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991.
Wang L. Y. Xu W. C. Luo Z. C. Cao W. J. Luo A. P. Dong J. L. Wang H. Y. 《Laser Physics》2011,21(10):1808-1812
We experimentally demonstrate a passively Q-switched mode-locking (QML) operation in an Erbium-doped fiber ring laser with
net normal dispersion by using nonlinear polarization rotation technique. A 2 m long section of dispersion compensating fiber
(DCF) with extra large positive dispersion was inserted into the cavity to ensure the fiber laser working in the region of
net positive dispersion. By carefully adjusting the polarization controller, both uniform dissipative mode-locking pulses
with fundamental repetition rate and QML pulse trains with tunable repetition rate from 71.58 to 98.83 kHz are achieved. It
is found that the QML operation is caused by the interaction between the polarization state of the pulse and the intracavity
polarizer. 相似文献
992.
Dr. Yuwei Zhang Caiyun Zhang Prof. Yirong Mo Prof. Zexing Cao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(4):1402-1409
Designing and synthesizing a stable compound with a planar tetracoordinate silicon (ptSi) center is a challenging goal for chemists. Here, a series of potential aromatic ptSi compounds composed of four conjugated rings shared by a centrally embedded Si atom are theoretically designed and computationally verified. Both Born–Oppenheimer molecular dynamics (BOMD) simulations and potential energy surface scannings verify the high stability and likely existence of these compounds, particularly Si-16-5555 (SiN4C8H8) with 16 π electrons, under standard ambient temperature and pressure. Notably, the Hückel aromaticity rule, which works well for single rings, is inconsistent with the high stability of Si-16-5555 where the 16 p electrons are spread over four five-membered rings fused together. Bonding analyses show that the strong electron donation from the peripheral 12-membered conjugated ring with 16 π electrons to the vacant central atomic orbital Si 3pz leads to the stabilization for both the ptSi coordination and planar aromaticity. The partial occupation of Si 3pz results in the peculiar carbenoid-type behaviors for the amphoteric center. By modulating the electron density on the ring with substituent groups, we can regulate the nucleophilic and electrophilic properties of the central Si. 相似文献
993.
Yong Zhang 《Journal of statistical physics》2010,139(5):915-939
This paper develops moment formulas for exponentially tempered, fractional advection-diffusion equations (TFADEs) that transition
from anomalous to asymptotic diffusion limits over time. Exact analytical expressions or series representations for spatial
moments up to the fourth order are derived by integral transform or asymptotic expansion approach. A fully Lagrangian solver,
cross verified by an implicit Eulerian approach, is also developed to calculate numerically the complete evolution of moments
for the TFADEs with complex initial and boundary conditions. Moment analysis identifies the diffusion equation that attracts
the tempered anomalous diffusion in the long time limit. Fitting of moments measured at two end members of alluvial systems
checks the applicability of moment analysis in understanding real diffusion. 相似文献
994.
Yong He 《Optics Communications》2010,283(7):1558-1560
We propose a scheme to generate a type of genuine four-qubit entangled states, which were firstly introduced by Yeo et al. [Y. Yeo, W. K. Chua, Phys. Rev. Lett. 96 (2006) 060502]. These states have many interesting entanglement properties and possess possible applications in quantum information processing and in fundamental tests of quantum physics. We show that such a type of 16 orthonormal basis states can be deterministically distinguished by a cavity QED system. 相似文献
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999.
Haihui Cao Guoxing Lin Alan A. Jones 《Journal of Polymer Science.Polymer Physics》2005,43(18):2433-2444
Deuterium solid echo line shapes were measured on deuterated poly(ethylene oxide) (d4PEO) in a blend with protonated poly(methyl methacrylate) to characterize chain dynamics of this component in the blend. Line shapes were observed as a function of temperature from 183 to 243 K and echo delay times from 10 to 100 μs on a blend containing 20 wt % d4PEO. The line shapes and the associated relative intensities were quantitatively interpreted in terms of segmental motion and libration. The results of the interpretation are compared to an earlier study of deuterium spin‐lattice relaxation times over the temperature range of 313 to 413 K. A combined interpretation of both sets of data is developed based on bimodal distribution of correlation times that are separated by about 2 orders of magnitude in time. The faster mode is 30% of the correlation function with a stretched exponent near one while the slower mode is characterized by an exponent of 0.5. The source of the bimodal character is not revealed by the line shape and relaxation data but is consistent with the presence of two glass transition temperatures in this miscible blend and anomalous translational diffusion of diethyl ether through the blend. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2433–2444, 2005 相似文献
1000.
Environmental Impacts on Spiking Properties in Hodgkin-Huxley Neuron with Direct Current Stimulus
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Based on the well accepted Hodgkin-Huxley neuron model, the neuronal intrinsic excitability is studied when the neuron is subject to varying environmental temperatures, the typical impact for its regulating ways. With computer simulation, it is found that altering environmental temperature can improve or inhibit the neuronal intrinsic excitability so as to influence the neuronal spiking properties. The impacts from environmental factors can be understood that,the neuronal spiking threshold is essentially influenced by the fluctuations in the environment. With the environmental temperature varying, burst spiking is realized for the neuronal membrane voltage because of the environment-dependent spiking threshold. This burst induced by changes in spiking threshold is different from that excited by input currents or other stimulus. 相似文献