Investigation of Microstructure of Cementitious Materials Exposed to High Temperature by Non-destructive Integrated CT-XRD Method

Severe accident occurred in 2011 at the Fukushima Daiichi nuclear power plant and it can be assumed that the concrete building was exposed to high temperatures environment for a long time due to loss of the cooling function of the nuclear reactor. In order to prepare for the best scenario in the decommission plan, it should be first needed to clarify and evaluate the level of damage and deterioration of the contaminated concrete. To solve this problem, experiments were conducted for cementitious materials with the maximum temperature of 400 or 1000 degrees Celsius with durations of up to 2 hours. Subsequent results were evaluated microscopically. In this research, authors have employed a Non-Destructive Integrated CT-XRD Method using synchrotron white X-ray. The unique feature of this method is that both CT for measuring internal structure and XRD for identifying crystal structure can be performed on the same specimen at the same time. Therefore, in addition to other measurements such as the Thin film X-ray diffraction technique, the application of this method is expected to bring an interesting exploration with regard to the physical and chemical alteration of the concrete that was endured by high temperatures

Mitochondrial haplogroups associated with elite Japanese athlete status

Purpose It has been hypothesised that certain mitochondrial haplogroups, which are defined by the presence of a characteristic cluster of tightly linked mitochondrial DNA polymorphisms, would be associated with elite Japanese athlete status. To examine this hypothesis, the frequencies of mitochondrial haplogroups found in elite Japanese athletes were compared with those in the general Japanese population. Methods Subjects comprised 139 Olympic athletes (79 endurance/middle-power athletes (EMA), 60 sprint/power athletes (SPA)) and 672 controls (CON). Two mitochondrial DNA fragments containing the hypervariable sequence I (m16024-m16383) of the major non-coding region and the polymorphic site at m. 5178C>A within the NADH dehydrogenase subunit 2 gene were sequenced, and subjects were classified into 12 major mitochondrial haplogroups (ie, F, B, A, N9a, N9b, M7a, M7b, M*, G2, G1, D5 or D4). The mitochondrial haplogroup frequency differences among EMA, SPA and CON were then examined. Results EMA showed an excess of haplogroup G1 (OR 2.52, 95% CI 1.05 to 6.02, p=0.032), with 8.9% compared with 3.7% in CON, whereas SPA displayed a greater proportion of haplogroup F (OR 2.79, 95% CI 1.28 to 6.07, p=0.007), with 15.0% compared with 6.0% in CON. Conclusions The results suggest that mitochondrial haplogroups G1 and F are associated with elite EMA and SPA status in Japanese athletes, respectivel

Intergrowth and thermoelectric properties in the Bi-Ca-Co-O system

Single crystals of the Bi-Ca-Co-O system have been grown using the flux method with cooling from 900\celsius and 950\celsius, respectively. The single crystals are characterized by transmission electron microscopy and X-ray diffraction. The misfit cobaltite [Ca$_2$Bi$_{1.4}$Co$_{0.6}$O$_4$]$^{RS}$[CoO$_2$]$_{1.69}$ single crystals with quadruple ($n$=4) rocksalt (RS) layer are achieved with cooling from 900\celsius. Such crystal exhibits room-temperature thermoelectric power (TEP) of 180$\mu$V/K, much larger than that in Sr-based misfit cobaltites with quadruple RS layer. However, intergrowth of single crystals of quadruple ($n$=4) and triple ($n$=3) RS-type layer-based misfit cobaltites is observed with cooling from 950\celsius. Both of TEP and resistivity were obviously enhanced by the intergrowth compared to [Ca$_2$Bi$_{1.4}$Co$_{0.6}$O$_4$]$^{RS}$[CoO$_2$]$_{1.69}$ single crystal, while the power factor at room temperature remains unchanged.Comment: 8 pages, 7 figures. To be published in Journal of Crystal Growt

Convexified Gauss curvature flow of bounded open sets in an anisotropic external field a stochastic apporoximation and PDE

We construct a random crystalline ( or polyhedral) approximation of a convexified Gauss curvature flow of bounded open sets in an anisotropic external field. We also show that a weak solution to the PDE which describes the motion of a bounded open set is unique and is a viscosity solution of it

Infrared study of spin crossover Fe-picolylamine complex

Infrared (IR) absorption spectroscopy has been used to probe the evolution of microscopic vibrational states upon the temperature- and photo-induced spin crossovers in [Fe(2-picolylamine)3]Cl2EtOH (Fe-pic). To overcome the small sizes and the strong IR absorption of the crystal samples used, an IR synchrotron radiation source and an IR microscope have been used. The obtained IR spectra of Fe-pic show large changes between high-spin and low-spin states for both the temperature- and the photo- induced spin crossovers. Although the spectra in the temperature- and photo-induced high-spin states are relatively similar to each other, they show distinct differences below 750 cm-1. This demonstrates that the photo-induced high-spin state involves microscopically different characters from those of the temperature-induced high-spin state. The results are discussed in terms of local pressure and structural deformations within the picolylamine ligands, and in terms of their possible relevance to the development of macroscopic photo-induced phase in Fe-pic.Comment: 6 pages (text) and 6 figures,submitted to J. Phys. Soc. Jp

Motion of a graph by R-curvature

We shmv the existence of ,veak solutions to the PDE which de­scribes the motion by R-curvaturc in Rd , by the continuum limit of a class of infinite particle systems. We also show that weak solutions of the PDE arc viscosity solutions and give the uniqueness result on both weak and viscosity solutions

A two dimensional random crystalline algorithm for Gauss curvature flow

In this paper we propose a two dimensional random crystalline algorithm for Gauss cur­vature flow

Poissonian asymptotics of a randomly perturbed dynamical system Flip$B!>(Bflop of the Stochastic Disk Dynamo

A dynamical system with two stable equilibrium points will show a flip-flop motion between the neighborhoods of the two points when it is perturbed by small random noises. A typical example is the stochastic disk dynamo model where the two equilibrium points correspond to the two polarities of the earth's magnetic field. We will prove what has been suggested by a computer simulation, that is, the counting process of the flips or the reversals of the earth's field converges to a standard Poisson process if the time is suitably scaled