Advanced Materials Research Vol. 711

Abstract: In this paper, the dielectric constants of ER fluids with different particle concentration were measured by frequency method, and their electrical conductivities under different external electrical fields were also measured by method of conductivity cell constant. The results obtained from above measurements are as follows: the dielectric constant of ER fluid increases with the increasing of concentration; its electrical conductivity of the same concentration increases with the increasing of electrical field strength; for gradually increasing concentration, the conductivity first increases, then decreases. From analysis, it is suggested that the change of effective ion concentration of ER fluid is an important reason for its variation of conductivity.

Abstract: A technology of ‘Time-going-backwards’ is used to search isomers of C₃₆, molecular dynamic simulations of C₃₆ isomer evolution in He buffer gas at 2500K demonstrate that the isomers of low energy are important roles in the dynamics of C₃₆ and the lowest energy isomer—D_2d are the most important role.

Abstract: This paper discussed effects of organic matters/inorganic matters (OM/IM) ratios on the physical property, porosity and expansibility of ultra-light sewage sludge ceramsite (ULSC). The results indicated that ULSC with the high expansion and low water absorption were obtained when the OM/IM ratios were between 0.16 and 0.24. The OM/IM ratios had great effect on magnitude of physical forces of EF and ST; the relationship between EF and ST could determine pores formation and expansion of ULSC. Na-Ca feldspars of ceramsite grew as OM/IM ratios increased and the sintering process made some components of raw materials transform into other crystals having better thermostability.

Abstract: Due to the hazard bringing to human, Bisphenol A pollution problem has drawn more and more attention in water treatment field. This study has developed a kind of modified zeolite as absorbent to remove it. Natural zeolite and chitosan were adopted in experiments. Results indicated that the modified zeolite bore more pore volumn and specific area than natural zeolite. To modified zeolite, natural zeolite and chitosan the adsorption of bisphenol was finished in 6-8h. Modified zeolite showed relatively excellent adsoptive capicity in batch and column experiments. The Freundlich isotherm was suitable in describing the sorption behaviour. Organic matters in water might be an important factor to debase the adsorption. To practice application velocity of 4.2-6.1 m·h^-1 was suitable and the form of several column connected in serious was recommended.

Abstract: Several derivatives of 5-methyl-benzofuro [3,2-quinoline (O-isostere of cryptolepine) were synthesized. Spectrometric experiments and molecular modeling indicated that these derivatives interacted with duplex DNA by intercalation binding mode. The derivatives with aniline substituent exhibited superior DNA binding affinity to that of lead compound 5-methyl-benzofuro [3,2-quinoline.

Abstract: A conventional hot-pressing method was used to produce Al/Al-4wt%Cu functionally graded material (FGM). Heat treatment, which included solid solution treatment (T4) and aging treatment (T6), was carried out on hot-pressed (F) specimens. The creep crack growth tests were performed under constant loading of the creep-testing machines. The distribution of copper composition was investigated by line analysis via electron probe microanalysis. Fracture morphology and creep crack paths were studied by scanning electron microscopy. During heat treatment, the thickness of the graded transition layer increased due to copper composition redistribution. Creep crack growth retardation was found when crack propagated from the graded transition region to the Al-4wt%Cu layer. Greater improvement in creep crack growth resistance was achieved by the T4 and T6 states of Al/Al-4wt%Cu FGM. For T4 and T6 state specimens, the micro-cracks and crack kinking in the transition region were observed, which prevented creep crack growth.

Abstract: A commercial 2507 duplex stainless steel with different solution treatments followed by aging at 850°C has been investigated. At the early aging time of 850°C, the σ-phase precipitate was predominantly distributed at the δ/γ interface, as the isothermal aging time was increased to 150 min, more σ-phase precipitate formed in ferrite and became coarser by a eutectoid reaction δσ+γ₂. The amount of δ-ferrite decreased rapidly at the beginning of aging for 80 minutes, increasing solution treatment temperature from 1060°C to 1230°C delayed decomposition of δ-ferrite due to lowering σ-phase formation element (Cr). The reaction rate K and σ-phase precipitation rate were lowered by increasing solution treatment temperature from 1060°C to 1230°C.

Abstract: The effect of RE on modifying inclusions of 10PCu weathering steel was studied by metallographic examination, SEM and electron spectroscopy. Thermodynamic calculation was used to analyze the formation of RE inclusions in 10PCu weathering steel. The result shows that aluminosilicate inclusions are modified to round RE complex inclusions after adding RE to 10PCuRE steel.

Abstract: The effect of Ce on structure and mechanical properties of 21Cr11Ni austenitic stainless steels were studied by metallographic examination, scanning electron microscope (SEM), tensile test. The results show that the proper amount of Ce can refine microstructure of austenitic stainless steel. Fracture is changed from cleavage to ductile fracture by adding Ce to austenitic stainless steel. 21Cr11Ni stainless steel containing 0.05% Ce can improve its high temerature strength, and the strength is increased 21.81% at 1073K respectively comparing with that of 21Cr11Ni stainless steel without Ce.

Abstract: The effects of rare earth metals on the inclusions and the mechanical properties of 21Cr11Ni austenitic steel were studied by scanning electron microscope (SEM) and energy spectrum analysis. The results show that the morphologies and sizes of inclusions in 21Cr11Ni stainless steel are changed, and rare earth played a very good role of modifying inclusions. The fracture mode of 21Cr11Ni stainless steel is typical cleavage fracture, but quasi-cleavage and dimple fracture after adding RE into the steel. The transverse impact toughness of 21Cr11Ni stainless steel is improved obviously by RE. In comparison with 21Cr11Ni stainless steel without RE, the transverse impact toughness of 21Cr11Ni stainless steel with RE is increased 25.33% at-40°C, and the room temperature strength are improved, the elongation and reduction of area have been improved 9.18%, 12.71% respectively.