Hydrothermal synthesis of In₂O₃ nanocubes for highly responsive and selective ethanol gas sensing

Nguyen, Thuy T.D.,Choi, Ha-Nui,Ahemad, M. Jamir,Van Dao, Dung,Lee, In-Hwan,Yu, Yeon-Tae Elsevier 2020 Journal of Alloys and Compounds Vol.820 No.-

<P><B>Abstract</B></P> <P>Indium oxide nanocubes (NCs) were prepared via a simple, template-free hydrothermal method at low temperature; the so-obtained structures exhibited large surface area (47.67 m<SUP>2</SUP>/g) and Barrett−Joyner−Halenda (BJH) adsorption average pore diameter (11.92 nm), both higher than for commercial In<SUB>2</SUB>O<SUB>3</SUB> nanoparticles. At the optimal temperature of 300 °C, the In<SUB>2</SUB>O<SUB>3</SUB> NCs-based sensor showed a superior response of 85–100 ppm ethanol, 3.4 times higher than that of the commercial one based on In<SUB>2</SUB>O<SUB>3</SUB> NPs, and also faster response time (15 s) than the commercial device (60 s). The better sensing performance of the synthesized In<SUB>2</SUB>O<SUB>3</SUB> NCs can be attributed to its unique properties that include large BET surface area and BJH adsorption average pore diameter as well as abundance of sharp edges and tips, which result in high surface to volume ratios for the gas adsorption and diffusion processes, facilitating the charge-transfer and sensing reactions at the gas–solid interfaces. In addition, the In<SUB>2</SUB>O<SUB>3</SUB> NCs exhibited excellent selectivity to ethanol among other target gases (CO, CH<SUB>4</SUB>, CH<SUB>3</SUB>CHO, H<SUB>2</SUB>, and CH<SUB>3</SUB>COCH<SUB>3</SUB>). This work provides an effective design pathway for ethanol sensors based on In<SUB>2</SUB>O<SUB>3</SUB> NCs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> In<SUB>2</SUB>O<SUB>3</SUB> nanocubes are prepared via a template-free method at low temperature. </LI> <LI> In<SUB>2</SUB>O<SUB>3</SUB> nanocubes show high surface area and large BJH adsorption pore diameter. </LI> <LI> In<SUB>2</SUB>O<SUB>3</SUB> nanocubes show high sensing response and good selectivity to ethanol gas. </LI> <LI> Our finding opens an effective pathway to develop ethanol sensors. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The graphical abstract for In<SUB>2</SUB>O<SUB>3</SUB> nanocubes ethanol gas sensing.</P> <P>[DISPLAY OMISSION]</P>

Exchange-Driven Colective Behavior in a 3D Array of Nanoparticles

Ha M. Nguyen,Pai-Yi Hsiao 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5

A Monte Carlo simulation is performed in a cubic lattice of interacting identical Stoner-Wohlfarth nanoparticles. The model system is a randomly-anisotropic Heisenberg spin system with a small anisotropy-to-exchange ratio D=J = 3:5. The dc susceptibility, Χdc(T), shows a Curie-Weiss-like transition at a temperature TC/J 1.5, followed by alow-temperature glassy behavior manifested by cusps in both the zero-field-cooled and the field-cooled curves. The ac susceptibility, Χac(T,ω), at various frequencies, ω, shows that with decreasing temperature, a non-Arrhenius dispersive peak occurs at Tb(ω), succeeded by another dispersionless peak at Tg/J 1.20 in the in-phase part, Χ'(T,ω), of Χac(T,ω) while the out-of-phase part, Χ''(T,ω), shows only one peak. A dynamic scaling analysis shows that the system exhibits a critical slowing-down at Tg with a quite small exponent zυ 1.65. However, no universal collapse is seen for the fully-scaled data of Χ''(T,ω). These observed behaviors are interpreted under the droplet-like hypothesis that the formation and development of exchange-induced correlated clusters drive ensembles of nanoparticles undergoing a transition from a paramagnetic order to a short-range order (SRO) at TC, followed by a transition at Tg to the magnetic state in which a magnetic glassy order and a magnetic quasi-long-rangeorder (QLRO) coexist. In addition, our simulation shows that the onset of the latter transition, which is peculiarly manifested by the dispersionless peak, occurs only for those ensembles possessing the anisotropy strength in the region 1.0 ≤ D/J ≤ 5.0. When this range is exceeded, this onset totally suppressed. The reason that the QLRO is prohibited in ensembles of strong random anisotropy may account for this phenomenon.

Effect of Plasma and NaOH Treatment for Rice Husk/PP Composites

Nguyen, M.H.,Kim, B.S.,Ha, J.R.,Song, J.I. VSP 2011 Advanced Composite Materials Vol. No.

OPTIMIZATION BASED APPROACH FOR PI CONTROLLER TUNING FOR OPTIMAL CONTROL OF FIRST ORDER PROCESSES WITH CONSTRAINTS

M. Masum Jujuly,Nguyen Viet Ha,Moonyong Lee 제어로봇시스템학회 2010 제어로봇시스템학회 국내학술대회 논문집 Vol.2010 No.5

Knowledge and Perceptions of Influenza Vaccinations Among College Students in Vietnam and the United States

Akiko Kamimura,Ha N. Trinh,Shannon Weaver,Alla Chernenko,Maziar M. Nourian,Nushean Assasnik,Hanh Nguyen 대한예방의학회 2017 Journal of Preventive Medicine and Public Health Vol.50 No.4

Objectives: Influenza is a significant worldwide public health issue. Knowledge and perceptions regarding the flu vaccination are associated with whether individuals obtain the vaccination. The purpose of this study was to examine how such perceptions were related to knowledge and self-efficacy regarding influenza and the flu vaccination in Vietnam and the US. Methods: College students (n=932) in Vietnam (n=495) and the US (n=437) completed a self-administered survey regarding knowledge and perceptions of influenza vaccinations in September and October 2016. Results: Vietnamese participants reported significantly lower levels of awareness about flu risk, higher levels of negative attitudes toward flu vaccination, lower levels of knowledge about the flu and vaccination, and lower levels of self-efficacy than US participants. Higher levels of flu and flu vaccination knowledge and self-efficacy regarding general responsible health practices were associated with lower levels of negative perceptions of flu risk and attitudes toward vaccination. At the same time, self-efficacy regarding responsible health practices was associated with higher levels of awareness of flu risk and lower levels of negative attitudes toward vaccination. Self-efficacy regarding exercise was associated with lower levels of perceptions of flu risk and higher levels of negative attitudes toward vaccination. Conclusions: Vietnam could benefit from influenza education based on this comparison with the US. In both countries, knowledge and self-efficacy were found to be important factors influencing perceptions of influenza risk and vaccination.

Synthesis of aryl-substituted pyridines via cyclization of N,N-dialkylanilines with ketoxime carboxylates under metal-organic framework catalysis

Phuong T.M. Ha,Binh T.T. Le,Trung C. To,Son H. Doan,Tung T. Nguyen,Nam T.S. Phan 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.54 No.-

Iron-organic framework Fe3O(BPDC)3 was synthesized, and subsequently utilized as an productive heterogeneous catalyst for the cyclization reaction of N,N-dialkylanilines with ketoxime carboxylates to produce aryl-substituted pyridines. This iron-organic framework catalyst demonstrated remarkably higher catalytic productivity for the synthesis of aryl-substituted pyridines as compared to numerous conventional homogeneous catalysts as well as MOF-based catalysts. It was possible to reuse the iron- framework catalyst in the cyclization transformation for numerous cycles without a noticeable decline in activity. To our best knowledge, this is the first heterogeneous catalytic approach towards the synthesis of aryl-substituted pyridines from ketoximes.

Experimental study on two-phase flow natural circulation in a core catcher cooling channel for EU-APR1400 using air-water system

Song, K.W.,Nguyen, T.H.,Ha, K.S.,Kim, H.Y.,Song, J.,Park, H.S.,Revankar, S.T.,Kim, M.H. North-Holland Pub. Co 2017 Nuclear engineering and design Vol.316 No.-

<P>Ex-vessel core catcher cooling system driven by natural circulation is designed using a full scaled air-water system. A transparent half symmetric section of a core catcher coolant channel of a pressurized water reactor was designed with instrumentations for local void fraction measurement and flow visualization. Two designs of air-water top separator water tanks are studied including one with modified 'super-step' design which prevents gas entrainment into down-comer. In the experiment air flow rates are set corresponding to steam generation rate for given corium decay power. Measurements of natural circulation flow rate, spatial local void fraction distribution and re-wetting time near the top wall are carried out for various air flow rates which simulate boiling-induced vapor generation. Since heat transfer and critical heat flux are strongly dependent on the water mass flow rate and development of two-phase flow on the heated wall, knowledge of two-phase flow characteristics in the coolant channel is essential. Results on flow visualization showing two phase flow structure specifically near the high void accumulation regions, local void profiles, rewetting time, and natural circulation flow rate are presented for various air flow rates that simulate corium power levels. The data are useful in assessing the cooling capability of and safety of the core catcher system. (C) 2017 Elsevier B.V. All rights reserved.</P>

Knowledge and Perceptions of Influenza Vaccinations Among College Students in Vietnam and the United States

Kamimura, Akiko,Trinh, Ha N.,Weaver, Shannon,Chernenko, Alla,Nourian, Maziar M.,Assasnik, Nushean,Nguyen, Hanh The Korean Society for Preventive Medicine 2017 Journal of Preventive Medicine and Public Health Vol.50 No.4

Objectives: Influenza is a significant worldwide public health issue. Knowledge and perceptions regarding the flu vaccination are associated with whether individuals obtain the vaccination. The purpose of this study was to examine how such perceptions were related to knowledge and self-efficacy regarding influenza and the flu vaccination in Vietnam and the US. Methods: College students (n=932) in Vietnam (n=495) and the US (n=437) completed a self-administered survey regarding knowledge and perceptions of influenza vaccinations in September and October 2016. Results: Vietnamese participants reported significantly lower levels of awareness about flu risk, higher levels of negative attitudes toward flu vaccination, lower levels of knowledge about the flu and vaccination, and lower levels of self-efficacy than US participants. Higher levels of flu and flu vaccination knowledge and self-efficacy regarding general responsible health practices were associated with lower levels of negative perceptions of flu risk and attitudes toward vaccination. At the same time, self-efficacy regarding responsible health practices was associated with higher levels of awareness of flu risk and lower levels of negative attitudes toward vaccination. Self-efficacy regarding exercise was associated with lower levels of perceptions of flu risk and higher levels of negative attitudes toward vaccination. Conclusions: Vietnam could benefit from influenza education based on this comparison with the US. In both countries, knowledge and self-efficacy were found to be important factors influencing perceptions of influenza risk and vaccination.

Fattigation-platform nanoparticles using apo-transferrin stearic acid as a core for receptor-oriented cancer targeting

Amin, Hardik H.,Meghani, Nilesh M.,Park, Chulhun,Nguyen, Van Hong,Tran, Thao Truong-Dinh,Tran, Phuong Ha-Lien,Lee, Beom-Jin Elsevier 2017 Colloids and Surfaces B Vol.159 No.-

<P><B>Abstract</B></P> <P>A major hurdle in cancer treatment is the precise targeting of drugs to the cancer site. As many cancer cells overexpress the transferrin receptor (TfR), the transferrin (Tf)-TfR interaction is widely exploited to target cancer cells. In this study, novel amphiphilic apo-Tf stearic acid (TfS) conjugates were prepared and characterized by Fourier transform infrared (FTIR) spectroscopy, matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry, and trinitrobenzenesulfonic acid (TNBS) assay. The prepared TfS conjugates were readily self-assembled in water to form nanoparticles (NPs), consisting of TfS as a core of NPs, whose sizes and zeta potentials were determined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and a particle size analyzer. Hydrophilic water-soluble doxorubicin (DOX) was chosen as a model drug. DOX-loaded TfS NPs (NP+DOX), prepared by the adsorption of DOX on the NP surface via the incubation method, were analyzed for their cell targeting and killing efficiencies in TfR-overexpressing A549 and HCT116 cell lines by MTT assay, confocal microscopy, and fluorescence assisted cell sorting (flow cytometry). The data showed that NP+DOX exhibited improved cancer cell targeting and killing properties compared to that reported for free DOX. Further, the cytotoxic efficiency of NP+DOX was comparable to that of PEGylated liposomal product, Doxil<SUP>®</SUP>, while its cellular uptake was higher than that of Doxil<SUP>®</SUP>. Thus, this novel receptor-based TfS NP drug delivery system has great potential to target TfR-overexpressing cancer cells without off-target effects.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Apo-transferrin and stearic acid conjugate could form self-assembled NP. </LI> <LI> Apo-transferrin and stearic acid were used as a NP core. </LI> <LI> Drug-loaded NPs showed superior cancer cell targeting and killing efficiency. </LI> <LI> The prepared NPs were as comparable as the PEGylated liposomal product, Doxil<SUP>®</SUP>. </LI> <LI> The NP system has potential to deliver both hydrophilic and hydrophobic drug. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Mechanistic pathway of prepared TfS NPs for cellular uptake and trafficking in transferrin receptor over-expressing cancer cells.</P> <P>[DISPLAY OMISSION]</P>

Interacting Superparamagnetism in La0.7Sr0.3MnO3 Nanoparticles

Le Van Hong,D. H. Manh,Ha M. Nguyen,N. X. Phuc,Y. D. Yao 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5

ThemagneticorderofLa0:7Sr0:3MnO3nanoparticles(NPs)fabricatedinaSPEXD800milwas systematicalystudied. TheLa0:7Sr0:3MnO3 nanocrystalsgrowfromthemiledconstituentoxides during the miling proceses. The magnetization data obtained by using a SQUID magnetometer show the NPs as a superparamagnet in terms of anhysteretic curves near rom temperature. Un- overlaping of the scaled M(Hext;T)=Ms vs. Hext=T plots and the dc susceptibility obeying the Curie-Weis behavior rather than the Curie law at high temperatures provide evidence that the NPs are interacting superparamagnetic ensembles. A mean-eld corection to the Langevin func- tion L([Hext+M]=kBT) worked wel for the magnetic ordering of the NPs. By means of the Langevinting,thediameteroftheNPwasestimatedtobelowerthan15nm,dependingonthe miling time. The saturation magnetization of NPs varied from 48.5 em/g to 19 emu/g, with the highervaluecorespondingtoalargerparticlesize. Acore-shelstructureoftheNPwasadopted, with the NP having the core-shel magneticaly-eective mas density.