Influence of Sm2O3 doping on formation and structure of SrBi2Nb2O9 nanocrystals in lithium borate glasses

New glasses of 16.66SrO–16.66[(1 − x)Bi2O3–xSm2O3]–16.66Nb2O5–50Li2B4O7 (0 ≤ x ≤ 0.5, in molar ratio), i.e., the pseudo-binary Sm2O3-doped SrBi2Nb2O9–Li2B4O7 glass system, giving the crystallization of Sm3+-doped SrBi2Nb2O9 nanocrystals are developed. It is found that the thermal stability of the glasses against the crystallization and the optical band gap energy increases with increasing Sm2O3 content. The formation of fluorite-type Sm3+-doped SrBi2Nb2O9 nanocrystals (diameters: 13–37 nm) with a cubic structure is confirmed in the crystallized (530 °C, 3 h) samples from X-ray powder diffraction analyses, Raman scattering spectrum measurements, and transmission electron microscope observations. The effect of Sm3+-doping on the microstructure, Raman scattering peak positions, and dielectric properties of composites comprising of fluorite-type SrBi2Nb2O9 nanocrystals and the Li2B4O7 glassy phase is clarified. It is found that fluorite-type SrBi2Nb2O9 nanocrystals transform to stable perovskite-type SrBi2Nb2O9 crystals with an orthorhombic structure by heat treatments at around 630 °C.

Proton magnetic resonance study of piezoelectric lithium formate monohydrate

Abstract is not available.

A proton magnetic resonance study of lithium acetate dihydrate, Li(CH3COO).2H20

Abstract is not available.

Lithium nuclear-magnetic-resonance in lithium acetate dihydrate, Li(CH3COO).2H2O

Li n.m.r, in single crystals of lithium acetate dihydrate is used to determine the quadrupole coupling parameters: (e2qQ/h) and r/. The orientations of the principal z, y and x components of the electric field gradient tensor are determined to be along the crystallographic b, a and c axes respectively. The parameters experimentally determined are (e2qQ/h)= 154"6 kHz; and i/= 0.9. This study indicates a tetrahedral configuration around the Li ion, confirming the recent X-ray and p.m.r, results.

Influence of Lithium Fluoride on the Burning Rate of AP-Polyester Propellant

THE addition of catalysts normally serves the purpose of imparting a desired burning rate change in a composite propellant. These may either retard or enhance the burning rate. Some often quoted catalysts are oxides, chromites and chromates of metals. A lot of work has been done on rinding the effect of the addition of some of these catalysts on the burning rate; however, none seems to have appeared on the influence of lithium fluoride (LiF). Only qualitative reduction in the burning rate of composite propellants with the addition of LiF was reported by Williams et al.1 Dickinson and Jackson2 reported a slight decrease in the specific impulse of composite propellant with the addition of LiF; however, they made no mention of the effect of its addition on the burning rate. We have studied the effect of the addition of varying amounts of LiF on the burning rate of Ammonium Perchlorate (AP)-Polyester propellant.

Ferroelectricity in lithium potassium sulphate

. Measurement of the relation between polarisation P and electric field E for lithium potassium sulphate (LiKSO4) was made in the low temperature range below room temperature. The P-E hysteresis loops along the c axis of LiKSO4 were observed in the low-temperature phase below the lower transition point Ttl of about -70 degrees C, and in the intermediate phase below the upper transition point Ttu of about -25 degrees C. These phases were found to be ferroelectric. The temperature dependence of the spontaneous polarisation Ps and the electric coercive field Ec were obtained.

Intermolecular potentials in the dimer, the excimers, and the dimer ions of ethylene

Calculations are reported on the interaction energies in the dimer, the excimers, and the dimer ions of ethylene. The various a- and u-electron terms for different conformations of the dimeric species are determined by using the exchange perturbation method. The results predict that the singlet excimer and the dimer cation are stable primarily because of the large magnitude of the exciton-resonance and charge-resonance terms, respectively, while the neutral dimer, the triplet excimer, and the dimer anion are weakly stable. The variations of the various energy terms with conformations suggest that these dimeric species cannot have identifical structure.

A study of interaction between two He+ ions in terms of the electronic forces

The potential energy curve of the He2+2 system dissociating into two He+ ions is examined in terms of the electronic force exerted on each nucleus as a function of the internuclear separation. The results are compared with the process of bond-formation in H2 from the separated atoms.

Korteweg-De Vries Equation for Non-Linear Ion-Acoustic Waves in a Plasma with Negative Ions

The theoretical analysis, based on the perturbation technique, of ion-acoustic waves in the vicinity of a Korteweg-de Vries (K-dV) equation derived in a plasma with some negative ions has been made. The investigation shows that the negative ions in plasma with isothermal electrons introduced a critical concentration at which the ion-acoustic wave plays an important role of wave-breaking and forming a precursor while the plasma with non-isothermal electrons has no such singular behaviour of the wave. These two distinct features of ion waves lead to an overall different approach of present study of ion-waves. A distinct feature of non-uniform transition from the nonisothermal case to isothermal case has been shown. Few particular plasma models have been chosen to show the characteristics behaviour of the ion-waves existing in different cases

High Lithium Storage in Mixed Crystallographic Phase Nanotubes of Titania and Carbon-Titania

Morphology and electrochemical performance of mixed crystallographic phase titania nanotubes for prospective application as anode in rechargeable lithium ion batteries are discussed. Hydrothermally grown nanotubes of titania (TiO2) and carbon-titania (C-TiO2) comprise a mixture of both anatase and TiO2 (B) crystallographic phases. The first cycle capacity (at Current rate = 10 mAg(-1)) for bare TiO2 nanotubes was 355 mAhg(-1) (approximately 1.06 Li), which is higher than both the theoretical capacity (335 mAhg(-1)) and the reported values for pure anatase and TiO2 (B) nanotubes. Higher capacity is attributed to it combination of the presence of mixed crystallographic phases of titania and trivial size effects. The surface area of bare TiO2 nanotubes was very high at 340 m(2) g(-1). C-TiO2 nanotubes showed a slightly lower first-cycle specific capacity of 307 mAhg(-1), but the irreversible capacity loss in the first cycle decreased by half compared to bare TiO2 nanotubes. The C-TiO2 nanotubes also showed a better rate capability, that is, higher capacities compared to bare TiO2 nanotubes in the Current range 0.1-2 Ag-1. Enhanced rate capability in the case of C-TiO2 is attributed to the efficient percolation of electrons as well its to the decrease in the anatase phase.

The role of lithium and magnesium perchlorate ammines in ammonium perchlorate decomposition

The preparation and thermal decomposition of lithium and magnesium perchlorate ammines have been investigated. The catalytic effect of these ammines on AP decomposition has been studied. The catalytic effect of lithium and magnesium salts on AP decomposition has been attributed to the formation of the metal perchlorate ammine intermediate. In the case of a magnesium salt: AP mixture, the melting of the magnesium perchlorate monoammine intermediate seems to play an important role in catalysing the decomposition.

Non-enzymatic reactions involving vitamin B6: Spectroscopic investigations on the effect of pH and metal ions on the decyclization reactions of the pyridoxal-histamine cyclized Schiff base

The effect of pH and metal ions (Cu2+, Zn2+, Cd2+, Mn2+, Cr3+, Co3+, and Mg2+) on the decyclization reactions of pyridoxal-histamine cyclized Schiff base has been studied using electronic spectroscopy. The study reveals that the cyclization reaction is irreversible with respect to pH and metal ions. Interest in this work derives from the possible involvement of cyclization reactions in the inhibitory activity of a number of pyridoxal-dependent enzymes.

Soft matter lithium salt electrolytes: ion conduction and application to rechargeable batteries

Soft matter provides diverse opportunities for the development of electrolytes for all solid state lithium batteries. Here we review soft matter solid electrolytes for lithium batteriesthat are primarily obtained starting from liquid electrolytic systems. This concept of solid electrolyte synthesis from liquid is significantly different from prevalent approaches. The novelty of our approach is discussed in the light of various fundamental issues and in relation to its application to rechargeable lithium batteries.

Carbon-coated hierarchical SnO2 hollow spheres for lithium ion batteries

Hierarchical SnO2 hollow spheres self-assembled from nanosheets were prepared with and without carbon coating. The combination of nanosized architecture, hollow structure, and a conductive carbon layer endows the SnO2-based anode with improved specific capacity and cycling stability, making it more promising for use in lithium ion batteries.

Atomic layer-by-layer Co3O4/graphene composite for high performance lithium-ion batteries

An "atomic layer-by-layer" structure of Co3O4/graphene is developed as an anode material for lithium-ion batteries. Due to the atomic thickness of both the Co3O4 nanosheets and the graphene, the composite exhibits an ultrahigh specific capacity of 1134.4 mAh g-1 and an ultralong life up to 2000 cycles at 2.25 C, far beyond the performances of previously reported Co3O4/C composites.