Applied Mechanics and Materials Vols. 303-306

Abstract: The use of electromagnetic relief valve with high pressure and large flow rate in hydraulic system is usually easy to bring vibration and noise issues, especially while water or high water based fluid (HWBF) is used as the fluid medium. In this paper, a HWBF electromagnetic relief valve with a cushion valve was presented and its simulation model was built based on AMESim software. Through simulation, it is found that the cushion valve can significantly reduce the peak pressure gradient of the electromagnetic relief valve during unloading process compared with that without a cushion valve. This research provides a new solution for solving the vibration and noise issues of a hydraulic system with electromagnetic relief valve.

Abstract: A novel magnetoelectric tunable dual-band bandpass filter in which the processing core is based on a ferrite-piezoelectric layered structure is designed and characterized. The structure is consisted of bonded layers of single-crystal yttrium iron garnet film and single-crystal lead zirconate titanate slab (YIG-PZT). The tunability of the filter can be accomplished by magnetoelectric interaction between the YIG film and PZT film that manifests as a shift in the ferromagnetic resonance (FMR). Simulation results show a 24 MHz tuning range for E=-6～6 kV/cm, and the insertion loss of stop band is more than 34 dB, thus the filter can be applied to the working frequency band of TD-SCDMA in the wireless communication system.

Abstract: This paper proposes an innovative CMOS band-gap reference (BGR) topology with a curvature-compensation by using MOS transistors operating in weak inversion region. The mechanism is analyzed thoroughly and the corresponding BGR circuit has been implemented in standard CMOS 0.18u technology. The proposed BGR achieves 1.76 ppm/°C in the range of -40°C to 120°C at 1.2V supply voltage. In addition, it consumes only 30uA current.

Abstract: A novel structure of ESD protection device based on the static induction thyristors (SITh) was in further investigation. Detailed analysis of the negative resistance characteristics of SITh was presented, especially its blocking and conducting states that satisfy the requirements in ESD events. The characteristics of SITh for ESD protection were obtained using the Time Domain Reflectometer (TDR) type of Transmission Line Pulse (TLP) testing system. The results illustrate that SITh for ESD protection has the following advantages: 1) It has a strong ESD stress handing capability (3.75 kV); 2) Its second breakdown current is large enough (2.5 A) to release great ESD current; 3) DC leakage current of SITh is very small (1 μA); 4) SITh can break through the limitations of transitional trigger voltages, whose trigger voltage is dynamically adjustable as well; 5) The ESD response time can be controlled through optimizing device structure of SITh.

Abstract: In this paper, it gives a proposal for OCT/VT (optical current / voltage transformer) signals acquisition and processing. This project is used in smart grid, which needs high precision but low EMI. The OCT/VT use fiber to transform signals. It is insulating, susceptible to EMI, and there is no electromagnetic saturation phenomenon. Thus it can fulfill the requirement of smart grid. The project contains four parts: PD and amplification, ADC sampling, digital signals processing and storage, data transmission from PCB board to computer via USB. Compared with other similar methods, this system can provide faster processing speed and higher accuracy. The system measuring range is 0-1000A (OCT) after shunt, and 0-1000V (OVT) after divider, both meet the 0.2S industry standard.

Abstract: Studied the OVERHAUSER magnetometer signal's production mechanism and instrument's working principle, designed high frequency energizer, DC polarization circuit and signal detecting circuit. Detecting circuit was composed of the analog frequency selective amplification, narrow-band filter, programmable amplifier and controller. In setting conditions, the probe output Larmor precession signal, then collected the signal by the detecting circuit. The results show the single identified with the theoretical analysis with a higher SNR. Provided an important basis for the increase of the system sampling rate by analysising the relationship between the poling time and the output signals amplitude.

Abstract: In this paper, a passive UHF reader design with cryptographic technique SM2 is presented. By designing board compatibility of security module, RFID control module, RF module, communications interface, the passive UHF reader can both operate at common mode and security mode. This design constructs a suitable candidate for reliability, integrity, security of information transmission of RFID application in special field of internet of things.

Abstract: In this paper, an inverted F antenna works in the 5.8GHz frequency band is proposed. On the platform of Ansoft HFSS14 , the antenna’s return loss reaches -51.97dB at the center frequency 5.8GHz and the relative bandwidth is about 22.4％ when the return loss is less than -10dB. Also ,the size of the antenna is only 18mm*15mm. Compared with the existing antenna works in the same frequency band , the inverted F antenna proposed has a lower return loss and smaller physical size. The new designed antenna can be applied to the RFID system of road tolls and container management, which have certain values for application.

Abstract: A miniaturized microstrip Wilkinson power divider is proposed in this paper. The designed power divider is miniaturized by means of using the snake-shaped structure to meet the engineering requirements. During the operation frequency band, the designed Wilkinson power divider has good performance of impedance matching at three ports and the measured return loss of each port are all less than -17dB. The isolation between two output ports is better than -20dB. The insert loss is less than 0.7dB. The designed power divider is fabricated to validate the design. The proposed power divider is measured and the simulated and measured results have a good agreement.

Abstract: In this paper, a Gaussian Pulse Generator for use in CMOS UWB transmitters and use in the wireless inter or intra chip communication. The proposed architecture is composed of a simple and robust design of a Gaussian Monocycle impulse generator at the transmitter, a wideband short-range on-chip transformer for data transmission. The circuit was implemented and simulated in ADS2009 using 0.25μm CMOS technology with a supply voltage of 3.3V. Ultra-short GMP signals of 25ps duration and 40GHz center frequency.