Wideband dispersion removal and mode separation of Lamb waves based on two-component laser interferometer measurement

Ultrasonic Lamb waves are considered as a sensitive and effective tool for nondestructive testing and evaluation of plate-like or pipe-like structures. The nature of multimode and dispersion causes the wave packets to spread, and the modes overlap in both time and frequency domains as they propagate through the structures. By using a two-component laser interferometer technique, in combination with a priori knowledge of the dispersion characteristics and wave structure information of Lamb wave modes, a two-component signal processing technique is presented for implementing dispersion removal and mode separation simultaneously for two modes mixture signals of Lamb waves. The proposed algorithm is first processed and verified using synthetic Lamb wave signals. Then, the two-component displacements test experiment is conducted using different aluminum plate samples. Moreover, we confirm the effectiveness and robustness of this method.

High-speed polarization mode dispersion compensation in a 43-Gb/s RZ-DQPSK transmission system over 1200 km of standard single-mode fibre

This paper reports that the designed optical polarization mode dispersion compensator shows a good performance under the real-time variation of differential group delay, state of polarization and principal state of polarization in a （40×43）-Gb/s dense-wavelength-multiplexing, 1200-km enhanced return-to-zero differential-quadrature-phase-shift- keying （RZ-DQPSK） system. The polarization mode dispersion tolerance of the system is improved by 26 ps using the optical polarization mode dispersion compensator. The short and long time stabilities are tested with the bit error ratio recorded.

A Comparative Study of two Different Types of Enterprise Salary Mode

Human resource is the core of organizational development resources, the organization＇s competition more embodied in the talent competition. Pay as one of the important means of incentive talents, plays an important role in talent organization plan. Compensation management has become the core content of enterprise human resources management, compensation mode is about employee compensation management to study and the trend of the style, it provides reference for compensation managers implement compensation management activity basic paradigm or frame type style. Different modes of compensation, conveys the organization of different development direction, in determining job satisfaction, stimulate staff＇s work motivation, plays an important role in the enhancement enterprise cohesion, etc. This article through to the state-owned enterprise and private enterprise specific comparison on the differences of two compensation modes, to explore the adaptability of different mode of enterprise, for other enterprises to provide reference for reasonable and effective compensation system.

Influence of Different Compensation Modes on Morphological and Electrical Characteristics of Secondary Arcs

UHV transmission lines are usually equipped with high-voltage shunt reactors.These reactors and the resulting degree of compensation affect the voltage,current,and other electrical characteristics of secondary arcs.In this paper,a low-voltage experimental simulation setup to produce secondary arcs in different compensation modes is established,and the morphological and electrical characteristics of recorded arc images and discharge waveforms are analyzed.For morphological characteristics,the degree of secondary arcs is compared for different compensation modes.For electrical characteristics,the arc waveform,volt–current characteristics,and zero-current time of secondary arcs are compared for different compensation modes.These results provide a foundation to determine the time of extinction of secondary arcs on overhead lines in the case of compensation,as well as technical support to develop effective arc suppression and extinction techniques.

Pressure-tracking control of a novel electro-hydraulic braking system considering friction compensation

This work presents an integrated pressure-tracking controller for a novel electro-hydraulic brake(EHB) system considering friction and hydraulic disturbances. To this end, a mathematical model of an EHB system, consisting of actuator and hydraulic sub-systems, is derived for describing the fundamental dynamics of the system and designing the controller. Due to sensor inaccuracy and measurement noise, a Kalman filter is constructed to estimate push rod stroke for generating desired master cylinder pressure. To improve pressure-tracking accuracy, a linear friction model is generated by linearizing the nonlinear Tustin friction model, and the unmodeled friction disturbances are assumed unknown but bounded. A sliding mode controller is designed for compensating friction disturbances, and the stability of the controller is investigated using the Lyapunov method. The performance of the proposed integrated controller is evaluated with a hardware-in-the-loop(HIL) test platform equipped with the EHB prototype. The test results demonstrate that the EHB system with the proposed integrated controller not only achieves good pressure-tracking performance, but also maintains robustness to friction disturbances.

A novel tunable polarization mode dispersion compensator with strain chirped fiber Bragg gratings

A tunable polarization mode dispersion (PMD) compensator based on strain-ckirped fiber Bragg gratings (FBGs) is proposed. It natures in flexible designing, large tuning range, without using linear or nonlinear chirped phase mask, fast tuning response time, continuously adjustable, all-fiber based, compact, and cheap.

Digital 1 V 82 μW Pseudo-Two-Stage Class-AB OTA

A low power digital operational transconductance amplifier （OTA） was developed for low voltage switched capacitor applications. The OTA has a high slew rate （SR） and a large open loop gain with a dif- ferential pseudo-two-stage Class-AB structure. A fully compensated depletion mode capacitor is used in the switched capacitor common mode feedback block instead of a metal-insulator-metal （MIM） capacitor to reduce the fabrication cost. Simulations show that with a 1.0-V supply voltage and a 34-pF load at each output terminal, this digital differential pseudo-two-stage Class-AB OTA realized in 0.13-μm technology achieves a 63.5-dB DC gain and a 0.83-V output swing. The slew rate is ±16.29V/μs and the total power dissipation is only 82 μW.