Advanced Materials Research Vols. 634-638

Abstract: Macromolecule modification activator was prepared using prepolymer of HTBN end capped by HDI biuret (N-75). Then the ABS/PA6 co-blend polymer was prepared by anionic polymerization with putting ABS resin into molten caprolactam monomer at the temperature of 160-180 °C and the sodium hydroxide being used as activator. Compared with PA6， the copolymer alloy shows obviously low water absorption and slightly reducing mechanical property after absorption， while the loss of mechanical property is lower. The SEM analysis reveals that the reaction insitu compatibilization reduces the interfacial tension between PA6 and ABS and makes the ABS grain smaller and more uniform dispersion in PA6.

Abstract: Porous TiC-TiB₂-NiAl composites have been prepared through self-propagating high-temperature synthesis (SHS) of 3Ti + B₄C + x(Ni+Al) → TiC + 2TiB₂ + xNiAl using Ni, Al, Ti, B₄C powders as raw materials. The effects of Ni and Al content on phase constitution and pore structure of the obtained porous TiC-TiB₂-NiAl composites have been investigated. XRD results show that the final composites of Ti+B₄C+Ni+Al powders consist of TiC, TiB₂ and NiAl, while only TiC and TiB₂ are observed without using Ni+Al powders in the reaction system. NiAl additives play a significant role in controlling reaction behavior and constituents of the final products. TiC, TiB₂ and NiAl are homogenously distributed in porous TiC-TiB₂-NiAl composites, and TiC shows spherical shape, TiB₂ exhibits hexagon or long strip shape while NiAl shows the irregular shape distributed between TiB₂ and TiC particles. The prepared TiC-TiB₂-NiAl composites contain a large amount of pores with the aperture concentrating between 20-80μm and the porosity was about 35%, NiAl additives make the pores distributed uniformly in the matrix. The more NiAl additives, the more obvious of melting trace on the matrix skeleton, some spherical particles adhering on pore wall gradually submerge in matrix and combine with it closely. The NiAl additives increase the compressive strength of TiC-TiB₂ and for TiC-TiB₂-NiAl composites, the fracture mode of TiB₂ and TiC is brittle fracture, while NiAl mainly occur transgranular fracture.

Abstract: A method of determination of Y , La ,Pr , Sm , Ce ,Gd and Nd rare-earth elements in Titanium matrix composite by inductively coupled plasma atomic emission spectrometry (ICP-AES ) was study. The experiment of sample dissolution，selection of analysis lines，the effect of matrix and coexist elements on the determination , instrument parameters of the analysis results were carried out. The recovery rate of this method was found in the ranges 98% to 105%, the RSD were less than 4%. The method is simple, rapid and accurate.

Abstract: In this paper, it can be seen that the optimum mixture ratio of graphite to other contents (graphite: HNO3: H2O2: KMnO4 ) is 1.0(g):6(ml): (2.0ml):(0.2g), which obtained the best expansion volume. The graphite sheets within EG were nanoscales, rare earth nanoparticles were dispersed between holes of expandable graphite sheets. Evidently, the graphite nanosheets wrapped in the rare earth particles can be observed. It is clearly that the rare earth particles within EG were nanoscales. In addition, rare earth particles on expandable graphite were nanoscales, and the EG/CeO2 composite obtained by this process is a product with amorphous alloy structure.

Abstract: In this paper, a research approaching on nano-TiO2 particles modified fabric functional enhancement is reported. The morphologies of the nano particles existing on_{Subscript text} the fabric surface were examined by scanning electron microscopy (SEM), which showed that the particle size is less than 100nm and almost no coacervation, and then water-repellent and oil-repellent performance of the modified fabric was measured by the contact angle method, and found they had the most desired water and oil release behaviors. In addition, the modified fabric showed excellent antibacterial effects according to FZ/T73023-2006 antibacterial standard, and the antibacterial efficiency was above 95%. Meanwhile, good durability of functional fabrics also observed which could endure 20 times washing at least.

Abstract: The precipitation hardened steel 10Ni3MnCuAl after solution heat treatment and aging at 510 °C is investigated by three dimensional atom probe (3DAP). The results show that the Ni, Mn, Al and Cu distribute uniformly in the steel after solution heat treatment, but they form multicomponent precipitates after aging and cause the hardness increase. The concentration ratio between Ni and Al in multicomponent precipitates is roughly 1, while the concentration of Fe decreases, and the distance between concentration peak of Cu and those of Ni and Al becomes wider with the aging time, which is related to the precipitation character of Cu in α-ferrite.

Abstract: Boron nitride nanotubes attract wide interest because of their unique structures as well as super properties. The structures, properties, synthetic methods and application studies are particularly summarized. Since they were discovered, additionally, the prospects for future research and application are proposed. In this paper, advances in researches on Boron Nitride (BN) nanotubes are reviewed, and some of technologies for preparation of BN nanotubes are described. The tip structures of BN nanotubes produced by different technologies are compared and discussed.

Abstract: In droplet-based biochemical microreactors, the reaction rate, the content of chemicals, and the composition of final products have to be involved with the individual droplet size. The common method to determine droplet size is by the straightforward measuring of the 2D images recorded by a high speed camera from the top view, regardless of the real droplet shapes. However, this method is not always true due to the droplet deformation by the combined effects of viscous drag and channel confinements. Here we report that the real droplet could be spherical, hemispherical or flattend disk, leading to different droplet sizes even for the same 2D profiles from the top view. The new findings of this paper are crucial to avoid the improper estimation of droplet size for the droplet-based microfluidic applications.

Abstract: A citric acid anionic surfactant has been applied for nano manganese ferrite (MnFeO3) fabrication using sol gel method. The calcinations have been varied for 300, 600 and 800oC. The UVDR (UV-Vis Diffused Reflectance) analysis shows a high absorptive band gap after 400 nm for the 600oC calcinated MnFeO3. The DTA (Differential Thermal Analysis) profiles exhibit remarkably trapped volatile matters (H2O, CO2, and NO2) in the fabricated MnFeO3 under sol gel heat treatment at 100oC and the peaks disappeared as the calcination increased to 600oC. As the temperature elevated from 100 to 300oC, the absorption peaks of volatile components are disappeared as demonstrated clearly by the FTIR (Fourier Transform Infrared) spectra of the fabricated material, which 3393 cm-1 corresponded to OH group, 1624 cm-1 to CO group, and 1384 cm-1 to NO group. The XRD (X-Ray Diffraction) spectra show clearly the alteration process from amorphous to crystalline structure as the calcinations increased from 300 to 600oC. In addition, the TEM (Transmission Electron Microscope) analysis exhibits parts of the fabricated MnFeO3 found in cubic nano size of 15-40 nm under interested calcinations and the result is in agreement with that obtained by XRD investigation.

Abstract: Iron tetrapyrazinoporphyrazine (FePTpz) and cobalt tetrapyrazinoporphyrazines (CoPTpz) supported on multiwalled carbon nanotubes (MWCNTs) are prepared by solid phase synthesis method. The products are characterized by scanning and transmission electron microscopy. The electrocatalytic activity of the obtained MWCNTs-supported FePTpz and CoPTpz assemblies (MPTpz/MWCNTs) is measured by cyclic voltammetry and rotating disk electrode techniques in an oxygen-saturated 0.1M KOH. The results show that MPTpz/MWCNTs are more efficient than reference MPTpz. FePTpz/MWCNTs are more efficient for O2 reduction than CoPTpz/MWCNTs, both of FePTpz/MWCNTs and CoPTpz/MWCNTs exhibit a one-step, four-electron pathway for ORR.