When a plated steel sheet is welded, it is repaired by coating or spraying as the plating layer is damaged. In order to ensure corrosion resistance after painting, pre-treatment before painting is important. Therefore, in this study, we investigated the influence of each pre-treatment for painting repair on corrosion resistance after painting. Our research also focused on the surface modification effect by fine particle peening treatment for each pre-treatment. Then, we considered the difference in corrosion resistance of each sample from a histological viewpoint by X-ray diffraction and an electrochemical viewpoint by cathode polarization. Our results indicated that Ni could be attached to the surface of the material to be treated by fine particle peening treatment, using Ni powder. They also indicated that the samples coated after the fine particle peening treatment, using the Ni powder, had a smaller red rust generation area and had superior corrosion resistance than the other samples. The results suggested that this factor is attributed to the formation of corrosion products with high inhibitory effect on oxygen reduction reaction on the surface of the material to be treated, because Ni had become attached to the surface of the same.
Effects of addition of poly(phenazasiline) (PPhenaz) to plastic blends were investigated. PPhenaz was blended with poly(lacticacid) (PLA), poly(ε-caprolactone) (PCL), and lysine triisocyanate (LTI), then the blend composites were molded. The PPhenaz containing blend composites showed strong fluorescence. Fluorescence λmax of the PPhenaz containing blend composites were not changed by addition of LTI. This fluorescence behavior was different from that resulting from addition of dibenzazepine-containing polymer. Addition of PPhenaz to PLA/PCL/LTI blend composite improved impacts trength. These results suggested that PPhenaz was usuful as a functional additive for plastic blends.
Development of fluorescent sensing methods for detection and quantification of a trace amount of water in solutions, solids, the atmosphere and products has received considerable attention in recent years from the viewpoint of fundamental studies in photochemistry, analytical chemistry and photophysics, and is eagerly anticipated in industry because of their potential applications to environmental and quality control monitoring systems. Karl Fischer titration method is a classic titration method in analytical chemistry that uses coulometric or volumetric titration to determine trace amounts of water in samples such as solid and solution. Actually, Karl Fischer titration method has sufficient accuracy, but is difficult to visualize water in sample and on the surface of sample. On the other hand, if we can develop fluorescence analysis for detection and quantification of water, this technique allows not only sufficient accuracy but also visualization of water. This paper provides the fluorescence analysis for detection, quantification and visualization of water based on PET (photo-induced electron transfer) of fluorescent dyes and their fluorescent sensing mechanism for detection and quantification of a trace amount of water in solutions.
Organic dyes showing strong emission even in aggregates and the control of emission properties based on interchromophoric interactions have recently been attracting attention. Emission properties, i.e., emission quantum yields and lifetime, can be quantitatively investigated based on the decay rate constants from the excited states. The author's group have recently reported the design concept of a cyclic dimer compound showing high fluorescence quantum yield and long emission lifetime, based on interchromophoric interactions and the control of molecular orbitals. In this article, we will describe the molecular design strategy toward highly emissive organic dyes based on decay rate constants and the control of frontier molecular orbitals.
The basic function and formulation of paints are described. The basic function of paints is to decorate and protect objects through the creation of a dry paint film by a “flow-solidification” process. As the formulation of a paint depends on the required functions of the dry paint film, a large variety of paint types exist.