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排序方式: 共有158条查询结果,搜索用时 15 毫秒
1.
A short and highly efficient approach was applied for the total synthesis of the gypsy moth sex pheromone (+)-disparlure and its enantiomer from isopropylidene D- and L-erythrose, using a common strategy. 相似文献
2.
Demetrios Christodoulou 《Communications in Mathematical Physics》1987,109(4):613-647
We study the asymptotic behaviour, as the retarded timeu tends to infinity, of the solutions of Einstein's equations in the spherically symmetric case with a massless scalar field as the material model. We prove that when the final Bondi massM
1 is different from zero, asu , a black hole forms of massM
1 surrounded by vacuum. We find the rate of decay of the metric functions and the behaviour of the scalar field on the horizon.Research supported in part by National Science Foundation grants MCS-8201599 to the Courant Institute and PHY-8318350 to Syracuse University 相似文献
3.
A quantum mechanics/molecular mechanics molecular dynamics simulation was performed for liquid water to investigate structural and dynamical properties of this peculiar liquid. The most important region containing a central reference molecule and all nearest surrounding molecules (first coordination shell) was treated by Hartree-Fock (HF), post-Hartree-Fock [second-order Moller-Plesset perturbation theory (MP2)], and hybrid density functional B3LYP [Becke's three parameter functional (B3) with the correlation functional of Lee, Yang, and Parr (LYP)] methods. In addition, another HF-level simulation (2HF) included the full second coordination shell. Site to site interactions between oxygen-oxygen, oxygen-hydrogen, and hydrogen-hydrogen atoms of all ab initio methods were compared to experimental data. The absence of a second peak and the appearance of a shoulder instead in the gO-O graph obtained from the 2HF simulation is notable, as this feature has been observed so far only for pressurized or heated water. Dynamical data show that the 2HF procedure compensates some of the deficiency of the HF one-shell simulation, reducing the difference between correlated (MP2) and HF results. B3LYP apparently leads to too rigid structures and thus to an artificial slow down of the dynamics. 相似文献
4.
John K. Gallos Pygmalion S. Lianis Demetrios N. Nicolaides 《Journal of heterocyclic chemistry》1989,26(5):1415-1420
Reactions of furazano[3,4-b]quinoxalines 1 with phosphorus ylides 2 afford the transylidation product 3 and/or 4,9-dihydrofurazano[3,4-b]quinoxalines 4. Oxidation of 3 with phenyliodide bis-trifluoroacetate gave the fused furan derivative 13 in high yield. 相似文献
5.
6.
Demetrios D. Dionysiou 《General Relativity and Gravitation》1975,6(3):319-324
The main purpose of this paper is to present a formula of gravitational radiation recoil of an N-body material system. 相似文献
7.
Cohen O Freedman B Fleischer JW Segev M Christodoulides DN 《Physical review letters》2004,93(10):103902
We propose a method of optical waveguiding, which relies on Bragg diffractions from a 1D grating that gives rise to waveguiding in the direction normal to the grating wave vector. The waveguide structure consists of a shallow 1D grating that has a bell- or trough-shaped amplitude in the confinement direction. Finally, we provide an experimental proof of the concept for this mechanism. 相似文献
8.
Stable soliton complexes in two-dimensional photonic lattices 总被引:2,自引:0,他引:2
We show that two-dimensional photonic Kerr nonlinear lattices can support stable soliton complexes composed of several solitons packed together with appropriately engineered phases. This may open up new prospects for encoding pixellike images made of robust discrete or lattice solitons. 相似文献
9.
We demonstrate that both the linear (diffraction) and the nonlinear dynamics of two-dimensional waveguide arrays are considerably more complex and versatile than their one-dimensional counterparts. The discrete diffraction properties of these arrays can be effectively altered, depending on the propagation Bloch k-vector within the first Brillouin zone of the lattice. In general, this diffraction behavior is anisotropic and therefore permits the existence of a new class of discrete elliptic solitons in the nonlinear regime. 相似文献
10.
Fleischer JW Carmon T Segev M Efremidis NK Christodoulides DN 《Physical review letters》2003,90(2):023902
We report the first experimental observation of discrete solitons in an array of optically induced waveguides. The waveguide lattice is induced in real time by illuminating a photorefractive crystal with a pair of interfering plane waves. We demonstrate two types of bright discrete solitons: in-phase self-localized states and the staggered (pi out-of-phase) soliton family. This experiment is the first observation of bright staggered solitons in any physical system. Our scheme paves the way for reconfigurable focusing and defocusing photonic lattices where low-power (mW) discrete solitons can be thoroughly investigated. 相似文献