868 research outputs found
食品加工廃棄物から効果的なアンモニア生産のための酵母の合成生物学的育種
京都大学新制・課程博士博士(農学)甲第23237号農博第2444号新制||農||1083(附属図書館)学位論文||R3||N5327京都大学大学院農学研究科応用生命科学専攻(主査)教授 植田 充美, 教授 小川 順, 教授 栗原 達夫学位規則第4条第1項該当Doctor of Agricultural ScienceKyoto UniversityDFA
Magnetic Structure of Umbral Dots Observed with Hinode Solar Optical Telescope
High resolution and seeing-free spectroscopic observation of a decaying
sunspot was done with the Solar Optical Telescope aboard Hinode satellite. The
target was NOAA 10944 located in the west side of the solar surface from March
2 to March 4, 2007. The umbra included many umbral dots (UDs) with size of ~300
km in continuum light. We report the magnetic structures and Doppler velocity
fields around UDs, based on the Milne-Eddington inversion of the two iron
absorption lines at 6302 angstrom.
The histograms of magnetic field strength(B), inclination angle(i), and
Doppler velocity(v) of UDs showed a center-to-limb variation. Observed at disk
center, UDs had (1)slightly smaller field strength (Delta B=-17 Gauss) and
(2)relative blue shifts (Delta v=28 m s-1) compared to their surroundings. When
the sunspot got close to the limb, UDs and their surroundings showed almost no
difference in the magnetic and Doppler values. This center-to-limb variation
can be understood by the formation height difference in a cusp-shaped
magnetized atmosphere around UDs, due to the weakly magnetized hot gas
intrusion. In addition, some UDs showed oscillatory light curves with multiple
peaks around 10 min, which may indicate the presence of the oscillatory
convection. We discuss our results in the frameworks of two theoretical models,
the monolithic model (Schussler & Vogler 2006) and the field-free intrusion
model (Spruit & Scharmer 2006).Comment: 8 pages, 8 figures, accepted for publication in PAS
Sustainable Biological Ammonia Production towards a Carbon-Free Society
脱炭素・次世代エネルギーとしてのアンモニアの食品加工廃棄物からのバイオ生産プラットフォーム --脱炭素社会構築へのバイオテクノロジーによる貢献をめざして--. 京都大学プレスリリース. 2021-09-06.A sustainable society was proposed more than 50 years ago. However, it is yet to be realised. For example, the production of ammonia, an important chemical widely used in the agriculture, steel, chemical, textile, and pharmaceutical industries, still depends on fossil fuels. Recently, biological approaches to achieve sustainable ammonia production have been gaining attention. Moreover, unlike chemical methods, biological approaches have a lesser environmental impact because ammonia can be produced under mild conditions of normal temperature and pressure. Therefore, in previous studies, nitrogen fixation by nitrogenase, including enzymatic ammonia production using food waste, has been attempted. Additionally, the production of crops using nitrogen-fixing bacteria has been implemented in the industry as one of the most promising approaches to achieving a sustainable ammonia economy. Thus, in this review, we described previous studies on biological ammonia production and showed the prospects for realising a sustainable society
Static magnetic moments revealed by muon spin relaxation and thermodynamic measurements in quantum spin ice YbTiO
We present muon spin relaxation (SR) and specific-heat versus
temperature measurements on polycrystalline and single-crystal samples
of the pyrochlore magnet YbTiO. exhibits a sharp peak at a
of 0.21 and 0.26~K for the single-crystal and polycrystalline
samples respectively. For both samples, the magnetic entropy released between
50~mK and 30~K amounts to per Yb. At temperatures below
we observe a steep drop in the asymmetry of the zero-field SR time spectra
at short time scales, as well as a decoupling of the muon spins from the
internal field in longitudinal magnetic fields of ~T for both the
polycrystalline and single-crystal samples. These muon data are indicative of
static magnetic moments. Our results are consistent with the onset of
long-range magnetic order in both forms of YbTiO.Comment: 6 pages, 4 figures, accepted to PR
Magnetic order in pyrochlore iridate NdIrO probed by muon spin relaxation
Muon-spin relaxation results on the pyrochlore iridate NdIrO are
reported. Spontaneous coherent muon-spin precession below the metal-insulator
transition (MIT) temperature of about 33 K is observed, indicating the
appearance of a long-ranged magnetic ordering of Ir moments. With
further decrease in temperature, the internal field at the muon site increases
again below about 9 K. The second increase of internal field suggests the
ordering of Nd moments, which is consistent with a previous neutron
experiment. Our results suggest that the MIT and magnetic ordering of Ir
moments have a close relationship and that the large spin-orbit coupling of Ir
5\textit{d} electrons plays a key role for both MIT and the mechanism of the
magnetic ordering in pyrochlore iridates in the insulting ground state.Comment: 5 pages, 3 figures. Accepted by Physical Review B (rapid
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