Influence of the introduction of flexible alkyl chains on the thermal behavior and mechanical properties of mesogenic epoxy thermosets

A mesogenic epoxy resin (DGETAM) was cured with a series of curing agents having different lengths of long alkyl chain (nBAB, n = 4, 8, 12). Properties of the curings were compared with those of the DGEBA cured with the same curing agents revealing the achievement of a balance between certain levels of thermal properties and excellent mechanical properties. Moreover, some curing systems were prepared with twin mesogenic type epoxy resins (DGEnMA, n = 4, 6, 8, 10, 12) having different lengths of alkyl chain as a flexible spacer and the same curing agents (n′BABs). Combinations of the same concentrations of chemical structures in the basic units of the network structure were applied, and the thermal and mechanical properties of their curing systems were investigated. The fracture energy of each system increased considerably with the increase of the alkyl chain length that adjoins the two mesogenic groups in the epoxy resins. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44244.     

Growth of High-Quality Pb((Zn1/3Nb2/3)0.91Ti0.09)O3 Single Crystals by Excess ZnO Addition

A high-quality single crystal of Pb((Zn_1/3Nb_2/3)_0.91Ti_0.09)O₃ (PZNT 91/9), 40 mm in diameter and 20 mm in length, was successfully grown using the solution Bridgman method with a slight excess amount of ZnO. High-quality wafers were sliced from the light-brown single crystal. No PbO inclusions or opaque areas were observed in the transparent wafers. An array probe for echocardiography was constructed with the single-crystal wafer, and its superior performance was demonstrated.     

The effect of salinity on nitrite accumulation in a down‐flow hanging sponge reactor

BACKGROUND: In this study, the inductive effect of salinity on nitrite accumulation in a down‐flow hanging sponge (DHS) reactor, developed as a novel and cost‐effective wastewater treatment process, was evaluated by conducting a long‐term continuous experiment lasting more than 1400 days. RESULTS: The influent salinity was controlled by adding NaCl at concentrations ranging from 0 to 25 g Cl^? L^?1. The effluent nitrite increased with increases in salinity, i.e. the fraction of nitrite to total nitrogen in the effluent increased from 1.6% at 0 g Cl^? L^?1 to 87.6% at 25 g Cl^? L^?1. Fluorescence in situ hybridization (FISH) analysis revealed that as salinity increased, the nitrifying bacterial community in the DHS changed markedly at the species level. In particular, the dominant nitrite‐oxidizing bacteria changed from Nitrospira‐sublineage I at 0 g Cl^? L^?1 to Nitrobacter spp. at 15 g Cl^? L^?1. At 25 g Cl^? L^?1, no nitrite‐oxidizing bacteria were detected. CONCLUSION: Our findings suggest that the DHS reactor is suitable for cost‐effective nitrite production processes and that salinity control using NaCl is an effective method for inducing nitrite accumulation. Copyright © 2012 Society of Chemical Industry     

Enantio-differentiating hydrogenation of prochiral ketones over modified nickel

This article reviews the enantio-differentiating hydrogenation of prochiral ketones over a asymmetrically modified catalyst, focusing on the hydrogenation of simple prochiral alkanones. The parameters affecting catalytic activity and enantiodifferentiating ability are considerable in number, and each parameter should be optimized in order to attain a highperformance enantio-differentiating catalyst. Optimization of the parameters and the mode of enantio-differentiation are discussed and compared with the enantio-differentiating hydrogenation of β-ketoesters.     

Enantioselective addition Of diketene to aldehydes promoted by chiral schiff base—titanium alkoxide complex. Application to asymmetric synthesis of potential inhibitors of HMG coenzyme reductase

Highly enantioselective addition of diketene to aldehydes was achieved by using novel Schiff base—titanium alkoxide complexes. Up to 92% ee of 5-hydroxy-3-oxoesters was obtained. This procedure provides an efficient method for the asymmetric synthesis of potential inhibitors of HMG coenzyme reductase.     

RESEARCH ON REFRACTORY SUPERALLOYS IN THE HTM 21 PROJECT

It was proposed that a new class of alloys based on platinum group metals (PGMs) were calle drefractory superalloys. These refractory superalloys have an fcc and L12 coherent two-phase structure (similar to that of Ni-based superalloys), high melting temperatures and good potential as structural materials used at temperatures up to 1800℃. Our recent results on the microstructure evolution, deformation and fracture behavior of some of these refracotry superaUoys, especial lr- and Rh-base refractory superalloys were reported.     

Demulsification of oil-in-water emulsion under freezing conditions: Effect of crystal structure modifier

The demulsification of oil-in-water (O/W) emulsions under freezing conditions is connected to fat crystallization in the oil droplet. Therefore, demulsification can be prevented by the use of oil with a low melting point, and also by lowering the O/W ratio. However, an oil with a low melting point, such as sunflower, is rather expensive, and the O/W ratio has a significant effect on the texture of emulsions. We searched for an oil that is suitable for the production of a freeze-stable emulsion and found that soybean oil has unique characteristics. Normally, emulsions are more unstable at lower temperatures; soybean oil emulsion is unstable at −10°C and stable at −20°C. This unique characteristic results from the following two reasons. First, the solid fat content of soybean oil is almost the same at −10 and −20°C. Second, small crystals form a larger network over a period of time, and the higher temperature promotes faster restructuring. This structure formation was microscopically observed with the use of a thermostated stage. Structure formation was suppressed with the addition of a crystal structure modifier, polyglycerol fatty acid full ester, which also suppressed coalescence.     

Formation Mechanism and Synthesis of Apatite-Type Structure Ba2+xLa8−x(SiO4)6O2−δ

The formation process of Ba₂La₈(SiO₄)₆O₂ was clarified using thermogravimetry–differential thermal analysis (TG-DTA) and a high-temperature powder X-ray diffraction (HT-XRD) method. Phase changes identified from the HT-XRD data surprisingly corresponded to the weight loss and/or endothermic peaks observed in the TG-DTA curves. Raw material with the composition Ba₂La₈(SiO₄)₆O₂ was completely reacted at 1400°C and produced only an apatite-type compound without a secondary phase. Moreover, the synthesis of Ba_{2+ x} La_{8− x} (SiO₄)₆O_2−δ crystals with x = 0–2 was attempted using a solid-state reaction.