Utsunomiya University

About: Utsunomiya University is a education organization based out in Utsunomiya, Japan. It is known for research contribution in the topics: Laser & Holography. The organization has 4139 authors who have published 6812 publications receiving 91975 citations. The organization is also known as: Utsunomiya daigaku.

Preferential penetration path of gallium into grain boundary in practical aluminium alloy

Abstract: The preferential penetration of a liquid metal along grain boundaries (GBs) in polycrystalline metals is a well-known phenomenon. Gallium-decorated GB networks in rolled aluminium alloys have been visualized three-dimensionally using the high-resolution synchrotron radiation computer tomography (SRCT). The distribution of gallium concentration along GBs was measured using X-ray absorption. Statistical correction for blurring was performed to raise accuracy of the measurement, and then compared with orientation mapping by the SEM/EBSP method on the surface of a tomographic specimen. The pancake-like grain microstructure formed by a rolling process causes the anisotropy of penetration direction. Although the gallium penetrated into high-angle GBs, all of the high-angle GBs are not necessarily decorated by the gallium. The reason for this may be explained by considering geometrically possible penetration paths that seem to be dependent on local grain arrangement and GB structure through each path. The depend...

Bifurcation sets and chaotic states of a gear system subjected to harmonic excitation

Abstract: The gear dynamics is described by a time-varying nonlinear differential equation due to the time dependence of tooth stiffness and backlash. To discuss whether or not distinctive new phenomena occur in the gear system with its backlash and time-variable characters is an important and interesting problem from a practival viewpoint of estimating the dynamic load or gear noise as well as an academic one of contribution to nonlinear mechanics. In this study, the bifurcation sets of periodic solutions under some gear parameters are obtained and chaotically transitional phenomena are investigated by using the Poincare map.

Snapshot multispectral polarization imaging using a photonic crystal filter array

Abstract: A new filter array and a demosaicking method for snapshot multispectral polarization imaging are proposed in this paper. The proposed filter array is a thin-film wavy multilayer structure regarded as a photonic crystal that can be fabricated using the autocloning method. The multispectral polarization filter array is developed by altering the wave structure of the photonic crystal at each pixel. In addition, we propose a demosaicking method for multispectral polarization images by considering snapshot imaging as a linear model. In the experiments, we evaluated the recovered spectrum error in some color charts and showed various demosaicked images such as multispectral polarization images, specific-band degree of linear polarization images, polarized RGB images, and non-polarized RGB images.

Induction of Germination

Abstract: Germination is the first crucial step in the life cycle of obligate root parasitic Orobanchaceae, which cannot survive on their own. Therefore, germination of the tiny seeds with minimal reserves should occur only near host roots. These parasites detect the presence of hosts by using root-derived signalling molecules belonging to several distinct classes of metabolites. Strigolactones, the most important germination stimulants, are derived from carotenoids through the action of carotenoid isomerase, carotenoid cleavage dioxygenases, and possibly a cytochrome P450 enzyme. Strigolactone production is increased under phosphate and nitrogen deficiencies. Strigolactones also attract arbuscular mycorrhizal fungi and act as plant hormones that decrease shoot and increase root branching. Various strigolactones have been identified, and the biological processes have differential sensitivity to different strigolactones. Germination stimulants may be a target for the control of parasitic weeds, but considering their other biological functions, such strategies need to be carefully analyzed for unwanted side effects.