Advanced Materials Research Vols. 455-456

Abstract: π stacking and water-solubility of brilliant blue (BB) are expected to facilitate the hydrazine mediated reduction of graphene oxide (GO) in aqueous environment. Our newly-obtained BB-functionalized reduced graphene oxide (BB-rGO) exhibited excellent solubility and stability in water. The properties of BB-rGO were investigated. The results showed that the BB molecules stacked non-covalently onto the basal plane of rGO by strong π-π interactions while the sulfo groups of BB prevented the rGO from aggregation by electrostatic and steric repulsions, therefore leading to the solubility and stability of BB-rGO in aqueous dispersion.

Abstract: Based on the analysis of glass formation region of Y₂O₃-Al₂O₃-SiO₂ glass system, the glass composition 5Li₂O-18Y₂O₃-29Al₂O₃-48SiO₂ (LYAS) in mol% central in the glass formation region of Y-Al-Si glass system was chosen for present work. The Tm³⁺ and Yb³⁺ were introduced as activators in LYAS glass. The glass samples were prepared by the high-temperature solid-state melting and then the derived YAG glass-ceramic was obtained by heat-treating the precursor glass. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis results indicate that the lattice constant of the obtained glass-ceramic is consistent with the pure YAG phase. The primary crystallite size is calculated to be 46nm and the crystal grains grow with excellent orientation (444) in the internal network. The secondary particle size is estimated to be ~8μm and the large grain size is owing to the particles aggregation. The crystal grains distributed uniformly in the glass matrix, and consistent well with the XRD analysis results.

Abstract: Many attempts are made to obtain the composition of vacuum gas oil (VGO) but the molecular composition of hydrogenated vacuum gas oil (HVGO) has not been studied in detail. HVGO is used as a feed in fluid catalytic cracking (FCC) to produce more environmentally friendly gasoline. This paper reports the presence of linear alkyl cyclohexanes (LACHs) in HVGO. Some LACHs were found in HVGO distillates of boiling point range of 370°C-550°C. Complete molecular composition was analyzed using gas chromatography mass spectrometry (GC-MS). HVGO contains LACHs from C₇ to C₃₂ and n-paraffins from C₅ to C₃₈. Open chain hydrocarbons are the major constituents of all the six samples of HVGO. Aromatic compounds were also identified but their concentration was very low. Sulfur contents were about 0.26% by weight percentage (wt).The present paper focuses on development of method for qualitative and quantitative determination of LACHs in HVGO samples using GC-MS analysis method.

Abstract: A rapid preparation route, microwave-assisted chemical solution method, has been developed for the fabrication of zinc sulfide (ZnS) thin film and powder with shape of microsphere. The as-obtained products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and optical measurement. XRD results indicated that the structures of as-obtained products are wurtzite. The SEM and AFM photographs show that uniform ZnS microsphere with size of less than 1 μm and homogeneous thin film could be obtained from solution under adequate conditions with thiourea as sulfide source. The results show that microwave-assisted chemical solution method is really a time saving method to fabricate the ZnS thin film and nanostructured microspheres.

Abstract: A new method for determination of antioxidants in jet fuels, which is based on the differential pulse voltammetric characteristics of the antioxidant 2,6-ditertbutyl-4-methylphenol in the solution of saturated KOH anhydrous ethyl alcohols, is established. The experimental results have shown that there is a linear relationship between the content of 2,6-ditertbutyl-4-Methyl-phenol in the jet fuel and the differential pulse voltammetry response in the electrolytic solution. It has also been shown that the antioxidant contents can be reliably and simply determined with the help of the standard addition method. The largest relative error of the determination is 6.70 %, the biggest confidence for 5 samples is 1.95 mg/L (n=5, 95% confidence level).

Abstract: This work reported that ultrasound changed the solid-liquid leaching equilibrium of glycyrrhizic acid (GA) from glycyrrhiza uralensis in water. Several critical variables were considered, including temperature, ultrasonic power and frequency. The equilibrium concentration of GA increased by increasing the temperature, while the optimal ultrasonic frequency was affected by the temperature and the ultrasonic power affected the concentration lightly when the power was more than 100W. To investigate the cause that ultrasound changed the solid-liquid leaching equilibrium, a scanning electron microscope was used to observe the solid structure before ultrasound treatment and after that. It was found that ultrasound was able to change the structure of glycyrrhiza uralensis. So a new equilibrium was built and the equilibrium concentration of GA was influenced because the solid structure was transformed by ultrasound.

Abstract: LiCoPO₄ was prepared by a citric acid assisted sol-gel method and exploited as cathode material for lithium ion batteries. TG curve showed the appropriate temperature of the reaction and X-ray diffraction patterns indicated that LiCoPO₄ synthesized at different temperatures was crystallized in an orthorhombic structure. During charge-discharge cycles, LiCoPO₄ presented a plateaus of 4.8V corresponding to Co³⁺/Co²⁺ redox couples, and a discharge capacity of 126.3 mAh/g in the first cycle. The CV curve of LiCoPO₄ showed that Li-ion diffusion in LiCoPO₄ obeyed a different mechanism between charge and discharge processes.

Abstract: Generally, open-framework metal phosphites like phosphates, are synthesized under hydrothermal or solvothermal conditions in the presence of organic amines, which may act as structure-directing agent or template to avoid the formation of dense phase, but few of them has been successfully prepared at room temperature which seems to be difficult to synthesize these compounds. In this work, at room temperature, employing n-propylamine as a template, a three-dimensional zinc phosphite (C₃H₁₀N) ₂·[Zn₃(HPO₃)₄] has been prepared and characterized by single-crystal X-ray diffraction, FTIR, elemental analysis, powder X-ray diffraction, and thermogravimetric analysis. The compound crystallizes in the orthorhombic space group Pccn, with cell parameters, a = 9.839(3) Å, b = 23.356(8) Å, c = 8.970(3) Å, V = 2050.2(8) nm³ and Z = 4.

Abstract: A new two-dimensional neutral framework generated from mixed organic ligands [Cu₃(1,2,4-BTC)₂(4,4^/-bipy)(H₂O)₄] (where1,2,4-BTC = 1,2,4-benzenetricarboxylate), has been prepared under hydrothermal condition and characterized by single crystal X-ray diffraction and magnetic susceptibilities. Its structure contains two different one-dimensional chains for the Cu ions, namely [Cu₂(1,2,4-BTC)₂]_n^2n- and [Cu (4,4^/-bipy)]_n²ⁿ⁺, respectively; the carboxylate of 1,2,4-BTC ligands links the two different 1-D chains into a interesting steplike supramolecular neutral framework, which exists ferromagnetic interactions between the copper centers.

Abstract: Three zinc (II) complexes of the amino acid Schiff base were synthesized by the one step reaction of amino acid with aldehyde, zinc acetate in solvent-free. The compositions and structures of the complexes were characterized by elemental analyses, FTIR, XRD, TG-DSC. The compositions of the complexes are ZnL•nH₂O (L = sal-leu, sal-ala, van-leu; sal = salicylaldehyde; van = vanillic aldehyde; leu = leucine; ala = alanine). Infrared spectra of the complexes indicate that the Schiff base ligands are formed, zinc ion is coordinated to the Schiff base ligands as terdentate with O, O and N donors from carboxylic, phenolic and imino groups respectively, the coordination numbers of zinc ion is four. The possible pyrolysis reactions in the thermal decomposition process of the complexes, the experimental and calculated percentage mass loss are also given.