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<jats:title>Abstract</jats:title> <jats:p>The linear behavior of the dominant unstable mode (m=2,n=1) and its high order harmonics (m=2n, n ≥ 2) are numerically investigated in a reversed magnetic shear cylindrical plasma with two q=2 rational surfaces on the basis of the non-reduced magnetohydrodynamics (MHD) equations. The results show that with low beta (ratio of plasma pressure to magnetic field pressure), the dominant mode is a classical double tearing mode (DTM). However, when the beta is sufficiently large, the mode is majorly driven by plasma pressure. In such case, both the linear growth rate and mode structures are strongly affected by pressure, while resistivity has very little effects. This means that the dominant mode undergoes a transition from DTM to pressure driven mode with the increase of pressure, which is consistent with the experimental results in ASDEX Upgrade. The simulations also show that the distance between two rational surfaces has an important influence on the pressure needed in mode transition. The larger the distance between two rational surfaces is, the larger pressure is needed for the mode transition. Motivated by the phenomena that the high-m modes may dominate over low-m modes at small inter-resonance distance, the high-m modes with different pressure and q profile are studied too.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>In this work, we have studied the nonlinear optical rectification (NOR) of spherical quantum dots (QDs) under Hulth´en plus Hellmann (HPH) confining potential with the external tuning elements. Energy and wavefunction have been determined with the help of the Nikiforov-Uvarov (NU) method. Expression for the NOR coefficient is derived by the density matrix theory. The results show that the applied external elements and internal parameters of this system have a strong influence on intraband nonlinear optical properties. It is hoped that this tuning of the nonlinear optical properties of GaAs/Ga<jats:sub>1-<jats:italic>x</jats:italic> </jats:sub>Al<jats:sub> <jats:italic>x</jats:italic> </jats:sub>As QDs can make a greater contribution to the preparation of new functional optical devices.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We study here the strong nonlinear optical dynamics of nanosecond pulsed Laguerre-Gaussian laser beams of high-order radial modes with zero orbital angular momentum propagating in the fullerene C<jats:sub>60</jats:sub> molecular medium. It is found that the spatiotemporal profile of the incident pulsed Laguerre-Gaussian laser beam is strongly reshaped during its propagating in the C<jats:sub>60</jats:sub> molecular medium. The centrosymmetric temporal profile of the incident pulse evolves gradually into a non-centrosymmetric meniscus shape, and the on axis pulse duration is clearly depressed. Furthermore, the field intensity is distinctly attenuated due to the field intensity dependent reverse saturable absorption, and clear optical power limiting behavior is observed for different orders of the input pulsed Laguerre-Gaussian laser beams before the takeover of the saturation effect, and the lower the order of the Laguerre-Gaussian beam the less the energy transmittance.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The effects of Nd doping on the microstructures and magnetic properties of Sm<jats:sub>1-x</jats:sub>Nd<jats:sub>x</jats:sub> (Co<jats:sub>0.695</jats:sub>Fe<jats:sub>0.2</jats:sub>Cu<jats:sub>0.08</jats:sub>Zr<jats:sub>0.025</jats:sub>)<jats:sub>7.2</jats:sub> (x=0, 0.3, 0.5, 0.7, 1.0) permanent magnets are studied. The SEM analysis of the solid solution state of the magnets shows that with the increase of Nd content, the distribution of elements becomes inhomogeneous and miscellaneous phase will be generated. Positive temperature coefficient of coercivity (<jats:italic>β</jats:italic>) appears in the x=0.3, 0.5 and 0.7 samples. The corresponding positive <jats:italic>β</jats:italic> temperature ranges are about 70-170 K, 60-260 K, 182-490 K for the samples with x=0.3, 0.5 and 0.7, respectively. Thermomagnetic analysis shows that spin-reorientation-transition (SRT) of the cell boundary phase is responsible for this phenomenon. On the basis of this discovery, a Sm<jats:sub>0.7</jats:sub>Nd<jats:sub>0.3</jats:sub> (Co<jats:sub>0.695</jats:sub>Fe<jats:sub>0.2</jats:sub>Cu<jats:sub>0.08</jats:sub>Zr<jats:sub>0.025</jats:sub>)<jats:sub>7.2</jats:sub> magnet possessing thermal stability with <jats:italic>β</jats:italic> ≈ -0.002 %/K at the temperature range of 150-200 K was obtained.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Recently, lanthanide-ion-doped luminescent materials have been extensively applied as optical thermometry probes due to their fast response, non-contact and high sensitivity properties. Basing on the different responses of two emissions to temperature, the fluorescence intensity ratio (FIR) technique can be executed and further estimate the sensitivities to assess the optical thermometry performances. In this study, we introduce different doping concentrations of Eu<jats:sup>3+</jats:sup> ions into negative thermal expansion material Sc<jats:sub>2</jats:sub>W<jats:sub>3</jats:sub>O<jats:sub>12</jats:sub>, accessing to the thermal enhanced luminescence from 373 to 548 K, and investigate the temperature sensing properties in detail. All samples exhibit good thermally enhanced luminescence behavior. The emission intensity of Sc<jats:sub>2</jats:sub>W<jats:sub>3</jats:sub>O<jats:sub>12</jats:sub>: 6 mol% Eu<jats:sup>3+</jats:sup> phosphors reaches at 147.8% of initial intensity at 473 K. As the Eu<jats:sup>3+</jats:sup> doping concentration increases, the resistance of the samples to thermal quenching decreases. The FIR technique based on the transitions <jats:sup>5</jats:sup>D<jats:sub>0</jats:sub>→<jats:sup>7</jats:sup>F<jats:sub>1</jats:sub> (592 nm) and <jats:sup>5</jats:sup>D<jats:sub>0</jats:sub>→<jats:sup>7</jats:sup>F<jats:sub>2</jats:sub> (613 nm) of Eu<jats:sup>3+</jats:sup> ions demonstrate a maximum relative temperature sensitivity of 3.063% K<jats:sup>-1</jats:sup> at 298 K for Sc<jats:sub>2</jats:sub>W<jats:sub>3</jats:sub>O<jats:sub>12</jats:sub>: 6 mol% Eu<jats:sup>3+</jats:sup> phosphors. The sensitivity of sample decreases with the increase of Eu<jats:sup>3+</jats:sup> concentration. Benefiting from the thermal enhanced luminescence performance and good temperature sensing properties, the Sc<jats:sub>2</jats:sub>W<jats:sub>3</jats:sub>O<jats:sub>12</jats:sub>: Eu<jats:sup>3+</jats:sup> phosphors can be applied as optical thermometers.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We investigate a (2+1)-dimensional shallow water wave equation and describe its nonlinear dynamical behaviors in physics. Based on the <jats:italic>N</jats:italic>-soliton solutions, the higher-order fissionable and fusionable waves, fissionable or fusionable waves mixed with soliton molecular and breather waves can be obtained by various constraints of special parameters. At the same time, by the long wave limit method, the interaction waves between fissionable or fusionable waves with higher-order lumps are acquired. Combined with the dynamic figures of the waves, the properties of the solution are deeply studied to reveal the physical significance of the waves.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Quantum secret sharing (QSS) is a typical multi-party quantum communication mode, in which the key sender splits a key into several parts and the participants can obtain the key by cooperation. Measurement-device-independent quantum secret sharing (MDI-QSS) is immune to all possible attacks from measurement devices and can greatly enhance QSS’s security in practical application. However, previous MDI-QSS’s key generation rate is relatively low. In our paper, we adopt the spatial-mode-polarization hyper-encoding technology in the MDI-QSS, which can increase single photon’s channel capacity. Meanwhile, we use the cross-Kerr nonlinearity to realize the complete hyperentangled Greenberger-Horne-Zeilinger state analysis. Both above factors can increase MDI-QSS’s key generation rate by about 10<jats:sup>3</jats:sup>. The proposed hyper-encoded MDI-QSS protocol may be useful for future multiparity quantum communication application.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>In this paper, a partially coherent beam called radially polarized multi-Gaussian Schell-model power-exponent-phase vortex beam is introduced. Both the analytical formula of the beam propagating through the high numerical aperture objective lens based on the vectorial diffraction theory, and the cross-spectral density matrix of the beam in the focal region are derived. Then, the tight focusing characteristics of partially coherent radially polarized power-exponent-phase vortex beam are studied numerically, and the intensity distribution, degree of polarization and coherence of the beams in the focusing region of different topological charge, power order, beam index and coherence width are analyzed in detail. The results show that the contour of the spot becomes clearer and smoother with the increase of beam index, and the focal fields of different structures including the flattened beam can be obtained by changing the coherence width. In addition, by changing the topological charge and power order, the intensity can gather to a point along the ring. These unique properties will have potential applications in particle capture and manipulation, especially in the manipulation of irregular particles.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>In the paper, we investigated the properties of the excess charge (electron, hole) introduced into a two–strand biomolecule. We considered the possibility that the stable soliton excitation can be formed due to the interaction of the excess charge with the phonon subsystem. The influence of the overlap of the molecular orbitals between adjacent structure elements of the macromolecular chain on the soliton properties was discussed. Special attention was paid to the influence of the overlapping of the molecular orbitals between structure elements placed on the different chains. Using the literature values of the basic energy parameters of the two–chain biomolecular structures, possible types of soliton solutions were discussed.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Exploring low-cost and high-performance catalysts for oxygen evolution reaction (OER) remains a great challenge. Iridium-based perovskite oxide has large potential in OER because of its intrinsic activity and outstanding physicochemical properties. In this study, Iridium-doped strontium titanate (Ir-STO) solution was brushed on a Ti sheet by the traditional method to obtain the Ir-STO/Ti electrodes after being calcined at a high temperature. The microstructure and electrocatalysis properties of the Ir-STO are further modified by a facile and scalable NH<jats:sub>3</jats:sub>-plasma strategy. In addition to the doping of Ir, the NH<jats:sub>3</jats:sub> plasma treatment further results in N-doping into Ir-STO, which enriches active species and causes oxygen vacancies near doped sites. The resulting N, Ir-STO/Ti electrode reveals excellent acidic OER activity with the lowest overpotential of 390 mV at 10 mA/cm<jats:sup>2</jats:sup> and the smallest Tafel slope of 140 mV/dec after 10 min plasma treatment. Therefore, the great potential of activated N, Ir-STO/Ti is regarded as a catalyst for the OER and opens up new opportunities for other perovskite catalysts via NH<jats:sub>3</jats:sub> plasma treatment.</jats:p>