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301.
302.
Mohammad Khosravi Ross W. Boulanger Daniel W. Wilson C. Guney Olgun Lisheng Shao Shuji Tamura 《Soils and Foundations》2019,59(4):966-981
Equivalent-static pushover analyses with a three-dimensional (3D), nonlinear, finite-difference model are used to investigate the static and seismic stresses imposed on soil-cement grid reinforcements in soft clay profiles by overlying structures supported by shallow footings. The goal is to evaluate the potential stress concentrations in the soil-cement grid during foundation rocking and the potential for large foundation settlements associated with the local crushing of the soil-cement. The numerical analyses are first validated using data from dynamic centrifuge experiments that included cases with and without large foundation settlements and localized crushing of the soil-cement grids. The experimental and numerical results indicate that the stresses imposed on the soil-cement grid by the overlying structures must account for foundation rocking during strong shaking and stress concentrations at the soil-cement grid intersections. The numerical analyses provide reasonable predictions of the structural rocking loads and the zone of the expected crushing or lack of crushing, but underestimate the accumulation of foundation settlements when the seismic demands repeatedly exceed the soil-cement strength. The simulated moment-rotation and uplift behavior of the footings under monotonic lateral loading are reasonably consistent with the dynamic centrifuge test results. Parametric analyses using the validated numerical model illustrate how the stress transfer varies with the area replacement ratio, the thickness of the top sand layer, the properties of the bearing sand layer, and the relative stiffness of the soil-cement and the surrounding soil. A design model for estimating the stresses imposed on a soil-cement grid by rocking foundations was developed and shown to provide a reasonable basis for assessing whether or not local damage to the soil-cement grid is expected. 相似文献
303.
通过讨论干热岩对其附近岩层磁性和电性的影响,结合磁法和大地电磁法勘查的发展现状,提出了利用航空和地面综合地球物理方法开展干热岩勘探的思路设想,即利用航磁测量、航空天然场电磁测量(ZTEM)及大地电磁测量(MT)综合方法互相配合、优势互补,利用磁化强度矢量反演得到地下三维磁化率分布特征模型,利用印模法将ZTEM与MT数据有机结合起来,得到较大面积的地下三维视电阻率特征模型,磁电综合分析,实现快速勘探干热岩,加快我国开发和利用新型清洁能源——地热能的步伐。 相似文献
304.
从多个角度论述了机器翻译常用的方法,并通过一些实例的分析对现有机器翻译系统进行了分析研究;最后得出结论并对机器翻译的未来进行展望。 相似文献
305.
Jan Borovi?ka Pavel Kotrba Martin Mihaljevi? Jan Rohovec Tjakko Stijve 《The Science of the total environment》2010,408(13):2733-2744
Macrofungi are effective accumulators of Ag. This study provides a comprehensive review of this phenomenon supported by original data on the Ag concentrations of macrofungi from pristine and Ag-polluted areas. In pristine areas, the median Ag concentrations of ectomycorrhizal (ECM) and saprobic (SAP) macrofungi were 0.79 and 2.94 mg kg− 1, respectively. In these areas, hyperaccumulation thresholds for Ag in ECM and SAP macrofungi are proposed as 100 and 300 mg kg− 1, respectively. In a Ag-polluted area, the Ag concentrations in macrofungi (ECM and SAP) were significantly elevated with the median value of 24.7 mg kg− 1 and the highest concentrations in Amanita spp. of the section Vaginatae (304-692 mg kg− 1). The intracellular speciation of Ag in fruit-bodies of the Ag-accumulator Amanita submembranacea was inspected by size exclusion chromatography followed by sulfhydryl-specific fluorimetric assays of ligands using reverse phase high-performance liquid chromatography and improved polyacrylamide gel electrophoresis. Virtually all Ag was found to be intracellular and sequestered in the major 7 kDa and minor 3.3 kDa complexes. The lack of glutathione and phytochelatins and the presence of a single 3 kDa sulfhydryl-containing peptide in the isolated Ag-complexes suggest that detoxification of Ag in A. submembranacea may rely on metallothionein. Vertical distribution of Ag in a polluted forest soil profile has shown substantial enrichment in organic horizons; in polluted technosol, the highest Ag concentrations were found in surface layers. Standardized EDTA extraction of Ag in both the investigated soil profiles showed relatively low Ag extractibility, generally within the range of 2.2-7.7% of total Ag content. 相似文献
306.
Discriminative Latent Model (DLM) is proposed for Multiword Expressions (MWEs) extraction in Chinese text to improve the performance of Machine Translation (MT) system such as Template Based MT (TBMT). For MT systems to become of further practical use, they need to be enhanced with MWEs processing capability. As our study towards this goal, we propose DLM, which is developed for sequence labeling task including hidden structures, to extract MWEs for MT systems. DLM combines the advantages of existing discriminative models, which can learn hidden structures in sequence labeling task. In our evaluations, DLM achieves precisions ranging up to 90.73% for some type of MWEs, which is higher than state-of-the-art discriminative models. Such results demonstrate that it is feasible to automatically identify many Chinese MWEs using our DLM tool. With MWEs processing model, BLEU score of MT system has also been increased by up to 0.3 in close test. 相似文献
307.
TaqMan探针荧光定量PCR检测花生油中掺入棕榈油的研究 总被引:1,自引:0,他引:1
根据棕榈内源基因MT3 -B设计引物和TaqMan探针,采用基因重组技术构建用于检测棕榈基因MT3 -B的重组质粒作为绝对定量标准品,建立标准曲线,对花生油中掺入棕榈油1% ~40%梯度混合油品提取DNA进行棕榈成分定量检测.结果表明,重组质粒标准品荧光定量标准曲线对数线性回归分析相关系数(R2)为0.996;花生油中掺入棕榈油达到5%时,可检出每亳升混合油品中棕榈MT3 -B基因17.431 copies,检测的重复性和特异性好. 相似文献
308.
文章简要介绍了MIL—STD-1553总线的完备的接口芯片BU-61580的工作原理及其特点,并介绍了作为当前1553总线应用系统中使用最多的器件,它是如何在3种不同的工作模式(BC\RT\MT)下运行的。具体分析了DSP芯片微处理器ADSP2101是如何与BU-61580进行连接,以及在不同配置下连接方式的差异。 相似文献
309.
利用MT(Mobile Terminal)的宽屏和大存储量的优点,结合其软件平台和硬件结构特点,给出了基于MT的LRC(Lyrics)同步设计方案.根据LRC(Lyrics)结构特点编写了LRC(Lyrics)解析算法,二分法实现快速搜索和排序,编程实现功能,实用和软件测试证明了设计合理及系统的稳定性. 相似文献
310.
Ideally, we might hope to improve the performance of our MT systems by improving the system, but it might be even more important to improve performance by looking for a more appropriate application. A survey of the literature on evaluation of MT systems seems to suggest that the success of the evaluation often depends very strongly on the selection of an appropriate application. If the application is well-chosen, then it often becomes fairly clear how the system should be evaluated. Moreover, the evaluation is likely to make the system look good. Conversely, if the application is not clearly identified (or worse, if the application is poorly chosen), then it is often very difficult to find a satisfying evaluation paradigm. We begin our discussion with a brief review of some evaluation metrics that have been tried in the past and conclude that it is difficult to identify a satisfying evaluation paradigm that will make sense over all possible applications. It is probably wise to identify the application first, and then we will be in a much better position to address evaluation questions. The discussion will then turn to the main point, an essay on how to pick a good niche application for state-of-the-art (crummy) machine translation. 相似文献