558 research outputs found
A spin Esaki diode
We demonstrate electrical electron spin injection via interband tunneling in
ferromagnetic/nonmagnetic semiconductor Esaki diodes. An interband tunnel
junction between ferromagnetic p+-(Ga,Mn)As and nonmagnetic n+-GaAs under
reverse-bias allows spin-polarized tunneling of electrons from the valence band
of (Ga,Mn)As to the conduction band of n+-GaAs. The spin polarization of
tunneled electrons is probed by circular polarization of electroluminescence
(EL) from an n-GaAs/InGaAs/p-GaAs light emitting structure integrated with the
diode. Clear hysteresis loop with +-6.5% remanence is observed in the
magnetic-field dependence of the EL polarization at 6 K, below the Curie
temperature of (Ga,Mn)As.Comment: 11pages, 4figures. Submitted Japanese Journal of Applied Physics Pt2
Express Lette
Time-evolution of Peak Energy and Luminosity Relation within Pulses for GRB 061007: Probing Fireball Dynamics
We perform a time-resolved spectral analysis of bright, long Gamma-ray burst
GRB 061007 using Suzaku/WAM and Swift/BAT. Thanks to the large effective area
of the WAM, we can investigate the time evolution of the spectral peak energy,
Et_peak and the luminosity Lt_iso with 1-sec time resolution, and we find that
luminosity Lt_iso with 1-sec time resolution, and we find that the
time-resolved pulses also satisfy the Epeak-Liso relation, which was found for
the time-averaged spectra of other bursts, suggesting the same physical
conditions in each pulse. Furthermore, the initial rising phase of each pulse
could be an outlier of this relation with higher Et_peak value by about factor
2. This difference could suggest that the fireball radius expands by a factor
of 2-4 and/or bulk Lorentz factor of the fireball is decelerated by a factor of
4 during the initial phase, providing a new probe of the fireball dynamics in
real time.Comment: 21 pages, 16 figures, accepted for publication in PAS
Improvement of Translation Accuracy for the Outlines of Japanese Statutes by Splitting Parenthesized Expressions
To globally share Japanese legal information, we translate the Outlines of Japanese statutes. These outlines are the official summaries of Japanese statutes and are useful to quickly understand their contents. In a previous statistical machine translation system for the outlines, we found that the training corpus consisted of both statutes and their outlines, including many long sentences that reduced the translation quality. To solve this problem, we shortened the length of sentences and focused on parenthesized expressions. In this paper, we propose a translation method that splits off parenthesized expressions from the sentences. Experimental result shows the effectiveness of our method
Daily News on Japanese Legislation toward Global Sharing of Japanese Legal Information
Our purpose in this paper is to develop a system for the international sharing of Japanese legal information. We plan to promptly provide the Outlines of all the newly promulgated Japanese statutes in English, using machine translation. Structured documents in XML format made it possible to achieve various functions concerning machine translation, text search, and display style. We developed the Document Type Definition for the Outlines based on our investigation of their structure. We also developed a rule-based annotator for the Outlines, which adequately marked up 87.2% on the Outlines of Japanese acts
Combined Gastrectomy with Adjacent Organs in T4 Gastric Cancer : Therapeutic Results and Indication
The postoperative morbidity, mortality and survival of 244 T4 gastric cancer patients were examined to assess the therapeutic results and to clarify the indication for combined gastrectomy with adjacent (T4) organs. A total of 190 combined and 54 simple gastrectomies were performed during the 25-year period between 1969 and 1994. Fourteen (7.4%) and 7 (13.0%) patients died of the complications after combined and simple gastrectomies respectively. No statistical significant difference was found in the mortality rates between the gastrectomies. The histological examination of 190 resected specimens by the combined gastrectomy with T4 organs revealed that gastric resections with conclusive curability A, B and C were performed in 33 (17.4%), 84 (44.2%) and 73 (38.4%) cases respectively. Significant differences (P < 0.01) among 3 survival curves of the patients with curability A, B and C were found, and the 5-year survival rates were 65.5%, 35.4% and 9.2% respectively. The survival curve of 176 patients with combined gastrectomy was significantly (P < 0.01) higher than that of 47 patients with simple gastrectomy, and the 5-year survival rates were 31.3% and 4.3%. However, the survival curve and the 5-year survival rate of the patients with simple gastrectomy were not statistically different from those of the patients with curability C. These results suggest that combined gastrectomy with T4 organs in T4 gastric cancer may be indicated for the patients with surgical curability B, but not surgical curability C
NHC-catalyzed cleavage of vicinal diketones and triketones followed by insertion of enones and ynones
Thiazolium carbene-catalyzed reactions of 1,2-diketones and 1,2,3-triketones with enones and ynones have been investigated. The diketones gave α,β-double acylation products via unique Breslow intermediates isolable as acid salts, whereas the triketones formed stable adducts with the NHC instead of the coupling products
Creation of Mo/Tc@C60 and Au@C60 and molecular-dynamics simulations
The formation of middle- and/or high-weight atom (Mo, Au)-incorporated fullerenes was investigated using radionuclides produced by nuclear reactions. From the trace radioactivities of ⁹⁹Mo/⁹⁹mTc or ¹⁹⁴Au after high-performance liquid chromatography, it was found that the formation of endohedral and/or heterofullerene fullerenes in ⁹⁹Mo/⁹⁹mTc and ¹⁹⁴Au atoms could occur by a recoil process following the nuclear reactions. Furthermore, the ⁹⁹mTc (and ¹⁹⁴Au) atoms recoiled against β-decay remained present inside these cages. To confirm the produced materials experimentally, ab initio molecular dynamics (MD) simulations based on an all-electron mixed-basis approach were performed. The possibility of the formation of endohedral fullerenes containing Mo/Tc and Au atoms is verified; here, the formation of heterofullerenes is excluded by MD simulations. These findings suggest that radionuclides stably encapsulated by fullerenes could potentially play a valuable role in diagnostic nuclear medicine
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