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161.
Recent advancement in nanoscience and nanotechnologies inspired a wide spectrum of uses of nanodimensional materials ranging from industrial sector to biomedical applications. Inorganic nanomaterials made of noble metals, which are corrosion-resistant, are often included as electrode modifiers in designing electrochemical chemosensors and biosensors because of their unique catalytic, electric, and surface-related properties. This review summarizes the developments in electrochemical biosensors with integrated in their architecture metal nanostructures reported mainly during the last two years with a summary on some of the commonly used methods for the synthesis of metallic nanostructures. Nanodimensional noble metal structures might be considered as multipurpose electrode modifiers because of their abilities to act at the same time as electrocatalysts, signal amplifiers, and tools for immobilization and spatial orientation of redox proteins/enzymes or other type of bioreceptors. 相似文献
162.
It is important to estimate the Signal-to-Noise Ratio(SNR) of unknown emitter signal accurately.In order to resolve the disadvantages of present algorithm,a novel method is proposed in this letter.We extract and normalize the information of zero frequency of received signal by the Wigner-Vile Distribution(WVD) transformation and then get the approximate power of original signal by mathematic transformation,at last,we get the estimate value of SNR by the known account formula of SNR.Simulation results show t... 相似文献
163.
164.
Yang Li Jian Dong Ke Chen Wei Guo 《International Journal of Infrared and Millimeter Waves》2008,29(7):663-672
This paper presents a signal-level simulation model for simulating the process that antenna array of Aperture Synthesis Radiometer
(ASR) collecting thermal radiation and transforming thermal radiation signal into radio frequency (RF) signal. By using the
equivalent complex baseband signals to represent the practical thermal radiation and RF signals, simulation efficiency is
improved significantly. The statistic characteristics of simulation results are found to match the corresponding theoretical
analysis well. Results of an imaging simulation experiment show that this model can be employed in ASR system-level simulator
design. 相似文献
165.
We prove a uniqueness theorem for two non-constant meromorphic functions sharing three values which improves a recent result of T.C. Alzahary. As a consequence of our main result we also improve a theorem of G. Brosch. 相似文献
166.
线路共享指的是,用户除了从自己归属的本地电话公司(ILEC)以外还能选择从其它运营公司(主要指CLEC)为自己提供数据业务,并且不必安装第二条电话线。线路共享为现有电话线路上开展数据业务竞争铺平了道路,它在美国被视作能否成功开放DSL市场的关键因素。本文对美国针对DSL发展问题出台线路共享政策以及线路共享政策出台后的实施状况加以报道。对于我国制定线路共享政策和实施管理提供参考。 相似文献
167.
168.
D. V. Rogers J. E. Allnutt 《International Journal of Satellite Communications and Networking》1986,4(1):1-11
Exploitation of the international 14/11 GHz communications bands will probably follow the same pattern as that of the 6/4 GHz bands. First, the available monopolarized bandwidth will be filled. Next, multiple beams that use spatial isolation to provide frequency reuse will be developed. Finally, full dual-polarized operation will be employed. In the 14/11 GHz bands, rain can cause appreciable attenuation and depolarization. In some instances, dual polarized links will be depolarization limited. If up-link power control is implemented on attenuation dominated paths, depolarization can again dominate, owing to interference constraints. In both cases, a measure of depolarization compensation needs to be introduced to reduce the impact of interference. Part I of this paper quantifies this problem and establishes a set of reference statistics which can be used to assess the need for impairment restoration. Part II will discuss several ways of reducing the system impact of path depolarization. 相似文献
169.
170.
On the Contrast in Visual Cryptography Schemes 总被引:16,自引:0,他引:16
A visual cryptography scheme is a method to encode a secret image SI into shadow images called shares such that certain qualified subsets of shares enable the ``visual' recovery of the secret
image. The ``visual' recovery consists of xeroxing the shares onto transparencies, and then stacking them. The shares of
a qualified set will reveal the secret image without any cryptographic computation.
In this paper we analyze the contrast of the reconstructed image in k out of n visual cryptography schemes. (In such a scheme any k shares will reveal the image, but no set of k-1 shares gives any information about the image.) In the case of 2 out of n threshold schemes we give a complete characterization of schemes having optimal contrast and minimum pixel expansion in
terms of certain balanced incomplete block designs. In the case of k out of n threshold schemes with we obtain upper and lower bounds on the optimal contrast.
Received 27 September 1996 and revised 13 February 1998 相似文献