Applied Mechanics and Materials Vol. 703

Abstract: This article reports the effect of MnCO₃ addition on the grain refinement efficiency of AZ91 magnesium alloy. The results indicate that the addition of MnCO₃ has excellent grain refining efficiency for AZ91 alloy, which is mainly attributed to the Al₄C₃ particles formed in the melt, besides Mn is indispensable to grain refinement in Al-bearing magnesium alloys. There is an optimal addition amount of 0.6% at 740 °C and the grain size is reduced from 245 to 91 μm. At the same time, the corrosion resistance performance of MnCO₃-added AZ91is improved.

Abstract: In this work, the influence on the luminous efficiency of sapphire-based LED with different chip arrangement was studied. Three types of ten-chips LED with COB packaging including the circular, triangular and rectangular structures COB were fabricated respectively. It is indicated that the COB packaging with rectangular arrangement has the best luminous efficiency in three types of COB packaging structures. In conclusion, a better COB packaging way was developed.

Abstract: As soft materials, textile materials play important roles in primitive times. Through analysing the patterns in painted pottery, the article propose that the patterns can only be drawn by textile materials, so pens made of textile materials must have been existed in the New Stone Age. It can be deduced that there are two developmental stages of pens, the first is ‘the Old Pens’ stage, at which textile materials are directly used for drawing; the second is ‘the New Pens’ stage, at which textile materials and stick are bound together as pens. What’s more, New Pens predate the existence of painted pottery, as they are tools of drawing on painted pottery.

Abstract: In this work, thermal residual stresses and deformation of an aluminum/composite hybrid shaft was studied using ABAQUS FEM software. First, the thermo-chemical model of the curing process was described, and the curing parameters were determined. Then, a FEM model of the co-cured aluminum/composite hybrid shaft was build up using ABAQUS FEM software. Finally, the distribution of the thermal residual stress and deformation in the co-cured aluminum/composite hybrid shaft due to curing was obtained, and the effect of cooling rate was analyzed. The results show that residual stresses can be reduced obviously by reasonable cooling rate. The cooling rate also affect the degree of cure which influenced the mechanic property of aluminum/composite hybrid structure directly.

Abstract: Metal-organic framework UiO-67 was explored as a novel stationary phase for high performance liquid chromatography (HPLC). UiO-67 was, for the first time, homogeneously coated on carboxyl functionalized magnetic silica microparticles at low temperature (45 °C) by using a recently introduced liquid phase epitaxy (LPE) process. HPLC runs using the synthesized core-shell microparticles as stationary phase showed baseline separation for three phenol derivatives, applying gradient elution using acetonitrile and water as mobile phase. It also showed that UiO-67 has the largest affinity for 2,6-dichlorophenol among the phenol derivatives tested. The comparison of core-shell microparticles with 20 and 55 layers, respectively, of UiO-67 grown on the magnetic silica core proof that the UiO-67 shell determines separation behavior. Therefore, the use of UiO-67 core-shell microparticles as a stationary phase combines the advantages of a thin, homogenous MOF shell showing fast kinetics and good separation efficiency with the advantages of spherical silica microparticle cores offering high mechanical robustness and moderate pressure drop.

Abstract: To increase the molecular weight of poly (phenylene sulfide ether) (PPSE), a novel route has been developed via the reduction of poly (phenylene sulfoxide ether sulfide ether) (PPSOESE) precursor. The synthesis of high molecular weight PPSOESE is essential for the ultimate purpose. Effects of process parameters on preparation of PPSOESE were firstly investigated and the optimization was performed by response surface methodology (RSM). Average number molecular weight (M_n) and Yield of PPSOESE were defined as the experimental responses. The statistical analyses indicate that the most significant factor is monomer concentration, followed by reaction temperature and the interaction of reaction temperature • monomer concentration. Under optimal conditions, the and Yield responses were obtained as 1.78 ×10⁴ ±1.02 % and 93.6±1.3 %, which are in agreement with the predicted values of 1.80 ×10⁴ and 95.4 %, respectively. Structure of PPSOESE was also characterized. The highest intrinsic viscosity and yield of PPSE by the reduction of PPSOESE reached to 0.78 dL/g and 93.2%, respectively, much greater than the reported results. The work is helpful for forthcoming preparation and study of high molecular weight PPSE.

Abstract: The photocatalytic activity of polycrystalline TiO₂ samples impregnated with dendritic zinc phthalocaynine was investigated using the rhodamine B (RhB) aqueous solution as a probe. The morphology and structure of TiO₂/dendrimer phthalocyanine nanocomposite catalyst were characterized by X-ray diffraction (XRD) and UV-Vis spectra. Significant activity improvements of the TiO₂/dendrimer phthalocyanine nanocomposite photocatalyst were observed possible in terms of lower loading amount, enhanced photo-reactivity under light irradiation, as well as chemical, and photochemical stability of the sensitizers.

Abstract: Electromagnetic radiation has become a great threat to human health. In this paper, ferrite and graphite were main absorbing agent, which were prepared to a new type of anti-electromagnetic radiation gypsum board. The results show that the microwave absorbing properties of ferrite/graphite mixed are better than with ferrite or graphite single-agent mixed. The gypsum board with the graphite content of 5wt% and the ferrite content of 25wt% has the best absorbing performance, The effective band width less than-5dB of the samples is 7.1311GHz, and the maximum absorption peak-18.467dB.

Abstract: Slowing down processes for a proton and a carbon ion penetration through plasmas are studied within the dielectric response theory.The results show that the stopping power of ion will increase in lower projectile velocity, while the value of stopping power will decrease for higer velocity, and there is a maximum value for stopping power for some projectile velocity due to the resonace of excitation of plasmas. In addition, the stopping power will have higher value for carbon ion than proton due to the effects of charge states. Introduction

Abstract: Xylan preservative is a new type of wood preservatives ,which is not only harmless to humans and animals, but also no contaminates the environment. Through the extraction of corn cob xylan, anti-corrosion performance testing and compared with the CCA, the results shows that: white rot fungus specimen weight loss rates were: 2.53%, and CCA weight loss rates were 4.08%. In this paper, we carried out through cottonwoods of different states to measure, research and analyse the main chemical composition on their moisture content, benzene - alcohol extract content, lignin content and whole fiber content, which is for future improvement preservatives formulated to provide experimental data, through the comparison of chemical composition among different states of cottonwoods to find out how the effects of preservatives on cottonwood anticorrosive were. The experiments indicated that benzene-alcohol extractive contents of anticorrosion cottonwood and fresh cottonwood were close to 4.50% and 4.51%, while decayed cottonwood of benzene-alcohol content of drawn increased to 5.70%. Lignin contents of anticorrosion and fresh cottonwood were close: respectively, 22.10% and 22.55%, from 24.19% rotten cottonwood. The whole fiber content of Anticorrosion cottonwood, fresh cottonwood and decayed cottonwood were, respectively,66.62%, 84.55% and 64.19% .