394 research outputs found
Quasi-Elastic Reaction and Spin Response Functions of the Deuteron
We calculated response functions of the deuteron for charge exchange
processes, including the final state interaction between two protons. Using
them we evaluated the double differential cross section and polarization
observables of by means of plane wave impulse
approximation with an optimal factorization. Calculation well reproduced the
shape of the energy spectra of the cross section, though somewhat overestimated
the magnitude. It also reproduced the spin observables well.Comment: 19 pages of LaTeX (4 figures not included, hard copy available upon
request), UT-Komaba 93-2
Development of a New DNA Marker for Fusarium Yellows Resistance in Brassica rapa Vegetables
In vegetables of Brassica rapa L., Fusarium oxysporum f. sp. rapae (For) or F. oxysporum f. sp. conglutinans (Foc) cause Fusarium yellows. A resistance gene against Foc (FocBr1) has been identified, and deletion of this gene results in susceptibility (focbr1-1). In contrast, a resistance gene against For has not been identified. Inoculation tests showed that lines resistant to Foc were also resistant to For, and lines susceptible to Foc were susceptible to For. However, prediction of disease resistance by a dominant DNA marker on FocBr1 (Bra012688m) was not associated with disease resistance of For in some komatsuna lines using an inoculation test. QTL-seq using four F2 populations derived from For susceptible and resistant lines showed one causative locus on chromosome A03, which covers FocBr1. Comparison of the amino acid sequence of FocBr1 between susceptible and resistant alleles (FocBr1 and FocBo1) showed that six amino acid differences were specific to susceptible lines. The presence and absence of FocBr1 is consistent with For resistance in F2 populations. These results indicate that FocBr1 is essential for For resistance, and changed amino acid sequences result in susceptibility to For. This susceptible allele is termed focbr1-2, and a new DNA marker (focbr1-2m) for detection of the focbr1-2 allele was develope
Fine-tuning of the size of supramolecular nanotoroids suppresses the subsequent catenation of nano-[2]catenane
A judicious combination of ring-closing supramolecular polymerization and secondary nucleation can hierarchically organize a diphenylnaphthalene barbiturate monomer bearing a 3,4,5-tri(dodecyloxy)benzyloxy unit into self-assembled nano-polycatenanes composed of nanotoroids. In our previous study, nano-polycatenanes of variable length have been formed uncontrollably from the monomer that provides nanotoroids with sufficiently wide inner void space wherein secondary nucleation is driven by non-specific solvophobic interaction. In this study, we found that the elongation of the alkyl chain length of the barbiturate monomer decreases the inner void space of nanotoroids while increasing the frequency of secondary nucleation. These two effects resulted in an increase in the yield of nano-[2]catenane. This unique property observed in our self-assembled nanocatenanes might be extended to a controlled synthesis of covalent polycatenanes using non-specific interactions
Hierarchically Porous ZSM-5 Synthesized by Nonionic- and Cationic-Templating Routes and Their Catalytic Activity in Liquid-Phase Esterification
Hierarchically porous MFI zeolites (ZSM-5) have been synthesized by hydrothermal treatment in the presence of trialkoxysilylated-derivatives of nonionic poly(oxyethylene) alkyl ether or alkyl quaternary ammonium cation as mesopore-generating agent, along with tetrapropylammonium cation as zeolite structure-directing agent. Powder X-ray diffraction revealed that zeolites have been crystallized, and scanning electron microscopy showed rugged surface morphology that was quite different from conventional ZSM-5. The mesoporosity was confirmed by nitrogen adsorption-desorption measurement showing type IV isotherms with narrow distribution of mesopore diameters. The catalytic activity of these mesoporous ZSM-5 was tested in liquid-phase esterification of benzyl alcohol with hexanoic acid. The conversion of benzyl alcohol on mesoporous ZSM-5 prepared via cationic-templating route was almost 100%, being much higher than on mesoporous ZSM-5 prepared with silylated nonionic surfactant as well as on conventional ZSM-5 with no mesopores. The presence of Brønsted acid sites, together with the mesopores, was responsible for this catalytic conversion, as confirmed by pyridine adsorption monitored by in situ infrared and 27Al magic angle spinning nuclear magnetic resonance spectroscopy
Distorted wave impulse approximation analysis for spin observables in nucleon quasi-elastic scattering and enhancement of the spin-longitudinal response
We present a formalism of distorted wave impulse approximation (DWIA) for
analyzing spin observables in nucleon inelastic and charge exchange reactions
leading to the continuum. It utilizes response functions calculated by the
continuum random phase approximation (RPA), which include the effective mass,
the spreading widths and the \Delta degrees of freedom. The Fermi motion is
treated by the optimal factorization, and the non-locality of the
nucleon-nucleon t-matrix by an averaged reaction plane approximation. By using
the formalism we calculated the spin-longitudinal and the spin-transverse cross
sections, ID_q and ID_p, of 12C, 40Ca (\vec{p},\vec{n}) at 494 and 346 MeV. The
calculation reasonably reproduced the observed ID_q, which is consistent with
the predicted enhancement of the spin-longitudinal response function R_L.
However, the observed ID_p is much larger than the calculated one, which was
consistent with neither the predicted quenching nor the spin-transverse
response function R_T obtained by the (e,e') scattering. The Landau-Migdal
parameter g'_N\Delta for the N\Delta transition interaction and the effective
mass at the nuclear center m^*(r=0) are treated as adjustable parameters. The
present analysis indicates that the smaller g'_{N\Delta}(\approx 0.3) and
m^*(0) \approx 0.7 m are preferable. We also investigate the validity of the
plane wave impulse approximation (PWIA) with the effective nucleon number
approximation for the absorption, by means of which R_L and R_T have
conventionally been extracted.Comment: RevTex 3, 29 pages, 2 tables, 8 figure
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