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281.
Abdul Aleaf 《世界电子元器件》2007,(12)
概要
经过过去几十年的技术竞赛,汽车系统在引擎控制,自动防锁等的功能上已获得很大的改进.所有的汽车都在满足驾驶者体验感受、符合政府标准和削减生产成本等方面不断进行增值改进,以使其能够在炙热竞争中脱颖而出.而进一步的技术发展将会集中在将不同系统的信息综合,从而使每一个系统都可利用其他系统的数据或外来信息来改善效能表现. 相似文献
282.
283.
Much work has focused on traffic grooming in SONET/WDM ring networks. Previous work has considered many aspects of traffic grooming, including minimizing the number of ADMs, minimizing the number of wavelengths, considering different traffic models, using different network architectures, incorporating switching capability and so on. In this work, we study traffic grooming in unidirectional ring networks with no switching capability under both uniform traffic and non-uniform traffic models to reduce electronic multiplexing costs. Based on the clustering notion, we derive a general and tighter lower bound for the number of ADMs required in traffic grooming under the uniform all-to-all traffic model. This bound reduces to special cases obtained in previous work. We also derive general, tighter, and closed form lower bounds for the number of ADMs required under two non-uniform traffic models: the distance-dependent traffic model and the non-uniform symmetric traffic model. Cost-effective multi-phase algorithms that exploit traffic characteristics are then designed and studied to efficiently groom traffic streams under different traffic models. Our numerical and simulation results show that the proposed multi-phase algorithms outperform existing traffic grooming algorithms by using a fewer number of ADMs. Our algorithms in several cases also achieve the lower bounds derived. 相似文献
284.
M. Aljaz Beg Firoz Ahmad Abdul Razzao 《Journal of the American Oil Chemists' Society》1974,51(10):439-441
The alumina mixed copper soap pellets of different fatty acids (C6−C16) have been prepared. The pellets are used as membranes of electropositive character. The concentration potential studies
have been carried out with potassium chloride solutions. Transport number of counterions and selective ionic permeability
through these membranes have been calculated. The values of both these parameters increase with increase in the number of
C-atoms of the hydrocarbon chain of copper soaps. This seems to be due to lowering in solubility and increase in crosslinking
in the membrane material. 相似文献
285.
The letter presents an identification scheme incorporating a set of relays, which lessens the online computations, for discrete-time model reference adaptive systems (MRAS). 相似文献
286.
Hariyadi Soetedjo S. Ezrol Esham Idris Sabtu Y. Mohd Razman A.M. Abdul Fatah 《Microelectronics Journal》2006,37(10):1115-1118
Characterizations on the pseudomorphic High Electron Mobility Transistor structure under High-Resolution X-ray Diffraction (HRXRD) have been carried out at room temperature. Variation of Al contents in AlxGa1−xAs alloys has been found to show a shift of diffraction peaks. This variation is also found to show the change of lattice constant of crystal and also sheet carrier concentration as obtained from a Hall effect measurement. The latter phenomenon is considerably interesting to study in the early stage of the electrical properties of device based on the crystal structure. 相似文献
287.
288.
Sharifah Mohamad Wan Md Zin Wan Yunus Md Jelas Haron Mohd Zaki Abdul Rahman 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(11):1565-1569
BACKGROUND: The increasing demand for molybdenum has encouraged the development of low‐cost and environmentally friendly extractants to recycle and recover this metal. In the present study, solvent extraction of Mo(VI) from acidic media using a mixture of fatty hydrazides synthesised from palm olein as the extractant was carried out. The effects of various parameters such as acid, diluent, contact time, extractant concentration, metal ion concentration and stripping agent and the separation of Mo(VI) from other metal ions such as Co(II), Ni(II), Al(III) and Mn(II) were investigated. RESULTS: It was found that the extraction of Mo(VI) into the organic phase involved the formation of 1:3 complexes. Mo(VI) was successfully separated from commonly associated metal ions such as Ni(II), Co(II), Al(III) and Mn(II). Mo(VI) stripping from the loaded organic phase was studied using different acidic and alkaline solutions and was found to be optimal with ammonium hydroxide solution. CONCLUSION: These results are useful for the development of a method to recover Mo(VI) from acidic media utilising fatty hydrazides as the extractant. Copyright © 2008 Society of Chemical Industry 相似文献
289.
Using simulated presbyopia we measured the effects of target vergence and pupil size on letter contrast sensitivity while subjects wore accurately centered simultaneous vision bifocal contact lenses. These experiments examined the increase in depth of focus provided by two bifocal contact lenses, and the effects of pupil size on near and distance vision. Monocular contrast sensitivity was assessed with three different designs of soft contact lenses. First, as a single vision control, we measured contrast sensitivity with a Bausch & Lomb, Optima 38 lens corrected for distance. We then measured contrast sensitivity with an Allergan Optical, Hydron Echelon, which is a diffractive simultaneous bifocal and a CIBA Vision, Spectrum, which is a concentric design, center-near, two-zone simultaneous vision bifocal. In general both bifocal contact lenses improved contrast sensitivity at near but decreased contrast sensitivity at distance (when compared to the single vision lens). With a fixed 3.5-mm artificial pupil, the Echelon lens had two clear peaks of sensitivity, one at distance (0.00 D) and one at near (-2.00 D), but the Spectrum lens had no clear peaks. Performance of the Spectrum lens depended on its center zone size. Near (-2.00 D) and distance (0.00 D) contrast sensitivity was measured with pupil sizes that ranged from 1 to 6 mm. The results showed that visual performance with a diffractive lens was almost independent of pupil diameter up to 3 to 4 mm but, as predicted, performance with the two-zone lens depended critically on pupil size. 相似文献
290.
When a smooth swirling jet of water impinges vertically on a horizontal plane it spreads outwards forming a boundary layer on the plane. At large radial distance r, the flow is completely absorbed by the boundary layer and in this region a similarity solution is obtained. 相似文献