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61.
J. Dilling G. Audi D. Beck G. Bollen F. Herfurth A. Kellerbauer H.-J. Kluge D. Lunney R.B. Moore C. Scheidenberger S. Schwarz G. Sikler J. Szerypo 《Hyperfine Interactions》2001,132(1-4):329-333
The masses of the xenon isotopes with 114≤A≤123 were directly measured for the first time. The experiments were carried out at the ISOLTRAP triple trap spectrometer
at the on-line mass separator ISOLDE/CERN. A mass resolving power of the Penning trap spectrometer of m/Δm≈500 000 was chosen and an accuracy of δm≈12keV for all investigated Xe isotopes was achieved. An atomic mass evaluation was performed and the results of this adjustment
are compared with theoretical predictions. The new results for the xenon isotopes and their effects on neighboring nuclides
are discussed within the two-neutron separation energy picture.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
62.
Organometallic compounds and surfactants constitute a potential threat to the environment. For that reason we have embarked on a study of their joint action on membranes. Model lecithin liposome membranes were modified with the cationic surfactant trimethyldodecylammonium bromide or the anionic surfactant sodium dodecylsulfonate, and the effect of tripropyltin chloride on the process of calcium (Ca2+) and praseodymium (Pr3+) desorption from the liposome membrane was studied. Kinetic constants for the process of Ca2+ ion desorption from lecithin liposome membranes were determined using the radiotracer method. The percentage of Pr3+ ion desorption from liposome membranes was measured by the 1H NMR method. Trimethyltin, triethyltin and tripropyltin alone caused increased Ca2+ and Pr3+ desorption from liposome membranes with increasing concentration of the compounds and alkyl chain length. For both the processes studied, a cationic surfactant brought about a lower effectiveness of tripropyltin and an anionic surfactant resulted in a higher effectiveness. The effect observed can be explained by changes in the surface charge of the membrane, induced by the surfactant modifiers and by the concomitant change in the partition coefficient of the organotin. The results obtained indicate a protective or harmful joint action of the surfactants used with tripropyltin on membranes. © 1997 John Wiley & Sons, Ltd. 相似文献
63.
A simple and fast synthesis of radioactive methylmercury is presented. It is based on the methylation of inorganic 203Hg(II) by methylcobalamin and isolation of resulting CH3203Hg(II) in a single extraction step. Time required is less than 4 hours and the final yield is ⩾90%. © 1997 John Wiley & Sons, Ltd. 相似文献
64.
65.
Secondary ion mass spectrometry (SIMS) was optimised for characterisation of uranium- and plutonium-containing particles
in soils, swipes and forensic samples. This was done by analysing in-house produced spherical UO2-particles. Screening techniques as α-autoradiography together with SIMS analysis were employed to detect UO2-particles in a soil sample from Chernobyl.
The use of SIMS was exploited for the identification of uranium- and plutonium-containing particles and for the determination
of their isotopic composition. The particles collected on swipe samples were transferred to a special adhesive support for
the analysis by SIMS. Particles containing highly enriched uranium with diameters up to 10 μm were also detected in a forensic
sample. For the measurements of the isotopic ratios a mass resolution of 1000 was used. At this resolution flat-top peaks
were obtained which greatly improve the accuracy of the measurement. The isotopic composition of the particles was measured
with a typical accuracy and precision of 0.5%. Statistically meaningful results can be obtained, for instance, from a specimen
containing as few as 1010 atoms/μm3 of uranium in particles of UO2 weighing a few picograms. 相似文献
66.
S. F. Boulyga A. I. Kievitskaja M. K. Kievets E. M. Lomonosova I. V. Zhuk O. I. Yaroshevich V. P. Perelygin R. Petrova R. Brandt P. Vater 《Radiation measurements》1999,31(1-6):191-196
Nuclear track radiography was applied to identify aerosol “hot” particles which contain elements of nuclear fuel and fallout after Chernobyl NPP accident. For the determination of the content of transuranium elements in radioactive aerosols the measurement of the -activity of “hot” particles by SSNTD was used in this work, as well as radiography of fission fragments formed as a result of the reactions (n,f) and (γ,f) in the irradiation of aerosol filters by thermal neutrons and high energy gamma quanta. The technique allowed the sizes and alpha-activity of “hot” particles to be determined without extracting them from the filter, as well as the determination of the uranium content and its enrichment by 235U, 239Pu and 241Pu isotopes. Sensitivity of determination of alpha activity by fission method is 5×10−6 Bq per particle. The software for the system of image analysis was created. It ensured the identification of track clusters on an optical image of the SSNTD surface obtained through a video camera and the determination of size and activity of “hot” particles. 相似文献
67.
段芳芳 杨彦云 庞丹阳 胡碧涛 王建松 王康 杨过 Valdir Guimar?es 马朋 许世伟 刘星泉 马军兵 白真 胡强 金树亚 孙欣欣 姚佳盛 齐航凯 孙志宇 《中国物理C(英文版)》2020,(2):72-79
Elastic scattering of 10Be on a 208Pb target was measured at ELab=127 MeV,which corresponds to three times the Coulomb barrier.The secondary 10Be beam was produced at the Radioactive Ion Beam Line in Lanzhou of the Heavy-Ion Research Facility in Lanzhou.The angular distribution of elastic scattering in the 10 Be+208Pb system shows a typical Fresnel diffraction peak.Optical model analysis of the angular distribution was performed using the Woods-Saxon,double-folding and global potentials.With the global potential,different density distributions were used.The results indicate that different density distributions for the projectile induce distinct effects in the angular distribution. 相似文献
68.
Target-ion source unit ionization efficiency measurement by a method of stable ion beam implantation
V. N. Panteleev A. E. Barzakh D. V. Fedorov P. L. Molkanov F. V. Moroz S. Yu. Orlov Yu. M. Volkov 《The European physical journal. Special topics》2007,150(1):301-302
At the IRIS facility a rather precise method of the
target-ion source unit ionization efficiency measurement has been
developed. The method exploits an off-line
mass-separator for the implantation of the ion beams of selected stable isotopes into a tantalum foil placed inside a Faraday
cup
in the focal plane of the mass-separator. After the
implantation of the required amount of the investigated species, tantalum foil has been inserted into
the volume of the target-ion source unit prepared for the on-line utilization at the IRIS
on-line separator. The first tests have ensured the ionization efficiency values
(90±10)% for Rb and (85±10)% for Cs in the empty combined
target-ion source unit, which was
used as a reference one. For the target-ion source unit with UC target material inside the measured value of the ionization
efficiency of Rb was (52±20)%. 相似文献
69.
D. J. Morrissey 《The European physical journal. Special topics》2007,150(1):365-366
The NSCL gas cell and quadrupole ion-guide system has been
used to study the thermalization of fast nuclear reaction products
in a buffer gas. The fraction of radioactive ions that can be
extracted from the gas cell is dramatically suppressed by space
charge created by the stopping ions. The results of a review of the
ion yields from the NSCL and from other gas cells from the
literature with different sizes and different incident particle
energies shows an overall consistency with a dramatic decline in
extraction efficiency at high ionization rates. 相似文献
70.
N. L. Achouri F. de Oliveira Santos M. Lewitowicz B. Blank J. Äystö G. Canchel S. Czajkowski P. Dendooven A. Emsallem J. Giovinazzo N. Guillet A. Jokinen A. M. Laird C. Longour K. Peräjärvi N. Smirnova M. Stanoiu J. -C. Thomas 《The European Physical Journal A - Hadrons and Nuclei》2006,27(3):287-300
In an experiment performed at the LISE3 facility of GANIL, we studied the decay of 22Al produced by the fragmentation of a 36Ar primary beam. A β-decay half-life of T1/2 = 91.1±0.5ms was measured. The β-delayed one- and two-proton emission as well as β-α and β-delayed γ-decays were measured
and allowed us to establish a partial decay scheme for this nucleus. New levels were determined in the daughter nucleus 22Mg. The comparison with model calculations strongly favours a spin-parity of Iπ = 4+ for the ground state of 22Al. 相似文献