4,508 research outputs found
Quantum critical phenomena of unconventional superconductors: U(1) gauge model of link Cooper pair
In this paper we shall study quantum critical behavior of lattice model of
unconventional superconductors (SC) that was proposed in the previous papers.
In this model, the Cooper-pair (CP) field is defined on lattice links in order
to describe d-wave SC. The CP field can be regarded as a U(1) lattice gauge
field, and the SC phase transition takes place as a result of the phase
coherence of the CP field. Effects of the long-range Coulomb interactions
between the CP's and fluctuations of the electromagnetic field are taken into
account. We investigate the phase structure of the model and the critical
behavior by means of the Monte Carlo simulations. We find that the parameter,
which controls the fluxes (vortices) of the CP, strongly influences the phase
structure. In three-dimensional case, the model has rich phase structure. In
particular there is a "monopole proliferation" phase transition besides the SC
phase transition. Depending on the parameters, this transition exists within
the SC phase or takes place simultaneously with the SC transition. This new
type of transition is relevant for unconventional SC's with strong spatial
three-dimensionality and to be observed by experiments.Comment: 13pages,25figure
The Growth of Grey Cast Iron : Second Report
The influence of ammonia, methane and water vapour mixed with nitrogen _or hydrogen upon the growth of grey cast iron was confirmed by the same method as adopted in the previous investigation. The graphitization of the pearlite-cementite in grey cast iron was also measured by dilatometer in various atmospheric conditions. Examining the results, it was confirmed that the abnormal expansion at Ar transformation of grey cast iron is due to the graphitization of the pearlite-cementite as presumed by Benedicks and Löfquist
Chromatin Evolution and Molecular Drive in Speciation
Are there biological generalities that underlie hybrid sterility or inviability? Recently, around a dozen “speciation genes” have been identified mainly in Drosophila, and the biological functions of these genes are revealing molecular generalities. Major cases of hybrid sterility and inviability seem to result from chromatin evolution and molecular drive in speciation. Repetitive satellite DNAs within heterochromatin, especially at centromeres, evolve rapidly through molecular drive mechanisms (both meiotic and centromeric). Chromatin-binding proteins, therefore, must also evolve rapidly to maintain binding capability. As a result, chromatin binding proteins may not be able to interact with chromosomes from another species in a hybrid, causing hybrid sterility and inviability
Influence of Various Gases upon Graphitization in Cast Iron
(1) From the results of the present investigation; it is concluded that so called “U mgekehrter Hartguss” is produced under the action of the gases contained in it. (2) The formation of the fine graitwd fracture in pig iron is probably due in some cases to the influence of the hydrogen absorbed in molten cast iron
嗅球からのαシヌクレイン伝播による霊長類レヴィ小体病モデル
京都大学新制・論文博士博士(医学)乙第13525号論医博第2271号新制||医||1062(附属図書館)京都大学大学院医学研究科医学専攻(主査)教授 井上 治久, 教授 大森 孝一, 教授 古川 壽亮学位規則第4条第2項該当Doctor of Medical ScienceKyoto UniversityDFA
The Growth of Grey Cast Iron : Third Report
The present investigation was carried out to make clear the relation between the growth of grey cast iron due to the abnormal expansion at Ar transformation and that due to oxidation. The various kinds of dilatometer were used for this purpose. According to the author's results, when grey cast iron is repeatedly heated at a high temperature in air, growth takes place principally due to oxidation and growth of this kind is much larger than that due to the abnormal expansion at Ar transformation. It is acceptable that grey cast iron becomes susceptible to oxidation by passing through its Ar critical range, hence its growth is accelerated by oxidation. But the author cannot agree with the investigations who believe that the abnormal expansion at Ar transformation is a direct cause of growth in every case, the effect of oxidation being indirect
On the Structure of the Steel Carburized by Various Hydrocarbons
Under the probable assumption that one of the chief causes for the formation of the abnormal structure in carburized steel exits in O₂ contained in steel in large quantity, the author carried out some experiments to prevent the formation of the structure in question. As the specimens, Armco iron was first adopted which was determined by analysis to have 0.0₆₇ per cent of 0₂. It was found that the abnormal structure was scarcely developed in the specimens which were carburized in some gaseous hydrocarbons such as CH₄ , C₂H₄ or C₂H₂ and in CO containing the vapour of liquid hydrocarbons such as C₆H₆, C₇H₈, C₅H₁₂, C₆H₁₄, C₇H₁₆ or C₈H₁₈ in spite of its prevailing in those carburized by some commercial solid carburizers _and in the mixture of charcoal and 40 per cent. of BaC0₃. These phenomena can be easily understood if the assumption before mentioned is, true, because hydrocarbons deoxidize and carburize steel simultaneously at high temperatures. The 3 kinds of other commercial steel were then carburized with C₂H ₂ and CO containing C₆H₅ or C₅H₁₂ which were found to be very effective for the improvement of the structure of carburized steel in the preceeding experiments. A similar effect from these carburizers, however, was not observed in this case, notwithstanding the fact that the oxygen content of these steel specimens is less than or almost equal to that of Armco iron. This is doubtless due to the fact that the cause for the formation of the abnormal structure in carburized steel is not so simple as before assumed
CHARACTERlSTlCS OF BODY MOTION IN A NOVICE RACE WALKER
The purpose of this study was to clarify the movement characteristics of novice race walkers using kinematics analysis. A junior high school newcomer 5km race was videotaped at 60 field/s with a video camera. The subjects were 16 junior high school student race walkers. The results were summarized as follows, (IT)h e stance phase of the novice race walkers was longer than that of experienced walkers referred to several previous studies. (2) There was a significant relationship between the walking speed and the step length in experienced walkers and faster novice walkers. However, the group of slower walkers in this study had a small stride length, and there was no significant relationship between the walking speed and the step length
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