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151.
A scheme to reduce the size of a microstrip antenna is investigated both theoretically and experimentally. For a given operating frequency the patch length is significantly reduced when microstrip width discontinuities are introduced in the middle of the antenna patch 相似文献
152.
153.
Tzung-Pei Hong Shian-Shyong Tseng 《Knowledge and Data Engineering, IEEE Transactions on》1999,11(5):813-815
We have modified the original version space strategy in order to learn disjunctive concepts incrementally and without saving past training instances. The algorithm time complexity is also analyzed, and its correctness is proven 相似文献
154.
High Strength Low Alloy (HSLA) steel exhibits good ductility at low temperatures down to 77 K in both ferrite-pearlite and
dual-phase structures. The instantaneous strain-rate sensitivity (m) increases with decreasing temperature and reaches a maximum at 100 K. This peak temperature is much lower than that for
plain carbon steels. The post-uniform elongation, which is more sensitively dependent onm, shows only slight increase around 100 K. The effect ofm on the post-uniform elongation is probably mitigated by the increasing dependence ofm on strain rate above 180 K. The uniform elongation, normally associated with the strain hardening characteristics of the
material, also shows some increase around 100 K. Therefore, both strain-hardening and strain-rate hardening are responsible
for the enhanced ductility of HSLA steel around 100 K. 相似文献
155.
Let X and Y be two strings of lengths n and m, respectively, and k and l, respectively, be the numbers of runs in their corresponding run-length encoded forms. We propose a simple algorithm for computing the longest common subsequence of two given strings X and Y in O(kl+min{p1,p2}) time, where p1 and p2 denote the numbers of elements in the bottom and right boundaries of the matched blocks, respectively. It improves the previously known time bound O(min{nl,km}) and outperforms the time bounds O(kllogkl) or O((k+l+q)log(k+l+q)) for some cases, where q denotes the number of matched blocks. 相似文献
156.
157.
To investigate the effects of morphine on neutrophil and endothelial activation, we measured serum levels of intercellular adhesion molecule-1 (ICAM-1), L-selectin, and neutrophil endopeptidase 24.11 (NEP) in 38 patients with acute myocardial infarction (group 1) and 16 control subjects (group 2). In group 1, all the patients underwent blood sampling at initial presentation and 10 minutes later. Twenty of them had 3 mg of morphine administered intravenously immediately after the first sampling (group 1A) and the other 18 after a second sampling (group 1B). The serum levels of ICAM-1 and L-selectin were both significantly higher in groups 1A and 1B than in group 2. In group 1A, the ICAM-1 decreased significantly at second blood samplings (310 +/- 28 vs 368 +/- 30 ng/ml; p <0.001), whereas in group 1B there was no significant change in ICAM-1 (357 +/- 33 vs 359 +/- 26 ng/ml; p = NS). In group 1A, the L-selectin decreased significantly at second blood samplings (2.3 +/- 1.2 mg/L, p <0.001 vs baseline), whereas in group 1B there was no significant change in L-selectin (3.9 +/- 1.0 mg/L, p = NS vs baseline). There was no significant difference in baseline NEP activities between groups 1A and 1B (4.89 +/- 1.22 vs 5.14 +/- 1.57 nmol/mg protein; p = NS). However, the NEP activities at second blood samplings decreased significantly in group 1A (9.88 +/- 1.86 nmol/mg protein, p <0.001 vs baseline), whereas no significant changes were observed in group 1B (5.09 +/- 1.62 nmol/mg protein, p = NS vs baseline). In conclusion, morphine increased NEP activities and thus attenuated shedding of L-selectin and ICAM-1. 相似文献
158.
It is pointed out that the problem of selecting Weibull populations that are more reliable is complex; the main result is that there is no simple selection rule. Under type-II censoring, the use of a locally optimal selection rule when the shape parameters are known and the use of a modified selection rule when the unknown shape parameters have some prior distributions are proposed. The performance of this modified rule was tested extensively by simulation; this rule was shown to be quite robust for a variety of beta prior distributions 相似文献
159.
Many types of nonconventional rolls, including coated, sleeved, and carbide rolls, have been developed to improve roll surface
strength to increase roll life. A study of the thermal behavior of the rolling process with these nonconventional rolls is
presented in this article. A numerical model, previously developed for homogeneous rolls, has been modified to study the thermal
response resulting from coating, sleeve, and carbide. Both cold- and hot-rolling processes under typical operating conditions
are considered. First, a cold-rolling case previously considered was studied to demonstrate the validity of the modified version
and then several other cases were investigated to assess the effects of using nonconventional rolls. The numerical results
indicated that the effects of the coated, sleeved, and carbide rolls were favorable for increasing roll life. 相似文献
160.
Ming-Kwei Lee Chi-Hsing Chu Yu-Chu Tseng Jong-Min Shyr Chia-Hsiung Kao 《Electron Device Letters, IEEE》2000,21(12):587-589
A porous silicon Al Schottky barrier diode shows differential negative resistance. The thin wires in porous silicon have much lower electron mobility than that of thick wires, due to electron surface scattering from space confinement. The energy of carriers in thick wires increases with applied bias. Some carriers can overcome the conduction-band discontinuity and flow into the thin wires. The negative differential resistance comes from the mobility difference between thick wires and thin wires in porous silicon. 相似文献