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Pressure and temperature dependent Raman scattering studies on Ho2O3 have been carried out to investigate the structural transition and the anharmonic behavior of the phonons. Ho2O3 undergoes a transition from cubic to monoclinic phase above 15.5 GPa, which is partially reversible on decompression. The anharmonic behavior of the phonon modes of Ho2O3 from 80K to 440K has been investigated. We find an anomalous line-width change with temperature. The mode Grüneisen parameter of bulk Ho2O3 was estimated from high pressure Raman investigation up to 29 GPa. Furthermore, the anharmonic components were calculated from the temperature dependent Raman scattering. [ABSTRACT FROM AUTHOR]

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Room temperature ferromagnetism is observed in Zn1-xCuxO (x=0.01, 0.03, and 0.05) thin films grown on Al2O3 substrates by pulsed laser deposition technique. Raman scattering and high resolution transmission electron microscopy analyses confirm the substitution of Cu up to 3% in ZnO host lattice, and the films are nearly single crystalline. Optical transmission and photoluminescence (PL) analyses provide evidence of sp-d exchange interaction in Zn1-xCuxO thin films; the p-d exchange interaction may explain the observed room temperature ferromagnetism in Zn1-xCuxO thin films. Room temperature PL shows the green emission (∼2.60 eV) in Cu doped ZnO samples. [ABSTRACT FROM AUTHOR]

The "isospin-phonon" coupling in Sr2IrO4 is investigated by temperature dependent phonon Raman scattering. Anomalous behavior in the frequency of all studied optical phonons is observed below the magnetic transition temperature TN ∼ 240 K. The strongest effect is detected for the A1g mode at 272 cm−1 associated with the modulation of the Ir–O–Ir bond angle. Additionally, the A1g mode at 560 cm−1 shows a Fano asymmetric lineshape sensitive to TN, supporting the existence of low energy (∼70 meV) electronic excitations that are renormalized by the magnetic order. These results reveal the characteristics of the interaction between the crystal lattice and electronic degrees of freedom in this "spin-orbit" entangled Mott insulator. [ABSTRACT FROM AUTHOR]

In this note, we have obtained some novel results on trilateral generating functions involving Ynα+nk, a modified form of Konhauser biorthogonal polynomials, {Ynα(x; k)} with Tchebycheff polynomials by group theoretic method. As special cases, we have obtained the corresponding results on Lagurrepolynomials. [ABSTRACT FROM AUTHOR]

The nanocrystalline rare earth sesquioxides Dy2O3, Gd2O3 and Y2O3 have been investigated for anharmonic effects in the temperature range 80-440 K using Raman spectroscopy. These samples were cubic in structure under ambient conditions with particle sizes in nano-range. The predominant Tg + Ag phonon modes of the samples primarily exhibited phonon softening in the investigated temperature range. However, the line width variations clearly reflected the variations in the effects of anharmonicity on these samples, and the related anharmonic constants were estimated. The mode Grüeneisen parameters required for these studies were deduced from our own high-pressure data for these samples reported earlier. The line width variations for these samples were found to display similar trends; however, their magnitudes were indicative of the factors that are expected to contribute to the variation in phonon behaviour. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper we have obtained some novel generating functions of 2F1 (-η, α γ + n; x) - the modified form of Hypergeometric polynomials 2F1 (-η, α γ x) by utilizing L. Weisner's group-theoretic method of obtaining generating functions. In section-2, we obtain a set of infinitesimal operators by giving suitable interpretations to both the index (n) and the parameter (γ) of the polynomial under consideration, known as raising and the lowering operators has been introduced and on showing that they generate a four dimensional Lie algebra, we have obtained, in section-3, a novel generating functions of the Hypergeometric polynomials which in turn yields a number of new and known results on generating functions. [ABSTRACT FROM AUTHOR]

Fire resisting property was imparted to cellulosic paper by the application of a bio-enriched version of a banana pseudostem sap (BPS) as well as the only BPS, obtained as a byproduct during fibre extraction from the pseudostem. The papers were evaluated for their flame retardant property by measurement of limiting oxygen index and vertical flammability. They were also characterized by thermogravimetry, scanning electron microscopy and energy dispersive X-ray analysis. The bio-enriched BPS treated paper was found to exhibit a better flame retardancy with distinguished char length, compared to the control and the only BPS treated paper. The impartment of flame resisting property to a paper by the BPS, along with its charring behaviour has been discussed and the mechanism thereon has been postulated. The BPS application was found to enhance the oxygen required for the burning of the paper and reduce its burning rate by promoting more dehydration and char formation. The imparted fire retardant finish found durable to weathering, did not cause any significant loss in tear and tensile properties of the paper. [ABSTRACT FROM AUTHOR]

In this note, we have obtained a novel extension of a bilateral gen- erating relations involving modified Gegenbauer polynomials, Cλ+nn (x) from the existence of quasi-bilinear generating relation by group-theoretic method. [ABSTRACT FROM AUTHOR]

In this paper, we have presented a unified theory of obtaining a novel class of bilateral generating relations involving certain special functions by group theoretic method. In Section 2, the method has been fully discussed and finally we have arrived at a conclusion in connection with the unification of a class of bilateral generating functions involving some special functions which is stated in Theorem 2.1. In Section 3, we have obtained a good number of theorems on bilateral generating functions involving various special functions in course of application of Theorem 2.1 obtained in this investigation. [ABSTRACT FROM AUTHOR]

This article investigates the effect of dielectric thickness and ground width on the performance of multilayer conductor backed coplanar waveguide lumped elements and circuits fabricated on advanced multilayer photoimageable thick-film ceramic multichip module (MCM) technology. From the S-parameters, the effective dielectric constant is extracted to investigate the effect of dielectric thickness and ground-width on transmission line dispersion. The equivalent circuit parameters for multilayer ceramic-based capacitors and inductors are investigated for various dielectric thicknesses and ground-plane widths. Finally, the practical effect of dielectric thickness and ground width are investigated for a highly compact and high performance lumped element low pass filter at 3 GHz, developed for cost-effective MCM applications. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1127-1132, 2012 [ABSTRACT FROM AUTHOR]

The Cu and Mn co-doped ZnO dilute magnetic semiconductor Zn1-x(Cu-Mn)xO films with unique nanoneedle like structure were deposited at ≤300°C by a two step closed space flux sublimation and periodic oxidation method. Morphology studies establish complex growth process involving a eutectic metal condensate on the substrate and spontaneous emergence of nanoneedle structure by oxidative process controlled by the vapor-liquid-solid mechanism. X-ray diffraction studies show that Zn1-x(Cu-Mn)xO films retain the typical wurtzite hcp structure of the un-doped ZnO. The absence of extraneous reflections indicates that neither the Mn and Cu dopant metal clusters nor their oxide phases are included in the nanostructure Zn1-x(Cu-Mn)xO films. The Raman peaks of Zn1-x(Cu-Mn)xO nanocrystalline films are consistent with the Raman active phonon modes for ZnO. The red shifted E2 (Low) and E2 (high) peaks confirm that Mn and Cu substitute at Zn site in the nanostructure Zn1-x(Cu-Mn)xO films. Optical transition at direct band gap energy occurs at 3.11 eV and an upward energy shift in the direct band to 3.58 eV is assigned to the quantum size effects of the nanoneedle structure of Zn1-x(Cu-Mn)xO films. [ABSTRACT FROM AUTHOR]

A macrokinetic study on the bioconversion of hexavalent chromium present in tannery waste was carried out using chemostat as a contacting device. Two monocultures viz. Pseudomonas sp. and Bacillus sp., isolated and purified from native source, were used as biocatalysts. Although bioconversion of Cr+6 to Cr+3 is not strictly an enzyme process, it was observed that the global conversion equation for this complex biotic-abiotic process follows Monod's substrate uninhibited model equation. [ABSTRACT FROM AUTHOR]

The design, fabrication and performance of a 60-GHz multi-chip module receiver employing a substrate integrated waveguide filter and antenna are presented. The receiver is integrated onto a single multilayer substrate, fabricated using photo-imageable thick-film technology. The module incorporates a GaAs monolithic microwave integrated circuit low-noise amplifier and downconverter, with lumped elements for intermediate frequency (IF) filtering embedded into the substrate. The chip cavities for mounting of the MMICs are photo-imaged as part of the standard process, giving precise dimensional control for short bond-wire lengths. The complete module including integrated antenna measures only 22.5 mm×5.4 mm×0.3 mm and works from 58 to 64 GHz. [ABSTRACT FROM AUTHOR]

The lower hybrid current drive (LHCD) system is an important system in superconducting steady state tokamak (SST-1). It is used to drive and maintain the plasma current for 1000 s with a duty cycle of 17%. The LHCD system is being designed to launch 1 MW of radio frequency (rf) power at 3.7 GHz. The rf source is comprised of two high power klystron amplifiers, each capable of delivering 500 kW rf power. In this article, the results obtained during installation and commissioning of these klystrons are presented. Two klystrons (model TH2103D) have been successfully installed and commissioned on dummy loads, delivering ∼200 kW power for more than 1000 s. The maximum output power that could be obtained is limited due to the available direct current (dc) power supply. The test system is comprised of a TH2103D klystron, a low power rf (3.7 GHz/25 W) source, two high power four port circulators, two high power dual directional couplers, two arc detector systems, and two dummy water loads. To avoid rf breakdown in the rf components of the transmission line, the system has been pressurized with dry air to 3 bar. To energize and operate the klystron, a high voltage dc power supply, a magnet power supply, an ion pump power supply, a -65 kV floating anode modulator power supply, and a filament power supply are used. An arc detector unit has been installed to detect and initiate action within a few microseconds to protect the klystron, waveguides, and other rf passive components during arcing. To protect the klystron in the event of an arc, a fast responding (<10 μs), rail gap based pressurized crowbar unit has been used. The entire system is water cooled to avoid excess temperature rise during high power continuous wave operation of the klystron and other rf components. The tube requires initial conditioning. Thereafter, the output rf power is studied as a function of beam parameters such as cathode voltage and beam current. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A guanidiniocarbonyl pyrrole (GCP) cation forms stable H-bond assisted ion pairs with carboxylates even in aqueous solutions. A tetra GCP cation 1 undergoes efficient two-component self-assembly with Na4EDTA, a tetra-carboxylate, leading to 3D supramolecular networks. These networks show dual pH responsiveness and reversibly dissociate back into monomers upon addition of either acid or base. [ABSTRACT FROM AUTHOR]

(In1-xFex)2O3 polycrystalline samples with x=(0.0,0.05,0.10,0.15,0.20, and 0.25) have been synthesized by a gel combustion method. Reitveld refinement analysis of x-ray diffraction data indicated the formation of single phase cubic bixbyite structure without any parasitic phases. This observation is further confirmed by high resolution transmission electron microscopy imaging, indexing of the selected-area electron diffraction patterns, x-ray absorption spectroscopy, and Raman Spectroscopy. dc magnetization studies as a function of temperature and field indicate that they are ferromagnetic with Curie temperature (TC) well above room temperature. [ABSTRACT FROM AUTHOR]

The multi phonon Raman scattering in Mn doped (1%–10%) ZnO was observed at room temperature using 514.5 nm Ar+ laser. The additional optical modes at 327, 332, 482, 532, and 680 cm-1 in Zn1-xMnxO targets were identified as the second order Raman modes in the disordered lattice and the precipitation of the secondary phase ZnMn2O4. The crystalline grain sizes of 1%, 3%, 5%, and 10% Mn doped ZnO samples were calculated by phonon confinement model as 31.8, 18.3, 15.9, and 14.1 nm, respectively. The optical band gap was found to be increased (3.27–3.41 eV) due to the Mn doping. [ABSTRACT FROM AUTHOR]

Amorphous and crystalline thin films of Mn-doped (0.5 %–10%) GaAs and crystalline thin films of Zn1-xCox, O(x=3%–20%) were investigated by means of magnetic susceptibility and electron spin resonance (ESR). For the Mn-doped GaAs samples, our results show the absence of ferromagnetic ordering for the amorphous films in the 300 > T > 2 K temperature range, in contrast to the ferromagnetism found in crystalline films for TC <110 K. A single ESR line with a temperature independent g-value (g ∼ 2) is observed for the amorphous films, and the behavior of this ESR linewidth depends on the level of crystallinity of the film. For the Mn-doped GaAs crystalline films, only a ferromagnetic mode is observed forT < Tc when the film is ferromagnetic. Turning now the Zn1-xCox,O films, ferromagnetic loops were observed at room temperature for these films. The magnetization data show an increasing of the saturation magnetization Ms as a function of x reaching a maximum value for x ≈ 10%. ESR experiments at T = 300 K in the same films show a strong anisotropic ferromagnetic mode (FMR) for x = 0.10. [ABSTRACT FROM AUTHOR]

Thin films of Zn1-xCoxO (x=1–15%) were grown on an Al2O3 (0001) substrate by pulsed laser deposition and characterized by investigating their photoluminescence (PL) and other optical properties. The films were highly (0001) oriented without any impurity phases as observed in x-ray diffraction. The optical transmittance spectra showed that the band edge of Zn1-xCoxO was decreased with increase of Co concentration along with a subbandgap absorption in the range of 1.8 to 2.2 eV. The near band-edge PL spectrum of ZnO thin films at 77 K showed a strong peak of donor bound exciton at 3.307 eV along with the free excitons. However, the PL spectra for free excitons of the Zn1-xCoxO films at 77 K did not show any significant redshift due to Co incorporation. [ABSTRACT FROM AUTHOR]

A compact 60 GHz MCM receiver has been demonstrated by integrating millimetre-wave substrate-integrated waveguides and GaAs MMICs for the first time. The module includes a waveguide antenna and filter, MMIC LNA and mixer, and lumped elements for IF filtering embedded into the multilayer photo-imageable thick-film substrate. Cavities for MMIC attachment are photo-imaged as part of the standard process. [ABSTRACT FROM AUTHOR]

Local vibrational modes (LVMs) and asymmetric phonon lineshapes are investigated in ZnO : Sb system. Two LVMs at 186 and 235 cm−1 originating due to the change in reduced mass and reduction of localized interatomic force constant have been identified. Upon Sb-doping, the E1(LO) mode of ZnO was found to shift towards the lower frequency side and broaden asymmetrically. These results are analysed within the framework of the Fano interaction in p-type ZnO. Temperature dependence of the E1(LO) mode frequency and line width shows the conventional anharmonic behaviour in ZnO; whereas, it deviates in ZnO : Sb system. In addition, the carrier–phonon coupling strength was found to reduce at higher temperature. [ABSTRACT FROM AUTHOR]