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中国高校科技期刊研究会(原中国高等学校自然科学学报研究会)
西安交通大学学报编辑部维护()，陕西新趋势()开发设计
ICP备案号/经营许可证号：陕ICP备号万方数据知识服务平台期刊资源更新-武汉理工大学学报（材料科学版）（英文版）
The Self-assembling and Application of Inorganic Antibacterial Material Made of Natural Nanoporous Carrier
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SUN Chunbao|ZHOU Beihai|DING Hao|ZENG Dongdong
The inorganic antimicrobial material was inhibited to the microbes with the added metal ion,Zn.The primary wet product carrying 5%-10% zinc ion was generated under the following conditions:temperature was 95℃,solution zinc concentration was 1.2-2.0 mol/L,and the ratio of Zn solution to zeolite weight was 5:1.The final stable product was manufactured after baking in an oven for 1-3 h at the temperature of 500-900℃.The baked material was tested for its disinfection effectiveness and coloring effect when mixed with paint coating.Based on the final batch of tests,the zinc content of this anti-microbial product was further optimized.
The Properties of YSZ Electrolyte Sintering at 1300℃
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HAN Minfang|TANG Xiuling|SHAO Wu
The properties of yttria stabilized zirconia(YSZ) related to the sintering process were discussed.YSZ nano-powders about 40-100 nm as raw material,the sub-micrometer grain sizes such as 0.4-3 μm in YSZ were gotten by sintering process at 1300 ℃,which was performed at 1000 ℃ for 2 h,then raised the temperature at the rate of 50 ℃/h to 1400 ℃,then decreased directly to 1300 ℃ in 30 minutes,finally at 1300 ℃ for 5-20 hours.The ratio of bigger grain size becomes larger as the holding time increasing at 1300 ℃.The grains less than 1 μm are about 50%,eg,43.2%,52.2% and 51.1% related to 1300 ℃ holding 5 hours,8 hours and 10 hours,respectively.As YSZ grain size became small,the electrical conductivities did not decrease,even increased,about 0.20 s/cm at 1000 ℃.The reduced sintering temperature and time were benefited to co-fire with the electrodes in electrode-supported SOFCs.
Facile Route to Prepare TaC,NbC and WC Nanoparticles
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DU Yinxiao|LEI Ming|YANG Hui|WANG Xuefei
By a novel solid-state reaction process using amorphous C3N4 (a-C3N4) and transition metal oxides as starting reagents,cubic TaC,NbC and hexagonal WC nanoparticles were successfully synthesized at 1150 ℃.The products were characterized by power X-ray diffraction (XRD),field-emission scanning electron microscope (FE-SEM),energy-dispersive X-ray spectroscopy (EDX),transmission electron microscopy (TEM) and high-resolution TEM (HRTEM).The experimental resuits show that a-C3N4 obtained by the reaction between C3N3Cl3 and Li3N is a highly efficient carburation reagent and the transition metal oxides are completely transformed into the corresponding metal carbide nanoparticles at 1150 ℃,respectively,which is significantly lower than that reported for the traditional preparation of carbides,typically＞ 1600 ℃.The TaC,NbC and WC nanoparticles are found to have an average particle size of 10 nm,15 nm and 8 nm by TEM observation,respectively.
Growth Mechanism and Characterization of ZnO 3D Nanocrystals by Laser Irradiation & Coaxially Transporting O2
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LUO Kaiyu|LI Boquan|ZHANG Huanyan
Different three-dimension (3D) nanotetrapods,containing club-like nanocrystals,nanotetrapods and four-foot-like nanocrystals were synthesized from Zinc sheet via CO2 laser irradiation and coaxially transporting O2.Different nanoproducts were fabricated by changing the content of oxygen in the experiment.The morphologies,components,phase structures and optical properties of the products were investigated by a field-emission scanning electron microscopy,an X-ray diffraction,an energy dispersed X-ray spectrometer and a photoluminescence spectroscope.The X-ray diffraction spectra were obtained on a Rigaku D/max 2500PC diffractometer.The experimental results reveal that high quality ZnO nanotetrapods can be fabricated on the special parameters,and growth of ZnO nanotetrapods depends on Vapour-Liquid-Solid(VLS) model,and the content of oxygen in the gas,namely,oxygen partial pressure is one of main factors to control morphologies and optical properties of ZnOthese advantages above are important for realization of optoelectronic devices.
Structure and Photoluminescence of Mullite.Ge Nanocomposite
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GAO Le|WANG Hao|WANG Weimin|FU Zhengyi
Al12Si3.75Ge0.25O26 ceramic powder was prepared by sol-gel method using Al(NO3)3,Si(OC2H5)4 and Cl3GeCH2-CH2COOH as precursors.The structural formation of Al12Si3.75Ge0.25O26 ceramic powder was analyzed by XRD.After reduction by flowing H2/Ar mixture gas,strong room temperature photoluminescence (PL) can be observed at 565 nm,613 nm,682 nm,731 nm and 777 nm,respectively.The PL intensity scarcely depends on the reduction temperature and duration,while the sample reduced at 500 ℃ for 3 hours has the highest PL intensity.Before and after reduction at 500 ℃,the volume of unit cell of mullite solid solution decreases to 0.4699 (A)3.Based on the analysis of XPS and Raman spectra,it can be approved that the PL phenomenon at room temperature is caused by the embedded Ge nanoparticles with the average size of about 1.95 nm.
Banded Spherulites Grown from Poly(trimethylene terephthalate) Solution-cast Film
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HE Xingquan|YANG Decai
Various morphologies of poly(trimethylene terephthalate) (PTT) solution-cast thin films at different crystallization temperatures were investigated by polarized light microscopy (PLM),atomic force microscopy (AFM) and transmitted electron microscopy (TEM).In the range of 110-150 ℃,banded spherulite occurred and banding space gradually decreased along the radial direction from the primary nucleation site.Between 160 and 170 ℃,normal non-banded spherulite was found.Above 170 ℃,banded configuration occurred again.Lamellar growth direction of banded spherulite was determined to the crystal a-axis.
Photopolymerization of Glycerin Triglycidyl Ether Based Systems
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HUANG Biwu|CHEN Yiwang|DENG Qilan
Photopolymerization process of glycerin triglycidyl ether based systems was studied by an FT-IR spectrometer.An increase in the rate of polymerization for glycerin triglycidyl ether was evident when 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate was added to it.Its copolymerization mechanism was confirmed by using DSC analysis.The effect of ethoxylated trimethyol propane triacrylate on the rate of polymerization for glycerin triglycidyl ether was also studied,and the formation of interpenetrating network tightly cross-link was proposed.
Electronic Band Structures of TiO2 with Heavy Nitrogen Doping
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XUE Jinbo|LI Qi|LIANG Wei|SHANG Jianku
The first-principles density-functional calculation was conducted to investigate the electronic band structures of titanium dioxide with heavy nitrogen doping (TiO2-xNx).The calculation results indicate that when x≤0.25,isolated N 2p states appear above the valence-band maximum of TiO2 without a band-gap narrowing between O 2p and Ti 3d states.When x≥0.50,an obvious band gap narrowing between O 2p and Ti 3d states was observed along with the existence of isolated N 2p states above the valence-band of TiO2,indicating that the mechanism proposed by Asahi et al operates under heavy nitrogen doping condition.
A Single-phase of Supercritical CO2/Polystyrene Solution in Foam Extrusion
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WU Xiaodan|CENG Haohua|CAI Yiebin|PENG Yucheng
The high quality single-phase solution of CO2/Polystyrene was achieved,by analyzing the influential factors for polymer microcellular foaming extrusion.The curve of pressure distribution along the barrel was determined.The axial position of gas-injecting port on the barrel was chosen form the results of stable foaming,and the number of gas-injecting ports in the circumference of the barrel was determined from the CO2 solubility in polymer.The effect of the screw rotation speed on CO2 solubility was studied,and the effects of pressure difference between the gas and the polymer melt on gas-injecting process and on the foaming stability were investigated.The influence of the gas temperature before injection on the single-phase of CO2/Polystyrene solution also was studied.
Hemoglobin-biocatalyzed Synthesis of Conducting Molecular Complex of Polyaniline and Lignosuifonate
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HU Xing|LIU Shenggui|ZHAO Mingming|ZOU Guolin
A new biocatalyst route for the synthesis of a conducting polyaniline (PANI)/lignosulfonate (LGS) complex was presented.Four different catalysts such as hemoglobin (Hb),5,10,15,20-tetrakis (meso-hydroxyphenyl) porphyrin,iron (Ⅱ) tetrasulfophthalocyanine and ferric chloride were used to polymerize aniline in the presence of a natural polyelectrolytes template LGS.The experimental results show that Hb is an effective catalyst in this case and the synthesis is simple,and the conditions are mild in that the polymerization may be carried out in lower pH (1.0-4.0) buffered solution and optimal pH of 2.0.Varying concentrations of aniline,LGS and H2O2 in feed the favorable conditions for the production of PANI were determined.UV-vis absorption,FFIR,elemental analysis,conductivity,cyclic voltammetry and thermogravimetric analyses confirm the formation of thermally stable and electroactive PANI.
Preparation and Swelling Behavior of Physically Crosslinked Hydrogels Composed of Poly(vinyl alcohol)and Chitosan
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HE Guanghua|ZHENG Hua|XIONG Fuliang
The physically crosslinked poly(vinyl alcohol)/chitosan (CS) composite hydrogels were prepared by cyclic freezing/thawing techniques,and the microstructure and swelling behavior of the hydrogels in the simulated gastric (pH 1.0) and intestinal (pH 7.4) media were investigated.The experimental results of infrared spectra (IR),scanning electron microscope (SEM) and differential scanning calorimetry (DSC) demonstrated that poly(vinyl alcohol) and chitosan had good miscibility in the composite hydrogels,and the addition of chitosan perturbed the formation of poly(vinyl alcohol) crystallites.The swelling kinetics results indicated that the composite hydrogels had good pH sensitive properties to the acidic environments,and with the increase of chitosan content in the blend,the maximum swelling degreed and the swelling rate both increased,but it led to more dissolution at pH 1.0.And the composite hydrogels also exhibited good reversible swelling behavior with pH value of the swelling medium altering between 1.0 and 7.4.In addition,the higher freezing/thawing cycle times resulted in the lower swelling rate.Therefore,the swelling behavior of the composite hydrogels could be adjusted by changing the chitosan contents and the freezing/thawing cycle times.
Ethylene Polymerization by a Novel Dinuclear Heteroligated Titanium Complex with the Ligand of (Salicylaldiminato)(β-enaminoketonato)
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NIE Yujing|SUN Junquan|CHENG Zhengzai|WANG Lineai
The condensation of acetylacetone (CH3COCH2COCH3) with benzdine(H2N-C6H4-C6H4-NH2) yielded diimine ligand 1 [HOC(Me)C(H)(Me)C=N(p-C6H4)(C6H4-p)N=C(Me)C(H)C(Me)OH)],which was converted into sodium salts.And then the sodium salts reacted with monosalicylaldiminato titanium complex 2{[3,5-di-Bu'-240)C6H2CHN(PH)]TiCl3(THF)} in dried dichloromethane to give a new benzdine-bridged binuclear complex 3{[3,5-di-Bu'-2-(O)C6H2CHN(PH)]2[OC(Me)C(H)(Me)C=N(p-C6H4)-(C6H4-p)N=C(Me)C(H)C(Me)]Ti2Cl4}.The complex 3 was characterized by 1HNMR and elemental analysis.In the presence of MAO(methylaluminoxane),the complex 3 in toluene was effective to catalyze polymerization,affording moderately high catalytic high temperature gel permeation chromatography (GPC) curve of polyethylene obtained revealed a single peak,but the molecular weight distribution (MWD=3.21) is obviously broader than that of the similar mononuclear titanium complex.The melting points of the obtained polyethylene reaches 138 ℃,indicating that the polyethylene is of high crystallinity.
Effect of Thermal Crosslink Conditions on Dynamic Mechanical Behaviors of Flexible Epoxy
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DAI Ping|WANG Yanbing|HUANG Zhixiong
The dynamic mechanical behavior of a new kind of flexible epoxy FE-1,which was crosslinked under four different thermal crosslink conditions,was studied.Dynamic mechanical measurement was carried out from 10 ℃ to 120 ℃,and loss factor,tan δ and the storage modulus as functions of temperature were presented under five different frequencies of 0.1 Hz,1 Hz,5 Hz,50 Hz and 100 Hz.The experimental results show that temperature has dramatic effects on the dynamic mechanical behavior of pared with other common available epoxy,the flexible epoxy has higher loss factor over broad frequency and common temperature range.Activation energy corresponding to glass transition process of FE-1 was calculated from the temperature corresponding to tan δmax values,obtained at different measurement frequencies.The maximum value of loss factor is 0.75 and the Tg varies from 6 ℃ to 50 ℃,indicating the flexible epoxy can be used as damping polymer materials at common temperature or frequency range.
The Synthesis Technique of Polyacrylic Acid Superplasticizer
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ZHANG Rongguo|LI Qiong|ZHANG Anfu|LIU Yong|LEI Jiaheng
Using water separation technique,acrylic acid (AA) and polyethylene glycol (PEG) 1000,of which the ratio was 1.5,were esterified and the optimum esterification ratio of 90% could be reached under the condition of 110 ℃×3 h.Using polyoxyethylene acrylate macromonomer (PA) prepared in the esterification,AA and sodium methylacryl sulfonate (MAS) as monomers,a copolymer which could be used as superplasticizer was prepared by free radical copolymerization in n(PA);n(AA) :n(MAS) of 1 ;7 :3.When the synthesis condition was 80 ℃×5 h,the optimal dosage of initiator was 3.0%-4.0%,the fluidity of cement paste with the samples could reach 270 mm.By analyzing the effect of the content of residual small molecule sulfonic monomer on the properties of sample,n(MAS)/n(PA) was controlled in a range of 2.5-3.8.
Synthesis,Characterization and Catalytic Properties of Mesoporous HPMo/SiO2 Composite
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YAN Xuemin|YAN Jiabao|MEI Ping|LEI Jiaheng
A novel mesoporous HPMo/SiO2 composite was synthesized by the sol-gel method with triblock copolymer EO20PO70EO20 as template.The properties of the product were characterized by X-ray diffraction,transmission electron microscopy,N2 adsorption-desorption isotherms,Fourier transform infrared spectrometer and inductively-coupled plasma analysis.The experimental results show that the product has a very ordered hexagonal mesostructure,and the HPMo is immobilized into the framework of silica.The final mesoporous composite shows excellent stability in polar solvents.Results of catalytic tests indicate that the composite is an effective catalyst for oxidation of dibenzothiophen,and there are few activity losses even after the third cycle of uses.The high catalytic activity and good insolubility make it a promising catalyst in oxidative desulfurization process.
Residual Monomer Content and Its Release into Water from the Denture Base Nanocomposite Using Organic Montmorillonite as Reinforcement
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LI Hongbo|ZHANG Chao|LI Zhian|WANG Yining|XIAO Qun
A novel kind of denture base nanocomposite was prepared by polymethyl methyacrylate(PMMA) and cethyltrimethylammonium bromide modified organic montmorillonite (OMMT).The dispersion of montmorillonite in the polymer matrix was characterized by x-ray diffraction (XRD) and transimission electron microscope (TEM).The content of residual MMA in nanocomposites and the amount of MMA released to water from nanocomposites were determined by gas chromatography (GC).The analysis of TEM and XRD showed that exfoliated-intercalated and intercalated nanocomposites were formed when the content of OMMT was 3% and 5% in the PMMA powder respectively.The results of GC showed that the residual MMA increased with the increase of OMMT content in the polymer matrix.After 7 days in water,the amount of MMA released into water from the nanocomposites tended to be stable.The results of one-way ANOVA and t-test showed that OMMT gave a significant increase of residual MMA concentration (p＜0.05) in nanocomposites.
Precipitation and Hetero-nucleation Effect of V(C,N)in V-Microalloyed Steel
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LI Xineheng|ZHAO Liangyi|WANG Xinyu|ZHAO Yutao
The precipitation behavior of V(C,N) in steels microalloyed with vanadium was researched using a thermal simulator during single-pass deformation at 800-750 ℃.The V(C,N) precipitates and its nucleation effect on ferrite were investigated by TEM and EDS.The experimental results show that there are two remarkable heterogeneous nucleation effects of V(C,N) particles precipitated before y→αphase change:primary reason is that high coherency between V(C,N) and ferrite promotes V(C,N) to become a nucleating center of isecondary reason is that the coarsening of V(C,N) causes locally solute-poor region in austenite,thus expedites the nucleation of intragranular ferrites further.Furthermore,the relationship between the size and shape of V(C,N)was studied,and identification method was provided for distinguishing interphase precipitation and general precipitation to avoid erroneous judgment and misguide.
Characteristic Surface Oxide Film Cracking Behavior of a Fe-Ni-Cr Alloy under In-phase and Out-of-phase Thermo-mechanical Fatigue
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The surface oxide film cracking behavior of Fe-30Ni-20Cr alloy under in-phase and out-of-phase synchronizing thermal cycling with mechanical cycling was studied.Surface oxide film cracking along the grain boundary under in-phase overlapping was creep predominant fracture mechanisms.Strongly induced slip lines preceding were accompanied by the surface oxide film cracking under Out-of phase,and the shear cracking wa~ dominant mode.Negative mean stress could counteract a part of the tensile component of alternative stress,so as to delay the cracking process under in-phase,but positive mean stress overlapping the tensile alternative stress could accelerate the cycling cracking process under out-of-phase.
As-cast Microstructure,Mechanical Properties and Casting Fluidity of ZA84 Magnesium Alloy Containing TiC
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YANG Mingbo|CHENG Liang|BAI Liang|PAN Fusheng
The as-cast microstructure,mechanical properties and casting fluidity of ZA84 alloy containing TiC were investigated.The experimental results indicate that adding 0.5wt%TiC to ZA84 alloy can refine the as-cast microstructure,and do not cause the formation of any new phase.After 0.5wt%TiC was added to the ZA84 alloy,the morphology of ternary phases on the grain boundaries changed from coarse quasi-continuous net to fine disconnected net,and the distribution of ternary phases became dispersive and homogeneous.At the same time,the tensile properties of ZA84+0.5TiC alloy at room temperature were comparable to those of AZ91D alloy,and were higher than those of ZA84 alloy.At 150 ℃,the tensile and creep properties of ZA84+0.5TiC alloy were also higher than those of ZA84 and AZ91D alloys.In addition,compared with the AZ91D alloy,the casting fluidity of ZA84+0.5TiC alloy was slightly poor,but better than that of ZA84 alloy.The reason could be related to the effect of TiC on the solidification temperature range of ZA84 alloy.
Phase Structure and Electrical Properties of La2O3-doped BiInO3-PbTiO3 Ceramics with High Curie Temperature
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Li Zhaofeng
The phase structure and electrical properties of pure and La2O3-doped BiInOa-PbTiO3 (BI-PT) ceramics were studied respectively.In (1-x)BI-xPT (x=0.72-0.80) ceramics,the stability of tetragonal phase increased with increasing x,and pure perovskite structure was obtained for x=0.80 ceramics.The phase transition temperature range was between 575 ℃ and 600 ℃for x=0.72-0.80 ceramics,higher than that of PT (～490 ℃).The c/a ratio almost linearly decreased with increasing La2O3 content in x=0.80 ceramics.It is believed that Pb2+ vacancies were formed by La3+ substituting Pb2+ in La2O3-doped BI-PT ceramics.Tc shifted to lower temperature by 30 ℃/mol% La2O3.The maximum dielectric constant 8557 around 559 ℃ was exhibited in 0.5mol%-doped BI-0.80PT ceramics.La2O3-doped ceramics could be poled resulting from decreasing of c/a ratio and improving of dielectric loss and resistivity.The maximum piezoelectric coefficient d33 was 12 pC/N for 2mol%-doped BI-0.80PT ceramics.
Synthesis of Ti3SiC2/TiB2 Composite by In-situ Hot Pressing (HP) Method
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ZHOU Weibing|MEI Bingchu|ZHU Jiaoqun
Ti3SiC2/TiB2 composite was successfully obtained by hot pressing Ti/TiC/Si/B4C power mixtures.Volume fraction of TiB2 in Ti3SiC2/TiB2 composite can not exceed 10%.Incorporation of excessive TiB2 will affect the reactions process.TiC and Ti5Si3 were two important intermediate phases during the whole reactions.The microstructure characteristics of the Ti3SiC2/TiB2 composites were analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM).The experimental results show that the grains of Ti3SiC2/TiB2 composite are structured in a layered form,and the formation of TiB2 particles as reinforcements with elongated or equiaxed shape distributes in Ti3SiC2 matrix.
Spark Plasma Sintered AIN-BN Composites and Its Thermal Conductivity
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ZHAO Haiyang|WANG Weimin|WANG Hao|FU Zhengyi
A series of samples of hexagonal boron nitride-aluminum nitride ceramic composites with different amounts of CaF2 as sintering aid were prepared by spark plasma sintered at
℃ for 5 min.The addition of CaF2 effectively lowered the sintering temperature and promoted the densification of AlN-BN composites.With the increase of sintering temperature,the density increased,and the contiguity of AIN grains enhanced in AIN-BN composites.Thermal conductivity of AIN-BN composites increased with the increase in CaF2 content and sintering temat 1800 ℃.
Synthesis and Sintering of Mg2Si Thermoelectric Generator by Spark Plasma Sintering
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YANG Meijun|ZHANG Lianmeng|SHEN Qiang
Raw Mg,Si powder were used to fabricate Mg2Si bulk thermoelectric generator by spark plasma sintering (SPS).The optimum parameters to synthesize pure Mg2Si powder were found to be 823 K,0 MPa,10 min with excessive content of 10wt% Mg from the stoichiometric Mg2Si.Mg2Si bulk was synthesized and densified simultaneously at low temperature (823 K) and high pressure (higher than 100 MPa) from the raw powder,but Mg,Si could not react completely,and the sample was not very dense with some microcracks on the surface.Then,Mg,Si powder reacted at 823 K,0 MPa,10 min in SPS chamber to form Mg2Si green compact,again sintered by SPS at 1023 K,20 MPa,5 min.The fabricated sample only contained MgESi phase with fully relative density.
Effect of Pb Substitution on the Microstructure and Ferroelectric Properties of Ba0.7Sr0.3TiO3 Ceramic
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YANG Weiming|YU Jun|LI Jianjun|ZHOU Shen|HE Jianlong
Ferroelectric Ba0.7Sr0.3TiO3(BST) and partially Pb2+ substituted for Ba2+ ceramics (Bao.7-xPbx)Sr0.3TiO3 (x=0.1-0.4,BPST) were prepared by using conventional solid-reaction method.XRD analysis shows that the samples microstructure changes from cubic phase to tetragonal one with the Pb2+ content increasing.ESEM analysis shows that the Pb2+ substituted samples have a denser and more uniform surface morphology than that of pure BST.Measured electrical properties suggest that the Pb2+ substitution for Ba2+ in the BST system enhances the ferroelectric performance obviously when x=0.2.In addition,the substitution increases the samples Curie temperature (Tc).(Ba0.5Pb0.2)Sr0.3TiO3 ceramic has good ferroelectric properties measured at a maximal electric field of 30 kV/cm under the condition of room temperature.The corresponding saturated polarization (Ps),remnant polarization (Pr) and coercive field (Ec) is respectively 15.687 μC/cm2,8.100μ C/cm2 and 6.611 kV/cm.The measured Tc of (Ba0.5Pb0.2)Sr0.3TiO3 is 117 ℃.
UV Laser Induced Transmission Change of Pure and Doped Silica Glass
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XIE Junlin|DENG Tao|LUO Jie|BAN Qingrong
Pure and F,GeO2-doped silica glass cut from fiber preforms prepared by plasma assisted chemical vapor deposition(PCVD) were investigated by ultraviolet absorption spectroscopy.The ultraviolet absorption characteristics of these glasses were also studied after UV laser irradiation and heating treatment.It was found that absorption band near 240 nm assigned to GODC was found both in GeO2-doped and F-GeO2 co-doped silica glass,but absorption intensity of the latter was lower than that of the former.It's because F can react with GODC and GeE' simultaneously and reduce their concentration.After irradiation,UV absorption change of F-GeO2 co-doped silica glass was weaker than that of GeO2-doped silica glass,it thus can be concluded that introduction of F could depress the UV absorption of GeO2-doped silica core effectively.
Effect of Heat Treatment Method on Microstructure of Tailings Glass Ceramics
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LIU Jun|OU Yang|XU Changwei|QI Hong
A Cao-Mgo-Al2O3-SiO2 quaternary system was established with the main crystal phase design based on Diopside,and the effect of once-through sintering heat treatment on microstructure of iron tailings glass ceramics was studied by using DTA,SEM along with measurement of microhardness and volume density.The experimental results show that,when the total amount of FeO and Fe2O3 exceeds 10wt%,a large number of fine nuclei are produced in the annealing process,and the phenomenon of nucleus resorption happens during the process of nucleation heat treatment,which is unfavorable for preparing iron tailings glass ceramics through once-through sintering method.When the annealing temperature from 1250 ℃ to 830 ℃,setting crystallization time for 4h,without heat treatment,crystals are well grown with arrangement and interlocking in glass phase.At 830 ℃ the crystals are well developed,well distribuwith crystallization time of 4 h the crystals with radial shape have high content and regular arrangement.
Effect of Al2O3 Content on Residual Stress and Properties of CAS Glass-ceramics
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XIE Jun|LONG Xinjiang|CHENG Jinshu|LI Hong
The structure and properties of the glass-ceramics were tested with X-ray diffraction testing instrument,correlative software,and other modern testing means.Then the effect of Al2O3 content on internal stresses in CaO-Al2O3-SiO2 glass-ceramics was studied deeply.In order to study the relationship of Al2O3 to the residual stress of CaO-Al2O3-SiO2 glass-ceramics,X-ray diffraction&sin2 ψ&was used.The means utilized the x radial incidence produced from cathode radial tube,and took the space between crystals as measurement of strain.When the stresses produced,the space between crystals changed and the diffraction peak moved during Bragg diffraction.The magnitude of movement is related to the stresses.The experimental results show the residual stress is considerably high and Al2O3 can influence the mechanical properties of this material hugely.
Durability of Concrete Subjected to the Combined Actions of Flexural Stress,Freeze-thaw Cycles and Bittern Solutions
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YU Hongfa|SUN Wei|ZHANG Yunsheng|GUO Liping|LI Meidan
Freeze-thaw durabilities of three types of concretes-normal portland cement concrete (OPC),high strength concrete (HSC) and steel fiber reinforced high strength concrete (SFRHSC)were systemically investigated under the attacks of chemical solution,and combination of external flexural stress and chemical solution.Four kinds of bitterns from salt lakes in Sinkiang,Qinghai,Inner Mongolia and Tibet provinces of China were used as chemical attack solutions.The relative dynamic modulus (RDM) was used as an index for evaluating the damage degree during the course of chemical attack and stress corrosion.The experimental results show that the freeze-thaw durability of concrete is visibly reduced in the present of the flexural stress,i e,stress accelerates the damage process.In order to quantify the stress accelerated effect,a stress accelerating coefficient was proposed.The stress accelerating coefficient is closely related with the types of bitterns and the numbers of freeze-thaw cycles is.The more numbers of freeze-thaw cycles is,the greater the stress accelerating coefficient for various concretes will be.In addition,there also exists a critical ratio of external stress to the maximum flexural stress.If the stress ratio exceeds the critical one,the freeze-thaw durability of various concretes will be greatly decreased compared to the responding concretes without applied stress.The critical stress ratio of OPC,HSC and SFRHSC is 0.30,0.40 and 0.40,respectively,indicating that HSC and SFRHSC have advantages over OPC and are suitable to use in the bittern erosion regions.
Alkali-silica Reactivity of Different Aggregates from Mineral and Textural Characteristics
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MO Xiangyin|JING Yingjie|HAN Tingli|TANG Mingshu
To identify the aggregates causing the alkali-silica reaction,and the reactivity of rocks in different parts of China,the mineral and texture characteristics of some typical coarse aggregates and the alkali reactivity of these aggregates were systematically investigated.On one hand,petrographic examination of aggregates,combined with X-ray diffraction analysis,chemical analysis,scanning electron microscopy,was conducted for analyzing their mineralogy and texture.It was found that not only mineral characteristics,but also their interior structure would affect their potential alkali-silica reactivity.Furthermore,the alkali-silica reactivity of aggregates is due to their mineral compositions,such as containing different alkali-reactive minerals,while,different stuctures of those aggregates with similar minerals affect their reactivity to some extent.There are some amount of micro-aperture and cracks across the quartz in the aggregate,which may become the natural accesses for Na+,K+,and OH ions to intrude in the mortar or concrete during the process of alkali-silica reaction.Alkali-silica reactivity of the aggregates was detected by the accelerated mortar bars test.It was revealed that all the aggregates tested were alkali-silica reactive and the results were also in accordance with their mineral and structure analysis.
Shrinkage Reducing Measures for Engineering Cementitious Composites
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YANG Yingzi|YAO Yan|GAO Xiaojian|DENG Hongwei|YU Pengzhan
Inhibition measurement of shrinkage of engineering cementitious composites(ECC) was investigated due to typical ECC with higher free drying shrinkage.The effects of expanded admixture (EA),shrinkage reducing admixture (SRA),coarse sand+stone powder (CS+SP)and superabsorbent polymer (SAP) on drying shrinkage and mechanical properties were studied.The experimental results show that ECC incorporating EA,SRA and coarse sand can retain around 60% of the typical ECC's free drying shrinkage.Superabsorbent polymerl(SAP) can delay the development of free drying shrinkage of ECC at different ages,and the effect of SAP is not distinct like the actions of EA,superabsorbent polymer(SRA) and coarse sand.Significantly,SAP may act as artificial flaw to form a more homogeneous defect system that increases the potential of saturated multiple cracking,hence the ductility of ECC will be improved greatly.
Preparation of Eco-environmental Protection Bricks from Lake Sludge
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WU Jianfeng|LI Fangwen|XU Xiaohong|SU Xianli
Eco-environmental protection hollow bricks manufactured from lake sludge collected from North Lake in Wuhan of China were investigated.At first,the recipes of round sampies(diameter in 5 cm and thickness in 1 cm) prepared by pressing molding under a pressure of 8 MPa and firing system were optimized,and properties such as bending strength,compressive strength,total shrinkage rate,water adsorption rate,apparent porosity and bulk density of the fired samples were tested.The experimental results showed that water adsorption rate and apparent porosity decreased,while bulk density increased with firing temperature increasing.Addition of additive can result in the improvement of strength of fired samples.At the same time,fly ash and additive may also broaden the firing temperature range and reduce firing temperature.Toxic characteristic leaching procedure (TLCP)tests of samples also show that the metal leaching level is low.The conditions for manufacturing good quality sample include 80% sludge with 10% additive and 10% flyash fired at 1000 ℃ for 60 min.Bending strength and compressive strength of samples prepared under the conditions are 24.64 MPa,131.95 MPa,respectively,which are far beyond the requirements of clay solid bricks of CNS.Finally,according to the optimized recipe,the eco-environmental protection hollow bricks with the sizes of 40 mm×38 mm×25 mm were made and tested by pared with the Chinese National Standards (CNS:GB ),compressive strength,water adsorption and bulk denstiy of the hollow bricks are 11.55 MPa ,14.5% and 986 kg/m3 when they were fired at 1040 ℃,which are far beyond the require of of CNS.Especially,its water adsorption arrives to standard of high-class products(16.0%) and compressive strength is above the hightest class(MU 10.0).
Healing Effectiveness of Cracks Rehabilitation in Reinforced Concrete Using Electrodeposition Method
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JIANG Zhengwu|XING Feng|SUN Zhenping|WANG Peiming
An electrodeposition method and its experimental device for rehabilitation of cracks in reinforced concrete were proposed.Porous concrete is proposed to simulate cracked concrete,and mass increment,permeation coefficient and sound velocity of ultrasonic wave were used to be evaluating indicators of healing effectiveness of crack rehabilitation in this method.Effect of currency density,concentration of electrolyte solution on healing effectiveness of porous reinforced concretes with different total void ratio was studied.The experimental results indicate that the simulation of porous concrete for cracks can reflect the healing effectiveness of electrodeposition method effectively.Total void ratio of porous concrete has little effect on healing effectiveness of electrodeposition at early ages.The higher the currency density or concentration of electrolyte solution is,the higher the electrodeposition rate and sound velocity in porous concrete are,and the lower the permeation coefficient of porous concrete will be.Mg(OH)2 crystals produced in high current density are large,thin sheet-shaped and arranged loosely.
Morphology Difference between the Alkali Activated Cement and Portland Cement Paste on Multi-scale
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SHEN Weiguo|ZHOU Mingkai|XIAO Liqi|MA Wei|CAI Zhi
The features of alkali activated slag(AAS) and portland cement (PC) were observed on multi-scale,the crack and fracture sections were observed with naked eyes,and SEM and AFM were used to study the structure morphology differences between PC and AAS on micrometer to nano meter scale.The experimental results indicated that the AAS paste had soil like fracture texture and it was composed of mainly C-S-H gel but lacks of crystals,and it had a very strong tendency to shrink and crack.AAS paste is much denser and more homogeneous than PC,and on the nano scale C-S-H nano particle in the AAS paste is much smaller and packs much denser than PC paste.
Effect of Matrix Composition on Physical Properties of Al3CON In-situ Reaction Reinforced Corundum Composite
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YANG Dingao|YUAN Shouqian|JIANG Mingxue|ZHANG Changxi|ZHENG Jianying|LIANG De'an|ZHANG Qiye
60% white corundum used for aggregate.5% aluminium powder for fixed additions and 35% various additives for matrix were prepared for specimens 1#,2#,3#.They were mixed uniformly with the suitable resin as a binder and pressed under pressure of 315 ton forging press,then dried at 200 ℃ for 24 h.Effects of various additives on 1500 ℃×2 h creep properties of Al3CON reinforced corundum composite were researched,The experimenal results show that creep coefficients of specimens 1#,2#,3# at 1500 ℃×2 h are 1.4×10-4,-9.4×10 4,-22.6×10-4 respectively.Crushing strength of the slide plate added with suitable additive A after fired at 1500 ℃×3 h reaches to 225 MPa,the creep rate is positive all the time from 0% to 0.014% at 1500 ℃ for 2 h.The microstructure result analysis shows that reinforced phases of Al3CON fiber composite have been formed after fired with Al powder in coke at high temperatures for specimen 1#,and the strength of the composite is increased.The hot modulus of rupture is up to 59 MPa at 1400 ℃ and the RUL is obviously higher than that at 1700 ℃.Its service life is two times as that of Al2O3-C slide plate when used in the process of pouring steel.The mechanism of creep rate resistance of the composites can be discovered by means of SEM and EDAX analysis.It is concluded that the active Al3CON and Al2O3 multiphases that were formed by N2 in gas,C,Al and Al2O3 inside the matrix of the composites during in-situ reaction,which gives the composites outstanding creep rate resistance for the dense zone resulting from Al3CON oxidation that inhibits contraction at the high temperature.Besides,the matrix will turn into the multiphase with high refractoriness,N content and its Al3CON reinforced fiber will further increase accordingly.In addition,Al3CON formed by Al2O3 and C,Al in the matrix with N2 in gas will inhibit the creep rate and also greatly improve the creep rate resistance of the composites.
Preparation and Recipe Optimization of Water-based Architectural Heat Insulation Coatings
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CHEN Lijun|SHI Hongxin|XIANG Juping|WU Hongke
Water-based architectural heat insulation coatings were studied to overcome the drawbacks of conventional inorganic silicate heat insulation coatings.The heat insulation coatings were prepared with the method of mechanical agitation when the mixed organic polymer emulsions were used as binder of the coatings and the mixed heat insulating aggregates were applied as powder,and some assistants were also added.Water temperature difference in the plastic container,which was coated with heat insulation coatings,represented the heat-insulating property of the coatings.The influences of components of mixed polymer emulsion,mass ratio of polymer emulsion to powder,particle size of heat insulating aggregates,added amount of air entraining admixture and the match of thickeners on the properties of the coatings were studied.The experimental results show that the heat insulation coatings with good finishing,heat-insulation property and artificial weathering can be prepared when the binder is composed of 66.92% styrene-acrylic emulsion,16.59% elastic emulsion and 16.49% silicone-acrylic emulsion,the mass ratio of polymer emulsion to powder is 0.45,the particle size of heat insulating aggregates is in the rang of 200 and 250 mesh size,the added amount of sericite is 15%,and the added amount of air entraining admixture is in the range of 1.0% and 1.5% and the thickeners are the mixtures of ASE-60 and RM-5000.
Dynamic Mechanical Behaviour of Ultra-high Performance Fiber Reinforced Concretes
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LAI Jianzhong|SUN Wei
Ultra-high performance fiber reinforced concretes (UHPFRC) were prepared by replacing 60% of cement with ultra-fine industrial waste powder.The dynamic mechanical behaviour of UHPFRC with different fiber volume fraction was researched on repeated compressive impact in four kinds of impact modes through split Hopkinson pressure bar (SHPB).The experimental results show that the peak stress and elastic modulus decrease and the strain rate and peak strain increase gradually with the increasing of impact times.The initial material damage increases and the peak stress of the specimen decreases from the second impact with the increasing of the initial incident wave.Standard strength on repeated impact is defined to compare the ability of resistance against repeated impact among different materials.The rate of reduction of standard strength is decreased by fiber reinforcement under repeated impact.The material damage is reduced and the ability of repeated impact resistance of UHPFRC is improved with the increasing of fiber volume fraction.
Properties of Leakage Corrosion of Concrete and Its Durability
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GE Xueliang|FANG Kunhe|ZENG Li|CHEN Xia
The properties and mechanism of concrete under water leakage corrosion were studied in terms of the dissolution of calcium oxide and silicon oxide from concrete and the variation of pH value of permeate water.The experimental results show that the amount of calcium oxide and silicon oxide dissolved from per cubic meter of concrete gradually decrease with penetration time and ultimately stabilize at a certain value.The pH value of permeate water descend along with penetration time.The durability of concrete under leakage corrosion was analyzed by a formula fitted on the dissolved amount of calcium oxide.
A New Method to Quickly Assess the Inhibitor Efficiency
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GENG Chunlei|XU Yongmo|WENG Duan
A new method to quickly assess the efficiency of corrosion inhibitor was developed by electrically accelerating chloride ions diffusing onto the surface of the embedded steel bar in concrete and inducing corrosion.Potentiodynamic polarization scanning and linear polarization method were used to evaluate the corrosion states which were compared with the direct observation of the bar surface by breaking the sample.The test duration was about two days and the results clearly show the differences in efficiency of the inhibitors tested.
MSWI Fly Ash Based Novel Solidification/Stabilization Matrices for Heavy Metals
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DENG Faqing|QIAN Guangren
The possibilities of MSWI fly ash as a major constituent of novel solidification/stabilization matrices for secure landfill were investigated by mixing MSWl fly ash with rich aluminum components,which was added as bauxite cement or metakaolinite instead,to form Friedel and Ettringite phases with high fixing capacities for heavy metals.The physical properties,heavy metals-fixing capacity,mineral phases and its vibration bands in the novel matrices were characterized by compressive strength,TCLP(toxic characteristic leaching procedure),XRD (x-ray diffraction),DTG (derivative thermogravimetry),and FTIR (fourier transform infrared spectroscopy),respectively.The Tessier's five-step sequential extraction procedure was used to analyze the fractions of chemical speciation for Pb,Cd and Zn ions.The experimental results indicate that Friedel-Ettringite based novel solidification/stabilization matrices can incorporate Pb,Cd and Zn ions effectively by physical encapsulation and chemical fixation,and it exhibits a great potential in co-landfill treatment of MSWI fly ash with some heavy metals-bearing hazardous wastes.
A Novel Traveling Wave Ultrasonic Motor Using a Bar Shaped Transducer
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JIN Jiamei|ZHAO Chunsheng
A novel traveling wave ultrasonic motor was proposed.The structure of the motor is rather simple and different from the conventional traveling wave ultra.sonic motors.Its production processes are very convenient.It is composed of a stator constituted with a ring and a bar shaped transducer and two cone shaped rotors.The rotors were pressed on inner surface of the ring by means of a pre-pressure system.The bar shaped transducer has a sandwich-like configuration,where two sets of piezoelectric element are bolted.One set excites a longitudinal vibration of the bar,and the other set excites a flexural vibration of the bar.The ring's traveling wave excited with the longitudinal vibration and the bending vibration of the bar transducer was simulated with FEM (finite element method).The prototype of the motor was made and investigated experimentally for its performance.Its maximum torque and ro