Advanced Materials Research Vols. 463-464

Abstract: Microstructure and tensile properties of canned forged Ti-45Al-(8-9)Nb-(W,B,Y) (at.%) were investigated. After canned forging at (α + γ) phase region, microstructure in the major part of the pancake was fully recrystallized duplex (DP) microstructure containing equiaxed γ grains and fine α2/γ lamellar colonies with a grain size of less than 30μm, while microstructure in the near surface zone was a mixture of fine-grained DP and retained cast structure. Due to solidification segregation, β (B2) phase existed at the grain boundaries and triple junctions. The alloy exhibited a good balance between both room temperature (RT) and high temperatures tensile properties, and the brittle-to-ductile transition temperature was about 760 °C. The fracture mode was predominantly transgranular fracture at both RT and high temperatures.

Abstract: The objective of this work is to investigate the relationship between nugget development and electrode displacement curves during micro RSW of stainless steel sheets. A DC transistor type micro RSW machine equipped with a real-time monitoring system was employed for this study. A laser displacement sensor was used to detect the displacement signals in the movement of upper electrode. This research can provide references for monitoring and control micro RSW quality using maximum electrode displacement. The results showed that electrode displacement increased rapidly at the initial heating stage of welding, and then at a reducing rate under normal cooling stage. The maximum electrode displacement is proportional to the weld current and is inversely proportional to the electrode force. An electrode displacement curve is an ideal monitoring signal can reflect the formation and growth of a nugget during micro RSW.

Abstract: Abstract. Recently, there has been increasting interest in the doping of nano-/microcrystal hosts with Sm³⁺. However, very few examples of Sm³⁺ doped YF₃ -based nanophosphors have been reported. In this paper, a variety of uniform YF₃:Sm nano-/microcrystals have been successfully prepared by a facile, effective, and environmentally friendly hydrothermal method. The morphology evolution process has been investigated by quenching the reaction at different time. Based on the results, a possible growth mechanism is presented in detail. The as-obtained YF₃:Sm nano-/microcrystals show strong yellow and red light emissions under room temperature, which is quite different from those reported previously and might find potential applications in fields such as light phosphor powers and advanced flat panel display devices.

Abstract: The new simple and effective grid remeshing method on crack propagation in brittle materials is successfully introduced which is under uniaxial compression. Numerical analysis is applied to brittle materials of a single pre-existing crack considering various dip angles, lengths and friction coefficient. According to linear elastic fracture mechanics theory, we introduce node moving method to guarantee the good shape of the grid in the process of crack growth, and set contact element between the friction surfaces, and then get the crack tip stress intensity factor by using quarter singular element. The influence of length, angle and friction coefficient on crack propagation is quantitatively described. The method is consistent with the experimental results and is effective in 2D problems.

Abstract: The proton/lithium exchange property of the garnet-related lithium-ion conductors Li₅La₃Ta₂O₁₂ is shown to occur at room temperature under ambient air. The internal friction, TGA analysis, and IR spectroscopy techniques are used to investigate the reaction mechanism. XRPD analysis demonstrates the topotactic character of the exchange reaction. The water gas in ambient air is adsorbed on the grain surface and then to exchange proton for lithium ion into the garnet structure,(Li_5-xH_x)La₃Ta₂O₁₂. The H⁺/Li⁺ exchanging processes are reversible. When the measured temperature is higher over 573K, the internal friction peak gradually shifts toward lower temperature and the like garnet-like phase is recovered.

Abstract: Activated carbon was modified by urea, potassium hydroxide and potassium respectively. The porosity of the samples properties was analyzed by nitrogen adsorption. Then it was used as adsorbent to catalyze and absorbed H2S from the gas based on dry distillation. The experiments in this paper were carried to study the effects including H2S concentration, impregnating solutions on adsorption of H2S on the modified activated carbon. The results showed that the adsorption capacity of the modified activated carbon was relevant with the kinds of pickling liquid and experimental conditions, On the whole, The lower was concentration of H2S, the higher would adsorption capacity of modified activated carbon be. At the same time the experiments also analyzed the samples of surface oxidation products through thermogravimetric analysis.

Abstract: The ash of Huadian oil shale is made to remove H₂S in this experiment. XRD and nitrogen adsorption experiments are used to analyze the physical and chemical properties of the ash, the results show that the ash of oil shale has many metal and nonmetal oxides, and also has much microporous and mesoporous, all above is helpful to remove H₂S. The sample is modified by different ways to see the change of adsorption capacity. the sample which is modified by alkali and sprinkler is the best adsorbent, but the sample which is modified by microwave does not increase the removal ability obviously.

Abstract: Adding Optical Brightening Agent (OBA) during papermaking has been widely used in modern papermaking industry in order to improve paper whiteness. Because of ISO standard data is based on the paper without OBA, it makes a great diversity of result in color reproduction, and causes the printing production not to meet international standards. This research contrasted ISO whiteness and chroma value of paper with different amount of OBA, analyzed spectral data and tone in color reproduction of paper with different amount of OBA, then got the law of the effect of the ratio of OBA on ISO whiteness and chroma value, and the effect on color reproduction tone level in printing process. It can provide the reference for adding OBA during papermaking.

Abstract: With density functional theory, the structural and electronic properties of Pt3 and Pt3M clusters (M=Au, Ag, Sn, Fe) have been studied. It is found that all the Pt3M clusters show planar and tetrahedral structures and their Pt-Pt bond lengths are larger than the bond lengths of Pt3. The effect of M doping on electronic properties of Pt3 clusters have been investigated. It is found that by adding one M atom, energy gaps of the corresponding clusters become smaller. The calculated results also indicate that M atom makes the highest energy level of Pt atoms shift highly, except for tetrahedral Pt3Au clusters. These may be good for analyzing adsorption problems

Abstract: There are given details about the cochleoid geometry and there are traced, based on equations, different areas of cochleoid, based on a supporting mechanism. They are shown the laws of variation of the curvature radius and of the tracer point coordinates. It is studied the material point movement on the cochleoid and there are presented relationships and diagrams for speeds and accelerations.