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11.
Yu Ogawa Hitomi Hidaka Satoshi Kimura Ung-Jin Kim Shigenori Kuga Masahisa Wada 《Cellulose (London, England)》2014,21(2):999-1006
We investigated the crystal structure of alkali-celluloses, Na-cellulose IIA and II(Cu), formerly known as Na-cellulose IIB, by synchrotron X-ray diffraction. Na-cellulose IIA, formed from cellulose I by high-concentration NaOH treatment, has a fiber repeat of 15 Å and a threefold-like helical conformation. Na-cellulose II(Cu), prepared by treating cellulose I with copper-saturated alkali solution, also has a fiber repeat of 15 Å with threefold helical symmetry. Incorporation of Cu(II) ions into cellulose was confirmed by multiwavelength anomalous diffraction. Monitoring by X-ray diffraction revealed that the formation of this complex from cellulose I is remarkably slow, probably because of the involvement of copper ion. The stability of alkali-cellulose II(Cu) was tested to estimate the influence of the presence of copper in the crystal. Na-cellulose II(Cu) characteristically dissolved in aqueous ammonia solution, indicating strong coordination of copper ion to cellulose. 相似文献
12.
Shiho Tokonami Keisuke Nishida Yushi Nishimura Shimpei Hidaka Yojiro Yamamoto Hidenobu Nakao Takuya Iida 《Research on Chemical Intermediates》2014,40(6):2337-2346
We investigated the optical response of a huge number of silver nanoparticles (AgNPs) densely assembled on an organic microsphere, i.e., AgNP-fixed bead, under the collective phenomena of localized surface plasmons. For this purpose, various optical properties of such a AgNP-fixed bead were analyzed in aqueous solution by dark-field optical microscopy and laser Raman microscopy. In particular, in comparison with the optical spectrum of single AgNPs, significant spectral broadening and redshift were observed due to plasmonic superradiance with decreasing interparticle distance to the subnanoscale when using small binder molecules in the AgNP-fixed bead. Furthermore, we observed surface-enhanced Raman scattering and clarified the sensitivity of the signal intensity to the size of the binder molecules between the AgNPs, which can be explained based on optical response theory using a discrete integral with spherical cells. These results and discussion provide a guiding principle for broadband plasmonic light absorbers and for highly sensitive detection of small molecules and nanoscale biomaterials based on vast numbers of nanogaps produced by a bottom-up self-assembly process. 相似文献
13.
When certain trivalent rare-earth ions (Ln's) are co-doped in CaGa2S4:Mn2+ as sensitizers, the Mn red emission of the compound is strikingly enhanced. In this work, efficiency of each lanthanide is studied. The best efficiencies are achieved with La3+-, Pr3+-, and Tb3+- co-doped compounds, for each of which the effects of concentrations of the co-doped ions on the Mn2+ emission are investigated. The energy-transfer mechanisms and the location of electronic energy levels of both the trivalent and the divalent lanthanides in the energy band gap of the host material are discussed. Depending on Ln's, charge transfer or cross-relaxation should be taken into account. 相似文献
14.
Yoshiyuki Shirakawa Yusuke Hayashi Kazunori Kadota Hiroshi Mio Hiroto Ohtsuki Atsuko Shimosaka Jusuke Hidaka 《Journal of nanoparticle research》2008,10(4):577-584
In our previous paper, structural changes of selenium powders ground by a planetary ball mill at various rotational speeds
were investigated for the nanostructural modification of particles using mechanical grinding process. The experimental results
indicated that the amorphisation of Se by grinding accompanies lattice strain, and the lattice strain arises from impact energy
which is more than an energy related to intermolecular interaction. In this paper, molecular dynamics simulations of selenium
have been carried out under compressing conditions of various pressure strengths for obtaining information of the lattice
strain at atomic level. Then, dynamical behaviour of atomic configuration has been discussed in this process. The structural
disordering and formation of the structural defects were estimated by deviations of bond length and angle and the number of
created defects before and after compressing from simulated results. The disordering took place during compressing at various
pressure strengths, and the disordered atoms return to their initial positions at lower pressure. Stable disordered state
and defects after the compression can however remain by compression at more than a certain pressure strength mainly associated
with binding energy of selenium. 相似文献
15.
Fukami T Mugishima A Suzuki T Hidaka S Endo T Ueda H Tomono K 《Chemical & pharmaceutical bulletin》2004,52(8):961-964
Improvement of solubility for fullerene (C60) was studied by cogrinding with cycloamyloses using a ball mill in the solid state. Cycloamylose is a novel cyclic alpha-1,4-glucan produced from synthetic amylose by enzymatic reaction. Although sample solutions showed a pale yellow for the initial period of cogrinding with cycloamyloses and C60, the color varied to brown after 48 h. Subsequently, the solubility of C60 was improved markedly to 560 (microg/ml) at 96 h. From powder X-ray diffraction analysis, the peak intensity of crystalline C60 decreased as the cogrinding time was extended. The UV-VIS absorption spectrum of C60 shows absorption bands at 262 and 340 nm in water with cycloamyloses, and 258 and 328 nm in n-hexane. These results suggested that C60 molecules were dispersed into cycloamyloses micellar system and the red-shift of the UV-VIS spectra was due to an intermolecular interaction between C60 and cycloamyloses. 相似文献
16.
Hidemasa Hidaka Masao Hirayama Kazuhiko Yamada 《Journal of carbohydrate chemistry》2013,32(4):509-522
I. INTRODUCTION Recently the study of oligosaccharides has been extensively pursued in Japan after the findings of the remarkable biofunctions and usefulness of fructooligosac-charides for human health, improving the intestinal microflora and importance in livestock nutrition. 相似文献
17.
18.
S. Onari T. Hiroaki A. Ono S. Hidaka T. Arai T. Mori 《International Journal of Infrared and Millimeter Waves》1989,10(7):737-744
Systematic measurements of the far infrared reflection spectra of high Tc superconductors LnBa2Cu3Ox for various Ln as shown in the title were performed. Infrared reflection spectra of tetragonal LnBa2Cu3Ox exhibit Reststrahlen vibration near 640, 590, 530, 355 and 250 cm–1, common to these materials, and the spectra of the orthorhombic LnBa2Cu3Ox exhibit the characteristics of free carriers except PrBa2Cu3Ox with weak phonon structures near 617, 570, 317 and 285 cm–1. PrBa2Cu3Ox is not a superconductor, and it has no characteristic broad band due to free carriers for all x in the range of 6 to 7. Lattice dynamical calculation was performed by the use of the shell model and the calculated results express quite well the characteristic features of infrared experiments. 相似文献
19.
Y. Tsuchiya Y. Nakajima T. Tamegai S. Nagasawa M. Hidaka 《Physica C: Superconductivity and its Applications》2011,471(21-22):808-811
We have observed flux penetrations into square superconducting networks of Nb with various thicknesses and hole-shapes by using magneto-optical imaging method. The penetrated pattern does not depend on the thickness and extends along diagonal direction when the samples have smaller area in the intersection of networks. We have also observed similar superconducting networks with and without small holes at the intersection. The small holes at the intersection do not work as a promoter for the diagonal flux penetration though the parallel flux penetration becomes weak. We discuss possible origins of these anomalous anisotropic flux penetrations. 相似文献
20.