bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Nano-SiO2 on the Rheology of Anionic Viscoelastic Solutions Formed by the Biodegradable Surfactant Fatty Acid Methyl Ester Sulfonate
Authors: Fan Hai Jun , Luo Ming Liang , Jia Zi Long , Sun Hou Tai
Published: August 2011

The effects of nano-SiO2 on the rheology of viscoelastic solutions formed by the bio- degradable surfactant fatty acid methyl ester sulfonate (MES) were studied. The process of MES micelles transforming from sphere or rod to wormlike was investigated with the increase in NaCl concentration by rheological measurements. The increase in η0 on the introduction of SiO2 was explained by considering the increasingly entangled wormlike micelles that were formed due to the screening of the electrostatic interactions. The results of rheological measurements show that the system of MES /NaCl can transform into wormlike micelles. MES micelle solutions without SiO2 are linear viscoelastic fluids in accord with a Maxwell model having a single relaxation time. But there is a process with some distributions of the relaxation time for MES micelle solution with SiO2.
Optimization of the Catalytic Wet Peroxide Oxidation of Phenol over the Fe/NH4Y Catalyst
Authors: Xu Jun Qiang , Guo Fang , Zou Shu Shu , Quan Xue Jun
Published: August 2011

The heterogeneous NH4Y zeolite-supported iron catalysts were prepared by incipient wetness impregnation. The catalysis oxidation degradation of phenol was carried over the heterogeneous catalyst in the peroxide catalytic oxidation process. Compared with the homogeneous Fenton process, the Fe/ NH4Y-acid catalyst can effectively degrade contaminants with high catalytic activity and easy catalyst separation from the solution. The phenol removal efficiency could reach 96% in the optimum experimental conditions. These process conditions were as follows: iron content is 5%, reaction time was 60 min, reaction temperature was 70 oC, the catalyst dosage was 1g/L, the H2O2 concentration was 1.65g/L.
The Analysis and Testing of the Natural Frequency of Air-Spring Precision Isolation Systems
Authors: Zhang Wen , Yin Jian Long , Jin Liang Bing , Li Dong Sheng
Published: August 2011

In order to solve the discordance between the engineering calculated natural frequency and the experimental natural frequency of the air-spring precision isolation system, the dynamic models of the air-spring isolation system were established and the engineering calculated natural frequency was 1.28Hz based on an isolation system. Then, impact experiments were carried out in lab and the experimental natural frequency was 1.22Hz using FFT method. The relative error between the two was less than 5%, which reached the expectations, and the error sources were briefly analyzed. The results of the research in this paper have reference value in designing and manufacturing of the air-spring precision isolation systems.
The Application of Nanotechnology in Acupoint Catgut Embedding Therapy
Authors: Xu Yun Xiang , Cai Jin Yuan , Liang Lin Qiu , Chen Gui Zhen , Xu Xiao Liang
Published: August 2011

The present paper aims to develop nano-thread materials for the settlement of the problem in acupoint catgut embedding therapy (ACET). On reviewing the current situation of ACET and pointing out the exiting problems and strategies, the authors explored the application of nano-technology in ACET, including developing nanometerized regular threads and nano material made threads. The nano-thread is supposed to better resolve the reverse reaction, improve the clinical therapeutic efficacy, and expand the clinical applications of ACET.
Isotherms for Aqueous Potassium Adsorption and Characterization of Natural Pyrophyllite
Authors: Chen Hai Feng , Tang Pei Song , Xu Min Hong , Cao Feng
Published: August 2011

The present investigatory founded an effectiveness of inexpensive and eco-friendly alumina silicate clay minerals, sericitic pyrophyllite (SP), as an adsorbent for the possible application in the absorption of K+. The crystal structure of pyrophyllite, size and morphology were characterized by XRD and SEM. In addition to pyrophyllite, quartz and were also contained in the minerals. The area of lamellar SP was about dozens um2. The results showed that potassium was absorbed on the SP under different pH and concentrations, and the best condition was pH=6, the time of equilibrium absorption = 30 min. It has been found that these natural minerals are effective in removing 55−75% of K+ from 5.0 to 20 mgL-1 KNO3 solutions. The applicability of the Langmuir, Freundlich and Dubinin-Radushkevich adsorption isotherms in each case of potassium was examined separately. We found that the adsorption process was endothermic in the case of SP and the Freundlich adsorption model was to more suitably represent the data. The work could provide the theoretical basis of the study of potassium ions adsorbed by pyrophyllite applying in fertilizer.
Fabrication of MWCNT-Reinforced Copper Composite and Thermal Expansion Behavor
Authors: Fan Z. F. , Chen X.H. , Xu L.S. , Liu Y. Q. , Zhong W. B. , She W. Y. , Zeng B.
Published: August 2011

A unique method for preparation of multi-walled carbon nanotube (MWCNT)- reinforced copper composite is reported. It involves solution phase systhesis MWCNT-implanted cuprous oxide composite spheres, formation of MWCNT/ copper composite spheres after reduction in H2 atmosphere and preparation of the MWCNT/copper bulk with vacuum hot pressing. Scanning Eelectron Microscope image (SEM) of the fracture surfaces indicate MWCNTs are homogeneously dispersed in the composite and bonded to the matrix. In addition, the thermal expansion of the composites at various MWCNTs (0wt%, 1wt%, 5wt%) were investigated. The coefficient of the thermal expansion (CTE) was decreased with increase of the MWCNT content, which are all much lower than that of pure copper.
Electrical Conductivity Research of Inhomogeneous Ceramic-Metal Composites
Authors: Feng Li Chao , Yu Xue Mei , Qiao Bin , He Yi Qiang
Published: August 2011

In this paper the electrical conductivity of Cu2O matrix inhomogeneous composites were tested. Cu2O matrix inhomogeneous composites, which were prepared by traditional powder metallurgy method, were with different Cu content and porosities. The results show that the electrical conductivity as a function of Cu content is consistent with percolation theory. The relationship between electrical conductivity and porosity can be calculated using the equation, . When the Cu content is below the percolation threshold, the temperature dependence of the electrical conductivity shows a hysteresis phenomenon.
Characterization and Properties of Organic Silicon Modified Vegetable Oil Fatliquor
Authors: Lü Bin , Ma Jian Zhong , Gao Dang Ge , Zhang Jing
Published: August 2011

The vegetable oil fatliquor (VF) was prepared by rapeseed oil, 1, 2-ethylenediamine and acrylic acid. The synthesis of a silicon modified vegetable oil fatliquor (SVF) was carried out using VF and polyether silicon by stirring and ultrasonic treatment. VF and SVF were measured by Fourier Transform Infrared Spectroscopy (FT-IR), thermogravimetry(TGA) and Transmission electron microscopy (TEM) respectively. SVF was applied in leather fatliquoring process, compared with product XQ-F3. The results indicated that polycondensation between hydroxy of polyether silicon and carboxylic hydroxy of VF occurred, the performance of VF could be improved by polyether silicon. The emulsifying surface tension of SVF decreased to 17.0 N/m, compared with 18.2 N/m of VF.The application results showed that the physical mechanical properties of leather fatliquored by SVF was equivalent to the leather fatliquored by industrial XQ-F3 fatliquor.
Silver-Supporting Diatomite Preparation and Antibacterial Performance Test
Authors: Hu Fen E , Wang Zhi Juan , Li Jun Li
Published: August 2011

The silver-supporting diatomite was prepared by the vacuum heating decomposition method with diatomite as the carrier and AgNO3 solution as the reaction solution. Its structure was characterized by X-ray diffraction (XRD). The factors influencing silver content of diatomite have been discussed in prepared silver-supporting diatomite. The results show that when the mass ratio of diatomite to AgNO3 is 10:1, the dipping time of 2 hours and the decomposing temperature of 350°C are suitable to preparing silver-supporting diatomite. XRD analyses show that the Ag loaded on the surface and micropore of the diatomite is nano-silver. The antimicrobial effect of silver-supporting diatomite was investigated against Escherichia coli (E. coli). The results show that the silver-supporting diatomite have obvious inhibiting effect on E. coli and its minimum inhibitory concentration decrease with increase of its silver content. The silver-supporting diatomite with the silver content of 1.46% is suitable to kill E. coli in water.
Rapid Degradation of Rhodamine B over Cyclodextrin Modified TiO2
Authors: Zhang Xu , Deng Nan Sheng
Published: August 2011

A novel β-cyclodextrin (β-CD) grafted titanium dioxide (TiO2/β-CD) was synthesized through photo-induced self assembly methods, and its structure was characterized. The TiO2/β-CD hybrid nanomaterial showed high photoactivity under visible light irradiation (λ  400 nm and/or λ  420 nm) and simulated solar irradiation (λ  365 nm). Photodegradation of rhodamine B followed the Langmuir–Hinshelwood kinetics model. The initial rate R0 of rhodamine B degradation increased by 4.6, 2.4 and 1.5 times in the irradiation conditions of λ  420 nm, λ  400 nm and λ  365 nm, respectively. β-CD increased the lifetimes of the excited states of the unreactive guests and facilitated the electron transfer from the excited dye to the TiO2 conduction band, which enhanced the dye pollutant degradation.
Perpendicular Magnetic Anisotropy in the CoFeB/Pt Multilayers by Extraordinary Hall Effect
Authors: Liu Na , Wang Hai , Zhu Tao
Published: August 2011

The perpendicular magnetic anisotropy (PMA) in as-deposited [CoFeB/Pt]n multilayers has been studied by using extraordinary Hall effect (EHE). A clear PMA has been observed in the ultrathin (~ 0.5 nm) amorphous CoFeB layer sandwiched by Pt. Moreover, PMA in as-deposited [CoFeB/Pt]n multilayers is strongly dependent on the thickness of CoFeB and Pt and the number of CoFeB/Pt bilayers. With the increasing thickness of CoFeB and the number of CoFeB/Pt bilayers, the hysteresis loops change from rectangle into bow-tie shaped.
Preparation and Evaluation of a W/O/W Double Emulsion Containing both Vitamin C and Vitamin E
Authors: Xia Qiang , Yao Yun Long
Published: August 2011

As the instability of vitamin C and vitamin E, double emulsion was chosen as a carrier system for dermal delivery of vitamins. The present work shows how to prepare and evaluate a double emulsion containing both vitamin C and vitamin E. The double emulsion was produced by two-step process. The concentration of vitamins were analyzed by UV, and the morphology of double emulsions were observed with optical microscopic. Vitamins could be protected well in one system, which was W/O/W double emulsion. The shape of double emulsion was also an evidence for the safety of vitamins. In the end, we obtained a stable double emulsion containing both vitamin C and vitamin E for cosmetics.
Cooling Water Screening Test of Corrosion and Scale Inhibitors
Authors: Sun Mo Jie , Lei Yu , Xi Li Juan , Liu Yong Hua , Wang Xu
Published: August 2011

Through to a certain power plant circulating cooling water do laboratory static scale and corrosion inhibition experiments, identified best dosage of three scale inhibitor A、B and C, which had improved the concentration rate of the circulating cooling water and had played an important role in preventing the circulation cooling water corrosion and scaling.
Oxidation Resistance of Ni-Co-ZrO2 Composite Coatings
Authors: Sun Wan Chang
Published: August 2011

Ni-Co alloy and ZrO2 particles were successfully codeposited on middle carbon steel substrate by electrodeposition. The oxidation resistance was evaluated by weight gains during high temperature oxidation test. The results indicate that, when the oxidation temperature is 573 K or 873 K, middle carbon steel, Ni-Co coating and Ni-Co-ZrO2 composite coating show lower weight gain. While the temperature is up to 1173 K, Ni-Co-ZrO2 composite coating possesses better oxidation resistance than Ni-Co coating and 45 steel. The reason may be that, the dispersive ZrO2 particles in the Ni-Co matrix reduce the effective area of Ni-Co alloy contacting with ambient oxygen, and new phases like NiO and CoO further prevent inward oxygen diffusion.
Preparation and Characterization of Spherical Mesoporous Material SBA-15 in the Presence of H3PO4
Authors: Li Wen Jiang , Yu Zhen Yun , Xie Fei , Qi Mei Zhou
Published: August 2011

The spherical mesoporous material SBA-15 was synthesized by amphiphilic triblock copolymer P123 as the template in the presence of phosphoric acid. The samples were characterized by polarizing microscope, N2 adsorption-desorption, XRD and SEM. The experimental conditions were studied in detail. We found that the perfect spherical SBA-15 with a good crystallinity and narrow pore size distribution could be obtained at 4 mol/L phosphoric acid, mild stirring rate, and 10 °C reacting temperature.
Efficient Photocatalytic Degradation of Bisphenol a over Urushiol Modified Titanium Dioxide under Visible Light Irradiation
Authors: Zhang Xu , Deng Nan Sheng
Published: August 2011

A novel urushiol grafted Degussa P25 (urushiol/P25) hybrid nano-material was synthesized, and its structure was characterized. The urushiol/P25 hybrid nanomaterial showed high photoactivity under visible light irradiation (λ  420 nm). Bisphenol A (BPA) can easily approach to P25 surface through the hydrophobic channel between alkyl groups in urushiol. The reaction rate constant of BPA degradation increased by 4.9 times by using 0.5% urushiol/P25 as catalyst than by using bare P25. Radical quenching experiments proved that the superoxide radical anion (O2•−) mediated oxidation pathways were dominant for BPA degradation.
Flow Characteristics of Microfilter in Slip/Transition Regime
Authors: Bao Fu Bing , Wang Jin Xing , Lin Jian Zhong
Published: August 2011

The Burnett equations with slip boundary conditions are used in present paper to investigate the flow characteristics of microfilter in slip/transition regime. Convergent results of the Burnett equations agree very well with the results of DSMC method. The difference between the results of the Burnett and the Navier-Stokes equations increases with the increase of Knudsen number. The variation of non-dimensional pressure drop with Reynolds number and the opening factor are presented. The non-dimensional pressure drop is independent of Knudsen number.
Microstructure Characterization of Rapid Solidification Al Alloy Foil
Authors: Li Yan , Zhai Chuan Xin , Xu Chun Hua
Published: August 2011

The AlMn and AlMnSi foils were fabricated by rapid solidification technology. The phase transformation temperatures, microstructures and distribution of elements were characterized by Differential Scanning Calorimetry (DSC), Transmission Electron Microscope (TEM), X-ray Diffraction (XRD) and Energy Disperse Spectroscopy (EDS) respectively. The result shows that the phases of AlMn7 nanofoil conclude Al, Al6Mn and quasicrystal phase, the crystal size is about 120nm; the phases of AlMn5Si5 nanofoil conclude Al, Al4.01MnSi0.74 and Al9Mn3Si, the crystal size is about 60nm. The phase transformation temperatures of AlMn7 and AlMn5Si5 nanofoils are 543K and over 873K, respectively. The microstructure morphology of AlMn7 nanofoil are rod, block and petal-like, but the microstructure morphology of AlMn5Si5 nanofoil is homogeneous globular.
Mechanical Characterization of Hepatoma Cells Using Atomic Force Microscope
Authors: Wang Jing He , Yu Miao , Liu Li , Zhao Jie , Wang Hong Xiang
Published: August 2011

In order to reveal variation of mechanical properties of hepatoma cells with nanometer resolution, atomic force microscopy (AFM)-based nanoindentation experiments are performed on hepatoma cell to derive Young’s modulus employing a corrected Hertz model. Under load conditions of nanoindentation force as 0.43809-0.73015nN and penetration rate as 0.4 Hz, the calculated value of Young’s modulus of hepatoma cells is 34.137±0.67kPa with a 95% confidence interval. The results demonstrate the Young’s modulus varies with the measurement position, and the center of cell possesses lower value than peripheral region. Variation of Young’s modulus is resulted from external reaction, which supports well the theory of cytoskeleton structure. Furthermore, the difference of Young’s modulus between normal cells and cancerous ones are also discussed, and it will provide possibility of a new route for early diagnosis of hepatoma.
Application of CdTe Quantum Dots to Development Fingerprints on Adhesive Surfaces
Authors: Yang Rui Qin , Wang Yong Gang , Xia Bin Bin , Wang Yan Ji , Liu Jian Jun
Published: August 2011

Water-soluble fluorescent CdTe quantum dots were synthesized using TGA (Thiolglycolic acid) as the stabilizer and characterized by fluorescence spectroscopy. This fluorescent material was applied to development fingerprints deposited on the sticky side of adhesives. The development conditions such as development time, temperature and pH value of QDs solution were investigated. The comparison experimental with traditional methods and development rate were also studied. The results show that this material exhibited strong visible fluorescence under excitation at 365 nm. CdTe QDs can detect fingerprints on different adhesive surfaces. In addition, the development rate of fingerprints on the adhesive side of cellulose tape was discussed and the effective development rate for 30-days-aged fingerprints can reach to 72%. Furthermore, the developed fingerprints have higher and stable fluorescence intensity, weaker background interference and better contrast between fingerprints and the substrate. CdTe QDs is a promising reagent for fingerprints development on adhesive surfaces.
Study on Tribological Properties of n-SiO2/FeS Solid Lubrication Composite Coating
Authors: Zhao Yu Qiang , Zang Yan , Qiao Yu Lin , Yang Shan Lin
Published: August 2011

The n-SiO2/FeS solid lubrication composite coating is prepared by means of the comprehensive treatment process of gridded laser quenching, low temperature ion sulfuration and vacuum impregnation technology. The tribological properties of n-SiO2/FeS solid lubrication composite coating are investigated under the condition of dry sliding, and the lubrication mechanisms are also preliminary discussed. The experiment results reveal that the friction coefficient of the coating is in the range of 0.065~0.10 when tested in 4067 minutes. Furthermore, its wear rate is only 6% of FeS solid lubrication duplex coating. This is testified that the n-SiO2/FeS solid lubrication composite coating is durable with low friction coefficient and wear resistance.
Environmentally Benign Microwave-Assisted Sonogashira Preparation of Aromatic Compounds
Authors: Puechmongkol Suttikiat , Paosawatyanyong Boonchoat , Bhanthumnavin Worawan
Published: August 2011

An efficient Sonogashira-type coupling reaction of terminal alkynes and aryl bromides by microwave activation with short reaction time under mild conditions are presented. It is illustrated herein that the traditional Sonogashira coupling reaction can be achieved with a much more efficient yet environmentally friendly condition. In contrary to the usually required 10 mol% Pd loading and the use of conventional heating at 60 °C for 24 h in order for a reaction to proceed satisfactorily, with a 100 W microwave activation, the reaction of terminal alkynes with substituted aryl bromides can be achieved with only a 2.5 mol% Pd in 10 min. The yield was improved with microwave irradiation.
Immobilization of Iron Tetrasulfophthalocyanine on MCF-NH2 and MCM-41 Mesoporous Silicas
Authors: Choi June Seok , Lee Sang Ho , Kwon Hyeok Hoi
Published: August 2011

Trace organic micropollutants have adverse effects on human health and ecosystem at low concentrations. In this study, feasibility of new catalysts for oxidation of organic micropollutants was investigated. Iron tetrasulfophthalocyanine (FeTsPc) has been immobilized on the surface of functionalized MCF (mesocellular silica form)-NH2 and MCM-41 mesoporous silicas by means of chemical bonding to ammosilane groups. MCF, prepared by precipitation from a micellar solution, consisted of unit cells which had internal void (~20 nm) and pores (~11 nm). NH2-functional groups were added to the surface of MCF and MCM-41 using (3-aminopropyl)triethoxysilane (APTES). 1-ethyl-3-(3’dimethylaminopropyl)carbodiimide (WSC) was used as a coupling agent. N-hydroxysuccinimide (NHS) was added during the reaction to improve the efficiency of amination. The prepared materials, FeTsPc/NH2-MCF and FeTsPc/NH2-MCM-41, were characterized by UV-DRS (diffuse reflectance UV-vis spectroscopy) and FT-IR. Bisphenol-A (BPA) was chosen as a model micropollutant. The catalytic activities of the supported Fe-TsPc were examined by the oxidation of BPA in the presence of hydroperoxide. The amount of immobilized FeTsPc and the specific reactivity were also analyzed to provide quantitative evaluation of the catalysts. The results indicated that the FeTsPc/NH2-MCM-41 showed higher activity and durability in the liquid-phase oxidation of BPA under mild condition compared with the FeTsPc/NH2-MCF and unsupported catalyst.
Reaction Synthesis of TiAl/Ti2AlC In Situ Composites
Authors: Zhu Jian Feng , Yang Wen Wen , Gong Yi Ping
Published: August 2011

Full dense and highly pure TiAl/Ti2AlC in situ composites were successfully synthesized by reactive synthesis from the powder mixtures of Ti, Al and carbon black by hot-press-assisted reaction process. The reaction process, microstructure and bending strength of the TiAl/Ti2AlC in situ composites were investigated in detail. The results show that the as fabricated composites posses three phases, namely, TiAl, Ti3Al and Ti2AlC. The matrix phases are mainly equiaxed TiAl with a minor lamellar Ti3Al phase. Ti2AlC particles with size less than 1 μm are distributed uniformly in matrix grains as a reinforcing phase. When C content is 0.44 wt %, the flexural strength reaches 426.21 MPa, which is increased by 35 %.
Study on the Roller-Bending Simulation to Promote Productivity in the HINGE STRAP Forming System
Authors: Chang Sung Ho , Heo Young Moo
Published: August 2011

The purpose of present study was to increase productivity and to promote the quality of the part in the forming system for hinge strap in automobile. So the roller-bending simulation was carried out to develop the forming system for the hinge strap. A square tube used in the roller-bending for the hinge strap was fabricated using process of the sheet forming and the welding. So study on the mechanical properties of the original metal sheet (SPCC 1.6t) and weld-line (including a HAZ) were performed before the roller-bending simulation. And the body forces of the roller (rigid body) in the roller-bending process simulation were calculated to make an accurate estimate the capacity of the oil pressure cylinder for a pressure device. Then the roller-bending process was divided into 5 steps for the simulation for validating the effect of the bending velocity on the springback. At the end, the shape after springback was estimated. The result was adopted in the design for the bending die.
Structure and Mechanical Properties of AlCrN Thin Films Deposited by Magnetron Sputtering
Authors: Pham T.T.H. , Le Bourhis Eric , Goudeau P. , Guérin P.
Published: August 2011

A magnetron sputtering system was used to deposit AlCrN thin films. Chemical compositions of the films were determined by both EDXS and RBS, while structures analyses were conducted by XRD in a Seifert XRD3000 diffractometer. Macroscopic residual stresses of films were determined by curvature measurements using DEKTAK IIA profilometer, while in-grain stresses were extracted by the “sin²Y method” from XRD measurements. A nanoindenter from CSM (Switzerland) was used to determine the hardness of the films. A CrN type FCC structure was obtained with a strong (200) fiber texture for the range of compositions Al1-xCrxNy(0.56 < x< 0.89) of interest here. The global stresses were compressive for all FCC films resulting from the high energetic deposition conditions used. In-grain compressive stresses were determined for the films with thickness < 500nm, while thicker films (> 500nm) showed tensile in-grain stresses. Stress-free lattice parameter a0strongly decreased from 4.13 to 3.97 A°. Hardness values were obtained in a range extending from 17 to 27 GPa with an increase obtained as Cr content increases and correlated to the residual-stress level.
Processing and Properties of Amorphous Magnesium-Based Eco-Materials
Authors: Fu X. L. , Tan Ming Jen , Jarfors Anders W.E. , Gupta Manoj
Published: August 2011

Magnesium alloys are the lightest known structural material and have been very attractive for usage in marine and transportation industry (for its weight savings and payload increase), and also for its portability in hand-held devices. It is recyclable and one of the most abundant metal. Lately, it has gained attention for its biocompatibility, and also its biodegradable properties depending on the alloying elements. They can be used as a biomaterial in various applications from heart stents to implant screws and fixtures. In this work, amorphous magnesium alloys have been processed, based on its glass forming ability, by various techniques in order to obtain its amorphous state, and the microstructure are characterized by thermal analysis, X-ray diffraction and electron microscopy. Their mechanical properties are also presented. High temperature tensile tests show similar strength to room temperature strength, while the total failure strain is significantly increased from around 0.5% to 10%.
A Study of Photo and Photocatalytic Degradation of Arylamine with Respect to Design of Organic Light-Emitting Diode
Authors: Han Chul Hee
Published: August 2011

In our study of organic molecules for OLED, we have paid attention to 4,4'-bis(N-carbazolyl)biphenyl (CBP), an arylamine commonly used as phosphorescent host or hole transport material in OLED, and performed photochemical and photocatalytic experiments. For the photocatalytic experiment, heterogeneous mixture of CBP and TiO2powder (Degussa P25) in tetrahydrofuran solution has been placed under UV radiation. Both photochemical and photocatalytic experiments have resulted in degradation of CBP, however, with widely different rates and degradation products. With ever increasing demand for high performance OLEDs, higher stability and longer lifetime of their organic components are essential. In this respect, current informations are sure to be valuable in the design and operation of OLEDs as well as arylamine-based OLED.
Analysis of Laser and Resistance Spot Weldments on Press-Hardened Steel
Authors: Kang Min Jung , Kim Cheol Hee
Published: August 2011

For the manufacture of safe, lightweight vehicles, the demand for ultra-high-strength steel in the automotive industry is increasing. Although transformation-induced plasticity (TRIP) and dual-phase (DP) steels have a strength of under 1 GPa, boron-alloyed steel produced using the hot press forming process has a strength of more than 1500 MPa. Laser and resistance spot welding processes are used to join press-hardened steel, but the characteristics of the resulting weldments are not yet fully understood. In this study, the thermal cycles for both welding processes were investigated using finite element (FE) analysis. Resistance spot welding was analyzed using a combination of thermal, electric, and mechanical models, whereas the thermal behavior of laser welding was predicted using only a thermal model. The calculated bead shapes were compared with experimentally measured ones to validate the simulation models. The mechanical and metallurgical characteristics of the weldments were explained using the thermal history of each welding process.
Cu (II)-Containing Micro-Arc Oxidation Ceramic Layers on Aluminum: Formation, Composition, and Catalytic Properties
Authors: Liu Dong Jie , Jiang Bai Ling , Zhai Min , Li Qiong
Published: August 2011

The ceramic layers containing Cu(II) were prepared by Micro-arc Oxidation on aluminum under alkaline electrolyte (NaSiO3; Cu(Ac)2; Na2WO4; Na3PO4; Na2B4O7). Using x ray photoelectron spectroscopy, scanning electron microscopy, ultraviolet spectrophotometry and chemical oxygen demand analyzer on the film composition, structure and catalytic properties were characterized. The results showed that when the Cu2p peaks emerged in XPS pattern, the corresponding substances were CuO and Al2CuO4, it told us that there had the catalyst in the ceramic coating composition containing CuO. As can be seen from the SEM image analysis, with the pulse width increased, the ceramic layer surface volcanic hole size also increased and the area density trended to loose. Meanwhile, phenol oxidation test results demonstrated that with the pulse width parameter increasing, the catalytic effect of the micro-arc oxidation ceramic layers trended to increasing. However, at higher pulse width such as 750 microseconds, the conversion rate of phenol was weakened strongly.
Effects of Physical Melt Treatments on Microstructural Evolution and Anodizing Characteristics of Al-Si Casting Alloys
Authors: Shin Je Sik , Kim Bong Hwan , Lee Sang Mok
Published: August 2011

In order to investigate the effects of physical melt treatment on microstructural feature and anodizing characteristics of Al-Si system casting alloys, A380 and A356 aluminum alloys were chosen and a twin-screw melt-shearing process was utilized before high pressure die casting. In order to refine and homogenize the microstructure of the diecast Al-Si alloys, the melt-shearing process parameters were controlled and T6 heat treatment was carried out.
Evaluation of Crack Sensitivity and Gap Bridging Ability during Laser Butt Welding of Aluminum 5J32 and 6K21 Alloys
Authors: Ahn Young Nam , Kim Cheol Hee
Published: August 2011

Growing demand to reduce fuel consumption has accelerated the application of Al sheets to the body structure of automobiles. While recent studies on laser welding of Al 5xxx series and Al 6xxx series alloys have examined weldability, the laser autogenous welding usually results in low gap bridging capability and weld defects such as porosity, underfill, cracking, and so on. In this study, we evaluated the gap bridging capability and the crack sensitivity during laser autogenous welding, laser welding with filler wire, and laser-arc hybrid welding, respectively. Al 5J32 and 6K21 sheets were used as the base metal and Al 4xxx series and Al 5xxx series wires were used as the filler metal. Employing adequate welding conditions, the gap bridging capability during butt welding was investigated for each welding process. To clarify the solidification crack sensitivity, bead-on-plate welding was implemented for a tapered specimen as a self-restraint crack test. Compared with the laser autogenous welding, laser welding with filler wire and the laser-arc hybrid welding showed improved gap bridging capability and reduced crack sensitivity.
Effects of Annealing Conditions on Morphology and Permeability of Palladium Membrane
Authors: Hemra Khanthima , Kitiwan Mettaya , Atong Duangduen
Published: August 2011

The palladium membranes were fabricated by mean of electroless plating method which provided thin and uniform film on a tubular alumina porous support. Subsequently, the annealing process which is one of the effective ways to enhance the permeability of membrane was performed in the temperature range of 600-800°C. The annealing temperature and time were found to have influence on membrane microstructure and its performance. Palladium annealed at 700°C for 8 hrs in nitrogen atmosphere had the highest hydrogen permeability and separation factor when operated at 600°C. The membrane morphologies observed by SEM showed that the sample treated at higher temperature had lower surface roughness. The annealed palladium composite membrane at 800°C revealed that some voids which occurred during electroless plating process were enlarged and caused the lower separation factor.
Preparation and Hydrogen Permeation on Al2O3-CuO-ZnO (ACZ)/Co Membrane by Hot Press Sintering (HPS)
Authors: Rim Saet Byol , Kim Kyeong Il , Hong Tae Whan , Jung Mie Won
Published: August 2011

The Al2O3-CuO-ZnO (ACZ) was synthesized from sol-gel process with aluminum isopropoxide, copper (II) nitrate hemi pentahydrate, Zn (II) nitrate hexahydrate and primary distilled water. The ACZ synthesized powders were analyzed by TG/DTA, XRD, BET and FE-SEM. The ACZ-Co composites membrane was prepared by hot press sintering (HPS). Hydrogen permeability was characterized by Sievert's type hydrogen permeation membrane equipment. The hydrogen permeation rate was measured 0.0496 mol m-2 s-1 at room temperature under 2 bar of H2 atmosphere.
Fabrications and Evaluations of Hydrogen Capacities on MgHX-Transition Metal Oxide(TMO) Composites by Mechanical Alloying
Authors: Lee Jung Il , Kim Kyeong Il , Yoo Sung Woong , Lee Young Geun , Kim Whan Gi , Jung Mie Won , Hong Tae Whan
Published: August 2011

Hydrogen energy had recognized clean systems and high energy carrier. Mg and Mg-based materials have been lightweight and low cost materials which had been 7.6wt.% hydrogen capacity. However, Mg and Mg-alloys were currently hinder by its high absorption/desorption temperature, and very slow reaction kinetics. Therefore, one of the most methods to improve kinetics focused on addition transition metal oxide. Addition to transition metal oxide in MgHxpowder produce MgHx-metal oxide composition by mechanical alloy and it analyze XRD, EDS, TG/DSC, SEM, and PCI. This report considers kinetics by transition metal oxide rate and hydrogen pressure. In this research, we can see behavior of hydriding/dehydriding profiles by addition catalyst (transition metal oxide). MgHx-5wt.%Fe2O3composite was measured most high hydrogen capacity and fast kinetics.
Study on the Artificial Lightweight Aggregate by Using Reject Ash, Dredged Soil, and Ferrous Materials
Authors: Kim Yoo Taek , Choi Yun Jae , Jang Chang Sub , Joo Hyun Jong
Published: August 2011

The dependence of composition and sintering temperature on physical properties of ALA was investigated. Mechanism of black discoloration(sometimes called black core) usually found in the interior cores of artificial lightweight aggregate was also investigated by the optical observations. As a result, the primary cause of black discoloration in the interior of the lightweight aggregate body resulting from incomplete burn-out of carbonaceous impurities and iron-containing materials.In the cross-sectional morphology of ALA, bloating phenomena as well as formation of large pores were found in the samples containing ferrous materials. By increasing content of ferrous materials, both specific gravity and water absorption have been decreased.
Synthesis and Formation Mechanism of Mn-Doped Zn2SiO4 Brown Pigment
Authors: Hwang Dong Ha , Han Kyong Sop , Lee Byung Ha
Published: August 2011

A willemite brown inorganic pigment was synthesized by subsyituting MnO for ZnO. The composition of MnxZn2-xSiO4 (X=0.1, 0.3, 0.5, 0.7 and 0.9mole) was synthesized at 1200~1300°C by solid state method. The characteristics of synthesized pigment were analyzed by X-ray diffraction, FT-IR spectroscopy, Raman spectroscopy and SEM. The UV- vis spectroscopy and CIE L*a*b* measurement were employed to analyzed color. Willemite single crystal phase was synthesized with compositions of Mn0.3Zn1.5SiO2 and Mn0.5Zn1.5 SiO2 from 1300°C/3h. The synthesized pigment of Mn0.5Zn1.5 SiO2 at1300°C/3h was applicated to lime barium glaze and lime zinc glaze and the CIE L*a*b* values were 30.32, 7.17, 3.14 and 32.04, 8.18, 3.49, respectively.
Synthesis of Co-Doped Tialite Ceramic Pigments and Coloring in Glazes
Authors: Kim Yeon Ju , Han Kyong Sop , Lee Byung Ha
Published: August 2011

Synthesis of gray ceramic pigment was carried out by doping cobalt on Tialite crystal structure. Tialite was synthesized by using Al2O3 and TiO2, and was doped with Co3O4 as a chromophore material. To prevent the thermal decomposition during cooling procedure Fe2O3 was added by 0.05mole as a stabilizer. Samples were fired at 1400~1500°C for 2hours and cooled naturally. Crystal structure, solubility limit and color of synthesized pigment were analyzed by XRD, Raman spectroscopy, UV and UV-vis. Yield percentage of Tialite was 96.15% with using Fe2O3 as a stabilizer. It was found that solubility limit of Co2+ in Tialite crystal was 0.03 mole% through analysis of XRD and Raman. By adding pigment with 0.03 mole% of Co2+ to lime-barium glaze, stabilized Dark Gray color glaze having 46.12, -1.26, 0.53 as CIE-L*a*b* was synthesized.
Synthesis of Perovskite Brown Pigments
Authors: Joo In Don , Han Kyong Sop , Lee Byung Ha
Published: August 2011

This study aims to synthesize Cr doped Perovskite brown pigments. The pigment were synthesized by doping Cr2O3(0.01 ~ 0.05mole) for TiO2(0.993 ~ 0.963 mole) at 1150 ~ 1350°C. The samples were characterized by X-ray diffraction (XRD), Raman Spectrometer, Scanning Electron Microscope(SEM) and the UV/Vis spectroscopy. The optimum composition was CaCr0.03Ti0.978O3and heating condition was 1300°C for 3h of soaking time. The doped Cr ion for Perovskite was observed to be Cr(Ⅲ) and Cr(Ⅳ). The brown color was mixed with violet doped by Cr4+(3A2 → 3T2) and Blueish-Green doped by Cr3+(4A2g → 4F1g). The results of SEM analysis showed the Perovskite structure and the particle size was approximately 2µm. The color in Frit 6060 glaze adding 10wt% pigment was Redish Brown, and CIE Lab parameters were L*= 41.53, a*=13.27 and b*=9.94 .
Effects of Strain Rate in Cold-Rolled Pure Copper Produced by Different Rolling Processes
Authors: Song Kuk Hyun , Kim Han Sol , Kim Won Yong
Published: August 2011

To evaluate the microstructures and mechanical properties in cross-roll rolled pure copper, comparing with conventionally rolled materials, this work was carried out. Pure copper (99.99 mass%) sheets with thickness of 5 mm were cold rolled to 90% thickness reduction by cross-roll rolling (CRR) and subsequently annealed at 400 °C for 30 min. Also, to analyze the grain boundary character distributions (GBCDs), electron back-scattered diffraction (EBSD) technique was employed. As a result, the cold rolled and annealed materials consisted of significantly refined grains than that of the initial material (100 mm). Especially, the CRR processed material showed more refined grain size (6.5 mm) in average than that (9.8 mm) of conventional rolling (CR). These grain refinements directly affected an increase in mechanical properties. Therefore, the microstructural and mechanical properties development observed in both processes was systematically discussed in terms of the effective strain originated by the plastic deformation.
Preparation of SiC Whiskers by Microwave Heating
Authors: Kuang Jian Lei , Li Li , Cao Wen Bin
Published: August 2011

Silica-sol and activated carbon were used to prepare SiC whiskers by microwave heating. The effect of packing density of raw material powders on the morphologies of SiC whiskers has been investigated. It was argued that by decreasing the packing density of raw material powders, the growing space of the SiC whiskers increases and the morphologies of the whiskers changes from flexural to straight along with the increase in length. When the packing density was lower than 0.26 g/cm3, straight and dispersal SiC whiskers with high slenderness ratio could be obtained.
Synthesis and Characterization of Block Copolymer from Natural Rubber, Toluene-2,4-Diisocyanate and Poly(ξ-aprolactone) Diol-Based Polyurethane
Authors: Panwiriyarat Wannarat , Tanrattanakul Varaporn , Pilard Jean François , Khaokong Chuanpit
Published: August 2011

A new type of polyurethane (PU) has been synthesized by using hydroxyl terminated liquid natural rubber (HTNR) and poly(e-caprolactone) (PCL) as a soft segment and toluene-2,4 diisocyanate (TDI) as a hard segment. This PU becomes a biodegradable and recyclable polymer. The PU samples were synthesized by solution polymerization. TDI/PCL polymerization was prepared in order to determine the appropriate NCO:OH ratio which evaluated from the molecular weight of derived PU and the ratios which were able to form a polymeric film. The suitable NCO:OH ratios were 0.84:1 – 1.20:1 and the Mn of the derived PUs was 3000-5500 g/mol determined by using GPC. PU from PCL-HTNR block copolymer was synthesized by varying molar ratio between PCL and HTNR. HTNR has been synthesized by epoxidation reaction and chain cleavage of natural rubber. The Mn of HTNR was in the range of 1700-8000 g/mol. 1H-NMR and FTIR were used to determine the functional group in order to verify the prepared HTNR and PU. Glass transition temperature and thermal decomposition of PU samples were investigated by using DSC and TGA, respectively.
A Homogeneous Solidification Criterion for Undercooled Ni-20at%Pb Hypermonotectic Melts
Authors: Xie Hui , Yang Gen Cang , Jia Lei , Lu Zhen Lin
Published: August 2011

The kinetic process of liquid-liquid phase separation in the undercooled Ni-20at%Pb hypermonotectic alloy melts was analyzed theoretically. The results showed that liquid-liquid separation could not be inhibited due to smaller nucleation barrier and bigger nucleation rate of Pb-rich droplets. In the course of liquid-liquid phase separation, the volume fraction of Pb-rich droplets was thought as a function of time or temperature. At a certain cooling rate, the volume fraction was mainly controlled by the undercooling of Ni-Pb hypermonotectic melts. Based on the above results, a homogeneous solidification criterion for the undercooled Ni-20at%Pb hypermonotectic alloy melts was developed. Such a criterion predicted that the homogeneous microstructure could be obtained at the undercooling 263K, and the experimental results accorded with the predicting ones on the whole.
Oxidation Behavior of As-Forged Fe-25wt%Cr Alloys at 1100°C in Air
Authors: Xie Hui , Jia Lei , Zhang Xiao Feng , Lu Zhen Lin
Published: August 2011

Fe-25wt%Cr alloys were fabricated by combining Powder Metallurgy (PM) with hot-forging treatment, and their oxidation behavior at 1100°C in air was investigated systematically by using XRD, SEM and EDS, respectively. The results showed that a composite oxidation scale containing both Cr2O3and FeCr2O4formed on the surface of as-forged Fe-25wt%Cr alloys after oxidation at 1100°C in air for 100 hours. The oxidation process of Fe-Cr alloys could be obviously divided into two different stages, and the kinetics of two-stage oxidation agreed well with the parabolic law. The first could be corresponding to the formation of protective Cr2O3layer, while the second could be thought as the growth of FeCr2O4and the further oxidation of the inner Cr2O3oxidation scale. The faster oxidation rate in the second stage could be attributed to both the diffusion of iron ions rapider than that of Cr in the Cr2O3layer and the fast transport velocity of oxygen ions along the cracks.
Hydrogen Variation in Molten Steel during LF Refining
Authors: Ju Jian Tao , Lu Zhen Lin , Zhang Min Juan , Zhang Zhao Hui , Yang Jun
Published: August 2011

The hydrogen content was measured by HYDRIS hydrogen analyzer during ladle furnace (LF) refining process aiming to test the regular pattern of hydrogen variation in molten steel. The results showed that the hydrogen increased during temperature rising, Ca-treatment and soft blowing argon period, and the absolute increment were 0.64 ppm and 0.46 ppm respectively. The water in refining slag and submerged arc slag led to hydrogen increase during temperature rising period, and fast wire-feeding speed led to hydrogen increase during Ca-treatment and soft argon blowing period. In addition, during the desulfuration and alloying period, excessive large argon blowing caused the hydrogen content increasing by 0.22 ppm.
Oxidation Behaviors of Pure Ti Thermal Plasma Spray Coated Mo-Si-B Alloys
Authors: Song Young Ho , Park Joon Sik , Kim Jeong Min , Yi Seong Hoon
Published: August 2011

Mo-Si-B alloys have been received an attention due to the high temperature strength and phase stability. However, the nature of poor oxidation resistance often limits the application of the alloy system. The unstable MoO3 phase is naturally produced when the alloys were exposed at low and /or high temperature in an air atmosphere. In order to resolve the poor oxidation resistance of the alloy system, several attempts have been made via surface coatings and/or component additions. In this study, the oxidation behaviors of the Ti powder thermal spray coated Mo-Si-B alloys have been investigated in order to identify the underlying mechanism for the effect of precursor Ti coatings on Mo-Si-B alloys. The oxidation tests performed at 1100 °C show that the Ti powder was tightly bonded and reacted with the surface of the substrate, and TiO2 layer was formed at the outer surface of the coated Ti layer as a result of oxidation exposure. The oxidation behaviors of pure elemental component coated Mo-Si-B alloys have been discussed in terms of microstructural observations during oxidation tests.
Esterification of Chemical Functional Single-Wall Carbon Nanotubes
Authors: Xie Xiao Feng , Gao Lian , Sun Jing
Published: August 2011

Two kinds of chemical functional single-wall carbon nanotubes (SWNTs) are covalently coupled into special V-type superstructure by the esterification in pyridine medium. Both SWNTs bundles and individual SWNTs can be bound effectively through the deacidification path. The esterification between different kinds of modified SWNTs takes place on their ends and the crystallinity of SWNTs are well remained during the course. Interestingly, the inclinations between coupled SWNTs are very closely to the ester bond angle (109o18’). Furthermore, the formation mechanism about the peculiar structure has been proposed in the paper. The results suggest that selected connection bonds will determine the different angles of coupled SWNTs.
Development of Carbon Nanotube - Reinforced Silk and Cannabis Fibers by an Electrophoretic Deposition Method
Authors: Veingnon Somjate , Chuminjak Yaowamarn , Kumpika Tewasin , Singjai Pisith
Published: August 2011

Carbon nanotubes (CNTs) were deposited by electrophoretic deposition (EPD) onBombyx mori(silk) andCannabis sativa L. var.sativa (hemp) fibers to improve their mechanical properties. The CNTs were functionalized in mixed acids in order to introduce carboxylic acid groups on their surfaces. The tensile strength and strain at break point of both the modified fibers were approximately two times higher than those of the virgin natural fibers. The addition of small amounts of Mg(NO3)2.6H2O, (CH3COO)2Ni.4H2O significantly improved the deposition of the functionalized CNTs on the hemp fibers.
Constitutive Equation Development for Large Strain Rate Deformation Processing of 2205 Duplex Stainless Steels
Authors: Chen Zhi Yu , Zou De Ning , Liu Huan , Wang Hong Bo
Published: August 2011

Elevated compression tests were conducted on 2205 duplex stainless steel using a Gleeble 3800 thermal simulator under constant strain rates ranging from 0.1 s−1 to 50 s−1 and at deformation temperatures ranging from 900°C to 1200°C for the sample. All tests were performed at a total true strain of 0.9. The elevated temperature deformation behavior of the 2205 duplex stainless steel was characterized based on an analysis of the stress–strain curves. A set of constitutive equations for 2205 duplex stainless steel was proposed by employing hyperbolic sine function. The equations revealed the dependence of flow stress on strain, strain rate and temperature. In order to evaluate the accuracy of the constitutive equations, the mean errors of flow stress between the experimental data and predicted results were calculated. The results showed that there was a good agreement between the prediction and experimental values.