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961.
S. R. Grace 《Mathematische Nachrichten》1989,142(1):297-305
New theorems on the oscillatory and asymptotic behavior of solutions of the damped differential equations with deviating arguments of the form are established. 相似文献
962.
G. P. Jones B. A. Cornell E. Horn E. R. T. Tiekink 《Journal of chemical crystallography》1989,19(4):715-723
The crystal structures of dimethylsuccinate (DMS) and dimethyloxalate (DMO) have been determined to facilitate the determination of the C-13 chemical shielding tensors of the carbonyl carbon in esters. Crystals of DMS are monoclinic, space groupC2/c,Z=4,a=13.154(4),b=6.156(1),c=9.363(4)Å,=98.53(3)°. The structure was solved by direct methods and refined by leastsquares procedures to giveR=0.071 for 932 observed data. Crystals of DMO are monoclinic space group,P21/n,Z=2, witha=3.891(1),b=11.879(2),c=6.213(2) Å,=103.32(2)°. The structure is the same (within experimental error) as that reported by Dougill and Jeffrey (1953) and refined to giveR=0.074 for 395 observed data. 相似文献
963.
John R. Peterson Tamara J. Winter Hoang D. Do Robin D. Rogers 《Journal of chemical crystallography》1989,19(1):135-145
Structural and conformational information obtained from the crystal structure and solution1H nmr investigations of the title compound are compared. The 4-aryltetralone, C24H24O10, crystallizes as a chloroform solvate in the monoclinic space group, P21/n, witha=12.519(4),b=17.938(6),c=12.534(9)Å,=111.90(5)°, and Dcalc=1.51 g cm–3 forZ=4. The data for this compound were collected at –150°C. Least-squares refinement of 2796 observed [F
o5(F
o)] reflections led to the final agreement index ofR=0.062. A threefold static disorder was observed for one of the carboxyl groups. The second carboxyl group participates in an intramolecular hydrogen bond and is thus ordered. The1H nmr spectrum revealed the title compound to exist as a keto-enol tautomeric mixture in solution. Vicinal hydrogen coupling constant analysis proved reliable in ascertaining B-ring stereochemistry of 2,3-disubstituted-4-aryltetralones. 相似文献
964.
After recalling the basic properties of para-coKählerian manifolds \(\tilde M\) with concircular structure vector field ξ, the infinitesimal auto morphismsX of the structure 1-form \(\tilde \eta \) are considered. One of the results is that the Lie derivative of all powers of the structure 2-form \(\tilde \Omega ,\) i.e. \(\mathcal{L}x\tilde \Omega ^p ;p = 1,...,m,\) is exterior recurrent. Further two types of horizontal distributionsD n which are normal to ξ. IfD t (resp.D n ) is involutive, the corresponding leafM t (resp.M n ) is a minimal submanifold of \(\tilde M\) . FurtherM n is a symplectic submanifold and ξ is an umbilical normal section ofM n . Finally proper immersion \(M \to \tilde M\) are discussed, whereM is aCR-sub-manifold whose horizontal distribution isD t . It is shown that the vertical distribution is involutive, and the restriction of ξ toM is an symptotic direction. Some interesting special cases are treated. 相似文献
965.
R. M. Megrabian 《Analysis Mathematica》1988,14(1):37-47
В статье рассматрива ются множестваM N , 1≦N<∞ всех систем функций Φ={?(x)} j =1/N , заданных на [0,1] с где (ε i, j ) i, j =1/N — матрица с э лементами ± 1. Изучаетс я поведение наМ N функц ии $$\alpha _N (\Phi ) = \mathop {\sup }\limits_\sigma \mathop {\sup }\limits_{\sum a_j^2 = 1} (\int\limits_0^1 {\mathop {\sup }\limits_{1 \leqq k \leqq N} (\sum\limits_{j = 1}^k {a_j \varphi _{\sigma (j)} (x)} } )^2 dx)^{1/2} $$ гдеσ: {1, ...,N}?{1, ...,N}. Дока зьгаается, что сущест вуют абсолютные постоянн ыеc 3,c 4>0,y 0>1, такие, что для любог оN=1,2, ... иy>y 0 $$\mu _N (\{ \Phi \in {\rm M}_{\rm N} :\alpha _N (\Phi )/\left\| \Phi \right\| > y\} ) \leqq c_3 \exp [ - \exp (c_4 y)N]$$ гдеμ N — мера наM N с µ N ({Ф}) = 2?N2 дл я любой системыΦ∈M 相似文献
966.
Ya. Yu. Nikitin 《Journal of Mathematical Sciences》1988,43(6):2833-2838
The rough asymptotic behavior of the probability of large deviations is found for Watson-Darling goodness-of-fit tests, which are centered versions of Kolomogorov-Smirnov statistics. Their Bahadur effectiveness is calculated and conditions for local asymptotic optimality for the alternative of translation are studied.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 158, pp. 138–145, 1987. 相似文献
967.
We study sequences (X
0, X
1, ...) of random variables, taking values in the positive integers, which grow faster than branching processes in the sense that
, for m, n0, where the X
n
(m, i) are distributed as X
n
and have certain properties of independence. We prove that, under appropriate conditions, X
n
1/n
almost surely and in L
1, where =sup E(X
n
)1/n
. Our principal application of this result is to study the Lebesgue measure and (Hausdorff) dimension of certain projections of sets in a class of random Cantor sets, being those obtained by repeated random subdivisions of the M-adic subcubes of [0, 1]
d
. We establish a necessary and sufficient condition for the Lebesgue measure of a projection of such a random set to be non-zero, and determine the box dimension of this projection.Work done partly whilst visiting Cornell University with the aid of a Fulbright travel grant 相似文献
968.
969.
In this paper we construct the large-time solution of the equation
which models the effectof nonlinear absorption on thin film flow of a viscous fluidon a sloping bed. For initial data with finite support we showhow the asymptotic structure of the Cauchy problem depends onthe absorption index . An important addition motivation forthe study is to provide a basis for extending the results tothe more general equation
which has applications in plasma physics. 相似文献
970.
Thresholds for the detection of the direction of travel of a moving sound source were determined in a single-interval, forced-choice paradigm. Both the rate at which the sound source is displaced (8 degrees-128 degrees/s) and the frequency of the signal to be localized (500-3700 Hz) affect dynamic spatial resolution. There is an inverse relationship between spatial resolution and the rate of travel, a finding that replicates an earlier observation on performance with sources displaced at high velocities [Perrott and Musicant, J. Acoust. Soc. Am. 62, 1463-1466 (1977)]. However, the magnitude of this effect depends on the actual velocities employed. Relatively small changes in spatial resolution are apparent for velocities below approximately 32 degrees/s. The significant frequency effect can be summarized as follows: Dynamic spatial resolution is better for signals below 1000 Hz than for signals above this value (within the range tested). Particularly poor resolution is evident for signals between 1300-2000 Hz. The present results indicate that signal frequency affects dynamic spatial resolution in a fashion similar to that which has been observed in the more common "static" localization test situation. There is no indication of an interaction between these two variables. These results provide additional support for the hypothesis that both static and dynamic spatial discrimination functions are dependent upon the same underlying mechanisms. The effects of velocity upon the spatial resolution problem, a unique aspect of the dynamic paradigm, can probably be explained without the necessity of additional hypothetical mechanisms in the auditory system (e.g., a specialized motion detector). 相似文献