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91.
S. L. Olsen 《Zeitschrift fur Physik C Particles and Fields》1982,13(3):215-217
The Chou-Yang model forpp elastic scattering, modified to include the effect of coupled inelastic channels, is used to fit recent data in the region of the dip, i.e., 1.0≦|t|≦2.0 (GeV/c)2 for incident momenta ranging from 35 to 250 GeV/c. Good quantitative agreement is found for an inelastic coupling which is predominantly real, as compared to the mostly imaginary elastic coupling. Implications for dips at highert, which are predicted by the model but as yet not observed experimentally, are discussed. 相似文献
92.
Douglas A. Olsen A. Jean Osteraas 《Journal of polymer science. Part A, Polymer chemistry》1969,7(7):1921-1926
Previous work has shown that atomic sulfur irreversibility modifies polyethylene, presumably through an insertion reaction into carbon—hydrogen bonds with formation of surface thiol groups. The thiol groups were then oxidized to sulfonic acid surface groups, which were further reacted chemically as shown by wettability measurements. In this work the thiol group was bypassed and the surface sulfonic acid groups were obtained by exposing the polyethylene surface directly to fuming sulfuric acid. The sulfonic acid groups were reacted further. Critical surface tension values identical with those in the previous work with atomic sulfur were obtained, thus substantiating the previous work. 相似文献
93.
Four equidistant peaks are observed below the Kα1,2 line in the X-ray spectra of Na, Al, Si, SiO2, Ca, Sc and Ti, produced by oxygen bombardment. With much weaker intensity, these lines are also seen in proton excitation. The lines are interpreted to be due to the excitation of one or more volume plasmons in the target material by the Kα1,2 X-ray decay. 相似文献
94.
W. Seth Horne Dr. Christian A. Olsen Dr. John M. Beierle Ana Montero Dr. M. Reza Ghadiri Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(26):4718-4724
Fooling enzymes with mock amides : Analogues of apicidin, a cyclic‐tetrapeptide inhibitor of histone deacetylase (HDAC), were designed with a 1,4‐ or 1,5‐disubstituted 1,2,3‐triazole in place of a backbone amide bond to fix the bond in question in either a trans‐like or a cis‐like configuration. Thus, the binding affinity of distinct peptide conformations (see picture) could be probed. One analogue proved in some cases to be superior to apicidin as an HDAC inhibitor.
95.
Ananthachari Srinivasan Aldean J. Kolar Richard K. Olsen 《Journal of heterocyclic chemistry》1981,18(8):1545-1548
The reaction of several geminal dithiols with 3,6-dibromo-1,4-dimethyl-2,5-piperazinedione gave in good yields piperazinedione derivatives substituted at the 3,6-position with a geminal dithiol-bridging group. These sulfur-bridged piperazinediones formally represent derivatives of the 2,4-dithia-6,8-diaza-7,9-dioxobicyclo[3.2.2]nonane ring system. Attempts to transform these sulfur-bridged piperazinediones to 3,6-epidithiopiperazinediones by removal of the bridging group common to the sulfur functionality were unsuccessful. Studies also are reported of addition of thioacetic acid to 3,6-dimethylene-2,5-piperazinedione to give 3,6-diacetylthio-3,6-dimethyl-2,5-piperazinedione. Conversion of the 3,6-diacetylthio derivative to the epithiopiperazinedione ring system yielded a mixture of epimono- and epidithiopiperazinediones. 相似文献
96.
Des-N-tetramethyltriostin A (1), a known DNA-intercalation agent, has been synthesized from tetra- and octapeptide intermediates that have Z-d-serine at the C-terminal position. The procedure thus allows the fragment coupling and cyclization reactions leading to the synthesis of the title compound to occur without racemization at the C-terminal amino acid. Esterification of Boc-Val-OH with the p-bromophenacyl ester of Z-d-serine provided didepsipeptide Z-d-Ser(Boc-Val)-OBpa (4). Stepwise addition of the requisite amino acids provided tetradepsipeptide Z-d-Ser[Boc-Ala-Cys(Acm)-Val]-OBpa (6). Fragment coupling of the respective C- and N-deprotected tetradepsipeptides 7 and 8, derived from 6, furnished linear octadepsipeptide 9, which upon cyclization and disulfide formation gave the bicyclic octadepsipeptide 11, a known synthetic precursor to 1. The degree of racemization incurred in the alanine and valine residues of selected depsipeptides was measured and the results compared with those obtained in previous studies. It was concluded that alanine, perhaps because of sequence effects, undergoes a degree of racemization (4–10%) during hydrolysis of tetradepsipeptide 6 and octadepsipeptide 9. 相似文献
97.
The interaction between solitary wave solutions to a double sine-Gordon equation is examined numerically. Depending on the velocity, formation of breather-like modes or quasi solitonic behaviour are observed when a 2δ-kink interact with a 2π-antikink. As a result of collision between a (2π-2δ)-kink and a (2π-2δ)-antikink two 2δ-kink-antikink pairs always appear. 相似文献
98.
99.
D.A. Garbutt R.W. Rusack Ion Siotis D. Gross D. Nitz S. Olsen K. Abe R. Bomberowitz K. Cohen P. Goldhagen F. Sannes D. Saroff J. Willison 《Physics letters. [Part B]》1977,67(3):355-357
The inclusive production of π+, π?, K+, K?, p and for protons incident on carbon and tungsten targets was studied at the Internal Target Area of the Fermilab. We assume an Aα dependence for the inclusive cross sections and report here on the variation of α with incident momentum, transverse momentum and particle species. 相似文献
100.