ペータ・ワイルの定理の格子ゲージ理論への応用

本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものである京都大学0048新制・課程博士博士(理学)甲第5306号理博第1480号新制||理||821(附属図書館)UT51-93-F63京都大学大学院理学研究科数理解折専攻(主査)教授 中西 襄, 教授 柏原 正樹, 教授 荒木 不二洋学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDFA

Strain Age Hardening of Aluminium Alloys

The strain age hardening of Al-Cu, Al-Mg and Al-Si alloys was studied and the results obtained were as follows : (1) The characteristics of hardening are generally similar to those of carbon steels, copper alloys and austenitic steels, although its degree is appreciably low. (2) In Al-4.9 per cent Cu alloy solution-treated and aged, the strain age hardening and the inelastic effect are less marked in a fully age-hardened state than in an over-aged state, the difference being probably due to the circumstances that dislocations pass through GP zones, whereas the θ\u27 and θ phases act as an effective barrier against dislocation movement, pile-ups of dislocation being formed in a large number. (3) The hardening is generally marked in such an alloy as exhibiting high degrees of work hardening rate and X-ray line broadening, these being relatively low in aluminium alloys. The effect of alloying on the strain age hardening seems to form strong barriers against the movement of dislocations and a high density of piled-up dislocations during cold working rather than to take short range ordering or to segregate into stacking faults during low temperature annealing

Strain Age Hardening of Austenitic Ni-Cr Steel

The strain age hardening of austenitic Ni-Cr steels was studied, the chief purpose being to compare the characteristics between the one-phase structure in which austenite is stable and the two-phase one containing martensite. The results obtained were as follows : (1) The increase in hardness occurred in two stages on annealing below 450℃ after severe cold-working, the difference in the characteristics of the one-phase and the two-phase steels not being detected except that in the latter the hardening is very marked from the beginning with the progress of cold working. (2) The hardening was considered to concern mostly a dislocation-dislocation interaction. (3) The characteristics of the hardening are exactly similar to those of carbon steels in the range 150～350℃ and copper alloys

Corrosion and Erosion of Ferritic Steel by Liquid Bismuth

Static corrosion of Fe-C-Cr alloys and erosion of Fe-C and Fe-Cr alloys due to the contact with liquid bismuth were studied. For the static corrosion test, magnesium as a deoxidant and zirconium as an inhibitant were added into liquid bismuth prior to the immersion of specimens. The erosion test was carried out by applying an ultrasonic oscillation of 20±2 kc in frequency and 15 microns in amplitude. The results obtained were as follows. (1) In Fe-C alloys, when the carbon content increases the degree of static, corrosion becomes less. In Fe-C-Cr alloys, the chromium content enhances the degree of static corrosion. For the inhibition of corrosion the increase of carbon content in the alloy may be necessary. (2) From the erosion test it was found that the surface pits are not due to a chemical corrosion but to a mechanical attack, and that the degree of erosion chiefly depends on the hardness of the alloy

Corrosion of Chromium Steel by Liquid Bismuth

The static corrosion of chromium steel by immersing in liquid bismuth at 600～950℃ was studied, and the results obtained are as follows : (1) The corrosion loss increases with increasing chromium content. With the addition of zirconium as an inhibitor to liquid bismuth, the corrosion loss of high chromium steels becomes very slight, provided the carbon content is sufficiently high. (2) The growth of ZrC film at the steel surface is retarded by increasing the amount of chromium in steel. Thus, chromium steel is more favorable than carbon steel for a container of liquid bismuth

Fe-K line probing of material around the AGN central engine with Suzaku

We systematically analyzed the high-quality Suzaku data of 88 Seyfert galaxies. We obtained a clear relation between the absorption column density and the equivalent width of the 6.4 keV line above 10$^{23}$ cm$^{-2}$, suggesting a wide-ranging column density of $10^{23-24.5}$ cm$^{-2}$ with a similar solid and a Fe abundance of 0.7--1.3 solar for Seyfert 2 galaxies. The EW of the 6.4 keV line for Seyfert 1 galaxies are typically 40--120 eV, suggesting the existence of Compton-thick matter like the torus with a column density of $>10^{23}$ cm$^{-2}$ and a solid angle of $(0.15-0.4)*4pi$, and no difference of neutral matter is visible between Seyfert 1 and 2 galaxies. An absorber with a lower column density of $10^{21-23}$ cm$^{-2}$ for Compton-thin Seyfert 2 galaxies is suggested to be not a torus but an interstellar medium. These constraints can be understood by the fact that the 6.4 keV line intensity ratio against the 10--50 keV flux is almost identical within a range of 2--3 in many Seyfert galaxies. Interestingly, objects exist with a low EW, 10--30 eV, of the 6.4 keV line, suggesting that those torus subtends only a small solid angle of $<0.2*4pi$. Ionized Fe-K$\alpha$ emission or absorption lines are detected from several percents of AGNs. Considering the ionization state and equivalent width, emitters and absorbers of ionized Fe-K lines can be explained by the same origin, and highly ionized matter is located at the broad line region. The rapid increase in EW of the ionized Fe-K emission lines at $N_{H}>10^{23}$ cm$^{-2}$ is found, like that of the cold material. It is found that these features seem to change for brighter objects with more than several $10^{44}$ erg/s such that the Fe-K line features become weak. We discuss this feature, together with the torus structure.Comment: 32 pages, 20 figures, ApJ accepte

Radiation dosimetry in digital breast tomosynthesis: Report of AAPM Tomosynthesis Subcommittee Task Group 223

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134828/1/mp2600.pd

Extreme deformability of insect cell membranes is governed by phospholipid scrambling

昆虫の細胞は柔らかい！ --細胞膜を柔らかくするタンパク質を発見--. 京都大学プレスリリース. 2021-06-09.Organization of dynamic cellular structure is crucial for a variety of cellular functions. In this study, we report that Drosophila and Aedes have highly elastic cell membranes with extremely low membrane tension and high resistance to mechanical stress. In contrast to other eukaryotic cells, phospholipids are symmetrically distributed between the bilayer leaflets of the insect plasma membrane, where phospholipid scramblase (XKR) that disrupts the lipid asymmetry is constitutively active. We also demonstrate that XKR-facilitated phospholipid scrambling promotes the deformability of cell membranes by regulating both actin cortex dynamics and mechanical properties of the phospholipid bilayer. Moreover, XKR-mediated construction of elastic cell membranes is essential for hemocyte circulation in the Drosophila cardiovascular system. Deformation of mammalian cells is also enhanced by the expression of Aedes XKR, and thus phospholipid scrambling may contribute to formation of highly deformable cell membranes in a variety of living eukaryotic cells