Feed gap aperture field and input admittance of an infinitely longinsulated antenna

Expressions are derived for the input admittance and aperture electromagnetic fields in the feed gap of a solid insulated antenna of infinite extent. This is done by solving the boundary value problem where the fields are represented by Fourier series built up by superposition of basic sets of φ-independent cylindrical waves. Such waves are obtained from the solution of the Helmholtz equation governing the z-directed electric Hertzian potential. The axial aperture electric field in the gap is in the form of a Fourier-Bessel series and is used to find the input admittance. Results are plotted for the aperture fields and tabulated for the input admittances at different radii, insulating shell dielectric constants, and gap widths     

Phonons in mixed superionic fluorites (BaF<Subscript>2</Subscript>)<Subscript>1-x</Subscript>(LaF<Subscript>3</Subscript>)<Subscript>x</Subscript>

In recent years, the fluorite-structured solid solutions with the general formula, (MF₂)_1-x(RF₃)_x (M = Ca, Sr, Ba, Pb and R is a rare-earth element or Y), have been the subject of numerous experimental studies focussed on their superionic properties. The overall cubic crystal symmetry (space group Fm3m) is conserved up to x ≶ x_max, where x_max ⊁ 0.4-0.5 depending on M and R. The zone centre phonons and phonon dispersion along three symmetry directions of the mixed superionic compound (BaF₂)_1-x(LaF₃)_x have been investigated by applying de Launey angular force model for x ≶ x_max. The calculated results are compared and explained with available experimental results.     

Studies on the distribution of cholinesterases: activity in the human and dog heart

The distribution and postnatal variation of cholinesterase (ChE) activity were studied in 25 human and 25 dog hearts. The observed distribution pattern is remarkably constant, In dog hearts, the pattern is as follows: sinus node (SN) greater than left atrium (LA) greater than right atrium (RA) greater than right ventricle (RV) congruent to left ventricle (LV). The average acetylcholinesterase (AcChE) activities as expressed in international units per g wet tissue are: 1.66 (SN), 1.14 (LA), 0.70 (RA), 0.22 (RV), and 0.21 (LV). In human hearts, the AcChE distribution follows the pattern of RA greater than LA greater than RV congruent to LV with corresponding average activities of 1.70, 1.38, 0.51, and 0.44 IU. The postnatal variation of ChE activity is most pronounced in the RS of the heart in both species. The average AcChE activity in the RA of the newborn puppies is 0.51 IU as compared with 2.27 IU in newborn infants. In the adult heart, however, the average atrial AcChE activity is nearly identical (1.02 IU) in both species. An additional difference is the large (34-64%) contribution of butyrylcholinesterase (BuChE) to the total activity in dog hearts whereas the contribution of BuChE is small (7-15%) in human hearts.     

Computer-aided design of suboptimal feedback controllers using optimal low-order models

The fully automated design of optimal or near-optimal feedback controllers is considered for least-pth and minimax cost functions. Solutions are obtained by approximating to the desired optimal output by a rational function. Optimal results for a 2nd-order model and suboptimal responses for the corresponding 7th-order linear system are used to illustrate the method.     

Heavy sarcocystosis in the ocular musculature of cattle and buffaloes

A high prevalence of 71.5 per cent and 69.7 per cent of sarcocystosis was observed in the ocular musculature of cattle and buffaloes respectively, in Bihar, India. The concentration of cysts in the eye muscle was also usually heavy. Ocular musculature appears to be a preferred site for the development of Sarcocystis in these intermediate hosts, second only to the heart muscle. The species of Sarcocystis involved in the present study were morphologically indistinguishable from S. cruzi in cattle and S. levinei in buffaloes. This appears to be the first report on the occurrence of S. cruzi and S. levinei in ocular musculature.     

Comments on "Thermal transient effects in optically pumped repetitively pulsed lasers"

The expression for temperature transients for optically pumped cylindrical laser rods has been derived. The earlier derivation of Chun and Bischoff was dimensionally incorrect. This anomaly has been rectified. The heating of the laser rod has been approximated by considering instantaneous generation of heat on the cylindrical surface.     

Primaquine-mediated oxidative metabolism in the human red cell. Lack of dependence on oxyhemoglobin, H2O2 formation, or glutathione turnover

Stimulation of the hexose monophosphate shunt by primaquine results from the oxidation of NADPH by primaquine. This conclusion was based on the observations that primaquine lowered cellular NADPH but not GSH and that, in red cells in which the GSH was unavailable for reaction, primaquine still stimulated the rate of the hexose monophosphate shunt. In a non-cellular system, primaquine interacted with NADPH, but not GSH, to produce H2O2. Stimulation of the hexose monophosphate shunt by primaquine does not primarily involve H2O2 accumulation since stimulation of the pathway by primaquine was also observed in red cells containing methemoglobin, a red cell preparation in which no H2O2 accumulates. Methemoglobin prevented the formation and/or accumulation of H2O2 in intact red cells incubated with primaquine as well as in a non-cellular system containing primaquine plus Fe2+-EDTA as an H2O2 source. Methemoglobin probably acts by scavenging reactive intermediates since oxyhemoglobin was formed from methemoglobin in the non-cellular experiments. In the red cell, primaquine stimulated glucose-dependent conversion of methemoglobin to oxyhemoglobin.     

Reduction of multivariable systems

A simple procedure is presented for obtaining reduced-order models for linear multivariable systems. It does not require the calculation of the eigenvalues, and the stability of the reduced model is guaranteed if the original system is stable. It generalises the Routh approximation method to the multivariable case.