Tohoku University

About: Tohoku University is a education organization based out in Sendai, Japan. It is known for research contribution in the topics: Magnetization & Alloy. The organization has 72116 authors who have published 170791 publications receiving 3941714 citations. The organization is also known as: Tōhoku daigaku.

Efficient alkaline hydrogen evolution on atomically dispersed Ni–Nx Species anchored porous carbon with embedded Ni nanoparticles by accelerating water dissociation kinetics

Abstract: Developing inexpensive and efficient electrocatalysts for hydrogen evolution reaction (HER) during alkaline water electrolysis is crucial for renewable and sustainable energy harvesting. Herein, we report a novel hybrid electrocatalyst comprising atomically dispersed Ni–Nx species anchored porous carbon (Ni–N–C) matrix with embedded Ni nanoparticles for HER. This new catalyst is synthesized via pyrolysis of hydrothermally prepared supermolecular composite of dicyandiamide and Ni ions followed by an acid etching treatment. The achieved hybrid exhibits superior catalytic performance toward HER with a small overpotential of 147 mV at 10 mA cm−2 and a low Tafel slope of 114 mV dec−1, comparable to those of state-of-the-art heteroatom-doped nanocarbon catalysts and even outperforming other reported transition-metal-based compounds in basic media. Experimental observations and theoretical calculations reveal that the presence of Ni nanoparticles can optimize surface states of Ni−Nx active centers and reduce energy barriers of dissociated water molecules, which synergistically improve OH− adsorption and promote HER kinetics. When served as electrodes for both cathode and anode, an alkaline water electrolyzer could afford a current density of 10 mA cm−2 at a low cell voltage of 1.58 V, rivalling the sufficiently high overpotentials of integrated Pt/C–Ir/C benchmark electrodes.

Ion-beam irradiation, gene identification, and marker-assisted breeding in the development of low-cadmium rice

Abstract: Rice (Oryza sativa L.) grain is a major dietary source of cadmium (Cd), which is toxic to humans, but no practical technique exists to substantially reduce Cd contamination. Carbon ion-beam irradiation produced three rice mutants with <0.05 mg Cd⋅kg(-1) in the grain compared with a mean of 1.73 mg Cd⋅kg(-1) in the parent, Koshihikari. We identified the gene responsible for reduced Cd uptake and developed a strategy for marker-assisted selection of low-Cd cultivars. Sequence analysis revealed that these mutants have different mutations of the same gene (OsNRAMP5), which encodes a natural resistance-associated macrophage protein. Functional analysis revealed that the defective transporter protein encoded by the mutant osnramp5 greatly decreases Cd uptake by roots, resulting in decreased Cd in the straw and grain. In addition, we developed DNA markers to facilitate marker-assisted selection of cultivars carrying osnramp5. When grown in Cd-contaminated paddy fields, the mutants have nearly undetectable Cd in their grains and exhibit no agriculturally or economically adverse traits. Because mutants produced by ion-beam radiation are not transgenic plants, they are likely to be accepted by consumers and thus represent a practical choice for rice production worldwide.

New magic number, N = 16, near the neutron drip line

Abstract: We have surveyed the neutron separation energies $({S}_{n})$ and the interaction cross sections $({\ensuremath{\sigma}}_{I})$ for the neutron-rich $p\ensuremath{-}\mathrm{sd}$ and the $\mathrm{sd}$ shell region. Very recently, both measurements reached up to the neutron drip line, or close to the drip line, for nuclei of $Z\ensuremath{\le}8$. A neutron-number dependence of ${S}_{n}$ shows clear breaks at $N\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}16$ near the neutron drip line $({T}_{Z}\ensuremath{\ge}3)$, which shows the creation of a new magic number. A neutron-number dependence of ${\ensuremath{\sigma}}_{I}$ shows a large increase of ${\ensuremath{\sigma}}_{I}$ for $N\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}15$, which supports the new magic number. The origin of the new magic number is also discussed.

The International Linear Collider Technical Design Report - Volume 1: Executive Summary

Abstract: The International Linear Collider Technical Design Report (TDR) describes in four volumes the physics case and the design of a 500 GeV centre-of-mass energy linear electron-positron collider based on superconducting radio-frequency technology using Niobium cavities as the accelerating structures. The accelerator can be extended to 1 TeV and also run as a Higgs factory at around 250 GeV and on the Z0 pole. A comprehensive value estimate of the accelerator is give, together with associated uncertainties. It is shown that no significant technical issues remain to be solved. Once a site is selected and the necessary site-dependent engineering is carried out, construction can begin immediately. The TDR also gives baseline documentation for two high-performance detectors that can share the ILC luminosity by being moved into and out of the beam line in a "push-pull" configuration. These detectors, ILD and SiD, are described in detail. They form the basis for a world-class experimental programme that promises to increase significantly our understanding of the fundamental processes that govern the evolution of the Universe.