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Moving loads will have a certain impact on the safety of the structures. Since concrete is a viscoelastic material, the elastic concrete model cannot describe its viscoelastic characteristics under moving loads. It is necessary to establish a model that can describe the viscoelastic characteristics of concrete materials. In addition, the layered of the soil is also an important factor affecting the propagation of subway vibration waves. Considering the effects of the properties of the concrete material of the subway tunnel structure and the layered soil foundation as well as the load velocity on the vibration of the ground surface caused by the moving load, the standard linear elastic solid Euler beam model is described for the subway tunnel structure in this paper. The equivalent stiffness of the layered soil-viscoelastic beam coupling system subjected to a moving load is formed by using the transmission and reflection matrix (TRM) method. The numerical solution of ground surface displacement caused by subway tunnel in time-space domain is obtained by IFFT algorithm. The correctness of the algorithm is verified by comparing with the reference results. Numerical results show that, with the increase of the viscous coefficient of the viscoelastic Euler beam, the vibration amplitude of the ground surface will decrease. Up to a certain value of the increasing the viscous coefficient of the Euler beam, it will have little effect on the vibration amplitude of the ground surface. Therefore, the standard solid model of viscoelastic Euler beam can well describe the creep and relaxation of materials. The model of viscoelastic beam is reasonable for the working condition of subway tunnel concrete structure. At high speed of moving load, the maximum value of ground surface displacement spectrum will appear at the smaller frequency domain and the maximum value of displacement spectrum will also increase for the soft layer soil, while it is opposite to that of the stiffer layer soil.

A cheap and compact Nd:YVO4 laser at 1087.5 nm pumped by an edge-emitting laser diode (LD) array is demonstrated. By specially restraining the other lines at 1064.1, 914.0, and 1342.0 nm with a refined output mirror having low-reflectivity at 1064.1 nm (R1064.1 = 3%) and high-reflectivity (R1087.5 = 92%) at 1087.5 nm, a low-gain line at 1087.5 nm is achieved. The output power is 8.79 W at the 807.9 nm pump power of 37.43 W with an optical-optical conversion efficiency of 23.5%.

In this study, aluminum-doped zinc oxide (Al:ZnO) thin films were grown by high-speed atmospheric atomic layer deposition (AALD), and the effects of air annealing on film properties are investigated. The experimental results show that the thermal annealing can significantly reduce the amount of oxygen vacancies defects as evidenced by X-ray photoelectron spectroscopy spectra due to the in-diffusion of oxygen from air to the films. As shown by X-ray diffraction, the annealing repairs the crystalline structure and releases the stress. The absorption coefficient of the films increases with the annealing temperature due to the increased density. The annealing temperature reaching 600 &deg, C leads to relatively significant changes in grain size and band gap. From the results of band gap and Hall-effect measurements, the annealing temperature lower than 600 &deg, C reduces the oxygen vacancies defects acting as shallow donors, while it is suspected that the annealing temperature higher than 600 &deg, C can further remove the oxygen defects introduced mid-gap states.

Aluminum-doped ZnO (AZO) films are prepared by using spatial atomic layer deposition (ALD). The precursors of trimethylaluminum (TMA) and diethylzinc (DEZ) are concurrently introduced into the deposition region. The amount ratio of TMA to DEZ vapor molecules is controlled by varying the temperature of the precursor bubblers from 5° to 77 °C. It is found that the Al doping level can be predicted using the amount ratio of TMA to DEZ output vapors. The film prepared at the bubbler temperature of 41 °C exhibits an Al content of ~1% and a low resistivity of 3.5 × 10−4 Ω-cm comparable to indium tin oxide films. Furthermore, the Al-doping efficiency is as high as 73%. This study is useful in applying the ALD technique to films with multicomponent oxides.

Graphene-oxide (GO) as saturable absorber (SA) for a 1342 nm passively Q-switched Nd:YVO 4 laser is reported. This system produces laser pulse as narrow as 329 ns with a repetition rate of 214 kHz and the largest output power of 520 mW. Our results demonstrate that GO can be used as an excellent and efficient SA for Nd 3+ -doped lasers at 1.3 μm.

We report a compact continuous-wave (CW) eye-safe Nd:YVO4/PPMgLN intra-cavity optical parametric oscillator (IOPO) based on a shared resonator, in that the fundamental laser and signal light share a same single resonator. At a pump power of 10 W, this OPO system produces an output power at 1476.4 nm of 580 mW. Depending on the 3 grating periods of the PPMgLN crystal (28.5, 29.0 and 29.5 μm), we could enable 3 signal wavelengths at 1429.8, 1450.9 and 1476.4 nm, respectively.

Zinc oxide (ZnO) attracts much attention owing to its remarkable electrical and optical properties for applications in optoelectronics. In this study, ZnO thin films were prepared by spatial atomic layer deposition with diethylzinc and water as precursors. The substrate temperature was varied from 55 to 135 &deg, C to investigate the effects on the optical, electrical, and structural properties of the films. All ZnO samples exhibit an average transmittance in visible and near-infrared light range exceeding 80% and a resistivity in the range of (3.2&minus, 9.0) &times, 10&minus, 3 &Omega, &middot, cm when deposited on a borosilicate glass with a refractive index of &asymp, 1.52. The transmittance, band gap, refractive index, and extinction coefficient are rarely affected, while the resistivity only slightly decreases with increasing temperature. This technique provides a wide process window for depositing ZnO thin films. The results revealed that the films deposited at a substrate of 55 &deg, C were highly crystalline with a preferential (1 0 0) orientation. In addition, the grains grow larger as the substrate temperature increases. The electrical properties and reliability of ZnO/PET samples are also studied in this paper.