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1.
Wojciech Bocian Jarosław Jaźwínski Lech Stefaniak Graham A. Webb 《Chemistry of Heterocyclic Compounds》1995,31(9):1103-1107
1H,13C,14N and15N NMR measurements are reported for four mesoionic 1-oxa-2, 3, 4-triazoles containing exocyclic nitrogenous groups. The NMR signal assignments are discussed and compared with those previously published for some corresponding oxatriazoles. The results obtained support the proposed cyclic mesoionic structures for the compounds studied. The questions of possible charge delocalization and valence tautomerism are addressed. Compound with N– H as a exocyclic group (Fig. 1) is found to be relatively unstable, this is attributed to proton migration in the corresponding non-cyclic form of this molecule.Published in Khimiya Geterotsikiicheskikh Soedinenii, No. 9, pp. 1260–1263, September, 1995. 相似文献
2.
Weir AJ Klein SR Abrams G Adolphsen CE Akerlof C Alexander JP Alvarez M Amidei D Baden AR Ballam J Barish BC Barklow T Barnett BA Bartelt J Blockus D Bonvicini G Boyarski A Boyer J Brabson B Breakstone A Brom JM Bulos F Burchat PR Burke DL Butler F Calvino F Cence RJ Chapman J Cords D Coupal DP DeStaebler HC Dorfan DE Dorfan JM Drell PS Feldman GJ Fernandez E Field RC Ford WT Fordham C Frey R Fujino D Gan KK Gidal G Gladney L Glanzman T Gold MS Goldhaber G Green A Grosse-Wiesmann P Haggerty J 《Physical review D: Particles and fields》1990,41(5):1384-1388
3.
Wu DY Hayes K Perl ML Barklow T Boyarski A Burchat PR Burke DL Dorfan JM Feldman GJ Gladney L Hanson G Hollebeek RJ Innes WR Jaros JA Karlen D Klein SR Lankford AJ Larsen RR LeClaire BW Lockyer NS Lüth V Ong RA Richter B Riles K Yelton JM Abrams G Amidei D Baden AR Boyer J Butler F Gidal G Gold MS Goldhaber G Golding L Haggerty J Herrup D Juricic I Kadyk JA Levi ME Nelson ME Rowson PC Schellman H Schmidke WB Sheldon PD Trilling GH Wood DR Schaad T 《Physical review D: Particles and fields》1990,41(7):2339-2342
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Klein SR Himel TM Abrams G Amidei D Baden AR Barklow T Boyarski AM Boyer J Burchat PR Burke DL Butler F Dorfan JM Feldman GJ Gidal G Gladney L Gold MS Goldhaber G Golding L Haggerty J Hanson G Hayes K Herrup D Hollebeek RJ Innes WR Jaros JA Juricic I Kadyk JA Karlen D Lankford AJ Larsen RR LeClaire BW Levi M Lockyer NS Lüth V Matteuzzi C Nelson ME Ong RA Perl ML Petersen A Richter B Riles K Rowson PC Schaad T Schellman H Schmidke WB Sheldon PD Trilling GH de la Vaissiere C Wood DR Yelton JM 《Physical review letters》1987,58(7):644-647
6.
Jarosław Cel 《Journal of Geometry》1995,53(1-2):28-36
It is proved for a nonempty proper subset S of a real topological linear space L that kerS ={convAz: z bdryS} and for a close connected nonconvex subset S of L that kerS ={convAz: z slncS}, where bdryS and slncS denote the sets of boundary points and strong local nonconvexity points of S, respectively, and Az = {s S: z is clearly visible from s via S}.This extends previous results and, combined with standard techniques, yields among others two Krasnosel'skii-type characterizations for the dimension of kerS in Rd in case of a nonempty proper set S with bdryS bounded and a closed connected nonconvex set S with lncS bounded.The assumption of boundedness of S turns out to be irrelevant in these criteria.Herrn Professor Dr. Wilhelm Stoll gewidmetResearch partially supported by the grant PB 2 1140 91 01 相似文献
7.
Jarosław Pykacz 《International Journal of Theoretical Physics》1994,33(7):1403-1416
A new, physically more plausible definition of a fuzzy quantum logic is proposed. It is shown that this definition coincides with the previously studied definition of a fuzzy quantum logic; therefore it defines objects which are traditional quantum logics with ordering sets of states. The new definition is expressed exclusively in terms of fuzzy set operations which are generated by connectives of multiple-valued logic studied by ukasiewicz at the beginning of the 20th century. Therefore, the logic of quantum mechanics is recognized as a version of infinite-valued ukasiewicz logic. 相似文献
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Polycyclic ‘cage’ ketones, such as pentacyclo[5.4.0.02,6.03,10.05,9]undecan‐8‐one ( 10 ), pentacyclo[5.4.0.02,6.03,10.05,9]undecane‐8,11‐dione ( 11 ), and adamantan‐2‐one ( 16 ) were treated with the nucleophilic dimethoxycarbene (DMC; 1 ), which was generated thermally from 2,5‐dihydro‐2,2‐dimethoxy‐5,5‐dimethyl‐1,3,4‐oxadiazole ( 4a ) in boiling toluene. In this ‘one‐pot’ procedure, the α‐hydroxycarboxylic acid ester 12 or a corresponding derivative 15 or 17 was obtained (Schemes 4–7). Additionally, ‘cage’ thione 21 was treated with DMC under the same conditions yielding dimethoxythiirane 22 (Scheme 8). Subsequent hydrolysis or desulfurization (followed by hydrolysis on silica gel) of 22 gave α‐mercaptocarboxylate 25 and the corresponding desulfurized ester 24 , respectively. In all cases, the addition of DMC occurred stereoselectively, and the addition from the exo‐face is postulated to explain the structures of the isolated products. 相似文献
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