<span style="font-size:14.0pt;line-height: 115%;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:black;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">Preparation and characterization of Li_1.1Mn₂O₄/polymer electrolyte/graphite cell</span>

345-348Solid state batteries with lithium and an insertion material as active electrode components and a poly (ethylene oxide) based electrolyte, have proven to be feasible alternatives to the classical secondary battery systems. The solid state electrochemical cell Li1.1Mn2O4 |PEO:LiClO4| Graphite was fabricated by sandwiching the thin electrolyte film between the cathode and anode pellets. This sandwich was pressed between suitable current collectors in a spring tight sample holder assembly. The complex impedance of electrolyte and Li1.1Mn2O4 was measured and discharge characteristics were studied for various loads. Also energy densities were calculated. Constant current discharge curves were obtained at several load values. The observed energy density is 47 J/kg for 0.1 M ohm load. The lithium salt content of the polymer electrolyte is found to decrease at the positive electrode whilst increasing at the lithium side. The res ults predict that the critical charge at which the curves deviate should be inversely proportional to the current.</span

Boron isotope distribution in laser deposited thin films of B₄C

131-134Isotope enrichment in laser-ablated plume is an interesting phenomenon. In this work, we have compared the boron isotope distribution present in thin films of B₄C that are formed by pulsed laser deposition using nanosecond (ns) and picosecond (ps) pulse Nd-YAG lasers. With the ns laser beam, in the plume we could observe an isotope ratio of ¹⁰B/¹¹B as high as 0.9, but in the film we could hardly see any enrichment. With ps pulsed laser, the maximum value obtained for the ¹⁰B/¹¹B ratio is about 0.29 in the film

Development of an ion mobility spectrometer for detection of explosives

An ion mobility spectrometer (IMS) is developed for use as an analytical tool and, in particular, for the detection of species used as explosives. From the initial design based on the literature, we have, through several optimization studies, reached a configuration that provides the desired sensitivity with adequate resolution. Results obtained with the optimized geometry are presented in this article. The sensitivity of the instrument is about 10 ng for 2,4,6-trinitrotoluene (TNT) and Royal Demolition Explosive or cyclotrimethylene trinitramine (RDX) and about 50 ng for pentaerythritol tetranitrate (PETN). These explosives are detected as clearly resolved features

Comparison of bulk and pulsed laser deposited thin film of LiCo<SUB>0.85</SUB>Cr<SUB>0.15</SUB>O<SUB>2</SUB> for lithium battery application

LiCo0.85Cr0.15O2 bulk powders are synthesized using combustion process and made into a thin film by depositing on silicon wafer using a pulsed laser ablation technique. A comparative study by SEM (Scanning Electron Microscope), XRD (X-ray diffraction), Infrared spectroscopy and Raman spectroscopy is performed on both bulk and PLD thin films

Fabrication of reflective volume gratings in pulsed-laser-deposition Ti:sapphire waveguides with UV femtosecond-laser pulses

Highly reflective volume Bragg gratings (R~80%) were written in Ti:sapphire planar and channel waveguides fabricated via pulsed-laser deposition (PLD) by exposure to UV (266 nm) femtosecond laser irradiation through suitable phase masks. Large photo-induced refractive index modulations of up to ~1×10-2 ions were observed, which were completely reversible at temperatures of ∼100°C. The dependence of the refractive index modulation on intensity suggests that the mechanism for grating inscription is an one-photon absorption process. Generation of gratings may result from a charge transfer process between the Ti3+ and Ti4+ ions and/or transient localized structural re-arrangements