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41.
Su X Chakravarti D Cho MS Liu L Gi YJ Lin YL Leung ML El-Naggar A Creighton CJ Suraokar MB Wistuba I Flores ER 《Nature》2010,467(7318):986-990
42.
光纤裂缝传感器中裂缝宽度与光纤损耗关系分析 总被引:12,自引:0,他引:12
为了从理论上获得光纤裂缝传感器的性能。简化传感器的设计,用光射线理论分析了多模光纤的弯曲损耗,获得了混凝土裂缝宽度与光功率损耗之间的关系。并编程计算了传感器的裂缝宽度与光纤损耗的关系,光纤与裂缝的夹角对传感器性能的影响,以及改变光纤的数值孔径对传感器性能的影响.理论分析结果与实验结果吻合。 相似文献
43.
引人参数β=(√μx/μy),将正交各向异性板反平面裂纹问题的基本边值问题转换为正交各向同性的形式,反平面裂纹问题的位移和应力在正交各向同性和正交各向异性这两种情况之间的比拟关系非常简单,使问题的求解更为方便.为了说明这个比拟方法,分别求导了含有内部裂纹和边缘裂纹的正交各向异性板Ⅲ型二维裂纹问题的William's一般解.这些William's一般解对于用FFEM和其他数值方法来求解正交各向异性板反平面裂纹问题是一个非常重要的基础.研究结果表明这种比拟变换方法能有效地简化正交各向异性板Ⅲ型裂纹问题的求解. 相似文献
44.
基于GA的计算机数学试验Mm-LH设计 总被引:2,自引:0,他引:2
将遗传算法(GA)引入到计算机数学试验(CE)的研究中,在MmLH设计空间,给出新的位串编码规则及相应的遗传操作,从而得到一个构造MmLH设计的有效方法,与传统方法相比,它具有更高的构造效率比,并可将其用于其它准则的设计研究与构造中· 相似文献
45.
Leung JY Bennett WR Herbert RP West AK Lee PR Wake H Fields RD Chuah MI Chung RS 《Cellular and molecular life sciences : CMLS》2012,69(5):809-817
Prior studies have reported that metallothionein I/II (MT) promote regenerative axonal sprouting and neurite elongation of
a variety of central nervous system neurons after injury. In this study, we evaluated whether MT is capable of modulating
regenerative axon outgrowth of neurons from the peripheral nervous system. The effect of MT was firstly investigated in dorsal
root ganglion (DRG) explants, where axons were scratch-injured in the presence or absence of exogenous MT. The application
of MT led to a significant increase in regenerative sprouting of neurons 16 h after injury. We show that the pro-regenerative
effect of MT involves an interaction with the low-density lipoprotein receptor megalin, which could be blocked using the competitive
antagonist RAP. Pre-treatment with the mitogen-activated protein kinase (MAPK) inhibitor PD98059 also completely abrogated
the effect of exogenous MT in promoting axonal outgrowth. Interestingly, we only observed megalin expression in neuronal soma
and not axons in the DRG explants. To investigate this matter, an in vitro injury model was established using Campenot chambers,
which allowed the application of MT selectively into either the axonal or cell body compartments after scratch injury was
performed to axons. At 16 h after injury, regenerating axons were significantly longer only when exogenous MT was applied
solely to the soma compartment, in accordance with the localized expression of megalin in neuronal cell bodies. This study
provides a clear indication that MT promotes axonal regeneration of DRG neurons, via a megalin- and MAPK-dependent mechanism. 相似文献
46.
Genetic diversity and disease control in rice 总被引:169,自引:0,他引:169
Zhu Y Chen H Fan J Wang Y Li Y Chen J Fan J Yang S Hu L Leung H Mew TW Teng PS Wang Z Mundt CC 《Nature》2000,406(6797):718-722
Crop heterogeneity is a possible solution to the vulnerability of monocultured crops to disease. Both theory and observation indicate that genetic heterogeneity provides greater disease suppression when used over large areas, though experimental data are lacking. Here we report a unique cooperation among farmers, researchers and extension personnel in Yunnan Province, China--genetically diversified rice crops were planted in all the rice fields in five townships in 1998 and ten townships in 1999. Control plots of monocultured crops allowed us to calculate the effect of diversity on the severity of rice blast, the major disease of rice. Disease-susceptible rice varieties planted in mixtures with resistant varieties had 89% greater yield and blast was 94% less severe than when they were grown in monoculture. The experiment was so successful that fungicidal sprays were no longer applied by the end of the two-year programme. Our results support the view that intraspecific crop diversification provides an ecological approach to disease control that can be highly effective over a large area and contribute to the sustainability of crop production. 相似文献
47.
48.
Steidl C Shah SP Woolcock BW Rui L Kawahara M Farinha P Johnson NA Zhao Y Telenius A Neriah SB McPherson A Meissner B Okoye UC Diepstra A van den Berg A Sun M Leung G Jones SJ Connors JM Huntsman DG Savage KJ Rimsza LM Horsman DE Staudt LM Steidl U Marra MA Gascoyne RD 《Nature》2011,471(7338):377-381
49.
隧道开挖对周围土体及桩基影响的试验研究 总被引:2,自引:1,他引:1
通过离心机试验研究了粘土中隧道开挖引起的土体瞬时和长期沉降.对不同的隧道与桩间距情况进行了3组离心机试验,研究隧道开挖对桩基的瞬时和长期影响.试验结果表明,高斯曲线法计算的土体瞬时沉降与试验值比较吻合,而计算的长期沉降低估了地表沉降的影响范围.隧道开挖引起的桩身最大轴力和弯矩都发生在隧道起拱线附近,而且桩基反应都是随着... 相似文献
50.
This paper describes an investigation in the fabric longi-tudinal compressibility of thirty-one suiting and trouse-ring materials using a newly developed device attached to the advanced Instron extensometer Model4466.The at-tachment was designed mainly to ensure a correct align-meat of fabric plane at the start of compression.Usingthe newly developed testing method,fabric longitudinalcompression curve was obtained and the results of longi-tudinal compressibility measured by two different com-pression load ranges(from 0 to 0.5 N/m width and 0 to1 N/m width)were examined.In addition,their rela-tionships with the fabric low-stress mechanical proper-ties measured by the KES-F system were investigatedusing statistical analysis.The results clearly indicatedthat significant differences existed when substituting fab-ric longitudinal compressibility with fabric extensibilitymeasured using the KES-F system under a low-load.Significant infiuence of yarn rotational movement in fab-ric on the longitudinal compressibi 相似文献