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<jats:p>In the framework of nonlinear wave optics, we report the evolution process of a dipole breathing wave in lossy nonlocal nonlinear media based on the nonlocal nonlinear Schrödinger equation. The analytical expression of the dipole breathing wave in such a nonlinear system is obtained by using the variational method. Taking advantage of the analytical expression, we analyze the influences of various physical parameters on the breathing wave propagation, including the propagation loss and the input power on the beam width, the beam intensity, and the wavefront curvature. Also, the corresponding analytical solutions are obtained. The validity of the analysis results is verified by numerical simulation. This study provides some new insights for investigating beam propagation in lossy nonlinear media</jats:p>

<jats:p>We demonstrate a new management of multi-stage optical parametric generator (OPG) and amplifier (OPA) to obtain high-energy picosecond sources with high beam quality. The setup of multi-stage OPG-OPA requires mode-matching between the pump beam and the stable mode of the OPG-OPA. In a proof-of-principle experiment, the single-pass multi-stage OPG-OPA consists of three walk-off compensated KTP crystal pairs and two lenses, pumped by an 86 ps, 1064 nm 10 kHz picosecond laser. The signal light at ∼ 1.77 μ m has an average output power of 502 mW with record energy up to 50.2 μ J. The beam quality factor of the signal light can be improved to <jats:inline-formula> <jats:tex-math><?CDATA ${M}_{x}^{2}\times {M}_{y}^{2}=1.87\times 2.16$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msubsup> <mml:mi>M</mml:mi> <mml:mi>x</mml:mi> <mml:mn>2</mml:mn> </mml:msubsup> <mml:mo>×</mml:mo> <mml:msubsup> <mml:mi>M</mml:mi> <mml:mi>y</mml:mi> <mml:mn>2</mml:mn> </mml:msubsup> <mml:mo>=</mml:mo> <mml:mn>1.87</mml:mn> <mml:mo>×</mml:mo> <mml:mn>2.16</mml:mn> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_31_1_014204_ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> after filtering out about 40% signal power. To the best of our knowledge, it is the first picosecond single-pass multi-stage OPG-OPA pumped at kHz regime.</jats:p>

<jats:p>Thermally induced apoptosis for tumors depends mainly on the intrinsic characteristics of biological tissues as well as treatment temperature profile during magnetic hyperthermia. Further, treatment temperature distribution inside tumor depends on the injection behavior of irregular tumors, such as the injection dose and the injection location of nanofluids. In order to improve the treatment effect, the simulated annealing algorithm is adopted in this work to optimize the nanofluid injection behavior, and the improved Arrhenius model is used to evaluate the malignant ablations for three typical malignant tumor cell models. In addition, both the injection behavior optimization and the mass diffusion of nanofluid are both taken into consideration in order to improve the treatment effect. The simulation results demonstrate that the injection behavior can be optimized effectively by the proposed optimization method before therapy, the result of which can also conduce to improving the thermal apoptosis possibility for proposed typical malignant cells. Furthermore, an effective approach is also employed by considering longer diffusion duration and correct power dissipation at the same time. The results show that a better result can then be obtained than those in other cases when the power dissipation of MNPs is set to be <jats:italic>Q</jats:italic> <jats:sub>MNP</jats:sub> = 5.4 × 10<jats:sup>7</jats:sup> W·m<jats:sup>3</jats:sup> and the diffusion time is 16 h.</jats:p>

<jats:p>Molecular dynamics simulations were used to investigate the influence of pressure on the structural properties and dynamics of magnesium (Mg) during rapid solidification. The dynamics analysis revealed that, with an increase in pressure, the dynamics of Mg melt slowed down sharply and the dynamical heterogeneities increased, leading to a denser structure. Atom-level structural analysis using the cluster-type index method suggested that the predominant structure transformed from hexagonal closed-packed to face-centered cubic with increasing pressure from 0 GPa to 5 GPa, and then transformed to the A15 complex crystal structure as the pressure increased above 10 GPa. In addition, the nature of polymorph selection was investigated by analyzing the phonon dispersion of Mg under different pressures. These findings provide a novel insight into polymorphic transitions of Mg under pressure and guide the selection of Mg polymorphs for practical applications.</jats:p>

<jats:p>We propose a scheme to realize the <jats:italic>SU(3)</jats:italic> spin–orbit coupled three-component fermions in an one-dimensional optical lattice. The topological properties of the single-particle Hamiltonian are studied by calculating the Berry phase, winding number and edge state. We also investigate the effects of the interaction on the ground-state topology of the system, and characterize the interaction-induced topological phase transitions, using a state-of-the-art density-matrix renormalization-group numerical method. Finally, we show the typical features of the emerging quantum phases, and map out the many-body phase diagram between the interaction and the Zeeman field. Our results establish a way for exploring novel quantum physics induced by the SOC with <jats:italic>SU</jats:italic>(<jats:italic>N</jats:italic>) symmetry.</jats:p>

<jats:p>Mechanoresponsive luminescent (MRL) materials have drawn extensive concern due to their potential applications in mechanical sensors, memory chips, and security inks; especially these possessing high emission efficiency. In this work, we found trans-stilbene crystal exhibited two different pressure-induced emission enhancement (PIEE) behaviors at different pressure areas. The structural characterizations combined with density functional theory calculation indicate that the first emission enhancement was due to the decrease of nonradiation transition by the weaken of energy exchange process between atoms and lattice. And the second emission enhancement was attributed to the strengthen of C–H…C interactions from the non-planarization comformation. The results regarding the mechanoresponsive behavior of trans-stilbene offered a deep insight into PIEE from the structural point of view, which will facilitate the design of and search for high-performance MRL materials.</jats:p>

<jats:p>Ca<jats:sub>12</jats:sub>Al<jats:sub>14</jats:sub>O<jats:sub>33</jats:sub> (C12A7) and Y<jats:sub>0.02</jats:sub>Ca<jats:sub>11.98</jats:sub>Al<jats:sub>14</jats:sub>O<jats:sub>33</jats:sub> (Y-C12A7) single crystals were grown by using the traveling-solvent floating zone (TSFZ) method. The temperature was increased to avoid the bubbles and cracks which may be formed during the preparation of the ingot material. We have started with the flux higher than the normal to avoid the bubbles and make good treatment for the solid-liquid interface. The structures of both Ca<jats:sub>12</jats:sub>Al<jats:sub>14</jats:sub>O<jats:sub>33</jats:sub> (C12A7) and Y<jats:sub>0.02</jats:sub>Ca<jats:sub>11.98</jats:sub>Al<jats:sub>14</jats:sub>O<jats:sub>33</jats:sub> (Y-C12A7) were studied by using x-ray diffraction (XRD). Optical properties for C12A7 and Y-C12A7 single crystals have been studied in order to determine the optical parameters such as optical energy gap (<jats:italic>E</jats:italic> <jats:sub>g</jats:sub>), refractive index <jats:italic>n</jats:italic>, oscillating energy (<jats:italic>E</jats:italic> <jats:sub>o</jats:sub>), dispersion energy (<jats:italic>E</jats:italic> <jats:sub>d</jats:sub>), volume energy loss function (VELF), and surface energy loss function (SELF). Finally, a new result for these samples is that the third-order nonlinear optical susceptibility (<jats:italic>χ</jats:italic> <jats:sup>(3)</jats:sup>) was determined. The results have been discussed with effect of Y-doping on the C12A7 single crystals for optical and industrial applications.</jats:p>

<jats:p>The experimental observation of long-lived quantum coherence in the excitation energy transfer (<jats:bold>EET</jats:bold>) process of the several photosynthetic light-harvesting complexes at low and room temperatures has aroused hot debate. It challenges the common perception in the field of complicated pigment molecular systems and evokes considerable theoretical efforts to seek reasonable explanations. In this work, we investigate the coherent exciton dynamics of the phycoerythrin 545 (<jats:bold>PE545</jats:bold>) complex. We use the dissipation equation of motion to theoretically investigate the effect of the local pigment vibrations on the population transfer process. The result indicates that the realistic local pigment vibrations do assist the energy transmission. We demonstrate the coherence between different pigment molecules in the <jats:bold>PE545</jats:bold> system is an essential ingredient in the <jats:bold>EET</jats:bold> process among various sites. The coherence makes the excitation energy delocalized, which leads to the redistribution of the excitation among all the chromophores in the steady state. Furthermore, we investigate the effects of the complex high-frequency spectral density function on the exciton dynamics and find that the high-frequency Brownian oscillator model contributes most to the exciton dynamic process. The discussions on the local pigment vibrations of the Brownian oscillator model suggest that the local heterogeneous protein environments and the effects of active vibration modes play a significant role in coherent energy transport.</jats:p>

<jats:p>This paper details the design and simulation of a novel low-loss four-bit reconfigurable bandpass filter that integrates microelectromechanical system (MEMS) switches and comb resonators. A T-shaped reconfigurable resonator is reconfigured in a ‘one resonator, multiple MEMS switches’ configuration and used to gate the load capacitances of comb resonators so that a multiple-frequency filtering function is realized within the 7–16 GHz frequency range. In addition, the insertion loss of the filter is less than 1.99 dB, the out-of-band rejection is more than 18.30 dB, and the group delay is less than 0.25 ns. On the other hand, the size of this novel filter is only 4.4 mm × 2.5 mm × 0.4 mm. Our results indicate that this MEMS reconfigurable filter, which can switch 16 central frequency bands through eight switches, achieves a low insertion loss compared to those of traditional MEMS filters. In addition, the advantages of small size are obtained while achieving high integration.</jats:p>

<jats:p>Opinion dynamics models based on the multi-agent method commonly assume that interactions between individuals in a social network result in changes in their opinions. However, formation of public opinion in a social network is a macroscopic statistical result of opinions of all expressive individuals (corresponding to silent individuals). Therefore, public opinion can be manipulated not only by changing individuals’ opinions, but also by changing their states of expression (or silence) which can be interpreted as the phenomenon “spiral of silence” in social psychology. Based on this theory, we establish a “dual opinion climate” model, involving social bots and mass media through a multi-agent method, to describe mechanism for manipulation of public opinion in social networks. We find that both social bots (as local variables) and mass media (as a global variable) can interfere with the formation of public opinion, cause a significant superposition effect when they act in the same direction, and inhibit each other when they act in opposite directions.</jats:p>