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991.
In order to examine the flow behavior of polymer solutions through porous media, the measurement of pressure loss and the experiment for flow visualization were carried out with wavy channels as one of the model channels of porous media. The test fluids used are aqueous solutions of polyacrylamide (PAA) with two different concentrations. The occurrence of the excess pressure loss, which was not due to the effect of the centrifugal force, was found for the PAA solutions. The relations between the friction factor ratio and the Deborah number were similar to that obtained for the flow through porous media. Furthermore, the results of the flow visualization suggest that the elongational property of the PAA solutions is connected with the occurrence of the excess pressure loss. 相似文献
992.
We introduce a Vasicek-type short rate model which has two additional parameters representing memory effect. This model presents better results in yield curve fitting than the classical Vasicek model. We derive closed-form expressions for the prices of bonds and bond options. Although the model is non-Markov, there exists an associated Markov process that allows one to apply usual numerical methods to the model. We derive analogs of an affine term structure and term structure equations for the model, and, using them, we present a numerical method to evaluate contingent claims. 相似文献
993.
Enrico Bovero Dr. Kazuhisa Yano Dr. Tadashi Nakamura Yuri Yamada Frank C. J. M. van Veggel Prof. Dr. Ir. 《Chemphyschem》2010,11(12):2550-2554
The effects of the stop band (SB) in colloidal photonic crystals composed of silica spheres containing Eu3+‐ and Tb3+‐doped yttria nanoparticles are analysed. Reflection and transmission spectra indicate movement of the stop band, due to the 111 series of planes, towards shorter wavelengths with increasing angle of observation. The profile of the emission spectra is modified by the presence of the SB depending on the angle of measurement. Such a modification is more effective for a narrow emission band and it is thus more evident in the case of Tb3+ than Eu3+. An angular effect is also observed in the lifetime, which presents two maxima and one minimum. In the case of Tb3+ the maxima are at observation angles of 35 and 50°, and the minimum at 45°. We attribute this behaviour to penetration of the excitation beam at 475 nm modulated by the stop band. The ions excited in this way emit from different depths in the crystal, and therefore their lifetime will be affected differently by the same stop band, depending on the thickness of the crystal that must be crossed. Eu3+ shows a similar but less pronounced effect for two reasons: first, the main stop band (due to the 111 planes) is not effective at the excitation wavelength of 392 nm; second, the broadness of the Eu3+ emission is comparable to the width of the SB, and a decrease in the transition rate at the wavelength of the SB maximum is compensated by an increase at the sides of the SB. 相似文献
994.
Kenichi Murata Kazuki Kajiya Megumi Nukaga Yosuke Suga Toshiyuki Watanabe Nobuhumi Nakamura Hiroyuki Ohno 《Electroanalysis》2010,22(2):185-190
A simple method for constructing gold nanoparticle‐modified electrodes with three‐dimensional nanostructures is demonstrated. The electrodes were prepared by casting citrate‐reduced AuNPs onto polycrystalline gold electrodes. The resultant electrodes had a large surface area‐to‐volume ratio, adequate for high protein loading and conferring high stability. The gold nanoparticle electrodes were covered with a self‐assembled monolayer of 11‐mercaptoundecanoic acid for electrostatic immobilization of cytochrome c (cyt c). At the electrode, direct, reversible electron transfer from cyt c was observed with remarkable stability. Moreover, an extremely high surface coverage of electrochemically active cyt c, 167 fully packed monolayers, was obtained through use of the electrode. 相似文献
995.
Shin Nakamura Yorihiko Tsunoda Ippei Nomoto Hirohiko Sato 《Hyperfine Interactions》2010,197(1-3):101-104
In order to investigate the electronic state, the local structure, and the magnetic structure of a new ion oxide Fe3B7O13(OH), we have applied 57Fe Mössbauer spectroscopy. The room-temperature values of isomer shift and quadrupole splitting are 1.16 mm/s and 3.21 mm/s, respectively, which indicate that the Fe ions are in high spin Fe2?+? state. The spectrum at 4.2 K is composed of a well-resolved hyperfine sextet with the hyperfine field of 3.6 T. In a trimer, each Fe2?+? magnetic moment is supposed to be directed from Fe2?+? to OH???. 相似文献
996.
R. Kita S. Nakamura K. Sakimoto T. Nakamura O. Miura K. Matsumoto P. Mele K. Yamada K. Kaneko A. Ichinose 《Physica C: Superconductivity and its Applications》2010,470(20):1198-1200
We investigated the effects of indium doping on the superconducting properties of YBCO sintered samples and thin films. In2O3-doped YBCO and YBa2Cu3−xInxOy sintered samples showed a gradual decrease in the critical temperature (Tc) with increasing indium content; however, a Tc value above 80 K was maintained even up to 30 vol.% addition and x = 0.4, respectively. Ba3Cu3In4O12 was detected by X-ray diffractometry and energy-dispersive X-ray spectroscopy as a reaction product for both sintered samples. The normalized Jc under a magnetic field of 0.1 T showed a maximum at x = 0.3. Indium-doped YBCO films prepared by pulsed laser deposition showed a similar dependence of Tc on indium content as the sintered samples. 相似文献
997.
Phosphoester hydrolysis by cerium(IV)-thiacalix[4]arene complexes and its application to immunoassay
Hiroaki Matsumiya Hiroko Nakamura Masataka Hiraide 《Analytical and bioanalytical chemistry》2009,394(5):1471-1476
Thiacalix[4]arenetetrasulfonate was treated with Ce(IV) in water at pH 9.5 to give novel phosphoester-hydrolyzing complexes.
The dinuclear Ce(IV) complex promoted the hydrolysis of p-nitrophenyl phosphate with a turnover frequency of 6.8 h−1 at 50 °C, showing fourfold higher activity than the mononuclear complex. The dinuclear complex was readily immobilized onto
an antibody by simply mixing them in water, hence its phosphatase-like activity was applied to the color-developing reaction
in immunoassay. The model assay using an antibody labeled with the dinuclear complex allowed the detection of as little as
10 ng mL−1 of a tumor marker, Bence–Jones protein, in a 96-well microtiter plate format. Analysis of urine for Bence–Jones protein was
performed by the proposed method. 相似文献
998.
We report the synthesis of the novel fluorescence-labeled jasmonate glycoside 2 based on β-d-glucopyranosyl 12-hydroxyjasmonate 1, which is a leaf-closing substance of Albizzia julibrissin Durazz. The fluorescence study using 2 revealed that the target cell for 1 is a motor cell. Probe 2 bound to the motor cells of two plants belonging to genus Albizzia. This result suggested that a receptor for 2, which is common among genus Albizzia would be involved in the nyctinastic leaf movement. 相似文献
999.
Takamiya T Hosobuchi S Asai K Nakamura E Tomioka K Kawase M Kakutani T Paterson AH Murakami Y Okuizumi H 《Electrophoresis》2006,27(14):2846-2856
Restriction landmark genome scanning (RLGS) is a 2-DE of genomic DNA, which visualizes thousands of loci. In a conventional RLGS method for methylation analysis, we have used a methylation sensitive restriction enzyme, NotI as a landmark. However, it was unable to discriminate methylation polymorphism from sequence polymorphism. Here, we report an improved RLGS method to detect methylated sites directly. We employed isoschizomers, MspI and HpaII, that recognize the same sequence (CCGG) but have different methylation sensitivity. We carried out the RLGS analysis of Arabidopsis thaliana ecotype Columbia, and obtained a pair of spot patterns with MspI and HpaII. We detected 22 spots in both patterns. In comparison of them, 18% of the spots were polymorphic, which indicated the methylation of C(5m)CGG sites. Further analyses revealed an additional methylated site of NotI. Moreover, 52 and 54 restriction enzyme sites were also analyzed in two other ecotypes, Wassilewskija and Landsberg erecta, respectively. Consequently, 15% of the 52 common sites showed methylation polymorphism among the three ecotypes. The restriction sites analyzed in this study were located in or near genes, and contribute new data about the correlation between methylation status and gene expression. Therefore, this result strongly indicates that the improved RLGS method is readily applicable to practical analyses of methylation dynamics, and provides clues to the relationship between methylation and gene expression. 相似文献
1000.
Tahara K Yonemoto A Yoshiyama Y Nakamura T Aizawa M Fujita Y Nishikawa T 《Biomedical chromatography : BMC》2006,20(11):1200-1205
An HPLC-UV method was established for the determination of metformin and buformin in biological fluids. Metformin was not retained on particles packed in conventional solid-phase extraction cartridges; in contrast, buformin was retained too firmly and not eluted with a solvent for recovery. However, both drugs were retained on particles that had been treated with an ion-pair reagent of heptanesulfonate or dodecylsulfate and recovered almost completely. The recovered fraction was subjected to HPLC on a pentafluorophenylpropyl column which was suitable for the determination of both biguanides in serum and in urine. Limits of quantitation were low enough for clinical use, and reproducibility was high with an RSD of 0.9-2.3%. HPLC on a conventional octadecyl column was suitable only for the determination of buformin in serum since interfering peaks appeared on the chromatograms of urine samples. The method was applied to analysis of some clinical specimens. 相似文献