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21.
The reaction of a new fluorinated unsymmetrical allenylazine with dimethyl acetylenedicarboxylate and phenylacetylene affords the combined intra-intermolecular criss-cross cycloaddition products, 2,3-disubstituted-1,10-diazatricyclo[5.2.1.04,10]deca-2,6-diene derivatives. The products contain three fused five-membered rings with two nitrogen atoms within an unsaturated heterocyclic system. The structures were assigned using 2D NMR correlations and in the case of the phenylacetylene adduct by X-ray structure analysis. 相似文献
22.
The existence of a Nash equilibrium in the undiscounted repeated two-person game of incomplete information on one side is
established. The proof depends on a new topological result resembling in some respect the Borsuk-Ulam theorem. 相似文献
23.
W. Królas A. Maj P. Bednarczyk B. Fornal W. Mceczynski J. Styczeń M. Zicebliński 《Zeitschrift für Physik A Hadrons and Nuclei》1992,344(2):145-147
High-energy gamma-rays emitted in the decay of the giant dipole resonance built on excited states of55Mn nucleus were measured with a bismuth germanate detector. Resonance parameters were extracted from the fits to the experimental spectra. Two new high-energy calibration points originating from slow-neutron capture in germanium isotopes of bismuth germanate crystal are proposed for large-volume BGO detectors. 相似文献
24.
We study the Friedmann-Robertson-Walker model with dynamical dark energy modelled in terms of the equation of state p
X
= w
X
(a(z)) ρ
X
in which the coefficient w
X
is parameterized by the scale factor a or redshift z. We use methods of qualitative analysis of differential equations to investigate the space of all admissible solutions for
all initial conditions on the two-dimensional phase plane. We show advantages of representing this dynamics as a motion of
a particle in the one-dimensional potential V(a). One of the features of this reduction is the possibility of investigating how typical big rip singularities are in the
future evolution of the model. The properties of potential function V can serve as a tool for qualitative classification of all evolution paths. Some important features like resolution of the
acceleration problem can be simply visualized as domains on the phase plane. Then one is able to see how large is the class
of solutions (labelled by the inset of the initial conditions) leading to the desired property. 相似文献
25.
Orotic acid (vitamin B13) is a key intermediate in biosynthesis of the pyrimidine nucleotides in living organisms, moreover, it may serve as the biological carrier for some metal ions. cis-Diammine(orotato)platinum(II), cis-[Pt(C5H2N2O4)(NH3)2] can be considered as a new potential cisplatin analogue. The FT-Raman and FT-IR spectra of the title complex are reported, for the first time. The molecular structure, vibrational frequencies, and the theoretical infrared and Raman intensities have been calculated by the density functional mPW1PW91 method. The detailed vibrational assignment has been made on the basis of the calculated potential energy distribution. The theoretically predicted IR and Raman spectra show very good agreement with experiment. Natural bond orbital (NBO) analyses were performed for cisplatin, carboplatin and the title complex. The results provided new data on the nature of platinum–ligand bonding in these compounds. Strong intramolecular hydrogen bond between the orotate ligand and the coordinated ammonia group stabilizes the structure of the platinum(II) complex. Thus, it is suggested that the orotate ligand in the title complex is more inert to the substitution reactions than the chloride ligands in cisplatin. 相似文献
26.
Zdzisław Denkowski Leszek Gasiński Nikolaos S. Papageorgiou 《Journal of Global Optimization》2006,34(3):317-337
We study a resonant semilinear elliptic hemivariational inequality. Under some assumptions of strong resonance on the Clarke
subdifferential of the superpotential, and using nonsmooth critical point theory, the existence of a nontrivial solution of
the problem is shown.
This paper has been partially supported by the State Committee for Scientific Research of Poland (KBN) under research grants
no. 2 P03A 003 25 and no. 4 T07A 027 26. 相似文献
27.
28.
We give characterizations of continuous distributions in terms of moments of order statistics when the sample size is random.
In particular, we characterize uniform, exponential, Pareto, and logistic distributions. Special cases of a random sample
size (logarithmic series, geometrical, truncated binomial, truncated negative binomial, and truncated Poisson distribution)
are also considered.
Proceedings of the XVII Seminar on Stability Problems for Stochastic Models, Kazan, Russia, 1995, Part I. 相似文献
29.
Janusz Mierczyński Wenxian Shen Xiao-Qiang Zhao 《Journal of Differential Equations》2004,204(2):471-510
The purpose of this paper is to investigate uniform persistence for nonautonomous and random parabolic Kolmogorov systems via the skew-product semiflows approach. It is first shown that the uniform persistence of the skew-product semiflow associated with a nonautonomous (random) parabolic Kolmogorov system implies that of the system. Various sufficient conditions in terms of the so-called unsaturatedness and/or Lyapunov exponents for uniform persistence of the skew-product semiflows are then provided. Among others, it is shown that if the associated skew-product semiflow has a global attractor and its restriction to the boundary of the state space has a Morse decomposition which is unsaturated or whose external Lyapunov exponents are positive, then it is uniformly persistent. More specific conditions are discussed for uniform persistence in n-species, particularly 3-species, random competitive systems. 相似文献
30.
JPC – Journal of Planar Chromatography – Modern TLC - Emodin and twelve phenolic acids (ellagic, gallic, protocatechuic, homoprotocatechuic, caffeic, p-hydroxybenzoic, p-coumaric,... 相似文献