Systematic measurements and calculations of neutron capture cross sections and capture gamma-ray spectra of all stable Se isotopes ^(74, 76, 77, 78, 80, 82)Se were performed in a neutron energy ...region from 10 to 600 keV, using a pulsed neutron source by the ^7Li(p,n)^7Be reaction. Highly isotopically enriched Se samples and standard Au samples were used. The capture gamma rays from each sample were detected with an anti-Compton NaI(Tl) spectrometer by means of a time-of-flight method. The capture cross sections were derived by using a pulse-height weighting technique and the standard capture cross sections of ^(197)Au. The capture gamma-ray spectra were obtained by unfolding the observed capture gamma-ray pulse-height spectra. In the calculations, a computer code, POD, was utilized. The calculated results were compared with the experimental results. The present experimental and calculated results were compared with previous measurements and evaluated values. KCI Citation Count: 3
In this paper a purely algebraic condition for a word in a free group to be representable by a simple curve on a punctured plane will be given.
As an application, an algorithm for simple closed ...curves on a punctured plane will be obtained. Our solution is different from any algorithm due to Reinhart Ann. of Math. 75 (1962) 209, Zieschang Math. Scand. 17 (1965) 17 or Chillingworth Bull. London Math. Soc. 1 (1969) 310. Although the study here will be confined to the case of a plane, similar arguments could be carried out on the 2-sphere. This research was motivated by monodromy problems appearing in Lefschetz fibrations and surface braids. See Math. Proc. Cambridge Philos. Soc. 120 (1996) 237; Kamada, Braid and Knots Theory in Dimension Four, American Mathematical Society, 2002; Kamada and Matsumoto, in: Proceedings of the International Conference on Knot Theory “Knots in Hellas '98”, World Scientific, 2000, p. 118; Kamada and Matsumoto, Enveloping monoidal quandles, Preprint, 2002; Matsumoto, in: S. Kojima et al. (Eds.), Proc. the 37th Taniguchi Sympos., World Scientific, 1996, p. 123.
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Enveloping monoidal quandles Kamada, Seiichi; Matsumoto, Yukio
Topology and its applications,
2005, 2005-01-00, Volume:
146
Journal Article
Peer reviewed
Open access
A quandle is a set with a self-distributive binary operation satisfying a certain condition. Here we construct a monoid (a semi-group with the identity) associated with a quandle. This monoid has a ...structure of a quandle, which contains the original quandle as a sub-quandle. We call it the enveloping monoidal quandle. The purpose of this paper is to introduce the notion of the enveloping monoidal quandle, and to investigate it.
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The present paper presents the measurement of neutron induced activations on concrete using the 64.5MeV quasimonoenergetic neutrons produced at the intense (7)Li(p,n) neutron source at Cyclotron and ...Radioisotope Center, Tohoku Univeristy (CYRIC). The data were corrected for the effect of continuous neutrons in the source. The neutron energy, neutron yields and the spectrum of continuous neutrons were confirmed with the neutron time-of-flight method and the neutron activation measurement of the (2(0(9)Bi(n,Xn) reactions having various threshold energy values. The nuclides produced by thermalized source neutrons are negligible. New data were obtained for concrete activation.
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The formation and texture of Bi-2223 phase during sintering in high magnetic fields were investigated. Samples contained in silver crucibles were sintered at different temperatures from 835 to 860 °C ...for 120 h in a vertical tube furnace installed in a solenoid-type superconducting magnet. A vertical magnetic field,
H
a of 10 T can be applied parallel to the long axis of the furnace. It has been found that the mixed structures of the Bi-2223 and the Bi-2212 grains with their
c-axis parallel to the magnetic field are formed in samples sintered at 850–855 °C in 10 T magnetic field. Below 845 °C sintering in 10 T, a high proportion of Bi-2223 phase is obtained, however no preferred orientation is observed. It is suggested that a liquid phase is important for the formation of the textured structure in magnetic fields.
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Recent evidence suggested that nitric oxide (NO) acts as an important factor in a variety of physiological and pathological roles, including reproductive functions. The purpose of the present study ...was to investigate whether NO might significantly induce any change in steroidogenesis in cultured porcine granulosa cells (PGC). An NO donor, NOC18, significantly suppressed the oestradiol release from basal (unstimulated) and gonadotrophin-stimulated PGC in a 2 h culture. NOC18 also significantly inhibited the aromatase activity of basal and gonadotrophin-stimulated PGC as measured by a modified tritiated water method. However, the cGMP analogue, 8-bromo-cGMP, had no significant effect on the accumulation of oestradiol and progesterone in basal and gonadotrophin-stimulated PGC during 24 h culture. An NO synthase (NOS) inhibitor, NG-monomethyl-L-arginine (LNMMA), significantly stimulated the basal oestradiol release and dose-dependently enhanced the oestradiol and progesterone release from follicle stimulating hormone (FSH)-stimulated PGC in a 24 h culture. However, NG-monomethyl-D-arginine, which does not inhibit NOS, did not enhance the release of oestradiol and progesterone under the same experimental conditions. LNMMA also significantly suppressed the nitrite concentrations in the media as measured by chemiluminescence. These results demonstrate for the first time that NO inhibits oestradiol secretion independent of cGMP by inhibiting P450 aromatase activity in moderately mature PGC.
An intense 7Li(p,n) neutron source was installed with the K = 110-MeV azimuthally varying field (AVF) cyclotron at the Cyclotron and Radioisotope Center (CYRIC), Tohoku University, by employing a ...special arrangement to allow a short target-sample distance down to 1 m. The source can deliver a neutron flux around 1.5 × 106 n cm−2 s−1 with a lithium target of thickness equivalent to 2-MeV energy loss and 3-µA proton beam, which is the highest intensity in the world. The source is successfully used for (1) measurement of neutron cross sections relevant to radiation safety and radiation effect and (2) semiconductor irradiation test for single-event effect and (3) characterisation of neutron detectors and dosemeters.
The crystal growth of Bi-2201 phase during partial-melting and solidification in high magnetic fields was reported. Thin crystals (∼20 μm) with a size of 5–10 mm
2 exist only in the surface layers of ...samples treated in zero magnetic field. Whereas thick crystals (∼100 μm) exist not only on the surface, but also in the center of samples treated in 8 T magnetic fiel.
T
c of Bi-2201 phase treated in 0 T is higher than that treated in 8 T. Bi-2201 phase and Bi-2212 phase coexist in the sample treated in 0 T, whereas only Bi-2201 phase exists in the sample treated in 8 T. For the sample treated in 8 T magnetic field, a clear second peak structure was observed in the magnetic hysteresis loop in the direction
H
m∥
H
a at 5 K, and the width of the hysteresis loop
ΔM at 5 K and 0 T in the direction
H
m∥
H
a is about 10 times as large as that in the direction
H
m⊥
H
a, indicating that for this sample an obvious anisotropy exists and the Bi-2201 grains align with their
c-axes parallel to
H
a.
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The 2-twist spun trefoil is an example of a sphere that is knotted in 4-dimensional space. A proof is given in this paper that this sphere is distinct from the same sphere with its orientation ...reversed. Our proof is based on a state-sum invariant for knotted surfaces developed via a cohomology theory of racks and quandles (also known as distributive groupoids).
A quandle is a set with a binary operation — the axioms of which model the Reidemeister moves in classical knot theory. Colorings of diagrams of knotted curves and surfaces by quandle elements, together with cocycles of quandles, are used to define state-sum invariants for knotted circles in 3-space and knotted surfaces in 4-space.
Cohomology groups of various quandles are computed herein and applied to the study of the state-sum invariants. Non-triviality of the invariants is proved for a variety of knots and links, and conversely, knot invariants are used to prove non-triviality of cohomology for a variety of quandles.
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