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Most previous studies on concrete short columns confined with fiber-reinforced polymer (FRP) composites were based on small-scale testing, and size effect of the columns still has not been studied thoroughly. In this study, 99 confined concrete short columns wrapped with aramid FRP (AFRP) jackets and 36 unconfined concrete short columns with circular and square cross sections were tested under axial compressive loading. The circular specimens were divided into six groups, and the square specimens were divided into five groups, with each group containing different levels of the AFRP’s confinement. In each group, the specimens were geometrically similar to one another and had three different scaling dimensions. Statistical analyses were used to evaluate the size and interaction effects between the specimen size and the AFRP’s confinement, and a size-dependent model for predicting the strength of the columns was developed by modifying Baz?nt’s size-effect law. The experimental results showed that the size of a specimen had a significant effect on the strength of AFRP-confined concrete short columns, lesser effect on the axial stress-strain curves, and slight effect on the failure modes. The modified Baz?nt model was in good agreement with the experimental data. 相似文献
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Minseok S. Kim Jinhoon Kim Wonho Lee Sang‐Joon Cho Jin‐Mi Oh June‐Young Lee Sanghyun Baek Yeon Jeong Kim Tae Seok Sim Hun Joo Lee Goo‐Eun Jung Seung‐Il Kim Jong‐Myeon Park Jin Ho Oh Ogan Gurel Soo Suk Lee Jeong‐Gun Lee 《Small (Weinheim an der Bergstrasse, Germany)》2013,9(18):3103-3110
Circulating tumor cells (CTCs), though exceedingly rare in the blood, are nonetheless becoming increasingly important in cancer diagnostics. Despite this keen interest and the growing number of potential clinical applications, there has been limited success in developing a CTC isolation platform that simultaneously optimizes recovery rates, purity, and cell compatibility. Herein, a novel tracheal carina‐inspired bifurcated (TRAB) microfilter system is reported, which uses an optimal filter gap size satisfying both 100% theoretical recovery rate and purity, as determined by biomechanical analysis and fluid–structure interaction (FSI) simulations. Biomechanical properties are also used to clearly discriminate between cancer cells and leukocytes, whereby cancer cells are selectively bound to melamine microbeads, which increase the size and stiffness of these cells. Nanoindentation experiments are conducted to measure the stiffness of leukocytes as compared to the microbead‐conjugated cancer cells, with these parameters then being used in FSI analyses to optimize the filter gap size. The simulation results show that given a flow rate of 100 μL min?1, an 8 μm filter gap optimizes the recovery rate and purity. MCF‐7 breast cancer cells with solid microbeads are spiked into 3 mL of whole blood and, by using this flow rate along with the optimized microfilter dimensions, the cell mixture passes through the TRAB filter, which achieves a recovery rate of 93% and purity of 59%. Regarding cell compatibility, it is verified that the isolation procedure does not adversely affect cell viability, thus also confirming that the re‐collected cancer cells can be cultured for up to 8 days. This work demonstrates a CTC isolation technology platform that optimizes high recovery rates and cell purity while also providing a framework for functional cell studies, potentially enabling even more sensitive and specific cancer diagnostics. 相似文献
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针对船用柴油机工作不均匀及循环波动对柴油机性能和振动噪声的负面影响问题,以6L16/24-CR型船用中速柴油机为对象,使用软件在环仿真技术对缸压闭环控制策略进行仿真分析。建立能模拟各缸不均匀性和循环波动的柴油机实时模型,从气缸压力中选取能指示柴油机各缸燃烧状态的反馈变量,根据反馈变量和控制变量之间的动态关系开发缸压闭环控制策略,建立由柴油机实时模型、气缸压力反馈变量、控制策略和喷油控制变量构成的软件在环仿真平台,在该软件在环仿真平台上对缸压闭环控制策略进行闭环仿真。结果表明,开发的缸压闭环控制策略能满足船用柴油机的控制要求,在仿真环境下能改善约99%的各缸不均匀。 相似文献
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田晓庄 《计算机测量与控制》2015,23(3):838-841
为使专用短程通信设备相关参数测量结果更加准确可靠,测量水平与质量得到提高,根据JJF1059.1-2012测量不确定度评定与表示,对测量不确定度评定的方法进行分析;以专用短程通信设备载波频率及最大发射功率的测量为实例,详述了误差来源分析、数学模型建立、不确定度分量合成、扩展不确定度计算等评定过程;通过本方法而得到的测量不确定度,对专用短程通信设备相关参数测量结果的质量有了比较可靠的保证,并可用于指导组建测试系统、配置测试设备、分析测试结果等。 相似文献
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根据2008年9月采集的九龙江口-厦门湾大范围表层沉积物样品以及收集到的实测水文资料,分析研究九龙江口-厦门湾表层沉积物的粒度分布特征,同时在应用GSTA模型对沉积物进行输运趋势分析的基础上探讨该区域泥沙运移趋势.结果表明:九龙江口-厦门湾海域沉积类型较多,主要以黏土质粉砂为主,显示出该区域以细颗粒物质沉积为主的沉积特性,同时不同区域沉积物分布特征又略有差异,揭示了九龙江口-厦门湾各海区沉积物颗粒的粗细、水动力条件以及沉积环境的不同.应用GSTA模型对表层沉积物运移趋势分析结果显示,来自九龙江径流的物质一部分在九龙江口受到潮流作用沉积,一部分通过厦门湾口往外海输运,还有少量在涨潮流的作用下进入厦门西海域,该趋势与水动力条件密切相关. 相似文献
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针对船用低速机电液控制阀的可靠性问题,以自主研制的电液控制阀为研究对象,对前期性能试验反映出的问题进行总结,并通过FMECA方法逆推了造成电液控制阀失效的原因,以此为指导搭建了电液控制阀物理失效模型。在此模型基础上推导了电液控制阀泄漏失效模型,并通过可靠性试验验证了模型的准确性。基于此模型开展了电液控制阀的健康状态评估以及性能预测。研究结果表明:电液控制阀的主要失效形式为泄漏;阀芯累积变形量与碰撞次数之间成对数关系;泄漏模型计算值与实际试验值的误差在合理范围内。 相似文献
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Chin Cheng Siong Ji Xi Woo Wai Lok Kwee Tiaw Joo Yang Wenxian 《Neural computing & applications》2019,31(4):1127-1142
Neural Computing and Applications - A modified multiple generalized regression neural network (GRNN) is proposed to predict the noise level of various compartments onboard of the offshore platform.... 相似文献