Search

Scraper conveyor is an important equipment for excavating and transporting materials in fully mechanized mining face. With the continuous development of computer technology and fluid mechanics, the research of hydraulic coupling has gone deep into all levels, not only limited to the structural characteristics of the hydraulic coupling itself, three-dimensional liquid electromagnetic calculation, three-dimensional design methods, but also involved in the optimization of the characteristic parameters of the hydraulic coupling. This topic is the technical design of the electromagnetic control valve of the hydraulic coupling, including the structural design of the main valve, the structural design of the pilot valve, and the three-dimensional modeling of the main valve. The research on the solenoid valve technology of hydraulic coupling conforms to the development concept and trend and has broad prospects

This paper deals with the event triggered filtering problem for a class of delayed discrete-time Markov jump neural networks, where a resilient filter with parameter uncertainties is adopted. The aim of this paper is to design a suitable filter which ensures that the filtering error system is stochastically stable and satisfies a prescribed mixed passivity and H∞ performance. Sufficient conditions for solvability of such a problem are developed. Based on the obtained conditions, an explicit expression of the desired resilient filter is proposed. Finally, an example is presented to show the usefulness of the proposed scheme.

The emission of dispersive wave and soliton linear-wave interaction are two of the widely studied nonlinear phenomena in fiber optics. They manifest as the generation of a new spectral component when a strong ultrashort optical pulse with/without a weak linear-wave propagates along an optical fiber in the presence of higher-order dispersions. Recent works have demonstrated that the dispersive wave generation and soliton linear-wave interaction can be interpreted in the spectral domain through the cascade of four-wave mixing processes. We show in this work that the emission of the dispersive wave is a special case of soliton linear-wave interactions, in which the linear-wave is degenerate from the soliton field. By studying the driving field (soliton) and linear-wave in different modes, the role of the soliton is to provide cross-phase modulation to the linear-wave as in the earlier studies, while the fiber dispersion is to detrimentally shape the pure cross-phase modulated linear-wave spectra into the seemingly ’idler component’. We present a theoretical model to approximately calculate the spectral profile of the generated idler/dispersive wave and further verify our model with numerical simulations.

The k-nearest neighbor (kNN) method only uses samples’ paired distance to perform fault detection. It can overcome the nonlinearity, multimodality, and non-Gaussianity of process data. However, the nearest neighbors found by kNN on a data set containing a lot of outliers or noises may not be actual or trustworthy neighbors but a kind of pseudo neighbor, which will degrade process monitoring performance. This paper presents a new fault detection scheme using the mutual k-nearest neighbor (MkNN) method to solve this problem. The primary characteristic of our approach is that the calculation of the distance statistics for process monitoring uses MkNN rule instead of kNN. The advantage of the proposed approach is that the influence of outliers in the training data is eliminated, and the fault samples without MkNNs can be directly detected, which improves the performance of fault detection. In addition, the mutual protection phenomenon of outliers is explored. The numerical examples and Tenessee Eastman process illustrate the effectiveness of the proposed method.

We report a numerical study of an incoherently pumped fiber optical parametric oscillator. Following the convection-induced phase-locking mechanism, we show that the oscillating sideband can be grown into a higher degree coherence.

We present a numerical study on the coherent sideband generation from an incoherently pumped fiber optical parametric oscillator (FOPO). We revisit the fiber dispersion condition in a parametric process that fulfills the convection-induced phase-locking mechanism when pumping incoherently. Particularly, there exist analytical solutions for phase-matching frequencies in a convection-induced phase-locking process when using a parametric gain fiber with two zero dispersion wavelengths. With the optical feedback, we manage to circulate and amplify the convection sideband in a singly resonant FOPO. The autocorrelation shows that the coherence of the oscillating convection sideband can be strongly influenced by the cavity feedback fraction.

We propose a passively mode-locked fiber optical parametric oscillator assisted with optical time-stretch. Thanks to the lately developed optical time-stretch technique, the onset oscillating spectral components can be temporally dispersed across the pump envelope and further compete for the parametric gain with the other parts of onset oscillating sidebands within the pump envelope. By matching the amount of dispersion in optical time-stretch with the pulse width of the quasi-CW pump and oscillating one of the parametric sidebands inside the fiber cavity, we numerically show that the fiber parametric oscillator can be operated in a single pulse regime. By varying the amount of the intracavity dispersion, we further verify that the origin of this single pulse mode-locking regime is due to the optical pulse stretching and compression.

With the assistance of optical time-stretch using the lately developed free-space angular-chirp-enhanced delay cavity, we demonstrate the short pulse generation numerically by passively mode-locking a fiber optical parametric oscillator pumped by a quasi-CW pump.

The significant advance of power electronics in today’s market is calling for high-performance power conversion systems and MEMS devices that can operate reliably in harsh environments, such as high working temperature. Silicon-carbide (SiC) power electronic devices are featured by the high junction temperature, low power losses, and excellent thermal stability, and thus are attractive to converters and MEMS devices applied in a high-temperature environment. This paper conducts an overview of high-temperature power electronics, with a focus on high-temperature converters and MEMS devices. The critical components, namely SiC power devices and modules, gate drives, and passive components, are introduced and comparatively analyzed regarding composition material, physical structure, and packaging technology. Then, the research and development directions of SiC-based high-temperature converters in the fields of motor drives, rectifier units, DC–DC converters are discussed, as well as MEMS devices. Finally, the existing technical challenges facing high-temperature power electronics are identified, including gate drives, current measurement, parameters matching between each component, and packaging technology.

Feed conversion is an important production trait in turkey breeding; the measurement of an individual bird's feed efficiency is important in identifying the most genetically superior individual. The development of a real-time automated feed intake and body weight monitoring system is described in this paper. The system integrated multiple feed and body weight weighing stations consisting of electronic scales, radio frequency identification (RFID) devices and data communication modules. A distributed and client-server-based system architecture with multi-threading software design was developed. This system architecture allowed for a real-time data acquisition capability when a large number of stations were required. A structured query language (SQL) database management system was developed to record and manage the dynamic feed intake and body weight gain data of individual birds. The developed system also offers a powerful research tool for studying poultry feeding behavior under group housing conditions.

Faced with the fact that training samples belonging to a normal operation status are much more than the ones belonging to an abnormal operation status, we present the weighted support vector machine method. When the weights of the penalty parameters for different classes satisfy a relation equation, the undesirable effect caused by the unbalanced training class size is reduced, and classification accuracy of an abnormal operation status is improved. Simulated experiments for the data of Wisconsin diagnostic breast cancer (WDBC) show the effectiveness of the method.

With the increasing applications of real-time multimedia on Internet, an ECN-based TCP-friendly congestion control (ETCC) scheme was proposed, in which both end host and router were involved. RED was adopted in the router, and early congestion state was notified to the sender using ECN. Sending rate could be adjusted according to the rate scheme in the end host. The simulation showed that ETCC could adjust sending rate smoothly, decrease delay and packet loss ratio while maintaining good TCP-friendliness.