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<jats:p>The shear-horizontal (SH) waves excited by the shear source in a borehole are easy to analyze due to the simple waveform. The borehole-side structures make the formation properties discontinuous. We consider a cylindrical double layer structure and study the borehole shear-horizontal and transverse-electric (SH-TE) seismoelectric waves. We first derive the expressions of the basic field quantities, and simulate the acoustic field and electric field using the real axis integral method. Compared with the wave fields of an infinitely homogeneous porous medium outside the borehole, the cylindrical layered structure makes the multi-mode cylindrical Love waves and their accompanying electric fields excited. Next, in order to study the interface response law of the inducing electric fields, we use the secant integral method to calculate the interface converted electromagnetic waves and analyze the causes of each component. It is found that an interface response occurs each time the SH wave impinges the interface in the layered porous medium. The results show that the SH-TE mode has a potential application for borehole-side interface detection in geophysical logs.</jats:p>

<jats:p>The main challenge in bone ultrasound imaging is the large acoustic impedance contrast and sound velocity differences between the bone and surrounding soft tissue. It is difficult for conventional pulse-echo modalities to give accurate ultrasound images for irregular bone boundaries and microstructures using uniform sound velocity assumption rather than getting <jats:italic>a prior</jats:italic> knowledge of sound speed. To overcome these limitations, this paper proposed a frequency-domain full-waveform inversion (FDFWI) algorithm for bone quantitative imaging utilizing ultrasonic computed tomography (USCT). The forward model was calculated in the frequency domain by solving the full-wave equation. The inverse problem was solved iteratively from low to high discrete frequency components via minimizing a cost function between the modeled and measured data. A quasi-Newton method called the limited-memory Broyden–Fletcher–Goldfarb–Shanno algorithm (L-BFGS) was utilized in the optimization process. Then, bone images were obtained based on the estimation of the velocity and density. The performance of the proposed method was verified by numerical examples, from tubular bone phantom to single distal fibula model, and finally with a distal tibia-fibula pair model. Compared with the high-resolution peripheral quantitative computed tomography (HR-pQCT), the proposed FDFWI can also clearly and accurately presented the wavelength scaled pores and trabeculae in bone images. The results proved that the FDFWI is capable of reconstructing high-resolution ultrasound bone images with sub-millimeter resolution. The parametric bone images may have the potential for the diagnosis of bone disease.</jats:p>

<jats:p>Active control of a fully developed turbulence boundary layer (TBL) over a flat plate has been investigated with a statistical view. The piezoelectric (PZT) oscillator is employed to produce periodic input into the inner region of the TBL. A wall probe is fixed upstream of the oscillator to identify the high- or low-speed fluctuations as the detecting signals. Then, the impact of the detecting signals on the small-scale bursting process is investigated based on the data acquired by the traversing probe downstream of the oscillator. The results indicate that the small-scale bursting intensity is restrained more apparently at high-speed detecting fluctuations but less impacted at low-speed detecting fluctuations. Furthermore, the perturbed-scale fluctuations arrange the small-scale bursting process in the near-wall region. The detecting signals have an obvious impact on this arrangement, especially the high-intensity regions of the small-scale bursting events: the vibration enhances the intensity at high-speed detecting signals but weakens it at low-speed detecting signals in these regions, which gives a direct evidence on how detecting signals interfering the small-scale bursting process.</jats:p>

<jats:p>Nickel phthalocyanine (NiPc) film was deposited onto the surface of flexible conductive glass by rubbing-in technology and used to fabricate devices based on ITO/NiPc/CNT/rubber structure. The <jats:italic>I</jats:italic>–<jats:italic>V</jats:italic> characteristics of the devices were investigated under different uniaxial pressures of 200, 280, and 480 gf/cm<jats:sup>2</jats:sup>, applied perpendicular to the surface of the NiPc film. Results showed that the nonlinearity coefficients of the <jats:italic>I</jats:italic>–<jats:italic>V</jats:italic> curves are in the range of 2 to 3, which was found to be decreased with the increase of the pressure. The rectification ratio of the devices was estimated to be varied from 1.5 to 3 based on the applied pressure. Concluding, the resistance of the active layers was decreased with the increase of both pressure and voltage. We believe that using the rubbing-in technology under sufficient applied pressure it is possible to utilize NiPc for the development of various electronic devices such as diodes, nonlinear resistors, and sensors.</jats:p>

<jats:p>By one-dimensional particle-in-cell (PIC) simulations, the propagation and stability of relativistic electromagnetic (EM) solitary waves as well as modulational instability of plane EM waves are studied in uniform cold electron-ion plasmas. The investigation not only confirms the solitary wave motion characteristics and modulational instability theory, but more importantly, gives the following findings. For a simulation with the plasma density 10<jats:sup>23</jats:sup> m<jats:sup>−3</jats:sup> and the dimensionless vector potential amplitude 0.18, it is found that the EM solitary wave can stably propagate when the carrier wave frequency is smaller than 3.83 times of the plasma frequency. While for the carrier wave frequency larger than that, it can excite a very weak Langmuir oscillation, which is an order of magnitude smaller than the transverse electron momentum and may in turn modulate the EM solitary wave and cause the modulational instability, so that the solitary wave begins to deform after a long enough distance propagation. The stable propagation distance before an obvious observation of instability increases (decreases) with the increase of the carrier wave frequency (vector potential amplitude). The study on the plane EM wave shows that a modulational instability may occur and its wavenumber is approximately equal to the modulational wavenumber by Langmuir oscillation and is independent of the carrier wave frequency and the vector potential amplitude. This reveals the role of the Langmuir oscillation excitation in the inducement of modulational instability and also proves the modulational instability of EM solitary wave.</jats:p>

<jats:p>Based on our previous work (<jats:italic>Phys. Plasmas</jats:italic> <jats:bold>25</jats:bold> 012704 (2018)), a fitting formula is given for electron–ion energy partition fraction of 3.54-MeV fusion alpha particles in deuterium–tritium (DT) plasmas as a function of plasma mass density <jats:italic>ρ</jats:italic>, electron temperature <jats:italic>T</jats:italic> <jats:sub>e</jats:sub>, and ion temperature <jats:italic>T</jats:italic> <jats:sub>i</jats:sub>. The formula can be used in a huge range of the plasma state, where <jats:italic>ρ</jats:italic> varies between 1.0 g/cc ∼ 10.0<jats:sup>3</jats:sup> g/cc and both <jats:italic>T</jats:italic> <jats:sub>e</jats:sub> and <jats:italic>T</jats:italic> <jats:sub>i</jats:sub> change from 0.1 keV to 100.0 keV. Relativistic effect for electrons is investigated including the effect of the projectile recoil in the plasmas at <jats:italic>T</jats:italic> <jats:sub>e</jats:sub> ≥ 50.0 keV. The partition fraction for <jats:italic>T</jats:italic> <jats:sub>e</jats:sub> &gt; <jats:italic>T</jats:italic> <jats:sub>i</jats:sub> is found to be close to that for <jats:italic>T</jats:italic> <jats:sub>e</jats:sub> = <jats:italic>T</jats:italic> <jats:sub>i</jats:sub>. The comparisons with other fitting results are made at some plasma densities when <jats:italic>T</jats:italic> <jats:sub>e</jats:sub> = <jats:italic>T</jats:italic> <jats:sub>i</jats:sub>, and the difference is explained. The fitting result is very close to the calculated one in most cases, which is convenient for the simulation of alpha heating in hot dense DT plasmas for inertial confined fusion.</jats:p>

<jats:p>The structural stabilities and crystal evolution behaviors of the hyper stoichiometric compound ZrC<jats:sub>2</jats:sub> (carbon rich; C/Zr &gt; 1.0) are studied under ambient and high pressure conditions using first-principles calculations in combination with the particle-swarm optimization algorithm. Six viable structures of ZrC<jats:sub>2</jats:sub> in <jats:italic>P</jats:italic>2<jats:sub>1</jats:sub>/<jats:italic>c</jats:italic>, <jats:italic>Cmmm</jats:italic>, <jats:italic>Cmc</jats:italic>2<jats:sub>1</jats:sub>, <jats:italic>P</jats:italic>4<jats:sub>2</jats:sub>/<jats:italic>nmc</jats:italic>, <jats:italic>Immm</jats:italic> and <jats:italic>P</jats:italic>6/<jats:italic>mmm</jats:italic> symmetries are identified. These structures are dynamically stable as their phonon spectra have no imaginary modes at zero pressure or at the selected high-pressure points. Among them, the <jats:italic>P</jats:italic>2<jats:sub>1</jats:sub>/<jats:italic>c</jats:italic> phase represents the ground state structure, whereas <jats:italic>P</jats:italic>2<jats:sub>1</jats:sub>/<jats:italic>c</jats:italic>, <jats:italic>P</jats:italic>4<jats:sub>2</jats:sub>/<jats:italic>nmc</jats:italic>, <jats:italic>Immm</jats:italic> and <jats:italic>P</jats:italic>6/<jats:italic>mmm</jats:italic> phases are part of the phase transition series. The phase order and critical pressures of the phase transition are determined to be approximately 300 GPa according to the equation of states and enthalpy. Furthermore, the mechanical and electronic properties are investigated. The <jats:italic>P</jats:italic>2<jats:sub>1</jats:sub>/<jats:italic>c</jats:italic> and <jats:italic>Cmc</jats:italic>2<jats:sub>1</jats:sub> phases display a semi-metal nature, whereas the <jats:italic>P</jats:italic>4<jats:sub>2</jats:sub>/<jats:italic>nmc</jats:italic>, <jats:italic>Immm</jats:italic>, <jats:italic>P</jats:italic>6/<jats:italic>mmm</jats:italic> and <jats:italic>Cmmm</jats:italic> phases exhibit a metallic nature. Moreover, the present study reveals considerable information regarding the structural, mechanical and electronic properties of ZrC<jats:sub>2</jats:sub>, thereby providing key insights into its material properties and evaluating its behavior in practical applications.</jats:p>

<jats:p>We investigate the thermal stresses for GaAs layers grown on V-groove patterned Si substrates by the finite-element method. The results show that the thermal stress distribution near the interface in a patterned substrate is nonuniform, which is far different from that in a planar substrate. Comparing with the planar substrate, the thermal stress is significantly reduced for the GaAs layer on the patterned substrate. The effects of the width of the V-groove, the thickness, and the width of the SiO<jats:sub>2</jats:sub> mask on the thermal stress are studied. It is found that the SiO<jats:sub>2</jats:sub> mask and V-groove play a crucial role in the stress of the GaAs layer on Si substrate. The results indicate that when the width of V-groove is 50 nm, the width and the thickness of the SiO<jats:sub>2</jats:sub> mask are both 100 nm, the GaAs layer is subjected to the minimum stress. Furthermore, Comparing with the planar substrate, the average stress of the GaAs epitaxial layer in the growth window region of the patterned substrate is reduced by 90%. These findings are useful in the optimal designing of growing high-quality GaAs films on patterned Si substrates.</jats:p>

<jats:p>Resistive switching with a self-rectifying feature is one of the most effective solutions to overcome the crosstalk issue in a crossbar array. In this paper, a memory device based on Pt/TiO<jats:sub> <jats:italic>x</jats:italic> </jats:sub>/W structure with self-rectifying property is demonstrated for write-once-read-many-times (WORM) memory application. After programming, the devices exhibit excellent uniformity and keep in the low resistance state (LRS) permanently with a rectification ratio as high as 10<jats:sup>4</jats:sup> at ± 1 V. The self-rectifying resistive switching behavior can be attributed to the Ohmic contact at TiO<jats:sub> <jats:italic>x</jats:italic> </jats:sub>/W interface and the Schottky contact at Pt/TiO<jats:sub> <jats:italic>x</jats:italic> </jats:sub> interface. The results in this paper demonstrate the potential application of TiO<jats:sub> <jats:italic>x</jats:italic> </jats:sub>-based WORM memory device in crossbar arrays.</jats:p>

<jats:p>Nanowires have recently attracted more attention because of their low-dimensional structure, tunable optical and electrical properties for next-generation nanoscale optoelectronic devices. CdS nanowire array, which is (002)-orientation growth and approximately perpendicular to Cd foil substrate, has been fabricated by the solvothermal method. In the temperature-dependent photoluminescence, from short wavelength to long wavelength, four peaks can be ascribed to the emissions from the bandgap, the transition from the holes being bound to the donors or the electrons being bound to the acceptors, the transition from Cd interstitials to Cd vacancies, and the transition from S vacancies to the valence band, respectively. In the photoluminescence of 10 K, the emission originated from the bandgap appears in the form of multiple peaks. Two stronger peaks and five weaker peaks can be observed. The energy differences of the adjacent peaks are close to 38 meV, which is ascribed to the LO phonon energy of CdS. For the multiple peaks of bandgap emission, from low energy to high energy, the first, second, and third peaks are contributed to the third-order, second-order, and first-order phonon replica of the free exciton A, respectively; the fourth peak is originated from the free exciton A; the fifth peak is contributed to the first-order phonon replica of the excitons bound to neutral donors; the sixth and seventh peaks are originated from the excitons bound to neutral donors and the light polarization parallel to the <jats:italic>c</jats:italic> axis of hexagonal CdS, respectively.</jats:p>