Application of the independent molecule model to the calculation of free energy and rigid-body motions of water hexamers

The stabilities of five water hexamers (cyclic, boat, book, prism and cage structure) in the gas phase were investigated with the independent molecule model. In this model, the position and orientation of each water molecule within the hexamer are characterized with a translational vector and Eulerian angles, and then each molecule can move freely as a rigid body with respect to the others. Force field energy minimization yielded structures for each hexamer. Normal mode analyses were done on the five hexamers. Hydrogen bond strength in the hexamer decreases in the order: boat, cyclic, book, cage and prism. Hydrogen bond lifetimes also decrease in this order. By estimating the internal energy and the vibrational entropy of rigid-body motions, we determined the temperature dependence of the free energy for each hexamer in the range 100–350 K. Free energy of the hexamers increases in the previously mentioned order also. The most stable hexamer is the boat, and the least stable is the prism. The stabilities of the boat and the cyclic are very similar. The more planar hexamers (cyclic and boat) are more stable than the three-dimensional hexamers (cage and prism). Although the experiments of Liu et al. [Nature 381 (1996) 501] were interpreted in terms of a cage cluster, our calculations indicate boat is more likely.     

Accumulation of benzoic acid in suspension cultured cells of Pinus thunbergii Parl. in response to phenylacetic acid administration

The generation and accumulation of both benzoic acid (BA) and its conjugates were induced in suspension cultured cells of Pinus thunbergii by administering either phenylacetic acid (PA), a toxic metabolite of Bacillus cereus (strain HY-3) accompanying the pine wood nematode, or a lyophilized culture supernatant of this bacterium. BA conjugates reached their maximal levels in quantity two days after the administration and then decreased gradually until the 14th day, while BA increased significantly throughout this period. This pattern is similar to that in 3-year-old pine trees treated with PA, suggesting that the pathological reaction of pine tissues to the PA toxin might be involved in the pathogenesis mechanism for the pine wilt disease.     

Wind tunnel experiment for predicting a visible plume region from a wet cooling tower

We developed a new method for a wind tunnel experiment to predict a visible plume region from a wet cooling tower. The diffusion of water vapor and heat emitted from a cooling tower in a wind tunnel is estimated using a tracer gas. The instantaneous concentration of the tracer gas is measured using high-response flame ionization detectors. A moist plume-induced fog is assumed to be generated whenever the instantaneous specific humidity predicted from the concentration of the tracer gas at measured points is larger than the inferred saturation specific humidity. To confirm the validity of the present method, the results in the wind tunnel experiments are roughly compared with the observations obtained at the mechanical-draft cooling tower of the Benning Road plant. The results show that the visible plume length and height are nearly in agreement with observations and the present method has the capability to predict the visible plume region from the cooling tower.     

Pervaporation separation of water/ethanol mixtures through polysaccharide membranes. I. The effects of salts on the permselectivity of cellulose membrane in pervaporation

In the separation of water/alcohol mixtures through cellulose membranes, the addition of trace amounts of specific salts to the feed mixture (10^?5?5 × 10^?3 mol/kg) caused the marked increase of the separation factor and only the salts composed of a multivalent metal ion and a multivalent counteranion were effective for the increase of the selectivity. For example, when 1.5 × 10^?3 mol/kg CoSO₄ was added to water/ethanol mixture (35/65 wt/wt), the separation factor was 194 and the permeation rate was 5.14 kg/m² h. But, in the absence of the salt, the separation factor was only 6.7 and the permeation rate was 5.63 kg/m² h. We presumed that the increase of the selectivity by the addition of specific salts would be attributed to the contraction of the “holes” produced by the thermal motion of polymer chains and this contraction would be correlated with the conformation change of cellulose molecule.     

Novel polymerization of divinyl monomer to polyester catalyzed with organocobaloxime

The polymerization of ethylene bis(-ethylacrylate) to polyester was catalyzed with benzyl(bisdimethylglyoximato)(pyridine)cobalt(III). Although the -ethylacrylic ester does not radically homopolymerize, radical addition to the carbon-carbon double bond yields the corresponding radical. This radical readily reacts with the cobalt(II) complex involved to form a carbon-cobalt bond. Dissociation of the generated bond accompanying fast -hydrogen elimination results in a new carbon-carbon double bond and the cobalt hydride which rapidly adds to the ethylacrylate moiety to form a carbon radical which may react with the cobalt(II) complex. Through the sequence of these reactions, the novel polyester linkage was expected to be formed. Actually, the cobaloxime catalyzed reaction competed with radical propagation, and the polymer consisted of the polyester linkage (32%) and the consecutive ethylacrylate units with two types of unsaturated pendant groups (68%).     

Application of the independent molecule model to elucidate the dynamics of structure I methane hydrate

Raman spectroscopy has exhibited the C–H stretch (A₁ mode) frequency ν₁ of hydrated methanes at 2915 cm⁻¹ for the 5¹² cage and 2905 cm⁻¹ for the 5¹²6² cage. These values are lower than the frequency of 2916.5 cm⁻¹ in gaseous methane. In this paper, we theoretically examine the Raman spectra observed in methane hydrate by normal mode analysis using the independent molecule model. By a breakdown of the symmetry, the four frequencies in modes A₁, E, T₂ and T₂ observed in gaseous methane are separated into nine frequencies in the hydrate. It is necessary to consider the anharmonic potential energy within methane and hydrogen bonding between methane hydrogen and water oxygen in order to get a result in qualitative agreement with experiment. The frequency in the 5¹²6² cage is shifted downward in comparison to the one in 5¹², and the frequencies in the both cages are also shifted downward compared with the frequencies in gas. Calculations are also reported for the isotopic methane (CD₄, ¹³CH₄) hydrates.     

A 513‐ppi FFS‐mode LCD using technique for changing part of active layer of oxide semiconductor to transparent electrode

We have established a technique for changing part of an active layer of an oxide semiconductor (OS) to a transparent electrode in order to achieve an aperture ratio of 50% or higher and a bezel width of 1 mm in an fringe field switching (FFS) mode LCD panel with a high resolution of 513 ppi. Furthermore, we have prototyped an LCD panel by examining a driving mode that enables low‐frequency driving.     

Solid Solubility of Aluminum in O'-SiAlON

Energy -dispersive X-ray spectroscopy(EDXS) analysis was used to investigate the solid solubility of aluminum ( X value) in O -SiAlONs (Si_2-xAl_xO_1+xN_2-x)using transmission electron microscopy in the scanning transmission electron microscopy mode. Lattice parameter a of the O -SiAlONs increased with increased X value =0.16. The X value of 0.16 was the maximum of the X value in SiAlONs precipitated from a Si-Al O-N melt which was sasturated with aluminum and nitrogen at 1700^oC.The X value of O -SiAlONs measured by EDXS were smaller than those calculated on the assumption that the Si₂N₂O structure accommodated the total amount of the doped Al₂O₃ . This result suggested that a considerable amount of Al₂O₃ remained in grain boundaries as secondary phases.