Novel linear algebraic theory and one-hundred-million-atom electronic structure calculation on the K computer

A novel linear-algebraic algorithm, multiple Arnoldi method, was developed in an interdisciplinary study between physics and applied mathematics and realized one-hundred-million-atom (100-nm-scale) electronic state calculations on the K computer. The algorithms are Krylov-subspace solvers for generalized shifted linear equations and were implemented in our order-N calculation code ELSES (http://www.elses.jp/). Moreover, a method for calculating eigen states is presented as a theoretical extension.Comment: 4 pages, 2 figure

High source–sink ratio at and after sink capacity formation promotes green stem disorder in soybean

Green stem disorder (GSD) of soybean is characterized by delayed leaf and stem maturation despite normal pod maturation. Previous studies have suggested that GSD occurrence is promoted by a high source–sink ratio, which is produced by thinning or shade removal at the R5 growth stage (the beginning of seed filling). Here the effects of different times and durations of shade removal after the R5 stage on GSD severity were analyzed. First, shade removal for more than 28 days after R5 increased GSD severity by more than 0.4 point in GSD score. Thinning treatment at R5 increased specific leaf weight by 23%, suppressed stem dry weight reduction, and upregulated 19 genes including those encoding vegetative storage proteins at R5 + 28d, indicating excess source ability relative to sink size. On the contrary, shade removal for 14 days after R5 decreased GSD severity by 0.5 point in GSD score. In this treatment, seed size was smaller, while seed number was significantly larger than control, suggesting that shortage of source ability relative to sink size. These results implied that soybean plants regulate GSD occurrences either positively or negatively according to a source-sink ratio during the R5 to R5 + 28d growth stages

Phosphatidylinositol 4-phosphate 5-kinase β regulates growth cone morphology and Semaphorin 3A-triggered growth cone collapse in mouse dorsal root ganglion neurons

Growth cone motility and morphology, which are critical for axon guidance, are controlled through intracellular events such as actin cytoskeletal reorganization and vesicular trafficking. The membrane phospholipid phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] has been implicated in regulation of these cellular processes in a diverse range of cell types. The main kinases involved in the production of PI(4,5)P2 are the type I phosphatidylinositol 4-phosphate 5-kinase (PIP5K) family, which consist of three isozymes, α, β and γ. Here, we demonstrate the involvement of PIP5Kβ in growth cone dynamics. Overexpression of a lipid kinase-deficient mutant of PIP5Kβ (PIP5Kβ-KD) in mouse dorsal root ganglion (DRG) neurons stimulated axon elongation and increased growth cone size, whereas wild-type PIP5Kβ tended to show opposite effects. Furthermore, PIP5Kβ-KD inhibited growth cone collapse of DRG neurons induced by semaphorin 3A (Sema3A). These results provide evidence that PIP5Kβ negatively regulates axon elongation and growth cone size and is involved in the cellular signaling pathway for Sema3A-triggered repulsion in DRG neurons

Polarization-induced photovoltaic effects in Nd-doped BiFeO 3 ferroelectric thin films

BiFeO 3 (BNF) thin films were fabricated on SrRuO 3 (SRO)-coated (100) Nb-doped SrTiO 3 subtrates by pulsed laser deposition, and nondoped BiFeO 3 (BFO) thin films were also fabricated similarly for comparison. Then, Nd-doping effects on ferroelectric and photovoltaic properties were evaluated. Polarization-induced photovoltaic effects were observed in both the BFO and BNF solar cell structures with top and bottom electrodes under intense laser illumination. Using Au top electrodes, enhanced photovoltaic properties were observed in the BNF cell compared with the BFO cell. To improve the photovoltaic properties of the BNF cell, instead of the Au top electrodes, In-Sn-O (ITO) top electrodes were employed for the BNF cell. As a result, the photovoltaic properties were found to be markedly improved, resulting in an open circuit voltage of 0.81 V and a short circuit current density of 12.1 mA/cm2. © 2012 The Japan Society of Applied Physics

Graphical Evaluation Method for Void Distribution in Direct Energy Deposition

AbstractDirect energy deposition (DED) process attracts attention from industries because of its applicability to production of complex shape parts. However, technical challenges still remain in DED, such as void evolution inside of the produced object. This paper provides a new graphical evaluation method of void distribution. Binarizing a cross-sectional image of the cladded object and applying a 2-dimensional Gaussian window, the void distribution rate is separately evaluated in each local area on the cross section. To clarify the relation between void evolution and deposition condition in Inconel 625, the void distribution is experimentally evaluated through the various tests