The evolution of spatial solitons in the photovoltaic photorefractive crystal can be governed by the specific coupled nonlinear Schrödinger equations. Under the photovoltaic field with the external ...bias field, the coupled cn–sn-type periodic wave solution and the corresponding photorefractive bright–dark soliton pair were constructed to describe the evolution of beam. The influence of the external bias field on solitonic dynamics is analyzed. In the photovoltaic crystal, coupled sn–cn-type, sn–dn-type periodic wave solutions, solution constructed by products of elliptic functions and the corresponding dark–bright soliton pair and coupled double-peaked soliton solutions are found to describe the evolution of a spatial-phase-modulated photovoltaic soliton and a non-phase-modulated beam.
Point positioning of a signal source is feasible if it is not far from the sensors and direction of arrival (DOA) localization is only applicable if it is distant. Point positioning and DOA ...localization employ different estimation models and prior knowledge about the source range is often not available to decide which model is appropriate. This paper introduces the modified polar representation to unify the localization of a source using angle of arrival (AOA) regardless if it is near or far. From the Gaussian AOA measurements, we utilize the hybrid Bhattacharyya-Barankin (HBB) bound to illustrate it is not possible to obtain the Cartesian coordinates of a distant source when applying the near-field model, and derive the DOA bias of a not so distant source when using the far-field model. An iterative maximum likelihood estimator (MLE) is next derived under the modified polar representation with a single model, where the HBB bound confirms the stable behavior of the estimator regardless it is near or far. The algorithm yields a position if the source is close and a DOA if it is distant. A preliminary solution to initialize the MLE using semidefinite relaxation is also proposed. The HBB bound, the analysis and the algorithm are extended for hybrid AOA-TDOA localization.
In China, shi hu (stems of Dendrobium chrysotoxum Lindl, D. fimbriatum Hook. D. huoshanense Z.Z. Tang & S.J. Cheng, or D. nobile Lindl) and tie pi shi hu (stems of D. officinale Kimura et Migo) are ...famous traditional medicines and are listed in the Chinese Pharmacopoeia. However, the leaves of these Dendrobium plants are largely discarded.
To better utilize Dendrobium leaves, we summarize their traditional uses, chemical constituents, pharmacological activities, and toxicological effects.
“Orchidaceae”, “Dendrobium”, “leaf”, “traditional use”, and “ethnobotany” were used as search terms to screen the literature. Cited references were collected between 1960 and 2020 from the Web of Science, China National Knowledge Internet (CNKI), SciFinder, and Google Scholar, primarily in English and Chinese.
Traditional uses of leaves from 16 Dendrobium species were identified in the literature. The major uses of Dendrobium leaves include treatments for dermatologic disorders, metabolic syndromes, nervous system disorders, and musculoskeletal system disorders. More than 50 chemical compounds have been identified in the leaves of 10 Dendrobium species, which primarily include flavonoids, bibenzyls, coumarins, N-containing compounds, and polysaccharides. Antihyperlipidemia, antihypertensive, antihyperuricemia, anti-inflammatory, antimicrobial, antioxidant, cytotoxic and antitumor, hepatoprotective, immunomodulatory, lipase-inhibitory, and/or tyrosinase-inhibitory activities have been reported for the leaves of six Dendrobium species. D. officinale leaves have been shown to exhibit no reproductive toxicity against male rats, while D. speciosum Sm. leaves have been observed to exhibit slight genotoxicity in an in vitro study. Among Dendrobium species, D. officinale leaves are the most widely studied.
D. officinale leaves represent a good example of the utilization of leaf resources of the Dendrobium genus. In the future, more extensive research for the development of Dendrobium leaves is needed.
A planting base and collected leaves of Dendrobium officinale in Yunnan, China. Display omitted
We use the physics-informed neural network to solve a variety of femtosecond optical soliton solutions of the high-order nonlinear Schrödinger equation, including one-soliton solution, two-soliton ...solution, rogue wave solution, W-soliton solution and M-soliton solution. The prediction error for one-soliton, W-soliton and M-soliton is smaller. As the prediction distance increases, the prediction error will gradually increase. The unknown physical parameters of the high-order nonlinear Schrödinger equation are studied by using rogue wave solutions as data sets. The neural network is optimized from three aspects including the number of layers of the neural network, the number of neurons, and the sampling points. Compared with previous research, our error is greatly reduced. This is not a replacement for the traditional numerical method, but hopefully to open up new ideas.
We consider a (
2
+
1
)-dimensional nonautonomous-coupled nonlinear Schrödinger equation, which includes the partially nonlocal nonlinearity under linear and harmonic potentials. Via a projecting ...expression between nonautonomous and autonomous equations, and utilizing the bilinear method and Darboux transformation method, we find diversified exact solutions. These solutions contain the nonlocal rogue wave and Akhmediev or Ma breather solutions, and the combined solution which describes a rogue wave superposed on an Akhmediev or Ma breather. By adjusting values of diffraction, width and phase chirp parameters of wave, the maximum value of the accumulated time can be modulated. When we compare the maximum value of the accumulated time with that of the excitation position parameters, we study the management of scalar and vector rogue waves, such as the excitations of full shape, early shape and climax shape for rogue waves.
Under parity-time symmetric potentials, different-order nonlinearities such as cubic, quintic and septimal nonlinearities, altogether with their combinations and second-order and fourth-order ...dispersions/diffractions are simultaneously considered to form three-dimensional optical solitons. Based on some high-order nonlinear Schrödinger equations, three-dimensional analytical optical soliton solutions are found. In the defocusing cubic nonlinear case, three-dimensional optical soliton without fourth-order diffraction/dispersion is stable than that with fourth-order diffraction/dispersion. However, in the defocusing cubic and focusing quintic nonlinear case, the stability situation of soliton is just on the contrary. Among all combinations of nonlinearity, the stability of three-dimensional optical soliton in the cubic-quintic nonlinear case is better than that in the cubic nonlinear case, but worse than that in the cubic-quintic-septimal nonlinear case. In the quintic-septimal nonlinear case, three-dimensional optical soliton is unstable and will collapse ultimately.
TDOA localization requires the knowledge if the source is in the near-field or far-field, for the purpose to decide using the curved wavefront model that enables point positioning or the linear ...wavefront model that provides only the DOA. Such prior knowledge is often not available in practice. The far-field model can cause a considerable amount of DOA bias if the source is not sufficiently distant from the sensor array. This paper proposes a unified model to locate a source irrespective of whether it is in the near field, the far field or in between. The proposed model represents the source location by the direction and the inverse-range. It yields the unique coordinate if the source is near or the DOA if it is distant. We developed the Maximumm Likelihood Estimator for the proposed model through the Gauss-Newton iteration and semidefinite relaxation. We analyze the proposed model using the Hybrid Bhattacharyya-Barankin bound and show that the proposed model does not have the thresholding effect as the source range increases, validating that there is no need to resort to the far-field model even if the source range is large. We also perform bias analysis and elaborate a benefit of the proposed approach in reducing the DOA bias as compared to the far-field model.
•Influence of the higher-order nonlinearity on soliton pulse.•Influence of the higher-order dispersion term on output spectrum.•Soliton evolution with soliton splitting.•Propagation properties of M ...solitons.
The complex Swift-Hohenberg equation (CSHE) has been widely studied in recent years. It is a more real model in the mode-locked fiber laser with the saturable absorber due to the addition of the diffraction term compared with the complex Ginzburg-Landau equation. In this work, the dynamics process of the traditional soliton and M−type soliton pulses in the mode-locked fiber laser is demonstrated based on the CSHE model with higher-order nonlinear effects. The results show that with the increase of the small signal gain coefficient, the number of soliton molecules adds gradually. Under the same transmission conditions, the transmission of M−type solitons in the laser are more stable than that of single solitons. By adding the self-steepening effect, it can be found that the time-domain shift due to higher-order dispersion effects is compensated. The self-frequency shift effect caused by the Raman scattering can produce not only time domain shift, but also frequency domain shift. Moreover, the addition of higher-order diffraction term can describe the spectral response of multiple peaks, and makes the pulse spectrum show the asymmetric propagation in the transmission process. Finally, the increase of the length of the single-mode fiber on the right side of the gain fiber in the optical circuit will not only shift the center position of the output pulse backward, but also make the pulse energy show a ladder type downward trend.
A
bstract
Positivity bounds are powerful tools to constrain effective field theories. Utilizing the partial wave expansion in the dispersion relation and the full crossing symmetry of the scattering ...amplitude, we derive several sets of generically nonlinear positivity bounds for a generic scalar effective field theory: we refer to these as the
P Q
,
D
su
,
D
stu
and
D
¯
stu
bounds. While the
PQ
bounds and
D
su
bounds only make use of the
s
↔
u
dispersion relation, the
D
stu
and
D
¯
stu
bounds are obtained by further imposing the
s
↔
t
crossing symmetry. In contradistinction to the linear positivity for scalars, these inequalities can be applied to put upper and lower bounds on Wilson coefficients, and are much more constraining as shown in the lowest orders. In particular we are able to exclude theories with soft amplitude behaviour such as weakly broken Galileon theories from admitting a standard UV completion. We also apply these bounds to chiral perturbation theory and we find these bounds are stronger than the previous bounds in constraining its Wilson coefficients.
Parallel control and management have been proposed as a new mechanism for conducting operations of complex systems, especially those that involved complexity issues of both engineering and social ...dimensions, such as transportation systems. This paper presents an overview of the background, concepts, basic methods, major issues, and current applications of Parallel transportation Management Systems (PtMS). In essence, parallel control and management is a data-driven approach for modeling, analysis, and decision-making that considers both the engineering and social complexity in its processes. The developments and applications described here clearly indicate that PtMS is effective for use in networked complex traffic systems and is closely related to emerging technologies in cloud computing, social computing, and cyberphysical-social systems. A description of PtMS system architectures, processes, and components, including OTSt, Dyna CAS, aDAPTS, iTOP, and TransWorld is presented and discussed. Finally, the experiments and examples of real-world applications are illustrated and analyzed.
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