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11.
Heat capacities of MnxFe3?xO4 with the composition x = 1.0, 1.5, and 2.0 were measured from 200 to 740 K. λ-type heat capacity anomalies due to the ferri-paramagnetic transition were observed for all the compositions. The transition temperatures were 577, 471, and 385 K for the composition x = 1.0, 1.5 and 2.0, respectively, which are in good agreement with the results of magnetic measurements. The difference in heat capacities between the different samples was small except for the temperature range of the transition. The magnetic contribution to the observed heat capacity was obtained by assuming that the heat capacity can be expressed by the sum of the lattice heat capacity Cv (l), the dilation contribution C(d), and the magnetic contribution C(m). Entropy changes due to the transition were obtained from C(m) as 55.5, 50.7 and 49.2 J K?1 mole?1 for the composition x = 1.0, 1.5, and 2.0, respectively. The entropy changes were also calculated by assuming the randomization of unpaired electron spins on each ion, but they were from 6 to 10 J K?1 mole?1 smaller than the observed ones. The difference between the experimental and the calculated values is roughly explained by taking into account the cation exchange reaction between the tetrahedral and the octahedral sites in the spinel structure. 相似文献
12.
We study topological conditions that must be satisfied by a compactC ∞ Levi-flat hypersurface in a two-dimensional complex manifold, as well as related questions about the holonomy of Levi-flat hypersurfaces. As a consequence of our work, we show that no two-dimensional complex manifold admits a subdomain Ω with compact nonemptyC ∞ boundary such that Ω ? ?2. 相似文献
13.
K. Kondo H. Kawabata S. Ueda H. Hasegawa O. Mitamura Y. Seike J. Inaba Y. Ohmomo 《Journal of Radioanalytical and Nuclear Chemistry》2004,260(1):81-87
A nuclear fuel reprocessing facility is currently under construction in Rokkasho Village, Aomori, Japan. After completion
and start-up, this facility will discharge radionuclides into the Pacific Ocean through an outlet pipe set on the seafloor
offshore. For future assessments of the stability of these radionuclides in the environment, a sufficient understanding of
the behavior of radionuclides in this ocean ecosystem before the start-up of the facility is necessary. To understand the
processes by which radionuclides and various other types of elements are eliminated from seawater, we measured the sedimentation
flux of suspended particles in the coastal waters off Rokkasho Village where the sea emissions pipes will be placed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
14.
Atsuhisa Mimoto Sojiro Kon Takuya Motomura Minoru Inaba 《Journal of fluorine chemistry》2005,126(7):1101-1110
The Ni-based alloys, such as Ni-Co, Ni-Mn, Ni-Ag, Ni-Cu, Ni-Al and Ni-Si, prepared by hot isostatic pressing (HIP) at 1000 °C under 2 × 108 Pa for 2 h were employed as the anodes for electrolytic production of NF3. The current efficiencies for NF3 formation were 42-38, 52-40, 52-47, 63-62, 50 and 41% for Ni-Co, Ni-Mn, Ni-Ag, Ni-Cu, Ni-Al and Ni-Si alloys, respectively. The current efficiencies only on Ni-Cu alloys with Cu concentrations lower than 10 mol% were almost the same as those on Ni sheet and HIPed Ni anodes, whereas those on the other alloys used in this study were smaller compared with those on both Ni anodes. On the other hand, the current losses caused by anodic dissolution of Ni-Co, Ni-Mn, Ni-Ag, Ni-Cu, Ni-Al and Ni-Si alloy electrodes were 7.95-4.42, 6.40-7.02, 5.60-6.30, 3.34-6.33, 5.10 and 0.18%, respectively. The anode consumptions of Ni-5 mol% Cu and Ni-5 mol% Si alloys were almost the same or smaller compared with those of Ni sheet and HIPed Ni electrodes, though those of other alloys used were large compared with those of both Ni anodes. Consequently, addition of Cu to the nickel matrix is available for a cheaper cost of anode with keeping a same current efficiency as that on the Ni anode and addition of Si to the nickel matrix is effective for decreasing anode consumption largely. A Ni sheet electrode containing a trace of impurities, such as Co, Mn, Ag and Al, is also favorable as the anode for electrolytic production of NF3. 相似文献
15.
Yoshikata Koga Takemi Kondo Yuji Miyazaki Akira Inaba 《Journal of solution chemistry》2012,41(8):1388-1400
Using the 1-propanol (1P) probing methodology we have developed earlier, we characterized the effects of sulphate and tartrate anions on the molecular organization of H2O. The results indicate that these two large anions belong to a new class of ??hydrophobe-like hydration center??. That is, sulphate and tartrate ions act as ??hydration centers?? with the hydration number 14±3 for both, and leave the bulk H2O, away from hydration shells, unperturbed in the absence of the probing 1-propanol. As the mole fraction of the probe increases, however, the hydrogen bond probability of bulk H2O away from hydration shells appears to decrease smoothly, as occurs with ??hydrophobes?? in H2O. We plot the negative hydration number against the power to reduce the hydrogen bond probability of bulk H2O for the two large anions. We also plotted the characteristic indices for ??hydrophiles?? and ??hydration centers?? whose characteristics we determined in the same manner earlier. H2O defines the origin on this map. We found that a typical Hofmeister ranking for each anion matches reasonably well with that of the distance from the origin for each ion, in decreasing order starting from ions plotted in the north-west quadrant (representing the ??hydrophobe-like?? behavior) of the map and then in increasing order from the origin towards the south on the ordinate, the ??hydrophile-like?? behavior. These findings could be useful in understanding the Hofmeister series, pointing to the importance of the contribution made by the effect of each ion on H2O, in addition to helping understand direct ion-protein interactions. 相似文献
16.
Abstract The polymerizations of alkyl esters of propiolic acid by Rh complex catalysts were investigated. [Rh(norbornadiene)Cl]2, which was the most active among the catalysts examined, gave rise to poly(alkyl propiolate) in a fairly high yield (~80%) in the presence of alcohol as the polymerization solvent. The polymers formed were a pale yellow powder soluble in common organic solvents except for poly(methyl propiolate). The structures of the polymers obtained were investigated by IR, 13C-NMR, CP MAS 13C-NMR, and laser Raman spectroscopies, together with the x-ray diffraction method. Based on these spectroscopic data, it was concluded that this Rh complex can be called a stereoregular polymerization catalyst of alkyl propiolate because the poly(alkyl propiolate) obtained has a cis-transoidal structure. 相似文献
17.
K. Kondo H. Kawabata S. Ueda H. Hasegawa J. Inaba O. Mitamura Y. Seike Y. Ohmomo 《Journal of Radioanalytical and Nuclear Chemistry》2003,257(2):305-312
We investigated the distribution of aquatic plants and the absorption of radionuclides by them in the brackish Lake Obuchi, Japan, which is bordered by nuclear fuel cycle facilities. We studied 5 species of submerged plants: Zannichellia palustris, Ruppia maritima, Potamogeton pectinatus, Zostera japonica, and Z. marina. The plants contained many elements, including radionuclides. The concentrations of 238U, 137Cs, and 90Sr in Z. marina were 11.3-12.4, 0.000-0.144, and 0.151-0.202 Bq.kg-1 dw, respectively. Those in Z. japonica were 5.2-8.8, 0.000-0.267, and 0.081-0.175 Bq.kg-1 dw, respectively. The concentrations of these radionuclides in the plants tended to be higher in higher-salinity regions than in lower-salinity regions of the lake. We found a close relationship between photosynthetic activity and the absorption of stable Sr by plants in the laboratory. Salinity, illumination, and water temperature influenced the photosynthetic activity of the plants and the consequent absorption of elements. 相似文献
18.
An optical sensor using a quartz core microcantilever was fabricated by etching clad layer from optical fiber. The temperature dependence of the resonance frequency of this sensor was measured in atmosphere and water. The temperature coefficient of the resonance frequency in water was 1.3×10−3/°C, which was about one order larger than that (2.3×10−4/°C) in atmosphere. This was caused by increase of additional mass due to temperature dependence of the viscosity of water, while, the increase of the resonance frequency in atmosphere was caused by temperature dependence of Young’s modulus of the quartz core. These results were evaluated theoretically using a “string-of-beads” model. 相似文献
19.
T. Matsuo T. Maekawa A. Inaba O. Yamamuro M. Ohama M. Ichikawa T. Tsuchida 《Journal of Molecular Structure》2006,790(1-3):129
The heat capacities of HCrO2 and DCrO2 have been measured at temperatures between 5 and 360 K. A lambda anomaly occurred at 320 K for DCrO2 but not for HCrO2. Infrared spectra were recorded at temperatures between 5 and 405 K. The spectrum of DCrO2 changed at 320 K with respect to the peak wave-number and splitting of some of the vibrations, while those of HCrO2 depended smoothly on temperature. These experimental results are discussed in terms of a deuteration-induced phase transition. 相似文献
20.
An infrared, pulsed heterodyne laser radar using differential absorption technique with tunable lasers is proposed as a practical means of measuring dispersed air pollutants with range resolution. A system analysis shows that this scheme offers an adequate sensitivity for ranges up to several km. 相似文献