A 2.4GHz ASK transmitter suitable for a low power wireless capsule endoscope system is presented. A mixer-based frequency up-conversion transmitter architecture is employed to achieve a high data rate. A pseudodiffere...A 2.4GHz ASK transmitter suitable for a low power wireless capsule endoscope system is presented. A mixer-based frequency up-conversion transmitter architecture is employed to achieve a high data rate. A pseudodifferential stacked class-A power amplifier using the current reuse technique is proposed to save power. The transmitter mainly includes two parts： a 20MHz ASK modulator based on a constant amplitude phase lock loop （PLL） and a direct up-conversion RF circuit. This design, implemented in a TSMC 0.25μm CMOS process, achieves a - 23. 217dBm output power with a data rate of 1Mbps and dissipates 3.17mA of current with a single 2.5V power supply.展开更多
By taking the surface chemical reactions as the rate-controlling step, a possible reaction mechanism for ethylene epoxidation to synthesize ethylene oxide over the A-type silver catalyst was developed, while it was as...By taking the surface chemical reactions as the rate-controlling step, a possible reaction mechanism for ethylene epoxidation to synthesize ethylene oxide over the A-type silver catalyst was developed, while it was assumed that the epoxidation reaction would take place between ethylene and the un-dissociated adsorbed oxygen O2 a on the solo active sites, while the deep oxidation would occur between ethylene and the dissociated adsorbed oxygen Oa on the adjacent multi-active sites. In order to describe the effect of 1,2-C2H4Cl2(EDC) inhibitor on the ethylene epoxidation process, the reversible reactions between EDC and vinyl chloride(VC) on the active sites of silver catalyst was introduced. According to the assumed mechanism, the hyperbolic macro-kinetic model of ethylene epoxidation over the A-type silver catalyst was established, and the macrokinetic experiments were carried out in an internal-recycle gradientless reactor operating at a pressure of 2.1 MPa and a temperature in the range of 217.8—249.0 ℃, with the gas composition(molar fraction) consisting of 15.82%—34.65% C2H4, 2.55%—7.80% O2, 0.88%—6.15% CO2, 0.15—2.61 μmol/mol of 1,2-C2H4Cl2 and 0.14—1.28 μmol/mol of C2H3 Cl. By means of the Simplex Optimal Method, the parameters of the macrokinetic models were estimated. Statistical test showed that the macrokinetic models developed for the A-type silver catalyst agree well with the experimental results.展开更多
In this paper, an indoor environmental monitoring solution is proposed for the transformer sub- station system by using the ZigBee technology. It mainly analyzes the principle of sulfur hexafluoride sensor based on th...In this paper, an indoor environmental monitoring solution is proposed for the transformer sub- station system by using the ZigBee technology. It mainly analyzes the principle of sulfur hexafluoride sensor based on the acoustic method and puts forward a difference data processing method of single- channel and temperature compensation point at power consumption issues for sensor detection. The method not only reduces the sensor power consumption, but also ensures the accuracy and extends the lifetime of wireless sensor nodes effectively. This paper also analyzes the design of the base sta- tion mode, and demonstrates the running processes of routers and sensors. The feasibility of the pro- posed approach has been testified and proved.展开更多
During the course of the last years the need for the increase in the electric energy production in Brazil as well as in the rest of the world, has raised the tone of the debate about the environment impact of such pro...During the course of the last years the need for the increase in the electric energy production in Brazil as well as in the rest of the world, has raised the tone of the debate about the environment impact of such production. As a result of these debates, both the several levels of government and some of the NGOs （Non-Governmental Organizations） have commissioned innumerous opinion researches aiming at measuring and evaluating the knowledge and perception of the public in relation of the best non-polluting energy sources. Prior to 2001 these researches would not make any sense in Brazil., however due to that year＇s drought, the competent authorities were faced with the necessity of developing a plan, the PNE2030 （Piano Nacional de Energia） aiming, among others objectives, at finalizing the construction of the Angra three plants and implementing new nuclear plants in places still to be determined. Allowing for the complexity of the subject, this paper presents a field research conducted from September 28th, 2010 to October 28th, 2010 assessing the current level of perception of the Brazilian population about the nuclear area, in particular of the residents of three cities of Rio de Janeiro. As a result of this work, the authors suggest how the competent authorities should proceed to reach in an efficient manner a greater understanding of the population about the proposed subject, through communication campaigns being both informative and educational.展开更多
文摘A 2.4GHz ASK transmitter suitable for a low power wireless capsule endoscope system is presented. A mixer-based frequency up-conversion transmitter architecture is employed to achieve a high data rate. A pseudodifferential stacked class-A power amplifier using the current reuse technique is proposed to save power. The transmitter mainly includes two parts： a 20MHz ASK modulator based on a constant amplitude phase lock loop （PLL） and a direct up-conversion RF circuit. This design, implemented in a TSMC 0.25μm CMOS process, achieves a - 23. 217dBm output power with a data rate of 1Mbps and dissipates 3.17mA of current with a single 2.5V power supply.
文摘By taking the surface chemical reactions as the rate-controlling step, a possible reaction mechanism for ethylene epoxidation to synthesize ethylene oxide over the A-type silver catalyst was developed, while it was assumed that the epoxidation reaction would take place between ethylene and the un-dissociated adsorbed oxygen O2 a on the solo active sites, while the deep oxidation would occur between ethylene and the dissociated adsorbed oxygen Oa on the adjacent multi-active sites. In order to describe the effect of 1,2-C2H4Cl2(EDC) inhibitor on the ethylene epoxidation process, the reversible reactions between EDC and vinyl chloride(VC) on the active sites of silver catalyst was introduced. According to the assumed mechanism, the hyperbolic macro-kinetic model of ethylene epoxidation over the A-type silver catalyst was established, and the macrokinetic experiments were carried out in an internal-recycle gradientless reactor operating at a pressure of 2.1 MPa and a temperature in the range of 217.8—249.0 ℃, with the gas composition(molar fraction) consisting of 15.82%—34.65% C2H4, 2.55%—7.80% O2, 0.88%—6.15% CO2, 0.15—2.61 μmol/mol of 1,2-C2H4Cl2 and 0.14—1.28 μmol/mol of C2H3 Cl. By means of the Simplex Optimal Method, the parameters of the macrokinetic models were estimated. Statistical test showed that the macrokinetic models developed for the A-type silver catalyst agree well with the experimental results.
基金Supported by the National Natural Science Foundation of China （ No. 10974044）, the Fundamental Research Funds for the Central Universities of Hohai University （No. 2009B31514） and the 2009 Jiangsu Province Graduate Education Reform and Practical Project （No. 2009-22）.
文摘In this paper, an indoor environmental monitoring solution is proposed for the transformer sub- station system by using the ZigBee technology. It mainly analyzes the principle of sulfur hexafluoride sensor based on the acoustic method and puts forward a difference data processing method of single- channel and temperature compensation point at power consumption issues for sensor detection. The method not only reduces the sensor power consumption, but also ensures the accuracy and extends the lifetime of wireless sensor nodes effectively. This paper also analyzes the design of the base sta- tion mode, and demonstrates the running processes of routers and sensors. The feasibility of the pro- posed approach has been testified and proved.
文摘During the course of the last years the need for the increase in the electric energy production in Brazil as well as in the rest of the world, has raised the tone of the debate about the environment impact of such production. As a result of these debates, both the several levels of government and some of the NGOs （Non-Governmental Organizations） have commissioned innumerous opinion researches aiming at measuring and evaluating the knowledge and perception of the public in relation of the best non-polluting energy sources. Prior to 2001 these researches would not make any sense in Brazil., however due to that year＇s drought, the competent authorities were faced with the necessity of developing a plan, the PNE2030 （Piano Nacional de Energia） aiming, among others objectives, at finalizing the construction of the Angra three plants and implementing new nuclear plants in places still to be determined. Allowing for the complexity of the subject, this paper presents a field research conducted from September 28th, 2010 to October 28th, 2010 assessing the current level of perception of the Brazilian population about the nuclear area, in particular of the residents of three cities of Rio de Janeiro. As a result of this work, the authors suggest how the competent authorities should proceed to reach in an efficient manner a greater understanding of the population about the proposed subject, through communication campaigns being both informative and educational.
