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991.
992.
Thin electromagnetic absorber such as less than 2~3 mm will be required for wireless LAN for domestic and business use together with millimeter wave broadcasting in the future. To make a thin construction, many resonators with lossy material were used. This paper present theoretical results that are useful for absorber designs 相似文献
993.
Analyzes the data of sociologic study carried out among head physicians of therapeutic and prophylactic institutions of the Novosibirsk region, who were asked to express their opinions on the principal problems of public health and its reformation. Although the majority of respondents consider the reforms necessary, almost half of them are sure that the direction of reforms is wrong. 相似文献
994.
The accuracy and efficiency of the self-consistent (regarding the electric field) Monte Carlo model, nonself-consistent Monte Carlo model, and the soft-threshold lucky electron model (LEM) for the calculation of substrate currents in deep sub-μm n-MOSFET's are investigated. While the two Monte Carlo models are in good agreement with the experiment, the simpler LEM model still gives reasonable results even for a 0.16 μm n-MOSFET. On the other hand, huge differences in the CPU time consumption are found and the LEM is about four orders of magnitude faster than the self-consistent Monte Carlo simulations. The nonself-consistent calculations are only one order of magnitude slower than the LEM. The good agreement with the experiment is obtained without considering the so-called surface impact ionization or any fitting of parameters on the device level 相似文献
995.
996.
997.
RM Johnson Y Ravindranath M el-Alfy G Goyette 《Canadian Metallurgical Quarterly》1994,83(4):1117-1123
Chronic nonspherocytic hemolytic anemia has been observed in a recently described glucose-6-phosphate dehydrogenase (G6PD) variant, G6PDWayne. The mechanical properties of these erythrocytes and other G6PD variants were examined. The deformability of G6PD-deficient erythrocytes was normal, as determined by osmotic scan ektacytometry, and was not significantly affected by hemolytic crisis. In the common varieties of G6PD deficiency, the mechanical stability of the red blood cell (RBC) membrane was greater than normal, but G6PDWayne membranes were abnormally susceptible to shear-induced fragmentation. There was no evidence for a concurrent genetic defect in spectrin, because self-association constants and tryptic digests were normal. The fragility of G6PDWayne membranes appeared to be a consequence of oxidative damage to membrane thiol groups associated with a low glutathione (GSH) level in these RBCs. Associations among GSH level, thiol oxidation, and membrane instability were also found when a larger group of G6PD-deficient RBCs were examined. In normal erythrocytes, 1-chloro-2,4-dinitrobenzene was used to reduce GSH levels by 50%. Membrane thiol oxidation and membrane fragility both increased when these cells were kept at 4 degrees C for 3 to 5 days. Our findings suggest that chronic depletion of GSH leads to the destabilization of membrane skeleton through oxidation of membrane protein thiols. 相似文献
998.
The Trichuris muris-mouse model of intestinal helminth infection provides a convenient system to examine the immune mechanisms operating during acute and chronic infection. Particular subsets of helper T lymphocytes (CD4+Th cells) play an important role in regulating infection via the secretion of distinct groups of cytokines. Reciprocal activation of Th cell subsets is associated with either expulsion of the parasites from the intestine (Th2 cells) or chronic infection (Th1 cells). In vivo neutralization experiments using anti-cytokine monoclonal antibodies show that critical cytokines are involved, with interferon-gamma playing an important role in the establishment of chronic trichuriasis and interleukin-4 in expulsion of the parasite from the gut. This model has provided clear evidence of a crucial role for distinct cytokines in mediating host protection against intestinal helminth infection and that manipulation of the immune response through the Th cell-cytokine axis can benefit either the host or the parasite. As such, the T. muris model is poised to generate important new data relevant not only to intestinal helminthiasis but to the wider field of parasite immunity and infection in general. 相似文献
999.
1000.
As a typical data visualization technique, self-organizing map (SOM) has been extensively applied to data clustering, image analysis, dimension reduction, and so forth. In a conventional adaptive SOM, it needs to choose an appropriate learning rate whose value is monotonically reduced over time to ensure the convergence of the map, meanwhile being kept large enough so that the map is able to gradually learn the data topology. Otherwise, the SOM's performance may seriously deteriorate. In general, it is nontrivial to choose an appropriate monotonically decreasing function for such a learning rate. In this letter, we therefore propose a novel rival-model penalized self-organizing map (RPSOM) learning algorithm that, for each input, adaptively chooses several rivals of the best-matching unit (BMU) and penalizes their associated models, i.e., those parametric real vectors with the same dimension as the input vectors, a little far away from the input. Compared to the existing methods, this RPSOM utilizes a constant learning rate to circumvent the awkward selection of a monotonically decreased function for the learning rate, but still reaches a robust result. The numerical experiments have shown the efficacy of our algorithm 相似文献