Applied Mechanics and Materials Vols. 395-396

Abstract: In the paper the basic information about hydrogen were given. The most important parameters from energetic point of view were described. The efficiency and other work parameters were shown in the form of graphs.

Abstract: To increase active property of aluminum anode material and decrease its corrosion rate, the effect of urotropine ((CH₂)₆N₄) and saturated Ca (OH)₂ environment-friendly additives on electrochemical behaviors of aluminum anode (99.999%) has been investigated by adding urotropine and saturated Ca (OH)₂ into 4 mol/L KOH solution. The results show that additive urotropine ((CH₂)₆N₄) can decrease the hydrogen-segregation and can increase activation property of aluminum anode greatly. With 1.0 % (w) of urotropine ((CH₂)₆N₄) and saturated Ca (OH)₂ addition in 4mol/L KOH solution, the corrosion current of aluminum anode becomes to minimum; its corrosion-inhibition ratio gets high to 87.3%. At the-1.20 V potential the current density of aluminum anode reaches to 37.7 mA.cm^-2; the open circuit potential (E_ocp) moves negatively and greatly to-1.815 V.

Abstract: The V₂O₅ films were prepared by the (radio frequency)RF sputtering. The transmission of the samples under different deposition pressures and different Ar/O₂ flow ratios was investigated to determine the fundamental preparation condition for the further analysis. On the fundamental condition, the security volt of V₂O₅ was determined. It is concluded that the annealing makes the V₂O₅ films have a good reversibility but lowers the electrochromic property.

Abstract: The failure analysis of a fly through frangible canister cover is studied based on transient dynamics via the finite element method. The cover, which is fabricated with five plan-liked parts, is cohesively bonded together forming several weak paths. Five test specimens are designed according to the length of bonded fiber cloth. The cover is subjected to an impulsive blast and the failure process is obtained and analyzed. The failure pressure and time are determined at different cloth length. The result shows that the failure pressure and the corresponding time rise as the length of bonding layer increases.

Abstract: With good vibration alleviating property, resin mineral composite has been used to produce main components of machine tools to satisfy the requirements of machining efficiency. Bubble in RMC is one of the key influences on compression strength, its amount and distribution determines the overall mechanical properties of the composite directly. In this article, bubble nucleation and free energy theory are used to explain the generation mechanism of bubbles by subdividing them into two parts, bubbles generated in granite and bubbles generated in resin. Mechanical model of single raised bubble in micro cylinder channel is established based on the flow characteristics of non-newtonian fluid. In order to validate the aforementioned assumptions, typical RMC samples are produced. Strength test and draining method are used to get their compression strength and bulk density. Experimental results show that sample with vacuum pouring process has smaller bubble amount and better compression strength performance, which is consistent with the mechanical model.

Abstract: The effects of thickness on the impact damage of composite laminates were discussed in this paper. Impact tests for the composite laminates with the size of 600 mm×700 mm with three different thicknesses were subjected to impact energy levels from 5 J to 40 J. The crater depth and matrix length were investigated according to different energy levels and different thicknesses. The impact damage was evaluated by visual inspection, three-dimensional microscope. The experimental results reveal that the crater depth and the crack length increase with the increasing impact energy. The thickness had the negative effects on the impact damage of the specimens at the same impact energy.

Abstract: The effects of the thickness and the impact energy on the medium leakage of CFRP laminates were discussed in this paper. Impact tests for CFRP laminates with the size of 600 mm×700 mm with three different thicknesses were subjected to impact energy levels from 5 J to 65 J. The medium leakage and the damaged area were investigated according to different energy levels and thicknesses. The damage area was evaluated by visual inspection and three-dimensional microscope. The experimental results reveal that the impact damage of CFRP laminates tends to be more severe as the impact energy increases, and the impact area and the crater depth increases with the increasing impact energy. For the same impact energy, the impact area and the crater depth decrease with the increasing thickness.

Abstract: A new class of three-armed star-shaped liquid crystals 5a-5d were synthesized, they used 1,3,5-trihydroxybenzene as a core, ω-[4-(p-ethoxybenzoloxy) phenoxycarbonyalkyl acid (3a, 3b) and ω-[4-(p-nitrobenzoloxy) phenoxycarbonyalkyl acid (3c, 3d) as mesogenic arms. Their chemical structures were confirmed by FTIR and ¹H NMR spectra. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and thermogravimetric analyzer (TG) measurements. The results showed that the three-armed star-shaped liquid crystals exhibited a broad range of liquid crystalline phases at moderate temperature. The mesogenic arm structures obviously affected the phase behavior. As the intermedius alkyl chain of the star-shaped compounds lengthened (from n=4 to n=8), their melting points decreased but mesomorphic temperature ranges increased. The temperatures when 5% weight loss occurred (t_d) were higher than 300°C, which revealed that the synthesized three-armed liquid crystals had a high thermal stability. Threadlike, droplet and schlieren texture, typical of nematic phase can be observed in the liquid crystalline state during heating or cooling process.

Abstract: In this paper, the stability of carbon fiber reinforced plastics (CFRP) cylinders under axial compression was studied by the finite element analysis method. According to the Riks method, compressive capacity of the composite structures was investigated by nonlinear analysis, in which the eigen buckling modes were considered in the form of initial defects. And the post-buckling performances of different structures were also compared.

Abstract: Ce:Mn:LiNbO₃ single crystals were grown from the melts with different [Li]/[Nb] by top seed crystal method, while the concentration of Ce was 0.1mol% and the concentration of Mn was 0.015wt%. The concentration of each element in the crystal was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The location of the doping ion in the crystal was studied. The results revealed that Ce (or Mn) replace the location of Li in the Ce:Mn:LiNbO₃. The dependence of crystal constitute on the material proportioning is given in the paper. The exact chemical formula was given by the relationship between the composition of crystal and the raw material on the basis of the Li vacancy model.