Abstract: This paper reports on the effects of Ag addition on physical properties of high
temperature superconductors DyBa2Cu3O7-δ (Dy123). A series of the Dy123 - Agx composite was
prepared by solid state reaction method with varying amount of metallic silver (x = 0 – 0.3).
Resistance versus temperature measurement was done using the four-point-probe method in the
temperature range of 79 K to 300 K. Pure DyBa2Cu3O7-δ was found to superconduct with Tc onset of
91 K and Tc zero of 78 K. Addition of Ag at x = 0.05 caused both Tc onset and Tc zero to increase to 93
K and 84 K, respectively. However, Tc onset and Tc zero dropped for higher silver contents. We found
that the optimum silver content in DyBa2Cu3O7-δ for best superconducting behavior and hardness is
between x = 0.05 and 0.10. Microstructure analysis using SEM and EDAX showed that most of the
silver is uniformly distributed along the grain boundaries filling the pores and hence increasing the
hardness of the samples.
Abstract: Polycrystalline samples of La0.67Ba0.33(Mn1-xRux)O3 with x = 0, 0.05, 0.1, 0.15 and 0.2
have been prepared using solid state reaction. The effects of doping of Ru at Mn site on La-Ba-Mn-
O ceramics, the characteristics and magnetotransport properties of CMR materials are investigated.
The magnetoresistance (MR) effect is measured using the four point probe technique. The
magnetoresistance defined as MR% = (Ro – RH)/RH x 100% was measured at a magnetic field of H
≤ 1T at 90K, 100K, 150K, 200K, 250K, 270K and 300K for the sample of doping x = 0, 0.05, 0.1,
0.15 and 0.2. Overall, MR drops slowly when temperature rises. All doping concentration gives
small variation range (~2.7% to ~26.78%). The electrical property has determined by using
standard four-point probe resistivity measurement in a temperature range of 30 K to 300 K. Metalinsulator
transition temperature (Tp) shifted to lower temperatures as Ru doping is increased. In this
paper the structural pattern and microstructure property have investigated via XRD. XRD patterns
show that these systems are in orthorhombic distorted perovskite structures.
Abstract: Corrosion protection is one of the important performance properties of organic coatings.
In this study, an attempt has been made to develop a high temperature coating. Different
compositions of silicone and polyester resins are taken and mixed well with the addition of a
hardener. The binder system is applied on the pre-treated cold rolled steel panels. Physical and
mechanical properties are evaluated. Thermal resistance of the coating system is done according to
specification of ASTM D2485 standards. DSC and TGA analyses are carried out to study the glass
transition temperature and temperature dependence of the sample prepared respectively. Corrosion
protection ability of the system is evaluated by electrochemical impedance spectroscopy (EIS) and
immersion studies. From the thermal studies, the coating containing 40% silicone and 60%
polyester has withstood up to 498 K.
Abstract: We have studied on the use of a GaN powders for growing gallium oxide (Ga2O3)
nanoribbons and nanosheets by the thermal evaporation technique. We used x-ray diffraction,
scanning electron microscopy, and transmission electron microscopy to characterize the samples. The
results showed that the produced Ga2O3 nanomaterials had single crystalline monoclinic structures.
The proportion of wider nanoribbons or nanosheets to nanoribbons increased by increasing the
growth temperature and by employing the mixture of GaN and ZnO powders.
Abstract: This paper presents an analysis of diamond-like carbon thin film deposited using
homebuilt microwave chemical vapor deposition. Two different deposition conditions were
investigated, namely, with and without microwave power. Post deposition analysis included Raman
spectroscopy, scanning electron microscope (SEM), energy dispersed X-ray (EDX), four-pointprobe
resistivity measurements and refractive spectroscopy. Substrate with pretreatment was
observed to have thin film formation. Samples with diamond paste pretreatment show better quality
compared to SiC treated samples as suggested by Raman spectral. The presences of sp3 and sp2
peaks were identified in the Raman spectral. The overall resistivity is low due to the graphite
Abstract: In this paper we report on the characteristics of Pd/GaN and Pd/Si Schottky barriers
exposed to different gases at various temperature range from 25°C to 500°C. The characteristics of
Pd/GaN and Pd/Si Schottky barriers as gas sensors were measured as a function of temperature and
ambient. Both types of sensor show changes in forward current upon introduction of different gases
(N2, air, H2) into the ambient. The devices can be operated at large forward current, leading to large
signal size for current at short response time for switching from one gas ambient to another such as
N2 to H2 (2%) in N2. The signal size increases with the increase in measurement temperature due to
more efficient cracking of the gas molecules. Both types of devices appear well suited to
combustion control and leak detection.
Abstract: The molecular organization of the phospholipids Langmuir-Blodgett (LB) films on solid
substrates has been studied via Fourier Transform Infra Red (FTIR) spectroscopy. In this study, the
formation of well organized ultra thin LB films of phospholipid molecules has been performed by
depositing the monolayer onto the solid substrates of silicon wafer. The space filling molecular
models of two types of phospholipids have been proposed on the basis of the FTIR spectra.
Abstract: In this paper, we report on the characterization of a set of MOCVD grown GaN
samples with a variety of structural or crystalline quality. X-ray diffraction (XRD) was used to
observe the change of the crystalline structure with deposition temperature. All results show that
the structure type of the GaN deposited films is sensitive to the growth temperature. Our results
also revealed that a good crystalline structure of GaN films could be grown at temperatures higher
than 600°C. Finally, a general picture on the correlations between the growth temperature and the
GaN deposited films crystalline is reported.
Abstract: SiO2 -TiO2 glass fibers have been prepared via dry spinning of the viscous solutions of
polytitanosiloxanes followed by steam treatment and pyrolysis at 500, 700, and 900 °C for 1 h
under ambient condition. The polymer was prepared via polycondensation of partially hydrolyzed
tetraethoxysilane (TEOS) and an acetylacetone-chelated titan compound at various H2O/TEOS and
Si/Ti ratios. Gel fibers formed shown tensile strength as low as 200 MPa and increased around 3
times after pyrolysis. The higher degree of TEOS hydrolysis the higher tensile strength of the
fibers. The polymer with higher Si/Ti ratio also provided stronger fibers due to more extensive
siloxane network. Fibers with the highest tensile strength, 610 MPa, was obtained from the
polymer synthesized with SiO2/TiO2 mol ratio 20 and pyrolysis temperature 700 °C.
Abstract: We have synthesized the film-like and rod-like structures of indium oxide (In2O3) by
metalorganic chemical vapor deposition (MOCVD) method. The structural morphology of the
deposits changed from the film to the arrays of 1-dimensional (1-D) materials with increasing the
deposition temperature. The 1-D materials with the serrated surfaces prepared at 350°C possessed a
crystalline cubic structure and had preferentially grown along the  direction.