Advanced Materials Research Vols. 694-697

Abstract: In this paper, the computational formula of field distribution in a coaxial waveguide and the field distribution, resonant frequency and Q factors of open coaxial resonator are introduced. The S21 and the field profile of the TEM mode in a coaxial waveguide, and the field profile and E-field of the mode in a coaxial resonator is gained by the software CST microware studio. The truth that an open coaxial cavity is virtually a slow-varied section coaxial waveguide is gained.

Abstract: A design of planar array modulation collimator is proposed for intensity-modulated radiotherapy. Target area is constructed by planar array of rectangle modules which support flexible adjustment. The structure and operation principle of collimator has been introduced in detail. Combination of this equipment with standard modern linear accelerators and MLC will be an ideal method to improve boundary conformity, reduce penumbra and dose leakage.

Abstract: According to the electric field intensity of oblique four-needle electrodes (OFNE) in biological tissue, the discrete equations based on the indetermination linear current density were established by the boundary element integral equations (BEIE). The non-uniform distribution of the current flowing from four-needle electrodes to conductive biological tissues was imaged by solving a set of linear equations. Then, the electric field intensity generated by OFNE in biological tissues at any point can be determined through the boundary element method (BEM). It means that this method has an important referenced significance for computing the electric field intensity generated by OFNE in bio-tissue.

Abstract: The charge pump, which is used to realize self-drive in power factor correction (PFC) converters working in critical conduction mode, was studied in this paper. The charge pump was a RCD network made up of a resistor, a capacitor and a diode, and could be divided into three kinds of modality. The state equation of each modality and the connection between them was build, and theoretical waveform was figured. The design guideline in form of equations was also proposed considering the voltage variation and the time constant of the charge pump. Finally, a 200W prototype was build, and the experimental results matches well with the theoritical analysis.

Abstract: This paper presents simulation of a three-phase single-level inverter. The inverter is designed to be fed into the power grid. State-space model and sinusoidal PWM technique are described in this paper. The simulation is based on Multisim and LabVIEW co-simulation. This method of SPWM simulation has some software and harmonic which must be taken into account while using it in the real power grid. Efforts are underway to improve the three-phase single-level inverter.

Abstract: A laser annealing system for the CMOS IC processing is setup, consisting of a solid-state laser, a beam delivery system, a 2D movable wafer stage, an auxiliary heating system, and a chamber that holds all the above modules. The complexity of the system makes it much difficult to achieve a stable performance. Each related process factor is deliberated, and the strategies controlling of theses process parameters are then determined. A reconciling control method to balance the effect of laser energy density and laser beam shape is considered to maximize total production and reliability. A piece of Matlab code is programmed to assess the controlling effect. We found from running the system that after combining these strategies, system stability is improved, and desirable laser annealing process effects can be promised.

Abstract: This article chooses PIC18F4620 as its key device and designs a waveform signal generator. It can improve the function of the waveform signal generator in hand. A lot of advantages are included in it, such as simple circuit, simple regulation and convenience maintenance. It can completely be used in industrial instrumentation and automatic testing area.

Abstract: The erbium doped fiber amplifier (EDFA) is one of the most important devices in the present optical communication and measurement system. However, the problem on parameters optimization of EDFA is always an open issue. Aim to obtain the output characteristics quickly and flexibly, in this article, we model the operation of an EDFA system by simulation. The numerical results show that the output spectrum of EDFA with various parameters. And through analyzing the performance in terms of gain, flatness and noise, the optimal pumping power and the length of EDF are determinate.

Abstract: An nMOS transistor in input/output pad as the ESD protection element is usually in the form of multi-finger layout. This paper will show simple but effective ways to improve an nMOSFET’s ESD robustness or LU immunity for use in I/O pads, i.e., the source-end layout influences on the protection components in ESD/LU capabilities of the input/output pads will be investigated. In other words, they are used to increase the effective ESD or LU capability of the ESD protection elements. Here, the different source-end layout types will be carried out the important snapback parameters. We focus on exploring the secondary breakdown current (I_t2) and holding voltage (V_h) for the ESD discharge capability and the latch-up immunity, hopefully, it does effectively enhance ESD/LU robustness.

Abstract: With the widespread popularity of wireless mobile devices, the demands of emerging applications have been proposed, such as video telephony and HD video play. The next generation of wireless mobile computing devices needs to have higher data transfer rate, more complex algorithms, as well as low power consumption. This paper gives out a variable-width SIMD processor architectures controller and data transfer module designing method. The controller designing focused on controlling the program flow and initializing the data transfer module. By simulating the architecture on Xilinx ISE Design Suite, the fundamental modules have been designed and tested. The results of simulation verify the correctness of the controller and data transfer module design.