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排序方式: 共有747条查询结果,搜索用时 15 毫秒
1.
Abhendra K. Singh Kaitlyn Kahle Hannah James Allison L. Horner Daniel Villaflor Zach Benedict 《Ceramics International》2021,47(12):17268-17275
In this study the effects of high temperature and moisture on the impact damage resistance and mechanical strength of Nextel 610/alumina silicate ceramic matrix composites were experimentally evaluated. Composite laminates were exposed to either a 1050°C isothermal furnace-based environment for 30 consecutive days at 6 h a day, or 95% relative humidity environment for 13 consecutive days at 67°C. Low velocity impact, tensile and short beam strength tests were performed on both ambient and environmentally conditioned laminates and damage was characterized using a combination of non-destructive and destructive techniques. High temperature and humidity environmental exposure adversely affected the impact resistance of the composite laminates. For all the environments, planar internal damage area was greater than the back side dent area, which in turn was greater than the impactor side dent area. Evidence of environmental embrittlement through a stiffer tensile response was noted for the high temperature exposed laminates while the short beam strength tests showed greater propensity for interlaminar shear failure in the moisture exposed laminates. Destructive evaluations exposed larger, more pronounced delaminations in the environmentally conditioned laminates in comparison to the ambient ones. External damage metrics of the impactor side dent depth and area directly influenced the post-impact tensile strength of the laminates while no such trend between internal damage area and residual strength could be ascertained. 相似文献
2.
du Burck F. Lopez O. El Basri A. 《IEEE transactions on instrumentation and measurement》2003,52(2):288-291
We have developed a narrow-band controller in the MHz range, based on a field-programmable gate array. It is used to control the probe beam intensity in frequency-modulated spectroscopy experiments with an acoustooptic modulator. The residual amplitude modulation at the modulation frequency (2.5 MHz) is reduced by 50 dB. The first-harmonic detection of the signals is operated in saturation spectroscopy of I/sub 2/ at 514.5 nm and 501.7 nm. A reduction of the background noise and a large increase in the signal-to-noise ratio are obtained. 相似文献
3.
A one-dimensional mesoscopic ring with one input and two output leads acts as a spintronic beam splitter. The spatial degree of freedom, i.e., the presence of two different possible output channels, gets intertwined with the spin direction as a consequence of quantum interference and spin-orbit interaction. We investigate this kind of spatial-spin correlation, and show that the output density operator contains no quantum entanglement in the important special case when the device polarizes a perfectly random input spin state. However, the correlations are in general not purely classical, we also present specific input states with maximal spatial-spin entanglement after the ring. 相似文献
4.
G.O. Phillips S. Al-Assaf A. du Plessis 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2007,265(1):390-393
Using a mediating alkyne gas during the radiation treatment prevents the degradation of natural and synthetic polysaccharides and proteins. The product has higher viscosity and is more elastic than the original material and, therefore, gives enhanced functionality. Protein, within demineralised bone, too can be modified to give enhanced osteoinductive capacity after transplantation. Thus new functionalities can be achieved from the new products produced in food and medical products. 相似文献
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In a patient wounded by a gunshot in the abdomen, the bullet was radiologically located intradurally at S1 level. Although she had no neurological deficit at admission, she developed pain and motor weakness a few days later. At operation the bullet was found at L4 level and its removal resulted in complete neurological recovery. 相似文献
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J. du Rouchet 《Journal of Petroleum Geology》1985,8(1):101-114
The first part of this study was published in the last issue, 7 , (4) 381–402, October 1984. The conclusion on p. 103, and references which follow, apply to both papers. 相似文献
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10.
多电压设计(multiple supply voltage,MSV)是降低SoC功耗的有效方法之一.为便于电压岛供电引脚的放置,提出了一种考虑电压岛边界约束的多电压布图算法.首先,基于切分树表示的布图解特点,提出一种边界检查算法快速确定所有模块的边界信息.其次,以优化功耗为目标采用改进动态规划方法进行多电压分配并构建电压岛.最后,以模拟退火算法作为搜索引擎对芯片的面积、线长和功耗进行协同优化.为减少SA迭代次数,采用了一个两阶段的降温策略.对GSRC电路的实验结果表明,该算法可获得满足边界约束的多电压布图,且和不考虑边界约束时相比,仅在功耗上平均增加5.2%. 相似文献