We consider Schrödinger equations for
N
number of particles in (classical) electro-magnetic fields that are interacting with each other via time dependent inter-particle potentials. We prove that ...they uniquely generate unitary propagators
{
U
(
t
,
s
)
,
t
,
s
∈
R
}
on the state space
H
under the conditions that fields are spatially smooth and do not grow too rapidly at infinity so that propagators for single particles satisfy Strichartz estimates locally in time, and that local singularities of inter-particle potentials are not too strong that time frozen Hamiltonians define natural selfadjoint realizations in
H
. We also show, under very mild additional assumptions on the time derivative of inter-particle potentials, that propagators possess the domain of definition of the quantum harmonic oscillator
Σ
(
2
)
as an invariant subspace such that, for initial states in
Σ
(
2
)
, solutions are
C
1
functions of the time variable with values in
H
. New estimates of Strichartz type for propagators for
N
independent particles in the field will be proved and used in the proof.
Abstract
To formulate necessary protective measures after a large-scale nuclear accident, it is crucial to understand the levels of radiation to which persons living in radionuclide-contaminated ...areas are exposed. Individual monitoring using personal dosemeters (PDs) plays a role in this, although PDs were not originally intended to be used by members of the public. The present study investigated PD responses in areas highly affected by the Fukushima Daiichi nuclear accident, as well as the dependence of those measurements on body size. Three types of commercially available electronic PDs, including D-shuttle, which has often been used in Fukushima, were placed on the front surfaces of three age-specific anthropometric phantoms imitating a 5-y-old, a 10-y-old and an adult male, and these phantoms were then exposed to radiation in an open field in the affected area. In the case of D-shuttle, the ratios of PD readings to the ambient dose rate for the 5-y-old phantom and the adult male phantom were 0.79 and 0.72, respectively. The ratios were somewhat higher for the other PDs; any PDs showed higher readings than the effective doses estimated by simulations based on the assumed ground deposition of 134Cs and/or 137Cs over the affected areas.
Purpose
Bowel wall enhancement on CT imaging is considered one of the useful features for the prediction of the presence of irreversible ischemic change in patients with small bowel obstruction. ...However, the applicability of CT imaging in patients with incarcerated hernias has not been investigated in detail. The aim of this retrospective study was to evaluate the feasibility of preoperative CT findings for the prediction of the presence of irreversible ischemic change in patients with incarcerated hernias containing small bowel.
Methods
Included in this study were 76 patients who underwent surgery for preoperatively diagnosed incarcerated hernias containing small bowel (27 inguinal hernias, 37 femoral hernias and 12 obturator hernias) at our hospital between January 2011 and June 2020. The preoperative clinicoradiological features were compared between the groups, and predictors for intestinal resection were evaluated.
Results
Nineteen patients required intestinal resection (Resection group), and the other 57 patients did not require intestinal resection (Nonresection group). Multivariate analyses revealed that age ≥ 80 years (
p
= 0.018, odds ratio = 6.604) and the absence of bowel wall enhancement (
p
= 0.032, odds ratio = 51.200) were independent predictors for intestinal resection. In resected specimens, all patients with an absence of bowel wall enhancement on preoperative enhanced CT had ischemic changes extending beyond the muscularis propria.
Conclusions
Preoperative enhancement CT yields useful information for the prediction of the presence of irreversible ischemic change in patients with incarcerated hernias containing small bowel.
Transient currents in AlGaN/GaN High Electron Mobility Transistors (HEMTs) induced by focused ion beams are measured. Enhanced charge collection occurs in the on- and pinch-off states of AlGaN/GaN ...HEMTs. The first-order mechanism of enhancement is associated with bipolar and back-channel effects. In addition, we suggest that the temporal positive charge buildup contributes to the enhanced charge collection. The effect of displacement damage on the enhanced charge collection is also discussed.
Experiments were carried out in a small enclosed booth for the purpose of understanding and modelling (218)Po behaviour. The experiment was conducted under two kinds of conditions without and with ...injection of incense smoke. A working model of (218)Po behaviour was applied to analyse the measured data. Under the condition without incense smoke, temporal changes in aerosol-attached and unattached (218)Po concentrations were successfully reproduced by the model. The deposition rate of unattached fraction and the rate of attachment were determined by the working model. Under the condition with incense smoke, temporal changes in (218)Po concentration were poorly simulated by the model. This can be attributed to the significantly increased aerosol concentration in small size ranges which is not properly considered in the attachment rate calculation in the model.
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