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181.
Hwang H.-K. Lee L.-S. Chen S.-H. 《Selected Areas in Communications, IEEE Journal on》1989,7(9):1450-1461
Multi-H phase-coded modulation (MHPM) is a bandwidth-efficient modulation scheme which offers substantial coding gain over conventional digital modulation schemes. MHPM with asymmetric modulation indices corresponding to the bipolar data +1 and -1 is considered, and numerical results for the minimum Euclidean distances are provided. It is shown that performance improvements on the error probability over conventional MHPM are gained with essentially the same bandwidth and a very slight modification in implementation. The upper bounds on the error probabilities as functions of observation intervals and received E b/N 0 are also investigated in detail. It is concluded that the concept of asymmetric modulation indices for MHPM is attractive for bandwidth and power-efficient modulation 相似文献
182.
183.
Survival of rotavirus on lettuce, radishes, and carrots was studied to evaluate the potential of rotavirus transmission by vegetables irrigated with wastewater. The vegetables were contaminated with rotavirus SA-11 and stored at 4°C and room temperature in covered and uncovered containers to simulate post harvest conditions. Virus decay rates were greater on radishes and carrots than lettuce. Decay rates of rotavirus on lettuce, radish, and carrot ranged from ?0·057 to ?0·479 (log10 pfu/day). Rotavirus SA-11 survived on lettuce, radish, and carrot for 25 to 30 days at 4°C but at room temperature survival was very different for the various vegetables varying from 5 to 25 days. Greatest survival was always observed on the lettuce. These data suggest that rotaviruses can survive long enough on contaminated vegetables as to be transmitted by this vehicle. 相似文献
184.
Understanding how the structure of the unit-cell affects the cryogenic performance of a Si power Metal Oxide Semiconductor Field Effect Transistor (MOSFET) is an important step toward optimizing of the device for cryogenic operations. In this paper, numerical simulations of the Si power Double Diffused MOSFET’ (DMOS) are performed at room temperature and cryogenic temperatures. Physically based models for temperature dependent silicon properties are employed in the simulations. The performances of power DMOS’ with various unit-cell structures are compared at both room temperature and low temperatures. The effect of the cell structure on the on-resistance and breakdown voltage of the device are analyzed. The simulation results suggest that the device optimized for room temperature operation can be further optimized at cryogenic temperatures. 相似文献
185.
W. Lee 《Journal of power sources》1985,16(2):131-140
The structure of sintered nickel composite plaque is characterized by an irregular pore structure with a wide distribution of pore sizes as well as a l 相似文献
186.
Due to the rugged energy function of the original Hopfield networks, the output is usually one local minimum in the energy function. An analysis on the locations of local minima in Hopfield networks is presented, and a modified network architecture to eliminate such local minima is described. In particular, another amplifier is introduced at the processor nodes to give correction terms. This modified Hopfield network has been successfully applied to the construction of analog-to-digital converters with optimal solutions. Experimental results on the voltage transfer characteristics of data converters are presented. 相似文献
187.
Zautra Alex J.; Okun Morris A.; Robinson Sharon E.; Lee Douglas; Roth Sanford H.; Emmanual Jansen 《Canadian Metallurgical Quarterly》1989,8(1):1
Studied the relation between life stress and immune parameters for 33 30–70 yr old female rheumatoid arthritis (RA) patients interviewed during 3 routine monthly clinic checkups. Life stress from major and minor events, coping efficacy, and self-reported psychological distress were assessed, and immunofluorescence of T-cells and B-cells was performed on the blood drawn during each visit. Small stressful events were positively related to the proportion of circulating B-cells, psychological distress was inversely related to proportion of circulating T-cells, and major life events were associated with lower T-helper/T-suppressor cell ratios. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
188.
Lee C.K. Hui S.Y.R. Shu-HungChung H. Shrivastava Y. 《Power Electronics, IEEE Transactions on》2002,17(1):94-100
In this paper, a feasibility study of a randomized space vector switching scheme for three-level inverters is reported. Based on the traditional space vector concept for pulse width modulation (PWM) inverters, the sequence of the space vector is randomized in this scheme. The overall vector, resulting from the randomization, is mathematically identical to that of the traditional space vector. It has been found that the randomized scheme can effectively spread the switching noise over a wide frequency range and at the same time keep the steady-state link capacitor voltage balanced. The proposed scheme has been implemented in real time in a digital controller and its features have been experimentally confirmed 相似文献
189.
Biing-Lin Lee 《Polymer Engineering and Science》1985,25(12):729-740
The physical properties of finished polymer blend composites are, in general, strongly influenced by the heterogeneity of the blend and the distribution of ingredients (especially reinforcement fillers) in each of the polymer phases. In this article, we review and update a processing technology specifically for the processing of multiphase rubber blend compounds in order to produce blend compounds with more desirable properties for practical applications. The basic concept is centered on the controlled-ingredient-distribution mixing (CIDM) process. The improvements in the following properties of rubber blend compounds are discussed: crack growth resistance, heat buildup, oil swelling, covulcanization, green strength, and permeability. 相似文献
190.