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The influence of anodized film on corrosion and electrochemical behavior of extruded magnesium alloy AZ63, cast and die-cast magnesium alloys AZ91D were investigated by using immersion technique, electrochemical methods, SEM, EDAX, IR and XRD. The results showed anodized film could improve remarkably corrosion resistance. Protection effect was different with the same anodizing process because formation status of anodized film of different materials was different. The formation status of anodized film was related to alloy microstructure as revealed by optical and scanning electron microscopy. The formatting process and casting method strongly influences the corrosion performance by affecting on the alloy microstructure. A tentative corrosion mechanism is presented explaining the corrosion behavior of anodized magnesium alloy.

The McMurry crossed coupling reactions of p,p′-disubstituted benzophenones (1) with pivalaldehyde (Pv) gave the corresponding ethenes (2) in fair to excellent yield. The observed geometrical selectivity is varied depending on a kind of p-substituent of the aromatic moiety of 1, when p′-substituent is limited to methyl. According to the known reaction mechanism, the reason why the geometry selection occurred is discussed by a conformational analysis of a possible intermediate, titanium bound pinacolate, and molecular orbital calculations of the starting carbonyl compounds. As a result, the selection is caused by electronic and stereochemical structures of anion radical of 1 and approaching mode of Pv anion radical to them. Distribution of a spin density and unsymmetrical nature of two aromatic moieties of anion radical of 1 provide predetermined pathway to bring about the pinacolate without any rotational conversion under the reaction conditions. Subsequent workup affords 2 with the observed geometry.

The charge-transfer reaction of tetraarylbutatriene 1 with tetracyanoethene (TCNE) in dichloromethane at room temperature was studied and we found a novel addition reaction. A red crystalline material 2 was isolated as an intermediate product which is converted slowly into dihydronaphthalene derivative 3 in dichloromethane but rapidly in protic solvent. The structure of the compounds was determined by X-ray crystallography. The detailed structure and the plausible reaction mechanism have also been discussed.

Nanocrystalline Cu particles were prepared by mechanochemical reduction of cuprite (CU₂O) with graphite in a high-energy ball mill. In order to gain an understanding into the possible mechanisms, the kinetic of the process was investigated using Johnson-Mehl-Avrami (JMA) model. It can be seen that theoretical calculation agrees well with experimental data. It was found that the most important effect of mechanical activation is the formation of the lattice defects and grain boundaries in addition to activated fresh surface areas during milling, which promote the reduction process. The Cu nanopowder was characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD and TEM results showed the nano-structure nature of the product processed under the synthesis conditions; the crystallite size was measured almost 30 nm in the 30 h milled powders.

This paper explores the mechanism design of a balloon machine representing a vending machine where consumers can select their desired shapes, as well as avoid bursting caused by manual inflation. Inside the machine, balloons are placed on the mechanism designed based on a waterwheel which rotates at a constant speed generated by motion among different sizes of gears. When rotating to the corresponding shaped balloon, the inflator will move under the opening to pull it out from the display point and start to inflate the balloon for the set number of seconds. After the inflation is completed, the glass door will open and the customer can take out their balloon. The main purpose of our development and design of the balloon machine is to improve the general balloon blowing and it is easy to prevent over-exposure and blast. The balloon machine can automatically inflate and detect the blowing time to improve the shortcomings of the balloon’s blast. In this way, it can effectively decrease sudden explosions and the number of frightened people.

Pedestrian-car interweaving is a prominent problem in old residential communities in Chinese cities. To achieve a better pedestrian-car separation to create a safe and comfortable living environment in old residential communities, this paper investigated the mechanism of the flows of pedestrians and cars on a road network inside an old residential community. A method for calculating the flows of pedestrians and cars was proposed to identify the road segments or nodes where the pedestrian flows are interlaced or intersected with the vehicle flows. This method was applied to the estimation of the traffic in the Wangyuehu Community of Changsha City, China. The estimated distribution of community network traffic and pedestrian-car interweaving sites was consistent with the actual situation.

In this paper, the influences of magnetic field on electromagnetic properties of water are experimentally investigated. The results clearly show that the magnetic field reduces the dielectric constant and resistance of water and increases its electric conductivity. In this study, we also find that the electric conductivity of magnetized water increases with increasing the frequency of externally applied electromagnetic field and magnetized time, but its dielectric constant and resistance are decreased with increasing the frequency of electromagnetic field and magnetized time of water. Then we can affirm that the magnetic field changes the electric properties of water. Finally, we discuss the mechanism of variation of electromagnetic properties in water, which are due to the changes of nature of charged ions and velocity of hydrogen ions as well as the changes of polarized features or dipole moments of free molecules and clusters including linear and ring hydrogen-bond chains of molecules in water under the influences of electromagnetic fields. Therefore, this study has important significance in science and can expand the applications of magnetized water in biomedicine and industry.

The enhanced photocatalytic activity of tungsten trioxide (WO₃) has been observed experimentally via doping with S element as different dopant types. Herein, a comparative study on the effect of different types of S dopant and native vacancy defects on the electronic structure and optical properties of WO₃ is presented by using hybrid Heyd–Scuseria–Ernzerhof 2006 (HSE06) density functional methods. Six possible models (S${}_{\mathrm{\text{O}}}$–WO₃, S${}_{\mathrm{\text{W}}}$–WO₃, V${}_{\mathrm{\text{O}}}$–WO₃, V${}_{\mathrm{\text{W}}}$–WO₃, S${}_{\mathrm{\text{O}}}$ + V${}_{\mathrm{\text{W}}}$–WO₃ and S${}_{\mathrm{\text{W}}}$ + V${}_{\mathrm{\text{O}}}$–WO₃) based on WO₃ are tentatively put forward. It is found that cationic S doping (the substitution of W by S) is more favorable than anionic S doping (replacing O with S), and both cases become easier to form as native vacancy defect is accompanied. The electronic structures of doped WO₃ depend on the type of dopant: anionic S doping results into three isolated levels in the upper part of valence band, while cationic S doping only induces an effective band gap reduction, which is critical for efficient light-to-current conversion. Interestingly, the isolated states near gap of WO₃ would appear as long as native vacancy defects exist. The introduced levels or reduced band gaps make the systems responsed to the visible light, even further to a range of 400–700 nm. These findings can rationalize the available experimental results and pave the way for developing WO₃-based photocatalysts.

This paper proposes a new method that obstacles are attached to both the suction and pressure surfaces of the blades to suppress cavitation development. A centrifugal pump with a specific speed of 32 is selected as the physical model to perform the external characteristic and cavitation performance experiments. SST $k-\omega$ turbulence model and Zwart cavitation model were employed to simulate the unsteady cavitation flow in the pump. The results indicate that the numerical simulation results are in good agreement with the experimental counterparts. After the obstacles are arranged, the maximum head decrease is only 1.37%, and the relative maximum drop of efficiency is 1.12%. Obstacles have minimal impacts on the variations of head and efficiency under all flow rate conditions. The distribution of vapor volume in the centrifugal pump is significantly reduced after obstacles are arranged and the maximum fraction reduction is 53.6%. The amplitude of blade passing frequency decreases significantly. While obstacles decrease the intensity of turbulent kinetic energy near the wall in the impeller passages to effectively reduce the distribution of cavitation bubbles, and control the development of cavitation. After the obstacles are set, the strength of the vortex in the impeller passages is weakened significantly, the shedding of the vortex is suppressed, flow in the impeller becomes more stable.

This paper concentrates on the study of the superplastic response of coarse-grained Al-Mg alloys under uniaxial tension at different temperatures (ranging from 400°C to 525°C) and strain rates (10^-2 S^-1, 10^-3 S^-1 & 10^-4 S^-1). The microstructures have been analyzed using optical (OM) and transmission electron microscopy (TEM). It has been observed that continuous re-crystallization occurs during hot deformation of the alloy at the temperature of 425°C and strain rate of 10^-2S^-1. At the temperature of 425°C and strain rate of 3.78×10^-3S^-1, this Al-Mg alloy has the maximum elongation to failure of 181%, which is sufficient for manufacturing of extremely complex shapes using superplastic forming technology. The constant strain rate sensitivity index m and TEM observations show that in this case deformation mechanism involved is dislocation glide. Recrystallization during the hot tension greatly enhanced the plasticity of the coarse-grained material at a strain rate of about 10^-2S^-1 and the maximum elongation changes as a function of the strain rate.