Applied Mechanics and Materials Vols. 462-463

Abstract: The inverted pendulum is a typical, multi-variable, nonlinear, strong-coupling, twirling and unstable system. Several intelligent-control strategies such as PID, feedback+Fuzzy and anfis neural-fuzzy were used to control the rotational inverted pendulum. The feasibility and validity were indicated by the simulation.

Abstract: The equivalent circuit model of shielding effectiveness of the cylindrical cavity with apertures against the near-field waves of electric dipole is established. The analytical formulas for approximately calculating the shielding effectiveness are given by the adjusted transmission line method. It is shown that the near-field shielding effectiveness of a cylindrical cavity with apertures is far inferior to that of far-field. The near-filed SE of the cylindrical cavity increases with the distance between the diploe and the apertured cavity, but when the distance is greater than a half wavelength of the electromagnetic disturbances, the SE tends to be saturated. In the cavity, the electric SE increased with the distance of observation points to the apertures. Results of the adjusted TLM are in good agreement with the CST simulation results.

Abstract: This research applies Six Sigma approach in order to reduce defect by increasing the assembly process capability index (Cpk) of Integrated Circuit (IC) production process. This study applies five phases (DMAIC) of Six Sigma approach beginning with define (D), measure (M), analyze (A), improve (I) and control (C) phases, respectively. The response of the research identified in the define phase is the chipped width with Cpk of 0.66 determined from the measure phase. The half-factorial experiments are implemented in the analyze phase to find the significant factors which are water temperature, water pressure and feed rate. In improve phase, the additioanl expriments are performed according to the Box-Behnken design in order to determine the non-linear relation between the chipped width and all mentioned factors. The optimal setting of each factors are determined by applied the response surface optimizer. Under the optimal setting, the control charts are used in the control phase to monitor the chipped width. The resulted Cpk of the response is increased to 1.39 which is greater than the one-sided accpetable process capability of 1.25.

Abstract: Lightning is the main reason to cause line tripping and service interruption, and its surge wave invaded into substation over the line is also the key factor which impact on the safe operation of equipments. Research on over-voltage transmission of lightning will be benefit to measure the lightning interference impact on energy metering equipments. Analyzing the transient process of the transmission line must adopt the telegraph equations. In this paper, the partial differential equations were discrete with the FDTD method. Then the equivalent power source of lightning is added at the starting point and the purely resistive load is added at the terminal. Finally, the transient propagation process of lighting was simulated in MATLAB. The three type of lossless non-uniform, lossy uniform or non-uniform transmission lines were considered.

Abstract: A novel multi-finger power SiGe heterojunction bipolar transistor (HBT) with segmented emitter fingers and non-uniform emitter finger spacing was proposed to improve the thermal stability. Thermal simulation for a five-finger power SiGe HBT with novel structure was conducted with ANSYS software. Three-dimensional temperature distribution on emitter fingers was obtained. Compared with traditional emitter structure, the maximum junction temperature of novel structure reduce significantly from 429.025K to 414.252K, the thermal resistance reduce from 159K/W to 141K/W, temperature distribution were significantly improved. Thermal stability was effective enhanced.

Abstract: A novel kind of high birefringent terahertz (THz) photonic crystal fibers (PCFs) with material-filled structure is proposed in this paper. Based on the material-filled technology, which different materials are selectively filled into four air holes of the inner first circle near the central core in the designed THz PCFs, high birefringence are obtained from the structural and material-filled induced asymmetry in large frequency ranges near 1THz. Modal birefringence with different structural parameters and diverse refractive indices of the filled materials are investigated by plane wave expansion (PWE) method. The numerical results show that high birefringence up to 10^-3 can be obtained and its structure is simpler than that of the early proposed highly birefringent THz PCFs. It is helpful for PCFs design and real fabrication in the potential THz applications.

Abstract: The Universal Serial Bus Transceiver is one of the important functional blocks of USB controller, which can transmit and receive data to or from USB devices. In this paper, USB Transceiver is designed and implemented with Verilog HDL, This includes functions such as, data serialization, bit stuffing, NRZI encoding and NRZI decoding, bit destuffing, deserialization. The transceiver is simulated by the modelsim software and the simulation wave is gave.

Abstract: A high-accuracy and robust LDO was designed based on CSMC 0.5um 40V BCD process, it was integrated in an outdoor decorative lighting LED Control and Driver SOC. The input of SOC was a 12V~40V power which was used by LED lamp. The LDO converted the input power of SOC to a 5V power for the Digital Control and Signal Transmission circuits inside the SOC. Due to the application requirements of SOC, the robustness of LDO in-55°C~150°C temperature and 12V~40V power voltage conditions must be guaranteed. The process variations and application conditions would affect the output voltage of LDO, 3 bits digital trim signal Trim [3: and a trim circuit were utilized to improve the accuracy of LDOs output voltage. Simulation result shows that the LDO works robustly and the output voltage accuracy can be improved to ±0.5% max in all conditions after being trimmed.

Abstract: In order to realize multi-carrier transmission of MPPSK modulation, a method was proposed after analyzing the cause of the internal channel interference (ICI) among multi MPPSK signals. The ICI was eliminated by reducing the modulation order of each MPPSK signal to a certain level and modulating MPPSK signals to different parts of a same symbol cycle. The information rates of single carrier modulation and multi-carrier modulation were compared to illustrate the role of order reduction. The BER performances of single carrier modulation and multi-carrier modulation were also carried out by simulations. Results show that: the proposed method can achieve MPPSK multi-carrier transmission, with higher information rate than that with single carrier modulation and no BER performance loss, which is expected to be an available scheme for improving spectrum efficiency.

Abstract: A high precision FIR digital filter is achieved based on CSD code. The characteristic of CSD coding is described and the structure of the FIR filter based on time division multiplex is given. FIR filter coefficients is generated by fadtool of MATLAB . The digital filter module is designed by Verilog HDL and simulated under QUARTUS II and MATLAB environment. The results show that the design can improve the accuracy of data acquisition significantly and reduce the use of FPGA resource.