317 publications from this institution
The use of sea sand in engineering construction is an effective solution to solve the problem of shortage of building sand in the coastal area not only,and is also reduces environmental impact. Upon review of the existing reinforced sea sand concrete applications,it is clear that there have been many substandard outcomes,primarily due to steel corrosion. Although these problems can be largely avoided by thoroughly washing sea sands with fresh water,the process is extremely water intensive,meaning that its overall usefulness is limited. However,fiber reinforced polymer( FRP) materials have both excellent mechanical performance and resistance to chloride-induced corrosion. Using FRP reinforcement and sea sand concrete in concert can avoid corrosion problems entirely. There are already many potential applications for this type of composite structure,and the prospects of further future development are equally good. An innovative FRP-concrete hybrid structural system for use in seaborne engineering is proposed herein. Specifically,this structure aims to fulfill an increasing demand for seaborne and coastal development. Meanwhile,it is also hoped to promote the application of sea sand concrete and FRP in engineering structures.
This paper proposes a sigma-delta fractional-N frequency synthesizer-based multi-standard I/Q carrier generation system.With reasonable frequency planning,the system can be used in multi-standard wireless communication applications(GSM,WCDMA,GPRS,TD-SCDMA,WLAN(802.11a/b/g)).The implementation is achieved by a 0.13μm RF CMOS process.The measured results demonstrate that three quadrature VCOs(QVCO) continuously cover the frequency from 3.1 to 6.1 GHz(65.2%),and through the successive divide-by-2 prescalers to achieve the frequency from 0.75 to 6.1 GHz continuously.The chip was fully integrated with the exception of an off-chip filter.The entire chip area is only 3.78 mm~2,and the system consumes a 21.7 mA@1.2 V supply without output buffers.The lock-in time of the PLL frequency synthesizer is less than 4μs over the entire frequency range with a direct frequency presetting technique and the auxiliary non-volatile memory(NVM)can store the digital configuration signal of the system,including presetting signals to avoid the calibration process case by case.
