Correlation between transition temperature, in-plane copper-oxygen bond length, and tilt/buckling of the CuO2 plane in cuprate superconductors

Correlation among transition temperature, in-plane Cu-O bond length, and tilt/buckling in cuprate superconductors were examined in detail. As for cuprates with a single CuO_2 layer, tilt structure was observed in the region, whose in-plane Cu-O length was 1.906-1.926 Å, and that the tilt structure drastically suppressed superconductivity. As for cuprates with double CuO_2 layers, all the compounds had buckling distortion in a CuO_5 pyramid. The degree of distortion was determined only by a kind of cation between the two facing CuO_5 pyramids, that is, calcium or yttrium. A higher transition temperature was obtained for a copper oxide with having larger Cu-O length and smaller buckling degree. A common feature of layered cuprates was the existence of three major classes distinguished by the cations Ba^, Sr^, and Ln^ occupying the 9-coordination sites

Electron Diffraction Study on CuAu at Temperatures Above the Transition Point of Order-Disorder

Using a high temperature electron diffraction camera and thin oriented, evaporated films, the structure of CuAu has been investigated mainly at temperatures above the transition point of order-disorder. When the temperature exceeds the transition point, strong superlattice reflections of CuAu (II) vanish and weak, diffuse maxima appear at superlattice reflection positions, those at {110} positions showing peculiar shape characteristic of anti-phase domains, over the temperature range of about 50℃ above the transition point. It is inferred that short chains of domains with the anti-phase character which is the same as the character in CuAu (II) but much more degenerate than this are present sporadically in the lattice in the equilibrium state in this temperature range

Power Spectrum Density of long-term MAXI data

Monitor of All-sky X-ray Image (MAXI) on the International Space Station has been observing the X-ray sky since 2009 August 15. It has accumulated the X-ray data for about four years, so far. X-ray objects are usually variable and their variability can be studied by the power spectrum density (PSD) of the X-ray light curves.We applied our method to calculate PSDs of several kinds of objects observed with MAXI. We obtained significant PSDs from 16 Seyfert galaxies.For blackhole binary Cygnus X-1 there was a difference in the shape of PSD between the hard state and the soft state. For high mass X-ray binaries, Cen X-3, SMC X-1, and LMC X-4, there were several peaks in the PSD corresponding to the orbital period and the superorbital period.Comment: 4 pages, 4 figures, accepted for proceedings of The 12th Asia Pacific Physics Conference of AAPP

Chemical studies on fish solubles I. : Vitamin contents and amino acid composition of commercial fish solubles

(1) 市販フィッシユソルプノレ7種についてそれらの一般分析，窒素分布，ビタミン含量，アミノ酸組成等の測定を行なって，その栄養価値を比較検討した. (2) 窒素分布は，一般に水溶性， 5% TCA可溶性窒素ともに総窒素の80%以上であるが， 80% EtOH可溶性窒素は50%程度を占めるにすぎない. (3) ビタミン含量は無水物g当りB2 0.8~2 1.5γ， B6 0 .4~8.1γ， pantothenic acid 5.4~76.4γ， niacin 149~1120γ， biotin 19.4~2110mγ， B12 218~3930mγ， choline 331~6120γと製品により相当な差がある. (4) 遊離アミノ酸量はTCA可溶部の5%程度のものがl例，ほぼ50%遊離化されているものが1例で，他はその中間であり，概して遊離アミノ酸は少い. (5) アミノ酸組成からは製品を3種にわけられるようである.すなわち. (a) TCA可溶部がコラーゲンのアミノ酸組成に ，沈澱部が肉蛋白のそれに類似するもの. (防両画分ともコラーゲン類似のもの，(c) 両区分とも肉蛋白類似のものである.試料A， B， Eは(a)に，G は(b)に，Cは(C)に 相当した. (6) したがって，ソルプルの栄養価値の評価ならびに品質の判定には，ビタミン含量とともに，そのアミノ酸組成を知らねばならない.Because various kinds of raw materials and processing methods are used in the commercial production of the fish soluble, the quality and nutritive constituents of the products have wide variabilities. In recent years HIGASHI et al. have reported on the vitamin contents and mineral compositions of commercial fish solubles, but it seems that their work dealt with amino acid composition only to a limit extent. In the present work, the authors have examined several commercial fish solubles with regard to amino acid composition as well as nitrogen distribution and vitamin contents. The results of the analyses of seven samples are summarized as follows; (1) As shown in Table 2, the proportion of volatile basic nitrogen to total nitrogen varied widely from sample to sample, ranging from 4.2 to 11.6%. Although both water soluble nitrogen and 5% TCA soluble nitrogen exceeded 80% of total nitrogen in every sample, 80% EtOH soluble nitrogen occupied only about 50% of total nitrogen. (2) Contents of the vitamins of B group varied widely within the following ranges: vitamin B2, 0.8-21.5γ; vitamin B6, 0.4-8.1γ; pantothenic acid, 5.4-76.4γ; niacin, 149-1120γ; biotin, 19.4-2110mγ; B12 , 218-3930mγ and choline 331--6120γ per g. of dry matter. (3) In general the content of free amino acid was considerably small, with the exception of sample C in which free amino acids occupied about 58% of TCA soluble fraction. (4) Fish solubles can be classified into three classes, according to their amino acid composition: (a) Amino acid compositions of TCA soluble fraction and precipitate fraction are respectively, quite alike to that of collagen and of fish muscle proteins; (b) amino acid compositions of both fractions are similar to that of collagen; (c) amino acid compositions of both fractions are similar to that of fish muscle proteins.本研究費の一部は文部省科学試験研究貸補助金によったものである

Neutron scattering study on spin correlations and fluctuations in the transition-metal-based magnetic quasicrystal Zn-Fe-Sc

Spin correlations and fluctuations in the 3d-transition-metal-based icosahedral quasicrystal Zn-Fe-Sc have been investigated by neutron scattering using polycrystalline samples. Magnetic diffuse scattering has been observed in the elastic experiment at low temperatures, indicating development of static short-range-spin correlations. In addition, the inelastic scattering experiment detects a $Q$-independent quasielastic signal ascribed to single-site relaxational spin fluctuations. Above the macroscopic freezing temperature $T_{\rm f} \simeq 7$ K, the spin relaxation rate shows Arrhenius-type behavior, indicating thermally activated relaxation process. In contrast, the relaxation rate remains finite even at the lowest temperature, suggesting a certain quantum origin for the spin fluctuations below $T_{\rm f}$.Comment: To be published in Phys. Rev.