bluuebunny/crossref_metadata_2025 huggingface dataset:
Water-Resistant Poly(Vinyl Alcohol) Hybrid Nanofibers Incorporating Polyhedral Oligosilsesquioxane (POSS)
Authors: Kim Byoung Suhk , Kang Hyo Kyoung , Khil Myung Seob , Kim Hak Yong , Kim Ick Soo
Published: January 2010

We have explored a straightforward approach for achieving water-resistant properties of the electrospun PVA nanofibers. The electrospun PVA nanofibers are post-treated with a hydrophobic polyhedral oligosilsesquioxane (POSS) hybrid macromer via a direct urethane reaction between the hydroxyl group of PVA and the isocyanate group of POSS macromers. The POSS-modified PVA nanofibers are characterized by fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and water resistant property. The morphologies of the electrospun PVA nanofibers before and after POSS post-treatments are regular and a narrow distribution of diameters was observed, indicating a uniform post-treatment of POSS macromers onto the PVA nanofibers. Thermal decomposition behavior of the POSS-modified PVA nanofibers was altered compared to the pure PVA nanofibers, suggesting the suppression of thermal decomposition due to the incorporation of POSS macromers. In addition, the pure PVA nanofiber mats immersed in pure water exhibited no characteristic morphology, whereas the POSS-modified PVA nanofiber mats showed the texture morphology, indicating an enhanced water-resistant property.
Through Thickness Microstructural Investigation of Temper Rolled Ferritic Steels for Thin Sheet Applications
Authors: Luis Caroline , Gaspérini Monique , Chauveau Thierry
Published: January 2010

This paper focuses on the analysis of the microstructure and of the texture through the sheet thickness after temper rolling of very thin ferritic steels. The study uses EBSD and X-Ray diffraction. Comparison is made between an interstitial-free (IF) steel and of some industrial low carbon ferritic steels used after ageing. The experimental results are discussed with respect to the anisotropy of the mechanical behaviour after temper rolling during simple shear tests.
Grain Boundary Modification by Si3N4 Additions and the Effect on Corrosion Behaviors in Two Sintered Nd-Fe-B Magnets
Authors: Liu Qiong Zhen , Zhang Lan Ting , Shan Ai Dang , Wu Jian Sheng , Komuro Matahiro
Published: January 2010

Two sintered magnets Nd15Dy1.2Fe77Al0.8B6 and Nd22Fe71B7 were modified by intergranular additions of Si3N4. The remanence as well as sintering density of the two magnets increased slightly with appropriate amount of Si3N4 additives. Meanwhile, there was an obvious increase in coercivity of the Nd-rich Nd22Fe71B7 magnet after 0.3 wt. % Si3N4 was added to magnets. Besides the effects on magnetic properties, an improved corrosion resistance was observed. Compared with the native magnets without any additions, corrosion potential of the magnets with Si3N4 additives is more positive and the current density in the anodic branch of the polarization curve is reduced. Microstructure observation reveals that Si3N4 additives have been incorporated into the intergranular phases in the magnets. Si is found to enrich in the Nd-rich intergranular phase with low oxygen content. With the introduction of Si3N4 additives, more intergranular phase with high oxygen content is formed, which may contribute to improved corrosion resistance. In addition, addition of Si3N4 refines the grain size of Nd22Fe71B7.
Microstructure and Thermal Diffusivity of Gd2Zr2O7 Powders
Authors: Moskal Grzegorz , Rozmysłowska Aleksandra
Published: January 2010

The selection of new TBC materials is restricted by few basic requirements such as: high melting point, no phase transformation between room and the operation temperatures, low thermal conductivity, chemical inertness to the combustion gases and environment, thermal expansion match with the metallic substrate, good adherence to the metallic substrate and low sintering rate of the porous microstructure. Among these properties, one of the most important is thermal diffusivity. The number of material that can be used as TBCs is limited and so far only a few materials have been found to basically satisfy these requirements. Recent research has shown that certain rare-earth zirconates, such as Gd2Zr2O7, have even lower thermal conductivities than 7YSZ, and this has spurred an intensive research in discovering alternative TBC materials. The results of microstructure tests performed on the powders intended for thermally sprayed TBCs with APS method were presented in this article. The tests of phase and chemical composition of the analysed powder were performed. The carbon, sulphur and gas nitrogen contents were, among other things, determined during those tests. The x-ray powder diffraction phase identification in as received material was determined. The tested material showed the presence of Gd2Zr2O7 compound as the predominant one and Gd2O3 and ZrO2 oxides. The surface morphology analysis of the powder was carried out and its internal structure was characterized. The tested material shows porous structure typical for agglomerated powders. The second testing area applied to analysis of the powder thermal properties. The thermal diffusivity of the compressed samples with density similar to the solid material was determined with the laser flash (LF) method. The measurement results show that requirements for the materials used for new generation TBCs are met.
Stress Relaxation in Sandwiched Si3N4/Al/Si3N4 Thin Films
Authors: Chang G.R. , Ma Fei , Ma B. , Xu Ke Wei
Published: January 2010

An in-situ investigation was performed on the stress relaxation of sandwiched Si3N4/Al/Si3N4 thin films by using multi-beam optical stress sensor (MOSS), a developed technique for substrate curvature measurement. Furthermore, the microstructures of the thin films were characterized by several analyzing techniques, such as X-ray Photoelectron Spectroscopy (XPS), Field Emission Scanning Electron Microscope (FE-SEM) and X-ray energy dispersive spectroscopy (EDS). The results indicated sharp rise and drop of the residual stress due to the cracks of Si3N4 surface layer or the separation of Al particles during annealing process. An appropriate model was suggested to interpret this phenomenon.
Mechanical Behaviors of Nanoimprinted Cu-Ni Alloys Using Molecular Dynamics Simulation
Authors: Fang Te Hua , Chang Win Jin , Lee Haw Long , Wu Sie Jhan
Published: January 2010

Molecular dynamics (MD) simulation with a tight-binding potential is used to studied the mechanical behaviors of nanoimprinted Cu-Ni alloys before and after annealing. The annealing process consists of three different stages. Initially, there is a gradual heating from the original temperature of 300 K to the specified annealing temperature of 823 K and then it is followed by a period of constant heating at that temperature, after which the specimen temperature is allowed to cool gradually to the original temperature. The results showed that when the punch is advancing, the punching force obtained from the simulation with a tight-binding potential is lower than with the Morse potential. The internal energy of Cu-Ni alloys decreased with increasing the temperature and the component of Cu during the annealing process. In addition, comparing the residual stress in the Cu-Ni alloys with and without annealing treatment, the stress is significantly released after annealing.
Floatation Separation Research on Siderite-Containing Iron Concentrate
Authors: Yin Wan Zhong , Han Yue Xin , Xie Feng
Published: January 2010

With the development of mining operation, the content of iron carbonate typically siderite increases evidently in the iron ore produced in Dong Anshan floatation plant, China. The presence of siderite significantly decreases the iron grade in the concentrate produced by the current reverse anionic flotation process. The study shows that the floatability of hematite, siderite and quartz differs with an increase of pH by using the combination of starch and CaCl2 as depressant. A two-step flotation process has been developed to treat Dong Anshan iron ore by which siderite was removed in the first step floatation and in the second step, reverse anionic flotation was used to produce high quality iron concentrate.
Fundamental Research in Comprehensive Utilization of Bayan Obo Ore by Direct Reduction
Authors: Gao Peng , Han Yue Xin , Li Yan Jun , Ma Wei Ye
Published: January 2010

With the problems of hard processing, low efficiency and heavy pollution in Bayan Obo ore, A new combination flowsheet of coal-based direct reduction - benificiation was proposed to deal with the ore. By adjusting the parameters of temperature, time and ratio of carbon, the procedure of direct reduction is optimized and the iron is enrichment effectively. Experimental results show that the with the conditions of reduction temperature is 1225°C, reduction time is 30 mins and ratio of carbon is 2, the grade, metallization rate and recovery of the iron powder are 93.33%, 94.18% and 88.93% respectively. The iron powder by this process can be used as the raw material of converter steel making.
Preparation and Particle Size Characterization of Cu Nanoparticles Prepared by Anodic Arc Plasma
Authors: Qiao Hong Xia , Wei Zhi Qiang , Zhou Ming Ru , He Zhong Mao
Published: January 2010

Copper nanoparticles were successfully prepared in large scales by means of anodic arc discharging plasma method in inert atmosphere. The particle size, specific surface area, crystal structure and morphology of the samples were characterized by X-ray diffraction (XRD), BET equation, transmission electron microscopy (TEM) and the corresponding selected area electron diffraction (SAED). The experiment results indicate that the crystal structure of the samples is fcc structure as same as that of the bulk materials. The specific surface area is is 11 m2/g, with the particle size distribution ranging from 30 to 90 nm, the average particle size about 67nm obtained from TEM and confirmed from XRD and BET results. The nanoparticles have uniform size, higher purity, narrow size distribution and spherical shape can be prepared by this convenient and effective method.
Preparation of Silica Abrasives from Water Glass and Application in Silicon Wafer Polishing
Authors: Hu X.K. , Song Zhi Tang , Wang H.B. , Liu W.L. , Qin F. , Zhang Z.F.
Published: January 2010

Chemical mechanical polishing technique is more frequently adopted for planarization in integrated circuit fabrication. The silica abrasives in colloidal state are fabricated with the sodium silicate solution as raw materials through the polymerization reaction among silicic acid molecules. By continuous injection of silicic acid into the preexisting silica solution, the diameter of silica nanoparticles increases. The different sized silica nanoparticles are imaged by scanning electron microscopy, and the dried silica are characterized by X-ray diffraction and thermal analysis. The polishing test on silicon wafer with as-fabricated silica abrasives shows that the surface flatness reaches 1.1 nm roughness, however, micro scratches are still present in the surface.
Preparation of Zinc-Flake by High Energy Milling
Authors: Cai Xiao Lan , Xiang Hong Yin , Pei Zhi Ming
Published: January 2010

A kind of new Production flowchart of zinc-flake had investigated by use of the high energy milling(HEM) under the protection of inert gas, researched the properties of effects of zinc-flake of the starting powder, surfactants ,milling Production flowchart by high energy milling .
Synthesis, Characterization and Growth Mechanism of Nano-Scale Hydroxyl Magnesium Silicate
Authors: Gao Fei , Xu Yi , Xu Bin Shi , Zhang Bao Sen
Published: January 2010

Nano-scale hydroxyl magnesium silicate was synthesized successfully by using hydrothermal method. The composition of as-prepared powder was proved chrysotile which adheres to monoclinic crystal system (a kind of hydroxyl magnesium silicate) by using X-ray Diffraction (XRD) technology. The morphology and microstructure of chrysotile powder were characterized by using scanning electron microscope (SEM) and transmission electron microscope (TEM). Nano-particles and nano-rods were observed in SEM micrograph. Moreover, smaller-size nano-particles and nano-fibres were observed by using TEM. Based on results of SEM and TEM, the growth mechanism of chrysotile powder under hydrothermal conditions was discussed.
Cubic-Shaped Nano-MgO Powder and its Infrared Absorption Properties
Authors: Zhu Yi Min , Han Yue Xin , Liu Guo Liang
Published: January 2010

A precipitation-pyrolysis process was used for the synthesis of cubic nano-MgO powder. The main effect factors on the size and shape of nano-MgO powder such as mechanical stirring rate, organic reagent, and calcinations of the process were investigated. XRD and TEM were used to study on composition, morphology and size of nano-MgO powder. The results indicate that at the condition of mechanical stirring rate 510 rmp, glycol as organic crystal controller, calcination time 3 h, cubic nano-MgO powder was prepared with average size of 35 nm. FTIR results show that cubic nano-MgO powder has abnormal infrared absorption behaviors compared with that of micron scale.
Combustion Synthesis of Si3N4/MoSi2 Composite
Authors: Xu Jian Guang , Guo Shi Bo , Yan Jian Hui , Zhang Da Gong
Published: January 2010

Si3N4 particle reinforced MoSi2 composite powder has been successfully synthesized combustion synthesis method. XRD and SEM results showed that the combustion product was mainly composed by MoSi2 and Si3N4. The as-prepared Si3N4/MoSi2 composite powder has been pressureless sintered at 1600°C for 1h. The microstructure and mechanical properties of the composite were investigated. Relative densities of the monolithic material and composite were 92.2% and 89.6%, respectively. The composite has higher Vicker’s hardness and flexural strength than monolithic MoSi2. Especially the room-temperature fracture toughness of the composite is from 4.21MPa•m1/2 for MoSi2 to 7.25MPa•m1/2 for composite, increased by 72.2%, respectively. The morphology of fractured surface of composite revealed the mechanism of improving mechanical properties of MoSi2 matrix. The results of this work showed that in situ Si3N4/MoSi2 composite powder prepared by combustion synthesis could be successfully pressureless sintered and significant improvement of mechanical properties could be achieved.
Co-Precipitation Synthesis and Optimization Process for LiCo1/3Ni1/3Mn1/3O2
Authors: Zhang Pei Xin , Lin Mu Chong , Yuan Qiu Hua , Fan Zhen Zhen , Ren Xiang Zhong , Zhang Dong Yun
Published: January 2010

With the acetates of nickel, manganese and cobalt as raw materials and lithium hydroxide as precipitation agent, the precursor Ni1 / 3 Co1 / 3 Mn1 / 3 (OH) 2 was first prepared by chemical coprecipitation method, which was then mixed and ballmilled with certain stoichiometric ratios of LiOH∙H2O, and ultimately obtained LiCo1/3Mn1/3Ni1/3O2 after calcination process. Single-factor experiment method, in conjunction with XRD, SEM, and charge-discharge test, was utilized to study the influence of various factors, including the dispersion way of precursor, pH value of reaction solution, and the content of ballmilling lithium on the electrochemical properties of LiCo1/3Mn1/3Ni1/3O2. The results indicated that: (1) the material dispersed by ultrasonic treatment revealed excellent cycling performance, its ratio of capacity fading decreased at least 34.1% compared to those without ultrasonic process; (2) the optimum conditions of fabricating LiCo1/3Mn1/3Ni1/3O2 may be summarized as the treatment of ultrasonic dispersion, suitable pH value (12~13) and stoichiometric ratio (1.0) of ballmilling lithium.
Experimental Study on Developing White Carbon Black by Using Wollastonite
Authors: Dai Shu Juan , Yang Shu Yong , Hu Zhi Gang , Bai Li Mei
Published: January 2010

Introduction of White carbon black’s property and the technological flow of developing. White carbon black by using Wollastonite and factors that influences it .The conditions of the experimental are that the ratio of hydrochloric acid’s volume(hydrochloric acid’s concentration is 36%) and the weight of Wollastonite is 1.50 L/kg ,reactive concentration is 20%,the temperature is 50 centigrade, and reaction time is 30 minutes. Then purify it in order to meet the requirement of rubber reinforcement and the content of SiO2 is over 90%.The White carbon black coproduct is CaCl2, the purity of which is 96.76%,and can be used in industry.
A Disposable Polydimethylsiloxane Microdevice for DNA Amplification
Authors: Lekwichai A. , Porntheeraphat S. , Bunjongpru Win , Sripumkhai W. , Supadech J. , Rahong S. , Hruanun C. , Poyai Amporn , Nukeaw J.
Published: January 2010

In this study, we demonstrate the disposable polydimethylsiloxane (PDMS) microchip provided for DNA amplification. The device consists of two main parts. The first part is PDMS/glass stationary chamber, the other part is a temperature-control microdevice on SiO2/Si substrate. This device consists of a thin film Pt-microheater and a Pt-temperature sensor, which were fabricated with CMOS compatible process. The performance of the device in the DNA amplification shows that, with 10 μl of PCR mixture volume, the approximately 700 bp DNA were successfully amplified within 50 minutes by 30 PCR cycles. The amplified products were comparable with those of a conventional method using electrophoresis. The PCR chip is also suitable for mass production.
Grafting of Phosphonate Monomer onto Natural Rubber Latexes via Emulsion Polymerization
Authors: Kokklin K. , Tangpasuthadol V. , Bhanthumnavin Worawan
Published: January 2010

The synthesis of phosphorus-containing monomer, methacryloyloxyethyl phenyl benzenephosphonate (MPBP), was carried out. The monomer was successfully prepared as evidenced by 1H NMR, 13C NMR, FT-IR and MS analyses. Subsequently, MPBP was grafted onto natural rubber particles via emulsion polymerization. It was found that as the reaction temperature increased from 40 to 70 oC, percent grafting efficiency increased from 72% to 85%. Transmission electron microscopy (TEM) of the grafted NR showed a semi core-shell morphology. Thermogravimetric analysis (TGA) of grafted NR indicated a two step degradation. Moreover, the grafted polyMPBP promoted the char residue of up to 3.5%. Flame tests revealed that the grafted NR exhibited an increased LOI value (20.5 %) over that of pure NR (17.0 %).
Study of PDMS Compounds Using the Adhesion Force Determined by AFM Force Distance Curve Measurements
Authors: Vanitparinyakul S. , Pattamang P. , Chanhom A. , Tunhoo B. , Thiwawong T. , Porntheeraphat S. , Nukeaw J.
Published: January 2010

The atomic force microscope(AFM) was used to perform surface force measurements in contact mode to investigate surface properties of model systems at the nanoscale. Three different Polydimethylsiloxane (PDMS) compounds were observed. The first consisted of pure PDMS, the second of PDMS blend with the nanoparticles Zinc Oxide(PDMS/ZnO) and the third of PDMS blend with the nanoparticles Zinc Oxide and toluene solvent(PDMS/ZnO/toluene), respectively. Surface morphology and the adhesion force were investigated by using atomic force microscopy. Force–distance curve measurement was performed in a contact mode, which used tip as silicon nitride. Moreover, we found a significantly different of the adhesion force when modified by nanoparticles ZnO and toluene solvent.
SnO2-Based Thin Film Gas Sensors with Functionalized Surface
Authors: Korotcenkov Ghenadii , Cho Beong Ki , Tolstoy Valery
Published: January 2010

New approach for the rational synthesis and surface functionalizing of SnO2 films aimed for gas sensors applications was discussed in this paper. It was shown that successive ionic layer deposition (SILD) technology due to its simplicity, low cost, and ability to control the deposition of nanolayers of various materials on rough surface can attract increased interest for those purposes.
Surface Morphology and Optical Property of Silver Nanoparticle Thin Film Prepared by Electrostatic Spray Deposition
Authors: Boonnuk Y. , Chanhom A. , Tunhoo B. , Thiwawong T. , Nukeaw J.
Published: January 2010

Silver nanoparticle thin films were deposited on glass substrates by electrostatics spray
deposition. Electrostatic spray condition was optimized by varying distance between nozzle and
substrate between 20 mm and 60 mm, deposition time was fixed at 5 minute. The surface
morphology and optical properties of films were carried out by using Atomic Force Microscope
(AFM), Field Emission Scanning Electron Microscopy (FE-SEM) and UV-Vis Spectrophotometer.
The results is indicate that the surface morphology of silver nanoparticle thin film show the grain
size of film near around 100 nm at distance between nozzle and substrate of 60 mm and the RMS
roughness decreases from 9.59 nm to 2.35 nm when distance between nozzle and substrate was
increased from 20 mm to 60 mm. The optical absorption spectra showed the main absorption peak
at 436 nm. When the distance between the nozzle and the substrate raise, decrease in absorption has
been observed.
Study of Carboxymethyl Cellulose from Papaya Peels as Binder in Ceramics
Authors: Rachtanapun Pornchai , Eitssayeam Sukum , Pengpat Kamonpan
Published: January 2010

Effects of carboxymethyl cellulose from papaya peel (CMCp) on the properties of ceramics were investigated. Cellulose was extracted from papaya peels by NaOH and then it was modified by chloro acetic acid to obtain carboxymethyl cellulose. The prepared CMCp was applied as a binder in ceramic slip in order to increase its viscosity. Sodium silicate was also added into the slip for providing a dispersion of slip and protecting the sedimentation of clay particles. Various concentrations of CMCp and commercial CMC (CMCc) (0.05, 0.1, 0.15, 0.2 and 0.25% w/w of dry weight of clays) were added into the slip. Effect of CMC on viscosity of the slip and the ceramic density were studied. The relationship between the ceramic properties such as, shrinkage, porosity, casting rate and bending strength (both green strength and fired strength), and CMC concentration was also observed. As increasing both CMCp and CMCc, viscosity increased while density decreased. The prepared ceramics (green ware and fired ware) added with CMCp were found to have higher strength and lower in %shrinkage than that of adding with CMCc. The thickness of the ceramic wall adding CMCc increased with increasing CMCc concentration, and time in contrast to that of CMCp as the thickness decreased with increasing CMCp concentration. However, the ceramics with addition of CMCp possessed higher strength than that of the commercial one.
Methylene Blue Degradation over Photocatalyst Bismuth Vanadate Powder Synthesized by the Hydrothermal Method
Authors: Pookmanee Pusit , Pingmuang Kanlaya , Kangwansupamonkon Wiyong , Phanichphant Sukon
Published: January 2010

Bismuth vanadate powder was synthesized by the hydrothermal method with bismuth nitrate and ammonium vanadate as the starting precursors with the mole ratio of bismuth and vanadium of 1:1. The mixed solution was adjusted with ammonium hydroxide until the pH of final solution was 7 and hydrothermally treated at 100 °C for 2-6h. The phase was studied by X-ray diffraction (XRD). Monoclinic structure was obtained after hydrothermal treated at 100 °C for 6h without calcination step. The morphology was investigated by scanning electron microscopy (SEM). The particle was needle-like in shape and highly agglomerate. The degradation of methylene blue over photocatalyst bismuth vanadate powder was examined by ultraviolet spectroscopy (UV). Bismuth vanadate powder synthesized by the hydrothermal method at 100 °C for 6h showed the highest photocatalytic activity.
Synthesis of Stainless Steel/CNTs Nanocomposite Powders
Authors: Kaewsai Duanghathai , Singjai Pisith , Niranatlumpong Pannada , Watcharapasorn Anucha , Jiansirisomboon Sukanda
Published: January 2010

Stainless steel/carbon nanotubes (CNTs) nanocomposite powders were synthesized by chemical vapor deposition (CVD) method with ethanol as a carbon source. The effects of synthesis temperature and time on microstructure and chemical composition of the powders were investigated. The as-received stainless steel powders were synthesized at temperature in between 550-800°C for 30-180 min at a pressure of 10 Torr. The optimum synthesis condition was found to be 800°C for 120 min. Average diameter of CNTs grown on stainless steel particles slightly increased with increasing growth temperature. The synthesis time, however, was found to have no effect on the size of CNTs.
Study on Chemical Vapour Sensing Property of Esterified Poly(vinyl Alcohol)
Authors: Sangngern S. , Sahasitthiwat Somboon , Koonsaeng N. , Laobuthee A.
Published: January 2010

Modification of poly(vinyl alcohol) (PVA) by esterification is one of alternative ways to prepare copolymers. The degree of esterification on PVA was determined by FTIR, 1H-NMR, and elemental analysis. Both polymers, i.e., PVA and esterified PVA were mixed with carbon black in DMSO and prepared as thin films onto the interdigited electrodes (IDE) by spin-coating technique to obtain chemical sensors. To investigate the chemical vapour sensing property, the chemical sensors were examined with various organic solvents such as hexane, toluene, alcohols, THF, ethyl acetate, etc.
Performance and Stability of Dye-Sensitized Solar Cells with Quasi-Solid State Electrolytes Base on N-Methyl-Quinoline Iodide
Authors: Wantawee S. , Saenthaweesuk S. , Pukird Supakorn , Saipin T. , Tipparach Udom
Published: January 2010

We have fabricated dye-sensitized solar cells (DSSCs) with quasi-solid state electrolytes base on N-methyl-quinoline iodide and studied the performance and stability of the cells at different temperatures. The quasi-solid state electrolytes were prepared from polymer gel electrolyte based on N-methyl-quinoline iodide and iodine. Pure-anatase nanocrystalline TiO2 films with absorption of standard N719 dye were employed as working electrodes. The maximum efficiency of the solar cells was 4.5 % under incident light of 100 mW/cm2. The cells also showed excellent stability for several months under irradiation of sunlight. The ionic conductivity of the electrolytes and the performance of the cells at different temperatures were presented.
Synthesis and Characterizations of PLLA/PEG Block Copolymers
Authors: Nguyen Thai Hien , Petchsuk Atitsa , Tangboriboonrat Pramuan , Opaprakasit Mantana , Sharp Alice , Opaprakasit Pakorn
Published: January 2010

Poly(lactic acid-co-ethylene glycol) (PLLA/PEG) copolymers were synthesized and their properties were characterized. The PLLA/PEG/PLLA triblock copolymers were synthesized by ring-opening polymerization from l-lactide (LLA) and PEG macroinitiator. Stannous octoate, Sn(Oct)2 was used as a catalyst. Effects of molecular weight of PEG (600, 2000 and 4000), LLA/OH molar ratios (95:5, 98:2) and a sequence of addition of the reactants on properties of the copolymers were investigated. The triblock copolymers were subsequently used in a production of multiblock copolymers by reacting with a chain-extending agent, hexamethylene diisocyanate (HMDI). Chemical structure and molecular weight of the copolymers were characterized by 1H-NMR, FTIR and GPC. The results showed that molecular weight of triblock copolymers varied from 4,500 to 10,200. After chain extension, multiblock copolymer with molecular weight of 16,490 was produced. Thermal properties of the copolymers were also examined by DSC.
Effect of Powder Surface Oxide on Compressive Properties of Aluminium Foams
Authors: Asavavisithchai Seksak
Published: January 2010

The compressive properties of aluminium foams have been shown to be affected by the oxide content in aluminium powders. An increase in the oxide content results in increasing compressive strength and energy absorption of the foams. Oxides were found to form a network of crumpled films which retards the drainage of aluminium melt during foaming. The presence of larger oxide network in foam structure due to higher oxide content in aluminium powders can effectively strengthen the Plateau borders and cell walls of the foams.
Adsorption Study of Soybean Oil on PEI-Modified Silica Particles
Authors: Janhom Sorapong
Published: January 2010

Adsorption of soybean oil Silica particles modified by cationic polymer (Polyethyleneimine, PEI) was studied. Zeta potential result shows an increase in positive charge on the surface of modified silica particles. The effects of various parameters on oil adsorption such as PEI concentration, pH, electrolyte concentration, and temperature were investigated. It was found that PEI enhances an adsorption of soybean oil on PEI-modified silica particles. The soybean oil adsorption on the modified silica increased with respect to PEI concentrations. It was revealed that the higher pH, the more soybean oil can be adsorbed on PEI-modified silica surfaces. The electrolyte and high temperature reduces the soybean oil adsorbed on the PEI-modified silica particles.
Characteristics of Microwave-Esterified Cellulose Film from Corn Husk and Cotton: Effects of Degree of Substitution
Authors: Saeng-On Jittiporn , Aht-Ong Duangdao
Published: January 2010

The modified cellulose film was synthesized from corn husk and waste cotton fabrics in LiCl/DMAc solvent system by esterification reaction under microwave energy using lauroyl chloride and DMAP as an esterifying agent and a catalyst, respectively. By varying microwave power and reaction time used in the esterification reaction, modified cellulose powder with various degree of substitution (DS) was obtained. The structure of modified cellulose was proved by FT-IR and 1H-NMR analysis. The DS value of modified cellulose was measured by 1H-NMR. The modified cellulose films with different DS values were prepared by casting method. The influences of DS values on the properties of the prepared modified cellulose films were tested for their wettability, water absorption, gloss, and tensile properties. The results showed significant effect of the cellulose source and the DS values on the properties of modified cellulose film. The modified cellulose from corn husk resulted in the film with greater tensile strength and elongation at break than the film from waste cotton fabrics. The esteried-cellulose from both sources with high DS values yielded the film with higher tensile properties and lower water absorption.
The Effect of Surface Modification of TiO2 on Mechanical Properties of Polyethylene Composite Film
Authors: Tangchantra N. , Kruenate Jittiporn , Aumnate Chuanchom , Sooksomsong Thammarak
Published: January 2010

To achieve a proper dispersion of nano-particles polymer matrix and to yield a better compatibility between the nano-particles and polymeric material, the use of different coupling agents for surface modification of nano-particle is recommended. In this research, surface of TiO2 was modified by hydrolytic condensation of titanium isopropoxide with three different silane coupling agents, hexadecyl trimethoxysilane (HTMS), triethoxyvinylsilane (TEVS) and aminopropyl trimethoxysilane (APS). The grafting of silane coupling agents on the TiO2 nano-particles surface was characterized using TGA and FTIR techniques. Mechanical properties of polyethylene composite films were evaluated via tensile strength measurement. Surface morphology of the particle was studied by SEM and TEM. The result showed that surface treatment TiO2 nano-particles with TEVS could improve dispersibility of TiO2 and showed the optimum mechanical properties.
Gas Sensing Properties of CuO Nanostructures Synthesized by Thermal Evaporation of Copper Metal Plate
Authors: Kasian Pristanuch , Pukird Supakorn
Published: January 2010

CuO nanostructures were synthesized by thermal evaporation method. Using Cu metal plate at temperature of 400oC for 24 hrs in one atmosphere of oxygen and studied structural and gas sensing properties. The CuO nanostructured were investigated by the stereo microscope (image analyzer), X-ray diffraction, scanning electron microscope. The diameter of CuO nanowires vary from 10 nm to 50 nm and length of several 10 micrometers. The sensitivity of CuO nanostructures and response were performed at room temperature for ethanol and CO2 sensor.
Photocatalytic Destruction of Methyl Orange by Titanium Dioxide Powder Synthesized by an Oxalate Co-Precipitation Method
Authors: Pookmanee Pusit , Angkana Sirion , Phanichphant Sukon
Published: January 2010

Titanium dioxide powder was synthesized by an oxalate co-precipitation method with titanium isopropoxide and oxalic acid as the starting precursors. White precipitate was obtained after adding ammonium hydroxide until the final pH of solution was 8 and then calcined at 400-800 °C for 2h. The phase was characterized by X-ray diffraction. Single phase anatase structure was obtained after calcination at 400 °C. Multi-phase of anatase and rutile structure was obtained after calcined at 600 and 800 °C. The morphology was investigated by scanning electron microscopy. The particle was irregular in shape and highly agglomerate with a range of particle size from 0.1-0.3 µm. The photocatalytic destruction of methyl orange by titanium dioxide was determined by Ultraviolet spectrophotometry. Titanium dioxide powder synthesized by an oxalate co-precipitation method after calcination at 800 °C showed the highest photocatalytic activity.
Study of the Relationships between the Chemical Structures of Azo Disperse Dyes and their Dyeing Properties on Polyester
Authors: Mungmeechai T. , Jantip Suesat , Suwanruji P.
Published: January 2010

A series of azo disperse dyes was synthesized using 4-nitro aniline and 2-chloro-4-nitro aniline as diazo components. The coupling components were N,N-diethyl aniline, N,N-bis-β-hydroxyethyl aniline, N,N-bis-β-acetoxyethyl aniline, N,N-diethyl-m-toluidine, N,N-bis-β-hydroxyethyl-m-toluidine and N,N-bis-β-acetoxyethyl-m-toluidine. The structures of the synthesized dyes were confirmed by TLC, 1H NMR and elemental analysis. The spectroscopic properties of the dyes when dissolved in the organic solvents viz. ethyl acetate and methyl benzoate, were investigated. The absorption spectra of the dyes showed a bathochromic shift when the polarity of the solvents increased. In addition, the substituent groups on the dye structures influenced the spectroscopic properties of the dyes. The dyeing properties of the dyes on poly(ethylene terephthalate) and poly(lactic acid) fabrics were also studied. The dyes exhibited a slight difference in shade on the two polyester fabrics. Heat and light fastness properties of the dyed fabrics were also examined.
Optical Investigation of Bi2O3-B2O3 Glass System
Authors: Boonin Kitipun , Kaewkhao Jakrapong , Limsuwan Pichet
Published: January 2010

Glasses with composition xBi2O3:(100-x)B2O3 with 30x70 (in mol%) have been prepared using the normal melt-quench technique and investigated their properties. The optical absorption spectra of the glasses have been measured in the wavelength range 400-700 nm. It has been found that, the fundamental absorption edge has been identified from the optical absorption spectra. The values of optical band gap were decreased and the molar volumes were increased, with the addition of Bi2O3, due to the formulation of non-bridging oxygen (NBOs).
Inhibition of Aluminum Alloy 2024 Corrosion by 4-Amino-5-Phenyl-4H-1, 2, 4-Trizole-3-Thiol in Highly Sulfuric Acid Solution
Authors: Musa Ahmed Y. , Mohamad Abu Bakar , Kadhum Abdul Amir H. , Takriff Mohd Sobri , Daud Abdul Razak , Kamarudin Siti Kartom
Published: January 2010

Electrochemical polarization and electrochemical impedance spectroscopy (EIS) were involved to study the corrosion inhibition of aluminum alloy 2024 in 2.5M H2SO4 solution by 4-amino-5-phenyl-4H-1, 2, 4-triazole-3-thiol (APTT) at 30 ○C. Potentiodynamic polarization results were comparable with those obtained by impedance measurements. Results showed that APTT performed as inhibitor for aluminum alloy 2024 corrosion in 2.5M H2SO4 solution and it attains an efficiency of more than 32% at 4×10- 4 M at 30 ○C . The inhibition efficiency increases with an increase in the concentration of APTT. Polarization curves show that APTT is a mix-type inhibitor. Changes in impedance parameters (charge transfer resistance, Rct, and double layer capacitance, Cdl) were indicative of adsorption of APTT on the aluminum alloy 2024 surface, leading to the formation of protective films
Evaluation of Yam (Dioscorea sp.) Starch and Arrowroot (Maranta arundinacea) Starch as Suspending Agent in Suspension
Authors: Piriyaprasarth Suchada , Patomchaiviwat Vipaluk , Sriamornsak Pornsak , Seangpongchawal Nate , Katewongsa Prachya , Akeuru Preeyanuch , Srijarreon Paranee , Suttiphratya Piyarat
Published: January 2010

The aim of our study was to evaluate the applicability of yam (Dioscorea sp.) starch and arrowroot (Maranta arundinacea) starch as suspending agents in suspension. Paracetamol was used as a model drug because of its low solubility. It was found that the optimal concentration as suspending agent in paracetamol suspension was in the range of 7-8% for yam starch and 5-6% for arrowroot starch. All formulations were stable within the period of study with pH of 5.4-6.9. These results were comparable to those obtained from the sodium carboxymethyl cellulose (sodium CMC) which is a common suspending agent. It could be concluded that yam starch and arrowroot starch showed suspending activity in paracetamol suspension and could be applied as commercial suspending agent.
Preparation and Characterizations of Electrospun Lactide-Based Polymeric Nanofibers
Authors: Thammawong C. , Petchsuk Atitsa , Opaprakasit Mantana , Chanunpanich N. , Tangboriboonrat Pramuan , Opaprakasit Pakorn
Published: January 2010

Poly(L)lactide (PLLA), aliphatic polyester, and poly(LLA-co-DLLA) copolymers consisting of 2.5, 7.5, 50% of DLLA content were also synthesized. PLLA was successfully electrospun by using 15wt% solution in (1DMF:3CHCl3) mixed solvent. 2.5, 7.5, 50% P(LLA-co-DLLA) copolymers were then spun at 8, 10, and 15wt% concentration in a single chloroform solvent, respective. The lactide-based polymeric nanofibers were characterized by Scanning Electron Microscope (SEM). Smooth surface morphology was observed in nanofibers produced from PLLA and 50% P(LLA-co-DLLA) copolymer. However, surface porosity was observed in the corresponding fibers from 2.5 and 7.5% P(LLA-co-DLLA) copolymers. These nanofibers have high potential for wide range of applications such as filter media, nano-sensor, drug delivery and tissue scaffold, especially, those derived from 2.5 and 7.5% P(LLA-co-DLLA) copolymers which contain high degree of porosity.
Development of Transdermal Patch Comprising Centella Asiatica Extract
Authors: Suwannachote Kongthong , Ritthidej Garnpimol C.
Published: January 2010

The purpose of this study was to develop matrix-type transdermal systems containing Centella asiatica extract for treatment of varicose veins by using various polymers such as ethylcellulose (EC), methylcellulose (MC), hydroxypropylmethylcellulose (HPMC), polyvinylpyrolidone (PVP) and hydroxyproply cellulose (HPC-H, HPC-M and HPC-L grades) at various concentrations (0.75%, 1.00%, 1.25%, 1.50%, 1.75% and 2.00%) and using 30% of propylene glycol (PG), diethyl phathalate (DEP), dibutyl phathalate (DBP), glycerine, polyethylene glycol (PEG) 400 as plasticizers. Centella asiatica extract at 7% of solid content of the formulation was added to the matrix formulation prior to pouring on backing layer which was prepared by using either EC as polymer and DBP as plasticizer or polyethylene wrap. It was found that the use of polyethylene wrap as backing layer, PG as plasticizer and HPC as matrix layer showed better appearance, flexibility and compatibility. It was also found that HPC-H and HPC-M showed high adhesion and stickiness. It was concluded that HPC at concentration of 1.75% and 2.00% could be formulated as satisfactory transdermal matrix-type patch for Centella asiatica extract.
Concentration Effect of Aqueous Synthesis on Biphasic Hydroxyapatite – β-Tricalcium Phosphate Composition
Authors: Alqap A.S.F. , Sopyan Iis , Zubir S.A.
Published: January 2010

Hydroxyapatite of calcium phosphate materials, one of the most frequently used ceramic material in biomedical application, has been produced via chemical reaction involves both calcium and phosphorus precursors. Effect of suspension concentration on available phases was investigated using a basis of 2 mole % excess of calcium oxide. The synthesis was performed at 90°C until paste was obtained. To improve crystallinity, hydroxyapatite was calcined at 900°C. However, β-TCP appeared as trace which varied in fraction with suspension concentration. Varying concentration is then one approaching method in designing phase composition through which a functional material could be attained.
Potention of Lignin, Lignin Sulfonate and Lignin Acetate from Palm Empty Bunch as an Additive Substance in Urea Fertilizer as an Effort to Reduce the Solubility of Urea Nitrogen
Authors: Arianie Lucy
Published: January 2010

Hydrophobic lignin’s character is used as the base of lignin usage as the binder in the urea fertilizer tablet. Lignin was isolated from black liquor of pulp and paper with palm empty bunch materials. Sulfonation of lignin isolate produced lignin sulfonate. Acetylation of lignin isolate produced lignin acetate. Lignin, lignin sulfonate and lignin acetate analyzed its solubility showed that lignin has no solubility in water. Therefore, urea fertilizer need to be modified by lignin. Nitrogen concentration of tablet lignin – urea with variation of lignin percentage 1,2,3,4 and 5 % examined with Kjehdahl method, produced nitrogen concentration in average 43%. Binding lignin isolate with percentage of 1 – 5 % to commercial urea fertilizer formed lignin – urea tablet. Its solubility test showed that lignin – urea formation will dissolve in 96 ; 137 ; 435 ; 759 ; 625 seconds, respectively. As control was commercial urea fertilizer with solubility’s time is 142 seconds.
Silver Thin Films Deposited by Compact Magnetron Sputtering System
Authors: Promros N. , Paosawatyanyong Boonchoat
Published: January 2010

A compact dc magnetron sputtering system capable of silver thin films depositions was designed and constructed. The novel small footprint sputtering head with target diameter of 52 mm was constructed utilizing powerful neodymium alloy magnet. Silver metal was sputter-deposited under various powers. Plasma parameters were analyzed by using the sweeping-bias single langmuir probe. The electron temperatures of the plasma glow were constant at approximately 2 eV even with the increasing of input power whereas plasma density increases with the increasing of the input power. The X-ray diffraction analysis (XRD) and scanning electron microscope (SEM) were used to study the crystalline structure and the surface morphology of the obtained silver thin films. Crystalline orientations of (111) and (200) in the silver films deposited on slide glass substrates were revealed from XRD pattern. The highest degrees of (111) and (200) orientations was obtained at the sputtering power between 0.228 and 0.265 Wcm-2. Sub-micron crystalline silver grain structure were observed using SEM micrographs. Facetted grain size and deposition rate of silver thin films increases as the sputtering power increases.
Synthesis and Characterization of SnO2 Nanowires Materials Prepared from Tin Powder
Authors: Inchidjuy P. , An Ki Seok , Pukird Supakorn
Published: January 2010

Tin dioxide (SnO2) materials are prepared by using vapor transport techniques through a vapor-liquid-solid (VLS) mechanism from Tin (Sn) powder. The SnO2 materials are synthesized onto the silicon substrate at temperatures 850 0C. Crystalline structure of SnO2 nanowires was investigated by X-ray diffraction (XRD) spectroscopy. XRD patterns of SnO2 exhibited tetragonal rutile structure with lattice parameters of a = 4.73 oA and c = 3.18 oA. Surface morphology of SnO2 films was characterized by scanning electron microscope (SEM), that SEM micrographs indicate nanowires-like structure. The Raman spectra of single-crystalline rutile SnO2 nanowires were studied, three vibration modes were observed at 475, 635 and 775 cm-1 corresponded to the typical feature of the SnO2 nanowires. A room temperature photoluminescence (PL) spectrum of SnO2 nanowires were in visible emission range.
Design Net-Grid Subwavelength Gratings for High Quantum Efficiency Photodetectors
Authors: Yang Yi Su , Huang Yong Qing , Ren Xiao Min , Ye Xian , Duan Xiao Feng , Huang Hui , Wang Qi
Published: January 2010

Subwavelength gratings (SWGs) that consist of net-grid structure are designed as infrared reflectors in this paper. By rigorous coupled wave approach (RCWA) and finite difference time domain (FDTD) method, we simulate its reflectivity which can reach 99.98% at 1.55μm while maintaining reflectivity higher than 99% across the 1.47-1.59μm wavelength range. We introduce SWG reflectors as the bottom mirrors in resonant cavity enhanced photodetectors (RCE PDs). RCE PD's quantum efficiency is increased to 95.7% at 1.55μm and the device has a significant size reduction compared with only using DBR bottom mirror.
Gallic Thermosensitive Gel
Authors: Yodkhum K. , Wannachaiyasit S. , Phaechamud Thawatchai
Published: January 2010

Gallic acid (G) is a natural phenolic compound that has potent antioxidant and antityrosinase activities. The solubility of gallic acid in aqueous system is rather poor. The purpose of this research is to develop the thermosensitive gel containing G based on Lutrol® F127 (L) and the antioxidant of prepared gels was determined using modified ABTS.+ method expressed as Vitamin C Equivalent Antioxidant Capacity (VCEAC) method. N-methyl pyrrolidone (N) could be used to effectively solubilize G into L aqueous systems. This developed thermosensitive system could convert from solution in the cool place to the firm gel under physiological condition on the skin to delivery an anti-aging agent such as gallic acid. Gallic acid gel prepared from hydroxypropyl methyl cellulose (HPMC, H) was employed to compare with the developed system. The developed gel containing 25% L, 25% N and 5% G (L25N25G5) showed the good physical appearances. In vitro release study was performed using the membrane-less method. The release of G from L25N25G5 into citrate-phosphate buffer pH 5.5 was faster than that of the gel containing 3% H, 25% N and 5% G (H3N25G5). From rheology study, L25N25G5 exhibited as a Newtonian flow at 4 °C and plastic flow at 28°C and 35 °C whereas H3N25G5 demonstrated as a pseudoplastic flow at all the three temperatures. Additionally, from VCEAC method, L25N25G5 exhibited a good antioxidant activity.
Chemical Characterization and Electrical Properties of Indium Oxynitride Grown by Reactive Gas-Timing RF Magnetron Sputtering
Authors: Sungthong A. , Khomdet P. , Porntheeraphat S. , Hruanun C. , Poyai Amporn , Nukeaw J.
Published: January 2010

This work investigates changes in the chemical composition of InON thin films, grown by reactive gas-timing rf magnetron sputtering with different O2:N2 timing ratio characterized by Auger Electron Microscope (AES), Raman Spectroscopy which are well correlated with the electrical properties of films. The existence of nitrogen and oxygen in the deposited InON thin films was revealed by AES. Two Raman active optical phonons have been clearly observed and assigned to InN E1(TO) at ~470 cm-1 and E1(LO) at ~570 cm-1 and also shifted with different O2:N2 timing ratio. The carrier mobility of InON thin films was decreased when the ratio of O2:N2 timing is increased.