Advanced Materials Research Vols. 393-395

Abstract: Phosphors of SrAl2O4:Eu2+, Dy3+ were encapsulated with polyethylene plastic film by a physical technology. Water resistance measurements, Fourier transform infrared spectroscopy (FT-IR), thermogravimetric (TG) analysis, and photoluminescence (PL) spectrophotometry were used to characterize the phosphors Results showed that the encapsulated layer was a thin film with an encapsulation amount of 4.0 wt%, and encapsulation can effectively improve the water-resistance for the phosphor without any destroy of crystal structure of phosphors.

Abstract: Paper has been removed due to copyright issues

Abstract: The preparation of rubber-based composite from agricultural by-product is the main trend to upgrade the performance of rubber and reduce the cost. In this work, the rice husk ash/natural rubber (RHA/NR) composites were prepared by latex mixing process using the RHA modified with rare earth coupling agent. The mechanical properties, dynamic mechanical properties, thermal stability and morphology of RHA/NR composites were analyzed by universal testing machine, dynamic mechanical analyzer, thermo gravimetric analyzer and scanning electron microscope. The results indicate that previous modification of RHA with rare earth coupling agent can improve the dispersion of RHA in NR matrix significantly and increase the interaction between RHA particles and NR matrix and thus upgrade the mechanical properties and anti-oxidative behaviors of RHA/NR composite. The RHA/NR composite of highest mechanical properties and anti-oxidative behaviors can be obtained with a RHA loading of 4 per hundred rubber.

Abstract: This paper studied factors influencing AU detection results on different damage specimens, including simulation frequency, transducer modes and transducer location. Correlation between acousto-ultrasonic parameters (AUP1, AUP2) and impact damage severity in composite was investigated. The results showed that as damage severity increased, AUP1 and AUP2 of three different transducers decreased. Applying low frequency transducer, the variation of AUP1 may indicate a more rapid detection prospect. In addition, applying S1-transducer and WD-transducer, AUP2 was more effective for the early damage detection. Varying transducer’s location, S1-transducer applying 500khz simulation frequency presented a valuable results.

Abstract: The S-N curves of medium carbon steel(MCS) are determined by the ultrasonic symmetric bending fatigue system (20 KHz). The results show that two S-N curves of MCS display the characteristic of “continually decreasing type” up to 109 cycles and exhibit no traditional horizontal plateau beyond 106 cycles. When the fatigue cycles are over 109, fatigue failure do occurs. By comparison of the two curves of 2mm thick and 5mm thick MCS, the results show that in the high-cycle stage(107cycles), size effect has no significant impact on fatigue Properties. This can also be explained by the theory of crack initiation, in high cycle stage, fatigue crack initiation exists in the sample surface, and in ultra-high-cycle stage, fatigue crack initiation exists in internal initiation.

Abstract: The modified dislocation creep model and the power law breakdown creep model were proposed to be used in the indentation creep deformation analyses for single crystal MgO at low temperature varying from 293K to 873K. A FE indentation creep modeling procedure was proposed and implemented. The activation energy and the shear flow stress for low temperature creep in single crystal MgO were predicted based on the analytical indentation creep analyses.

Abstract: Based on the density functional method, the electronic structures and the optical properties for Al1-xLaxN(x=0, 0.0625, 0.125, 0.1875) are comparatively investigated in detail. The calculation results indicate that La substitution of the Al sites induces effective reduction of the band gap of AlN, and the band gap being continuously reduced when increasing La doping level. With the increase of La concentration, both the imaginary part of dielectric function and the absorption spectrum show red-shift corresponding to the change of band gaps. Moreover, additional absorption peaks are observed above the absorption edge in the high-energy range which widens the absorption region.

Abstract: We researched the effect of single zinc or oxygen vacancy on the electronic and optical properties of V-doped ZnO. All calculations were performed by CASTEP in materials studio software. Total energy showed that an oxygen vacancy inclined to stay at the position far from vanadium (V). A zinc vacancy preferred to localize at the position near V. The V atom substitution for zinc (Zn) introduced spin-polarization at Fermi-level. Vanadium made electronic density of states moved to lower energy. Vanadium doping broadened the density of states peaks of pure ZnO. An oxygen or Zn vacancy also broadened the density of states peaks of V-doped ZnO. The V doping introduced optical properties at lower energy. An oxygen vacancy improved lower-energy optical properties much. Our calculation provided a reference for the preparation and applications of V-doped ZnO in optical fields.

Abstract: It’s well known that curcumin is practically insoluble in water. Therefore, to improve the drug dissolution rate, fusion approach was employed to prepare curcumin solid dispersions (SDs) in the carrier Pluronic F68 with three different drug loads. The dissolution rate of curcumin from the SDs was measured at simulated gastric fluid. The concentration of the dissolved drug in the medium was determined by HPLC. The dissolution rates of the formulations were dependent on the drug loading in SDs. 92.2% CUR was dissolved in 10 min from the SDs with 8.97% drug load, whereas the amounts of drug released were 65.8% and 84.2% within 120 min from the SDs with 18.9% and 29.0% drug loads, respectively. The Fourier transform infrared spectra indicated hydrogen bond between the drug and carrier. Furthermore, their physicochemical properties were well investigated using differential scanning calorimetry and X-ray diffraction. In the dispersions containing 8.97% CUR, the drug was in the molecular state. At a composition of approximately 18.9%, CUR was dispersed as micro-fine crystals. These interesting results indicate that the physical states of the drug in the carrier, which are governed by the drug loading, can affect the dissolution rate improvement.

Abstract: To improve the electronic property of transistor, especially in increasing cutoff frequency, studies were taking in looking for high electron mobility material. IBM et.al companies have paid a serious attention on graphene in brand new Carbon transistor, for it play a ultramundane good electric property in working state[1], the novel graphene channel based fast-speed FET helped A. K. Geim and K. S. Novoselov won the Noble Physics Prize in 2010.