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1.
D. Krupp 《辐射效应与固体损伤》2019,174(11-12):1047-1052
ABSTRACTIn a novel approach using blended learning techniques members of the CHERNE network have organized novel courses. This report covers a course in Radiochemistry and Medical Dosimetry. Homework assignments on the global sustainability tools laid the foundation of simulation work on cyclotron targetry and radiochemical laboratory courses. A role play game on Medical Dosimetry concluded the one week of instructions. For the next course, the first year students prepare an instruction scheme for another batch of students and will give that instruction themselves. 相似文献
2.
V. I. Tikhomirov 《Isotopes in environmental and health studies》2013,49(3-4):273-280
Abstract In the course of studies of the layered intrusion Kiwakka about 70 samples of rocks and minerals have been investigated. The oxydation reagent ClF3 was used to extract oxygen from the samples. The obtained δ18O-values show a significant differentiation of the intrusion itself in dependence of its petrographic composition. The conclusion can be drawn that the intrusion has formed under conditions of a closed system and that the magmatic fluid does not contain meteoric water, possibly. 相似文献
3.
4.
S. Karashima 《辐射效应与固体损伤》2013,168(1-3):215-219
Abstract The stopping power and range for Xe ions in high temperature matter (partially ionized plasmas) have been calculated using the dielectric response function method. Calculations have been made for a target matter Al (Z = 13) over a wide range of temperatures and densities considering a finite temperature model. The stopping powers obtained have smaller values in comparison with those of a zero temperature model. The stopping power strongly depends on the density and temperature of the target material, and the projectile ion energy. 相似文献
5.
S. Keller 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,13(1):51-59
Triple differential cross-sections (TDCS) for (
e
,2
e
) processes on C60 have been calculated in the plane wave Born and distorted wave Born approximations using a jellium shell model to describe
the target valence states. The peculiarities of these TDCS are demonstrated by comparison with results for atomic hydrogen.
Ionisation into a resonant state leads to dramatic modifications of the TDCS. This effect could also be observed in a surface
(
e
,2
e
) experiment in specular geometry using a thin film of physisorbed C60.
Received 14 April 2000 and Received in final form 27 July 2000 相似文献
6.
D. G. Haase C. R. Gould J. E. Koster N. R. Roberson L. W. Seagondollar J. P. Soderstrum M. B. Schneider X. Zhu 《Hyperfine Interactions》1988,43(1-4):133-138
We describe searches for parity and time reversal violations in the scattering of polarized neutrons from polarized and aligned165Ho targets. We have completed a search with 7.1 and 11.0 MeV neutrons for PoddTodd terms in the elastic scattering forward amplitude of the form s. (I×K), wheres is the neutron spin,I is the target spin andk is the neutron momentum vector. The target was a single crystal of holmium, polarized horizontally along itsb axis by a 1 Tesla magnetic field. The neutrons were polarized vertically. Differences in the neutron transmission were measured
for neutrons with spins parallel (antiparallel) toI×k. The P,T violating analyzing powers were found to be consistent with zero at the few 10−3 level: ρP,T(7.1 MeV)=−0.88 (±2.02) x 10−3, ρP,T(11.0 MeV)=−0.4 (±2.88) x 10−3. We have also attempted to find enhancements with MeV neutrons in P-violation due to the term s\k. We are preparing an aligned target cryostat for investigations of PevenTodd terms {bd(I\k)(I×k)\s} in neutron scattering. The target will be a single crystal cylinder of165Ho cooled to 100 mK in a bath of liquid helium and rotated by a shaft from a room temperature stepping motor. The cylinder
will be oriented vertically and the alignment (c) axis oriented horizontally. Warming or rotation of the sample allows one to separate effects that mimic the sought-after
time reversal violating term. 相似文献
7.
In this paper, we have presented a range of new nitro-stilbene derivatives with benzophenones via ether or ester bridged bond.
These nitro-stilbene derivatives with benzophenones have been conveniently obtained by condensation reaction. The linked benzophenones
were efficiently introduced to nitro-stilbene dyes. The structures of these compounds have been characterized with NMR and
element analysis. The single crystals of two target compounds (11 and 12) have been obtained, and their X-ray crystallographic data have been determined and discussed. Remarkably different absorption
and fluorescence spectroscopy was observed for nitro-stilbene derivatives with benzophenones via different linked bonds. The
results show that electron-donating or electron withdrawing bridged bonds have significant influence on the absorption and
fluorescence spectroscopy, which makes it possible for the development of ideal nitro-stilbene dyes with benzophenones through
chemical strategy. 相似文献
8.
Abstract Structural aspects of the direct graphite-diamond transition have been studied along with the reaction P-T-hysteresis arising during phase transformations in carbon. The direct transition has been found to be a high-molecular reaction of cross-linking of two-dimensional graphite networks resulting in their transformation into three-dinensions1 covalent networks of diamond. Crystal-oriented barochemical reaction of cross-linking is described by two fundamental matrices: the matrix of atomic coordinates transformation and the matrix of atomic concentration Jump. A method of hi&-molecular thermomechanics developed in this paper is used to discuss P-T-hysteresis that was experimentally observed in, the direct and inverse transitions in carbon. 相似文献
9.
Abstract Laser-driven shock wave propagation in a transparent material such as Plexiglas coated with a thin overlayer of gold is studied using the technique of high speed optical shadowgraphy. A Nd: glass laser was focussed to produce intensities in the range of 10′2-10′4W/cm2 on the target, within an irradiation spot diameter of 160 pm, optical shadowgrams were recorded bya second harmonic (0.53 pm wavelength) pulse. Shock pressures and scaling of pressure with laser intensity was studied. Shock pressures in gold-coated Plexiglas target was observed to be considerably higher compared to those in uncoated targets. This enhancement of shock pressure has been explained on the basis of contribution of an X-ray driven ablative heat wave in the gold plasma. Shock pressure values show a close agreement with those obtained from a one-dimensional Langrangian hydrodynamic simulation. Shadowgrams of shock fronts produced by non-uniform spatial laser beam irradiation profiles have shown complete smoothing when a gold layer is used on a Plexiglas target. 相似文献
10.
《Journal of voice》2020,34(2):302.e21-302.e28
ObjectiveThe main purpose of this study is to investigate the effectiveness of a 12-week holistic vocal training program designed for theatre students.MethodsThe participants included 10 female and 8 male students, who were third- and fourth-year students of a state conservatory theatre department. Participants randomly selected from among those who were between the ages of 18–30 years, had no history of voice disorders, and had no systemic and neurological disorders. The study group (n = 9) was involved in the vocal training program. The control group (n = 9) has not received any training. During the program, 12 sessions of lectures and voice exercises were given to all participants of the study group for a period of 12 weeks. The sessions were planned to last for a duration of 30–45 minutes. Participants’ knowledge of vocal health was assessed using a questionnaire that was developed in the present study and a multidimensional voice assessment protocol including acoustic analyses and audio-perceptual evaluation has been applied.ResultsWithin-group comparisons indicated a significant increase in the study group participants’ knowledge of vocal hygiene after training (P = 0.011). Similarly, the study group outperformed the control group in the vocal mechanism knowledge (P = 0.027). Multidimensional Voice Profile findings revealed that vocal qualities of the control group deteriorated, whereas no alterations were found in the study group. Audio-perceptual analysis conducted through the Consensus Auditory-Perceptual Evaluation of Voice did not introduce significant changes in the control group in overall severity and roughness parameters, these values were found significantly improved for the study group.ConclusionIt can be concluded that the Holistic Vocal Training Program designed in the present study is effective for preserving theatre students’ vocal health and voice quality. It is important for future studies to search the long-term effects. 相似文献
11.
J. E. Koster E. D. Davis C. R. Gould D. G. Haase N. R. Roberson L. W. Seagondollar 《Hyperfine Interactions》1992,75(1-4):165-172
We describe a search for the time reversal non-invariant five-fold correlation (s·Ixk)(I·k) in the scattering of 2 MeV polarized neutrons from an aligned165Ho target. Here s is the neutron spin,I is the target spin, andk is the neutron momentum vector. Differences in transmission were sought when s was reversed. The target was a single crystal
of holmium, cryogenically aligned with a specially built dilution refrigerator. Rotating the target axis of alignment while
cold permits the parity-even, five-fold correlation to be identified among other spin-dependent correlations in the forward
elastic scattering amplitude. An analyzing power was found to be (1±6)×10−4, consistent with time reversal invariance.We obtain a bound of 5×10−3 for αT, the ratio of T-odd to T-even couplings in the effective nucleon-nucleon interaction. 相似文献
12.
Pulsed-laser ablation approaches are being developed for the growth of oxide thin films as versatile platform for advanced applications. Semiconducting SnO 2 thin film is of fundamental importance in the advancement of microdevices. In this review, SnO 2 thin films of various microstructures have been made using the pulsed-laser deposition method. The microstructural aspects include tetragonal, porous, and orthorhombic structure characteristics. The quantum-dots and dynamic simulations of SnO 2 nanocrystals have blossomed into a submonolayer regime devoted to the nucleation and growth for these functional films. SnO 2 thin films with some of the microstructural features may have great implications for the development of novel prototype gas sensors and transparent conduction electrodes. 相似文献
13.
《光谱学快报》2013,46(3):245-262
Abstract The goal of this paper is to illustrate college students' levels of sophistication of their spectroscopic representations (SRs). For example, a photon is drawn as a wavy line, which might be used to enhance their atomic models (AMs). Study 1 was a quantitative study in which 70 students, enrolled in first semester general chemistry, drew or described their own model of the atom. Despite the fact that they had just completed a unit on atomic structure, only 30.6% of these students were classified as having a good understanding of the Bohr AM. Most of these students, 93.8%, incorporated SRs into their models. Conversely, only 41.2% of those who had a moderate AM understanding and only 5% of those with a poor AM understanding used SR in their AMs. Study 2 was a qualitative study in which 10 volunteers, enrolled in the same course but during a different semester, interacted with a multimedia instructional package and with a tutor. Interviews with two students were selected for in‐depth analyses. Each one enhanced their own AM by adding dynamic SR to their original AMs. 相似文献
14.
ABSTRACTParticle in cell simulation was applied to fit the measurements of protons and ions acceleration obtained using an fs laser pulse irradiating a thin foil in target-normal-sheath-acceleration regime. The simulation code calculates the maximum electrical field generated in the rear side of the target driving the forward ions acceleration. The electron density versus time and space, and the plasma temperatures are evaluated using a medium contrast laser at an intensity of about 1019?Wcm?2. Proton acceleration above 10?MeV was experimentally measured using SiC detectors connected in time-of-flight configuration. A comparison between theoretical aspects and experimental data is reported and discussed. 相似文献
15.
Chen Guo-xin P.P. Ong 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,6(2):153-156
Relativistic distorted-wave method was used to calculate the electron impact excitation collision strengths for transitions
2
s2
1
S0-2
s
2
p
3
P1 of Be-like isoelectronic ions. The target states were described, respectively, by 10-level, 46-level and 133-level MCDF configuration-expansion.
The relativistic continuum orbitals were calculated in the potential field of frozen target-ion charge distribution with semi-classical
exchange potential. The influence of the target states on this collision process along the isoelectronic sequence was investigated
in the above three MCDF configuration-expansion modes. It was found that the configurations in the n
=3 and the n
=4 complexes have great influence on both the high and the low Z ions but the influence is relatively small for intermediate Z ions. The latter phenomenon was attributed to competition between opposing correlation and relativistic effects on the collision
strengths.
Received: 25 February 1998 / Received in final form: 18 June 1998 相似文献
16.
A study is reported of the conductivity of CdF2 semiconductor crystals doped by indium and gallium donor impurities and residing in a semi-isolated state. The latter results
from self-compensation of the impurities, in the course of which one half of them creates two-electron DX centers, and the second is ionized. Photo-and thermostimulated depolarization of these crystals has been studied. It was
shown that the observed polarization/depolarization phenomena have a nonlocal nature and are due to the charges present in
these crystals changing their positions. These changes may be formally considered as charge displacement to macroscopic distances
considerably in excess of the interatomic ones. The mechanisms responsible for these phenomena are discussed.
Fiz. Tverd. Tela (St. Petersburg) 41, 1575–1581 (September 1999) 相似文献
17.
In this study the model suggested by Sugiyama has been developed and applied for the calculation of the stopping powers for nonrelativistic heavy ions in various target materials. Sugiyama's model has been expanded to low and high energy regions in our work. Analytical expressions are obtained in the modified BB stopping power formula for the effective charge and effective mean excitation energies. In the modified LSS formula, a quasi-molecule criterion has been applied to both the projectiles and the target atoms. Electronic excitation contribution, S e0, and quasi-molecule contribution, S ei , to stopping power were found for a wide energy region. It is observed that in intermediate energy region both contributions have maxima. The stopping power due to excitation-ionization in the intermediate and higher energy region is found to be dominant, whereas quasi-molecule contribution is dominant in the lower energy region. The calculated results of stopping power are in good agreement with experimental data for various ions and targets within a few percent in a wide projectile energy range. 相似文献
18.
R.?Wilfinger J.?Lettry the EURISOL?Task Workgroup 《The European physical journal. Special topics》2007,150(1):379-382
EURISOL foil-targets have to withstand a primary proton
beam of 1 GeV kinetic energy and up to 100 μA
beam current. These foil targets will be based on previous
high-power target concepts, i.e. the RIST target [J.R.J. Bennett et al.,
Nucl. Instrum. Meth. Phys. Res. B 126, 117 (1997)]
or high power targets used at
TRIUMF [P. Bricault et al.,
Nucl. Instrum. Meth. Phys. Res. B 204, 319 (2003), M. Dombsky et al.,
Nucl. Instrum. Meth. Phys. Res. B 204, 191 (2003)].
A single target unit is capable of dissipating up to 25 kW,
hence, several target units can be merged together by individual
transfer lines to one common ion source. The single target units
will be irradiated by a proton beam in a time sharing mode to
distribute the primary proton beam current to the individual
target units. In this feasibility study the necessary properties
of high-power foil targets are discussed and the requirements to
design a foil target according to the proton beam parameters
[CITE] for the future EURISOL facility
are given. 相似文献
19.
N. Stevanović D. Nikezić 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(3):397-406
Collision of swift ions with atoms was considered in this paper. The
projectile and target atoms were modeled as assemblies of quantum
oscillators and it was assumed that both, target and projectile could be
excited or ionized, without charge exchange. The model presented here is an
extension of the one given by Sigmund and Haagerup [Phys. Rev. A 34, 892 (1986)]. The number of electrons bound to the projectile, as a function of the projectile velocity,
was used from Cabrera-Trujillo et al. [Phys. Rev. A 55, 2864 (1997)]. Contributions to energy loss from excitation of the projectile and targets were separately considered. It
has been found that projectile excitation contributes up to 20% to the
total energy loss in the lower energy region. Comparisons with other
authors, including SRIM 2003, are also given and good agreement was found. 相似文献
20.
M. Jochum H.-G. Unruh 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,5(2):163-168
Dielectric and Raman spectroscopic measurements have been performed to investigate the ferroelectric phase transition in . Single crystals were grown by the zone melting method. The frequency dependence of the dielectric permittivity from 1 MHz
to 1 GHz has been studied in a temperature range between 265 and 285 K. A Debye like dielectric dispersion was found, showing
a critical slowing down around K. Polarized Raman spectra have been taken between 220 and 310 K. Two softening modes have been found, one of A- and another one of B
/
B
g-symmetry. The phase transition mechanism in can be classified as partially order-disorder and partially displacive, confirming former structural results. It resembles
strongly that of monoclinic .
Received: 7 April 1998 / Revised: 5 June 1998 / Accepted: 16 June
1998 相似文献