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Yoshio Kitaoka Hidekazu Mukuda Shin-ichiro Tabata Akira Iyo 《Journal of Physics and Chemistry of Solids》2011,72(5):486-491
We reexamine the novel phase diagrams of antiferromagnetism (AFM) and high-Tc superconductivity (HTSC) for a disorder-free CuO2 plane based on an evaluation of local hole density (p) by site-selective Cu-NMR studies on multilayered copper oxides. Multilayered systems provide us with the opportunity to research the characteristics of the disorder-free CuO2 plane. The site-selective NMR is the best and the only tool used to extract layer-dependent characteristics. Consequently, we have concluded that the uniform mixing of AFM and SC is a general property inherent to a single CuO2 plane in an underdoped regime of HTSC. The T=0 phase diagram of AFM constructed here is in quantitative agreement with the theories in a strong correlation regime which is unchanged even with mobile holes. This Mott physics plays a vital role for mediating the Cooper pairs to make Tc of HTSC very high. By contrast, we address from extensive NMR studies on electron-doped iron-oxypnictides La1111 compounds that the increase in Tc is not due to the development of AFM spin fluctuations, but because the structural parameters, such as the bond angle α of the FeAs4 tetrahedron and the a-axis length, approach each optimum value. Based on these results, we propose that a stronger correlation in HTSC than in FeAs-based superconductors may make Tc higher significantly. 相似文献
45.
Wavelet processing and digital interferometric contrast to improve reconstructions from X‐ray Gabor holograms 下载免费PDF全文
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
46.
Direct Monitoring of Thickness and Refractive Index of Optical Thin Film Deposited on Fiber End-face
We propose a system for depositing thin films on waveguides which enables low-temperature deposition and precise control of the refractive index and film thickness. It is composed of a conventional ion-beam sputtering (IBS) system and a new system for directly monitoring film characteristics during deposition. We controlled refractive indices over a wide range from 1.52 to 1.97 by moving the sputtering targets (SiO2 and Si3N4) in the IBS system. The refractive index or film thickness was in-situ monitored by observing the optical power reflected from the end-face of a monitoring fiber set in the deposition chamber. Antireflection coating films were successfully deposited on a fiber end-face and a laser diode chip facet with low reflectivity from 0.05 to 0.07%. This deposition system is attractive for constructing highly functional optical devices for future photonic networks. 相似文献
47.
J. Vacík J.
erven V. Hnatowicz D. Fink Y. Kobayashi K. Hirata P. Yu. Apel P. Strauss 《Radiation measurements》1999,31(1-6):81-84
A recently suggested technique for non-destructive investigation of inhomogeneities in thin objects, which is based on the measurement of the energy spectra of charged particles transmitted through the object, is used for the study of thermal annealing of 10–20 μm thick polyethylene terephtalate, polypropylene and polycarbonate foils irradiated with 1–10 MeV/amu heavy ions. At elevated temperature a foil linear contraction is observed on pristine and irradiated material. Also the foil roughness increases with increasing temperature. On the same foils with etched pores 0.5–1.0 μm in diameter, the thermal annealing results in gradual closing of the pores up to about 30% of their initial diameter at the temperatures of 150–175°C. At higher temperatures the pore diameter increases and achieves its initial value. 相似文献
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Tadamasa Toma Yoshio Furuya Wataru Watanabe Kazuyoshi Itoh Junji Nishii Kenichi Hayashi 《Optical Review》2000,7(1):14-17
It is known that local refractive index change occurs when femtosecond laser pulses with extremely high peak power are launched into glass. We focused 130-femtosecond laser pulses of 800 nm into the bulk of glass and examined the shape of the induced refractive index change. We found that the length of the spot of the refractive index change along the optical axis reached about 30 μm despite the diameter being about 2 μm. To estimate the distribution of induced refractive index change, we fabricated Bragg grating by scanning the focused spot and calculated the amount of the change by applying Kogelnik’s coupled mode theory to the measured diffraction efficiencies of the higher order diffracted beams. 相似文献
49.
Yoshio Mimura 《Journal of Number Theory》1983,16(1):138-146
Apéry introduced a recurrence relation for a proof of the irrationality of ζ(3). Let an (n ≥ 0) satisfy the relation n3an ? (34n3 ? 51n2 + 27n ? 5)an ? 1 + (n ? 1)3an ? 2 = 0. Which values of a0 and a1 cause each an to be an integer? This question is answered and some congruence properties of the an are given. 相似文献
50.
We demonstrated important changes produced on the modulation frequency of hybrid organic–inorganic light‐emitting diodes to examine the applicability as a light source for visible optical communications. The fabricated device structure was 4,4′‐bis[N ‐(1‐napthyl)‐N ‐phenyl‐amino]biphenyl/4,4′‐(bis(9‐ethyl‐3‐carbazovinylene)‐1,1′‐biphenyl:4,4′‐bis[9‐dicarbazolyl]‐2,2′‐biphenyl/ZnS/LiF/MgAg. This device showed an improvement in the modulation frequency using ZnS instead of an organic material, tris(8‐hydroxyquinoline)aluminum. A maximum cutoff frequency of 20.6 MHz was achieved.