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131.
Matsuoka T Fujihisa H Hirao N Ohishi Y Mitsui T Masuda R Seto M Yoda Y Shimizu K Machida A Aoki K 《Physical review letters》2011,107(2):025501
Europium hydride EuH(x), when exposed to high-pressure H?, has been found to exhibit the following structural and valence changes: Pnma(x = 2, divalent) → P6?/mmc(x = 2, 7.2-8.7 GPa) → I4/m(x > 2, 8.7-9.7 GPa) → I4/mmm(x > 2, 9.7 GPa-,trivalent). With a trivalent character and a distorted cubic fcc structure, the I4/mmm structure is the β phase commonly observed for other rare-earth metal hydrides. Our study clearly demonstrates that EuH(x) is no longer an irregular member of the rare-earth metal hydrides. 相似文献
132.
Hisako Hirai Hirokazu Kadobayashi Takahiro Matsuoka Yasuo Ohishi Yoshitaka Yamamoto 《高压研究》2013,33(3):289-296
High pressure experiments were performed on D2O ice VII using a diamond anvil cell in a pressure range of 2.0–60 GPa at room temperature. In situ X-ray diffractometry revealed that the structure changed from cubic to a low symmetry phase at approximately 11 GPa, based on the observed splitting of the cubic structure's diffraction lines. Heating treatments were added for the samples to reduce the effect of non-hydrostatic stress. After heating, splitting diffraction lines became sharp and the splitting was clearly retained. Although symmetry and structure of the transformed phase have not been determined, change in volumes vs. pressure was calculated, assuming that the low-symmetry phase had a tetragonal structure. The bulk modulus calculated for the low-symmetry phase was slightly larger than that for the cubic structure. In Raman spectroscopy, the squared vibrational frequencies of ν1 (A1g), as a function of pressure, showed a clear change in the slope at 11–13 GPa. The full width at half maxima of the O-D modes decreased with increasing pressure, reaching a minimum at approximately 11 GPa, and increased again above 11 GPa. These results evidently support the existence of phase change at approximately 11 GPa for D2O ice VII. 相似文献
133.
Dr. Keiko Komori-Orisaku Dr. Olaf Stefańczyk Saori Ohishi Dr. Noriaki Ozaki Dr. Yasuto Miyamoto Dr. Kenta Imoto Prof. Shin-ichi Ohkoshi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(47):11066-11073
The self-assembly of cobalt(II) with purine and octacyanidotungstate(V) results in the formation of the three-dimensional Co3[W(CN)8]2(purine)2 ⋅ 8.5H2O ( 1 ) coordination polymer. This compound exhibits humidity-induced variation of the number of water molecules of crystallisation leading to a reversible structural phase transition and the alternation of the long-range ferromagnetic ordering temperature from TC=29 K for the pristine assembly ( 1 ) to TC=49 K for the sample stored in a low-humidity atmosphere ( 1-deh ). This phenomenon can be attributed to a reversible change in the hydrogen-bonding network resulting in the modification of the local geometries of cobalt(II) as well as the cyanido bridges. 相似文献
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136.
Keiko Kokeyama June Gyu Park Kyuman Cho Shin Kirii Tomotada Akutsu Masayuki Nakano Shogo Kambara Kunihiko Hasegawa Naoko Ohishi Kohei Doi Seiji Kawamura 《Physics letters. A》2018,382(29):1950-1955
Recently, a folded Mach–Zehnder interferometer with homodyne in- and quadrature-phase detection was proposed as a high-precision, wide-dynamic range tilt sensor. By way of a practical application and to validate actual performance, two-axis tilt sensors were developed and installed for one mirror of the input mode cleaner cavity in KAGRA, the large-scale cryogenic gravitational-wave telescope in Kamioka, Gifu, Japan. Building on previous work, we have demonstrated that the two-axis tilt sensor has properly sensed the tilt angle changes of the mirror motion with high precision and without calibration. Compared with our initial angular sensor, an optical lever, which is calibrated by using the interferometer tilt sensor, we found that both sensors showed actual tilt motions of the mirror at low frequencies, and the two-axis interferometer sensor has a better sensitivity at higher frequencies. 相似文献
137.
Y Ohishi T Machida K Tashiro S Torii F Yoshigoe H Yamada M Tanno Y Mashima H Toyama H Murata 《Radioisotopes》1990,39(10):431-438
To calculate renal uptake of 99mTc-dimercaptosuccinic acid (DMSA) more accurately using single photon emission computed tomography (SPECT), it is necessary to estimate values of threshold level, which corresponds to the ratio of kidney to background (BG ratio). Thus the phantom and clinical studies were conducted. Six kinds of renal phantoms of 80 to 339 ml, contained different radioactivity of 37 to 485 MBq were prepared. These phantoms were placed in a larger body phantom filled with 1 to 50% of radioactivity representing background. Clinical application of this method was also performed. Results were as follows. 1) A significant correlation between phantom volumes and estimated volumes obtained using threshold level based on BG ratio calculated on tomographic images was found (r = 0.99). 2) A significant correlation between total counts in estimated volumes and radioactivities in phantoms was recognized (r = 0.94). 3) Known radioactivity in phantoms and radioactivity in estimated volumes were highly related (r = 0.98). 4) Clinical application showed valuable results in patients with renal dysfunction. Thus, this method can calculate more accurate renal uptake of 99mTc-DMSA. 相似文献
138.
Na2[Cr(CO)5] (1) was found to be an efficient catalyst for the dimerization of aldehydes to carboxylic esters. Several aromatic aldehydes including furfural gave the corresponding esters in good yields. This reaction also proceeded intramolecularly to give phthalide from phthalaldehyde. Compared with M2[Fe(CO)4] (M = Na, K), 1 was found to be a more efficient catalyst for this reaction. However, aliphatic aldehydes gave aldolcondensation products instead of the corresponding esters. In the reactions of p-substituted benzaldehydes with 1, the reactivity decreased with the increase of the electron-releasing ability of the substituents. However, even p-anisaldehyde, which hardly reacted with M2[Fe(CO)4], reacted with 1 to give the ester in moderate yield. The reaction mechanism, including the nucleophilic attack of the pentacarbonylchromate dianion on the carbonyl carbon, is discussed. 相似文献
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140.
Tsuji E Ando K Kunitomo J Yamashita M Ohta S Kohno S Ohishi Y 《Organic & biomolecular chemistry》2003,1(18):3139-3141
Novel 3-acetoacetylaminobenzo[b]furan derivatives with a modified triene system at the 3-position were prepared through acylation of the 3-aminobenzo[b]furans with 5-methylisoxazole-4-carboxylic acid chloride followed by basic cleavage of the isoxazole ring and several of these compounds showed moderate cysteinyl leukotriene receptor 2 antagonistic activity. 相似文献