Flow injection determinations of polyphosphates based on colored metal complexes of xylenol orange and methylthymol blue

Substitution reactions between samples and colored metal complexes, such as magnesium-methylthymol blue and cerium(III)-xylenol orange, are applied to flow injection determinations of orthophosphate, diphosphate, triphosphate and EDTA. Various types of manifold with a stopped-flow device are used; the importance of addition of reagents in a logical sequence is stressed. Kinetic and thermodynamic factors associated with the substitution reactions were found to be significantly reflected in the f.i.a. profiles and stopped-flow signals. The working ranges of the methods are 10^-5–10^-4 M.     

Flow injection analysis of inorganic polyphosphates

Flow injection analysis is applied to the determination of orthophosphate and polyphosphates, such as diphosphate and triphosphate. A strongly acidic solution containing molybdenum(V) and molybdenum(VI) is used as the carrier so that hydrolysis of polyphosphates and color development of the resultant orthophosphate can be achieved simultaneously. For complete chemical reaction, the temperature of the reaction coil is maintained at 140° C. Application of a back-pressure coil is then necessary to eliminate the noise caused by gas bubbles. Total amounts of inorganic polyphosphates can be determined at a sampling rate of 45 samples per hour with a relative standard deviation of less than 1%. In addition, the flow injection system is shown to be useful as a post-column detector for high-performance liquid chromatography of inorganic polyphosphates. The efficiency of this system is compared with that of an air-segmented flow system.     

Negative ion mass spectra of salicylaldehydato and 2-hydroxy-1-naphthylaldehydato complexes of Co(II), Ni(II) and Cu(II): Consecutive and competitive eliminations of CO and H2CO

The negative ion mass spectra of some divalent metal complexes, ML₂, have been measured, where M?Co, Ni and Cu, and LH = salicylaldehyde or 2-hydroxy-1-naphthylaldehyde. All compounds yield intense molecular anions. The mass spectra of these compounds suggest that consecutive and competitive eliminations of CO and H₂CO, and various types of hydrogen migrations are involved in the fragmentation of the molecular anions. The mechanism of the fragmentation process and metastable peaks observed are also discussed.     

Application of the opal-glass method for ion-exchanger spectrophotometry

A simple and precise method for the measurement of the net absorbance of colored species sorbed on ion-exchange resins is reported. Identical opal-glass plates are inserted on the transmission sides of both the sample-cell and blank-cell compartments of the spectrophotometer. Absorbances of sample-resin layers are measured against a blank-resin layer as reference. Scattering effects caused by resin particles are almost eliminated by using opal glass. For the determination of chromium(VI) with diphenylcarbazide reproducible calibration lines were obtained without tedious compensation methods.     

Nonlinearity in cooperative systems-dynamical Bethe-Ising model

The dynamics of the short-range order as well as the long-range order in the nonlinear cooperative system is investigated specifically for a kinetic Ising model in the Bethe approximation. The phenomena of critical slowing down near the transition temperatureT _c and anomalous fluctuation belowT _c are directly related to the instability of the long-range order. The dynamics of the short-range order is essentially a fast mode and is noncritical. However, through the nonlinear coupling the short-range order is also influenced by the critical behavior of the long-range order.     

Generalization of analytic energy derivatives for configuration interaction wave functions

This paper takes the form of a review including some original contributions. A fresh derivation of analytic energy derivative expressions for configuration interaction (CI) wave functions is presented. In this method the CI energy is described by _IJC_IC_J(H _IJ-_IJE) so that the orthonormality condition is explicitly included therein. In the sequence of differentiations up to fourth order it will be demonstrated that each derivative may be expressed in terms of (H _IJ-_IJE) and its derivatives in a symmetric way with respect to the interchange of differential variables. In a similar manner, the CI variational condition may be described in an equation which explicitly includes the normalization condition. It is shown that the differentiation of the modified variational condition produces the coupled perturbed configuration interaction (CPCI) equations in directly soluble and compact forms. The necessary formulae for the energy derivatives up to fourth order and the CPCI equations up to second order are explicitly given.     

Studies on tribology

In high speed rotating machines such as turbines and generators, vibrations of a rotating shaft often hinder the smooth operation of the machine or even cause failure. Oil whip is one of such vibrations due to oil film action of journal bearing. Its mechanism and preventive method is explained and proposed in this paper. Further theoretical and experimental analyses are made for considering heat generation and temperature rise in hydrodynamic lubrication. The usefulness of the lubrication theory based on the k-epsilon model is also shown for bearings with high eccentricity ratios. In the latter half of this paper, water lubrication, nitrogen gas lubrication and tribo-coated indium lubrication are shown as new promising methods, and their mechanisms are discussed and the importance of tribo-layer is explained. Some mechanisms of wear are introduced for better understanding of tribo-layer. In the last part of this paper, the mechanisms of generating static friction are shown for the cases of plastic contact and elastic contact, which is the base for understanding the mechanism of initiation of macroscopic sliding.