28 February 2015, Volume 46 Issue 04
    

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    研究 开发
  • ;
    . 2015, 46(04): 1-0.
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    Based on the initial structural model referred to experimental data, geopolymeric gel structural model was established by molecular dynamic simulation technique according to structural characterization of N-A-S-H gel.In this model, Na atom, H2O molecule, and Si2AlO10 were chosen as the main compositions of the primary unit. Simulation and optimization of operation was conducted in term ofthe direction of system movement. The accuracy of the proposed model has been verified and confirmed by the comparison of simulations and experimental data including computed radial distribution function (PDF), X-ray diffraction (XRD) and mechanical properties.The results show that simulationsresults are in accordance with the experimental data.It not only revealsthe usability of the proposed model but also makes it possible to study onthegeopolymericN-A-S-H gelsystem deeply.
  • Wang-Lan ;;
    . 2015, 46(04): 2-0.
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    To evaluate the temperature susceptibility of different polymer modified asphalt( SBS modified asphalt(SMA), rubber powder modified asphalt (RPMA), composite modified asphalt (CMA)) before and after short-term aging, the dynamic shear rheometer test was conducted for the samples of them before and after aging, then the aging temperature scanning data were taken for linear regression of viscosity - temperature curve using different algorithms under the different temperature scales, according to the result of regression ,the viscosity-temperature exponent —VTS can be obtained. The most suitable scale and algorithm were analyzed from the view of linear correlation coefficient; and the temperature susceptibility of different polymer modified asphalt were evaluated using VTS under the different temperature scales. Next, the reason why different polymer modified asphalt have different temperature susceptibilities was analyzed from the microstructure of asphalt using scanning electron microscopy (sem) test. Results showed that: the VTS fitted under the kelvin scale and Rankine scale can evaluate the temperature susceptibility of different modified asphalt more appropriate; the influence of the changes of components and wax is the biggest of all, followed by the influence of colloid structure and molecular weight ;short-term aging decreases the temperature susceptibility of modified asphalt, rubber powder modified asphalt has the lowest temperature susceptibility before and after aging.
  • ;;;Bing-Jie LIU
    . 2015, 46(04): 3-0.
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    Cross-linked xanthated chitosan resin was prepared mainly by the method of inverse suspension cross-linking using glutaraldehyde as cross-linking agent and carbon disulfide as modification agent. The addition of thiol group on cross-linked chitosan enhanced its interaction with patulin in aqueous solution and increased the adsorption ability of CXCR for patulin. The adsorption mechanism of CXCR for patulin was characterized by Fourier transform infrared spectroscopy. The influence of various parameters on the adsorption capacity of CXCR for patulin was investigated. The results showed that the adsorption capacity was 6.53 mg/g when 8 mg/L patulin was adsorbed at pH 4, 25 ℃ for 16 h by adding 1 g/L CXCR. The adsorption process was found to follow pseudo-second order kinetics model. The experimental data fitted Freundlich adsorption isotherm model. It indicated that CXCR is a very promising biosorbent for adsorption of patulin from aqueous solutions.
  • Lu Xu Dong
    . 2015, 46(04): 4-0.
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    The oxidation behaviour of Cr5.0 Co8.0 Mo0.9 W5.5 Ta7.4 Al6.0 Re4.2 superalloy at 900 ℃ and 1000 ℃ in air has been investigated by means of measuring the kinetics curves of the oxidation and analysis method of TGA, XRD and SEM/EDAX. Results show that the oxidation initial oxidation rate is rapid, with the oxidation time, the increasing of oxidation weight overall tends to be smooth, but the oxidation kinetics curve for superalloy later has a wavy change and obviously for the higher oxidation temperature. The oxidation film are consist of three layers at 900℃.The outer layer is mainly composed of NiO, Ni2Cr2O4, Ni2CoO4, CrTaO4 and continuous middle layer and disconnected inner layer of Al2O3. The phase CrTaO4 decreases the diffusion rate of Al. As a result, a continuous oxide layer of Al2O3 is formed in the middle layer to restrain the growth of oxide film and decrease the oxidation rate. The oxidation film are consist of two layers at 1000℃.The outer layer is mainly composed of NiO, Ni2Cr2O4, Ni2CoO4, CrTaO4, and disconnected inner layer of Al2O3.The internal oxide(Al2O3) and internal nitride(AlN) precipitates formed inside the superalloy after exposure for 300h during oxidation at 900 ℃ and 1000 ℃; the internal oxidation zone forms on the near-surface area of the superalloy, internal nitridation zone forms below the internal oxidation zone inside the superalloy; with the increasing of temperature the internal oxidation zone and internal nitridation zone are wider, simultaneity the size of internal nitride and internal oxide increase.
  • . 2015, 46(04): 5-0.
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    We used density functional theory (DFT) with the MPW3PBE functional to optimize the firefly enol-oxyluciferin with the substitution of methyl, methoxy, cyano, fluorine, amino and nitro groups. Based on the optimized molecular structures, the ionization potentials (IP), electron affinities (EA), hole extraction potentials (HEP), electron extraction potentials (EEP), as well as hole and electron reorganization energy (λ) were calculated to investigate the hole and charge transport properties. The electronic absorption spectra, the lowest excited singlet state (S1) and the fluorescence spectra of firefly enol-oxyluciferin derivatives were calculated by the time dependent density functional theory (TDDFT) TD MPW3PBE/6-31+G(d) method. The results showed that E-CN is an excellent candidate for the bifunctional OLED materials. It can be used as charge-transport and light emitting materials simultaneously. E-NO2, E-F and E-OCH3 can be used as electron transport materials. And E-NH2 can be used as hole-transport materials.
  • Xu Hong Yao;
    . 2015, 46(04): 6-0.
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    Two types of triazine reactive dyes were designed and synthesized. Their structures and fluorescent probe properties for detecting Zn2+ were characterized and evaluated by IR, 1HNMR spectra, UV-visible absorption spectra and fluorescence spectra, respectively. The influence of molecular structure on fluorescent probe properties of reactive dyes was investigated. The probe mechanism of the reactive dyes for Zn2+was studied by experiments and theoretical simulation, respectively. A good linear relationship between the fluorescence intensity of triazine reactive dyes and the concentrations of Zn2+ was exhibited with a wide concentrations range of 1-10μM、0.1-5μM as well as the detection limit of 3μM、1μM.
  • ;;
    . 2015, 46(04): 7-0.
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    The precursors of Y-type hexaferrite (Ba2Co0.4Zn1.0Cu0.6Fe12O22) were obtained by chemical co-precipitation method, and the effects of co-precipitation reaction time on particle size, surface topography, crystal structure and magnetic properties of the powders and the sintering samples were investigated via laser particle size analyzer (LPS), scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and E4991A impedance analyzer. The results showed that the precursor obtained at 90 h (co-precipitation reaction time) has a relatively narrow grain size distribution (1 μm on average). The well-defined Y-type hexagonal ferrite was formed after sintered at 900 °C. The sintered sample shows a relative density above 95%, an initial permeability (μi) of 3.7, a quality factor (Q) of 5.8 in the 1 GHz frequency, a resonance frequency above 2.5 GHz and a cutoff frequency around 3 GHz.
  • . 2015, 46(04): 8-0.
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    Abstract: Aluminum nano-particle films are successfully deposited on mechanically polished monocrystal silicon substrates by DC magnetron sputtering, where the highly pure aluminum(99.99%) was used as target with the argon(99.999%) as sputtering gas. The crystal structure, thickness, surface morphology and electrical resistivity were studied by X-ray diffraction (XRD), optical thickness measuring, scanning electron microscopy (SEM) and four point probes meter, respectively. The XRD pattern showed that these Al nano-particle films had preferred orientation of Al(111) with fcc polycrystal structure. When sputtering power increased from 30W to 300W, The deposition rate increased from 3.03nm/min to 20.03nm/min, while decreased from 2.95nm/min to 1.66nm/min when the sputtering pressure increased from 1Pa to 3Pa. SEM images of surface morphology showed that the Al nano-particle films sputtered at 150W and 1Pa were perfect. With the sputtering power increased from 80W to 160W, the electrical resistivity decreased from 4.0 × 10-7 Ω˙m to 1.9 × 10-7Ω˙m, while increased from 1.9 × 10-7 Ω˙m to 7.1 × 10-7 Ω˙m with the sputtering pressure increasing from 1Pa to 3Pa.
  • ;
    . 2015, 46(04): 9-0.
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    Ti-doped WO3 nanocrystals with different Ti-doped concentrations are synthesized by hydrothermal method, and annealed at 350℃ for 1 h. Morphology and structure of these materials have been characterized by the scanning electron microscopy and X-ray diffraction instrument, the gas-sensing properties to nitrogen dioxide at 200℃ of film sensors made of the unannealed and annealed materials are studied. The results show that Ti-doped can effectively inhibit the growth of nanocrystals, reduce the size of nanocrystals; the crystalline phase of these materials have changed after annealed, the size of nanocrystals is further reduced, the dispersion of nanocrystals becomes better. The tests of the film sensors show that the amount of Ti-doped and annealing can improve the sensitivity of sensors to NO2, the film sensor made of the annealed Ti-doped for 2% has a maximum sensitivity of 15.38 and a good reproducibility and stability, the response and recovery time is 2.2min and 1.5min, respectively.
  • . 2015, 46(04): 10-0.
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    Graphene oxide (GO) nanophase dispersion was prepared by Hummers method followed ultrasonication. The effects of GO on fluidity of cement pastes and microstructure of hardened cement paste were studied. The microstructure of GO and hardened cement paste were characterized by FTIR, AFM, XRD and SEM. The tested results showed that the fluidity of cement paste with GO would reduce. And the study also found a 0.01% increase in the dosage of GO should increase 0.02% of polycarboxylate superplasticizer (PCs) in order to keep the fluidity more than 200 mm within 3 hours. Meanwhile, the results also showed that the microstructure of hardened cement hydrate have changed obviously with the addition of GO. When GO/PCs dosage was 0.01%/0.24% ~ 0.03%/0.28%, there are lots of flower-like micro-crystals with distribution evenly in the hardened cement paste at hydration age of 7 days. When GO/PCs dosage was 0.05%/0.32% ~ 0.07%/0.36%, there are many lamellae shaped crystals in the hardened cement paste at 7 days. And the hardened cement paste showed dense trend with hydration age extended to 28 days. The results suggested that GO can ragulate the microstructure of cement hydration products and have excellent reinforcing and toughening effects, which has a significance for the improvement of the strength and toughness of cement based composites
  • Hui Yang;Xu-Feng DONG min qi ;
    . 2015, 46(04): 11-0.
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    Flower-like microparticles were synthesized by a simple solvothermal method. The morphology and structure of the particles were characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM) , X-ray diffraction(XRD) and infrared spectroscopy(FT-IR). The results showed that the flower-like particles are titanium glycerolate phase, and present secondary thorn structure on their surface. The diameter of flower-like particles ranges from 2μm to 3μm. Two electrorheological(ER) fluids were fabricated by dispersing the flower-like particles and smooth spherical particles, the composition of which was TiO2, in silicone oil. The electrorheological behavior and sedimentation stability was tested. The results indicated that at the same electric field levels, the flower-like particles-based ER fluid presents higher yield stress and lower current density than the smooth spherical particles-based one. Furthermore, after 12 days’ setting without disturb, the sedimentation stability of the flower-like particles-based ER fluid was much better than that of the smooth spherical particles-based material. The specific morphology of the flower-like particles may be the main reason for the significant ER effect and good sedimentation stability.
  • . 2015, 46(04): 12-0.
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    Micro-sheet polypyrrole (PPy) / graphene oxide (GO)composites were prepared by in situ polymerization at ultra-low temperature (-10℃). On the basis of the structural characterization of the composites by Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) tests, the electrochemical performances of the composites were investigated by cyclic voltammetry (CV), galvostatic charge-discharge (GC) and electrochemical impedance technology (EIS). The FTIR analysis indicated the presence of interactions between GO and PPy in the composites. SEM results showed that the composites provided a submicron-sheet structure. The composites showed a better capacitive behavior than both GO and PPy. The composites had a higher specific capacitance of 319F/g (current density=1A/g) than either composite constituent (10F/g for GO and 167F/g for PPy). The composites could be used as potential electrode material for supercapacitors.
  • ;Jun DU;;;;
    . 2015, 46(04): 13-0.
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    CeO2/epoxy composite was prepared by solution process with CeO2 powder modified by KH560 coupling agent. The impact of coupling agent on microstructure of composites was investigated by Raman, UV-vis DRS and FESEM. The electrochemical corrosion behavior of epoxy resin treated CeO2/epoxy composite and untreated CeO2/epoxy composite were measured by CHI660D electrochemical workstation respectively. It showed that the coupling agent improved the interaction between CeO2 and epoxy. Both the fraction of CeO2 and KH560 had effective on adhesive force and corrosion resistance. The adhesive force of the composite with treated CeO2 on galvanized steel was one grade, the contact angle of water against it to be 82.5°and its electrochemical impedance was 109 Ω?cm2 at the beginning of immersion time and about 107 Ω?cm2 in the later stage. It was higher than that with untreated CeO2 and epoxy resin. The adhesive force and protective performance of the untreated CeO2/epoxy composite was better than that of the epoxy resin. The treated CeO2/epoxy composite was the best among the three materials.
  • ;shengzhong Kou
    . 2015, 46(04): 15-0.
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    (Fe0.46Co0.36Ni0.04Zr0.14)100-xTax(x=0,4,8,12) amorphous alloy composites rods were prepared by copper mold suction casting.Influences of Ta addition on magnetic properties and mechanical properties of (Fe0.46Co0.36Ni0.04Zr0.14)100-xTax amorphous alloy composites were investigated by the means of X-ray diffraction(XRD),Selected Area Electron Diffraction(SAED),Vibrating Sample Magnetometer(VSM),the compute controlled electronic mechanical testing system and Scanning Electron Microscope(SEM).The results show that some crystal phase Co2Zr,Co2Ta0.5Zr0.5 were separated constantly out with the increase of Ta content,coercivity Hc was decreasing and saturation magnetization Ms,compressive strength σbc,elastic strain εe were increasing firstly,then decreasing with the increase of Ta content. Ms,σbc,εe reached the maximum value which are 137.70 Am2kg-1,1814 MPa and 4.583% when x=4.It shows that the suitable Ta content can obviously improve the magnetic and mechanical properties of (Fe0.46Co0.36Ni0.04Zr0.14)100-xTax amorphous alloy.
  • ;Yi LIU;;;;
    . 2015, 46(04): 16-0.
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    Sillenite type Bi25FeO40 has been used as the research subjects in this paper. Various Morphologies of Bi25FeO40 nano-materials have been successfully synthesized by hydrothermal method on the titanium substrate. The effect of processing parameters such as reaction temperature(160~200℃), mineralizer and stoichiometry was investigated by XRD and FE-SEM. Bi25FeO40 are found to have a good visible response ability from 400 to 600 nm through UV-Vis diffuse reflectance spectroscopy. The photo-electrochemical properties were measured by three electrodes measurements. The sample of nanorods morphology responded rapidly when irradiation.
  • saijia huang;jianbo yang;Xing-Ao LI
    . 2015, 46(04): 17-0.
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    V-doped Cu3N films were prepared successfully by magnetron sputtering under the experiment condition. XRD shows that the Cu3N film growth prefers direction by changing from (111) to (100) direction with increasing the content of V. SEM shows that the grains’ shape of Cu3N crystals has been changed by inserting V atoms into the film. Moreover, the optical absorption, electric conduction and mechanical property of the Cu3N films have been better by doping V to the films.
  • . 2015, 46(04): 18-0.
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    Abstract: Based on the Fe-Si-B-P amorphous alloy system, we successfully developed the amorphous alloys with large GFA and excellent magnetic properties by micro-alloying Mo element and increasing Fe content. We found that micro addition of Mo can effectively increase the glass forming ability. With only 1% addition of Mo, the Fe limitation to form a single amorphous phase is increased up to 84% leading to a high Bs up to 1.63T. Additionally, the as designed Fe80Si4.75B9.5P4.75Mo1 alloy can form a glassy rod with a Dcr of 1mm exhibiting a high Bs of 1.54T and low Hc of 1.9A/m. Owning to the excellent magnetic properties such as low Hc of 1.9-5.1A/m and higher Bs than traditional Fe-Si-B amorphous alloys, the present alloy system is believed to be promising soft magnetic materials for the application in the future.
  • 综述 进展
  • Chen-Tao JI;
    . 2015, 46(04): 19-0.
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    Ceramic silicone rubber fire-resisting material has been proved to be a new fireproof composite. The new type of flame retardant material consists of silicone rubber as the base polymer, to which inorganic clay mineraloid powder filler, dispersant agent and other additives are added. The behaviors of ceramifiable composite are similar with common polymer in normal temperature while in high temperature or in flame it converts into a rigid ceramic protective layer. This protective layer plays an important role in cutting off the flame and temperature, thus ensures normal transmission of power and message under fire conditions. The paper systematically introduces pyrolysis mechanism of silicone rubber matrix, fire-resisting mechanism of ceramifiable composites, functions of inorganic fillers like mica, calcium carbonate, aluminum hydroxide and magnesium hydroxide in the ceramic process and their influence on the ceramifiable silicone rubber composite, and introduces its fabrication technologies. On this basis, the paper gives a outlook of the ceramifiable silicone composite.
  • 工艺 技术
  • . 2015, 46(04): 20-0.
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    The impact resistance of concrete was measured using self-designed U-shape concrete specimens and a newly designed drop weight impact machine. According to the expectation estimation of mean rank method, the concepts of order statistics and rank are introduced to estimate the values of the function of cumulative failure probability F(N) and survival probability R(N). A series of drop-weight tests were carried out for U-shape concrete specimens with four different quality level of drop hammer, and the distribution regularity of the impact life N was analyzed by the theory of double parameters Weibull distribution and linear regression theory. The research results show that the impact life N of U-shape concrete can be modeled well by the theory of Weibull distribution.
  • 综述 进展
  • ;; ;
    . 2015, 46(04): 22-0.
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    As one of a typical perovskite structure. PZT provide a wide flexibility for doping modification. The paper have introduced the current investigation of PZT-doping modification and briefly analyzed the variation of property which affected by equivalent doping, donor doping, acceptor doping and multiple doping respectively The theory of doping modification has been discussed by two aspects: crystal structure and domain structure effected by doping ,which will provide theoretical base of doping.
  • 工艺 技术
  • ; Kong-yin Zhao ;;;
    . 2015, 46(04): 23-0.
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    In this thesis, urea was used as a porogen to prepare calcium alginate (CA) hydrogel filtration membrane. The flux, retention and mechanical properties of the CA filtration membrane were tested. The surface morphology of CA filtration membrane before and after filtrating calcium sulphate was observed by scanning electron microscopy (SEM). Results showed that the stress and strain of the membrane reduced with the increase of urea content. When the concentration of urea was less than 2.5wt.%, the water flux of membrane increased rapidly with the increase of urea content. When the urea was 3.0wt.%, the flux reached 28.7L/m2?h. With the continue increase of the urea amount the flux increased little. When the pressure was fixed at 0.2 MPa, the retention rate of Ca2+ and SO42- for the CA filtration membrane was 83% and 92%, respectively. And the stable flux reached 21.7L/m2?h.
  • Liu-Jun XU;;
    . 2015, 46(04): 24-0.
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    Ytterbium and nitrogen co-doped TiO2 photocatalysts which could degrade methyl blue (MB) under visible light irradiation were prepared by sol-gel method combined with microwave chemical synthesis. Samples were characterized by XRD, XPS, UV-Vis-DRS and PL. The results show that Yb, N co-doped narrowed the band gap and inhibited the recombination of photogenerated electron-hole pairs. The band-gap energy absorption edge shifted to longer wavelength, thus the photocatalytic activity is improved. Results of degradation revealed that the (Yb, N)-TiO2 has shown much more photocatalytic activity than the P25 when the preparation condition is as follows: sintered temperature T=650℃, pH=1.5, m(H2NCONH2)=10g n(Yb):n(Ti)=0.005.
  • . 2015, 46(04): 25-0.
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    Magnetorheological elastomers (MREs) are a class of smart materials whose mechanical properties can be changed under different magnetic field. The modulus of MREs is divided into the modulus under no magnetic field and the modulus induced by the magnetic field. Based on the Periodic Boundary Condition (PBC), a representative volume element (RVE) was proposed to calculate the macroscopic Young's modulus and shear modulus without a magnetic field. By introducing the Maxwell stress tensor, the Young's modulus and shear modulus induced by different magnetic flux induction of MREs were studied. By using the RVE approach it is proved that the Young's modulus induced by the magnetic flux density is negative, while the magnitude of Young's modulus of the whole MREs increases with increasing magnetic flux density. The shear modulus of MREs is positive and the magnitude of shear modulus increases with increasing magnetic flux density. The dipole theory is consistent with the conclusion.
  • Jing-Ying ZHANG
    . 2015, 46(04): 26-0.
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    ABSTRACT Titanium (Ti) and its alloys have been used widely as implants due to their excellent mechanical toughness, strength, corrosion resistance and biocompatibility. However, they exhibit poor osteoinductive properties because of their bioinert character. To improve their bioactivity, numerous techniques have been elaborated to enhance the surface compatibility of implants with bone. Ti and Ti6Al4V are mostly used in the aerospace, marine and biomedical industries, occupied 50% of the titanium market. However, Ti has low strength and undergoes physical abrasion due to oral prophylaxis and other processes in oral cavity. Furthermore, the grey color of Ti can cause aesthetic problems when it is inadequately masked by soft tissue at gingival area. Ti6Al4V began to lose its popularity in the late 1980s after recognition of toxicity arising from in-vivo release of vanadium present in the composition. To overcome these drawbacks, Ti6Al7Nb alloy has been developed specifically for implant applications by substitution of vanadium with niobium. In the present study, the in-vitro biological responses to Ti、Ti6Al4V and Ti6Al7Nb were investigated after modifying their surfaces by sandblasting and acid etching (SLA). The SLA process was sandblasted by Al2O3 particles and acid etched by a mixture of hydrochloric acid and sulfuric acid. After the process, the surfaces of the samples were porous of micro meters. Simulated body fluid (SBF) tests were conducted to compare the biological performance of the samples. The sample surface morphologies were characterized by SEM, Surface crystal structure of the samples was analyzed by using an X- ray diffractometer (XRD). Even though micro structure of the samples exhibited somewhat similar, the deposition of calcium (Ca), and phosphate (P) on the surface of Ti6Al7Nb alloy was faster and greater than that of the Ti and Ti6Al4V, which is significant for implant surface modification.
  • Shuan-Bao GUO;
    . 2015, 46(04): 27-0.
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    The hydrogen-bond acid compound 2,2-bis(4-hydroxyphenyl)-hexafluoropropane (BHPHFP) has been used as a sensing group progressively grafted on the mesoporous-silica KIT-5 via chemical coupling reaction by 3-iodopropyl trimethoxysilane. Furthermore, it is successfully characterized by transmission electron microscopy (TEM), high resolution scanning electron microscopy (HR-SEM), flourier transform infrared (FT-IR), N2 sorption isotherms and thermogravimetry analysis (TGA) curves. Then taking the quartz crystal microbalance sensor (QCM) as platform to form the organophosphorus vapor detection sensor, the QCM sensor obtains a higher sensitivity, repeatability and selectivity to detect the ppb-level concentration of organophosphorus vapor.
  • . 2015, 46(04): 28-0.
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    石墨烯作为一种碳原子所组成的二维蜂窝状结构晶体,具有诸多优异的特性,从而倍受全世界科学工作者的关注。在碳化硅衬底上外延生长石墨烯是实现石墨烯在微电子领域中应用的最有效途径之一。本文利用感应加热的高温CVD设备,先在4H-SiC衬底上外延生长一层2-10微米厚的碳化硅,然后直接再在外延碳化硅上原位外延生长石墨烯。实现外延碳化硅-石墨烯的连续生长,从而减少氢气刻蚀带来的晶格缺陷和表面硅富集严重削减现象,并使低成本制备碳化硅上的石墨烯成为可能。通过拉曼光谱、扫描电子显微镜及X射线光电子能谱等表征,验证了该方法生长的石墨烯具有较好的晶体质量。
  • . 2015, 46(04): 29-0.
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    The evolution of microstructure of concretes utilized under marine environments was studied by microhardness, SEM, XRD, MIP and 29Si MAS NMR. The results showed that concrete under marine environments was apt to dissoluble and expansile erosion as gypsum and ettringite was prone to gatherer in interface transition zone. Concrete that includes slag was significantly less porous and enhanced the mechanical properties of the interface transition zone. However, with the slag content more than 30%, the pore refining effect was less significant and the distribution of pore diameter was polarized, obviously increased the harmless pore and much harm pore, and reduced harmful pore and less harm pore. The [SiO4] tetrahedron of hydration products in addition to the form of Q1, Q2 and Q2 (1Al), also take the form of Q3 and Q4. It means that the resonance frequency of 29Si has been reduced and the chemical shift has a shift to negative.
  • Ya-Kun XIN;
    . 2015, 46(04): 31-0.
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    The polycrystalline silicon thin films with (220) and (400) preferred orientation were prepared respectively on graphite substrate. Two kinds of samples were prepared. First, amorphous silicon thin film was prepared directly on graphite substrate by magnetron sputtering technique, and second, the ZnO transition layer was prepared before the deposition of amorphous silicon thin film. Both kinds of samples were annealed by rapid annealing method. X-ray Diffraction (XRD) measurements show that the silicon thin film seed layers without ZnO transition layer have highly (220) preferred orientation, and the silicon thin film seed layers with ZnO transition layer have highly (400) preferred orientation, after the rapid annealing. Then the polycrystalline silicon films were prepared by convection-assisted chemical vapor deposition (CoCVD) on the polycrystalline silicon thin film seed layers. According to the Scanning Electron Microscope (SEM), XRD, and Raman measurements, the structures of the silicon films deposited by CoCVD succeed to the structures of polycrystalline silicon seed layer. The samples without ZnO transition layer have highly (220) preferred orientation, and the samples with ZnO transition layer have highly (400) preferred orientation. The mechanisms that the Si (220) and Si (400) preferred orientation were analyzed preliminarily