运动基飞行训练模拟器技术研究分析

本文基于我国航天飞行训练的任务需求和发展现状,深入分析了国内外运动基模拟器在飞行训练中的应用经验和研究成果,着重讨论了运动基模拟器的技术基础以及在工程应用中的关键技术,并对运动基模拟器在我国航天飞行训练中的应用进行了展望。

现代船舶轮机模拟器的应用与发展

针对现代船舶轮机模拟器在船员培训与航海教育中的应用现状,分别从船舶轮机模拟器的概念、特点、研究目的及国际公约或规范对船舶轮机模拟器功能上的要求、国际公约或国内法规对航海类院校关于应用轮机模拟器开展培训的强制性规定、国内外船舶轮机模拟器的研发现状以及正在研发使用的最新理论和技术进行归纳分析,最后结合最新的应用处理技术以及新形势下的特殊需求对未来船舶轮机模拟器的发展作出展望。

Dynamips模拟器在高职高专院校的应用

现今在高职高专院校,十分注重学生的实践能力的培养,为社会输送技能型人才,本文分析了现今学校中网络设备不足的情况,学生实验受到设备数量的制约,影响学习效率,由此提出了利用Dynamips虚拟化技术模拟器进行辅助教学的可行性和优越性,从而能够促进课程的改革,带来创新。重点介绍了使用Dynamips模拟器进行实验的方法和思路,和它的实验体系结构,功能模块。

The System Design of Semiconductor Device Simulator

This paper studies the numerical simulation for semiconductor devices and discusses the software design of the simulation system. Our focus is on the deep submicron device simulation for BJT, MOSFET, heterojunction bipolar transistors (HBT), etc. So the object oriented technology for software design and its realization is used to make the system easy to implement, maintain and extend. Besides the discussion of simulation and software system design, this paper introduces a device simulator SMDS and its parallel extension under local network environment using CORBA technology.

迪斯尼与Linux

去年年中，当位于加利福尼亚伯班克市的迪斯尼动画制作公司（Walt Disney Feature Animation）宣布使用Linux制作数字动画时，很多人认为Adobe公司会因此将其产品迁移至Linux平台之上。然而，时至今日，Adobe在这方面似乎毫无动作。在长期等待却没有什么结果的情况下，

Neural Network Based Algorithm and Simulation of Information Fusion in the Coal Mine

The concepts of information fusion and the basic principles of neural networks are introduced. Neural net-works were introduced as a way of building an information fusion model in a coal mine monitoring system. This assures the accurate transmission of the multi-sensor information that comes from the coal mine monitoring systems. The in-formation fusion mode was analyzed. An algorithm was designed based on this analysis and some simulation results were given. Finally,conclusions that could provide auxiliary decision making information to the coal mine dispatching officers were presented.

A new accelerating algorithm for multi-agent reinforcement learning

In multi-agent systems, joint-action must be employed to achieve cooperation because the evaluation of the behavior of an agent often depends on the other agents’ behaviors. However, joint-action reinforcement learning algorithms suffer the slow convergence rate because of the enormous learning space produced by joint-action. In this article, a prediction-based reinforcement learning algorithm is presented for multi-agent cooperation tasks, which demands all agents to learn predicting the probabilities of actions that other agents may execute. A multi-robot cooperation experiment is run to test the efficacy of the new algorithm, and the experiment results show that the new algorithm can achieve the cooperation policy much faster than the primitive reinforcement learning algorithm.

Numerical simulation of the anti-shock performance of a gear case

Both sea battles and testing of ship in underwater explosions reveal unacceptably poor anti-shock performance of important shipboard equipment. Anti-shock performance of shipboard equipment is a significant factor determining fighting strength and survivability. The anti-shock performance of a shipboard gear case based on BV043/85 was investigated using numerical simulation. A geometric model of the gear case was built using MDT software and meshed in HyperMesh software, and then the finite element model of the gear case was formed. Using ABAQUS software, the anti-shock performance of the gear case was simulated. First, shock response of typical regions of gear case was determined. Next, some generalizations were made about the anti-shock performance of the gear case by analyzing the Mises stress of typical regions varied with shock inputs. Third, weak regions were determined from simulation results. The threshold values of shock resistance of the gear case at different impulse widths were obtained through interpolating the numerical simulation results selected from the most dangerous spot. This research provides a basis for further optimization of the design of gear cases.

Modeling and simulation of Cobot based on double over-running clutches

In order to analyze characteristics of Cobot cooperation with a human in a shared workspace, the model of a non-holonormic constraint joint mechanism and its control model were constructed based on double over-running clutches. The simulation analysis was carried out and it validated passive and constraint features of the joint mechanism. In terms of Cobot components, the control model of Cobot following a desired trajectory was built up. The simulation studies illustrate that the Cobot can track a desired trajectory and possess passive and constraint features ; a human supplies operation force that makes Cobot move, and a computer system con- trois its motion trajectory. So it can meet the requirements of Cobot collaboration with an operator. The Cobot model can be used in applications of material moving, parts assembly and some situations requiring man-machine cooperation and so on.

Electro-Mechanical Phase Shifters Based on MEMS Structure

The aim of the study of phase shifter on MEMS （micro-electro-mechanical systems） structures was to minimize the dimensions of the design achievement. Also, the main task was to achieve the reliability and durability of the device. The calculation was based on the optimization technique （step by step） and the modeling of individual parts of the device, namely MEMS-keys that perform the main function--switching. The urgency of this problem is the development and study of one device as a universal, that is, automatically switches from two signals simultaneously. Designs are original and devises are the intellectual property of the authors. The program for modeling phase shifters Computer Simulation Technology Microwave Studio and its results are presented in the paper.

Flow Field of Circulating Fluidized Bed Reactor with Venturi Inlet Configuration

Different two-equation k-ε models were used to simulate the gas flow field generated by a new type of circulating fluidized bed reactor with venturi gas distributor. The numerical results were compared with the experimental data. It has been shown that the simulation results from the standard k-ε model have the best match with the experimental data. Based on this model, the gas flow field in the venturi diffuser and riser was analyzed by the concept of velocity nonuniformity and dead zone percentage. Both the nonuniformity of gas velocity and the dead zone percentage reach the maximum at the venturi outlet due to the effect of the vortex. At the same time, it provides a good platform for the further optimization of the inlet configuration of circulating fluidized bed reactor.

Realization of a tunable analog predistorter using parallel combination technique for laser driver applications

This paper describes a new approach for designing analog predistorters that can compensate for the nonlinear distortion of laser drivers in a radio-over-fiber （RoF） system. In contrast to previous works, this paper analyzes the transfer characteristics of CMOS transistors, by combining parallel currents of CMOS transistors in various W/L and negative bias voltages to realize the tunable analog predistortion function. The circuit is fabricated by a standard 0.18txm CMOS technology. The core circuit current consumption is only 15mA and the entire driver circuit works in a band-pass from 1 - 2.2GHz. Experimental results of two-tone tests have shown that with an analog predistortoer the IIP3 of the laser driver circuit has an improvement of 4.91 dB.

Feedback Filtering for Digital Control Applications

Thanks to the progress in semiconductor technologies, today microcontrollers offer huge computational power. That allows using advanced control algorithms with a built-in intelligence with a sufficient speed, for many demanding applications. These capabilities make the embedded control ideal for using at complex plants and for obtaining the highest performance in a wide area of operations. However, control performance also strongly depends on the feedback. A short latency and a high precision of embedded analog peripherals allow building fast and accurate control loops. The paper proposes an easy design method of high performance analog to digital converter filtering path, optimized for control applications.

Ultrasonic Sensors with Mechanical Couplers： Simulation and Validation

The use of ultrasonic sensors has varied applications, but the sensor operation frequency limits the operating distance. An easy way to increase this distance is to couple a mechanical element （horn）, but it is necessary to characterize this technique. In this paper the results obtained in a study of the behaviour of mechanical elements coupled to an ultrasonic sensor using finite element techniques are presented. These results have been obtained using Comsol Multiphysics modelling. Also, the effect caused by the sensor size on the radiation acoustic pressure has also been evaluated. In other way, in this paper it is presented the results obtained in the laboratory measurements. First, it is studied the influence of a straight horn attached to the ultrasonic sensor. Later, it is presented the variation in the sound pressure on the radiation axis when the sensor varies its size. In the final part of the paper, the experimental validation of the simulations is presented.

Experimental and numerical investigation of a solar eductorassisted low-pressure water desalination system

Greenhouse solar-energy driven desalination technology is potentially well suited for supplying water and small scale irrigation in remote and/or rural areas, and for avoiding over-exploitation of available water resources. The efficiency and productivity of these systems are however low, in part because the heat of evaporation has to be transferred as waste heat to ambient air during condensation. In order to maximize energy regeneration during condensation we propose an educator based system that lowers the evaporation process temperature by reducing pressure. The feasibility of the educator assisted passive solar desalination system is investigated using a detailed computational fluid dynamics analysis complemented by experiments. The study focuses in particular on the ability of the new design to lower the required evaporation temperature and thereby reduce the energy intensity of the process. Two configurations, with open and closed educator, are investigated and a detailed analysis of the thermofluid processes is presented. The configuration with a closed educator installed outside the evaporation chamber shows very promising performance. The proposed system can maintain the maximum temperature and pressure in theevaporation chamber below the desirable temperature and pressure thresholds （30 ℃ and 5 kPa）. The analysis and experimental data also show it is possible to further reduce energy requirements by reducing the motive water flow rates.

Water-trapping and drag-reduction effects of fish Ctenopharyngodon idellus scales and their simulations

In the last decades, surface drag reduction has been re-emphasized because of its practical values in engineering applications,including vehicles, aircrafts, ships, and fuel pipelines. The bionic study of drag reduction has been attracting scholars' attentions. Here, it was determined that the delicate microstructures on the scales of the fish Ctenopharyngodon idellus exhibit remarkable drag-reduction effect. In addition, the underlying drag-reduction mechanism was carefully investigated. First,exceptional morphologies and structures of the scales were observed and measured using a scanning electron microscope and3-dimensional(3D) microscope. Then, based on the acquired data, optimized 3D models were created. Next, the mechanism of the water-trapping effect of these structures was analyzed through numerical simulations and theoretical calculations. It was determined that there are many microcrescent units with certain distributions on its surface. In fact, these crescents are effective in generating the "water-trapping" effect and forming a fluid-lubrication film, thus reducing the skin friction drag effectively.Contrasting to a smooth surface, the dynamics finite-element analysis indicated that the maximum drag-reduction rate of a bionic surface is 3.014% at 0.66 m/s flow rate. This study can be used as a reference for an in-depth analysis on the bionic drag reduction of boats, underwater vehicles, and so forth.