Advanced Materials Research Vols. 239-242

Abstract: It is a way of preparing absorbing composite materials when nickel plating carbon fiber is arranged in epoxy matrix orthogonally. The results indicated that after carbon fiber T - 700 was plated by nickel, the absorbing properties were remarkably improved. In nickel plating carbon fiber/resin composite absorbing material, the distance and quality score of carbon fiber in the resin have important influence on absorbing properties. When the distance was between 5mm and 8mm, and quality score is in 0.53wt % ~ 2.16 wt %,we can get the absorbing material that was less than - 5db in the X band and - 10db in the Ku band.

Abstract: Ti(3nm)/Ni(10nm)/Ti(3nm) films were deposited directly on glass substrates using dc facing-target magnetron sputtering system at room temperature and in situ-annealed from room temperature(RT) to annealing temperature(Ta) 500°C, respectively. At Ta = 400°C, the gain size was about 15 nm, and the magnetic domains of the films distributed homogenously, and the magnetic domain cluster size was nearly 25 nm. The maximum perpendicular coercivity of Ti(3nm)/Ni(10nm)/Ti(3nm) films was 1360 Oe. The segregation or diffusion of Ti and the stress anisotropy played important roles to increase the coercivity. The intergrain interaction of films was obtained by δM plots. In annealing films, X-ray diffraction (XRD) profiles showed two diffraction peaks of NiTi monoclinic structure (002), (111) lattice orientations.

Abstract: Star-shaped porphyrin-cored poly(L-lactide) (SPPLLA) was synthesized using a tetra-hydroxyethyl terminated porphyrin as a core initiator and 4-(Dimethylamino)pyridine (DMAP) as a catalyst in THF at 50 °C. The molecular weight of as-synthesized polymer were measured by GPC and ¹HNMR. It was found that the molecular weight of SPPLLA could be adjusted linearly by controlling the molar ratio of L-lactide to porphyrin core initiator, and the molecular weight distribution was reasonably narrow. Furthermore, SPPLLA polymers showed similar UV-vis spectra compared with porphyrin core initiator. Consequently, this will provide potentially porphyrin-cored poly(L-lactide) for photodynamic therapy.

Abstract: Powdering and desquamation is prone to happen when galvannealed sheet steel is stampinged and Powdering or desquamation often happens at the fragile phase where Fe content is high. The fragile phase thickness of the coating of galvannealed steel sheet is correlative nearly to the coating anti-pulverization ability.So it is very important to measure the fragile phase thickness with the research of galvannealed sheet steel process. The fragile phase thickness of the same batch galvannealed sheet steel made by some steel plant is about 560~590nm when it is measured by glow ischarge spectrometer , fracture observation methods by SEM and metallographic microscope, the error is very little.

Abstract: The new comb-copolymers [polyacetylene–MPEG (polyethylene glycol monomethyl ether)] were synthesized with (nbd)Rh⁺[η⁶-C₆H₅B^- (C₆H₅)₃] as catalyst. The copolymers with moderate molecular weights (Mn) (13000-170000) and yields (31.6-47.3%) exhibited higher optical activities compared with chiral monomer, which accorded with the “Chiral Amplification” effect. The optical activity of the copolymers gradually decreased as the amount of MPEG increased. The maximum amounts of MPEG for successful copolymerization and optical activity of copolymers were 40%, 30%, 20%(mol%) as the Mn of MPEG was 350, 750,1900, respectively. The optical activity of copolymers could change at external environmental stimulation, e.g., decreased as methanol content increased.

Abstract: The misfit-layered copper-manganese oxides(CMO) was successfully synthesized by inserting Cu(OH)_X^Y+ into Buserite under hydrothermal conditions and characterized by X-ray diffraction, AAS, SEM, TEM and BET. The single misfit-layered CMO can be obtained when Cu/Mn mole ratio is 0.67. SEM and HRTEM reveal that the as-synthesized material is a sheet-like crystal and the interlayer distance corresponding to the spacing of [MnO₆] and [Cu(OH)_X^Y+] is 0.47nm.

Abstract: Soybean oil-based alkyd resin was prepared using soy-based polyol, maleic anhydride and phthalic anhydride. The soy-based polyol was obtained through the epoxidization of soybean oil, followed by ring-opening with methanol and, the hydroxyl values of soybean oil-based polyols used in this reaction is 169.93 mgKOH/g. In the reactions of soy-based polyol, maleic anhydride and phthalic anhydride, the molar ratio of hydroxyl value is equal to carboxyl value and the molar ratio of maleic anhydride to phthalic anhydride is 2:1, 1:1 and 1:2, respectively. 1% hydroquinone based on total reactants was used as inhibitor of polymerization, 1% dibutyltin oxide was used as catalyst.

Abstract: Large-quantity core-shell carbon spheres/Fe₃O₄ nanocomposites were synthesized via a simple solution method. The phase structures and morphologies of the composite had been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the carbon spheres were covered by a layer of Fe₃O₄ nanoparticles with a diameter of about 25 nm. Measurements of the electromagnetic parameters of the samples showed that microwave absorption properties of the carbon sphere-Fe₃O₄ nanocomposites were much better than that of the pure Fe₃O₄ or the mixtures of carbon spheres and Fe₃O₄ microspheres. The optimal reflection loss (RL) reached −37.8 dB at 14.8 GHz for a layer thickness of 2.0 mm, which is favorable for application of our samples in a wide frequency range.

Abstract: A magnetorheological (MR) fan clutch is introduced. Based on Herschel-Bulkley model, the equation of transmission torque developed by MR fluids is derived to compute the torque transmission ability in the MR fan clutch. The necessary gap and the need of MR fluid volume between two parallel circular discs of the clutch are carried out. The results indicate that, the transmission torque of the MR fan clutch developed rapidly depend on the yield strength of MR fluid. The necessary gap and the volume for the MR fan clutch can be obtained based on MR fluid properties, the desired control torque ratio, the angular velocity and load torque of the clutch.

Abstract: Tetragonal LaVO₄:Dy³⁺ crystals with novel shapes of rod, rod-bundles and needle-like flower were successfully synthesized via a facile and surfactant-free hydrothermal process. The products were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence spectroscopy (PL).The experimental results showed that the concentration of the precursor and the reaction temperature played important roles in morphological evolution of LaVO₄:Dy³⁺ crystals (NCs). It was found that needle-like flower LaVO₄:Dy³⁺ exhibited the highest B/Y value compared with rod and rod-bundle samples. Possible growth mechanisms of polymorphological LaVO₄:Dy³⁺ crystals were briefly discussed.