This paper presents a 12-channel,30Gb/s front-end amplifier realized in standard 0.18μm CMOS technology for parallel optlc-fiber receivers. In order to overcome the problem of inadequate bandwidth caused by the large...This paper presents a 12-channel,30Gb/s front-end amplifier realized in standard 0.18μm CMOS technology for parallel optlc-fiber receivers. In order to overcome the problem of inadequate bandwidth caused by the large parasitical capacitor of CMOS photo-detectors,a regulated-cascode structure and noise optimization are used in the design of the transimpedance amplifier. The experimental results indicate that, with a parasitical capacitance of 2pF,a single channel is able to work at bite rates of up to 2.5Gb/s,and a clear eye diagram is obtained with a 0. 8mVpp input. Furthermore, an isolation structure combined with a p^＋ guard.ring （PGR）, an n^＋ guard-ring （NGR）,and a deep-n-well （DNW） for parallel amplifier is also presented. Taking this combined structure, the crosstalk and the substrate noise coupling have been effectively reduced. Compared with the isolation of PGR or PGR ＋ NGR,the measured results show that the isolation degree of this structure is improved by 29.2 and 8. ldB at 1GHz,and by 8. 1 and 2. 5dB at 2GHz,respectively. With a 1.8V supply,each channel of the front-end amplifier consumes a DC power of 85mW,and the total power consumption of 12 channels is about 1W.展开更多
A rapid analysis method of piperazine ferulate tablets by optic-fiber sensing technology with UV-vis absorption spectrum was established. Qualitative and quantitative data were obtained and compared by maximum and min...A rapid analysis method of piperazine ferulate tablets by optic-fiber sensing technology with UV-vis absorption spectrum was established. Qualitative and quantitative data were obtained and compared by maximum and minimum wavelength, absorbance and contrast spectra. Similarity method was used to identify authenticity of drugs. The difference of contents measured by this method and UV determination method in China Pharmacopoeia showed no statistical significance (P40.05), while the similarity can be used as a parameter to identify the authenticity of drugs.展开更多
A non-local dislocation density based crystal plasticity model, which takes account of the microstrncture inhomogeneity, was used to investigate the micro-bending of metallic crystalline foils. In this model, both sta...A non-local dislocation density based crystal plasticity model, which takes account of the microstrncture inhomogeneity, was used to investigate the micro-bending of metallic crystalline foils. In this model, both statistically stored dislocations （SSDs） and geometrically necessary dislocations （GNDs） are taken as the internal state variables. The strain gradient hardening in micro-bending of single-grained metal foils was predicted by evolution of GNDs. The predicted results were compared with the micro-hardness distribution of the previous micro-bending experiments of CuZn37 a-brass foils with coarse grains and fine grains. Comparison of the simulated dislocation densities distribution of SSDs and GNDs with the experimental results shows that different micro-hardness distribution patterns of the coarse and fine grain foils can be attributed to the corresponding SSDs and GNDs distributions. The present model provides a physical insight into the deformation mechanism and dislocation densities evolution of the micro-bending process.展开更多
Micro-bending tests were performed to investigate effects of thickness and grain size on material behavior in sheet metal forming.The rolling brass C2680 foil was selected as the experimental material,and it was annea...Micro-bending tests were performed to investigate effects of thickness and grain size on material behavior in sheet metal forming.The rolling brass C2680 foil was selected as the experimental material,and it was annealed to eliminate the work-hardening and get different grain sizes.A device was specially designed for three-point bending with two load sensors.The results show that the bending force increases with increasing the punch displacement.With the foil of same thickness,a smaller punch radius leads to a larger bending force.When the grain size increases,the bending force becomes smaller.Size effects are observed obviously.These results have been analyzed by work-hardening,Hall-Petch equation and free surface effect.展开更多
文摘This paper presents a 12-channel,30Gb/s front-end amplifier realized in standard 0.18μm CMOS technology for parallel optlc-fiber receivers. In order to overcome the problem of inadequate bandwidth caused by the large parasitical capacitor of CMOS photo-detectors,a regulated-cascode structure and noise optimization are used in the design of the transimpedance amplifier. The experimental results indicate that, with a parasitical capacitance of 2pF,a single channel is able to work at bite rates of up to 2.5Gb/s,and a clear eye diagram is obtained with a 0. 8mVpp input. Furthermore, an isolation structure combined with a p^＋ guard.ring （PGR）, an n^＋ guard-ring （NGR）,and a deep-n-well （DNW） for parallel amplifier is also presented. Taking this combined structure, the crosstalk and the substrate noise coupling have been effectively reduced. Compared with the isolation of PGR or PGR ＋ NGR,the measured results show that the isolation degree of this structure is improved by 29.2 and 8. ldB at 1GHz,and by 8. 1 and 2. 5dB at 2GHz,respectively. With a 1.8V supply,each channel of the front-end amplifier consumes a DC power of 85mW,and the total power consumption of 12 channels is about 1W.
文摘A rapid analysis method of piperazine ferulate tablets by optic-fiber sensing technology with UV-vis absorption spectrum was established. Qualitative and quantitative data were obtained and compared by maximum and minimum wavelength, absorbance and contrast spectra. Similarity method was used to identify authenticity of drugs. The difference of contents measured by this method and UV determination method in China Pharmacopoeia showed no statistical significance (P40.05), while the similarity can be used as a parameter to identify the authenticity of drugs.
基金Projects(50835002,50821003,50975174,51275297)supported by the National Natural Science Foundation of ChinaProjects(200802480053,20100073110044)supported by the PhD Programs Foundation of Ministry of Education of China
文摘A non-local dislocation density based crystal plasticity model, which takes account of the microstrncture inhomogeneity, was used to investigate the micro-bending of metallic crystalline foils. In this model, both statistically stored dislocations （SSDs） and geometrically necessary dislocations （GNDs） are taken as the internal state variables. The strain gradient hardening in micro-bending of single-grained metal foils was predicted by evolution of GNDs. The predicted results were compared with the micro-hardness distribution of the previous micro-bending experiments of CuZn37 a-brass foils with coarse grains and fine grains. Comparison of the simulated dislocation densities distribution of SSDs and GNDs with the experimental results shows that different micro-hardness distribution patterns of the coarse and fine grain foils can be attributed to the corresponding SSDs and GNDs distributions. The present model provides a physical insight into the deformation mechanism and dislocation densities evolution of the micro-bending process.
基金Project(2006AA04Z316)supported by the High-tech Research and Development Program of ChinaProject(2008RFQXG041)supported by the Foundation for Innovation Scholars of Harbin City,ChinaProject(50805035)supported by the National Natural Science Foundation for Young Scholars of China。
文摘Micro-bending tests were performed to investigate effects of thickness and grain size on material behavior in sheet metal forming.The rolling brass C2680 foil was selected as the experimental material,and it was annealed to eliminate the work-hardening and get different grain sizes.A device was specially designed for three-point bending with two load sensors.The results show that the bending force increases with increasing the punch displacement.With the foil of same thickness,a smaller punch radius leads to a larger bending force.When the grain size increases,the bending force becomes smaller.Size effects are observed obviously.These results have been analyzed by work-hardening,Hall-Petch equation and free surface effect.
