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指数性质的数学测验问题 被引量:5
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作者 杨灿 《统计研究》 1987年第6期53-56,68,共5页
关于指数的数学形式及其性质的讨论有一个共同的特征,就是带有浓厚的数学形式主义和主观主义色彩。因此,它们不能科学地解释各种测验的实际经济分析涵义,更无法正确地阐明评价经济指数的基本标准是什么,以及不同性质的测验在指数的评价... 关于指数的数学形式及其性质的讨论有一个共同的特征,就是带有浓厚的数学形式主义和主观主义色彩。因此,它们不能科学地解释各种测验的实际经济分析涵义,更无法正确地阐明评价经济指数的基本标准是什么,以及不同性质的测验在指数的评价方法体系中占有何种地位。指数的数学性质测验只有与具体的经济分析问题联系起来,才有实际意义,从而构成经济指数评价方法体系中的一个有机部分。 展开更多
关键词 时间互换测验 循环测验 动态指数 数学测验 空间指数 基位 指数性 指数体系 经济指数 固定加权
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A Synoptic Snapshot of the East Cape Eddy(ECE)
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作者 LIUWei LIUQinyu 《Journal of Ocean University of China》 SCIE CAS 2005年第1期8-13,共6页
A synoptic snapshot in this study is made for the East Cape Eddy (ECE) basedon the World Ocean Circulation Experiment (WOCE) P14C Hydrographic Section and Shipboard ADCPvelocity vector data collected in September 1992... A synoptic snapshot in this study is made for the East Cape Eddy (ECE) basedon the World Ocean Circulation Experiment (WOCE) P14C Hydrographic Section and Shipboard ADCPvelocity vector data collected in September 1992. The ECE is an anticyclonic eddy, barotropicallystructured and centered at 33.64°S and 176.21°E, with warm and salinous-cored subsurface water.The radius of the eddy is of the order O (110 km) and the maximum circumferential velocity is O (40cm s^(-1)); as a result, the relative vorticity is estimated to be O (7 x 10^(-6)s^(-1)). Due to theexistence of the ECE, the mixed layer north of New Zealand becomes deeper, reaching a depth of 300m in the austral winter. The ECE plays an important role in the formation and distribution of theSubtropical Mode Water (STMW) over a considerable area in the South Pacific. 展开更多
关键词 east cape eddy (ECE) section P14C subtropical mode water (STMW)
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High Cycle Fatigue Life Prediction and Reliability Analysis of Aeroengine Blades
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作者 张俊红 林杰威 +1 位作者 张桂昌 刘海 《Transactions of Tianjin University》 EI CAS 2012年第6期456-464,共9页
Based on the nonlinear continuum damage model (CDM) developed by Chaboehe, a modified model for high cycle fatigue of TC4 alloy was proposed. Unsymmetrical cycle fatigue tests were conducted on rod specimens at room... Based on the nonlinear continuum damage model (CDM) developed by Chaboehe, a modified model for high cycle fatigue of TC4 alloy was proposed. Unsymmetrical cycle fatigue tests were conducted on rod specimens at room temperature. Then the material parameters needed in the CDM were obtained by the fatigue tests, and the stress distribution of the specimen was calculated by FE method. Compared with the linear damage model (LDM), the dam- age results and the life prediction of the CDM show a better agreement with the test and they are more precise than the LDM. By applying the CDM developed in this study to the life prediction of aeroengine blades, it is concluded that the root is the most dangerous region of the whole blade and the shortest life is 58 211 cycles. Finally, the Cox propor- tional hazard model of survival analysis was applied to the analysis of the fatigue reliability. The Cox model takes the covariates into consideration, which include diameter, weight, mean stress and tensile strength. The result shows that the mean stress is the only factor that accelerates the fracture process. 展开更多
关键词 life prediction RELIABILITY continuum damage model survival analysis Cox proportional hazard model aeroengine blade
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Circulating tumor cells in lung cancer:Detection methods and clinical impact
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作者 Minghui Zhang Decai Chi +3 位作者 Shu Zhao Yan Wang Maopeng Yang Yan Wan 《The Chinese-German Journal of Clinical Oncology》 CAS 2014年第10期476-482,共7页
Circulating tumor cells(CTCs) are tumor cells that enter the blood circulation after detaching from the primary tumor and can migrate to reach distant organs, where they can give rise to aggressive metastasis. Clinica... Circulating tumor cells(CTCs) are tumor cells that enter the blood circulation after detaching from the primary tumor and can migrate to reach distant organs, where they can give rise to aggressive metastasis. Clinical studies have revealed that the presence of CTCs in peripheral blood is correlated with disease progression in lung cancer. However, as CTCs are rare cancer cells released from tumors into the bloodstream, both enrichment and sensitive detection methods are technically challenging. In order to best understand how CTCs are currently being deployed, this review mainly focuses on the different detection methods for CTCs. Furthermore, we will describe the clinical impact of circulating tumor cells in lung cancer and discuss their potential use as biomarker to guide the prognosis. 展开更多
关键词 circulating tumor cells(CTCs) lung cancer enrichment method detection method
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Comparison of Procedures to Evaluate the Cyclic Stress-Strain Curve from Incremental Step Test
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作者 Giovanni Zonfrillo Duccio Nappini 《Journal of Mechanics Engineering and Automation》 2015年第6期362-369,共8页
The design of structural components in low-cycle fatigue field often requires the knowledge of the cyclic properties of the material, which are commonly described by the classical relation of Ramberg-Osgood. In order ... The design of structural components in low-cycle fatigue field often requires the knowledge of the cyclic properties of the material, which are commonly described by the classical relation of Ramberg-Osgood. In order to obtain the cyclic curve using experimental data from incremental step tests, four methodologies are described and critically discussed. Three methods differ in the procedure of evaluation of the elastic modulus, while in the last one the experimental data are interpolated with a single non-linear regression. The various techniques were applied to data obtained from tests carried out on stainless steel specimens, and the resulting differences were analysed and quantified. An average behaviour was evaluated considering the total set of data obtained from experimental tests. The choice of the most suitable method is related to both the strain range of interest and the goal for which the results are used. 展开更多
关键词 Cyclic curve incremental step test Ramberg-Osgood stainless steel.
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