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Application of grey relational analysis in sheet metal forming for multi-response quality characteristics

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第5期8卷 805-811页

作者： XIE Yan-min yu hu-ping CHEN Jun RUAN Xue-yu National Die ＆ Mold CAD Engineering Research Center Shanghai Jiao Tong University Shanghai 200030 China

The theory of grey systems is a new technique for performing prediction, relational analysis and decision making in many areas. In this paper, the use of grey relational analysis for optimizing the square hole flanging process parameters with considerations of the multiple response (the average flanging height, regular flanging and maximum strain) is introduced. Various flanging parameters, such as the blank inner radius rb, blank inner width B0, are considered. An orthogonal array is used for the experimental design. Multiple response values are obtained using finite element analysis (FEA). Optimal process parameters are determined by the grey relational grade obtained from the grey relational analysis for multi-performance characteristics (flanging height, regular flanging and maximum strain). Analysis of variance (ANOVA) for the grey relational grade is implemented. The results showed good agreement with the experiment result. Grey relational analysis can be applied in multiple response optimi-zation designs.

关键词： Grey relational analysis Flanging Multiple response Optimization design

Model Detection and Variable Selection for Varying Coefficient Models with Longitudinal Data

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Acta Mathematica Sinica,English Series 2016年第3期32卷 331-350页

作者： San Ying FENG yu ping hu Liu Gen XUE School of Mathematics and Statistics Zhengzhou University College of Applied Sciences Beijing University of Technology

In this puper, we consider the problem of variabie selection and model detection in varying coefficient models with longitudinM data. We propose a combined penalization procedure to select the significant variables, detect the true structure of the model and estimate the unknown regression coefficients simultaneously. With appropriate selection of the tuning parameters, we show that the proposed procedure is consistent in both variable selection and the separation of varying and constant coefficients, and the penalized estimators have the oracle property. Finite sample performances of the proposed method are illustrated by some simulation studies and the real data analysis.

关键词： Combined penalization longitudinal data model detection variable selection oracle property varying coefficient model

Tests for p-regression Coefficients in Linear Panel Model When p is Divergent

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Acta Mathematicae Applicatae Sinica 2020年第3期36卷 566-580页

作者： Jing ZHAO Mi-xia WU Wei-hu CHENG Yao-hua RONG yu-ping hu China National Institute of Standardization Beijing 100191China College of Applied Sciences Beijing University of TechnologyBeijing100124China School of Mathematics and Statistics Zhengzhou UniversityZhengzhou 450001China

This paper evaluates the performance of the FW-test for testing part of p-regression coefficients in linear panel data model when p is *** asymptotic power of the F_W-statistic is obtained under some regular *** theoretical development are challenging since the number of covariates increases as the sample size *** is worth noting that the inference approach does not require any specification of the error *** simulation comparisons are conducted and show that the simulated power coincide with theoretical power *** method is also illustrated using a renal cancer data example.

关键词： regression coefficient F_W-statistic Panel data

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微小尺度流动应力波动尺度效应

上海交通大学学报 2006年第6期40卷 906-908页

作者：申昱于沪平阮雪榆上海交通大学国家模具CAD工程研究中心上海200030

通过对常温下具有不同晶粒直径的微型铜圆柱体进行镦粗实验,研究了微小尺度下流动应力波动尺度效应现象.结果表明,在应变量相同条件下,流动应力波动幅度随晶粒尺寸的增大而线性增大;在晶粒尺寸相同条件下,流动应力波动幅度随应变量的增... 详细信息

通过对常温下具有不同晶粒直径的微型铜圆柱体进行镦粗实验,研究了微小尺度下流动应力波动尺度效应现象.结果表明,在应变量相同条件下,流动应力波动幅度随晶粒尺寸的增大而线性增大;在晶粒尺寸相同条件下,流动应力波动幅度随应变量的增大而增大.基于晶体塑性理论及数理统计理论,建立了流动应力波动幅度与晶粒尺寸和坯料几何尺寸间的关系.

关键词：微成形尺度效应流动应力波动

Persistent subretinal fluid after successful scleral buckle surgery for macula-off retinal detachment

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Chinese Medical Journal 2011年第23期124卷 4007-4011页

作者： WANG Xiao-yu SHEN Li-ping hu Rong-rong XU Wei Department of Ophthalmology First Affiliated Hospital of College of Medicine Zhejiang University Hangzhou Zhejiang 310003 China

Background After successful scleral buckle and cryotherapy for macular-off retinal detachment （RD）, some patients have poor visual acuity without any clinically detected macular change, and the unsatisfactory postoperative visual acuity is difficult to explain. The purpose of this study was to determine the characteristics of subretinal fluid （SRF） after successful scleral buckle surgery for macula-off RD. Methods Twenty-eight eyes from 28 patients were included in this study. The patients underwent scleral buckle surgery combined with cryopexy for macular-off RD. After surgery, all eyes underwent thorough ophthalmologic examinations including slit-lamp biomicroscopy, best-corrected visual acuity （BCVA） test, and binocular indirect ophthalmoscopy. The BCVA prior to the operation, duration of RD, the duration of postoperative retinal reattachment, BCVA when SRF was observed, period required for the SRF to become undetectable, and the BCVA at the final follow-up were included in the clinical data for this study. Optical coherence tomography （OCT） and B-ultrasonography were used to confirm SRF, and fluorescein angiography （FFA） was carried out in several patients. BCVA when SRF was observed and BCVA at the final follow-up were evaluated using a paired t test. Correlations between BCVA before the operation and duration of RD and BCVA at the final follow-up were analyzed using the Pearson correlation test. The type of SRF under OCT and BCVA at the final follow-up were compared using one-way analysis of variance （ANOVA）. Results Postoperative retinal reattachment was achieved in 1.0-7.0 days （average, （2.7±.2.1） days）. After retinal reattachment, SRF was detected in all eyes by OCT 2 weeks postoperative, while B ultrasonography found no changes. The mean IogMAR BCVA was 0.35±0.27 at the time of the detection of SRF. The period for SRF to become undetectable ranged from 2.0 to 11.0 months （average, （6.3±2.3） months）. The time of follow-up ranged from 24.0 to 36.0 months （a

关键词： subretinal fluid retinal detachment macula-off surgery

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微小尺度镦挤复合成形研究

塑性工程学报 2006年第1期13卷 58-61页

作者：申昱于沪平阮雪榆上海交通大学国家模具CAD工程研究中心上海200030

为了研究晶粒尺寸对微成形工艺的影响,在常温下对具有不同晶粒尺寸微型铜圆柱体坯料进行了微型镦挤复合成形,获得了微小尺度下材料流动特点及相关工艺参数。所得结果表明,所成形的微型杆-法兰件挤出杆端随着材料晶粒尺寸的增大而逐渐呈... 详细信息

为了研究晶粒尺寸对微成形工艺的影响,在常温下对具有不同晶粒尺寸微型铜圆柱体坯料进行了微型镦挤复合成形,获得了微小尺度下材料流动特点及相关工艺参数。所得结果表明,所成形的微型杆-法兰件挤出杆端随着材料晶粒尺寸的增大而逐渐呈现出凹凸不平的现象,即出现非均匀流动;随着晶粒尺寸的增大,凸模单位压力逐渐减小;晶粒尺寸的变化对于各个阶段成形力变化趋势没有明显的影响。

关键词：微成形尺度效应镦挤

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48MnV非调质钢热成形流动应力模型

塑性工程学报 2019年第4期26卷 187-193页

作者：鞠晓辉申昱胡俊张杰于沪平上海交通大学塑性成形技术与装备研究院

通过对48MnV非调质钢试样进行高温压缩试验,得到不同温度和应变速率下的流动应力曲线,分析了应力随应变的变化以及温度和应变速率对应力的影响规律,基于Zener-Hollomon参数建立了高温流动应力模型和动态再结晶体积分数模型。采用未参与... 详细信息

通过对48MnV非调质钢试样进行高温压缩试验,得到不同温度和应变速率下的流动应力曲线,分析了应力随应变的变化以及温度和应变速率对应力的影响规律,基于Zener-Hollomon参数建立了高温流动应力模型和动态再结晶体积分数模型。采用未参与模型建立的实验数据对所建立的流动应力模型和动态再结晶体积分数模型进行了验证。结果表明,所建模型与实验数据的符合程度较高,具有较好的可靠性。同时对微观组织进行了观察,随着应变速率的增加,同一温度下晶粒的尺寸逐渐变小。

关键词： 48MnV非调质钢高温流动应力模型动态再结晶体积分数模型流动应力

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流动应力下降尺度效应的数值模拟

上海交通大学学报 2006年第10期40卷 1667-1670页

作者：申昱于沪平阮雪榆上海交通大学国家模具CAD工程研究中心上海200030

采用率相关晶体塑性本构关系及弹塑性大变形增量有限元方法,通过在晶粒尺寸相同条件下模拟不同尺寸微型铜圆柱体镦粗实验,对流动应力下降尺度效应现象进行了数值模拟研究,获得了与实验及表面层模型较为一致的结果.结果表明,随着坯料尺... 详细信息

采用率相关晶体塑性本构关系及弹塑性大变形增量有限元方法,通过在晶粒尺寸相同条件下模拟不同尺寸微型铜圆柱体镦粗实验,对流动应力下降尺度效应现象进行了数值模拟研究,获得了与实验及表面层模型较为一致的结果.结果表明,随着坯料尺寸的减小,流动应力逐渐下降;晶体塑性理论能够解释并描述流动应力下降尺度效应现象,并在一定程度上对流动应力下降幅度做出预测.

关键词：微成形尺度效应晶体塑性流动应力

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基于Kriging模型的可靠度计算

上海交通大学学报 2007年第2期41卷 177-180,193页

作者：谢延敏于沪平陈军阮雪榆上海交通大学模具CAD国家工程研究中心上海200030

利用地质学中的Kriging方法,建立了结构可靠问题的Kriging模型.利用可靠度计算的方法,对已建立的Kriging近似模型进行了可靠度计算.结果表明:考虑各向异性的Kriging模型精度好于各向同性的Kriging模型;基于Kriging模型的可靠度计算,不... 详细信息

利用地质学中的Kriging方法,建立了结构可靠问题的Kriging模型.利用可靠度计算的方法,对已建立的Kriging近似模型进行了可靠度计算.结果表明:考虑各向异性的Kriging模型精度好于各向同性的Kriging模型;基于Kriging模型的可靠度计算,不仅能明显地减少计算量,而且降低了可靠计算中的非线性,提高了收敛速度.

关键词： Kriging 近似模型可靠度实验设计