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91.
The singularity expansion method (SEM) is used to represent the current on a loaded loop antenna. The shift in the poles of the loop due to impedance loading can be analyzed using contour plots in the complex frequency plane of the Fourier modal impedance transfer functions. The same plot may also be used to determine a loading function which will yield a specified pole pattern leading to frequency or time domain synthesis. A simple example of time-domain synthesis is presented. 相似文献
92.
John D. Blackburn 《Computers & Education》1980,4(4):287-292
A strategy for the design of social science software is outlined concentrating particularly on the nature of packages, languages, data structures and characteristics of procedures. 相似文献
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Dultsev FN Speight RE Fiorini MT Blackburn JM Abell C Ostanin VP Klenerman D 《Analytical chemistry》2001,73(16):3935-3939
We show that it is possible to detect specifically adsorbed bacteriophage directly by breaking the interactions between proteins displayed on the phage coat and ligands immobilized on the surface of a quartz crystal microbalance (QCM). This is achieved through increasing the amplitude of oscillation of the QCM surface and sensitively detecting the acoustic emission produced when the bacteriophage detaches from the surface. There is no interference from nonspecifically adsorbed phage. The detection is quantitative over at least 5 orders of magnitude and is sensitive enough to detect as few as 20 phage. The method has potential as a sensitive and low-cost method for virus detection. 相似文献
96.
Hao Zhang T.R. Blackburn B.T. Phung D. Sen 《Dielectrics and Electrical Insulation, IEEE Transactions on》2007,14(1):3-14
Medium and high voltage power cables are widely used in the electrical industry with substantial growth over the last 20-30 years ago, particular in the use of XLPE insulated systems. Ageing of the cable insulation is becoming an increasing problem that requires development of reliable methods for on-line condition assessment. For insulation condition assessment of MV and HV cables, partial discharge (PD) monitoring is one of the most effective techniques. However on-site and on-line PD measurements are affected by electromagnetic interference (EMI) that makes sensitive PD detection very difficult, if not impossible. This paper describes implementation of wavelet transform techniques to reject noise from on-line partial discharge measurements on cables. A new wavelet threshold determination method is proposed with the technique. With implementation of this novel de-noising method, PD measurement sensitivity has been greatly improved. In addition, a full AC cycle data recovery can be achieved instead of focusing only on recovering individual PD pulses. Other wavelet threshold de-noising methods are discussed and examined under a noisy environment to compare their performance with the new method proposed here. The method described here has been found to be superior to the other wavelet-based methods 相似文献
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Bracken presents a serious environmental problem in many regions of the world and remote sensing offers the potential of monitoring the invasion and management of this plant. This study evaluates this potential by reporting the results of an investigation of the relationships between the biophysical properties of a bracken canopy and its spectral reflectance and how such relationships are effected by view angle. An experiment was carried out through the bracken growing season at sites in West Sussex, UK. In the principal plane of the Sun, red reflectance becomes lower and relatively less variable with view angle as the canopy develops, while near-infrared reflectance increases and becomes relatively more variable with view angle. As Leaf Area Index (LAI) increases, the variability of the Normalized Difference Vegetation Index (NDVI) with view angle decreases, while the simple ratio vegetation index (SR) behaves in almost the opposite manner. Polar plots, illustrating full directional reflectance distributions, reveal that as the canopy develops the hot spot in red reflectance at the retro-solar angle diminishes, to be replaced by enhanced red reflectance at high zenith angles in the forward-scatter direction. Near-infrared reflectance behaves very differently, as a hot spot at the retro-solar angle becomes more pronounced as the canopy grows. The angular distribution of NDVI and SR varies markedly over the growing season, however both indices are well correlated with canopy biophysical properties for most view angles sampled, apart from the extreme off-nadir. Red edge position was largely insensitive to view angle, but had a good correlation with LAI, as did percenage reflectance at the red edge position. 相似文献
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S Kozlowski M Corr M Shirai LF Boyd CD Pendleton JA Berzofsky DH Margulies 《Canadian Metallurgical Quarterly》1993,151(8):4033-4044
T cell stimulation by certain class I-restricted antigenic peptides, such as the HIV 1 gp160-derived peptide, P18, requires peptide processing by angiotensin-1 converting enzyme (ACE) in FCS. We observed that longer versions of P18 and the murine cytomegalovirus pp89-derived core peptide, pMCMV, which could stimulate T cell hybridomas in FCS, were not as sensitive to the ACE inhibitor captopril as P18. Using cell-free soluble murine class I MHC molecules and protease inhibitors, we found that there are pathways of differing efficiency that use enzymes other than ACE for the proteolytic processing of peptides in serum. The kinetics of the generation of T cell stimulatory activity among P18 variant peptides in serum differed with peptide length, and with the nature of amino and COOH-terminal extensions. Such processing occurs in human plasma as well as in FCS. The understanding of this processing, its kinetics, and its inhibitors can lead to better design of peptide-based therapies, including vaccines. 相似文献
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