Structural and chemical effects on the SiKβ X-ray emission spectra for silicates and silico-phosphates

The SiKΒ X-ray emission spectra for several silicates and silico-phosphates were measured using a high-resolution X-ray fluorescence spectrometer with two InSb(III) analyser crystals. Molecular orbital calculation analysis for the obtained spectra was performed by a SCC-DV-Xα method and the energy positions and relative intensities of the spectral fine structures were calculated with Slater's transition-state method. The calculated results interpreted the spectral profiles successfully. The energy shifts of the SiKΒ main peak were also discussed in terms of the electronegativity of the second-nearest-neighbour atoms. These shifts were attributed to the changes in the stability of the Si-O bonds due to the existence of second-nearest-neighbour P atoms.     

Oxygen doped Ge crystals Czochralski-grown from the B2O3-fully-covered melt

Local vibrations of oxygen in Ge crystals grown from a melt fully covered by B₂O₃ were evaluated by Fourier-transform infrared spectroscopy. Ge single crystals containing oxygen were grown by the Czochralski method under various growth conditions. Oxygen concentrations in the crystals were determined to be in the range between 8.5 × 10¹⁵ and 5.5 × 10¹⁷ cm⁻³ from the infrared absorption at 855 cm⁻¹ originating in local vibration of Ge-O_i-Ge quasi-molecules. Absorption peaks relating to GeO_x, SiO_x and Si-O_i-Si were not detected in the as-grown crystals. The calibration coefficient for determining oxygen concentration in Ge crystals from the absorption peak intensity at 1264 cm⁻¹ was estimated to be 1.15 × 10¹⁹ cm⁻².     

EELFS as a new tool of local structural characterization of solid surfaces

A new apparatus to obtain information on local structures and chemical states of solid surfaces has been constructed, with which we measure electron energy-loss fine structures (EELFS), excited by electrons of a few keV incident at a grazing angle. We describe results about O/Ni(100) and O/W(100) systems, where we extensively take advantage of anisotropy in regard to momentum transfer of the probe electron and high surface sensitivity of this technique.     

EXPERIMENTAL AND NUMERICAL STUDY ON GAS FLOW IN THE GRID ZONE OF JETTING-FLUIDIZED BEDS

A grid model describing the gas flow and interchange in the grid zone of jetting fluidized beds is proposed. Based on this model, longitudinal gas concentration profiles in the jet and annulus are calculated. The longitudinal gas concentration distribution is also experimentally investigated in a jetting fluidized bed with an inside diameter of 50 mm at the ambient temperature, and a jetting fluidized bed with an inside diameter of 80 mm at high temperatures. Comparison between the calculated and experimental results has shown that the experimental profiles can be qualitatively predicted by the grid model. The results indicated that the concentration in the grid zone depends on the gas exchange between the jet and the annulus, and the net gas flow from the jet to the annulus. The gas exchange rate is mainly affected by the inlet gas velocity from the nozzle. The present study is thought to be helpful to understand the grid gas behavior in the jetting fluidized bed coal gasifier.     

The leveling of thermosetting waterborne coatings. Part II: Drying of coated wet films

Evaporation behavior of water/solvent blends was estimated using the universal functional activity coefficient, UNIFAC, method. The evaporation rate from a free surface of a waterborne coating, WBC, containing a co-solvent was experimentally determined. These results were used to estimate the evaporation rate from wet films of a WBC containing a variety of co-solvents with a range of initial thickness. Knowing the composition of the WBC during the drying process, the change in the viscosity and the surface tension was determined. The results strongly support the development of a surface tension gradient in the film. It is also suggested that a surface tension gradient would accelerate the leveling of the ribs if a proper co-solvent were employed.     

Analysis of interaction between liposome membranes induced by stress condition: Utilization of liposomes immobilized on indium tin oxide electrode

NBD-cholesterol (NBD-Ch)-modified liposome was immobilized on indium tin oxide (ITO) electrode via the covalent binding method. The transfer of NBD-Ch between the immobilized liposomes and the target liposomes was observed by using a fluorescent microscope. The addition of liposome suspension co-incubated with α-chymotrypsin or stimuli-responsive polymer to the surface of the above ITO electrode, enhanced the liposome–liposome interaction, resulting in the promotion of NBD-Ch transfer. The apparent transfer rate constant of NBD-Ch was found to be correlated with the index for the liposome–liposome interaction evaluated by an immobilized liposome chromatography. This suggests that the present method using the liposome-immobilized ITO electrode was effective to evaluate the liposome–liposome interaction induced by the protein or the stimuli-responsive polymer under stress conditions.     

A fundamental study on recovery of copper with a cation exchange membrane: Part 2 — Transfer rate of copper and hydrogen ion through a cation exchange membrane

Transfer rates of copper and hydrogen ion through a cation exchange membrane were measured experimentally for the systems of Cu/H-SO₄ and Cu/H-NO₃. Transfer rates of anions in the membrane were also measured, and they were negligible compared to those of the cations. Cupric ion and hydrogen ion transfer in a ratio of 1:2 and in opposite directions. The self-diffusion coefficient of cupric ion in the membrane is obtained from the transfer rate of copper in high concentrations of sulfuric or nitric acid solutions using the equilibria data obtained in our previous work. The coefficient of the hydrogen ion is similarly obtained.     

Full scale investigation of GCL damage mechanisms in small earth dam retrofit applications under earthquake loading

This paper reports results of full scale testing to further explore potential GCL damage mechanisms in earth dam retrofit applications in seismically active areas; in particular, to a) investigate whether shear displacements could reduce the magnitude of GCL panel overlap during earthquake shaking; b) explore the influence of gravel particles on GCL thickness at localised point of contact; and c) observe the consequences of an accidental exposure of an uncovered GCL to short duration rainfall in terms of moisture content and effects during subsequent compaction. The results of these experiments indicate that even under severe shaking no movements were detected at the GCL panel overlap. Whereas gravel particles were observed to locally reduce the thickness of the GCL to 2.2 mm, no plowing of the particle into the GCL occurred due to a lack of shear displacement at the interface, resulting in no localised internal erosion through the barrier. Furthermore, hydration of GCL panels during construction due to surface wetting was observed to result in a state of hydration less than its post-construction state. These results indicate that although each of the three GCL damage mechanisms cannot be ruled out to ever be relevant in practice, the performance of the GCL retrofitted earth dam tested was satisfactory under even severe Level 2 earthquake shaking, and suggests that the retrofitting of small earth dams with GCLs is a promising strategy to improve their static and seismic resistance.