Advanced Materials Research Vols. 148-149

Abstract: Wrinkling and tearing are the main failure modes in sheet-metal forming. The radius of die is important for deep-drawing because of an effective way to promote deep formability sheet metal .This paper presents an attempt to determine the effect of various elliptical shape die shoulder on the fracture and wrinkling and was investigated using 08Al sheet metal .The ellipse with minor axis of b=4.5mm and major axis of a=6.5mm,a=7mm,a=8mm ,a=10mm were analyzed to eliminate wrinkling and fracture in deep-drawing .The aim of this study is to investigate the effect of elliptical major axis and elliptical minor axis variables in elliptical shape die shoulder on formability in the deep-drawing process and to obtain useful date from the industrial field .The experiment show that limit formability promote with elliptical shape die shoulder in deep-drawing process.

Abstract: In order to investigate the performance of shape memory alloy wire, two types of alloy wire were studied. The results showed that the phase transition temperature of the superelastic wire were: Ms and Mf were 21.18 °C and 7.08 °C; As and Af were 12.32 °C and 25.13 °C. The phase transition temperature of memory effect alloy wire were that Ms =- 11.85 °C, Mf =- 29.37 °C, As = 36.77 °C, Af = 43.35 °C. By the tensile test of the SMA wire, the stress - strain curves of the two kinds of alloy wire were obtained.

Abstract: Various morphologies of ZnO nanostructures, including nanoparticle (NP), nanopetal and nanorod (NR) array, were fabricated via solution-phase approaches. The morphology and crystallization of resulting Nano-ZnO were investigated by Field-emission scanning electron microscope (FESEM), High resolution-transmission electronic microscope (HR-TEM), and X-ray diffraction (XRD), respectively. A dual-layered photoreceptor containing the nanostructures film as the charge generation layer (CGL) were designed and fabricated. It was found that the photoreceptor based on ZnO NR array as CGL exhibited better photoelectric performance than that from ZnO NP or nanopetal.

Abstract: A novel photoresponsive hydrogels of poly(acrylamide-co-acrylamido azobenzene) (p(AAm-co-AAAB)) consisting of acrylamide (AAm) and acrylamido azobenzene (AAAB) was prepared via a free-radical copolymerization route by using 2,2’-azobisisobutyronitrile (AIBN) as initiator, and N,N-methylene bisacrylamide (MBAA) as a crosslinking agent. The photoresponsive behaviors were studied. The variations of volume and swelling ratio of p(AAm-co-AAAB) hydrogels under UV or visible light irradiation indicated that PAAm hydrogels have no UV light sensitivity, but with the increase of the time of UV irradiation, the volume and swelling ratio of p(AAm-co-AAAB) hydrogels decreased, and then increased with the extending of the time after UV irradiation for the isomerization. The results disclosed that the copolymer hydrogels possess good photoresponsive property to UV irradiation, and the photoresponsive behavior is reversible with the transformation between UV and visible light irradiation.

Abstract: ZrO2 nanotube carrier was obtained using a direct anodization method. Then SO42-/ZrO2 nanotube catalyst was developed in the sulfuric acid solution through ultrasonic dipping processing. The morphology, thermal stability and crystal forms of catalysts were analyzed, and the influence factors of catalytic activity were studied. The results presented in this work show that the catalyst activity was highest under the following conditions: the mass fraction of sulfuric acid solution was 50 %, the ultrasonic dipping time was 20 min, the suitable calcination temperature was 400 °C and the calcination time was 60 min.

Abstract: The Magnetite (Fe3O4) nanoparticles have been successfully synthesized through a solvothermal route by using FeCl36H2O and NH4HCO3 as the starting materials. The as-prepared products are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), superconducting quantum interference device magnetometer (SQUID) and Brunauer-Emmett-Teller (BET). The uniform size of the Fe3O4 nanoparticles can be well controlled from 10 to 90 nm by changing the surfactants or the inorganic salts in the solvothermal process. The experiment results reveal that the magnetic properties of magnetite nanoparticles can be tuned by changing the particles size. In addition, the solvents in this reaction system have an important influence on the composition and morphology of the final products.

Abstract: Ba0.62Sr0.38TiO3 ceramics of perovskite structure are prepared by solid reaction method with the addition of x wt% NiO and their dielectric properties are investigated. It is found that Ni2+ can enter the B site in ABO3 perovskite when doping concentration is less than 0.6 wt%, whereafter, Ni2+ ions most segregates on the grain boundaries to inhabit the grain growth. Due to the decrease of grain size and the impurity, the dielectric constants are decreased. Decrease of dissipation factor is attributed to appearance of the oxygen vacancy and disappearance of the reduction of Ti4+ ion. It is concluded that the diffuse phase transition is linked to the adulteration of Ni2+. The disordering, mechanical stress in the grain and the oxygen vacancies are produced because of the adulteration of Ni2+, and the diffuse phase transition increases with the level of doping increasing, leading to that the peaks of dielectric constants becomes slower and flatter.

Abstract: Intelligent health monitoring system of the long-span railway cable-stayed bridge requires the comprehensive knowledge of instrumentation, analytical and information processing technologies with the knowledge and experiences in design, construction, operation and maintenance of railway cable-stayed bridge for long-term monitoring the performance throughout its lifecycle. It is necessary to perform sensor-based structural monitoring for identifying the bridge conditions in order to assure the structural safety and to evaluate the operational performance. The considerations for deploying a proper monitoring system are appropriate sensor instrumentation, robust signal acquisition, reliable signal processing, and intelligent signal and information processing. The experience on developing an autonomous monitoring system in the one certain railway cable-stayed bridge newly constructed is introduced in this paper. Sensor and hardware instrumentation, signal transmission, signal acquisition and analysis are schematically described mainly. Experience through this work will be worthwhile lessons for other similar efforts.

Abstract: Poly(ε-caprolactone) (PCL) glycol based casting polyurethane elastomers (CPUE) filled with nano-SiO2 particles within different surface properties were synthesized by mean of in-situ polymerization. The macro-static/dynamic mechanical properties and micro-dispersed state were characterized by an electronmechanical universal testing machine, a durometer, a rubber resilience experimental machine, a dynamic-mechanical analyzer (DMA) and a scanning electron microscope (SEM). The tensile modulus at 100% and 300%, elongation at break, tensile strength and tear strength of PCL urethane nanocomposites increased substantially in the presence of a certain amount of nano-SiO2 compared with their pristine state. Furthermore, the tensile strength and tear strength at 100 of the PCL CPUE with 5% nano-SiO2 pretreated by γ-glycidochloropropyl methyl trimethoxy silane (SI-CA) were 1.50 and 1.94 times than those of the pure PCL CPUE, respectively. The addition of the nano-SiO2 had little effect on the hardness, but the impact resilience decreased slightly. DMA analyses showed that the loss factor peaks of two nano-SiO2 polyurethane composites were higher obviously than the pure PCL CPUE and the glass transition temperature （Tg）of the two nano-SiO2 polyurethane composites increased to higher temperature region. SEM fractographs showed that the surface treatment by the optimum silane coupling agent influenced the dispersibility of nano-SiO2 in the PCL CPUE distinctly. The agglomerating phenomenon, and even some nano-agglomerates with more than 1 μm diameter can be observed in the PCL CPUE with 5% untreated nano-SiO2, but the nano-SiO2 pretreated by SI-CA was dispersed in the PCL CPUE in nano-scale.

Abstract: The Multi-Morphologic nanostructures of nickel sulfides were synthesized successfully by a solution chemical route. The growth models of these materials and the most possible mutation process between these different morphologies were discussed.