Silica-supported cobalt catalysts for the selective reduction of nitrogen monoxide with propene

Catalytic behavior of silica-supported transition metals for NO reduction with propene in the presence of oxygen was investigated. While both silica and cobalt oxides did not show any activity for the selective NO reduction, impregnated CoO/SiO₂ prepared from cobalt acetate showed good activity although the preparation conditions had significant effect on the activity. It was suggested that highly dispersed surface Co²⁺ ions on silica are responsible for the catalytic activity.     

Copolymerization of phenylacetylene with various acetylenes by W- and Mo-based catalysts

In the copolymerization of phenylacetylene with various acetylenes catalysed by WCl₆·Ph₄Sn, the relative reactivity of monomer decreased with increasing steric effect of monomer, e.g. HC  Cn-Bu, HC  Cn-Hex > HC  CPh, HC  Cs-Bu > HC  Ct-Bu, MeCCPh, CICCPh. While 1-chloro-2-phenylacetylene (a disubstituted acetylene) showed high reactivity in the homopolymerization by Mobased catalysts, the reactivity was remarkably depressed in the presence of phenylacetylene as comonomer. Based on these results, the relative reactivity of the acetylenic monomers in copolymerization was explained in terms of competitive coordination of monomers to the propagating end.     

Synthesis of Super-Microporous Aluminosilicate Having Excellent Water Vapor Adsorption Property as an Adsorbent for an Adsorption Heat-Pump

The synthesis of super-microporous aluminosilicate with a pore diameter of 14.6 Å has been achieved, by means of synthesis under specified conditions with a skeletal material comprising TMOS and a small quantity of sodium aluminate, and a conventional alkyl-trimethylammonium halide (C₁₀TMABr) as a template. This super-microporous aluminosilicate has an adsorption capacity of 0.2 ml/g at a relative water vapor pressure of 0.2, and thus is promising as an adsorbent for an adsorption heat-pump.     

Effects of growth temperature on the fatty acid composition of the free-living nematodeCaenorhabditis elegans

The effects of growth temperature on the fatty acid compositions of the phosphatidylcholine (PC), phosphatidylethanolamine (PE), and total lipid (TL) fractions of the free-living nematodeCaenorhabditis elegans were investigated. A reduction in growth temperature from 25 to 15°C caused the proportions of eicosapentaenoic acid (20∶5n-3) to increase from 23.6 to 32.5% in the PC, from 7.4 to 10.8% in the PE, and from 12.9 to 19.9% in the TL fractions. Conversely, the levels of dihomo-γ-linolenic acid (20∶3n-6) and arachidonic acid (20∶4n-6) in these phospholipid fractions and the TL fraction both decreased with decreasing growth temperature. Analysis of the positional distribution of fatty acids in the PC fraction revealed that the change in the composition of C₂₀ polyunsaturated fatty acid was obvious in positionsn-2. Lowering the growth temperature induced an increase in the level of the diacyl subclass of PE from 58% at 25°C to 71% at 15°C, with a concomitant decrease in the levels of the alkylacyl and alkenylacyl subclass of PE ofC. elegans. These changes observed in the phospholipids ofC. elegans might be one mechanism for adaptation to low temperature. Lipids 31, 1173–1178 (1996).     

Shear-rate dependence of first normal stress difference of poly(isoprene-b-styrene) in solution near the order-disorder transition temperature

Viscoelastic properties of poly(isoprene-b-styrene) in dioctylphthalate under steady shear flow were measured near the order—disorder transition temperature. In ordered states, first normal stress difference N₁ is proportional to shear rate at low region, but becomes proportional to at the high region, similar to the N₁ behaviour of polymer blends undergoing shear-induced homogenization. Because the existence of microdomains was confirmed at the high region by the flow birefringence method, it is concluded that the above N₁ behaviour is not caused by shear-induced homogenization, but is probably caused by the shear-induced alignment of the microdomain structure.     

Effect of Fe-Zn alloy layer on the corrosion resistance of galvanized steel in chloride containing environments

In this study, the effect of Fe-Zn alloy layer that is formed during galvanizing process on the corrosion behavior of galvanized steel has been investigated. The galvanostatic dissolution of galvanized steel was carried out in 0.5 M NaCl solution to obtain the Fe-Zn alloy layer on the base steel. The alloy layer was characterized to be composed of FeZn₁₃, FeZn₇ and Fe₃Zn₁₀ intermetallic phases, which constitute the zeta, delta1 and gamma layers of galvanized steel, respectively. It was observed that the alloy layer has similar cathodic polarization behavior but different anodic polarization behavior compared to galvanized steel. The anodic current plateau of alloy layer was up to 100 times lower than that of galvanized coating. Corrosion test performed in wet-dry cyclic condition has shown that the alloy layer has lower corrosion rate as compared to galvanized steel. From the results of corrosion test of alloy layer and base steel, it was concluded that Zn²⁺ has positive effect on the protectiveness of the zinc corrosion products. The measurement of surface potential over the alloy/steel galvanic couple has confirmed the galvanic ability of alloy layer to protect both the alloy layer itself and the base iron during initial stage of atmospheric corrosion.     

低气压等离子喷涂TiO2涂层结构的研究

本研究分析了在低气压等离子喷涂条件下,TiO_2涂层的结构受等离子弧喷涂过程中氧分解量所影响。氧分解量很大程度上依赖于离子气中氢流量的大小,此外喷涂室压力也有一定影响。而等离子弧功率和喷涂距离对TiO_2涂层的氧分解量没有多大影响。在离子气中氢流量不变的条件下,涂层中Ti_3O_5量随喷涂室压力(从100×133.322Pa至400×133.322Pa)增加而增加。     

Swarm robotic network using Lévy flight in target detection problem

One approach in swarm robotics is homogeneous system which is embedded with sensing, computing, mobile and communication components. In this study, a target detection problem, which is one of navigation problems, was employed. Once a robot detects a target, robots immediately communicate with a base station via intermediate relay robots due to the multi-hop transmission of wireless communication. Therefore, this control task is completed with connectivity of the network. In a target detection problem, we must improve the performance of exploration as well as connectivity of the network. This study investigates the performances of the two types of random walk algorithm in navigation while loosely ensuring connectivity of the robotic network based on our previous study.     

Control of secondary flow in concentrically traveling flow on centrifugal microfluidics

This paper reports a fundamental study of the stripe laminar flow pattern on a centrifugal microfluidic device with the goal of realizing a sedimentation-based, continuous mode particle separation technique. Microfluidic channels were designed with a concentrically integrated microchannel, and the patterning of the flow in the channel was investigated. A significant secondary flow was observed as a preliminary result. We conclude that the origin of this secondary flow was not the Dean force, because it was observed in a straight microchannel, but was not observed in curved channel during the spinning of the system at rest. The transition of the pattern was investigated using a simulation and experiment, and the flow pattern’s dependence on the rotational speed was determined, which suggested that the origin of the secondary flow was the Coriolis force. The significance of the secondary flow was controlled by adjusting the rotational speed of the disk, and the flow rate and laminar flow patterns were controlled by the stripe flow pattern.