A voltage controlled oscillator (VCO) which can generate 2 4GHz quadrature local oscillating (LO) signals is reported.It combines a LC VCO,realized by on chip symmetrical spiral inductors and differential diodes,an...A voltage controlled oscillator (VCO) which can generate 2 4GHz quadrature local oscillating (LO) signals is reported.It combines a LC VCO,realized by on chip symmetrical spiral inductors and differential diodes,and a two stage ring VCO.The principle of this VCO is demonstrated and further the phase noise is discussed in detail.The fabrication of prototype is demonstrated using 0 25μm single poly five metal N well salicide CMOS digital process.The reports show that the novel VCO is can generate quadrature LO signals with a tuning range of more than 300MHz as well as the phase noise--104 33dBc/Hz at 600KHz offset at 2 41GHz (when measuring only one port of differential outputs).In addition,this VCO can work in low power supply voltage and dissipate low power,thus it can be used in many integrated transceivers.展开更多
On-line Cu （II） ion concentration detection in bioleaching system was achieved by anodic stripping differential pulse voltammetry （ASDPV）. Good linearity between Cu （II） concentration and oxidation peak current ...On-line Cu （II） ion concentration detection in bioleaching system was achieved by anodic stripping differential pulse voltammetry （ASDPV）. Good linearity between Cu （II） concentration and oxidation peak current was obtained when Cu （II） existed in 0K media in the concentration range of 1μmol/L （64μg/L） to 1 mmol/L （64 mg/L）. Moreover, when 0.2 mol/L KCl was added into this media, the linear detection range could be extended from 1 mmol/L to 100 mmol/L （6.4 g/L）. The reduction of Cu （II） to metallic copper was shown to proceed as two successive single-electron transfer reactions involving an intermediate chemical step where the cuprous ion （Cu＋） was complexed by chloride to form the dichlorocuprous anion （CuCl-）. In addition, interference effect was also investigated when Fe3＋existed in the media, which was the common situation in the copper bioleaching system. The results showed no interference effect once the concentration of Fe3＋was less than 100 mmol/L （5.6 g/L）.展开更多
This paper discusses the calculation of the trapping forces in optical tweezers using a combination of the finite differences time domain （FDTD） method and the Lorentz force on electric dipoles. The results of 2D si...This paper discusses the calculation of the trapping forces in optical tweezers using a combination of the finite differences time domain （FDTD） method and the Lorentz force on electric dipoles. The results of 2D simulations of the trapping of a circular particle by a waveguide with a circular tip are presented and discussed.展开更多
Screen printing is a promising technology because of its simplicity, low-cost, high reproducibility, and efficiency in large-scale production. In this work, a cobalt-based phosphate sensor was successfully fabricated ...Screen printing is a promising technology because of its simplicity, low-cost, high reproducibility, and efficiency in large-scale production. In this work, a cobalt-based phosphate sensor was successfully fabricated using the screen printing technology for the determination of phosphate concentration in the aqueous solution. The disposable sensor consists of a fully integrated cobalt （Co） electrode, which is a layer of carbon conductive ink （C） physically doped with Co powder, and Ag/AgCI reference electrode. The SEM images show that the morphology of the Co electrode changes after exposure to the phosphate solution, indicating that the expendable reaction exists during the measurement. At the Co/C ratio of 1：99, the cobalt-based phosphate sensor shows phosphate-selective potential response in the range of 10-4 to 10-1 mol/L, yielding a detection limit of lxl0-5 mol/L and a slope of over 30 mV/decade in acidic solution （pH 4.5） for HzPO4-. The proposed screen-printed sensor also ex- hibited significant reproducibility with a small repeated sensing deviation （i.e., relative standard deviation （R.S.D.） of 0.5%） on a single sensor and a small electrode-to-electrode deviation （i.e., R.S.D. 〈 3.2%）. The recovery study of HzPO4- in real wastewater samples gave values from 95.4% to 101.8%, confirming its application potential in the measurement of phosphate in real samples. Apart from its high selectivity, sensitivity, and stability comparable with a conventional bulk Co-wire electrode, the proposed phosphate sensor still yields many other advantages, such as low price, compactness, ease of use, and the possibility of integration with other analytical devices such as flow injection analysis.展开更多
文摘A voltage controlled oscillator (VCO) which can generate 2 4GHz quadrature local oscillating (LO) signals is reported.It combines a LC VCO,realized by on chip symmetrical spiral inductors and differential diodes,and a two stage ring VCO.The principle of this VCO is demonstrated and further the phase noise is discussed in detail.The fabrication of prototype is demonstrated using 0 25μm single poly five metal N well salicide CMOS digital process.The reports show that the novel VCO is can generate quadrature LO signals with a tuning range of more than 300MHz as well as the phase noise--104 33dBc/Hz at 600KHz offset at 2 41GHz (when measuring only one port of differential outputs).In addition,this VCO can work in low power supply voltage and dissipate low power,thus it can be used in many integrated transceivers.
基金Projects(2012CB933303,2011CB707505)supported by the National Basic Research Program of ChinaProject(2012BAK08B05)supported by the National Key Technology R&D Program of China+1 种基金Projects(11391901900,11530700800,10391901600,201101042,11CH-15)supported by Science and Technology Commission of Shanghai Municipality,ChinaProject supported by Funding from CSIRO CEO Science Leader Program
文摘On-line Cu （II） ion concentration detection in bioleaching system was achieved by anodic stripping differential pulse voltammetry （ASDPV）. Good linearity between Cu （II） concentration and oxidation peak current was obtained when Cu （II） existed in 0K media in the concentration range of 1μmol/L （64μg/L） to 1 mmol/L （64 mg/L）. Moreover, when 0.2 mol/L KCl was added into this media, the linear detection range could be extended from 1 mmol/L to 100 mmol/L （6.4 g/L）. The reduction of Cu （II） to metallic copper was shown to proceed as two successive single-electron transfer reactions involving an intermediate chemical step where the cuprous ion （Cu＋） was complexed by chloride to form the dichlorocuprous anion （CuCl-）. In addition, interference effect was also investigated when Fe3＋existed in the media, which was the common situation in the copper bioleaching system. The results showed no interference effect once the concentration of Fe3＋was less than 100 mmol/L （5.6 g/L）.
文摘This paper discusses the calculation of the trapping forces in optical tweezers using a combination of the finite differences time domain （FDTD） method and the Lorentz force on electric dipoles. The results of 2D simulations of the trapping of a circular particle by a waveguide with a circular tip are presented and discussed.
基金supported by the Major Scientific Equipment Development Project of China(2012YQ030111)the Beijing Natural Science Foundation(8132032)
文摘Screen printing is a promising technology because of its simplicity, low-cost, high reproducibility, and efficiency in large-scale production. In this work, a cobalt-based phosphate sensor was successfully fabricated using the screen printing technology for the determination of phosphate concentration in the aqueous solution. The disposable sensor consists of a fully integrated cobalt （Co） electrode, which is a layer of carbon conductive ink （C） physically doped with Co powder, and Ag/AgCI reference electrode. The SEM images show that the morphology of the Co electrode changes after exposure to the phosphate solution, indicating that the expendable reaction exists during the measurement. At the Co/C ratio of 1：99, the cobalt-based phosphate sensor shows phosphate-selective potential response in the range of 10-4 to 10-1 mol/L, yielding a detection limit of lxl0-5 mol/L and a slope of over 30 mV/decade in acidic solution （pH 4.5） for HzPO4-. The proposed screen-printed sensor also ex- hibited significant reproducibility with a small repeated sensing deviation （i.e., relative standard deviation （R.S.D.） of 0.5%） on a single sensor and a small electrode-to-electrode deviation （i.e., R.S.D. 〈 3.2%）. The recovery study of HzPO4- in real wastewater samples gave values from 95.4% to 101.8%, confirming its application potential in the measurement of phosphate in real samples. Apart from its high selectivity, sensitivity, and stability comparable with a conventional bulk Co-wire electrode, the proposed phosphate sensor still yields many other advantages, such as low price, compactness, ease of use, and the possibility of integration with other analytical devices such as flow injection analysis.
