A micromachined vertical cavity tunable filter with AlGaAs/GaAs distributed Bragg reflector is presented.This filter can be electrostatic tuning over a range of 28nm with an applied voltage of 7V.
This paper presents a high precision CMOS opamp suitable for ISFET readout. The opamp is tailored to provide a constant bias condition for ISFET as part of the readout circuits and,hence,is compatible for single chip ...This paper presents a high precision CMOS opamp suitable for ISFET readout. The opamp is tailored to provide a constant bias condition for ISFET as part of the readout circuits and,hence,is compatible for single chip integration with the sensor. A continuous time auto-zero stabilization technique is studied and employed, with the aim of suppressing the low frequency noises, including the offset voltage, 1/f noise, and temperature drift. The design is based on a 0.35μm CMOS process. With a 3.3V power supply,it maintains a DC open loop gain of more than 100dB and an offset voltage of around 11μV,while the overall power dissipation is only 1.48mW. With this opamp, a pH microsensor is constructed, of which the functionality is verified by experimental tests.展开更多
Optical filters capable of single control parameter based wide tuning are implemented and studied.A prototype surface micromachined 1 3μm Si based MOEMS (micro opto electro mechanical systems) tunable filter e...Optical filters capable of single control parameter based wide tuning are implemented and studied.A prototype surface micromachined 1 3μm Si based MOEMS (micro opto electro mechanical systems) tunable filter exhibits a continuous and large tuning range of 90nm at 50V tuning voltage.The filter can be integrated with Si based photodetector in a low cost component for coarse wavelength division multiplexing systems operating in the 1 3μm band.展开更多
Multi-function,multiband,cost-effective,miniaturized reconfigurable radio frequency(RF)components are highly demanded in modern and future wireless communication systems.This paper discusses the needs and implementati...Multi-function,multiband,cost-effective,miniaturized reconfigurable radio frequency(RF)components are highly demanded in modern and future wireless communication systems.This paper discusses the needs and implementation of multiband reconfigurable RF components with microfabrication techniques and advanced materials.RF applications of fabrication methods such as surface and bulk micromachining techniques are reviewed,especially on the development of RF microelectromechanical systems(MEMS)and other tunable components.Works on the application of ferroelectric and ferromagnetic materials are investigated,which enables RF components with continuous tunability,reduced size,and enhanced performance.Methods and strategies with nano-patterning to improve high frequency characteristics of ferromagnetic thin film(e.g.,ferromagnetic resonance frequency and losses)and their applications on the development of fully electrically tunable RF components are fully demonstrated.展开更多
In the article, the author presents some arguments concerning the ＂mathematical method issue＂ in modem economics. The author shows why some reasons, according to which we should use mathematics in （economic） theor...In the article, the author presents some arguments concerning the ＂mathematical method issue＂ in modem economics. The author shows why some reasons, according to which we should use mathematics in （economic） theory, are not convincing （they are even tautological）, and what does mathematization have to do with arbitrariness of the orthodox economic theory. The author also shows why using game theory （a mathematical discipline） in modem microeconomics does not yield knowledge and correct explanation of economic situations and phenomena. At the end, the author presents fundamental questions that form the basis of economic science and its qualitative research methods, and shows what their practical relevance is. The purpose of this article is to argue, contrary to common opinion, that there can be an exact and objective science of economic phenomena that does not necessarily use modem mathematical theories or methods to explain these phenomena.展开更多
Based on polymer microstructured optical fibers (PMOF) and selective liquid crystal injection technology, a novel tem- perature control tunable attenuator is designed theoretically in this paper. In our experiments, P...Based on polymer microstructured optical fibers (PMOF) and selective liquid crystal injection technology, a novel tem- perature control tunable attenuator is designed theoretically in this paper. In our experiments, PMMA microstructured optical fibers with high performance are drawn successfully and the selective injection of liquid crystal 5CB into micro- holes is realized. The tunable attenuator is fabricated with an extinction ratio of over 60dB, which agrees well with the design.展开更多
A new type of compact terahertz (THz) radiation source using free electron laser (FEL) is discussed in this paper.The concept machine consists of an independently tunable cell thermionic RF gun (ITC-RF Gun),an acceler...A new type of compact terahertz (THz) radiation source using free electron laser (FEL) is discussed in this paper.The concept machine consists of an independently tunable cell thermionic RF gun (ITC-RF Gun),an accelerating structure with symmetry RF-incoupler and a coaxial load RF-outcoupler,an undulator combined with an optical resonance cavity of hole-coupling mode.Withoutα-magnet and other bunch compressors,the size of this machine is decreased.The conceptual design and numerical simulation are presented.展开更多
文摘A micromachined vertical cavity tunable filter with AlGaAs/GaAs distributed Bragg reflector is presented.This filter can be electrostatic tuning over a range of 28nm with an applied voltage of 7V.
文摘This paper presents a high precision CMOS opamp suitable for ISFET readout. The opamp is tailored to provide a constant bias condition for ISFET as part of the readout circuits and,hence,is compatible for single chip integration with the sensor. A continuous time auto-zero stabilization technique is studied and employed, with the aim of suppressing the low frequency noises, including the offset voltage, 1/f noise, and temperature drift. The design is based on a 0.35μm CMOS process. With a 3.3V power supply,it maintains a DC open loop gain of more than 100dB and an offset voltage of around 11μV,while the overall power dissipation is only 1.48mW. With this opamp, a pH microsensor is constructed, of which the functionality is verified by experimental tests.
文摘Optical filters capable of single control parameter based wide tuning are implemented and studied.A prototype surface micromachined 1 3μm Si based MOEMS (micro opto electro mechanical systems) tunable filter exhibits a continuous and large tuning range of 90nm at 50V tuning voltage.The filter can be integrated with Si based photodetector in a low cost component for coarse wavelength division multiplexing systems operating in the 1 3μm band.
基金Projects(1253929,1910853)supported by the National Natural Science Foundation of China。
文摘Multi-function,multiband,cost-effective,miniaturized reconfigurable radio frequency(RF)components are highly demanded in modern and future wireless communication systems.This paper discusses the needs and implementation of multiband reconfigurable RF components with microfabrication techniques and advanced materials.RF applications of fabrication methods such as surface and bulk micromachining techniques are reviewed,especially on the development of RF microelectromechanical systems(MEMS)and other tunable components.Works on the application of ferroelectric and ferromagnetic materials are investigated,which enables RF components with continuous tunability,reduced size,and enhanced performance.Methods and strategies with nano-patterning to improve high frequency characteristics of ferromagnetic thin film(e.g.,ferromagnetic resonance frequency and losses)and their applications on the development of fully electrically tunable RF components are fully demonstrated.
文摘In the article, the author presents some arguments concerning the ＂mathematical method issue＂ in modem economics. The author shows why some reasons, according to which we should use mathematics in （economic） theory, are not convincing （they are even tautological）, and what does mathematization have to do with arbitrariness of the orthodox economic theory. The author also shows why using game theory （a mathematical discipline） in modem microeconomics does not yield knowledge and correct explanation of economic situations and phenomena. At the end, the author presents fundamental questions that form the basis of economic science and its qualitative research methods, and shows what their practical relevance is. The purpose of this article is to argue, contrary to common opinion, that there can be an exact and objective science of economic phenomena that does not necessarily use modem mathematical theories or methods to explain these phenomena.
基金the National Basic Research Program ofChina (973 Program) (2003CB314907), Tsinghua National Labo-ratory for Information Science and Technology (TNList), and Na-tional Natural Science Foundation of China.
文摘Based on polymer microstructured optical fibers (PMOF) and selective liquid crystal injection technology, a novel tem- perature control tunable attenuator is designed theoretically in this paper. In our experiments, PMMA microstructured optical fibers with high performance are drawn successfully and the selective injection of liquid crystal 5CB into micro- holes is realized. The tunable attenuator is fabricated with an extinction ratio of over 60dB, which agrees well with the design.
文摘A new type of compact terahertz (THz) radiation source using free electron laser (FEL) is discussed in this paper.The concept machine consists of an independently tunable cell thermionic RF gun (ITC-RF Gun),an accelerating structure with symmetry RF-incoupler and a coaxial load RF-outcoupler,an undulator combined with an optical resonance cavity of hole-coupling mode.Withoutα-magnet and other bunch compressors,the size of this machine is decreased.The conceptual design and numerical simulation are presented.
