Effect of bound water on piezoelectric,dielectric, and elastic properties of wood

The interaction of water with wood, such as bamboo and cedar, is investigated by measuring their complex piezoelectric, dielectric, and elastic constants between -150 and 150°C at 10 Hz. Bamboo and cedar are found to have two hydration-dependent elastic loss peaks; one is observed at about -100°C and the other at about -40°C. The former loss peak is due to the adsorbed water in the hydration range between 0 and 4% moisture content (MC) and the latter to the adsorbed water above 4% MC. These two types of water are considered bound on different sites in the regions around crystalline cellulose, where molecules of one type associate with each other and molecules of the other are unassociated. We consider that the piezoelectric polarization of wood is attributed to the rotation of hydroxyl groups in the crystal lattice of cellulose. The piezoelectric constants are observed to decrease but the elastic and dielectric constants to increase with increasing hydration. The effect of adsorbed water on elastic losses in bamboo and cedar are found to be similar to that in collagenous substances.     

Phosphate inhibition on thermophilic acetoclastic methanogens: a warning.

The inhibitory effect of phosphate on acetoclastic-methanogens was investigated for three different thermophilic (55 degrees C) anaerobic consortia. When 70 mM of phosphate was tested, acetoclastic methanogens was completely inhibited in "Eerbeek" sludge which is dominated by Methanosaeta-like methanogens. For the "Hoogezand" sludge the specific methanogenic activity dropped by 79%, indicating that any of the acetate-consuming methanogens present in the sludge was more resistant to the phosphate applied. The results demonstrated that the inhibitory effect of phosphate may affect both methane production rate and final methane concentration and might also be time dependent. This study indicates that the degree of inhibition is species-dependent, and even more resistant species may be affected during long-term experiments. Such inhibition is a matter of concern for researchers since misleading conclusions might be taken from growth and specific methanogenic activity tests when considerable concentrations of phosphate buffer are used and no interference is expected.     

Carbonization of aromatic hydrocarbons—V: Microscopic features of carbons obtained by the aid of catalysts

Microscopic observation of carbons obtained from pure aromatic hydrocarbons by the aid of carbonization catalysts was carried out to clarify the microstructure of these carbons of different features. Reflected polarized-light microscopy distinguished needle, mosaic and isotropic cokes, former two of which were produced with aluminum chloride and the last with potassium. High resolution microscopy revealed that these carbons calcined at 1250° had different degree of layered structure, corresponding to the crystallographic parameters of these samples graphitized at 2500°C. The reasons for the carbons produced with potassium to be non-graphitizable are discussed from the macro- and micro-features of the carbons.     

Ohmic contacts to Si-implanted InP

Ohmic contacts to Si-implanted, n⁺ layers on semi-insulating InP are investigated on the basis of the transmission line model. It is found that Au/Ni/AuGeNi/InP system shows a good ohmic behaviour with the specific contact resistance $\text{ρ}{}_{\mathrm{c}}\text{of}\text{2 × 10}{}^{\mathrm{?5}}\text{Ω}\text{cm}{}^2$ and the minimum contact resistance $\text{Z}{}_{\mathrm{c}}\text{of}\text{～ 2 × 10}{}^{\mathrm{?3}}\text{Ω}\text{cm}$ for a Si-dose higher than 2 × 10¹⁴ cm^?2 at 100 or 200 keV. The results indicate that, in the FET fabrication, at least 120 μm in length is necessary in order to obtain source and drain electrodes with the minimized resistance.     

Abnormal activation of lipoprotein lipase by non-equilibrating apoC-II: further evidence for the presence of non-equilibrating pools of apolipoproteins C-II and C-III in plasma lipoproteins

Using artificial triglyceride emulsions, we have demonstrated the presence of non-equilibrating pools of apolipoproteins C-II and C-III in human plasma lipoproteins. As the concentrations of acceptor triglycerides were increased, a greater fraction of both apoC-II and apoC-III shifted away from the native plasma lipoproteins to the artificial lipid emulsions. All of the apoC-II and apoC-III in very low density and high density lipoproteins (VLDL and HDL), however, could not be removed from native plasma lipoproteins. The percent of total plasma apoC-II and apoC-III that could be recovered in the VLDL and HDL density fractions varied when plasma from different individuals was used. When plasma samples from normotriglyceridemic subjects were used, HDL was the primary donor of apoCs. The percent of total plasma apoCs associated with HDL decreased from 60% to 25% for apoC-II and from 65% to 15% for apoC-III. When plasma samples from hypertriglyceridemic subjects were incubated with artificial lipid emulsions, VLDL was the primary donor of apoCs. HDL from hypertriglyceridemic subjects only accounted for 5-10% of total fasting plasma apoCs and did not contribute significantly to the final apoC contents of the artificial triglyceride emulsions. To evaluate the significance of the depletion of exchangeable apoCs from plasma HDL, we also examined the ability of control and apoC-depleted HDL to serve as activator for bovine milk lipoprotein lipase (LPL) in vitro. When HDL depleted of exchangeable apoCs were used as the source of plasma apolipoproteins for the activation of LPL in vitro, only 5-10% of the maximal activity obtained with native HDL was demonstrated. In fact, in the presence of comparable concentrations of HDL apoC-II, activation of LPL was the least with HDL which lacked exchangeable apoCs. Our data thus indicated that the presence of exchangeable apoC-II on HDL is necessary for the activation of LPL in vitro. This finding is consistent with our data that suggest that HDL from hypertriglyceridemic subjects do not stimulate LPL as well as HDL from normolipidemic subjects.     

Novel Perovskite-Type Oxide Catalysts for Dehydrogenation of Ethylbenzene to Styrene

We investigated novel LaMnOx perovskite-oxide (ABO₃) catalysts for effective catalytic dehydrogenation of ethylbenzene to produce styrene monomer. Comparison with industrial Fe–K catalyst, our La_0.8Ba_0.2Mn_0.6Fe_0.4O_3-δ catalyst showed higher activity. Results show that the A-site in perovskite-type oxides affected catalytic dehydrogenation activities and that the B-site affected stability of the activities.