Surface plasmon-assisted optical switching/bistability at telecommunication wavelengths in nonlinear dielectric gratings

Thu Trang Hoang,Khai Q. Le,Quang Minh Ngo 한국물리학회 2015 Current Applied Physics Vol.15 No.9

In this paper, we numerically investigate nonlinear optical responses in dielectric gratings coated by flat metallic surface, where the structural parameters are chosen for wavelengths of operation at the telecom regime. The presented designs show the output light reflection with respect to the incident intensity of increasing, decreasing, and non-monotonic belt-shape functions. Nonlinear optical responses including switching and bistability appeared in the telecom region owing to assistance of surface plasmon resonance excited at the metal/dielectric interface, which enhances the diffraction efficiency and induces the momentum matching for the leaky modes of the dielectric grating. This results in electric intensityeffective refractive index dependence enhancement in the Kerr nonlinear media. Our design and investigation of the linear and nonlinear optical responses will provide a general guideline for a hybrid metallic-dielectric structure-based optical switching/bistability device design.

Biomedical and Environmental Applications of Chitosan-based Nanomaterials

( Jae Kweon Park ),( Lam Dai Tran ),( Hoang Vinh Tran ),( Trang Thu Mai ),( Thu Phuong Ha ),( Binh Hai Nguyen ),( Hoang Thai ),( Hoang Dinh Vu ),( Dien Gia Pham ),( Phuc Xuan Nguyen ) 한국키틴키토산학회 2011 한국키틴키토산학회지 Vol.16 No.1

Being naturally abundant resources and having many interesting physicochemical and biological properties, chitin/chitosan have been found useful in many fields. This paper describes the strategy to design a multifunctional, chitosan based nanomaterials and their biomedical and environmental applications. Different physicochemical methods including FESEM/TEM, PPMS were used to characterize the obtained nanomaterials. For each application, a series of specific characterizing methods were used for evaluating the applicability/capacity of materials.

Cardiovascular Imaging Development in Vietnam

Hoang Minh Loi,Nguyen Thi Thu Hoai,Nguyen Ngoc Trang 아시아심장혈관영상의학회 2022 Cardiovascular Imaging Asia Vol.6 No.2

Together with the 60 years of development of Vietnamese Society of Radiology and Nuclear Medicine, cardiovascular imaging also has some remarkable points in echocardiography, cardiac CT, cardiac MRI. In 2021 remarks an important moment, the 14th Asian Society of Cardiovascular Imaging Congress was successfully organized for the first time in Vietnam through an online platform.

Nominal Price Anomaly in Emerging Markets: Risk or Mispricing?

HOANG, Lai Trung,PHAN, Trang Thu,TA, Linh Nhat Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.9

This study examines the nominal price anomaly in the Vietnamese stock market, that is, whether stocks with low nominal price outperform stocks with high nominal price. Using a sample of all 351 companies listed on the Ho Chi Minh Stock Exchange (HOSE) from June 2009 to March 2018, we confirm our hypothesis and document that cheaper stocks yield higher subsequent abnormal returns. The results are robust after controlling for various stock characteristics that have been documented to be value-relevant in prior literature, including firm size, book-to-market ratio, intermediate-term momentum, short-term reversal, skewness, market risk, idiosyncratic risk, illiquidity and extreme daily returns, using both the portfolio analysis and the Fama-MacBeth cross-sectional regression. The negative effect persists in the long term (i.e., after up to 12 months), implying a slow adjustment of stock prices to their intrinsic value. Further analysis show that the observed nominal price anomaly is mainly driven by mispricing but not a latent risk factor proxied by stock price, thus the observed anomaly reflects a mispricing but not a fundamental risk. The study highlights the irrational behaviour of investors and market inefficiency in the Vietnamese stock market and provides important implication for investors in the market.

What Makes Vietnamese (Not) Attend Periodic General Health Examinations? A 2016 Cross-sectional Study

Quan-Hoang Vuong,Quang-Hoi Vu,Thu-Trang Vuong 질병관리본부 2017 Osong Public Health and Research Persptectives Vol.8 No.2

Objectives: General health examinations (GHE) have become an increasingly common measure for preventive medicine in Vietnam. However, little is known about the factors among Vietnamese people who attend or miss GHE. Budget or time constraints remain to be evaluated for better-informed policy making. This study investigates factors affecting behaviors in attending periodic GHE. The main objectives are as follows: (1) to explore empirical relationships between influencing factors and periodic GHE frequencies, and (2) to predict the probabilities of attending GHE under associated conditions. Methods: The study used a 2,068-observational dataset, obtained from a Vietnamese survey in 2016. The analysis was then performed using the methods of baseline-category logits for establishing relationships between predictor and response variables. Results: Significant relationships were found among the expenditure and time consumption, health priority and sensitivity to health data, insurance status, and frequency of GHE, with most p-values = 0.01. Conclusion: Generally, people attended the GHE when they had the resources and health priorities (72.7% probability). Expenditure and time remain key obstacles to the periodic GHE. Health priority and health data are important in improving rates for GHEs. Health insurance should play a positive role in promoting the GHE.

Effects of Maleic Anhydride Grafted Ethylene/Vinyl Acetate Copolymer (EVA)on the Properties of EVA/Silica Nanocomposites

Thai Hoang,Nguyen Thuy Chinh,Nguyen Thi Thu Trang,To Thi Xuan Hang,Dinh Thi Mai Thanh,Dang Viet Hung,하창식,Maëlenn Aufray 한국고분자학회 2013 Macromolecular Research Vol.21 No.11

Ternary nanocomposites based on ethylene/vinyl acetate copolymer (EVA), maleic anhydride-grafted EVA (EVAgMA), and nanosilica were prepared in a Haake Rheomixer. The structure of the EVA/EVAgMA/silica nanocomposites was characterized by Fourier transform infrared spectroscopy and field emission scanning electron microscopy. The blending sequence was found to have a significant effect on the microstructure of EVA/EVAgMA/silica nanocomposites and the dispersion behavior of the nanosilica in the EVA matrix. The tensile properties (tensile strength and elongation at break), thermal behavior, crystalline structure and weatherability of the nanocomposites were also studied. The results showed that the above properties of the nanocomposites were enhanced remarkably using 1 wt% EVAgMA.

Characteristics of retracted articles based on retraction data from online sources through February 2019

Quan-Hoang Vuong,Viet-Phuong La,Manh-Tung Ho,Thu-Trang Vuong,Manh-Toan Ho 한국과학학술지편집인협의회 2020 Science Editing Vol.7 No.1

Purpose: Although retractions are commonly considered to be negative, the fact remains that they play a positive role in the academic community. For instance, retractions help scientific enterprise perform its self-correcting function and provide lessons for future researchers; furthermore, they represent the fulfillment of social responsibilities, and they enable scientific communities to offer better monitoring services to keep problematic studies in check. This study aims to provide a thorough overview of the practice of retraction in scientific publishing from the first incident to the present. Methods: We built a database using SQL Server 2016 and homemade artificial intelligence tools to extract and classify data sources including RetractionWatch, official publishers’ archives, and online communities into ready-to-analyze groups and to scan them for new data. After data cleaning, a dataset of 18,603 retractions from 1,753 (when the first retracted paper was published) to February 2019, covering 127 research fields, was established. Results: Notable retraction events include the rise in retracted articles starting in 1999 and the unusual number of retractions in 2010. The Institute of Electrical and Electronics Engineers, Elsevier, and Springer account for nearly 60% of all retracted papers globally, with Institute of Electrical and Electronics Engineers contributing the most retractions, even though it is not the organization that publishes the most journals. Finally, reasons for retraction are diverse but the most common is “fake peer review”. Conclusion: This study suggests that the frequency of retraction has boomed in the past 20 years, and it underscores the importance of understanding and learning from the practice of retracting scientific articles.

Factors Affecting the Adoption of IFRS: The Case of Listed Companies on Ho Chi Minh Stock Exchange

TA, Trang Thu,PHAM, Cuong Duc,NGUYEN, Anh Huu,DOAN, Nga Thanh,DINH, Hang Thuy,DO, Giang Hoang,PHAM, Truong Hong Korea Distribution Science Association 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.2

The study investigates the key factors that affect the adoption of the International Financial Reporting Standards (IFRS) by companies listed on Ho Chi Minh Stock Exchange (HOSE) in Vietnam. The factors that are studied in this research include total debt-to-equity ratio, firm size, return-on-equity ratio, audit quality, foreign investment, and financial institution category. The authors have utilized quantitative and qualitative analyses in combination with a logistics regression model and other available analytical tools for conducting the research. All statistics processed in the paper were based on 379 audited financial statements issued in 2018. The results reveal that factors like firm size, return on equity (ROE), audit quality, foreign investment, and financial institution category positively affect the IFRS adoption of HOSE-listed companies, while total debt-to-equity ratio negatively impacts the adoption. The findings suggest Vietnamese law and policy-makers, when promoting the adoption of IFRS by listed companies, should focus more on five variables with positive influence and they can disregard the total debt-to-equity ratio that is insignificant as a factor affecting the adoption of IFRS. This implication could be applied for other firms in Vietnam and for enterprises in other countries, which are in the same stage of IFRS application.

Sharing Economy: Generation Z's Intention Toward Online Fashion Rental in Vietnam

PHAM, Huong Trang,HOANG, Kim Thu,NGUYEN, Thi Thoa,DO, Phuong Huyen,MAR, Ma Tin Cho Korea Distribution Science Association 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.3

The last decade has seen the emergence of the idea of "sharing economy" as people are more aware of environmental issues. Although clothing businesses applying the model of sharing consumption have emerged recently, less research effort has been invested in this topic, especially in investigating young consumers' intention. The purpose of this study is to investigate factors driving Generation Z consumers' behavioral intention toward online fashion rental. In this research, a conceptual framework is proposed based on the Theory of Planned Behavior and Technology Acceptance Model. To test the research model and hypotheses, a survey of 375 students and pupils was conducted in Vietnam. All the scales' reliability and validity were assessed through Cronbach's Alpha and confirmatory factor analysis. Structural equation modeling was used to assess the relationship among constructs. The study results showed that attitude toward behavior, subjective norm and perceived behavioral control were positive contributors to Gen Z's intention to use online fashion rental. Besides, the positive relationships between attitude and two other factors - perceived usefulness and perceived ease of use - were also highlighted. Moreover, the findings provided empirical evidence for supporting the positive impact of interpersonal influence, e-WOM, and influencer e-marketing on subjective norm.

Mott Transition in the Asymmetric Hubbard Model at Half-filling: Equation of Motion Approach

Anh-Tuan Hoang,Thi-Thu-Trang Tran,Duc-Anh Le 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.68 No.2

We investigate the Mott metal-insulator transition in the asymmetric Hubbard model, which may describe the ground states of fermionic atoms trapped in optical lattices. We use the dynamical mean-field theory and the equation of motion approach to calculate the density of states at the Fermi level and the double occupation for various values of the on-site interaction U and the hopping asymmetry r. The critical interaction is also obtained as a function of the hopping asymmetry. Our results are in good agreement with the ones obtained by using the dynamical mean field theory with the exact diagonalization and the quantum Monte Carlo techniques.