and the separation efficiency of the photogenerated electrons and holes. The photo-induced $h^+$ and the superoxide anion were the major active species responsible for the photodegradation process. The results demonstrate the feasibility of $ZnBi_2O_4-1.0graphite$ as a potential heterogeneous photocatalyst for environmental remediation.

The Report on the Medical Voluntary Activities for Cleft Lip and Palate in Vietnam by the Korean Association of Maxillofacial Plastic and Reconstructive Surgeons (대한악안면성형재건외과학회(KAMPRS)의 베트남 구순구개열 무료 의료 봉사 활동에 관한 보고)

  • Hahm, Tae-Hoon;Shin, Hyo-Keun;Kim, Jong-Ryul;Ryu, Dong-Mok;Ryu, Sun-Youl;Kim, Kyoung-Won;Park, Young-Wook;Jung, Young-Soo
    • Korean Journal of Cleft Lip And Palate
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    • v.13 no.1
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    • pp.23-28
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    • 2010
  • 대한악안면성형재건외과학회는 2004년도부터 매년 인도적 차원에서 의료 환경이 낙후된 Vietnam의 cleft lip and palate 환자들을 치료하기 위해 무료로 해외 진료 봉사 활동을 해왔다. 초창기 해외 진료 봉사 활동 당시 베트남 의료 기술 발달이 미비하여 준비해야 할 것들이 많았으나 이 후 베트남의 경제 발전과 함께 의료 시설 및 의료 기술이 발달함에 따라 준비 품목 등이 간단명료해지고 현지 지원 및 수술 준비도 원활히 진행되었다. 이러한 무료 의료 봉사 활동을 계기로 개발도상국의 낙후된 의료 시설 및 의료 기술 발전, 의료 혜택을 받지 못한 구순 구개열 환자의 정상적 안모 및 기능 회복, 조건 없는 의료 봉사 활동을 통한 민간외교 효과 및 양국간의 우호 증진 등의 성과가 있었다. 대한악안면성형재건외과학회에서는 2009년도 역시 베트남 National Institute of Odonto-stomatology 에서 11월17일부터 26일까지 cleft lip and palate 무료수술진료단(단장 신효근)을 보내 수술봉사 활동을 펼치고 돌아 왔다. 일반적인 구순구개열 뿐만 아니라 양측성 안면열(Bilateral Facial Cleft), 사경(Torticollis) 등의 희귀 기형을 포함하여 수술을 진행하였으며 총 31례의 수술을 성공적으로 마쳤으며 지난 6년 동안의 성과와 함께 이에 대한 보고를 하고자 한다.

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