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A coherent multi-wavelength Brillouin random fiber laser with randomly distributed Rayleigh scattering feedback was demonstrated. Up to six orders Stokes random lasing radiations were generated with an unprecedented high optical signal-to-noise ratio of ∼47dB.
Energy storage technology is an important measure for power output of new energy generation system. T-type three-level structure is adopt as the topology of energy storage inverter. Mathematical model of grid-connected operation in ABC coordinate system and dq coordinate system is built. A double closed loop control strategy of which inner loop current and outer loop power control is proposed. The...
Bulk data transfer is facing significant challenges in the coming era of big data. There are multiple performance bottlenecks along the end-to-end path from the source to destination storage system. The limitations of current generation data transfer tools themselves can have a significant impact on end-to-end data transfer rates. In this paper, we identify the issues that lead to underperformance...
The stripe laser based stereo vision is often used in robot vision-guided system in the eye-in-hand configuration. The 3D scene is reconstructed from many 3D stripes obtained in stripe laser based stereo vision. But 3D objects can not be recognized by 3D stripe information. In 3D cluttered scene, the recognition of 3D objects is also difficult due to the object pose and match. In fact, the video from...
Passive acoustic recording has great potential for monitoring soniferous endangered and cryptic species. However, this approach requires analysis of long duration environmental acoustic recordings that span months or years. There is a variety of approaches to analysing acoustic data. However, it is unclear which approaches are best suited for monitoring of endangered species in the wild. Specifically,...
In this paper, a surrounding control problem for second-order agent system is investigated. A set of followers composed by the second-order agent networks is applied to surround a team of static leaders into a convex hull spanned by these followers. The problem is considered under a decentralized estimation-and-control framework by using tools from algebraic graph theory and Lyapunov stable theory...
This paper presents the design of a TE10-to-TE61 mode coupler for a 372 GHz gyrotron travelling wave amplifier. The optimized coupler was able to achieve an −1 dB transmission over the frequency band of 360–384 GHz. The transmission decreases by 1.2 dB when the copper conductivity of 0.5E7 S/m was used in the simulation. The designed coupler was scaled to W-band for manufacture and measurement. The...
Broadband microwave windows for applications in both millimeter wave and terahertz wave vacuum electron devices were designed, simulated and a W-band multilayer window constructed and measured. These windows are based on the multilayer configuration and offer broadband transmission with a very low reflection. Operating over a wide frequency bandwidth of 10% and 5% in their respective frequency bands...
This paper presents the design, simulation and measurement of two mode converting corrugated horns for application as the output launcher for a gyro-amplifier. Operating over the 90 to 100 GHz frequency range the horns act to convert the TE11 mode to the Gaussian-like HE11 mode. The difference in the horns is one was made initially to meet a more moderate Gaussian content specification while the other...
A W-band quasi-optical horn with smoothly profiled circular inner surface was optimized and measured for a gyrotron traveling wave amplifier. It was designed to achieve low reflection, high fundamental Gaussian mode content and high directivity in the desired frequency range of 90 to 100 GHz. In the measurement, the reflection of the TE11 mode was lower than −37 dB and the directivity was ∼27 dB with...
Design and experimental results of a broadband, high power, millimetre-wave gyrotron traveling wave amplifier (gyro-TWA) operating in the 75–110 GHz frequency band and based on a helically corrugated interaction region (HCIR) and cusp electron beam source are presented. The second harmonic cyclotron mode of the electron beam was used to match the dispersion of an eigenwave in the HCIR, achieving energy...
This paper proposes to generate a smart tool that can inherently and effectively capture the results of parameter variations on the system responses of lumped and distributed electrical circuits. This methodology leverages the so-called affine arithmetic and represents parameter-dependent responses in terms of a multivariate polynomial. The affine representation is propagated from input parameters...
Input couplers for mm-wave gyrotron traveling wave amplifiers (gyro-TWAs) were designed. A W-band input coupler composed of a T-junction and a broadband reflector was constructed and measured in W-band. It achieved a transmission coefficient of −2.2 dB including the pillbox window and a waveguide bend. A multiple-hole coupler was designed and simulated at 372 GHz. Without considering the Ohmic loss,...
Tunable frequency selective surfaces (FSSes) usually have better flexibility and are employed by many applications. However, the frequency tunable range is usually not very broad especially for the band-stop ones. At the same time, a tunable FSS usually requires a bias network, which makes the design even more difficult. In this paper, a broadband tunable band-stop AFSS is presented. The tunable ability...
In this paper, the zirconia toughened alumina (ZTA) ceramics with different content of zirconia were fabricated. The dielectric relaxation properties were investigated by using thermally stimulated depolarization current (TSDC) method. The observed TSDC peaks were attributed to defect dipole polarization, and the related activation energies were evaluated by a fitting method. The influence of zirconia...
Model predictive control is a kind of control method based on parameter model. However, in the actual system, the parameters of the motor may deviate from the parameters in the model due to the influence of various objective factors, leading to deterioration of the control performance. In this paper, a strong parameters robustness model predictive current control (MPCC) method for permanent-magnet...
A helical long-period grating (HLPG) was written in a polarization maintaining fiber (PMF) with CO2 laser. The twist characteristics of individual and cascaded PMF-HLPG were investigated experimentally. It was found that PMF-HLPG behaved differently with a different light input. When a polarized light was launched into the cascaded PMF-HLPGs with opposite helical direction, a high twist sensitivity...
For metro applications, direct detection offers the advantages of low cost and low complexity. Discrete multi-tone (DMT) is a promising format due to its high spectral efficiency, flexibility and tolerance to chromatic dispersion (CD). In this work, single-side-band-DMT (SSB-DMT) and tuneable electrical dispersion compensation double side-band-DMT (TEDC-DSB-DMT) are summarized and compared.
Radio fuze has attracted much study in ground-based air-defence artillery field. It requires a high-resolution radar to recognize, position, track and control multiple projectiles. For this, we present a cooperative multiple-target tracking (CMTT) mechanism with MIMO radar, where projectiles can actively transmit signal to radar for target identification, localization, and tracking. The signal is...
Next Generation Passive Optical Network Stage 2 (NG-PON2) features multiple wavelength channels. Channel bonding combines multiple NG-PON2 wavelength connections in parallel to increase the access network throughput beyond the capacity of a single connection. It enhances the access network peak rate provisioning. Channel bonding is actively studied in the ITU Telecommunication Standardization Sector...
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