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排序方式: 共有253条查询结果,搜索用时 15 毫秒
1.
Ryohei Tsuda Sayaka Kaino Hisashi Kokubo Shin-Ichiro Imabayashi Masayoshi Watanabe 《Colloids and surfaces. B, Biointerfaces》2007,56(1-2):255-Optics
Redox properties of phenothiazine-labeled poly(ethyl glycidy ether)-block-poly(ethylene oxide) (PT-EGEn-b-EOm) are reversibly changed by core-shell micelle formation. In the temperature range higher than the critical micellization temperature (cmt), the anodic potential of PT group positively shifts and concomitantly its anodic current decrease, or levels off compared to those of the reference polymer PT-EOm without the thermo-responsive EGEn segment. The former alteration is caused by incorporation of hydrophobic PT groups into a core of the micelle and the latter by the decrease in the diffusion coefficient of PT groups due to formation of the core-shell micelles. The cmt value and the temperature-dependent alteration in the redox properties strongly depend on the polymer structure, especially the length of thermo-responsive EGEn segment. The electrochemically determined hydrodynamic radii of the polymer aggregates seem to be overestimated, compared to the values reported for the aggregates of other thermo-responsive polymers with similar molecular weights, implying the presence of electrochemically inactive PT groups in the copolymers having longer thermo-responsive segments. 相似文献
2.
Tatsuo Nakagawa Satoshi Fukura Munenori Nakai Kazumasa Sugiyama Ryohei Kokawa Hiroyuki Kagi 《Optical Review》2006,13(4):269-275
We constructed a scanning near-field optical microscope (SNOM) on a commercially available atomic force microscopy (AFM) apparatus
(SPM-9500J2; Shimadzu Corp.) to measure the stress distribution in ceramic composite materials. Features of our SNOM system
are: (1) a compact SNOM head substituted for the original AFM head; (2) a wide scanning range (125 × 125 μm2) inherited from the original scanner; (3) use of conventional shear-force regulation; (4) an optical system for the illumination-collection
(I-C) mode; (5) excitation by a 488 nm line of an Ar-ion laser, and (6) light detection by photon counting or a polychromator
equipped with an electronically cooled charge coupled device (CCD). This SNOM system was used to measure the surface structure
and stress distribution of an Al2O3/ZrO2 eutectic composite. We simultaneously measured topographic images and fluorescence spectra of an Al2O3/ZrO2 eutectic composite. We estimated its peak intensity, peak position, and peak width from the fluorescence spectrum during
scanning, which respectively correspond to the abundance of Al2O3, stress in the grain, and the anisotropy of that stress. Mapping images showed that the stress and its anisotropy were weaker
in the center of the Al2O3 grain than its boundary between Al2O3 and ZrO2. That observation suggests that Al2O3 underwent intense anisotropic stress induced by volume expansion in the phase transition of ZrO2 from the cubic phase to the monoclinic phase during preparation. 相似文献
3.
We present a divergence-free WKB theory, which is a new semiclassical theory modified by nonperturbative quantum corrections. Conventionally, the WKB theory is constructed upon a trajectory that obeys the bare classical dynamics expressed by a quadratic equation in momentum space. Contrary to this, the divergence-free WKB theory is based on a higher-order algebraic equation in momentum space, which represents a dressed classical dynamics. More precisely, this higher-order algebraic equation is obtained by including quantum corrections to the quadratic equation, which is the bare classical limit. An additional solution of the higher-order algebraic equation enables us to construct a uniformly converging perturbative expansion of the wavefunction. Namely, our theory removes the notorious divergence of wavefunction at a turning point from the WKB theory. Moreover, our theory is able to produce wavefunctions and eigenenergies more accurate than those given by the traditional WKB method. In addition, the divergence-free WKB theory that is based on the cubic equation allows us to construct a uniformly valid wavefunction for the nonlinear Schrödinger equation (NLSE). A recent short letter [T. Hyouguchi, S. Adachi, M. Ueda, Phys. Rev. Lett. 88 (2002) 170404] is the opening of the divergence-free WKB theory. This paper presents full formalism of this theory and its several applications concerning wavefunction and eigenenergy to show that our theory is a natural extension of the traditional WKB theory that incorporates nonperturbative quantum corrections. 相似文献
4.
Ryohei Hanayama Kenichi Hibino Shin’ichi Warisawa Mamoru Mitsuishi 《Optical Review》2004,11(5):337-343
Wavelength scanned interferometry allows the simultaneous measurement of top surface shape and optical thickness variation of a transparent object consisting of several parallel surfaces. Interference signals from these surfaces can be separated in frequency space, and their phases are detected by discrete Fourier analysis. However, these signal frequencies are shifted from the detection frequency by the refractive index dispersion of the object and a nonlinearity of the wavelength scanning. The Fourier analysis is sensitive to the detuning of the signal frequency and suffers from the multiple-beam interference noise. Conventional error-compensating algorithms cannot be applied to an object consisting of more than three reflecting surfaces. We derive a new 2N-1 sample error-compensating algorithm, which allows the phase detection of any order of harmonic frequency among the interference signals. The new algorithm suppresses the effect of signal frequency detuning as well as the multiple-beam interference noise and can be applied to the measurement of complex objects consisting of more than three reflecting surfaces. 相似文献
5.
Ryosuke Sakai Issei Otsuka Toshifumi Satoh Ryohei Kakuchi Harumi Kaga Toyoji Kakuchi 《Journal of polymer science. Part A, Polymer chemistry》2006,44(1):325-334
The asymmetric polymerization of 4′‐isocyanatobenzo‐18‐crown‐6 with the lithium amide of (S)‐(2‐methoxymethyl)pyrrolidine successfully proceeded to afford end‐functionalized poly(4′‐isocyanatobenzo‐18‐crown‐6) with (S)‐(2‐methoxymethyl)pyrrolidine (polymer 2 ). In the circular dichroism (CD) spectrum of 2 , a clear positive Cotton effect was observed in the range of 240–350 nm corresponding to the absorption of the polymer backbone, indicating that 2 partially formed a one‐handed helical structure, which was preserved by the chirality of (S)‐(2‐methoxymethyl)pyrrolidine bonding to the terminal end in 2 . In the titration experiments for the CD intensity of 2 in the presence of D ‐ and L ‐Phe·HClO4 (where Phe is phenylalanine), a small but remarkable difference was observed in the amount of the chiral guest needed for saturation of the CD intensity and in the saturated CD intensity, indicating that the extremely stable, one‐handed helical part should exist in the main chain of 2 , which was not inverted even when the unfavorable chiral guest for the predominant helical sense, L ‐Phe·HClO4, was added. In addition, helical polymer 2 exhibited a chiral discrimination ability toward racemic guests; that is, the guests were extracted from the aqueous phase into the organic phase with enantiomeric excess. The driving force of the chiral discrimination ability of 2 should certainly be attributed to the one‐handed helical structure in 2 . © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 325–334, 2006 相似文献
6.
Tatsuo Nakahara Kinsi Motomura Ryohei Matuura 《Journal of Polymer Science.Polymer Physics》1966,4(4):649-657
The crystallization kinetics of poly(n-octadecyl methacrylate) has been studied at the air–water interface. The rate of the crystallization has been measured by the decrease in the area of monolayers with time at various temperatures and surface pressures. The crystallization isotherms have been analyzed by the general mathematical treatment of the kinetics of phase changes, and the results show linear growth to be dominant. The variation of the rate constant with temperature and pressure has been illustrated by the difference in the supersaturation defined by introducing the equilibrium pressure-area isotherms. 相似文献
7.
Manganese (Mn), iron (Fe), copper (Cu), and zinc (Zn) concentrations were determined in the brain regions of normal 1-, 3-, 5-, 7-, 14-, 21-, 42-, 77-, and 147-day-old Wistar rats using inductively coupled plasma mass spectrometry (ICP-MS), and their maps were illustrated in color to visually compare the distribution of the elements at various stages of the growth process. Sagittal slices (1-mm thickness) sectioned at the level of the substantia nigra were divided into 18 regions, and the small slice samples were digested in microwave-assisted closed vessels for ICP-MS measurement. Mn, Fe, Cu, and Zn concentrations increased region-specifically with age, and their distributional maps showed some characteristics. These findings are discussed in terms of needs for these trace elements in the normal brain. Among new findings about their brain distribution, it is especially noteworthy that higher concentrations of Mn, Fe, and Zn were observed in the substantia nigra compared with those in neighboring regions. The mapping method in this work is expected to open up possibilities for screening of the in vivo element–element interrelationships among these essential elements. 相似文献
8.
Stereoselective polymerization of racemic lactide (rac-LA) was examined using Al-achiral ligand complexes. By introduction of substituents in aromatic rings of Schiff base ligands, a higher selectivity was obtained without any chiral auxiliaries in the catalyst via a chain-end control mechanism. The T(m) values (T(m) 170-192 degrees C) were comparable to or higher than that of homochiral polymer, poly(L-LA) (T(m) 162 degrees C), and a thermally more stable polylactide than poly(L-LA) was prepared from rac-LA. 相似文献
9.
Monolayer properties of irisresorcinol [5-(cis-10-heptadecenyl) resorcinol] were measured at the air/water interface. TheA-T isobars of the monolayers at 10 and 15 mN/m gave two-dimensional thermal expansivities of 1.4 × 10–4/K and 1.3 × 10–4/K at a temperature span from 7–40 C, respectively. The- A isotherms of the material showed only a little dependence on temperature from 5–35 C and onpH except at highpH, where monolayers expanded by ionization of resorcinol headgroups. Some types of saccharose in the subphase exhibited a characteristic interaction with irisresorcinol in monolayers, and there is a possibility that this material will be used for molecular recognition of some saccharoses. 相似文献
10.
The interfacial tension of aqueous dodecyltrimethylammonium chloride (DTAC) solution/hexane interface has been measured as a function of pressure at concentrations around the critical micelle concentration (CMC). The derivative of the interfacial tension with respect to pressure has been observed to change abruptly at the CMC as in the case of aqueous dodecylammonium chloride (DAC) solution-hexane system studied already. The volume changes associated with the adsorption of DTAC from its monomeric and micellar states have been calculated. The results have indicated that the micelle formation of surfactant is treated like the appearance of a new macroscopic phase in the system. It has also been concluded that the micelle solubilizing hexane bears resemblance to the adsorbed film in terms of the volume. The difference in the pressure dependence of the volume of micelle formation
MW between DTAC and DAC has been attributed to a larger polar group of DTAC. The fact that the value of
MW is larger than that estimated from the conductivity data has been explained by the solubilization of hexane into the micelle. 相似文献