Advanced Materials Research Vol. 528

Abstract: Micro interaction forces of lubricity surface of silicon and mica were studied using atomic force microscopy (AFM). From different scanning angle and bisection distance of the AFM, a new method of measuring micro static friction of lubricity surface materials was investigated. Results show that the micro coefficients of static and sliding friction of mica are less than the silicon, but the adhesive force is bigger. The mechanism of friction force of the two lubricity materials was discussed.

Abstract: Na-bentonite(NB)/poly(2-acrylamido-2-methylpropanesulfonicacid)(AMPS) composite were prepared as an adsorbent for the removal of Pb (Ⅱ) from aqueous solutions. Pb (II) adsorption on the composite is a fast process and follows well the pseudo-second-order kinetics. The FTIR spectra indicate NB and poly(AMPS) are simultaneously operating, and chelation should be the dominating adsorption mechanism.

Abstract: Capsaicin exhibits the analgesic and anti-inflammatory activities, therefore it is interesting to apply this natural active compound for periodontitis treatment by local drug delivery system such as intra-canal route. Capsaicin in-situ forming gels were prepared in this research work. The viscosity, gel forming property and capsaicin release were evaluated. 30%W/W eudragit RS 30D in N-methylpyrrolidone (NMP) employed as gel base was physicaly stable after sterilization with autoclaving and exhibited the in-situ forming gel property. This gel base was still clear when capsaicin was less than 0.0094 %w/w. When the system contacted with phosphate buffer pH 6.8 the turbid gel was appeared rapidly at the interface. Viscosity of system depended on the amount of eudragit RS 30D. The rheology of systems was newtonian flow and amount of capsaicin tincture did not affect the rheological behavior. The release rate and amount of capsaicin release form gels were lower than those of capsaicin solution. The sustainable release of capsaicin could be obtained from the developed in-situ forming gel.

Abstract: The silk fibroin/sodium alginate scaffolds were prepared using lyophilization method. And then, the blend scaffolds were treated with calcium ions. The morphology of the blend scaffolds exhibited a thin layer structure before calcium ions treatment, and much more rod-like structure appeared at the layer surface with adding the increase content of sodium alginate in the blend scaffolds. After calcium ions treatment, much more rod-like structure disappeared after adding 30% sodium alginate or more in the blend scaffolds. Wide angle X-ray diffraction and Fourier transform infrared analysis results confirmed the crystal structure of silk fibroin was not influenced by adding the different content of sodium alginate, exhibiting the silk I and silk II structure co-existed in the blend scaffolds. And the same time, the average mass loss value of the blend scaffolds was higher than the pure silk fibroin scaffold, reaching 9.884%, 11.2%, and 8.626%, respectively, when the blend scaffolds contained 10%, 30%, and 50% sodium alginate, respectively. Thus, the silk fibroin/sodium alginate scaffolds should be a useful biomaterial applicable for a wide range of tissue engineering.

Abstract: Three-year-old seedlings of loblolly pine (Pinus taede L.) were selected as materials in this article. The seedlings were planted in spring and divided into five groups, then were artificially inclined at the angles of 0°, 15°, 30°, 45° and 60° from the vertical. The characteristics of compression wood tracheid were observed and recorded, and their variation patterns were analyzed. The following conclusions were drawn: 1) with the increase of the inclined angle, the wall thickness of tracheid increased and the outline of the tracheid became round, the intertracheidular spaces were obvious and increased gradually in all sections derived from the inclined seedlings. The typical characteristics of compression wood were obvious when the inclined angle was bigger than 30°; 2) with the increase of the inclined angle, the tracheid length decreased firstly and then fluctuated, the minimum value reached at 30°; the tracheid width decreased firstly and then increased, the minimum value reached at 45°; the double wall thickness increased firstly and then decreased, the maximum value reached at 45°. 3) In the seedlings studied, the critical angle of inclination was about 30° or 45° from the vertical.

Abstract: We reported the preparation of cubic (α-) and hexagonal (β-) NaYF₄ particles in high boiling organic solvents 1-octadecene (ODE) and oleic acid (OA), through a thermal decomposition synthetic route. The as-prepared products were characterized by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), photoluminescence (PL) spectra. By tuning the reaction temperature and time, we could manipulate the morphology, size, and crystal phase of the products. It was found that the α→β phase transition was favored by high reaction temperature and long reaction time. Highly uniform β-NaYF₄ hexagonal submicroplates were obtained from α-NaYF4 nanoparticles by prolonging the reaction time. The Yb³⁺-Tm³⁺ co-doped β-NaYF₄ hexagonal submicroplates showed s_{Subscript text}trong blue _{Subscript text}and weak red upconversion luminescence under 980nm laser diode excitation. In addition, the dependence of the UC emission intensities upon pump power was investigated.

Abstract: The CaCu3Ti4O12 and Zr-doped polycrystalline CaCu3Zr0.05Ti3.95O12 were prepared via sol-gel method. Comprehensive characterization including X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) equipped with Energy-dispersive X-ray spectroscopy (EDX) were employed to characterize the microstructure, morphology and composition. The dielectric properties of the CCTO based ceramics were studied using impedance analyzer. The results show that replacement of Zr in the Ti- site can achieve the effect of regulation of the dielectric properties.

Abstract: Spinel-type metal compound [LiMnTi0.25O3], was prepared by a solid state reaction crystallization method. LiMnTi0.25O3 can be used to separate Li+ in the aqueous solution. The results showed that the Li+ extraction/insertion be progressed mainly by an ion-exchange mechanism. The acid treated samples had an ion exchange capacity of 4.0mmol/g for Li+

Abstract: The anodic polarization curves of 2205 duplex stainless steel with various RE contents in 3.5% NaCl neutral solutions have been measured by electrochemical methods, The effect of rare earth on pitting corrosion resistance of 2205 duplex stainless steel has been studied by the metallographic examination. The results show that RE can effectively depress pitting corrosion, while the irregular inclusions of Al2O3, sulfide in the shape of clump are transformed into tiny dispersive round or oval RE inclusions, and it plays a good role in pitting resistance.

Abstract: The mechanical process of single-crystal aluminium thin films under uniaxial tensile strain was simulated with molecular dynamics method at different temperature. The stress–strain curve and potential energy–strain curve of thin aluminium film under uniaxial tensile deformation were obtained by molecular dynamics simulations. With the changes of sample temperatures in uniaxial extension, the variation characteristics of stress–strain curves are alike at the elastic stage and different at the plastic one below and above 370 K, respectively. From the stress–strain curves, we gained the first local maximum stress-temperature curve and the strain at the first local maximum stress-temperature curve, and found that the strange temperature dependence of first local maximum stress: when the temperature is above 370 K, the stress goes down quickly with temperature, and when below 370 K, it descends slowly. With increasing temperature, the difference between two strain values corresponding to two maximal potential energies changes slowly below and above 370K but it goes up quickly about 370K. By these dependences, we have identified the critical temperature （370K） for the transition of plastic flow mechanism.