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71.
Vadim A. Soloshonok Hironari Ohkura Manabu Yasumoto 《Journal of fluorine chemistry》2006,127(7):930-935
An asymmetric synthesis of (S)- and (R)-3-amino-4,4,4-trifluorobutanoic acid via DBU-catalyzed asymmetric 1,3-proton shift transfer reaction of (Z)-3-[(R)-1-phenylethylamino]-4,4,4-trifluoro-N-[(R)-1-phenylethyl]but-2-enamide has been developed. The intermediate Schiff base (S,R′)-9 was found to be relatively configurationally stable under the highly basic reaction conditions allowing preparation of the target amino acid in high chemical yield and enantioselectivity. This method was demonstrated to be practical for large (>25 g) scale synthesis of the target β-amino acid. 相似文献
72.
We investigated quantized modes of kinks in the phase space of superconducting gaps in a superconductor with multiple gaps. The kink is described by the sine-Gordon model in a two-gap superconductor and by the double sine-Gordon model in a three-gap superconductor. A fractional-flux vortex exists at the edge of the kink, and a fractional-flux vortex will be stable in a three-gap superconductor with time-reversal symmetry breaking. The kink and fractional-flux vortex exhibit massless modes as a sliding motion. We show further that there are one zero-energy mode (massless mode) and quantized excitation modes in kinks, which are characteristic features of multi-gap superconductors. The equation of quantized modes for the double sine-Gordon model is solved numerically. The correction to the ground-state energy is calculated based on the renormalization theory. 相似文献
73.
Wavelet processing and digital interferometric contrast to improve reconstructions from X‐ray Gabor holograms
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Juan C. Aguilar Masaki Misawa Kiyofumi Matsuda Yoshio Suzuki Akihisa Takeuchi Masato Yasumoto 《Journal of synchrotron radiation》2018,25(3):808-817
In this work, the application of an undecimated wavelet transformation together with digital interferometric contrast to improve the resulting reconstructions in a digital hard X‐ray Gabor holographic microscope is shown. Specifically, the starlet transform is used together with digital Zernike contrast. With this contrast, the results show that only a small set of scales from the hologram are, in effect, useful, and it is possible to enhance the details of the reconstruction. 相似文献
74.
Uchiyama T Miyoki S Telada S Yamamoto K Ohashi M Agatsuma K Arai K Fujimoto MK Haruyama T Kawamura S Miyakawa O Ohishi N Saito T Shintomi T Suzuki T Takahashi R Tatsumi D 《Physical review letters》2012,108(14):141101
The thermal fluctuation of mirror surfaces is the fundamental limitation for interferometric gravitational wave (GW) detectors. Here, we experimentally demonstrate for the first time a reduction in a mirror's thermal fluctuation in a GW detector with sapphire mirrors from the Cryogenic Laser Interferometer Observatory at 17 and 18 K. The detector sensitivity, which was limited by the mirror's thermal fluctuation at room temperature, was improved in the frequency range of 90 to 240 Hz by cooling the mirrors. The improved sensitivity reached a maximum of 2.2×10(-19) m/√Hz at 165 Hz. 相似文献
75.
Kiyoharu Tadanaga Akira Miyata Daisuke Ando Naoko Yamaguchi Masahiro Tatsumisago 《Journal of Sol-Gel Science and Technology》2012,62(1):111-116
Using hot water treatment of sol–gel derived precursor gel films, Co–Al and Ni–Al layered double hydroxide (LDH) thin films
were prepared. The precursor gel films of Al2O3–CoO or Al2O3–NiO were prepared from cobalt or nickel nitrates and aluminum tri-sec-butoxide using the sol–gel method. Then, the precursor gel films were immersed in a NaOH aqueous solution of 100 °C. Nanocrystallites
of Co–Al and Ni–Al LDH were precipitated with the hot water treatment with NaOH solution. The largest amounts of nanocrystals
were obtained with a solution of pH = 10 for Co–Al LDH, and with that of pH = 9 for Ni–Al LDH. X-ray diffraction measurements
confirmed that this process formed CO3
2− intercalated LDHs. Both Co–Al and Ni–Al LDH thin films were confirmed to work as electrodes for electrochemical devices by
cyclic voltammogram measurements. 相似文献
76.
In the present study, all-trans retinoic acid (RA) gels formulated with various compositions of polyethylene oxide (Emulgen?) and iota-carrageenan (ι-CG) were prepared and their physicochemical properties were evaluated. The compression energy, which is the work required to compress the product through a fixed distance, increased with increasing amount of ι-CG or Emulgen?. The adhesion energy and displacement decreased with increasing amount of ι-CG or Emulgen? due to the progression of gel formation. From the results of the sensory tests, the properties of RA gels such as adhesiveness, gel strength and spreadability seemed to be adjustable depending on the condition of skin by varying the components of RA gels. Through photostability study, the expiration date and storage conditions of RA gels were determined as "4°C for 28?d with no exposure to light." 相似文献
77.
Yoshimi Ohmae Natsuko I. Kobayashi Keitaro Tanoi Atsushi Hirose Takayuki Saito Akihiko Noda Naoko Iwata Akimasa Nakano Satoru Nakamura Tomoko M. Nakanishi 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(1):241-244
The mineral composition of frozen food of taro [Colocasia esculenta (L.) Schott] was analyzed to categorize the geographical production place of taro. The concentrations of Co and H2PO4
− were found to be useful to separate the producing place between Japan and China. The analysis was performed by instrumental
neutron activation analysis (INAA) and ion chromatography (IC). In the case of INAA, the samples were dried and sealed in
a vinyl bag and irradiated with thermal neutrons from JRR3M, installed at Japan Atomic Energy Agency (JAEA). The activated
samples were cooled down for a few weeks and the elements (Co, Cr, Fe, Rb, Zn) were determined. Cobalt concentration of frozen
taro from China was higher than that from Japan. The tendency was the same in the fresh sample of taro. When concentration
of H2PO4
− of frozen sample was measured, taro from Japanese product was higher than that of Chinese one, contrary to fresh sample.
This result might be caused by the leakage of H2PO4
− during freezing process, indicating that we should be careful to apply the discrimination indicators. In addition to Co,
there was a significant difference of Rb and Fe concentrations between frozen taro from Japan and China. 相似文献
78.
Naoko Asakuma Toshimi Fukui Mamoru Aizawa Motoyuki Toki Hiroaki Imai Hiroshi Hirashima 《Journal of Sol-Gel Science and Technology》2000,19(1-3):333-336
Structural changes stimulated by ultraviolet (UV) laser irradiations of sol-gel derived inorganic oxide films were investigated. Dried gel films of TiO2, Nb2O5, Ta2O5, SrTiO3 and Pb(Zr
x
Ti1–x
)O3 (PZT) were found to be crystallized by the laser irradiation. On the other hand, the photo-induced change in gel films of BaTiO3, LiNbO3 and LiTaO3 was not observed although the laser beams were absorbed in the films. These sol-gel films were thermally crystallized at almost the same temperature around 600–700°C except TiO2. Thus, the UV-laser-induced crystallization is not directly ascribed to a simple thermal effect with the irradiation. Photochemical properties of the cations are assumed to be important for the change in sol-gel films. 相似文献
79.
Masahiro Yasumoto 《Archive for Mathematical Logic》2005,44(6):685-688
We prove that PTCN(n) (the polynomial time closure of the nonstandard natural number n in the model N of S2.) cannot be a model of U12. This implies that there exists a first order sentence of bounded arithmetic which is provable in U12 but does not hold in PTCN(n). 相似文献
80.
Naoko Asakuma Hiroshi Hirashima Hiroaki Imai Toshimi Fukui Motoyuki Toki 《Journal of Sol-Gel Science and Technology》2003,26(1-3):181-184
Structural changes in sol-gel films with photo-irradiation were investigated using zinc oxide (ZnO) derived from zinc acetate. The exposure of the films to an ultraviolet lamp induced hexagonal ZnO crystals in a relatively dense amorphous structure. On the other hand, the formation of zinc metal was found in a porous gel film. The photo-induced crystallization and reduction are ascribed to the electronic excitation in the metastable non-crystalline states. 相似文献