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M. Hossein Taghavi Arshan Naji Leonid Belostotski James W. Haslett 《Analog Integrated Circuits and Signal Processing》2013,77(2):221-233
This paper discusses the use of mutli-path inductorless transimpedance amplifiers (TIAs), consisting of several different second-order shunt-feedback sub-TIAs (SF-sTIAs) driven by the photodiode, to break the single-stage technology-dependent transimpedance limit. The advantage of the MP-TIA that is explored in this work is in its third-order transfer function, which provides additional degrees of freedom in tailoring the performance. Pole and zero locations of the MP-TIA transfer function are examined and verified with behavioural simulations. The theoretical transimpedance limit for MP-TIAs based on two SF-sTIAs is derived. The possibility of further increasing the transimpedance limit vs bandwidth trade-off by combining three and four sub-TIAs is investigated with simulations. A transistor-level design example of an MP-TIA is presented. The 0.13-μm CMOS MP-TIA achieves the largest figure-of-merit among published TIAs. 相似文献
44.
New efficient intermetallide catalysts for hydrogen storage in reversible processes of aromatics hydrogenation and naphthene dehydrogenation were studied. These catalysts provide an enhanced activity in the dehydrogenation of saturated organic molecules, with no side reactions like cracking, hydrogenolysis, ring opening, or coke formation occurring on these catalysts. The use of intermetallides provides some hydrogen storage capacity in the low-temperature region, while their catalytic activity in the dehydrogenation affords the hydrogen supply in the high-temperature range. 相似文献
45.
A failure mechanism of submarine landslides based on the phenomenon of shear band propagation has been investigated using
the energy balance approach. Dynamic analysis includes inertia effects in the sliding layer and viscous resistance of the
water, but ignores elastic and plastic wave propagation in the sliding layer. The resulting differential equation has been
solved numerically. Analytical approximation of this numerical solution provides a convenient basis for the parametric and
sensitivity studies. The solution allows assessing the velocity and acceleration of both the landslide and the shear band
at the moment when the slide fails due to the limiting equilibrium (i.e., the initial post-failure velocity). The effects
of the initial landslide velocity on the tsunami wave height are discussed and validated for a number of landslide examples. 相似文献
46.
A liquid-cell shearing interferometer was developed to measure refractive-index variations (delta n) in transparent materials. The cell was filled with a liquid having a matched refractive index. The achieved resolution was better than 1/1000 of a fringe shift and resulted in a delta n measurement sensitivity down to 10(-7) for 1-mm-thick samples. A refractive-index increment in photothermorefractive glass of up to 5 x 10(-6) was observed after UV exposure at 325 nm. A refractive-index decrement of up to 1 x 10(-3) was observed after thermal development of the exposed sample. It was proved that photothermorefractive glass obeys the reciprocity law; i.e., delta n depends on the UV dosage but does not depend on the irradiance. 相似文献
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The near-normal-incidence efficiencies of a 2400-groove/mm holographic master grating, a replica grating, and a multilayer grating are modeled in the soft-x-ray-extreme-ultraviolet (EUV) regions and are compared with efficiencies that are measured with synchrotron radiation. The efficiencies are calculated by the computer program PCGrate, which is based on a rigorous modified integral method. The theory of our integral method is described both for monolayer and multilayer gratings designated for the soft-x-ray-EUV-wavelength range. The calculations account for the groove profile as determined from atomic force microscopy with a depth scaling in the case of the multilayer grating and an average random microroughness (0.7 nm) for the short wavelengths. The refractive indices of the grating substrate and coatings have been taken from different sources because of the wide range of the wavelengths (4.5-50 nm). The measured peak absolute efficiency of 10.4% in the second diffraction order at a wavelength of 11.4 nm is achieved for the multilayer grating and is in good agreement with a computed value of approximately 11.5%. Rigorous modeling of the efficiencies of three similar gratings is in good overall agreement with the measured efficiency over a wide wavelength region. Additional calculations have indicated that relatively high normal incidence efficiency (of at least several percent) and large angular dispersion in the higher orders can be achieved in the 4.5-10.5-nm range by application of various multilayer coatings. 相似文献
49.
Sigal L Sclaroff S Athitsos V 《IEEE transactions on pattern analysis and machine intelligence》2004,26(7):862-877
A novel approach for real-time skin segmentation in video sequences is described. The approach enables reliable skin segmentation despite wide variation in illumination during tracking. An explicit second order Markov model is used to predict evolution of the skin-color (HSV) histogram over time. Histograms are dynamically updated based on feedback from the current segmentation and predictions of the Markov model. The evolution of the skin-color distribution at each frame is parameterized by translation, scaling, and rotation in color space. Consequent changes in geometric parameterization of the distribution are propagated by warping and resampling the histogram. The parameters of the discrete-time dynamic Markov model are estimated using Maximum Likelihood Estimation and also evolve over time. The accuracy of the new dynamic skin color segmentation algorithm is compared to that obtained via a static color model. Segmentation accuracy is evaluated using labeled ground-truth video sequences taken from staged experiments and popular movies. An overall increase in segmentation accuracy of up to 24 percent is observed in 17 out of 21 test sequences. In all but one case, the skin-color classification rates for our system were higher, with background classification rates comparable to those of the static segmentation. 相似文献
50.
Changing in lipid spectrum, immunological state and coagulation in the 68 patients with IHD and atherogenic dyslipidemia who were taking biomass microalga Spirulina platensis was investigated. Modification of traditional plan of therapy of IHD when adding microalga Spirulina p. influences correcting effect to cascade procoagulation and immunopathological reactions, characteristic of atherosclerosis process. 相似文献