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    The Y3+ Donor-Doped CCTO (Ca0.95Y0.05Cu3Ti4O12) Dielectric Fillers for Electrical Output Enhancement of Flexible Triboelectric Nanogenerator
    (2026-06-03)
    Saichompoo, Kittipan
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    Rattanawongwiboon, Thitirat
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    Kingkam, Wilasinee
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    Pakawanit, Phakkhananan
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    The escalating wearable electronic devices with their flexible energy sources demand has rendered the imperative scientific challenge on the development of materials for the flexible triboelectric nanogenerators (F-TENG), one of advanced energy harvesting systems. Dielectric material optimization, the Y<sup>3+</sup> donor-doped calcium copper titanate based on exactly stoichiometric Ca<inf>0.95</inf>Y<inf>0.05</inf>Cu<inf>3</inf>Ti<inf>4</inf>O<inf>12</inf> (CCTYO), serves as a critical pathway in this work for achieving enhanced F-TENG via compositing with the polydimethylsiloxane (PDMS) polymer. The enhancement of electrical output has garnered substantial interest owing to its increased relative permittivity ((Formula presented.)). The influence of the loaded CCTYO amounts on structure, morphologies, dielectric properties, and electrical output, including open-circuit voltage (V<inf>OC</inf>), short-circuit current (I<inf>SC</inf>) and power density for PDMS/CCTYO composites is investigated. As compared with loading undoped CCTO, the additional Y<sup>3+</sup> can improve higher F-TENG output by increasing the (Formula presented.) along with maintaining the loss tangent (tan δ < 0.02) at optimized condition. The appropriate amounts of CCTYO 0.75 wt% make the PDMS/CCTYO F-TENG to achieve V<inf>OC</inf> of ∼76.4 V (8.5 V/cm<sup>2</sup>) and I<inf>SC</inf> of ∼130.0 μA (14.4 μA/cm<sup>2</sup>), which were higher than pristine PDMS for 2.7 and 4.3 times. The power density of 53 µW/cm<sup>2</sup> is 8.9 times higher than that of 6.3 µW/cm<sup>2</sup> from the pristine PDMS. This study also provides a COMSOL multiphysics simulation, bridging laboratory experiments, for quantifying the triboelectric capability of dielectric materials.
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    Synthesis and characterization of CH3NH3PbI3 and CH3NH3PbI(3-x)Clx perovskite solar cell materials
    (2019-11-18)
    Kamonpha, Phitsamai
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    Padchasri, Jintara
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    Rujirawat, Saroj
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    ;
    Kidkhunthod, Pinit
    The emerging of perovskite solar cell has attracted many interests in the synthesis and characterization of hybrid perovskite materials related to methylammonium iodide (MAI) due to various promising properties. In this work, we found a faster way to synthesize hybrid perovskite CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> and CH<inf>3</inf>NH<inf>3</inf>PbI<inf>(3-x)</inf>Cl<inf>x</inf> (x = 0,1,2) powders from a different solvent in the preparation process of MAI precursor. In addition, it was found that in CH<inf>3</inf>NH<inf>3</inf>PbI<inf>(3-x)</inf>Cl<inf>x</inf> powders, as characterized by XRD and XAS, with a solid-state method employed Cl atoms cannot directly substitute for I in the perovskite (ABX<inf>3</inf>) structure.
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    Research Article Biosynthesis of Silver Nanoparticles Using Garcinia cowa Aqueous Leaf Extract and Their Antifungal Activity Against Durian Dieback Pathogen
    (2023-09-01) ;
    Khejonrak, Awadol
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    Kamonpha, Phitsamai
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    Ruangvittayanon, Anuchit
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    Pakdeepromma, Sirichatnach
    Silver nanoparticles (AgNPs) were synthesized under different pH and reaction time using the Garcinia cowa aqueous leaf extract. The formation, crystal structure and morphology of synthesized AgNPs were investigated using UV-Vis spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. The UV-Vis result indicated that the AgNPs were synthesized using Garcinia cowa aqueous leaf extract at all pH conditions within 10 min. The synthesis of AgNPs was significantly affected by pH condition which was shown by the TEM micrographs. The particle sizes of AgNPs were in a nano-sized range; 6.30 ± 3.52 nm for pH 4, 3.87 ± 2.51 nm for pH 7 and 13.97 ± 11.84 nm for pH 10. Furthermore, the AgNPs prepared in pH 4, pH 7 and pH 10 (120 min reaction time) at different concentrations were assessed for their antifungal activity against durian dieback pathogen. It was found that the 800 mL/L of AgNPs prepared at pH 7, the smallest particle size and good dispersion, showed the highest inhibition mycelial growth at 47.33%, whereas the larger nanoparticles prepared at pH 4 and pH 10 conditions showed lower inhibition of mycelial growth at 43.22% and 32.55%, respectively.
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    Influence of Pb(In1/2Nb1/2)O3 on the phase transitions, electrical, and thermal properties of a PbZrO3 ceramic
    (2011-10-01) ; ;
    Niemcharoen, Surasak
    ;
    ;
    The solid solution of a (1-x)PbZrO<inf>3</inf>-xPb(In<inf>1/2</inf>Nb <inf>1/2</inf>)O<inf>3</inf> (PZ-PIN) system, with x=0.00-0.50, was synthesized using the wolframite precursor method. The effects of the PIN content on the crystal structure, and the electrical and thermal properties of a PbZrO <inf>3</inf> ceramic were investigated using X-ray diffraction, dielectric spectroscopy, hysteresis measurement, and differential scanning calorimetry techniques. Furthermore, the morphology and grain size were determined using scanning electron microscopy. The results indicated that the pure perovskite phase was obtained for all compositions, and the solid solution, PZ-PIN, changed from orthorhombic to rhombohedral symmetry when the amount of PIN increased. A ferroelectric intermediate phase began to appear between the paraelectric and the antiferroelectric phases of pure PZ, with increasing PIN content. The temperature range width of the ferroelectric phase also increased continuously with increasing PIN. At room temperature, the polymorphic phase transition (PPT) was identified from the orthorhombic to the rhombohedral phase in (1-x)PZ-xPIN at the composition, x=0.40. The ceramics (x=0.40) with PPT close to room temperature exhibited excellent electrical properties (ε<inf>rmax</inf>= 33240 and P<inf>r</inf>=26.94 μC/cm<sup>2</sup>). © 2011 The American Ceramic Society.
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    Synchrotron-based NEXAFS analysis of thermal-treated diamond-like carbon films
    (2020-10-01)
    Chunjaemsri, Thanun
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    Chanlek, Narong
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    Nakajima, Hideki
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    Rujirawat, Saroj
    Diamond-like carbon (DLC) film properties are known to vary with important factors such as the ratio of sp<sup>3</sup> to sp<sup>2</sup> hybridization, film thickness, and contaminations. In this work, the carbon bonding contents in DLC thin films, thermal-treated with various temperatures between room temperature to 250 °C, were studies by near-edge X-ray absorption fine structure (NEXAFS), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. From NEXAFS measurements, the sp<sup>3</sup>/sp<sup>2</sup> ratios of DLC films were found to be unaffected by the thermal treatments. The results indicate that thermal treatment below 250 °C does not affect the carbon bonding contents in DLC thin film.
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    Local structure elucidation and reaction mechanism of light naphtha aromatization over Ga embedded H-ZSM-5 zeolite: Combined DFT and experimental study
    (2020-10-15)
    Wongnongwa, Yutthana
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    Kidkhunthod, Pinit
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    Pengpanich, Sitthiphong
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    Thavornprasert, Kaew arpha
    Local structures and mechanisms for n-pentane aromatization on Ga embedded H-ZSM-5 zeolite (Ga/ZSM-5) were elucidated using Synchrotron-based X-ray absorption spectroscopy (XAS) and density functional theory (DFT) calculations to understand the role of Ga/ZSM-5 zeolite in aromatics synthesis. XAS data suggests that Ga ligates with four oxygen or four hydrogen atoms. Catalytic tests results suggest that conversion by Ga/ZSM-5 catalyst cannot occur via C6–C8 non-aromatic intermediates, while the availability of Ga metal sites promotes the aromatization of C2 and C3 species. Therefore, conversion of n-pentane to benzene or toluene comprises four steps, i) cracking, ii) GaH<inf>2</inf> activation, iii) cyclization, and iv) dehydrogenation. Our model predicts the key intermediate in n-pentane aromatization on Ga/ZSM-5 zeolite to be a five-membered Ga-C4 ring structure. The ring undergoes expansion to form a seven-membered Ga-C6 ring. Moreover, we discuss thermodynamics and kinetic results for the benzene and toluene formation pathways. Our results provide new finding for the role of Ga/ZSM-5 zeolites in n-pentane aromatization processes.
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    High piezoelectric response in lead free 0.9BaTiO3-(0.1-x)CaTiO3-xBaSnO3 solid solution
    (2017-08-01)
    Mayamae, Jitkasem
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    ; ;
    Bongkarn, Theerachai
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    Lead free piezoelectric in the ternary system of 0.9BaTiO<inf>3</inf>-(0.1-x)CaTiO<inf>3</inf>-xBaSnO<inf>3</inf> [BCT-xBS], where x = 0.00–0.075, was fabricated via a conventional solid state reaction. The effect of substituting BCT with BS on the crystal structure as well as dielectric, ferroelectric and strain behavior was investigated systematically in order to search for outstanding actuating performances in lead free piezoelectric ceramics. A ferroelectric phase diagram of BT-CT-BS was established in this work, and a multi-ferroelectric phase composition was designed near ambient temperature, based on an established phase diagram. The BS substitute depressed the ferroelectric-paraelectric phase temperature slightly and raised the transition temperatures of O-T phase transformations, thus, the orthorhombic phase could be stabilized above the ambient temperature with x > 0.05. As a result, the polymorphic phase composition showed outstanding piezoelectric values of k<inf>p</inf> = 41.7%, d<inf>33</inf> = 469 pC/N and d<inf>33</inf><sup>*</sup> = 1335 pm/V@10 kV/cm, which are suitable for lead free piezoelectric actuator applications.
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    Dielectric, ferroelectric and piezoelectric properties of the lead free 0.9BaTiO3-(0.1- x)Bi0.5Na0.5TiO3- x Bi(Mg0.5Ti0.5)O3 solid solution
    (2016-01-02)
    Mayamae, Jitkasem
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    ;
    Niemchareon, Surasak
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    ;
    Solid solution of 0.9BaTiO<inf>3</inf>-(0.1-x)Bi<inf>0.5</inf>Na<inf>0.5</inf>TiO<inf>3</inf>-xBi(Mg<inf>0.5</inf>Ti<inf>0.5</inf>)O<inf>3</inf> (BT-BNT-xBMT) system, where x = 0.00, 0.02, 0.04, 0.06, 0.08, 0.10, was synthesized by the solid state reaction. Dense BT-BNT-xBMT ceramics were obtained by sintering at 1,150-1,250C for 4 h. The effect of BMT on crystal structure and electrical property of BT-BNT ceramics was investigated as a function of composition, x, using X-ray diffraction, dielectric spectroscopy, hysteresis and strain measurements. The crystal structure of solid solution BT-BNT-xBMT, where x = 0.00-0.10, successively transforms from tetragonal to pseudocubic symmetry, with increased BMT concentration. Temperature dependence of dielectric constant (ε<inf>r</inf>) and dielectric loss (tanδ) for BT-BNT-xBMT at various frequencies showed that phase transition of ceramics changed from ferroelectric to relaxor-like behavior as BMT content increased. Furthermore, remanent polarization (P<inf>r</inf>), coercive field (E<inf>c</inf>) and the normalized strain (d<inf>33</inf>∗) of BT-BNT-xBMT ceramics tend to decrease with increasing BMT concentration.
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    Phase transition behavior of the (1-x) PbZrO 3-x Ba (Al 1/2 Nb 1/2) O 3 solid solution
    (2012-10-01) ; ; ;
    Niemcharoen, Surasak
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    Solid solution of the (1-x)PbZrO <inf>3</inf>-xBa(Al <inf>1/2</inf>Nb <inf>1/2</inf>)O <inf>3</inf> system, with x = 0.02-0.30, was prepared using solid state reaction. The effect of Ba(Al <inf>1/2</inf>Nb <inf>1/2</inf>)O <inf>3</inf> on phase transitions and thermal and electrical properties was investigated. The stability of ferroelectric phase in pure PZ was found to improve with increasing BAN content, which corresponded to the increased tolerance factor (t) of solid solution. In comparison to other systems, results in this study indicated that the tolerance factor can predict the ferroelectric (FE)/antiferroelectric (AFE) stability of PZ-based solid solution. If the t value of solid solution is higher than pure PZ, the FE phase can be induced. On the other hand, the AFE phase is stabilized when the t value of solid solution is lower than pure PZ. © 2012 The American Ceramic Society.
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    Effect of thermal annealing on the structure of LiCoO2 powders prepared by co-precipitation method
    (2021-12-01)
    Khejonrak, Awadol
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    Chanlek, Narong
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    Triamnak, Narit
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    Chirawatkul, Prae
    Lithium cobalt oxide (LiCoO<inf>2</inf>) powder was prepared by co-precipitation method and annealed at different temperatures of between 300 and 700 °C. The effect of annealing temperature and effect washing process with deionized water on the crystal structures of the prepared LiCoO<inf>2</inf> powders were thoroughly studied by Synchrotron powder X-Ray Diffraction (Syn-XRD), X-ray Absorption Spectroscopy (XAS), Dispersive Raman Microscopy (Raman) techniques. The change in chemical composition as a function of annealing temperature was also investigated by X-ray Photoelectron Spectroscopy (XPS) technique. The crystal structural results identified the phase evolution of the prepared LiCoO<inf>2</inf> powders upon heat treatment. The formation of HT-LiCoO<inf>2</inf> phase was observed at annealing temperature as low as 300 °C.