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991.
M.A. Chmielewski 《Journal of multivariate analysis》1980,10(3):343-350
The usual assumption in multivariate hypothesis testing is that the sample consists of n independent, identically distributed Gaussian m-vectors. In this paper this assumption is weakened by considering a class of distributions for which the vector observations are not necessarily either Gaussian or independent. This class contains the elliptically symmetric laws with densities of the form f(X(n × m)) = ψ[tr(X ? M)′ (X ? M)Σ?1]. For testing the equality of k scale matrices and for the sphericity hypothesis it is shown, by using the structure of the underlying distribution rather than any specific form of the density, that the usual invariant normal-theory tests are exactly robust, for both the null and non-null cases, under this wider class. 相似文献
992.
Thomas T. Tidwell 《Tetrahedron letters》1979,20(48):4615-4618
Diethylketene and organometallic reagents form enolates capturable by methyl iodide or trimethylsilyl chloride with greater than 95% positional selectivity. 相似文献
993.
994.
Bruce A. Carlson Jean-Jacques Katz Herbert C. Brown 《Journal of organometallic chemistry》1974,67(2):C39-C42
Treatment of hindered borinic esters, R2 BOR′; with an equimolar quantity of α,α-dichloromethyl methyl ether and lithium triethylcarboxide yields the α-chloroboronic esters, R2 CHClB(OCH3)OR′, in excellent yields. In cases where the steric requirements of R are not sufficient, the steric requirements of R′ can be increased to achieve the synthesis. 相似文献
995.
996.
Charles B. Dunham 《Aequationes Mathematicae》1981,22(1):165-172
997.
M. Van De Vel 《Topology and its Applications》1983,16(2):181-206
It is shown that two-dimensional convex structures with certain natural properties are join-hull commutative. The main intermediate step is the computation of the so-called exchange number. We also give two examples of three-dimensional convexities which are not join-hull commutative. The second one has certain additional properties showing that the main theorem is sharp in many other respects. These properties are obtained from a study of convex hyperspaces. 相似文献
998.
Marc Prevost 《Journal of Computational and Applied Mathematics》1983,9(4):333-346
The interpolation of the function x → 1/(1 ? xt) generating the series f(t) = ∑∞i = 0citi at the zeros of an orthogonal polynomial with respect to a distribution d α satisfying some conditions will give us a process for accelerating the convergence of fn(t) = ∑ni = 0citi. Then, we shall see that the polynomial of best approximation of x → 1/(1 ? xt) over some interval or its development in Chebyshev polynomials Tn or Un are only particular cases of the main theorem.At last, we shall show that all these processes accelerate linear combinations with positive coefficients of totally monotonic and oscillating sequences. 相似文献
999.
The energy transfer phenomenon has been studied from Tb3+ → Nd3+ and Tb3+ → Ho3+ in DMSO. A diffusion limited dipole-dipole mechanism of energy transfer is suggested for both systems. At high acceptor concentrations, Pda depends linearly on C2 consistent with the Fong and Diestler theory of energy transfer. However, at low acceptor concentrations the observations of time evolutions of Tb3+ luminescence decay following flash excitation has enabled us to examine diffusion limited energy transfer from Tb3+ to Nd3+ and Tb3+ to Ho3+ in DMSO. 相似文献
1000.
A general quadratic force field is determined for the out-of-plane vibrations of florobenzenes. The force constants for the out-of-plane wagging of both CH and CF bonds decrease by about 10 % for each ortho fluorine substituent. No significant meta dependence could be detected. It is shown that the present field is in excellent accord with the chlorobenzene field of Scherer and with the benzene fields of Whiffen and of Kydd when due allowance is made for differences in coordinate definitions. 相似文献