Advanced Materials Research Vols. 463-464

Abstract: The paper presents the results following the theoretical research of one vertical elevation mechanism regarding the dynamic behavior for one modern transfer systems, a manipulator or robot in cylindrical co-ordinates, which belongs to a molding technological module based on the hydraulic presses. Using the mathematical modeling and the computer simulation, it can identify the parameters with sensitive behavior and, finally, it can optimize the dynamic regimes according to the real requests of driving.

Abstract: One purpose of this study lies in presenting a method of detecting the distance and recorder it, between the mobile robot and obstacles, and in the same time the possibility of implementing in order for it to be used by individuals (subjects) in applied studies. Another purpose it is to present the main issues that might appear during the experimental analysis of a mobile robot.

Abstract: The main objectives of this paper are to provide an overview of the current progress of Internet of Things oriented technologies and to propose a framework which will enable the transformation of real world objects into intelligent virtual objects and allow for a simplified robot to object interaction.

Abstract: To release the connection problem between two different wireless communication technologies in conventional smart home system, a new embedded wireless smart based on PXA270, Zigbee and GPRS was designed. Web server was built on embedded system which uses PXA270 as core, and the exchange of information between internal network and the Internet via Zigbee module and GPRS module. ZigBee network mainly for short-distance communication and the GPRS network mainly for long-distance communications, so they can on the basis of complementary advantages to achieve a long-distance data transmission linked together by gateway. This paper presents the hardware architecture and the software implementation process. The experimental results show that this system has advantages of high reliability and low cost, so it can be applied to environmental monitoring and the smart home system

Abstract: In this study, the junction temperature (T_j) and thermal resistance (R_th) of five high-power multi-chip COB (chip-on-board) LED packages with different chip spacings were compared. The actual T_j was measured by an IR camera and compared with the simulation results from a computational fluid dynamics (CFD) software. In addition, the effects of heat slugs with different thermal conductivity, heat sinks of various thicknesses, chip size, and forced convection cooling on the T_j and R_th of high-powered LED components were investigated. The experimental results show that smaller chip spacing resulted in higher T_j and R_th. The heat dissipation performance can be improved by using a heat slug with a high thermal conductivity; and increasing the thickness of the heat sink, or employing forced convection cooling.

Abstract: This essay aims to introduce development of gate dielectrics. In present-day society, Si-based MOS has met its physical limitation. Scientists are trying to find a better material to reduce the thickness and dimension of MOS devices. While substrate materials are required to have a higher mobility, gate dielectrics are expected to have high k, low Dit and low leakage current. I conclude dielectrics in both Si-based and Ge-based MOS devices and several measures to improve the properties of these gate dielectric materials. I also introduce studies on process in our group and some achievements we have got. Significantly, this essay points out the special interest in rare-earth oxides functioning as gate dielectrics in recent years and summarizes the advantages and problems should be resolved in future.

Abstract: The influence of the aperture of transducer on the photoacoustic imaging was analyzed in this paper. We used different lengths of the same absorber for experiments, and these results demonstrated that the signal intensity would become stronger with the increasing of length of the absorber. But it will remain the same when its length over a certain value.

Abstract: In buck converter, the reverse recovery failure may cause electrical spikes and deteriorate the circuit performance. In this paper, the snubber circuits for FRD in Buck converter are presented and the simulation and experimental study are investigated. RC snubber, saturated inductance snubber and RCD snubber are developed and simulated by PSpice to reduce the voltage spikes of FRD. The comparisons of the voltage spike show the advantages of the snubber circuit for the reverse recovery failure of FRD. In a Buck converter experimental system with RCD snubber circuits, the measured voltage show that the voltage spike of FRD can be suppressed effectively. Simulation and experimental results prove that the snubber circuits presented is easy to implement and can improve the buck converter performance

Abstract: Subject to protection of power system, the article analyzes the communication technologies suitable for the current WAPS like IP exchange technology and MPLS etc. and analyzes the feasibility of these technologies in the field of power system WAPS. After comparative analysis of the current communication means, i.e. physical media and communication model etc., the article proposes a WAPS communication network scheme based on MPLS technology. Finally, the article uses network emulation software OPNET to simulate the communication performance of this communication scheme, compares it with current WAPS communication networks and gets the conclusion that the proposed wide area communication network scheme meets WAPS communication requirements

Abstract: The solution treatment and solution and aging treatment (T6) were disposed on 7050 aluminium alloy, then local processed by laser shock processing (LSP) with high-rate neodymium glass laser. The microhardness and residual stress on the surface of 7050 aluminium alloy were tested, then how the microstructure influences the residual stress on the surface of 7050 aluminium alloy by laser shock processing was analysed. The results show that the microhardness and residual compressive stress on the surface of 7050 aluminium alloy treated by solution and aging treatment was higher, and decreased obviously treated by solution treatment; the microhardness and residual compressive stress on the surface of 7050 aluminium alloy increased obviously by solution treatment and solution and aging treatment after laser shock processing; treated by solution treatment and solution and aging treatment, the microhardness and residual compressive stress of the material with uniform original structure was higher than the material with nonuniform original structure.