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101.
Janusz Adamus 《Proceedings of the American Mathematical Society》2002,130(11):3165-3170
Kwiecinski has proved a geometric criterion for flatness: A morphism of germs of analytic spaces is not flat if and only if its fibre power has a vertical component, for some . We show how to bound using Hironaka's local flattener: If is not flat, then has a vertical component, where is the minimal number of generators of the ideal in of the flattener of .
102.
Krzysztof Ciesielski Janusz Pawlikowski 《Proceedings of the American Mathematical Society》2002,130(7):2007-2013
We show that the property
- (P)
- for every Darboux function there exists a continuous nowhere constant function such that is Darboux
- (A)
- for every subset of of cardinality there exists a uniformly continuous function such that ,
- (B)
- for an arbitrary function whose image contains a non-trivial interval there exists an of cardinality such that the restriction of to is uniformly continuous,
103.
Ciucanu I Kaykhaii M Montero L Pawliszyn J Szubra J 《Journal of chromatographic science》2002,40(6):350-354
A novel method for the continuous monitoring of thermooxidative degradation products of polystyrene by membrane extraction with sorbent interface (MESI) and gas chromatography (GC) is developed. The results are compared with solid-phase microextraction-GC, which can extract gases, vapors, and aerosols. The volatile and semivolatile degradation products are identified by mass spectrometry. The membrane used in the MESI-GC analysis shows a high permeation for volatile aromatic hydrocarbons; a low permeation for corresponding volatile aldehydes; and no permeation for less volatile alcohols, acids, and degradation products with a high molecular weight, thus reducing significantly the number of compounds detected from MESI-GC. Sensitivity of the method depends on the time of trapping, which is limited by the breakthrough of the trap. By heating the trap at fixed intervals of time, consecutive gas chromatograms are obtained. 相似文献
104.
High-efficiency coupling structure for a single-line-defect photonic-crystal waveguide 总被引:1,自引:0,他引:1
Prather DW Murakowski J Shi S Venkataraman S Sharkawy A Chen C Pustai D 《Optics letters》2002,27(18):1601-1603
We present the design and fabrication of a planar structure for coupling light from a multimode feed waveguide into a single-line-defect photonic-crystal waveguide. Finite-difference time-domain calculations predict a coupling efficiency of greater than 90%, and preliminary experimental results indicate successful coupling through a single-line-defect photonic-crystal waveguide. Device design, fabrication, and characterization are presented. 相似文献
105.
Marina S. Fonari Yurii A. Simonov Victor Ch. Kravtsov Janusz Lipkowski Gabriele Bocelli Edward V. Ganin Vladimir O. Gelmboldt 《Journal of chemical crystallography》1999,29(12):1245-1254
Synthesis and single-crystal X-ray structures are recorded for three adducts of SbF3 with different azacrown ethers. [SbF3·H2O·L1], 1, (L1 = 12,13-benz-1,10-di(azamethyl)-4,7-dioxacyclotetradecane-1,14-dione), triclinic,
, a = 11.234(2), b = 11.691(2), c = 8.869(2) Å, = 94.66(3), = 113.12(3), = 67.82(3)°, Z = 2. [SbF3Cl·H2O·(HL2)], 2, (L2 = monoaza-18-crown-6), orthorhombic, P212121, a = 8.763(2), b = 13.003(3), a = 16.836(3) Å, Z = 4. [(SbF3)2Cl2·(H2L3)], 3, (L3 = 1,10-diaza-18-crown-6), triclinic,
, a = 8.284(2), b = 9.016(2), c = 9.134(2) Å, = 82.92(3), = 65.24(3), = 63.38(3)°, Z = 1. All three structures include SbF3 neutral molecules in the pyramidal mode and the antimony second coordination sphere is completed up to six in different fashions. In 1 the dimeric (SbF3)2 adducts are made up due to the involvement of the symmetry-related fluorine atom in coordination. The distorted octahedron is then completed by water molecule and carbonyl oxygen of L1. The neutral molecules are joined by coordination and hydrogen bonds in the infinite ribbons. 2 and 3 are both comprised of neutral and charged species also bounded via coordination and hydrogen bonds. L2 and L3 in the complexes adopt the form of single and double-charged cations, respectively. The inorganic backbone unites the neutral SbF3 molecules and chloride anions in the alternative mode. The sixth coordination site in the antimony polyhedron is completed by the water molecule in 2 and the ethereal oxygen atom in 3. Alignment of the inorganic entities within the structures of 2 and 3 is strikingly similar. Hydrogen bonding patterns are discussed. 相似文献
106.
Janusz Gwozdziewicz Krzysztof Kurdyka Adam Parusinski 《Proceedings of the American Mathematical Society》1999,127(4):1057-1064
We prove that every polynomial of degree has at most zeros on the curve . As a consequence we deduce that the existence of a uniform bound for the number of zeros of polynomials of a fixed degree on an analytic curve does not imply that this curve belongs to an o-minimal structure.
107.
Wladyslaw Biernacki Janusz Dabrowski Andrzej Ejchart 《Magnetic resonance in chemistry : MRC》1972,4(4):443-447
The role of steric factors in magnetic non-equivalence anisochronism of complex geminal groups and of their fragments in compounds of the general formula RCH(Ph)CH(COOR′)2 has been investigated. CMR anisochronism is more sensitive to conformational and other steric changes than is PMR. 相似文献
108.
109.
The reaction of hot hydrogen atoms originating from 253.7- and 228.8-nm photolyses of hydrogen sulfide with 1-butene was investigated. Of the hydrogen atoms undergoing addition a substantial part undergoes it in a first collision (37 and 48% at 253.7 and 228.8 nm, respectively) yielding highly excited butyl radicals. The ratio of nonterminal to terminal addition is 0.5 and practically does not depend on the energy of the hydrogen atoms over the range of 15–33 kcal/mol. Comparing the results of 229- and 254-nm photolyses of hydrogen sulfide with those of 313- and 334-nm photolyses of hydrogen iodide with the use of the decomposition rate constants of n-butyl radicals calculated by the RRKM methods, the conclusion is reached that the hydrogen atom from H2S photodissociation has 90–95% of the available energy. 相似文献
110.
Janusz Dabrowski Andrzej Ejchart Wadysaw Biernacki 《Magnetic resonance in chemistry : MRC》1970,2(3):311-316
Carbinols of the general formulae R·CHOH·C(NO2)Me2 exhibit increasing values of chemical shift non-equivalence for the geminal methyl groups with rise of temperature. This phenomenon furnishes indirect evidence for the intrinsic non-equivalence. 相似文献