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This paper reports the use of Laser-induced Forward Transfer (LIFT) technology for printing of multilayer flexible circuitries and the fabrication of micro-bumps for flip-chip bonding of packaged LEDs and bare die microcomponents. Bonding of passive and functional surface mount devices (SMD) on low-temperature polyethylene terephthalate (PET) foils have been demonstrated using two selective bonding techniques. Firstly, using a high intensity near-infrared (NIR) lamp, a bare die NFC chip was bonded on micro-bumps formed with LIFT printed isotropic conductive adhesive (ICA) within less than a minute. Secondly, using a high intensity Xenon lamp, passive components and packaged LEDs were bonded within 5 seconds on microbumps formed with conventional Sn-Ag-Cu (SAC) lead-free alloys. In the both cases, due to selective light absorption, a limited temperature increase was observed in the PET substrates allowing successful bonding of components onto the delicate polyethylene foil substrates using conventional interconnect materials. © 2018 IEEE.

The lead-based complex perovskite Pb(Yb0.5Ta0.5)O3, exhibiting long-range B-site cation ordering has been studied by Raman spectroscopy. The investigation has been performed as a function of temperature ranging from 250 K to a lower temperature 10 K in the spectral range 1020-20 cm-1. The spectra are analyzed through the characteristic parameters: peak position and line width of phonon modes. Significant decrease in the asymmetric phonon line broadening with noticeable shift of the peak positions and appearance of new modes in the Raman spectra at low temperature have been observed. The local distortion in the lattice has been enhanced substantially at low temperature. The splitting of the F2g modes suggests that the orthorhombic phase is stabilized at low temperature. The two F2g modes (60 and 518 cm-1) show soft mode behavior. � 2007 Elsevier B.V. All rights reserved.

We report here on an ecologically friendly carbothermal reduction method to realize SrS:Ce phosphor. The method effectively reduces the preparation temperature by 100 �C. The effect of sulfur and charge compensator were studied separately and in combination, on the luminescent properties of SrS:Ce phosphor prepared from SrSO4:Ce(SO4)2�4H2O using this method without inert gas or hazardous gas (H2S) environment. To analyze the role of charge compensator on the luminescent emission property of SrS:Ce, various fluxes, viz., NH4Cl, NaCl were used. The synthesized products were characterized by XRD, photoluminescence emission and excitation spectroscopy (PLE). SrS:Ce showed a bright blue-green emission at 480 and 540 nm corresponding to energy bands originating from 2T2g (5d) to 2F7/2, 2F5/2 (4f) of Ce3+ transitions. The characterization results showed the formation of SrS calcined at 900 �C for 5 h with an increase in blue-green luminescence intensity after the addition of sulfur and charge compensator, separately. When the sulfur and NH4Cl were jointly added, the intensity of blue emission was enhanced, whereas, that of green emission was suppressed. The excitation spectrum showed a fundamental absorption of SrS host crystal lattice at 283 nm and Ce3+ absorption at 430 nm respectively. The CIE (Commission International de'Eclairge) chromaticity coordinates of the phosphor are also reported. � 2006 Elsevier Ltd. All rights reserved.

This paper deals with the development and validation of a detailed kinetic model for steam reforming of biogas with and without H2S. The model has 68 reactions among 8 gasphase species and 18 surface adsorbed species including the catalytic surface. The activation energies for various reactions are calculated based on unity bond index-quadratic exponential potential (UBI-QEP) method. The whole mechanism is made thermodynamically consistent by using a previously published algorithm. Sensitivity analysis is carried out to understand the influence of reaction parameters on surface coverage of sulfur. The parameters describing sticking and desorption reactions of H2S are the most sensitive ones for the formation of adsorbed sulfur. The mechanism is validated in the temperature range of 873-1200 K for biogas free from H 2S and 973-1173 K for biogas containing 20-108 ppm H2S. The model predicts that during the initial stages of poisoning sulfur coverages are high near the reactor inlet; however, as the reaction proceeds further sulfur coverages increase towards the reactor exit. In the absence of sulfur, CO and elemental hydrogen are the dominant surface adsorbed species. High temperature operation can significantly mitigate sulfur adsorption and hence the saturation sulfur coverages are lower compared to low temperature operation. Low temperature operation can lead to full deactivation of the catalyst. The model predicts saturation coverages that are comparable to experimental observation. � 2013 Elsevier B.V.

A closed-cycle helium refrigerator is utilized for the development of a facility for performing Mossbauer and electrical resistivity studies at low temperatures down to 18 K. This facility includes a vibration isolation assembly in order to isolate the sample holder from the vibrations arising from the cold head of the closed-cycle refrigerator. A top-loading chamber and a set of bellows are used for this purpose. The performance of the system was tested by recording the spectra of natural iron foil at 300 K when the closed-cycle refrigerator was on and when it was off. The typical width of the outer lines of the Fe spectra obtained was 0.26 mm s-1, which indicates the effective isolation of vibration. A facility for electrical resistivity measurements by a four-probe method was also developed for use in the same facility for Mossbauer studies.

The selective catalytic reduction of NO by H2 under strongly oxidizing conditions (H2-SCR) in the low-temperature range of 100-200 °C has been studied over Pt supported on a series of metal oxides (e.g., La2O3, MgO, Y2O3, CaO, CeO2, TiO2, SiO2 and MgO-CeO2). The Pt/MgO and Pt/CeO2 solids showed the best catalytic behavior with respect to N2 yield and the widest temperature window of operation compared with the other single metal oxide-supported Pt solids. An optimum 50 wt% MgO-50wt% CeO2 support composition and 0.3 wt% Pt loading (in the 0.1-2.0 wt% range) were found in terms of specific reaction rate of N2 production (mols N2/gcat s). High NO conversions (70-95%) and N2 selectivities (80-85%) were also obtained in the 100-200 °C range at a GHSV of 80,000 h-1 with the lowest 0.1 wt% Pt loading and using a feed stream of 0.25 vol% NO, 1 vol% H2, 5 vol% O2 and He as balance gas. Addition of 5 vol% H2O in the latter feed stream had a positive influence on the catalytic performance and practically no effect on the stability of the 0.1 wt% Pt/MgO-CeO2 during 24 h on reaction stream. Moreover, the latter catalytic system exhibited a high stability in the presence of 25-40 ppm SO2 in the feed stream following a given support pretreatment. N2 selectivity values in the 80-85% range were obtained over the 0.1 wt% Pt/MgO-CeO2 catalyst in the 100-200 °C range in the presence of water and SO2 in the feed stream. The above-mentioned results led to the obtainment of patents for the commercial exploitation of Pt/MgO-CeO2 catalyst towards a new NOx control technology in the low-temperature range of 100-200 °C using H2 as reducing agent. Temperature-programmed desorption (TPD) of NO, and transient titration of the adsorbed surface intermediate NOx species with H2 experiments, following reaction, have revealed important information towards the understanding of basic mechanistic issues of the present catalytic system (e.g., surface coverage, number and location of active NOx intermediate species, NOx spillover). © 2006 Elsevier B.V. All rights reserved. 72 3-4 240 252 Cited By :101

A 64-element, 1.15mm diameter annular-ring CMUT array was characterized and used for forward-looking IVUS imaging tests. The array was manufactured using low temperature processes suitable for CMOS electronics integration on a single chip. The 43×140µm2 array element has suitable view angle for forward looking imaging around 15MHz center frequency and pulse-echo measurements show nearly 100% fractional bandwidth around 17MHz. For imaging and SNR measurements, RF A-scan data sets from various targets were collected using an interconnect scheme forming a 32-element array configuration. The results demonstrate that annular-ring CMUT arrays fabricated with CMOS compatible processes are capable of forward-looking IVUS imaging. Publisher's Version

This paper presents a novel approach to realize low-cost millimeter-wave modules using only SMD packaged MMICs integrated on a single organic substrate. This approach is demonstrated on a 38 GHz transceiver module for point-to-point LMDS communication systems. The required SMD package technology and demonstrator have been developed in the 5th framework European IST project "Surface Mount Assembly for Communication K-band Systems" (SMACKS). Two types of SMD packages have been developed based on LTCC technology for the low-power devices and an organic package for the high-power amplifier. The use of only packaged devices enables low-cost module manufacturing without the need for specialized equipment and without yield loss from handling bare die MMICs. The estimated cost reduction of such a module, with respect to a module using bare die components and mixed substrate technologies, is around 20%. A disadvantage of this approach is that the density of integration is low, since each active device is housed in its own package.

This paper presents a novel approach to realize low-cost millimeter-wave modules using only SMD packaged MMICs integrated on a single organic substrate. This approach is demonstrated on a 38 GHz transceiver module for point-to-point LMDS communication systems. The required SMD package technology and demonstrator have been developed in the 5th framework European IST project "Surface Mount Assembly for Communication K-band Systems" (SMACKS). Two types of SMD packages have been developed based on LTCC technology for the low-power devices and an organic package for the high-power amplifier. The use of only packaged devices enables low-cost module manufacturing without the need for specialized equipment and without yield loss from handling bare die MMICs. The estimated cost reduction of such a module, with respect to a module using bare die components and mixed substrate technologies, is around 20%. A disadvantage of this approach is that the density of integration is low, since each active device is housed in its own package.

We present a numerical study of the time-dependent and time-independent Gross-Pitaevskii (GP) equation in two space dimensions, which describes the Bose-Einstein condensate of trapped bosons at ultralow temperature with both attractive and repulsive interatomic interactions. Both time-dependent and time-independent GP equations are used to study the stationary problems. In addition the time-dependent approach is used to study some evolution problems of the condensate. Specifically, we study the evolution problem where the trap energy is suddenly changed in a stable preformed condensate. In this case the system oscillates with increasing amplitude and does not remain limited between two stable configurations. Good convergence is obtained in all cases studied., Comment: 9 latex pages, 7 postscript figures, To appear in Phys. Rev. E

Isothermal vapour-phase epitaxy (ISOVPE) was the earliest process to be developed for the fabrication of epitaxial mercury-cadmium telluride layers. Although the process was somewhat neglected in the previous period, mostly because of the appearance of metalorganic chemical vapour phase epitaxy and molecular-beam epitaxy, the results of the most recent investigations show that the application of this method can be expected in the second generation of photovoltaic (PV) or metal-insulator-semiconductor (MIS) detectors in the focal plane. This review paper presents the development of ISOVPE giving a complete theoretical model of the process, which is based on fundamental results in the field of phase diagrams of the (Hg,Cd)Te the interdiffusion of Hg and Cd, gas-phase transport, etc. Using the results of this theoretical model, a production system for ISOVPE was designed, in which the deposition process, the high-temperature annealing for composition homogenization and the low-temperature annealing for the achievement of the desired epitaxial-layer doping are all performed in the same cycle. Finally, the basic electrical and optical characteristics of ISOVPE layers are analysed. It is shown that in applications of the fabrication of PV and MIS detector arrays a full affirmation of this technology can be expected.

The resistivity (ϱ) and thermopower ( S ) of semiconducting phases in the system Bi 2 Sr 2 Ca 1− x Y x Cu 2 O 8+δ and Bi 2 Sr 2− x La x CuO 6+δ have been measured in the temperature ranges 300–700 K and 300–1000 K respectively. The values of ϱ and S at any temperature increase with increase in x . Both systems show thermally activated hopping at low temperatures (300–450 K) with the activation energy increasing with x . The figure of merit ( S 2 σ/λ) peaks to a maximum value of 1.9×10 -5 WK -2 m -1 at x =0.7 in the Bi-2212 system.

We have carried out studies on the effect of oxide additives (Ca0�85Sr0�15CuO2, BaBiO3 and BaPbO3) on Bi-2212. Compositions up to 6 mole% of all the additives have been prepared and characterized by XRD, resistivity and ac susceptibility techniques. XRD studies indicate that all the materials are single phase. Resistivity and ac susceptibility studies indicate enhanced granular behaviour with the oxide additives. Low temperature (400�) sintering results in degradation of the Bi-2212 phase in the presence of the additives. ? 1994 Indian Academy of Sciences.