变频谐振融冰的探讨

电力导线的交流阻抗比直流阻抗大,故交流融冰比直流融冰的融冰距离短。交流融冰受交流阻抗影响,应用范围较窄。导线的交流阻抗主要是感抗,若融冰回路中引入容抗以降低线路总阻抗,可延长融冰距离。当回路中的感抗与容抗相等,回路阻抗呈纯阻性,这一状况称为谐振。利用谐振时阻抗最小、电流最大的特点,对变频谐振融冰进行探讨。

A Review of Wideband Circularly Polarized Dielectric Resonator Antennas

This article presents a technical review of circularly polarized(CP) dielectric resonator antennas(DRA) for wideband applications.The primary objective of this review is,to highlight the techniques used by different researchers for generating circular polarization in DRA.First,a general idea of circular polarization and it advantages over linear polarization is presented,and then all the major developments made in the CP DRA are highlighted.The emphasis of the paper is on the wideband circularly polarized dielectric resonator antenna.The current state of the art and all the realizable features of the CP DRA are addressed comprehensively.Finally,some recommendations for future CP DRAs are given and the paper ends with concluding remarks.

Silicon carbide resonant tuning fork for microsensing applications in high-temperature and high G-shock environments

We present the fabrication and testing of a silicon carbide （SiC） balanced mass doublended tuning fork that survives harsh environments without compromising the device strain sensitivity and resolution bandwidth. The device features a material stack that survives corrosive environments and enables high-temperature operation. To perform hightemperature testing, a specialized setup was constructed that allows the tuning fork to be characterized using traditional silicon electronics. The tuning fork has been operated at 600°C in the presence of dry steam for short durations. This tuning fork has also been tested to 64 000 G using a hard-launch, soft-catch shock implemented with a light gas gun. However, the device still has a strain sensitivity of 66 Hz/μe and strain resolution of 0. 045 μe in a 10 kHz bandwidth. As such, this balanced-mass double-ended tuning fork can be used to create a variety of different sensors including strain gauges, accelerometers, gyroscopes, and pressure transducers. Given the adaptable fabrication process flow, this device could be useful to micro-electro-mechanical systems （MEMS） designers creating sensors for a variety of different applications.

Controlled Phase Flip Gate and Its Application in Low-Q Cavities by Single-Photon Input-Output Process

By employing an auxiliary cavity, we investigate the possibility to implement the conditional phase flip （CPF） gate on two atoms confined in separate 1ow-Q cavities by single-photon input-output process, based on the Faraday rotation. This indicates a universal quantum computing available with sophisticated cavity QED techniques. As examples, we carry out generation of duster states of distant atomic qubits and accomplish a teleportation based on Bell-state measurement in low-Q cavities.

Wide and Fast Wavelength-Swept Fiber Lasers Based on Dispersion Tuning and Their Application to Optical Coherence Tomography

We recently proposed a new class of wavelength-swept lasers for swept-source optical coherence tomography （SS-OCT）. It uses the same gain medium with the conventional swept lasers, but does not require any tunable filters. It is based on a principle called ＂dispersion tuning＂, in which a highly dispersive medium is inserted in the laser cavity, and loss/gain modulation is applied to mode-lock the laser. Since the cavity contains no mechanical components, such as tunable filters, we could achieve the very high sweep rate. In this review paper, we describe the principle of the dispersion-tuned swept lasers in detail and present our recent work on the application to the SS-OCT system.