Applied Mechanics and Materials Vols. 341-342

Abstract: Magnesium and its alloys have excellent physical and mechanical properties for a number of applications. Unfortunately, magnesium and its alloys are highly susceptible to corrosion, which greatly restricts their further application. Anodic oxidation treatment is an effective method to improve the corrosion resistance of magnesium and its alloys. In the anodic oxidation process, organic additives have significantly effects on the performance of the oxide film. This paper reviews the research progress on organic additives, in order to provide some references for the research of the electrolyte in the anodic oxidation process of magnesium and its alloys.

Abstract: Nanosized WO₃-doped TiO₂ photocatalysts were synthesized by a simple hydrothermal method, and characterized by scanning electron microscopy (SEM) and BET surface area analyzer. The photocatalytic activity of undoped TiO₂ and WO₃ doped TiO₂ photocatalysts was evaluated by the photocatalytic oxidation degradation of methyl orange in aqueous solution. The results show that the photocatalytic activity of the WO₃ doped TiO₂ photocatalyst is much higher than that of undoped TiO₂.

Abstract: The author adopts Monte Carlo compute method to simulate the linear polymer chain lattice model in multiple chain systems of chain length n=20, 50, 100 while the volume fraction Φ=0.125, and makes a research on the variational situation of the size (measured with the mean-square end-to-end distance 2> and the mean-square radius of gyration 2>), shape (measured with the mean asphericity factor ) with changing of the interaction energy between solvent molecule and polymer chain segment molecule ε_PS. Results indicate 2>, 2> and have the changing rules that they become small with the increase of the ε_PS

Abstract: The electronic structure expression of graphene was derived using tight-binding approxi-mation method. According to periodic boundary conditions in width direction of graphene nanorib-bons wave vector, the electronic structure analytical expression of armchair graphene nanoribbons was deduced, and the energy band curve were given. The conditions of graphene nanoribbons being metal or semiconductor were obtained. The results show that when nanoribbons width meets L=3na/2, the energy gap is zero and armchair graphene nanoribbons behave as the metallic. With the increase of the nanoribbons width, the energy gap of semiconducting nanoribbons decreases. The electronic properties of graphene nanoribbons are closely related to their geometry. The graphene nanoribbons can be modulated into metal or semiconductor with different band gap by controlling their width.

Abstract: Retracted paper: InGaN with high InN molar fraction is a promising material for next generation optoelectronic devices and electronic devices such as solar cells, laser diodes for communications, and high mobility transistors and so on. However, the growth of InGaN with high InN molar fraction is still a tough challenge for metal organic chemical vapor deposition (MOCVD). This paper provides experimental clues for the key factors, including the influences of the growth temperature, the V/III ratio, the group III supply ratio, and the reactor pressure. In addition, the effectiveness of the pressurized MOCVD growth of the InGaN with high InN molar fraction will be testified.

Abstract: Continuous cooling transformation (CCT) curves of deformed austenite (A) of Nb-Ti microalloying high strength steel were measured using Gleeble-3800 thermo-mechanical simulator, and corresponding transformation and structure were analyzed, and the effects of cooling rate on the tested steels mechanical property were studied. The resultes showed that the Ar₃ transformation point decreased with increasing cooling rate after hot-rolling. The morphology of ferrite (F) grains changed from polygonal to lath, and the pearlite (P) colonies became more fine with increasing cooling rate. The quantity of ferrite and pearlite decreased, and the quantity of bainite (B) and martensite (M) increased. Then the hardness of Nb-Ti micro-alloyed steel is increased along with the increasing cooling rate, which may owing to the reasons that the hardness of ferrite and pearlite is far smaller than that of bainite and martensite, and the grain refinement causes the hardness increasing.

Abstract: Poly (amidoanime) (PAMAM) dendrimers contain numerous amino-terminal groups and are highly hydrophilic. These terminal groups make PAMAM molecules adsorbed onto graphene oxide (GO) nanosheets through electrostatic action with oxygen containing groups on graphene oxide nanosheets. The PAMAM molecules react with GO, and form stable aqueous suspension of modified reduced graphene oxide (RGO).

Abstract: Solutions of lyotropic cholesteric liquid crystalline hydroxypropyl cellulose (HPC) in water would be self-colored due to the selective reflection of visible light, depending on the solution concentration. Colored coating of the liquid crystalline aqueous HPC solutions was attempted to apply. HPC solid films were found which could cast from the liquid crystalline solutions at different conditions such as solution concentration and different drying temperature. Experiments show that both solution concentration and cooling velocity play an important effect in controlling the color of HPC films.

Abstract: Multilayer films containing carbon nanotubes and redox polymer were successfully fabricated on a screen-printed carbon electrode using layer-by-layer (LBL) assembled method. UV-vis spectroscopy and electrochemical method were used to characterize the assembled multilayer films.

Abstract: Sr₃SiO₅:Eu²⁺ nanophosphors for white LEDs were synthesized by solgel method. The crystalline phases were examined with X-ray diffraction (XRD). Luminescence properties were studied, and effects of the Sr/Si ratio on the emission spectra were also studied. The nanophosphor showed a broad excitation band from 300 to 500 nm and a broad band emission peaking at 593 nm due to the typical electron transition of Eu²⁺ 4f⁷4f⁶5d¹. Remarkable enhancement in luminescence characteristics was observed when excesses silica was used. This phenomenon may be attributed to the improvement of Si sensitized the luminescence of Eu²⁺ in the Sr₃SiO₅ nanophosphor.