KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/kmitl/1

Browse

Search Results

Now showing 1 - 10 of 17

Some of the metrics are blocked by your
consent settings
Preface
(2025-02-01)
Yimnirun, Rattikorn
;
Kidkhunthod, Pinit
;
Kaewkhao, Jakrapong
;
Vittayakorn, Naratip
;
D'Angelo, Paola
Some of the metrics are blocked by your
consent settings
Preface-The 5th international conference on Smart Materials and Nanotechnology 2020 (SmartMat@2020)
(2022-10-01)
Kaewkhao, Jakrapong
;
Kidkhunthod, Pinit
;
Vittayakorn, Naratip
;
Yimnirun, Rattikorn
;
D'Angelo, Paola
Some of the metrics are blocked by your
consent settings
Preface
(2022-09-01)
Kaewkhao, Jakrapong
;
Kidkhunthod, Pinit
;
Vittayakorn, Naratip
;
Yimnirun, Rattikorn
;
D'Angelo, Paola
Some of the metrics are blocked by your
consent settings
Effect of thermal annealing on the structure of LiCoO2 powders prepared by co-precipitation method
(2021-12-01)
Khejonrak, Awadol
;
Chanlek, Narong
;
Sukkha, Usa
;
Triamnak, Narit
;
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.
1
Some of the metrics are blocked by your
consent settings
Preface
(2021-09-20)
Thammavintorn, Preecha
;
Limkaisang, Viroj
;
Charoenprakdee, Anek
;
Seetawan, Tosawat
;
Kimura, Kaoru
Some of the metrics are blocked by your
consent settings
Temperature dependent local structure of LiCoO2 determined by in-situ Co K-edge X-ray absorption fine structure (EXAFS)
(2020-10-01)
Ekwongsa, Chinawat
;
Rujirawat, Saroj
;
Butnoi, Pichitchai
;
Vittayakorn, Naratip
;
Suttapun, Manoon
Recently, lithium cobalt oxide (LiCoO<inf>2</inf>) has a great attention as active cathode material lithium ion batteries. In this work, LiCoO<inf>2</inf> powder was prepared by solid state reaction and co-precipitation method. The synthesis parameters and phase formation behavior were investigated in details via several techniques, including thermal analysis, X-ray diffraction (XRD) and scanning electron microscopy (SEM). A change in local structure depending on temperature around Co atoms was investigated using in-situ extended X-ray absorption fine structure (EXAFS). The temperature ranged between 300 °C and 700 °C under air condition was applied for this study.
Some of the metrics are blocked by your
consent settings
Synchrotron-based NEXAFS analysis of thermal-treated diamond-like carbon films
(2020-10-01)
Chunjaemsri, Thanun
;
Chanlek, Narong
;
Sukkha, Usa
;
Nakajima, Hideki
;
Rujirawat, Saroj
Diamond-like carbon (DLC) film properties are known to vary with important factors such as the ratio of sp3 to sp2 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 sp3/sp2 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.
2
Some of the metrics are blocked by your
consent settings
Structural, optical and electrical properties of the microcrystalline structure of (Ba1-xY2x/3)(Zr0.20Ti0.80)O3 ceramics
(2020-07-01)
Sumang, Rattiphorn
;
Thongmee, Navavan
;
Bongkarn, Theerachai
;
Prasertpalichat, Sasipohn
;
Kidkhunthod, Pinit
Yttrium (Y3+) doped barium zirconate titanate, (Ba<inf>1-x</inf>Y<inf>2x/3</inf>)(Zr<inf>0.20</inf>Ti<inf>0.80</inf>)O<inf>3</inf>; BYZT ceramics with varying x (0 = x ≤ 0.10) were prepared by the solid-state reaction method. These samples were analyzed by X-ray diffraction (XRD) and the XRD patterns were fitted using the Rietveld refinement. The local structural changes of the BYZT ceramics were investigated by synchrotron X-ray absorption spectroscopy. The results showed that an increase in the x content in the BYZT lattice structure significantly affected the phase transition behavior and the local structure around the Ti absorbing atoms, which corresponds with the phase transition from a tetragonal to a cubic structure. SEM images showed a uniform and highly dense microstructure with increasing x values. The optical band gap (E<inf>gap</inf>) values measured from the UV–visual diffuse reflectance spectra, showed a decrease from ~3.55 eV to ~2.90 eV with increasing values of x. The modified Curie-Weiss law showed that a normal ferroelectric phase transition is observed in the unmodified BZT ceramic and as the concentration of x increased, it induces diffuseness in the phase transition behavior. The largest dielectric constant (ε<inf>r</inf> = 13,200), the highest recoverable energy-storage density (W<inf>rec</inf> = 1.76 J/cm3) with an excellent energy storage efficiency (η = 91%) under a lower electric field of 50 kV/cm and lowest dielectric loss (tanδ = 0.01) were found in the composition of Ba<inf>0.98</inf>Y<inf>0.01337</inf>Zr<inf>0.2</inf>Ti<inf>0.8</inf>O<inf>3</inf> (x = 0.02 mol.%).
Some of the metrics are blocked by your
consent settings
Photoluminescence and X-ray photoelectron spectroscopic study of milled-ZnO material prepared by high energy ball milling technique
(2020-01-01)
Mekprasart, Wanichaya
;
Ravuri, Balaji R.
;
Yimnirun, Rattikorn
;
Pecharapa, Wisanu
Luminescence properties that are correlated to near band edge emission and defect-related emission of milled zinc oxide (ZnO) powder prepared by high energy ball milling technique are investigated. Commercial ZnO powder (particle size of 525 nm) was chosen as starting material in milling process to produce ultrafine ZnO powder. The milling process was carried out at different speeds; 0, 200, 400 and 600 rpm for 10 min. After milling at high speed, change in color of milled ZnO powder was clearly observed that could be due to the defects in ZnO structure induced by mechanical strain during milling process. Surface morphology of milled ZnO powder was monitored by field-emission scanning electron microscopy (FESEM). Element component and surface chemical states of the samples were analyzed by X-ray photoelectron spectroscopy (XPS). Optical property of milled samples was investigated by diffuse reflectance UV-Vis spectrometer. Meanwhile, room-temperature photoluminescence spectroscopy of the milled samples was performed. The milled ZnO particle size was distinctly decreased to ca. 200 nm affirmed by FESEM images. Photoluminescence (PL) spectra of milled ZnO sample showed two prominent emission bands; UV and visible region. Visible emission intensity increased with increasing milling speed that would be attributed to greater structural defects caused by high mechanical strain during milling process.
1
Some of the metrics are blocked by your
consent settings
Synthesis and characterization of CH3NH3PbI3 and CH3NH3PbI(3-x)Clx perovskite solar cell materials
(2019-11-18)
Kamonpha, Phitsamai
;
Padchasri, Jintara
;
Rujirawat, Saroj
;
Sukkha, Usa
;
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.
1

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results