bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhancement of Thermopower due to Deficiency of Sb in FeSb2
Authors: Sanchela Anup V. , Kushwaha Varun , Thakur Ajay. D. , Tomy C.V.
Published: March 2013

FeSb2 was recently found to be a narrow-gap semiconductor with strong electronelectron correlation and a large thermopower at low temperatures. We report measurements of the electrical resistivity, Seebeck coefficient and thermal conductivity between 5 K to 300 K on polycrystalline samples of FeSb2 and FeSb1.9. We found that the deficiency of Sb in the parent compound leads to a giant anomalous peak in thermopower (S) at low temperatures, reaching ~ 426 μV/K at 20 K, resulting in a high thermoelectric power factor at low temperatures, achieving 10 μW/K2m at 27 K.. Consequently, a significantly enhanced thermoelectric figure of merit ZT ~ 0.0015 is achieved near room temperature. At low temperatures there is no improvement in ZT values due to the high thermal conductivity (phonon dominant region). Keywords: Seebeck coefficient, thermal conductivity, resistivity, thermoelectric figure of merit. PACS: 72.20.Pa, 71.27.+a, 71.28.+d
Dielectric Properties of W-Type BaCa2Fe16O27 Hexaferrite Prepared Using a Stearic Acid Gel Route
Authors: Chauhan Chetna C. , Jotania Rajshree B.
Published: March 2013

W-type hexagonal ferrite with composition BaCa2Fe16O27 was prepared using a stearic acid gel method. The precipitate of barium calcium hexaferrite was calcinated at 650°C, 750°C, 850°C and 950°C in a furnace for 4 hours and then slowly cooled to room temperature. The dielectric constants (real Є and imaginary Є), conductivity (σ) and dielectric loss (tan δ) have been measured at room temperature as a function of frequency (102-106 Hz). The dielectric behavior of prepared hexaferrite samples can be explained by the mechanism of polarization and the electrical conduction mechanism is explained by using the electronic hopping model of Heike Johnson.
Growth and Optical Characterization of DVT Grown SnSe0.5Te0.5 Single Crystals
Authors: Patel Rahul B. , Solanki G.K. , Patel Vimal M. , Gosai N.N. , Patel Ruchita R. , Mansur Yunus Gafur
Published: March 2013

In present investigation, we report the growth of SnSe0.5Te0.5single crystals by direct vapor transport (DVT) technique. The main requirement of this technique is precise adjustment of the temperature gradient between two zones of a horizontal furnace to enhance the transport of material in vapour form. For structural characterization, X-ray diffraction technique is used and it is found that this material is crystallized in orthorhombic structure. The values of lattice parameters, unit cell volume and X-ray density are calculated and presented. For optical characterization, absorption spectra of thin flake like crystals have been taken by using UV-VIS-NIR Spectrophotometer in the wave number range 200 nm to 2000 nm at room temperature with the incident plane polarized light beam normal to the basal plane i. e. along the c-axis of the grown flakes of SnSe0.5Te0.5single crystals. Direct as well as indirect band gap has been calculated near the fundamental absorption edge. Optical parameters such as transmittance (T), reflectance (R), refractive index (η) and extinction coefficient (k) have been determined and represented here from the measured value of absorbance of this crystal within said wavelength range.
Preparation and Properties of Thermo-Sensitive Resin for Processless CTP Plate
Authors: Zhang Bao Hua , Cui Hou Li , Xue Xing Wang , Shen Ping Ping , Wan A Jun
Published: March 2013

Computer-to-Plate (CTP) technology has been becoming an important topic of research and application during the era of digital printing. Processless CTP plate is regarded as a leading candidate for CTP plate due to its many merits such as friendly to environment, saving resources, good quality of imaging, low cost and so on. A new thermo-sensitive resin which could be used in processless CTP plate was synthesized by solution polymerization with styrene and N, N-dimethylaminoethyl methacrylate in 1:1 molar ratio using azodiisobutyronitrile (AIBN) as initiator and 1,4-dioxane as solvent and then by hydrogen peroxide (H2O2) oxidation of the tertiary amine groups of the copolymer. It could be found from thermogravimetric analysis that there was a slight weight loss before 120°C owing to water evaporation; and there was an obvious weight loss from 140°C to 230°C owing to the decomposition of amine oxide group; and there was a large weight loss after 300°C owing to the decomposition of thermo-sensitive resin. It was found from contact angle analysis that the contact angle of the thermo-sensitive resin film reached maximum 75° after baking for 7 min at 140°C, which means that the decomposition rate of amine oxide group is slow and parts of amine oxide groups decompose incompletely. The contact angle of the thermo-sensitive resin film reached maximum 80° after baking for 5 min at 160°C or 2 min at 180°C which means that thermal decomposition rate increases with the increase of temperature and the decomposition occurs completely. It was also found that the resin film could be easily washed away from the substrate with neutral water before heat-treatment, but it could no longer be removed after the heat-treatment of baking for 5 min at 140°C or baking for 2 min at 160°C or baking for 1 min at 180°C. This new thermo-sensitive resin could be used in chemical-free thermal laser imaging application.
New EM Transmitter with Y3Fe5O12 Based Magnetic Feeders Potentially Used for Seabed Logging Application
Authors: Niaz Akhtar Majid , Yahya Noorhana , Nasir Nadeem
Published: March 2013

Sea bed logging (SBL) is a new technique for detection of deep target hydrocarbon reservoir. Powerful electromagnetic (EM) transmitter is required for the transmission of EM signal underneath the seabed. New aluminum transmitter with yttrium iron garnet (Y3Fe5O12) based magnetic feeders was used in a scale tank to increase the magnitude of the magnetic field. Yttrium iron garnet samples were prepared using self combustion technique at different sintering temperatures of 750°C, 950°C and 1150°C. Characterizations of Y3Fe5O12 samples were done by using XRD, RAMAN, FESEM and Impedence network analyser. X-ray diffraction results revealed that yttrium iron garnet phase with good crystallinity appeared at sintering temperature of 1150°C. Nanoparticles size ranging from 60 to 110 nm was investigated. Raman results also confirmed garnet structure of yttrium iron garnet at sintering temperature of 1150°C. Field emission scanning electron microscopy (FESEM) was used to image the morphology of the Y3Fe5O12 nanoparticles. Magnetic properties of Y3Fe5O12 magnetic feeders illustrates that Y3Fe5O12 has high Initial permeability (58.054), high Q-factor (59.842) and low loss factor (0.0003) at sintering temperature of 1150°C. Y3Fe5O12 magnetic feeders with high Q factor were chosen for new aluminum EM transmitter. Experiments with a scale factor of 2000 were carried out in scaled tank. It was found that Al transmitter with Y3Fe5O12 magnetic feeders increased magnitude of magnetic field strength up to 180%.
Annealing Effect on the Surface Morphology and Photoluminescence Properties of ZnO Nanorod Prepared by Catalytic-Immersion Method Grown on Si and Au/Si Substrate
Authors: Ab Aziz Azlinda , Khusaimi Zuraida , Abdullah Saifollah , Rusop Mahmood Mohamad
Published: March 2013

ZnO nanorods were prepared by immersion method deposited onto Silicon (Si) and gold-seeded Si (Au/Si) substrate. The annealing temperatures were varied from 400, 500 and 600 °C. The effect of annealing temperature on the surface morphology and photoluminescence characteristics was investigated. The samples were characterized by Field Emission Scanning Electron Microscope (FESEM) to study their morphology and structural properties while the optical properties were characterized at room temperature using Photoluminescence Spectroscope. The shape of ZnO showed growth of nanorods with hexagonal shape. As the annealing temperature increased, the morphology study indicates that particle size of ZnO decreased while the crystallinity increases. The structures has high surface area, is a potential metal oxide nanostructures to be develop for optoelectronic devices and chemical sensors.
Dispersion of TiO2 Nanopowder in the PMMA Matrix Prepared by Sonication-Solution Casting Method
Authors: Hafizah N.N. , Musa Mohamed Zahidi , Mamat Mohamad Hafiz , Rusop Mahmood Mohamad
Published: March 2013

This paper discussed on the structural properties of the PMMA/TiO2 nanocomposite films prepared using sonication-solution casting method. The structural properties of the nanocomposite films were compared by mixing the self-prepared TiO2 (~12 nm) and the commercially available TiO2 (25 nm) in the PMMA. The well dispersion of self-prepared TiO2 nanopowder was observed in the FESEM micrograph. XRD results show that the self-prepared TiO2 nanopowder decrease the crystallinity of the nanocomposite. Further, FTIR reveals that the interaction between the PMMA and TiO2 nanoparticles were detected.
Characterization of CdS Nanoparticles Synthesized Using Microwave-Assisted Polyol Method
Authors: Soltani Nayereh , Saion Elias , Hussein Mohd Zobir , Yunus Robiah Bt. , Navaseri Manizheh
Published: March 2013

Synthesis of cadmium sulfide (CdS) nanoparticles has been performed through the simple and rapid microwave-assisted polyol method, using cadmium chloride and thioacetamide as the cadmium and sulfur sources respectively. Attempts were made to control the size and crystallinity of the CdS nanoparticles by controlling microwave irradiation time and the initial molar ratio of the cadmium and sulfur sources. The structure of nanoparticles characterized by X-ray diffraction (XRD) was hexagonal. No peaks corresponding to impurities were detected, indicating the high purity of the product. The size of the prepared samples was calculated by Debye–Scherrer formula according to XRD spectra. The morphology of particles was observed in the transmission electron microscopy (TEM) images was spherical. The average size of nanoparticles was also estimated from these images. The optical absorption of CdS nanoparticles studied by UV-Visible spectroscopy showed a blue shift from bulk CdS due to quantum confinement. The size of nanoparticles was calculated by Brus formula according to UV-Visible spectrum and compared to XRD and TEM results.
The Effect of Indium Mole Fraction on the Growth Behavior of Your InxGa1-xAs Nanowires (NWs) Grown Using MOCVD
Authors: Othaman Zulkafli , Wibowo Edy , Sakrani Samsudi
Published: March 2013

InxGa1-xAs NWs have been grown with various indium mole fractions (x) using MOCVD. The morphology of InxGa1-xAs NWs was observed using Field Emission-Scanning Electron Microscopy (FE-SEM) in order to study the growth behavior of the NWs. FE-SEM results show that the NWs growth mechanism has changed due to changing of indium mole fraction. At low indium mole fraction, the NWs grew via direct impinging mechanism which has produced NWs with relatively uniform diameter. By increasing the value of x the growth mechanism has transformed to the combination of direct impinging and diffusion of source atoms from the surface of substrate causing tapering of NWs. The degree of tapering increases with increasing value of indium mole fraction. InxGa1-xAs NW grown at x = 0.65 has the highest tapering factor, TF = 12.82, whereas NW grown at x = 0.41 has the lowest tapering factor, TF = 2.76.
Structural, Optical and Electrical Characteristics of Polycrystalline ZnO Thin Film Prepared by Sol-Gel Spin-Coating Method
Authors: Mamat Mohamad Hafiz , Halim A.A.A. , Sahdan Mohd Zainizan , Amizam S. , Khusaimi Zuraida , Rusop Mohamad
Published: March 2013

The effect of annealing temperatures on the Zinc Oxide (ZnO) thin films properties has been investigated. 1.0 M ZnO solution was prepared by sol-gel method as coating solution for ZnO thin films deposition process. The thin films deposition was conducted by spin-coating technique on the silicon and glass substrates. The scanning electron microscopy (SEM) images reveal the evolution of ZnO surface morphology with annealing temperatures. The crystallinity improvement occurred at higher annealing temperature as shown by x-ray diffraction (XRD) result. The optical properties found to be varied at different annealing temperatures. The current-voltage (I-V) measurement results suggested the improvement of ZnO thin film electrical properties with annealing temperatures.
Effect of Temperature on Conductivity Studies of Cellulose Acetate Based Polymer Electrolytes
Authors: Md Ali Ruslinda , Harun Nurhana Ilmira , Ali Ab Malik Marwan , Yahya Mohamad Faizul
Published: March 2013

This paper presents cellulose acetate (CA) - ammonium tetrafluoroborate (NH4BF4) salt complexes films via solution cast technique. The relationship between ionic conduction and the glass transition temperature was investigated in selected cellulose-salt complexes via electrical impedance spectroscopy (EIS) and differential scanning calorimetry (DSC). The thermal study of the films has also investigated using thermogravimetric analysis (TGA).
Zinc Oxide Buffer Layer Insertion for Sensitivity Improvement in Aluminium-Doped Zinc Oxide-Based Humidity Sensors
Authors: Md Sin Nor Diyana , Musa Mohamed Zahidi , Mamat Mohamad Hafiz , Ahmad S. , Aziz A. Abdul , Rusop Mahmood Mohamad
Published: March 2013

The improvement of sensitivity toward humidity by insertion of buffer layer has been investigated. The insertion of hetero- or homo-buffer layer of zinc oxide (ZnO) thin film before deposition of high quality ZnO had been reported for the growth on highly mismatched substrate. Three samples are characterized with different properties which are as deposited ZnO thin film without buffer layer (as deposited ZnO thin film) , anneal ZnO thin film without buffer layer (ZnO thin film) and anneal ZnO thin film with buffer layer (ZnO/ AZO thin film). The structural properties of ZnO thin film has been characterized field emission scanning electron microscopy (FESEM) JEOL JSM 6701F, atomic force microscope AFM (Park System XE-100) and XRD (Rigaku Ultima IV). The electrical and optical properties has been characterized using 2 point probe I-V measurement (Keithley 2400) and UV-Vis spectrophotometer (JASCO 670) respectively. In this work, we have focused on investigating the humidity sensitivity of ZnO thin film deposited using RF magnetron sputtering (SNTEK RSP 5004-PVD) with and without the buffer layer (Aluminum-doped ZnO (AZO)) for humidity sensor application.
Photovoltaic Characteristics of Hybrid MEH-PPV and TiO2 Nanoparticle Based Organic Solar Cells
Authors: Zahid Fazlinashatul Suhaidah , Saad Puteri Sarah Mohamad , Musa Mohamed Zahidi , Rusop Mahmood Mohamad
Published: March 2013

The photovoltaic properties of organic solar cells based on hybrid poly [2-methoxy-5-(2-ethylhexyloxy-p-phenylenevinylen) (MEH-PPV) and anatase titanium dioxide (TiO2) nanoparticles as a function of TiO2 concentration were investigated. Synthesis of TiO2 nanoparticles was performed by sol-gel immerses heated method and been used as a filler in MEH-PPV polymer matrix. The hybrid MEH-PPV: TiO2 solar cells exhibited increased in light absorption and power conversion efficiency than the pristine organic solar cell. By further optimizing the concentration of TiO2 nanoparticles, the short-circuit current of the hybrid MEH-PPV: TiO2 was reached up to 0.004823 (mA/cm2) and the corresponding power conversion efficiency was 0.000378% was obtained under Air Mass 1.5 illumination which was more than 80% higher compared to the device without TiO2 nanoparticles. This indicates by embedded TiO2 nanoparticles in MEH-PPV matrix encouraging the charge transportation in the active layer of organic solar cells device.
Multi-Walled Carbon Nanotubes by Thermal-CVD Utilizing Palm DHSA as a Precursor
Authors: Zainal N.F.A. , Kudin T.I. Tunku , Azira A.A. , Zain Ahmed A. , Abdullah Saifollah , Rusop Mohamad
Published: March 2013

We illustrated the optimization of the growth of multi-wall carbon nanotubes (MWCNTs) using thermal chemical vapor deposition (CVD). Palm-based dihydrostearic acid (DHSA) which was never been reported as a precursor, was used as the precursor over five different trimetallic catalysts for the growth of MWCNTs. These trimetallic catalysts were prepared by sol-gel method and used to study on the effect of the production of the MWCNTs from palm DHSA. With different catalyst, the characteristics of MWCNTs changes such as diameter and crystallinity which was confirmed by SEM and Raman spectroscopy studies. The trimetallic catalysts give high yield and offer good graphitization of MWCNTs produced from palm DHSA.
Electrical and Structural Properties of TiO2 Thin Film Prepared at Different Annealing Temperatures by Sol-Gel Spin-Coating Method
Authors: Basri M. , Asiah Mohd Nor , bin Ahmad Mohd Khairul , Mamat Mohamad Hafiz , Rusop Mahmood Mohamad
Published: March 2013

Titanium Dioxide (TiO2) thin films have been prepared on glass substrates by using sol-gel method and spin-coating technique. The samples have been annealed at temperatures of 350°C ~ 500oC. The electrical and structural properties of the thin films due to the changes of annealing treatment process were investigated by 2 point probes I-V measurement and X-ray Diffraction (XRD) respectively. The result show that resistivity of the thin film decreased with annealing temperatures. XRD characterization indicates crystalline structure of TiO2 thin films improved as annealed at higher temperatures.
Effect of Yb Substitution in Bi1.6Pb0.4Sr2Ca2-xYbxCu3Oy Superconductor
Authors: Hawa J.S. , Azhan H. , Yahya S.Y.S. , Azman K. , Hidayah H.N. , Norazidah A.W.
Published: March 2013

This paper reports on the results of Yb substitution for Ca on the superconductivity and structural properties of Bi1.6Pb0.4Sr2Ca2-xYbxCu3Oy superconducting samples with x = 0.000, 0.025, 0.050, 0.100 and 0.200 which prepared by coprecipitation (COP) method. The samples were characterized by X-ray diffraction (XRD), field-emission scanning electron (FESEM), electrical and resistivity measurement by four-probe method. It was found that the substitution of Yb decreased the critical temperature (Tc zero), critical current density (Jc) and volume fraction of Bi-2223 phase. The samples have Tc zero in the range 77 to 100 K. Tc zero gradually decreased with an increase in Yb concentration, corresponding to small change of the carrier concentration. Jc was measured to be 5.7512 A/cm2 for pure sample and decreased to 4.1910 A/cm2 for x = 0.025 at 77 K. The crystallographic structure was found to change slightly from tetragonal to orthorhombic in Yb substituted samples. The lattice parameter c of Yb samples decreased due to the incorporation of Yb3+ (0.858 Å) with smaller ionic size compare to Ca2+ (0.99 Å). From the SEM observation, the grain connectivity became weak with smaller plate-like grain for x > 0.025 Yb concentration resulting in the decreased of Jc.
Surface Morphology, Structural, and Bonding Characteristic of Carbon Nanotubes for In Vitro Culture Applications
Authors: Nurulhuda Ismail , Johari Mohd Amri , Mazatulikhma Mat Zain , Rusop Mohamad
Published: March 2013

In this paper, carbon nanotubes were characterized by several characterization methods such as FESEM (field emission scanning electron microscopy), Raman spectroscopy and fourier transform infrared (FTIR) spectroscopy. FESEM is used to characterize the morphology of carbon nanotubes, the structural is characterize by raman spectroscopy and bonding characteristic is determine by FTIR. The morphology of CNTs is found to be multiwall carbon nanotubes with diameter around 30-50 nm. D-peak was observed at 1341 Cm-1 and G-peak at 1575 Cm-1 based on raman spectroscopy result. The chemical bonding observed at range 2400 - 400 from FTIR spectra. These CNTs will be used for in vitro study in future.
Thermal Stability and Decay Resistance Properties of Tropical Wood Polymer Nanocomposites (WPNC)
Authors: Islam Md. Saiful , Hamdan Sinin , Rusop Mohamad , Rahman Md. Rezaur
Published: March 2013

The effects of nanoclay on the thermal stability and decay resistance properties of tropical wood polymer nanocomposites (WPNCs) were investigated in this work. WPNC were prepared from several selected tropical wood species by impregnating the selected woods with a combination of nanoclay and phenol formaldehyde (PF) prepolymer mixture. The formation of WPNC was confirmed by the fourier transform infrared spectroscopy (FTIR) analysis. Thermal property of manufactured WPNC in terms of thermogravimetric analysis (TGA) was evaluated, and an improvement in thermal stability was found for fabricated WPNC. The wood was then exposed to two types of fungi; white-rot (polyporous versicolor) and brown-rot (postia placenta), for 12 weeks. Decay was assessed through percentage (%) of weight loss. A significant improvement was found in the treated woods compared to the untreated ones. In addition, the fabricated WPNC showed lower moisture content compared with raw one.
Growth of Zinc Oxide Rods in Different Heating Medium
Authors: Khusaimi Zuraida , Amizam S. , Mamat Mohamad Hafiz , Sahdan Mohd Zainizan , Abdullah Norbani , Abdullah Saifollah , Rusop Mohamad
Published: March 2013

In this investigation, it was successfully shown that variation of heating media for infused substrates in precursor solution, affects the growth density and size of nanostructured ZnO rods. ZnO rods were prepared by precipitation on a template of cleaned p-type silicon wafer, sputter-coated with a thin layer of gold, infused in prepared precursor solution. The precursor solution consists of 0.01M zinc nitrate hexahydrate (Zn(NO3)2.6H2O) added with equal concentration of stabilizer hexamethylenetetramine, C6H12N4 (HMTA). The set-up was heated in water-bath or dry-oven at a constant low temperature of 80°C. Structural images of the prepared ZnO rods were captured using scanning electron microscope (SEM), its structural phase orientation was characterized by x-ray diffraction (XRD) and its optical property was analyzed from photoluminescence (PL) emission spectra.
Effect of Precursor Concentration in the Synthesization of ZnO Nanostructures by Solution-Immersion Method
Authors: Ab Aziz Azlinda , Khusaimi Zuraida , Rusop Mahmood Mohamad
Published: March 2013

The effect of precursor concentration ranging from 0.1 to 0.5 M using the mixture of zinc nitrate hexahydrate (Zn(NO3)2.6H2O) and urea (CH4N2O) at 60 oC evaluated in this study. ZnO nanostructures have been prepared by solution immersion method on gold-seeded silicon substrate (Si/Au). Solution immersion method was adopted with the intention to develop a large area deposition at low-temperature benign method of preparation. As concentration increase, the morphologies are seemingly changed from rod (~300 nm) to accumulated nanosheets that consist of many pores. The structural and optical effect of changing the precursor concentration on the synthesization of ZnO films were investigated by X-ray diffractometer (XRD) and room temperature photoluminescence (PL) measurement, respectively. A unique development of size and growth orientation is seemingly affected by the change of the precursor concentration.
The Effect of Inoculum in the Preparation of Fermented Tapioca for Nanotechnology Applications Based on FT-IR Studies
Authors: Nuraini M.Z. , Aishah S. , Nik S.F. , Rusop Mohamad
Published: March 2013

Fermented tapioca which is a new starting material was used as a carbon precursor. Carbon nanotubes (CNTs) were deposited on silicon wafer (Si) by Thermal Chemical Vapor Deposition (TCVD). The gas flow of Argon (Ar) was constant at 70 bubbles per minute and 20 minutes of deposition time. Before the deposition process, silicon was coated with Nickel using spin coater. Various parameters such as amount of inoculums have been studied. Chemical functional groups of carbon nanotubes were characterized using FT-IR Spectroscopy. The FT-IR result shows peaks attributed to multi–walled carbon nanotubes (MWCNT) vibration modes.
Ultra-Violet Photoresponse Characteristics of Nanostructured Al Doped Zinc Oxide Thin Films Based Ultra-Violet Sensor
Authors: Muhamed S.Z. , Mamat Mohamad Hafiz , Md Sin N.D. , Rusop Mohamad
Published: March 2013

Nanostructured Aluminum (Al) doped Zinc Oxide (ZnO) thin films based ultra-violet (UV) sensors were prepared on glass substrates using immersion technique at different immersion times. Surface morphology results as characterized by scanning electron microscope (SEM) show that all prepared nanostructured Al doped ZnO were in form of nanorod structures with the typical diameter in the range of 60-250nm and the length within several micrometers. Photocurrent measurement results of the fabricated UV photoconductive sensor from nanostructured Al doped ZnO thin film immersed at 1 hr gives the highest photocurrent intensity compared with other samples.
Photocatalytic Degradation of Indigo Carmine by ZnO-Cu2O/Graphene Oxide Composites Synthesized via Hydrothermal Method
Authors: Wu Huai Di , Chen Lu Sheng , Hu Jin Chao
Published: March 2013

In this work, ZnO–Cu2O/graphene oxide (GO) composites have been synthesized by using simple hydrothermal method. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to characterize the crystal structure and composite elements. The photocatalytic activity of the composites has been conducted by measuring the degradation of indigo carmine under UV irradiation. When the atom ratio of Zn/Cu is 5/2, 120 °C of hydrothermal synthesis temperature and 20 h of synthesis time, the ZnO/Cu2O/GO composite exhibits good photocatalytic activity with 96.5% degradation rate of indigo carmine aqueous solution under 500 W high pressure Hg lamp irradiation for 240 min.
Preparation and Photocatalytic Activity of TiO2/Opal Composite
Authors: Li Qing Shan , Zhan Biao , Hong Wei , Xing Guang Zhong
Published: March 2013

Opal as a carrier, tetrabutyl titanate as a titanium source, TiO2 loaded on opal was prepared by sol-gel technique. The photocatalysts were characterized by XRD, TEM and UV-VIS absorption spectrum. Their photocatalytic activities were examined by the photocatalytic decolorization of methylene blue solution under UV light irradiation. The effects of calcination temperature, the amount of TiO2 loading and pH on photocatalytic activities were discussed. The results show that TiO2 supported on opal induced enhancement of photocatalytic decolorization rant and TiO2 doping is about 30 wt. % with 92.15% of decolorization rate at 700°C.
The Preparation and Dielectric Properties of BT/PANI/PVDF Composite
Authors: Yang Xiao Jun , Li Jian Yong , Lei Yong Ping
Published: March 2013

Polyaniline (PANI) coated nano-sized BaTiO3 (BT) was blended with PVDF to form BT/PANI/PVDF composite. The incorporation of conductive PANI to the ceramic-polymer systems has significant influence on the dielectric properties of BT/PANI/PVDF composite. The BT/PANI/PVDF composite has higher dielectric constant than the comparable BT/PVDF in the frequency range from 40Hz to 1MHz. The polarization mechanism of the BT/PANI/PVDF composite has been discussed based on the experimental results.
Structure and Properties Evolution of Nanostructed AgBr/TiO2 Visible Light Photocatalyst in Cyclic Running
Authors: Qin Le Wei , He Ke Feng , Chen Wan Ping
Published: March 2013

Nanostructured AgBr/TiO2 visible light photocatalyst was prepared through deposition-precipitation method with AgNO3, KBr and Ti(OBu )4 as the precursors. Though the photocatalyst showed a relatively high photocatalytic efficiency for degradation of methyl orange in water under visible light irradiation in the first cycle, its efficiency was obviously decreased in the subsequent cycles. X-ray diffraction indicated that there existed a dramatic crystalline growth of AgBr in the AgBr /TiO2 nanocomposite after visible light irradiation, which must increase the recombination rate of photo-generated electrons and holes and be responsible for the observed decrease in photocatalytic efficiency. Photo-induced crystalline growth of AgBr may be a limiting factor for the lifetime of AgBr/TiO2 visible light photocatalyst and more attention should be paid to it.
Preparation of Aerogel-Modified Expanded Perlite and its Application in Heat Insulation Coating
Authors: Peng Kang , Yang Hua Ming
Published: March 2013

Building insulation is an important part of building energy conservation. The heat insulation coating preapred from modified expanded perlite has been a potential building thermal insulation material. In this paper, aerogel was filled into the pores of expanded perlite by vacuum impregnation method to produce aerogel-modified expanded perlite at ambient pressure. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and N2 adsorption–desorption techniques. The results revealed that aerogel could be well filled into the pores of expanded perlite, and the resultant aerogel-modified expanded perlite possessed nanoporous structure with higher specific surface area of 196 m2·g-1, and low thermal conductivity of 0.063 W·m-1·K-1 less than that of expanded perlite by 13.3%. Heat insulation coatings prepared from aerogel-modified expanded perlite had good thermal insulation effect, indicating that the product showed potential aplication in the field of building energy conservation.
Preparation and Study of Spherical Nickel Hydroxide Coated by Cobalt Oxy-Hydroxide
Authors: Hou Xin Gang , Liu Wen Wu , Li Cai Xia , Wang You Fu
Published: March 2013

Nanometer nickel hydroxide particles coated by cobalt oxy-hydroxide are prepared through chemical precipitation method. The properties of coated Ni(OH)2 particles is characterized by using X-ray diffraction, scanning electron microscopy, constant current charge/discharge test and cyclic voltammetry. Studies are focused on the effects of different amounts of cobalt oxy-hydroxide on structure and electrochemical characteristics of nickel hydroxide. The results show that a structure of β-Ni(OH)2 is preserved and 2.5 wt % CoOOH can form a well distributed conductive network on the surface of nickel hydroxide particles, thereby leading to higher utilization of active material; Compared to other electrodes, the electrodes with 2.5 wt % coated CoOOH show higher specific capacity and better cycling durability, and the electrodes also has better reversibility of the Ni(OH)2/NiOOH redox couple, and higher oxygen evolution potential.
Modeling and Control for GMA Based on Hammerstein Model Structure
Authors: Liu Qing Song , Zhang Zhen , Mao J.Q.
Published: March 2013

A rate-dependent hysteresis model for Giant Magnetostrictive Actuator (GMA) is proposed based on Hammerstein model structure. The Generalized Prandtl-Ishlinskii (GPI) model is used to represent nonlinear block in Hammerstein model. The validity of model is examined by comparsion between simulation results and experimental data. Based on the proposed model, a PID feedback controller combined with an inverse compensation in the feedforward loop is used for tracking control. Experimental results show that the control strategy is effective.
Stiffness Analysis of a Novel Hybrid Manipulator for Mould Repairing Based on ANSYS
Authors: Li Zhen Shan , Li Yong Gang , Zhang Er Jiang
Published: March 2013

The finite element model of a novel 5-dof mould repairing hybrid machine tool is modeled by using the ANSYS Parametric Design Language (APDL), and the static stiffness of the whole machine and the sensitivity are analyzed. With the help of APDL and the concept of substructure integration, the fast reconstruction strategy to establish the finite element model is put forward. Then, the implementation strategy aimed to analyze the static stiffness of the whole machine and optimize the hinge structure are proposed. Then through the data statistics and the sensitivity analysis, the influence tendency of key flexible components affecting the static stiffness of the system are identified, which provides the guidance for parameter design of this prototype machine.
Water-Soluble Substance: Characteristics and Effects on the Properties of Natural Rubber Latex
Authors: Fan Long Fei , Liao Shuang Quan , Li Chao Qun , Liao Xiao Xue , Guo Ming Wan
Published: March 2013

Water-soluble substance is an important part of non-rubber substance in natural rubber latex and it has significant influence on the properties of natural rubber. The aim of this paper is mainly to study the composition of small-molecular-weight water-soluble substance (s-WSS) and its effects on the properties of natural rubber films. The analysis of IR and HPLC-MS showed that s-WSS (not including sugar) is composed of C3H4N4O6, C7H14O6, C11H13N3O5, C11H20O7 and C6H22N8. While the main component of s-WSS is C7H14O6 whichis a kind of alcohol. The tensile strength of the prepared composites can be increased at low loading of s-WSS. The tear strength of the prepared composites can be improved by adding s-WSS into natural rubber. The thermal oxidation degradation process of the samples has two stages. Compared with neat natural rubber latex, the initial degradation temperature was decreased significantly in both stages when s-WSS was added. While the degradation temperature range became larger in both stages.
Experimental Research on Stress-Strain Curve of Carbon Fiber Reinforced Concrete
Authors: Wang Xiao Chu , Wang Jun Wei , Liu Hong Tao
Published: March 2013

In order to further investigate the stress-strain curve of carbon fiber reinforced concrete, the curve of stress-strain is used segmentation tabulators on the basis of the existing tests. Based on the axial compression experiments of 9 carbon fiber concrete reinforced samples filled with different carbon fiber admixture amounts, the theoretical calculating formula of the stress-strain curve with different admixture amounts was proposed, and the theoretical formula of calculation parameters and carbon fiber volume fraction was putted forward. The experimental results show that the calculation parameters of the stress-strain curve increases with the increase of the carbon fiber admixture amounts. The theoretical calculating formula of the peak strain and carbon fiber volume fraction, the compressive strength, and the calculated results agreed well with the experimental results.
Experimental Study on the Viscoelastic Properties of Asphalt Concrete under Chloride Corrosion
Authors: Zhou Jin Zhi , Dai Jie , Zheng Jian Hua
Published: March 2013

In the paper, uniaxial compression creep tests were carried out at 25°C after the asphalt concrete corroded by different chloride solution concentrations, suffering different times of diurnal temperature variation cycle. Creep stiffness module and the ratio of residual strain were employed to evaluate the viscoelastic properties of asphalt concrete. According to the winter in Wuhan district, the viscoelastic properties of asphalt concrete under the action of chloride corrosion together with day-night cycle were preliminarily studied, and the corresponding viscoelastic parameters were determined with the help of Burgers model. The results show that chloride corrosion and day-night cycle can separately affect the viscoelastic properties of asphalt concrete, and the influence becomes severer while they act together.
Sintering of Ultrahigh Density and Highly Conductive ZnO-Ga2O3 Ceramic Targets
Authors: Liu Cun Qi , Zhang Zhong Jian , Gao Ling , Xiao Chao , Yang Hai Tao
Published: March 2013

The ultrahigh density Gallium (Ga2O3 1 wt%) doped zinc oxide (ZnO, 99wt%) targets were prepared by air sintering. The relative density, conductivity, bending strength, Vickers hardness and shrinkage ratio of GZO targets were measured. The morphologies and microstructures were characterized by XRD and SEM. It turns out that sintered GZO targets achieved a relative density of 98%, square resistance of 7Ω/□, Vickers hardness of 310HV and a bending strength of 90.79MPa. The best sintering temperature is 1300°C. The Ga2O3 added can effectively enter into the ZnO lattice structure to form solid solution during sintering. The second phase of GaZn2O4 turned out when the sintering temperature was 1350°C.
p-Type Field Effect Transistor and UV-Photoconductive Characteristics of Na Doped ZnMgO Thin Films
Authors: Xue Ya , He Hai Ping , Ye Zhi Zhen
Published: March 2013

In this study, the authors have presented results for fabricated ZnO based FET and the UV-photoconductive characteristics of Na doped ZnMgO thin ﬁlms. The electrical measurements confirmed that the conductivity of the Na doped ZnMgO thin ﬁlm is p-type, and the carrier mobility was estimated to be 2.3 cm2V-1S-1. Moreover, after exposed to the 365 nm ultraviolet light, the Na doped ZnMgO thin ﬁlms still exhibited p-type behavior under gate voltage ranging from -5 to 2 V, and the Id increased a little while the carrier mobility did not change much. The photocurrent was measured under a bias of 6 V in air at room temperature. The films performed a higher current intensity after the illumination. The instantaneous rise of the photocurrent was completed when exposed to the 365 nm ultraviolet for 20 s, after switching the ultraviolet off the photocurrent decayed in a slower rate. The enhance rate of photocurrent was about 1.33 %. Conclusively, Na is a considerable acceptor dopant for making high quality p-type ZnO films, and the tiny change in the photocurrent of p-type Na doped ZnMgO thin ﬁlm made it relatively stable when fabricating LEDs and other optoelectronic devices.
Room Temperature Magnetoelectric Coupling in Bi5Ti3FeO15 Ceramics
Authors: Chen X.Q. , Zeng Xiang Bin , Yang F.J. , Kong X.P. , Wei C. , Su P.
Published: March 2013

Magnetoelectric(ME) coupling at room temperature(RT) in four-layered perovskite Bi5Ti3FeO15(BTFO) ceramics prepared by conventional solid state reaction method was observed. Unsaturated ferroelectric hysteresis loop with 2Pr=0.464 μC/cm2 and 2Ec=25 kV/cm at an applied electric field 58 kV/cm was obtained because of lower breakdown voltage which maybe induced by lower relative density of the sample. A weak ferromagnetic (Mr=0.122 memu/g, Hc=69 Oe) rather than an antiferromagnetic property was observed at RT by magnetic measurement. Significantly, the ME coupling between the electric dipoles and magnetic dipoles at RT was demonstrated by measuring the effect of magnetic and DC electric poling on ferroelectric and magnetic hysteresis loops, respectively. Both Pr and Mr decreased after magnetic and DC electric poling. And the rate of Pr change decreased with increasing measuring electric field.
Low Cycle Fatigue Life Prediction of Ti-6Al-4V Titanium Alloy under Multi-Axial Non Proportional Cyclic Loading
Authors: Wang Rui Feng , Li You Tang , An Hu Ping
Published: March 2013

A series multi-axial tension and torsion low cycle fatigue life experiments of Ti-6Al-4V alloy were conducted on the MTS tension and torsion joint testing machine, in which the torsional strain control and non proportional cyclic loading method under the loading paths of circular, rectangular, square, oval and diamond were successively used. The experimental results are compared and analyzed with the results that calculated by the equivalent strain model, the energy method model and the critical plane method model. The results show that the critical plane method is the accurate prediction model to predict the multi-axial low cycle fatigue life of Ti-6Al-4V alloy.
The Study of the Microstructure and Mechanical Properties of Friction Stir Spot Welding Joint between AZ31B Magnesium Alloy and Steel
Authors: Wang Xi Jing , Wu Yu Lian , Zhang Zhong Ke , Guo Ting Kai , Lu Yong Xin , Shi Ji Peng
Published: March 2013

AZ31B magnesium alloy, Rotating tool without pin, Friction Stir Spot Welding, Microstructure, mechanical properties
The Effect of Calcium Treatment on the Corrosion Resistance of Manganese Steels
Authors: Chen Shan , Chen Xue Qun , Zheng Lin , Li Guo Ming , Chang Wan Shun , Cao Guo Liang
Published: March 2013

The metallurgy quality of the steel was improved greatly by calcium treatment which was a technique developed for a long time. The Mn steels treated with calcium, carbon-manganese steels and nickel-chromium steels were collected and their corrosion behaviors were investigated. The results showed that the corrosion resistance of the Mn steel is lower than that of the Ni-Cr steel. The shape of the inclusions can be modified and quality of the steels can be enhanced by the calcium treatment, and the corrosion resistance of the steel treated with calcium is higher than that of the common carbon-Mn steel, and near to that of the NiCr steel.
Characterization of Chemolithoautotrophic Growth Herbaspirillum sp. Isolated from Volcanic Environment in Miyake-Jima Island, Japan
Authors: Lu Hong Sheng , Shi Long Qing
Published: March 2013

A chemolithoautotrophic growth bacterium KP1-50T was isolated from 22-year-old volcanic deposits of Miyake-jima island (Japan) in this study. Its chemolithoautotrophic growth was tested using mineral salt medium (MS) medium under the atmosphere of H2, O2 and CO2. Phenotypic tests were mainly done with API 20NE kit system (bioMérieux). Phylogenetic position was determined by constructing the system tree. Chemolithoautotrophic growth of strain KP1-50T was proved by its growth curve with OD660 value of 0.5. The phylogenetic analysis based on 16S rDNA gene sequences indicated that sequence similarity between this strain and Herbaspirillum seropedicae LMG 6513T was 97%. The major cellular fatty acids are C16:0(31.3%), C16:1w7c/C15:0 2-OH iso (26.5%), C18:1 iso/trans (22.7%). The DNA G+C content of strain KP1-50T was 58mol%. DNA-DNA relatedness between strain KP1-50T and H.seropedicae LMG6513T, H.putei NBRC102406T and H.rubrisubalbicans NBRC102523T were 14.7%, 22.7% and 12.5% respectively. Strain KP1-50T seemed to be a novel species of the genus Herbaspicrillum, its accession number was AB366195 and the name of Herbaspirillum chemorialis sp. nov. was proposed.
Forecasting and Discussing of the Fouling Characteristic of the Plain Tube
Authors: Wen Xiao Qiang , Xu Zhi Ming , Wang Jian Guo , Sun Ling Fang
Published: March 2013

A fouling experimental system was built to measure the following parameters: wall temperatures, input and output temperature, etc. The model was set up based on the partial least-squares regression (PLS) to predict the fouling characteristics of the plain tube, in which there were five input vectors, which were the wall temperature, the inlet and outlet temperature and one output vectors, which was the fouling resistance. The prediction model was validated by the second operation cycle. By comparison of the predicted and experimental results, the maximal relative error of the model was in 8.5%, so, the partial least-squares regression algorithm of fouling model is reasonable and feasible. It provides an effective method for the design and operation personnel to anticipate the heat exchanger fouling characteristics under conditions of known water quality environmental parameters. The four-variable optimization model was obtained by analyzing the impact of each single independent variable on the prediction model, to increase the precision of the model. In addition, analysis of the impact of flow rate, etc. on the prediction model was also given.
Preparation of Ag-C Core-Shell Structure Composite Functional Materials
Authors: Zheng Jing Wu , Wang Zhi Liang , Qiao Liang , Cai Wei , Jiang Li Qiang , Ying Yao , Che Sheng Lei
Published: March 2013

Abstract. This article reports the chemical deposition of silver shells on the surface of micro- carbon spheres. The structure, morphology and composition were characterized by scanning electron microscopy and X-ray diffraction. These result show that: concentrated nitric acid can transform the hydrophily of carbon surface; the application of promoting tin-or silver-containing agents that enhance metallic shell deposition by vigorous redox reaction between Sn2+or Ag+, is important to the site-selective deposition of silver. The resulting thickness of uniform silver shells on the surface of carbon and the crystal size of silver is 24.8nm. Amount of Ag-C core-shell structure composite can be systematically controlled through adding PVP and modest pH value
Nano-Coating Texture on the Shear Slip Surface in Rocky Materials
Authors: Sun Yan , Jiang Shao Yong , Wei Zhou , Lu Xian Cai
Published: March 2013

Through SEM observation from natural and experimental examples of rocky materials, nanocoating texture was found on the shear slip surface (plane, lamellae). Our researching suggested that the nanocoating possesses some textural characteristics including granular, delaminating and rheological one. In general, single nano-sized grain (40-80 nm in diameter) with moderate roundness and sphericity could aggregate into the compound grain, and thickness of the nanocoating (thin shell, film) might reach from μm to cm scale in different rocky materials. Development of the nanocoating textures of shear slip surface could be subdivided into three stages, i.e. strain hardness, strain softening and strain decaying stage, and its forming mechanism is quite similar to the “tribological white layer” which is very common phenomena in metallography. Furthermore, it is determined that the nanocoating lamellae in rocky materials might be capable to constitute a shelter for a reservoir.
Geometrical and Electronic Structure Investigations of S-Doped Graphene
Authors: Bi Dong Mei , Qiao Liang , Hu Xiao Ying , Liu Shu Jie
Published: March 2013

The geometrical and electronic structures of pure graphene and S-doped graphene have been investigated using plane wave pseudopotential method with generalized gradient approximation based on the density functional theory. The local structure change, Mulliken population, density of states, and electron density difference of S-doped graphene have been calculated. It can be observed that the Fermi level shifts towards the conduction band after the doping of sulfur atom. The results also suggest that there are chemical bonds formed between the sulfur and carbon atoms, and the charges transfer from the doped sulfur atom to graphene.
Precision Machining Based on Elastic Waves in Solids
Authors: Chen Xiao Jian , Wu Fei , Jin Jia Mei
Published: March 2013

A grinding tool without kinematic pairs, of compactness and low cost, based on the defect that it is difficult to improve the precision of kinematic pairs of traditional grinding methods, is presented in the paper. The operating principle based on elastic waves was analyzed. The grinding tool would realize the ultra-precision machining theoretically and experimentally. Components of the prototype were manufactured, assembled, and tested for the grinding performance to validate the concepts of the precision machining and confirm the simulation results of modal and harmonic analysis. The test results show that the performance of the proposed grinding tool can meet the requirements of the precision grinding. It is confirmed that this prototype can realize the accurate ultra-low-stress and the removal of material under ultra-low-stress circumstance. The research is aimed at exploring new methods and new theories of ultra-precision surface machining and giving a new solution to the problem of ultra-precision surface machining.