Applied Mechanics and Materials Vols. 271-272

Abstract: This paper puts Internet of Things in a wider context: how it relates to the monitoring system for equipments in the workshop in the manufacturing domain and how to apply IOT along with other new techniques for developing new monitoring system for equipments in the workshop, and proposes the necessity of developing closed-loop monitoring system for equipments in the workshop based on IOT. In this paper, the concept and constitution of closed-loop monitoring system for equipments in the workshop based on IOT is presented, systematic basic working principle and hardware structure topological graph is given, implementation methods of each component of the system are introduced. The closed-loop monitoring system for equipments based on IOT given in the paper can ensure the safety of plant and its circumambience and reduce the loss of fault. It is a typical application of IOT in the manufacturing domain.

Abstract: Traditional heat-exchanger can ensure the air in chamber a specific bulk temperature, but cannot guarantee the temperature distribution is even. A heat exchanger and temperature homogenization device was designed to precisely adjust the temperature and temperature uniformity of airflow. The device was made up of several parallel processing units. Each unit was an independent heat exchanger with temperature homogenization function. To improve the design of the device, evaluation indexes were proposed for both heat transfer capability and temperature uniformity of the airflow field. Analysis and comparison of 3D numerical simulations using FLUENT were made to figure out the optimal way. The model proposed can provide guidance for practical applications. The final results indicate field synergy principle can be used to analyze the temperature homogenization of airflow.

Abstract: Two kinds of efficient electrostatic discharge (ESD) protection circuits in lateral drain extended MOSFETs (DEMOSFETs) will be designed and investigated in this paper. One kind of these test samples is fabricated with an SCR structure, which has the lowest turned-on resistance when it is triggered by a high voltage of ESD event. The SCR circuit is the most efficient of all protection devices in terms of ESD performance per unit area. Furthermore, the other type of these DUTs is an SCR with RC-triggered structure, which will have a small trigger voltage (Vt1) under ESD event, and then it obtains a good ESD immunity level.

Abstract: By use of finite element method to analyze the strength of 6-wing synchronous rotor, and illustrate the change of parameters regarding strain, stress and displacement etc. so as to visually see whether the designed rotor will reach the design requirements; meanwhile, through structural analysis, to provide guidance for the further optimization of designing for 6-wing synchronous rotor.

Abstract: Multispan rotor system(H858 compressor) is studied in this paper. Based on the rotor dynamic theory, complex rotor system is simplified reasonably, and finite element model is established using finite element software(MSC.Patran&Nastran). The natural frequencies are obtained in the condition of bending vibration, and the functions of frequencies and variables are matched on the basis of the artificial neural network (ANN) technique. With the criterion that the absolute value of the difference between the natural frequency and forcing frequency, the reliability mode and the systems safety probability are defined, then the frequency reliability sensitivity analysis method is presented. And the equations of the related sensitivity with respect to mean values and variances are mathematically expressed. The reliability and sensitivity of rotor system are analyzed, which demonstrate the effectiveness and accuracy of the proposed method.

Abstract: In order to study the atomization mechanism of gas-liquid two-phase flow, high speed camera was used to photo the water-jet, the jet images at different time were gained, CFD technology was used to simulate the launch process of water cannon in 3-D Model, Large Eddy Simulation and VOF model were used to describe the turbulent flow and track the gas-liquid interface in and out of launch pipe. The gas-liquid distribution image of experiment and simulation, water-jet velocity of experiment and simulation both matched well with other. The simulation results show that the flow pattern in launch pipe of water cannon changed from atomization pattern to annular pattern and finally slug pattern, the conclusion has significant meaning to the study of second spray and first atomization of water-jet.

Abstract: This paper mainly imagined and designed a bionic impeller with arc shape lamina especially little arc lamina, researched on its hydrodynamic performance on the base of the prior hydrodynamic performance research on straight panel shape lamina. Applied FLUENT software to gain the figures on lift force, propulsion, pressure nephogram, velocity diagram and volume fraction distributing of bionic impeller when depth h is at -7.5 cm, 0cm and 7.5 cm, discussed and analyzed the rules of hydrodynamics when h was altering, tamped the groundwork of optimizing the externality design of the bionic impeller further.

Abstract: This paper studies the thermal flow concentration near an interface crack in a layered medium. Solution method for the thermal flow intensity factor is established. Both the Griffith crack and the penny-shaped crack are studied. Limiting cases of the current problem include (1) the solution of crack problem associated with classical Fourier heat conduction, (2) the solution of an interface crack in an infinite layered medium, and (3) the solution of a crack in a homogeneous medium.

Abstract: In this paper, we propose an improved channel estimation method for orthogonal frequency division multiplexing (OFDM) systems in sparse multipath fading channels. The proposed method transforms the channel estimates into an ordered space and uses the minimum description length (MDL) criterion to estimate the number of paths and the path positions. Simulation results demonstrated that an improved channel estimation performance is obtained due to the reduction of signal space.

Abstract: In modern society, people have not only the functional requirements of the product, but also the pursuit in its spiritual sustenance. Based on the concept of the folding structure, this thesis extracts the essence of the folding structure design from typical product design, then analyzes the style and structural features of range hood in depth, puts forward the design concepts and innovative solutions of range hood, and, designs a pull-out range hood which saves space and achieves a combination of Chinese traditional elements with modern design perfectly.