Electrochemical Properties of Silicon Dioxide Particles synthesized by Using Sol-gel Method

Hien Ngoc Thi Le,정혜경 한국물리학회 2013 새물리 Vol.63 No.2

A novel way to synthesize silicon-dioxide particles by using silicon tetrachloride and 2- methoxyethanol and a sol-gel method has been developed. Different sizes and densities of the silicon-dioxide (SiO2) particles were formed on Ni foils at different spin-coating speeds of 2000, 3000, and 4000 rpm for 20 seconds. Scanning electron microscopy results showed that SiO2 particles had been at all speeds and that the distribution of particles at 4000 rpm was the best. Cyclic voltammetry and electrochemical impedance spectroscopy were also used to characterize the electrochemical properties of the obtained samples for energy-storage-device applications

Enhanced supramolecular recognition capability of gamma cyclodextrin-graphite oxide-carbon nanotube composite

Le, Hien Thi Ngoc,Jeong, Hae Kyung Pergamon Press 2017 Electrochimica Acta Vol. No.

<P><B>Abstract</B></P> <P>The γ-cyclodextrin–graphite oxide–carbon nanotube (γCD–GO–CNT) composite has shown the best capability and sensitivity of supramolecular recognition compared to the other two CD-GO-CNT composites (αCD-GO-CNT and βCD-GO-CNT) in our previous study. The biggest CD (γCD) was very important in the formation of the supramolecular complex and made the detection of the biomolecules easier. In this report, significantly improved supramolecular recognition capability of γCD–GO–CNT is introduced by using thermally reduced GO (TRGO), instead of typical GO. New synthesized γCD–TRGO–CNT composite film shows lower electrochemical impedance, higher carbon to oxygen atomic ratio, and larger surface area compared to the γCD–GO–CNT composite film, resulting in higher sensitivity and capability in the supramolecular recognition. The sensitivity, defined as the slope of the maximum response current versus guest molecule concentration graph, increases significantly from 4.42 to 9.44 for dopamine and from 2.21 to 4.15 for ascorbic acid. The excellent enhancement of the supramolecular recognition of the γCD–TRGO–CNT composite is attributed to TRGO. It is, therefore, concluded that it is very important to load γCD in the composite as well as to decrease the electrochemical impedance for effective electrochemical biosensors.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The γ-cyclodextrin- thermally reduced graphite oxide-carbon nanotube composite film was successfully synthesized. </LI> <LI> The γCD-TRGO-CNT composite shows enhanced supramolecular recognition capability compared to the γCD-GO-CNT composite. </LI> <LI> Sensitivity of the γCD-TRGO-CNT composite dramatically increased by a factor of two compared to the γCD-GO-CNT composite. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Investigation of the Electrochemical Responses of Graphite Oxide-Carbon Nanotube Composite Films to Biomolecules

Hien Thi Ngoc LE,정혜경 한국물리학회 2017 New Physics: Sae Mulli Vol.67 No.4

Graphite-oxide and carbon-nanotube (GO_CNT) composite films are synthesized by using a simple chemical method and characterized for biosensor applications. Two kinds of graphite oxide were used. One is typical graphite oxide (GO), and the other is thermally-reduced graphite oxide (TRGO). The electrochemical properties of the two composite films (GO_CNT and TRGO_CNT) was investigated when three kinds of biomolecules (dopamine, thioridazine, and ascorbic acid) are applied. Compared to the GO_CNT composite film, the TRGO_CNT composite film is found to show a significantly high electrochemical response to the all the molecules due to its higher surface area and lower impedance.

Synthesis and Characterization of Nitrogen-doped Activated Carbon by Using Melamine

Hien Ngoc Thi Le,정혜경 한국물리학회 2015 새물리 Vol.65 No.1

A simple method to synthesize nitrogen-doped activated carbon by using simple thermal treatment of a mixture of activated carbon and melamine was introduced. About 6 at% of nitrogen were successfully doped into the activated carbon, and it affected the electrochemical properties dramatically. The nitrogen-containing groups could be intercalated and diffused into the pores of the activated carbon and blocked them, resulting in decreased surface area and volume. However, the cyclic voltammetric current density was significantly increased in the nitrogen-doped activated carbon compared to the bare activated carbon, demonstrating the positive effect of nitrogen doping on the performance of supercapacitors and energy storage devices.

Cyclodextrin-Graphite Oxide-Carbon Nanotube Composites for Electrochemical Supramolecular Recognition

Le, Hien Thi Ngoc,Jeong, Hae Kyung Elsevier 2017 ELECTROCHIMICA ACTA Vol.232 No.-

<P><B>Abstract</B></P> <P>Three different cyclodextrins (α, β, and γCD) are used in a synthesis of free-standing cyclodextrin-graphite oxide-carbon nanotube (CD-GO-CNT) composite films and compared for the electrochemical supramolecular recognition. All composites show very good electrochemical response to three biomolecules (dopamine, ascorbic acid, and thioridazine), and the response of the electrical current is linearly proportional to the concentration of the biomolecules. The γCD-GO-CNT composite gives the best electrochemical supramolecular recognition performance among the other composites (αCD-GO-CNT and βCD-GO-CNT) because of the biggest cavity of γCD (0.95nm of diameter) compared to αCD (0.57nm of diameter) and βCD (0.78nm of diameter). The composite of bigger size CD is more sensitive, resulting that αCD-, βCD-, and γCD-GO-CNT composites are in the order of the increasing sensitivity, to the response, and detail results will be discussed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Successful synthesis of the free standing α, β, and γ cyclodextrin-graphite oxide-carbon nanotube composite films. </LI> <LI> Investigation and comparison of three kinds of the cyclodextrin composites for supramolecular recognition capability. </LI> <LI> Highest sensitivity of the γ cyclodextrin-graphite oxide-carbon nanotube composite film compared to the others. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

탄소나노튜브 네트워크에 있는 사이클로덱스트린-그라핀옥사이드 필름

래히옌 ( Hien Ngoc Thi Le ),장윤수 ( Yun Soo Jang ),정혜경 ( Hae Kyung Jeong ) 한국화상학회 2013 한국화상학회지 Vol.19 No.3

Cyclodextrin-graphene oxide film on the carbon nanotubes matrix is synthesized by a simple chemical method, and physical, chemical, and electrochemical properties of the composites are investigated. Capacitance is improved markedly up to 84 F/g with chemically reduced graphene oxide at the current density of 0.7 A/g compared with 2.6 F/g of the previous composites having no graphene oxide. The new composites electrodes show more redox processes, originated from the graphene oxide, in the cycle voltammetry compared to the previous composites which had no graphene oxide, indicating enhancement of capacitances. Following improved energy density of the new composite makes it possible to be an electrode of the hybrid capacitors.

The Values of Acoustic Radiation Force Impulse Elastography of Liver in Evaluating the Degree of Liver Fibrosis in Alcoholic Liver Disease

( Le Thi Thu Hien ),( Ha Phuong Linh ),( Tran Huu Ngoc ) 대한간학회 2021 춘·추계 학술대회 (KASL) Vol.2021 No.1

Applying Stochastic Fractal Search Algorithm (SFSA) in Ranking the Determinants of Undergraduates Employability: Evidence from Vietnam

DINH, Hien Thi Thu,CHU, Ngoc Nguyen Mong,TRAN, Van Hong,NGUYEN, Du Van,NGUYEN, Quyen Le Hoang Thuy To Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.12

Employability has recently become the first target of the national higher education. Its model has been updated to catch the new trend of Industry 4.0. This paper aims at analyzing and ranking the determinants of undergraduate employability, focusing on business and economics majors in Ho Chi Minh City, Vietnam. In-depth interviews with content analysis have been primarily conducted to reach an agreement on a key group of factors: human capital, social capital, and identity. The Stochastic Fractal Search Algorithm (SFSA) is then applied to rank the sub-factors. Human capital is composed of three major elements: attitude, skill, and knowledge. Social capital is approached at both structural and cognitive aspects with three typical types: bonding, bridging, and linking. The analysis has confirmed the change of priority in employability determinants. Human capital is still a driver but the priority of attitude has been confirmed in the contemporary context. Then, social capital with the important order of linking, bridging, and bonding is emphasized. Skill, knowledge, and identity share the least weight in the model. It is noted that identity is newly proposed in the model but a certain role has been found. The findings are crucial for education strategies to enhance university graduate employability.

Whole-exome sequencing identifies two novel missense mutations (p.L111P and p.R3048C) of RYR3 in a Vietnamese patient with autism spectrum disorders

Thu Hien Nguyen,Thi Thanh Ngan Nguyen,Bac Viet Le,Ngoc Minh Thanh,Thi Kim Lien Nguyen,Van Hai Nong,Huy Hoang Nguyen 한국유전학회 2017 Genes & Genomics Vol.39 No.3

Autism spectrum disorders (ASDs) are a group of neurodevelopmental disorders characterized by ritualistic- repetitive behaviors and impaired verbal and non-verbal communication. Boys are more likely to be diagnosed with ASD than girls. Genetics have been shown to play a key role in the etiology of autism. Many genes were found to be implicated in the inheritance of idiopathic autism. Analysis of mutation abnormalities associated with autism contributes significantly to the identification of autism candidate genes. Whole-exome sequencing has been shown as an application of the next generation sequencing technology used to determine the variations of all coding regions, or exons of the known genes. In the present study, we have found two novel heterozygous missense mutations (p.L111P and p.R3048C) on the RYR3 gene, which was located in the autism susceptibility region (15q14-q15) in a 9-year-old boy with ASD. Therefore, the sequence missense mutations provide the first suggestive link between a genetic abnormality in the RYR3 gene and a neurodevelopmental disorder.

Factors Affecting Training Quality and Student Satisfaction: An Empirical Study in Vietnam

Duong Thi Hai LE,Long Duc Bao NGUYEN,Chau Le Ngoc PHAN,Tuan Minh VU,Hien Thu PHAN 한국유통과학회 2022 The Journal of Asian Finance, Economics and Busine Vol.9 No.4

The purpose of this study was to determine the factors that influence the training quality of Van Lang University’s Finance Banking faculty (VLU). Another goal was to discover a way to increase training quality and give students the greatest experience possible. To achieve the following goals, qualitative research was used in combination with questionnaires and document reviews. A total of 700 surveys were sent out, with 624 responses. In-depth interviews with 12 graduates were conducted during the qualitative stage to obtain their perspectives on their time at VLU. The impact of five factors (instructor qualification, facility, education program, accessibility, and student interaction) was investigated in this study, and the findings revealed that all of them significantly mediated the relationship with the training quality of VLU’s Finance Banking faculty. The findings show that it is vital to improve the training quality to increase student satisfaction and boost their academic abilities. With the framework from this study, policymakers, researchers, and institutes can cooperate in developing and upgrading the general training quality at higher education institutions in Vietnam. Improving the training quality of a faculty will continue to be a challenge. Therefore, this is a topic that requires continuous research.