著者

Kinoshita Chiken Nakai Kiyomichi Fukumoto Ken-ichi Kutsuwada Masanori Nogita Kazuhiro

出版者

Tohoku University

雑誌

Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy (ISSN:00408808)

巻号頁・発行日

vol.35, no.2, pp.417-425, 1991-03-05

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The cascade damage and its kinetic behavior in various kinds of ceramics irradiated with fission- and fusion-neutrons have been examined through transmission electron microscopy. Fission- and fusion-neutrons introduce relatively dilute concentration of point defects around primary knock-on atoms through the displacement cascade process in low-Z ceramics. Higher concentration of point defects, which induces the contrast corresponding to the cascade damage though TEM, is induced only in covalent crystals consisting of relatively high-Z elements. The nucleation and growth process of interstitialloops is strongly affected by the crystal structure and structural vacancy.

著者

Inoue Akihisa Masumoto Tsuyoshi

出版者

Tohoku University

雑誌

Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy (ISSN:00408808)

巻号頁・発行日

vol.29, pp.305-330, 1980

著者

SUZUKI Nubo AKIBA Kenichi

出版者

東北大学

雑誌

Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy (ISSN:00408808)

巻号頁・発行日

vol.23, 1971

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The distribution ratios of a typical chelate of divalent metal ion, Be^<2+>, with TTA, between an aqueous perchlorate solutions (μ=0.1) and nearly 40 organic solvents including inert, ether, ester, ketone, and alcohol solvents were determined as a function of pA at 25℃. The extractable chelate was identified to be BeA_2 and no adduct formation with excess of uncomplexed free TTA or oxygen-containing solvent itself was observed. The distribution coefficient of the chelate (P_M) was compared with that of TTA (P_<HA>) and it is found that the relationship expressed by the following formula holds good in the present system also, log P_M =n log P_<HA>+const. Accordingly, the distribution of the same chelate into another solvent or the distribution of the stimilar type of chelate into an organic solvent can be predicted.

著者

Kingo SUDO Akiichi KIGOSHI

出版者

Tohoku University

雑誌

東北大学研究所報告. A集, 物理学・化学・冶金学 = Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy (ISSN:00408808)

巻号頁・発行日

no.13, pp.31-38, 1961

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Oxidation and reduction equilibria of the composition range of UO_2-U_3O_8 were measured with a flow method at 360~580℃ and the results are summarized as follows : In the composition range of UO_2-U_4O_9 there are two regions : homogeneous region in which oxygen dissolves in UO_2, and heterogeneous region containing UO_2 saturated with oxygen and U_4O_9. The former was found to exist also at lower temperature as Willardson et al. had suggested. In this region Henry's law can be adapted between oxygen potential and solubility of oxygen in solid. The temperature dependence of equilibrium constant is as follows : O[UO_2]=1/2O_2(g), logK=-10, 387/T+19.95logT+0.0391T-86.31. The empirical formula expressing the solubility limit of oxygen in UO_2 phase is given as a function of temperature, [O]= 0.11176 ・ 10^<-4>T^2-1.9465・10^<-2>T+8.479, and the temperature dependence of oxygen potential is given by the following equation 2U_4O_9=8UO_2 (saturated with O)+O_2, logPo_2=-26, 814/ T+19.51 logT+0.02151T-61.18. The composition range of U_4O_9-U_3O_8 can be regarded as a homogeneous solid solution. By using the activities of U_3O_8 and U_4O_9 in solid phase, the temperature function of equilibrium constant is calculated as follows : 8/5U_3O_8 (in solid solution)=6/5U_4O_9 (in solid solution)+O_2, logK=-12, 581/T-6.592logT+0.0627T-35.69. Furthermore, an equilibrium diagram of the uranium oxide-oxygen system was given in this temperature range.

著者

SUZUKI Hideji

出版者

東北大学

雑誌

Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy (ISSN:00408808)

巻号頁・発行日

vol.4, pp.455-463, 1952

被引用文献数

5

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A mechanism of interaction between a dislocation and solute atoms was discussed. It was shown to be reasonable to account for the difference in mechanical behaviours between face-centred and body-centred cubic crystals from the different locking mechanisms between these two types of crystals, the former being locked by a weaker but wider interaction range. while the latter being captured in a stronger and narrower valley of potential energy, the so-called Cottrell's atomosphere. The former results in a low critical shear stress which is almost independent of temperature and rate of strain. The latter gives rise to a very high critical shear stress at low temperatures, which, however, rapidly decreases with the rise of temperature.

著者

Mizuseki H. Tanaka K. Ohno K. Kawazoe Y.

出版者

東北大学

雑誌

Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy (ISSN:00408808)

巻号頁・発行日

vol.43, no.1, pp.55-59, 1997-03-20

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A new Monte Carlo model is introduced to describe the Diffusion-Limited Aggregation (DLA) with extra forces arising from the Lorentz's and/or Coulomb forces. Specific patterns grown under the external force are produced by Monte Carlo simulation. In the present model, the basic movement of particles is the random walk, with different transition probabilities in different directions, which characterize stochastically the effect of the extra forces. In some cases, pattern-formations which are qualitatively different from the standard DLA model are observed and they are compared with preexisting experiments.fractal dimensionDiffusion-Limited Aggregation (DLA)magnetic fieldcrystal growthcomputer simulationrandom walkMonte Carlo method

著者

Furuya H. Idemitsu K. Inagaki Y. Arima T. Sasaki T. Kuroda Y. Uchikawa S. Mitsugashira S. Suzuki Y.

出版者

東北大学

雑誌

Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy (ISSN:00408808)

巻号頁・発行日

vol.45, no.1, pp.89-91, 1997-03-28

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It is necessary to obtain the data of some parameters concerning migration behavior of radionuclides in underground water for the safety assessment of radioactive waste disposal. Sorption and desorption experiments were carried out by using tracer amount of plutonium on biotite in a granitic rock. In this study, pH dependence of distribution coefficients of plutonium on a biotite mineral were measured. The following results are obtained; (1) The biotite has the pH buffer capacity at around pH 5. (2) Plutonium sorption rate was fast around pH 6 but slow at lower pH than 5. (3) The 95 percent of plutonium was sorbed on biotite at around pH 5. (4) The 10 to 30 percent of sorbed plutonium in biotite was desorbed with 1N KCl, the 50 to 60 percent with 1N HN0_3. (5) The rest of plutonium sorbed in biotite could not be desorbed even with 1N HN0_3. (6) The neutral plutonyl hydroxide could be an important species sorbed on the biotite.sorptionplutoniumbiotite

著者

Hosoya M. KAKITA Yachiyo GOTO Hidehiro

出版者

東北大学

雑誌

Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy (ISSN:00408808)

巻号頁・発行日

vol.13, pp.206-214, 1961

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Fundamental experiments were carried out to determine the micro-amounts of aluminium by spectrophotometry, using chrome azurol S, a reagent used in complexometric titration of copper, zirconium and aluminium. By this new method, most part of the iron content was separated by methyl isobutyl ketone, and the remaining iron and copper was masked by thioglycolic acid and after adjusting the pH to 5.6-6.8, the absorbance of the aluminium chelate compound was measured at 550 mμ. This method requires only a few reagents and does not need warming for promoting coloration, nor does it require the protecting colloid in contrast with the aluminon method. Since this reagent presents very sensitive color reaction even in micro-amounts of aluminium, 0.002 to 0.1 per cent of it can be determined with good reproducibility.