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Detection of void and metallic inclusion in 2D piezoelectric cantilever beam using impedance measurements

S. SAMANTA, S. S. NANTHAKUMAR, R. K. ANNABATTULA, X. ZHUANG

《结构与土木工程前沿（英文）》 2019年第13卷第3期页码 542-556 doi: 10.1007/s11709-018-0496-0

摘要： The aim of current work is to improve the existing inverse methodology of void-detection based on a target impedance curve, leading to quick-prediction of the parameters of single circular void. In this work, mode-shape dependent shifting phenomenon of peaks of impedance curve with change in void location has been analyzed. A number of initial guesses followed by an iterative optimization algorithm based on univariate method has been used to solve the problem. In each iteration starting from each initial guess, the difference between the computationally obtained impedance curve and the target impedance curve has been reduced. This methodology has been extended to detect single circular metallic inclusion in 2D piezoelectric cantilever beam. A good accuracy level was observed for detection of flaw radius and flaw-location along beam-length, but not the precise location along beam-width.

关键词： piezoelectricity impedance curve mode shapes inverse problem flaw detection curve shifting

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Is there an inverted U-shaped curve?Empirical analysis of the Environmental Kuznets Curve in agrochemicals

Fei LI,Suocheng DONG,Fujia LI,Libiao YANG

《环境科学与工程前沿（英文）》 2016年第10卷第2期页码 276-287 doi: 10.1007/s11783-014-0700-y

摘要： As the largest contributor to water impairment, agriculture-related pollution has attracted the attention of scientists as well as policy makers, and quantitative information is being sought to focus and advance the policy debate. This study applies the panel unit root, heterogeneous panel cointegration, and panel-based dynamic ordinary least squares to investigate the Environmental Kuznets Curve on environmental issues resulting from use of agricultural synthetic fertilizer, pesticide, and film for 31 provincial economies in mainland China from 1989 to 2009. The empirical results indicate a positive long-run co-integrated relationship between the environmental index and real GDP per capita. This relationship takes on the inverted U-shaped Environmental Kuznets Curve, and the value of the turning point is approximately 10,000–13,000, 85,000–89,000 and over 160,000 CNY, for synthetic fertilizer nitrogen indicator, fertilizer phosphorus indicator and pesticide indicator, respectively. At present, China is subject to tremendous environmental pressure and should assign more importance to special agriculture-related environmental issues.

关键词： Environmental Kuznets Curve agrochemical China

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一种用于抑制相移误差和零级串扰的相移算法通用设计方法 None

Chao FANG, Yang XIANG, Ke-qi QI

《信息与电子工程前沿（英文）》 2018年第19卷第6期页码 809-814 doi: 10.1631/FITEE.1601692

摘要：为降低零级串扰和相移误差对光栅横向剪切干涉仪波前复原精度的影响，进一步提升光栅横向剪切干涉仪检测光刻镜头系统波像差精度，推导出一种设计光栅剪切干涉相移算法的一般表达式，给出相移算法的具体设计方法。根据该表达式和设计方法，可以针对不同的零级串扰和相移误差建立相应的4种相移算法，实现高精度系统波像差检测。同时设计和评价了一种新的13步相移算法，结果证明所推导的一般表达式的有效性和先进性。

关键词：测量；横向剪切干涉仪；相移算法；相位复原

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Novel decoupled framework for reliability-based design optimization of structures using a robust shifting

Mohammad Reza GHASEMI, Charles V. CAMP, Babak DIZANGIAN

《结构与土木工程前沿（英文）》 2019年第13卷第4期页码 800-820 doi: 10.1007/s11709-019-0517-7

摘要： In a reliability-based design optimization (RBDO), computation of the failure probability ( ) at all design points through the process may suitably be avoided at the early stages. Thus, to reduce extensive computations of RBDO, one could decouple the optimization and reliability analysis. The present work proposes a new methodology for such a decoupled approach that separates optimization and reliability analysis into two procedures which significantly improve the computational efficiency of the RBDO. This technique is based on the probabilistic sensitivity approach (PSA) on the shifted probability density function. Stochastic variables are separated into two groups of desired and non-desired variables. The three-phase procedure may be summarized as: Phase 1, apply deterministic design optimization based on mean values of random variables; Phase 2, move designs toward a reliable space using PSA and finding a primary reliable optimum point; Phase 3, applying an intelligent self-adaptive procedure based on cubic B-spline interpolation functions until the targeted failure probability is reached. An improved response surface method is used for computation of failure probability. The proposed RBDO approach could significantly reduce the number of analyses required to less than 10% of conventional methods. The computational efficacy of this approach is demonstrated by solving four benchmark truss design problems published in the structural optimization literature.

关键词： reliability-based design optimization trusses sensitivity analysis shifting technique cubic B-splines response surface method

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Learning curve of totally thoracoscopic pulmonary segmentectomy

Weibing Wu, Jing Xu, Wei Wen, Yue Yu, Xinfeng Xu, Quan Zhu, Liang Chen

《医学前沿（英文）》 2018年第12卷第5期页码 586-592 doi: 10.1007/s11684-017-0566-z

摘要：

Totally thoracoscopic pulmonary segmentectomy (TTPS) is a feasible and safe technique that requires advanced thoracoscopic skills and knowledge of pulmonary anatomy. However, data describing the learning curve of TTPS have yet to be obtained. In this study, 128 patients who underwent TTPS between September 2010 and December 2013 were retrospectively analyzed to evaluate the learning curve and were divided chronologically into three phases, namely, ascending phase (A), plateau phase (B), and descending phase (C), through cumulative summation (CUSUM) for operative time (OT). Phases A, B, and C comprised 39, 33, and 56 cases, respectively. OT and blood loss decreased significantly from phases A to C (P <0.01), and the frequency of intraoperative bronchoscopy for target bronchus identification decreased gradually (A, 8/39; B, 4/33; C, 3/56; P = 0.06). No significant differences were observed in demographic factors, conversion, complications, hospital stay, and retrieved lymph nodes among the three phases. Surgical outcomes and techniques improved with experience and volume. CUSUM_OT indicated that the learning curve of TTPS should be more than 72 cases.

关键词： thoracoscopic segmentectomy learning curve CUSUM

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SHIFTING TO A RECOMMENDED DIETARY PATTERN COULD PROMOTE SUSTAINABLE DEVELOPMENT OF THE ENVIRONMENT AND

《农业科学与工程前沿（英文）》 2023年第10卷第1期页码 73-82 doi: 10.15302/J-FASE-2023489

摘要：

● Shifting from the existing dietary patterns to the alternative recommended dietary pattern could enhance the sustainable development of environment and human health.

关键词： CHNS data cluster analysis dietary patterns sustainable development

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Numerical investigation of circle defining curve for two-dimensional problem with general boundaries

Chung Nguyen VAN

《结构与土木工程前沿（英文）》 2019年第13卷第1期页码 92-102 doi: 10.1007/s11709-018-0472-8

摘要： The scaled boundary finite element method (SBFEM) is applied to the static analysis of two dimensional elasticity problem, boundary value problems domain with the domain completely described by a circular defining curve. The scaled boundary finite element equations is formulated within a general framework integrating the influence of the distributed body force, general boundary conditions, and bounded and unbounded domain. This paper investigates the possibility of using exact geometry to form the exact description of the circular defining curve and the standard finite element shape function to approximate the defining curve. Three linear elasticity problems are presented to verify the proposed method with the analytical solution. Numerical examples show the accuracy and efficiency of the proposed method, and the performance is found to be better than using standard linear element for the approximation defining curve on the scaled boundary method.

关键词： exact geometry circular defining curve general boundaries SBFEM

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学习曲线及在工业生产运作研究中的应用综述

陈志祥

《中国工程科学》 2007年第9卷第7期页码 82-88

摘要：

学习曲线是一种通过生产者行为学习与经验积累而得到改进的生产产出的特征函数，利用学习曲线可以科学地制定成本计划，改善作业计划、劳动定额与劳力规划，质量改善等。对国际上的研究文献、学习曲线的表现形式及其特点进行分析，探讨了几个新的应用动向。

关键词：学习曲线运作管理行为研究

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Research on physical shape preserving curve reconstruction

TANG Kelun, ZHANG Xiangwei, CHENG Siyuan, XIONG Hanwei, ZHANG Hong

《机械工程前沿（英文）》 2007年第2卷第3期页码 305-309 doi: 10.1007/s11465-007-0054-2

摘要： Fusion of various data is an effective way to improve the precision and efficiency of acquiring information in reverse engineering. A method of physical shape preserving curve reconstruction is proposed to better realize the data fusion of coordinate measuring machine (CMM) and visual information. From the principle of materials mechanics, the strain energy of the curve corresponding to the distortion is advanced as the internal energy, and the elastic potential energy of the curve is established, using a few precise measured data points as the equilibrium position, to be the external energy. On the basis of the principle of variation calculus, the basic spline finite element method (B-spline FEM) is used to determine the equilibrium position of curve deformation. Numerical simulation indicates that there is an extremely good agreement between the new fitted curve and the actual curve.

关键词： information CMM Numerical simulation effective coordinate measuring

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Interpolation of a spline developable surface between a curve and two rulings

Alicia CANTÓN,Leonardo FERNÁNDEZ-JAMBRINA

《信息与电子工程前沿（英文）》 2015年第16卷第3期页码 173-190 doi: 10.1631/FITEE.14a0210

摘要： In this paper we address the problem of interpolating a spline developable patch bounded by a given spline curve and the first and the last rulings of the developable surface. To complete the boundary of the patch, a second spline curve is to be given. Up to now this interpolation problem could be solved, but without the possibility of choosing both endpoints for the rulings. We circumvent such difficulty by resorting to degree elevation of the developable surface. This is useful for solving not only this problem, but also other problems dealing with triangular developable patches.

关键词： Developable surfaces Spline surfaces Blossoms

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Principle and curve of planetary indexing cam mechanisms

LIU Ming-tao, ZHANG Ce, YANG Yu-hu

《机械工程前沿（英文）》 2006年第1卷第4期页码 475-478 doi: 10.1007/s11465-006-0063-6

摘要： A new type of planetary indexing cam mechanism called type !c is presented. The transmission principle of type !c is discussed. Based on the principle of formation of conjugate tooth contour, the equations of the cam s pitch curve are derived. The continuity and symmetry of the cam s pitch curve are also analyzed. It can be concluded that: 1) This type has no output institution so the output precision can be improved; 2) The asymmetrical two-ring structure is used to overcome dead point and its phase angle is equal to (π - 2π/n); 3) The continuous condition of the cam s pitch curve is that the average transmission ratio is -n in an intermittent motion period.

关键词： continuity planetary average transmission symmetry intermittent

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Development of surface reconstruction algorithms for optical interferometric measurement

Dongxu WU, Fengzhou FANG

《机械工程前沿（英文）》 2021年第16卷第1期页码 1-31 doi: 10.1007/s11465-020-0602-6

摘要： Optical interferometry is a powerful tool for measuring and characterizing areal surface topography in precision manufacturing. A variety of instruments based on optical interferometry have been developed to meet the measurement needs in various applications, but the existing techniques are simply not enough to meet the ever-increasing requirements in terms of accuracy, speed, robustness, and dynamic range, especially in on-line or on-machine conditions. This paper provides an in-depth perspective of surface topography reconstruction for optical interferometric measurements. Principles, configurations, and applications of typical optical interferometers with different capabilities and limitations are presented. Theoretical background and recent advances of fringe analysis algorithms, including coherence peak sensing and phase-shifting algorithm, are summarized. The new developments in measurement accuracy and repeatability, noise resistance, self-calibration ability, and computational efficiency are discussed. This paper also presents the new challenges that optical interferometry techniques are facing in surface topography measurement. To address these challenges, advanced techniques in image stitching, on-machine measurement, intelligent sampling, parallel computing, and deep learning are explored to improve the functional performance of optical interferometry in future manufacturing metrology.

关键词： surface topography measurement optical interferometry coherence envelope phase-shifting algorithm

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交换式以太网NC建模与实时性能分析

王晓欣,刘鲁源,刘昆,马津艳

《中国工程科学》 2006年第8卷第6期页码 55-59

摘要：

交换式以太网的实时性能分析是工业以太网研究领域的一个热点课题，目前还没有一个有效的数学模型来对其进行描述。通过对典型交换机结构的分析，应用网络微积分理论建立了交换机的服务曲线模型，该模型将交换机中的数据流分为实时数据和非实时数据，并得到了最大延迟值和最大缓存需求值等，最大延迟为交换机的实时应用提供了理论边界值，最大缓存需求值为在实时工业环境中的交换机构建提供了理论参考。

关键词：网络微积分交换机到达曲线服务曲线延迟

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三跨连续加劲梁悬索桥无索区梁段线形调整方法研究

戚兆臣,唐茂林,崔冰,董盟,王明

《中国工程科学》 2013年第15卷第8期页码 37-41

摘要：

三跨连续加劲梁悬索桥在桥塔处梁段刚接及体系转换时如何保证无索区的线形平顺过渡、顺利进行体系转换、确保成桥线形与内力一致是一个难度较高的技术课题。本文讨论了国内外无索区梁段进行体系转换的方法，并以一座超千米的三跨连续钢箱梁悬索桥为例，实现其无索区加劲梁体系转换、线形调整和施工控制。

关键词：悬索桥加劲梁无索区线形

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基于微笑曲线理论的中国建筑业核心竞争力研究

叶娟,刘宏蛟

《中国工程科学》 2008年第10卷第12期页码 86-91

摘要：

建国以来，中国建筑业产值一直稳步提高，但低效率、低收益问题仍然没有得到解决。基于拓展服务领域、增加附加价值以提高我国建筑业核心竞争力的思路，从“广义的建筑业”和“广义的建设项目生命周期”出发，构建了建筑业的工程价值体系，并定义了相对附加经济价值这一概念。根据对目前我国建筑业现状的分析结果，研究了建设项目生命周期各个不同阶段附加价值的增值特点，做出了我国不同时期建筑业的微笑曲线，预测了我国建筑业未来的发展方向，最后探讨了提升我国建筑业核心竞争力的上、中、下游和整体发展战略。

关键词：建筑业核心竞争力微笑曲线相对附加经济价值全生命周期