Applied Mechanics and Materials Vols. 556-562

Abstract: In the present study, a new zirconium oxide was prepared by the simple chemical precipitation and calcination methods. TEM analysis proved that the prepared ZrO₂ particles are nanosized particles with average size of 20-50nm and XRD further illustrated its crystal pattern in nature. The effects of solution pH suggest the adsorption of fluoride is pH-dependent process and optimal pH values 2.0-3.0. In addition, the the adsorbed fluoride could be readily regenerate by dilute alkaline solution.

Abstract: The activated carbon-containing catalysts (Pd/C and Pt/C) have been prepared by surface modification of the activated carbon with palladium chloride and chloroplatinic acid solution, respectively. The Pt/C catalyst is characterized by XRD pattern. The glyphosate is prepared from catalytic oxidation N-phosphonomethyl iminodiacetic acid. Effect of different catalysts and amount of the catalyst in catalytic oxidation are investigated. Compared with Pt/C catalyst, Pd/C catalyst is more active. Optimum amount of Pd/C catalyst is 45 mol/m3 PMIDA.

Abstract: Nowadays, with the development of the high frequency and short wave radar system, the facilities are becoming more and more precision. This paper shows a very important part of the 340GHz radar system, which is the design of polarizing converter in the transceiver isolation network. Because of the big limit in the systemic error of the quasi-optical polarizing converter which is based on the principle of orthogonal polarizing isolation, here we use the latest technology – Metamaterials, to design the polarizing converter depending on its anisotropic property. Finally we find that the result of the periodicity polarization in 340GHz is good.

Abstract: Objective On the basis of the experimental investigation of Fe-ZrO₂ nanocomposite coating, nanoZrO₂ particles were added to the bath to prepare the nanocomposite coating of Fe-ZrO₂ with electroplating methods and laser cladding. Methods Study the effects of nanocontent, cathodic pulse current density, duty cycle, the ultrasonic frequency content of the coating surface Nano, orthogonal optimization of process parameters. Results The results show that nanoparticles concentration 10 g/l, the cathode current density pulse 4A/dm², the duty cycle 20%, ultrasonic frequency 180W, nanocomposite coating capacity of up to 5.5wt%. Conclusion Fe-ZrO₂ nanocomposite coating improved abrasion and Corrosion of the binary composite coating.

Abstract: In this paper, the sacrificial anode protection system for steel pile of Tripoli wharf (Lebanon) was studied. Optimal average protection current densities were selected for steel pipe/sheet pile of seaside zone back filled zone and sea mud zone. Based on field test and investigation, we found that the optimal average protection current density for seaside zone is 0.060 A/m², back filled zone 0.030 A/m² and sea mud zone 0.025 A/m², respectively.

Abstract: Twenty-four Cacl₂/ENG molded composite adsorbents specimen were successfully prepared by aqueous solution and squeezing method. The thermal conductivities of the samples were tested by nanoflash LFA447. The experiment results show that: the thermal conductivity perpendicular to the direction of compression is over 1.2 times higher than that parallel to the direction of compression, which prove that the thermal conductivity is anisotropic. Within a certain range, the thermal conductivity is enhanced with increasing density and decreasing mass ratio. Under mass ratio is 2:1 and density rise from 600 kg/m3 to 700 kg/m3, thermal conductivity increase fastest. Density and mass ratio has coupling effect on the thermal conductivity of Cacl₂/ENG molded composite adsorbents.

Abstract: By virtue of uniaxial cyclic loading and unloading tests on cemented backfill, the studies were carried out, which are mainly on the micro crack evolution characteristics and the AE fractal characteristics in various stage of micro crack evolution. The results show the value of AE energy and fractal dimension are high in the micro holes compaction stage. By contrast, the AE energy and the fractal dimension are at the lowest level in the micro cracks compression phase. In the micro crack stable development stage, the AE events become active, and the fractal dimension keeps a steady growth trend. Finally, with stress further increasing, the AE will take on a quiet period in which the AE energy is high and the AE fractal dimension drops continuously to the lowest value till the stress reaches at peak value of the cemented backfill.

Abstract: Recent advances in synthesis and controlled assembly of monodisperse colloidal nanocrystals into superlattice structures have enabled their applications in optics, electronics, magnetic storage, etc. Morphology controllable silver nanoparticles exhibit numerous unfamiliar characters and have achieved extensive applications in many fields. When applied in solar cells, the silver nanoparticles are used as a catalyst in the preparation of silicon-based antireflective layers, and also the varied morphology silver nanostructures can be utilized for silver paste which makes up the electrode. During the applying process, the size and morphology of the silver nanoparticles are important factors which influence their properties. The paper introduces the morphology category and preparation method of the silver nanoparticles. The effects of the morphology of the silver nanoparticles on their properties are discussed, and the further development of their application in solar cells is prospected.

Abstract: Intercritically treated ultra high strength steel was investigated using a continuous annealing simulator of the laboratory. The results have shown that the microstructure consists of a ferrite matrix with martensite. A satisfactory mechanical property was obtained by intercritical annealing and subsequent overaging. The specimen exhibited optimum R_m (1360MPa) and A_t (20%), a relatively low R_p0.2/R_m (0.72) and an ideal product of R_m and A_t (27200MPa%). Satisfactory mechanical properties of the present steel are attributed to the fact that the effect of dispersion strengthening of martensite islands as well as the contribution to strength by the softer phase, such as ferrite (retained austenite).

Abstract: Overaging after intercritical annealing of ultra-high strength multiphase steel was conducted in a continuous annealing simulator of the laboratory. The effect of overaging temperature on the mechanical properties of multiphase steel has been studied by observing the microstructural evolution during overaging. The results have shown that multiphase microstructures containing ferrite, martensite, bainite and retained austenite were obtained by overaging treatments after intercritical annealing in ultra-high strength steel, and overaging temperatures affected all constituents of the microstructure. UTS and YS dereased with increasing overaging temperature, and TEL decreased after overaging at 350°C. A good combination of ultimate tensile strength (1400MPa), yield strength (795MPa), and total elongation (15%) was exhibited for the specimen overaged at 250°C. This was attributed to synthetic action of all constituents of ultra-high strength steel microstructure.