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81.
Mauricio D Garay 《Topology》2004,43(5):1081-1088
We introduce a cohomological approach to isochore deformation problems. We use this formulation in order to prove an isochore versal deformation theorem for holomorphic function germs. 相似文献
82.
Chau O. Shillor M. Sofonea M. 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2004,55(1):32-47
A model for the dynamic, adhesive, frictionless contact
between a viscoelastic body and a deformable foundation is
described. The adhesion process is modeled by a bonding field on
the contact surface. The contact is described by a modified normal
compliance condition. The tangential shear due to the bonding
field is included. The problem is formulated as a coupled system
of a variational equality for the displacements and a differential
equation for the bonding field. The existence of a unique weak
solution for the problem is established, together with a partial
regularity result. The existence proof proceeds by construction of
an appropriate mapping which is shown to be a contraction on a
Hilbert space. 相似文献
83.
《Magnetic resonance in chemistry : MRC》2003,41(8):626-628
15N isotopic enrichment was necessary for the unequivocal assignment of the 1H NMR lines to the protons in the NH–OH fragment of benzohydroxamic acid, BHXA, C6H5CONHOH, in dry dimethyl sulfoxide solutions. The assignment [δ(NH) = 11.21, δ(OH) = 9.01, 1J(15N,1H) = 102.2 Hz, 2J(15N,1H) <1.5 Hz], which is opposite to that used by other authors, confirms the assignment extended to BHXA by Brown and co‐workers from the spectra of acetohydroxamic acid. The enrichment allowed also assignment of the 29Si lines in the spectra of disilylated benzohydroxamic acid, (Z)‐tert‐butyldimethylsilyl N‐tert‐butyldimethylsilyloxybenzoimidate (2) and (Z)‐tert‐butyldiphenylsilyl N‐tert‐butyldiphenylsilyloxybenzoimidate (3), and confirmed structure of the monosilylated products, N‐tert‐butyldiphenylsilyloxybenzamide (4) and N‐tert‐butyldiphenylsilyloxy benzoimidic acid (5). Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
84.
《Magnetic resonance in chemistry : MRC》2003,41(1):61-64
Palladium(II) dichloride reacts with 1,10‐bis(2‐pyrrolyl)‐2,5,9‐triaza‐1,9‐decadiene to give a [Pd(C15H20N5)]Cl complex in which the ligand is four‐coordinated, leaving one pyrrole group dangling. By using COSY, gHSQC, gHMBC connectivities and NOE experiments it has been concluded that one linkage isomer exists in DMSO solution, in spite of the fact that different sets of N atoms of potentially pentadentate ligand might be involved in coordination, and that the three chelate rings in the complex cation are arranged in a sequence: five‐membered, six‐membered, five‐membered which is different from that (5–5–6) found by x‐ray studies on the related [Ni(C15H20N5)]Cl compound. NMR studies allowed an unambiguous assignment of all 1H and 13C NMR resonances for the complex. Results of x‐ray structural analysis of [Pd(C15H20N5)](CH3COO)H2O supported the five‐membered, six‐membered, five‐membered ring sequence in the [Pd(C15H20N5)]+ complex cation and show an E (trans) orientation of the dangling pyrrole group with respect to the metal center. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
85.
DEBACHE Abdelmadjid BOULCINA Raouf TAFER Radia BELFAITAH Ali RHOUATI Salah CARBONI Bertrand 《中国化学》2008,26(11):2112-2116
The synthesis of 1,2,3,4-dihydropyrimidinone/thione derivatives was achieved in good to excellent yields using calcium(II) nitrate as catalyst to promote the Biginelli three-component condensation reaction from a diversity of aromatic aldehydes, β-keto compounds and urea or thiourea. The reaction was carried out under solvent-free conditions. 相似文献
86.
87.
《Magnetic resonance in chemistry : MRC》2003,41(1):77-79
The complete assignment of the 1H and 13C NMR spectra of the title enediones, bearing as substituents N‐aziridinyl (a novel compound), methoxy, chloro and methylsulfanyl, is reported. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
88.
The dynamic external hashing proposed in this paper allocates records according to the spiral storage technique. Separators derived from the signature technique are used for distinguishing primary from overflow records and for subdividing overflow chains into segments allocated into the primary file. Single access retrieval is obtained by means of a main memory index with an entry per bucket and containing separators and pointers. While this method uses a larger index than other recent proposals, it is much more convenient regarding load factor and insertion cost. Furthermore, file expansion is directed by various control parameters, thus allowing the user to choose the most suitable policy for his application. 相似文献
89.
P. Tekely V. G rardy P. Palmas D. Canet A. Retournard 《Solid state nuclear magnetic resonance》1995,4(6):361-367
A simple modification of the standard cross-polarization method designed for quenching the proton T1ρ dependence when studying polarization transfer is presented. It is demonstrated that by using this simple procedure, new and subtle details of cross-polarization dynamics, previously hidden by the T1ρ(1H) effect, can be observed in dipolar-coupled spin systems. 相似文献
90.
报道了掺硫和掺氧NaCl:(F2^+)H色心激光器最新实验结果。最高输出功率分别达3W和4.8W。实验比较了掺硫及掺氧(F2^+)H心的热光稳定性。 相似文献