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<jats:p>We discuss evolutions of nonlinear features in Richtmyer–Meshkov instability (RMI), which are known as spikes and bubbles. In single-phase RMI, the nonlinear growth has been extensively studied but the relevant investigation in multiphase RMI is insufficient. Therefore, we illustrate the dynamic coupling behaviors between gas phase and particle phase and then analyze the growth of the nonlinear features theoretically. A universal model is proposed to describe the nonlinear finger (spike and bubble) growth velocity qualitatively in multiphase RMI. Both the effects of gas and particles have been taken into consideration in this model. Further, we derive the analytical expressions of the nonlinear growth model in limit cases (equilibrium flow and frozen flow). A novel compressible multiphase particle-in-cell (CMP-PIC) method is used to validate the applicability of this model. Numerical finger growth velocity matches well with our model. The present study reveals that particle volume fraction, particle density and Stokes number are the three key factors, which dominate the interphase momentum exchange and further induce the unique property of multiphase RMI.</jats:p>

<jats:p>We present our experimental ablation results for partially overlapped dual nanosecond laser beams (PO-DB) on metal and glass surfaces. Numerical simulations are performed to evaluate the crater reduction potential of the PO-DB setup. Damage probability experiments proved the collaboration of two beams within the overlap region. Bright-field and three-dimensional profile measurements verify the reduced ablation area from the proposed PO-DB scheme. Laser-induced plasma is generated when transparent glass is ablated. Atomic emission of Na I (∼589.95 nm) shows comparable signal between the PO-DB set and the traditional single laser beam set. The proposed PO-DB ablation mechanism could also be applied to femtosecond laser systems.</jats:p>

<jats:p>A three-dimensional (3D) Burgers’ equation adopting perturbative methodology is derived to study the evolution of a shock wave with Landau quantized magnetic field in relativistic quantum plasma. The characteristics of a shock wave in such a plasma under the influence of magnetic quantization, relativistic parameter and degenerate electron density are studied with assistance of steady state solution. The magnetic field has a noteworthy control, especially on the shock wave’s amplitude in the lower range of the electron density, whereas the amplitude in the higher range of the electron density reduces remarkably. The rate of increase of shock wave potential is much higher (lower) with a magnetic field in the lower (higher) range of electron density. With the relativistic factor, the shock wave’s amplitude increases significantly and the rate of increase is higher (lower) for lower (higher) electron density. The combined effect of the increase of relativistic factor and the magnetic field on the strength of the shock wave, results in the highest value of the wave potential in the lower range of the degenerate electron density.</jats:p>

<jats:p>The incomplete decomposition product of metastable hydrazine (N<jats:sub>2</jats:sub>H<jats:sub>4</jats:sub>) instead of the energetically favorable ammonia (NH<jats:sub>3</jats:sub>) upon decompression is one drawback in applications of energetic material oligomeric hydronitrogens. We explore the stability of hydrazine molecules in hydrazine hydrate (N<jats:sub>2</jats:sub>H<jats:sub>4</jats:sub>·H<jats:sub>2</jats:sub>O) under pressure in diamond anvil cells (DACs) combined with <jats:italic>in situ</jats:italic> Raman spectroscopy and synchrotron x-ray diffraction (XRD) measurements. The results show that one NH<jats:sub>2</jats:sub> branch forms NH<jats:sub>3</jats:sub> group by hydrogen bonds between hydrazine and water molecules after the sample crystallizes at 3.2 GPa. The strengthening hydrogen bonds cause the torsion of hydrazine molecules and further dominate a phase transition at 7.2 GPa. Surprisingly, the NN single bonds are strengthened with increasing pressure, which keeps the hydrazine molecules stable up to the ultimate pressure of 36 GPa. Furthermore, the main diffraction patterns show continuous shift to higher degrees in the whole pressure range while some weak lines disappear above 8.2 GPa. The present peak-indexing results of the diffraction patterns with Materials Studio show that the phase transition occurs in the same monoclinic crystal system. Upon decompression, all of the hydrazine molecules extract from hydrazine hydrate crystal at 2.3 GPa, which may provide a new way to purify hydrazine from hydrate.</jats:p>

<jats:p>An analytic incremental model is proposed to predict the defect production upon cascade overlapping. By resolving the coupled annealing events during cascade overlapping, this model handles cascade overlapping with multiple pre-existing defects of different sizes and number densities. The model is first parameterized and then applied to bcc-Fe. The proposed model satisfyingly reproduces the defect production obtained by molecular dynamics simulations with various radiation damage levels and defect cluster size distributions. The present model provides an essential description of the primary source of radiation damage, especially for high dose irradiation, and could be used in conjunction with reactive diffusion models for better understanding of radiation damage.</jats:p>

<jats:p>The structural, thermal expansion, and magnetic properties of the Nd<jats:sub>2</jats:sub>Fe<jats:sub>16.5</jats:sub>Cr<jats:sub>0.5</jats:sub> compound are investigated by means of x-ray diffraction and magnetization measurements. The Nd<jats:sub>2</jats:sub>Fe<jats:sub>16.5</jats:sub>Cr<jats:sub>0.5</jats:sub> compound has a rhombohedral Th<jats:sub>2</jats:sub>Zn<jats:sub>17</jats:sub>-type structure. There exists a small negative thermal expansion resulting from a spontaneous magnetostriction in the magnetic state of the Nd<jats:sub>2</jats:sub>Fe<jats:sub>16.5</jats:sub>Cr<jats:sub>0.5</jats:sub> compound. The average thermal expansion coefficient is −1.06 × 10<jats:sup>−6</jats:sup>/K in a temperature range 299–394 K. The spontaneous magnetostrictive deformation and the Curie temperature are discussed.</jats:p>

<jats:p>We present the microscopic origin of the ferromagnetism of Fe<jats:sub>0.25</jats:sub>TaS<jats:sub>2</jats:sub> and its finite-temperature magnetic properties. The band structures of Fe<jats:sub>0.25</jats:sub>TaS<jats:sub>2</jats:sub> are first obtained by the first-principles calculations and it is found that both conventional and Dirac carriers coexist in metallic Fe<jats:sub>0.25</jats:sub>TaS<jats:sub>2</jats:sub>. Accordingly, considering the spin-orbit coupling of Fe 3<jats:italic>d</jats:italic> ion, we derive an effective Ruderman–Kittle–Kasuya–Yosida-type Hamiltonian between Fe spins in the presence of both the conventional parabolic-dispersion and the Dirac linear-dispersion carriers, which contains a Heisenberg-like, an Ising-like and an XY-like term. In addition, we obtain the ferromagnetic Curie temperature <jats:italic>T</jats:italic> <jats:sub>c</jats:sub> by using the cluster self-consistent field method. Our results could address not only the high ferromagnetic Curie temperature but also the large magnetic anisotropy in Fe<jats:sub> <jats:italic>x</jats:italic> </jats:sub>TaS<jats:sub>2</jats:sub>.</jats:p>

<jats:p>Thermoelectric properties of pure, Cd- and In-doped ZnSb are studied by first principles calculations of electronic structures and the semi-classical Boltzmann transport theory. The doping of Cd or In at the Zn lattice site slightly increases the lattice parameters due to the larger atomic radii of Cd and In compared with that of Zn. Cd or In doping also apparently increases the interatomic distances between the dopant atoms and the surrounding atoms. The power factor of n-type ZnSb is much larger than that of p-type ZnSb, indicating that n-type ZnSb has better thermoelectric performance than p-type ZnSb. After the doping of Cd or In, the power factor reduces mainly due to the decrease of the electrical conductivity. The temperature dependences of the Seebeck coefficient and the power factor of pure, Cd- and In-doped ZnSb are related to carrier concentrations.</jats:p>

<jats:p>We report an enhanced rejuvenation in hot-drawn micrometer metallic glassy wires (MG wires) with the size reduction. Compared to metallic glasses (MGs) in bulk form, the modulus and hardness for the micro-scale MG wires, tested by nanoindentation methods, are much lower and decrease with the decreasing size, with a maximum decrease of ∼26% in modulus and ∼17% in hardness. This pronounced rejuvenation is evidenced by the larger sub-<jats:italic>T</jats:italic> <jats:sub>g</jats:sub> relaxation enthalpy of the MG wires. The pronounced rejuvenation is physically related to the higher energy state induced by a combined effect of severely thermomechanical shearing and freezing the shear flow into a constrained small-volume region. Our results reveal that the internal states and properties of MGs can be dramatically changed by a proper modulation of temperature, flow stress and size.</jats:p>

<jats:p>Topological Weyl semimetal WTe<jats:sub>2</jats:sub> with large-scale film form has a promising prospect for new-generation spintronic devices. However, it remains a hard task to suppress the defect states in large-scale WTe<jats:sub>2</jats:sub> films due to the chemical nature. Here we significantly improve the crystalline quality and remove the Te vacancies in WTe<jats:sub>2</jats:sub> films by post annealing. We observe the distinct Shubnikov-de Haas quantum oscillations in WTe<jats:sub>2</jats:sub> films. The nontrivial Berry phase can be revealed by Landau fan diagram analysis. The Hall mobility of WTe<jats:sub>2</jats:sub> films can reach 1245 cm<jats:sup>2</jats:sup>V<jats:sup>−1</jats:sup>s<jats:sup>−1</jats:sup> and 1423 cm<jats:sup>2</jats:sup>V<jats:sup>−1</jats:sup>s<jats:sup>−1</jats:sup> for holes and electrons with the carrier density of 5 × 10<jats:sup>19</jats:sup> cm<jats:sup>−3</jats:sup> and 2 × 10<jats:sup>19</jats:sup> cm<jats:sup>−3</jats:sup>, respectively. Our work provides a feasible route to obtain high-quality Weyl semimetal films for the future topological quantum device applications.</jats:p>