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61.
62.
Charles P.M. Jones G.G. Williams P.J. Ash R.M. Fell P.H. Carter A.C. 《Electronics letters》1991,27(9):700-702
The fabrication of buried ridge DFB lasers on semi-insulating substrates is described. A novel contacting mechanism was employed to give a series resistance of less than 4 Omega . Devices were fabricated at both 1.3 and 1.53 mu m with lasing thresholds as low as 16 mA. Single longitudinal mode operation was achieved with SMSR greater than 30 dB at both wavelengths. The structure gives an inherently low capacitance, which together with low threshold currents, low series resistance and fabrication on SI substrates makes these devices suitable for integration and high speed applications.<> 相似文献
63.
AUNIFEDTIME-MARCHINGPROCEDUREFORCOMPRESSIBLEINCOMPRESSIBLEFLOWS¥CharlesL.Merkle;FengJin-zhang(PropulsionEngineeringResearch,T... 相似文献
64.
Murti Krishna G. Stern Richard M. Cantekin Erdem I. Bluestone Charles D. 《IEEE transactions on bio-medical engineering》1982,(6):472-477
Spectral patterns of sound transmission through the Eustachian tube (ET) have been obtained in a series of experiments designed to identify ET dysfunction. Previous studies of ET function using sonometry have relied on heuristic and somewhat arbitrary methods in interpreting the data. In this study, an automated classification algorithm was developed to separate these sonograms into three distinct groups. From a total of 150 sample spectra, 75 were used in the formation of learning sets. The remaining spectra were classified into these three groups using standard Bayesian techniques. Both parametric and nonparametric methods were applied in estimating conditional probability density functions. Results of classification are compared with an independent test of ET function. Agreement between our classifier and the results of the independent test was as good as 97.3 percent. The results of this study indicate that an automated classification procedure can effectively distinguish among the three major types of sonograms obtained from ET sonometry. 相似文献
65.
Thomas J. Brumm Charles R. Hurburgh Jr 《Journal of the American Oil Chemists' Society》1990,67(5):302-307
Interest in marketing soybeans on the basis of protein and oil content is increasing. Producers, breeders, handlers and buyers
of soybeans need a method of evaluating soybean lots of different composition. A model is presented that predicts, given soybean
composition and processing conditions, the yield of crude soybean oil and soybean meal from the processing of soybeans in
a solvent extraction plant. From these yields, an estimated processed value (EPV) was calculated. For one set of price conditions,
the EPV of typical soybeans had a range of $0.93 per bushel if premiums were paid for meal protein in excess of specifications
and a range of $0.53 per bushel if meal protein premiums were not paid. Trading rules established by the National Oilseed
Processors Association for domestic meal markets have a significant effect on the value and composition of soybean meal. 相似文献
66.
Charles E. Baumgartner 《Journal of the American Ceramic Society》1990,73(3):516-520
The performance of a molten carbonate fuel cell (MCFC) is significantly eroded when fuel and oxidant gases are allowed to combine chemically as occurs with a loss of gas impermeability by the cell's electrolyte structure. This performance decline is eradicated when the cell's electrodes possess pore size distributions small enough to absorb sufficient electrolyte to act as a secondary gas barrier. Described here is a process for preparing composite MCFC NiO cathodes where the median pore size of the gas barrier region is varied from 3.2 to 0.4 μm by adjusting the starting powder's Ni/NiO ratio. When filled with liquid Li2 CO3 -38 mol% K2 CO3 at 923 K, these structures possess a gas pressure resistance of between 2.3 × 105 and 13.6 × 105 Pa, respectively. The incorporation of these composite cathodes in a MCFC can prevent the penetration of the oxidant gas into the fuel cell's interior. 相似文献
67.
Charles L. Rohn 《乙烯基与添加剂工艺杂志》1990,12(2):95-98
PVC is one of the most versatile and cost effective commercial polymers. A main limitation of PVC is optimizing its fabrication characteristics and end use properties with minimum adverse effect on either. PVC compounding technology is supersensitive due to effect of subtle variations in formulations causing “inspec” products during one production run and “out-of-spec” products in another. Large variations in properties are frequently due to improper mixing. Dynamic mechanical analyses provides a method of monitoring variations in mixing and their affect on morphological structure deviations which can lead to poor processing and end use properties. 相似文献
68.
Garrocho Charles T. B. da Silva Maurício J. Oliveira Ricardo A. R. 《Wireless Networks》2020,26(1):373-386
Wireless Networks - D2D (device-to-device) communication is one of the developments of 5G networks (5th generation mobile networks) that reduce mobile traffic load, reduce energy consumption and... 相似文献
69.
The spherical homeomorphism conjecture, proposed by Shattuck and Leahy in 2001, serves as the backbone of their algorithm to correct the topology of magnetic resonance images of the human cerebral cortex. Using a canonical image-thickening technique and the authors' previously proven "spherical homeomorphism theorem for surfaces," we formulate and prove a spherical homeomorphism theorem which is valid for all digital images when utilizing the (26,6)-connectivity rule. 相似文献
70.
Matthew J. La Pan T. Charles Clancy Robert W. McGwier 《Wireless Communications and Mobile Computing》2016,16(2):177-191
Orthogonal frequency‐division multiplexing (OFDM) has become the manifest modulation choice for 4G standards. Timing acquisition and carrier frequency offset synchronization are prerequisite to OFDM demodulation and must be performed often. Most of the OFDM methods for synchronization were not designed with security in mind. In particular, we analyze the performance of a maximum likelihood synchronization estimator against highly correlated jamming attacks. We present a series of attacks against OFDM timing acquisition: preamble whitening, the false preamble attack, preamble warping, and preamble nulling.The performance of OFDM synchronization turns out to be very poor against these attacks, and a number of mitigation strategies and security improvements are discussed. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献