Advanced Materials Research Vols. 476-478

Abstract: Fe-8Mn-6Si-13Cr-6Ni-12Co shape memory alloys are characterized by a good corrosion resistance and a modest shape memory effect. Experimental tests of the corrosion resistance of Fe-8Mn-6Si-13Cr-6Ni-12Co have been studied and compared with the Fe-32Mn-6Si alloy using weight loss, free corrosion and polarization resistance tests. The shape memory effect measurement of the Fe-8Mn-6Si-13Cr-6Ni-12Co and Fe-32Mn-6Si alloys has been also tested after 5% of deformation. The results of corrosion experimental tests show that the Fe-8Mn-6Si-13Cr-6Ni-12Co SMA is not very active in the Na2SO4 solution at pH4 at room temperature. In addition, its corrosion resistance is better than the Fe-32Mn-6Si and almost similar to the 316L stainless steel. To improve the shape memory effect of the Fe-8Mn-6Si-13Cr-6Ni-12Co, a thermomechanical treatment has been applied by 8% prestrain in tensile and followed by heat treatment at 1320K for 1 hour. The results show an improvement in the shape memory effect after 5% of deformation in tensile test.

Abstract: The compressive strength and microstructural characteristics of fly ash based geopolymer with alkaline activator solution were investigated. The sodium hydroxide and sodium silicate were mixed together to form an alkaline activator. Three parameters including NaOH molarity, mix design (fly ash/alkaline activator ratio and Na2SiO3/NaOH ratio), and curing temperature were examined. The maximum strength of 71 MPa was obtained when the NaOH solution of 12M, fly ash/alkaline activator of 2.0, Na2SiO3/NaOH of 2.5 and curing temperature of 60°C were used at 7th days of testing. The results of SEM indicated that for geopolymer with highest strength, the structure was dense matrix and contains less unreacted fly ash with alkaline activator

Abstract: A thick film ZrO2-based NOx sensor feasible for diesel and gasoline engine applications has three diffusion paths, the size of paths has a great influence on sensor signal output. This paper studies the relationship between the pump current signal and the size of paths, the manufacture of NOx sensors of varied path sizes by the method of filling organics and then sintering at a high temperature to form a stable path, and detections of the sensors in a standard gas chamber. Then matching sizes of three paths are obtained.

Abstract: An ionic liquid supported catalytic system, chloromethylimidazole acetylacetonate Cobolt(Ⅱ) was successfully used in the RATRP of methyl methacrylate. The chemical structure of obtained PMMA was confirmed by FT-IR and 1H NMR. The polymerization process in the presence of ionic liquid was thoroughly investigated. The results revealed that this kind of initiator and catalyst system could promote RATRP of MMA with the desired characteristics, and the RATRP proceeded in a controlled manner as evidenced by kinetic studies.

Abstract: Slice specturm is investigated as data mining techniques in the fault diagnosis of hydraulic control valves in this paper. The characteristics of vibration signals obtained from the control valves have been extracted by means of analyzing the 2-dimensional of trispectrum, with the main goal of detecting a possible working condition including the normal and fault conditions. The experimental analysis shows that there are distinct bump values in the center of the two-dimensional slices of trispectrum space in the fault conditions, on the contrast, the bump values disappear in normal condition. The experimental and theoretical results have indicated that trispectrum is a more suitable tool for diagnosing the faults of the hydraulic control valves.

Abstract: Benzyl alcohol is used to react with isophorone diisocyanate at different temperatures. Dibutyltin dilaurate is used as catalyst. In-situ FT-IR is used to monitor the reaction to work out rate constant, Arrhenius equation and Eyring equation. The urethane reaction has been found to be a second order reaction, and the rate constant seems different between initial stage and final stage. The activation energy (Ea), activation enthalpy (ΔH) and activation entropy (ΔS) for the urethane reaction of different isocyanates groups are respectively calculated out, which are very useful to reveal the reaction mechanism.

Abstract: A series of new chromium(III) complexes bearing fluoro-substituted β-diketiminate ligands have been synthesized and characterized by IR and elemental analyses. When activated by modified methylaluminoxane (MMAO), these Cr complexes exhibited moderate or high activities for ethylene polymerization (up to 370 g.mmol^-1.h^-1). Various reaction parameters such as reaction temperature and Al/Cr ratio were investigated in detail. Further more, it was found for the first time that the catalytic behaviors of Cr complexes can be greatly influenced by the electronic effect of fluoro substituents. The introduction of electron-withdrawing fluoro groups to ligands can improve the catalytic performances compared with those bearing alkyl groups, but incorporation of more fluoro atoms would then decrease the catalytic activities.

Abstract: In this paper, we demonstrated a novel method for the preparation of highly conductive polyaniline (PANI) compounded with Sn(OH)4. We obtained the PANI directly in the oxidation polymerization system via simultaneous reaction of aniline (using ammonium persulfate, APS as oxidant) and SnCl4 in carbamide aqueous solution. The resulting PANI was compounded with Sn(OH)4 had been characterized by FTIR, UV-Vis spectroscopy, X-ray diffractometry, thermal analysis, scanning electron microscope and conductivity measurements, and the results showed that PANI was in well doped state due to the hydrolysis of APS and the complex between PANI and Sn(OH)4. We are sure this alkali-guided polymerization to obtain conductive PANI will lead to the preparation of a new class of PANI composites.

Abstract: Based on two typical cross-sections such as the circular and the near-elliptical of PTT/PET bi-component filament, the crimp modeling was established. It can be used to describe the relationship among the crimp morphology in Longitudinal, the cross-section characteristics and the shrinkage difference of two components. The cross section characteristics of PTT/PET bi-component filament with nearly circular and elliptical cross section were obtained. The average ρ∆ of T400 made by Dupont is 17.46μm and that made by Huvis is 11.09μm.

Abstract: The filtration effect of automobile engine oil filter materials have two different expression index,such as nominal filtration accuracy and absolute filtration accuracy.In fact,the nominal filtration accuracy is labeled by manufacturer,however,the absolute filtration accuracy is needed experiment testing only to know.After testing the absolute filtration accuracy of these ten kinds of oil filter materials,it is turned out that there is an obvious difference between these two filtration accuracy.So this paper is based on the results of the two filtration precision and established a linear regression equation of absolute filtration accuracy=2.922+0.631×nominal filtration accuracy.If only knowing of the nominal filtration accuracy of oil filter materials,then the absolute filtration accuracy can be computed from the linear regression equation instead of experimental testing of absolute filtration accuracy.What’s more,this linear regression equation is easy and simple and has some application value and practical significance.