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101.
Kenta Nagamine Keita Hirose Tsuyoshi Honma Takayuki Komatsu 《Solid State Ionics》2008,179(13-14):508-515
The glasses with the composition of 37.5Li2O–(25 − x)Fe2O3–xNb2O5–37.5P2O5 (mol%) (x = 5,10,15) are prepared, and it is found that the addition of Nb2O5 is effective for the glass formation in the lithium iron phosphate system. The glass–ceramics consisting of Nasicon-type Li3Fe2(PO4)3 crystals with an orthorhombic structure are developed through conventional crystallization in an electric furnace, showing electrical conductivities of 3 × 10− 6 Scm− 1 at room temperature and the activation energies of 0.48 eV (x = 5) and 0.51 eV (x = 10) for Li+ ion conduction in the temperature range of 30–200 °C. A continuous wave Nd:YAG laser (wavelength: 1064 nm) with powers of 0.14–0.30 W and a scanning speed of 10 μm/s is irradiated onto the surface of the glasses, and the formation of Li3Fe2(PO4)3 crystals is confirmed from XRD analyses and micro-Raman scattering spectra. The crystallization of the precursor glasses is considered as new route for the fabrication of Li3Fe2(PO4)3 crystals being candidates for use as electrolyte materials in lithium ion secondary batteries. 相似文献
102.
103.
Glass formation in Li2O-Nb2O5-GeO2 (LNG) system, the structure and crystallization behavior of glasses that have compositions near the ratio Li2O/Nb2O5 ∼ 1 corresponding to stoichiometry of ferroelectric phase LiNbO3 were examined by differential thermal analysis, X-ray diffraction, small-angle neutron scattering and second harmonic generation (SHG). LNG glasses were subjected to heat treatments at temperatures in the range between Tg and temperature of the first exothermic peak in order to initiate nonlinear optical activity by nanoheterogeneity formation. Transparent nanostructured glasses with second-order optical nonlinearity were obtained for compositions characterized by the Li2O/Nb2O5 molar ratio ranging from 0.83 to 1.2 and GeO2 40-45 mol%. As prolonged heat treatments of nanostructured glasses result in crystallization of ferroelectric LiNbO3 the origin of SHG in transparent LNG glasses is supposed to be connected predominantly with polarity of nanoheterogeneities formed at the initial stage of phase separation. 相似文献
104.
V.N. Sigaev N.V. Golubev S.Yu. Stefanovich T. Komatsu Y. Benino P. Pernice A. Aronne E. Fanelli B. Champagnon V. Califano D. Vouagner T.E. Konstantinova V.A. Glazunova 《Journal of Non》2008,354(10-11):873-881
Amorphous nanoheterogeneities of the size less than 100 Å have been formed in glasses of the Li2O–Nb2O5–SiO2 (LNS) and Li2O–ZnO–Nb2O5–SiO2 (LZNS) systems at the initial stage of phase separation and examined by transmission electron microscopy, small-angle X-ray and neutron scattering. Both LNS and LZNS nanoheterogeneous glasses exhibit second harmonic generation (SHG) even when they are characterized by fully amorphous X-ray diffraction (XRD) patterns. Chemical differentiation and ordering of glass structure during heat treatments at appropriate temperatures higher Tg lead to drastic increase of SHG efficiency of LNS glasses contrary to LZNS ones in the frame of amorphous state of samples. Following heat treatments of nanostructured glasses result in crystallization of ferroelectric LiNbO3 and non-polar LiZnNbO4 in the LNS and LZNS glasses, respectively. Taking into account similar polarizability of atoms in LNS and LZNS glasses, the origin of the principal difference in the second-order optical non-linearity of amorphous LNS and LZNS samples is proposed to connect predominantly with the internal structure of formed nanoheterogeneities and with their polarity. Most probably, amorphous nanoheterogeneities in glasses may be characterized with crystal-like structure of polar (LiNbO3) phase initiating remarkable SHG efficiency or non-polar (LiZnNbO4) phase, which do not initiate SHG activity. It gives an opportunity to vary SHG efficiency of glasses in a wide rage without remarkable change of their transparency by chemical differentiation process at the initial stage of phase separation when growth of nanoheterogeneities is ‘frozen’. At higher temperatures, LiNbO3 crystals identified by XRD precipitate in LNS glasses initiating even more increase of SHG efficiency but visually observable transparency is impaired. 相似文献
105.
Kazuki Komatsu Stefan Klotz Satoshi Nakano Shinichi Machida Takanori Hattori Asami Sano-Furukawa 《高压研究》2020,40(1):184-193
ABSTRACTA new high pressure cell for neutron diffraction experiments using nano-polycrystalline anvils is presented. The cell design, off-line pressure generation tests and a gas-loading procedure for this cell are described. The performance is illustrated by powder neutron diffraction patterns of ice VII to ~82?GPa. We also demonstrate the feasibility of single crystal neutron diffraction experiments of Fe3O4 at ambient conditions using this cell and discuss the current limitation and future developments. 相似文献
106.
107.
Syuuhei Komatsu Hidenari Kayano Yu Ando Taka-Aki Asoh Ryo Ishihara Akihiko Kikuchi 《Journal of polymer science. Part A, Polymer chemistry》2018,56(23):2623-2629
We herein report the preparation of thermo- and redox-responsive branched polymers by the condensation reaction of three-armed oligo(ethylene glycol) (trisOEG) and cystamine (CA). The prepared branched polymers exhibited a soluble–insoluble transition at a lower critical solution temperature (LCST) and formed coacervate droplets through a liquid–liquid phase separation process. We then demonstrated control of the LCSTs of the branched polymers by varying the feed ratio of CA and the surrounding salt concentration close to body temperature. In addition, the trisOEG-cys x polymer formed coacervate droplets above the LCST, in which hydrophobic molecules were condensed. The redox response of the branched polymers was also investigated. Interestingly, the branched polymers degraded to low-molecular-weight materials (i.e., trisOEG) in the presence of dithiothereitol as a reducing agent through cleavage of the disulfide bond of CA. This facile preparation of branched polymers is expected to be valuable in the context of functional biomedical materials and modifiers for materials surfaces, such as the bases for drug delivery carriers and separation materials. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2623–2629 相似文献
108.
A novel mediator-polymer-modified anode for microbial fuel cells 总被引:1,自引:0,他引:1
Adachi M Shimomura T Komatsu M Yakuwa H Miya A 《Chemical communications (Cambridge, England)》2008,(17):2055-2057
A high-performance anode system based on a combination of mediator-polymer-modified graphite felt and bacteria capable of reducing extracellular materials shows significant potential for practical use in microbial fuel cells (MFCs). 相似文献
109.
Stereoselective synthesis of benzyl-protected β-galactosides by propionitrile-mediated glycosylation
Akiharu Ueki Masafumi Hirota Keiko Komatsu Yutaka Takano Michio Iwaoka Hironobu Hojo Yoshiaki Nakahara 《Tetrahedron》2008,64(11):2611-2618
β-Selective galactosylation was studied using a series of 2-O-benzylated phenyl 1-thio-galactosides and glycosyl acceptors in propionitrile with BSP-TTBP-Tf2O. The glycosylation enabled us to synthesize useful precursors of N-acetyllactosamine and core 1 O-glycoserine derivatives in a highly convergent manner. 相似文献
110.
Transparent crystallized glasses consisting of nonlinear optical Ba(2)TiSi(2)O(8) nanocrystals are prepared in Eu(2)O(3)-, Nd(2)O(3)-, and Er(2)O(3)-doped 40BaO-20TiO(2)-40SiO(2) glasses by a conventional heat treatment method in order to clarify the optical properties of rare-earth (RE) ions in nanocrystals. The electronic polarizabilities of crystallized glasses are evaluated from the values of density and refractive index, and are found to decrease due to nanocrystallization, which indicates that the chemical bonding state in the crystallized glasses is more covalent compared to the precursor glasses. It is proposed from x-ray diffraction analyses and photoluminescence spectra of Eu(3+) ions that RE ions such as Nd(3+) and Eu(3+) are incorporated into Ba(2)TiSi(2)O(8) nanocrystals. The Judd-Ofelt parameters, Omega(t) (t=2, 4, and 6), of Nd(3+) and Er(3+) ions are evaluated from optical absorption spectra. It is observed that the Omega(2) parameter of Nd(3+) and Er(3+) increases largely due to nanocrystallization, suggesting that the site symmetry of Nd(3+) and Er(3+) ions in nanocrystallized glasses is largely distorted due to their incorporations into the Ba(2+) sites in Ba(2)TiSi(2)O(8) nanocrystals. The change in the Omega(4) and Omega(6) parameters due to nanocrystallization is small. It is proposed that nonlinear optical Ba(2)TiSi(2)O(8) nanocrystals including RE ions would have a high potential as active optical materials. 相似文献