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161.
A. Görgen E. Clément A. Chatillon A. Dewald W. Korten Y. Le Coz N. Mărginean B. Melon R. Menegazzo O. Möller Ch. Theisen D. Tonev C. A. Ur K. O. Zell 《The European Physical Journal A - Hadrons and Nuclei》2005,26(2):153-157
Lifetimes of excited states in the ground-state bands of 74Kr and 76Kr were measured using the recoil-distance Doppler-shift and the differential decay curve methods. The states were populated
in the 40Ca(40Ca, α2p) and 40Ca(40Ca, 4p) reactions. Gamma rays were detected with the GASP array which was coupled to the Cologne Plunger device. The results resolve
discrepancies between earlier lifetime measurements and a recent Coulomb excitation experiment. Experimental transition rates
are compared to theoretical calculations. The results support a strong mixing between prolate and oblate configurations for
the low-spin states, and represent an important basis for the interpretation and understanding of the shape coexistence phenomenon
in this mass region. 相似文献
162.
Ravi P. Agarwal Ghaus Ur Rahman Muhsina 《Mathematical Methods in the Applied Sciences》2023,46(2):2801-2839
In this article, we formulate fractional differential inclusion of pantograph type (IFDIP), incorporating impulsive behavior of the solution. The boundary conditions taken into account are nonlocal in nature. We will consider the convex problem and prove the Filippov–Wazewski-type theorem. Moreover, existence of solution, uniqueness of a solution, and the topological properties of the solution's set will be examined for the problem under consideration. In the second part, the study will be confined to the second-order impulsive fractional differential equation of pantograph type. For certain geometric characteristics of the solution's set, Aronszajn–Browder–Gupta-type results will be explored for the newly introduced differential equation. Also, it will prove the existence of solution for the first-order fractional differential equation of pantograph type having impulsive behavior of the solution. 相似文献
163.
A density functional theory based on the weighted density has been developed to investigate the depletion interactions between two colloids immersed in a bath of the binary polymer mixtures, where the colloids are modeled as hard spheres and the polymers as freely jointed tangent hard-sphere chain mixtures. The theoretical calculations for the depletion forces between two colloids induced by the polymer are in good agreement with the computer simulations. The effects of polymer packing fraction, degree of polymerization, polymer/polymer size ratio, colloid/polymer size ratio on the depletion interactions, and colloid-colloid second virial coefficient B2 due to polymer-mediated interactions have been studied. With increasing the polymer packing fraction, the depletion interaction becomes more long ranged and the attractive interaction near the colloid becomes deeper. The effect of degree polymerization shows that the long chain gives a more stable dispersion for colloids rather than the short chain. The strong effective colloid-colloid attraction appears for the large colloid/polymer and polymer/polymer size ratio. The location of maximum repulsion Rmax is found to appear Rmax approximately sigmac+Rg2 for the low polymer packing fraction and this is shifted to smaller separation Rmax approximately sigmac+sigmap2 with increasing the polymer packing fraction, where sigmap2 and Rg2 are the small-particle diameter and the radius of gyration of the polymer with the small-particle diameter, respectively. 相似文献
164.
Ribeiro Guevara S Zizek S Repinc U Pérez Catán S Jaćimović R Horvat M 《Analytical and bioanalytical chemistry》2007,387(6):2185-2197
Mercury tracers are powerful tools that can be used to study mercury transformations in environmental systems, particularly
mercury methylation, demethylation and reduction in sediments and water. However, mercury transformation studies using tracers
can be subject to error, especially when used to assess methylation potential. The organic mercury extracted can be as low
as 0.01% of the endogenous labeled mercury, and artefacts and contamination present during methylmercury (MeHg) extraction
processes can cause interference. Solvent extraction methods based on the use of either KBr/H2SO4 or HCl were evaluated in freshwater sediments using 197Hg radiotracer. Values obtained for the 197Hg tracer in the organic phase were up to 25-fold higher when HCl was used, which is due to the coextraction of 197Hg2+ into the organic phase during MeHg extraction. Evaluations of the production of MeHg gave similar results with both MeHg
extraction procedures, but due to the higher Hg2+ contamination of the controls, the uncertainty in the determination was higher when HCl was used. The Hg2+ contamination of controls in the HCl extraction method showed a nonlinear correlation with the humic acid content of sediment
pore water. Therefore, use of the KBr/H2SO4 method is recommended, since it is free from these interferences. 197Hg radiotracer (T
1/2 = 2.673 d) has a production rate that is about 50 times higher than that of 203Hg (T
1/2 = 46.595 d), the most frequently used mercury radiotracer. Hence it is possible to obtain a similar level of performance
to 203Hg when it is used it in short-term experiments and produced by the irradiation of 196Hg with thermal neutrons, using mercury targets with the natural isotopic composition. However, if the 0.15% natural abundance
of the 196Hg isotope is increased, the specific activity of the 197Hg tracer can be significantly improved. In the present work, 197Hg tracer was produced from mercury 51.58% enriched in the 196Hg isotope, and a 340-fold increase in specific activity with respect to natural mercury targets was obtained. When this high
specific activity tracer is employed, mercury methylation and reduction experiments with minimum mercury additions are feasible.
Tracer recovery in methylation experiments (associated with Me197Hg production from 197Hg2+ spike, but also with Hg2+ contamination and Me197Hg artefacts) with marine sediments was about 0.005% g−1 WS (WS: wet sediment) after 20 h incubation with mercury additions of 0.05 ng g−1 WS, which is far below natural mercury levels. In this case, the amount of Hg2+ reduced to Hg0 (expressed as the percent 197Hg0 recovered with respect to the 197Hg2+ added) varied from 0.13 to 1.6% g−1 WS. Me197Hg production from 197Hg2+ spike after 20 h of incubation of freshwater sediment ranged from 0.02 to 0.13% g−1 WS with mercury additions of 2.5 ng g−1 WS, which is also far below natural levels. 197Hg0 recoveries were low, 0.0058 ± 0.0013% g−1 WS, but showed good reproducibility in five replicates. Me197Hg production from 197Hg2+ spiked in freshwater samples ranged from 0.1 to 0.3% over a period of three days with mercury additions of 10 ng L−1. A detection limit of 0.05% for Me197Hg production from 197Hg2+ spike was obtained in seawater in a 25 h incubation experiment with mercury additions of 12 ng L−1. 相似文献
165.
Alkyl glycosides were used as templating surfactants in the sol–gel processing of thin silica films. The sols were made from a prehydrolyzed silicate solution with the addition of a glucoside or a maltoside surfactant. The sol–gel–xerogel transitions and the silica–sugar interactions were studied by IR ATR spectroscopy. The siloxane condensation rate in the silica/glycoside sol was considerably reduced compared to a pure silica system due to hydrogen bonding interactions between the silanols and the sugar head groups. Thin films were deposited on silicon wafers and characterized by IR transmission, X-ray diffraction and TEM analysis. The size of the sugar head group had a large influence on the type of the mesophases formed. The use of the glucoside surfactant only resulted in temperature unstable lamellar phases, whereas the maltosides at low concentrations assembled in curved mesophases that were stable to template removal by extraction or calcination. 相似文献
166.
D. Montanari S. Leoni D. Mengoni G. Benzoni N. Blasi G. Bocchi P.F. Bortignon A. Bracco F. Camera G. Colò A. Corsi F.C.L. Crespi B. Million R. Nicolini O. Wieland J.J. Valiente-Dobon L. Corradi G. de Angelis F. Della Vedova E. Fioretto A. Gadea D.R. Napoli R. Orlandi F. Recchia E. Sahin R. Silvestri A.M. Stefanini R.P. Singh S. Szilner D. Bazzacco E. Farnea R. Menegazzo A. Gottardo S.M. Lenzi S. Lunardi G. Montagnoli F. Scarlassara C. Ur G. Lo Bianco A. Zucchiatti M. Kmiecik A. Maj W. Meczynski A. Dewald Th. Pissulla G. Pollarolo 《Physics letters. [Part B]》2011
167.
In this paper, the approximate solutions to the eighth-order boundary-value problems are presented using the reproducing kernel space method. The procedure is applied on both linear and nonlinear problems. Searching least value (SLV) method is investigated for nonlinear boundary value problems. The argument is based on the reproducing kernel space $W_{2}^{9}[a,b]$ . The approach provides the solution in the form of a convergent series with easily computable components. Analytical results are given for several examples to illustrate the implementation and efficiency of the method. A comparison of the results obtained by the present method with results obtained by other methods reveals that the present method is more effective and convenient. 相似文献
168.
A. Lopez-Martens T. Døssing T. L. Khoo B. Herskind T. Lauristen M. Matsuo K. Yoshida A. Korichi F. Hannachi I. Ahmad H. Amro G. de Angelis D. Bazzacco C. Beausang E. Bouchez P. Bringel I. J. Calderin M. P. Carpenter S. M. Fischer G. Hackman K. Hauschild H. Hübel A. Hurstel R. V. F. Janssens F. G. Kondev W. Korten T. Kröll Y. Le Coz N. Marginean R. Menegazzo E. Mergel D. Napoli N. Nenoff S. Neumann A. Neusser D. Nisius G. Mukherjee M. Rejmund D. Rossbach C. Rossi Alvarez C. Schück G. Schonwasser A. K. Singh Ch Theisen Ch Vieu C. Ur 《The European Physical Journal A - Hadrons and Nuclei》2003,20(1):49-53
We report on four recent results concerning the population and the decay of superdeformed states, namely the structure of excited superdeformed states in 194Hg, the search for fine structure of the last superdeformed transitions in 194Pb, the primary decay-out strength analysis in 194Hg and, as a consequence of this, the possibility of using the decay-out as a tool to study order-to-chaos properties of normally deformed states.Received: 3 December 2002, Published online: 17 February 2004PACS:
21.10.Re Collective levels - 23.20.Lv
transitions and level energies - 24.60.-k Statistical theory and fluctuations - 24.60.Lz Chaos in nuclear systems - 27.80. + w
F. Hannachi: Present address: CENBG/IN2P3, Gradignan, France.H. Amro: Present address: WNSL, Yale, USA.K. Hauschild: Present address: CSNSM/IN2P3, Orsay, France.T. Kröll: Present address: TU, Munich, Germany.M. Rejmund: Present address: GANIL, Caen, France. 相似文献
169.
Ts Venkova R. M. Lieder W. Gast D. Bazzacco G. de Angelis E. Podsvirova H. M. Jäger L. Mihailescu R. Menegazzo S. Lunardi C. Rossi Alvarez C. Ur T. Martinez M. Axiotis D. Napoli W. Urban T. Rzaca-Urban S. Frauendorf 《The European Physical Journal A - Hadrons and Nuclei》2003,18(1):1-4
High-spin states in the odd-odd nucleus 172Lu have been populated in a 170Er(7Li, 5n) reaction and the emitted
-radiation was detected with the GASP array. Two sequences of a new identical band have been observed with the transition energies in the favoured and unfavoured sequences being identical within
keV at low spins and
keV at high spins over the whole observed spin range. Aninterpretation as a pseudo-spin singlet band of
configuration is proposed. It represents the best example of a pseudo-spin singlet band in normal deformed nuclei known until now.Received: 19 February 2003, Revised: 27 March 2003, Published online: 12 August 2003PACS:
21.10.-k Properties of nuclei; nuclear energy levels - 21.10.Re Collective levels - 23.20.Lv
transitions and level energies - 27.70.+q
相似文献
170.
Th Kröll D. Bazzacco R. Venturelli B. Quintana Arnes C. A. Ur M. Bellato R. Isocrate Ch Manea R. Menegazzo P. Pavan C. Rossi Alvarez E. Farnea A. Gadea D. Rosso P. Spolaore F. Camera B. Million E. Musso A. Pullia O. Wieland G. Casati A. Geraci G. Ripamonti M. Descovich 《The European Physical Journal A - Hadrons and Nuclei》2003,20(1):205-206
The feasibility of the entire process of
-ray tracking is demonstrated experimentally for the first time. The accuracy of the results is tested by the capability for Doppler correction of
-rays emitted in flight. The resolution of the 847.8 keV (
) transition detected with the MARS detector after Coulomb excitation of a 56Fe beam could be improved from 15 keV to below 5 keV (FWHM).Received: 28 October 2002, Published online: 2 March 2004PACS:
29.30.Kv X- and gamma-ray spectroscopy - 29.40.Gx Tracking and position-sensitive detectors - 29.40.Wk Solid-state detectorsC.A. Ur: On leave from: NIPNE, Bucharest, Romania. 相似文献