The nanocrystalline Ho3+/Tm3+/Yb3+ co-doped CaWO4 upconversion(UC) phosphors were successfully synthesized by a modified citrate complex method using microwave irradiation. The citrate complex precursors were heat-tre...The nanocrystalline Ho3+/Tm3+/Yb3+ co-doped CaWO4 upconversion(UC) phosphors were successfully synthesized by a modified citrate complex method using microwave irradiation. The citrate complex precursors were heat-treated at temperature ranging from 300 to 700 °C for 3 h. Crystallization of the Ho3+/Tm3+/Yb3+ co-doped CaWO4 was detected at 400 °C, and entirely completed at 600 °C. The Ho3+/Tm3+/Yb3+ co-doped CaWO4 heat-treated at 600 °C showed primarily spherical and homogeneous morphology. Under the laser excitation of 980 nm, Ho3+/Tm3+/Yb3+ co-doped CaWO4 shows the bright white upconversion(UC) emission visible to the naked eye, which is composed of a blue emission at 475 nm from Tm3+, and green and red emissions at 543 and 651 nm respectively from Ho3+. The coordinates of Ho3+/Tm3+/Yb3+ co-doped CaWO4 in the Commission International De'eclairage(CIE) chromaticity diagram could be controlled from a cool to a warm white color depending on the Tm3+ and Ho3+ concentrations. The UC luminescent properties on Tm3+ and Ho3+ concentrations and related mechanism based on laser pump power were discussed in detail.展开更多
This paper presents an RF energy harvesting system for wireless intraocular pressure monitoring applications.The system consists of an implantable antenna and a rectifier.A new sizing strategy is adopted to optimize t...This paper presents an RF energy harvesting system for wireless intraocular pressure monitoring applications.The system consists of an implantable antenna and a rectifier.A new sizing strategy is adopted to optimize the conversion efficiency of the rectifier,and the design principle of an implantable antenna is introduced from material selection and structure design.Results from testing demonstrate that the antenna gain is about-20 dBi and the rectifier's maximum total conversion efficiency which contains match efficiency and rectifying efficiency is 47.18%under the implementation of0.18μm standard CMOS process.The maximum power obtained from the proposed system is 8μW when the power density of electromagnetic wave is lower than the national standard 40μW/cm^2 at915 MHz,which is enough to power the intraocular pressure monitoring system.展开更多
The paper presents a framework for developing a variety of video transition effects. The framework is designed to deal with the problem of inefficiency for programmers to generate more and more diversified video trans...The paper presents a framework for developing a variety of video transition effects. The framework is designed to deal with the problem of inefficiency for programmers to generate more and more diversified video transition, which is caused by excessive coupling between the sub-modules of the system. So the framework is designed to be modular, flexible and extensible. Based on the analysis of common features of different effects, the implementation of video transition effect is divided into 4 sub-odules, each of which can be designed and developed independently. Furthermore, these sub-modules can be easily sub- stituted, modified and reused. We present a formal description of our framework, and give typical study cases to show the extensive utility of the framework.展开更多
We propose a dual band CMOS power amplifier for mobile WiMAX systems. The power amplifier,combined with an active matching transformer,is fully integrated and fabricated in a 0.13μm CMOS process. The transformer oper...We propose a dual band CMOS power amplifier for mobile WiMAX systems. The power amplifier,combined with an active matching transformer,is fully integrated and fabricated in a 0.13μm CMOS process. The transformer operates at dual bands with active matching circuit. The measured result shows that the transformer efficiency of 78.2% and 70.4% at 2.5 and 3.5GHz are realized,respectively,and 26.5 and 24. 8dB gain are achieved. The PAE reaches 20% and 28% at 2.5 and 3.5GHz, respectively. The third inter-modulation （IM3） is lower than - 30dBc at the 25dBm average power.展开更多
基金supported by a grant from the LINC (Leaders in INdustry-university Cooperation) Program of Korea National University of Transportation in 2013
文摘The nanocrystalline Ho3+/Tm3+/Yb3+ co-doped CaWO4 upconversion(UC) phosphors were successfully synthesized by a modified citrate complex method using microwave irradiation. The citrate complex precursors were heat-treated at temperature ranging from 300 to 700 °C for 3 h. Crystallization of the Ho3+/Tm3+/Yb3+ co-doped CaWO4 was detected at 400 °C, and entirely completed at 600 °C. The Ho3+/Tm3+/Yb3+ co-doped CaWO4 heat-treated at 600 °C showed primarily spherical and homogeneous morphology. Under the laser excitation of 980 nm, Ho3+/Tm3+/Yb3+ co-doped CaWO4 shows the bright white upconversion(UC) emission visible to the naked eye, which is composed of a blue emission at 475 nm from Tm3+, and green and red emissions at 543 and 651 nm respectively from Ho3+. The coordinates of Ho3+/Tm3+/Yb3+ co-doped CaWO4 in the Commission International De'eclairage(CIE) chromaticity diagram could be controlled from a cool to a warm white color depending on the Tm3+ and Ho3+ concentrations. The UC luminescent properties on Tm3+ and Ho3+ concentrations and related mechanism based on laser pump power were discussed in detail.
基金Supported by the Shanghai Science Committee Project(No.Y232821D01)
文摘This paper presents an RF energy harvesting system for wireless intraocular pressure monitoring applications.The system consists of an implantable antenna and a rectifier.A new sizing strategy is adopted to optimize the conversion efficiency of the rectifier,and the design principle of an implantable antenna is introduced from material selection and structure design.Results from testing demonstrate that the antenna gain is about-20 dBi and the rectifier's maximum total conversion efficiency which contains match efficiency and rectifying efficiency is 47.18%under the implementation of0.18μm standard CMOS process.The maximum power obtained from the proposed system is 8μW when the power density of electromagnetic wave is lower than the national standard 40μW/cm^2 at915 MHz,which is enough to power the intraocular pressure monitoring system.
文摘The paper presents a framework for developing a variety of video transition effects. The framework is designed to deal with the problem of inefficiency for programmers to generate more and more diversified video transition, which is caused by excessive coupling between the sub-modules of the system. So the framework is designed to be modular, flexible and extensible. Based on the analysis of common features of different effects, the implementation of video transition effect is divided into 4 sub-odules, each of which can be designed and developed independently. Furthermore, these sub-modules can be easily sub- stituted, modified and reused. We present a formal description of our framework, and give typical study cases to show the extensive utility of the framework.
基金the Research Fund for the Doctoral Program of Higher Education of China~~
文摘We propose a dual band CMOS power amplifier for mobile WiMAX systems. The power amplifier,combined with an active matching transformer,is fully integrated and fabricated in a 0.13μm CMOS process. The transformer operates at dual bands with active matching circuit. The measured result shows that the transformer efficiency of 78.2% and 70.4% at 2.5 and 3.5GHz are realized,respectively,and 26.5 and 24. 8dB gain are achieved. The PAE reaches 20% and 28% at 2.5 and 3.5GHz, respectively. The third inter-modulation （IM3） is lower than - 30dBc at the 25dBm average power.
