bluuebunny/crossref_metadata_2025 huggingface dataset:
First Principle Study for the Melting Properties of Face-Centred-Cubic Aluminum
Authors: Zhou Lin , Zhang Qing Ming , Ji Guang Fu , Gong Zi Zheng
Published: March 2013

Ab initio electronic structure optimization and total energy calculations for fcc aluminum are used to study the equation of state (EOS).Through fitting to quasi-harmonic Debye model, the thermodynamics properties of different temperatures are calculated. The melting curve at different pressures is presented based on Lindemann measures. The results show that the calculated EOS and the revised melting curve both are in a good agreement with the shock compression and the diamond-anvil-cell (DAC) data. The results illustrate that we can use simple static calculation method which takes less time to gain reasonable melting results. It can be used in the qualitative forecast for materials with difficult experiments.
Beam Assisted Deposition Film for Improving Fretting Fatigue Resistance of Ti-8Al-1Mo-1V Alloy at Elevated Temperature
Authors: Zhang Xiao Hua , Xiang Ding Gen , Liu Dao Xin
Published: March 2013

Ion-beam-assisted deposition (IBAD) was investigated as a potential way to increase the fretting fatigue resistance of Ti-8Al-1Mo-1V alloy at elevated temperature. Three coating systems, hard TiN film with good toughness and soft Al film of low friction and Cu/Ni multilayer films with modulation period thickness of 20~600nm have been applied on the base material. Coefficients of friction and fretting fatigue lives of the specimens with and without film were compared. The film damage was characterized through scanning electron microscopy. The results indicate that the IBAD technique can prepare all films with high bonding strength and excellent lubricating properties. The fretting fatigue life of the Ti-8Al-1Mo-1V alloy with the TiN film was improved by a factor of 2.4 as compared to the uncoated substrate at elevated temperature because of the excellent wear and fatigue resistance and good toughness of the film. Excellent wear resistance and good anti-fatigue properties could be simultaneously obtained by a single hard film to control the fretting fatigue damage. The IBAD Al film significantly improved the fretting fatigue resistance of the Ti-8Al-1Mo-1V alloy at elevated temperature for good lubricating property. The fretting fatigue resistance of the Ti-8Al-1Mo-1V alloy was improved by all the Cu/Ni multilayer films. However, the fretting fatigue resistance did not increase monotonically with the modulation period of the films. Films with a modulation period of 200 nm had the highest fretting fatigue resistance among the multilayer films prepared owing to their high toughness and strength and good lubricating and anti-fatigue action. The fretting fatigue resistance of films with a modulation period of 20 nm was low because of the poor fracture toughness and crack propagation resistance, even though these films had the highest hardness and good fretting wear resistance. Thus, comprehensive properties, including high toughness and strength, must be considered for multilayer films used to improve the fretting fatigue resistance of titanium alloys.
Free Edge Stress Analysis of Unidirectional CFRP Laminates Based on a Homogenization Theory for Time-Dependent Composites
Authors: Goto Keita , Matsuda Tetsuya
Published: March 2013

In this study, distributions of microscopic stress at free edges of unidirectional carbon fiber-reinforced plastic laminates (CFRP laminates) are analyzed three-dimensionally, based on a homogenization theory for time-dependent composites. For this, the homogenization theory is reconstructed for free edge problems using a traction-free boundary condition. Then, an analysis domain is reduced using the point-symmetry of the internal structure of the unidirectional CFRP laminate. Moreover, the substructure method is newly introduced into the theory to reduce the computational costs required for the analysis. The present method is then applied to the elastic-viscoplastic microscopic stress analysis at free edges of unidirectional carbon fiber/epoxy laminates subjected to an in-plane uniaxial tensile load. It is shown that complex microscopic stress distributions occur in the vicinity of the free edge, especially around fiber/matrix interface regions.
Large Deflection of a Pin-Supported Slender Geometrically Asymmetric Sandwich Beam under Transverse Loading
Authors: Zhang Jian Xun , Qin Qing Hua , Ai Wei Long , Wang Zheng Jin , Wang Tie Jun
Published: March 2013

The objective of this work is to study the large deflection of a pin-supported slender geometrically asymmetric metal foam core sandwich beam under transverse loading by a flat punch. Based on the yield criterion for geometrically asymmetric metal foam core sandwich structure, analytical solution for the large deflection of a pin-supported slender sandwich beam is obtained, in which the interaction of bending and stretching induced by large deflection is considered. The finite element results confirm the accuracy of the analytical solutions. The effects of asymmetric factor and boundary condition on the structural response of the asymmetric sandwich beam are discussed in detail. It is shown that the axial stretching induced by large deflection plays an important role in the load-carrying and energy absorption capacities of geometrically asymmetric sandwich structure.
The Collapse Characteristics of CFRP Hat-Shaped Sectional Members under Moisture Absorptions Having the Temperature Change
Authors: Yang Yong Jun , Yang In Young , Choi Ju Ho
Published: March 2013

CFRP composite with light weight, high strength, and high elasticity compared to metal is widely used rather than previous steel plates. However, CFRP composite material has the weakness in hygrothermal and impact collapsed environment. Especially, moisture absorption into composite material under hygrothermal environment can change molecule arrangement and chemical properties. Therefore, the purpose of this study lies in acquiring quantitative design data that can be put into the practice by comparing and evaluating the strength degradation under the environment where the moisture is absorbed by conducting static and impact collapse test after setting extreme condition for CFRP composite that takes consistent form such as frontal side members that is actually used in vehicle. This study compared and studied change in the progress of a moisture absorption ratio after setting up the temperature of 60 degrees, and 80 degrees in order to comprehend how the change in the temperature impacts on moisture absorption status inside CFRP composite materials. As a result of this study showed that the strength reduction of about 50% appears due to moisture absorptions. In addition, it showed that the higher the temperature is, the more rapid the progress of a moisture absorption inside CFRP composite materials is. Accordingly, it showed that the change in matrix also has a weak point.
Design Issues of a Kolsky Tension Bar
Authors: Neves Renato R.V. , Alves Marcilio
Published: March 2013

In general, materials exhibit an increase of strength when loaded at high strain rates, which should be taken into account when dealing with structural impact. Kolsky developed an equipment operating based on elastic wave propagation capable of submitting a material sample to high strain rates. This paper presents some design features of such a tensile wave machine, including mechanical and electronic design issues, which may be helpful in a design phase.
Finite Element and Experimental Study of the Fiber-Reinforced Composite Laminates under Low-Velocity Impact
Authors: Liu Han Yang , Qiu Xin Ming , Zhang Deng Yu , He Yu Huai , Fan Jin Juan
Published: March 2013

Experimental and numerical studies of the 2D woven composite laminates under low-velocity impact with different energy are discussed in this paper. The traditional Hashin failure criteria are improved to cover the failure modes of fiber rupture and delamination. It is found that the damage level depend on the impact energy. The matrix deformation is the main reason of delamination. The simulating results are in good agreement with the experimental phenomenon observed by nondestructive examination (ultrasonic C scanning) and cross-section examination
Effect of Configuration and Target Span on the Ballistic Resistance
Authors: Gupta P.K. , Iqbal M.A. , Tiwari G. , Gupta N.K.
Published: March 2013

Numerical simulations were carried out wherein 20 mm diameter conical nosed projectiles were hit on Weldox 460 E steel targets of varying span and configuration in order to study the influence on the ballistic limit. The effect of configuration was studied with 12 mm thick monolithic and double layered in contact target (2 × 6 mm) of 500 mm span diameter whereas the influence of target span was investigated by varying the diameter of 12 mm thick monolithic target as 100, 200, 300, 400 and 500 mm. The monolithic targets were found to offer higher ballistic limit than that of the layered in-contact target. The ballistic limit was also found to be affected by the variation in span diameter; its value was found to be 199.5, 213.9, 220.7, 226.08 and 230 m/s for 100, 200, 300, 400 and 500 mm span diameter respectively.
Experimental Study on a Graded Stainless Steel Sheet under Quasi-Static and Dynamic Loading
Authors: Shi Fei Fei , Hou Bing , Li Yu Long , Lu Jian , Zhao Han
Published: March 2013

Shearing tests and penetration tests were combined to determine the mechanical behavior of a stainless steel metal treated by surface mechanical attrition (SMA). SMAT is a usual treatment to strengthen the hardness of treated surface by severe mechanical strain, which generates also a gradient through the direction of thickness. This paper aimed at investigating the behavior of sheet metals treated by means of SMAT under impact loading. Double shearing tests at high strain rate were performed using Hopkinson bar. The experimental results demonstrated notable strain rate sensitivity and a good ductility without sacrificing the strength. An impact perforation test is also performed using inversed perforation test in order to study its sensibility of failure to the loading rate.
Probabilistic Strength-Reduction Stability Analysis of Slopes Accounting for 2-D Spatial Variation
Authors: Ji Jian , Liao Hong Jian , Low Bak Kong
Published: March 2013

Using the elasto-plastic constitutive model and strength reduction technique, the stability of slopes is analyzed by a finite difference numerical package FLAC version 7.0. Shear strain increment is used to identify the failure zone. Unlike the conventional investigation taking the soil strengths as constant parameters, this study deals with random variables of soil strengths by using first order reliability method (FORM). In particular, two-dimensional (2-D) spatial variation unique to soil strengths is investigated in the reliability analysis.
Effect of Strain Rate on Constitutive Behavior of AA-5052 H34
Authors: Sharma Prince , Chandel Pradeep , Mangla Vikas , Mahajan Puneet , Singh Manjit
Published: March 2013

This paper presents the experimental results to analyze the strain rate sensitivity of aluminium alloy AA-5052 H34. The experiments were carried out under uniaxial tension as well as compression. Tensile tests were carried out with UTM (Zwick Z-250) in the strain rate range of 10-4 to 10-1 s-1 using standard ASTM specimen with gauge length 50mm. Compression tests were carried out in the strain rate range of 10-4 to 103 s-1 using UTM and Split Hopkinson Pressure Bar. Cylindrical specimens of 10mm diameter and 10mm thickness were used for compression experiments. The material showed negative strain rate sensitivity in strain rate from 10-4 to 1 s-1 but showed positive strain rate sensitivity when strain rate increased to 103 s-1. The material was found to be susceptible to Portevin–Le Chatelier effect.
A Study into the Behavior of an Aluminum Foam under Compression
Authors: Mahesh C. , Deb Anindya , Kailas S.V. , Shankar C. Uma , Kutty T.R.G. , Mahule K.N.
Published: March 2013

The characterization of a closed-cell aluminum foam with the trade name Alporas is carried out here under compression loading for a nominal cross-head speed of 1 mm/min. Foam samples in the form of cubes are tested in a UTM and the average stress-strain behavior is obtained which clearly displays a plateau strength of approximately 2 MPa. It is noted that the specific energy absorption capacity of the foam can be high despite its low strength which makes it attractive as a material for certain energy-absorbing countermeasures. The mechanical behavior of the present Alporas foam is simulated using cellular (i.e. so-called microstructure-based) and solid element-based finite element models. The efficacy of the cellular approach is shown, perhaps for the first time in published literature, in terms of prediction of both stress-strain response and inclined fold formation during axial crush under compression loading. Keeping in mind future applications under impact loads, limited results are presented when foam samples are subjected to low velocity impact in a drop-weight test set-up.
Numerical Simulation of Large Deformation Problems by Element Free Galerkin Method
Authors: Kumar Rajesh , Singh Indra Vir , Mishra B.K. , Singh Akhilendra
Published: March 2013

In large deformation problems, the contribution of nonlinear terms is quite significant. Hence, components/structures involving large deformation must be analysed using non-linear theories. In this paper, element free Galerkin method (EFGM) has been applied to solve large deformation problems using updated Lagrangian approach. Geometrically nonlinear problems have been simulated assuming linear elastic material behaviour. The results obtained by EFGM have been compared with those obtained by FEM and analytical solutions. An elasto-plastic edge crack problem has been solved using nonlinear material behaviour and large deformation kinematics.
Ferroelectric Property and Microstructures of La-Doped Bi4Ti3O12 Thin Films
Authors: Mei X.A. , Liu Rui Fang , Huang C.Q. , Liu J.
Published: March 2013

La-doped bismuth titanate (Bi4-xLaxTi3O12: BLT) and pure Bi4Ti3O12 (BIT) thin films with random orientation were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique. These samples had polycrystalline Bi-layered perovskite structure without preferred orientation, and consisted of well developed rod-like grains with random orientation. For the samples with x=0.25 and 1.0 the current-voltage characteristics exhibited negative differential resistance behaviors and their P-V hysteresis loops were characterized by large leakage current, whereas for the samples with x=0.5 and 0.75 the current-voltage characteristics showed simple ohmic behaviors and their P-V hysteresis loops were the saturated and undistorted hysteresis loops. The remanent polarization ( Pr ) and coercive field (Ec) of the BLT ceramic with x=0.75 were above 20μC/cm2 and 85KV/cm , respectively.
Improvement of n/i Interface Layer Properties in Microcrystalline Silicon Solar Cell
Authors: Zeng Xiang Bo , Li Jin Yan , Xie Xiao Bing , Yang Ping , Li Hao , Xiao Hai Bo , Zhang Xiao Dong , Wang Qi Ming
Published: March 2013

Properties of n-i interface are critical for hydrogenated microcrystalline silicon (μc-Si:H )substrate-type (n–i–p) solar cell as it affects carrier collection, which is visible in the red response . Here, we report a remarkable improvement in visible-infrared responses upon hydrogen plasma treatment （HPT）of n/i interface. We demonstrate that hydrogen plasma treatment in the initial stage of a μc-Si:H i layer growth affects the red response of μc-Si:H solar cell. At the optimal deposition condition, 18% higher short-circuit current density was obtained than its count part without using HPT
Preparation at Low-Temperature and Characterization of TiO2 Film Used for Solar Cells
Authors: Wang Xiao Qiang , Li Yue Liu , Wang Jian Min , Guo Jing , Li Ming Ya
Published: March 2013

In this work, nanocrystalline TiO2 powder was prepared by the sol-gel method via tetrabutyl titanate as raw material, non-ion surfactant TO8 as a template. Then the nanocrystalline TiO2 thin film electrodes which were coated on FTO glass substrates via the slurry consiting of TiO2 powder prepared by us and the trabutyl titanate precursor were successfully prepared by using a simple and convenient hydrothermal method at low temperature. The structure and morphology of powders and films were characterized by X-ray diffraction, scanning electric microscopy. The influence factors on the samples were discussed. The photoelectric properties of cells assembled by the films were measured. The results show that, at 25°C and under 1000W/m2 light intensity，open voltage is 708mV, Jsc is 14.648mA/cm2, fill factor is 53.788, the conversion efficiency is 5.5988%.
Low Temperature Preparation and Microstructure of TiO2 Nanostructured Thin Films Coated Short Glass Fibers by Biomimetic Synthesis Technology
Authors: Wang Ming Qiu , Yan Jun , Du Shi Guo , Guo Yi , Li Hong Guang , Cui Hai Ping , Qin Hao
Published: March 2013

By using organic amine as the soft template, TiO2 nanostructured thin films have been deposited on the surface of short glass fibers (SGFs) by biomimetic synthesis technology at low temperature (85°C). The properties of composite particles, including surface morphology, the phase composition of the coating layer and microstructure were characterized by SEM, XRD, XPS and Raman. The results show that the functional layers containing NH2 and OH groups can be formed through a kind of organic amine, which can induce the bio-mineralization of nano-TiO2 on the SGFs surfaces. The XRD shows that TiO2 thin films uniformly coated on SGFs surfaces were mainly anatase. The surface roughness of SGFs was remarkably increased after coating. Compared with uncoated SGFs as filler, the abrasive loss of composite coatings decreased to 47 percent of that coatings filled with uncoated SGFs, when the composite fiber powders were filled in wear-resistant coatings based on the silicone modified epoxy resins. Therefore, anti-wear property of coatings was notably enhanced.
Structure Characterization and Hydrophilic Property of S+Ce Co-Doped TiO2 Nanocomposite Film
Authors: Xu Di Fa , Wang Hai Bo , Zhang Xiang Chao , Zhang Shi Ying
Published: March 2013

The S+Ce co-doped TiO2 nanocomposite films deposited on glass substrate had been synthesized by the sol–gel dip-coating method. The as-synthesized samples were characterized using X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and ultraviolet-visible (UV-vis) absorption spectra analysis technologies. The surface morphology and surface chemical composition of the S+Ce co-doped TiO2 nanocomposite film had been primarily investigated. The results shows that the properties of doped TiO2 thin films with different ions have close relations with the intrinsical properties of S and Ce doped ions, the absorption edge shifted towards visible light region and the water contact angle of the surface of the nanocomposite films with the water droplet was only 6°, indicating that the S+Ce co-doped TiO2 nanocomposite film showed promising applications in the self-cleaning and other potential fields.
Preparation and Performance Characterization of Nanometer-Sized Tourmaline (Schorl) Films
Authors: Li Yan , Huang Zhao Hui , Liu Yan Gai , Fang Ming Hao
Published: March 2013

Tourmaline has characteristics of repeatedly producing electric dipole polarity transformation. Using FTO glass substrate coated with conductive films as raw materials, the research aims to prepare functional glass materials, which have spontaneous polarization effect, absorption of wideband electromagnetic radiation and high visible light transmittance. This paper applied Magnetron Sputtering deposition technique, studying on tourmaline as target, sputtering on conductive FTO glass, using multiple means to measure and analyze the surface morphology, component, structure, electrical and magnetic properties. And the functions of tourmaline as composite electromagnetic shielding films are also discussed in the paper.
Effect of Pre-Recovery on Recrystallization Texture in Nickel Substrates for Coated Conductors
Authors: Chen Xing Pin , Chen Xue , Zhang Jing Peng
Published: March 2013

Electron backscattered diffraction (EBSD) technology was applied to study the effect of pre-recovery on the recrystallization texture in nickel substrates for coated conductors. Pure nickel (99.999%) was cold rolled by a 95% total reduction, and then samples were annealed at 200 °C for 1 hour and quenched for fully recovery, and finally annealed at 600 °C for 1 hour and quenched in water. The results show that pre-recovery had a strong influence on the formation of cube recrystallization texture. Compared with samples without pre-recovery treatment at 200 °C, samples through pre-recovery treatment can achieve stronger cube texture after recrystallization annealing, and develop more low-angle grain boundaries but less sigma 3 (Σ3) grain boundaries.
Copper Nanowires Preparation and Field Electron Emission Properties
Authors: Wang Li Jun , Yang Can , Wang Zi , Liu Xiao Fei , Wang Xiao Ping
Published: March 2013

Copper (Cu) nanowires films are deposited on the molybdenum film-coated Al2O3 ceramic substrates by using the electron beam vapor deposition technique. The films were characterized by optical microscopy, scanning electron microscope , x-ray diffraction spectrum and energy dispersive spectrum. The surface morphology show that the Cu nanowires have excellent length-to-diameter ratio of 300, and each Cu nanowires diameter is uniform. The field electron emission measurements of Cu nanowires films were also carried out showing the turn on field as low as 2.5 V/μm and the average current density of 0.10 mA/cm2 at electric field of 10.8 V/μm were obtained from a broad uniform emission screen over 3.0 cm2.
Influence of Sputtering Power on the Structure and Mechanical Properties of Zr-Nb-N Nanocomposite Coatings Prepared by Multi-Target Magnetron Co-Sputtering
Authors: Zhang S. , Li D.J. , Dong L. , Gu H.Q. , Wan R.X.
Published: March 2013

Ternary Zr-Nb-N nanocomposite coatings were synthesized on Si(100) substrates by Multi-target Magnetron Co-sputtering. The structure and chemical composition and binding energy of coatings were characterized by X-ray diffractometry (XRD) and Energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The results of measurements of Nano Indenter indicated that the maximum hardness was up to 36 GPa and elastic modulus was close to 425 GPa at the 30 W of Zr power and 120 W of NbN power. The hardest coating also showed the modest residual stress. These Zr-Nb-N coatings appeared to be a promising composite coating system suitable for engineering applications.
A C/SiC Graded Coating on C/C Composites by LPCVD in the Methyltrichlorosilane/Hydrogen System
Authors: He Zi Bo , Li He Jun , Shi Xiao Hong
Published: March 2013

In order to improve the anti-oxidation of C/C composites, a C/SiC functionally graded coating for C/C composites was prepared by low pressure chemical vapor deposition (LPCVD) using methyltrichlorosilane (MTS, CH3SiCl3) and H2 as precursors. The relative amount of C and SiC in coatings was varied by controlling the input ratio of H2 to MTS. The phase composition and morphology were examined by scanning electron microscope (SEM) and X-ray diffraction (XRD), and the content distribution of C and SiC phases were investigated by energy dispersive spectroscopy (EDS). The isothermal oxidation test was evaluated at 900 °C and 1500 °C respectively. The results showed that the as-obtained coatings were possessed of a dense and uniform structure, and the SiC content in coatings increased with an increment of the molar ratio of H2 to MTS. The C/SiC coating had a good oxidation resistance.
High Temperature In Situ Antioxidation Coating Fabricated by AAC Method
Authors: Wang Zhen Ting , Liang Gang , Zhao Guo Gang
Published: March 2013

In the surface of graphite electrode, the in-situ synthesized high temperature antioxidation composite coating is prepared, depending on argon arc cladding and the raw materials of Si and B4C powder. The coating consists of SiC and B13C2ceramic particles. The results show that: the reaction generates B2O3and SiO2with high temperature play a role in healing crack and preventing oxygen diffusion; a kind of continuous interface is present between the cladding layer and the graphite substrate, no obvious flaws; burning at 1573 K and 10 h, oxidation weightlessness rate is 0.912%.
Investigation of Boron Nitride Prepared by Low Pressure Chemical Vapor Deposition at 650~1200 °C
Authors: Ye Fang , Zhang Li Tong , Liu Yong Sheng , Su Meng , Cheng Lai Fei , Yin Xiao Wei
Published: March 2013

Boron nitride (BN) coatings were deposited on carbon substrates by low pressure chemical vapor deposition (LPCVD) in a large temperature range of 650~1200 °C, employing BCl3-NH3-H2 reaction system. The effects of depositing temperature on the yield, control step of deposition progress (deposition mechanism), microstructure, and crystallization degree of BN coating were investigated. Results show that BN deposition rate first increases and then decreases as the rising temperature and the maximum deposition rate occurs at 900~1000 °C. By the determination of the Arrenius relationship, there are three temperature regions with different active energies and controlled by different deposition mechanisms, i.e. chemical reaction, mass transport and depletion of reactants. Through the surface morphology observation by scanning electron microscopy (SEM), chemical composition analyses by energy dispersion spectroscopy (EDS) and crystallization degree and grain size comparison by Raman spectroscopy, it can be drawn that interphase-used BN is suitable to be deposited at 1000 °C.
Hardness and Wear Resistance of Ti-B-C-N Nanocomposite Coatings Synthesized by Multi-Target Magnetron Co-Sputtering
Authors: Gao C.K. , Liu Meng Yin , Li D.J. , Dong Lei , Gu Han Qing , Wan Rong Xin
Published: March 2013

Ti-B-C-N nanocomposite coatings were synthesized on Si(100) and stainless steel substrate by Multi-target Magnetron Co-sputtering. X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS) were employed to measure the structure and chemical states of the coatings. The measurements of nanoindenter and multi-functional tester indicated that the maximum hardness and elastic modulus were 42.8 GPa and 424 GPa when the work pressure was 0.5 Pa, the powers of Ti target and B4C were 60 and 150 W, the flows of N2 and Ar were 4 and 36 sccm, and the substrate bias was -100 V.
Influence of Power Supply Frequency on Microstructure and Properties of Micro-Arc Oxidation Coating on Aluminium Alloy
Authors: Xin Shi Gang , Le Jun , Song Li Xin
Published: March 2013

This paper studies the influence of current frequency on the micro-arc oxidation (MAO) process, microstructrue and the properties of the formed alumina coatings. The amount of discharge sparks increases and the spark moves more quickly with increasing the frequency of current pulse. SEM results show that the size of the discharge products decreases. The anodic cell voltage decreases with increasing the frequency of power supply, however, the cathodic cell voltage increases. The thickness and roughness of the coating produced using frequency of power supply 50 Hz are high. Increasing the frequency, the thickness of the coating decreases, but coating surface becomes even, and the coating possesses better corrosion protective property
Simulation and Analysis of Electromagnetic Wave Manipulation by Material with Permittivity and Permeability Very near Zero
Authors: Zhao Lin , Zhang Zhi Gang , Ding Lei , Nie Fneg
Published: March 2013

Electromagnetic properties of the material with effective permittivity and permeability very near zero (double-near-zero, DNZ) have been simulated based on the finite element method and analyzed all-around. The results of simulation show that DNZ can be used to reshape the phase front of a wave perfectly. It can be used as an angular filter as well. Furthermore, The propagation direction and the shape of phase front of EM wave can be controlled by the device which is constructed by DNZ.
The Fabrication and Photoluminescence Property of ZnO Nanosheets
Authors: Shi Ming Ji , Guo Xin Feng , Chen Lan Li , Li Shuang , Ding Shu Juan
Published: March 2013

Sheet-shaped zinc oxide nano-particles were prepared by hydrothermal method. The zinc oxide nanosheets were characterized by X-ray diffraction (XRD)，scanning electron microscopy(SEM) and photoluminescence spectrum (PL) at room temperature. The strongest diffraction apex of the nanosheet-shaped zinc oxide is assigned to crystal planes and exhibits obvious preferred orientation which is different from that of the general zinc oxide. The results show that ZnO nanosheets with about 1000nm×600nm×60 nm are obtained. The growth mechanism of the ZnO nanosheets was discussed.
Preparation and Optical Properties of Azo Polymer Containing Benzothiazole Group
Authors: Wu Guang Yu , Wang Hai Bo , Qiu Feng Xian
Published: March 2013

A novel chromophore molecule (HEPNBT) was synthesized by diazo-coupling reaction. The polyurethane (HEPU) was obtained from chromophore molecule HEPNBT, NJ-220 and isophorone diisocyanate (IPDI). The structures of HEPNBT and HEPU were characterized using the Fourier transform infrared and UV-visible spectroscopy. The refractive index (n) of HEPU was determined at different temperature and wavelength (532nm, 650nm and 850nm) using attenuated total reflection (ATR) technique, and the thermo-optic coefficient (dn/dT) was -4.149×10-4 °C-1(532nm), -7.954×10-4°C-1 (650nm) and -6.71Superscript text4×10-4°C-1 (850nm), resSuperscript textpectively. Using the CCD digital imaging devices, transmission loss of HEPU was measured and the value was 0.238 dB/cm. The results show that the obtained HEPU has a certain significance to the development of new types of digital thermo-optic switch material.
Optimization of Maximum VO2 Content in Polymorphous Oxides of Vanadium
Authors: Svitasheva S.N.
Published: March 2013

Optical properties of thin films of vanadium thermally oxidized at air were studied by ellipsometric method using wavelength of He-Ne laser. Multipart composition of these films was revealed and method of optimization of technological conditions based on dynamic of changing optical constants near 68°C was developed.
Fabrication of Electroosmotic Flow Pump on Polymethylemethacrylate Substrate Using Hot Embossing
Authors: Saito Hirofumi , Komatsuzaki Hiroki , Ikoma Ryuta , Komori Takayuki , Kuroda Keigo , Kimura Yohta , Fukushi Yudai , Maenosono Hirotaka , Koide Syohei , Satano Masahiro , Nishioka Yasushiro
Published: March 2013

Improved fabrication processes of a micro electroosmotic flow pump using hot embossing are described. The microchannels in the micropump were fabricated by hot embossing on a polymethylmethacrylate (PMMA) substrate. A silicon micromachined mold was pressed into the PMMA substrate at a temperature of 145 °C to form microchannel patterns on the substrate. The depth and width of the microchannels were 50 μm and 100 μm, respectively. Aluminum electrodes were deposited using thermal vacuum deposition. A UV ozone treatment was performed to improve adhesion between the PMMA substrate and a PMMA capping layer. This UV ozone treatment enhanced adhesion and resulted in the reduction of the adhesion temperature as low as 70 °C, and nearly no deformation of the microchannels was observed. As a result, the electroosmotic flow pump exhibited the flow rate of 0.5 μl/min when a voltage of 50 V was given between the electrodes separated 8 mm each other.
Influence of Substrate on μc-Si: H Thin Films
Authors: Wang Sheng Zhao , Yin Ying Peng , Nan Chun Juan , Shi Ming Ji
Published: March 2013

By PECVD deposition technology, we mainly investigated the influence of substrate on intrinsic amorphous/microcrystalline silicon thin film prepared at 300°C. We study the crystallization ratio, grain size of the silicon thin film specially. The results reveal that the crystallization ratio and grain size of the silicon thin film changed along with different substrates. The silicon thin film crystallization ratio and grain size changed sharply when using glass and stainless steel substrate. On this work we think ideal μc-Si:H can be obtained by using glass as substrate and in the suitable experimental conditions.
Preparation and Photoluminescent Properties of Polystyrene Encapsulated SrAl2O4:Eu2+,Dy3+ Nanocrystals
Authors: Zhai Bao Gai , Huang Yuan Ming
Published: March 2013

Polystyrene encapsulated phosphors SrAl2O4:Eu2+,Dy3+ were prepared by dispersing the phosphors into the matrix of polystyrene. The phase, morphology and optical properties of the polystyrene encapsulated phosphors were characterized with X-ray diffractometry, scanning electron microscopy and photoluminescence (PL) spectroscopy, respectively. It has been observed that both the PL spectrum and the luminescent color of the polystyrene encapsulated phosphors can be dramatically modified although the phosphorescence of the polystyrene encapsulated phosphors is not affected. Tunable photoluminescent colors from green to deep-blue are expected for the polystyrene encapsulated phosphors by the control of the weight percentage of the phosphors in the composites.
Morphology and Photoluminescence of Zn/ZnO Core-Shell Structures by Water-Boiling Method
Authors: Zhai Bao Gai , Ma Qing Lan , Xiong Rui , Huang Yuan Ming
Published: March 2013

Zn/ZnO core-shell structured composites were firstly synthesized by water-boiling method using induction cooker and electric cooker. The synthesized Zn/ZnO core-shell structures were characterized with X-ray diffraction (XRD), scanning electronic microscopy (SEM) and photoluminescence (PL) spectrophotometer, respectively. The XRD pattern confirms that the shells of the Zn/ZnO core-shell composites are composed of wurtzite ZnO crystals. Based on SEM analysis, the Zn/ZnO core-shell structures formed by intermittent boiling under induction cooker show a tendency for spherical morphology with stacked and bending ZnO shells while the ones formed by continuous boiling under electric cooker exhibit a spherical morphology with the irregular ZnO nanorods on the surface of Zn spheres, and the continuous boiling under electric cooker can promote the peeling and regeneration of ZnO shells on the surface of Zn cores. The PL spectra of the Zn/ZnO core-shell structures have been recorded at room temperature and observed two peaks around 379 nm and 538 nm. However, the defect emission is much stronger than the UV emission in the Zn/ZnO core-shell structures synthesized under electric cooker.
Channel Spoof Surface Plasmon Polaritons and its Experimental Verification
Authors: Wu Jin Jei , Lin Hung Erh , Kao Yao Huang , Yang Tzong Jer , Wu Chien Jang , Jiang Tao , Shen Lin Fang
Published: March 2013

Subwavelength guiding of channel plasmon polaritons (CPPs) is realized by a properly structured metallic groove at frequencies far below the surface plasma frequency of metal. Compared with CPPs at visible frequencies, more versatile physical mechanisms can be introduced in these CPPs by surface patterning, so that they can exhibit superior features as visible CPPs, while eliminating the potential drawbacks of the latter. Microwave experimental measurement in the transmittance verifies the high efficiency of wave guiding in such spoof CPPs, agreeing with the theoretical prediction.
Raman Scattering from ZnTe Nanocrystals Depending on Different Excitation Wavelengths
Authors: Dong Guo Bo , Wang Bi Ben , Wang Mei , Wang Jing , Li Hua
Published: March 2013

ZnTe nanocrystals were synthesized in NaOH solution by hydrothermal method and they were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and micro-Raman spectroscopy. The results indicate that the ZnTe nanocrystals were crystallized in cubic zincblende structure and their morphologies and sizes are polyhedron and diversified, respectively. The Raman results show that different scattering occurred from the ZnTe nanocrystals depending different excitation wavelengths. According to theories related to band-gap and Raman scattering, the excitation wavelength-dependent Raman scattering from the ZnTe nanocrystals was analyzed.
Development of Porous Silicon Based Visible Light Photodetectors
Authors: Huang Yuan Ming , Ma Qing Lan , Zhai Bao Gai
Published: March 2013

Porous silicon based visible light photodetectors with the characteristic structures of Al/porous silicon/Si were developed by evaporating aluminum contact onto the top surface of porous silicon films to form metal-semiconductor-metal Schottky junctions. The spongy nanostructures of the porous silicon film were characterized with the scanning electron microscopy. The current-voltage characteristics, the biased voltage dependent photocurrents and the illumination intensity dependent photocurrents were measured for the Al/porous silicon/Si visible light photodetectors. It is found that the photocurrents as large as 4 mA/cm2 can be achieved for the porous silicon based visible light photodetectors under the normal illumination of one 500 W tungsten lamp
Raman and Photoluminescence Properties of ZnO Nanorods with Wurtzite Structure
Authors: Li Chun Ping , Zhang Jian , Yu Hua Min , Zhang Li Zhong
Published: March 2013

Raman, resonant Raman and photoluminescence (PL) properties of ZnO nanorods that produced by simple solution chemical process are reported in this paper. The transmission electron microscopy measurements show that the obtained ZnO nanorods have well-proportioned distribution with diameters about 30 nm, and the maximal lengths up to more than 2.2 μm. The micro-Raman and resonant Raman spectrum of nanorods show the obvious differences from that of the commercial bulk phase ZnO samples. The PL with intense UV emission indicates the good quality of the obtained ZnO nanorods.
Microstructural and Luminescent Properties of ZnO Prepared by Chemical Solution Growth Method
Authors: Shi Ming Ji , Zhang Li Na , Chen Lan Li , Wang Sheng Zhao , Li Shuang
Published: March 2013

In this thesis, ZnO nanostructures with different morphologies were synthesized on silicon substrates by chemical solution growth method from Zinc acetate and methenamine aqueous solution at 70°C for 4 hours. Its morphologies by SEM and its crystal structures by XRD were studied．Its photoluminescence spectrum was also measured．And possible mechanisms of the growth and the photoluminescence of ZnO were proposed to explain the experimental result．
Thermo-Sensitive Nanogated System Based on Polymer-Modified Mesoporous Silica Hybrid Nanoparticles
Authors: Tang Xin De , Yu Fa Qi , Chen Ye , Pei Mei Shan
Published: March 2013

Mesoporous silica nanoparticles (MSNs) have been employed as a versatile solid support for constructing a variety of hybrid materials for controlled drug delivery. Controlled release systems that integrate external stimuli with nanocarriers have attracted much attention for sensors and drug delivery applications. Mesoporous silica nanoparticles grafted with thermo-sensitive polymers on the surface were fabricated via “grafting to” approach through chemical coupling reaction. The encapsulation and release of drug based on the thermo-sensitive nanogated system were investigated. The thermo-sensitive nanogated system can be expected as one of the promising candidates for drug delivery and controlled release.
Performance Optimization of AIN Films Using Self-Prepared AIN Target
Authors: Wang Xiao Yan , Gu Feng , Xu Meng Jie , Shi Tian Shi , Shen Yue
Published: March 2013

Aluminum nitride (AlN) films were prepared by radio frequency (RF) sputtering technique with self-prepared AlN ceramic target. The influence of substrate type and working gas of different N2 concentration to performance of AlN films were discussed. Microstructures of the films have been studied by X-ray diffraction (XRD) and scanning electron microscope (SEM). And, the optical properties have been revealed by diffuse reflection spectrum (DRS). The optimized process to prepare AlN film of single orientation (100) was as follows: deposited on Si (100) substrate and 25% N2 concentration, 250W-300W sputtering power and 90min sputtering time, respectively.
29Si NMR Characterization of Silica Tetrahedron in the Silica Fume Simulate Hydration
Authors: Wang Xiao Jun , Wang Xiao Yao , Zhu Hong Fei , Qian Chen
Published: March 2013

As the major structure of silica fume, the change of silica tetrahedron in the pozzolanic reaction during the hydration has not been revealed clearly in previous studies. In this study, 29Si solid-state MAS NMR was used to characterize the silica tetrahedron change of the silica fume in saturated alkali solution with 0.9, 1.2, 1.5 and 1.8 four different calcium/silica ratios. The amorphous Q4 silica tetrahedron structure in silica fume changed into Q1 silica tetrahedron at 1 day. Q2 silica tetrahedron formed from Q1 silica tetrahedron within 3 days. Q1 and Q2 silica tetrahedron reached a balance until silica fume completed pozzolanic reaction and the Q4 silica tetrahedron exhausted. The coexistence of Q1 and Q2 silica tetrahedron benefited the physical properties increase of cementitious system. 29Si solid-state MAS NMR results proved that the chain length of silica tetrahedron in C-S-H shortened in the silica fume hydration while the C/S ratio increased.
Carbonation Profile of Cement Paste and Concrete Established with Micro-Hardness Analysis
Authors: Chen Wei , Chen Xiao Xing , Zhang Shi Zhe
Published: March 2013

A new method for establishing the carbonation profile of cement paste and concrete with the micro-hardness analysis is proposed in this study. This method is able to probe the changes in the microstrucure during the carbonation process. The results are validated with the conventional phenolphthalein indicator method.
The Effect of Electrochemical Chloride Extraction Combining Ultrasonic on Steel-Reinforced Mortars
Authors: Xing Xiao Ming , Yao Wu
Published: March 2013

A creative methodology of ultrasonic-electrochemical chloride extraction (UT) is proposed which is an improvement of the traditional electrochemical chloride extraction (ECE) through the assistant of ultrasonic wave and according experimental investigation on the viability of this method is carried out. The results indicated that the Cl- extraction efficiency of UT was approximately 19% higher than that of ECE, and the corrosion current density of UT group obtained through Linear Sweep Voltammetry was also the lowest which further demonstrates that ultrasonic wave had positive and obvious effect on halting the corrosion of Cl- on steels.
Analysis of Bond and Anchorage Performances of Helical and Twisted Reinforcement Material
Authors: Zhang Jun Lin , Wang Chun Li
Published: March 2013

The performance of helical-effect of the helical and twisted material is elaborated in this paper. Through analyzing the parameter of the helical and twisted material, a mechanism model based on the bond of anchorage is built. Furthermore the fundamental derivation formula is done and the sensitivity is analyzed. Based on systematic study of bond anchorage performance of helical and twisted reinforcement material, the mechanical of the helical-effect was theoretically analyzed and quantitatively studied. The relationship between pullout and bond slip was studied by mechanical analysis and mathematical modeling stage by stage, the formula was established and derived. As a result, theoretical understanding of the helical-effect was deepened, providing the theoretical basis for optimization of material properties, geometry parameters and developing new materials.
Study on Pore Structure Characterization of Concrete at Different Ages by Thermoporometry
Authors: Jiang Zheng Wu , Deng Zi Long , Zhang Nan
Published: March 2013

In this paper, pore structures and their changes of ordinary-strength concrete and high-strength concrete at different curing ages of 3, 28, 90 days were studied using thermoporometry, and the results were compared with those from MIP and NAD. The relationship between micro pores and porosity of concrete and its macroscopic properties was also studied. The results indicate that, compared to MIP, thermoporometry can characterize the features of pores with the diameter smaller than 100 nm in concrete accurately. The differences of macroscopic mechanical properties of concretes can be explained using the changes of their pore size distribution. After curing age of 28 days, the amount of pores with the diameter higher than 20 nm in high strength concrete changes little, but it decreases gradually in ordinary strength concrete. And pores with diameter smaller than 20 nm in concrete have little influence on the macroscopic mechanical property of concrete.
Determining the Contact Angle of Hardened Cement Paste Using Thin Layer Wicking Method
Authors: Tian Qian , Zhang Hang , Wang Yu Jiang , Guo Fei , Yao Ting , Liu Ji Ping
Published: March 2013

Contact angle is a very important parameter to investigate the function mechanism of chemical admixtures as well as the capillary stress resulted from self-desiccation or drying. However, in most of the studies, it is only assumed to be 0 degrees. This paper studied the contact angle of hardened cement paste using thin wicking method. A serious of study was conducted on the influence of layer preparation, pre-contacting method, cement paste powder size, and suspension concentration on the measuring results. An optimized thin layer wicking method was proposed for determining the contact angle of hardened cement paste, which improves effectively the linear correlation of the penetration distance - time curve and satisfies the prerequisite of Washburn function.
Preparation of AgBr Nanowire Arrays in Porous Anodic Aluminium Oxide Template by Paired Cell Deposition
Authors: Cui Miao Miao , Yang Xiu Chun , Hou Jun Wei
Published: March 2013

Firstly, porous anodic aluminum oxide template was prepared by a two-step anodization process, then AgBr nanowire arrays were successfully synthesized by paired cell deposition. X-ray diffraction (XRD) indicates that the as-synthesized samples are composed of face-centered AgBr. Field-emission scanning electron microscopy (FESEM) shows that the average diameter of the nanowire arrays is about 70nm.
A Testing Device for Humidity-Control Performance of Pervious Concrete
Authors: Wu Jun Long , Wu Xiong , Lv Xiao Feng
Published: March 2013

Abstract. With the more application of pervious concrete in China, its ecological benefits was paid more attention, especially improve "heat island effect"of the urban; In this paper, according to the mechanism of pervious concrete how to improve atmospheric humidity, the testing device for humidity-control performance of pervious concrete for laboratory testing was designed, humidity sensor is used in combination with automatic acquisition program, the equipment can test the humidity-control of pervious concrete under different conditions.
Investigation of a Software for Finite Element Model Updating of Bridges Based on Interface Technology between VC++ and MATLAB
Authors: Liu Yang , Lv Zhan , Zhang Hong
Published: March 2013

To develop an effective software for finite element (FE) model updating of bridges, the interface technology between VC++ and MATLAB was investigated firstly, and then a software for updating FE model of bridges, named Doctor for Bridges (version 1.0) was developed. Finally, a model ofconcrete-filled steel tube arch bridge was applied to verify the performance and effectiveness of the proposed software.