Advanced Materials Research Vol. 645

Abstract: In order to promote NaHCO₃ extinguishing powder farther application in explosion extinguishing fire field, Mechanical behavior of the loose and pre-compression NaHCO₃ powder was studied by MTS and SHPB experimental apparatus. The results showed that the loose and pre-compression powder were viscous material. With pre-pressure increased, the density and yield strength of pre-compression power increased, but th e porosity decreased. With strain rate increased, the yield strength of pre-compression increased.

Abstract: Produced in Ji’an of Jilin Province, An’lv jade is named after Lvshui River in that region. The research shows that the main mineral composition of An’lv jade is lizardite and the type and content of the chemical constituent has great influence on the color of jade. Due to the “chromophore” of Fe, the jade is mainly in green, varying from light yellow green to dark green and even to blackish green along with the increment of content. However, some “non-chromophores” also affect depth (intensity) of the color of jade, for example, the color of jade becomes light and its transparency becomes better along with the increment of the content of Si, Al, Mg, OH.

Abstract: Nickel–zinc ferrites with chemical formula Ni1-xZnxFe2O4 (x = 0, 0.2, 0.4, 0.6, 0.8 and 1.0) were prepared by oxalate co-precipitation method. The dielectric constant (ε') dielectric loss (tanδ) and AC conductivity (σac) of all the samples were determined at room temperature in the frequency range 20Hz -1MHz. The dielectric constant and dielectric loss are much smaller than those for samples prepared by ceramic method. The dielectric behaviour is attributed to the Maxwell–Wagner type interfacial polarization. AC conductivity of all the samples lies in the range 1.20×10-8 to 54.7×10-8 Ω-1cm-1. Low dielectric loss and high resistivity suggest the suitability of these ferrites for high frequency applications.

Abstract: Reversible photoisomerization between the cis and trans isomer of [Ru(OAc)(2mqn)2NO] (H2mqn=2-methyl-8-quinolinol) was studied quantitatively, using 1H Nuclear magnetic resonance (NMR) spectra. The kinetic study showed that the photoisomerization from trans to cis isomer was first-order and the rate constant (k) is 0.014 (min-1) at 420 nm, 0.0034 (min-1) at 550 nm, respectively. The main absorption band in UV-Vis region for cis and trans isomer was observed from 300 nm to 550 nm, the electronic structure of these compounds was performed with DFT (Density functional theory) calculation and was discussed based on HOMO–LUMO analyses. The study provide detail information to design advance optoelectronic materials based on nitrosylruthenium(II) complexes.

Abstract: Nitrogen and Phosphorus co-doped (N+P)- zinc oxide (ZnO) films were RF sputtered on corning glass substrates at 350 °C and comparatively studied with undoped, N-, and P- doped ZnO. X-ray diffraction spectra confirmed that the ZnO structure with a preferred orientation along direction. Scanning electron microscope analysis showed different microstructure for the N+P co-doping, and thus probably confirming the co-existence of both the dopants. X-ray photoelectron spectroscopy spectra revealed that the chemical composition in N+P co-doped ZnO are different from that found in undoped, N-, and P- doped ZnO. The atomic ratio of N and P in N+P co-doped ZnO is higher than that in single N or P doped ZnO. One broad ZnO emission peak around 420 nm is observed in photoluminescence spectra. The relative intensity of the strongest peak obtained from co-doped ZnO films is about twice than the P- doped and thrice than the pure and N- doped films.

Abstract: Micromachine service life is often shortened by excessive adhesion and friction forces arising during fabrication or operation. SiC film is a possible choice for MEMS surfaces because of its favorable friction and wear properties. In this study, biocompatibility SAMs film (OTS), in advance, was used to decrease the adhesion force and extend the lifetime of MEMS devices for the different SiC topography. Experimental results show that OTS can increase the contact angle of SiC surfaces for the different roughness values and roughness directions. Small roughness value of OTS surfaces has a smaller friction coefficient than that of large roughness value surfaces.

Abstract: A facile approach for prepar ing stearoyl diethanolamide was reported. The as-synthesized product was further applied for the protection of car bon steel from corrosion solution. On the basis of orthogonal experiments, optimal reaction conditions were investigated. The results show that the yield rate can be up to 84.6% under a condition of molar ratio of stear ic acid to ethylenediamine is 1:1.7, the reaction time and temperature are 4 h a nd 175 °C, respectively. The optimal concentration and potential corrosion-inhibiting mechanism were al so investigated by using scanning electronic microscopy, weight loss and electrochemical analysis. The presented synthesis route is facile which enable it to be promisingly applied for production widely. Furthermore, the excellent corrosion-inhibiting properties of st earoyl diethanolamide also indicate that it can be a fascinating candidate for protecting steels from corrosion in oil exploration and transportation.

Abstract: Defects occurring in constructi ons go hand in hand with the need to prevent such defects. For this reason, there is a need to develop new preservative products. One of the availa ble alternatives for protecting floor surfaces is the use of epoxy screed s. This article deals with the development of a new epoxy screed that would utilize secondary raw materials as fi llers. The use of secondary raw materials is a very current issue, as their use cont ributes to resolving problems associated with their disposal.

Abstract: We present our findings of increased fracture toughness in high performance Sm₂Co₁₇-type magnet. The new Sm(Co _0.65 Fe _0.24 Cu _0.08 Zr _0.03)7.6magnet exhibits remanence of 11.13 kGs, maximum energy of 30.2 MGOe. This magnet shows not only a superhigh fracture toughness of 5.56 MPa m ^1/2 but also distinguished yielding combined with an enhanced plastic plateau of 30 % to failure. It has been found that debonding, crack deflection, crac k branching and bridging are the major toughening mechanisms for the observed high toughness and long yield plateau. Long and straight screw dislocations observed in Sm rich precipitates accelerate the debonding of Sm rich grains.

Abstract: Single electron transfer living radical polymerization (SET-LRP) has developed to be a robust tool for the construction of well-designed polymers. This paper reports the influence of one cheaper initiator on the SET-LRP process. The SET-LRP of methyl methacrylate (MMA) initiated with benzyl chloride and catalyzed by Cu(0)/PMDETA at 25°C in methanol is described. The polymerization kinetics was recorded. The reactions followed first-order kinetic in monomer consumption and the molecular weights increased linearly with conversion while retaining narrow molecular weight distribution. Therefore, it is plausible that SET-LRP of MMA initiated with benzyl chloride process to yield well defined macromolecules.