The integrability character of nonlinear equations of motion of two-dimensional gravity with dynamical torsion and bosonic string coupling is studied in this paper. The space-like and time-like first integrals of equa...The integrability character of nonlinear equations of motion of two-dimensional gravity with dynamical torsion and bosonic string coupling is studied in this paper. The space-like and time-like first integrals of equations of motion are also found.展开更多
The Left Hand of Darkness (abbr. LHD) is composed by Ursula Le Guin as a "thought experiment" to explore the postgender world on the planet of Gethen. By eradication of sexual difference and embracing the biologic...The Left Hand of Darkness (abbr. LHD) is composed by Ursula Le Guin as a "thought experiment" to explore the postgender world on the planet of Gethen. By eradication of sexual difference and embracing the biological fluidity and psychological androgeny, dualism is deconstructed, and a postgender intersubjective space is reconstructed between Genly Ai and Estraven, interluded by cyborg myth and postgenderism culture narratives. Moreover, Le Guin suggests a possible transformation mode ofyin-yang cycle from psychoanalytic light and shadow.展开更多
The equations of motion of a bubble, expanding adiabatically through an incompressible viscous fluid, are deduced when the centre of the bubble moves in a vertical plane in the presence of gravitational acceleration, ...The equations of motion of a bubble, expanding adiabatically through an incompressible viscous fluid, are deduced when the centre of the bubble moves in a vertical plane in the presence of gravitational acceleration, acting vertically downwards. The non-linear equations of motion obtained are solved numerically for different values of the various parameters of the problem. The path traced by the centre of the bubble and velocity of the centre, the change of radius R with time, and the influence of the buoyancy force, which is experienced by the expanding bubble for different values of the gravitational acceleration on these quantities, are investigated. The radius R(t) of the bubble is found to vary periodically with time when the acceleration due to gravity is small. But when the acceleration due to gravity increases, this periodicity in the value of R(t) with t is lost. The influence of viscosity in determining the periodicity of the bubble motion is also investigated.展开更多
The maximum of g2-d2 for linear [n, k, d; q] codes C is studied. Here d2 is the smallest size of the support of 2-dimensional subcodes of C and g2 is the smallest size of the support of 2-dimensional subcodes of C whi...The maximum of g2-d2 for linear [n, k, d; q] codes C is studied. Here d2 is the smallest size of the support of 2-dimensional subcodes of C and g2 is the smallest size of the support of 2-dimensional subcodes of C which contains a codeword of weight d. The extra cost to the greedy adversary to get two symbols of information using some algorithm is g2-d2. For codes satisfying the fullrank condition of general dimensions, upper bounds on the maximum of g2-d2 are given. Under some condition we have got code C where g2-d2 reaches the upper bound.展开更多
Photonic structures with optical resonances beyond a single controllable mode are strongly desired for enhancing light±matter interactions and bringing about advanced photonic devices. However, the realization of...Photonic structures with optical resonances beyond a single controllable mode are strongly desired for enhancing light±matter interactions and bringing about advanced photonic devices. However, the realization of effective multimodal photonic structures has been restricted by the limited tunable range of mode manipulation, the spatial dispersions of electric fields or the polarization-dependent excitations. To overcome these limitations, we create a dualmode metasurface by integrating the plasmonic surface lattice resonance and the gap plasmonic modes;this metasurface offers a widely tunable spectral range, good overlap in the spatial distribution of electric fields, and polarization independence of excitation light. To show that such dual-mode metasurfaces are versatile platforms for enhancing light±matter interactions, we experimentally demonstrate a significant enhancement of second-harmonic generation using our design, with a conversion efficiency of 1±3 orders of magnitude larger than those previously obtained in plasmonic systems. These results may inspire new designs for functional multimodal photonic structures.展开更多
文摘The integrability character of nonlinear equations of motion of two-dimensional gravity with dynamical torsion and bosonic string coupling is studied in this paper. The space-like and time-like first integrals of equations of motion are also found.
文摘The Left Hand of Darkness (abbr. LHD) is composed by Ursula Le Guin as a "thought experiment" to explore the postgender world on the planet of Gethen. By eradication of sexual difference and embracing the biological fluidity and psychological androgeny, dualism is deconstructed, and a postgender intersubjective space is reconstructed between Genly Ai and Estraven, interluded by cyborg myth and postgenderism culture narratives. Moreover, Le Guin suggests a possible transformation mode ofyin-yang cycle from psychoanalytic light and shadow.
文摘The equations of motion of a bubble, expanding adiabatically through an incompressible viscous fluid, are deduced when the centre of the bubble moves in a vertical plane in the presence of gravitational acceleration, acting vertically downwards. The non-linear equations of motion obtained are solved numerically for different values of the various parameters of the problem. The path traced by the centre of the bubble and velocity of the centre, the change of radius R with time, and the influence of the buoyancy force, which is experienced by the expanding bubble for different values of the gravitational acceleration on these quantities, are investigated. The radius R(t) of the bubble is found to vary periodically with time when the acceleration due to gravity is small. But when the acceleration due to gravity increases, this periodicity in the value of R(t) with t is lost. The influence of viscosity in determining the periodicity of the bubble motion is also investigated.
基金This paper was presented at International Congress of Mathematicians,August 20-28,2002,BeijingThis work was supported by the Norwegian Research Council and the National NaturalScience Foundation of China(GrantNo.10271116).
文摘The maximum of g2-d2 for linear [n, k, d; q] codes C is studied. Here d2 is the smallest size of the support of 2-dimensional subcodes of C and g2 is the smallest size of the support of 2-dimensional subcodes of C which contains a codeword of weight d. The extra cost to the greedy adversary to get two symbols of information using some algorithm is g2-d2. For codes satisfying the fullrank condition of general dimensions, upper bounds on the maximum of g2-d2 are given. Under some condition we have got code C where g2-d2 reaches the upper bound.
基金supported by the National Key R&D Program of China (2016YFA0301300)the National Natural Science Foundation of China (11974437 and 91750207)+6 种基金the Key-Area Research and Development Program of Guangdong Province (2018B030329001)Guangdong Special Support Program (2017TQ04C487)Guangdong Natural Science Funds for Distinguished Young Scholars (2017B030306007)Guangdong Natural Science Funds (2020A0505140004)Pearl River S&T Nova Program of Guangzhou (201806010033)the Open Fund of IPOC (BUPT) (IPOC2019A003)the Fundamental Research Funds for the Central Universities (20lgzd30)。
文摘Photonic structures with optical resonances beyond a single controllable mode are strongly desired for enhancing light±matter interactions and bringing about advanced photonic devices. However, the realization of effective multimodal photonic structures has been restricted by the limited tunable range of mode manipulation, the spatial dispersions of electric fields or the polarization-dependent excitations. To overcome these limitations, we create a dualmode metasurface by integrating the plasmonic surface lattice resonance and the gap plasmonic modes;this metasurface offers a widely tunable spectral range, good overlap in the spatial distribution of electric fields, and polarization independence of excitation light. To show that such dual-mode metasurfaces are versatile platforms for enhancing light±matter interactions, we experimentally demonstrate a significant enhancement of second-harmonic generation using our design, with a conversion efficiency of 1±3 orders of magnitude larger than those previously obtained in plasmonic systems. These results may inspire new designs for functional multimodal photonic structures.