Factors Affecting Corporate Investment Decision: Evidence from Vietnamese Economic Groups

Duong Thuy PHAN,Ha Thi NGUYEN 한국유통과학회 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.11

This paper analyzes factors affecting corporate investment decisions in economic groups listed on the Vietnam stock market. The panel data of the research sample includes 39 economic groups listed on the Vietnam stock market from 2009 to 2019. The Generalized Least Square (GLS) is employed to address econometric issues and to improve the accuracy of the regression coefficients. In this research, the investment rate is a dependent variable. Cash-flow (CF), Investment opportunities (ROA), Fixed capital intensity (FCI), Leverage (LEV), Sales growth (GR), Size (SZ), Business risk (RISK) are independent variables in the study. The model results show that cash flow and sales growth have the same impact on investment decisions of economic groups in Vietnam. In addition, investment opportunities have a negative impact on the capital investment decisions of economic groups. The remaining factors include fixed capital intensity, leverage, firm size, and business risks that have a weak and insignificant impact on capital investment decisions of economic groups in Vietnam. The findings of this article are useful for business administrators, and helping business managers make the right financial decisions. Besides, the research results are also meaningful to money management agencies. The authors recommend that the State Bank of Vietnam should maintain a sustainable monetary policy.

Morphological effect of TiO2 catalysts on photocatalytic degradation of methylene blue

Thuy-Duong Nguyen-Phan,Eun Woo Shin 한국공업화학회 2011 Journal of Industrial and Engineering Chemistry Vol.17 No.3

In our previous study, we reported a simple hydrothermal preparation of TiO_2 materials using concentrated hydrochloric acid and controlled the morphology of TiO2 by changing the hydrochloric acid amounts. In this study, we employed the TiO_2 materials with different morphologies in the photocatalytic degradation of methylene blue. In the photocatalytic results, the TiO_2 particles with the prisms and flower-like morphology (DTC-5.0) exhibited the highest photocatalytic activity with kapp = 12.33 × 10^3 min1 due to the synergetic effect of morphology and mixed-phase crystal of TiO_2.

Surfactant removal from mesoporous TiO2 nanocrystals by supercritical CO2 fluid extraction

Thuy-Duong Nguyen-Phan,Hai-Dinh Pham,Sunwook Kim,Eun-Seok Oh,Eui Jung Kim,Eun Woo Shin 한국공업화학회 2010 Journal of Industrial and Engineering Chemistry Vol.16 No.5

In this study, mesoporous TiO2 crystals were synthesized with a sol–gel process in the presence of hexadecylamine which was used as a structure-directing agent. The neutral template was removed by either supercritical CO2 extraction (SCE) or conventional calcinations to produce mesopores, and the pore characteristics of mesoporous TiO2 were investigated with TGA, XRD, FT-IR, SEM and N2 sorption analysis. The results showed that hexadecylamine was completely combusted by a thermal treatment above 400 8C, whereas SCE successfully removed more than 62% of the surfactant with methanol used as a modifier. However, in contrast to SCE, calcination at 400 8C accompanied a reduction in surface area and pore volume, as well as the partial collapse of the mesostructure. The combination of SCE and subsequent heat treatment at 400 8C not only improved the porosity but also retarded the structure destruction due to much less exothermal behavior. The SCE approach provided mesoporous TiO2nanocrystals with remarkably highmesoporosity. The SCE technique can result in numerous advantages such as high mesoporosity, short processing time, low energy consumption, and environmental benefit. 2010 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Influence of heat treatment on thermally-reduced graphene oxide/TiO2 composites for photocatalytic applications

Thuy-Duong Nguyen-Phan,Viet Hung Pham,Hyunran Yun,김의정,Seung Hyun Hur,정진석,신은우 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.12

Thermally-reduced graphene oxide/TiO2 composites (TRGO/Ti) were prepared by the thermal reduction of graphene oxide/TiO2 composite that was obtained from a simple, environmentally friendly, one-step colloidal blending method. The changes in structural and textural properties as well as their corresponding photocatalytic activities were investigated as a function of calcination temperature. The presence of stacked TRGO sheets significantly retarded both the aggregation and the crystalline phase transformation of TiO2 as increasing the temperature from 200 to 600 oC. TRGO/Ti composites exhibited higher photocatalytic activity for the degradation of methylene blue in comparison with pure TiO2 due to the increase in specific surface area and the formation of π-π conjugations between dye compounds and aromatic regions of TRGO. However, increasing the calcination temperature resulted in the lower photoactivity and slower kinetics, which can be ascribed to the decrease in surface area, the reduction of oxygen vacancies, and the loss of functional groups at the edges or on the basal planes of the TRGO sheets.

Factors Affecting Debt Maturity Structure: Evidence from Listed Enterprises in Vietnam

PHAN, Duong Thuy Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.10

This paper analyzes factors affecting the debt maturity structure of enterprises listed on the Vietnam stock market. The panel data of research sample includes 549 non-financial listed enterprises on the Vietnam stock market from 2009 to 2019. The Generalized Least Square (GLS) tool is employed to address econometric issues and to improve the accuracy of the regression coefficients. In this research, debt maturity structure is the dependent variable. Capital structures, fixed assets, liquidity, firm size, asset maturity, profitability, corporate income tax, gross domestic product, inflation rate, credit growth scale are independent variables in the study. The model results show, that among the factors affecting the structure of debt maturity, the capital structure, asset structure, and firm size have the highest estimation coefficients, which shows that capital structure, asset structure, and firm size plays an important role in the decision-making process of debt maturity structure. The empirical results show that there are differences in the impact of these factors on the debt maturity structures in state-owned enterprises and non-state enterprises listed on the Vietnam stock market. The findings of this article are useful for business administrators, helping business managers make the right financial decisions to determine the target debt maturity structure in enterprises.

Morphological evolution of hierarchical nickel titanates by elevation of the solvothermal temperature

Nguyen-Phan, Thuy-Duong,Nguyen-Huy, Chinh,Woo Shin, Eun Elsevier 2014 Materials letters Vol.131 No.-

<P><B>Abstract</B></P> <P>In this study, the morphological evolution of hierarchical nickel titanates was first-ever investigated by simply raising the solvothermal temperature. At room temperature, irregular aggregates of anatase TiO<SUB>2</SUB> nanoparticles were reluctantly formed. Increasing the temperature to 100°C resulted in the assembly of 3D drum-shaped nickel titanate clusters where the three-dimensional geometry was constructed via coalescent nanoparticles with a mean size of 126.8nm. An intermediate stage containing circular cylinders and irregular prisms was obtained at intermediate temperatures. Further elevation of the solvothermal temperature to 160°C and 180°C gave 1D uniform hexagonal nanoprisms of nickel titanates. Increasing the solvothermal temperature accelerates the nucleation rate, which drastically promotes crystallization and self-assembly, thereby evolving to the hierarchical structure of NiTiO<SUB>3</SUB>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Morphological evolution of NiTiO<SUB>3</SUB> was investigated by solvothermal temperatures. </LI> <LI> At room temperature, irregular aggregates of anatase TiO<SUB>2</SUB> nanoparticles were formed. </LI> <LI> 3D drum-shaped NiTiO<SUB>3</SUB> clusters were synthesized via small nanoparticles at 100°C. </LI> <LI> Circular cylinders and irregular prisms of NiTiO<SUB>3</SUB> were obtained at 130°C. </LI> <LI> 1D uniform hexagonal NiTiO<SUB>3</SUB> nanoprisms were constructed at 160°C and 180°C. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Mesoporous titanosilicate/reduced graphene oxide composites: layered structure, high surface-to-volume ratio, doping effect and application in dye removal from water

Nguyen-Phan, Thuy-Duong,Shin, Eun Woo,Pham, Viet Hung,Kweon, Hyukmin,Kim, Sunwook,Kim, Eui Jung,Chung, Jin Suk The Royal Society of Chemistry 2012 Journal of materials chemistry Vol.22 No.38

<P>In this study, a new system of integrated photocatalytic adsorbents (IPCAs), three-dimensional wormhole-like mesoporous titanosilicate/reduced graphene oxide layered composites, were prepared with various Ti/Si ratios. The reduced graphene oxide (RGO) nanosheets played the role of giant two-dimensional (2D) platforms for the deposition, spreading and growth of mesostructured layers, leading to a significant enhancement in mesoporosity. The substitution of titanium species into the mesoporous silica/RGO significantly changed the textural, physicochemical and optical properties. Gradually increasing the Ti doping content dramatically promoted the adsorptivity and UV-photocatalytic degradation of the dye contaminant; however, an excess dosage (20 mol%) inhibited the UV activity. This could be attributed to the changes in the coordination geometry and electronic states of Ti species in the composites. The IPCAs that dominantly contained highly dispersed and isolated Ti-oxide species in tetrahedral coordination within a mesostructured framework exhibited much higher photoactivity than those composed of aggregated and octahedrally coordinated Ti species due to the formation of efficient charge-transfer excited states.</P> <P>Graphic Abstract</P><P>Mesoporous titanosilicate/reduced graphene oxide layered composites exhibited good adsorptivity and photodegradation of a dye contaminant. Highly dispersed and isolated tetrahedral Ti-oxide species in the mesostructured framework were beneficial to photoreactivity. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2jm33309k'> </P>

Logistics Service Quality, Customer Satisfaction, and Loyalty During the COVID-19 Pandemic in Vietnam

Xuan Hung NGUYEN(Xuan Hung NGUYEN ),Thuy Dương TRAN(Thuy Dương TRAN ),Phan Hoai Diem VU(Phan Hoai Diem VU ),Yen Chi DINH(Yen Chi DINH ),Thi Mai Huong DUONG(Thi Mai Huong DUONG ),Thi Ngoc Hien THAN(Thi 한국유통과학회 2022 The Journal of Asian Finance, Economics and Busine Vol.9 No.9

The goal of the study is to examine and assess how the factors of logistics service quality provided by logistics service providers influence customer loyalty and satisfaction in Vietnam. This study employs samples of the Kansei technique. The article’s data was gathered through an online survey of 388 distinct Vietnamese customers who used logistics services before and during the Covid-19 outbreak. After the data was obtained, it was evaluated using SmartPLS 3.0’s Cronbach’s Alpha test and structural equation model (SEM). Staff service quality, operational service quality, and technical service quality are the three factors that determine the quality of logistics services in the study. Out of the 10 proposed hypotheses, research findings show that five are acceptable. The Covid-19 Pandemic in Vietnam had a significant impact on all dimensions, but it had no effect on how satisfied customers were with the logistics service providers. Nevertheless, loyalty is considerably influenced by only one factor, which is customer satisfaction, and customer trust moderates the relationship between these two factors. As a consequence of that, several managerial implications have been proposed to help logistics service providers improve their services to attract and keep Vietnamese customers using their service in the long term.

Synthesis and Characterization of Hydrotalcite/Graphene Oxide Containing Benzoate for Corrosion Protection of Carbon Steel

( Thuy Duong Nguyen ),( Boi An Tran ),( Ke Oanh Vu ),( Anh Son Nguyen ),( Anh Truc Trinh ),( Gia Vu Pham ),( Thi Xuan Hang To ),( Thanh Thao Phan ) 한국부식방식학회(구 한국부식학회) 2020 Corrosion Science and Technology Vol.19 No.2

This work examined the corrosion protection performance of benzoate loaded hydrotalcite/graphene oxide (HT/GO-BZ) for carbon steel. HT/GO-BZ was fabricated by the co-precipitation method and characterized by infrared spectroscopy, X-ray diffraction, and scanning electronic microscopy. The corrosion inhibition action of HT/GO-BZ on carbon steel in 0.1 M NaCl solution was evaluated by electrochemical measurements. The benzoate content in HT/GO-BZ was determined by UV-Vis spectroscopy. Subsequently, the effect of HT/GO-BZ on the corrosion resistance of the water-based epoxy coating was investigated by the salt spray test. The obtained results demonstrated the intercalation of benzoate and GO in the hydrotalcite structure. The benzoate content in HT/GO-BZ was about 16%. The polarization curves of the carbon steel electrode revealed anodic corrosion inhibition activity of HT/GO-BZ and the inhibition efficiency was about 95.2% at a concentration of 3g/L. The GO present in HT/GO-BZ enhanced the inhibition effect of HT-BZ. The presence of HT/GO-BZ improved the corrosion resistance of the waterborne epoxy coating.

Smart vaccine delivery based on microneedle arrays decorated with ultra-pH-responsive copolymers for cancer immunotherapy

Duong, Huu Thuy Trang,Yin, Yue,Thambi, Thavasyappan,Nguyen, Thanh Loc,Giang Phan, V.H.,Lee, Min Sang,Lee, Jung Eun,Kim, Jaeyun,Jeong, Ji Hoon,Lee, Doo Sung Elsevier 2018 Biomaterials Vol.185 No.-

<P><B>Abstract</B></P> <P>Despite the tremendous potential of DNA-based cancer vaccines, their efficacious delivery to antigen presenting cells to stimulate both humoral and cellular response remains a major challenge. Although electroporation-based transfection has improved performance, an optimal strategy for safe and pain-free vaccination technique remains elusive. Herein, we report a smart DNA vaccine delivery system in which nanoengineered DNA vaccine was laden on microneedles (MNs) assembled with layer-by-layer coating of ultra-pH-responsive OSM-(PEG-PAEU) and immunostimulatory adjuvant poly(I:C), a synthetic double stranded RNA. Transcutaneous application of MN patches onto the mice skin perforate the stratum corneum with minimal cell damage; subsequent disassembly at the immune-cell-rich epidermis/dermis allows the release of adjuvants and DNA vaccines, owing to the ultra-sharp pH-responsive nature of OSM-(PEG-PAEU). The released adjuvant and DNA vaccine can enhance dendritic cell maturation and induce type I interferons, and thereby produce antigen-specific antibody that can achieve the antibody-dependent cell-mediated cytotoxicity (ADCC) and CD8<SUP>+</SUP> T cell to kill cancer cells. Strikingly, transcutaneous application of smart vaccine formulation in mice elicited 3-fold greater frequencies of Anti-OVA IgG1 serum antibody and 3-fold excess of cytotoxic CD8<SUP>+</SUP> T cell than soluble DNA vaccine formulation. As a consequence, the formulation rejected the murine B16/OVA melanoma tumors in C57BL/6 mice through the synergistic activation of antigen-specific ADCC and cytotoxic CD8<SUP>+</SUP> T cells. The maneuvered use of vaccine and adjuvant poly(I:C) in MNs induces humoral and cellular immunity, which provides a promising vaccine technology that shows improved efficacy, compliance, and safety.</P>