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Axial piston pumps have been widely used in aircraft hydraulic systems to supply the system with pressurized fluid. The continuous improvement of the aircraft performance has put forward the demand on aviation piston pumps for high power density, safety, and reliability. The lubricating interfaces in axial piston machines are the key design issue that greatly determines the pump performance and service life. The cylinder block/valve plate interface is one of these critical lubricating interfaces and has received considerable attention from many researchers in the last half century. This study aims to review the state‐of‐the‐art literature on the cylinder block/valve plate interface comprehensively and systematically. First, we introduce various theoretical models developed to investigate the lubrication behaviors of the interface and compare them in terms of their assumptions and limitations. Second, the experimental studies on the cylinder block/valve plate interface are presented comprehensively, where the involved test rigs are divided into three types according to their fidelity levels and measurement functionality. Third, we summarize some typical approaches of structure optimization, surface shaping, and surface strengthening, which help improve the load-carrying and anti-wear capacities of the interface under severe operating conditions. Finally, the challenges and future trends of the cylinder block/valve plate interface research are discussed briefly.

Aiming at the problem that the Firefly algorithm (FA) is prone to fall into local extremum, low precision and slow convergence speed, an improved Firefly algorithm (OLLevyFA) based on reverse learning initialization and Levy perturbation mechanism is proposed on the basis of the Firefly algorithm (FA). Through the calculation of nine typical test functions, the FA algorithm, LevyFA algorithm and OLLevyFA algorithm compared and verified. The results show that compared with the FA algorithm, the LevyFA algorithm and the OLLevyFA algorithm can jump out of the local optimum more effectively, and the OLLevyFA algorithm has the characteristics of higher precision and faster convergence speed. Finally, the FA algorithm, LevyFA algorithm and OLLevyFA algorithm are put into the magnetization temperature measurement model. The comsol software is used to simulate the calculation results and the results of the particle swarm optimization algorithm. The results show that the results of OLLevyFA algorithm have higher precision and can meet the requirements of the system.

In this paper, a new method to set up the static magnetic field of the targeted magnetic fluid hyperthermia is presented based on the study of magnetic nanoparticles and biological heat transfer mechanism. Magnetic field generating system consists of 8 coils, deployed in the lesions of the peripheral symmetric space, the principle is to heat magnetic nanoparticles by high frequency alternating magnetic field, which kills the cancer cells, while building a static magnetic field in the periphery of tumor region to protect healthy tissue from harm. The invention can solve the technical problem that the heating area of the hyperthermia structure is not completely controllable.

To enhance the exhaust efficiency during ventilation, three types of air duct outlets were imported. According to the characteristics of velocity distribution simulated by numerical method, the flow field is divided into the mixing zone and the exhaust zone. The gradual contracted air duct outlet can enhance the mixing effect between fresh air and smoke. In the exhaust zone, however, the flow velocity on the upper section of the tunnel is weakened, which is unfavorable for smoke exhaust. Gradual expanded air duct outlet, on the contrary, may weaken the concentration effect of the airflow. The flow velocity on the upper section of the tunnel is increased in the exhaust zone, thus the flow field is more homogenized, which is in favor of smoke exhaust.

In computer network communication, adopted the error-check control methods to reduce the error code frequency of data transmission commonly. The CRC (Cyclic Redundancy Check) method is the best one of them. This paper analyzed the principle and the check rules of CRC algorithm. For the CRC algorithm of bytes operation, proposed a new table-driven algorithm which is visual, compact and easy to be understood. A strict mathematic proof of the CRC algorithm is given. By diagrammatizing, deduct the calculated process of CRC-ITU and CRC-32 code in detail. At the same time, we designed a concise CRC-ITU algorithm with assembly language similarly, and discussed the method using the remainder of F(x)/G(x) as a surveillance code briefly.

Analytical simulation is an important method to study CT reconstruction algorithm, which can quickly and effectively demonstrate the effectiveness and accuracy of the reconstruction algorithm. According to the basic process of CT detection and the main frame, which includes model generation, parallel beam scan projection data acquisition, common analytic algorithm of image reconstruction and image post-processing and analysis, the parallel beam CT analytical simulation software platform is developed by C++ language. The setup interfaces for main parameters of each link are reserved, so the key items of the simulation process can be selected and adjusted, which carries out a flexible simulation study based on the CT platform. Finally, an example of reconstruction simulation for tubular object based on angle sparse projection data from parallel beam CT is given, which verifies the practicability of the simulation software platform.

In this study we analyze the signal in measurement system with distributed optical fiber sensors. The display signal is defined by the user not for general custom. The data of for-processing-part are processed regularly, which directly provides results for the user from the monitoring system. These results go into the next step to add environmental parameters, which includes weather, special events and season information. Information fusion and matching operation of the result and environment information enhances the accuracy of hidden hazard early warning.

The integrated electro-hydrostatic actuator (EHA) with variable displacement and variable rotation speed is researched. In the system, the output of the actuator is changed by controlling the rotation speed of the brushless DC servomotor and the displacement of the servopump. The mathematical model described in state space model is created. The system characteristics are studied based on the point of multiplicative dual variable. And the basic method of control of the system is presented.

In this paper, we shall prove that for any orientable 3–manifold M, there is a link L = K ∪ K1 ∪ K2 ∪ K3 with four components in M, such that the complement of L, say ML, contains separating essential closed surfaces of all positive genera.

China is arguably one of the countries where the most tunneling and underground projects are being performed. Recently in China, it has often been necessary to construct tunnels under many types of conditions and to develop new techniques. Currently, some advanced construction techniques cannot be appropriately applied to different types of underground conditions, and many traditional methods are still often used. However, because of the progress in tunnel boring machines (TBM), innovations are required for the construction method. This article introduces the current situation of TBM both in western countries and in China, and examines the future of TBM in China.

A new method to set up the static magnetic field of the targeted magnetic fluid hyperthermia is presented, and a new particle swarm optimization algorithm with Levy flight (LF-PSO) is proposed. Magnetic field generating system consists of 18 coils, deployed in the lesions of the peripheral symmetric space, the main principle is to heat magnetic nanoparticles by high frequency alternating magnetic field to kill the cancer cells, while building a static magnetic field in the periphery of the tumor region to protect healthy tissue from harm. Tumor location information may be shifted, so each treatment needs to reconfigure the static magnetic field. The set of magnetic heating coil currently adopted this new LF-PSO algorithm, in the reason of the particle swarm optimization algorithm with Levy flight mechanism is characterized by good robustness, high precision of optimal search and it is easy to jump out of local optimum. Experimental results show that by building a new objective function, and comparing with the FEM algorithm, the LF-PSO algorithm has advantages of fast solving speed and high accuracy.

In this paper, based on the mechanism of CCD camera, an event-based simulation method of γ-ray-induced transient noise was developed, which applying MCNP5 Code based on Monte Carlo methods. On the mono-energy γ-ray sources, the transient noises of two different CCD cameras have been measured at different doses (from 0.001mR to 1mR) and different incidence angles. The 60 Co and 137 Cs were used as the mono-energy γ-ray sources, and the Compton Scattering technique were adopted to get lower energy γ-ray sources. In order to get the pure transient noise induced by γ-ray, a method was advanced for extracting the transient noise from the image mixed the background noise. And the transient noise was characterized, including the number of noise clusters, the noise intensity spectrum and the size spectrum of noise clusters. The variation characteristics of noise have been draw from the simulation and experiment, which induced by γ-rays of different dose, or different energy or different incidence angle.

The adsorption isotherms of cetyltrimethylammonium ion (CTA+) together with that of the Br counterion on silica gel, and the effects of pH and added salts (NaF, NaCl and NaBr) have been systematically determined at 25°C. Electrophoretic mobilities of the silica gel particles have also been measured in the same conditions. The adsorption isotherm of CTA+ consists of four regions. Region I, at low concentrations of surfactant, the adsorption results primarily from electrostatic force between CTA+ and the negatively charged silica surface. Region II (first plateau), at medium concentrations, the adsorption is due to both the electrostatic force and the specific attraction (vdW forces) between CTA+ and the surface. Region III, characterized by an abrupt increase in the slope of the isotherm when the concentration reaches a particular point known as hemimicelle concentration (HMC). The abrupt increase in the adsorption is due to the hydrophobic interaction between hydrocarbon chains. Region IV (second plateau), at or above CMC, the limiting adsorption is reached as the micelle is not adsorbed. Based on this model, the experimental results can be explained reasonably. The results show that the HMC is about half of the CMC. According to the assumption that each adsorbed CTA+ ion in the first plateau is an active center for surface aggregation, the average aggregation number of hemimicelle have been calculated.