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J.W. Maas E. Somorjai H.D. Graber C.A. Van Den Wijngaart C. Van Der Leun P.M. Endt 《Nuclear Physics A》1978,301(2):213-236
Particle energies have been measured for resonances in the 27Al(p, γ)28Si and 24Mg(α, γ)28Si reactions with an accuracy of 0.5 × 10?4 and 1 × 10?4, respectively. The Ep = 991.88 ± 0.04 keV27Al(p, γ)28Si resonance served as calibration point. From these data the Q-value of the reaction 27Al(p, α)24Mg has been determined as 1600.14 ± 0.21 keV. Excitation energies of 28Si levels have been measured with the 27Al(p, γ)28Si reaction; the reaction energy is Q = 11584.5 ± 0.4 keV.Of 33 resonances observed in the 24Mg(α, γ)28Si reaction (Eα = 1.5–3.8 MeV), energies, strengths and γ-ray decay have been measured; five of these resonances had not been reported previously. The γ-ray angular distribution measurements at three resonances yield the resonance Jπ values and the mixing ratios of the strongest transitions involved in the decay. The 10.38 MeV level has Jπ = 3+, T = 1. The arguments on which T-assignments can be based are critically reviewed. These arguments are used to assign T = 1 character to 19 states of 28Si. 相似文献
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H.F.R. Arciszewski E.A. Bakkum C.P.M. Van Engelen P.M. Endt R. Kamermans 《Nuclear Physics A》1984,430(1):234-248
Angular distributions have been measured for the 25Mg(d, p)26Mg reaction at 13 MeV leading to excited states between Ex = 0 and 8 MeV. Experimental cross sections are compared with DWBA calculations and extended shell-model calculations in the full sd shell. Spin and parity restrictions are obtained for several levels in the region Ex = 6?;8 MeV. Spectroseopic factors for transitions to the lowest four positive-parity states of each spin are well reproduced by the shell-model calculations; however, in mixed configurations the largest component is systematically underestimated by the shell model. Only 60% of the strength for transfer is observed. 相似文献
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C.?Solazzo D.?ErhardtEmail author F.?Marte D.?von Endt C.?Tumosa 《Applied Physics A: Materials Science & Processing》2004,79(2):247-252
In the fall of 2001, anthrax-contaminated letters were sent to public figures in the United States. Chemical and radiation treatments were employed to decontaminate exposed buildings, objects, and materials. These treatments are effective, but potentially damaging to exposed objects and materials. The recommended surface chemical treatments include solutions, gels, and foams of oxidizing agents such as peroxides or chlorine bleaching agents. Such oxidizing agents are effective against a wide range of hazardous chemical and biological agents. Knowing how these reagents affect various substrates would help to anticipate and to minimize any potential damage. We are examining the effects on typical museum materials of reagents likely to be used, including hydrogen peroxide, sodium hypochlorite, and potassium peroxymonosulfate. Results so far show significant changes in a number of materials. Surface corrosion was observed on metals such as copper, silver, iron, and brass. Color changes occurred with at least one reagent in about one-fourth of the dyed fabric swatches tested, and about half of the inks. Samples of aged yellowed paper are bleached. Effects varied with both the substrate and the tested reagent. The observed changes were generally less drastic than might have been expected. Enough materials were affected, though, to preclude the use of these reagents on museum objects unless no less drastic alternative is available. It appears that many objects of lesser intrinsic value can be treated without severe loss of properties or usefulness. For example, most documents should remain legible if the appropriate reagent is used. This work will provide a basis for determining which treatment is most appropriate for a specific situation and what consequences are to be expected from other treatments. PACS 81.65.Mq; 81.70.Jb; 82.30.Lp 相似文献
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J. F. Shriner Jr. E. G. Bilpuch P. M. Endt G. E. Mitchell 《Zeitschrift für Physik A Hadrons and Nuclei》1990,335(4):393-400
The fluctuation properties of the energy levels of26Al from the ground state to excitation energies of about 8 MeV have been examined. Several statistics have been employed, and particular attention has been given to the suitability of these statistics for small sample sizes. The results show, for a variety of states, behavior intermediate between GOE and Poisson but apparently favoring GOE. The results are consistent with the fluctuations' being independent of isospin. 相似文献
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A recent review of the strengths of about 600 γ-ray transitions between bound states in the A = 21–44 region is extended in the present paper by including (i) the A<21 region, (ii) recent data on the A = 21–44 region, (iii) E0 transitions, (iv) magnetic transitions of which the (experimentally unknown) mixing ratio can be assumed to be negligibly small. The present addition concerns 350 transitions. Interesting new groups are the isovector E2 transitions (9 cases), and the isoscalar M2 transitions (7 cases). For magnetic transitions, the dependence of isospin retardation on multipolarity is stronger than expected theoretically. Recommended upper limits are presented for the 11 groups with reasonably good statistics. Because the strengths in the A<21 and A = 21–44 regions differ but little, the same upper limits can be used for the two regions. 相似文献
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Marcelo Fernando Kern Simone de Faria Maraschin Débora Vom Endt Augusto Schrank Marilene Henning Vainstein Giancarlo Pasquali 《Applied biochemistry and biotechnology》2010,160(7):1933-1946
The chit1 gene from the entomopathogenic fungus Metarhizium anisopliae, encoding the endochitinase CHIT42, was placed under the control of the CaMV 35S promoter, and the resulting construct was
transferred to tobacco. Seventeen kanamycin-resistant transgenic lines were recovered, and the presence of the transgene was
confirmed by polymerase chain reactions and Southern blot hybridization. The number of chit1 copies was determined to be varying from one to four. Copy number had observable effects neither on plant growth nor development.
Substantial heterogeneity concerning production of the recombinant chitinase, and both general and specific chitinolytic activities
were detected in leaf extracts from primary transformants. The highest chitinase activities were found in plants harboring
two copies of chit1 inserts at different loci. Progeny derived from self-pollination of the primary transgenics revealed a stable inheritance
pattern, with transgene segregation following a mendelian dihybrid ratio. Two selected plants expressing high levels of CHIT42
were consistently resistant to the soilborne pathogen Rhizoctonia solani, suggesting a direct relationship between enzyme activity and reduction of foliar area affected by fungal lesions. To date,
this is the first report of resistance to fungal attack in plants mediated by a recombinant chitinase from an entomopathogenic
and acaricide fungus. 相似文献
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The γ-radiation produced by thermal neutron capture in a natural Na sample has been investigated. Of the 158 γ-rays ascribed to the 23Na(n, γ)24Na reaction, 143 have been placed in a 24Na decay scheme accounting for 100(2) % of the total primary strength. The reaction Q-value amounts to 6959.42 ± 0.08 keV. The data resulted in spin assignments for four and spin restrictions for six levels.The circular polarization of 14 γ-rays from the capture of polarized neutrons has been measured. The contribution of the Jπ = 2+ channel in thermal capture was determined to be below 5 %. 相似文献
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The γ-decay of 60 and the strengths of 51 26Mg(p, γ)27Al resonances were studied for Ep < 2.20 MeV. The energies of 32 and the γ-decay of 54 bound levels were determined. Spin and parity assignments were made to the bound states at Ex = 4.81, 5.44, 6.61, 6.78, 7.68 and 7.86 MeV, respectively. Spin assignments and were made to the bound levels at Einx = 5.55 and 6.08 MeV, respectively. For other levels spin and parity limitations were set. Lifetimes or lifetime upper limits of 19 bound levels were measured by means of the DSA technique. The spins and/or parities of 15 resonances were unambiguously determined from γ-ray angular distributions and strengths. 相似文献