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231.
We have discriminated individual Ge atoms from the intermixed Ge/Si(1 1 1)-(7 × 7) surface using a non-contact atomic force microscope at a room temperature environment. In fact, Si-Ge (IV-IV) binary system is considered as one of the most difficult systems for atomic discrimination among atoms in the IV group because of the similarities in the electronic and chemical properties. However, in this study, we found one of the most attractive tools to discriminate a specific atom from the others even in the difficult Si-Ge system. Ge atoms are shown as dim spots in comparison to Si atoms with bright spots on the intermixed surface by a weak chemical bonding energy and/or a relaxation effect despite large atomic radius and high spatial position in both variable frequency shift and topographic images. The discrimination of individual atoms with respect to the chemical interaction variation will further provide a chance to manipulate different atomic species and assemble various nanostructures in near future. 相似文献
232.
Norihiro Tsujioka Seiichi Imakura Naoya Nishi Takashi Kakiuchi 《Analytical sciences》2006,22(5):667-671
Ion transfer across the polarized interface between a room-temperature ionic liquid (RTIL) or room-temperature molten salt, tetrahexylammonium bis(trifluoromethylsulfonyl)imide (THAC(1)C(1)N), and water has been studied voltammetrically using a micro liquid-liquid interface formed at the orifice of a glass capillary micropipette. A small current of nanoampere level circumvents the problem of the iR drop in the viscous ionic liquid phase. Voltammograms for the transfer of moderately hydrophilic ions, such as BF(4)(-) and ClO(4)(-), from the aqueous phase in the capillary to the bulk of THAC(1)C(1)N in which the capillary is submerged, show steady-state characteristics in that the current does not depend on the scan rate up to a few hundred millivolt per second, and the plateau in the limiting current region is proportional to the bulk concentration of analyte ions. Owing to the steady-state current, which is presumably ascribed to a noncylindrical geometry of the capillary tip, the relative magnitude of the hydrophobicity, or the affnity to the RTIL, of a series of ions can be determined from the half-wave potentials of voltammograms. 相似文献
233.
Puneet Pathak Nishi Kant Bhardwaj Ajay Kumar Singh 《Applied biochemistry and biotechnology》2014,172(8):3776-3797
This paper implies production of cellulase and xylanase enzyme using a potent strain of Trichoderma harzianum for the efficient deinking of photocopier waste papers. Different nutritional and environmental factors were optimized for higher production of cellulase along with xylanase. After fermentation, maximum enzyme extraction was achieved from fermented matter using a three-step extraction process with increased efficiency by 26.6–29.3 % over single-step extraction. Static solid state was found as the best fermentation type using wheat bran (WB) as carbon source and ammonium ferrous sulfate (0.02 M) as nitrogen source. Subsequently, inoculum size (8?×?106 CFU/gds), incubation days (4 days), temperature (34 °C), initial pH (6.0), and moisture ratio (1:3) significantly affected the enzyme production. Cellulase and xylanase activities were found to be maximum at pH 5.5 and temperature 55–60 °C with good stability (even up to 6 h). Furthermore, this crude enzyme was evaluated for the deinking of photocopier waste papers without affecting the strength properties with improved drainage as an additional advantage. The crude enzyme-deinked pulp showed 23.6 % higher deinking efficiency and 3.2 % higher brightness than chemically deinked pulp. Strength properties like tensile, burst indices, and folding endurance were also observed to improve by 6.7, 13.4, and 10.3 %, respectively, for enzyme-deinked pulp. However, the tear index was decreased by 10.5 %. The freeness of the pulp was also increased by 21.6 % with reduced drainage time by 13.9 %. 相似文献
234.
Shin-Ichi Nishi Minoru Matsuda 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-2):181-185
Abstract The free ion of fluorenone radical anion (FlO) was formed even in tetrahydrofuran (THF) by the flash photolysis of the alkali-metal salts of the sulfonyl carbanion in the presence of neutral FlO and this was attributed to the ion pair structure of the sulfonyl carbanions. 相似文献
235.
236.
237.
Naoya Nishi Daisuke Hobara Masahiro Yamamoto Takashi Kakiuchi 《Analytical sciences》2003,19(6):887-890
Sum frequency vibrational spectra for hexadecanethiol (HDT) adsorbed on thin gold film deposited on the surface of a CaF2 prism have been measured using total-internal reflection broad-bandwidth sum frequency generation (TIR-BBSFG) spectroscopy. The bands attributed to the CH3 symmetric and asymmetric stretching vibrational modes were observed in the sum frequency vibrational spectra. The orientation of the methyl groups was analyzed using the ratio of the intensities of the two modes. The methyl groups of HDT on the thin gold film were much more randomly orientated than those on Au( 111). 相似文献
238.
Controlling spontaneous emission and threshold-less laser oscillation with optical microcavities 总被引:10,自引:0,他引:10
H. Yokoyama K. Nishi T. Anan Y. Nambu S. D. Brorson E. P. Ippen M. Suzuki 《Optical and Quantum Electronics》1992,24(2):S245-S272
We describe the alteration of spontaneous emission of materials in optical microcavities having dimensions on the order of the emitted wavelength. Particular attention is paid to one-dimensional optical confinement structures with pairs of planar reflectors (planar microcavities). The presence of the cavity causes great modifications in the emission spectrum and spatial emission intensity distribution accompanied by changes in the spontaneous emission lifetime. Experimental results are shown for planar microcavities containing GaAs quantum wells or organic dye-embedded Langmuir-Brodgett films as light emitting layers. Also discussed are the laser oscillation properties of microcavities. A remarkable increase in the spontaneous emission coupling into the laser oscillation mode is expected in microcavity lasers. A rate equation analysis shows that increasing the coupling of spontaneous emission into the cavity mode causes the disappearance of the lasing threshold in the input-output curve. Experimentally verification is presented using planar optical microcavities confining an organic dye solution. The coupling ratio of spontaneous emission into a laser mode increases to be as large as 0.2 for a cavity having a half wavelength distance between a pair of mirrors. At this point, the threshold becomes quite fuzzy. Differences between the spontaneous emission dominant regime and the stimulated emission dominant regime are examined with emission spectra and emission lifetime analyses. 相似文献
239.
Yoshitake Nishi Kazuo Nozaki Takuya Kurotaki 《Zeitschrift für Physik B Condensed Matter》1993,91(2):175-178
Influence of Ti addition (substitution for Bi) on Tc is studied for high Tc (Bi1-zTiz)1.6Pb0.4Sr2Ca2Cu3Ox. We found a critical Ti addition to keep high Tc (above 100 K) of the (Bi1-zTiz)1.6Pb0.4Sr2Ca2Cu3Ox. The high-Tc phase can be found up to 0.5 of z. It is explained by an abnormal Tc change which is found from 0.3 to 0.5 of z. Based on results of the electrical resistivity and x-ray diffraction, an abnormal Tc change is discussed. 相似文献
240.
T Nishi F Tabusa T Tanaka T Shimizu K Nakagawa 《Chemical & pharmaceutical bulletin》1985,33(3):1140-1147