bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimized Conjugative Bridge and its Length in Novel Chromophores for Electro-Optical Applications
Authors: Zhang Xian Min , Bao Han , Qin Gao Wu , Yokoyama Shiyoshi
Published: March 2016

Two group chromophores with strong methoxy electron donor and CF3 electron acceptor were synthesized and reported. To investigate the effects of conjugative bond and its length between electron donor and acceptor on optical properties, thiophene ring was incorporated into the conjugated units of group B compared to group A. The results showed that the incorporation of thiophene rings could significantly enhance molecular first hyperpolarizability and permit a high thermal stability. It has been found that molecular first hyperpolarizability increased continually by the increase of bond length of group A. However, further increase of conjugated bond length between electron donor and acceptor in group B reduced the molecular hyperpolarizability. This study indicates that both the nature of the conjugative bridge and its bond length between electron donor and acceptor have inner correlation to optimize the molecular hyperpolarizability for electro-optical applications.
Thermoelectric Properties of β-Zn4Sb3 Thin Films Deposited on Polyimide Flexible Substrate
Authors: Li Feng , Fan Ping , Luo Jing Ting , Zheng Zhuang Hao , Liang Guang Xing , Zhong Ying
Published: March 2016

Due to the high-performance in the medium temperature application, β-Zn4Sb3 thermoelectric material has been received much attention. It is found that low dimensional thin film can improve the thermoelectric properties of materials by quantum local area effect and interface effect in recent years. In this paper, the β-Zn4Sb3 thin film was prepared on polyimide flexible substrate by DC magnetron co-sputtering method. The results showed that the thin film exhibited predominately ZnSb phases when the thin film was prepared by DC magnetron sputtering using Zn4Sb3 alloy target. It is suggested that the element Zn has high saturated vapor pressure and the thin film is lack of Zn due to the evaporation during the heat treatment process. We further adopted co-deposition Zn and Zn4Sb3 by DC magnetron co-sputtering to supplement the content of Zn. The sputtering power of Zn4Sb3 is fixed and Zn is set to 21W, 27W and 34W, respectively. The results indicated that the thin films transformed from ZnSb phase into β-Zn4Sb3 phase after Zn added. EDS analysis demonstrated that the atomic ratio of Zn:Sb was approach 4:3, and a slightly surplus of Zn. The thermoelectric properties of thin films with β-Zn4Sb3 phase were improved obviously.
Effect of Plasmid DNA Dimension Evolution on the Size of Ag Nanoparticles during Photoirradiation
Authors: Zhang Jin Dan , Yu Mei , Liu Jian Hua , Li Song Mei , Meng Yan Bing
Published: March 2016

Under the photoirradiation, DNA works as both template and reducing agent to drive the formation of metallic nanomaterials. In this study the plasmid DNA with different base pairs was applied as biotemplate to synthesize Ag nanoparticles (NPs) by using photoirradiation approach. The evolution of DNA dimension changed during the synthesis process, and their effect on the morphology of the synthesized Ag NPs was studied by UV-Vis spectra, FT-IR spectra, Raman spectra, AFM, and TEM. It is found that the plasmid DNA shrinked twice during the synthesis, the first time happened when the Ag (I) cations neutralized the negative charge along the DNA chain, and the second time happened when plasmid DNA reduced Ag (I) induced by the ultraviolet C (254 nm) irradiation. The size of the synthesized Ag NPs showed approximately linear relationship with the dimension of plasmid DNA scaffolds under this photo-induce condition. The compaction degree of the plasmid DNA during the Ag formation was shown by the slope of the linear relationship.
Adsorption of Acid Carmoisine B by Fly Ash/Chitosan Composite
Authors: Li Bei Gang , Han Shuang Yan , Teng Rui
Published: March 2016

With synthetic wastewater, the adsorption characteristics of acid carmoisine B (AC B) on fly ash/chitosan (FA/CTS) composite material prepared by FA loaded with CTS were investigated using a lab-scale batch experiment technique. The optimum preparation conditions for FA/CTS composite were obtained and the composite was further characterized by SEM. The adsorption rate of AC B onto FA/CTS is very fast and the adsorption can reach equilibrium in 60 minutes. Temperature may accelerate the adsorption rate. Equilibrium experimental data are well fitted to linear Langmuir model with the saturated adsorption capacity of 232.56 mg/g at 25°C and the nature of a monolayer adsorption. Dubinin-Radushkevich (D-R) isotherm model was applied to describe the nature of AC B sorption, and it has been found that AC B sorption mainly occurred chemically, but physisorption also exists at same time. The values of thermodynamic parameters, the change of free energy (ΔG◦), enthalpy (ΔH◦) and entropy (ΔS◦) of sorption calculated, show that the sorption process of AC B on FA/CTS is spontaneous and endothermic at 25~55°C. The results indicate that there is significant potential for FA/CTS as an effective adsorbent material for AC B removal from dye wastewater.
Preparation of Coated CMC-nZVI Using Rheological Phase Reaction Method and Research on Degradation of Chloroform in Water
Authors: Yu Shu Zhen , Cheng Yue , Fan Xiao Feng , Xu Li Ping
Published: March 2016

This study reported the synthesis of nanoscale zero-valent iron (nZVI) by rheological phase reaction method in the presence of sodium (CMC). The synthesized CMC coated nZVI (CMC-nZVI) was then characterized with x-ray diffraction (XRD) and transmission electron microscope (TEM) and was tested for the removal of chloroform from simulated groundwater. The investigated parameters in the uptake experiments included different adsorbents, initial concentrations of chloroform and different water flow. The results show that:(1) the prepared CMC-nZVI has good stability and dispersibility; (2) when the concentration of chloroform is 0.1 mg/L, the dosage of CMC-Fe0 is 0.01 g, the removal rate of chloroform is 91.2%;(3)The reaction follows the first-order kinetic reaction equation, and the apparent reaction rate constant increases with decreasing the concentration of chloroform.
Microwave and Tween-80 Assisted Hydrothermal Synthesized of BiVO4 and its Improved Photo Catalytic Activity under Visible Light
Authors: Qiu Tao Yu , Feng Qin Ge , Liu De Jiang , Wang Xin Ye
Published: March 2016

Monoclinic BiVO4 nanosheets were successfully synthesized by the microwave hydro-thermal method in a relatively short time with TW-80(C64H124O26-80) acted as the soft template. The effect of pH, synthesizing time on the morphology, and dosage of TW-80 were investigated in detail. The crystal form, morphology and absorption spectrum of the as prepared BiVO4 samples were characterized by means of x-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis diffuse reflectance spectroscopy (DRS) respectively. The experimental results demonstrated that the samples synthesized both under acid and neutral environment showed the higher photo-catalytic activity. Up to 98% of MB was degraded in 300 minutes. The certain amount of TW-80 added in synthesizing BiVO4 altered the morphology, resulted in the appearance of more active sites, shortened the transmittance distance of the carriers and thus enhanced photo-induced electrons separation efficiency.
The Influence of Organosilane on Physicochemical Characterization of Waste Leather Powder with Different Size
Authors: Wang Ya Juan , Li Ya , Zhang Xin , Wu Ning Kun , Shao Shuang Xi
Published: March 2016

In order to reduce the pollution of the waste material, the waste leather powder tanned with vegetable tannin was used in this work, and vinyitrimethoxy silane was chosen as coupling agent. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to investigate the thermal properties of the powder sample. Both thermal decomposition temperature and denaturation temperature of the modified sample were higher than those of the raw samples due to the interaction between leather powder and silane, which can be demonstrated by Scanning Electron Microscopy-Energy Dispersive Spectrometer (SEM-EDS) and Fourier Transform Infrared Spectroscopy (FT-IR). Additionally, the flowing property, hydrophilicity and water absorption rate of the powder samples was also examined. The results showed that the hydrophilicity and moisture absorption of the leather powder sample modified with silane was lower than the raw materials. And the flowing properties of the modified samples also decreased because of the coupling reaction of the flexible vinyitrimethoxy silane.
HRP Immobilization on Activated Carbon/Polyvinyl Formal Composite Materials for Degradation of Phenolic Wastewater
Authors: Xu Sai Nan , Chen Yong
Published: March 2016

A novel method was developed for degradation of phenolic waste water using horseradish peroxidase (HRP) immobilization on activated carbon/polyvinyl formal (AC/PVFM) composite materials in this study. The materials were black-sponge-like, soft and elastic, and had three-dimensional porous network structure. Optimum conditions of immobilized HRP carrier preparation technology was selected by orthogonal experiment. The enzymatic properties were explored and compared between immobilized and free enzyme. The optimum pH of immobilized HRP and free HRP were both 4, nevertheless, the immobilization of HRP increased the enzyme activity. The optimum temperature of immobilized HRP was 20°C which was lower than that of free HRP (25°C), therefore the immobilized HRP could resist to lower temperature. The Km of immobilized HRP and free HRP were 0.23 mmol/L and 0.40 mmol/L, respectively. The lower Km value of immobilized HRP indicated higher affinity to the substrate. These results show that HRP immobilized on AC/PVFM composite materials is promising in phenolic wastewater degradation.
A Novel Formaldehyde Gas Sensor Based on Ag-LaFeO3 Using Molecular Imprinting Technique
Authors: Zhang Yu Min , Hu Chang Yi , Zhang Jin , Liu Qing Ju , Zhu Qin , Zhu Zhong Qi
Published: March 2016

A novel gas sensor for the determination of formaldehyde was developed based on molecular imprinting technique (MIT). MIT was for the first time used to recognize small organic molecule by our group. The molecular imprinting nanoparticles (MINs) with a small dimension which possess extremely high surface-to-volume ratio were synthesized using imprinting polymerization with formaldehyde as template and Ag-LaFeO3 as substrate material. The structure of the MINs is orthogonal perovskite. And then the MINs were printed onto an alumina tube. Subsequently, a high selectivity molecular imprinting gas sensor for detection of formaldehyde was achieved. At 86°C, the response to 0.5 ppm formaldehyde based on the sensor is 16, and the response is lower than 2 for the other test gases. The response time and recovery time are 55 s and 40 s, respectively.
Preparation of Nano-MnO2 and Adsorption of Reactive Brilliant Blue
Authors: Fan Xiao Feng , Cheng Yue
Published: March 2016

MnO2 nanoparticles were prepared by one-step redox under room temperature. The sample was characterized by XRD, SEM, TEM and FT-IR. The results indicated that the MnO2 nanoparticles was amorphous δ-MnO2 with the uniform size of 10-20nm in particle diameter, which can be seen by XRD patterns. The four peaks appear at 2θ = 23.24°,36.1°,45.42°and 64.38°, respectively. FT-IR results showed the 519 cm-1 as Mn-O features manganese dioxide absorption. The effect of the pH, nanoMnO2 dosage, reaction time, reaction temperature and initial concentration were studied on the removal of reactive brilliant blue. It was found that the removal ability of reactive brilliant blue was the best under the selected conditions: pH was 3.0, dosage of nanoMnO2 was 0.05g, KN-R solution concentration was 5mg / L, reaction time was 2h, temperature was 25°C.
Challenges of Resource, Environment for Development of Materials Science and Engineering in China
Authors: Ding Xiao Hua , Chen Xiang Dong , Hao Wei Chang , Wang Tian Min
Published: March 2016

China is now confronted with the tasks of both promoting the economic growth and protecting the environment. Environmental protection has been adopted as the basic national policy to achieve sustainable development. The progress and innovations in the field of material science and engineering are expected to make great contributions since they can help to increase efficiency and reduce pollution. In this paper, the environment situation in China was reviewed to highlight some certain fields that need the efforts from material scientists. And some new technologies were also discussed as the potential methods to deal with these problems. In summary, this paper can be served as a clue for the material researchers who want to contribute to Chinese environmental protection.
Effect of CO2 on the Permeation of Hydrogen in Carbon Steel in H2S Environment
Authors: Bai Peng Peng , Liang Yu Xuan , Liu Li Wei , Zhou Cheng Shuang , Zheng Shu Qi , Chen Chang Feng
Published: March 2016

The effect of CO2 on the hydrogen permeation behaviour of carbon steel was investigated in a high temperature and high pressure hydrogen permeation device, through hydrogen permeation test, weight loss test, hydrogen content test, and SEM-EDS. The results showed that the peak value of the hydrogen permeation curves were almost the same with or without CO2, but the hydrogen permeation curve rose sharply, and then decreased gradually to a stabilized current value in H2S/CO2 environment, which was lower than in H2S environment. The corrosion rates and the amount of hydrogen of steel in H2S/CO2 environment were lower than in H2S environment. Therefore, it is considered that CO2 has an effect on the hydrogen permeation in H2S, mainly due to the change of corrosion products.
Research of Nanosilica Particles Grafted with Functional Polymer Used as Fluid Loss Additive for Cementing under Ultra-High Temperature
Authors: Xia Xiu Jian , Guo Jin Tang , Liu Shuo Qiong , Jin Jian Zhou , Yu Yong Jin , Feng Ya Kai
Published: March 2016

On account of that the domestic polymer fluid loss additive exists some severe problems, such as, inferior thermal resistance, poor salt tolerance, strong shear-and thermal thinning behavior, a novel polymer/silica nanocomposite PADMO-V@NS is used as ultra-high temperature fluid loss control additive for cementing. In the present study PADMO-V@NS was prepared through an in situ free radical copolymerization of 2-acrylamico-2-methylpropane sulfonic acid (AMPS), N,N-dimethylacryl amide (DMAM), maleic anhydride (MA), octadecyl dimethylallyl ammonium chloride (ODAAC) and triethoxyvinylsilane (VTS) modified nanosilica. The linear hydrophobic associated copolymer was regarded as the shell and the modified nanosilica as the core. The microstructure, compositions and thermal resistance of PADMO-V@NS were investigated through FTIR and TGA techniques. The results showed that the copolymer modified with nanosilica particles possessed more excellent thermal stability than that of PADMO, and the most rapid decomposing temperature of PADMO-V@NS was highly up to 396.9°C. The application performance of PADMO-V@NS in cement slurry exhibited that it had excellent fluid loss control capacity, good high temperature resistance, strong salt tolerance and mild shear-/ thermal thinning performance, and could be used in 220°C and saturated brine circumstances. Moreover, comparing to PADMO, the compressive strength of set cement containing the copolymer increased over 20 % at 80°C, atmosphere pressure and curing time of 1 day due to the reaction of residual silanol groups with Ca (OH)2. The laboratory research results indicated that the multi-functional fluid loss additive composed of hydrophobic associated polymer/silica nanocomposite had bestowed on the cement slurry systems good comprehensive properties, and may have extensive applications in deep & ultra-deep oil/gas wells cementing.
Synthesis and Shape Memory Property of a MDI Based Liquid Crystalline Polyurethane
Authors: Li Yue Ting , Lian Hui Qin , Hu Yan Ou , Zu Lei , Cui Xiu Guo , Liu Yang , Liu Yu Peng , Wu Ben Ze
Published: March 2016

Liquid crystalline polyurethanes (LCPU) were prepared from 4,4’-methylenediphenyl diisocyanate (MDI), 1,6-hexanediol (HDO), 2,2-dimethylol propionic acid (DMPA) and polytetramethylene ether glycol (PTMG). The experiments synthesized three liquid crystalline polyurethane films with different soft/hard segment ratio. Chemical and structural characterization of the polyurethanes were investigated by Fourier transform infrared, X-ray diffraction, thermogravimetric analysis, differential scanning calorimeter and polarized microscopy respectively. Swelling rate and shape memory property were tested. The results indicated that the polyurethane with 62% soft segment and large group of carboxyl displayed excellent swelling and shape memory properties, and the shape recovery rate reached 100%. It was found that the crystallinity, thermal stability decreased and the temperature flexibility, water absorption and shape recovery rate increased with the increase of polytetramethylene ether glycol.
Effects of Ionic Group on the Shape Memory Performance of Polyurethane
Authors: Hu Yan Ou , Lian Hui Qin , Zu Lei , Li Yue Ting , Liu Yang , Cui Xiu Guo , Hu Zhong Kai , Jiang Yan Hua , Wang Lei , Liu Yu Peng , Wu Ben Ze
Published: March 2016

Ionic polyurethane (IPU) was synthesized as shape memory materials. Poly (tetramethylene ether) glycol with 2000g/mol number average molecular weight were used as soft segment, 4,4-methylenebis (phenyl isocyanate), and 1,2-dihydroxy-3-propanesulfonic acid salt were used to compose the segment of SMP materials. The structure and properties of these IPU films were characterized by Fourier Transform infrared, X-ray diffraction, Thermal gravimetric analysis and Differential scanning calorimeter. The results showed that the glass transition temperature of the IPU increased with the increase of hard segment content. The physical properties in terms of swelling property, water absorption and ion-exchange capacity increased with the improving of sulfonic group content in IPU. The shape memory property of IPU exhibited that the shape fixity ratio and recovery rate improved remarkably with the increase of hard segment content.
Phenylethynyl-Terminated Polyimide Oligomers with Low Viscosity and Good Thermal Properties
Authors: Yu Ping , Wang Yan , Yu Jun Rong , Zhu Jing , Hu Zu Ming
Published: March 2016

A series of addition-type imide oligomer (degree of polymerization: n=1-9) derived from 2,3,3',4'-diphenyl ether tetracarboxylic acid dianhydride (a-ODPA), 3,4'-oxydianiline (3,4'-ODA) and 4-phenylethynylphthalic anhydride (PEPA) was synthesized by thermal imidization. The resultant oligomers were characterized for their chemical architecture, thermal property, and processability. The experimental results showed that oligomers PI-1 and PI-2 had somewhat crystalline phase. PI-4, PI-6 and PI-9 exihibited high solubility in solvents. These imide oligomers have a very low melt viscosity, and thus provide wide processing window by the rheological behaviors. Furthermore, the cured polyimides exhibited excellent thermal stability under N2 atmosphere. The temperatures of 5% weight loss in N2 atmosphere were all above 524°C.
Variation of Magnetoelectric Coefficient with Volume Fraction of Piezoelectric Phase in Pb(Mg1/3Nb2/3)O3-PbTiO3/FeCoV Laminate Composite
Authors: Du Zhao Fu , Zhang Sam , Ding Hui , Wang Lei , Zhang Hong Ping , Zhao Dong Liang
Published: March 2016

Soft magnetic material FeCoV is sensitive to magnetic field and its cost is lower than giant magnetostriction materials (Terfenol-D et al.). In the present investigation Pb (Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) with different thickness and FeCoV laminate with 0.8mm thickness were assembled into layer structure to study the effect of the PMN-PT volume fraction on the magnetoelectric coefficient of PMN-PT/FeCoV laminate composites. The ME coefficients and voltages have been characterized in the longitudinally magnetized and transversely polarized mode. The measurement was conducted under a static magnetic field superimposed with an alternating magnetic field. The influences of the static and the alternating field strength were discussed. The peak ME coefficient was obtained at 430 Oe. With the volume fraction of PMN-PT increased, the ME coefficient decreased within the experiment fraction. It can be explained by the module of M.I.Bichurin. A linear relationship was observed between the magnetoelectric voltage and the alternating field strength under a static field of 400 Oe. The ME voltage decreased when the PMN-PT volume fraction increased in the experiment fraction.
Influence of Confinement on Ceramic’s Mechanical Properties
Authors: Hang Xiao Cong , Li Yun Kai
Published: March 2016

The wide use of ceramic material in engineering is restricted by its brittleness, so the strengthening and toughening of ceramics is always a hot spot of research in material area. And in general, the modification of ceramics is achieved by changing its internal microstructure. In this paper the influence of confinement on the mechanical properties of ceramics and the specific use of this method were investigated. Firstly, the influence of confinement on ceramic’s fracture process was analyzed in theory. Then the three-point bending test was conducted using two types of ceramics, viz. Zirconia and Alumina. The experimental results showed that the fracturing load of zirconia increased from 4.3298 to 5.4639KN as the confinement was increased from 0 to 150MPa, 26.19% increase was found in the confined specimen. The same trend was observed in alumina, whose fracturing load increased from 3.0446 to 5.0259KN as the confinement was increased from 0 to 150MPa, 65.07% increase was found. After that, a series of ballistic experiments were performed. The target in this experiment was boron carbide ceramic, and it was confined by 45 steel. The results showed that with the constraint force was bigger, the ballistic efficiency factor was better and the depth of penetration was smaller. In other words, the confinement can increase the defensible performance of the target. In summary, the ceramic’s fracture toughness, defensible performance and ballistic efficiency factor can be increased by adding confinement to it.
Effect of Y2O3 on the Sintering, Mechanical and Dielectric Properties of Mullite/h-BN Composites
Authors: Jin Han , Li Yong Feng , Shi Zhong Qi , Xia Hong Yan , Qiao Guan Jun
Published: March 2016

Mullite/10 wt. %h-BN composites with 5 wt. % Y2O3 additive were fabricated by pressureless sintering at different temperatures. The densification, phase composition, microstructure, mechanical and dielectric properties of the mullite/h-BN composites were investigated. With the addition of Y2O3, the sintering temperature of the mullite/h-BN composites declined, while the density, mechanical and dielectric properties all increased. The addition of Y2O3 promoted the formation of liquid phase at high temperature, which accelerated the densification. Besides, Y2O3 particles which were located at the grain boundaries inhibited the grain growth of mullite matrix. For the mullite/h-BN composites with Y2O3 additive, the appropriate sintering temperature was about 1600°C. The relative density, flexural strength, fracture toughness and dielectric constant of the Y2O3 doped mullite/h-BN composite sintered at 1600 °C reached 82%, 135 MPa, 2.3 MPa·m1/2 and 4.9, respectively.
Effect of Heat Treatment on the Preparation of Zircon Whiskers
Authors: Zhang Tao , Jiang Wei Hui , Liu Jian Min , Feng Guo , Zhang Quan , Miao Li Feng
Published: March 2016

Zircon whiskers were synthesized via non-hydrolytic sol-gel process combined with molten salt method by using anhydrous zirconium tetrachloride as zirconium source, TEOS as silicon source, anhydrous ethanol as solvent, and sodium molybdate as molten salt. The effects of heat treatment mode and cooling rate on the synthesis of zircon whiskers have been studied by means of XRD, FE-SEM, TG and TEM. The results indicate that well-developed whiskers can be prepared through heat treating the sample at 850°C for 3 h followed by a furnace cooling process. The zircon whiskers which were fabricated by this heat treatment mode grew along the [001] direction and showed diameter of 50~100 nm and aspect ratio of 20~30.
Effects of Al2O3 Buffer Layer on the Properties of ZnO: Al Thin Films Deposited on Glass by Sputtering
Authors: Wang Xiao Jing
Published: March 2016

The ZnO:Al (AZO) films were deposited on glass substrates with Al2O3 buffer layers by RF magnetron sputtering. The obtained films had the hexagonal structure and preferred orientation of (002). Compared with AZO film without buffer layer, the grain size of the film with buffer layer was increased and the conductive property was increased greatly. the grain size of AZO films reached 27.9nm for those with buffer layers. The optical property of AZO films was decreased by the buffer layers. The resistivity of AZO films with Al2O3 buffer layer was about 6.6×10-3 Ω·cm and the average transmittance was over 80% in the range of 450~900nm.
Preparation of Highly Transparent Silica Glass by SPS Sintering of SBA-15
Authors: Shi Li Wei , Wang Lian Jun , Jiang Wan , Luo Wei
Published: March 2016

Silica glass was prepared via the spark plasma sintering (SPS) method by using SBA-15 as the starting material. Five temperatures (1000, 1010, 1020, 1030 and 1040°C) were selected as the final sintering temperature above 600°C. The transparent silica glass was prepared by SPS sintering of mesoporous silica SBA-15 at 1040°C. The impact of temperature structure collapse of SBA-15, the structure and transmittance of the glass were studied using X ray diffraction, SEM, TEM, Infrared analysis, Raman analysis and UV-VIS spectrophotometer. Results show that SBA-15 collapsed completely at 1040°C, the sintered glass had high transmittance of above 90% in visible spectra, and its hardness was 6.96 Gpa, and that the sintered transparent sample was silica glass. The work demonstrated a novel strategy to use SPS to prepare highly transparent silica glass by sintering of SBA-15.
Fabrication of SiCf/SiC Composite with In Situ Grown SiC Nanowire by Polymer and Infiltration Pyrolysis Process
Authors: Zeng Sui Juan , Yu Jin Shan , Zhou Xin Gui , Wang Hong Lei
Published: March 2016

SiC nanowires were in-situ grown in SiC fiber fabrics by chemical vapor deposition (CVD) process via pyrolysis of polycarbosilane (PCS) at 1300°C and 1400°C, respectively. Then SiCf/SiC composites were fabricated with the fabrics by polymer and infiltration pyrolysis (PIP) process. Single-filament tensile strengths of the SiC fibers heat treated at different temperature were measured. It was indicated that the mechanical property of the KD-ISiC fiber significantly degenerated above 1100°C, especially at 1400°C. Nevertheless, the prepared SiCf/SiC composite with in-situ grown SiC nanowires exhibited good mechanical performance, suggesting that the SiC nanowire is an effective reinforcement for the SiCf/SiC composite.
Preparation and Dielectric Property of C/SiO2 Composite via Self-Assembly
Authors: Zhang Zi Dong , Ji Xiu Jie , Qin Chen , Wang Hui Min , Chen Shu Hui , Xie Pei Tao , Fan Run Hua
Published: March 2016

In this paper, C/SiO2 bulk composite was prepared via SiO2 microspheres’ self-assembly process combined with heat treatment. SEM and impedance analyzer was used to investigate the microstructure and high-frequency dielectric properties of the composites. The results show that SiO2 microspheres constituted the composite matrix, whose porosity was slightly higher than the densest hexagonal stacking. Sheet carbon distributed in pores formed by SiO2 microspheres. The real and imaginary parts of the dielectric constant of the composite material increased with the content of carbon, but decreased with the frequency. The permittivity of C/SiO2 composite could be adjusted by control the concentration of PVA solution.
Preparation of Anode-Supported SOFC Electrolyte Membrane and Porous Anode Material
Authors: Li Fei , Zhang Jing De , Luan Jun Peng , Liu Ya Lei
Published: March 2016

The graphite was used as pore-forming agent to prepare porous NiO-Yttria-stabilized zirconia (YSZ) anode material. The influence of the content of pore-forming agent of the anode material, and the change of the anode material before and after the reduction of NiO were investigated. It was found that the porosity and shrinkage rate of the anode increased with the addition of the pore-forming agent, and the thermal shock resistance also improved. We chose Y(NO3)3·6H2O and ZrOCl2·8H2O as raw materials, ethylene glycol monomethyl ether as solvents to make collosol. And electrolyte membrane on the Si piece was prepared by spin-coating. The electrolyte membrane would be thinner if it spined faster and longer. Then we chose the anode material as support to prepare electrolyte membrane. The thickness of the electrolyte membrane increased with the increase of the number of layers. Two layers were the most appropriate.
Effect of Compositions, Crystal Structures and Morphologies on Photo-Luminescent Property of LaPO4:Gd3+
Authors: Zhang Luo , Wang Xiao Yan , Wang Xin , Ni Hong Tao
Published: March 2016

Various LaPO4:Gd3+ samples were synthesized by the hydrothermal method under different conditions to investigate the influence of crystalline structures, compositions and morphologies on the photo-luminescence. The compositions, crystal structures and morphologies were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and photo-luminescence emission spectrum (PL). The results revealed that the emission intensity of LaPO4:Gd3+ reached the maximum value as the mass percentage concentration of Gd3+ ions ascended to 3%. Monoclinic LaPO4:Gd3+ had stronger emission intensity than hexagonal sample which had more zeolitic water, higher symmetry and lower crystallinity. The nanospheres which dispersed better and had higher uniformity and surface atom fraction had the stronger PL intensity than the nanorods. It has been found that the La0.97Gd0.03PO4, which was prepared under the condition of pH=1, T=20 °C and excess PO43-, performed the best PL property after heat treatment at 900 °C for 4h.
Thermal Conductivity of Polyimide Resin-Based Composite with Cu Fibers
Authors: Zhang Dan , Wang Shuang Xi , Liu Gao Shan , Wang Wen Jun , Xiao Feng
Published: March 2016

In some industrial application, thermal property of resin plays an important role as same as strength. Many attempts have been made to enhance the thermal conductivity of resin matrix composite. In this paper, the copper fibers were introduced to the polyimide-based composite. The experimental results showed that the thermal conductivity of polyimide-based composite with 15% Cu fibers was as high as 8.62W/mK which is more than three times that with Cu powders. The PI-Cu composites with copper fiber had a much lower wear loss than that with copper powder. The forming of three-dimensional network by Cu fibers makes it possible that the heat can conduct by electrons in the resin-based composite with Cu fibers.
DFTB Calculation of Si Atomic Chains’ Structures and Electronic Properties
Authors: Xu Xiu Min , Wu Li Jun , Zhang Lin
Published: March 2016

In this paper, structures and electronic properties of atomic chains with 5 to 20 silicon atoms and different atomic distances (d = 1.652 ~ 2.752Å) were calculated by the tight-binding method based on density functional theory. The results showed that the majority of the silicon atomic chains were symmetrical structures. When the number of silicon atoms was small, the silicon atomic chains were linear, when the silicon atomic chains had seven or more silicon atoms zigzag structures appeared. With the increase of the distance between atoms, atomic chains were gathering. When the number of silicon atoms was between 10 and 20, the charges on the silicon atoms appeared as a symmetrical distribution. With the increase of the number of atoms, the energy of silicon atomic chains decreased gradually. As the distance between atoms and atomic number changed, HOMO (highest occupied molecular orbital electrons) -LUMO (lowest unoccupied molecular orbital electrons) energy gap changed as well.
Determination of Gelation Kinetic Parameters for a Chitosan/β-Glycerophosphate Injectable Hydrogel by Means of Rheological Measurement
Authors: Wang Qian Qian , Chen Da Jun
Published: March 2016

The aim of the current study was to improve the knowledge of the gelation process of injectable thermosensitive hydrogels comprising chitosan (CS) and β-glycerophosphate disodium salt (β-GP). The sol-gel transition process was precisely tracked by means of rheological measurement, in which the viscosity changed considerably with gelation time and temperature. The zero-order kinetics model was assumed to adequately describe the extent of gelation reaction. The reaction rate constant increased continuously with the increasing temperature and β-GP concentration. According to Arrhenius equation, the activation energies of gelation reaction for the chitosan injectable hydrogels were calculated as 64.38 KJ/mol, 101.68 KJ/mol and 140.92 KJ/mol for the samples containing 4% w/v, 6% w/v and 8% w/v of β-GP, respectively. It could be an effective way to study the gelation dynamics of injectable hydrogels, and provide references for clinical practice.
Effects of High-Energy Ball Milling Time on the Sintering Process of FeSe Superconductors
Authors: Zhang Sheng Nan , Ma Xiao Bo , Liu Ji Xing , Feng Jian Qing , Li Cheng Shan , Zhang Ping Xiang
Published: March 2016

FeSe superconducting bulks were prepared with high energy ball milling (HEBM) aided sintering process, within which process, tetragonal β-FeSe superconducting phase could be formed directly with one step sintering process, and the formation of hexagonal δ-FeSe non-superconducting phase was effectively avoided. The influences of HEBM time on the sintering process of FeSe bulks were systematically investigated. With different HEBM time, the phase composition and morphology of precursor powders changed correspondingly, which thus influenced the final phase composition and superconducting properties of FeSe superconducting bulks. Due to the formation of FeSe bulks with larger tetragonal phase content and higher superconducting transition temperature, HEBM time of 6.0 h was recognized as the optimal parameter. Shorter HEBM time could lead to the insufficient decrease of particle size and low density. While longer HEBM time caused the formation of amorphous hexagonal δ-FeSe, which crystallized during sintering process. Thus no more tetragonal FeSe could be obtained. The FeSe superconducting bulk with the critical temperature Tc(onset) of 8.0 K was obtained with the HEBM time of 6 h, and sintering temperature of 700 oC for 12 h.
Thermal Expansion, Magnetic and Electrical Properties of Ternary Compound DyCo0.67Ga1.33
Authors: Liang Liu Qing , Zeng Ling Min , Liu Shu Hui , Li De Gui , Qin Ming
Published: March 2016

The ternary compound DyCo0.67Ga1.33 was synthesized and the thermal expansion of DyCo0.67Ga1.33 was studied in the temperature range of 309–608 K by high temperature powder X-ray diffraction technique. The volumetric coefficient of thermal expansion, , can be represented by . Its magnetic properties were measured between 30 and 300 K, and the magnetic susceptibility of DyCo0.67Ga1.33 was found to follow the Curie–Weiss law in the temperature range of 40–300 K. The effective magnetic moment and paramagnetic Curie temperature were estimated to be 9.86 μB and 40.4 K, respectively. Electrical resistivity of the compound DyCo0.67Ga1.33 was also measured between 5 and 300 K. Temperature variation of the electrical resistivity suggests the metallic character of the compound DyCo0.67Ga1.33 with an anomaly detected at 45 K. The residual resistivity ratio RRR of the compound is about 1.2.
Nano-Cu/Low-Density Polyethylene Composites: Structure and Control Release of Cupric Ions
Authors: Qiu Yu , Lei Hua , Xu Tao
Published: March 2016

In recent years a new type of intrauterine device (nanoCu/LDPE composites) has been concerned by a lot of scholars for its short release time, high bioavailability and good biocompatibility. In this study nanoCu/low-density polyethylene composites were prepared by extruding mixtures of pure LDPE and nanoCu using melt-blending method, the release rate of cupric ions (Cu2+) was measured in simulated uterine fluid. The non-isothermal crystallization behavior and thermal stability of the composites before and after immersion were studied by differential scanning calorimetry (DSC) and thermogravimetric analyzer (TG). The results showed that Composites effectively shorten the time of the copper ion "burst release" , the burst release phenomenon of Cu2+ occurred during the first five days after immersion , and then tend to stable . By immersion the crystallinity of composites increased, and the thermal stability decreased.
Structure and Performance of PP Porous Membrane Prepared with Adipic Acid and NA-40 as Nucleating Agent via TIPS
Authors: Xuan Hui Xia , He Chun Ju
Published: March 2016

Polypropylene (PP) membranes were respectively prepared using adipic acid (APA) and Sorbitol (NA-40) as nucleating agent via thermally induced phase separation (TIPS) method. The effects of nucleating agent content and cooling temperature on the structure and performance of membrane were investigated using scanning electron microscopy (SEM), wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). WAXD spectrogram indicates that three kinds of α, β and γ-form crystal were formed in this preparation process and the relative content of β-form crystal in membrane prepared by NA-40 system is higher than that of membrane formed by adipic acid. SEM images show that porous structure and cellular structure were observed on the surface and cross-section of membrane. The water flux, tensile strength and elongation increase with the addition of nucleating agent content and decrease with cooling temperature rising. This paper aims to choose proper nucleating agent NA-40 and coagulation temperature to improve the properties of PP membranes.
In-Plane Strain Field Sensor Based on the Semiconductor Film
Authors: Song Ming , Wang Hui , Xu Tong
Published: March 2016

The ZnO semiconductor multicrystalline film is utilized as the sensing material, and a sensors array is demonstrated in this paper. Based on the coupling effect of piezoelectric and semiconducting, an ultra-high sensitivity to the deformation is obtained that the gauge factor of the single units is derived up to 199, which is 100 times of that of the commercial foil gage (gauge factor = 2). After calibration on every sensing unit, the distribution of the uniform and non-uniform strain applied on the device is measured and mapped by the sensors array successfully. The results show a good application of the device on the deformation field sensing by contact test method.
High Dielectric Constant of Silver Nanowires–Epoxy Composites
Authors: Chen Yue Guang , Wang Shi Jiao
Published: March 2016

Silver nanowires–epoxy composites were prepared via cryomilling dispersion and hot-press forming process. The microstructure of the silver nanowires was studied by SEM. Dependence of dielectric properties of the composites on volume fraction of silver nanowires and frequency was investigated RF impedance material analyzer. The percolation threshold of the composites was 0.16, the value of the dielectric constant of the composite was as high as 100.
Fabrication and Characterization of Micro-Dent Produced by Laser Shock Peening on Zr-Based Bulk Metallic Glass
Authors: Zhu Yun Hu , Fu Jie , Zheng Chao , Ji Zhong
Published: March 2016

A Zr41.2Ti13.8Cu12.5Ni10Be22.5 (vit1) bulk metallic glass was processed by Nd: Glass laser pulses with duration 30ns and energy in the range 20 to 30J. The surface morphology and surface micro-hardness of the vit1 metallic glass, treated with varying laser energy, had been studied in detail. Laser shock peening induced plastic deformation and caused a micro-dent to be generated on the vit1 surface. The optical profiling tests showed that laser pulse energy greatly influenced the diameter and depth of the micro-dents. The surface roughness which was caused by various laser pulse energy was assessed and characterized. The three-dimensional surface topography of the laser treated region on vit1 surfaces had been characterized. In addition the plastic deformation features were also studied.
Effects of Briquette Forming Condition on the Extraction of Magnesium from Calcined Magnesite via Vacuum Aluminothermic Reduction
Authors: Li Xue Feng , Liu Yu Qin , Li Hui , Jiang Yun , Ma Hong Wen
Published: March 2016

Vacuum aluminothermic reduction of magnesia is multi-phase chemical reaction and the briquette forming condition has a great influence on the extent of the reactions. This paper focused on the effect of briquette forming condition on the extraction of magnesium from calcined magnesite. Briquettes were prepared at different conditions, including two forming pressures, four briquette thicknesses and two briquette diameters. The reduction ratio was calculated from the weight loss of the briquette before and after thermal reduction. The obtained condensed magnesium and briquette residues were mainly characterized via X-ray diffraction analysis and scanning electron microscopy. It was revealed that the briquette preparation condition had a great influence on the reduction ratio of magnesia and the phase constitution of the briquette residues, but had a minor influence on the morphology of condensed magnesium.
Microstructural Development around Crater in Commercial Pure Titanium
Authors: Li Ying Chao , Li Bo Long , Wang Tong Bo , Wang Zhen Qiang , Nie Zuo Ren
Published: March 2016

The commercial pure titanium plate was shot vertically by the projectile with a diameter of 7.62mm at impact velocities ranging from 782m/s to 825m/s. The microstructure around the crater of commercial pure titanium plate was analyzed by optical microscopy (OM) and electron backscatter diffraction (EBSD) methods. It was found that different microstructures were observed along the depth of cater. In upper region of the crater, grains were deformed and fragmented. Adiabatic shear bands (ASBs) were observed in the middle of the crater, and some ASBs were bifurcated. At the bottom of the crater, the grains were less deformed, and the deformation twins were formed. The microstructures in the center of adiabatic shear band were mainly consisted of the dynamic recrystallization grains and sub-grains. The microstructure in the transition region was elongated grains along the shear stress distribution.
Effects of Stress-Relief Annealing on the Residual Stress and the Microstructure of TA15 Welded Joint
Authors: Ma Teng , Song Xiao Yun , Ye Wen Jun , Hui Song Xiao , Liu Rui
Published: March 2016

The effects of stress-relief annealing on the distribution of residual stress and on the microstructure of TA15 (Ti-6.5Al-2Zr-1Mo-1V) alloy joints by electron beam welding (EBW) were investigated. The results indicated that the microstructure of welded joint presented a transitional change, i.e. basket-weave structure appeared in the fusion zone while equiaxed α structure in base metal. No significant change occurred in microstructure after annealing at 650°C for 2 h. The residual stress in fusion zone was mainly tensile stress and the maximum longitudinal stress value was 473MPa. After annealing, the residual stress near the welded joint exhibited a uniform distribution and the maximum stress droped to 150 MPa. The yield stress and tensile stress of the TA15 welding zone were 1016 MPa and 1100 MPa respectively.
Microstructure and Mechanical Properties of TiNiFe Shape Memory Alloys with Different Compositions
Authors: Li Yan Feng , Feng Xue , Mi Xun Jun , Yin Xiang Qian , Kang Xiao Yu
Published: March 2016

The microstructure and mechanical properties of TiNiFe alloys with different compositions was investigated by tensile test, X-ray diffraction, EBSD, SEM, and TEM. The results indicated that tensile strength rapidly increased with increasing Ni content. In addition, Ti2(Ni,Fe) particles were observed in the TiNiFe alloys, which affected the mechanical properties. Increasing the content of Ni had little influence on the grain size of TiNiFe alloys. With the replacement of Ni by Fe, the lattice constant of TiNiFe alloys decreased as the Ni content increased.
Effects of Aging Temperature on the Microstructure and Mechanical Properties of a Ti2AlNb Based Alloy
Authors: Zhou Yi , Cao Jing Xia , Huang Xu , Wang Bao , Mi Guang Bao
Published: March 2016

Effects of aging temperature on microstructure and room temperature mechanical properties of solid solution treated Ti2AlNb based alloy have been investigated. The experimental results showed that after solution treatment and subsequently aging at different temperatures, all the alloys had β/B2, α2 and O three phases, which formed a typical bimodal microstructure with primary α2/O particles and acicular O precipitates dispersing within β/B2 matrix. With increasing the aging temperature, the acicular O precipitates decreased in amount but slightly increased in dimension; the particle α2/O phase did not change in amount but varied in structure, which changed into a core-shell morphology with an α2 core and a rim-O shell, and the rim-O shell was thickened; the change of microstructure led to the decrease in room temperature strength while slight improvement in plasticity. During the tension test, the cracks prefered to propagate along the prior β/B2 grain boundaries which were weaken by the necklace primary α2/O particles.
Hot Deformation Behavior and Processing Map of 25%SiCp/2009A1 Composite
Authors: Wei Shao Hua , Liu Yan Qiang , Nie Jun Hui , Zuo Tao , Ma Zi Li , Fan Jian Zhong
Published: March 2016

The hot deformation characteristics of 25%SiCp/2009A1 composite fabricated by powder metallurgy route were studied by thermal compaction testing on Gleeble-3800 hot-simulation machine in the temperature range of 370~520 °C and strain rate range of 0.01~10 s-1. The processing maps of 25%SiCp/2009A1 composites were developed on the basis of dynamic material model. The results show that the flow stress decreased with increasing deformation temperature at a constant strain rate, and increased with increasing strain rate at a constant temperature. The processing maps present unsteady zones at high strain rate (≥1 s-1). There are a few interfaces of particle-matrix separated and the particle itself cracked. There was significant dynamic recovery and dynamic recrystallization occurred in the higher temperature and lower strain rate region. The optimum hot deformation condition of the composites attained by the maps were in the temperature range of 450~490 °Cand in the strain rate range of 0.01~0.1 s-1.
Partition Behavior of Ni between γ and γ' Phases in the New Type Co-Based Superalloys
Authors: Yang Shu Yu , Wang Shuang Hong
Published: March 2016

The phase equilibria of Co-Al-W-30Ni-2Cr (at. %) alloy was established at both 900 °C and 1000 °C. The partition coefficients of Ni between the γ and γ' phases of Co-Al-W-Ni-2Cr alloys with different Ni contents were calculated at 1000 °C. The partition coefficient increased with increasing Ni content when the Al/W ratio was fixed. The maximum values of the partition coefficient was achieved at the Al/W ratio of 2.8 when the Ni content are 20, 30 and 40 at. %, respectively. The precipitation behavior of γ' phase in the Co-Al-W-30Ni-2Cr alloys with the Al/W ratio 2.8 was also investigated. The γ' phase began to precipitate at 1160 °C.