A new determination method of interatomic potential for sodium silicate glass simulations

An interatomic potential for the classical molecular dynamics (MD) simulation of sodium silicate glasses was proposed. The ionic charges for this interatomic potential were determined by Mulliken population analysis via the density functional theory (DFT) calculation of alkali silicate crystals. The Si-O interatomic potential energy curve was determined by molecular orbital (MO) calculation of SiO2 +. The results of classical MD simulations using the new interatomic potential were consistent with the experimental trends in interatomic distance, thermal expansion coefficient, molar volume, Si-O-Si bond angle distribution, and Qn ratio with respect to the sodium composition of the silicate glass. The proposed interatomic potential improves the reproducibility of the ring size distribution in silicate glasses compared to conventional potentials

Field-induced carrier delocalization in the strain-induced Mott insulating state of an organic superconductor

We report the influence of the field effect on the dc resistance and Hall coefficient in the strain-induced Mott insulating state of an organic superconductor $\kappa$-(BEDT-TTF)$_{2}$Cu[N(CN)$_{2}$]Br. Conductivity obeys the formula for activated transport $\sigma_{\Box} = \sigma_{0}\exp(-W/k_{B}T)$, where $\sigma_{0}$ is a constant and $W$ depends on the gate voltage. The gate voltage dependence of the Hall coefficient shows that, unlike in conventional FETs, the effective mobility of dense hole carriers ($\sim1.6\times 10^{14}$ cm$^{-2}$) is enhanced by a positive gate voltage. This implies that carrier doping involves delocalization of intrinsic carriers that were initially localized due to electron correlation.Comment: 5 pages, 3 figure

Numerical investigation on sand erosion phenomenon of coated and uncoated vanes in low-pressure gas turbine

For energy saving and less environmental impact, efficient energy utilization is of importance. In a gas-turbine engine, its performance increases as increasing temperature of the turbine inlet flow. However, turbine components are required to be protected from the high temperature flows. Recently, ceramic matrix composite (referred as CMC, hereafter) is expected to be utilized as protecting the gas-turbine components due to the excellent properties of CMC in high temperature conditions: low density, high strength and high rigidity. Therefore, the CMC allows us to increase the inlet temperature and leads to high performance of gas-turbine engines. On the other hand, sand erosion phenomenon is one of serious problems in gas-turbine engines. Sand particles ingested from the engine inlet impinge and erode the wall surfaces, which can cause engine failure. In order to prevent the sand erosion phenomenon, anti-erosion coatings have been developed and adopted for gas-turbines, although the anti-erosion characteristics of the CMC coating have not completely been clarified. The objective of the present paper is to perform numerical simulations of sand erosion phenomenon on the coated and the uncoated T106 CMC vanes in a low-pressure gas turbine. We investigate the flow field, particle trajectories and the eroded shape of the CMC turbine vanes. The results show that the erosion occurs near the leading edge and at the 90 percent axial chord on the pressure surface in both of the coated and uncoated cases. In the uncoated case, the severe erosion phenomenon is observed especially. Accordingly, we have concluded that the coating obviously played an important role in protecting the CMC vanes from sand erosion

Involvement of Fusobacterium Species in Oral Cancer Progression : A Literature Review Including Other Types of Cancer

Chronic inflammation caused by infections has been suggested to be one of the most important cause of cancers. It has recently been shown that there is correlation between intestinal bacteria and cancer development including metastasis. As over 700 bacterial species exist in an oral cavity, it has been concerning that bacterial infection may cause oral cancer. However, the role of bacteria regarding tumorigenesis of oral cancer remains unclear. Several papers have shown that Fusobacterium species deriving the oral cavities, especially, play a crucial role for the development of colorectal and esophageal cancer. F. nucleatum is a well-known oral bacterium involved in formation of typical dental plaque on human teeth and causing periodontal diseases. The greatest characteristic of F. nucleatum is its ability to adhere to various bacteria and host cells. Interestingly, F. nucleatum is frequently detected in oral cancer tissues. Moreover, detection of F. nucleatum is correlated with the clinical stage of oral cancer. Although the detailed mechanism is still unclear, Fusobacterium species have been suggested to be associated with cell adhesion, tumorigenesis, epithelial-to-mesenchymal transition, inflammasomes, cell cycle, etc. in oral cancer. In this review, we introduce the reports focused on the association of Fusobacterium species with cancer development and progression including oral, esophageal, and colon cancers