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<jats:p>Brownian motors and self-phoretic microswimmers are two typical micromotors, for which thermal fluctuations play different roles. Brownian motors utilize thermal noise to acquire unidirectional motion, while thermal fluctuations randomize the self-propulsion of self-phoretic microswimmers. Here we perform mesoscale simulations to study a composite micromotor composed of a self-thermophoretic Janus particle under a time-modulated external ratchet potential. The composite motor exhibits a unidirectional transport, whose direction can be reversed by tuning the modulation frequency of the external potential. The maximum transport capability is close to the superposition of the drift speed of the pure Brownian motor and the self-propelling speed of the pure self-thermophoretic particle. Moreover, the hydrodynamic effect influences the orientation of the Janus particle in the ratched potential, hence also the performance of the composite motor. Our work thus provides an enlightening attempt to actively exploit inevitable thermal fluctuations in the implementation of the self-phoretic microswimmers.</jats:p>

<jats:p>We present the first simulation results of a multi-shell target ignition driven by Z-pinch dynamic hohlraum radiation pulse. The radiation pulse is produced with a special Z-pinch dynamic hohlraum configuration, where the hohlraum is composed of a single metal liner, a low-Z plastic foam, and a high-Z metallic foam. The implosion dynamics of a hohlraum and a multi-shell target are investigated separately by the one-dimensional code MULTI-IFE. When the peak drive current is 50 MA, simulations suggest that an x-ray pulse with nearly constant radiation temperature (∼ 310 eV) and a duration about 9 ns can be obtained. A small multi-shell target with a radius of 1.35 mm driven by this radiation pulse is able to achieve volumetric ignition with an energy gain (<jats:italic>G</jats:italic>) about 6.19, where <jats:italic>G</jats:italic> is the ratio of the yield to the absorbed radiation. Through this research, we better understand the effects of non-uniformities and hydrodynamics instabilities in Z-pinch dynamic hohlraum.</jats:p>

<jats:p>Plasma density and temperature can be diagnosed by x-ray line emission measurement with crystal, and bent crystals such as von Hamos and Hall structures are proposed to improve the diffraction brightness. In this study, a straightforward solution for the focusing schemes of flat and bent crystals is provided. Simulations ith XOP code are performed to validate the analytical model, and good agreements are achieved. The von Hamos or multi-cone crystal can lead to several hundred times intensity enhancements for a 200 upmu mplasma source. This model benefits the applications of the bent crystals.</jats:p>

<jats:p>The dislocation slip behaviors in GaN bulk crystal are investigated by nanoindentation, the dislocation distribution patterns formed around an impress are observed by cathodoluminescence (CL) and cross-sectional transmission electron microscope (TEM). Dislocation loops, vacancy luminescence, and cross-slips show hexagonal symmetry around the 〈11-20〉 and 〈1-100〉 direction on <jats:italic>c</jats:italic>-plane. It is found that the slip planes of dislocation in GaN crystal are dominated in {0001} basal plane and {10-11} pyramid plane. According to the dislocation intersection theory, we come up with the dislocation formation process and the related mechanisms are discussed.</jats:p>

<jats:p>Molecular dynamic analysis was performed on pure and doped (by Re, Ru, Co or W) Ni at 300 K using the embedded-atom-method (EAM) potentials to understand the crack formation of the doped Ni matrix in the (010)[001] orientation. When Ni was doped with Re, Ru, and W, the matrix demonstrated increased lattice trapping limits and, as a result, improved the mechanical properties. Consequently, this prevented the bond breakage at the crack tips and promoted crack healing. The average atomic and surface energy values increased when Re, Ru, and W were added. Analysis of these energy increase helpedus to understand the influence these elements had on the lattice trapping limits. The fracture strength of the Ni matrixat 300 K increased because of the formation of the stronger Ni–Re, Ni–Ru, and Ni–W bonds. At the same time, doping the Ni matrix with Co did not demonstrate any strengthening effects because of the formation of Co–Ni bonds, which are weaker than the Ni–Ni bonds. Out of all dopants tested in this work, Ni doping with W showed the best results.</jats:p>

<jats:p>The III–V alloys and doping to tune the bandgap for solar cells and other optoelectronic devices has remained a hot topic of research for the last few decades. In the present article, the bandgap tuning and its influence on optical properties of In<jats:sub>1–<jats:italic>x</jats:italic> </jats:sub>Ga<jats:sub> <jats:italic>x</jats:italic> </jats:sub>N/P, where (<jats:italic>x</jats:italic> = 0.0, 0.25, 0.50, 0.75, and 1.0) alloys are comprehensively analyzed by density functional theory based on full-potential linearized augmented plane wave method (FP-LAPW) and modified Becke and Johnson potentials (TB-mBJ). The direct bandgaps turn from 0.7 eV to 3.44 eV, and 1.41 eV to 2.32 eV for In<jats:sub>1–<jats:italic>x</jats:italic> </jats:sub>Ga<jats:sub> <jats:italic>x</jats:italic> </jats:sub>N/P alloys, which increases their potentials for optoelectronic devices. The optical properties are discussed such as dielectric constants, refraction, absorption, optical conductivity, and reflection. The light is polarized in the low energy region with minimum reflection. The absorption and optical conduction are maxima in the visible region, and they are shifted into the ultraviolet region by Ga doping. Moreover, static dielectric constant <jats:italic>ε</jats:italic> <jats:sub>1</jats:sub>(0) is in line with the bandgap from Penn’s model.</jats:p>

<jats:p>Bi doped n-type SnSe thin films were prepared by chemical vapor deposition (CVD) and their structure and thermoelectric properties were studied. The x-ray diffraction patterns, x-ray photoelectron spectroscopy, and microscopic images show that the prepared SnSe thin films were composed of pure SnSe crystals. The Seebeck coefficients of the Bi-doped SnSe were greatly improved compared to that of undoped SnSe thin films. Specifically, Sn<jats:sub>0.99</jats:sub>Bi<jats:sub>0.01</jats:sub>Se thin film exhibited a Seebeck coefficient of –905.8 μV⋅K<jats:sup>−1</jats:sup> at 600 K, much higher than 285.5 μV⋅K<jats:sup>−1</jats:sup> of undoped SnSe thin film. Further first-principles calculations reveal that the enhancement of the thermoelectric properties can be explained mainly by the Fermi level lifting and the carrier pockets increasing near the Fermi level due to Bi doping in the SnSe samples. Our results suggest the potentials of the Bi-doped SnSe thin films in thermoelectric applications.</jats:p>

<jats:p>The interaction of single water droplet impacting on immiscible liquid surface was focused with the temperature varying from 50 °C to 210 °C. The impact behavior is recorded with a high-speed camera running at 2000 frames per second. It is found that droplet diameter, oil temperature, and Weber number have important influences on impact behaviors. Three typical phenomena, including penetration, crater-jet, and crater-jet–secondary jet, were observed. Penetration only occurs when the Weber number is below 105. With Weber number increasing to 302, the jet begins to appear. Moreover, to gain deeper physical insight into the crater formation and jet formation, the energy of droplet impingement onto the liquid pool surface was estimated. The oil temperature has a significant effect on the energy conversion efficiency. High temperature is beneficial to improve energy conversion efficiency.</jats:p>

<jats:p>The construction of van der Waals (vdW) heterostructures by stacking different two-dimensional layered materials have been recognised as an effective strategy to obtain the desired properties. The 3N-doped graphdiyne (N-GY) has been successfully synthesized in the laboratory. It could be assembled into a supercapacitor and can be used for tensile energy storage. However, the flat band and wide forbidden bands could hinder its application of N-GY layer in optoelectronic and nanoelectronic devices. In order to extend the application of N-GY layer in electronic devices, MoS<jats:sub>2</jats:sub> was selected to construct an N-GY/MoS<jats:sub>2</jats:sub> heterostructure due to its good electronic and optical properties. The N-GY/MoS<jats:sub>2</jats:sub> heterostructure has an optical absorption range from the visible to ultraviolet with a absorption coefficient of 10<jats:sup>5</jats:sup> cm<jats:sup>−1</jats:sup>. The N-GY/MoS<jats:sub>2</jats:sub> heterostructure exhibits a type-II band alignment allows the electron-hole to be located on N-GY and MoS<jats:sub>2</jats:sub> respectively, which can further reduce the electron-hole complexation to increase exciton lifetime. The power conversion efficiency of N-GY/MoS<jats:sub>2</jats:sub> heterostructure is up to 17.77%, indicating it is a promising candidate material for solar cells. In addition, the external electric field and biaxial strain could effectively tune the electronic structure. Our results provide a theoretical support for the design and application of N-GY/MoS<jats:sub>2</jats:sub> vdW heterostructures in semiconductor sensors and photovoltaic devices.</jats:p>

<jats:p>Ultrathin van der Waals (vdW) magnets provide a possibility to access magnetic ordering in the two-dimensional (2D) limit, which are expected to be applied in the spintronic devices. Raman spectroscopy is a powerful characterization method to investigate the spin-related properties in 2D vdW magnets, including magnon and spin–lattice interaction, which are hardly accessible by other optical methods. In this paper, the recent progress of various magnetic properties in 2D vdW magnets studied by Raman spectroscopy is reviewed, including the magnetic transition, spin-wave, spin–lattice interaction, symmetry tuning induced by spin ordering, and nonreciprocal magneto-phonon Raman scattering.</jats:p>