bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis, Crystal Structures, Phase Transition Characterization and Thermal Properties of the (1–x)PbZrO3-xPb(Co1/3Nb2/3)O3 Solid Solution System
Authors: Banlue W. , Muanghlua R. , Vittayakorn Wanwilai C. , Vittayakorn Naratip
Published: March 2009

The phase transition behavior of the (1–x) PbZrO3-xPb(Co1/3Nb2/3)O3 (PZCN) solid solution system (0 ≤ x ≤ 0.30) has been investigated by X-ray diffraction and DSC. In the solid solution, for x ≤ 0.20, the transition shows a first-order phase transition behavior and its antiferroelectric (AFE) crystal structure is orthorhombic. The transition temperature gradually decreases with increased Co2+/Nb5+ concentration. On the composition range 0.20 ≤ x ≤ 0.30, a typical relaxor-like behavior is displayed. The low temperature crystal structure is pseudo-cubic in this composition range. With these data, the ferroelectric phase diagram between PZ and PCoN has been established.
Effects of Zr/Ti Ratio on the Structure and Ferroelectric Properties in PZT-PZN-PMN Ceramics near the Morphotropic Phase Boundary
Authors: Muanghlua R. , Niemchareon S. , Vittayakorn Wanwilai C. , Vittayakorn Naratip
Published: March 2009

The piezoelectric ceramics of Pb(ZrxTi1−x)O3 – Pb(Zn1/3Nb2/3)O3 – Pb(Mn1/3Nb2/3)O3; PZT-PZN-PMN with Zr/Ti ratios of 48/52, 50/50 and 52/48 were fabricated in order to investigate the effect of compositional modifications on the ferroelectric properties of PZT-PZN-PMN ceramics. The phase structure of ceramics sintered at 1,150°C was analyzed. Results show that the pure perovskite phase was in all ceramic specimens, and the phase structure of PZT-PZN-PMN piezoelectric ceramics transformed from tetragonal to rhombohedral, with the Zr/Ti ratios increased in the system. The PZT-PZN-PMN ceramics with a Zr/Ti ratio of 50/50 exhibited the most promising properties including high remanent polarization and low coercive field of 25.95 µC cm−2 and 12.5 kV cm−1, respectively. Furthermore, the transition temperature decreased when the Zr/Ti ratio increased in the system.
Fabrication of 0-3 Non-Lead Based Piezoceramic/Polymer Composites Using Suction Technique
Authors: Sareein Thanapong , Thamjaree Wandee , Nhuapeng Wim , Tunkasiri Tawee
Published: March 2009

In this research, 0-3 composites between non-lead based piezoceramic and polymer were fabricated using the suction technique. Bismuth sodium titanate (Bi0.5Na0.5TiO3:BNT) which prepared from conventional mixed oxide method was used as active phase whereas epoxy resin was used as matrix phase. The 50% volumetric fraction of BNT/epoxy resin can obtain from suction technique. The physical and piezoelectric properties of composites samples were examined. It can be found that density of composite samples were about 1.78 g/cm3. Moreover, the piezoelectric coefficient (d33) of sample was 13 pC/N. Furthermore, the microstructure of composites was determined using SEM technique.
Microstructures of Zirconium Titanate Powders and Ceramics Prepared by Solid-State Mixed Oxide Method
Authors: Puchmark C. , Tipparak P.
Published: March 2009

Zirconium titanate (ZrTiO4): ZT powders were prepared by solid-state mixed oxide method. The mixed powder was calcined at various temperatures for 3 h ranging from 1100 to 1400 oC with a heating rate of 5 oC/min. X-ray diffraction analysis of the powders was performed using a diffractometer with Cu Ka. Pyrochlore phase was observed for calcinations below 1300 oC. In general, the strongest reflections apparent in patterns could be matched with a JCPDS file number 74-1504. The optimum calcination temperature for the formation of ZrTiO4 phase was found to be about 1300 oC for 3 h with heating rate of 5 oC/min. The microstructures of calcined powders were examined using scanning electron microscope (SEM). The particle size of powder increased with increasing calcination temperature. The ZT ceramics sintered at 1450, 1500, 1550 and 1600 oC for 4 h with heating rate of 5 oC/min, were checked for phase formation by X-ray diffraction. The density of sintered samples was measured by Archimedes method. The microstructures of sintered samples were examined using scanning electron microscope (SEM). The average grain sizes were checked by linear interception method. It was found that, the samples sintered at 1450 and 1500 oC gave rise to high purity ZT ceramics and the peaks matched well with ZrTiO4 phase in a JCPDS file number 74-1504. Unknown phases were found in ZT ceramics sintered at 1550 and 1600 oC. The value of density was in the range of 4.32 - 4.92 g/cm3 or 84.26 - 96.12 % of the ZT theoretical density. The densification of ZT ceramics decreased with increasing sintering temperature. The ZT ceramics sintered at 1450 and 1500 oC showed the average grain size of 8.55 and 12.55 µm, respectively. At sintering temperature 1550 and 1600 oC, morphology of grains changed to plate like crystals of second phases.
Preparation and Properties of B2O3-Doped Ba(Zr0.07Ti0.93)O3 Ceramics
Authors: Jarupoom P. , Rujijanagul Gobwute , Pengpat Kamonpan , Tunkasiri Tawee
Published: March 2009

In this work, barium zirconate titanate (Ba(Zr0.07Ti0.93)O3) ferroelectric ceramics doped with B2O3 were prepared by the conventional mixed-oxide method. The properties of the ceramics as a function of sintering temperature were investigated. Various technique such as X-ray diffraction (XRD) technique, scanning electron microscopy, dielectric permittivity spectroscopy and ferroelectric property measurement were used to obtain characteristic of the ceramics. The optimum density was observed for 1250 oC sintered sample. An increase in sintering temperature produced a decrease in dielectric constant. However, ferroelectric behavior was improved in 1275 oC sintered sample. The results were discussed in term of microstructure and crystallinity of the ceramics.
X-Ray Absorption Spectroscopy Study of Ba1-xSrxTiO3 (x = 0.0-0.2) at the Ti-K and Ba-LIII Edges
Authors: Somphon W. , Srilomsak Suthum
Published: March 2009

Barium titanate, BaTiO3 is a significant material for electronic components. It was known that Sr2+ substitution on Ba ion can strongly modify ferroelectric properties of BaTiO3 but the structural change has not been fully understood. An X-ray absorption spectroscopy at the Ti K-edge (4966 eV) and the Ba LIII-edge (5247 eV) was employed to investigate the structure of Ba1-xSrxTiO3 (BSTO) with 0<x<0.20. Results suggested that Ba2+ did not change its position with Sr2+ substitution. On the other hand, Ti4+ atoms gradually displaced as Sr2+ is increased.
Preparation of Barium Strontium Titanate Ceramics via Combustion Method
Authors: Bongkarn Theerachai , Wicheanrat C.
Published: March 2009

This study concentrated on the crystal structure and microstructure of [(Ba0.75Sr0.25)TiO3; (BST)] ceramics at different firing temperatures. The BST powders were prepared by a combustion method. (CO(NH2)2) was used as a fuel. Crystallinity of the calcined powders was improved by increasing the calcining temperature, as indicated by the increase in intensity of the X-ray diffraction peak. The pure perovskite phase of BST powders was obtained with a calcinations condition of 1200 oC. The a axis lattice constant of BST calcined powders and sintered ceramics were calculated and it was found that the crystal structure is a cubic phase. The microstructure of BST calcined powders and sintered ceramics were analyzed by a scanning electron microscope (SEM). The SEM result indicated that the average particle size and average grain size increased with the increase of calcinations and sintering temperatures, respectively. The apparent density of the samples was measured by the Archimedes method.
Fabrication of Lead Barium Titanate Ceramics via Conventional Solid-State Mixed Oxide Technique
Authors: Bongkarn Theerachai , Panya P.
Published: March 2009

(Pb0.925Ba0.075)TiO3 (PBT) ceramics have been prepared using a mixed oxide technique. The phase formation and morphology were studied in detail via X-ray diffraction (XRD) and scanning electron microscopy (SEM). The pure tetragonal perovskite structure was discovered with calcination temperatures above 800 oC. The percentage of perovskite phase and particle size tends to increase with the increasing of calcination temperatures. The PBT ceramics sintered at various temperatures belonged to a pure tetragonal perovskite phase. The average grain sizes increased from 0.90 to 6.44 µm with the increase of sintering temperatures from 1100 to 1200 oC. The highest density was obtained from the sample that sintered at 1150 and 1200 oC
Antiferroelectric Lead Zirconate Ceramics with Nanoparticle Alumina Additions
Authors: Puchmark C. , Milne S.J. , Rujijanagul Gobwute
Published: March 2009

The effects of alumina nanoparticles on the properties of PbZrO3 ceramics were investigated. The samples were prepared by a simple conventional mixed oxide method involving calcination and sintering temperatures of 800 oC and 1200 oC, respectively. Single-phase lead zirconate was observed in X-ray powder diffraction patterns for all the samples. The relationship between the Al2O3 content, the dielectric properties and Knoop hardness were determined. The results indicate that the additive affects Curie temperatures and the shape of the Curie peak, implying a chemical reaction takes place with the matrix during high-temperature processing. Hardness values increase for additions up to 1 vol % Al2O3.
Morphotropic Phase Boundary of Lead-Free Piezoelectric Ceramics from BNT- KN System
Authors: Pisitpipathsin N. , Koontasing W. , Eitssayeam Sukum , Intatha Uraiwan , Rujijanagul Gobwute , Pengpat Kamonpan , Tunkasiri Tawee
Published: March 2009

In this research work, the investigation of the morphotropic phase boundary, physical properties and electrical properties of lead- free piezoelectric materials of bismuth sodium titanium oxide: (Bi0.5Na0.5)TiO3 (BNT) and potassium niobium oxide : KNbO3 (KN) in the ceramic system of (1-x)BNT- xKN where x= 0.00, 0.03, 0.05, 0.08, 0.10 and 0.15 by modified mixed oxide method was carried out. The BNT and KN powders were prepared separately using calcination technique with optimum calcination temperature for producing both BNT and KN powders of about 800°C. XRD results revealed that the BNT-KN ceramics with low KN content of x less than 0.05 contain ferroelectric perovskite phase with rhombohedral symmetries while the higher KN content ceramics have mixed symmetries between rhombohedral and orthorhombic. From the evidences including phases, microstructures and dielectric data of the BNT-KN ceramics, it may be assumed that the morphotropic phase boundary may be at around the composition of x = 0.05.
Effect of Calcination Conditions on Phase Formation and Characterization of BiFeO3-BaTiO3 Powders Synthesized by a Solid-State Reaction
Authors: Chandarak S. , Sareein Thanapong , Ngamjarurojana Athipong , Maensiri S. , Laoratanakul Pitak , Ananta Supon , Yimnirun Rattikorn
Published: March 2009

A perovskite-type phase of solid solution of BiFeO3-BaTiO3 powders were synthesized by a solid-state reaction via a rapid vibro-milling technique. The effect of calcination condition on the phase formation, and characterization of BiFeO3-BaTiO3 powders were investigated. The formation of the BiFeO3-BaTiO3 phase investigated as a function of calcination conditions by TG–DTA and XRD. Morphology, particle size and chemical composition have been determined via a combination of SEM and EDX techniques and vibrating sample magnetometer (VSM) was used to characterize the structures and magnetic properties of prepared samples. The rapid vibro-milling is employed for the first time in this work as a significant time-saving method to obtain single-phase BiFeO3-BaTiO3 powders.
Changes in Ferroelectric Properties of 0.7PMN–0.3PT Ceramic with Compressive Stress
Authors: Unruan Muangjai , Wongmaneerung R. , Laosiritaworn Yongyut , Ananta Supon , Yimnirun Rattikorn
Published: March 2009

In this work, effects of compressive stress on the ferroelectric properties of 0.7PMN–0.3PT ceramics were investigated. The ceramics with the formula (0.7)Pb(Mg1/3Nb2/3)O3-(0.3)PbTiO were prepared by a conventional mixed-oxide method. The ferroelectric properties under compressive stress were observed at stress up to 80 MPa using a compressometer in conjunction with a modified Sawyer-Tower circuit. The results showed that applied stress had a significant influence on the ferroelectric properties of 0.7PMN–0.3PT ceramics. Ferroelectric characteristics, i.e. the area of the ferroelectric hysteresis (P-E) loop, the saturation polarization (Psat), the remanent polarization (Pr) and loop squareness (Rsq), decreased with increasing compressive stress, while the coercive field (Ec) remained relatively constant. Stress-induced domain wall motion suppression and non-180oC ferroelectric domain switching processes are responsible for the changes observed.
Scaling Behavior of Dynamic Hysteresis in Hard PZT Bulk Ceramics under Influence of Compressive Stress
Authors: Wongdamnern N. , Ngamjarurojana Athipong , Ananta Supon , Laosiritaworn Yongyut , Yimnirun Rattikorn
Published: March 2009

Effects of electric field-amplitude and mechanical stress on hysteresis area were investigated in partially depoled hard PZT bulk ceramic. At any compressive stress, the hysteresis area was found to depend on the field-amplitude with a same set of exponents to the power-law scaling. Consequently, inclusion of compressive stresses into the power-law was also obtained in the form of < A – Aσ=0 > α E05.1σ1.19 which indicated the difference of the energy dissipation between the under-stress and stress-free conditions.
Spectroscopys Studies of Iron Phthalocyanine Thin Films
Authors: Chamlek Onanong , Pratontep S. , Kerdcharoen Teerakiat , Osotchan Tanakorn
Published: March 2009

Iron phthalocyanine (FePc) thin films prepared by thermally evaporated from as received and purified powders were studied. The molecular interaction between FePc thin films and acetone vapor was studies by X-ray photoemission spectroscopy (XPS) and optical absorption spectrometer. The core level XPS spectra and optical absorption spectra showed slightly different between the spectra before and after acetone exposure. For FePc film evaporated with purified powder, only the Fe 2p3/2 spectra at about 712 eV appeared and the height of peak dramatically decreased. Iron K-edge X-ray absorption near edge structure (XANES) spectra was used to investigate iron atom in as received and purified powders and also study the interaction between FePc molecule and methanol vapor. The X-ray diffraction pattern of as received, annealed and purified FePc powder were investigated to study the crystal reformation and Raman spectroscopy was used to investigate iron atom vibration in as received FePc film.
Influence of ZnO Content on Film Morphology and Device Performance of MEH-PPV/ZnO Hybrid Solar Cells
Authors: Kasemsuwan K. , Suvewong T. , Pavarajarn V. , Thanachayanont Chanchana
Published: March 2009

Hybrid solar cells based on conjugated polymer poly(2-methoxy,5-(2’-ethylhexyloxy)-p-phenylene vinylene (MEH-PPV) and inorganic n-type zinc oxide (ZnO) nanoparticles were investigated. Polymer solar cells consisting of conducting polymer alone have low minority carrier mobility, for example, MEH-PPV has a high hole mobility but a low electron mobility. The intrinsic carrier mobility imbalance in the MEH-PPV severely limits the performance of pure polymer based solar cells. To overcome this imbalance, another material, i.e. n-type ZnO particles, is incorporated to act as an electron acceptor and a pathway for electron transport. In this experiment, as an active layer, ZnO nanoparticles synthesized in-house were blended with MEH-PPV purchased from Sigma-Aldrich. The front transparent conduction oxide (TCO) electrode used was commercial glass substrate coated with indium tin oxide (ITO) thin film. Blends of MEH-PPV with 0-30 wt% of ZnO in 1,2-dichlorobenzene were prepared and fabricated as active layers of the solar cells. The PEDOT:PSS and active layer were spin-coated onto ITO coated glass substrate. Aluminum was used for the top electrodes. The effects of ZnO solid content and film morphology on the performance of MEH-PPV:ZnO nanoparticle composite solar cells were investigated. Transmission electron microscopy (TEM) revealed that the ZnO nanoparticles consisted of a mixture of spherical and rod-like shapes. An increase in ZnO solid content resulted in an increase in size of the ZnO network. This was found to increase electron transport and, hence, improve solar cell performance.
Defining Structure in Electrospun Polymer Fibres
Authors: Mitchell G.R. , Belal M. , Davis F.J. , Elliott D.E. , Kariduraganavar M. , Mohan S.D. , Olley R.H. , Sen Sujat
Published: March 2009

We use a combination of microscopy, x-ray scattering and neutron scattering to show how structure develops in micro and nano-size polymer fibres prepared by electrospinning. The technique has been applied to a range of different polymers, an amorphous system (polystyrene), a crystallisable polymer (poly-ε-caprolactone), a composite systems (polyethylene oxide or poly vinyl alcohol containing polypyrrole) and consider the possibility of self assembly (gelatin).
Thermal Stabilization of PVC Using Organic Modified Montmorillonite
Authors: Thongpin Chanchai , Tangchantra N. , Kositchaiyong Apisit , Sagnuanmoo R. , Jantham J. , Sooksa-ard A.
Published: March 2009

There has been a number of works trying to improve thermal stability of PVC as it is one of the most widely used plastics for various applications. The incorporation of heat stabilizer is a general method to stabilize PVC. However, its thermal stability could also be improved by blending with polyethylene. Organoclay, montmorillonite (MMT) in particular, has been found to improve thermal stability of polymers due to its high temperature resistance. This research is aimed to use organic modified MMT (OMMT) to improve thermal property of PVC. It was found from the research that organic grafted MMT (O-g-MMT) could improve thermal stability of PVC better than OMMT. The mechanical properties of O-g-MMT/PVC and OMMT/PVC of the blends were also reported
Thermal Conductivity of Ceramic Fibres at High-Temperatures
Authors: Anis-ur-Rehman M.
Published: March 2009

Three ceramic ﬁbres VK-60, ABK and Nextel/VK-80 produced by the steam blowing and nozzle dissemination methods have been investigated for the effect of press load per unit area and temperatures using the advantageous transient plane source (ATPS) method in air. It was noticed that, with the increase of the aluminium content in the composition of the ceramic ﬁbres, the thermal conductivity of the material decreases and the isolation properties improved. The Nextel/VK-80 ﬁbre has the lowest and VK-60 the highest value of thermal conductivity at room temperature. The application of a press load results in an increase in the value of the thermal conductivity for all the ﬁbres analysed. ABK ﬁbres showed the least increase and Nextel/VK-80 registered an increase of about 10% in the value of thermal conductivity within the load increase from 0.6 to 6.6 kN m−2. However, above 6.6 kN m−2 the thermal conductivity of all the samples increased almost linearly. The thermal conductivity measurements as a function of temperature indicated the same trend for an increase in thermal conductivity for all the samples.
Effect of Polarization on the Microstructure and Piezoelectric Properties of PZT-Cement Composites
Authors: Chaipanich Arnon , Jaitanong Nittaya
Published: March 2009

Lead zirconate titanate (PZT)-Portland cement (PC) composites were produced and successfully poled at different poling field and time. The effect of polarization on the microstructure and piezoelectric properties were then investigated. It was found that, at a fixed poling field up to 2 kV/mm, the piezoelectric coefficient (d33) was found to increase with poling time. The optimum poling time was found at 45 minutes where d33 value is 42 pC/N. The optimum and most practical poling field found for the composite was at 2 kV/mm. Lower poling field would give the composite lower piezoelectricity and poling field that is too high would result to breakdown of samples. Therefore, from these results, a poling field of 2 kV/mm at 45 minutes would be the ideal polarization condition used in poling PZT-PC composites.
The Effects of Thermal Consolidation Methods on PET Nonwoven Composites for Thermal Insulation Use
Authors: Lou Ching Wen , Lin Ching Wen , Lin Chia Chang , Li S.J. , Tsai I.J. , Lin Jia Horng
Published: March 2009

As available energy sources have grown increasingly scarce, people have started paying attention to their energy consumption. Although many methods for power generation are being actively investigated, efficient methods for solving energy problems must be based on reducing energy consumption. Thermal insulation can decrease heat energy loss and conserve energy waste, especially in the construction, transportation and industrial fields. In this study, polyester (PET) hollow fibers were blended with various ratios of low-melting-point PET fibers (10%, 20%, 30%, 40% and 50%). The fibers were blended using opening, carding, laying and needle punching (150 needles/cm2, 225 needles/cm2 and 300 needles/cm2) to prepare PET nonwoven fabrics. The PET nonwoven fabrics were thermally plate pressed (TPP) and air-through bonding (ATB). Thermal conductivity, physical properties and air permeability were investigated to identify the influence of manufacturing parameters on the PET nonwoven fabrics. The experimental results show that needle punching density, TPP and ATB would influence the thermal conductivity of PET nonwoven fabric, because the structure of PET nonwoven fabric was changed. The optimal parameters of PET nonwoven fabric clipped with an aluminum foil was used to evaluate the influence of aluminum foil on thermal conductivity. The PET nonwoven composite in this study can be used in industrial thermal insulation applications.
Effectively Doping of Rare Earth Additives in Sol Gel Derived PZT Ceramics
Authors: Asl S.K. , Asl S.K.
Published: March 2009

The PZT-based ceramics with a composition of Pb1.1-sRs (Zr0.53Ti0.47)O3.1+0.5s; s = 0.00 – 0.02, R= La, Nd, Sm were prepared by conventional mixed-oxide, and sol-gel methods, with optimal preparation conditions. The microstructural and electrical properties were examined as a function of the additive content and type then compared. Microstructural and compositional analyses of the PZT-based ceramics have been carried out using SEM and XRD. Dielectric properties of the samples were measured with an impedance analyzer. The ferroelectric properties of the PRZT samples were measured using the frequencies. It showed that the La additive improved both the dielectric and piezoelectric properties. Using sol gel method decreased saturation point of PZT. The PRZT with 0.5 mol% La be in optimum condition
Fabrication of Double Layers of Aramid Fiber/Alumina/Epoxy Resin Laminate Composite Using Low-Pressure Technique
Authors: Nhuapeng Wim , Kumfu Supreyak , Thamjaree Wandee , Tunkasiri Tawee
Published: March 2009

An experimental investigation was carried out to study the fabrication of double layers of aramid fiber/alumina/epoxy resin laminate composites using low-pressure technique. To obtain the sample with high wear resistance property, the micron size of alumina particles were added into epoxy resin using the ultrasonic processor. The physical and mechanical properties such as density, hardness, impact test, wear resistance and tensile strength of the composites samples were investigated. Furthermore, microstructures of specimens were also examined by scanning electron microscope (SEM). From the results, it was found that the mechanical properties of double layers laminate composites of aramid fiber/alumina/epoxy resin could improve by using the low-pressure technique.
Ferroelectric Glass-Ceramics from the PbO-Bi2O3-GeO2 System
Authors: Munpakdee A. , Pengpat Kamonpan , Tunkasiri Tawee , Holland D.
Published: March 2009

he glass ceramics from the PbO-Bi3O2-GeO2 system have been investigated. An excellent transparent glass can be obtained from the stoichiometric (S) composition, Pb3Bi2(GeO4)3, but only by rapid-quenching to give very thin samples. This glass could not therefore be used to make good glass-ceramic samples for measuring the dielectric properties. The A-composition (34.50%PbO :11.49%Bi2O3: 54.01%GeO2) and B-composition (25.90%PbO: 8.63%Bi2O3: 65.47%GeO2) have been prepared to form more stable glasses. These two compositions gave good transparent and thick glass samples. DTA analysis has been used to examine the crystallisation temperatures of all glasses. The controlled heat treatment process has been applied to all crystallisation temperatures and glass-ceramic samples were obtained. It was found that S glass-ceramic contained Pb3Bi2(GeO4)3 and Bi2GeO5 while A glass-ceramic contained only Pb3Bi2(GeO4)3 and was suitable for using in dielectric measurement. B glass-ceramic gave difficulty in identifying the phases. However, it was concluded that the glass-ceramic from this composition had three phases, which are PbGe4O9, PbGeO5 and Bi4(GeO4)3. Since this glass gave no PbO-Bi2O3-GeO2 ternary phase, the dielectric measurement concentrates only on the A glass-ceramic. The frequency dependence of eeee²²²² for the A glass-ceramic sample gave a loss peak at low frequency.
Packet Switching Start-Stop Bits Generation Based on Bifurcation Behavior of Light in a Micro Ring Resonator
Authors: Pornsuwancharoen N. , Kumbun J. , Yupapin P. Preecha
Published: March 2009

his paper proposes the interesting nonlinear behavior of light known as bifurcation, where the use of such behavior in a micro ring resonator to form the secure digital codes for optical packet switching application is demonstrated. A new concept of the stop-start bits in an optical packet switching protocol is formed by using the bifurcation codes. The bifurcation is introduced when light is input into a nonlinear micro ring device, where the refractive index of an InGaAsP/InP is one of device parameters. The other parameters of the device are coupling coefficient (K) and the ring radius (R), where the ring radii used are ranged from 5-10 microns. Simulation results obtained have shown that the packet switching data can be secured by using the generated start-stop bits as the secured codes.
Phase Evolution and Physical Properties of (1-x)BZT-xBFN Ceramic System
Authors: Maimon H. , Eitssayeam Sukum , Intatha Uraiwan , Tunkasiri Tawee , Satittada G.
Published: March 2009

Phase evolution and physical properties of (1-x)BZT–xBFN ceramic system were investigated to find the optimum condition for electronic applications. (1-x)BZT–xBFN powders were prepared by solid state reaction technique varying x from 0.2 to 0.8 and various sintering temperatures from 1350 °C to 1450 °C. Phase formation was investigated by X-ray diffraction technique. The XRD analysis demonstrated that with increasing BFN content in (1−x)BZT–xBFN, the structural change occurred from the tetragonal to the cubic phase at room temperature. Changes in the physical and mechanical properties were then related to this structural transformation depending on the BFN content.
Optimization of Chemical Vapor Deposition Synthesis Conditions for Multiwall Carbon Nanotube by Statistical Analysis of Experiment
Authors: Saiprasert P. , Koolpiruck D. , Chiangga S.
Published: March 2009

The optimization of chemical vapor deposition synthesis conditions for multiwall carbon nanotubes (MWCNTs) was experimentally investigated. Carbon nanotubes were grown on cobalt substrate thicknesses of 20, 100 and 1000 nm at 700 and 900 0C with 2 replications. The configuration and morphology of the carbon nanotubes were investigated by scanning electron microscope and Fourier transform raman spectrometer, respectively. The tendency of the parameters was evaluated by statistical design of experiment. Observations on samples produced under our optimised production process, showed that a large number of MWCNTs bundles were produced. Diameter of MWCNTs bundles ranges between 30 and 100 nm throughout the samples. From the variance analysis of the Raman spectra we observe that the thickness of cobalt and temperature of synthesis are highly significant in which the coherence length and innermost diameter increase for either the thickness increases or the temperature decreases.
Attachment of Metal Oxide Nanoparticles on Carbon Nanotubes with Different Oxidation Levels
Authors: Hsieh Chien Te , Lin J.Y.
Published: March 2009

An efficient surface modification technique for fabricating tin dioxide/carbon composite nanotubes has been developed. This technique combines with implantation of acidic groups, interaction between surface oxides and metal ions or hydration molecules, and thermal. To functionalize multi-layered carbon nanotubes (CNTs), gaseous oxidation at 300°C was used to build functional oxygen groups including carboxyl, carbonyl and hydroxyl group, on ends or sidewalls of CNTs. X-ray photoelectron spectroscopy clearly indicated that the atomic ratio of attached tin-oxide on the oxidized CNTs gradually increases with the oxidation level, i.e., surface O/C atomic ratio. This evidence reflected that the surface oxides act as an adsorption center that strongly interacts with metal ions or hydration molecules in aqueous phase.
Growth Conditions for Carbon Nanotubes and Helical Nanofibers on Copper Substrates Using Sparked Catalysts
Authors: Toboonsung B. , Singjai Pisith
Published: March 2009

Carbon nanotubes (CNTs) and helical nanofibers (HNFs) were selectively grown on copper substrates by chemical vapor deposition using acetylene as a carbon source. The experiments were carried out by using Ni, Fe and Co as single and co-catalysts which were deposited onto the substrates by a sparking method. The catalyst-coated copper substrates were heated at 750°C in a mixed-gas-flowing tube furnace, at an argon flow rate of 100 ml/min and various acetylene flow rates of 3, 5 and 10 ml/min. The larger diameter of HNFs was grown only on Ni and Ni-Fe catalysts at the acetylene flow rates of 5 and 10 ml/min whereas the uniform smaller diameter of CNTs was preferentially grown on Fe-Co and Ni-Fe catalysts at the flow rate of 3 ml/min. We suggest that Co likely prevents the formation of HNFs whereas Ni promotes.
Oxygen Control on Nanocrystal-AlON Films by Reactive Gas-Timing Technique R.F. Magnetron Sputtering and Annealing Effect
Authors: Bunjongpru Win , Porntheeraphat S. , Somwang N. , Khomdet P. , Hruanun C. , Poyai Amporn , Nukeaw J.
Published: March 2009

The AlON films grown on Si(100) substrates by using radio frequency (r.f.) magnetron sputtering from high purity aluminum (99.999% Al) target with a novel reactive gas-timing technique. The 100 nm thick of AlON films were deposited with 200 watts r.f. power and the substrate temperature is maintained at room temperature by the technique of gas-timing which varying flow-in sequence of high purity of Ar (99.999%) and N2 (99.9999%) gases fed into the sputtering chamber at 10:90 (sec) ratio. The composition and crystal orientation of AlON films affected by gas-timing of Ar and N2 were analyzed by Auger Electron Spectroscopy (AES) and X-ray diffraction (XRD). The oxygen atoms revealed by AES formed into a corporation in films was studied. This suggests that the oxygen contamination formed as AlOXNY compound may due to the residual oxygen in base pressure of 10-7 mbar and higher reactivity of oxygen in the reactor compared to nitrogen. The gas-timing technique used in the sputtering growth system shows the advantage of the oxygen quantity control, while the general sputtering process (without gas-timing technique) shows an increase of the oxygen composition depended on film thickness. The characterizations results clearly indicate that the gas-timing r.f. magnetron sputtering technique plays an important role to control the incorporation of oxygen and to form the nanocrystal-aluminum oxynitride films which very attractive for various sensors applications.
Fabrication of Zirconia Nanofibers Using Zirconatrane Synthesized by Oxide One-Pot Process as Precursor
Authors: Panapoy M. , Ksapabutr Bussarin
Published: March 2009

Zirconia nanofibers were fabricated from alcoholic solution containing zirconatrane and poly(vinyl pyrrolidone) (PVP) using electrospinning and sol-gel process with subsequent calcination process. A low-cost and facile route to synthesize zirconatrane complex, which can be further employed as alkoxide precursor for zirconia or doped zirconia via sol-gel technique, has been developed from the reaction of a very inexpensive and plentiful starting materials via the oxide one-pot synthesis (OOPS) process. Zirconatrane complex was directly synthesized from zirconium hydroxide, triethanolamine and ethylene glycol. The structure of resultant products was fully characterized using FTIR, 1H, 13C-NMR, elemental analysis (EA), and mass spectroscopy (MS). The PVP/zirconia composite nanofibers were electrospun and calcined at different temperatures. The as-electrospun and heat-treated PVP/zirconia composite nanofibers were characterized using TGA, XRD and SEM. After calcination of the as-spun composite fibers at 600oC for 5 h, zirconia nanofibers of about 190 nm in diameter having tetragonal structure were obtained. Increasing the calcination temperature resulted in the formation of zirconia fibers with ribbon-like morphology having an average width of 600 nm and thickness of 140 nm.
Synthesis of Conducting Polymer Films by Plasma Polymerization Process
Authors: Bhanthumnavin Worawan , Kamphiranon Phensupa , Paosawatyanyong Boonchoat
Published: March 2009

A microwave (MW) plasma reactor for the synthesis of polythiophene (PTh) thin films as well as in situ doping during polymerization process has been designed and assembled. Plasma polymerization parameters were studied. A good MW power was found to be in the range of 150-250W. PTh films were characterized by various spectrophotometric methods. IR analyses showed absorption frequencies of important functional groups. PTh films exhibited UV-Vis spectra indicative of increased conjugative systems as the MW power increased although at 300 and 380W partial fragmentation was evident. Surface analysis by SEM revealed a uniformly deposited film morphology. EDS results were also suggestive of partial fragmentation of the films at high MW powers. Preliminary conductive measurements revealed that the undoped films exhibit higher conductivity (3 to 9×10-5 s.cm-1) than PTh typically prepared from electrochemical methods.
Electrical Properties and Microstructures of P2O5-CaO-Na2O Glasses
Authors: Raengthon N. , Pengpat Kamonpan , Tunkasiri Tawee
Published: March 2009

In various types of biomaterials used worldwide today, bioglass is one of the most interesting and a useful choice for research as it is unharmful or nontoxic to biological tissue. Binary or ternary phosphate-based glasses are also good candidates to be improved and used effectively. Glasses with 40 – 60 mol% of P2O5 incorporated at a constant mole-ratio of CaO: Na2O are studied in this experiment. Each batch of glasses is melted in an electric furnace at a temperature of about 1000 °C and splat-quenched at room temperature. Electrical properties such as conductivity and dielectric constant and microstructures of these glasses were investigated.
Characterization and Thermal Properties of Sol-Gel Processed PMMA/SiO2 Hybrid Materials
Authors: Buasri A. , Liangraksa K. , Sirisom T. , Tangkachalakul N.
Published: March 2009

Hybrid organic-inorganic materials were fabricated using sol-gel technique using poly(methyl methacrylate) and methacrylic acid 3-(trimethoxysilyl)propyl ester (MAMSE) with 90/10, 80/20 and 70/30 (%w/w) ratios with tetrahydrofuran (THF) solvent. The thin films were then characterized using FTIR spectra, SEM, DSC and TGA thermograms. From the preliminary characterization, the hybrid material was found to have nano and ultra scale tight pore ranges. FT-IR spectroscopy uncovered all the signature peaks characteristic of silicate structures in the near-surface regions. Fingerprints of Si-O-Si groups in cyclic and linear molecular substructures are present. The SEM image clearly shows that hybrid materials have homogenous and smooth surface. DSC analysis of the material shows interesting phenomenon regarding glass transition temperature (Tg). The hybrid material was found to have higher Tg than pure PMMA. From TGA analysis, the hybrid materials were observed to have higher thermal stability than pure PMMA.
Preparation and Properties Indium Tin-Oxide Thin Films by RF Sputtered for Photodetectors
Authors: Srithanachai I , Nutaman K. , Rerkratn A. , Niemcharoen S. , Supadech S.
Published: March 2009

This paper descript studying and preparation indium-tin oxide (ITO) thin film from method 90 wt.% In2O3 and 10 wt.% SnO2 formula target with 99.99% purity on glass slide by RF reactive sputtering method at room temperature. This paper, sputtering time 5, 15, 30 and 60 mins. Thin films ITO were measured crystallization, optical and electrical characteristic by an X-ray diffractometer (XRD), scan electron microscopy (SEM) , Four Point Probe and UV-VIS spectrophotometry. The results found that thin films which made from RF sputtering method had a high crystallization, order arrangement grain. Strong peak of XRD (400) and (441), low resistivity are 2.2 x 10-3, 4.4 x 10-3, 1 x 10-3 and 7 x 10-4 Ω-cm, transmittance are 82%, 84%, 87% and 89%, respectively. The overall experimental results identify that fabricated thin films ITO have good properties and is suitable for transparent electrode application. The ultimate goal is developing schottky photodetector.
Computational Study on Thermodynamic and Structural Properties of ZSM-5 Doped by Al/Fe and Al/P
Authors: Pongsai S.B. , Hannongbua S.
Published: March 2009

Configurational averaging technique is adopted via lattice statics approach to obtain the thermodynamic and structural properties of ZSM-5 containing various impurity content. Different Si:Al:Fe and Si:Al:P ratios within o-ZSM-5 and m-ZSM-5 frameworks have been studied. The results show that the third type of atom (Fe or P) incorporated to aluminosilicate ZSM-5 plays an important role on the structural stability of zeolite. It is indicated that the lattice enthalpy of aluminosilicate ZSM-5 is highered when doping with Fe, but it is lowered when doping with P. It is found that for o-ZSM-5 doped by Al/Fe and Al/P, the values of  bond lengths, as well as  and  bond angles, are close to those for siliceous o-ZSM-5. However, for m-ZSM-5 doped by Al/Fe and Al/P, the values of  are slightly longer whereas  and  are smaller compared with those for siliceous m-ZSM-5.
Sintering Behavior of the β"-Alumina Solid Electrolyte for Battery Applications
Authors: Niyompan Anuson , Srisurat Kanita , Tipakontitikul Rungnapa , Pengpat Kamonpan , Tunkasiri Tawee
Published: March 2009

The β″-alumina solid electrolyte proposed for the application in the electric vehicle battery system was prepared via a liquid phase sintering method. The main aim of the study is to reduce sintering temperature which is normally required as high as 1700oC. The MgO-stabilized Naβ″-alumina with the composition Na1-xMg2xAl5-xO8 where x = 0.125 was prepared. The mixture of Na2CO3, MgO and γ -Al2O3 were produced and well-mixed by wet ball milling method. Then, calcination was performed at 1200oC for 10 h. Calcined β″-alumina was then added with a sintering aid, CuO, at several concentrations prior to forming by a dry pressing technique. The green pellets were then sintered at different temperatures with constant dwell time for 4 h. Phase identification on calcined powders indicate that β″-alumina present as a mojor phase co-existed with tiny proportion of β′-alumina. Co-existence of these two phases is commonly found for this particular system. Phase checking for sintered samples with CuO additive show no phase change but concentration ratio of the β′-alumina seem to increase with increasing sintering temperature and mol% of the CuO. Sintering at 1550oC, the higher densification is clearly observed for ceramic with higher CuO content, i.e. 5 and 10 mol%. Layered-structure of the β″-alumina can be clearly seen from the SEM micrographs. The SEM results also show that higher CuO content promoted a higher grain development and produced less porosity. Dc conductivity values of the samples with CuO adding are reasonable high comparing to that of without CuO adding. This study has been show that β″-alumina produced by liquid phase sintering here is considerably appropriate to the application in the battery of electric vehicles.
Defect-Induced Properties of Doped Alpha Alumina Samples
Authors: Jantaratana P. , Dararutana Pisutti , Wongkokua Wiwat , Pongkrapan Sorapong , Wathanakul P.
Published: March 2009

The dielectric constant values of a set of synthetic alpha alumina samples doped with Cr and Be were determined using parallel plate method. The voltage frequency was selected at 1 MHz. When Cr was doped to the sample, the dielectric constant was increased due to the increase in polarizations of the sample, whereas the Be-doped one showed the decrease in dielectric constant cf. the undoped synthetic alpha alumina (reference sample). Experiments on doping alpha alumina with both elements showed increasing in dielectric constant compared to the undoped reference sample, i.e., Cr has more influence to the dielectric constant value. Dielectric constants of a set of natural sapphires were also measured and compared to those obtained from the synthetic ones. The results of both natural and synthetic samples varied in the same direction. It suggests, however, that the geological origins of the samples are needed to be considered. This is due to the differences in physico-chemical conditions of their formations that would have influenced partitioning of trace elements as well as evolving of defects in natural samples. Increasing of the R1 and R2 photoluminescence wavelengths and decreasing of refractive indices of the doped samples cf. those of the reference sample were obtained from the experiments.
BaMnTiO3 Synthesized by the Oxalate and Impregnation Methods
Authors: Pookmanee Pusit , Ketwong P. , Phanichphant Sukon
Published: March 2009

Barium titanate (BaTiO3) was synthesized by the oxalate method with the starting precursors as barium chloride and potassium titanium oxalate with mole ratio of 1:1. Precipitate was obtained after adding oxalic acid until the pH of the final solution was 4. The precipitate was milled and calcined at 700 oC for 2h. Mn-doped barium titanate (BaMnTiO3) was prepared by the impregnation method. Barium titanate calcined at 700 oC was mixed with 2 and 4 mole % of Mn from manganese chloride. The mixed powder was calcined at temperatures of 800 oC and 900 oC for 2h. The phase of BaMnTiO3 was studied by X-ray diffraction (XRD). Hexagonal structure of Ba(Mn0.33Ti0.67)O2.84 was obtained after calcination at 900 oC for 2h with 2 and 4 mole % of Mn. The morphology and chemical composition were investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The particle size of Ba(Mn0.33Ti0.67)O2.84 powder was in the range of 50-60 nm with irregular in shape. The elemental composition of barium, manganese, titanium and oxygen showed the characteristic X-ray energy values.
Behaviour of Various Glass Seal for Planar Solid Oxide Fuel Cell
Authors: Punbusayakul N. , Wongklang W. , Wongtida K. , Charoensuk J. , Charojrochkul S.
Published: March 2009

One of the critical issues in designing a planar solid oxide fuel cell (SOFC) is the development of materials to hermetically seal the metal (430 series stainless steel) or ceramic interconnector with the ceramic electrolyte of the cell. The main objective of this sealing material is to achieve a low leak rate, long-term stability at operating temperature and chemical compatibility with other components. One of the compositions has been operated in an SOFC in excess of 30 minutes over the range of 600, 700, 800, and 900°C. The seal is a composition of polymer blend and glass of 1:3, 1:1 and 3:1 by weight. The leakage rate of each seal was measured simultaneously under the compressive force of 100 N, 2 bar Helium. The seal was characterized using a thermogravimetric analysis. The effect of glass composition on operating temperature and compressive forces on the leakage rate have been discussed and correlated.
Effect of Substrate-Surface Orientation on the N Incorporation in GaAsN Films on GaAs Grown by MOVPE
Authors: Klangtakai P. , Sanorpim S. , Kuboya S. , Katayama R. , Onabe Kentaro
Published: March 2009

The GaAs1-xNx alloy semiconductor has been grown on GaAs (001), (111)A and (011) substrates by metalorganic vapor-phase epitaxy. High resolution X-ray diffraction and Raman scattering were employed to examine the effective N content and the growth rate, as a function of the substrate-surface orientation. The growth rate, which was assessed though the clear Pendellösung fringes, and the N content were found to change dramatically with the substrate-surface orientations. The N content was determined in the order (111)A > (001) > (011). While, the growth rate is in the order, (001) > (011) > (111)A. The effect of substrate-surface orientation on the N incorporation found in the present study is interpreted in terms of the difference in the growth rate on each surface orientation and the number of dangling bonds with which the N atoms can be trapped on the growing surface. Our results show that controlled nitrogen incorporating for GaAsN is successfully achieved and can be applied to the fabrication of some novel structures such as a spontaneous N content modulated structure, which is applicable to high performance long wavelength laser diodes.
Lead-Free Ferroelectric Material: Dysprosium Doped Bi4Ti3O12
Authors: Thongmee N. , Watcharapasorn Anucha , Jiansirisomboon Sukanda
Published: March 2009

This study investigated fundamental of phase formation, crystal structure and calcination process for bismuth dysprosium titanate (Bi4-xDyxTi3O12; BDT) powders when x = 0, 0.25, 0.5, 0.75 and 1.0. BDT powders were prepared using a simple solid-state reaction on mixtures of reagent grade Bi2O3, Dy2O3 and TiO2 powders. The mixtures were calcined at temperature in the range of 500-800°C for 4 h at a heating/cooling rate of 5°C/min. Thermal characteristics of powders were studied using thermogravimetric/differential thermal analyses which indicated that the formation of Bi4Ti3O12 and Bi3Dy1Ti3O12 powders occurred at ~500oC. Effect of Dy3+ concentration on phase and crystal structure was investigated using X-ray diffractometry. The results revealed that at small concentration of Dy dopant (x £ 0.25), optimum calcination temperature for providing bismuth titanate-based phase was 650oC. Increasing content of Dy dopant seemed to reduce calcination temperature to 600oC. This study suggested the alternative environmental friendly BDT materials which may be used as starting powders for production of high quality BDT ceramics.
Cost Effective Natural Adsorbent for Fluoride Removal
Authors: Janta S. , Watanesk S. , Watanesk R. , Thiensem Sakdiphon
Published: March 2009

In this study, the uptake of fluoride by raw diatomite and diatomite activated by heat treatment was investigated. Influential parameters such as contact time, pH and adsorption isotherm were also studied. The results showed that the diatomite heated to 500 oC performed better than other heat treatment products and the equilibration time needed for fluoride removal by the adsorbents was reached at 60 min. Results revealed that the capacity of the adsorbents for removing fluoride is independent of the pH when the pH is higher than 4. The adsorption isotherm of the 500 oC treated diatomite showed its Langmuir behavior. The maximum adsorption capacity of raw diatomite and 500 oC calcinated diatomite are 2.253 and 4.162 mg/g, respectively. Based on the results it can be concluded that the diatomite appears to be an economical and environmentally friendly material for defluoridation of water.