Transmission Bandwidth Expansion of SI-POF Using WDM-Pulse-Position Modulations

WDM-Pulse-position modulation technique in SI-POF transmission is proposed to overcome the limitation from mode dispersion. It can expand the flat transmission bandwidth to 80MHz with 100m-fiber length.     

Studies on the syntheses of heterocyclic compounds—CCCLXXI Synthetic approach to camptothecin

Picolinic acid 1-oxide (III) was esterified with thionyl chloride and ethanol to the ester IV, whose treatment with phosphoryl chloride gave ethyl 6-chloropicolinate (V). Hydrolysis of V with hydrochloric acid gave 6-oxo-1,6-dihydropicolinic acid (VI). Simultaneous condensation and cyclisation of the methyl ester of VI with methyl acrylate in the presence of sodium carbonate in dimethylformamide yielded the bicyclic ketoester (VIII). Hydrolysis and decarboxylation of VIII with hydrochloric acid gave 3-keto-pyrrolidino[2.1-f]-2-pyridone (IX). Friedänder condensation of IX with 2-aminobenzaldehyde gave the camptothecin analogue II.     

Two-loop double-pole counter lagrangian

On the basis of the background field method, extended one-loop counterterm formulae are derived, and a method to get the two-loop double-pole counter lagrangian is given. As an example, the double-pole divergences of ξ²X³ counterterms are obtained.     

Kinetics of bimolecular chemical reaction by a modified diffusion equation

In order to describe the kinematical behavior of the bimolecular chmical reaction in a dilute solution of species characterized by a single diffusion coefficient and by some nonuniform spatial distribution of the active site, a diffusion equation with a simple sink term is derived by reducing the many-body problem to a one-body problem. The equation is normalized with the concentration of unreacted particles. The so-called second-order reaction rate constant can be calculated from the solution of the equation. The equation is applied to the intermolecular termination reaction of polymer radicals on the assumption of free draining. The reaction rate constant gradually decreases with time.     

Enantioselective synthesis of (6S,7S,9R,10R)-6,9-epoxynonadec-18-ene-7,10-diol,a marine natural product

The title compound has been synthesized in enantiomerically pure form using diethyl L-tartrate as a chiral template.     

Phase equilibria of the Mn---Fe---O system (Fe/Mn = 2)

Phase equilibria of the Mn---Fe---O system (Fe/Mn = 2) were studied in the temperature range 1223–1393 K and in oxygen partial pressure from 10⁻¹ to 10⁵ Pa by measuring the electrical conductivity and the weight of the sample. The standard enthalpy and entropy changes per one mole oxygen for the phase boundary reaction between spinel and spinel + hematite were calculated from thermogravimetric data. A slight break in the plots between the oxygen partial pressure and weight change at constant temperature was observed in the single phase of manganese ferrite, where the lattice constant also showed a break in the plots of lattice constant against oxygen partial pressure. The oxygen potentials were calculated by assuming that the break point in the plots between the oxygen partial pressure and weight change is the stoichiometric composition of manganese ferrite.     

A galvanic gas sensor using poly (ethylene oxide) complex of silver trifluoromethane sulphonate electrolyte

Summary A galvanic sensor for monitoring nitrogen dioxide was developed by using a poly(ethylene oxide) complex of silver trifluoromethanesulphonate electrolyte. The sensor, which is expressed as Au/P(EO)_4.5 AgCF₃SO₃/Ag, is a small disk (i.d. 13 mm). The polymeric electrolyte film was made by casting the mixture of acetonitrile solutions of both P(EO) (MW 6×10⁵) and AgCF₃SO₃. The working electrode was made by sputtering of gold in argon. The thicknesses of the desposited gold, polymeric electrolyte film and silver are 25 nm, 30 m and 1 mm, respectively. When the sample gas containing nitrogen dioxide impinges at 20 ml min^–1 on the gold cathode, the current flowing in the external circuit was linearly related to the concentration of nitrogen dioxide from 20 ppb to about 10 ppm. The current efficiency of the cell was 0.051%. The cell's response time was about 2 min for 0.5 ppm of nitrogen dioxide.