Demethylation reactions of 4-amino-N-(2,6-dimethoxy-4-pyrimidinyl)benzenesulfonamide (sulfadimethoxine) in strongly basic aqueous solution

Hydrolysis of 1 in strongly basic aqueous solution afforded mono- and didemethylated products 2,3 and 4 , that are postulated as the metabolites of 1 in some animals. This hydrolytic demethylation was shown to proceed stepwise via mono-demethylation to give 2 and 3 , followed by their further demethylation to 4 . The hydrolytic reactivity of 1–3 was rationalized based on MO calculation results and ¹³C nmr data.     

High-field susceptibility and magnetization in Fe-Ni invar alloys

The high-field susceptibility of Fe-Ni Invar alloys does not give rise to a sudden increase at the Curie temperature. The decrease in magnetization with increasing temperature is attributed to the T² term as well as to the spin wave term for Fe-Ni Invar alloys.     

Fuzzy importance in fault tree analysis

In fault tree analysis, system success or failure can be described by the state of the top event, which is usually defined by a so-called structure function. In this paper, we attempt to simplify the calculation process of the structure function and to newly define the state of the top event by the membership function, using fuzzy sets theory. Furthermore, it is shown that the importance of each basic event can be evaluated through fuzzy operations. The method proposed herein is demonstrated by some examples with respect to the failure analysis of structures.     

Detection properties of an optical fiber probe for laser speckle velocimetry

Temporal power spectra of the speckle signal detected by a simple optical fiber probe are analyzed as a function of the laser spot size at a moving scatter plate, the velocity of the plate, the core diameter of the detecting fiber and the numerical aperture of it. The fiber probe is shown to be useful for velocity measurements of the moving scatter plate.     

Evaluation of dispersion in a flow injection system by electrochemical detector and personal computer

Summary The evaluation of dispersion in a FIA system, which is one of the indices of analytical sensitivity and separation, has been studied with an electrochemical detector and personal computer. Two different modes are applied to evaluate the degree of dispersion. One is a flat portion type mode, the other a hanging bell type mode. From these experiments it is possible to easily estimate the degree of dispersion in a FIA system concerning low dispersion (1 < D < 3) and medium dispersion (3 < D < 10), as discussed by Ruzicka and Hansen. Two regulation methods for sample volume in a FIA system are also discussed.

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Untersuchung der Dispersion in einem Fließinjektionssystem mit Hilfe von elektrochemischem Detektor und Personal Computer

Zusammenfassung Die Dispersion in einem Fließinjektionssystem, die für die analytische Empfindlichkeit und Trennung von Bedeutung ist, wurde nach zwei verschiedenen Methoden ausgewertet. Es ergab sich, daß der Dispersionsgrad im niederen (1 < D < 3) und mittleren Bereich (3 < D < 10) (entsprechend den Untersuchungen von Ruzicka und Hansen) leicht berechnet werden kann. Zwei verschiedene Regulierungsmethoden für das Probevolumen in einem FIA-System werden ebenfalls diskutiert.

     

New Laser Speckle Flowgraphy System Using CCD Camera

A new technique is developed to visualize the blood flow map of the human retina using laser speckle phenomena. Despite use of an ordinary CCD camera as the detector, the performance of laser speckle flowgraphy system for the analysis of ocular blood circulation is greatly improved to achieve higher resolution and a wider field of view for blood flow mapping. It is shown that the quality of the blood flow map is influenced by the sampling format of the pixel points in the space- and time-varying speckle field.