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A NOTE ON LAGRANGE INTERPOLATION OF FUNCTIONS OF GENERALIZED BOUNDED VARIATION

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Analysis in Theory and Applications 1993年第4期9卷 1-8页

作者： sun xiehua china institute of metrology,china Division of Mathematics China Institute of Metrology Hangzhou PRC

In this paper we solve a remained problem in[2],whether the following estimate approximation for the class f∈C[-1,1]∩BV by Lagrange interpolation based on the Jacobi abscissasi,L_n^(α,β)(f,x)-f(x) =Ο(1/n)holds,i... 详细信息

关键词： interpolation Jacobi holds sided quadrature grange valid raised 乏气 observing

ON THE DEGREE OF APPROXIMATION BY WAVELET EXPANSIONS

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Analysis in Theory and Applications 1998年第1期14卷 81-90页

作者： sun xiehua (china institute of metrology, china) Division of Mathematics China Institute of Metrology Hangzhou Zhejiang PR China

In this paper we estimate the degree of approximation of wavelet expansions. Our result shows that the degree has the exponential decay for function f(x)∈L2 continuous in a finite interval (a, b) which is much superi... 详细信息

关键词： ON THE DEGREE OF APPROXIMATION BY WAVELET EXPANSIONS

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扫描线种子填充算法的改进

计算机工程 2000年第12期26卷 142-143页

作者：孙燮华中国计量学院计算机科学与技术系杭州310034

提出了一种扫描线种子填充算法的改进算法, 其填充速度得到很大提高。

关键词：计算机图形学种子填充算法扫描线

Origin and evolution of false brinelling and fretting corrosion under rolling conditions

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Friction 2024年第4期12卷 618-631页

作者： Xin JIA Lu HUANG Miao sun Wenbin LI National institute of metrology Beijing 100029China Yantai Tiancheng Machinery Co. Ltd.Yantai 264006China

Rolling bearings working in oscillating applications often suffer from false brinelling and fretting corrosion that limit their service *** present,the study of oscillation-induced failures is primarily dominated by a large number of sliding and bench ***,most of the previous work are not able to fully describe the two closely related but different failure *** this study,the origin and evolution of the two failures are thoroughly investigated under strictly controlled oscillating rolling *** results show that failure evolves from false brinelling to fretting corrosion under dry friction conditions regardless of the oscillation *** process is accompanied by a large area peeling and serious oxidation,and the oxygen content increases from 2.50 wt%to 21.22 wt%.Oxidation is a crucial factor in the evolution of false brinelling into fretting ***,the distribution of microwear and oxygen content depend on the oscillation *** lubrication conditions,the friction coefficient(COF)is smaller in the initial stage and led to local slip or transient instability of rolling ***,the size of the wear marks and COF increased and appeared to be larger than those under a dry friction ***,grease can separate the contact surfaces,only surface deformation owing to false brinelling and slight damage at the roughness level *** evolution of false brinelling and fretting corrosion is also closely related to residual *** brinelling often occurrs with residual stress accomulation,meanwhile,the residual stress increases from 120 to 300 *** peeling occurs,residual stress is *** failure pattern transformed from false brinelling to fretting corrosion and is accompanied by *** far,none of investigation is able to show satisfactory evolution of oscillating-induced failures,this study may contribute to more scientific understanding of rolling bearings against long-

关键词： oscillating false brinelling fretting corrosion wear residual stress

A review on the chemical speciation and influencing factors of heavy metals in Municipal Solid Waste landfill humus

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Waste Disposal and Sustainable Energy 2024年第2期6卷 209-218页

作者： Qiongyu sun Bo sun Defeng Wang Yuyuan Pu Mingxiu Zhan Xu Xu Jinqing Wang Wentao Jiao College of metrology and Measurement Engineering China Jiliang UniversityHangzhou 310018Zhejiang ProvinceChina Zhongke Hualu Soil Remediation Engineering Co. LtdDezhou 253011Shandong ProvinceChina Zhejiang Environmental Protection Group Co. LtdHangzhou 310020Zhejiang ProvinceChina institute for Thermal Power Engineering Zhejiang UniversityHangzhou 310027Zhejiang ProvinceChina Research Center for Eco-Environmental Sciences Chinese Academy of SciencesHaidian District18 Shuangqing RoadBeijing 100085China

Heavy metal pollution in landfill humus can cause serious environmental problems and may endanger soil ecosystems and human *** biological toxicity of heavy metals is not only related to their total amount but also influenced to a greater extent by the distribution of their chemical *** the different chemical speciation and proportions of heavy metals can provide a more comprehensive and accurate understanding of the pollution characteristics and biological toxic-ity of heavy metals in landfill *** on a review of the relevant literature,this paper systematically summarizes the recent research status of typical heavy metal chemical speciation in landfill *** chemical speciation is diverse and *** instance,heavy metals in residual states and organically bound states have little impact on organisms,while heavy metals in exchangeable states and Fe-Mn oxide states can easily migrate and *** chemical speciation of heavy metals is affected by many factors,among which the soil pH and organic matter content are some of the most important ***,the existing gaps in the current research on the chemical speciation of heavy metals in landfills are described and future research directions are *** work provides a theoretical reference for researching the restoration of heavy metal-contaminated humus soil and the resource utilization of humus soil.

关键词： Landflls Humus soil containing heavy metal-Chemical speciation Distribution characteristics Influencing factors

Repetitive learning control of nonlinear systems over finite intervals

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Science china(Information Sciences) 2010年第1期53卷 115-128页

作者： sun MingXuan1, WANG DanWei2 & CHEN PengNian3 1College of Information Engineering, Zhejiang University of Technology, hangzhou 310014, china 2School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639794 3Department of Mathematics, china institute of metrology, hangzhou 310018, china College of Information Engineering Zhejiang University of Technology Hangzhou China School of Electrical and Electronic Engineering Nanyang Technological University Singapore Singapore Department of Mathematics China Institute of Metrology Hangzhou China

Iterative learning control requires initial repositioning, while the time functions to be learned should be of periodicity in repetitive control. However, there are cases in practice where the time-varying unknowns are not periodic but repetitive, and repetitive learning control is applicable with avoidance of initial repositioning. In this paper, repetitive learning control designs are presented for a broader class of nonlinear systems over finite intervals. The Freeman formula is modified and used for stabilization of the nominal nonlinear time-varying system undertaken. The global stability of the learning system and asymptotic convergence of the tracking error are established through analysis of both partially and fully saturated learning algorithms, respectively. The repetitive learning control method is theoretically shown to be effective in dealing with time-varying parametric uncertainties.

关键词： Initial condition problem convergence iterative learning control repetitive control repetitive learning control nonlinear systems

ON THE EXACT DEGREE OF APPROXIMATION BY HERMITE-FEJER INTERPOLATION BASED ON THE LAGUERRE ABSCISSAS

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Applied Mathematics(A Journal of Chinese Universities) 2006年第4期21卷 405-410页

作者： Shen Yunhai sun xiehua Zhejiang Water Conservancy and Hydropower College Hangzhou 310018 China. Department of Computer Science China Institute of Metrology Hangzhou 310018 China.

For the nonpositive Hermite-Fejér interpolation based on the Laguerre abscissas, a pointwise two-sided estimate of the degree of approximation in the aleatoric interval [0, A] is first established.

关键词： Hermite-Fejér interpolation Laguerre abscissas two-sided estimate degree of approximation.

Improvements in Iodine Stabilized He-Ne Easers at 474 THz (633 nm) with Compatible System of Third and Fifth Harmonic Locking

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计量学报 1991年第S1期12卷 1-5页

作者： Shen Naicheng,Wang Chu,Wang Zhongwu,Zhang Xuebin and sun Yimin(National institute of metrology,Beijing,china) (Peking University,Beijing,china)

We have developed two 474 THz(633 nm)new iodine stabilized He-Ne lasers with compatible system of third and fifth harmonic *** frequency stability is 1.0×10-11/ 1s and 3.5×10-12 / 10s with third harmonic locking,and corresponding values are 1.3×10-11/1s and 4.0×10-12/ 10s with fifth harmonic *** found that the frequency difference between the same component with third and fifth harmonic locking are from 5 kHz to SO *** experiment and analysis indicate that the center of fifth harmonic signals is closer to the Lorentzian center in iodine absorption component than one of the third harmonic signals,and the reproducibility with fifth harmonic locking is also better than one with third harmonic locking.

关键词： locking nm harmonic Iodine fifth iodine compatible closer stabilized insensitive

Advancing large-scale thin-film PPLN nonlinear photonics with segmented tunable micro-heaters

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Photonics Research 2024年第8期12卷 1703-1708页

作者： XIAOTING LI HAOCHUAN LI ZHENZHENG WANG ZHAOXI CHEN FEI MA KE ZHANG WENZHAO sun CHENG WANG Department of Electrical Engineering City University of Hong Kong School of Physics Sun Yat-sen University City University of Hong Kong (Dongguan) Center of Information and Communication Technology City University of Hong Kong Shenzhen Research Institute State Key Laboratory of Terahertz and Millimeter Waves City University of Hong Kong

Thin-film periodically poled lithium niobate (TF-PPLN) devices have recently gained prominence for efficient wavelength conversion processes in both classical and quantum applications. However, the patterning and poling of TF-PPLN devices today are mostly performed at chip scales, presenting a significant bottleneck for future largescale nonlinear photonic systems that require the integration of multiple nonlinear components with consistent performance and low cost. Here, we take a pivotal step towards this goal by developing a wafer-scale TF-PPLN nonlinear photonic platform, leveraging ultraviolet stepper lithography and an automated poling process. To address the inhomogeneous broadening of the quasi-phase matching(QPM) spectrum induced by film thickness variations across the wafer, we propose and demonstrate segmented thermal optic tuning modules that can precisely adjust and align the QPM peak wavelengths in each section. Using the segmented micro-heaters, we show the successful realignment of inhomogeneously broadened multi-peak QPM spectra with up to 57% enhancement of conversion efficiency. We achieve a high normalized conversion efficiency of 3802% W-1cm-2in a 6 mm long PPLN waveguide, recovering 84% of the theoretically predicted efficiency in this device. The advanced fabrication techniques and segmented tuning architectures presented herein pave the way for wafer-scale integration of complex functional nonlinear photonic circuits with applications in quantum information processing, precision sensing and metrology, and low-noise-figure optical signal amplification.

关键词： Lithium niobate Optical amplifiers Optical parametric oscillators Optical signals Precision metrology Wavelength conversion