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1.
Yang T. L. Kao C. L. Kuo C. E. Yeh H. C. Li W. J. Li H. T. Chen C. Y. 《Chemistry of Natural Compounds》2022,58(5):825-827
Chemistry of Natural Compounds - A novel bibenzyl derivative, hydrangchinenin (1), was isolated from the stems of Hydrangea chinensis Maxim. (Hydrangeaceae). Its structure was determined on the... 相似文献
2.
In this paper, a bivariate generating function CF(x, y) =f(x)-yf(xy)1-yis investigated, where f(x)= n 0fnxnis a generating function satisfying the functional equation f(x) = 1 + r j=1 m i=j-1aij xif(x)j.In particular, we study lattice paths in which their end points are on the line y = 1. Rooted lattice paths are defined. It is proved that the function CF(x, y) is a generating function defined on some rooted lattice paths with end point on y = 1. So, by a simple and unified method, from the view of lattice paths, we obtain two combinatorial interpretations of this bivariate function and derive two uniform partitions on these rooted lattice paths. 相似文献
3.
Addition of functionalized zinc-copper reagents to the title complexes proceeds in a highly diastereoselective fashion to afford dienol complexes. The relative configurations of adducts 3d were determined by single X-ray diffraction analysis. 相似文献
4.
This paper describes several combinatorial models for Laguerre, Charlier, and Hermite polynomials, and uses them to prove combinatorially some classical formulas. The so-called “Italian limit formula” (from Laguerre to Hermite), the Appel identity for Hermite polynomials, and the two Sheffer identities for Laguerre and Charlier polynomials are proved. We also give bijective proofs of the three-term recurrences. These three families form the bottom triangle in R. Askey's chart classifying hypergeometric orthogonal polynomials. 相似文献
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6.
The aim of this paper is to investigate homomorphisms which reserve square-free languages or primitive languages. A characterization of square-free-preserving homomorphisms is presented. We show that every square-free-preserving homomorphism is primitive-preserving. Strongly cube-free-preserving homomorphisms are also studied. 相似文献
7.
Iradj Ouveysi Andrew Wirth Annie Yeh Osman Oğuz 《Annals of Operations Research》2003,124(1-4):285-293
We consider the problem of providing a minimum cost multi-service network subject to one link failure scenarios. We assume our network is fully meshed and demand is satisfied by using direct or two hop-paths. We provide a large scale linear programming formulation and propose and test two effective heuristics. 相似文献
8.
Nickel and cobalt films illustrate alternative Bloch lines with cap switches. The strip magnetic domains become zigzag and bubbling cells for Ni and Co films, respectively, under an external field of 1.5 T. The magnetoresistances (MR) for currents parallel (CIW) to the domain walls is 15% less than those of the perpendicular (CPW) case. We also studied the magneto size effect by applying the magnetic field normal to the surface, from which the Sondheimer oscillation appears attributing to periodic striking of the surface for electrons traveling in circular motion on a plane canting to the surface. The experiments can be expressed by the magneto size effect inherited with very small specularity parameters. 相似文献
9.
Ching-Cherng Sun You-Nian Lin Shih-Po Yeh Wei-Chia Su Yuh Ouyang 《Optics & Laser Technology》2002,34(7):523-526
High longitudinal selectivity of the shifting multiplexing with spherical reference wave is proposed and demonstrated. A simplified method based on wave optics is used for calculating the selectivity, and the result fits well the experimental measurement. Under the paraxial condition, a simple formula for the longitudinal selectivity is introduced. With use of an object lens with effective NA=0.817, we obtain that an FWHM of selectivity is as small as 1 μm. 相似文献
10.
The Wiener (Sum of All Distances) Index for three out of the four classes of hexagonal models or regular planar hex-patterns used to model graphite and similar structures have been known for a few years. In this paper we find the Wiener Index for the Crown or Beehive hexagonal model. 相似文献