Advanced Materials Research Vols. 239-242

Abstract: To a laminate model of 3D four-directional braided composites with periodic transverse cracks, a new normal stress function in weave direction is present. In this function, variations of stress with x and y are considered. By using the principle of minimum complementary energy, stress components in the representative unit are obtained. Tensile modulus of 3D four-directional braided composites with periodic transverse cracks is calculated by utilizing Hashin’s average theory and the principle of minimum complementary energy. To demonstrate the solution, some examples are analyzed.

Abstract: Anthraquinone dye Reactive Blue (KN-R) is first selected as the model dye to test the treatment of UV-vis/Ferrioxalate/H₂O₂ system. The effect of parameters Fe²⁺/H₂O₂, pH and H₂C₂O₄ are synthetically assessed. The optimum concentration is obtained at 1:15 of Fe²⁺/H₂O₂ and 30mg·L^-1 of H₂C₂O4 at pH=3.0 in 30min. Under the optimum condition, the removal rate of color, chemical oxygen demand (COD) and total organic carbon (TOC) are more than 99%, 87.7% and 66.8% respectively. The results show that the reaction accorded with a pseudo-first-order and the degeneration velocity of KN-R is 0.2459[dye](mg·L^-1/min).

Abstract: Use of transparent synthetic soils to visualize flow problems has recently been developed with an optical system and digital image processing. This paper proposes a new water-based transparent material called Aquabeads suitable for modeling natural soils. As feasibility of using Aquabeads to visualize geoenvironmental problems, surfactant flushing tests were conducted to simulate Light Non-Aqueous Phase Liquid (LNAPL) ganglia transport through Aquabeads model with clay lens was performed. The upward migration of motor oil ganglia during surfactant flushing was visualized. Aquabeads possess advantages over available transparent synthetic soils ; water-based material, similar macroscopic hydraulic characteristics to natural soils, compatible with water- oil- selected surfactants-alcohols used for simulating multiphase flow. Therefore, it is ideal for visualizing 2D flow, and soil contamination problems.

Abstract: According to the requirements of aluminum conductor composite cores, a kind of resin system was developed with TGDDM as main body, and self-made flexible epoxy SUC-1 as auxiliary, plus methyl hexahydrophthalic anhydride as curing agent. The gel rate of the system was high enough to meet the demands of pultrusion technique. The heat deformation temperature of cured sample reached 194°C, and the tensile strength achieved 62.95Mpa. The elongation at break matched that of carbon fibers. The interfacial bonding between the matrix and the fibers, observed by scanning electron microscope, was tight without debonding phenomenon.

Abstract: Two related tricarbonyl rhenium complexes with the formula of [Re(CO)₃(L)Cl], where L=4,5-diazafluoren-9-one (Dafo-Re) and 9-(phenylamino)-4,5-diazafluoren (PADF-Re) were successfully synthesized with the aim to explore the effect of the geometry of Dafo on Rhenium(I) coordination, and characterized by ¹H NMR. Photophysical behaviors are investigated by UV–vis absorption and Fluorescence spectra. The two complexes Dafo-Re and PADF-Re show metal-to-ligand charge transfer absorptions at ca.391nm, ca.394 nm and emissions at ca.492nm, ca.470nm, respectively.

Abstract: Aromatic polyesters bearing pendent carboxyl functionalities were prepared by interfacial polycondensation of diphenolic acid, bisphenol A and isophthaloyl chloride with tetrabutylammonium chloride as phase transfer catalyst. The copolyester composition was confirmed with HPLC analysis. The polymerization process and composition of the copolyesters were examined by considering influences of reaction temperatures, time, ratio of feeds, agitation speeds.

Abstract: A novel dendronized cellulose，ethyl cellulose grafted 3,4,5-tris[4-(dodecyloxy) benzyloxy] benzoate (EC-g-DOBOB), which is comprised of ethyl cellulose (EC) backbone with mesogenic moiety DOBOB (3,4,5-tris(4-(dodecyloxy)benzyloxy)benzoic acid) dendron grafted, was designed and synthesized. The structure of EC-g-DOBOB was investigated by means of FTIR, Both thermotropic liquid crystal and lyotropic liquid crystal behaviors of EC-g-DOBOB were studied by combination of DSC, POM and XRD. At room temperature EC-g-DOBOB demonstrated hexagonal columnar mesophase (Φ_h), with the column diameter 5.8 nm, besides it formed lyotropic cholesteric liquid crystal in concentrated chloroform solution with a planar texture.

Abstract: The NaA/PTFE composite membranes were synthesized on polytetrafluoroethylene (PTFE) film by hydrothermal secondary growth (HSG) method and scratching (ST) method. The structure and morphology were characterized by XRD and SEM. The pervaporation(PV) performance of NaA/PTFE composite membranes were evaluated with dimethylformamide (DMF)/water mixtures. The XRD results showed that NaA/PTFE composite membranes kept the zeolite crystal feature of A type. The substrate, PTFE and zeolite were firmly combined together by the SEM photos. The results of PV showed that the flux and the separation factor of NaA/PTFE composite membrane prepared by HSG method with 4 crystallization times were 0.54 kg/m² h and 23, respectively. The flux of NaA/PTFE composite membrane prepared by ST method was much larger than that of NaA/PTFE composite membrane prepared by HSG method, but separation factor was lower.

Abstract: In this study, the electrical properties of as-deposited Sr_0.4Ba_0.6Nb₂O₆ (SBN) ferroelectric thin films on SiO₂/Si(100) substrates were improved by low temperature supercritical carbon dioxide fluid (SCF) process treatment. The as-deposited SBN ferroelectric thin films were treated by SCF process which mixed with pure H₂O and propyl alcohol. After SCF process treatment, the memory windows increased in C-V curves, and the passivation of oxygen vacancy and defect in leakage current density curves were obtained. In addition, the improvement properties of as-deposited SBN thin films after SCF process treatment were found by XPS, C-V, and J-E measurement. Finally, the mechanism concerning the dependence of electrical properties of the SBN ferroelectric thin films on the SCF process was discussed.

Abstract: Xanthan gum samples were irradiated in aqueous solution at different doses (0-120 kGy) of 60Co γ-rays. The changes of molecular weight and structures of irradiated xanthan gum samples were investigated and characterized by using gel permeation chromatography(GPC), X-ray diffraction (XRD), fourier-transform infrared spectra (FTIR), ultraviolet–visible spectral (UV–vis) analysis and rheometer. Results showed the molecular weight decreased gradually with increasing irradiation dose. The radiation chemical yields G(d) of xanthan gum was 26.55. FTIR spectra and XRD indicated that γ-irradiation introduced no significant changes into the structure and crystal texture, but UV spectra showed a distinct absorption peak at about 265 nm, increasing with irradiation dose, which was attributed to the formation of carbonyl groups or double bond. Apparent viscosity of xanthan gum solution decreased with increasing irradiation dose and remain basically constant with the prolonging of shear time after irradiation.