Aiming at localizing the telemetric capsule for detecting gastrointestinal physiological parameters in vivo accurately,a portable alternating current(AC)electromagnetic localization system is designed.To verify the fe...Aiming at localizing the telemetric capsule for detecting gastrointestinal physiological parameters in vivo accurately,a portable alternating current(AC)electromagnetic localization system is designed.To verify the feasibility of the method,the model and construction of the localization system are detailed.And static and dynamic accuracy of the localization system are tested by experiments.Next,we compare the simulating results of the electromagnetic radiation aroused by the localization system with the electromagnetic safety standards of human(ICNIRP guidelines and IEEE standard C95.1-1991).Finally,in terms of the results of the static and dynamic experiments,conclusions are drawn that the accuracy of portable positioning system is high(less than 10 mm)enough to satisfy the localization need of the micro invasive medical devices in vivo,and there is no harm of electromagnetic radiation to human.展开更多
This paper describes a CMOS low noise amplifier （LNA） plus the quadrature mixers intended for use in the front-end of portable global positioning system （GPS） receivers. The LNA makes use of an inductively degener...This paper describes a CMOS low noise amplifier （LNA） plus the quadrature mixers intended for use in the front-end of portable global positioning system （GPS） receivers. The LNA makes use of an inductively degenerated input stage and power-constrained simultaneous noise and input matching techniques. The quadrature mixers are based on a Gil- bert cell type. The circuits are implemented in a TSMC 0.18μm RF CMOS process. Measurement results show that a voltage conversion gain of 35dB is achieved with a cascade noise and an input return loss of - 22.3dB. The fully differential figure of 2.4dB,an input ldB compression point of - 22dBm, circuits only draw 5.4mW from a 1.8V supply.展开更多
Heterogeneous catalytic reactions involve the use of highly dispersed active phases such as metal, metal oxide, or metal sulphide nanoparticIes on thermally stable supports. Fluctuations of the reaction temperature du...Heterogeneous catalytic reactions involve the use of highly dispersed active phases such as metal, metal oxide, or metal sulphide nanoparticIes on thermally stable supports. Fluctuations of the reaction temperature during the reactions can induce sintering of the particles. The stability of such small particles represents a crucial parameter in the development of new families of catalysts with high activity in many fields. Here we report the stability of platinum nanoparticles （2-3 nm） on a few-layer graphene （FLG） surface as studied by in situ high temperature transmission electron microscopy.展开更多
基金National Natural Science Foundation of China(NSFC)(No.30570485)National High Technology Research and Development Program of China(863)(No.2006AA04Z368)Natural Science Foundation of Shanghai,China(No.06ER1406)
文摘Aiming at localizing the telemetric capsule for detecting gastrointestinal physiological parameters in vivo accurately,a portable alternating current(AC)electromagnetic localization system is designed.To verify the feasibility of the method,the model and construction of the localization system are detailed.And static and dynamic accuracy of the localization system are tested by experiments.Next,we compare the simulating results of the electromagnetic radiation aroused by the localization system with the electromagnetic safety standards of human(ICNIRP guidelines and IEEE standard C95.1-1991).Finally,in terms of the results of the static and dynamic experiments,conclusions are drawn that the accuracy of portable positioning system is high(less than 10 mm)enough to satisfy the localization need of the micro invasive medical devices in vivo,and there is no harm of electromagnetic radiation to human.
文摘This paper describes a CMOS low noise amplifier （LNA） plus the quadrature mixers intended for use in the front-end of portable global positioning system （GPS） receivers. The LNA makes use of an inductively degenerated input stage and power-constrained simultaneous noise and input matching techniques. The quadrature mixers are based on a Gil- bert cell type. The circuits are implemented in a TSMC 0.18μm RF CMOS process. Measurement results show that a voltage conversion gain of 35dB is achieved with a cascade noise and an input return loss of - 22.3dB. The fully differential figure of 2.4dB,an input ldB compression point of - 22dBm, circuits only draw 5.4mW from a 1.8V supply.
文摘Heterogeneous catalytic reactions involve the use of highly dispersed active phases such as metal, metal oxide, or metal sulphide nanoparticIes on thermally stable supports. Fluctuations of the reaction temperature during the reactions can induce sintering of the particles. The stability of such small particles represents a crucial parameter in the development of new families of catalysts with high activity in many fields. Here we report the stability of platinum nanoparticles （2-3 nm） on a few-layer graphene （FLG） surface as studied by in situ high temperature transmission electron microscopy.
