High-pressure and high-temperature synthesis of heavy lanthanide sesquisulfides Ln2S3 ( Ln=Yb and Lu)

Detailed pressure-temperature phase diagrams of heavy lanthanide sesquisulfides Ln2S3 (Ln = Yb and Lu) have been investigated by in-situ x-ray diffraction experiments under high pressure and high temperature using synchrotron radiation and multi-anvil press. Based on the results of the in-situ observation, the single γ-phase (Th3P4-type structure, I3d) samples of Ln2S3 (Ln = Yb and Lu) have been synthesized under high pressure. The physical properties of the compounds were studied by electrical resistivity, specific heat, and magnetic susceptibility measurements between 2 K and 300 K

異なる養生温度と養生期間に於けるシリカフュームを添加したハイアルミナセメント水和物中のストラトリンジャイトの結晶化について

広島大学(Hiroshima University)博士(理学)Doctor of Sciencedoctora

Socioeconomic status and self-rated health of Japanese people, based on age, cohort, and period

Background: Differences in health resulting from differences in socioeconomic status (SES) have been identified around the world. Age, period, and cohort (A-P-C) differences in health are vital factors which are associated with disparities in SES. However, few studies have examined these differences simultaneously. Moreover, although self-rated health (SRH) has been frequently used as an indicator of health, biases in reporting SRH that depend on the socioeconomic characteristics of respondents have been scarcely adjusted in the previous studies. To overcome these limitations, we investigated the associations between disparities in SES and adjusted SRH based on A-P-C, by using a repeated, cross-sectional survey of a nationally representative sample of Japanese people. In addition, we further investigated how exogenous (macroeconomic) conditions unique to a period or cohort would explain trends across successive periods and cohorts. Methods: Data were obtained from a sample of 653,132 Japanese people that responded to the Comprehensive Survey of Living Conditions (CSLC), which is a cross-sectional survey that had been conducted every three years from 1986 to 2013, on over 10 occasions. In the CSLC, SES has been assessed by household income. We simultaneously controlled for each A-P-C dimension by using the model for cross-classification of random effects, and adjusting SRH data for reporting biases caused by differences in income and A-P-C. Results: Differences in adjusted SRH associated with income differences decreased with age and reversed after 76 years of age. Period differences indicated that income differences peaked in 1992 and 2007. Moreover, differences in adjusted SRH associated with income differences decreased in periods with high unemployment across all periods. Furthermore, there were no cohort differences in adjusted SRH that were associated with income differences. Conclusion: In Japan, there are age and period variations associated with adjusted differences in SRH as assessed by income. Moreover, exogenous conditions in each period could help explain periodic trends across successive periods

The Bird Fauna in the Higashi-Hiroshima Campus of the Hiroshima University <Data>

広島県東広島市に所在する広島大学東広島キャンパスの鳥類相の把握を目的として,2010-2011 年にラインセンサス法を用いた野外調査を実施した。本キャンパスは,3 つのため池が存在し,それらが小さな河川で繋がり周辺には緑地帯が広がっていた。周年にわたる毎月の調査により11 目27 科55 種1628 羽の野鳥を確認した。その渡り区分は,留鳥58%,冬鳥29%,夏鳥9%,旅鳥4%であった。浅い水辺を利用する鳥類が少ない一方,カモ類や森林性の鳥類等が多く確認されたことから,本キャンパスのため池や森林,校舎が東西の山林をつなぐコリドー(緑の回廊)や渡りの中継地等の重要な役割を果たしていると考えられた

Wear resistance of nano-polycrystalline diamond with various hexagonal diamond contents

Wear resistance of nano-polycrystalline diamond (NPD) rods containing various amounts of hexagonal diamond has been tested with a new method for practical evaluation of the wear–resistance rate of superhard ceramics, in addition to the measurements of their Knoop hardness. The wear resistance of NPD has been found to increase with increasing synthesis temperature and accordingly decreasing proportion of hexagonal diamond. A slight increase in Knoop hardness with the synthesis temperature also has been observed for these samples, consistent with the results of the wear–resistance measurements. These results suggest that the presence of hexagonal diamond would not yield any observable increase in both hardness and wear resistance of NPD, contradictory to a recent prediction suggesting that hexagonal diamond is harder than cubic diamond. It is also demonstrated that NPD is superior to single crystal diamond in terms of relatively homogeneous wearing without any significant chipping/cracking.Зносостійкість нано-полікристалічних алмазних (НПА) стрижнів, з різним вмістом гексагонального алмазу, була протестована новим методом практичної оцінки швидкості зносу надтвердої кераміки, додатково до вимірюваня їх твердості по Кнупу. Було виявлено, що зносостійкість НПА збільшується зі зростанням температури синтезу і, відповідно, зі зменшенням частки гексагональних алмазів. Також, відповідно до результатів вимірювань зносостійкості, для цих зразків спостерігалося невелике збільшення твердості по Кнупу з температурою синтезу. Ці результати дозволяють припустити, що присутність гексагональних алмазів не приводить до будь-якого помітного збільшення як твердості, так і зносостійкості НПА, що суперечить недавньому припущенню про те, що гексагональний алмаз твердіший, ніж кубічний. Також показано, що НПА перевершує монокристал алмазу з точки зору відносно однорідного зношування без значних відколів/тріщин.Износостойкость нано-поликристаллических алмазных (НПА) стержней, с различным содержанием гексагонального алмаза, была протестирована новым методом практической оценки скорости износа сверхтвердой керамики, в дополнение к измерениям их твердости по Кнупу. Было обнаружено, что износостойкость НПА увеличивается с ростом температуры синтеза и, соответственно, с уменьшением доли гексагональных алмазов. Также, в соответствии с результатами измерений износостойкости, для этих образцов наблюдалось небольшое увеличение твердости по Кнупу с температурой синтеза. Эти результаты позволяют предположить, что присутствие гексагональных алмазов не приводит к какому-либо заметному увеличению как твердости, так и износостойкости НПА, что противоречит недавнему предположению о том, что гексагональный алмаз тверже, чем кубический. Также показано, что НПА превосходит монокристалл алмаза с точки зрения относительно однородного изнашивания без значительных сколов/трещин

Interplay of the electronic and lattice degrees of freedom in A_{1-x}Fe_{2-y}Se_{2} superconductors under pressure

The local structure and electronic properties of Rb$_{1-x}$Fe$_{2-y}$Se$_2$ are investigated by means of site selective polarized x-ray absorption spectroscopy at the iron and selenium K-edges as a function of pressure. A combination of dispersive geometry and novel nanodiamond anvil pressure-cell has permitted to reveal a step-like decrease in the Fe-Se bond distance at $p\simeq11$ GPa. The position of the Fe K-edge pre-peak, which is directly related to the position of the chemical potential, remains nearly constant until $\sim6$ GPa, followed by an increase until $p\simeq 11$ GPa. Here, as in the local structure, a step-like decrease of the chemical potential is seen. Thus, the present results provide compelling evidence that the origin of the reemerging superconductivity in $A_{1-x}$Fe$_{2-y}$Se$_2$ in vicinity of a quantum critical transition is caused mainly by the changes in the electronic structure

Interplay between local structure and electronic properties on CuO under pressure

The electronic and local structural properties of CuO under pressure have been investigated by means of X-ray absorption spectroscopy (XAS) at Cu K edge and ab-initio calculations, up to 17 GPa. The crystal structure of CuO consists of Cu motifs within CuO$_4$ square planar units and two elongated apical Cu-O bonds. The CuO$_4$ square planar units are stable in the studied pressure range, with Cu-O distances that are approximately constant up to 5 GPa, and then decrease slightly up to 17 GPa. In contrast, the elongated Cu-O apical distances decrease continuously with pressure in the studied range. An anomalous increase of the mean square relative displacement (EXAFS Debye Waller, \sigma$^2$) of the elongated Cu-O path is observed from 5 GPa up to 13 GPa, when a drastic reduction takes place in \sigma$^2$. This is interpreted in terms of local dynamic disorder along the apical Cu-O path. At higher pressures (P>13 GPa), the local structure of Cu$^{2+}$ changes from a 4-fold square planar to a 4+2 Jahn-Teller distorted octahedral ion. We interpret these results in terms of the tendency of the Cu$^{2+}$ ion to form favorable interactions with the apical O atoms. Also, the decrease in Cu-O apical distance caused by compression softens the normal mode associated with the out-of-plane Cu movement. CuO is predicted to have an anomalous rise in permittivity with pressure as well as modest piezoelectricity in the 5-13 GPa pressure range. In addition, the near edge features in our XAS experiment show a discontinuity and a change of tendency at 5 GPa. For P < 5 GPa the evolution of the edge shoulder is ascribed to purely electronic effects which also affect the charge transfer integral. This is linked to a charge migration from the Cu to O, but also to an increase of the energy band gap, which show a change of tendency occurring also at 5 GPa