Applied Mechanics and Materials Vols. 475-476

Abstract: Inductive loads are common in the real time monitoring system of aircraft engines. The excitation for these loads is better to chose current source. A stored program control interchange current resource based on DDS and current feedback amplifier was designed for these loads. When the output frequency of the resource was chosen 5kHz, the export current can reach 10mA and the change of the amplitude is less than 1%.

Abstract: This paper presents an iterative method to solve the nonlinear dynamical system ofan electrostatically actuated micro-cantilever in MEMS. Different from someother iteration methods for nonlinear dynamical systems, no additionalprocedures have to be carried out to eliminate the so-called secular terms. Inaddition, an efficient approach is proposed to expand fractional functions intotruncated Fourier series. That makes it possible to implement the iterativeprocedures. Importantly, all the iteration equations are purely linear. Numericalexamples show that the solutions provided by the method are in excellentagreement with numerical ones. The effects of applied voltage, cubic nonlinearstiffness and squeeze film damping on vibration responses are discussed indetails.

Abstract: The output characteristics of high power ytterbium-doped fiber super-fluorescent sources were analyzed. 75.7W output power can be achieved when the 915nm pump power is 100W, and the fiber length is 10m.when the pump power changes from 20 to 100W, the backward super-fluorescent power is always larger than the forward. The mean wavelength of the forward and backward super-fluorescent is very stable. The spectrum width all decrease. The spectrum width of forward ASE changes from 24.8nm to 21.4nm when the pump power changes from 20 to 100W. The spectrum width of backward ASE changes from 25.5nm to 22.3nm.

Abstract: Distributed Generation (DG) plays a more and more important role in the power system.When it is in the grid-connected mode,it has a great influence for security and stability of power systems.In order to determine the best position of DG when it is grid-connected,firstly,analyze the the steady of the system to define the candidates of DGs that will be grid-connected,then select some operation indicators to assess the power system using Interval Analytic Hierarchy Process (IAHP),finally decide the best position of DG. Modeling and simulation work are carried out in BPA,and the detailed steps of decision-making are given. The results show that the location of DG determined by this method of the paper can guarantee the security and stability of power systems and make grid in the optimal operation.

Abstract: In the complex electromagnetic environment, the cable is one of the paths through which the energy of electromagnetic interference (EMI) may couple into the electronic component and circuit in the shielding enclosure. A modified field-circuit method which combing the 2-port network theory and the mixed potential integral equation and the method of moments (MPIE-MOM) is presented to analyze the electromagnetic radiation effects of an enclosure with a cable under any form of electromagnetic interference. Taking the Gaussian pulse as an example, the electromagnetic radiation effect of the PCB in the enclosure is analyzed with the field-circuit method. The model presented in the paper is a theoretical reference for the design of the electronic equipment which working in the complex electromagnetic environment.

Abstract: Under analysis of the head-up display system working principle, this paper details the key technologies of automotive head-up display, such as micro-projection technology, image processing technology and networking interconnection technology. At last, the development trends was introduced in detail.

Abstract: CNC constant voltage power is composed by the analog power circuit, MCU control circuit , pulse width modulation circuit, a power driver amplifier , analog to digital conversion circuit , the input voltage setting circuit and the output voltage display circuit. The power possesses the functions of digital regulator, high precision output, short-circuit & over-current protection and alarm functions, especially for a higher accuracy requirements for various occasions.

Abstract: In this paper, a new method is brought to solve outside radio frequency electromagnetic environmental test of cascade system, which is becoming more and more import to meet electromagnetic compatibility requirements for systems. However, it is very difficult for comprehensive assessment as the volume size of cascade system is very big and irradiation spot of antenna is limited. Based on the theory of field line coupling and aperture-coupled, technology of injection and radiation, the difficulty of test is solved better.

Abstract: A bandgap reference without passive components based on standard CMOS is proposed. Using an improved inverse-function technique without any curvature-compensated techniques, two reference voltages are got in different temperature ranges. One is 1.56V with a temperature coefficient of 9.2ppm/°C in the range [0, 14 °C at 3.3V supply voltage, and the other is 1.546V with 47ppm/°C in [-25, 15 °C at 3.3V. Its PSRR (power supply rejection ratio) is below-60dB at 10kHz, and it is quite suitable for integration in processing circuits of MEMS (micro-electro-mechanical systems) devices.

Abstract: An Ultra broadband power amplifier module based on GaN HEMT is studied. TGF2023-02 Chip of GaN HEMT from TriQuint Corporation is adopted and modeled first. The amplifier is designed with negative feedback technique. DC bias circuits and microstrip matching circuits are simulated and optimized carefully. Simulation results show that the amplifier module has a wide range frequency response from 3 to 8 GHz. It exhibits power gain of 7.6 dB, an output power of 37.5dBm under DC bias of V_ds = 28 V, V_gs = -3.6 V at the frequency of 5.5 GHz.