An edge-coloration theorem for bipartite graphs with applications

An edge-coloration theorem for bipartite graphs, announced in [4], is proved from which some well-known theorems due to König [5] and the author [2, 3] are deduced. The theorem is further applied to prove the “dual” of a theorem due to Lovász [6].     

Enhancement of self focusing of laser beams in a degenerate magnetoactive solid state plasma

This paper presents an investigation of the enhancement of self focusing of high frequency EM waves in a compensated degenerate magnetoactive solid state plasma. The nonlinearity in the dielectric constant responsible for self focusing arises due to nonuniform heating and consequent redistribution Of carriers. A rigorous kinetic treatment valid beyond the perturbation limit has been presented assuming the carrier relaxation time to be energy dependent. The results show that the self-focusing of extraordinary waves is enhanced while that of ordinary waves is reduced with $\text{ω}{}_{\mathrm{c}}\text{ω}$ increasing. However the focusing of extraordinary waves is not possible when ω_c > ω. The effect of degeneracy is also found to enhance the self-focusing of the waves while that of the enhanced absorption is to suppress the self-focusing process.     

Non-specific binding in the affinity chromatography of chymotrypsin

The strong and specific binding of chymotrypsin on chromatographic columns containing agarose substituted with N--amino Caproyl- -tryptophan methyl ester is abolished when the -amino groups on the surface of the enzyme are reacted with acetic anhydride. Because the catalytic properties of the acetylated chymotrypsin are identical to those of the underivatized enzyme, it is concluded that the high affinity of chymotrypsin for this column is not due solely to biospecific inhibitor binding, which is by itself very weak, but requires reinforcement through weak non-specific interactions with the column support. It is postulated that these non-specific interactions include electrostatic interactions between agarose matrix and positively charged lysyl residues on the enzyme. The results demonstrate for the first time that residues on the surface of an enzyme not associated with its active site can play an important role in some chromatographic systems previously thought to be based on purely biospecific interactions.     

Hole-phonon scattering in zinc doped GaSb

The phonon thermal conductivity values in Zn-doped GaSb are explained for hole concentrations ranging from 2 × 10¹⁷ to 4 × 10¹⁹ cm^-3. The concentration dependence of thermal conductivity above 3 × 10¹⁸ cm^-3 is similar to other doped materials and is explained by considering the scattering of phonons by free electrons (holes) given by Ziman and Kosarev and applying the screening effects suggested by Crossby and Grenier. The density-of-states effective mass is kept constant and the dilatation deformation potential is found to increase with hole concentration. For impurity concentrations less than 3 × 10¹⁸ cm^-3, the thermal conductivity is found to increase with hole concentration. Since this concentration region is below the metal-insulator transition, the theory of scattering of phonons by holes bound to the impurity atoms explains the conductivity results. The values of acceptor hole radius and deformation potential constants are in agreement with the experimental values.     

Transient behaviour of a double-channel Markovian queue with limited waiting space

For a double channel Markovian queue with finite waiting space the difference equations satisfied by the Laplace transforms of the state probabilities at finite time are solved and the state probabilities are obtained in a simple closed form which can be easily used to find the important parameters of the system.     

Electron diffraction data as a constraint in the determination of force field of thallous halide dimers

Electron diffraction data have been used as a constraint in the determination of force field for Tl₂F₂ having planar rhombic structure. The L-F approximation method, recently given by us, has also been applied to evaluate force constants for thallous halide dimers,e.g. T1₂F₂ and T1₂Cl₂. The results have been compared with the available experimental data in order to check the validity of the present work. It is concluded that non-bond experimental mean amplitudeU ₁..._Tl for Tl₂F₂ is capable of fixing the force field and L-F approximation gives reasonably good force fields for the two thallous halide dimers now under study.     

NGR study of pyrrhotites obtained in coal hydroliquefaction

Iron Mössbauer spectroscopy has been performed on 38 residues of hydroliquefaction of the French bituminous Freyming coal, without and with added iron based catalysts. 56 to 94 % of the area of each spectrum was occupied by 2, 3, 4 or 5 sextets of Fe_1?xS, either at 295 K or at 78 K or at 4 K. Values of H at 295 K are proposed: 299, 283, 268, 254, 242 and 228 kOe, ±3 kOe, associated with δ(α-Fe)=0.72±0.02 mm/s. The vacancies responsible for the values of H are likely to be randomly distributed. The best accuracy on the relative intensities cannot ensure a precise determination of the overall stoichiometry, so that a better knowledge of the samples is given by the distribution of the Fe sites.     

Pyrido[2,3-d]pyrimidines and pyrido[2,3-d; 5-d′]dipyrimidines as potential chemotherapeutic agents. VIII

Reactions of 5-dimethylaminomethylene-6-imino-1,3-dimethyluracil hydrochloride (1) with active methylene compounds 2 and 4 yielded bi- and tricyclic heterocyclic compounds 3 and 5 . All the prepared compounds were screened for chemotherapeutical activities but none were active.