3,379 research outputs found
Coulomb Breakup Mechanism of Neutron-Halo Nuclei in a Time-Dependent Method
The mechanism of the Coulomb breakup reactions of the nuclei with
neutron-halo structure is investigated in detail. A time-dependent
Schr\"odinger equation for the halo neutron is numerically solved by treating
the Coulomb field of a target as an external field. The momentum distribution
and the post-acceleration effect of the final fragments are discussed in a
fully quantum mechanical way to clarify the limitation of the intuitive picture
based on the classical mechanics. The theory is applied to the Coulomb breakup
reaction of Be + Pb. The breakup mechanism is found to be
different between the channels of and
, reflecting the underlying structure of Be. The
calculated result reproduces the energy spectrum of the breakup fragments
reasonably well, but explains only about a half of the observed longitudinal
momentum difference.Comment: 15 pages,revtex, 9 figures (available upon request
Application of transparent microperforated panels to acrylic partitions for desktop use: A case study by prototyping
There are various measures currently in place to prevent the spread of coronavirus (COVID-19); however, in some cases, these can have an adverse effect on the acoustic environment in buildings. For example, transparent acrylic partitions are often used in eating establishments, meeting rooms, offices, etc., to prevent droplet infection. However, acrylic partitions are acoustically reflective; therefore, reflected sounds may cause acoustic problems such as difficulties in conversation or the leakage of conversation. In this study, we performed a prototyping of transparent acrylic partitions to which a microperforated panel (MPP) was applied for sound absorption while maintaining transparency. The proposed partition is a triple-leaf acrylic partition with a single acrylic sheet without holes between two MPP sheets, as including a hole-free panel is important to prevent possible droplet penetration. The sound absorption characteristics were investigated by measuring the sound absorption in a reverberation room. As the original prototype showed sound absorption characteristics with a gentle peak and low values due to the openings on the periphery, it was modified by closing the openings on the top and sides. The sound absorption performance was improved to some extent when the top and sides were closed, although there remains the possibility of further improvement. For this study, only the sound absorption characteristics were examined in the prototype experiments. The effects during actual use will be the subject of future study
Confirmation of a one-dimensional spin-1/2 Heisenberg system with ferromagnetic first-nearest-neighbor and antiferromagnetic second-nearest-neighbor interactions in RbCuMoO
We have investigated magnetic properties of RbCuMoO
powder. Temperature dependence of magnetic susceptibility and magnetic-field
dependence of magnetization have shown that this cuprate is a model compound of
a one-dimensional spin-1/2 Heisenberg system with ferromagnetic
first-nearest-neighbor (1NN) and antiferromagnetic second-nearest-neighbor
(2NN) competing interactions (competing system). Values of the 1NN and 2NN
interactions are estimated as K and K (). This value of suggests that the ground state is a
spin-singlet incommensurate state. In spite of relatively large and
, no magnetic phase transition appears down to 2 K, while an
antiferromagnetic transition occurs in other model compounds of the competing
system with ferromagnetic 1NN interaction. For that reason,
RbCuMoO is an ideal model compound to study properties of
the incommensurate ground state that are unconfirmed experimentally.Comment: 6 pages, 4 figure
Response of okra (Abelmoschus esculentus (L.) Moench) and soil chemical properties to different amendment types in an ultisol
A field experiment was carried out to investigate the effect of different organic manure on the growth and yield of okra (Abelmoschus esculentus (L.) Moench) at the teaching and research farm of the University of Benin, Benin City, Edo State, Nigeria between April to August, 2016. Four treatments; control (T1), cattle dung + poultry manure + pig manure (T2), poultry manure + foliar blend (T3) and bacterial inoculant (T4) were laid out in a randomized complete block design with four replications. Data were collected on growth (plant height, number of leaves, stem girth and leaf area) and yield parameters of okra plant. Results obtained from the research indicated that the growth and yield of okra was lowest in control (T1). These results further suggest that, the organic manure used in the study especially in a combined form (cattle dung + poultry manure + pig manure) positively influenced the agronomic performance of the okra plant. T2 increased okra plant height and, leaf area compared with the control. T3 recorded significantly higher number of leaves (7.188), compared with the control (3.375) whereas, fresh fruit weight from the various treatment plots were in the following order; T2 (79.15g) > T3 (53.58g) > T4 (22.53g) > T1 (20.24g). Although the nitrogen content of the soil was higher (21.33 g/kg) with T4, the highest fruit weight was obtained in T2 treated soils. It was also observed from the microbial analysis carried out on the soil samples obtained from the various plots that, soils with organic amendments (T2, T3 and T4) generally had higher microbial population, relative to control (T1). Based on the findings of this experiment, it could be deduced that cattle dung, poultry manure and pig manure promotes higher performance of okra.
 
Unequal effects of renin-angiotensin system inhibitors in acute cardiac dysfunction induced by isoproterenol
Ohta, T; Hasebe, N; Tsuji, S; Izawa, K; Jin, YT; Kido, S; Natori, S; Sato, M; Kikuchi, K, AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, 287(6), H2914-H2921, 2004. "Copyright 2004 by the American Physical Society."
publisherSeveral clinical trials have demonstrated that angiotensin-converting enzyme inhibitor (ACEI) and angiotensin II type 1 receptor blocker (ARB) are equally effective in the treatment of chronic heart failure. However, this has not been confirmed for acute cardiac dysfunction. We examined whether ACEI or ARB prevents isoproterenol-induced acute left ventricular (LV) dysfunction in dogs. LV dysfunction induced by a large dose of isoproterenol (1 µg·kg^–1·min^–1, 3-h infusion) was compared in dogs treated with ACEI (temocaprilat) or ARB (olmesartan). Atrial pacing induced a constant heart rate and use of adjustable aortic banding provided a nearly constant afterload. LV systolic function (LV dP/dt, fractional shortening, and ejection fraction) and diastolic function (γ and LV end-diastolic pressure) were significantly deteriorated after isoproterenol infusion. The LV dysfunction was almost totally prevented by ARB but was only partially prevented by ACEI. The partial effect of ACEI was complemented by cotreatment with HOE-140, a bradykinin B_2 receptor antagonist. At baseline, the response to low doses of isoproterenol was significantly attenuated by ACEI but not by ARB, and the ACEI-induced attenuation was totally abolished by cotreatment with HOE-140. The response to isoproterenol was significantly attenuated after 3 h of excess isoproterenol loading, and it was almost completely preserved by ARB but not by ACEI. In conclusion, acute LV dysfunction and β-adrenergic desensitization induced by excess isoproterenol administration were almost totally prevented by ARB but only partially prevented by ACEI. These differences were attributable at least in part to bradykinin pathways activated by ACEI administration in acute LV dysfunction
Dynamical Casimir effect for TE and TM modes in a resonant cavity bisected by a plasma sheet
Parametric photon creation via the dynamical Casimir effect (DCE) is
evaluated numerically, in a three-dimensional rectangular resonant cavity
bisected by a semiconductor diaphragm (SD), which is irradiated by a pulsed
laser with frequency of GHz order. The aim of this paper is to determine some
of the optimum conditions required to detect DCE photons relevant to a novel
experimental detection system. We expand upon the thin plasma sheet model
[Crocce et al., Phys. Rev. A 70 033811 (2004)] to estimate the number of
photons for both TE and TM modes at any given SD position. Numerical
calculations are performed considering up to 51 inter-mode couplings by varying
the SD location, driving period and laser power without any perturbations. It
is found that the number of photons created for TE modes strongly depends on SD
position, where the strongest enhancement occurs at the midpoint (not near the
cavity wall); while TM modes have weak dependence on SD position. Another
important finding is the fact that significant photon production for TM
modes still takes place at the midpoint even for a low laser power of 0.01
micro J/pulse, although the number of TE photons decreases almost
proportionately with laser power. We also find a relatively wide tuning range
for both TE and TM modes that is correlated with the frequency variation of the
instantaneous mode functions caused by the interaction between the cavity
photons and conduction electrons in the SD excited by a pulsed laser.Comment: 9 pages, 8 figure files; version 2, minor grammatical changes and two
references added; version 4 agrees with version in Phys. Rev. A; DOI no.
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