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We analyzed the Fe 3d electronic structure in LiFePO4 /FePO4 (LFP/FP) nanowire with a high cyclability by using soft X-ray emission spectroscopy (XES) combined with configuration-interaction full-multiplet (CIFM) calculation. The ex situ Fe L2,3 -edge resonant XES (RXES) spectra for LFP and FP are ascribed to oxidation states of Fe2+ and Fe3+ , respectively. CIFM calculations for Fe2+ and Fe3+ states reproduced the Fe L3 RXES spectra for LFP and FP, respectively. In the calculations for both states, the charge-transfer energy was considerably larger than those for typical iron oxides, indicating very little electron transfer from the O 2p to Fe 3d orbitals and a weak hybridization on the Fe-O bond during the charge-discharge reactions.

A key challenge in processing carbon nanotubes and their composites for large-scale applications is aggregation. Cation-π stacking interactions have been discovered to disperse heavily entangled single-walled carbon nanotube (SWNT) bundles in ionic liquids (ILs). In this work, we found that a dispersible, silky single-layer graphene (SLG) can be readily gathered together to form a crosslinked gel after entrapping sufficient IL molecular via the likely noncovalent interaction. By incorporating the dispersed SWNTs into the gathered SLG gel synchronously, we prepared solid, finely crosslinked SWNTs-SLG films, assisted by an avenue of 2-step extraction to remove the IL completely. The gel-derived SWNTs-SLG complex film was applied as a support material of oxygen cathodes for Li-O2 batteries. It exhibited a remarkable improved cycleability in comparison to made of SWNTs and SLG alone due to the finely crosslinked feature. Decorated SWNTs and SLG can also form gel-derived complexes via the same process to construct support-catalyst complexes. A SWNTs-SLG film loaded with Ru nanoparticles exhibited not only catalytic effects, but also the ability to suppress the side reactions, and hence stabilized the whole Li-O2 battery. Our research introduces a gel-derived, high-dispersed processing of carbon nanotube-graphene complexes and demonstrates their favorable applications on Li-O2 batteries.

Thin, semiconducting BaTiO 3 ceramic wires prepared in the present study exhibited reversible stress-induced, nonlinear current-voltage characteristics across several grain boundaries. A remarkable change in resistance with the application (by the three-point bending method) of only ∼1% tensile deformation indicated that the BaTiO 3 wires may have potential as stress-sensing devices. Resistance in the BaTiO 3 wires both increased and decreased with increasing tensile stress parallel to the electric fields, far below the ferroelectric transition temperature, T c ; in Sr-substituted wires near T c , on the other hand, resistance only increased. Detailed studies of the patterns and fluctuation of polarization at grain boundaries could be meaningful, because stress-sensing characteristics may be induced by changes in the relative angle between polarization vectors of adjacent grains.

Definite increases in the Curie point (TC) of undoped and lanthanum- (La-) doped (

Pure, translucent, and highly crystallized barium titanate (BaTiO3) monolithic gels were synthesized via a sol-gel technique at temperatures down to 90°C by using a high-concentration solution of barium alkoxide and titanium alkoxide. The gels consisted of fine particles with an average diameter of ~10 nm and showed the X-ray diffraction patterns of a pseudo-cubic BaTiO3 system at room temperature; however, in bulk crystal, the tetragonal structure was more stable. The optical transmission spectra of the polycrystalline gels were similar to those for single-crystalline BaTiO3. From the excitation energy dependence of the absorption-edge structures, the optical-gap energies for the gels were estimated to have values that were ~0.1 eV higher than those for the single crystal; these higher optical-gap energies may be attributed to size effects.

Exons 1-3 of the p16/CDKN2 gene, exons 4-9 of the p53 gene and exons 1 and 2 of H-, K- and N-ras genes were screened for mutations by a combination of immunohistochemistry and single-strand conformational polymorphism (SSCP) analyses of polymerase chain reaction products from human surgical samples of both frank oral squamous cell carcinomas and premalignant lesions. The samples included 20 squamous cell carcinomas, 10 epithelial dysplasias and 10 epithelial hyperplasias. No identifiable gene mutations were detected in any of the dysplasias or hyperplasias, while 2 (10%) deletions and 2 (10%) mutations of p16/CDKN2, along with 5 (25%) p53 mutations were found in the advanced carcinomas, yielding characteristic p16/ CDKN2 and p53 changes. A mutation in the K-ras gene was found in single carcinoma and dysplastic samples. From the data, it can be argued that p16/CDKN2 and p53 mutations are relatively late occurrences in human oral tumorigenesis and that genetic alterations of the ras genes may not play a significant role in squamous neoplasia.

To elucidate the role of the p53 tumor suppressor gene in prostate tumorigenesis, we probed for mutations in latent and clinical prostate cancers using single strand conformation polymorphism (SSCP) and restriction fragment length polymorphism (RFLP) analysis in combination with direct gene sequencing and immunohistochemical methodologies. Fifteen cases of subclinical and 32 cases of clinical carcinoma, the latter graded in stages A through D, were available for study. While p53 point mutations were detected in only 5 of 32 (16%) clinical cancers, no mutations were detected in latent disease. Of the carcinomas in stages B, C and D, 15% (2/13), 29% (2/7) and 9% (1/11) were positive for p53 mutations, respectively. Although no specific mutational patterns were observed, the aberrations found were predominantly single base missense substitutions. The data suggest not only an association of p53 mutation and progression of clinical prostate cancer, but also imply that some other mechanism(s) are at work in latent carcinoma.

Thin, semiconducting barium titanate (BaTiO 3 ) ceramic bars, with a diameter of 10 to 20 μm, consisting of single grains joined together in series have been prepared to investigate the piezoresistivity in the materials, which was evaluated from their current (I)-voltage (V) characteristics under the loading condition of various bending stresses. I-V characteristics of single grain boundaries in some of the materials were found to exhibit distinct differential negative resistance (DNR) at room temperature with its feature changing with stress. The DNR appeared on the I-V curves at an electric field of several volts per one grain, and has been confirmed to be connected with the transition of current between two conduction states in the grain boundary region. The obtained results indicate that this phenomenon cannot be interpreted by a rise in the temperature of the materials up to their positive temperature coefficient of resistivity (PTCR) region above the Curie point by Joule heating due to current flow, that is their self-heating effect. This newly observed DNR phenomenon has thus been tentatively interpreted by the morphological change in the ferroelectric domain structure in the vicinity of grain boundaries under mechanical and electric stresses, on an assumption that different configurations of ferroelectric domains yield different conduction states in the grain boundary due to a difference in the degree of surface acceptor charge compensation or the anisotropic carrier mobilities in the crystal.

Pure, translucent, and highly crystallized barium titanate (BaTiO3) monolithic gels were synthesized via a sol-gel technique at temperatures down to 90°C by using a high-concentration solution of barium alkoxide and titanium alkoxide. The gels consisted of fine particles with an average diameter of ~10 nm and showed the X-ray diffraction patterns of a pseudo-cubic BaTiO3 system at room temperature; however, in bulk crystal, the tetragonal structure was more stable. The optical transmission spectra of the polycrystalline gels were similar to those for single-crystalline BaTiO3. From the excitation energy dependence of the absorption-edge structures, the optical-gap energies for the gels were estimated to have values that were ~0.1 eV higher than those for the single crystal; these higher optical-gap energies may be attributed to size effects.