Development of spectroscopic transmission-type four detector polarimeter

We have developed a spectroscopic transmission-type four detector polarimeter (T-FDP). It consists of a detector head and a multichannel spectrometer equipped with a two-dimensional CCD detector. Inside the T-FDP, three cubic beam splitters are aligned in a straight line and they are rotated relative to each other. From the responses of the spectroscopic T-FDP to five inputs with known polarization states it is possible to determine the characteristic matrices of the T-FDP at various wavelengths. The trajectories of the experimentally measured polarization states on the Poincaré sphere agree well with theoretical predictions. These results demonstrate the feasibility of using the T-FDP for spectroscopic ellipsometry.     

Three-dimensional organization of collagen fibrils during corneal stromal wound healing after excimer laser keratectomy

PURPOSE: To investigate the structural changes in corneal stromal collagen fibrils after excimer laser keratectomy in relation to the degree of corneal haze. SETTING: University of Tokyo Hospital, Tokyo, Japan. METHODS: Corneal haze was quantitatively measured by analyzing the light scattering in Scheimpflug images of the corneas of white rabbits after excimer laser keratectomy. Collagen fibril structure was examined using scanning electron microscopy after chemical digestion with sodium hydroxide solution; the same specimens were examined by transmission electron microscopy after re-embedding. RESULTS: Corneal haze reached a peak 4 weeks after excimer laser keratectomy and then gradually decreased. The collagen fibrils of the normal cornea were regularly arranged parallel to the surface of the cornea, with small interfibrillar distances. After excimer laser keratectomy, the arrangement was highly disordered, with increased interfibrillar distances. These structural changes were most prominent 4 weeks after excimer laser keratectomy. CONCLUSION: The structural changes in the collagen fibrils of the corneal stroma, especially the increase in interfibrillar distances and the disordered arrangement, were associated with corneal haze after excimer laser keratectomy.     

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.     

The viscoelastic properties of soybean curd (tofu) as affected by soymilk concentration and type of coagulant

The viscoelastic properties of different types of tofu were investigated. Soymilk concentrations were 5, 6, 7, 8 and 9%. Coagulants used were 30 mm CaSO₄ or 30 mm glucono‐delta‐lactone (GDL). As the concentration of soymilk was increased viscosity and handling difficulties increased. A high concentration of soymilk in tofu gave a high break stress and produced hard tofu. The four‐element Burgers model fitted the creep behaviour and both viscous and elastic parameters could be acquired from model analysis, reflecting changes in elasticity and viscosity of tofu. The constant viscous parameter in the model increased with increasing soymilk concentration. The viscous parameters of viscoelastic materials like tofu gel, obtained from small deformation tests, seemed to correlate, to some extent, with the break stress obtained from large deformation tests. For hard tofu production increasing the soymilk concentration within a certain range and the partial replacement of calcium sulphate coagulant by GDL could be effective options.     

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.