Advanced Materials Research Vol. 486

Abstract: The simple way to synthesize crosslinkable multi-branched ethynyl fluorene-labeled molecules has been reported in this work. A three-armed molecule, OxDBFP is prepared by cyclotrimerization and phase transfer catalysis methods. 3-(6-Bromo-2-oxahexyl)-3-methyloxetane tethered to 9-position of fluorene is crosslinked when exposed to UV light. This kind of compounds can be proper candidates for full-color displays or solid-state lighting by low-cost solution prosessing.

Abstract: This research performed a series of triaxial tests on sandy specimens to obtain the parameters needed for a constitutive model. The model is capable to simulate the strain hardening/softening and the volumetric dilation of sandy soil during stressing. The model and the related parameters were then employed in the commercial software FLAC^2D to analyze the uplift behavior of various frictional anchors in sandy soil. Analysis results indicate that the friction stress along the fixed end of the anchor with a long fixed length exhibits progressive yielding under not only for a tension but also for a compression anchor. The progressive yielding behavior could be eliminated using a compound anchor because of the upward and downward transfer of load within the anchor shaft from the anchorage body. Therefore, a compound anchor can generate a higher anchorage capacity of all frictional anchors.

Abstract: In this experiment, nanoCaCO₃, nanoSiO₂, nanoTiO₂ and nanoZnO were chosen and added into waterborne camouflage coating respectively to make nanomaterial camouflage coatings. Both the surface tension and the contact angle of the coating (on steel plate and on concrete blocks) were measured by the OCA15+ video optics contact angle admeasuring apparatus; the nanomaterials influence on the interfacial properties of camouflage coating were studied based on its changing concentration. The experiment indicates that the relationship between the concentration of nanomaterial and the surface tension of the coating coincides with the Szyszkowski formula, but only when the concentration is relatively low; nanoSiO₂ has the best effect in improving the interfacial properties of camouflage coatings. It also proves that adding proper nanomaterial is an efficient way to improve the coatings durability.

Abstract: Support vector machines (SVM) and artificial neural network (ANN) were employed in modeling the flow stress of the AZ80 magnesium. The hot deformation behavior of extruded AZ80 magnesium was investigated by compression tests in the temperature 350-450 and strain rate range 0.01-50 s^-1. The maximum relative errors at different temperatures and different strain rates between experimental and predicted flow stresses by SVM and ANN were compared. The results show the SVM derives statistical models have better similar prediction ability to those of ANN, especially at high strain rate. This indicates that SVM can be used as an alternative modeling tool for high temperature rheological behavior studies.

Abstract: A nonvolatile memory thin-film transistor (MTFT) using an amorphous indium gallium zinc oxide (a-IGZO) semiconducting channel and a Ta₂O₅ gate insulator is proposed. The high-dielectric-constant material Ta₂O₅ was deposited by e-beaming and used for the charge storage layer, i.e., a metal-oxide-semiconductor (MOS) capacitor. We obtained memory windows (ΔV_th = 2 V) at 3-V gate voltage and realized reliable memory operations. Therefore, a-IGZO TFT with Ta₂O₅ can be employed in integrated high-performance nonvolatile memory devices for applications to transparent displays and flexible electronic devices.

Abstract: Porous silicon (PS) has the strong photoluminescence (PL) at room temperature and high specific surface. In this paper, we have fabricated the PS coated with silver nanoparticles as a substrate. The result shows that the substrate made in this way is stable for more than twenty days and the strong PL intensity of PS is around 584nm after immersed into solution of AgNO_3. The formation of SiAg bond was demonstrated to be responsible for the improvement of PL properties.

Abstract: The objective of this study is to examine the role of polymerizable and unpolymerizable pendant group of surfactant in clay dispersion in diallyl phthalate (DAP) matrix and evaluate the mechanical properties of resulting nanocomposites. Results of X-ray Diffraction (XRD) and high magnification Transmission Electron Microscopy (TEM) indicate an intercalated morphology for both types of nanocomposites, while low magnification TEM results show better dispersion of clay tactoids in the nanocomposite formulated with organclay containing polymerizable terminal pendant group. The mechanical properties of nanocomposites with organoclay loading of 1, 3, 5 and 7 wt%, respectively, were determined by performing flexural measurements. The testing results show that the nanocomposite formulated with organclay containing polymerizable terminal pendant group has better flexural properties than that formulated with organoclay containing unpolymerizable pendant group.

Abstract: Effect of the addition of α-Si₃N₄ on the nitridation of silicon powder was studied at 1550 and atmospheric pressure. Silicon powder of 2.2μm in size and 99.99% in purity was adopted as experimental materials, α-Si₃N₄ powder of 2.2μm in size and 99% in purity was used as diluent, and nitrogen of 99.9993% in purity was used as reaction gas. The morphologies and phase compositions of the products were analyzed by SEM and XRD respectively. The results show that the conversion of silicon is improved considerably by increasing the adding proportion of α-Si₃N₄ diluent. When the adding proportion of α-Si₃N₄ increases from 10% to 50%, the conversion of silicon powder increases from 38% to 92.55%. The content of β-Si₃N₄ in product decreases, after an initial increase, with the adding proportion of α-Si₃N₄ increases, and it reaches the peak point when the adding proportion of α-Si₃N₄ was 30%. The sinterability of silicon nitride decreases as the content of β phase increases, so the adding proportion of α-Si₃N₄ should be kept away from 30%.

Abstract: The properties of PLA spun yarn was investigated comparing with cotton and PET spun yarns of the same linear density. The PLA/cotton blended fabric (50/50) was prepared and the fabric properties were analyzed in comparison with the 100% PLA and cotton fabrics. It was found that in the PLA/cotton blended fabric, cotton was the component that imparted moisture absorption, strength and drapeability to the fabric, while, PLA provided dimensional stability to the blend. Investigation of the effect of the pretreatment and dyeing processes found that the bleaching process for cotton with H₂O₂ under alkaline conditions caused a significant strength loss to the PLA fabric. The dyeing processes exhibited a slightly negative effect on the fabric strength. Meanwhile, the strength of cotton fabric was much less affected by the pretreatment and dyeing processes used. The fabric hand properties, viz. stiffness and drapeability of PLA and cotton fabrics were also influenced by the pretreatment and dyeing processes.

Abstract: In this paper, we report a simple strategy for fabricating mesoporous magnesium borate (2MgO·B₂O₃) microspheres. We employed sodium dodecyl sulfate (SDS) in one system, as a template for the controlled growth of mesoporous 2MgO·B₂O₃ microspheres. The products were characterized by XRD, SEM, TEM, EDS, N₂ sorption and FT-IR. SEM and TEM observations indicate magnesium borate products are composed of a large number of hollow microspheres, with diameters of 1.0~1.5 μm, which are in fact built from fibers with lengths of 100~150 nm. The N₂ sorption results show that the products have meso-structures. The average pore diameter is 27 nm. The BET surface area is about 53.03 m²/g, and the pore volume is 0.37 m³/g. It was found that SDS plays a key role for the formation of mesoporous structure. A possible mechanism was proposed to interpret the formation of the mesoporous structure. The mesopores will endow the hierarchical microspheres with novel application potentials.