FORMATION AND FLOW OF GAS BUBBLES IN A PRESSURIZED BUBBLE COLUMN WITH A SINGLE ORIFICE OR NOZZLE GAS DISTRIBUTOR

The characteristics of gas bubbles in a 5 cm diameter bubble column equipped with a single orifice of 1,3 or 5 mm diameter were investigated under system pressure of 0.1-15 MPa. The formation of gas bubbles was strongly affected by the system pressure. Under high pressures a dispersed gas jet was formed at gas velocities where spherical gas bubbles would have been formed at atmospheric pressure. The critical gas velocity between the bubbling regime and the jetting regime was correlated with the liquid phase Weber number and the gas phase Reynolds number based on the gas velocity at the orifice. Bubble size and gas holdup in the main part of the bubble column were also affected by the bubble formation pattern at the distributor     

Polymerization of propylene over metal oxides-supported TiCl3 catalysts

Summary Several metal oxides-supported TiCl₃ catalysts were prepared and propylene polymerization was conducted over them without cocatalysts. It was found that isotactic polymerization of propylene took place effectively over them.     

Polymerization of propylene over titanium exchanged Y-zeolite

Summary It was found that isotactic polymerization of propylene took place over titanium ion-exchanged Y-zeolite without organometallic compounds. The results obtained have led to the conclusions that Ti⁴⁺ species as well as Ti³⁺ species are active for the polymerization and that neither Ti-alkyl bonds nor Cl ligands are necessarily essential for polymerization of propylene.     

Comparative study of lipogenic enzymes in several vertebrates

The liver lipogenic enzymes are compared among rats, chickens, frogs and fish. Although the apparent Km values of glucose-6-phosphate dehydrogenase for glucose-6-phosphate are not much different among all the species, those of malic enzyme for malate are much higher in chickens and fish than in rats and frogs. Glucose-6-phosphate dehydrogenase showed very high activities compared with malic enzyme in fish liver, and malic enzyme showed high activities in chicken liver. Although the apparent Km values of acetyl-CoA carboxylase and fatty acid synthetase for substrates are in the same range among all the animals, the activity of acetyl-CoA carboxylase seems to be extremely low in fish and frog livers, and that of fatty acid synthetase is low in frog livers only. In addition, the apparent Km values of α-glycerophosphate acyltransferase of fish liver are very high, and the enzyme activity appears to be extremely low compared to the others. Therefore, the enzymes at the first steps of both fatty acid and glycerolipid syntheses of poikilothermos animals appear to be very low. On the other hand, the Ouchterlony double-diffusion patterns showed that the lipogenic enzymes of chickens, frogs and fish are immunologically different from those of rats, with the exception of acetyl-CoA carboxylase in chickens. Therefore, it is suggested that the fatty acid and glycerolipid forming systems of poikilothermos animals are quite different from those of homoiothermos and the lipogenesis is very low in poikilothermos.     

Prooxidant effects of inorganic chromium compounds in the autoxidation of methyl linoleate

The prooxidant property of inorganic chromium compounds was determined in methyl linoleate free from natural antioxidants and metals. Prooxidant properties of inorganic chromium compounds appeared in order of sodium chromate > chromium (VI)-oxide > chromium chloride > potassium chromate > chromium (III)-oxide > potassium dichomate. In comparison with the control, additions of chromium compounds induced different amounts of autoxidation products derived from methyl linoleate, such as small amounts of hydroperoxides and conjugated dienes and large amounts of hydroxy groups,α,β,γ,δ-unsaturated carbonyls, isolatedtrans double bonds, polymers, and free radicals. From these analytical data, the catalysis of chromium compounds in the autoxidation of methyl linoleate seemed to be based on their abilities of abstracting a hydrogen from methyl linoleate and decomposing hydroperoxides derived from the autoxidation of methyl linoleate.     

Development of a high‐resolution RGBW flexible display using a white organic light‐emitting diode with microcavity structure and that of a side‐roll touch panel

In this study, white organic electroluminescent devices with microcavity structures were developed. A flexible high‐resolution active‐matrix organic light‐emitting diode display with low power consumption using red, green, blue, and white sub‐pixels formed by a color‐filter method was fabricated. In addition, a side‐roll touch display was developed in combination with a capacitive flexible touch screen.     

Control of molecular weight distribution of isotactic polypropylene obtained by a MgCl2-supported TiCl4 catalyst

It is of great importance in propene polymerization to control molecular weight and molecular weight distribution as well as isotacticity. Propene polymerization was carried out with an isospecific MgCl₂/TiCl₄-Cp₂TiMe₂ catalyst in the presence of various kinds of external Lewis bases. It was found that the molecular weight distribution of the isotactic polymer could be controlled while retaining high activity, high isospecificity and high molecular weight only by changing the kind and/or amount of the Lewis bases. © 1997 Elsevier Science Ltd.     

Polymeric phosphonium salts as a novel class of cationic biocides. VII. Synthesis and antibacterial activity of polymeric phosphonium salts and their model compounds containing long alkyl chains

Various polymeric phosphonium salts containing long alkyl chains (C₁₀? C₁₈) and their corresponding model compounds were prepared, which possess the same hydrophobic structure as that of the common disinfectants (quaternary ammonium salts), and their antibacterial activities were evaluated by means of the viable cell counting method against Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative). The polymer with the decyl group exhibited a higher activity than that of the corresponding model compound, particularly against the Gram-positive strain. Furthermore, antibacterial activity of the polymers was found to decrease as the chain length increased. In contrast with the polymers, the antibacterial activity of the corresponding model compounds increased as hydrophobicity of the substituents increased. The antibacterial activity was strongly dependent on the structure, particularly on the length of the alkyl chain. © 1994 John Wiley & Sons, Inc.     

Phase separation behavior and morphology development of phenolic resin/PMMA/hexamethylenetetrarnine blends

Summary In order to obtain materials with nanopores which will be applicable for many fields, the structures of the cured blends of phenolic resin (PhN), poly(methyl methacrylate) (PMMA) and curing agent were studied. After PMMA was extracted from cured blends, the structures of cured phenolic resins were observed with SEM. As a results, it was found that nanosized continuous pore structures were formed in extremely wide composition region if curing temperature was high.     

Liquid crystalline side-chain polysiloxanes containing mesogenic groups attached by esterification

Summary Liquid crystalline side-chain polysiloxanes were prepared without metal complex catalyst. Mesogenic groups such as cholesteryl, 4-cyano-4-biphenyl and 4-methoxy-4-biphenyl group were introduced into polysiloxane by esterification and from DSC measurements they were compatible with other liquid crystalline polysiloxanes reported previously.