Transparent Field-Emission Device Based on a Puried SWNT and Spin-on-Glass Composite

Nguyen Van Quy,Nguyen Duc Hoa,조유석,Myunchan An,송혜진,Youngjin Kang,김도진 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.5

A fabrication process for a transparent field-emission device based on a composite of spin-on- glass (SOG) and single-walled carbon nanotubes (SWNTs) is developed. The highly crystalline single-walled carbon nanotubes were synthesized by using an arc discharge method. Amorphous carbon and metallic materials were removed by purification using thermal and chemical treatments to enhance the transparency of the emitter. A SOG-SWNT composite was then formed by spin- coating the SOG on the puried SWNTs. The field-emission device based on the SOG-SWNT composite exhibited a high current density of 4 mAcm-2 and a low turn-on field emission of 1.6 Vμm-1. A very high eld enhancement factor of 2.5×106 cm2 demonstrated the high performance of the transparent field-emission device. The emitter device was mechanically stable in its role as an adhesion medium, SOG. A fabrication process for a transparent field-emission device based on a composite of spin-on- glass (SOG) and single-walled carbon nanotubes (SWNTs) is developed. The highly crystalline single-walled carbon nanotubes were synthesized by using an arc discharge method. Amorphous carbon and metallic materials were removed by purification using thermal and chemical treatments to enhance the transparency of the emitter. A SOG-SWNT composite was then formed by spin- coating the SOG on the puried SWNTs. The field-emission device based on the SOG-SWNT composite exhibited a high current density of 4 mAcm-2 and a low turn-on field emission of 1.6 Vμm-1. A very high eld enhancement factor of 2.5×106 cm2 demonstrated the high performance of the transparent field-emission device. The emitter device was mechanically stable in its role as an adhesion medium, SOG.

Precipitation-Mediated PEGylation of Plant-Derived Nanovesicles

Van Quy Nguyen,엄우람,안재윤,주혜연,최영찬,정재민,최지석,유동길,조용우,박재형 한국고분자학회 2022 Macromolecular Research Vol.30 No.2

Recently, plant-derived nanovesicles have attracted interest in the field of regenerative medicine because of their abundant immune-regulatory RNAs and phytochemicals with cell proliferation activity. However, the poor stability and rapid clearance of vesicles remain major challenges in their clinical applications. Herein, we report a facile method for surface modification of plant-derived nanovesicles by precipitation in the presence of poly(ethylene glycol) (PEG). We confirmed that PEGylation of nanovesicles slightly increased the particle size and zeta potential values. Importantly, this simple precipitation method produced PEGylated nanovesicles without any quantitative or qualitative loss of internal contents. When dispersed in PBS (pH 7.4), PEGylated nanovesicles did not exhibit a significant change in size for 24 h, indicating their high stability. Overall, our precipitation-based method is a useful technique for PEGylation of plant-derived nanovesicles without loss of bioactivity.

Novel synthesis of highly ordered mesoporous Fe2O3/SiO2nanocomposites for a room temperature VOC sensor

Nguyen Van Quy,Tran Minh Hung,Trinh Quang Thong,Le Anh Tuan,Tran Quang Huy,Nguyen Duc Hoa 한국물리학회 2013 Current Applied Physics Vol.13 No.8

The controlled synthesis of mesoporous silica and metal oxide nanocomposites with a highly ordered porous structure and large specific surface area for specific applications has been an attractive topic in the field of porous materials. Herein, we introduce a novel method for the fabrication of highly ordered mesoporous structured and large specific surface area Fe2O3/SiO2 nanocomposites, and consider their application in room temperature gas sensors. The mesoporous Fe2O3/SiO2 nanocomposites were synthesised by a two-step method, which combines the hydrothermal growth of Fe2O3 nanoparticles and the microemulsion phase of Brij 56 (C16EO10) surfactant as templates in instantly direct-templating synthesis. This synthesis method enables the fabrication of mesoporous Fe2O3/SiO2 nanocomposites without distortion of the ordered porous structure after calcination at high temperature. The synthesised materials were found to be efficient in a room temperature VOC sensor application, with good recovery.

Diselenide-Bearing Liposomes for Intracellular Delivery of a Vitamin C Derivative in Cancer Cells

Van Quy Nguyen,유동길,오병훈,Van Dat Bui,안재윤,엄우람,박재형 한국고분자학회 2021 Macromolecular Research Vol.29 No.5

Vitamin C, which promotes oxidative stress, has emerged as an alternative to conventional chemotherapy for treating cancers. However, owing to its cytotoxicity, vitamin C should be delivered to cells in its oxidized form, dehydroascorbate (DHA). Glutathione (GSH)-responsive nanoparticles (G-NPs) have been prepared as potential carriers of DHA by incorporating diselenide-based amphiphilic lipids into the liposomal membrane. Bare liposomes without diselenide-based lipids were prepared as control NPs; these exhibited particle sizes and surface charges comparable to those of G-NPs. DHA was physically encapsulated in NPs using the dehydrationrehydration method. DHA-loaded G-NPs induced much higher GSH depletion in HT29 colon cancer cells than DHA-loaded controls. Interestingly, DHA-loaded G-NPs significantly increased the intracellular levels of reactive oxygen species, implying enhanced oxidative stress by stimuli-responsive DHA release. Consequently, DHA-loaded G-NPs exhibited significant cytotoxicity against HT29 colon cancer cells. Overall, G-NPs might serve as potential carriers for intracellular delivery of DHA during cancer treatment.

A high-performance triode-type carbon nanotube field emitter for mass production

Quy, Nguyen Van,Hoa, Nguyen Duc,An, Myungchan,Cho, Yousuk,Kim, Dojin IOP Pub 2007 Nanotechnology Vol.18 No.34

<P>A triode-type field emission device based on carbon nanotubes (CNTs) synthesized on an anodic aluminum oxide (AAO) template was fabricated. For the improvement of device performance, in addition to the basic advantages of using AAO to obtain uniform CNTs with strong adhesion, several considerations were taken into account, including highly crystalline CNTs synthesized through thermal chemical vapor deposition (CVD) at 1200 °C, lowering the contact resistance with a Ti buffer layer and reducing the pixel size and gate-to-emitter distance. The triode-type field emitter showed a high current density of 20 mA cm<SUP>−2</SUP> and a low turn-on voltage of 16 V. The very high field enhancement factor of 1.6 × 10<SUP>6</SUP> cm<SUP>−1</SUP> confirmed the high efficiency of the triode structure in electron extraction.</P>

MXene/single-walled carbon nanotubes/polymer composite-based wearable heaters with electromagnetic interference shielding performance

Dat Quy Nguyen,Yoonsik Yi,Bok Ki Min,Tam Van Nguyen,Choon-Gi Choi 한국진공학회 2020 한국진공학회 학술발표회초록집 Vol.2020 No.2

Impacts of Foreign Direct Investment on Human Capital in ASEAN

Hoi Van NGUYEN,Thuy Thi Thu NGUYEN,Tha Hien TO,Duong Quy DANG,Trang Thi Dai Luong 한국유통과학회 2020 유통과학연구 Vol.18 No.9

Purpose: Research and development of human capital in countries bring sustainable development to the nations. Especially for developing countries, the attraction of foreign direct investment not only brings economic growth to the country but also contributes to improving human capital. This study aims to assess the impact of foreign direct investment on human capital in ASEAN countries. Research design, data and methodology: With data collected from ASEAN countries from 1990 to 2019, panel data analysis is performed with revised model types (the Pooled OLS, Fixed effect model, Random effect model and regression with Driscoll-Kraay standard errors). Result: The results of the regression analysis show that FDI has a positive impact on human capital. At the same time, the study also found that public investment in education also positively affects human capital; the life expectancy factor does not affect human capital. Conclusions: With this research result, the authors also proposed a number of solutions to improve human capital by attracting FDI and improving the efficiency of investment for the education of ASEAN countries. Besides, public expenditure on education also plays an important role in raising human capital. Therefore, investment in education should be promoted further in the future.

An Analysis of the Meaning Enshrined in the Architecture of the Tay Ninh Holy See of Cao Dai

NGUYEN, Phuoc Tai,DINH, Van Thuy,NGUYEN, Thuan Quy,TRAN THI, Kim Hoang DAOS(The Daesoon Academy of Sciences) 2022 Journal of Daesoon Thought and the Religions of Ea Vol.2 No.1

In the 1920s, a new religion emerged in Tay Ninh Province, Southern Vietnam, under the name Caodaism; also known as the Third Universal Salvation of the Great Dao. It is the result of the typical combination of three main religions (Buddhism, Daoism, and Confucianism). Different ethnic groups populated Tay Ninh, such as Chinese, Khmer, Cham, and Kinh. Additionally, the core principle of Caodaism is known as The Three Religions Returned to the Origin, and it is also expanded as The Five Branches Reunited. The Five Branches are humankind's five ways of self-cultivation: the Way of Humans, the Way of Deities, the Way of Saints, the Way of Immortals, and the Way of Buddhas. Although Caodaism was only founded in 1920, this religion is well known domestically and internationally. This is because Caodaism has a distinctive identity; it is a new religion that advocates a syncretistic combination of essential religious teachings that follow the harmonization and reconciliation between the East and West as well as between the past and present. Moreover, the Tay Ninh Holy See is the most important, first, and largest Cao Dai temple in Vietnam. The temple is located in Tay Ninh Province in southwestern Vietnam. This article aims to introduce the Tay Ninh Holy See as the birthplace of Caodaism and as the largest Cao Dai religious palace, not only in Vietnam but also in other countries that practice Caodaism. A brief overview of Tay Ninh Holy See's origin, history, and planning will be provided. Most importantly, the style of the architecture at the Tay Ninh Holy See will be comprehensively analyzed to shed more light on the meaning of each section and the details of this temple structure.

One-Dimensional Tin-Oxide-Coated Single-Wall Carbon Nanotubes for Gas Sensor Applications

Nguyen Duc Hoa,Nguyen Van Quy,Li Wei,Myungchan An,송혜진,Youngjin Kang,Yousuk Cho,김도진 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.5

We introduce a simple method to synthesize one-dimensional tin-oxide-coated single-wall carbon nanotubes (SWNTs) for gas sensor applications The SWNTs are synthesized directly on a SiO2/Si substrate with comb-type electrodes via the arc-discharge method. Metallic Sn thin layers with various thicknesses are deposited over the grown SWNTs. After that, a rheotaxial and thermal oxidation is performed to spread and convert the tin metal on the surfaces of the SWNTs into tin oxide. The electrical and the NOx gas sensing properties of the sensor devices are then investigated. The as-grown SWNTs sensor exhibited a p-type semiconducting property whereas the tin-oxide- coated SWNTs exhibited an n-type semiconducting property. Moreover, the one-dimensional tin- oxidecoated SWNTs sensor exhibited a higher sensitivity than the pure SWNTs sensor. We introduce a simple method to synthesize one-dimensional tin-oxide-coated single-wall carbon nanotubes (SWNTs) for gas sensor applications The SWNTs are synthesized directly on a SiO2/Si substrate with comb-type electrodes via the arc-discharge method. Metallic Sn thin layers with various thicknesses are deposited over the grown SWNTs. After that, a rheotaxial and thermal oxidation is performed to spread and convert the tin metal on the surfaces of the SWNTs into tin oxide. The electrical and the NOx gas sensing properties of the sensor devices are then investigated. The as-grown SWNTs sensor exhibited a p-type semiconducting property whereas the tin-oxide- coated SWNTs exhibited an n-type semiconducting property. Moreover, the one-dimensional tin- oxidecoated SWNTs sensor exhibited a higher sensitivity than the pure SWNTs sensor.

Influence of Overconfidence and Cash Flow on Investment in Vietnam

NGUYEN, Duy Van,DANG, Duong Quy,PHAM, Giang Hoang,DO, Du Kim Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.2

CEOs Overconfidence can bring potentially risky early decisions to businesses, along with large enterprise free cash flow that can bring different investment decisions with CEOs Overconfidence. Especially in the context of Vietnamese enterprises, CEOs are often influenced by behavioral psychology about overconfidence in investment decisions (due to individual cultural characteristics as well as operating financial markets also depend on many factors outside the market). Therefore, the authors study the impact of overconfidence and cash flow on investment in Vietnamese to find the internal relationship between these three factors in the financial environment in Vietnam. With 480 companies listed on the Vietnam Stock Exchange from 2014 to 2018 (companies have continuous reports), the regression analysis results with panel data (FEM, GLS models, correction of robust and GMM dealing with endogenous problems) have shown Overconfidence has a positive impact on investment. At the same time, the results also indicated that enterprises with overconfident CEOs and large cash flows tend to invest less than enterprises with low cash flow. The results of this study have shown the behavioral behavior of CEOs in Vietnamese enterprises that exist under both prospect theory and effective market theory.