Showing papers by "University of Hyderabad published in 1982"
TL;DR: In this paper, the problem of defining Cauchy sequence and completeness in quasi-pseudo-metric spaces was considered, and the definitions proposed allow versions of such classical theorems as the Baire Category Theorem, the Contraction Principle and Cantor's characterization of completeness to be formulated in the quasi-semi-measure setting.
Abstract: This paper considers the problem of defining Cauchy sequence and completeness in quasi-pseudo-metric spaces. The definitions proposed allow versions of such classical theorems as the Baire Category Theorem, the Contraction Principle and Cantor's characterization of completeness to be formulated in the quasi-pseudo-metric setting.
164 citations
TL;DR: The theory of second harmonic generation at a metal surface was developed in this paper, when surface plasmon-polaritons are resonantly excited by the incident electromagnetic field.
97 citations
TL;DR: The theory of coherent anti-Stokes Raman scattering (CARS) is extended to include the effect of pump fluctuations in this article, and the intensities and spectra of lines in resonant CARS are calculated to all orders in fields assuming a phase-diffusion model for waves at the two pump frequencies.
Abstract: The theory of coherent anti-Stokes Raman scattering (CARS) is extended to include the effect of pump fluctuations. The intensities and spectra of lines in resonant CARS are calculated to all orders in fields assuming a phase-diffusion model for waves at the two pump frequencies. The bandwidth of the two lasers enters in a much more complicated way than following a simple scaling of ${T}_{1}$ or ${T}_{2}$. Various resonances in CARS spectra due to dynamic splitting of the energy levels are discussed for a range of detunings, field intensities, and bandwidths. In contrast to the usual spectra in strong fields, the Rabi sidebands appear as dispersion-shaped structures. The laser linewidth is shown to change dramatically the CARS line shape. The case of no saturation is also treated, thus allowing for the inclusion of more general line shapes and fluctuations of the pump waves and the nonlinear susceptibility tensor ${\ensuremath{\chi}}^{(3)}$. Gaussian statistics of the pump field are shown to lead to enhancement factors in CARS intensity, similar to those appearing in the context of multiphoton absorption processes.
34 citations
TL;DR: In this paper, a theory relating to correction of distortions that may be achieved by phase conjugation is developed on the basis of the first Born approximation, and it is shown that, to good accuracy, the effect of a distorting medium on an incident wave is eliminated by phase-conjugation if the following conditions are satisfied: the incident field contains no evanescent components, the transmitting medium is a weak, nonabsorbing scatterer, and backscattering of the incident and of the conjugate wave and also the effects of scattered evanescence waves
Abstract: A theory relating to correction of distortions that may be achieved by phase conjugation is developed on the basis of the first Born approximation. It is shown that, to good accuracy, the effect of a distorting medium on an incident wave is eliminated by phase conjugation if the following conditions are satisfied: the incident field contains no evanescent components, the transmitting medium is a weak, nonabsorbing scatterer, and backscattering of the incident and of the conjugate wave and also the effects of scattered evanescent waves are negligible.
32 citations
TL;DR: In this article, it was shown that hexamethylenetetramine (Hmta) acts only as a bidentate ligand bridging between two metal ions retaining the chair configuration of the uncoordinated molecule in all these complexes.
30 citations
TL;DR: In this paper, the photoacoustic technique has been applied for the first time to study the energy gap variation of mixed semiconducting Se1−xTex alloys as a function of x.
21 citations
TL;DR: Amorphous Fe40Ni40B20 (VITROVAC 0040) alloy has been investigated using 57Fe Mossbauer Spectroscopy as discussed by the authors, and the Curie temperature Tc is found to be well defined and is 695 ± 1 K.
18 citations
TL;DR: It could clearly be seen that between the ages of 225 and 750 days there was a second bout of DNA accumulation in the regions examined, and it is presumed that these enzymes, although degradative in nature, must be playing some important role in the synthesis of DNA itself.
15 citations
TL;DR: In this paper, the effect of resonant excitation of surface-plasmon polaritons of a general metal substrate on the relatively long-range classical enhancement of the surface-enhanced Raman scattering is considered.
Abstract: The effect of resonant excitation of surface-plasmon polaritons of a general metal substrate on the relatively long-range classical enhancement of the surface-enhanced Raman scattering is considered. It is shown that all the three factors in the classical enhancement arising from the presence of the metal, namely the local electric field at the molecular site at the incident frequency, the electrodynamic renormalization factor for the molecular polarizability, and the propagator for the Stokes scattered field, are modified resonantly. However, their individual impact on the total enhancement differs appreciably, depending strongly on the shape of the metal surface and the distance of the molecule from the surface. As an example, explicit results are given for a molecule adsorbed on a small sphere.
15 citations
TL;DR: In this paper, the isostructural γ-FeOOH is treated with organic bases at temperatures of 120-140°C and it is quantitatively converted to the topotactically related γ -Fe 2 O 3.
14 citations
TL;DR: In this article, the absolute thermoelectric powers of three glassy ferromagnetic metals Fe40Ni40P14B6, Fe29Ni49P 14B6Si2 and Fe74Co10B16 have been determined between 77 K and 700 K. The results are interpreted in terms of Grest and Nagel theory.
TL;DR: The possibility of a system driven far from equilibrium to exhibit multicritical phenomena is discussed in this article, where the laser oscillating in two modes is shown to possess bicritical and tetracritical points depending on the strength of the coupling between the two modes.
Abstract: The possibility of a system driven far from equilibrium to exhibit multicritical phenomena is discussed. As an example, the laser oscillating in two modes is shown to possess bicritical and tetracritical points depending on the strength of the coupling between the two modes. The phase diagrams indicating the regions and the nature of the four possible phases for the two-mode laser model are presented. The exponents and the scaling characteristics near the bicritical and tetracritical points are also discussed.
TL;DR: In this paper, the magnetic moments, electronic and photoacoustic spectra of coordination compounds formed by the interaction of manganese(II) chloride, thiocyanate, acetate and sulphate with 2,2-bipyridyl (2,2′-Bipy), 4,4′- bipyrithmide (4, 4′-βidyl) and their dioxides have been characterized by electron spin resonance and optical absorption spectral studies in solid and solution states.
TL;DR: Using a relatively recent technique, photoacoustic spectroscopy (PAS), purple pigmentation in leaves of three species of Euphorbia was characterized as anthocyanin by observing a peak at 545 nm.
Abstract: Using a relatively recent technique, photoacoustic spectroscopy (PAS), purple pigmentation in leaves of three species of Euphorbia was characterized as anthocyanin by observing a peak at 545 nm. The in vivo chlorophylls of the leaf have a recorded maximum absorption peak at 675 nm as against 665 nm of the in vitro chlorophylls. The intensity of purple pigmentation in leaves of Euphorbia hirta L., are inversely correlated to the soil moisture levels, leaf water content and leaf water potentials. The applicability of PAS to biological samples was discussed.
TL;DR: In this paper, the Maki-Thompson theory has been compared with the Aslamazov-Larkin, Maki Thompson and Patton theories and it was found that among three, the M-T theory gave a better fit to experimental data.
TL;DR: From low-temperature Mossbauer measurement on FeC2O4·2D2O the reported difference in quadrupole splitting from the simple dihydrate is inferred to be due to lattice effects as discussed by the authors.
Abstract: From low-temperature Mossbauer measurement on FeC2O4·2D2O the reported difference in quadrupole splitting from the simple dihydrate is inferred to be due to lattice effects. The Zeeman split spectrum has been analyzed taking into account the ‘ambiguity problem’ and the hyperfine parameters were determined to be I.S.=1.22 mm/sec; Q.S.=1.93 mm/sec; η=0.65 to 0.72; θ=90 to 83.1o and ϕ=0 to 11.8o. The principal electric field gradient axis lies along the crystal a-axis with VYY and\(\mathop H\limits^ \to\) lying along the crystal b-axis. The crystal field parameters 10Dq, Ds and Dt have been determined to be ∼ 10500, ∼ 185 and ∼ 211 cm−1, respectively.
TL;DR: The results suggest that PEP carboxylase and RuBP car boxylase are localized in the cytoplasm of mesophyll cells and bundle sheath chloroplasts respectively.
TL;DR: It is concluded that the two DNases, whatever their actual physiological role might be, are synthesized in a preferential manner during the rehabilitation.
Abstract: The effect of early postnatal undernutrition and subsequent rehabilitation on wet weight, DNA, RNA, protein, and the activities of acid and alkaline DNases in white and grey matter region of rat brain was studied. In respect to the various parameters studied, white matter was found to be markedly vulnerable to undernutrition, but the grey matter region was unaffected. It has also been observed that the earlier the initiation of nutritional rehabilitation (10th postnatal day) the better was the recovery of the white matter to a normal condition, and in some cases early nutritional rehabilitation resulted in better than normal biochemical composition of the region. The specific activity of acid DNase was unaffected by weanling undernutrition in both white and grey matter. The total activity of this enzyme, which was significantly reduced in white matter of undernourished animals, exhibited a remarkable recovery following rehabilitation, to more than normal levels at 150 days of age. Total activity of alkaline DNase was reduced only in 15-day-old white matter of deprived animals, and here also rehabilitation brought back this enzyme to significantly more than normal levels. It is concluded that the two DNases, whatever their actual physiological role might be, are synthesized in a preferential manner during the rehabilitation.
TL;DR: Results show that LHRH acts directly on the testis and influences the levels of ODC in the Leydig cells of rat, and it is found that ODC activity increases following intratesticular injection with luteinizing hormone releasing hormone.
TL;DR: In this article, the existence of multistability in a system with a complex order-parameter equation of the form $\stackrel{\ifmmode \dot{}\else \.
Abstract: The existence of multistability in a system with a complex order-parameter equation of the form $\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{\ensuremath{\psi}}=y\ensuremath{-}\ensuremath{\psi}Q({|\ensuremath{\psi}|}^{2})$ is examined, with special reference to optical systems such as multiphoton and multimode lasers. It is shown that the neglect of the phase of the order parameter from the dynamical considerations could lead to a different type of multistable behavior. The general polynomial form of $Q$ for the existence of tristability is obtained.
TL;DR: Conformational similarity among amino acid residues, a property derived by analysing (phi, psi)-probability distributions of 20 proteinous amino acids from 38 different globular proteins, is used to arrive at a set of six 'obligatory' amino acids of primitive proteins.
Abstract: Conformational similarity among amino acid residues, a property derived by analysing (phi, psi)-probability distributions of 20 proteinous amino acids from 38 different globular proteins, is used to arrive at a set of six 'obligatory' amino acids of primitive proteins. The amino acids Ser, Val, Leu, Asp, Gly and Pro have been argued to be 'obligatory' and to represent, conformationally, the remaining amino acids. The reasons for consideration of these six residues as 'obligatory' are discussed. Methods to check the validity of our proposition are suggested.
TL;DR: In this paper, a cumulant expansion for the two-time correlation functions for linear stochastic differential equations is presented, and the resulting equations become exact in the second order approximation in the scalar gaussian case.
TL;DR: In this article, the authors considered the case of partially coherent optical sources whose amplitudes are weakly modulated at a low frequency and showed that the shape of the fluorescent signal is extremely sensitive to the bandwidth of the field.
Abstract: The fluorescence emitted by atoms whose excited states have Zeeman structure is studied for the case of excitation by partially coherent optical sources whose amplitudes are weakly modulated at a low frequency $\ensuremath{\Omega}$. The temporal fluctuations in lasers are taken into account exactly by using the phase-diffusion model of the laser. Analytical results for the modulated fluorescence are presented for the case of weak fields. It is shown that the shape of the fluorescent signal is extremely sensitive to the bandwidth of the field; for example, one gets resonances at a Larmor frequency equal to $\mathcal{s}=\frac{\ifmmode\pm\else\textpm\fi{}\ensuremath{\Omega}}{2}(0,\ifmmode\pm\else\textpm\fi{}\ensuremath{\Omega})$ for broadband (monochromatic) fields. Various limiting cases are treated, and in the limit of very broadband fields, results reduce to those of Corney and Series. The fluorescence is studied both as a function of the modulation frequency and as a function of the magnetic field. Numerical studies of the modulated Hanle signals in intense fields reveal resonant structures in the modulation-frequency scan at $\ensuremath{\Omega}=0,\ifmmode\pm\else\textpm\fi{}{\ensuremath{\alpha}}_{0}$, $\ifmmode\pm\else\textpm\fi{}2{\ensuremath{\alpha}}_{0}({\ensuremath{\alpha}}_{0}^{2}={\mathcal{s}}^{2}+2{\ensuremath{\alpha}}^{2})$ due to the dynamical Stark splitting of the various energy levels, with the strength of the resonances depending on the direction of detection.
01 Jan 1982
TL;DR: Water-in-oil (w/o) microemulsions consist of spherically dispersed water droplets confined inside a continuous oil phase by an interfacial sheath of a surfactant-cosurfactant mixture as mentioned in this paper.
Abstract: Water-in-oil (w/o) microemulsions consist of spherically dispersed water droplets confined inside a continuous oil phase by an interfacial sheath of a surfactant-cosurfactant mixture. Use of the cosurfactant allows one to adjust the hydrophile-lipophile balance such that a variety of surfactants, in particular non-ionics, can be used to prepare w/o microemulsions with ease. Often, when the water content is increased to above 10%, the system changes phase to produce multi-bilayer liquid crystalline lamellae. Hydrodynamic, optical absorption and emission, and magnetic resonance spin relaxation investigations on a typical system, i.e. Triton X-100, hexanol, water, and cyclohexane w/o microemulsions, suggests a similarity of microstructural features with reverse micelles. The initially added water is strongly bound to the surfactant and as the water content is increased, the amount of ‘free’ water increases. Globular proteins and enzymes have been solubilized inside the water pools of these w/o microemulsions with retention of native conformation and enzyme, activity. W/o microemulsions can thus be used as suitable models for studying biopolymer structure and function in restricted environments such as those of biological cellular interiors.
TL;DR: In this paper, a model of mixed valence was proposed in which transfer of an electron from an occupied orbit of a ligand to an empty orbit of an ion by electron-phonon interaction causes the change in valency.
01 Jan 1982
TL;DR: In this paper, a revised version of part of the lectures given by the author at Trieste Seminar on Complex Analysis and its Applications is presented, along with a report on the results obtained by Girbau-Haefliger-Sundararaman subsequent to the Seminar.
Abstract: This is a revised version of part of the lectures given by the author at Trieste Seminar on Complex Analysis and its Applications. The last part of this paper gives a report on the results obtained by Girbau-Haefliger-Sundararaman subsequent to the Seminar. The author would like to thank Professor A. Haefliger for his suggestions. The remaining part of the lectures of the author has appeared in [58]. The author thanks Centro de Investigacion del I.P.N., Mexico City, for hospitality during the writing of the paper.
TL;DR: In this article, a model calculation for radiation from planar channeled electrons at relativistically high energies has been performed using an analytical planar potential and the expressions for energies of the emitted radiations found in analytical form.
TL;DR: In this paper, the radial dependence of Sternheimer quadrupole shielding-antishielding factor is reported for He, Ne, Ar and Kr atoms at the coupled Hartree-Fock level of accuracy.
Abstract: The radial dependence of Sternheimer quadrupole shielding-antishielding factor is reported for He, Ne, Ar and Kr atoms at the coupled Hartree-Fock level of accuracy. The results would be useful in the interpretation of the nuclear quadrupole interactions measured at the rare gas nuclei in different chemical environment such as the various van der Waals molecules.