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A high-performance CMOS line driver for ISDN U -interface transceiver applications has been designed and fabricated. Careful study of requirements and trade-offs affecting linearity, power efficiency, and quiescent current presented in this work has resulted in a circuit structure featuring a highly linear input/output characteristic and well-controlled quiescent current. The prototype line driver is capable of delivering a 5-Vpp signal of up tp 80 kHz to a 60-Ω load while exhibiting linearity on the order of 77 ± 5 dB and operating from a single 5-V power supply. Linearity better than 70 dB is maintained for load resistances as low as 20 Ω 相似文献
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Ghodratallah Shams Khorramabadi Reza Darvishi Cheshmeh Soltani Abbas Rezaee Ali R. Khataee Ahmad Jonidi Jafari 《加拿大化工杂志》2012,90(6):1539-1546
The objective of this investigation was to study the biosorption of Cr (VI) on immobilised activated sludge (IAS) and calcium alginate (CA) using batch system. The optimal pH for Cr (VI) biosorption by IAS and CA was 2.0 and 4.0, respectively. Equilibrium was attained at approximately 120 min for both biosorbents. For both biosorbents, the equilibrium biosorption capacity (mg/g) increased as the initial metal ion concentration increased and the concentration of biosorbent decreased. The rate of biosorption onto IAS and pure CA (as mg/g) increased from 5.02 to 87.66 and 4.97 to 79.09 as the concentration of Cr (VI) ions increased from 10 to 1000 mg/L, respectively. In the case of biosorbent concentration, as the concentration of IAS and pure CA increased from 1 to 20 g/L, the equilibrium uptake (qe) decreased from 21.33 to 1.57 and 19.41 to 1.38 mg/g, respectively. The biosorption data showed that the Langmuir model was more suitable than the Freundlich model. Also, the results indicated that the pseudo‐second order model was the most suitable for Cr (VI) biosorption onto IAS and CA. © 2011 Canadian Society for Chemical Engineering 相似文献
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The design and evaluation of a novel approach to reactor core power control based on emotional learning is described. The controller includes a neuro-fuzzy system with power error and its derivative as inputs. A fuzzy critic evaluates the present situation, and provides the emotional signal (stress). The controller modifies its characteristics so that the critic’s stress is reduced. Simulation results show that the controller has good convergence and performance robustness characteristics over a wide range of operational parameters. 相似文献
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C Cutting B Grayson JG McCarthy C Thorne D Khorramabadi B Haddad R Taylor 《Canadian Metallurgical Quarterly》1998,102(7):2436-2443
This article reports our clinical experience since 1994 with rigid-motion tracking of bone fragments during craniofacial surgical procedures, using a virtual reality approach. Three noncollinear infrared diodes are fixed to the skull base. A pointer is used to register anatomic features on the patient to those on the computerized tomography-based model of the patient within a computer work station. Three diodes are then attached to each fragment just before the osteotomy is completed. Rigid motions of the fragment are thus tracked and reported to the surgeon by using virtual reality techniques. Errors in fragment positioning are reported both graphically and numerically with respect to a precomputed optimum fragment position. This guidance system allows multisegment midface osteotomies to be performed more precisely. The main problems encountered so far have been devascularization-infection and difficulties in maintaining correct position during application of rigid fixation. Devascularization-infection problems have been addressed by minimizing surgical exposure of the bone. Soft-fixation plates and temporary Kirschner wire fixation have helped with intermediate positioning, but an intraoperative mechanical positioning device would be useful in the future. 相似文献
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