Resonance energy exchange effects in atmospheric transmission due to pollutants

It is shown that resonant energy exchange between two gases can alter the absorption of radiation by either, and that hydrocarbons present up to 100 ppm in the atmosphere as pollutants affect its absorption at 10.6 μ. This reduces the initial cooling time reported in the transmission of 10.6 μ laser beams in the atmosphere.     

Electrical conductivity and dielectric loss in doped Pb(NO3)2 single crystals

dc ionic conductivity measurements were made on single crystals of Pb(NO₃)₂ doped with monovalent Na⁺ and K⁺ in the temperature range of 100–400°C. In the extrinsic region the conductivity was found to decrease with Na⁺ having a smaller ionic size, and to increase with K⁺ with larger ionic size compared to the host Pb ion. Conductivity is attributed to the mobility of anti-Frenkel defects as in the case of PbF₂. Dielectric loss measurements were made on the Pb(NO₃)₂: K⁺ system in the frequency range of 300 Hz to 20 kHz at different temperatures. Impurity vacancy pairs of the type K⁺-(NO^-₃)_V are found to be responsible for the observed dielectric loss peaks. The maximum peak frequency is found to increase with temperature.     

Average potential energy criterion: Force fields of some planar XY3 and tetrahedral XY4 molecules

Minimization of the average potential energy contributions from bending deformations due to zero point vibration serves as a good criterion for fixing the harmonic force fields in planar XY₃ and tetrahedral XY₄ nonhydride molecules. An explanation based on the concept of rehybridization of the orbitals of the central atom during a bending vibration is offered.     

Search for physiologically active compounds

A few halo, nitro and methoxy substituted 1:2-naphthoquinones with the substituents in both the benzenoid and the quinonoid rings have been synthesised and evaluated for their fungistatic properties. Among the quinonoid compounds tested 3:4-dichloro-1:2-naphthoquinones exhibited the highest activity.     

The dirac-schwinger covariance condition in classical field theory

A straightforward derivation of the Dirac-Schwinger covariance condition is given within the framework of classical field theory. The crucial role of the energy continuity equation in the derivation is pointed out. The origin of higher order derivatives of delta function is traced to the presence of higher order derivatives of canonical coordinates and momenta in the energy density functional.     

Direct and inverse error estimates for finite elements with mesh refinements

The finite element method is used to solve a second order elliptic boundary value problem on a polygonal domain. Mesh refinements and weighted Besov spaces are used to obtain optimal error estimates and inverse theorems.Research performed while at the University of Maryland under a Fulbright fellowshipResearch supported in part by the Department of Energy under the contract E(40-1)3443Research supported in part by the National Institutes of Health under the grant 5R01-AM-20373     

Some applications of the discrete fourier transform to problems of crystal lattice deformation II

The method elaborated in [1] is applied to the solution of some problems for a plane lattice and the linear chain. The method can be used to investigate deformations around crystal lattice defects.

---

, [1] . .