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1.
We consider (classical and generalized) Massey products on the Chekanov homology of a Legendrian knot, and we prove that they are invariant under Legendrian isotopies. We also construct a minimal A-algebra structure on the Chekanov algebra of a Legendrian knot, we prove that this structure is invariant under Legendrian isotopy, and we observe that its higher multiplications allow us to find representatives for classical Massey products. Finally, we consider differential equations: we remark that the Massey product Legendrian invariants admit a “dynamical interpretation”, in the sense that they provide solutions for a Maurer-Cartan equation posed on an infinite-dimensional bigraded Lie algebra, and we show how to set up and solve a (twisted) Kadomtsev-Petviashvili hierarchy of equations starting from the Chekanov algebra of a Legendrian knot.  相似文献   

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田浩  刘海韬  程海峰 《中国物理 B》2014,23(2):25201-025201
A thin radar-infrared stealth-compatible structure with reflectivity below -10 dB in the whole radar X wave band and infrared emissivity less than 0.3 in the infrared region of 8μm-14 μm is reported. The designed stealth-compatible structure consists of metallic frequency selective surface (MFSS), resistive frequency selective surface (RFSS), and metal backing from the top down, and it is only 2. l-mm thick. The MFSS is made up of some divided low infrared emissivity metal copper films, and the RFSS consists of a capacitive array of square resistive patches. They are placed close together, working as an admittance sheet because of a mutual influence between them, and the equivalent admittance sheet greatly reduces the thickness of the whole structure. The proposed stealth-compatible structure is verified both by simulations and by experimental results. These results indicate that our proposed stealth-compatible structure has potential applications in stealth fields.  相似文献   

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Ultrasound induced cavitation (acoustic cavitation) process is found useful in various applications. Scientists from various disciplines have been exploring the fundamental aspects of acoustic cavitation processes over several decades. It is well documented that extreme localised temperature and pressure conditions are generated when a cavitation bubble collapses. Several experimental techniques have also been developed to estimate cavitation bubble temperatures. Depending upon specific experimental conditions, light emission from cavitation bubbles is observed, referred to as sonoluminescence. Sonoluminescence studies have been used to develop a fundamental understanding of cavitation processes in single and multibubble systems. This minireview aims to provide some highlights on the development of basic understandings of acoustic cavitation processes using cavitation bubble temperature, sonoluminescence and interfacial chemistry over the past 2–3 decades.  相似文献   

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We investigate the problem of computing $$\lim_{N \to \infty}\frac{1}{aN}\log EZ_N^a$$ for any value of a, where Z N is the partition function of the celebrated Sherrington-Kirkpatrick (SK) model, or of some of its natural generalizations. This is a natural “large deviation” problem. Its study helps to get a fresh look at some of the recent ideas introduced in the area, and raises a number of natural questions. We provide a complete solution for a ≥ 0.  相似文献   

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The present state of theory and experiment on the gravity-induced electric field in metallic conductors and the electric field in accelerated metal conductors is reviewed. The relevant equations are derived in very simple approximations. The results depend on whether the deformation of the lattice of positive ions is neglected or is taken into account. Experimental results obtained with freely falling electrons in a cavity in the metal do not agree with the measurements of potentials on rapidly spinning metal rotors. Older direct measurements of the specific charge of carriers in metallic conductors are also mentioned.  相似文献   

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The 333.6-, 351.1-, and 363.8-nm lines of a cw argon ion laser are found to coincide with the BaS B1Σ+-X1Σ+ (12, 0) R(17), (6, 0) P(35), and (3, 0) R(125) transitions, respectively. Fluorescence transitions from the laser-prepared upper levels terminating in X1Σ+v = 0–28, A1Σ+v = 1–3, A1Π v = 1–13, and a3Π1v = 3–12 are assigned. These results are combined with a previous analysis of the extensively perturbed BaS A1Σ+-X1Σ+ system [R. F. Barrow, W. G. Burton, and P. A. Jones, Trans. Farad. Soc.67, 902–906 (1971)]. Every observed perturbation of the BaS A1Σ+ state is electronically and vibrationally assigned. The levels a3Π0v = 10–13, a3Π1v = 12–14, a3Π2v = 15, and A1Π v = 10–13 are sampled via their perturbations of A1Σ+v = 0–2. Although the mutual interactions of the a3Π, A1Π, and A1Σ+ states approach Hund's case (c) limit, a complete deperturbation is performed from a case (a) starting point. Of the five lowest energy electronic states of BaS, only b3Σ+ remains uncharacterized. Principal deperturbed molecular constants are (in cm?1, 1σ uncertainties in parentheses):
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Combing with the generalized Hamiltonian system theory,by introducing a special form of sinusoidal function,a class of n-dimensional(n=1,2,3)controllable multi-scroll conservative chaos with complicated dynamics is constructed.The dynamics characteristics including bifurcation behavior and coexistence of the system are analyzed in detail,the latter reveals abundant coexisting flows.Furthermore,the proposed system passes the NIST tests and has been implemented physically by FPGA.Compared to the multi-scroll dissipative chaos,the experimental portraits of the proposed system show better ergodicity,which have potential application value in secure communication and image encryption.  相似文献   

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We investigate the effects of shape and single-atom doping on the structural, optical absorption, Raman, and vibra- tional properties of Ag13, Ag12CUl, CUl3, and Cul2Agl clusters by using the (time-dependent) density functional the- ory. The results show that the most stable structures are cuboctahedron (COh) for Ag13 and icosahedron (Ih) for CUl3, Agl2CUlcore, and Cul2Aglsur. In the visible-near infrared optical absorption, the transitions consist of the interband and the intraband transitions. Moreover, red shifts are observed as follows: 1) clusters change from Agl2CUlcore to Ag13 to Ag12Culsur with the same motifs, 2) the shapes of pure Agl3 and Agl2CUlcore clusters change from COh to Ih to decahe- dron (Dh), 3) the shape of Agl2CUlsur clusters changes from Ih to COh to Dh, and 4) the shapes of pure CU13 and Cu12Agl clusters change from Ih to Dh to COb. All of the Raman and vibrational spectra exhibit many significant vibrational modes related to the shapes and the compositions of the clusters. The ranges of vibrational spectra of Ag13, Agl2CUl or CU13, and Cu12Agl clusters become narrower and the vibrational intensities increase as the shape of the clusters changes from Ih to Dh to COh.  相似文献   

12.
The data on the vector A y and tensor A yy , A xx , A xz analyzing powers for the d3H p reaction have been obtained at the energy of the initial deuteron of 200MeV in the angular range of 0–95 degrees in the c.m.s. The calculations performed within one-nucleon exchange model with the use of the standard three-nucleon bound state wave functions fail to reproduce the data on the tensor analyzing powers.  相似文献   

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This fairy tale begins with the journey of the famous Zhuang Zhou dreaming of a butterfly: I often do not know whether I am living in a dream, dreaming of a butterfly, or is a butterfly dreaming of me? Furthermore, there is the saying that those who believe it will see it, while for those who see it, it is then too late to believe it. The first thing I believe in is the holographic principle, and the holographic dark energy brought about by the holographic principle. Not until last year, I began...  相似文献   

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Polymer-derived SiCN ceramics, annealed (also referred to as pyrolyzed) at 1000, 1100, and 1285 °C, and doped with Fe(III) acetylacetonate, are investigated by electron paramagnetic resonance (EPR) from 4 to 120 K at X-band (9.425 GHz). In addition, the SiCN ceramic, annealed at 1100 °C, was studied by EPR at 300 K at W-band (93.96 GHz). There was observed a significant increase in EPR linewidth due to dangling bonds (g = 2.001) below 20 K at X-band. The low-field X-band FMR line (g ≈ 12) indicated the presence of ferromagnetic Fe5Si3 crystallites. There were found two EPR lines due to carbon-related dangling bonds: (1) those present as defects on the surface of the free-carbon phase (as sp2 carbon-related dangling bonds with g = 2.0011) and (2) those present within the bulk of carbon phase (as sp3 carbon-related dangling bonds with g = 2.0033). On the other hand, the intense low-field EPR signal observed at X-band was not observed at W-band. As well, there was observed splitting of the single broad EPR signal observed at g = 2.05 at X-band into two signals at W-band at g = 1.99 and g = 2.06, due to two different Fe-containing superparamagnetic nanocrystallites. Two new EPR signals, not observed at X-band, were observed at W-band, namely at g = 2.28 and g = 3.00, which are also due to g of these superparamagnetic nanocrystallites.  相似文献   

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The dilepton invariant mass spectra and integrated branching ratios of the single and double Dalitz decays P→l~+l~-γ and P→l~+l~-l~+l~-(P=π~0,η,η';l=e or μ) are predicted by means of a data-driven approach based on the use of rational approximants applied to π~0,η and η' transition form factor experimental data in the space-like region.  相似文献   

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Scintillator based coded-aperture imaging has proven to be effective when applied for X- and gamma-ray detection. Adaptation of the same method for neutron imaging has resulted in a number of propitious systems, which could be potentially employed for neutron detection in security and nuclear decommissioning applications. Recently developed scintillator based coded-aperture imagers reveal that localisation of neutron sources using this technique may be feasible, since pulse shape discrimination algorithms implemented in the digital domain can reliably separate gamma-rays from fast neutron interactions occurring within an organic scintillator. Moreover, recent advancements in the development of solid organic scintillators make them a viable solution for nuclear decommissioning applications as they present less hazardous characteristics than currently dominating liquid scintillation detectors. In this paper existing applications of coded-apertures for radiation detection are critically reviewed, highlighting potential improvements for coded-aperture based neutron source localisation. Further, the suitability of coded-apertures for neutron imaging in nuclear decommissioning is also assessed using Monte-Carlo modelling.  相似文献   

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The symmetry of the fermionic field is obtained by means of the Lax pair of the mKdV equation. A new super mKdV equation is constructed by virtue of the symmetry of the fermionic form. The super mKdV system is changed to a system of coupled bosonic equations with the bosonization approach. The bosonized SmKdV(BSmKdV)equation admits Painlevé property by the standard singularity analysis. The traveling wave solutions of the BSmKdV system are presented by the mapping and deformation method. We also provide other ideas to construct new super integrable systems.  相似文献   

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Inhomogeneous lattice paths are introduced as ordered sequences of rectangular Young tableaux thereby generalizing recent work on the Kostka polynomials by Nakayashiki and Yamada and by Lascoux, Leclerc and Thibon. Motivated by these works and by Kashiwara's theory of crystal bases we define a statistic on paths yielding two novel classes of polynomials. One of these provides a generalization of the Kostka polynomials, while the other, which we name the Anу supernomial, is a q-deformation of the expansion coefficients of products of Schur polynomials. Many well-known results for Kostka polynomials are extended leading to representations of our polynomials in terms of a charge statistic on Littlewood-Richardson tableaux and in terms of fermionic configuration sums. Several identities for the generalized Kostka polynomials and the Anу supernomials are proven or conjectured. Finally, a connection between the supernomials and Bailey's lemma is made.  相似文献   

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The pure rotational spectrum in the vibrational ground state [J. Bendtsen and F. M. Nicolaisen, J. Mol. Spectrosc. 119, 456–466 (1986)] and the infrared spectrum of the fundamental bands ν5 and ν6 [J. Bendtsen, F. Hegelund, and F. M. Nicolaisen, J. Mol. Spectrosc. 118, 121–131 (1986)] of HN3 have been simultaneously analyzed using a three-level model taking into account resonance between the ground state and ν5 due to centrifugal distortion [K. Yamada, J. Mol. Spectrosc. 81, 139–151 (1980)] and a- and b-Coriolis interactions between ν5 and ν6. A set of ground- and upper-state constants have been obtained and values for the centrifugal distortion parameter C5ab and the Coriolis coupling constant ζ5,6b are derived. A complete set of ground-state energies for J ≦ 50 and Ka ≦ 10 is tabulated.  相似文献   

TeωeωexeBe × 102αe × 104Re(A?)
A1Σ+14 498.6(1)287.7(1)1.15(5)9.365(5)5.0(10)2.633
A′1Π12 095(6)258.9(5)0.78.21(5)3.6(5)2.813
a3Πi11 835(6)259.6(5)0.78.213.62.813
X1Σ+0379.50(4)0.91(1)10.334(1)3.4(2)2.507
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