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The relationship between phases and the electrical properties of bismuth perovskite ([Bi.sub.1/2][Na.sub.1/2])Ti[O.sub.3] (BNT)- and ([Bi.sub.1/2][K.sub.1/2])Ti[O.sub.3] (BKT)-based lead-free ferroelectric ceramics is studied. BKT ceramics are prepared by the hot-pressing (HP) method and BKT ceramics doped with a small amount of Bi have shown a relatively high remanent polarization and high piezoelectric properties.

A combination of scanning and titration calorimetry is used to investigate the effect of the anionic surfactant sodium dodecylsulfate (SDS) on the equilibrium, kinetic and thermal stability of the cutinase from Humicola insolens (HiC). The analysis reveals that the equilibrium stability of HiC is strongly decreased by SDS, as it is highly dependent on the electrostatic repulsion of the increasingly negatively charged HiC-SDS complexes.

Quaternary complex hydride compounds within the bialkali Na-Li-Al-H hydrogen storage system were investigated by first-principles modeling, experimental and thermodynamic methodologies. The results led to propose transformation pathways between distorted [Na.sub.2]LiAl[H.sub.6] allotrope and the less stable cubic allotrope observed at room temperature.

A general synthesis of high-quality alpha- and beta-phase NaRE[F.sub.4] and NaY[F.sub.4]:Yb,Er/Tm nanocrystals are demonstrated through the co-thermolysis of Na(C[F.sub.3]COO) and Re[(C[F.sub.3]COO).sub.3]. By tuning the ratio of Na/RE, solvent composition, reaction temperature and time, the phase, shape and size of the NaRE[F.sub.4] nanocrystals can be manipulated.

We have studied experimentally the effects of variable [Na.sub.2]0 concentrations on the solubility of four metals (Fe, Co, Ni, and Pd) in silicate melts of anorthite-diopside eutectic composition. Experiments were done at fixed temperatures of 1300 [degrees]C for Pd and 1400 [degrees]C for Ni, Co, and Fe. In the Fe solubility experiments, Na losses were severe. Therefore, a new experimental device (crucible-supported loop technique or CSLT) was designed to prevent Na losses of experimental charges primarily for experiments at low oxygen fugacities. The CSLT was tested extensively, and it was demonstrated that high Na partial pressures could be kept in a semi-closed crucible for at least 20 h. In experiments on Co solubilities, the CSLT was tested with reversed experiments. The Fe and Co solubilities clearly decrease with increasing [Na.sub.2]O contents. The Ni solubility is independent of [Na.sub.2]O contents up to 4.5 wt%. At oxidizing conditions, a small decrease in Ni solubility with increasing Na content was found. Palladium shows a mixed behavior, decreasing solubility with increasing [Na.sub.2]O, up to about 4 wt%. At higher Na contents, Pd solubility is independent of Na content. The increase of FeO activity coefficients with increasing Na content found in this study may provide an explanation for decreasing FeO with decreasing degrees of partial melting in experimentally produced mantle melts (Hirschmann et al. 1998), as melts at low melting degrees are Na-rich. Keywords: Melt properties, new technique, thermodynamics, experimental petrology

A high-temperature molecular dynamics has been employed to investigate self-transport and cooperative transport of benzene in NaX. The benzene-NaX force field has been refined for use with framework force field for aluminosilicates.

Synthesis of NaFe4P12 nanosprings was done using a hydrothermal method at 170 degree C for 24h. The length of the nanosprings was 1000-5000 nm and they were 200-1000 nm in diameter and consisted of coiled nanobelts of 80-150 nm in width and 20-50 nm in thickness.

Absorption and fluorescence spectra of Er(super 3+) (4f(super 11)) in crystals of NaBi(WO4)2 (NBW) is reported at temperatures between 15 K and room temperature. The quasi-center models has merit when used to calculate the crystal-filed splitting of the energy levels of the trivalent rare-earth ions in crystal hosts having a disordered structure.

The hydrothermal crystallization of sodium zeolite A from amorphous aluminosilsicate gels at 80-120 degree Celsius is investigated via a time-resolved in situ energy-dispersive X-ray diffraction. The course of crystallization reaction is analyzed by quantifying the Avarami-Erofe'ev nucleation growth curves, which indicate that choice of silica starting material affect the course of reaction, and the concentration of NaOH and temperature determine the crystallization behavior.

Phase transitions of sodium niobate, prepared by solid state synthesis method, are examined by using dielectric measurements in order to contribute to the clarification of its structural behavior below 400 [degree]C. The results have shown the existence of the Q polymorph at room temperature, which has undergone a transition to the R polymorph upon heating through a temperature region between 265 and 326.5 [degree]C.

Gelcasting technology is used for preparing 0.94[Bi.sub.0.5][Na.sub.0.5]Ti{O.sub.3]-0.06BaTi[O.sub.3] (BNBT6) lead-free piezoelectric ceramics and their dielectric and piezoelectric properties are examined. The specimens are sintered at 1100-1200 [degree]C after grain-oriented under the pulsed strong magnetic field during the solidification of the green bodies and it is observed that the orientation degree has increased with increasing sintering temperature.

The article presents a complete analysis of the preparation and the electrical properties of the various (1- x)[Bi.sub.0.5][Na.sub.0.5]Ti[O.sub.3]- xBi([Zn.sub.0.5][Ti.sub.0.5])[O.sub.3] lead-free piezoceramics. The Curie temperature of the compounds is shown to be shown to highly increase with the BZT composition.

Several studies are conducted to explain the synthesis and characterization of the alkali metal doped [Na.sub.0.75]Co[O.sub.2] thermoelectric oxide. The phase formation and magnetotransport properties of the system are also determined.

A newly discovered physical phenomenon in a variety of piezoelectric (K,Na)Nb[O.sub.3]-based ceramics is reported. Strong piezoelectric temperature stabilities exhibited by the orthorhombic phase compared to tetragonal phase could be applied for the future compositional designs of (K,Na)Nb[O.sub.3]-based lead-free piezoelectric ceramics.

A combination of infrared reflectance and Raman spectroscopy techniques is employed to explain the polarization mechanisms, as well as the structural rearrangements that are observed in the thermally poled sodium-alumino phosphate glasses.

Perovskite-based solid solution of x[Na.sub.1/2][Bi.sub.1/2]Ti[O.sub.3]-(1-x)BaTi[O.sub.3] (x

Lead-free ([K.sub.0.50][Na.sub.0.50])Nb[O.sub.3] (KNN) thin films with a higher degree of (100) preferred orientation are deposited on the SrRu[O.sub.3]-buffered SrTi[O.sub.3] (100) substrate by off-axis radio frequency magnetron sputtering. They have shown lower phase transition temperatures, enhanced ferroelectric behavior, fatigue endurance along with a lower dielectric loss and a lower leakage current when compared to the bulk ceramic counterpart.

A study was conducted to examine the first-principles calculations of the electronic, optical, and lattice dynamic properties of LiIn[Se.sub.2] polymorph using density functional theory plane-wave pseudopotential method. Findings revealed that [alpha]-NaFe[O.sub.2]-type LiIn[Se.sub.2] does not have only optical properties but also has vibrational properties and thermodynamic properties.

Two homologous and isostructural compounds [Na.sub.5][M.sub.2+x][Sn.sub.10-x] (M = Zn, Hg) are obtained by direct reaction of the elements at high temperature and the crystal structures of these phases are determined from single-crystal X-ray diffraction data. Rigid band analyses have shown that the electronic structure of the phases with the compositions have corresponded to heavily doped semiconductors, thus meeting an important requirement of thermoelectric materials.

The spray technique at different substrate temperatures were utilized to deposit the composite films of sodium nitrite (NaN[O.sub.2]) and poly(vinyl alcohol) (PVA). The back switching calculations and the switching characteristics indicated that 180 degree domains contribute more towards the composite than the pure NaN[O.sub.2] film.

The effect of substitution of Cu, Zn, Ga, Mn and Ni for Co in layered [Na.sub.x]Co[O.sub.2] on its resistivity ([rho]), magnetization (M), and thermopower (S) is examined. The studies have shown that irrespective of the charge and spin states of the impurity ion, thermopower has increased smoothly with doping concentration and unlike resistivity, and thermopower of the Cu-doped samples has not shown any anomalous behavior.

Several studies are conducted to explain the laser performance and the detailed polarized spectral properties of the [Tm.sup.3+]-doped NaLa[(Mo[O.sub.4]).sub.2] crystal. The experiment has proved to be helpful in obtaining the room-temperature quasi-cw laser of the crystal.

The ferroelectric properties of sodium nitrite (NaN[O.sub.2]):poly(vinyl alcohol) nanocomposite films, which are prepared by the solvent cast method, are analyzed. These films have displayed improved remanent polarization and stability, which is attributed to the reduced strain in the composite films.

Preparations of glass ceramic composites by bulk crystallization of NaNbO3 in sodium niobium borate glasses are presented. A homogeneous bulk crystallization of the NaNbO3 phase is found to take place during heat treatments that produces visible-near infrared transparent materials with ~30 nm NaNbO3 nanocrystallites.

A method is described for thermal poling of sodium borophosphate niobium glass films deposited on silicon wafers and the effect of the external applied voltage on the poles films quality is examined. The second harmonic signals generated by thermal poling are analyzed in reflection mode and the thermally poled niobium sodium borophosphate thin films are revealed of real interest as potential electro-optic devices.

Persistent spectral hole burning is observed in europium-doped sodium germanate glass. It is found that hole-burning efficiency increases by 85% when the glasses are made in a reduced atmosphere, and hole burning is detected even at room temperature.

Magnetic field dependent thermoelectric power (TEP) of the Na-doped La(sub 0.7)Ca(sub 0.3-y)Na(sub y)MnO(sub 3) (0.0 less than or equal to y less than or equal to 0.3) system has been studied in the temperature range 80-300 K. This system supports small polaron hopping (SPH) conduction mechanism above the respective MIT temperature.

Two mesostructured MCM-41 silicas that differ widely in hydrothermal stability are examined by 29Si MAS NMR spectroscopy and pair distribution function (PDF) analysis of synchrotron x-ray scattering data. The sodium-free mesostructure assembled from fumed silica derivative, however is greatly compromised when doped with as little as 0.10%Na2O, thus confirming the deleterious effect of sodium on hydrothermal stability.