952 research outputs found
A possible observational evidence for angular distribution of opening half-angle of GRB jets
We propose a method to estimate the pseudo jet opening half-angle of GRBs
using the spectral peak energy (\Ep)--peak luminosity relation (so called
Yonetoku relation) as well as the \Ep--collimation-corrected -ray
energy relation (so called Ghirlanda relation). For bursts with known jet break
times and redshifts, we compared the pseudo jet opening half-angle with the
standard one and found that the differences are within a factor 2. We apply the
method to 689 long GRBS. We found that the distribution function of the pseudo
jet opening half-angle obeys with
possible cutoffs for although the
log-normal fit is also possible. distribution is compatible with
the structured jet model. From the distribution function we found that the
beaming correction for the rate of GRBs is , which means yr galaxy or only one in type Ib/c supernovae. We
also found the evolution of the distribution function as a function of the
redshift.Comment: 5 pages, 5 figures, submitted to MNRA
モリシマアカシアの全木パルプ化に関する基礎的研究
全木パルプ化に関する基礎的データを蓄積する目的で, モリシマアカシア各部位をパルプ化し, 組織構成要素および紙質と関連づけて研究した。その結果, アカシア樹皮の師部繊維は木繊維より大きい繊維長を持ち, これが全木パルプシートにおける紙力向上に寄与することから, アカシアが全木パルプ化に適した樹種であると推定し得た。なお, 樹皮には製紙に際して悪影響を及ぼすと考えられる要素がほとんど存在しないが, 未さらし全木パルプには易漂白性の褐色斑点が存在する
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