bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiscale Bone Remodeling Prediction for Fully Porous-Coated (FPC) Dental Implant Supported Prosthesis
Authors: Rungsiyakull Chaiy , Li Qing , Li Wei , Swain Michael V.
Published: September 2009

This paper aims at providing a preliminary understanding in biomechanics with respect to the effect of FPC dental implants on bone remodelling. 2D multi-scale finite element models are created for a typical dental implantation setting. Under a certain mastication force (<200N), a global response from a macro-scale model (without considering coated surface morphology details) is first obtained and then it is transferred to the micro-scale models (with coated surface morphology details and various particle sizes) for micro-scale analysis. A strain energy density (SED) obtained from 2D micro-scale Finite Element Analysis (FEA) is used as a mechanical stimulus to determine the bone remodeling in term of the change in apparent bone densities for cancellous and cortical bones. The change in bone densities is examined as a result of bone remodelling activities over a period of 48 months.
The Effect of Excess Silane-69 Used for Surface Modification on Cure Characteristic and Mechanical Properties of Precipitated Silica Filled Natural Rubber (PSi/NR)
Authors: Thongpin Chanchai , Sangnil C. , Suerkong P. , Pongpilaiprertti A. , Sombatsompop Narongrit
Published: September 2009

This research is concentrated on the effect of concentration of silane-69 used for surface modification on precipitated silica (PSi), on cure characteristic and mechanical properties of PSi filled NR. The PSi content in this study was fixed at 20 phr in order to reveal the effect of silane used to modify PSi, on NR compound and vulcanizate. Moving Die Rheometer (MDR) was used to characterize cure characteristic of rubber compounds. Generally, scorch and cure time of NR would increase with the addition of PSi due to the absorption of accelerator on its surface whereas the addition of Si-69 modified PSi would reduce both scorch and cure time. It was found in this research that the excess amount of Si-69 used increased scorch and cure time of rubber compounds. This was thought to be that the excess of Si-69 led to the formation of polysiloxane clusters which could absorb accelerator in rubber compound and resulted in a prolonged scorch and cure time. In term of vulcanized rubber, it was found that maximum torque increased with the concentration of Si-69 up to 6 %. The polysiloxane formed during the cure characterization test was responsible for the slightly decreased torque after 6% of Si-69 treatment. Nonetheless, even with high concentration of Si-69 used, torque was still higher than that of untreated PSi filled NR. This is widely understood that sulfur atoms in Si-69 molecule are able to participate in the bonding between rubber and silane molecules resulted in the enhancement of crosslink density of the vulcanizate rubber. The increased of modulus at 200 % elongation, tensile strength under tension, with the silane concentration, was evidence of the crosslink enhancement. Tear strength and hardness of the vulcanizates exhibiting the increment, with the silane used, also clearly confirmed the bonding between Si-69 and rubber molecules. It was elucidated from the research that excess of Si-69 would lead to polysiloxane formation, cluster form of silane and crosslinking density. Scanning Electron Microscope (SEM) micrographs and swelling test are also presented to confirm the phenomena.
Research on the Antifouling Mechanisms of Copper and its Alloys
Authors: Ma Shi De , Zhao Xia , Wang Hong Ren , Duan Ji Zhou
Published: September 2009

In this paper, the in-situ exposure tests of 15 kinds of copper and its alloys were carried out in seawater at Zhanjiang Harbor for 12 months in order to study their anti-fouling abilities and anti-corrosion properties. In the same way, the in-situ anti-fouling tests of copper and bronze were performed in Qingdao for 8 years. Successively, the anti-fouling properties were analyzed combining with the electrochemical process of copper alloy corrosion and biology process of the adhesion. The chemical, physical and biological factors influencing the fouling properties of copper alloys were also investigated. The results showed that the coppers can equip themselves with antifouling performance by producing some toxic substances during the processes of chemical and electrochemical reaction. In addition, the antifouling ability was proved to relate to the exfoliation effect, which was the result of interaction between stain layer adhesion and spalling force of the attachments.
Study of AMP-Activated Protein Kinase Agonists by Structure-Based Drug Designing
Authors: Chang Yea Huey , Ho Tin Yun , Wu Chieh Hsi , Chen Chien Yu , Huang Hung Jin , Tsai Fuu Jen , Tsai Chang Hai , Chen Calvin Yu Chian
Published: September 2009

AMP-activated protein kinase (AMPK) is a metabolite- sensed protein kinase in various eukaryotes. The activated AMPK regulates important proteins which cause diabetes, obesity, metabolic aberrant, and also breast cancer. In this study, the yeast AMPK structure was used as a template to model the human AMPK structure. By homology modeling, the reliable AMPK structure was built, and the active binding site was defined corresponding to X-ray crystal structure of yeast AMPK By virtual screening the database., All the potent ligands had the H-bond interaction in the key residues, same as the control. Thus, we suggested the phenylamide derivates might be the potent AMPK agonists.
Behavior of Heavy Plastic Deformation of Cu-15Cr-0.1Zr In Situ Composite
Authors: Li Yan , Chen Xiao Hong , Liu Ping , Gao Lin Hua , Tian Bao Hong
Published: September 2009

The behavior of plastic deformation of Cu-15Cr-0.1Zr in-situ composite under different degree of cold drawing deformation was analyzed by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that both Cu and Cr phases are elongated along cold drawn direction and appear a fibrous morphology; However, Cu phase shows a thread-like fibrous morphology and Cr phase shows a band-like fibrous morphology. The two phases have a coherent relationship of (111)Cu //(011)Cr; When the degree of deformation(ε)is equal to 6.43, the relationship shows// [111]Cu // [110]Cr //cold drawn direction. Furthermore, forming two different morphologies of Cu and Cr phases during cold drawing is also analyzed.
A Structural Improvement of Breaker Plates and Analysis of their Dynamic Properties in Polymer Tube Extruders
Authors: Choi Jin Ho , Choi Seung Hyun , Song Kyung Seok , Kim Jae Yeol
Published: September 2009

For the analysis of various extruder models are used not only testing, but also diverse simulation techniques. Of them, the three-dimensional technique is widely used recently. In this study, the breaker plate in a polymer resin extruder was analyzed. The breaker plate changes the rotational motion of the polymer resin extruded from the screw barrel into a straight line motion before it passes through the die. Also, the size and number of circular holes in a breaker plate directly affect polymer resin extrusion molding. In this study, a 3-D modeling was used to conduct the structural improvement of breaker plates, and the thermal/flow analysis program CFdesign was used to conduct a dynamic property analysis in a bid to achieve the production stability of extruders.
Influence of Si Content on the Oxide Scale Formation of Ni-Based Alloy
Authors: Lei Chu , Chen Li Xiang , Zhang Ning , Yin Yan Sheng
Published: September 2009

Effects of silicon concentrations in Ni-Cr-based alloys on the formation of oxide scales were examined in reduced atmosphere. The morphology and oxide scale were compared based on the Si content. The formation and growth kinetics of the oxide scale are rather sensitive to the alloy microstructures and their corresponding Si contents. Oxide ridges formed on the eutectic structure preferentially, while a thinner and homogeneous oxide scale grew from the austenite matrix. The thicknesses of the oxide ridges and the oxide layer on the austenite matrix are dependent of their corresponding Si contents. The ridge-like feature indicates that the austenite/carbide phase boundaries offer fast diffusion paths for metal atom outward diffusion. The formation of SiO2 sub-layer at the oxide scale/metal interface can act as an effective diffusion barrier for atom outward diffusion.
3D Electromagnetic Simulation Study for the Distribution of Electromagnetic Field of Microwave Sintering Cavity
Authors: Chen Li Xiang , Lei Chu , Zhang Ning , Jin Chang Shun , Yin Yan Sheng
Published: September 2009

In this paper, we use electromagnetic simulation software HFSS to investigate the distribution of electromagnetic field of microwave sintering cavity, and establish a simulation model for the TE103 single mode cavity. We then obtain the optimal condition for the distribution of electromagnetic field by capturing the contour of distribution of electrical field of cavity through simulation. Our research shows that electromagnetic simulation software HFSS can use color to effectively demonstrate the intensity distribution of electromagnetic field of internal space and various cross-sections within the microwave sintering cavity, which provides a novel method for improving and applying new ways to compute and predict the key features of field distribution. The simulation results by HFSS can guide the practical microwave sintering techniques as well as the design and improvement of the sintering cavity.
Study on the Formation and Variation of Monodisperse Nano-Sized Polystyrene Beads by Suspension Polymerization with Hydrophilic Polymer as a Stabilizer
Authors: Moon Ji Yeon , Park Moon Soo
Published: September 2009

We found that monodisperse polymeric particles with diameters in the range of a few hundred nanometers can be prepared by suspension polymerization with water as its dispersing medium. The ratio between monomer and water was selected to be 10 and polymerization conducted at 70oC. Azobisisobutyronitrile was employed as an initiator and a polymer with strong hydrophilic end groups as a stabilizer. Particle diameter was found to vary between 100 and 200 nm depending on reaction conditions. An increase in monomer concentration contributes to an increase in particle diameter and deviation from monodispersity. The weight average molecular weight of polystyrene beads was found to be dependent on the reaction temperature and initiator concentration. Glass transition was determined to be between 100 and 105oC.
Electroresponsive Property of Novel Poly(acrylate- acryloyloxyethyl trimethyl ammonium chloride)/Clay Nanocomposite Hydrogels
Authors: Li Peng , Kim Nam Hoon , Bhadra Sambhu , Lee Joong Hee
Published: September 2009

The poly(acrylate-acryloyloxyethyl trimethyl ammonium chloride)/clay nanocomposite hydrogels (poly(AAc-DAc)/clay NC gels) with different clay contents were prepared by using clay as a cross-linker. The hydrogel exhibited good electroresponsive property and excellent mechanical property. The hydrogels initially bent toward the cathode side followed by anode side under an electric field. Concentrations of NaCl solution, voltage of electric field and clay content of the hydrogels have significant effects on the electroresponsive property of the hydrogels. Clay exhibited two opposite effects on the electroresponsive property of NC gels.
Positive Temperature Coefficient Behavior of HDPE/EVA Blends Filled with Carbon Black
Authors: Li Qi , Park Ok Kyung , Lee Joong Hee
Published: September 2009

The electrical resistivity and positive temperature coefficient (PTC) behavior of carbon black (CB)-filled high density polyethylene (HDPE) /ethylene-vinyl acetate copolymer (EVA) composites were investigated. At any particular CB content, the composite with the HDPE/EVA weight ratio 9/1 showed the lowest resistivity compared to other composites under investigation. The resistivity was decreased after the addition of small amount of EVA in HDPE with a particular CB loading. This is due to the improvement in dispersion of CB in HDPE in presence of small amount of EVA. However, the resistivity was again increased after the addition of higher amount of EVA due to the formation of an insulation polymer shield by EVA around CB particles. The nature and intensity of PTC was dependent on the HDPE/EVA ratio. With the increase in EVA content, PTC was shifted at a lower temperature. The highest PTC intensity was observed for the composite with HDPE/EVA ratio 8/2.
Partical Size and Morphology of Zeolite β Influenced by Various Conditions in the Hydrothermal Synthesis
Authors: Feng Xi Lan , Liu Yun Qi , Liu Chen Guang , Liu Chun Ying , Wang Huai Ping
Published: September 2009

Nanocrystalline zeolite β was synthesized by hydrothermal treatment, and the effect of aluminium source, SiO2/Al2O3 ratio, sodion, crystallization temperature etc. on particle size and morphology was studied. Under the optimum condition, zeolite β with the particle size about 100nm was successfully synthesized. The samples were characterized by XRD and TEM techniques, and the key factors influencing the particle size and morphology were revealed.
Evaluation of the Degree of Crystallization in Glass-Ceramics by Dielectric Constant Measurements
Authors: Han Ye , Yao Shu Yu , Sun Hai Qing , Zhang Wei Wei
Published: September 2009

A theoretical procedure was developed with the aim of obtaining a rapid and accurate estimation of the degree of crystallization in glasses obtained from fly ash by measuring the dielectric constants. Compositions were prepared by melting the mixture of fly ashes, nucleators, fusing agents and clearing agents at 1500°C. Dielectric constant measurements were carried out by means of universal bridge. The results were compared with the degree of crystallization as evaluated by the method of density and showed a good agreement.
Internal Friction of Ti-Rich Ti-Ni-Cu Melt-Spun Ribbon
Authors: He Wen Jun , Min Guang Hui , Yin Yan Sheng , Tolochko Oleg V.
Published: September 2009

Martensitic transformation (MT) and the internal friction (IF) behavior of the initially amorphous Ti-rich Ti-Ni-Cu melt-spun ribbon annealed at 400°C for 10 h were investigated by using DSC and dynamic mechanical analysis (DMA). The annealed ribbon shows B2 structure with strong preferential (110) orientation and exhibits B2↔B19 MT with the temperature hysteresis of 13°C. DMA tests show that the internal friction is frequencies dependence at 1-50 Hz. The tanδ values decrease with the increasing frequency, but it does not meet the 1/f dependence. Isothermal DMA tests show that the tanδ value at a temperature of 15°C in the MT zone increases quickly from 0.005 to 0.045 with the increasing isothermal intervals and keep stable subsequently. The isothermal time to complete the MT can be determined by the DMA tanδ curve directly.
Optochemical Film Sensor for the Determination of Free Chlorine in Water
Authors: Zhang Li , Dong Li Hua
Published: September 2009

An thin reagent containing optochemical film sensor for detecting and measuring free chlorine in water is described. The film sensor has been manufactured by immobilisation indicator of 3,5-dimethyl-4-hydroxybenzaldazine in a permeable transparent polymeric membrane. A linear calibration for free available chlorine can be obtained in the range between 0.05 and 3ppm. The limit of quantitation is 0.3 ppm, and the accuracy exceeds 7%. It takes about 150s to measure the relatively low occupational exposure concentration of 0.1ppm. The interference of combined chlorine has been studied. The sensor has no response to combined chlorine. And the stability of the sensors and the effect of external parameters like relative humidity (RH), temperature on the sensor response have been investigated. The sensor response is affected by varying the temperature; however, humidity in the range between 0 and 90% RH does not affect sensor response. The 3,5-dimethyl-4-hydroxybenzaldazine remained stable inside the polymeric film and no chemical reaction, crystallization or leaching occurred during 6 months of observation. Proper choice of indicator dye and polymeric material and successful application of kinetic evaluation method for the exposure experiments determine the desired features of the sensor.
Introduction
Development of Fiber-PZT Array Sensor System
Authors: Cheng Tai Hong , Lim Seong Hyun , Kee Chang Doo , Oh Il Kwon
Published: September 2009

In this study, array type fiber-PZT senor systems were newly developed with capabilities of detecting both damage location and monitoring of gas or liquid leakage by applying time-frequency analyses. The system consists of two piezoelectric transducers for the signal receiver and generator applications and three optical fibers for wave propagation. The results showed developed fiber-PZT array sensor can accurately measure the position of crack and its intensity. Also the fluid leakage of methyl alcohol as test specimen, on the plate structure has also been investigated employing the fiber-PZT sensors. The ultrasonic wave optical fiber sensor can be used effectively to monitor changes in structural and chemical properties.
Influence of the Axial Inserted Yarns on the Mechanical Properties of Multi-Angled Filament Wound Pipes
Authors: Xie Xia , Jiang Ya Ming , Xu Ai Fen , Huang Yong , Lu Xue Cheng , Shi Lei
Published: September 2009

The relationship between the axial inserted yarns and the mechanical properties of the multi-angled filament wound pipes was studied by experimental investigation in this paper. Firstly, the glassfiber/epoxy pipes with different process parameters were fabricated on the specially-designed filament winding equipment under varying conditions. Then the specimens were made in terms of standard sizes and tested under axial tensile load and axial compressive load, respectively. Furthermore, the axial tensile strength and the axial compressive strength were obtained from the test data, which showed that the above two values of the specimens with the axial yarns were larger than that without the axial yarns. That is to say, the incorporation of the axial reinforcement was found to result in increased strength.
The Micro Physical Mechanism Study of Metal Rubber Material on Compressive Performance
Authors: Wang You Yan , Bai Hong Bai , Tao Shu Ai
Published: September 2009

Metal rubber material is a new type of elastic and porous material which develops from metal materials. The macro-structure of metal rubber is reticular just as high polymer, made up of fine metal wires. In this paper, the testing equipment which can test micro-motion of metal rubber is designed and the compressive force-displacement curve along molding of metal rubber has gain. The cure along molding of metal rubber has three different characteristic stages. In different characteristic stages, the deformation of metal rubber material has different micro physical mechanism. The micro physical mechanism of different deformation periods is summarized by the micro analyses of three different characteristic curve stages and the study of metal rubber molding technology. Based on the manufacture technology and molding process, the spring wires in metal rubber material have contacted adequately after molding. The micro physical mechanism of metal rubber material in this stage is produced by blank tear combination deformation in linear elastic of spring wires. Because of the deformation stage is very little; the stiffness of metal rubber material is represented linear characteristic in this stage. The contacted points of spring wires are slide along with deformation increasing. The stiffness of metal rubber material is reduced after early linear deformation stage. The compressive force-displacement curve represents soft characteristic stage in macro- expression. When the most contacted points of spring wires are slide along with deformation increasing, the stiffness of metal rubber material is rapid rise. The exponential reinforcement stage is caused by the strongly constraints among spring wires. The micro physical mechanism can explain the different characteristic stages of metal rubber material on compressive performance.
High-Strength Porous Ceramics Produced by Recycling Glass Fibers in Waste GFRP
Authors: Kinoshita Hiroyuki , Kaizu Koichi , Miyagi Hiromori , Hitoo Tokunaga , Ikeda Kiyohiko
Published: September 2009

Ceramics, Composite Material, GFRP, Clay, Recycling, Bending strength
Abstract In this study, as the effective recycling technique for the waste GFRP, the process for the producing the porous glass fiber reinforced ceramics by firing the mixture of the clay and the crushed waste GFRP was proposed. The proposed recycling technique for the waste GFRP enables to produce various ceramics parts by effectively reusing the glass fibers included in the waste GFRP as well as to dispose injurious GFRP radically. By changing the mixing ratio of the waste GFRP and clay, and by firing the mixture at some temperatures, several kinds of ceramics specimens (tiles) were produced. The microstructure of each specimen was observed using the SEM and the microscope, and then water absorption and the bending strength of the specimens were examined in detail by comparison with those of specimens without the glass fiber. From those results, it was confirmed that the high-strength porous glass fiber reinforced ceramics could be produced by our proposed process.
Preparation of MgCl2-Coated Activated Carbon and its Adsorption Behavior of Azo Dye from Aqueous Solution
Authors: Sun Jin Xiang , Wang Hai Zeng , Sun Bao Wei
Published: September 2009

The preparation of MgCl2/AC composite and its adsorption behavior of azo dye from aqueous solution were investigated. The pore size of the new kinds of adsorbent increased with increasing the dosage of MgCl2 solution, while specific surface area decreased. The removal rate of Weak Acid Red 2R from aqueous solution on the MgCl2/AC composite was 93.4 % at the optimum conditions of the preparation: activated carbon with 2 M MgCl2 solution at 110°C for 2 h.
Extrusion and Evaluation of Saw Dust-Recovered HDPE Composite Bars
Authors: Lim Sean , Liu Jeremy , Jayaraman Krishnan
Published: September 2009

Wastes such as saw dust (Pinus Radiata) and milk bottles (High Density Polyethylene - HDPE) are available in abundance. HDPE bars and composite bars, consisting of different volume percentages (50%, 60% and 70%) of saw dust and recovered HDPE, were extruded using a co-rotating, conical, twin screw extruder with a slit-profile die and an innovative sizing-cooling box. The extruded bars were evaluated on their surface finish, shape conformance and materials distribution across the cross-section. Mechanical testing of the extruded bars was carried out using appropriate ASTM standards after they met the required quality ratings.
Degradation of MTBE by Using a Novel Magnetic Composite TiO2/Fe3O4 Photoreactor Design
Authors: Shen Chih Hsiu , Lo Shang Lien , Chang Chen Yu
Published: September 2009

Methyl tert-butyl ether (MTBE) is the most prevalent contaminant found in soil and groundwater and classified as a suspect carcinogen by Environmental Protection Agency (USEPA). Due to high water solubility, MTBE is not easy to be removed from contaminated groundwater. This study aimed to develop a novel and simple method to coat TiO2 photocatalyst on magnetic particles, evaluate its photocatalytic degradation effect on MTBE irradiated under visible (λ= 419 nm), and recollect easily from hydroponic systems with magnet. Iron nanoparticles are synthesized and added to TiO2 sol-gel followed by 500 oC calcinations. The results showed that the novel magnetic composite TiO2/Fe3O4 had significantly efficiency of photocatalytic degradation (91.6 %) for 10 ppm of MTBE under visible light irradiation and the recovery rate was relatively high as we recollected easily from recycled water using magnet.
Tribological and Thermal Properties of Hybrid Kevlar/PTFE Fabric Composite Filled with Nano-TiO2
Authors: Zu Da Lei , Yang Yu Lin , Zhang Rui Jun , Qi Xiao Wen
Published: September 2009

The hybrid Kevlar/PTFE(polytetrafluroethylene) fabric composites filled with different nano-Tio2 content of matrix resin were fabricated. To determine the tribological properties, the filled and unfilled composites sliding against 45 steel were performed on MM-200 friction and wear tester. Scanning electron microscopy(SEM) was utilized to examine the morphology of worn surface. Differential scanning calorimetry (DSC) analysis was also performed to study the thermal properties of the composites. The results show that the addition of nano-Tio2 improve the wear resistance and decrease the friction coefficient. The friction coefficient become unconstant during test with the increase of nano-Tio2 in the resin matrix, and the optimum fraction of nano-Tio2 in the resin is 1wt%. The SEM observations indicat that microcutting and plastic deformation are the main wear mechanisms. DSC analysis that there is no significant change in the melting points, and that there has been minimum chemical interaction between the resin matrix and nano-Tio2.
Self-Assembled Nano-Structures of Sandwich-Type Mixed (Phthalocyaninato)(porphyrinato) Rear Earth Complexes. Effect of Porphyrin-Phthalocyanine Ligands on Tuning the Inter-Molecular Interaction
Authors: Chen Li Na , Chen Yan Li , Zhu Pei Hua , Sun Guo Xin , Wang Hong Yan , Jiang Jian Zhuang
Published: September 2009

phthalocyanine, porphyrin, sandwich rare earth complex, nanostructure, self-assembly. Abstract. Three novel sandwich-type mixed (phthalocyaninato)(porphyrinato) rear earth complexes, namely Ce(DPP)(Pc)(1), Sm2(DPP)(Pc)2(2) and Sm2(DPP)2(Pc)(3) [Pc = dianion of phthalocyanine, DPP= dianion of 5,15-di(phenyl)porphyrin], have been fabricated into nano-assemblies onto the SiO2 surface by a surface assisted solvent-vapor annealing method. The effect of the number of porphyrin and phthalocyanine ligands on the morphology of self-assembled nanostructures of these double- and triple-decker complexes has been systematically studied. Competition and cooperation between the inter-molecular - interaction, van der Waals, and metal-ligand coordination for different compounds results in nanostructures with different morphology from approximately spherical shape with average size of ~300 nm and ~400 nm for 1 and 2, respectively, nano-rods with aspect ratio (length over width) around 5 for 3, which were characterized by electronic absorption, X-ray diffraction (XRD), and atomic force microscopy (AFM). Electronic absorption spectroscopic results reveal the formation of J-aggregates in the nano-structures and suggest the increasing - interaction in the order of 3, 1, to 2. Examination by XRD reveal that in the nanostructures of compounds 1-3, a dimeric supramolecular structure was formed through an intermolecular - interaction and/or van der Waals between two sandwich-type molecules, which as the building block self-assembles into the target nanostructures.
Properties of Carbon Nanofibers Prepared from Polyacrylonitrile/Poly(methyl Methacrylate) Blend
Authors: Pan Wei , Chen Yan , He Xiao Wei
Published: September 2009

The polyacrylonitrile(PAN)/poly (methyl methacrylate)(PMMA) blend fibers were prepared by wet-spinning technique and carbonized over the temperature range of 400-1000°C in nitrogen atmosphere. After carbonization of the blend fibers, the PMMA component removed and the PAN component left in the form of carbon nanofibers. Morphology of the carbon nanofibers were investigated via scanning electron microscopy (SEM), and the carbonization behavior of the fibers were examined via x-ray diffraction (XRD), Raman microspectrometry. The optimal condition made carbon fibers with great L/D ratio and diameter less than 200 nm. XRD and Raman spectra shows that the PAN/PMMA blend fibers treated at 600°C produced some graphite crystallite.
Factors Influencing Adsorption of PH3 on Modified Activated Carbon
Authors: Ren Bing Nan
Published: September 2009

Carbon materials have a very large surface area and various surface functional groups. They have been widely used as the adsorbent alone or the modified surface to adsorb pollutants. In the process of producing of yellow phosphorus by electric furnace, about 3000 m3 tail gas will be let out for one ton yellow phosphorus production. Tail gases consist of 90% of carbon monoxide (CO) and phosphine (PH3). The PH3 prevents the highly efficient utilization of CO and is an irritant and general systemic poison. Therefore, it is necessary to study how to effectively remove PH3 in tail gases. Due to the fact that selective adsorption of non-modified activated carbon (AC) is not enough to remove PH3 with a high efficiency, modification of AC might be an attractive route to improve the adsorption capacity. In this paper, experiments were carried out to study the factors influencing the adsorption of PH3 on the modified AC such as the concentration of impregnant, reaction temperature, oxygen content and space velocity. The results showed that the 5% HCl was the optimum concentration of impregnant. In the presence of oxygen, the adsorption capacity of modified AC was more than that in the absence of oxygen. In addition, with the improvement of the reaction temperature, the adsorption capacity of modified AC was increasing initially then decreasing, because of the transition from physical adsorption to chemical adsorption as priority. The adsorption capacity of the modified AC was enhanced initially with the increasing of oxygen content. Once the oxygen content was enhanced over 1%, there was no significant increase in the adsorption capacity of modified AC. The adsorption capacity of modified AC was decreased with the increasing of space velocity. The optimum parameters of reaction were 5% HCl of impregnant, 70°C of reaction temperature, 1% of oxygen content, and space velocity 10～20min-1.
Enhanced Bioactivity of Sandblasted and Acid-Etched Titanium Surfaces
Authors: Zhang En Wei , Wang Yan Bo , Gao Fei , Wei Shi Cheng , Zheng Yu Feng
Published: September 2009

Two new modified sandblasted and acid etched (SLA) surface methods had been used on commercially pure Ti (Cp-Ti) surface. Scanning electron microscopy investigation showed that modified SLA surfaces had micro- and nano-structure surface topography. Contact angle test showed that surface hydrophilicity was significantly increased after modified SLA surface modification. Human osteoblast-like MG63 cell attachment test showed that modified SLA surfaces would attach more cells than simple SLA surface. The alkaline phosphatase (ALP) activity assay indicated that ALP activity was enhanced on two modified SLA surfaces relative to SLA and mechanically polished Cp-Ti surface at early stage. Thus, subsequent chemical modification of SLA surface seems to be a promising method to generate better bioactive surface properties.
Investigation on Recycling Technology of Carbon Fiber Reinforced Epoxy Resin Cured with Amine
Authors: Ma Jin Huan , Wang Xin Bo , Li Bin , Huang Long Nan
Published: September 2009

An approach to chemical recycling of carbon fiber reinforced epoxy resin cured with amine has been investigated. Amine cured epoxy resin was decomposed totally when it was treated with nitric acid solution under certain conditions. The impacts of nitric acid concentration and decomposition temperature on recycling method were studied with decomposing time and the performance of carbon fiber as indexes. Epoxy resin matrix decomposed entirely after 23hrs at 95°C in the 8mol/L nitric acid solution. Scanning electron microscopy analysis (SEM) and monofilament strength were used to characterize the recycled carbon fibers.
Mechanical Properties of Carbon Nanotubes Reinforced Natural Rubber Composites
Authors: Jiang Hong Xia , Ni Qing Qing , Natsuki Toshiaki
Published: September 2009

Carbon nanotubes (CNTs) reinforced natural rubber (NR) composites with the CNT contents of 1, 3, 5, 10 and 20 wt% were synthesized using a solution casting method. The morphology of the composites was observed by scanning electron microscopy and Fourier transform infrared spectroscopy. It was found that CNTs were well distributed into NR and there was an excellent interface between CNTs and natural rubber. The mechanical properties of the composites were investigated by dynamic mechanical analysis (DMA) test and tensile test. It was found that the increment of storage modulus of NR/CNT composites was about 0.42 MPa/wt% in the rubbery state which agreed well with the results of tensile test. The large modulus increment confirmed the reinforcement effect of carbon nanotubes.
Wound Healing Based on PU/Hydrogel Nanocompounds Containing FGF-2 and Related Dressings by Radiation Method
Authors: Wu Te Hsing , Lin Hong Ru , Shen Lie Hang , Liu Jia Hau
Published: September 2009

PU/hydrogel compounds prepared byγ-ray radiation technique were investigated in
this study. We used nanosized clay solution or powder, Polyurethane (PU), thermosensitive N-isopropyl acrylamide (NIPAAm) and acrylic acid (AAc) as starting materials to prepare PU/hydrogel nanocomposite products. The dipping and weighing tests, Material Testing Machine (LLOYD) were utilized to analyze the physical and mechanical properties differentially. In
addition, the drug release and wound closure experiments were also finished by Enzyme-link immunosorbent assay (ELISA) reader and five groups of treatment dressings. From the final results, We obtained that the PU/hydrogel composite incorporating FGF-2 as a wound dressing
was able to effectively interact with the wound in a suitable moist healing environment. These composites make them more compatible with skin.
Nanostructured Ferrite Formation in Borosilicate Glass
Authors: Sandu Viorel , Popa Stelian , Pasuk Iuliana , Enculescu Ionut , Nicolescu Mirela Sidonia , Radicescu Simona
Published: September 2009

We present the preparation, structural, and magnetic properties of a series of Fe-containing borosilicate glasses as a function of the ratio SiO2/Fe2O3 which is ranging from 1.49 to 2.68. The role of nucleators (Cr2O3 and P2O5) was also investigated. X-Ray diffraction has revealed the formation of magnetite as the major or unique crystalline phase. As SEM micrographs have revealed, the addition of P2O5 give rise to a finer structure as compared with Cr2O3. In addition, the same oxide decreases the temperature of structural transition with almost 100 °C. The magnetization data reveal a two step transition at low temperatures: a high temperature transition at Tv = 128 K, which we attribute to the Verwey transition, and a low temperature transition at Ts = 48 K which, most likely, is the result of change in the dynamic of the domain motion.
Synthesis of Ag-Cu-Sn Nanocrystalline Alloys as Intermediate Temperature Solder by High Energy Ball Milling
Authors: Li Liang Feng , Qiu Tai , Yang Jian , Feng Yong Bao
Published: September 2009

To obtain intermediate temperature alloy solders with melting temperature of 400~600°C, (Ag-Cu28)-25Sn and (Ag-Cu28)-30Sn alloys were prepared by high energy ball milling. Ag-Cu-Sn nanocrystalline alloys have been obtained after milling for 40h. XRD results show that the (Ag-Cu28)-25Sn alloy consists of Ag4Sn and Cu3Sn, and the (Ag-Cu28)-30Sn alloy contains Ag4Sn, Cu3Sn and Cu6Sn5. The small polydispersed particles with size ranging from 1μm to about 25μm are observed from the (Ag-Cu28)-30Sn alloys milled for 40h by SEM. A large amount of small particles comprised of two or three grains are commonly observed by HRTEM, and average grain size is about 17.50nm. DSC results indicate that the melting points of the (Ag-Cu28)-25Sn and (Ag-Cu28)-30Sn alloys milled for 40h are 548.5°C and 539.3°C, respectively.
Fabrication and Optical Properties of Mn-Doped ZnO Nanowires
Authors: Wang Jian , Li Hui Feng , Huang Yun Hua , Zhang Yue
Published: September 2009

Mn-doped ZnO nanowires were successfully synthesized on silicon substrate by chemical vapor deposition method with Au catalyst. The X-ray diffraction (XRD) pattern indicates that the Mn-doped ZnO nanowires are hexagonal wurtzite structure and no second phase. The X-ray spectroscopy (EDX) and X-ray photoelectron spectrum (XPS) spectra exhibited the Mn ions were induced into the ZnO nanowires. Photoluminescence (PL) spectra were excited by 325 nm Xe lamp laser. Three peaks are observed in Mn-doped ZnO nanowires, two ultraviolet (UV) emissions at 370 nm and 386 nm, a visible emission at 405 nm. The emission at 405 nm is first found in Mn-doped ZnO nanowires that attributed to the electron transition from bottom of the conduction band to zinc vacancy defect energy level. The existence of Mn element changes the optical property of the ZnO nanowires.
Three-Dimensional Zinc Oxide Nanorod Networks
Authors: Li Hui Feng , Wang Jian , Huang Yun Hua , Zhang Yue
Published: September 2009

Three-dimensional (3D) ZnO nanorod networks were synthesized through the direct evaporation of metal zinc with high purity via a chymical evaporation deposition (CVD) method in Ar and O2 at 910 °C without any catalyst. The nanorod networks of as-synthesized ZnO were characterized using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD). The branches within one network show very regular orientation relationships: either perpendicular or parallel to each other. The nanorods follow a growth direction [0001]. Photoluminescence (PL) spectroscopy were measured at room temperature and showed the different PL features of other nanostructures. Two typical emission peaks at -401 nm and at 452-495 nm were observed. Specially, the emission peak at 452-495 nm includes four subordinate peaks.
A New Way to Manufacture a Carbon Nanotubes Supercapacitor
Authors: Hsieh Tung Feng , Chuang Chia Chih , Liu Ming Yang , Chou Yu Chuan , Shu Chi Min
Published: September 2009

A nanocomposite electrode of vertically aligned multi-walled carbon nanotubes (MWCNTs) on gold was fabricated to improve the specific capacitance and power density of the conventional supercapacitor. The novel supercapacitor built from MWCNTs and gold electrode showed a very high specific capacitance of 92.74 F/g using cyclic voltammetry (CV) at 10 mV/s, and 96.43 F/g was measured at 100 Hz. This nanocomposite electrode greatly enhanced the utilization efficiency of supercapacitor electrode material, low material cost and provided both high capacitance and power density. It was shown that the nanocomposite electrode based on vertically aligned carbon nanotube electrode had the characteristics of high specific capacitance.
Fabrication of TiAl/B4C Composites from an Al-Ti-B4C System Reinforced by TiC, TiB2 In Situ
Authors: Dong Li Hua , Zhang Wei Ke , Li Jian , Yin Yan Sheng
Published: September 2009

Near full dense B4C ceramic matrix composites were fabricated from Ti-Al-B4C system by combining high energy milling with hot pressing sintering. The effect of different content of Ti-Al on the mechanical properties and microstructure of the as-prepared composites was investigated. A TiAl/B4C composite, whose typical bending strength and fracture toughness are 437.3 MPa and 4.85 MPa•m1/2, respectively, was made. The sintering mechanism and reinforcement mechanism were discussed with the assistant of X-Ray diffraction and electron microscopy.
Fabrication and Photoelectric Properties of CdTe/TiO2 Nanocrystals Multilayer
Authors: Zhu Jian Chun , Gan Li Hua , Liu Ming Xian , Xu Zi Jie , Hao Zhi Xian , Zhu Da Zhang , Chen Long Wu
Published: September 2009

In this paper, we report the fabrication and photoelectric properties of CdTe/TiO2 nanocrystal multilayer. Negatively charged CdTe nanocrystal hydrosols were synthesized in the aqueous phase with 3-mercaptopropionic acid as a surface modifier. The characterization of transmission electron microscopy (TEM) and UV-visible absorption spectrum indicates the resultant CdTe nanocrystal hydrosols are monodisperse and have a very narrow size distribution with a mean diameter of about 5 nm. Clear TiO2 aqueous colloidal nanocrystals with positive surface charges were prepared by using tetrabutyl titanate as precursor. Through the electrostatic interaction between the positive surface charges on TiO2 nanocrystals and those on CdTe nanocrystal hydrosols, multilayer of CdTe/TiO2 nanocrystals were fabricated on the pretreated quartz substrate by layer-by-layer electrostatic self-assembly method. UV-Vis absorption spectrum and atomic force microscopy (AFM) were used to characterize the as-prepared CdTe/TiO2 multilayer. The results show that the surface of the CdTe/TiO2 multilayer are flat and the adsorption intensity in UV-Vis spectrum increases with the layer numbers of the CdTe/TiO2 complex, indicating that CdTe/TiO2 multilayer could be fabricated successfully on the surface of quartz glass and the resultant multilayer have good quality. In the same way, CdTe/TiO2 multilayer were fabricated on the surface of Indium Tin Oxides (ITO) substrate disposed by the poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS). The CdTe/TiO2 complex is measured under AM1.5G simulated solar illumination with 100mWcm-2 in air. The results show the maximum open circuit current density (Voc) and short circuit current density (Isc) of CdTe/TiO2 complex on ITO substrate is 0.45V and 0.050mA, which were better than TiO2 or CdTe nanocrystal hydrosols individual due to the interfacial hole-electron converter between the adjacent layers of CdTe and TiO2 nanocrystals.
Self-Assembly of PPV/CdTe Nanocrystal Complex for Photovoltaic Device
Authors: Tian Yu Chen , Gan Li Hua , Liu Ming Xian , Xu Zi Jie , Hao Zhi Xian , Zhu Da Zhang , Chen Long Wu
Published: September 2009

This work focuses on studying a novel polymer/nanocrystal multilayer for the fabrication of donor and accepter typed photovoltaic device. Highly luminescent anionic CdTe nanocrystals were prepared by aqueous synthesis method using 3-mercaptopropionic acid as stabilizer. The resultant CdTe served as electron acceptor and poly(p-phenylene vinylene) (PPV) was used as electron donor. Through the electrostatic interactions between cationic PPV precursor poly(p-xylene tetrahydrothiophenium chloride) and anionic poly(sodium4-styrenesulfonate) (PSS), PPV/PSS complex was fabricated on the surface of pretreated quartz substrate by layer-by-layer electrostatic self-assembly method. UV-Vis spectrum shows that PSS in the PPV/PSS complex make PPV precursors thermally convert into PPV at a lower temperature and less time. PPV/ PSS/PPV/CdTe multilayer were fabricated on the surface of quartz substrate by electrostatic self-assembly method. The surface of the polymer/CdTe complex is flat, which was characterized by atomic force microscopy (AFM). UV-Vis spectrum of the polymer/CdTe complex shows that the absorbance increases with the increase of the number of deposition cycles. In the same way, PPV/PSS/PPV/CdTe multilayer were fabricated on the surface of ITO substrate disposed by the poly(3,4- ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS). The resultant polymer/ CdTe complex is measured under AM1.5G simulated solar illumination with 100mW•cm-2 in air. The open circuit current density (VOC) and short circuit current density (JSC) of the polymer/CdTe complex are 0.60 V and 0.305 mA•cm-2 which are better than PPV or CdTe nanocrystal individual. This could be ascribed to interfacial hole-electron converter between the conjugated polymer layer and CdTe nanocrystal layer. Besides, the photovoltaic properties of PPV/CdTe complex can be improved by controlling the layers of PPV/ CdTe nanocrystals complex on the ITO substrate.
Microstructure, Mechanical Properties and Thermal Stability of TiAlN/Si3N4 Nano-Multilayer Films Deposited by Reactive Magnetron Sputtering
Authors: Yue Jiang Ling , Yin Yan Sheng , Li Ge Yang
Published: September 2009

A series of TiAlN/Si3N4 nano-multilayer films with various Si3N4 layer thicknesses were prepared by reactive magnetron sputtering. These multilayers were then annealed at temperatures ranging from 600 to 900°C in air for 1 hour. The composition, microstructure, and mechanical properties of the films were characterized by energy dispersive x-ray spectroscopy, x-ray diffraction, scanning electron microscopy, and nanoindentation. It reveals that under the template effect of TiAlN layers in multilayers, as-deposited amorphous Si3N4 is crystallized and grows coherently with TiAlN layers when Si3N4 layer thickness is below 0.6 nm. Correspondingly, the hardness and elastic modulus of the multilayers increase significantly. With further increase in the layer thickness, Si3N4 transforms into amorphous, resulting in a decrease of hardness and modulus. The TiAlN/Si3N4 nano-multilayers could retain their superlattice structure even up to 900°C. The small decrease in the hardness of multilayers annealed below 800°C was correlated to the release of compressive stress in multilayers. However, oxidation was found on the surface of multilayers when annealed at 800°C, which resulted in a marked decrease in the hardness of multilayers. The multilayers presented higher hardness as compared with the monolithic TiAlN film.
Surface and Composite Interface of Carbon Fiber Modified by Grafting of Diethanolamine
Authors: Chen Lei , Xu Zhi Wei , Li Jia Lu , Wu Xiao Qing , Chen Li
Published: September 2009

The γ-ray co-irradiation method was employed to study the effect of diethanolamine modification on the surface of carbon fiber (CF) and the interfacial properties of CF/epoxy composites. Compared with the original carbon fiber, the surface of modified fibers became rougher. The amount of oxygen-containing functional groups was increased and the nitrogen element was detected after irradiation grafting. The interlaminar shear strength (ILSS) of composites reinforced by carbon fibers irradiated in diethanolamine solution was increased and then decreased as the irradiation dose increased. The ILSS of CF/epoxy composites was enhanced by 16.1% at 200kGy dose, compared with that of untreated one. The γ-ray irradiation grafting is expected to be a promising method for the industrialized modification of carbon fibers.
Preparation and Properties of Fe3O4/PMMA Nanocomposite Films
Authors: Li Li , Zhao H. , Wang Wei , Nie F.F.
Published: September 2009

The magnetic Fe3O4 nanoparticles had been synthesized by co-precipitation process and surface treatment by silane coupling agent (KH570). The magnetic Fe3O4/PMMA nanocomposite films were prepared by blend method, and the chemical structure, mechanical properties, surface morphology and the biocompatibility of the nanocomposite films were studied in this work. The magnetic Fe3O4 nanoparticles were well dispersed in the Fe3O4/PMMA nanocomposite films. The strength of the nanocomposite films, as well as the strain, decreased first and then increased with the increasing of the nanoparticles. The hemolytic ratio indicated that the nanocomposite films had a better blood compatibility.
Preparation of Nanometer MgO by Ion Exchange Resin Method
Authors: Yang Min , Guo Hai Jun , Li Yan Sheng , Zhou Le
Published: September 2009

In this paper, nanometer MgO powder was prepared by using MgCl2•6H2O as the raw material, and environmental benign strong-base anion exchange resin as the induced-precipitation regent. The influence of the concentration of MgCl2 solution, drying method, calcination temperature and time on particle size and physico-chemical features of MgO was studied. The optimal technical conditions were obtained. The XRD and SEM results show that the nanometer MgO prepared under the optimal technical conditions has regular hexagonal lamellar structure, and is composed of nanocrystals with average size between 10 to 25 nm. The existence of dry N2 prevented the sintering of MgO during decomposition processing of Mg(OH)2. Compared with the other nanometer MgO preparation methods, ion exchange resin method has the advantages of low cost, low pollution, high yield and environmental benign; therefore, it appears to be a promising method for the industrial manufacturing of nanometer MgO.