Advanced Materials Research Vols. 1061-1062

Abstract: The new method for synthesis of Benzene-d₆ was discovered. In this process, [Cp*PMe₃IrH₃][OTf] was used as the catalyst at H/D exchange reaction between benzene and deuterium oxide. The prepared method was in an overall yield of 20% and chemical purity of 99.7%. The product contained stable isotopes at 98% enrichment. The MS spectra, ¹³C NMR, IR between benzene and benzene-d₆ were discussed.

Abstract: Novel D-A type conjugated organic molecules composed of central carbazole and phenothiazine units and aldehyde terminal groups have been designed and constructed. Optical properties of the resulting compounds were examined by the mean of UV-vis and fluorescence spectroscopies. The fluorescence spectra of the molecule C2 based on central carbazole unit show strong emission peaks in the blue light regions, which are expected to be promising light-emitting materials for organic light-emitting diodes applications.

Abstract: The band structures were given by study on the chemisorptions of atom on the Si (100) surface. From these curves, the pseudogap, forbidden bandwidth, the trend of Fermi level in the graphics at the Fermi level were analyzed and compared for different elements absorption. The conclusion is that the electrical conductivity of Cu, Na is the best, followed by C, the last is the Si.

Abstract: The density of states was given for the chemisorptions of atom on the Si (111) surface. From these curves, the characteristics, such as the pseudogap, forbidden bandwidth, energy curve, the trend of Fermi level in the graphics and the density of states at the Fermi level and so on, were analyzed and compared to for different elements absorption on the Si (111) surface. The density of states for chemisorptions is different for the different elements.

Abstract: Physical and chemical properties were measured to study quality of 5 strawberry cultivars, which were fruit weight, firmness, vitamin C, total sugar, total anthocyanin, total phenols, pH, total soluble solid, titratable acid, crude protein and juice yield. The result showed that PC1 explained 54.519% of the total variance in the data set, PC2 explained 28.184% and PC3 explained 9.252%. Accumulative variance contribution of these three main compositions extracted by principal component analysis was 91.954%. Eleven properties could reduce to three main components, and five strawberry cultivars were distinguished based on PC scores.

Abstract: Cerium hydroxide was prepared with Cerium carbonate by green synthesis. The products were characterized by several analytical methods. Fourier transform infrared spectroscopy was used to determine whether the product was Cerium hydroxide. X-ray technique was used to study the phase composition. DSC-TG was used to study its thermal stability. X-ray fluorescence spectrometer was used to study its content and impurity. The results show that the prepared product is Cerium hydroxide, and made of Cerium hydroxide mainly, its content of impurity is 0.94%, and there are traces of water in the powder. It is a kind of amorphous structure, has good thermal stability when the temperature was exceeded 480°C.

Abstract: Phosphotungstic acid cerium [CePW₁₂O₄₀] was prepared with phosphotungstic acid and hydrate cerium nitrate by precipitation method. The Fourier transform infrared spectrometer, X-ray diffractometer, X-ray fluorescence spectrometer and thermal gravimetric analysis were used to characterize product, The UV-VIS spectrophotometer was used to measure its absorption capacity. The results showed that the prepared product is CePW₁₂O₄₀, it has good crystal and good thermal stability, its purity reaches 99.55%, there is good UV absorption property between 200nm and 260nm..

Abstract: we report reproducible resistive switching performance and relevant physical mechanism of Pt/La_0.7Sr_0.3MnO₃/Nb_0.05Bi_0.95FeO₃/Nb:SrTiO₃ ferroelectric heterostructure which was fabricated by pulsed laser deposition. This device exhibits a nonvolatile resistive switching with a resistance ratio of up to 60 under 2V/-3V pulse voltages at room temperature. Low voltage readout, reliable resistance switching reproducibility and good time retention, indicating promise for non-destructive readout nonvolatile memories. In this metal/p-semiconductor/ferroelectric/n-semiconductor heterostructure, the mechanism of resistive switching behavior would be attributed to the ferroelectric polarization enhanced field-induced charge redistribution at the semiconductor/ferroelectric interface, resulting in the modulation of the interface barrier height. Keywords: Resistive switching, Ferroelectric resistive switching, Ferroelectric field effect.

Abstract: The high-performance solid propellants play very important role in defense industry, which required highly energetic binders with good mechanical properties. In order to get the activation parameters for energetic binders, In-Situ FT-IR spectroscopic technique is used to study the chemical kinetics of glycidyl azide polymer (GAP) and hydroxyl terminated poly butadiene (HTPB) with isophorone diisocyanate (IPDI) at various temperatures. The reaction was followed by monitoring the change in intensity of the absorption band of NCO stretching at 2257cm^-1 and CO stretching at 1731cm^-1. The polyurethane reaction has been found to be second order and the rate constant seems to be different between GAP/IPDI and HTPB/IPDI due to reactivity difference of OH groups. Dibutyl tin dilurate (DBTDL) was used as curing catalyst. By using Arrhenius and Eyring equations, the activation parameters were obtained at different temperatures (60, 70, 80 and 90°C). The apparent activation energy for the two systems GAP/IPDI and HTPB/IPDI were found to be 63.51 kJ mol^-1 and 41.06 kJ mol^-1 while the enthalpy and entropy of activation were found to be 62.35 kJ mol^-1 and-36.24 kJ.mol^-1K^-1, 39.08 J mol^-1 and-98.84 J mol^-1K^-1 respectively.Key words: In-Situ FT-IR; glycidyl azide polymer (GAP); hydroxyl terminated poly butadiene (HTPB); chemical kinetics; polyurethane; dibutyl tin dilurate (DBTDL).

Abstract: In this study, we converted high silicon fly ashes (FA) to zeolites using a two stages conversion process: alkaline fusion followed by hydrothermal crystallization. The orthogonal experimental method was applied to design the experimental variables of alkaline fusing and hydrothermal crystallizing procedure. Alkaline fusion prior to hydrothermal synthesis was applied to collapse the FA crystalline phases and release Si content. Different from most of the research, the mixtures of NaOH and Na₂CO₃ were used to increase the fusion temperature in order to remove the residue carbon simultaneously. Acid solubility was used to evaluate the efficiency of alkaline fusion. Then the optimized alkali-fused FA was resolved in the NaOH solutions and the experiment conditions were designed by the orthogonal experimental method. XRD and SEM were employed to characterize the crystalline phases and microimages of the raw FA and the treated FA. Adsorption process of methylene blue was applied to simulate the adsorption ability of the fly ash zeolites. Finally, the optimized conditions of alkaline fusion and hydrothermal treatment were concluded.