As the internal combustion engine moves into the 21st century, fully flexible valve actuation systems are being proposed as an enabling technology for advanced internal combustion engine concepts. Electro-hydraulic valve actuator systems are being considered as a potential variable valve technology. Compared to the servo control system, the system using a proportional valve has the advantages of low price, high anti-pollution ability and high reliability. Our research focuses on exploring the dynamic characteristic of the electro-hydraulic variable valve system, which is based on three-way proportional reducing valve. In this paper, the structure and working principles of the system are described. The dynamic mathematical model of the system is derived. From the analysis of a linearized model and dynamic simulation, it is demonstrated that the system will be stable only if the proportional reducing valve has a positive opening. Some structural factors that affect the system's dynamic characteristics, such as input signal, the stiffness of the return spring and the pre-tightening force of the return spring, are studied using AMESim. The experimental results coincide with the theoretical and simulated analyses. Further study shows that the dynamic response can be improved effectively by adopting closed-loop control of valve lift.

In this article, a new kind of linear actuator for the deep-sea sampling valve has been described. Based on the working principle of the triggering ring, the actuator employs a preloaded spring to generate an output force and linear movement. The actuator is designed to be used 4000 m underwater and can produce a force of 510 N at the maximal output displacement of 3.5 mm, which can be easily modified by changing the preloaded spring and spring seats. The actuator has been successfully tested to actuate the sampling valve at an ambient pressure of 40 MPa.

The metallurgical characteristics and properties of bearing steel processed by ladle refining with vacuum argon deoxidation (VAD), with nonvacuum argon stirring (AS), and with electroslag remelting (ESR) are reported in this paper. Based on analysis, determination of nonmetallic inclusions in steel, and fatigue life test of steel products, the main results obtained are as follows: (1) due to low oxygen content, fine dispersion, improved characteristic and morphology of inclusions, and elimination of D-type inclusions in steel, the fatigue life of electric furnace (EF) + VAD or AS steel is twice as high as that of EF steel; (2) although the amount of inclusion and oxygen in ESR steel is higher than that of ladle-refined steel, the fatigue life of ESR steel is higher than the latter because of its fine and well dispersed inclusion.

Reconfigurable multichannel optical filters (MOFs) with a high resolution are key devices for high-spectral-efficiency multi-carrier optical transmission systems. However, very few on-chip MOFs reported so far can meet the demands of high spectral resolution, device complexity, and scalable input/output ports. Here, we present a 10 GHz-bandwidth self-configurable silicon MOF using a resonator-assisted discrete-Fourier-transform interferometer. With the help of ultra-low-loss silicon photonic waveguides and low-phase-error Mach–Zehnder switches, the present chip features a low excess loss, low power consumption, high port-count scalability, and sub-GHz spectral resolution. In particular, the present MOF is capable of performing some specific filtering responses with, e.g., near-rectangular or sinc shapes. Furthermore, an efficient self-configuring approach is also developed for the present chip to be programmable, so that different spectral responses can be achieved as desired by automatically optimizing the settings of all the tuning elements, showing great potential for high-capacity optical communication networks.