Qin Shiqiao

Broadband single-layered graphene absorber using periodic arrays of graphene ribbons with gradient width

We demonstrate that a broadband single-layered graphene absorber can be obtained in the THz range using periodic arrays of chemically doped graphene ribbons with gradient width, supported on a dielectric film placed on a thick piece of metal. The working bandwidth of 90% absorption for this structure is as high as 1.3 THz with a central frequency of 3 THz. The broadband operation mechanism is a result of the varying continuous plasmon resonances occurring in graphene ribbons with gradient width. The operation wavelength can be expanded to the far-infrared range.

Tunable terahertz plasmon in grating-gate coupled graphene with a resonant cavity

Plasmon modes in graphene can be tuned into resonance with an incident terahertz electromagnetic wave in the range of 1–4 THz by setting a proper gate voltage. By using the finite-difference-time-domain (FDTD) method, we simulate a graphene plasmon device comprising a single-layer graphene, a metallic grating, and a terahertz cavity. The simulations suggest that the terahertz electric field can be enhanced by several times due to the grating–cavity configuration. Due to this near-field enhancement, the maximal absorption of the incident terahertz wave reaches up to about 45%.

Annealing effect of platinum-incorporated nanowires created by focused ion/electron-beam-induced deposition

Focused ion-beam-induced deposition (FIBID) and focused electron-beam-induced deposition (FEBID) are convenient and useful in nanodevice fabrication. Since the deposition is from the organometallic platinum precursor, the conductive lines directly written by focused ion-beam (FIB) and focused electron-beam (FEB) are carbon-rich materials. We discuss an alternative approach to enhancing the platinum content and improving the conductivity of the conductive leads produced by FIBID and FEBID, namely an annealing treatment. Annealing in pure oxygen at 500 °C for 30 min enhances the platinum content values from ~18% to 30% and ~ 50% to 90% of FIBID and FEBID, respectively. Moreover, we find that thin films will be formed in the FIBID and FEBID processes. The annealing treatment is helpful to avoid the current leakage caused by these thin films. A single electron transistor is fabricated by FEBID and the current—voltage curve shows the Coulomb blockade effect.

A Transmission-Type Electrically Tunable Polarizer Based on Graphene Ribbons at Terahertz Wave Band

We theoretically and numerically demonstrate that a transmission-type electrically tunable polarizer can be realized by using graphene ribbons supported on a dielectric film with a graphene sheet behind. The polarization mechanism originates from the antenna plasmon resonance of graphene stripes. The results of full-wave numerical simulations reveal that transmittance of 0.70 for one polarization and 0.0073 for another polarization can be obtained at normal incidence. The transmission-type electrically tunable polarizer provides and facilitates a variety of applications, including filtering, detecting, and imaging.

Prediction of ship pitch motion by dual autoregressive model

We focus on the pitch motion prediction for the ship heading maneuver operation. A dual Autoregressive (AR) model is proposed to sensitively predict the ship pitch motion time series data, comparing to the tradition AR model, which is incapable of predicting the static component of the ship pitch motion time series data. Potential application of this work is establishing a superior real-time ship motion predict system.

A hybrid AR-DWT-EMD model for the short-term prediction of nonlinear and non-stationary ship motion

Reliable and accurate short-term prediction of ship motions improves the safety in ship motion related maritime operations, where the empirical mode decomposition (EMD) is widely used for its advantages like the satisfactory nonlinear and non-stationary processing capability. Therefore a hybrid autoregressive AR-DWT-EMD model is proposed for the short-term prediction of non-stationary and nonlinear ship motion. The proposed hybrid model is the combination of AR-EMD model and the discrete wavelet decomposition (DWT). Compared with the traditional AR model, hybrid AR-DWT model, and hybrid AR-EMD model, the hybrid AR-DWT-EMD model is more capable to handle the nonlinear and non-stationary signals. The prediction results suggest that better predictions are obtained by the proposed AR-DWT-EMD model than other models.