Advanced Materials Research Vols. 197-198

Abstract: This article analyzed different filament amount and twists effect on the CCFs’ conductivity and stability of resistance under different elongation, and observed the surface of CCFs by SEM. The study demonstrated: In the initial state, the experimental resistance value of CCFs’ is close to the theoretical one; The conductivity would improve as the number of filament and twist adding; The relationship between resistance and elongation varies differently in two periods during the stretching: within 0-6mm, CCFs' varies of resistance is more stable, but unsteadily within 6-15mm, and the coat of some samples began to break off.

Abstract: IPMC (ionic polymer metal composite), a kind of ionic electroactive polymer (EAP) has wide applications in the filed of bionics and artificial apparatus for its fast and large bending deformation under the low driving voltages. In this paper, thick IPMCs with various numbers of films were first fabricated by the hot-pressing method. Then the effect of the thickness on its properties, such as the tip forces and water uptake capability, were investigated. The effect of length of the IPMC on its tip forces was further studied. SEM (scanning electron microscopy) micrographs of IPMC specimen were also examined.

Abstract: Perovskite type ferrite doped with Sr²⁺, Dy_1-xM_xFeO₃(x = 0.0, 0.05, 0.15, 0.25) were prepared by the conventional solid-state reaction. The structure and electromagnetic properties of the calcined samples were studied using powder X-ray diffraction (XRD, Rigaku D/Max-2500) and network analyzer (Agilent 8722ET). All the XRD patterns showed the single phase of the perovskite type ferrite without other intermediate phase when x≤0.25. The electromagnetic properties of the samples have been studied at the frequency range from 2 GHz to 18 GHz. The ε′ and ε′′ values were improved significantly. Both the values of ε′ and ε′′ increase with the increasing content of the doped cations Sr²⁺, and the peak value of ε′′ was about 2.2 at 12.1 GHz position when x = 0.25.

Abstract: The silicone succinate ester surfactant (PMPS) was synthesized by the raw materials of polyether alcohol amine modified polysilosane (PAPS) and maleic anhydride (MA) at 90°C for 4.5h, and p-toluenesulfonic acid (PTSA) was used as the catalyst. Sulfated neatsfoot oil, oxidized-sulfited fish oil was mixed with PMPS to prepare a new leather fatliqour (F-1). The structure of the materials and PMPS were characterized by FTIR. The biodegradability of F-1 was analyzed by BOD₅ and COD_Cr and the tissue slices of the leather samples oiled by PMPS were observed by Multimedia Microscope to study the fatliquoring effect. The waterproof properties and the fatliquored leather were determined. All the results indicated that the F-1 fatliquor has good fatliquoring effect.

Abstract: In order to reduce the oxidizing and volatilizing caused by Mg element in the traditional methods for synthesizing Mg₂Si_l-xSn_x solid solutions, Mg₂Si_l-xSn_x solid solutions have been prepared by Microwave-assisted Synthesis techniques. The heating behavior of Mg, Si and Sn fixed powder was investigated under microwave irradiation. X-ray diffraction (XRD) was used to characterize the powders. The results suggest that the temperature-rising rate is also dependent on the initial green density and higher green density provides lower heating rate while power setting are fixed. XRD patterns show that Mg₂Si_l-xSn_x solid solutions have been well formed under microwave irradiation.

Abstract: A novel unsymmetrical diarylethene derivative bearing both phenyl and thiophene moieties, in which a trifluoromethyl group was substituted at the meta-positions of the terminal phenyl ring, was synthesized. At the same time, its photochromic properties and fluorescence switch were investigated in detail. The results showed that this compound exhibited reversible photochromism, undergoing reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light both in solution and in PMMA film, and its absorption maxima were observed at 584 nm in hexane and at 593 nm in PMMA amorphous film, respectively, upon irradiation with 297 nm UV light. The fluorescence intensity of diarylethene decreased dramatically along with the photochromism from open-ring isomer to closed-ring isomer upon irradiation with 297 nm UV light in PMMA. In hexane solution, the open-ring isomer of the diarylethene 1 exhibited relatively strong fluorescence at 420 nm when excited at 322 nm.

Abstract: The effect of 1mol% calcia additive on sintering of yttria was investigated, and a yttria with elongated grains and micro-pores was developed in present work. The results showed that in calcia added samples heated at 1600°C, calcia contained yttria solid solution grains were formed and distributed among pure yttria grains. With the prolonging soaking time, they were concentrated into rod- or plate-like elongated grains and some of them were embedded into pure coarse yttria grains. Furthermore, in calcia added samples, grain growth was much faster and lots of micro-pores were left in coarse pure yttria grains. Water quench test revealed that thermal shock resistance of calcia added sample was greatly improved by elongated grains and micro-pores.

Abstract: Corundum–mullite based ceramic foams were prepared by adopting foam impregnation process with raw talc and kyanite as modifiers. By comparing the sinters strength among the original formula with and without talc and kyanite added, it can be seen that when 6wt% raw talc was added, the compressive and flexural strength of the sintered foam ceramic bodies are increased by 108.9% and 33% respectively more than the original formula. Adding 4wt% ball-milled kyanite on this basis, the compressive and flexural strength were further elevated 20.1% and 29.1%, respectively, and meanwhile, the sintering shrinkage rate was dropped by 54.2%.

Abstract: Li₂O-Al₂O₃-P₂O₅-SiO₂ xerogel powders were synthesized by sol-gel route and glass-ceramics were prepared under different forming pressure and sintering temperature. The effects of sintering temperature and forming pressure on coefficient of thermal expansion of prepared glass-ceramics were investigated by means of DTA-TG, TEC and XRD. The results indicate that xerogel powders crystallization begins at 785°C, and the main crystallite phases in the researched specimens are virgilite and cristobalite. The TEC decreases linearly with the forming pressure. When the sintering temperature is 950°C and forming pressure is 40MPa, a low TEC of 0.65×10^-6 °C^-1 can be obtained.

Abstract: In this paper, the influence of thickness and density of nonwoven materials on the sound-absorption capability is studied through the serial experiments. The results show that the sound-absorption coefficient increases with material thickness increasing and this relationship is more distinct for low or mid frequencies than for high frequencies. When the material thickness is made constant, the sound-absorption coefficient increases with density increasing for low-mid frequencies, while the coefficient decreases with density for high frequencies. The conclusion is that the nonwoven materials with low density structure own better capacity in absorbing sound according to the experiment results.