Design, simulation and experiment of a cusp electron beam for millimeter wave gyro-devices

The design, simulation and experiment of a thermionic cusp electron gun that is to be used for millimeter wave generation will be presented. A cusp gun uses a non-adiabatic magnetic field reversal to obtain azimuthal motion on an electron beam resulting in an annular shaped, axis-encircling beam. The cusp gun was designed to generate a beam of 1.5A at 40kV with an adjustable velocity ratio of up to 3.0. The beam had a simulated axial velocity spread of 7.4% and alpha spread of 10.1%. The beam had an averaged radius of 0.35mm and beam thickness of 0.05mm which is ideal to drive sub-mm wave gyro-devices under investigation

Multi-mode coupling wave theory for helically corrugated waveguide

Helically corrugated waveguide has been used in various applications such as gyro-backward wave oscillators, gyro-traveling wave amplifier and microwave pulse compressor. A fast prediction of the dispersion characteristic of the operating eigenwave is very important when designing a helically corrugated waveguide. In this paper, multi-mode coupling wave equations were developed based on the perturbation method. This method was then used to analyze a five-fold helically corrugated waveguide used for X-band microwave compression. The calculated result from this analysis was found to be in excellent agreement with the results from numerical simulation using CST Microwave Studio and vector network analyzer measurements

Optimization of a triode-type cusp electron gun for a W-band gyro-TWA

A triode-type cusp electron gun was optimized through numerical simulations for a W-band gyrotron traveling wave amplifier. An additional electrode in front of the cathode could switch the electron beam on and off instantly when its electric potential is properly biased. An optimal electron beam of current 1.7 A and velocity ratio (alpha) of 1.12 with an alpha spread of ~10.7% was achieved when the triode gun was operated at 40 kV

Indoor pedestrian dead reckoning calibration by visual tracking and map information

Currently, Pedestrian Dead Reckoning (PDR) systems are becoming more attractive in market of indoor positioning. This is mainly due to the development of cheap and light Micro Electro-Mechanical Systems (MEMS) on smartphones and less requirement of additional infrastructures in indoor areas. However, it still faces the problem of drift accumulation and needs the support from external positioning systems. Vision-aided inertial navigation, as one possible solution to that problem, has become very popular in indoor localization with satisfied performance than individual PDR system. In the literature however, previous studies use fixed platform and the visual tracking uses feature-extraction-based methods. This paper instead contributes a distributed implementation of positioning system and uses deep learning for visual tracking. Meanwhile, as both inertial navigation and optical system can only provide relative positioning information, this paper contributes a method to integrate digital map with real geographical coordinates to supply absolute location. This hybrid system has been tested on two common operation systems of smartphones as iOS and Android, based on corresponded data collection apps respectively, in order to test the robustness of method. It also uses two different ways for calibration, by time synchronization of positions and heading calibration based on time steps. According to the results, localization information collected from both operation systems has been significantly improved after integrating with visual tracking data

Bandwidth study of the microwave reflectors with rectangular corrugations

The mode-selective microwave reflector with periodic rectangular corrugations in the inner surface of a circular metallic waveguide is studied in this paper. The relations between the bandwidth and reflection coefficient for different numbers of corrugation sections were studied through a global optimization method. Two types of reflectors were investigated. One does not consider the phase response and the other does. Both types of broadband reflectors operating at W-band were machined and measured to verify the numerical simulations

Development and Evaluation of Feline Tailored Amlodipine Besylate Mini-Tablets Using l-lysine as a Candidate Flavouring Agent

Felines may find orally administered medicines unpalatable, thus presenting a problem in the treatment of chronic conditions such as hypertension, a commonly diagnosed condition in felines requiring daily administration of medication. A pertinent example is amlodipine besylate, formulations of which are known to be poorly tolerated by cats. There is therefore a need to develop feline-specific delivery approaches that are both simple to administer and mask the taste of the drug, thereby enhancing the owner's commitment to treatment and the associated therapeutic outcome for the companion animal. In addition, it is helpful to develop accessible and reproducible means of assessing taste for pre-clinical selection, hence the use of recently developed taste biosensor systems for veterinary applications is an area of interest. This study focuses on developing feline-specific amlodipine besylate formulations by improving the taste using a suitable flavouring agent while reducing dosage form size to a 2 mm diameter mini-tablet. The choice of L-lysine as a flavouring agent was based on the dietary and taste preference of cats. The impact of L-lysine on the taste perception of the formulation was evaluated using a biosensor system (E-tongue) fitted with sensors sensitive to bitter tastes. The results showed L-lysine successfully masked bitterness, while the drug release studies suggest that it has no impact on drug dissolution. In addition, tableting parameters such as tablet mass uniformity, content uniformity, tablet diameter, thickness and hardness were all satisfactory. The present study suggests that amlodipine besylate mini-tablets containing L-lysine could improve the palatability and in turn support product acceptability and ease of administration. These data could have an impact on orally administered medicines for cats and other veterinary species through product differentiation and competitive advantage in the companion animal market sector. The study also outlines the use of the electronic tongue as a tool for formulation selection in the veterinary field

The Electrically Evoked Compound Action Potential: From Laboratory to Clinic

The electrically evoked compound action potential (eCAP) represents the synchronous firing of a population of electrically stimulated auditory nerve fibers. It can be directly recorded on a surgically exposed nerve trunk in animals or from an intra-cochlear electrode of a cochlear implant. In the past two decades, the eCAP has been widely recorded in both animals and clinical patient populations using different testing paradigms. This paper provides an overview of recording methodologies and response characteristics of the eCAP, as well as its potential applications in research and clinical situations. Relevant studies are reviewed and implications for clinicians are discussed

Wide-band HE11 mode terahertz wave windows for gyro-amplifiers

Broadband HE11 mode output windows, based on the multilayer concept, are studied for high power gyro-amplifiers operating in the low terahertz region. As the wave power in the hybrid HE11 mode is concentrated in the center of the circular waveguide, smaller reflection and better coupling to the fundamental free space Gaussian mode can be achieved for the windows. Two windows are designed for optimized performance through simulations for operation in two frequency ranges of 360– 400 GHz and 90–100 GHz. The simulated performance, practical constraints in realization and manufacturing methods of the 90–100 GHz window is discussed. This window was constructed and microwave properties measured showing a lower than -27 dB reflection. This result agrees with simulation data which validates the simulation methodology and effectiveness of the design

Measurement of a W-band output launcher system for a broadband gyro-TWA

An output system for a W-band (90-100 GHz) gyrotron-traveling wave amplifier is designed, simulated, measured and the results are presented. This is an updated system based on a previous design and the output shows more favorable properties for the amplifiers intended application, as a millimetre wave source in a cloud sensing radar. A greater than -30 dB reflection was measured over the frequency range and high Gaussian content obtained